Tuesday, July 26, 2022

Particle phase chemistry enables soot to better seed clouds

New study challenges current understanding of the formation mechanism

New study challenges current understanding of the formation mechanism of atmospheric secondary organic aerosol – Particle chemistry appears to have a strong influence on the climate impact of soot and organic aerosols from wildfires or anthropogenic combustion.

Peer-Reviewed Publication

MAX PLANCK INSTITUTE FOR CHEMISTRY

Highly oxygenated organic molecules are a key component of atmospheric secondary organic aerosol. However, the origin and formation mechanism of highly oxygenated organic molecules with high unsaturation (HU-HOMs), remain unknown. But now an international team of researchers has found that photooxidation of large polycyclic aromatic hydrocarbons (PAHs) on soot by singlet oxygen and superoxide anion radicals can be an important source of the unexplained HU-HOMs widely observed in the atmosphere. The team was led by Yafang Cheng from the Max Planck Institute for Chemistry and Chuncheng Chen from the Institute of Chemistry, Chinese Academy of Sciences. Their results are based on molecular-level investigations of the photochemical aging of soot by O2. The PAH-derived HU-HOMs exhibit lactone and anhydride functional groups and can substantially increase the hydrophilicity of soot.

The increase in the hydrophilicity of soot after photochemical aging is expected to further influence the fate and effects of soot aerosols in the atmosphere: e.g., becoming better cloud condensation nuclei, more easily being involved in aqueous phase chemistry and aging, altering its wet deposition process etc.

Deciphering the molecular formulae

The researchers characterized the evolution of molecular composition during the photoaging of soot by applying laser desorption ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (LDI FT-ICR MS), an ultrahigh-resolution mass spectrometry technique allowing confident assignment of the molecular formulae. In situ attenuated total internal reflection IR (ATR-IR) was used to investigate the evolution of functional groups during soot oxidation. They find that highly oxygenated organic molecules with high unsaturation (HU-HOMs) are formed through a multigenerational photochemical oxidation pathway, where ketones, aldehydes, and acids are produced by the photooxidation of large polycyclic aromatic hydrocarbons on soot in the initial stage, followed by the formation and accumulation of lactones and anhydrides on further oxidation.

“In this heterogeneous photochemical oxidation, O2 molecules are the initial oxidant, which is further photosensitized to form reactive oxygen species such as singlet oxygen and superoxide anion radicals,” said Meng Li, postdoc in Yafang Cheng’s group and the first author of the study. “Considering the abundance of O2 in the troposphere, this oxidation pathway should be a very important aging process for PAHs and soot particles, especially in clean and remote regions”, added Meng Li.

“This new HU-HOM formation pathway could be a characteristic evolution pathway of primary organic aerosols from various combustions, due to the widespread existence of PAHs there, thus contributing to a more comprehensive understanding of the chemical evolution of organic aerosols”, said Yafang Cheng who leads the Minerva Independent Research Group at the MPIC.

JOURNAL

Chem

DOI

10.1016/j.chempr.2022.06.011

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Highly Oxygenated Organic Molecules with High Unsaturation Formed upon Photochemical Aging of Soot

Revealing how different parts of mixed convective-stratiform clouds distinctly respond to cloud seeding

Peer-Reviewed Publication

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

Cloud seeding is a method of placing condensation nuclei into clouds that induce rain or snowfall. Seeding is a complex process, and its effectiveness depends on the target cloud type. To better understand the mechanisms behind seeding, in a recent study, scientists showed how a connected mixture of both convective and stratiform clouds responds to cloud seeding.

Using data from Ka-band cloud profiling radar (KPR) measurements onboard aircraft, along with the remote sensing observations from SNPP and Himawari-8 satellites, members of the Hubei Weather Modification innovation team (HBWM), under the guidance of Prof. Chuanfeng ZHAO from Beijing Normal University (Currently at Peking University), published their findings in Advances in Atmospheric Sciences.

“A mixed convective-stratiform cloud is one type of precipitating cloud with complex structure, composed of both cumulus clouds and stratiform clouds.” said the study’s first author, Dejun LI, Chief Expert on Weather Modification in Hubei Province.

LI elaborated that the successful launch of NPP in 2011, Himawari-8 in 2014, and the new high-resolution instrument components of KPR developed by satellite scientists at the University of Wyoming in 2014, all make observing the fine structure of cloud properties possible. This study measures the properties of mixed convective-stratiform clouds using KPR onboard aircraft in China for the first time.

Based on the KPR measurements before and after seeding, along with multi-source data including satellite observations, researchers now have the ability to analyze the characteristics of icing seeding tracks within the stratiform region and cloud seeding mechanisms in the convective region. This wealth of data gives important clues that help determine the differences in the cloud’s macro- and micro-physical properties.

“Few researchers have carried out studies regarding the characteristics and mechanisms of cloud responses to seeding at different parts of clouds.” said Dr. LI. “This is mainly due to the scarcity of observation instruments for cloud macro- and micro- physical properties, the insufficiency of confidence from single source of cloud observations, and so on.”

According to corresponding author Prof. ZHAO, the distinct seeding responses of stratiform and convective regions within a stratocumulus cloud are quite different. In the convective region, the cloud top is higher, which is associated with more released heat and stronger convection due to water-ice conversion. This results in both a greater number of and larger precipitation particles.

Within the stratiform region, the radar echo becomes weaker near cloud tops, indicating that liquid droplets are converting to ice crystals faster than in the convective region, causing icing seeding tracks to occur.

“Now that we have discovered how these mechanisms between the convective and stratiform regions respond to cloud seeding, future studies should further investigate application into mesoscale weather model simulations.” adds Prof. ZHAO.

JOURNAL

Advances in Atmospheric Sciences

DOI

10.1007/s00376-022-2003-8

ARTICLE TITLE

Macro- and Micro-physical Characteristics of Different Parts of Mixed Convective-stratiform Clouds and Differences in Their Responses to Seeding

ARTICLE PUBLICATION DATE

23-Jul-2022

Not just fun and games: Federal Hall exhibition explores the Bill of Rights

Business Announcement

NYU TANDON SCHOOL OF ENGINEERING

BROOKLYN, New York, Monday, July 25, 2022 – Visitors to the Federal Hall National Memorial in New York City will encounter an interactive art project comprising games designed to bring elements of the Bill of Rights to life in an exhibition of immersive digital games. The project, “Shall Make, Shall Be: The Bill of Rights at Play,” which opened July 4, 2022 and runs through August 31 at the Federal Hall’s Grand Rotunda.

The exhibition, commemorating the 230th anniversary of the Bill of Rights through an interactive collection of works, comprises ten commissioned games, each addressing one of the first ten amendments to the U.S. Constitution. It was designed to involve visitors in ways to consider the underpinnings of what it means to be an American by re-framing the documents that serve as the foundation of U.S. political experience with familiar games — puzzles, arcade games, and popular video game genres, among others.

R. Luke DuBois, Associate Professor and Co-Director of the Integrated Design & Media program at the NYU Tandon School of Engineering, who conceived the project, said the works draw on the document’s effects, interpretations, and legal meanings in U.S. culture.

“The exhibition consists of critical games, using the mechanisms of play to interrogate, critique, and inform our understanding of civil liberties in the 21st Century,” he said.

The ten artists, game designers, and collectives selected through an open call to produce the games include: arts.codes (Melissa F. Clarke and Margaret Schedel); Peter Bradley; Danielle Isadora Butler; Arnab Chakravarty, Moaw!, and Ian McNeely; Cherisse Datu and Latoya Peterson; Ryan Kuo; Andy Malone; Shawn Pierre, Vi Trinh; and Lexa Walsh.

The exhibition was organized by DuBois with Laine Nooney, Assistant Professor of Media, Culture, and Communication at the NYU’s Steinhardt School of Culture, Education, & Human Development; and John Sharp, Professor of Games and Learning at Parsons School of Design, with support from the Frank-Ratchye STUDIO for Creative Inquiry and Professor of Electronic Art at Carnegie Mellon University.

“Shall Make, Shall Be: The Bill of Rights at Play” is co-presented at Federal Hall with the National Parks of New York Harbor Conservancy.

About the New York University Tandon School of Engineering

The NYU Tandon School of Engineering dates to 1854, the founding date for both the New York University School of Civil Engineering and Architecture and the Brooklyn Collegiate and Polytechnic Institute. A January 2014 merger created a comprehensive school of education and research in engineering and applied sciences as part of a global university, with close connections to engineering programs at NYU Abu Dhabi and NYU Shanghai. NYU Tandon is rooted in a vibrant tradition of entrepreneurship, intellectual curiosity, and innovative solutions to humanity’s most pressing global challenges. Research at Tandon focuses on vital intersections between communications/IT, cybersecurity, and data science/AI/robotics systems and tools and critical areas of society that they influence, including emerging media, health, sustainability, and urban living. We believe diversity is integral to excellence, and are creating a vibrant, inclusive, and equitable environment for all of our students, faculty and staff. For more information, visit engineering.nyu.edu.

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When the invasive fish are native

UB study warns about the ecological impact of native species in waters that do not correspond to them

Peer-Reviewed Publication

UNIVERSITY OF BARCELONA

Translocated species — IMAGE: THE TRANSLOCATED SPECIES CAN BE AS MUCH OF A PROBLEM FOR BOTH NATIVE FISH AND EXOTIC FISH, ACCORDING TO THE STUDY. view more
CREDIT: ADOLFO DE SOSTOA (UNIVERSITY OF BARCELONA - IRBIO)

Exotic fish are a threat to river ecosystems, but what happens when invasive species are native to a territory and have been introduced into waters that are not their original territory? A new study carried out by the UB and published in the journal Science of The Total Environment, has analysed the impact the native fish receive from these species, called translocated species, compared to the effects of exotic invasive species, i.e, those that are not native to any basin in the territory.

The conclusions of the study show that the quality of the habitat is the most important factor for the wellbeing of native fish, but the study also points out that translocated species can become as problematic as the exotic ones.

According to the researchers, these results can have implications in the management of rivers, specially in the context of climate change, since species translocation is a common effect of inter-regional water transfers carried out by some countries to mitigate the consequences of global warming.

"What our data suggest is that invasions by translocated native species should be taken at least as seriously as those by exotic species in the systems we studied, i.e. the typical medium-sized Mediterranean streams and rivers", notes Alberto Maceda, researcher at the Biodiversity Research Institute (IRBio) of the University of Barcelona and first author of the article. The study included the participation of Adolfo de Sostoa, researcher at IRBio, and experts Ralph Mac Nally and Jian D.L. Yen, from the University of Melbourne (Australia).

A pioneering study on the effects of translocated species

The researchers studied the characteristics of different fish species in fifteen sites of the basins of the north-eastern Iberian Peninsula, but they focused especially on cyprinid species (Cyprinidae), one with the highest species richness in the world and the most common in Europe.

Specifically, researchers analysed indicators of great ecological relevance, such as the native species diversity, abundance and size distribution of native fish when exposed to invasion by exotic or translocated native species. "Before our study, there were studies that highlighted the problem of mixing populations of Mediterranean and Atlantic trout, and some examples of competition between native and translocated native species, but ours is the first study that has analysed the problem from a broader point of view and has combined different indicators", says Alberto Maceda, lecturer at the Faculty of Biology of the UB.

Negative effects on native fish

The results, in line with previous studies, indicate that habitat quality is essential for the conservation of native species. That is, environmental features, such as temperature, water depth or velocity, pH or nutrient levels, are the variables that best explain the variability in characteristics such as abundance or weight of the analysed native species. However, the main novelty of the study is that, after considerng these environmental variables, the results suggest that the translocated species had potentially greater impacts on native fish than the exotic species, despite the fact that the latter contained some widely recognised exotic species, such as carps (Cyprinus carpio) or bleaks (Alburnus alburnus).

As stated by the authors in the paper, the presence of translocated fish was associated with a lower abundance and richness of native fish and smaller native individuals, while the presence of exotic fish was associated with a higher abundance and richness of native fish and generally larger individuals.

There are still many unanswered questions about translocated species

Given the results, the researchers stress the need to study the ecological impact of translocated native species in greater detail. "It is no good assuming that the impacts of exotic species are worse because they come from outside our borders, as we do not yet have enough information to make such assertions. In fact, we have a great lack of knowledge about the diseases, hybridisation problems, trophic competition, etc. that translocated species can bring", highlights the researcher.

Legislative and river management challenge

The conclusions of this study present a considerable challenge for the current legislation and river management, such as, for example, finding oneself in the situation of having to protect and eradicate the same species depending on the hydrological basin in which it is found. Alberto Maceda notes that “Species are usually declared problem species in a political territory, but we can find that a species is native and has invasive populations in the same political area. To make things worse, we may even find that a species is in decline in its native basin, but it is expanding in basins where it has been previously introduced”.

In this context, the researcher points to habitat conservation as the aspect that managers should focus on the most in order to conserve native fish. "In general terms, we think that action should be taken regarding the habitat conservation, because the benefits have multiple dimensions that, on the rebound, can even make native species better competitors against exotic species", he says.

Despite this general recommendation, Alberto Maceda adds that sometimes an intervention against introduced species can also be a solution, especially if they are translocated natives, because they may have similar habitat requirements to natives. "Rivers with poorly conserved habitats also experience the most biological invasions, and it is often difficult to distinguish between the effects of exotic species and habitat. However, in some cases the main detrimental effect is that of translocated native or exotic species, and therefore acting on them, if a complete eradication is feasible, will certainly be beneficial to the river", he concludes.

JOURNAL

Science of The Total Environment

DOI

10.1016/j.scitotenv.2022.155953

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

“Patterns of species richness, abundance and individual-size distributions in native stream-fish assemblages invaded by exotic and translocated fishes

SOLITARY IS TORTURE

Rates of solitary confinement of incarcerated people with mental illness three times higher than those without mental illness

Peer-Reviewed Publication

AMERICAN SOCIETY OF CRIMINOLOGY

Harsh prison conditions, including solitary confinement, affect the mental health of incarcerated people. But few studies have considered how the criminalization of mental health status contributes to harsh treatment in the criminal justice system. A new study examined inequities in the incidence and duration of solitary confinement by mental health status. The study found high rates of punitive isolation among those with serious mental illness, with a three times higher rate of solitary confinement for them than for similar incarcerated people without mental health problems.

The study, by researchers at Boston University, Columbia University, and Harvard University, appears in Criminology, a publication of the American Society of Criminology.

“With people in prison confined to their cells for up to 23 hours a day, often denied visitors and phone calls, solitary confinement is an important test case for studying harsh treatment in prisons,” says Jessica T. Simes, assistant professor of sociology at Boston University, who led the study. “Routinely used as punishment for prison infractions, this type of confinement may be subject to the same forces that criminalize people with mental health problems in community settings.”

Researchers analyzed a large administrative dataset that showed all prison admissions and discharges from 2007 to 2016 in Pennsylvania, whose prison population is demographically similar to the national prison population. The study analyzed data for more than 90,000 individuals.

All those entering Pennsylvania prisons for the first time receive a four-day mental health screening at intake. More than half of the men and 18 percent of the women in the study had no prior history of mental illness. More than half of the women and 21 percent of the men had active diagnoses requiring treatment for mental illness. About 11 percent of the women were diagnosed with serious mental illness or intellectual disability; 2 percent of the men were diagnosed with serious mental illness. Similar to the national average, on an average day, 4 percent of the total Pennsylvania prison population was in solitary confinement.

Researchers looked at a classification that indicates the mental health history and treatment needs of people in prison at their first admission. With data on prison misconduct charges and admissions to solitary confinement that result from a charge, they then modelled solitary confinement through the three stages of receiving a ticket written for a charge of misconduct, being sent to solitary confinement, and being sentenced for a given duration, estimating disparities by mental health status at each stage of the disciplinary process, to determine which stage of prison discipline contributes most to overall disparity.

The study found that people with serious mental illness experienced frequent and lengthy periods of solitary confinement, controlling for crime and misconduct histories. The average person in prison with serious mental illness spent three times longer in solitary confinement than a similar person in prison with no history of mental illness.

In addition, disproportionate solitary confinement resulted mostly from the large number of misconduct tickets written by prison staff to mentally ill people in prison, with most tickets for nonviolent misconduct categories of threats and defiance. This highlights the importance of correctional officers at the first stage of the prison disciplinary process, and it suggests that disparities could be reduced by changing the use of discretion through officer training, policy change, or greater oversight.

The study also found that 64 percent of female prisoners had an ongoing mental health diagnosis, putting them at high risk of punitive isolation in prison.

“Our results are consistent with a process of cumulative disadvantage operating in prisons in which the stigma of mental illness affects decisions at each stage of the prison discipline process,” explains Bruce Western, professor of sociology and director of the Justice Lab at Columbia University, who coauthored the study. “The mental health disparities we found, combined with evidence that isolation in incarceration exacerbates mental illness, underline the extreme potential for institutional harm associated with solitary confinement, and show how U.S. prisons heap the harshest forms of punishment on the most vulnerable.”

Among the study’s limitations, the authors note that administrative records provide limited portraits of prison conditions and may underestimate incidences of solitary confinement. In addition, the study observed only the mental health category assigned at intake and did not account for changes in mental health status over time. And it assessed incidents of disciplinary confinement, not administrative segregation (the former is used for punishment while the latter is used to separate the vulnerable and control conflicts among people in prison).

“Although we focused on prisons and the disciplinary process leading to solitary confinement, our findings are relevant to the institutional production of social inequality more generally,” suggests Angela Lee, researcher at Harvard University, who coauthored the study. “Institutionalized power relations—whether in prisons, large corporations, classrooms, the military, or border control facilities—facilitate the effects of stigma and accumulated disparity.”

The study was supported by Arnold Ventures, the Robert Wood Johnson Foundation, the National Science Foundation, the Project on Race, Class, and Cumulative Adversity at Harvard University funded by the Ford Foundation and the Hutchins Family Foundation, the Justice and Poverty Project funded by the Ford Foundation, and the Institute for Social and Economic Research and Policy at Columbia University.

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Summarized from Criminology, Mental Health Disparities in Solitary Confinement by Simes, JT (Boston University), Western, B (Columbia University), and Lee, A (Harvard University). Copyright 2022 The American Society of Criminology. All rights reserved.

JOURNAL

Criminology

New study challenges old views on what’s ‘primitive’ in mammalian reproduction

Peer-Reviewed Publication

UNIVERSITY OF WASHINGTON

Multituberculate mother and pups — IMAGE: AN ARTISTIC RENDERING OF MULTITUBERCULATES FROM THE GENUS MESODMA — A MOTHER WITH HER LITTER OF OFFSPRING — WHO LIVED IN WESTERN NORTH AMERICA ABOUT 60 TO 70 MILLION YEARS AGO. FOSSIL EVIDENCE INDICATES THAT THESE CREATURES WERE THE MOST ABUNDANT MAMMALS IN WESTERN NORTH AMERICA JUST BEFORE AND DIRECTLY AFTER THE MASS EXTINCTION EVENT 66 MILLION YEARS AGO THAT KILLED OFF THE DINOSAURS. view more
CREDIT: ANDREY ATUCHIN

Link to Google Drive folder containing images and caption/credit information:

https://drive.google.com/drive/folders/1mQN6VLwXhCt6jUIaQnY9AJ7E6146WlfV?usp=sharing

It’s hard to imagine life on Earth without mammals. They swim in the depths of the ocean, hop across deserts in Australia and travel to the moon.

This diversity can be deceiving, at least when it comes to how mammals create the next generation. Based on how they reproduce, nearly all mammals alive today fall into one of two categories: placental mammals and marsupials. Placentals, including humans, whales and rodents, have long gestation periods. They give birth to well-developed young — with all major organs and structures in place — and have relatively short weaning periods, or lactation periods, during which young are nursed on milk from their mothers. Marsupials, like kangaroos and opossums, are the opposite: They have short gestation periods — giving birth to young that are little more than fetuses — and long lactation periods during which offspring spend weeks or months nursing and growing within the mother’s pouch, or marsupium.

For decades, biologists saw the marsupial way of reproduction as the more “primitive” state, and assumed that placentals had evolved their more “advanced” method after these two groups diverged from one another. But new research is testing that view. In a paper published July 18 in The American Naturalist, a team led by researchers at the University of Washington and its Burke Museum of Natural History and Culture present evidence that another group of mammals — the extinct multituberculates — likely reproduced in a placental-like manner. Since multituberculates split off from the rest of the mammalian lineage before placentals and marsupials evolved, these findings question the view that marsupials were “less advanced” than their placental cousins.

“This study challenges the prevalent idea that the placental reproductive strategy is ‘advanced’ relative to a more ‘primitive’ marsupial strategy,” said lead author Lucas Weaver, a postdoctoral researcher at the University of Michigan who conducted this study as a UW doctoral student. “Our findings suggest that placental-like reproduction either is the ancestral reproductive route for all mammals that give birth to live young, or that placental-like reproduction evolved independently in both multituberculates and placentals.”

Multituberculates arose about 170 million years ago in the Jurassic. Most were small-bodied creatures, resembling rodents. For much of their history, multituberculates were the most abundant and diverse group of mammals. But scientists know very little about their life history, including how they reproduced, because of their generally poor fossil record. The last multituberculates died out about 35 million years ago.

Weaver reasoned that the microscopic structure of fossilized bone tissues can house useful life-history information about multituberculates, such as their growth rate. Working under co-author Gregory Wilson Mantilla, a UW professor of biology and curator of vertebrate paleontology at the Burke Museum, Weaver and his colleagues obtained cross sections of 18 fossilized femurs — the thigh bone — from multituberculates that lived approximately 66 million years ago in Montana.

All 18 samples showed the same structural organization: a layer of disorganized bone “sandwiched” between an inner and outer layer of organized bone. Disorganized bone, or woven bone, indicates rapid growth and is so named because, under a microscope, the layers of bone tissue are laid out in a crisscrossed fashion. In organized bone, which reflects slower growth, layers are parallel to one another.

The researchers then examined femoral cross sections taken from 35 small-bodied mammalian species that are living today — 28 placentals and seven marsupials, all from Burke Museum collections. Nearly all of the placental femurs showed the same “sandwich” organization as the multituberculates. But all of the marsupial femurs consisted almost entirely of organized bone, with only a sliver of disorganized bone.

CAPTION

The three images are cross sections of femurs from a marsupial (the Virginia opossum, left), a placental (the eastern chipmunk, center) and a 66-million-year-old multituberculate fossil (right). The opossum femur has a thick layer of organized bone in the outermost cortex (labeled “POB” for periosteal organized bone), with little disorganized bone (labeled “DB”). In the chipmunk and multituberculate femurs, a layer of disorganized bone (“DB”) is “sandwiched” between layers of organized bone (“POB” and “EOB,” which stands for endosteal organized bone). Scale bar is 0.1 millimeters. The multituberculate specimen (UWBM 70536) is likely a member of the genus Mesodma.

CREDIT

Henry Fulghum/Lucas Weaver/University of Washington

The team believes that this stark difference likely reflects their divergent life histories.

“The amount of organized bone in the outermost layer, or cortex, of the femur strongly correlates with the length of the lactation period,” said Weaver. “Marsupials have long lactation periods and a lot of organized bone in the outermost cortex. The opposite is true for placentals: a short lactation period and much less organized bone in the outermost cortex.”

The outermost layer of organized bone was laid down after birth as the femur’s diameter increased. For tiny marsupial newborns, bones must grow much more to reach adult size, so they deposit a greater amount of outer organized bone compared to placentals, according to Weaver.

“This is compelling evidence that multituberculates had a long gestation and a short lactation period similar to placental mammals, but very different from marsupials,” said Weaver.

Based on this correlation, the researchers estimate that multituberculates had a lactation period of approximately 30 days — similar to today’s rodents.

These findings cast further doubt on an old view that marsupials have a “more primitive” and placentals a “more advanced” reproductive strategy. The common ancestor of multituberculates, placentals and marsupials may have had a placental-like mode of reproduction that was retained by placentals and multituberculates. Alternatively, multituberculates and placentals could have evolved their long-gestation and short-lactation reproductive methods independently.

Future studies of multituberculate life history may clarify which explanation is true, as well as other outstanding questions of this, and other, ancient branches of our mammalian family tree.

“The real revelation here is that we can cut open fossil bones and examine their microscopic structures to reconstruct the intimate life history details of long-extinct mammals,” said Wilson Mantilla. “That’s really incredible to me.”

Additional co-authors are former UW undergraduate researcher Henry Fulghum, now a graduate student at Indiana University; UW postdoctoral researcher David Grossnickle; UW graduate students William Brightly and Zoe Kulik; and Megan Whitney, a UW doctoral alum and current postdoctoral researcher at Harvard University. The research was funded by the National Science Foundation, the UW, the Burke Museum, the Society of Vertebrate Paleontology, the Paleontological Society and the American Society of Mammalogists.

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JOURNAL

The American Naturalist

DOI

10.1086/720410

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animal tissue samples

ARTICLE TITLE

Multituberculate Mammals Show Evidence of a Life History Strategy Similar to That of Placentals, Not Marsupials

ARTICLE PUBLICATION DATE

18-Jul-2022

For dairy farmers, where does the time go?

A new study in the July Journal of Dairy Science® examines labor time-use on pasture-based dairy farms in Ireland

Peer-Reviewed Publication

ELSEVIER

For dairy farmers, where does the time go? — IMAGE: THE LABOR-TRACKING SMARTPHONE APP USED TO STUDY TIME USE ON IRISH PASTURE-BASED DAIRY FARMS IN 2019. view more
CREDIT: CONOR HOGAN, TEAGASC ANIMAL & GRASSLAND RESEARCH & INNOVATION CENTRE, IRELAND

Philadelphia, July 25, 2022 – Globally, dairy producers face increasing challenges regarding sustainability, including declining numbers of workers in the agricultural sector, while continuing to meet increasing demand for nutritious and affordable food. Dairy systems must now focus on more sustainable production that reflects economic, environmental, and social goals. A new report in the Journal of Dairy Science®, published by Elsevier, explores labor time-use on Irish pasture-based dairy farms in the busy spring and summer seasons.

Employment in agriculture, as a share of total worldwide employment, has declined by 29.8% since the year 2000. Due to this reduced availability of workers, management of labor input is becoming a crucial challenge for dairy farms internationally, especially in expanding dairy markets. The seasonal workload associated with pasture-based dairy farming—a system that promotes farm profitability along with favorable environmental impacts—combined with increasing herd sizes, has led to a renewed focus on labor time-use and efficiency on these farms.

The study used up-to-date technology, including a mobile phone app, to track labor time-use across 82 spring-calving pasture-based Irish dairy farms from February 1 to June 30, 2019. This allowed the research team to begin examining the often-overlooked social dimension of sustainable farming, including working hours and quality of life.

First author Conor Hogan, of Teagasc Animal & Grassland Research & Innovation Centre (Moorepark, Fermoy, County Cork, Ireland) and the School of Agriculture and Food Science, University College Dublin (Dublin, Ireland), explains, “Each farmer recorded their labor input on one alternating day each week, using a smartphone app. Any labor input by farm workers not using the app was recorded through a weekly online survey.”

The team found that milking was the most time-consuming task, representing 31% of farm labor input, making it an important focus for potential improvements in efficiency. The next most time-consuming tasks were calf care (14%), grassland management (13%), cow care (10%), repairs and maintenance (10%), and administration/business (8%). The researchers further report that participating farmers worked, on average, 60 hours a week across the study period, and that the busiest months on most of the farms were February and March.

The team emphasizes the importance of understanding labor use during the most labor-demanding time of year on pasture-based dairy farms, as this points to areas where labor efficiency improvements can be made. As Hogan points out, “Improved time-use in spring and summer, resulting in reduced work hours, can have associated positive effects on many aspects of dairy farming, including enhanced health and safety of farm operators and reduced stress and fatigue among farmers, creating more attractive workplaces and improving farm profitability.”

JOURNAL

Journal of Dairy Science

DOI

10.3168/jds.2022-21935

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

An examination of labor time-use on spring-calving dairy farms in Ireland

Study refutes claim that T. rex was three separate species

Paleontologists find insufficient evidence that iconic Tyrannosaurus rex should be reclassified

Peer-Reviewed Publication

AMERICAN MUSEUM OF NATURAL HISTORY

T. rex model — IMAGE: AS PART OF THE MUSEUM’S TEMPORARY EXHIBITION T. REX: THE ULTIMATE PREDATOR, WHICH WAS ON VIEW FROM 2019-2021, VISITORS ENCOUNTERED A MASSIVE LIFE-SIZED MODEL OF T. REX WITH PATCHES OF FEATHERS—THE MOST SCIENTIFICALLY ACCURATE REPRESENTATION OF T. REX TO DATE. view more
CREDIT: D. FINNIN/ ©AMNH

A new study refutes a provocative claim made earlier this year that fossils classified as the dinosaur Tyrannosaurus rex represent three separate species. The rebuttal, published today in the journal Evolutionary Biology and led by paleontologists at the American Museum of Natural History and Carthage College, finds that the earlier proposal lacks sufficient evidence to split up the iconic species.

“Tyrannosaurus rex remains the one true king of the dinosaurs,” said study co-author Steve Brusatte, a paleontologist at the University of Edinburgh who conducted his Ph.D. work at the Museum. “Recently, a bold theory was announced to much fanfare: what we call T. rex was actually multiple species. It is true that the fossils we have are somewhat variable in size and shape, but as we show in our new study, that variation is minor and cannot be used to neatly separate the fossils into easily defined clusters. Based on all the fossil evidence we currently have, T. rex stands alone as the single giant apex predator from the end of the Age of Dinosaurs in North America.”

In March 2022, authors of the controversial study, also published in Evolutionary Biology, made the case that T. rex should be reclassified as three species: the standard T. rex, the bulkier “T. imperator,” and the slimmer “T. regina.” The study was based on analysis of the leg bones and teeth of 38 T. rex specimens.

The authors of the new study revisited the data presented in the earlier paper and also added data points from 112 species of living dinosaurs—birds—and from four non-avian theropod dinosaurs. They found that the multiple species argument was based on a limited comparative sample, non-comparable measurements, and improper statistical techniques.

“Their study claimed that the variation in T. rex specimens was so high that they were probably from multiple closely related species of giant meat-eating dinosaur,” said James Napoli, co-lead author of the rebuttal study and a graduating doctoral student in the Museum’s Richard Gilder Graduate School. “But this claim was based on a very small comparative sample. When compared to data from hundreds of living birds, we actually found that T. rex is less variable than most living theropod dinosaurs. This line of evidence for proposed multiple species doesn’t hold up.”

“Pinning down variation in long-extinct animals is a major challenge for paleontologists,” said co-lead author Thomas Carr from Carthage College. “Our study shows that rigorous statistical analyses that are grounded in our knowledge of living animals is the best way to clarify the boundaries of extinct species. In practical terms, the three-species model is so poorly defined that many excellent specimens can’t be identified. That’s a clear warning sign of a hypothesis that doesn’t map onto the real world.”

CAPTION

An illustration of a T. rex feeding

CREDIT

The original paper asserted that variation in the size of the second tooth in the lower jaw, in addition to robustness of the femur, indicated the presence of multiple species. But the authors of the new study could not replicate the tooth findings, and they recovered different results from their own measurements of the same specimens. In addition, the authors of the new study took issue with how the “breakpoints” for each species using these traits were statistically determined. The statistical analysis in the original study defined the number of groups before the test was run, so it is not useful for testing the hypothesis, according to the authors of the new study. In the latest study, a different statistical technique was used to determine how many clusters exist within the data without any advanced assumptions, finding that they are best considered as a single group—in other words, one species—T. rex.

“The boundaries of even living species are very hard to define: for instance, zoologists disagree over the number of living species of giraffe,” said co-author Thomas Holtz, from the University of Maryland and the National Museum of Natural History. “It becomes much more difficult when the species involved are ancient and only known from a fairly small number of specimens. Other sources of variation—changes with growth, with region, with sex, and with good old-fashioned individual differences—have to be rejected before one accepts the hypothesis that two sets of specimens are in fact separate species. In our view, that hypothesis is not yet the best explanation.”

“T. rex is an iconic species and an incredibly important one for both paleontological research and communicating to the public about science, so it’s important that we get this right,” said co-author David Hone, from Queen Mary University of London. “There is still a good chance that there is more than one species of Tyrannosaurus out there, but we need strong evidence to make that kind of decision.”

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JOURNAL

Evolutionary Biology

DOI

10.1007/s11692-022-09573-1

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

The Tyrant Lizard King, Queen and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and Probable Speciation Within the North American Genus Tyrannosaurus

ARTICLE PUBLICATION DATE

25-Jul-2022