Surprisingly mature galaxies in the early Universe

CNRS

Research News

 

IMAGE: ARTIST'S ILLUSTRATION OF A DUSTY, ROTATING DISTANT GALAXY, IN THE EARLY UNIVERSE. IN THIS IMAGE, THE RED COLOR REPRESENTS GAS, AND BLUE/BROWN REPRESENTS DUST AS SEEN IN RADIO WAVES WITH... view more 

CREDIT: © B. SAXTON NRAO/AUI/NSF, ESO, NASA/STSCI; NAOJ/SUBARU

When the Universe was only a tenth of its current age its galaxies experienced a growth spurt. It was this period that the scientists in the ALPINE project (1) focused on when they used ESO's ALMA (2) telescope to carry out the first ever large survey of distant galaxies. To their surprise, these galaxies observed in the early stages of their life were far more mature than expected. Their work is the subject of a series of articles published on 27 October 2020 in the journal Astronomy & Astrophysics, signed among others by members of the CNRS and Aix-Marseille Université (3).

Galaxies began to form very early in the history of the Universe. To study their infancy, it is therefore necessary to go back to the dawn of time, by observing very distant galaxies. The ALPINE project focused on a period between 1 and 1.5 billion years after the Big Bang, when the first galaxies experienced a phase of rapid growth. Although such distant galaxies have already been observed, this is the first time that so many of them have been studied systematically. Images of 118 massive (4) galaxies, obtained with the Hubble (visible light) and Spitzer (near infrared) space telescopes, as well as spectra acquired using the ground-based VLT and Keck telescopes, were supplemented by 70 hours of observation with ALMA at submillimetre wavelengths (between the infrared and radio waves).

ALMA can quantify dust, a sign of maturity in galaxies, and cold gas, which provides information about their rate of growth and the number of stars they can form, as well as the motion of this gas, thus revealing the dynamics of galaxies. And this turned up some surprising data. For a start, the observed galaxies proved to be very rich not only in cold gas, which fuels star formation, but also in dust, which is thought to be a by-product of stars at the end of their lives. So despite their young age, these galaxies had apparently seen the formation and death of a first generation of stars! The galaxies surveyed also exhibit an astonishing diversity of shapes: some are disordered, others already have a rotating disc that may end up as a spiral structure like the Milky Way, while yet others have been spotted in the process of merging. Another surprising observation is that certain galaxies appear to be ejecting gas, forming mysterious haloes around them. The survey thus raises a number of new questions about the early evolution of galaxies.

CAPTION

Mosaic showing some of the galaxies observed by ALMA. The bright yellow regions are those where the most stars are forming (the ionised carbon (C+) line makes it possible to see the formation of stars obscured by dust). The second image from the left in the top row shows a triple merger.

###

To find out more, read NRAO's news release:
https://public.nrao.edu/news/galaxies-in-the-infant-universe-were-surprisingly-mature/

Notes:

(1) Acronym for the ALMA Large Program to INvestigate C+ at Early times
(2) ALMA (Atacama Large Millimeter/submillimeter Array) is a telescope designed for the study of radiation from the coldest objects in the Universe, and consists of 66 antennas located in the Atacama desert in the Chilean Andes.
(3) from the Laboratoire d'Astrophysique de Marseille (CNRS/Aix-Marseille Université/CNES) and the Institut de Recherche en Astrophysique et Planétologie (CNRS/Université Toulouse III - Paul Sabatier/ CNES).
(4) They have already reached a mass similar to that of the Milky Way today.

Galaxies in the infant universe were surprisingly mature

ALMA telescope conducts largest survey yet of distant galaxies in the early universe

NATIONAL RADIO ASTRONOMY OBSERVATORY

Research News

    SHARE

 PRINT  E-MAIL

Volume 0%

 

VIDEO: BRIEF VIDEO EXPLAINING THIS RESEARCH RESULT. view more 

CREDIT: B. SAXTON NRAO/AUI/NSF

Massive galaxies were already much more mature in the early universe than previously expected. This was shown by an international team of astronomers who studied 118 distant galaxies with the Atacama Large Millimeter/submillimeter Array (ALMA).

Most galaxies formed when the universe was still very young. Our own galaxy, for example, likely started forming 13.6 billion years ago, in our 13.8 billion-year-old universe. When the universe was only ten percent of its current age (1-1.5 billion years after the Big Bang), most of the galaxies experienced a "growth spurt". During this time, they built up most of their stellar mass and other properties, such as dust, heavy element content, and spiral-disk shapes, that we see in today's galaxies. Therefore, if we want to learn how galaxies like our Milky Way formed, it is important to study this epoch.

In a survey called ALPINE (the ALMA Large Program to Investigate C+ at Early Times), an international team of astronomers studied 118 galaxies experiencing such a "growth spurt" in the early universe. "To our surprise, many of them were much more mature than we had expected," said Andreas Faisst of the Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology (Caltech).

Galaxies are considered more "mature" than "primordial" when they contain a significant amount of dust and heavy elements. "We didn't expect to see so much dust and heavy elements in these distant galaxies," said Faisst. Dust and heavy elements (defined by astronomers as all elements heavier than hydrogen and helium) are considered to be a by-product of dying stars. But galaxies in the early universe have not had much time to build stars yet, so astronomers don't expect to see much dust or heavy elements there either.

"From previous studies, we understood that such young galaxies are dust-poor," said Daniel Schaerer of the University of Geneva in Switzerland. "However, we find around 20 percent of the galaxies that assembled during this early epoch are already very dusty and a significant fraction of the ultraviolet light from newborn stars is already hidden by this dust," he added.

Many of the galaxies were also considered to be relatively grown-up because they showed a diversity in their structures, including the first signs of rotationally supported disks - which may later lead to galaxies with a spiral structure as is observed in galaxies such as our Milky Way. Astronomers generally expect that galaxies in the early universe look like train wrecks because they often collide. "We see many galaxies that are colliding, but we also see a number of them rotating in an orderly fashion with no signs of collisions," said John Silverman of the Kavli Institute for the Physics and Mathematics of the Universe in Japan.

ALMA has spotted very distant galaxies before, such as MAMBO-9 (a very dusty galaxy) and the Wolfe Disk (a galaxy with a rotating disk). But it was hard to say whether these discoveries were unique, or whether there were more galaxies like them out there. ALPINE is the first survey that enabled astronomers to study a significant number of galaxies in the early universe, and it shows that they might evolve faster than expected. But the scientists don't yet understand how these galaxies grew up so fast, and why some of them already have rotating disks.

Observations from ALMA were crucial for this research because the radio telescope can see the star formation that is hidden by dust and trace the motion of gas emitted from star-forming regions. Surveys of galaxies in the early universe commonly use optical and infrared telescopes. These allow the measurement of the unobscured star formation and stellar masses. However, these telescopes have difficulties measuring dust obscured regions, where stars form, or the motions of gas in these galaxies. And sometimes they don't see a galaxy at all. "With ALMA we discovered a few distant galaxies for the first time. We call these Hubble-dark as they could not be detected even with the Hubble telescope," said Lin Yan of Caltech.

To learn more about distant galaxies, the astronomers want to point ALMA at individual galaxies for a longer time. "We want to see exactly where the dust is and how the gas moves around. We also want to compare the dusty galaxies to others at the same distance and figure out if there might be something special about their environments," added Paolo Cassata of the University of Padua in Italy, formerly at the Universidad de Valparaíso in Chile.

ALPINE is the first and largest multi-wavelength survey of galaxies in the early universe. For a large sample of galaxies the team collected measurements in the optical (including Subaru, VISTA, Hubble, Keck and VLT), infrared (Spitzer), and radio (ALMA). Multi-wavelength studies are needed to get the full picture of how galaxies are built up. "Such a large and complex survey is only possible thanks to the collaboration between multiple institutes across the globe," said Matthieu Béthermin of the Laboratoire d'Astrophysique de Marseille in France.

###

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Media contact:

Iris Nijman
NRAO News and Public Information Manager
inijman@nrao.edu

A list of ALPINE publications to date can be found here: http://alpine.ipac.caltech.edu/#publications

All ALPINE papers are dedicated to the memory of Olivier Le Fèvre, Principal Investigator of ALPINE.

Co-Principal Investigators of ALPINE are:

- Andreas Faisst, Caltech/IPAC, USA

- Lin Yan, Caltech, USA

- Peter Capak, Caltech/IPAC, USA

- John Silverman, Kavli Institute for the Physics and Mathematics of the Universe, Japan

- Matthieu Béthermin, Laboratoire d'Astrophysique de Marseille, France

- Paolo Cassata, University of Padua, Italy

- Daniel Schaerer, University of Geneva, Switzerland

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

 

Antarctica yields oldest fossils of giant birds with 21-foot wingspans

Two fossils from a group of extinct seabirds represent the largest individuals ever found

UNIVERSITY OF CALIFORNIA - BERKELEY

Research News

 

IMAGE: AN ARTIST'S DEPICTION OF ANCIENT ALBATROSSES HARASSING A PELAGORNITHID -- WITH ITS FEARSOME TOOTHED BEAK -- AS PENGUINS FROLIC IN THE OCEANS AROUND ANTARCTICA 50 MILLION YEARS AGO. view more 

CREDIT: COPYRIGHT BRIAN CHOO

Fossils recovered from Antarctica in the 1980s represent the oldest giant members of an extinct group of birds that patrolled the southern oceans with wingspans of up to 21 feet that would dwarf the 11½-foot wingspan of today's largest bird, the wandering albatross.

Called pelagornithids, the birds filled a niche much like that of today's albatrosses and traveled widely over Earth's oceans for at least 60 million years. Though a much smaller pelagornithid fossil dates from 62 million years ago, one of the newly described fossils -- a 50 million-year-old portion of a bird's foot -- shows that the larger pelagornithids arose just after life rebounded from the mass extinction 65 million years ago, when the relatives of birds, the dinosaurs, went extinct. A second pelagornithid fossil, part of a jaw bone, dates from about 40 million years ago.

"Our fossil discovery, with its estimate of a 5-to-6-meter wingspan -- nearly 20 feet -- shows that birds evolved to a truly gigantic size relatively quickly after the extinction of the dinosaurs and ruled over the oceans for millions of years," said Peter Kloess, a graduate student at the University of California, Berkeley.

The last known pelagornithid is from 2.5 million years ago, a time of changing climate as Earth cooled, and the ice ages began.

Kloess is the lead author of a paper describing the fossil that appears this week in the open access journal Scientific Reports. His co-authors are Ashley Poust of the San Diego Natural History Museum and Thomas Stidham of the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences in Beijing. Both Poust and Stidham received their Ph.Ds from UC Berkeley.

CAPTION

This five-inch segment of fossilized jaw, which was discovered in Antarctica in the 1980s, dates from 40 million years ago. The skull of the bird would have been about two feet long, while the pseudoteeth, which were originally covered with horny keratin, would have been up to an inch long. At this scale, the bird's wingspan would have been 5 to 6 meters, or some 20 feet.

Birds with pseudoteeth

Pelagornithids are known as 'bony-toothed' birds because of the bony projections, or struts, on their jaws that resemble sharp-pointed teeth, though they are not true teeth, like those of humans and other mammals. The bony protrusions were covered by a horny material, keratin, which is like our fingernails. Called pseudoteeth, the struts helped the birds snag squid and fish from the sea as they soared for perhaps weeks at a time over much of Earth's oceans.

Large flying animals have periodically appeared on Earth, starting with the pterosaurs that flapped their leathery wings during the dinosaur era and reached wingspans of 33 feet. The pelagornithids came along to claim the wingspan record in the Cenozoic, after the mass extinction, and lived until about 2.5 million years ago. Around that same time, teratorns, now extinct, ruled the skies.

The birds, related to vultures, "evolved wingspans close to what we see in these bony-toothed birds (pelagornithids)," said Poust. "However, in terms of time, teratorns come in second place with their giant size, having evolved 40 million years after these pelagornithids lived. The extreme, giant size of these extinct birds is unsurpassed in ocean habitats,""

The fossils that the paleontologists describe are among many collected in the mid-1980s from Seymour Island, off the northernmost tip of the Antarctic Peninsula, by teams led by UC Riverside paleontologists. These finds were subsequently moved to the UC Museum of Paleontology at UC Berkeley.

Kloess stumbled across the specimens while poking around the collections as a newly arrived graduate student in 2015. He had obtained his master's degree from Cal State-Fullerton with a thesis on coastal marine birds of the Miocene era, between 17 million and 5 million years ago, that was based on specimens he found in museum collections, including those in the UCMP.

"I love going to collections and just finding treasures there," he said. "Somebody has called me a museum rat, and I take that as a badge of honor. I love scurrying around, finding things that people overlook."

Reviewing the original notes by former UC Riverside student Judd Case, now a professor at Eastern Washington University near Spokane, Kloess realized that the fossil foot bone -- a so-called tarsometatarsus -- came from an older geological formation than originally thought. That meant that the fossil was about 50 million years old instead of 40 million years old. It is the largest specimen known for the entire extinct group of pelagornithids.

The other rediscovered fossil, the middle portion of the lower jaw, has parts of its pseudoteeth preserved; they would have been up to 3 cm (1 inch) tall when the bird was alive. The approximately 12-cm (5-inch-) long preserved section of jaw came from a very large skull that would have been up to 60 cm (2 feet) long. Using measurements of the size and spacing of those teeth and analytical comparisons to other fossils of pelagornithids, the authors are able to show that this fragment came from an individual bird as big, if not bigger, than the largest known skeletons of the bony-toothed bird group.

A warm Antarctica was a bird playground

Fifty million years ago, Antarctica had a much warmer climate during the time known as the Eocene and was not the forbidding, icy continent we know today, Stidham noted. Alongside extinct land mammals, like marsupials and distant relatives of sloths and anteaters, a diversity of Antarctic birds occupied the land, sea and air.

The southern oceans were the playground for early penguin species, as well as extinct relatives of living ducks, ostriches, petrels and other bird groups, many of which lived on the islands of the Antarctic Peninsula. The new research documents that these extinct, predatory, large- and giant-sized bony-toothed birds were part of the Antarctic ecosystem for over 10 million years, flying side-by-side over the heads of swimming penguins.

"In a lifestyle likely similar to living albatrosses, the giant extinct pelagornithids, with their very long-pointed wings, would have flown widely over the ancient open seas, which had yet to be dominated by whales and seals, in search of squid, fish and other seafood to catch with their beaks lined with sharp pseudoteeth," said Stidham. "The big ones are nearly twice the size of albatrosses, and these bony-toothed birds would have been formidable predators that evolved to be at the top of their ecosystem."

Museum collections like those in the UCMP, and the people like Kloess, Poust and Stidham to mine them, are key to reconstructing these ancient habitats.

"Collections are vastly important, so making discoveries like this pelagornithid wouldn't have happened if we didn't have these specimens in the public trust, whether at UC Riverside or now at Berkeley," Kloess said. "The fact that they exist for researchers to look at and study has incredible value."

###

Black Hispanic individuals hardest hit by COVID-19

Higher death, hospitalization rates compared to non-white Hispanic individuals, variable by race

BOSTON MEDICAL CENTER

Research News

 

Boston - Results from a new study led by Boston Medical Center (BMC) demonstrate the disproportionate impact of COVID-19 on Hispanic groups within the US, with the most severe outcomes, including death and intensive care, among Hispanic Black individuals. Analyzing data from the Centers for Disease Control and Prevention, researchers found differences between Hispanic groups, with higher rates of hospitalization and increased risk of death for Hispanic Black compared to Hispanic multiracial individuals. Published online in the Journal of Immigrant and Minority Health, the results highlight that Hispanic populations as a whole have worse COVID-19 outcomes compared to the Hispanic white population, demonstrating the need for more accurate demographic data collection efforts in order to better address the disparities among Hispanic individuals impacted by COVID-19.

Results from previous COVID-19 research have shown that Latinx populations, as a whole, have worse outcomes compared to other ethnic groups. This study, the first to use a nationally representative COVID-19 database, delves further into the data to investigate the differential impact of COVID-19 on different racial groups within the Hispanic community.

For this study, researchers analyzed data reported to the Centers for Disease Control and Prevention between April 5 and May 18, 2020, with a cohort of 78,323 individuals. They compared hospitalization, intensive care unit admission, need for breathing support, and death rates among Hispanic white, Hispanic Black, and Hispanic multiracial/other groups. Next, they compared these results with the data on the above criteria for non-Hispanic white individuals.

Hispanic Black individuals in the cohort had the highest rate of comorbidities, at 51 percent, as well as hospitalizations, which were 45 percent. Hispanic/multiracial individuals were more frequently admitted to the intensive care unit (10 percent), had the highest incidence of requiring breathing support through mechanical ventilation (10 percent) and more frequent rates of death due to COVID-19 (16.1 percent). Overall, Hispanic groups fared worse than non-Hispanic white individuals. The relative risk of death was 1.36, 1.72 and 1.68 times higher for Hispanic white, Hispanic Black and Hispanic multiracial compared to non-Hispanic white individuals.

"Our results clearly show that Hispanic individuals are more likely to be hospitalized and die from COVID-19 infection than non-Hispanic individuals, with the worst outcomes among Hispanic Black individuals," said Sarah Kimball, MD, co-director of BMC's Immigrant & Refugee Health Center and the study's corresponding author. One of the challenges, the authors note, is the incomplete information on race and ethnicity included in the reported data given variations among how the information is collected and reported. At this time, there are no universal standards or processes in place at health care institutions related to how racial or ethnic information is collected from patients.

"The dilemma is that we know these disparities among racial groups aren't biological, and reflect the systemic impacts of racism and inequality. Yet, we need better data collection on racial and ethnic groups, in order to develop interventions tailored to address the COVID-19 disparities among specific patient populations," added Kimball, who is also an assistant professor of medicine at Boston University School of Medicine. "The better data we have access to, the more targeted we can be in our public health and treatment approaches to dismantle the effects of racism and the disparities that we see among different groups within the Hispanic community, which can help decrease COVID-19-specific disparities in these individuals."

###

This study was funded in part by the National Institutes of Health.

About Boston Medical Center
Boston Medical Center (BMC) is a private, not-for-profit, 514-bed, academic medical center that is the primary teaching affiliate of Boston University School of Medicine. It is the largest and busiest provider of trauma and emergency services in New England. BMC offers specialized care for complex health problems and is a leading research institution, receiving more than $166 million in sponsored research funding in fiscal year 2019. It is the 13th largest funding recipient in the U.S. from the National Institutes of Health among independent hospitals. In 1997, BMC founded Boston Medical Center Health Plan, Inc., now one of the top ranked Medicaid MCOs in the country, as a non-profit managed care organization. Boston Medical Center and Boston University School of Medicine are partners in Boston HealthNet - 12 community health centers focused on providing exceptional health care to residents of Boston. For more information, please visit http://www.bmc.org.

 

Low cost, customized prosthesis using 3D printing

SUTD, together with Tan Tock Seng Hospital, developed a novel 3D printed non-metallic self-locking prosthetic arm for a patient with a forequarter amputation - it is more comfortable, flexible and 20% cheaper than a conventional prosthesis.

SINGAPORE UNIVERSITY OF TECHNOLOGY AND DESIGN

Research News

 

IMAGE: THE SCHEMATIC REPRESENTATION OF THE VARIOUS STAGES INVOLVED IN THE USER-CENTERED, ITERATIVE PROCESS OF PROSTHESIS DESIGN. view more 

CREDIT: SUTD

Upper limb forequarter amputations which involve the removal of the entire arm and scapula require highly customized prosthetic devices that are expensive but yet, usually underutilized due to their high maintenance and low comfort levels. At the same time, while cosmetic prostheses - artificial limbs which provide patients the appearance of a pre-amputated body part - have a higher rate of continuous use, they have limitations in functional use.

Combining both technical and clinical expertise, the Singapore University of Technology and Design's (SUTD) Medical Engineering and Design Laboratory collaborated with Tan Tock Seng Hospital's (TTSH) Foot Care and Limb Design Centre, the largest provider of prosthetic services in Singapore, on a patient-specific upper limb prosthesis. This cosmetic prosthesis with a self-locking function was found to be more comfortable and around 20 percent cheaper compared to similar prostheses available in the industry.

To reduce the underutilization and delivery time, while taking improved fit, function and comfort into consideration, the research team turned to 3D printing due to its versatility and ability to cater to the device's geometrical and functional complexity.

The team also adopted a user-centered design approach, involving the patient throughout the customized design and development process. They then meticulously captured and documented the design process so that it can serve as a blueprint for other device applications or be replicated for other patients with limb amputations, thus reducing the over reliance on a prosthetist's judgement, skills and experience for an optimal fit.

Based on regular consultations with the patient and prosthetist at TTSH, including the shadowing of the patient to better understand his daily activities and functional needs, it was concluded that the new prosthesis needed to be lightweight, capable of dissipating heat, locking at 90° of flexion, comfortable to wear and void of metal components that would be detectable by airport scanners.

The research team used a digital scanner to capture residuum and contralateral arm geometries to replicate the patient's arm with high precision. They then designed different parts of the prosthesis from the captured geometries, 3D printed and verified these for fit, comfort, and function (refer to image). Their research paper was published in the Prosthetics and Orthotics International Journal.

The patient's satisfaction for the 3D printed prosthesis over his conventionally made prosthesis rated higher for its overall effectiveness, accurate size, symmetrical appearance and ease of use. Even though the new prosthesis weighed 100 grams more than the current prosthesis, the patient preferred it due to its improved suspension contributing to the feel of a lighter arm during use. However, the prosthesis was perceived to be less durable due to the patient's unfamiliarity with the quality of 3D printing, his concerns of the elbow locking mechanism breaking, and the appearance of the mesh structure compared to his current prosthesis.

"Digitalization and 3D printing have been transforming the design and manufacture of complex medical devices, surgery planning, medical education, and care delivery. Even though 3D printing technology has been around for more than three decades since the early 90's, it wasn't until recently that people really began to appreciate and trust it for end-use fabrication. In this work, 3D printing freed us from the manufacturing constraints and enabled us to optimize the design to suit the patient's needs. More importantly, this work sets the groundwork for future patient-specific end-use 3D printed parts for prosthetic needs," said principal investigator, Assistant Professor Subburaj Karupppasamy from SUTD's Engineering Product Development pillar.

Trevor Binedell, Principal Prosthetist at the Foot Care and Limb Design Centre, TTSH, and PhD student from SUTD, added, "The collaboration between TTSH and SUTD has led to a great outcome for this patient. User-design and the digitalization techniques have elevated the levels of patient-specific care to create individual designs that truly meet the needs of the user. This process has the potential to improve unique designs for many of our patients and enhance their quality of lives."

###

 

Irregular appearances of glacial and interglacial climate states

A clearer picture of the sequence of glacial and interglacial periods

ALFRED WEGENER INSTITUTE, HELMHOLTZ CENTRE FOR POLAR AND MARINE RESEARCH

Research News

 

During the last 2.6 million years of Earth's climate has altered between glacial and interglacial states. As such, there have been times in which the transition between the two climate states appeared with either regular or irregular periodicity. AWI researcher Peter Köhler has now discovered that the irregular appearance of interglacials has been more frequent than previously thought. His study makes a significant contribution to our understanding of Earth's fundamental climate changes.

In order to understand human beings' role in the development of our current climate, we have to look back a long way, since there has always been climate change - albeit over vastly different timescales than the anthropogenic climate change, which is mainly due to the use of fossil fuels over the past 200 years. Without humans, for millions of years, climate altered between glacial and interglacial states over periods of many thousands of years, mainly because of the Earth's tilt which changes by a few degrees with a periodicity of 41,000 years. This in turn changes the angle at which the sun's rays strike Earth - and as such the energy that reaches the planet, especially at high latitudes in summer. However, there is strong evidence that during the course of the last 2.6 million years, interglacials have repeatedly been 'skipped'. The Northern Hemisphere - particularly North America - remained frozen for long periods, despite the angle of the axial tilt changing to such an extent that more solar energy once again reached Earth during the summer, which should have melted the inland ice masses. This means Earth's tilt can't be the sole reason for Earth's climate to alter between glacial and interglacial states.

In order to solve the puzzle, climate researchers are investigating more closely at what points in Earth's history irregularities occurred. Together with colleagues at Utrecht University, physicist Peter Köhler from the Alfred Wegener Institute (AWI) has now made a significant contribution towards providing a clearer picture of the sequence of glacial and interglacial periods over the last 2.6 million years. Until now, experts thought that, especially over the past 1.0 million years, glacial and interglacial periods deviated from their 41,000- year cycle, and that interglacial periods were skipped, as a result of which some glacial periods lasted for 80,0000 or even 120,000 years. "For the period between 2.6 and 1.0 million years ago, it was assumed that the rhythm was 41,000 years," says Peter Köhler. But as his study, which has now been published in the scientific journal Nature Communications, shows, there were also repeated irregularities during the period between 2.6 and 1.0 million years ago.

Köhler's study is particularly interesting because he re-evaluated a well-known dataset that researchers have been using for several years - the LR04 climate dataset - yet arrived at completely different conclusions. This dataset consists of a global evaluation of core samples from deep-sea sediments that are millions of years old, and includes measurements from the ancient shells of microscopic, single-celled marine organisms - foraminifera - that were deposited on the ocean floor. Foraminifera incorporate oxygen from the seawater into their calcium shells. But over millennia, the level of specific oxygen isotopes - oxygen atoms that have differing numbers of neutrons and therefore different masses - varies in seawater.

18O reveals what the world was like in the past

The LR04 dataset contains measurements of the ratio of the heavy oxygen isotope 18O to the lighter 16O. The ratio of 18O/16O stored in the foraminifera's shells depends on the water temperature. But there is also another effect that leads to relatively large amounts of 18O being found in the foraminifera's shells in glacial periods: when, during the course of a glacial period, there is heavy snowfall on land, which leads to the formation of thick ice sheets, the sea level falls - in the period studied, by as much as 120 m. Since 18O is heavier than 16O, water molecules containing this heavy isotope evaporate less readily than molecules containing the lighter isotope. As such, comparatively more 18O remains in the ocean and the 18O content of the foraminifera shells increases. "If you take the LR04 dataset at face value, it means you blur two effects - the influence of ocean temperature and that of land ice, or rather that of sea level change," says Peter Köhler. "This makes statements regarding the alternation of the glacial periods uncertain." And there is an additional factor: climate researchers mainly determine the sequence of glacial periods on the basis of glaciation in the Northern Hemisphere. But using 18O values doesn't allow us to say whether prehistoric glaciation chiefly occurred in the Northern Hemisphere or in Antarctica.

Computer model separates the influencing parameters

In an attempt to solve this problem, Köhler and his team evaluated the LR04 dataset in a completely different way. The data was fed into a computer model that simulates the growth and melting of the large continental ice sheets. What sets it apart: the model is capable of separating the influence of temperature and that of sea level change on the 18O concentration. Furthermore, it can accurately analyse where and when snow falls and the ice increases - more in the Northern Hemisphere or in Antarctica. "Mathematicians call this separation a deconvolution," Köhler explains, "which our model is capable of delivering." The results show that the sequence of glacials and interglacials was irregular even in the period 2.6 to 1.0 million years ago - a finding that could be crucial in the coming years. As part of the ongoing major EU project 'BE-OIC (Beyond EPICA Oldest Ice Core)', researchers are drilling deeper than ever before into the Antarctic ice. With the oldest ice core recovered to date, 'EPICA', they have 'only' travelled back roughly 800,000 years into the past. The ancient ice provides, among other things, information on how much carbon dioxide Earth's atmosphere contained at that time. With 'Beyond EPICA' they will delve circa 1.5 million years into the past. By combining the carbon dioxide measurements with Köhler's analyses, valuable insights can be gained into the relation between these two factors - the fluctuations in the sequence of glacials and the carbon dioxide content of the atmosphere. And this can help us understand the fundamental relationship between greenhouse gases and climate changes in Earth's glacial history.

###

 

Shifts in flowering phases of plants due to reduced insect density

Research group of Jena University and iDiv uses novel research method to study effect of insect decline on plant biodiversity

FRIEDRICH-SCHILLER-UNIVERSITAET JENA

 

IMAGE: DOCTORAL CANDIDATE JOSEPHINE ULRICH FROM THE RESEARCH TEAM OF THE UNIVERSITY OF JENA. view more 

CREDIT: (IMAGE: ANNE GÜNTHER/UNIVERSITY OF JENA)

(Jena, Germany) It still sounds unlikely today, but declines in insect numbers could well make it a frequent occurrence in the future: fields full of flowers, but not a bee in sight.

A research group of the University of Jena (Germany) and the German Centre for Integrative Biodiversity Research Halle-Jena-Leipzig (iDiv) has discovered that insects have a decisive influence on the biodiversity and flowering phases of plants. If there is a lack of insects where the plants are growing, their flowering behaviour changes. This can result in the lifecycles of the insects and the flowering periods of the plants no longer coinciding. If the insects seek nectar at the wrong time, some plants will no longer be pollinated.

Innovative research method in iDiv Ecotron

Ecosystems are changing around the world, in particular due to global warming and altered land use. Insect species are dying out and the insect biomass is decreasing. Researchers have therefore studied how the biodiversity of plants is changing in the context of climate change. For this purpose, various climate scenarios have been simulated, using different temperatures and precipitation.

In a new study reported in the specialist journal Frontiers in Plant Science, the Working Group Biodiversity of Plants of the University of Jena, led by Prof. Christine Römermann, presents a different research approach. In cooperation with scientists from iDiv, led by Prof. Nico Eisenhauer, the researchers are focusing on the influence of invertebrates, such as insects, on the biodiversity and flowering behaviour of plants.

"We know that the insect biomass is decreasing," says Josephine Ulrich, a doctoral candidate from Römermann's team, referring to a study from 2017 which detected that insects had declined by 75 per cent over the previous 30 years.

The Jena research group has now studied in detail for the first time the extent to which decreasing insect density influences plant development. Whereas previous studies had only carried out field experiments, the research team used the "Ecotron", an iDiv research facility where identical climatic situations can be simulated in artificial ecosystems and observed with cameras.

In their experiment, the researchers studied how plant composition and plant development change if the number of insects falls by three-quarters.

Mismatch between plant and animal worlds

Ulrich and her colleagues discovered that the reduced insect biomass brings about a change in plant species. It is especially the dominant plant species, such as red clover, which become more prevalent. The development of the flowering period also changes as insect density declines. Some of the plants studied flowered earlier and others later.

"These changes can lead to mismatches between plant and animal species, which lead to adverse consequences for the ecosystem," says Ulrich, the lead author of the study. Examples are the food supply of insects and pollination success. This deterioration in the ecosystem function could entail further losses of insect and plant species. An additional consequence could be that plants become increasingly infested with pests. Due to the falling numbers of insects that feed on aphids, for example, these pests could spread unchecked.

###

Haunted house researchers investigate the mystery of playing with fear

ASSOCIATION FOR PSYCHOLOGICAL SCIENCE

Research News

    SHARE

 PRINT  E-MAIL

Volume 0%

 

VIDEO: HAUNTED HOUSES, HORROR MOVIES, AND GHOST STORIES CAN BE CHILLING DELIGHTS, PROVIDED THE FEAR THEY EVOKE REMAINS IN A "GOLDILOCKS ZONE " THAT IS NEITHER TOO TERRIFYING NOR TOO TAME. view more 

CREDIT: APS

Chainsaw-wielding maniacs and brain-munching zombies are common tropes in horror films and haunted houses, which, in normal years, are popular Halloween-season destinations for thrill seekers. But what makes such fearsome experiences so compelling, and why do we actively seek them out in frightful recreational settings?

New research accepted for publication in the journal Psychological Science reveals that horror entertains us most effectively when it triggers a distinct physical response--measured by changes in heart rate--but is not so scary that we become overwhelmed. That fine line between fun and an unpleasant experience can vary from person to person.

"By investigating how humans derive pleasure from fear, we find that there seems to be a 'sweet spot' where enjoyment is maximized," said Marc Malmdorf Andersen, a researcher at the Interacting Minds Center at Aarhus University and lead author of the paper. "Our study provides some of the first empirical evidence on the relationship between fear, enjoyment, and physical arousal in recreational forms of fear."

For years, researchers have suspected that physiological arousal, such as a quickening pulse and a release of hormones in the brain, may play a key role in explaining why so many people find horror movies and haunted houses so attractive.

Until now, however, a direct relationship between arousal and enjoyment from these types of activities has not been established. "No prior studies have analyzed this relationship on subjective, behavioral, as well as physiological levels," said Andersen.

To explore this connection, Andersen and his colleagues studied how a group of 110 participants responded to a commercial haunted house attraction in Vejle, Denmark. The researchers fitted each participant with a heart rate monitor, which recorded real-time data as they walked through the attraction. The nearly 50-room haunted house produced an immersive and intimate live-action horror experience. The attraction used a variety of scare tactics to frighten guests, including frequent jump scares, in which zombies or other monstrous abominations suddenly appeared or charged toward the guest.

The researchers also studied the participants in real time through closed-circuit monitors inside the attraction. This enabled the team to make first-hand observations of participants' reactions to the most frightening elements, and, subsequently, to have independent coders analyze participants' behavior and responses. After the experience, participants evaluated their level of fright and enjoyment for each encounter. By comparing these self-reported experiences with the data from the heart rate monitors and surveillance cameras, the researchers were able to compare the fear-related and enjoyment-related elements of the attraction on subjective, behavioral, and physiological levels.

What Is Recreational Fear?

Recreational fear refers to the mixed emotional experience of feeling fear and enjoyment at the same time. Fear is generally considered to be an unpleasant emotion that evolved to protect people from harm. Paradoxically, humans sometimes seek out frightening experiences for purely recreational purposes. "Past studies on recreational fear, however, have not been able to establish a direct relationship between enjoyment and fear," said Andersen.

Studies on fearful responses to media, for example, have mostly been conducted in laboratory settings with relatively weak stimuli, such as short video clips from frightening films. Such experimental setups can sometimes make it difficult to measure physiological arousal because responses may be modest in a laboratory context.

"Conducting our study at a haunted attraction, where participants are screaming with both fear and delight, made this task easier," said Andersen. "It also presented unique challenges, such as the immensely complex logistics associated with conducting empirical studies in a 'messy' real-world context like a haunted house."

Discovering the "Goldilocks Zone"

Plotting the relationship between self-reported fear and enjoyment, the researchers discovered an inverted U-shape trend, revealing an apparent sweet spot for fear where enjoyment is maximized.

"If people are not very scared, they do not enjoy the attraction as much, and the same happens if they are too scared," said Andersen. "Instead, it seems to be the case that a 'just-right' amount of fear is central for maximizing enjoyment."

The data also showed a similar inverted U-shape for the participants' heart rate signatures, suggesting that enjoyment is related to just-right deviations from a person's normal physiological state. However, when fearful encounters trigger large and long-lasting deviations from this normal state, as measured by pulse rates going up and down frequently over a longer period of time, unpleasant sensations often follow.

"This is strikingly similar to what scientists have found to characterize human play," said Andersen. "We know, for instance, that curiosity is often aroused when individuals have their expectations violated to a just-right degree, and several accounts of play stress the importance of just-right doses of uncertainty and surprise for explaining why play feels enjoyable."

In other words, when horror fans are watching Freddy Krueger on TV, reading a Stephen King novel, or screaming their way through a haunted attraction, they are essentially playing with fear.

###

Psychological Science, the flagship journal of APS, is the leading peer-reviewed journal publishing empirical research spanning the entire spectrum of the science of psychology. Journalists may request an unedited copy of the manuscript by contacting news@psychologicalscience.org.

Hard physical work significantly increases the risk of dementia

UNIVERSITY OF COPENHAGEN THE FACULTY OF HEALTH AND MEDICAL SCIENCES

Research News

 

The muscles and joints are not the only parts of the body to be worn down by physical work. The brain and heart suffer too. A new study from the University of Copenhagen shows that people doing hard physical work have a 55-per cent higher risk of developing dementia than those doing sedentary work. The figures have been adjusted for lifestyle factors and lifetime, among other things.

The general view has been that physical activity normally reduces the risk of dementia, just as another study from the University of Copenhagen recently showed that a healthy lifestyle can reduce the risk of developing dementia conditions by half.

Here the form of physical activity is vital, though, says associate professor Kirsten Nabe-Nielsen from the Department of Public Health at the University of Copenhagen.

"Before the study we assumed that hard physical work was associated with a higher risk of dementia. It is something other studies have tried to prove, but ours is the first to connect the two things convincingly," says Kirsten Nabe-Nielsen, who has headed the study together with the National Research Centre for the Working Environment with help from Bispebjerg-Frederiksberg Hospital.

"For example, the WHO guide to preventing dementia and disease on the whole mentions physical activity as an important factor. But our study suggests that it must be a 'good' form of physical activity, which hard physical work is not. Guides from the health authorities should therefore differentiate between physical activity in your spare time and physical activity at work, as there is reason to believe that the two forms of physical activity have opposite effects," Kirsten Nabe-Nielsen says and explains that even when you take smoking, blood pressure, overweight, alcohol intake and physical activity in one's spare time into account, hard physical work is associated with an increased occurrence of dementia.

One of the study's co-authors is Professor MSO Andreas Holtermann from the National Research Centre for the Working Environment. He hopes the dementia study from the University of Copenhagen will contribute to shine a spotlight on the importance of prevention, as changes in the brain begin long before the person leaves the labour market.

"A lot of workplaces have already taken steps to improve the health of their staff. The problem is that it is the most well-educated and resourceful part of the population that uses these initiatives. Those with a shorter education often struggle with overweight, pain and poor physical fitness, even though they take more steps during the day and to a larger extent use their body as a tool. For workmen, it is not enough for example to avoid heavy lifts if they wish to remain in the profession until age 70. People with a shorter education doing manual labour also need to take preventive steps by strengthening the body's capacity via for example exercise and strength training," he says.

The study is based on data from the Copenhagen Male Study (CMS), which included 4,721 Danish men, who back in the 1970s reported data on the type of work they did on a daily basis. The study included 14 large Copenhagen-based companies, the largest being DSB, the Danish Defence, KTAS, the Postal Services and the City of Copenhagen.

Through the years, the researchers have compiled health data on these men, including data on the development of dementia conditions.

According to Kirsten Nabe-Nielsen, previous studies have suggested that hard physical work may have a negative effect on the heart blood circulation and thus also on the blood supply to the brain. This may for example lead to the development of cardiovascular diseases like high blood pressure, blood clots in the heart, heart cramps and heart failure.

The National Research Centre for the Working Environment continues to work on the results with a view to identifying healthier ways of doing hard physical work. They have therefore begun to collect data from social and healthcare assistants, child care workers and packing operatives, among others, in order to produce interventions meant to organise hard physical work in such a way that it has an 'exercise effect'.

They thus hope to see companies successfully change work procedures, ensuring for example that heavy lifts will have a positive effect rather than wear down the workers. The results will be published on an ongoing basis.

###

Read the entire study, 'The effect of occupational physical activity on dementia: Results from the Copenhagen Male Study', in the Scandinavian Journal of Medicine and Science in Sports.