A new record for California’s highest tree

Highest Jeffrey pines ever recorded reflect a warming climate in the High Sierra

University of California - Davis

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Sandwiched between a lodgepole pine on the left and a foxtail pine on the right is the first Jeffrey pine tree UC Davis Professor Hugh Safford observed in September 2024 on a hike on the south slope of Mount Kaweah. Lodgepole and foxtail pine are commonly found above timberline, but the Jeffrey stood out as “not belonging there.”

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Credit: Hugh Safford, UC Davis

UC Davis Professor Hugh Safford was hiking for pleasure in California’s High Sierra when he stumbled upon a new elevation record for the Jeffrey pine, which may now be the state’s highest-altitude tree. His serendipitous finding is published in Madroño, a journal of the California Botanical Society.

Last September, at timberline along the south slopes of Mount Kaweah in Sequoia National Park, Safford paused to admire a foxtail pine, then a lodgepole pine — trees he expected to see at such high elevations.

“Then I thought, ‘What’s that?’” said Safford, a forest ecologist in the UC Davis Department of Environmental Science and Policy. “I walk over, and it’s a Jeffrey pine! It made no sense. What is a Jeffrey pine doing above 11,500 feet?”

The Jeffrey pine grows in upper montane areas throughout the Sierra Nevada and is the most common tree found around Lake Tahoe and Mammoth Lakes. It is not considered a traditional subalpine tree species, which inhabit the most extreme high elevations. Yet, Safford recorded Jeffrey pines as high as 12,657 feet elevation. That is 1,860 feet higher in elevation than the highest Jeffrey pine on record and even higher than lodgepole, limber and foxtail pines.

To date, none of the six traditional subalpine forest species have been collected above 12,034 feet. This suggests the Jeffrey pine is California’s highest tree — at least for the moment. Safford’s work indicates that other species are growing higher than commonly used databases suggest.

The discovery signifies a changing climate amid California’s highest peaks. As snow melts earlier and air temperatures rise, Jeffrey pine seeds are germinating on land they previously found frozen and inhospitable.

Moving on up

During his hike-turned-science-expedition, Safford found and examined 14 Jeffrey pines above 11,800 feet elevation, some of which were at least 20 years old. At least a dozen others were visible, but he was unable to visit them.  He and researchers from his lab will return to the southern Sierra Nevada this summer to further research Jeffrey pines in the subalpine zone and what is driving their movement.

For now, Safford strongly suspects a bird — the Clark’s nutcracker — is lending its well-known, high alpine gardening skills to the task of planting Jeffrey pine trees in the area. Much as this nutcracker does for whitebark pine trees, preliminary evidence suggests the bird carries fleshy Jeffrey pine seeds up the mountain from thousands of feet below, storing them in the High Sierra’s “refrigerator” for an early summer snack. 

Earlier snowmelt and warmer temperatures enable some of these Jeffrey pine seeds to not only germinate but to establish themselves as a new population on the mountain.

Leapfrogging trees

Species attempting to stay ahead of climate changes by moving uphill are doing so far too slowly to keep pace, climate modeling literature suggests. Yet the models do not account for the role of seed dispersals by birds and other species amid shifting windows of ecological opportunity.

“I’m looking at trees surviving in habitats where they couldn’t before, but they’re also dying in places they used to live before,” Safford said. “They’re not just holding hands and walking uphill. This crazy leapfrogging of species challenges what we think we know about these systems reacting as the climate warms.”

Jeffrey pine trees are tolerant of both cold and drought, so while their lives along the slopes of Mount Kaweah are harsh and somewhat unexpected, their persistence is promising, Safford said.

Trees in real life

The discovery underscores a need for scientists to couple powerful technologies with direct observation. The trees Safford encountered were not detected by any available database, artificial intelligence platform, satellite or remote sensing technology.

“People aren’t marching to the tops of the mountains to see where the trees really are,” Safford said. “Instead, they are relying on satellite imagery, which can’t see most small trees. What science does is help us understand how the world functions. In this case, where you see the impacts of climate change most dramatically are at high elevations and high latitudes. If we want our finger on the pulse of how the climate is warming and what the impacts are, that’s where it will be happening first. We just need to get people out there.”

This summer, Safford and his students will be out there, hiking along Mount Whitney, Mount Kaweah and Sequoia-Kings Canyon National Parks, identifying seedlings, measuring and identifying trees, and helping to develop models of accurate elevations to better understand the changing landscape of the High Sierra.

This tree set records for both the highest Jeffrey pine and the highest elevation tree recorded in California. UC Davis Professor Hugh Safford observed and recorded the tree in September 2024 during a casual hike. It is at 3,858 meters, or 12,657 feet elevation. The seedling was 6 years old and 10 inches tall.

This Jeffrey pine is an older specimen, an estimated 25 years old. It is 5 feet, 3 inches tall and was found near timberline. As is common for taller specimens, it has a dead top. Jeffrey pines are just barely hanging on at these elevations, and they are not reproducing. Foxtail and lodgepole pines are less likely to have dead tops.

Credit

Hugh Safford, UC Davis

The Clark’s nutcracker plays a crucial role for high-elevation Western forests. It is well-known for burying tens of thousands of pinecone seeds, some of which germinate to become new trees.

Credit

David Menke, U.S. Fish and Wildlife Service

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Journal

Madroño

DOI

10.3120/0024-9637-72.1.a7 

Method of Research

Observational study

Article Title

NEW ELEVATION RECORDS FOR JEFFREY PINE

 

Negative distractions disrupt ongoing task performance

Novel study represents a new tool that could help characterize the ability to resist everyday distractions

Boston University School of Medicine

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(Boston)— The world is full of distractions, like intrusive memories, worries about the future and reminders of things to do.

 

Sustained attention, the ability to maintain focus on a specific stimulus or task for an extended period without significant lapses in concentration, is a foundational cognitive process that underlies many other cognitive functions, impacts daily functioning and is commonly impaired across a diverse population. While upsetting thoughts and experiences can disrupt one’s ability to focus attention while performing everyday tasks, translating this phenomenon to the laboratory has remained elusive.

 

In a new study, researchers from Boston University Chobanian & Avedisian School of Medicine and VA Boston Healthcare System have shown that when people are sustaining attention, distractions that are upsetting or unpleasant are most likely to disrupt that focus. The researchers hope these findings will assist in treating anxiety and post-traumatic stress disorders.

 

“We found that negative distractions disrupted ongoing task performance as well as impacted  the participants’ mood by making them feel worse,” explained corresponding author Michael Esterman, PhD, principal investigator in the VA’s National Center for PTSD and BU associate professor of psychiatry.

 

Two groups of approximately 60 participants performed a series of tasks (called the gradCPT) requiring them to sustain their visual attention for about 10 minutes without a break, while photos of distractions would sometimes fade in and out in the background on a video monitor. These visual distractions could be upsetting (a crying baby), neutral (a chair), or positive (a smiling baby).

 

The researchers found that when the backgrounds were upsetting, participants were both slower and less accurate at the sustained attention task. After the task was completed, participants were tested for their memory of the background distractor, even though they were told to ignore these distractors. They found the upsetting distractors were remembered better than those that were neutral or positive.

 

“We believe this study will help scientists measure how distractible a person is, what is most distracting to them, and whether those distractions intrude in their memories. We also believe it can open new opportunities to study attention in clinical populations and their neural mechanism alongside brain imaging, both of which are directions we are currently pursuing.”

 

These findings appear online in the journal Behavior Research Methods.

 

Funding for this study was provided by the U.S. Department of Veterans Affairs through a Merit Review Award from the VA Clinical Sciences Research and Development Service (1I01CX002711-01) to J.D and M.E.

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Journal

Behavior Research Methods

DOI

10.3758/s13428-025-02641-2 

Method of Research

Observational study

Subject of Research

People

Article Title

Characterizing the effects of emotional distraction on sustained attention and subsequent memory: A novel emotional gradual onset continuous performance task

Article Publication Date

17-Apr-2025

 

Ghanaian pregnant adolescents and adolescent mothers face significant nutritional challenges impacting their and their infants’ health

New research published in the Journal of Nutrition Education and Behavior highlights key factors and attitudes influencing maternal nutrition and infant feeding practices in Ghana

Elsevier

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Lead investigator Harriet Okronipa, PhD, discusses a new study that explores the nutrition perspectives and attitudes of Ghanaian pregnant adolescents and adolescent mothers. It sheds light on significant challenges, including food insecurity, economic constraints, and cultural influences, that impact the dietary habits and health of young mothers and their infants. Offering insights for researchers, practitioners, and policymakers, it focuses on maternal and child health and nutrition education, especially within socioeconomically disadvantaged communities.

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Credit: Journal of Nutrition Education and Behavior

Philadelphia, April 17, 2025 – A recent study in the Journal of Nutrition Education and Behavior, published by Elsevier, explores the nutrition perspectives and attitudes of Ghanaian pregnant adolescents and adolescent mothers. The study sheds light on significant challenges, including food insecurity, economic constraints, and cultural influences, that impact the dietary habits and health of young mothers and their infants.

Researchers conducted a qualitative, community-based cross-sectional study in nine communities across three municipalities and two districts in Ghana’s Central Region. Using focus group discussions, they gathered insights from 35 participants, including 13 pregnant adolescents and 22 adolescent mothers aged 12 to 19. The study utilized Braun and Clarke’s reflexive thematic analysis framework to identify key themes shaping nutritional choices and challenges.

Lead author Christiana Naa Astreh Nsiah-Asamoah, PhD, University of Cape Coast, Cape Coast, Ghana, explained, “The findings of this study offer insights for researchers, practitioners, and policymakers focused on maternal and child health, especially within socioeconomically disadvantaged communities. For professionals in healthcare and community support roles, the study highlights the importance of creating tailored nutrition education programs that address the specific needs and circumstances of pregnant adolescents and adolescent mothers.”

Five central themes emerged: health and well-being, infant nutrition, dietary habits, nutrition information sources, and social support. The findings revealed that adolescent mothers tend to diverge from recommended practices for infant and young child feeding. Economic limitations often led adolescent mothers to rely on less nutritious street foods, while many found exclusive breastfeeding for six months impractical, opting instead for complementary feeding. Limited access to nutrition education and inconsistent social support further compounded these challenges.

The study highlights the importance of strengthening nutrition education programs, improving access to affordable healthy foods, and enhancing community-based support systems to empower young mothers in making informed dietary decisions.

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Journal

Journal of Nutrition Education and Behavior

DOI

10.1016/j.jneb.2024.12.012) 

Method of Research

Survey

Subject of Research

People

Article Title

Nutrition Perspectives and Attitudes Among Ghanaian Pregnant Adolescents and Adolescent Mothers

 

New study reveals how cleft lip and cleft palate can arise

MIT biologists have found that defects in some transfer RNA molecules can lead to the formation of these common conditions

Massachusetts Institute of Technology

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CAMBRIDGE, MA -- Cleft lip and cleft palate are among the most common birth defects, occurring in about one in 1,050 births in the United States. These defects, which appear when the tissues that form the lip or the roof of the mouth do not join completely, are believed to be caused by a mix of genetic and environmental factors.

In a new study, MIT biologists have discovered how a genetic variant often found in people with these facial malformations leads to the development of cleft lip and cleft palate.

Their findings suggest that the variant diminishes cells’ supply of transfer RNA, a molecule that is critical for assembling proteins. When this happens, embryonic face cells are unable to fuse to form the lip and roof of the mouth.

“Until now, no one had made the connection that we made. This particular gene was known to be part of the complex involved in the splicing of transfer RNA, but it wasn’t clear that it played such a crucial role for this process and for facial development. Without the gene, known as DDX1, certain transfer RNA can no longer bring amino acids to the ribosome to make new proteins. If the cells can’t process these tRNAs properly, then the ribosomes can’t make protein anymore,” says Michaela Bartusel, an MIT research scientist and the lead author of the study.

Eliezer Calo, an associate professor of biology at MIT, is the senior author of the paper, which appears today in the American Journal of Human Genetics.

Genetic variants

Cleft lip and cleft palate, also known as orofacial clefts, can be caused by genetic mutations, but in many cases, there is no known genetic cause.

“The mechanism for the development of these orofacial clefts is unclear, mostly because they are known to be impacted by both genetic and environmental factors,” Calo says. “Trying to pinpoint what might be affected has been very challenging in this context.”

To discover genetic factors that influence a particular disease, scientists often perform genome-wide association studies (GWAS), which can reveal variants that are found more often in people who have a particular disease than in people who don’t.

For orofacial clefts, some of the genetic variants that have regularly turned up in GWAS appeared to be in a region of DNA that doesn’t code for proteins. In this study, the MIT team set out to figure out how variants in this region might influence the development of facial malformations.

Their studies revealed that these variants are located in an enhancer region called e2p24.2. Enhancers are segments of DNA that interact with protein-coding genes, helping to activate them by binding to transcription factors that turn on gene expression.

The researchers found that this region is in close proximity to three genes, suggesting that it may control the expression of those genes. One of those genes had already been ruled out as contributing to facial malformations, and another had already been shown to have a connection. In this study, the researchers focused on the third gene, which is known as DDX1.

DDX1, it turned out, is necessary for splicing transfer RNA (tRNA) molecules, which play a critical role in protein synthesis. Each transfer RNA molecule transports a specific amino acid to the ribosome — a cell structure that strings amino acids together to form proteins, based on the instructions carried by messenger RNA.

While there are about 400 different tRNAs found in the human genome, only a fraction of those tRNAs require splicing, and those are the tRNAs most affected by the loss of DDX1. These tRNAs transport four different amino acids, and the researchers hypothesize that these four amino acids may be particularly abundant in proteins that embryonic cells that form the face need to develop properly.

When the ribosomes need one of those four amino acids, but none of them are available, the ribosome can stall, and the protein doesn’t get made.

The researchers are now exploring which proteins might be most affected by the loss of those amino acids. They also plan to investigate what happens inside cells when the ribosomes stall, in hopes of identifying a stress signal that could potentially be blocked and help cells survive.

Malfunctioning tRNA

While this is the first study to link tRNA to craniofacial malformations, previous studies have shown that mutations that impair ribosome formation can also lead to similar defects. Studies have also shown that disruptions of tRNA synthesis — caused by mutations in the enzymes that attach amino acids to tRNA, or in proteins involved in an earlier step in tRNA splicing — can lead to neurodevelopmental disorders.

“Defects in other components of the tRNA pathway have been shown to be associated with neurodevelopmental disease,” Calo says. “One interesting parallel between these two is that the cells that form the face are coming from the same place as the cells that form the neurons, so it seems that these particular cells are very susceptible to tRNA defects.”

The researchers now hope to explore whether environmental factors linked to orofacial birth defects also influence tRNA function. Some of their preliminary work has found that oxidative stress — a buildup of harmful free radicals — can lead to fragmentation of tRNA molecules. Oxidative stress can occur in embryonic cells upon exposure to ethanol, as in fetal alcohol syndrome, or if the mother develops gestational diabetes.

“I think it is worth looking for mutations that might be causing this on the genetic side of things, but then also in the future, we would expand this into which environmental factors have the same effects on tRNA function, and then see which precautions might be able to prevent any effects on tRNAs,” Bartusel says.

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The research was funded by the National Science Foundation Graduate Research Program, the National Cancer Institute, the National Institute of General Medical Sciences, and the Pew Charitable Trusts.

 

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Journal

American Journal of Human Genetics

DOI

10.1016/j.ajhg.2025.03.017 

Article Title

A non-syndromic orofacial cleft risk locus links tRNA splicing defects to neural crest cell pathologies

Article Publication Date

17-Apr-2025

 

Study: Experimental bird flu vaccine excels in animal models

Proven effective for COVID-19, vaccine platform could be key in responding to evolving bird flu strains

Peer-Reviewed Publication

University at Buffalo

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The illustration, above, shows the experimental bird flu vaccine platform. The H5 and N1 proteins attach via his-tag (teal coil) to cobalt ions (red plug) within the cobalt-porphyrin-phospholipid nanoparticle. PHAD and QS-21 are adjuvants embedded into nanoparticle.

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Credit: University at Buffalo

BUFFALO, N.Y. — A vaccine under development at the University at Buffalo has demonstrated complete protection in mice against a deadly variant of the virus that causes bird flu.

The work, detailed in a study published today (April 17) in the journal Cell Biomaterials, focuses on the H5N1 variant known as 2.3.4.4b, which has caused widespread outbreaks in wild birds and poultry, in addition to infecting dairy cattle, domesticated cats, sea lions and other mammals.

In the study, scientists describe a process they’ve developed for creating doses with precise amounts of two key proteins – hemagglutinin (H5) and neuraminidase (N1) – that prompt the body’s immune system to fight bird flu.

This process – what’s known as a “vaccine platform” – could help set the experimental vaccine apart from the handful of bird flu vaccines approved for human use in the U.S. and Europe which, while effective, have focused almost entirely on H5 and not N1.

It’s also a potential step toward more potent, versatile and easy-to-produce vaccines that public health officials believe will be needed to counteract evolving bird flu strains that grow resistant to existing vaccines.

“We obviously have a lot more work to do, but the results thus far are extremely encouraging,” says the study’s lead author Jonathan Lovell, PhD, professor in the Department of Biomedical Engineering at UB.

Tests show vaccine provides complete protection

Lovell and colleagues tested the vaccine platform in mice with 2.3.4.4b. They used doses containing H5 alone, N1 alone, and H5 and N1 combined. They found that:

• H5 alone provided complete protection, with no signs of illness, weight loss nor detectable virus in the lungs.
• N1 alone gave partial protection. It was roughly 70% effective, with some mice showing symptoms and viral presence.
• H5 and N1 together, which is a bivalent vaccine, also provided complete protection, but it did not outperform H5 alone. Put another way, adding N1 did not offer more protection than H5 alone.

The results, Lovell says, show the important role that H5 plays in developing immunity to bird flu.

In its viral form, H5 acts like a key allowing the virus to enter and attach itself to host cells where it then starts to replicate. Vaccines with small, safe doses of H5 prompt the body to recognize, remember and destroy the problematic intruder.

N1, meanwhile, acts as an enzyme in its viral form. Like a pair of scissors, it clips residues from the host cell, helping the replicated virus spread throughout the body.

“While they are non-neutralizing, N1 antibodies are still incredibly important. They reduce viral replication and the severity of illness,” Lovell says. “These bivalent formulations could be extremely advantageous as H5N1 evolves.”

Vaccine platform underwent COVID clinical trials

Lovell created the vaccine platform and has been experimenting with it for more than a decade. It consists of tiny spherical sacs called nanoparticles, which are made of cobalt and porphyrin with an outer shell of phospholipid – he calls it “CoPoP” for short.

(While not part of this study, the platform underwent phase 2 and phase 3 clinical trials in South Korea and the Philippines as a COVID-19 vaccine candidate. This work was a partnership between UB spinoff company POP Biotechnologies, co-founded by Lovell, and South Korean company EuBiologics.)

To create the experimental bird flu vaccine, the researchers added what’s called a histidine tag, or his-tag, to both the H5 and N1. His-tags are short strings of amino acids that have a natural affinity for metals. When mixed with CoPoP nanoparticles, the his-tag proteins form a strong bond with cobalt ions.

“It’s kind of like a magnet attaching itself to a metal surface. It just clicks into place. It’s fast and efficient, which is advantageous when you need to quickly ramp up vaccine production,” says Lovell.

To make the vaccine more potent, the researchers added two immune-boosting adjuvants – QS-21 and a synthetic monophosphoryl lipid A, or MPLA. The adjuvants are mixed into the phospholipid layer.

Easier to produce than egg-based vaccines

The vaccine is what’s known as a recombinant protein vaccine. Unlike currently approved vaccines, which use live or dead versions of H5N1, it relies on bits of genetic material (H5 and N1) from the virus to stimulate immune response.

“Because our vaccine does not require the use of eggs in the manufacturing process – as many influenza vaccines do – it is potentially a faster and more efficient way to protect humans and animals from deadly strains of bird flu,” Lovell says.

The research team plans additional work on the vaccine candidate, including testing different doses, schedules and conditions.

Study co-authors work at the Jacobs School of Medicine and Biomedical Sciences at UB; National Microbiology Laboratory, which is part of the Public Health Agency of Canada; St. Jude Children’s Research Hospital; POP Biotechnologies; National Center for Foreign Animal Disease, which is part of the Canadian Food Inspection Agency; and the University of Manitoba.

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Journal

Cell Biomaterials

Article Publication Date

17-Apr-2025