These teleconnections between the tropical Pacific and far-flung areas are reported in a Cornell University-led computer-model study published in Nature Geoscience.

While other computer models have projected similar precipitation increases generated by a warming Southern Ocean, major uncertainties and a wide range of predictions exist between models.

The new study serves to reduce those uncertainties, which could improve predictions of global mean temperatures and regional precipitation.

“We needed to find the cause of those uncertainties,” said Hanjun Kim, the study’s co-corresponding author and a postdoctoral associate working with co-authors Flavio Lehner and Angeline Pendergrass, both assistant professors of atmospheric sciences at Cornell. Sarah Kang, professor in the Max Planck Institute for Meteorology in Hamburg, Germany, is the paper’s other corresponding author.

“I found that low-altitude cloud feedbacks over the Southern Hemisphere can be one cause of those uncertainties in remote Northern Hemisphere regional precipitation,” Kim said. “If we try to reduce the uncertainty of Southern Hemisphere cloud feedbacks, then we can also improve the prediction of global mean temperatures.”

The Southern Ocean has a higher capacity for absorbing heat than other bodies of water due to a strong upwelling of deep cold water, but eventually the water will warm and gradually release heat. When this happens, that heat is distributed, creating teleconnections, which are predicted to increase precipitation in East Asia during summers and in the Western U.S. during winters. Such teleconnections are very similar to how El Niño affects weather patterns.

The model predicted that due to the ocean’s slow release of heat, the new precipitation patterns could persist for up to 150 years, regardless of efforts to reduce greenhouse gases.

“We can occasionally see these processes today, which allows us to study them,” Lehner said, “but we expect in the future for these processes to switch from being an occasional occurrence to being a more permanent state of the system.”

Kim found that low-lying clouds over the Southern Ocean act as a key regulator affecting sea-surface temperatures. Accounting for these cloud feedbacks in climate models help explain the uncertainties and variations from one model to another, according to the study.

There are few observational facilities in Antarctica to provide data on cloud feedbacks in the Southern Ocean, so increasing those would in turn improve predictions, Kim said.

HIV-diagnostic technology traditionally relied on the detection of HIV-specific antibodies that form several weeks after infection. This has limited their use in early detection, complicating patient care and HIV prevention efforts. Newer tests that detect both HIV antibodies and the p24 antigen (an earlier marker of HIV infection) are now the gold standard for diagnosis, but require clinical labs to run results, contributing to longer processing times, higher costs and the need for multiple patient visits.

The technology described in a study published today (April 2) in the journal Biosensors and Bioelectronics uses a nanomechanical platform and tiny cantilevers to detect multiple HIV antigens at high sensitivity in a matter of minutes. These silicon cantilevers are cheap and easy to mass produce and can be readily equipped with a digital readout. Built into a solar-powered device, this technology could be taken to hard-to-reach parts of the world where early detection remains a challenge to deliver fast interventions to vulnerable populations without waiting for a lab.

“We hope this technology will lead to the development of new point-of-care diagnostics for HIV to improve patient health and help bring an end to this epidemic,” said Northwestern virologist and co-author of the study, Judd F. Hultquist.

After proving its efficacy in testing for both the SARS-CoV-2 virus that causes COVID-19, and now HIV, the team is confident that the biosensor will continue to prove effective when testing for additional diseases. A potential next target, they say, could be measles, another infection in desperate need of point-of-care interventions as cases rise across multiple U.S. states.

The team was led by co-corresponding authors Vinayak Dravid, a materials engineer, Hultquist, a virologist, and co-author Gajendra Shekhawat, a micro- and nanofabrication expert in the Dravid Lab.

“When we first developed the microcantilever technology 20 years ago, I realized that this technology is so generally applicable,” Dravid said. “It is a very powerful tool that depends on three basic things: sensitivity, antigen-antibody affinity and specificity. This is where HIV comes in, because HIV is so pernicious that it mutates so there is no unique antibody. We had to figure out how to overcome that challenge.”

Beginning with pure samples of the p24 antigen, the team applied layers of antibodies onto each “finger” of the gold-coated microcantilever to measure how strongly p24 bonded to the surface, which would cause the cantilever to bend a measurable and quantifiable amount.

After this proof-of-concept, the team introduced human blood samples, which are much more complex than purified samples. The sensor continued to bend only in samples where p24 was present, demonstrating high specificity.

Finally, the scientists added two antibodies to different “fingers” of the microcantilever to more broadly cover all HIV subtypes. Even in very low concentrations, the test accurately responded when antigens specific to HIV were introduced.

“To account for HIV’s genetic diversity, we functionalized the test for HIV using broadly cross-reactive antibodies (ANT-152 and C65690M),” Shekhawat said. “This allowed accurate detection across diverse HIV-1 subtypes, ensuring reliability in global settings.”

To streamline diagnostics and enable immediate medical care, the team envisions developing a point-of-care test simultaneously detecting HIV, hepatitis B and hepatitis C antigens, acknowledging the higher prevalence of hepatitis co-infections in people living with HIV that can lead to severe liver complications if left untreated.

Dravid is the Abraham Harris Professor of Materials Science and Engineering at the McCormick School of Engineering and a faculty affiliate of the Paula M. Trienens Institute for Sustainability and Energy. He is also the founding director of the Northwestern University Atomic and Nanoscale Characterization (NUANCE) Center as well as the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource, and also serves as the associate director for global programs at the International Institute of Nanotechnology.

Hultquist is an assistant professor of medicine at Northwestern University Feinberg School of Medicine and serves as the associate director for the Center for Pathogen Genomics and Microbial Evolution in the Havey Institute for Global Health. He specializes in translational research of infectious diseases and host-pathogen interactions.

Shekhawat is a research professor of materials science and engineering at McCormick, researching semiconductor microfabrication, integration of sensors with synthetic biology and biomaterials and nanoscale characterization.

The research was supported by an award from the National Institutes of Health-funded Third Coast Center for AIDS Research (P30AI117943), as well as through NIH funding for the HIV Accessory & Regulatory Complexes Center (U54 AI170792) and NIH funding for HIV research (R01AI176599, R01AI167778, R01AI150455, R01AI165236, R01AI150998, R21 AI174864, and R56AI174877).

Vinayak Dravid, Gajendra Shekhawat, Judd Hultquist and Northwestern have financial interests (equities, royalties) in the reported research.

A dissection in the artery wall is most often caused by trauma due to motor vehicle accidents but can also occur with smaller injuries. Heavy lifting has also been shown to cause dissection in some people.

“Cervical artery dissection is an important cause of stroke, especially in people under 50, so it is crucial to detect it right away,” said Shadi Yaghi, MD, of Brown University in Providence, Rhode Island. “Strokes that are not fatal can lead to long-term disability, poor mental health and reduced quality of life. Our research found a dramatic increase in the number of hospitalizations for cervical artery dissection with rates rising steadily year over year.”

For the study, researchers reviewed 15 years of U.S. health data to identify 125,102 people hospitalized for cervical artery dissection. Participants had an average age of 51, and just over half had a stroke at the same time as dissection. Of all participants, 65% were white, 10% were Black, 8% were Hispanic, 3% were Asian or Pacific Islander, and 14% were of other racial groups.

Researchers compared the number of hospitalizations to U.S. Census data to determine the annual rate of cervical artery dissections. They then calculated the average annual percentage change in those rates.

Researchers found the number of dissections increased from 11 cases per one million people in 2005 to 46 cases per one million people in 2019, with an average annual increase of 10%. Results were similar for both female and male participants.

The average annual increase for Hispanic participants was 16%, for Black participants it was 13%, Asian participants, 12% and white participants, 8%.

Researchers also found a greater average annual increase among people 65 and older at 12% compared to 8% for people under 65.

“Possible reasons for this nearly five-fold increase over 15 years include greater awareness of cervical artery dissection by health care professionals, better access to imaging to help identify it and an overall increase in this condition for which a cause has yet to be determined,” said Yaghi. “Given the rising incidence of cervical artery dissection, our study underscores the importance of finding prevention strategies as well as new treatments to reduce the risk of stroke.”

A limitation of the study was that the hospital admission data does not include undiagnosed or untreated cases, so the number of cases may be even higher.

The study, published in the May issue of the journal Environmental Pollution, examined contamination levels for Mercury, Zinc, Cadmium and Antimony from nearly 50 sites in the Rocky Mountains. DRI’s Monica Arienzo, Associate Research Professor of Hydrology, led the research, along with colleagues from the U.S. Geological Survey (USGS), the University of Nevada, Reno, and Portland State University. They found higher levels of metal contaminants in the northern Rockies and identified mines in the Pacific Northwest, Idaho, and Montana as the likely source by following winter storms back in time. It is one of the first studies to look at metal contamination across the greater Rocky Mountains.

“Metal pollution in the Rockies is relatively understudied,” Arienzo said. “Other studies have focused on certain parts, so the fact that we have this transect from Montana to New Mexico makes this study unique.”

Although contamination levels were found to be within guidelines set by the EPA for both drinking water and aquatic life, dust can accelerate snowmelt by decreasing the reflectivity of the snowpack. The data can also provide critical information about how environmental contaminants and dust are distributed by the atmosphere.

The study combined a number of data sets to capture a comprehensive understanding of the amount of metal contamination making its way to the region. First, snow samples were collected from 48 sites throughout the Rocky Mountains during the spring of 2018. The researchers then measured metal concentrations in each sample, including metals like calcium that come from natural dust rather than human activities. By comparing the amounts of purely dust-sourced metals to those that result from both dust and industrial activities like mining, the scientists determined how much metal contamination stemmed from human activities.

To strengthen their findings, they then examined data from the National Atmospheric Deposition Program that measured mercury and calcium in precipitation from 2009 through 2018. Again, the scientists saw higher amounts of metal contamination in the northern Rockies, across Montana, Idaho, and Northern Wyoming.

“I was surprised by the amount of agreement we saw between all these different data sets we brought together,” Arienzo said. “The snow samples showed us that contamination is higher in the northern Rockies, and that was really interesting. Looking at mercury contamination over time helped us say that 2018 is not just a fluke. When you start to see these trends that are consistent between different records, it makes you feel more confident that something’s really happening here.”

To determine the likely source of the contaminants, Arienzo and her colleagues tracked the winter’s storms back through time. For the northern Rockies, many of the storms had moved in from the Pacific Northwest region, whereas in the southern stretch of the mountains, storms came from across the Mojave Desert.

By referencing a USGS dataset that tracks mining and smelting locations, the scientists identified active sites near the northern Rockies. An examination of EPA Superfund locations uncovered historical sites that could also be sources of contamination.

“Our idea is that the dust from current and historical mining sites gets carried up into the mountains and deposited across our study sites,” Arienzo said. “This study shows the importance of continued scientific monitoring efforts, like the long-term USGS datasets we used here, as well as mitigation of current and historical mining sites.”

The research is part of a larger study, supported by the National Science Foundation (NSF), using tree rings to examine historical mercury contamination. Arienzo and her team will compare the mercury record found in tree rings to that found in the snowpack to better understand how mercury is deposited and spread throughout the environment.

Now, findings from researchers at Texas A&M University provide new, evidence-based insight into minimizing the risk of these diseases at canine facilities.

“In adult, healthy humans and animals, these diseases usually cause diarrhea and occasionally other minor ailments, but for infants, puppies and the immunocompromised, infection could be deadly,” said Loni Taylor, PhD, DVM, an epidemiologist with the Texas A&M University School of Public Health, who led the study. “We wanted to identify the factors associated with kennel-housed dogs in Texas that test positive for both diseases.”

For their study, published in Comparative Medicine, Taylor and five colleagues with Texas A&M’s College of Veterinary Medicine & Biomedical Sciences sought to find out if a dog’s score on the Purina Fecal Scoring chart, breed, sex or age was associated with testing positive on a fecal screening test for either Giardia, Cryptosporidium or both organisms together.

To accomplish this, they tested fecal samples collected from a census sample of 153 clinically normal dogs housed at Texas kennels between March and October 2021. Breeds included golden retrievers, Labrador retrievers, beagles and a variety of large hounds and hound mixes.

The sex, age, breed and location were noted for the 153 dogs studied. In addition, fecal scores were determined by a single researcher using visual assessment of the samples, based on the Purina Institute metric (where 1 is hard and 7 is watery).

A secondary data analysis and statistical analysis found that dogs were significantly more likely to test positive for Giardia (45%) than Cryptosporidium (7%) (P < 0.01), although no clear link was found between sex or breed and these infections.

In addition, kennel-housed dogs 18 months of age or younger had 3.4 times the odds of Giardia infection compared with older dogs, and hard stool was associated with negative test status for Giardia in the stool.

No statistically significant relationship was found for age or fecal score and Cryptosporidium-positive test status, and Taylor noted that additional studies with larger sample sizes could help identify such a relationship.

“The primary takeaway is that age and fecal score are important factors for choosing which dogs to screen for subclinical Giardia,” Taylor said. “And given the increased odds of Giardia infection, screening should be as robust as the recommended combination of testing methods.”

Now, researchers in the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) are doubling down, literally, on metasurface technology by creating a bilayer metasurface, made of not one, but two stacked layers of titanium dioxide nanostructures. Under a microscope, the new device looks like a dense array of stepped skyscrapers.

The research is published in Nature Communications.

“This is a feat of nanotechnology at the highest level,” said senior author Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS. “It opens up a new way to structure light, in which we can engineer all its aspects such as wavelength, phase and polarization in an unprecedented manner…It signifies a new avenue for metasurfaces that so far has been just scratching the surface.”

For centuries, optical systems have relied on bulky, curved lenses made of glass or plastic to bend and focus light. The SEAS-led metasurface revolution of the last decade has produced flat, ultra-thin structures patterned with millions of tiny elements that can manipulate light with nanometer precision. A striking example technology is the metalens: Unlike conventional lenses, metalenses can be fabricated with existing semiconductor manufacturing, making possible compact, integrated optical systems in devices like smartphones, cameras, and augmented reality displays.

After Capasso’s team reported their first working metalens that can bend visible light, they worked with Harvard’s Office of Technology Development to license the technology and start a company, Metalenz. They’ve since demonstrated a host of potential applications, including an endoscope, an artificial eye, and a telescope lens.

But the single-layer nanostructure design Capasso’s team invented has been in some ways limiting. For example, previous metasurfaces put specific requirements on the manipulation of light’s polarization — that is, the orientation of the light waves — in order to control the light’s behavior.

“Many people had investigated the theoretical possibility of a bilayer metasurface, but the real bottleneck was the fabrication,” said Alfonso Palmieri, graduate student and co-lead author of the study. With this breakthrough, Palmieri explained, one could imagine new kinds of multifunctional optical devices — for example, a system that projects one image from one side and a completely different image from the other.

Using the facilities of the Center for Nanoscale Systems at Harvard, the team that included former postdoctoral researchers Ahmed Dorrah and Joon-Suh Park came up with a fabrication process for freestanding, sturdy structures of two metasurfaces that hold strongly together but do not affect each other chemically. While such multi-level patterning has been common in the silicon semiconductor world, it had not been as well explored in optics and metaoptics.

To demonstrate the power of their device, the team devised an experiment in which they used their bilayer metalens to act on polarized light in the same way that a complicated system of waveplates and mirrors does.

In future experiments, the team could expand into even more layers to exert control over other aspects of light, such as extreme broadband operation with high efficiency across the entire visible and near infrared spectrum, opening the door to even more sophisticated light-based functionalities.

The research was supported by several federal funding sources, including the Office of Naval Research under grant No. N00014-20-1-2450, and from the Air Force Office of Scientific Research under grant No.s FA9550-21-1-0312 and FA9550-22-1-0243. The devices were made at the Harvard University Center for Nanoscale Systems, part of the National Nanotechnology Coordinated Infrastructure Network, which is supported by the National Science Foundation under NSF award No. ECCS-2025158.

Staff acknowledgments: Stephan Kraemer supported the focused ion beam process, and Mac Hathaway supported the atomic layer deposition process.