Monday, November 12, 2018

Where Is Spacetime Formed?



Most physicists believe that the structure of spacetime is formed in an unknown way in the vicinity of the Planck scale, i.e. at distances close to one trillionth of a trillionth of a metre. However, careful considerations undermine the unambiguity of this prediction. There are quite a few arguments in favour of the fact that the emergence of spacetime may occur as a result of processes taking place much "closer" to our reality: at the level of quarks and their conglomerates.

What is spacetime? The absolute, unchanging, ever- and omni-present arena of events? Or perhaps it is a dynamic creation, emerging in some way on a certain scale of distance, time or energy? References to the absolute are not welcome in today's physics. It is widely believed that spacetime is emergent. It is not clear, however, where the process of its emergence takes place.

Just as the interactions between sand grains form a smooth surface on the beach, the spacetime known to us could be the result of relations between quarks and their conglomerates.

Credit:  IFJ PAN

The majority of physicists tend to suppose that spacetime is created on the Planck scale, at distances close to one trillionth of a trillionth of a metre (~10-35 m). In his article in Foundations of Science, Professor Piotr Zenczykowski from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow systematizes the observations of various authors on the formation of spacetime, and argues that the hypothesis about its formation at the scale of quarks and hadrons (or quark aggregates) is quite sensible for a number of reasons.


Questions about the nature of space and time have puzzled humanity since at least antiquity. Are space and time separated from matter, creating a "container" for motions and events occurring with the participation of particles, as Democrit proposed in the 5th century BC? Or perhaps they are attributes of matter and could not exist without it, as Aristotle suggested a century later? Despite the passage of millennia, these issues have not been resolved yet. Moreover, both approaches - albeit so contradictory! - are deeply ingrained into the pillars of modern physics. In quantum mechanics, events take place in a rigid arena with uniformly flowing time. Meanwhile, in the general theory of relativity, matter deforms elastic spacetime (stretching and twisting it), and spacetime tells particles how to move. In other words, in one theory the actors enter an already prepared stage to play their roles, while in the other they create the scenography during the performance, which in turn influences their behaviour.

In 1899, German physicist Max Planck noticed that with certain combinations of some constants of nature, very fundamental units of measurement could be obtained. Only three constants - the speed of light c, the gravitational constant G and Planck's constant h - were sufficient to create units of distance, time and mass, equal (respectively) to 1.62 · 10-35 m, 5.39 · 10-44 s and 2.18 · 10-5 g. According to today's mainstream belief, spacetime would be created at Planck's length. In fact, there are no substantive arguments for the rationality of this hypothesis.

Both our most sophisticated experiments and theoretical descriptions reach the scale of quarks, i.e. the level of 10-18 m. So how do we know that along the way to Planck's length - over a dozen consecutive, ever smaller orders of magnitude - spacetime retains its structure? In fact, we are not even sure if the concept of spacetime is rational at the level of hadrons! Divisions cannot be carried out indefinitely, because at some stage the question of the next smaller part simply ceases to make sense. A perfect example here is temperature. This concept works very well on a macro scale, but when, after subsequent divisions of matter, we reach the scale of individual particles, it loses its raison d'etre.

"At present, we first seek to construct a quantized, discrete spacetime, and then 'populate' it with discrete matter. However, if spacetime was a product of quarks and hadrons, the dependence would be reversed: the discrete character of matter should then enforce the discreteness of spacetime!" says Prof. Zenczykowski, and adds: "Planck was guided by mathematics. He wanted to create units from the fewest constants possible. But mathematics is one thing, and the relationship with the real world is another. For example, the value of Planck's mass seems suspicious. One would expect it to have a value rather more characteristic for the world of quanta. In the meantime, it corresponds to approximately 1/10 of the mass of a flea, which is most certainly a classical object."

Since we want to describe the physical world, we should lean towards physical rather than mathematical arguments. And so, when using Einstein's equations we describe the Universe at large scales, and it becomes necessary to introduce an additional gravitational constant, known as the cosmological constant Lambda. If, therefore, while constructing fundamental units, we expand the original set of three constants by Lambda, in the case of masses we obtain not one but three fundamental values: 1.39 · 10-65 g, 2.14 · 1056 g, and 0.35 · 10-24 g. The first of these could be interpreted as a quantum of mass, the second is at the level of the mass of the observable Universe, and the third is similar to the masses of hadrons (for example, the mass of a neutron is 1.67 · 10-24 g). Similarly, after taking Lambda into account, a unit of distance of 6.37 · 10-15 m appears, very close to the size of hadrons.

"Playing games with constants, however, can be risky because a lot depends on which constants we choose. For example, if spacetime was indeed a product of quarks and hadrons, then its properties, including the velocity of light, should also be emergent. This in turn means that the velocity of light should not be among the basic constants," notices Prof. Zenczykowski.

Another factor in favour of the formation of spacetime at the scale of quarks and hadrons are the properties of the elementary particles themselves. For example, the Standard Model does not explain why there are three generations of particles, where their masses come from, or why there are so-called internal quantum numbers, which include isospin, hypercharge and colour. In the picture presented by Prof. Zenczykowski these values can be linked to a certain six-dimensional space created by the positions of particles and their momenta. The space thus constructed assigns the same importance to the positions of particles (matter) and their movements (processes). It turns out that the properties of masses or internal quantum numbers can then be a consequence of the algebraic properties of 6D space. What's more, these properties would also explain the inability to observe free quarks.

"The emergence of spacetime may be associated with changes in the organization of matter occurring at a scale of quarks and hadrons in the more primary, six-dimensional phase space. However, it is not very clear what to do next with this picture. Each subsequent step would require going beyond what we know. And we do not even know the rules of the game that Nature is playing with us, we still have to guess them! However, it seems very reasonable that all constructions begin with matter, because it is something physical and experimentally available. In this approach, spacetime would only be our idealization of relations among elements of matter," sums up Prof. Zenczykowski.

The Henryk Niewodniczanski Institute of Nuclear Physics (IFJ PAN) is currently the largest research institute of the Polish Academy of Sciences. The broad range of studies and activities of IFJ PAN includes basic and applied research, ranging from particle physics and astrophysics, through hadron physics, high-, medium-, and low-energy nuclear physics, condensed matter physics (including materials engineering), to various applications of methods of nuclear physics in interdisciplinary research, covering medical physics, dosimetry, radiation and environmental biology, environmental protection, and other related disciplines. The average yearly yield of the IFJ PAN encompasses more than 600 scientific papers in the Journal Citation Reports published by the Thomson Reuters. The part of the Institute is the Cyclotron Centre Bronowice (CCB) which is an infrastructure, unique in Central Europe, to serve as a clinical and research centre in the area of medical and nuclear physics. IFJ PAN is a member of the Marian Smoluchowski Kraków Research Consortium: "Matter-Energy-Future" which possesses the status of a Leading National Research Centre (KNOW) in physics for the years 2012-2017. The Institute is of A+ Category (leading level in Poland) in the field of sciences and engineering.







Contacts and sources:
Prof. Piotr Zenczykowski
The Henryk Niewodniczanski Institute of Nuclear Physics (IFJ PAN)

Citation: "Quarks, Hadrons, and Emergent Spacetime"
P. Zenczykowski
Foundations of Science (2018), pp 1-19

DOI: https://doi.org/10.1007/s10699-018-9562-2
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Tiny Footprints, Big Discovery

UNLV geologist Stephen Rowland discovered that a set of 28 footprints left behind by a reptile-like creature 310 million years ago are the oldest ever to be found in Grand Canyon National Park. 

Courtesy of Stephen Rowland


Hundreds of hikers each day pass by the fallen boulder along the Bright Angel Trail in Grand Canyon National Park.

It might otherwise go unnoticed except for the 28 indentations — sloping footprints left behind by a small, reptile-like creature about 310 million years ago — that cover the rock’s expansive surface.

“It’s the oldest trackway ever discovered in the Grand Canyon in an interval of rocks that nobody thought would have trackways in it, and they’re among the earliest reptile tracks on earth,” said Steve Rowland, UNLV professor of geology who is studying the fossil trackways.An illustration by Stephen Rowland of the reptile-like creature making the tracks.

Rowland, who presented his findings at the recent annual meeting of the Society of Vertebrate Paleontology, said he’s not prepared to say that they’re the oldest tracks of their kind ever discovered, but it’s a possibility, as he’s still researching the discovery.

“In terms of reptile tracks, this is really old,” he said, adding that the tracks were created as the supercontinent Pangaea was beginning to form.

Rowland was first alerted to the tracks in spring 2016 by a colleague who was hiking the trail with a group of students. The boulder ended up along the trail after the collapse of a cliff.

A year later, Rowland studied the footprints up close.

“My first impression was that it looked very bizarre because of the sideways motion,” Rowland said. “It appeared that two animals were walking side-by-side. But you wouldn’t expect two lizard-like animals to be walking side-by-side. It didn’t make any sense.”

When he arrived home, he made detailed drawings and began hypothesizing about the “peculiar, line-dancing gait” left behind by the creature.

An illustration by Stephen Rowland of the reptile-like creature making the tracks.
Credit: Stephen Rowland

“One reason I’ve proposed is that the animal was walking in a very strong wind, and the wind was blowing it sideways,” he said.

Another possibility is that the slope was too steep, and the animal sidestepped as it climbed the sand dune. Or, Rowland said, the animal was fighting with another creature, or engaged in a mating ritual.

“I don’t know if we’ll be able to rigorously choose between those possibilities,” he said.

He plans to publish his findings along with geologist Mario Caputo of San Diego State University in January. Rowland also hopes that the boulder is soon placed in the geology museum at the Grand Canyon National Park for both scientific and interpretive purposes.

Meanwhile, Rowland said that the footprints could belong to a reptile species that has never yet been discovered.

“It absolutely could be that whoever was the trackmaker, his or her bones have never been recorded,” Rowland said.



Contacts and sources:
Natalie Bruzda
University of Nevada, Las Vegas
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Whatever Happened to Limbo?



A research study from Queen's has found that the belief in Limbo – a place for unbaptised babies - has declined throughout the decades in Ireland due to the changing beliefs and values of the nation.

Limbo, in Catholic theology, was believed to be the border place between heaven and hell where those souls who died without being baptized, though not condemned to punishment, were deprived of eternal happiness with God in heaven.

Children growing up in the Ireland of the 1950s will have a clear remembrance of a metaphysical space or place known as Limbo. For Catholics, though not Irish Protestants, this formed part of a spiritual cosmos which viewed Heaven and Hell as opposite poles, with Purgatory and Limbo occupying rather vaguely defined intermediate positions.

The study was led by Professor Liam Kennedy, Professor Emeritus of History from the Institute of Irish Studies at Queen's University, who conducted a survey questionnaire in association with the Irish Countrywomen's Association.

Some 26 women in total, including 23 from the Irish Countrywomen's Association, took part in the survey which was carried out in 2017. The women varied in ages, with birth dates ranging from the 1930s - 1960s and represented all four provinces of the island of Ireland.

 Christ in Limbo
Bosch follower Christ in Limbo Philadelphia.jpg
Credit:  Philadelphia Museum of Art / Wikimedia Commons

Professor Kennedy explained: "The term Limbo does not appear in the Bible or the New Testament. It seems the concept was developed over time by Christians to handle two problems: one was the fate of those who led just lives and who died before Christ came on earth to redeem humankind; the other was the fate of unbaptised babies in the event of death.

"Children growing up in the Ireland of the 1950s will have a clear remembrance of a metaphysical space or place known as Limbo. For Catholics, though not Irish Protestants, this formed part of a spiritual cosmos which viewed Heaven and Hell as opposite poles, with Purgatory and Limbo occupying rather vaguely defined intermediate positions. But Limbo appears to have disappeared off the spiritual map."

In Ireland, understandings of Limbo, along with Heaven, Hell and Purgatory, were handed down by parents, schoolteachers, priests and nuns, drawing on the teachings of the Catholic Church.


"Catholics in Ireland, from the 1960s onwards, turned their backs on a religious belief they found not credible or even cruel and the institutional church itself placed less and less emphasis on the 'doctrine' of Limbo.

"A fear of Limbo drove parents to have their new-born child baptised as soon as was practicable. Otherwise, the infant risked losing eternal happiness and going into a void called Limbo. I have little doubt that mothers who had miscarriages or still-births suffered mental anguish as a result of the death of an unbaptised foetus or still-birth. Heaven was closed to the unbaptised, as indeed was consecrated Church ground," Professor Kennedy said.

In the study, 75 per cent of respondents felt the decline of belief in Limbo was due to the changing beliefs and values of the Catholic laity in Ireland, rather than change emanating from the centre of the Catholic Church in Rome.

However, 25 per cent of respondents believed that the teaching authority of the Catholic Church – in other words the Pope and the hierarchy – was the source of change.

Comments from respondents in the survey include:
'More people [were] less accepting of Church/Catholic myths'.
'Young people became more educated and began to question stuff that did not make sense to them. They were no longer afraid of the "fire and brimstone" that our previous generations were afraid to question.'
'People think Limbo is a ... cruel place and don't think that children go there. They believe in a more merciful God and that children will go to Heaven directly.'
'Because people didn't buy it anymore'.

Speaking about their own experience of Limbo, a respondent in the study said: "I was the eldest of ten children. But in 1954 I had a sister born named Marian (as it was Marian year in Ireland). She was born on a Saturday but died the next day.

"As was customary then my dad had to take her little body late at night well after dark to an old graveyard and on the perimeter of the graveyard. My dad had to bury her with no grave markings (an unknown grave). But at the time he made a little cross shape tied together with twine, made from two sticks and stuck them in the ground. Every year my dad used to take me to Marian's grave to say a little prayer."


Marie O'Toole, President of the ICA said: "ICA members were delighted to be invited to contribute to this worthwhile project by way of memories dating back to their youth, on the subject of Limbo. Some of them had very traumatic tales to tell, however, I suppose we lived in a different era then and believed everything we were told."

The study also found that there was a movement towards late baptism in recent times which meant that the mother, who was rarely at the baptism ceremony, was present at the moment of introducing the infant into her community of faith. Previously the mother would not have been present as the baptism as they were held almost immediately after birth.


Professor Kennedy concluded: "The survey was primarily concerned with belief in Limbo and its subsequent demise, as seen from the viewpoint of women. As the decades have gone by, belief in Limbo has withered. So much so that in this present day hardly any of those born in the new millennium will have the slightest notion of what Limbo was (or is), other than as a colloquial expression for being in some indeterminate mood or situation, as for example in the feeling of being 'in Limbo'. But it really did matter for the best part of a thousand years and gave rise to both fear and pain."

For more information on the study, please visit: http://www.qub.ac.uk/home/Filestore/Filetoupload,845202,en.pdf

 
Contacts and sources:
Zara McBrearty
Queen's University Belfast

Citation: Whatever Happened to Limbo? Irish Mothers Reflect on the Fate of the Unbaptised Infant A Report compiled with the assistance of the Irish Countrywomen’s Association     . http://www.qub.ac.uk/home/Filestore/Filetoupload,845202,en.pdf

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The Monkey Gaze Fixation and Dopamine

A University of Tsukuba-led study of gaze fixation in monkeys and their refusal to redirect the gaze onto a target in return for a reward reveals that dopamine neurons are key to inhibiting preplanned actions.

Among the diversity of behaviors implemented by the brain, the prevention of actions that might be beneficial in a certain context, but counterproductive or harmful in another, is particularly important. Some insights into how the brain achieves this have been obtained, but much remains unclear, including the involvement of the neurotransmitter dopamine. Shedding light on this would explain much about how behavioral control is achieved, and could help treat diseases in which inhibition of certain actions is impaired.

In a study involving analyses of gaze fixation and the visual tracking of targets in rhesus monkeys, researchers at University of Tsukuba have shown that the brain’s dopamine system is key to the subsequent inhibition of actions that have already been planned

Monkey Gaze Study Shows Dopamine's Role in Response Inhibition

Credit: University of Tsukuba

In this work, reported in the journal Neuron, the team placed two monkeys in front of a computer screen and, using the provision of rewards in the form of drinks, trained them to direct their gaze at targets on the screen presented in different patterns. The monkeys were trained to redirect their attention away from the center of the screen to another target in 70% of the trials, but to resist the temptation to do this in 30% of the trials when signaled to do so.

At the same time as looking at the screen and undergoing visual scans using an infrared eye-tracking system, the neuronal activity of the monkeys was also measured, at single-neuron resolution. Specifically, the researchers recorded approximately 40 dopamine-related neurons in each of the monkeys, and analyzed the correlations between their activities and success or failure in resisting redirecting their gaze to a new target in the 30% of trials.

“Using this experimental setup, we found that these dopaminergic neurons tended to be active when the monkeys successfully resisted the urge to redirect their gaze,” Masayuki Matsumoto says. “We then confirmed that it was the dopaminergic system that caused this response inhibition by injecting drugs that block dopaminergic neurotransmission.”

The team’s findings reveal details about the specific brain regions and neurological pathways involved in this response inhibition, showing that dopaminergic neurons in the substantia nigra as well as striatal neurons are key to canceling a previously planned action. The duration of the pause between the initial command and the subsequent inhibitory counter-command also influenced the monkeys’ success in the trials, providing hints about the mechanisms involved.

“Now that we know more about how preplanned actions are inhibited in the brain, we may be able to develop treatments for conditions involving impaired inhibition, such as Parkinson’s disease,” says lead author Takaya Ogasawara.


Full bibliographic information

The article
Attached files

Contacts and sources:
University of Tsukuba

Citation:  “The Primate Nigrostriatal Dopamine System Regulates Saccadic Response Inhibition” is published in Neuron at doi: 10.1016/j.neuron.2018.10.025.

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Allergy Chip Detects Allergens from Dried Blood Cheaply

Using the Allergy Chip co-developed by MedUni Vienna, sensitization to allergens can be detected early on. This normally requires a doctor taking a blood sample for subsequent analysis in a laboratory equipped with the Chip.

In Austria, provision is excellent and there are enough laboratories offering this new test. Elsewhere, however, there are only a few per country – blood samples are therefore often protected as well as possible, carefully packed, chilled and air-freighted for analysis. That is a complicated and expensive process.

 A MedUni Vienna team led by lead investigator Rudolf Valenta from the Institute of Pathophysiology and Allergy Research has now shown that this multi-allergen test works just as well with dried blood. Just a few drops of blood dried on a strip of Whatman paper (the extremely absorbent blotting paper most commonly used throughout the world) are enough. 


Credit: Medical University of Vienna

This discovery by the Viennese researchers was inspired by the experience gained from the new-born screening programme run by MedUni Vienna’s Department of Pediatrics and Adolescent Medicine for more than 50 years. In this programme, a small prick of blood is taken from the heel of new-born babies and put onto blotting paper to screen babies for any congenital diseases. "What works well here should also work in the allergy screening developed at MedUni Vienna," say Valenta and study lead author, Victoria Garib.

Dried blood samples provide just as much information as fresh serum

The main finding is as follows: The dried blood samples taken by a doctor produce the same results as analysing fresh serum. And this is true no matter how long the dried specimen has been in a plastic envelope or in the post or at what temperature it was applied. Says Garib: "We measured it at temperatures of +37°C, -20°C and +4°C. The result was always the same." The test involves stamping a small piece out of the paper and mixing it with a liquid in a plastic thimble, filtering out the antibodies in a centrifuge and then applying it to the Allergy Chip.

"This means that we are now giving every doctor in the world the ability to obtain an analysis quickly and easily, even if they only have a few patients with suspected allergies and do not have a laboratory nearby, so that they can help patients quickly," adds Valenta, also clarifying: "Of course, laboratories must not accept dried blood samples sent in by private individuals. A doctor must first establish whether the test is necessary and then take the blood sample properly and send it on." And this would only cost the same as a standard letter, just a few euros. By way of comparison: sending a chilled, correctly protected and packaged blood sample by airmail costs between €250 and €400. At the same time, say the Vienna researchers, it is possible to use the dried blood samples and antibodies obtained from them to evaluate the efficacy of allergy-related immunotherapy treatments and to monitor treatment.

About the Allergy Chip

The Allergy Chip, which was co-developed at MedUni Vienna by Valenta's working group, detects potential allergies by means of fluorescent-labelled antibodies. Currently, serum can be tested for more than 100 allergens at once, ranging from apple to pollen, from grasses, food allergens and bee stings right through to various essentially harmless substances in the environment, such as house dust. It is especially important to identify allergies in children at an early stage, to prevent subsequent chronic diseases such as asthma, for example. The Chip has now become established worldwide as the safest method for early detection of allergies.

 Journal of Allergy and Clinical Immunology: „Determination of IgE and IgG reactivity to more than 170 allergen molecules in paper dried blood spots“. V. Garib, E. Rigler, F. Gastager, R. Campana, Y. Dorofeeva, P. Gattinger, Y. Zhernov, M. Khaitov, R. Valenta. DOI: https://doi.org/10.1016/j.jaci.2018.08.047.

The present study was produced within the framework of the International Network of Universities for Molecular Allergology and Immunology (www.inunimai.org), which currently incorporates ten countries. In addition to Austria, these are Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Lithuania, Russia, the Ukraine and Uzbekistan. The study was funded by the Austrian Science Fund FWF (http://www.allergy-research-program.at/cms/). Rudolf Valenta is also a member of the Comprehensive Cancer Center Vienna, MedUni Vienna/Vienna General Hospital.
www.meduniwien.ac.at

 


Contacts and sources:
Medical University of Vienna


Citation:  Journal of Allergy and Clinical Immunology
„Determination of IgE and IgG reactivity to more than 170 allergen molecules in paper dried blood spots“. V. Garib, E. Rigler, F. Gastager, R. Campana, Y. Dorofeeva, P. Gattinger, Y. Zhernov, M. Khaitov, R. Valenta. DOI: https://doi.org/10.1016/j.jaci.2018.08.047.    .

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Holocene Temperatures in the Iberian Peninsula Reconstructed with Insect Subfossils

Remains of chironomid subfossils, a type of insects similar to mosquitoes, were used in a study by researchers from the University of Barcelona, the Pyrenean Ecology Institute (IPE-CSIC), and the University of Bern, to reconstruct the temperature of the Iberian Peninsula in the Holocene, the geological period that goes from 11,000 years ago until now. The results of the study prove some of the climate patterns of the Holocene brought by other methodologies: a rise of temperatures in the beginning and the end of the period, higher temperatures during the Holocene Climate Optimum and a decline of temperatures after the beginning of the Late Holocene.

 The study, published in the journal The Holocene, is the first reconstruction of the temperature of the peninsula during this period using this indicator. According to the researchers, this is a promising tool to understand the evolution of climate over history and the main natural and anthropic climate changes that shaped ecosystems before instrumental records.

Extraction of the sequence in Basa de la Mora lake by the IPE-CSIC research group of Quaternary Paleoenvironments 

Photo: Anchel Belmonte 

Participants in the study are the researcher Pol Tarrats, member of the research group Freshwater Ecology, Hydrology and Management (FEHM) of the UB and first author of the article, and the researchers Miguel Cañedo-Argüelles, Narcís Prat and Maria Rieradevall, from the same group; Blas Valero-Garcés and Penélope González-Sampériz, from the Pyrenean Institute of Ecology (IPE-CSIC), and Oliver Heiri, from the University of Bern (Switzerland).

Paleoclimate indicators in larval phase

Chironomidae are from the nematocera family (diptera order), similar to mosquitoes. These insects are abundant worldwide and change gender and amount depending on the temperature in which they live, so they are a good indicator of this climate variable. The research study was conducted in Basa de la Mora lake (Huesca), where researchers took the necessary sediments to carry the study out. “Regarding the records of Chironomidae, the aim of any paleoenvironmental reconstruction study is to get the larval cephalic capsules, since this is the larval phase of the insects that is developed in the sediments and that from which subfossil remains are obtained”, says Miguel Cañedo-Argüelles, postdoctoral researcher from the Department of Evolutionary Biology, Ecology and Environmental of the UB. Subfossils are biological remains whose fossilization process is not complete due the way these were buried in the sediment and still have organic matter which can be analysed.

These were taken by the IPE-CSIC Research Group of Quaternary Paleoenvironments to get a sequence covering the whole Holocene period. The approximation of temperatures is obtained by comparing the composition of insects taken from the sediment sample over the sequence of the study, with a calibration basis made of many samples of Chironomidae that are taken in the present which are associated with temperature changes. “In our case, we did not have that comparing element which is common in the study area (Pyrenees), so the sequence we got in Basa de la Mora lake was compared to the results of a study, the most developed and used one in Europe, conducted in 274 lakes in Switzerland and Norway”, says Pol Tarrats.

Regional differences regarding other reconstructions

The results of the study show a temperature rise in the beginning of the Holocene, reaching the highest values in the Holocene Climate Optimum (about 7,800 years ago). There are also high temperatures until about 6,000 years ago, when a decline of temperature started and led to the lowest values in the first stage of the late Holocene (about 4,200 and 2,000 years ago).

Last, researchers detected a rise of temperatures over the two last millenniums, but they state they have to be careful with these data. “We cannot guarantee the observed rise in the reconstruction results from a temperature rise only, we cannot rule out other variables that can influence at other levels, such as the gradual increase of the anthropic activity in the area, which can change the community of Chironomidae to species that adapt to higher temperatures, but there are also human influence indicators”, says Narcís Prat.

Although these conclusions can coincide with other paleoclimate reconstructions, results also highlight some divergences at a regional level. “These differences can occur due the fact that some indicators point out to different seasonal signs. Therefore, Chironomidae are indicators of temperature in summer, while others such as chrysophites or alkenones are related to winter/spring temperatures”, notes the researcher.

A tool to evaluate climate trends

Climate reconstruction of the past in general and temperatures in particular is a relevant tool when evaluating current climate trends within the context of climate change. For researchers, the methodology they use in this study is “an interesting tool to contrast, confirm and disprove patterns on evolution of temperature in the Holocene, as well as adding other indicators to reconstruct temperatures to advance in this study field”.

In this sense, the aim of the research team is to develop a comparing basis to link the present Chironomidae communities in different geographical areas of the Iberian Peninsula with temperature. “This would allow us, on the one hand, confirm the influence of temperature when explaining the distribution of different species, and on the other, to use specific transfer functions for each area, which would provide a higher precision and strength to the next studies on reconstructing temperatures out of Iberian Peninsula Chironomidae”, concludes Miguel Cañedo-Argüelles.




Contacts and sources:
University of Barcelona

Citation: “Chironomid-inferred Holocene temperature reconstruction in Basa de la Mora Lake (Central Pyrenees)” Pol Tarrats, Oliver Heiri, Blas Valero-Garcés, Miguel Cañedo-Argüelles, Narcis Prat, Maria Rieradevall, Penélope González-Sampériz. . The Holocene, 2018.
Doi: https://doi.org/10.1177/0959683618788662    .

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The Dark Ages Were Relatively Healthy or How Health Suffers When Inequality Rises

The early medieval period, from the 5th to the 10th centuries, is often called the Dark Ages. But in the age of legendary heroes such as Siegfried and King Arthur, even the middle and lower classes were healthier than their descendants in later centuries – even as late as the 19th-century industrial age. That is the conclusion reached by a team of economists, archaeologists and anthropologists who have collected data on human health in Europe over 2000 years in an unprecedented bioarchaeological survey. Their results have been published in a new book, “The Backbone of Europe - Health, Diet, Work and Violence over Two Millennia.”

Professor Jörg Baten, economic historian at the University of Tübingen, worked with Richard H. Steckel and Clark Spencer Larsen of Ohio State University and Charlotte A. Roberts from the University of Durham and numerous others to compile a vast database across a broad cross-section of European countries. To obtain an overall understanding of the history and development of human health, violence and division of labor, Baten and a team of 75 anthropologists and bioarchaeologists spent a decade examining more than 15,000 human skeletons. The remains were drawn from more than 100 different locations across Europe, and had been buried between the third century BCE and the mid-nineteenth century. The basic question was - what impact did climate and geography, as well as socio-economic developments, have on human health?

 Researchers collected data from 15,000 human remains. Damage to this skull from Schwetzingen near Heidelberg indicates a violent death
Die Wissenschaftler erhoben Daten von 15.000 menschlichen Skeletten aus mehr als 100 Regionen Europas: hier ein Schädel mit deutlich erkennbarer Hiebverletzung.
Credit: © Joachim Wahl, Landesdenkmal Amt im Regierungspräsidium Tübingen

The researchers looked at the health of the individuals’ teeth, at their stature, and evaluated various other factors concerning the quality of their diet and the apparent physical burden of their work. The researchers counted violently broken skulls and compared them with Europeans who died more peacefully. The overall data led to some surprising conclusions. For instance, it revealed that the 6th-century Plague of Justinian had indirect positive effects on the health of the population. The generations born immediately after the plague had access to a greater selection of resources, which meant better living conditions for all. Perhaps most surprisingly, the researchers found that from that point on, health overall steadily deteriorated for a long period - from the early Middle Ages to the era of industrialization. Baten and his team say this is explained by increasing population density, rising social inequality, and the Little Ice Age from the 16th to the 19th centuries.

The researchers add that the activity of states in Europe from the 15th century onward had an effect in countering the trend of poor health in the population. Government helped to increase security, which led to less violence in European societies. The study’s unique approach also enabled comparisons with comparable research conducted in the Americas. Richard H. Steckel found a similar correlation between greater social organization and higher thresholds for violence in his studies comparing pre-Colombian Mexican civilizations with the warlike tribes of North America.

The “Backbone of Europe” study helps us to better understand how economic, climate, and social change affect human health - and reinforces the imperative to learn from history.

Professor Jörg Baten heads the project B06 “Humans and Resources in the Migration Period and the Early Middle Ages. Anthropological and Bioarchaeological Analyses of the Use of Food Resources and the Detection of Migrations” jointly with Professor Jörn Staecker and Professor Joachim Wahl. It is part of the collaborative research center 1070 ResourceCultures at the University of Tübingen.


Full bibliographic information

“The Backbone of Europe - Health, Diet, Work and Violence over Two Millennia.” Richard H. Steckel, Clark Spencer Larsen, Charlotte A. Roberts, Joerg Baten (eds.). Cambridge University Press 2018The early medieval period, from the 5th to the 10th centuries, is often called the Dark Ages. But in the age of legendary heroes such as Siegfried and King Arthur, even the middle and lower classes were healthier than their descendants in later centuries – even as late as the 19th-century industrial age. That is the conclusion reached by a team of economists, archaeologists and anthropologists who have collected data on human health in Europe over 2000 years in an unprecedented bioarchaeological survey. Their results have been published in a new book, “The Backbone of Europe - Health, Diet, Work and Violence over Two Millennia.”

Professor Jörg Baten, economic historian at the University of Tübingen, worked with Richard H. Steckel and Clark Spencer Larsen of Ohio State University and Charlotte A. Roberts from the University of Durham and numerous others to compile a vast database across a broad cross-section of European countries. To obtain an overall understanding of the history and development of human health, violence and division of labor, Baten and a team of 75 anthropologists and bioarchaeologists spent a decade examining more than 15,000 human skeletons. The remains were drawn from more than 100 different locations across Europe, and had been buried between the third century BCE and the mid-nineteenth century. The basic question was - what impact did climate and geography, as well as socio-economic developments, have on human health?

File:The Plague, 1898.jpg
Credit: Wikimedia Commons

The researchers looked at the health of the individuals’ teeth, at their stature, and evaluated various other factors concerning the quality of their diet and the apparent physical burden of their work. The researchers counted violently broken skulls and compared them with Europeans who died more peacefully. The overall data led to some surprising conclusions. For instance, it revealed that the 6th-century Plague of Justinian had indirect positive effects on the health of the population. 

The generations born immediately after the plague had access to a greater selection of resources, which meant better living conditions for all. Perhaps most surprisingly, the researchers found that from that point on, health overall steadily deteriorated for a long period - from the early Middle Ages to the era of industrialization. Baten and his team say this is explained by increasing population density, rising social inequality, and the Little Ice Age from the 16th to the 19th centuries.

The researchers add that the activity of states in Europe from the 15th century onward had an effect in countering the trend of poor health in the population. Government helped to increase security, which led to less violence in European societies. The study’s unique approach also enabled comparisons with comparable research conducted in the Americas. Richard H. Steckel found a similar correlation between greater social organization and higher thresholds for violence in his studies comparing pre-Colombian Mexican civilizations with the warlike tribes of North America.

The “Backbone of Europe” study helps us to better understand how economic, climate, and social change affect human health - and reinforces the imperative to learn from history.

Professor Jörg Baten heads the project B06 “Humans and Resources in the Migration Period and the Early Middle Ages. Anthropological and Bioarchaeological Analyses of the Use of Food Resources and the Detection of Migrations” jointly with Professor Jörn Staecker and Professor Joachim Wahl. It is part of the collaborative research center 1070 ResourceCultures at the University of Tübingen.



Contacts and sources:
University of Tübingen

Citation:  “The Backbone of Europe - Health, Diet, Work and Violence over Two Millennia.” Richard H. Steckel, Clark Spencer Larsen, Charlotte A. Roberts, Joerg Baten (eds.). Cambridge University Press 2018
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New Thermography Tech Catches Liars Using "Pinocchio Effect" - More Accurate than Polygraph

Scientists from the University of Granada have studied the so‑called ‘Pinocchio Effect’, which causes the temperature of the nose to decrease between 0.6 ºC and 1.2 ºC while that of the forehead increases between 0.6 ºC and 1.5 ºC when a person is lying

The new method for detecting lies in a laboratory is more accurate and yields less false positives than a polygraph: it offers an accuracy of up to 80% and 20% of false positives.

Researchers from the University of Granada (UGR) have designed the most accurate laboratory model to date for determining if a person is lying or telling the truth. This method, which uses thermography techniques, is based on the so‑called ‘Pinocchio Effect’: when a person is lying, the temperature of the nose decreases while that of the forehead increases, among other facial thermal changes.

The researchers, belonging to the UGR Mind, Brain, and Behavior Research Center (CIMCYC, from its name in Spanish), point out that this system is more accurate than the famous polygraph –a measuring instrument used for recording physiological responses– and other brain‑imaging techniques used in research, since thermography offers an accuracy of up to 80% (10% higher than that of the polygraph).

Two thermal images corresponding to the beginning and the end of the lie: the decrease in the temperature of nose and hands and the increase in the temperature of the forehead are noticeable
Credit: University of Granada

Emilio Gómez Milán, lead researcher of this study, points out that the two facial regions key for measuring this ‘Pinocchio Effect’ are the forehead and the tip of the nose. “When we lie, the temperature of the tip of the nose decreases between 0.6 ºC and 1.2 ºC, while that of the forehead increases between 0.6 ºC and 1.5 ºC. The greater the difference in temperature between both facial regions, the more likely the person is lying,” the expert points out.

The reason for this phenomenon to occur is quite simple. When someone lies, the body experiences an emotional response, anxiety, which is revealed in the temperature of the nose. “Besides, a cognitive response also occurs since, for lying, we have to think, to plan our excuses, to analyze the context…, and that causes a cognitive charge in us, a strong demand for attentional control which translates into an increase in the temperature of the forehead,” Gómez Milán explains.

One of the subjects participating in the study makes a phone call lying to the person at the other end of the line. In the thermal image, the temperature of the nose has decreased while that of the forehead has increased
Credit: University of Granada

In other words, according to the author, “one has to think in order to lie, which rises the temperature of the forehead; but at the same time we feel anxious, which lowers the temperature of the nose.”

The UGR researcher warns that it is necessary to differentiate between the study of lying in a laboratory and in real life. “The methods we use in the laboratory are very different of those used, for example, by the Police, which uses the so‑called strategic interviewing (with questionnaires including ‘tricky’ questions and demanding a lot of details) to try and catch a liar.” True detection of lies, even carried out by professionals, is only slightly higher than pure chance (54%), and the rate rises to 60%‑70% with strategic interviewing.Its use in airports and refugee camps

“The ideal case would be to combine both methods, strategic interviewing and thermography, moving our system to, for example, police stations, airports or refugee camps. That way, it would be possible to detect if a criminal is lying or to know the true intentions of people trying to cross the border between two countries,” Gómez Milán says.

In order to carry out this study, published in theJournal of Investigative Psychology and Offender Profiling, the researchers worked with a sample of 60 Psychology students from the University of Granada, who underwent a series of tasks with the thermographer.

One of those tasks was to make a telephone call of about 3 to 4 minutes to a close person (partner, mother, friend, etc.), in which they should tell a significant lie made up by themselves (e.g., that they saw a celebrity or that they had had a car accident).

On the other hand, the control group, also monitored by the thermal camera, would make a similar call, but telling to the person at the other end of the line what they were watching on the computer (that is, gross images of mutilated bodies and car accidents).

Emilio Gómez Milán, UGR researcher

Credit: University of Granada

“In both cases, the circumstances made them feel anxious, but the experimental group experienced the so‑called ‘Pinocchio Effect’ in the nose and the effect of ‘mental effort’ in the forehead, which allowed us to monitor the lie,” the researcher explains.

The author warns that, despite the fact that this new method for detecting lies is an improvement on existing ones, “there’s no method with an accuracy of 100%, since the difference between truth and lie is quantitative, not qualitative. However, with this method we have achieved to increase accuracy and reduce the occurrence of ‘false positives’, something that is frequent with other methods such as the polygraph.”







Contacts and sources:
University of Granada

Citation:   The Mental Nose and The Pinocchio Effect: Thermography, planning, anxiety and lies
Moliné, E. Dominguez, E. Salazar‐López, G. Gálvez‐García, J. Fernández‐Gómez, J. De la Fuente, O. Iborra, F.J. Tornay, E. Gómez Milán
Journal of Investigative Psychology and Offender Profiling, Volumen 15, Issue 2, 2018.
DOI: https://doi.org/10.1002/jip.1505   .

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Sunday, November 11, 2018

Scientists Capture the Sound of Sunrise on Mars


Academics transform photo of landmark Mars sunrise into a piece of music

Scientists have created the soundtrack of the 5,000th Mars sunrise captured by the robotic exploration rover, Opportunity, using data sonification techniques to create a two-minute piece of music.

Researchers created the piece of music by scanning a picture from left to right, pixel by pixel, and looking at brightness and colour information and combining them with terrain elevation. They used algorithms to assign each element a specific pitch and melody. 

An image of the 5,000th sunrise captured by the Mars rover, Opportunity
Credit: NASA

The quiet, slow harmonies are a consequence of the dark background and the brighter, higher pitched sounds towards the middle of the piece are created by the sonification of the bright sun disk.

Credit: Anglia Ruskin University

Dr Domenico Vicinanza, of Anglia Ruskin University, and Dr Genevieve Williams, of the University of Exeter, will present the world premiere of the piece, entitled Mars Soundscapes in the NASA booth at the forthcoming Supercomputing SC18 Conference in Dallas (13 November).

The piece will be presented using both conventional speakers and vibrational transducers so the audience could feel the vibrations with their hands, thus enjoying a first-person experience of a sunrise on Mars.

Opportunity is a robotic rover that has been providing photographic data on Mars for NASA since 2004. Earlier this year, it ceased communications following a dust storm. Scientists hope that it may resume its function later this year.

Dr Vicinanza, Director of the Sound and Game Engineering (SAGE) research group at Anglia Ruskin, said: “We are absolutely thrilled about presenting this work about such a fascinating planet.

“Image sonification is a really flexible technique to explore science and it can be used in several domains, from studying certain characteristics of planet surfaces and atmospheres, to analysing weather changes or detecting volcanic eruptions.

“In health science, it can provide scientists with new methods to analyse the occurrence of certain shapes and colours, which is particularly useful in image diagnostics.”


Contacts and sources:
Jamie ForsythAnglia Ruskin University



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Researchers Uncover Evidence of Restored Vision in Rats Following Cell Transplant

Researchers from the University of California, Irvine School of Medicine, have discovered that neurons located in the vision centers of the brains of blind rats functioned normally following fetal retina cell transplants, indicating the successful restoration of vision. The research was published today in JNeurosci, the Journal of Neuroscience.

Led by David Lyon, PhD, associate professor of Anatomy & Neurobiology and director of graduate studies at the UCI School of Medicine, the study, titled, “Detailed visual cortical responses generated by retinal sheet transplants in rats with severe retinal degeneration,” reveals that sheets of fetal cells integrate into the retina and generate nearly normal visual activity in the brains of blind rats. 

The left side of the figure illustrates the retina transplantation procedure. The right side of the figure represents examples of orientation tuning curves recorded from three rats: a normal rat, a rat with a transplant and a rat with a degenerated retina (blind). Displayed below the tuning curves are the responses to sinusoidal grating stimuli. The response patterns indicate that neurons in the brains of transplant recipients are very similar to those of the rats with normal vision.
  ALT text
Credit: UCI School of Medicine

”It’s been known that retinal sheet transplants can integrate into the degenerated eyes and allow the animals to detect light. But, beyond rudimentary light detection it was not known how well the visual system in the brain functioned with the newly integrated retinal transplant,” said Lyon. “In this study, we found that neurons in the primary visual processing center perform as well as neurons in animals with normal healthy retinas. These results show the great potential of retinal transplants to treat retinal degeneration in people.”

Age-related macular degeneration and retinitis pigmentosa lead to profound vision loss in millions of people worldwide. Degeneration of the retina as a result of age or progressive eye disease damages the light-detecting cells necessary for accurate vision. Current treatments can only help protect existing cells from further damage and are ineffective during late stages of disease once these cells are gone. Retinal sheet transplants have been successful in animal and human studies, but their ability to restore complex vision has not yet been assessed.

“Remarkably, we found fetal retinal sheet transplants generated visual responses in cortex similar in quality to normal rats. The transplants also preserved connectivity within the brain that supports potential of this approach in curing vision loss associated with retinal degeneration,” said Lyon.

Measuring the response of neurons in the primary visual cortex, Lyon and colleagues demonstrated how rats with severe retinal degeneration that received donor cells became sensitive to various attributes of visual stimuli, including size, orientation, and contrast, as early as three months following surgery. The study represents an important step forward in combating age- and disease-related vision loss in human adults. Follow up behavioral research will be necessary to further determine effectiveness and acuity.


Contacts and sources:
University of California - Irvine


Citation: Detailed visual cortical responses generated by retinal sheet transplants in rats with severe retinal degeneration.
Andrzej T. Foik, Georgina A. Lean, Leo R. Scholl, Bryce T. McLelland, Anuradha Mathur, Robert B. Aramant, Magdalene J. Seiler, David C. Lyon. The Journal of Neuroscience, 2018; 1279-18 DOI: 10.1523/JNEUROSCI.1279-18.2018  
http://www.jneurosci.org/content/early/2018/11/05/JNEUROSCI.1279-18.2018 .

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Fossil Soft Tissue In Dinosaur Bones and Burnt Toast


Burnt toast and dinosaur bones have a common trait, according to a new, Yale-led study. They both contain chemicals that, under the right conditions, transform original proteins into something new. It's a process that may help researchers understand how soft-tissue cells inside dinosaur bones can survive for hundreds of millions of years.

A research team from Yale, the American Museum of Natural History, the University of Brussels, and the University of Bonn announced the discovery Nov. 9 in the journal Nature Communications.

Fossil soft tissue in dinosaur bones has been a controversial topic among researchers for quite some time. Hard tissues, such as bones, eggs, teeth, and enamel scales, are able to survive fossilization extremely well. Soft tissues, such as blood vessels, cells, and nerves -- which are stored inside the hard tissue -- are more delicate and thought to decay rapidly after death. These soft tissues are composed mainly of proteins, which are believed to completely degrade within about four million years.

Dinosaur blood vessel with adjacent bone matrix that still contains bone cells. These structures have a perfect morphological preservation over hundreds of millions of years, but are chemically transformed through oxidative crosslinking. The extract comes from a sauropod dinosaur.

Credit: Jasmina Wiemann/Yale University


Yet dinosaur bones are much older, roughly 100 million years old, and they occasionally preserve organic structures similar to cells and blood vessels. Various attempts to resolve this paradox have failed to provide a conclusive answer.

"We took on the challenge of understanding protein fossilization," said Yale paleontologist Jasmina Wiemann, the study's lead author. "We tested 35 samples of fossil bones, eggshells, and teeth to learn whether they preserve proteinaceous soft tissues, find out their chemical composition, and determine under what conditions they were able to survive for millions of years."

The researchers discovered that soft tissues are preserved in samples from oxidative environments such as sandstones and shallow, marine limestones. The soft tissues were transformed into Advanced Glycoxidation and Lipoxidation end products (AGEs and ALEs), which are resistant to decay and degradation. They're also structurally comparable to chemical compounds that stain the dark crust on toast.



Experimental maturation initiates glycoxidation/lipoxidation in a fresh eggshell matrix sample. The local browning of the otherwise translucent sample represents the formation of N-heterocyclic polymers.

Credit: Jasmina Wiemann/Yale University


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AGEs and ALEs are characterized by a brownish color that stains fossil bones and teeth that contain them. The compounds are hydrophobic, which means they are resistant to the normal effects of water, and have properties that make it difficult for bacteria to consume them.

Wiemann and her colleagues made their discovery by decalcifying fossils and imaging the released soft tissue structures. They applied Raman microspectroscopy -- a non-destructive method for analyzing both the inorganic and organic contents of a sample -- to the extracted fossil soft tissues. During this process, laser energy directed at the tissue causes molecular vibrations that carry spectral fingerprints for the chemicals that are present.

Co-author Derek Briggs, Yale's G. Evelyn Hutchinson Professor of Geology and Geophysics and a curator at the Yale Peabody Museum of Natural History, said the study points to localities where soft tissue may be found in fossil bones, including sandstones deposited from rivers, dune sands, and shallow marine limestones.

"Our results show how chemical alteration explains the fossilization of these soft tissues and identifies the types of environment where this process occurs," Briggs said. "The payoff is a way of targeting settings in the field where this preservation is likely to occur, expanding an important source of evidence of the biology and ecology of ancient vertebrates."

Additional co-authors of the study are Matteo Fabbri from Yale, Martin Sander and Tzu-Ruei Yang from the University of Bonn, Koen Stein from the University of Brussels, and Mark Norell from the American Museum of Natural History.
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Contacts and sources:
Jim Shelton
Yale University


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Saturday, November 10, 2018

Aspirin Does It Really Help Your Heart?



Many people think taking one aspirin every morning can help prevent a heart attack or stroke. However, studies are questioning this one-size-fits-all approach.

 Furthermore, a recent study suggests that taking aspirin strictly for heart attack or stroke prevention does not offer any benefits to those over 65 and otherwise healthy.

Sandeep Nathan, MD, MS, associate professor of medicine and director of the coronary care unit at the University of Chicago Medicine, offered his thoughts on prescribing aspirin.

According to Nathan, the current approach is popular because that’s where the data previously pointed. However, the new data begs a couple of important questions.

Side effects of aspirin.png
Credit: Mikael Häggström / Wikimedia Commons

“Number one, does aspirin even work at all? Number two, what is the right dose of aspirin? Number three, does aspirin do what it says it will do in terms of reduction of cardiovascular events within an acceptable safety boundary?” said Nathan.

To answer the first question, yes, aspirin does work. The other two answers, however, are not so cut and dried.

“The proper dosing of aspirin is still to be determined,” said Nathan. “What we do know is that very low doses of aspirin are enough to inhibit the stickiness of blood platelets which we believe is the primary mechanism of benefit from a cardiovascular or cerebrovascular event standpoint.”

Very low doses, meaning 40 to 50 milligrams of aspirin, will help prevent blood platelets from sticking in laboratory experiments. People often refer to this as thinning of the blood to prevent clotting. Nathan notes that the original dosing regimen of aspirin is loosely derived from an antiquated system that dates back more than 1,000 years – so it’s no surprise it’s due for a change.

If 40 or 50 milligrams will probably do the trick, why do we commonly see people popping much larger doses?

“High doses of aspirin are associated with GI irritation and perhaps even bleeding from the stomach whereas low doses may be clinically ineffective,” said Nathan. “So the sweet spot is somewhere in between, but it floats based on a patient’s characteristics and size.”

A high dose of aspirin can be thought of as consuming anything above 325 mg on a daily basis, which again can be risky for patients 65 and older.

“The older you get, the higher your likelihood of cardiovascular events that are in large part, ascribable to blood clotting,” said Nathan. “But at the same time your risk of bleeding goes up.”

According to Nathan, the question of whether aspirin is more trouble than it is worth seems to go back to calculating the proper dose.

“I don’t think aspirin is killing people. We need to recalibrate our risk assessment tools and every patient decision needs to be an individual decision,” said Nathan. “I would discourage anyone from making broad generalizations about aspirin. In the future we will become more finessed in deciding which patients ought to be on aspirin and finding the right dose.”

Aside from taking aspirin, a healthy diet, a reasonable body mass index and cholesterol reduction are some of the easiest ways to avoid heart disease.



Contacts and sources
Jordan Porter-Woodruff
University of Chicago Medicine
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Ancient DNA Evidence Reveals Two Unknown Migrations from North to South America



An international research team has used genome-wide ancient DNA data to revise Central and South American history. Their analysis of DNA from 49 individuals spanning about 10,000 years in Belize, Brazil, the Central Andes, and southern South America has concluded that the majority of Central and South American ancestry arrived from at least three different streams of people entering from North America, all arising from one ancestral lineage of migrants who crossed the Bering Strait some time before 15,000 years ago.

The evidence, presented November 8 in the journal Cell, shows that within this one ancestral lineage, there were two previously undocumented streams of gene flow from North to South America, one of which was later displaced in a major population replacement that began at least 9,000 years ago.

This visual abstract depicts the findings of Posth et al., who conducted a large-scale analysis of ancient genomes from Central and South America yields insights into the peopling of the Americas, including four southward migration events and notable population continuity in much of South America after arrival.

Credit: Posth et al./Cell

"Our work multiplied the number of ancient genomes available from these areas by about 20, giving us a much more comprehensive picture of indigenous history in the Americas," says co-senior author David Reich, a geneticist at Harvard Medical School and the Howard Hughes Medical Institute. "This broader dataset reveals a common origin of North, Central, and South Americans as well as two previously unknown genetic exchanges between North and South America."

"Nearly all Central and South Americans arose from a star-like radiation of the first lineage into at least three branches," says co-lead author Cosimo Posth, an archaeogeneticist from the Max Planck Institute for the Science of Human History. "That means that nearly all the ancestry of Central and South Americans came from the same source population, albeit one that had already diversified prior to its spread into South America. With DNA evidence largely based on present-day people, those multiple gene flow events are undetectable, highlighting the power of ancient DNA data."

The genome analysis also yielded new insights on the Clovis culture-related people, who were mainly distributed across North America from about 13,000 years ago. Archaeological evidence from Clovis sites shows that the spread of Clovis artefacts did not expand throughout South America. But when the researchers used genome-sequencing technology to generate and compare genomes from a previously published ~13,000-year-old Clovis-related genome in Montana to the earliest genomes analyzed from South and Central America dating to between ~9,000 and ~11,000 years ago, they noticed significant shared ancestry. That suggested that the people who spread the Clovis culture also left a major impact much father south through people producing non-Clovis-specific stone tools.

"We weren't expecting to find a relation to people associated with the Clovis culture in South America," says co-first author Nathan Nakatsuka, a PhD student in Reich's lab at Harvard. "But it seems the expansion of the Clovis-associated lineage extended to parts of Central and South America."

The paper concludes that this Clovis-related lineage contributed substantially to a group of 9,000-10,000-year-old individuals from Lagoa Santa in Brazil, inconsistent with the hypothesis that the people from this site derived from a separate migration from Asia. The authors also detected the Clovis-related genetic affinity in an even older, almost ~11,000-year-old individual from Chile and a slightly younger, more than ~9,000-year-old individual from Belize.

Beginning around ~9,000 years ago with ancient samples in Peru, however, the authors detected an almost complete disappearance of the Clovis culture-associated ancestry in Central and South America, documenting a remarkable population replacement. The large-scale population replacement is a process that was not widely expected by archaeologists," says Reich. "This is an exciting example of how ancient DNA studies can reveal events in the past that were not confirmed and thus can stimulate new work in archaeology."

The researchers also showed that after this major population turnover, there was striking continuity compared to other parts of the world like Eurasia and Africa. "There is remarkable continuity between earlier and later skeletons with South Americans today," says Posth. "For example, modern-day Quechua and Aymara from the Central Andes can trace their ancestry back to the ancient people of the Cuncaicha site from 9,000 years ago onwards. This is a longer-standing continuity than you see in other continents."

The researchers recognize that there is much more work to do to fully flesh out the history of the Americas.

"We're very enthusiastic about the prospects for a much richer understanding of American population history, but this is still a vast region full of geographic and chronological holes," says Reich. "We'd like to collect more genetic material from earlier and later sites and from more countries, such as Colombia, Venezuela, and other parts of Brazil. We also want to examine the evolution of genetic traits over time."


This research was funded by the NIH, the Wenner-Gren Foundation, the Hellman Foundation, the U.S. National Science Foundation, the Howard Hughes Medical Institute, the Programa FONDECYT Regional, the National Geographic Society, the Agencia Nacional de Promoción Científica y Técnica, the Consejo Nacional de Investigaciones Científicas y Técnicas, the Australian Research Council, the he Environment Institute at Adelaide University, the National Science Foundation, the Alphawood Foundation, the Alexander von Humboldt Foundation, the Max Planck Institute-Jena, the DFG Center for Advanced Studies, the Pontifical Catholic University of Lima, Northern Illinois University, the Deutsche Forschungsgemeinschaft, the National Research Council of Argentina, FAPESP, and the Allen Discovery Center.






Contacts and sources:
\Erin Kohnke
Cell Press

Citation:   Cell, Posth et al.: "Reconstructing the Deep Population History of Central and South America" https://www.cell.com/cell/fulltext/S0092-8674(18)31380-1   .

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Adaptations to Harsh Environment Spared Andean Highlanders from Complete Devastation Due to European Contact

Adaptations to the harsh environment spared Andean highlanders from complete devastation due to European contact. The Andean highlands of South America have long been considered a natural laboratory for the study of genetic adaptation of humans.

A multi-center study of the genetic remains of people who settled thousands of years ago in the Andes Mountains of South America reveals a complex picture of human adaptation from early settlement, to a split about 9,000 years ago between high and lowland populations, to the devastating exposure to European disease in the 16th-century colonial period.

Led by Anna Di Rienzo, PhD, and John Lindo, PhD, JD, from the University of Chicago; Mark Aldenderfer, PhD, from the University of California, Merced; and Ricardo Verdugo from the University of Chile, the researchers used newly available samples of DNA from seven whole genomes to study how ancient Andean people--including groups that clustered around Lake Titicaca in Peru and Bolivia, 12,000 feet above sea level--adapted to their environment over the centuries.

This is the location of ancient samples near Lake Titicaca, elevation 3812 meters, in what is now Peru and Bolivia.

Credit: Authors of the study

In the journal Science Advances, they compared their seven historical genomes to 64 modern-day genomes from a current highland Andean population, the agropastoral Aymara of Bolivia, and the lowland hunter-gatherer Huilliche-Pehuenche in coastal Chile.

The goals were (1) to date the initial migration to the Andean highlands, (2) to identify the genetic adaptations to the high-altitude environment that allowed that settlement, (3) to estimate the impact of the European contact starting in the 1530s that caused the near annihilation of many lowland communities of South America.

"We have very ancient samples from the high Andes," said Di Rienzo. "Those early settlers have the closest affinity to the people who now live in that area. This is a harsh, cold, resource-poor environment, with low oxygen levels, but people there adapted to that habitat and the agrarian lifestyle."

The study, "The Genetic prehistory of the Andean highlands 7,000 years BP through European contact," uncovered several unexpected features.

A traditional Aymara ceremony in Copacabana, on the border of Lake Titicaca in Bolivia. 
Aymara ceremony
Image from Wikimedia Commons

The researchers found that highland Andeans experienced much smaller than expected population declines following contact with European explorers who first came to South America in the 1530s. In the lowlands, demographic modeling and historical records infer that up to 90 percent of residents may have been wiped-out after the arrival of Europeans. But the people living in the upper Andes had only a 27-percent population reduction.

The high Andes are a harsh, cold, resource-poor environment, with low oxygen levels, but the people there adapted to that habitat and the agrarian lifestyle.

Even though the highlanders lived in altitudes above 8,000 feet, which meant reduced oxygen, frequent frigid temperatures and intense ultra-violet radiation, they did not develop the responses to hypoxia seen in natives of other high-altitude settings, such as Tibet.

The Andeans may have adapted to high altitude hypoxia "in a different way, via cardiovascular modifications," the researchers suggest. They found evidence of alterations in a gene called DST, which is associated with the formation of cardiac muscle. Andean highlanders tend to have enlarged right ventricles. This may have improved oxygen intake, enhancing blood flow to the lungs.

But the strongest adaptation signal the researchers found was in a gene called MGAM (maltase-glucoamylase) an intestinal enzyme. It plays an important role in the digestion of starchy foods such as potatoes--a food native to the Andes. A recent study suggests that the potato may have been domesticated in the region at least 5,000 years ago. Positive selection on the MGAM gene, the authors note, "may represent an adaptive response to greater reliance upon starchy domesticates."

Time Line: the Prehistory of the Andean Highlands: Demography-Entry into the Americas 20 ka ago. High/low altitude split 8750 years. European contact 1532 AD

Credit: Authors of the study

The early presence of this variant in Andean peoples suggests "a significant shift in diet from one that was likely more meat based to one more plant based," said UC Merced's Aldenderfer, an anthropologist. "The timing of the appearance of the variant is quite consistent with what we know of the paleo-ethno-botanical record in the highlands."

Although Andean settlers consumed a high-starch diet after they started to farm, their genomes did not develop additional copies of the starch related amylase gene, commonly seen in European farming populations.

A comparison of the ancient genomes with their living descendants also revealed selection for immune-related genes soon after the arrival of Europeans, suggesting that Andeans who survived may have had an advantage with regard to the newly introduced European pathogens.


Anna Di Rienzo, University of Chicago Medical Center

Credit: Study authors

"Contact with Europeans had a devastating impact on South American populations, such as the introduction of disease, war, and social disruption," explained Lindo. "By focusing on the period before that, we were able to distinguish environmental adaptations from adaptations that stemmed from historical events."

"In our paper," said Aldenderfer, "there was none of this prioritization of genes at the expense of archaeological data. We worked back and forth, genetics and archeology, to create a narrative consistent with all of the data at hand."


Contacts and sources:
John Easton
University of Chicago Medical Center



Citation: The genetic prehistory of the Andean highlands 7000 years BP though European contact http://dx.doi.org/10.1126/sciadv.aau4921

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66,000 Years Ago Stone Tools Connected Communities 300 Km Apart

Stone tools from the Middle Stone Age in South Africa shows that different communities were connected over long time periods over vast geographical areas.

Stone tools that were discovered and examined by a group of international experts showed for the first time that various communities that lived during the Middle Stone Age period were widely connected and shared ideas around tool design.

The tools – mainly blades and backed knives from the Howiesons Poort – were found in various layers in the Klipdrift Shelter, in the southern Cape in South Africa. They were examined by a group of lithic experts, who found distinct similarities to tools from sites in South Africa’s Western Cape, over 300km away, in particular with the Diepkloof Rock Shelter site.

This is an overview of the Klipdrift Complex from sea.

Credit: Magnus Haaland

“While regional specificities in the tools from the various sites exist, the similarities of Klipdrift Shelter with the site of Diepkloof Rock Shelter are astonishing,” says Dr Katja Douze, the corresponding author of the study that was published in PlosOne on November 7.

 Douze is a researcher at the laboratory of Archaeology and Populations in Africa at the University of Geneva, Switzerland. Douze was a post-doctoral fellow at the Center of Excellence in Palaeosciences at the Evolutionary Studies Institute, at University of the Witwatersrand (Wits), at the time of the study. She led the analysis together with Dr Anne Delagnes, Research Director at the French National Center for Research (CNRS) and director of the laboratory PACEA, at the University of Bordeaux, and with Dr Sarah Wurz, Associate professor at the School of Geography, Archaeology and Environmental Sciences, University of the Witwatersrand and also associated with the DST/NRF SARChI Chair in The Origins of Modern Human Behaviour and the SapienCE - Centre for Early Sapiens Behaviour (SFF CoE).

The team, under the leadership of Professor Christopher Henshilwood from Wits University and the University of Bergen’s SapienCE Centre for Early Sapiens Behaviour, examined thousands of stone tools that were excavated from seven layers that represent a time period of between 66 000 years ago and 59 000 years ago, to establish the differences in stone tool design over time. They then also compared the stone tools to various other sites in Howiesons Poort.

“The site of Klipdfrift Shelter is one of the few containing a long archaeological sequence that provides data on cultural changes over time during the Howiesons Poort,” says Douze. “This makes it perfect to study the change in culture over time.”

These are examples of Howiesons Poort stone tools from Klipdrift.

Credit: Anne Delagnes and Gauthier Devilder

However, what was even more exciting for the researchers was the fact that for the first time they could show closely networked interaction between distant communities through the way they designed stone tools.

“There was an almost perfect match between the tools from the Klipdrift and Diepkloof shelters,” says Douze. “This shows us that there was regular interaction between these two communities.”

“This is the first time that we can draw such a parallel between different sites based on robust sets of data, and show that there was mobility between the two sites. This is unique for the Middle Stone Age,” says Douze.

The Middle Stone Age in Africa stretches from 350 000 years ago to 25 000 years ago and is a key period for understanding the development of the first Homo sapiens, their behavioral changes through time and their movements in-and-out of Africa.

Named after Howieson’s Poort Shelter archeological site near Grahamstown in South Africa, the Howiesons Poort is a specific techno-culture within the Middle Stone Age that evolves in southern Africa after 100 000 years ago at the Diepkloof Shelter, but between 66 000 – 59 000 years at most other Howiesons Poort sites. The characteristics of the Howiesons Poort are strongly distinctive from other Middle Stone Age industries as it is characterised by the production of small blades and backed tools, used as hunting armatures as much as for cutting flesh, while other MSA industries show flake, large blade and point productions.

The tools found in the deeper layers of the Klipdrift Shelter that represent the earlier phases of the Howiesons Poort were found to be made from heat-treated silcrete, while those from later phases were made from less homogeneous rocks such as quartz and quartzite. his change happens together with changes in tool production strategies. “The changes over time seems to reflect cultural changes, rather than immediate alterations forced on the designers by changes in climate”, says Douze.

This is the location of the Klipdrift Shelter and other South African Howiesons Poort sites

Credit: Katja Douze


“Our preconceived idea of prehistoric groups is that they just struggled to survive, but in fact they were very adaptable to environmental circumstances. There seem to be no synchrony between modification in design choices and environmental changes. However, the aridification of the area over time might have led to a very gradual change that led to the end of the Howiesons Poort.”

The team also attempted to establish why and how the Howiesons Poort ended, and to see whether it came to a sudden, or gradual end.

“The decline of the Howiesons Poort at Klipdrift Shelter shows a gradual and complex pattern of changes, from which the first “symptoms” can be observed much earlier than the final abandonment of typical Howiesons Poort technology and toolkits,” says Douze.

“This does not support a catastrophic scenario involving alarming demographic drops or massive population replacements. The fact that a similar pattern of gradual change has been described for at least three other southern African Howiesons Poort sites (Rose Cottage Cave, Diepkloof Rock Shelter and Klasies River main site), further ascertains convergent evolutions in cultural trajectories rather than isolated groups promptly reacting to locally determined pressures.”





Contacts and sources:
Sarah Wurz
University of Witwatersrand  (Wits University)


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Discovery of Ancient Ancestry Linking the Americas: Two Previously Unknown Genetic Exchanges Between North and South America



The first high quality ancient DNA data from Central and South America—49 individuals some as old as 11,000 years—has revealed a major and previously unknown exchanges between populations.

Unprecedented details about the ancestry of the people of Central and South America have been uncovered in a new study in the journal Cell by archaeologists and geneticists at The University of New Mexico, Harvard Medical School, the Howard Hughes Medical Institute, the Max Planck Institute for the Science of Human History, the University of California Santa Cruz, the Pennsylvania State University, the University of São Paulo, and other institutions in Brazil, Belize, Chile, Argentina, Peru, the European Union and the U.S.

The researchers analyzed DNA data from precisely dated skeletons found in excavations in Central and South America. Some of these people were over 10,000 years old. Previously, the only genomes that had been reported from this region and that provided sufficient quality data to analyze were less than 1,000 years old. 

Graphic showing the geographic movement of populations discussed in the study.
Graphic Credit : Michelle O'Reilly; Posth, Nakatsuka et al. 2018. Reconstructing the Deep Population History of Central and South America. Cell. 

After obtaining official permits to excavate, the researchers conducted analysis on ancient human remains, and consulted with local governmental agencies and indigenous organizations.

By comparing ancient and modern genomes from the Americas and other parts of the globe, they were able to obtain qualitatively new insights into the early history of Central and South America.

UNM Anthropology Professor Keith Prufer and his colleagues from Pennsylvania State and Exeter University (UK) contributed the Central American component of this unprecedented study as part of an NSF and Alphawood Foundation funded project studying the earliest humans to settle in the American tropics.

Prufer led excavations in Belize where the they recovered three of the oldest skeletons from the region, all with well-preserved DNA.

This UNM project focuses on early human adaptations in remote tropical rainforests in the Americas. The data from these excavations are reshaping how researchers view Early Holocene relationships between humans living in North, Central and South America.

Link between a Clovis culture-associated individual and the oldest Central and South Americans

Excavation in progress at the rock shelter site of Lapa do Santo in Brazil, where an individual dating to approximately ~9,600 years ago was found. 
Credit:  André Strauss


“A key discovery was that a Clovis culture-associated individual from North America dating to around 12,800 years ago shares distinctive ancestry with the oldest Chilean, Brazilian and Belizean individuals,” explains co-lead author Cosimo Posth of the Max Planck Institute for the Science of Human History. “This supports the hypothesis that the expansion of people who spread the Clovis culture in North America also reached Central and South America.”

These individuals from Chile, Brazil and Belize date to more than 9,000 years ago. However, younger individuals and present-day people in South America do not share the Clovis culture-associated ancestry that characterizes the oldest individuals. Says co-senior author David Reich from Harvard Medical School and the Howard Hughes Medical Institute, “This is our second key discovery: we have shown that there was a continent-wide population replacement that began at least 9,000 years ago.”

According to Prufer, there are many remarkable aspects to this research finding.

“For the first time, we have archaeological and genetic evidence linking some of the oldest humans in Central America to the earliest known populations to arrive in the New World, and clear indications of an early relationship between this region and South America,” says Prufer. “It is also a testament to the power of interdisciplinary research involving archaeologists and geneticists and how it is revolutionizing the study of ancient humans.”

The promise of ancient DNA research in the Americas

The researchers emphasize that their study gives only a glimpse of the discoveries that may come through future work. To learn about the initial movements of people into Central and South America, it would be necessary to obtain ancient DNA from individuals dating to before 11,000 years ago.

Additionally, even for the period between 11,000 and 3,000 years ago that is best covered in this study the picture is far from complete. 

Where two, 7,400 year old indiivduals were found. 
Credit: Keith Prufer, Bladen Paleoindian and Archaic Archaeological Project


“We lacked ancient data from Amazonia, northern South America and the Caribbean, and thus cannot determine how individuals in these regions relate to the ones we analyzed,” explains Reich. “Filling in these gaps should be a priority for future work.”

“We are excited about the potential of research in this area,” states co-senior author Johannes Krause of the Max Planck Institute for the Science of Human History. “With future, regionally focused studies with large sample sizes, we could realize the potential of ancient DNA to reveal how the human diversity of this region came to be the way it is today.”\


Contacts and sources:
Katie WilliamsThe University of New Mexico



Citation: Reconstructing the Deep Population History of Central and South America
.http://dx.doi.org/10.1016/j.cell.2018.10.027

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