Saturday, October 12, 2024

 

These 19th century lions from Kenya ate humans, DNA collected from hairs in their teeth shows



Cell Press
Tsavo lion teeth 

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The lions’ teeth had been damaged during their lifetimes. Study coauthor Thomas Gnoske found thousands of hairs embedded in the exposed cavities of the broken teeth. 

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Credit: Field Museum of Natural History in Chicago




By isolating and sequencing DNA in compacted hairs collected from the teeth of two Tsavo lion museum specimens from the 1890s, researchers have found that the historic lions from Kenya preyed on a variety of species, including humans, giraffes, and wildebeests. These so-called “Tsavo Man-Eaters” are estimated to have killed at least dozens of people, including those working along the Kenya-Uganda Railway in the late 1890’s. The findings appear in the Cell Press journal Current Biology on October 11.

“As biotechnologies advance, there are unexpected sources of knowledge, in this case genomics, that can be used to inform about the past,” says Ripan Malhi (@MalhiRipan) of the University of Illinois Urbana-Champaign. “Our results inform on the ecology and diet of lions in the past as well as on the impacts of colonization on life and land in this region of Africa.”

“A key part of this study was to create a method to extract and analyze DNA from single hairs of prey species found in the teeth of historical museum specimens,” says Alida de Flamingh (@adeflamingh), also at the University of Illinois Urbana-Champaign. “Our analysis showed that the historic Tsavo lions preyed on giraffe, human, oryx, waterbuck, wildebeest, and zebra, and we also identified hairs that originated from lions. This method can be used in many ways, and we hope other researchers will apply it to study prey DNA from other animal skulls and teeth.”

Study co-author Tom Gnoske at the Field Museum of Natural History in Chicago was the first to consider reconstructing the diet of these historic lions using prey hairs from their skulls, the researchers say. With collaborators in Kenya, he began to identify the hairs using microscopy. While conducting ancient DNA research on other animals at the Field Museum, the University of Illinois team got the idea to add genomics as a complementary approach to the study of those compacted hairs.

The Tsavo lions in the new study had dental injuries, including partially broken canine teeth exposing cavities where hair from their prey built up over time. From those tooth cavities, the researchers extracted DNA from individual hair shafts and tiny clumps of hair fragments. While the DNA in those samples was degraded in ways that are typical for historic or ancient DNA, they were able to piece enough of it back together in some of the samples to identify the species the hair originated from. They ultimately identified six prey species, including giraffe, human, oryx, waterbuck, wildebeest, and zebra.

The DNA data narrowed the giraffe sample down to a subspecies of Masai giraffe from southeast Kenya. The researchers also found Tsavo lion DNA that most closely matched other East African lions from Kenya and Tanzania. The researchers said they were most surprised to find hair from wildebeest, noting that it raises questions about their distribution in the past.

 “It suggests that the Tsavo lions may have either traveled farther than previously believed, or that wildebeest were present in the Tsavo region during that time,” de Flamingh said. “The closest grazing area for wildebeest was over 50 miles from where the lions were killed in 1898 at the Tsavo-Athi confluence.”

 The researchers say they are excited to explore the findings in even greater detail. For example, they suggest that the layered hairs can allow them to go back in time to reconstruct the lions’ diet at different ages. They suggest that such analysis may offer insight into human-lion conflicts that continue to impact communities in Africa, where lions may prey on wildlife as well as domestic animals and humans. The method also holds promise for studies of even older specimens.

“This methodology can potentially be used on hairs from broken teeth of more ancient carnivores from hundreds to thousands of years ago,” Malhi said. “The method opens up a new avenue of inquiry into the past.”

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This work was supported by the US Department of Agriculture, USAID, and the University of Illinois Urbana-Champaign.

Current Biology, de Flamingh et al. “Compacted hair in broken teeth reveal dietary prey of historic lions” https://cell.com/current-biology/fulltext/S0960-9822(24)01240-5

Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.

Genomic study identifies human, animal hair in ‘man-eater’ lions’ teeth




University of Illinois at Urbana-Champaign, News Bureau
Lion Eyes 

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A new study analyzed hairs embedded in the damaged teeth of two “man-eater” lions that killed at least 28 people in 1898 in the Tsavo region of Kenya.

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Credit: Photo copyright Michael Jeffords and Susan Post




CHAMPAIGN, Ill. — In 1898, two male lions terrorized an encampment of bridge builders on the Tsavo River in Kenya. The lions, which were massive and maneless, crept into the camp at night, raided the tents and dragged off their victims. The infamous Tsavo “man-eaters” killed at least 28 people before Lt. Col. John Henry Patterson, the civil engineer on the project, shot them dead. Patterson sold the lions’ remains to the Field Museum of Natural History in Chicago in 1925.

In a new study, Field Museum researchers collaborated with scientists at the University of Illinois Urbana-Champaign on an in-depth analysis of hairs carefully extracted from the lions’ broken teeth. The study used microscopy and genomics to identify some of the species the lions consumed. The findings are reported in the journal Current Biology.

The original discovery of the hairs occurred in the early 1990s, when Thomas Gnoske, a collections manager at the Field Museum, found the lions’ skulls in storage and examined them for signs of what they had consumed. He was the first to determine that they were fully grown older adult males — despite being maneless. He also was the first to notice that thousands of broken and compacted hairs had accumulated in exposed cavities in the lions’ damaged teeth during their lifetimes.

In 2001, Gnoske and Julian Kerbis Peterhans, a professor at Roosevelt University and Field Museum adjunct curator, first reported on the damaged condition of the teeth — which they hypothesized may have contributed to the lions’ predation of humans — and the presence of hairs embedded in broken and partially healed teeth. A preliminary analysis of some of the hairs suggested that they were from eland, impala, oryx, porcupine, warthog and zebra. 

In the new study, Gnoske and Peterhans facilitated a new examination of some of the hairs. Co-authors Ogeto Mwebi, a senior research scientist at the National Museums of Kenya; and Nduhiu Gitahi, a researcher at the University of Nairobi, conducted the microscopic analysis of the hairs. U. of I. postdoctoral researcher Alida de Flamingh led a genomic investigation of the hairs with U. of I. anthropology professor Ripan S. Malhi. They focused on a separate sample of four individual hairs and three clumps of hairs extracted from the lions’ teeth.

Malhi, de Flamingh and their colleagues are developing new techniques to learn about the past by sequencing and analyzing ancient DNA preserved in biological artifacts. Their work in partnership with Indigenous communities has yielded numerous insights into human migration and the pre- and postcolonial history of the Americas. They have helped develop tools for determining the species and geographic origins of present-day and ancient tusks of African elephants. They have advanced efforts to isolate and sequence DNA from museum specimens and have traced the migration and genomic history of dogs in the Americas.

In the current work, de Flamingh first looked for, and found, familiar hallmarks of age-related degradation in what remained of the nuclear DNA in the hairs from the lions’ teeth.

“To establish the authenticity of the sample we’re analyzing, we look to see whether the DNA has these patterns that are typically found in ancient DNA,” she said.

Once the samples were authenticated, de Flamingh focused on mitochondrial DNA. In humans and other animals, the mitochondrial genome is inherited from the mother and can be used to trace matrilineal lineages through time.

There are several advantages to focusing on mtDNA in hair, the researchers said. Previous studies have found that hair structure preserves mtDNA and protects it from external contamination. MtDNA also is much more abundant than nuclear DNA in cells.

“And because the mitochondrial genome is much smaller than the nuclear genome, it’s easier to reconstruct in potential prey species,” de Flamingh said.

The team built a database of mtDNA profiles of potential prey species. This reference database was compared with mtDNA profiles obtained from the hairs. The researchers took into account the species suggested in the earlier analysis and those known to be present in Tsavo at the time the lions were alive.

The researchers also developed methods for extracting and analyzing the mtDNA from the hair fragments.

“We were even able to get DNA from fragments that were shorter than the nail on your pinky finger,” de Flamingh said.

“Traditionally, when people want to get DNA from hairs, they’ll focus on the follicle, which is going to have a lot of nuclear DNA in it,” Malhi said. “But these were fragments of hair shafts that were more than 100 years old.”

The effort yielded a treasure trove of information. 

“Analysis of hair DNA identified giraffe, human, oryx, waterbuck, wildebeest and zebra as prey, and also identified hairs that originated from lions,” the researchers reported.

The lions were found to share the same maternally inherited mitochondrial genome, supporting early reports theorizing that they were siblings. Their mtDNA also was consistent with an origin in Kenya or Tanzania.

The team found that the lions had consumed at least two giraffes, along with a zebra that likely originated in the Tsavo region.

The discovery of wildebeest mtDNA was surprising because the nearest population of wildebeests in the late 1890s was about 50 miles away, the researchers said. Historical reports, however, noted that the lions left the Tsavo region for about six months before resuming their rampage on the bridge-builders’ camp.

The absence of buffalo DNA and the presence of only a single buffalo hair — identified using microscopy — was surprising, de Flamingh said. “We know from what lions in Tsavo eat today that buffalo is the preferred prey,” she said.

“Colonel Patterson kept a handwritten field journal during his time at Tsavo,” Kerbis Peterhans said. “But he never recorded seeing buffalo or indigenous cattle in his journal.”

At the time, the cattle and buffalo populations in this part of Africa were devastated by rinderpest, a highly contagious viral disease brought to Africa from India by the early 1880s, Kerbis Peterhans said.

“It all but wiped out cattle and their wild relatives, including cape buffalo,” he said.

The mitogenome of the human hair has a broad geographic distribution and the scientists declined to describe or analyze it further for the current study.

“There may be descendants still in the region today and to practice responsible and ethical science, we are using community-based methods to extend the human aspects of the larger project,” they wrote.

The new findings are an important expansion of the kinds of data that can be extracted from skulls and hairs from the past, the researchers said.

“Now we know that we can reconstruct complete mitochondrial genomes from single hair fragments from lions that are more than 100 years old,” de Flamingh said.

There were thousands of hairs embedded in the lions’ teeth, compacted over a period of years, the researchers said. Further analyses will allow the scientists to at least partially reconstruct the lions’ diet over time and perhaps pinpoint when their habit of preying on humans began.

Malhi also is an affiliate of the Carl R. Woese Institute for Genomic Biology at the U. of I.

The National Science Foundation and U.S. Department of Agriculture supported this research.

A genomic study of the maneless Tsavo lions confirmed that they were likely siblings. Pictured: a pair of maneless lions living today in the Tsavo region.  

The lions’ teeth were damaged during their lifetimes. Study co-author Thomas Gnoske found thousands of hairs embedded in the exposed cavities of the broken teeth.

Credit

Photo Z94320 courtesy Field Museum of Natural History in Chicago

Hairs embedded in the lions’ teeth included those of zebra, top, and wildebeest, bottom.  

The study also identified hairs from two giraffes in the lions’ teeth.

Credit

Painting copyright Velizar Simeonovski, 2024


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In the 1990s, a team from the Kenya Wildlife Service and the Field Museum of Natural History in Chicago found a cave that the “man-eater” lions had used in Tsavo, Kenya. The team included Thomas Gnoske, front row, far left; Julian Kerbis Peterhans, front row, far right; and Samuel Andanje, back row, second from left, a KWS research biologist who, with Gnoske and Kerbis Peterhans, coordinated the search for the cave.

Credit

Photo © Thomas Gnoske, 1997

 

Editor’s notes


The paper “Compacted hair in broken teeth reveal dietary prey of historic lions” is available online or from the U. of I. News Bureau.

Michael Jeffords and Susan Post are wildlife photographers, authors and research affiliates of the Illinois Natural History Survey at the Prairie Research Institute of the U. of I. Their photographs are available here


 

New study reveals key actors in global transshipment, boosting seafood transparency




Stockholm Resilience Centre
Press image Frida Bengtsson 

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Frida Bengtsson, researcher at Stockholm Resilience Centre at Stockholm University

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Credit: Johannes Ernstberger/Stockholm Resilience Centre




Fish taxies – refrigerated cargo vessels or reefers that function as mobile ports for fishing boats – are frequently described as weak links in the traceability of the seafood value chain. For the first time, new research has identified the owners of all globally used reefers, the flags they use, and the fishing vessels they meet. The new article, published today in Science Advances, shows that only 324 owners are responsible for all transshipment of fish worldwide, with China, Russia and Greece playing a significant role. “A major step for more transparency,” says lead author Frida Bengtsson of the Stockholm Resilience Centre at Stockholm University.

Refrigerated cargo vessels— or “reefers”—play a significant role in the seafood industry. For instance, nearly a third of global tuna catch (worth US$10.4 billion) is transhipped annually. Transshipment, the transfer of catches but also people, spare parts and fuel between a fishing vessel and a reefer, has been repeatedly described as opaque and associated with illegal activities, as it can enable the transfer of illegally caught species or obscure the origin of seafood.

Fishing practices at sea used to be out of sight and out of mind, but recent advancements in the collection and sharing of satellite data at the vessel level mean that researchers and the public can now see where vessels operate. A missing piece, however, has been knowing who owns the reefer vessels used in the transshipment of seafood.

“Understanding who the beneficial owner of a vessel is provides new leverage and opportunity for improved governance and oversight of this practice,” explains Frida Bengtsson, the study's lead author.

In this study, researchers from the Stockholm Resilience Centre, the Stanford Center for Ocean Solutions and the University of British Columbia have identified 569 reefers currently in use in the fishing industry and their 324 beneficial owners. Just ten of these owners account for almost a quarter of all transshipment events globally. Considering the volumes of seafood that are transshipped, this is a surprisingly low and very manageable number of actors, explains Frida Bengtsson:

“If we work with these key actors and get them to improve their operations, we could quickly improve the traceability and sustainability of seafood.”

The new research has also mapped where in the ocean reefer owners operate their vessels, the gear used by the fishing vessels they meet, and the flags involved. All this data can now be freely accessed and visualised using an online tool. This unprecedented transparency can become a key tool for NGOs, insurance companies, and financial actors interested in creating stronger incentives for sustainable behaviours at sea.

 

How did the building blocks of life arrive on Earth?




University of Cambridge

How did the building blocks of life arrive on Earth? 

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An iron meteorite from the core of a melted planetesimal (left) and a chondrite meteorite, derived from a ‘primitive’, unmelted planetesimal (right).

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Credit: Rayssa Martins/Ross Findlay





Researchers have used the chemical fingerprints of zinc contained in meteorites to determine the origin of volatile elements on Earth. The results suggest that without ‘unmelted’ asteroids, there may not have been enough of these compounds on Earth for life to emerge.

Volatiles are elements or compounds that change into vapour at relatively low temperatures. They include the six most common elements found in living organisms, as well as water. The zinc found in meteorites has a unique composition, which can be used to identify the sources of Earth’s volatiles.

The researchers, from the University of Cambridge and Imperial College London, have previously found that Earth’s zinc came from different parts of our Solar System: about half came from beyond Jupiter and half originated closer to Earth.

“One of the most fundamental questions on the origin of life is where the materials we need for life to evolve came from,” said Dr Rayssa Martins from Cambridge’s Department of Earth Sciences. “If we can understand how these materials came to be on Earth, it might give us clues to how life originated here, and how it might emerge elsewhere.”

Planetesimals are the main building blocks of rocky planets, such as Earth. These small bodies are formed through a process called accretion, where particles around a young star start to stick together, and form progressively larger bodies.

But not all planetesimals are made equal. The earliest planetesimals that formed in the Solar System were exposed to high levels of radioactivity, which caused them to melt and lose their volatiles. But some planetesimals formed after these sources of radioactivity were mostly extinct, which helped them survive the melting process and preserved more of their volatiles.

In a study published in the journal Science Advances, Martins and her colleagues looked at the different forms of zinc that arrived on Earth from these planetesimals. The researchers measured the zinc from a large sample of meteorites originating from different planetesimals and used this data to model how Earth got its zinc, by tracing the entire period of the Earth’s accretion, which took tens of millions of years.

Their results show that while these ‘melted’ planetesimals contributed about 70% of Earth’s overall mass, they only provided around 10% of its zinc.

According to the model, the rest of Earth’s zinc came from materials that didn’t melt and lose their volatile elements. Their findings suggest that unmelted, or ‘primitive’ materials were an essential source of volatiles for Earth.

“We know that the distance between a planet and its star is a determining a factor in establishing the necessary conditions for that planet to sustain liquid water on its surface,” said Martins, the study’s lead author. “But our results show that there’s no guarantee that planets incorporate the right materials to have enough water and other volatiles in the first place – regardless of their physical state.”

The ability to trace elements through millions or even billions of years of evolution could be a vital tool in the search for life elsewhere, such as on Mars, or on planets outside our Solar System.

“Similar conditions and processes are also likely in other young planetary systems,” said Martins. “The roles these different materials play in supplying volatiles is something we should keep in mind when looking for habitable planets elsewhere.”

The research was supported in part by Imperial College London, the European Research Council, and UK Research and Innovation (UKRI).

 

Telescopes can help bring renewable energy to isolated Chilean communities



Utrecht University





Just published research in Nature Sustainability shows that building a renewable energy system for a telescope in Chile’s isolated Atacama Desert could also cover 66% of a nearby community’s energy needs, giving hope for win-win development around other remote infrastructure projects.

Integrating renewable energy sources into the design of the AtLAST telescope would introduce the astronomical community on the Chajnantor plateau and the nearby residential areas to more sustainable energy systems. This integration would reduce local reliance on fossil fuels and provide renewable energy. 

The research shows that replicating similar energy systems at nearby telescopes could reduce fossil fuel-based energy generation by 30GWh annually, cutting emissions by 18-24 kilotonnes of carbon dioxide equivalent while contributing to access to affordable renewable energy for surrounding communities.

Remote astronomical facilities

Home to observatories like the Atacama Pathfinder Experiment (APEX) and the Atacama Large Millimeter/submillimeter Array (ALMA), the Chajnantor plateau in the Atacama Desert, Chile is a global astronomical prime spot. Due to their remoteness, astronomical facilities are often disconnected from the national electricity grid and rely on diesel and gas generators to supply their power-intensive operations. 

Atacama Desert a prime location for solar energy

The Atacama Desert is also a prime location for solar energy projects, holding the highest levels of solar irradiation globally. However, although the area hosts 85% of Chile’s solar energy developments, Atacameños pay more for their energy than the capital region. For example, the national electricity grid ends 100km from San Pedro de Atacama, which besides Patagonia is one of the most prominent tourist destinations in Chile. The town and its surrounding areas operated solely diesel and natural gas generators until 2022 and suffer frequent power outages. Most renewable energy generated in the region is used to power lithium mines and exported to other provinces.

The researchers identified the feasibility of using surplus energy from the AtLAST telescope’s energy system to supply San Pedro de Atacama. “A solar renewable energy system sized to supply the telescope could cover 66% of the electricity demand of San Pedro de Atacama without additional capacities in PV or battery,” says co-author Luis Ramirez Camargo, an assistant professor at Utrecht University’s Copernicus Institute of Sustainable Development.

Energy communities 

This idea is based on “energy communities”, a union of public, private and commercial entities that jointly invest in or share energy infrastructure or provide energy services, and builds on open and fair decision-making.

The researchers created spaces where local residents and other affected parties could share their take on the challenges and opportunities for a more sustainable energy system in the San Pedro de Atacama area. “Allowing those who are truly affected to participate in the discussion and be able to influence decision-making is essential to arrive at just, locally applicable solutions for the energy transition,” says lead author Guillermo Valenzuela Venegas, a researcher at the University of Oslo.

“Distributing benefits to multiple stakeholders through an energy community can lead to a more socially accepted and just energy transition,” says Ramirez Camargo. “Our research shows that astronomy can lead by example in the urgent transition to an equitable net-zero world, keeping our planet habitable and ensuring no one is left behind”.

 

UNH helps community document skeletal remains found on historic ‘poor farm’



Partners with town of Brentwood and state officials to return remains to original resting place




University of New Hampshire

Reburial of remains from historic poor house 

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The remains from the poor house were buried in a simple worrdne box crafted by a local cabinet shop that was inscribed with “Here lies remains only known to God, Brentwood Poor Farm, circa 1841 – 1968”.

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Credit: Robbin Ray / UNH




DURHAM, N.H.—(October 10, 2024)— On a bright autumn afternoon, a plain wooden box crafted by a local cabinet shop containing skeletal remains was returned to its final resting place during a simple reburial ceremony in Brentwood. Researchers and students from the University of New Hampshire’s Forensic Anthropology Identification and Recovery (F.A.I.R.) Lab worked for two years with town officials and the New Hampshire state archaeologist to investigate and document the remains, which were uncovered more than 20 years ago during construction and were identified as being from a farm for paupers during the mid-1800’s, commonly known as a poor farm.

“We analyzed the skeletal remains to determine their age and condition and help solve the mystery of why they were buried in the remote area in an unmarked grave,” said Alex Garcia-Putnam, co-director of UNH’s F.A.I.R. Lab. “After several years of documenting the skeletal remains, we were honored to not only provide valuable information about their lives but to also have the rare opportunity to be present at the reburial— to put these individuals at peace and offer all interested parties some sense of closure.”

The remains of the farm workers were mistakenly uncovered during excavation on private property in 1999. The New Hampshire state archaeologist was called to the site and determined that the remains were historic due to their age and condition and they were transferred to the New Hampshire medical examiner’s office for storage, where they remained for 23 years. In 2022, the remains were transferred to UNH where researchers went to work on skeletal analysis.

UNH’s F.A.I.R. Lab works with law enforcement and the state’s medical examiner’s office to help identify remains. In this case, the work was more historical in nature and the team evaluated the bones to date them and determine the health of the individuals as well as sift through town records and maps to learn more about the historical significance of the area where the remains were found. According to their research, which is chronicled in a paper in the journal of American Antiquity, the remains showed signs of hardship, such as poverty and hard labor and left signs of several health issues like osteoarthritis, dental disease and other signs of physiological stress. The remains were originally found in a grave without any markers—another indication of poverty—on land that was thought to formerly be the Brentwood Poor Farm from 1841 to 1868.

Poor farms were institutions set up as a type of welfare in rural counties in the United States during the 19th and early 20th century to provide support for the poor and other groups of dependent residents. The farms were set up to offer room and board in exchange for labor but the treatment of residents was often exploitive and violent. It is said that poor farms were started to keep marginalized individuals—including a mix of poverty, race, ethnicity and mental or physical illness—out of view of the middle and upper classes.

The town of Brentwood worked closely with the current landowners to set up a reinterment

in the precise location of the original grave. The paupers at the farm were most likely buried in hasty unmarked graves and their final resting place was forgotten over time as the poor farm model for social welfare was dissolved in the 1930s and 1940s and the land passed into private ownership.  

"All individuals deserve a respectful final burial and we hope that this event shows that Brentwood cares about its residents,” said Joyce Keegal, superintendent of cemeteries in Brentwood. “We are so thankful for the work done by UNH to not only help shed light on the lives of these individuals but to also help us advocate for them.”

“This has been an amazing community collaboration by the town of Brentwood, the state, the homeowners and UNH to not only provide answers and connect the threads but also bring closure and meaningful resolutions for all involved,” said Amy Michael, co-director of UNH’s F.A.I.R. lab. “We work on all kinds of investigations—criminal to cold cases—and it is so fulfilling to move someone from a shelf in a medical examiner’s office humanizing them by giving them a dignified burial. Today was a good day.”

The burial site is on private property in an undisclosed area. Plans are in place by Brentwood town officials and historical society for a future exhibit about the Brentwood Poor Farm.

PHOTOS AVAILABLE FOR DOWNLOAD

 

Link: https://www.unh.edu/unhtoday/sites/default/files/eulogy_2_high_res.jpg

Caption: Faculty and students from UNH’s F.A.I.R. Lab reflect during a eulogy given by Albert Edward Belanger, Brentwood cemetery trustee, at the reburial of skeletal remains from the mid-1800’s. The UNH team worked for two years with town officials and the New Hampshire state archaeologist to investigate and document the remains identified as being from the Brentwood Poor Farm which existed from 1841 to 1868.

Photo Credit: Robbin Ray/UNH

 

Link: https://www.unh.edu/unhtoday/sites/default/files/cu_inscription_high_res.jpg

Caption: A local cabinet shop donated their time to craft a simple wooden box for the poor farm remains that was inscribed with “Here lies remains only known to God, Brentwood Poor Farm, circa 1841 – 1968”.

Photo Credit: Robbin Ray/UNH

 

Link: https://www.unh.edu/unhtoday/sites/default/files/group_shot_high_res.jpg

Caption: UNH  F.A.I.R. Lab team and state archaeologist who helped document the remains. From left to right, Mark Doperalski, N.H. state archaeologist; Amy Michael, co-director of UNH F.A.I.R. Lab; Isabella Thomson (’24); Ella Tartsa (’25), UNH F.A.I.R. Lab manager; Alex Garcia-Putnam, co-director of UNH F.A.I.R. Lab; and Ashanti Maronie (’23).

Photo Credit: Robbin Ray/UNH

 

Link: https://www.unh.edu/unhtoday/sites/default/files/reburial_high_res.jpg

Caption: Alex Garcia-Putnam, co-director of UNH’s F.A.I.R. Lab, places the box of remains from the Brentwood Poor Farm (1841 – 1968) in its final resting place.

Photo Credit: Robbin Ray/UNH

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About UNH
The University of New Hampshire inspires innovation and transforms lives in our state, nation and world. More than 16,000 students from 50 states and 87 countries engage with an award-winning faculty in top-ranked programs in business, engineering, law, health and human services, liberal arts and the sciences across more than 200 programs of study. A Carnegie Classification R1 institution, UNH partners with NASA, NOAA, NSF, and NIH, and received over $210 million in competitive external funding in FY23 to further explore and define the frontiers of land, sea and space.


Extreme heat may substantially raise mortality risk for people experiencing homelessness




A new study found that deaths among unhoused people in two major West Coast cities were 10 to 100 times greater than heat-attributable deaths among the general population



Boston University School of Public Health




FOR IMMEDIATE RELEASE

Thursday, October 10, 2024

By nature of their living situation, people experiencing homelessness (PEH) are considered one of the most vulnerable populations to the health impacts of extreme weather.

PEH are particularly vulnerable to heat, and the impact of heat on mortality in this group is substantially greater than for the general population, according to a new study by Boston University School of Public Health (BUSPH).   

Published in the American Journal of Epidemiology, the study examined mortality rates in two hot-climate US counties—Clark County in Nevada, which includes Las Vegas, and Los Angeles County in California—and found that daily heat played a significant role in mortality among PEH.

This association was especially notable in Clark County, where nearly 50 percent of deaths during the study period were attributable to higher daily temperatures. Although LA County observed a smaller percentage of heat-attributable deaths, at 5.2 percent, daily heat appeared to contribute to many more deaths than daily cold in both counties.

The study is the first to examine heat-attributable mortality among PEH, providing valuable public health insight as the West Coast reels from an unprecedented October heatwave that has prompted numerous heat alerts in parts of LA and Las Vegas, where temperatures soared to 111 degrees and 104 degrees, respectively, in recent days. Both cities also continue to grapple with persistently high homelessness rates that far exceed the national average. Quantifying the impacts of extreme heat on PEH can inform new interventions and policies that reduce illness and mortality rates among this largely unsheltered population.

“It wasn’t a surprise that our team found an association between heat and mortality for unhoused people, but the magnitude was staggering,” says study senior and corresponding author Dr. Jonathan Jay, assistant professor of community health sciences at BUSPH. “Our estimates are 10 to 100 times greater than the known associations between daily heat and mortality for the general population in LA and Las Vegas, and this finding highlights the moral imperative for our systems to do more.”

He says the new findings also show that heat exposure is an important factor amplifying the vast health inequities for PEH, and highlight the need to center the most marginalized populations in research on climate and health.

For the study, Dr. Jay and colleagues from BUSPH and the David Geffen School of Medicine at the University of California, Los Angeles utilized mortality and daily temperature data for Clark and Los Angeles counties from January 2015 to August 2022 (for Clark County) and November 2022 (for LA County). The team analyzed deaths from all causes, rather than just deaths that were acutely heat- or cold-related (such as fatal heat stroke or hyperthermia), to ensure that the analysis captured all external causes of death as a result of high temperatures. Hot weather was defined as daily temperatures above the minimum mortality temperature (MMT)—the temperature at which mortality risk is lowest in each area—which was 11.6 Celsius (52.8 degrees Fahrenheit) for Clark County and 19.3 Celsius for LA County (66.7 degrees Fahrenheit).

After accounting for long-term and seasonal trends, days of the week, and cumulative effects of consecutive days’ temperatures, the researchers found that mortality risk among PEH increased in both hotter and colder temperatures. The heat was especially harmful in Clark County, where 15 percent of deaths were due to acutely heat-related causes, compared to 0.2 percent in LA County. Extremely hot days accounted for nearly 25 percent of all deaths in Clark County and 2.2 percent of all deaths in LA County.

“It was important to see that deaths increased as daily temperatures increased, from cool days to warmer days, and they spiked on hotter days, starting around 90 degrees Fahrenheit and higher,” Dr. Jay says. “That’s hot, but it’s not even close to the hottest temperatures these cities experience,” he adds, which suggests that public health advocates should be extra vigilant in providing heat-related support beyond the summer season, as climate change continues to extend the number and length of heat waves each year.

Public health strategies that can mitigate heat impacts among PEH in communities include cooling centers, water stations, greening, and reflective painting, the researchers say. But, ultimately, these strategies should embrace a “Housing First” approach, as the primary cause of homelessness is a lack of affordable housing. California, in particular, is consistently ranked as one of the most expensive states to live in the US. Policies that promote stable housing and other financial support for PEH are even more critical following the Supreme Court’s ruling in June that permits cities to ban people from sleeping and camping in public places.

“Too much of our policy is driven by the impulse to hide homelessness from view, rather than to recognize people’s dignity, protect their health, and improve our systems,” says Dr. Jay. “The idea that policing is key to solving this problem is false, and it’s a miscalculation we make over and over again as a society.”

The lead author of the study is Dr. Zihan Lin, a BUSPH postdoctoral fellow at the time of the study and a current assistant professor of biological, geographical and environmental sciences at Cleveland State University.

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About Boston University School of Public Health

Founded in 1976, Boston University School of Public Health is one of the top ten ranked schools of public health in the world. It offers master's- and doctoral-level education in public health. The faculty in six departments conduct policy-changing public health research around the world, with the mission of improving the health of populations—especially the disadvantaged, underserved, and vulnerable—locally and globally.