Life zones are distinct biogeographic regions characterized by biotemperature, precipitation, and aridity representing broad-scale ecosystem types.

The study revealed that the world’s life zones have already changed from the early 1900s until present day across all biomes, most notably in Boreal Forests, Temperate Coniferous Forests, and Tropical Coniferous Forests. This includes impacts to 27 million square kilometers (10.4 million square miles) or 18.3 percent of earth’s land. Boundaries between life zones have shifted poleward and towards higher elevations, leading to expansions of zones associated with equatorial climates and contractions of zones associated with temperate climates.

Anticipated future changes are expected to accelerate rapidly, particularly if the world does not act on reducing emissions. This includes potential impacts to an additional potential of 62 million square kilometers (24 million square miles) or 42.6 percent of earth’s land under ‘business-as-usual’.

Life zones associated with subpolar rain tundra, wet tundra, and moist tundra are projected to experience the largest decreases while tropical wet forest, tropical rain forest, and cool temperate moist forest are projected to experience the largest increases. Boreal and polar latitudes are projected to experience substantial losses of area, although their vast extent will help compensate for some of these expected losses.

Said Dr. Paul Elsen, WCS Climate Adaptation Scientist and lead author of the study: “The likely future changes in the world’s life zones is likely to have a substantial impact on people livelihoods and biodiversity. Large areas of the world are getting hotter and drier and this is already impacting the earth’s life zones.”

Dr. Hedley Grantham, WCS Director of Conservation Planning and coauthor of the study said: “COP26 is our best chance of countries committing to reducing emissions and putting us on a better future pathway for climate change and its impacts.”

The study is published in Global Change Biology.

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A research letter detailing the study of nearly 2,000 health care workers appears today in the Journal of the American Medical Association.

“This finding adds to our understanding of how immunity against SARS-CoV-2 works, and builds upon an earlier study by our team that showed the mRNA vaccines yielded a robust antibody response, even if a person did not develop significant symptoms following vaccination or did not have a prior SARS-CoV-2 infection,” says study senior author Aaron Milstone, M.D., M.H.S., professor of pediatrics at the Johns Hopkins University School of Medicine and pediatric epidemiologist at Johns Hopkins Children’s Center.

The two mRNA vaccines evaluated in the study introduce the body’s immune system to S1, a protein subunit that’s a component of the spikes found on the surface of SARS-CoV-2. The spikes enable the virus to latch onto healthy cells and infect them. Immunoglobulin G antibodies, elicited by S1 from the vaccines stimulating the immune system, neutralize the virus particles, preventing infection by SARS-CoV-2, or at least, reducing the severity of the disease.

For their latest study, the researchers followed 1,960 Johns Hopkins Medicine health care workers who had received both doses of either the Pfizer/BioNTech or Moderna vaccines, including 73 people who had a positive SARS-CoV-2 polymerase chain reaction (PCR) test result before the first vaccine dose. The 73 were divided into two groups — those who were infected at 90 days or closer to the first vaccine dose, and those whose exposure to the virus was more than 90 days before the initial shot.

After adjusting for vaccine type, age and sex, antibody levels were compared for those with and without prior SARS-CoV-2 infection at one, three and six months following the second vaccine dose. In addition, antibody levels were compared at one and three months following the second dose between the two groups with prior SARS-CoV-2 infection.

“We found that health care workers with prior SARS-CoV-2 infection followed by two doses of mRNA vaccine — therefore, three independent exposures to the S1 spike protein — developed higher antibody levels than those with vaccination alone,” says study lead author Diana Zhong, M.D., an infectious diseases fellow at the Johns Hopkins University School of Medicine. “The relative differences were 14% higher at 1 month following the second vaccine dose, 19% at three months and 56% at six months.”

Zhong adds that the study participants with a PCR-confirmed SARS-CoV-2 infection more than 90 days before their initial vaccination had adjusted antibody levels 9% (one month following the second vaccine dose) and 13% (three months following the second vaccine dose) higher than those who were exposed to the virus less than or equal to the 90-day mark.

“This suggests that a longer interval between infection and first vaccine dose may enhance the antibody response,” says Milstone.

Milstone says further investigation is needed to determine whether increased post-vaccination durability in previously infected people is attributable to the number of exposures to the virus, the interval between exposures, or the interplay between natural or vaccine-derived immunity.

The study team at Johns Hopkins Medicine was co-led by Zhong and Shaoming Xiao. Along with them and Milstone, the team includes Amanda Debes, Emily Egbert, Patrizio Caturegli and Elizabeth Colantuoni.

This study was supported by National Institute of Allergy and Infectious Diseases/National Institutes of Health grants T32AI007291 and K24AI141580, along with contributions to the COVID-19 research funds of the Johns Hopkins University School of Medicine and the Johns Hopkins Health System.

Silicon’s 3D lattice, however, is too big for next-generation electronics, which include ultra-thin transistors, new devices for optical communication, and flexible bio-sensors that can be worn or implanted in the human body. To slim things down, researchers are experimenting with materials no thicker than a single sheet of atoms, such as graphene. But the tried-and-true method for doping 3D silicon doesn’t work with 2D graphene, which consists of a single layer of carbon atoms that doesn’t normally conduct a current.

Rather than injecting dopants, researchers have tried layering on a “charge-transfer layer” intended to add or pull away electrons from the graphene. However, previous methods used “dirty” materials in their charge-transfer layers; impurities in these would leave the graphene unevenly doped and impede its ability to conduct electricity.

Now, a new study in Nature Electronics proposes a better way. An interdisciplinary team of researchers, led by James Hone and James Teherani at Columbia University, and Won Jong Yoo at Sungkyungkwan University in Korea, describe a clean technique to dope graphene via a charge-transfer layer made of low-impurity tungsten oxyselenide (TOS).

The team generated the new “clean” layer by oxidizing a single atomic layer of another 2D material, tungsten selenide. When TOS was layered on top of graphene, they found that it left the graphene riddled with electricity-conducting holes. Those holes could be fine-tuned to better control the materials’ electricity-conducting properties by adding a few atomic layers of tungsten selenide in between the TOS and the graphene.

The researchers found that graphene’s electrical mobility, or how easily charges move through it, was higher with their new doping method than previous attempts. Adding tungsten selenide spacers further increased the mobility to the point where the effect of the TOS becomes negligible, leaving mobility to be determined by the intrinsic properties of graphene itself. This combination of high doping and high mobility gives graphene greater electrical conductivity than that of highly conductive metals like copper and gold.

As the doped graphene got better at conducting electricity, it also became more transparent, the researchers said. This is due to Pauli blocking, a phenomenon where charges manipulated by doping block the material from absorbing light. At the infrared wavelengths used in telecommunications, the graphene became more than 99 percent transparent. Achieving a high rate of transparency and conductivity is crucial to moving information through light-based photonic devices. If too much light is absorbed, information gets lost. The team found a much smaller loss for TOS-doped graphene than for other conductors, suggesting that this method could hold potential for next-generation ultra-efficient photonic devices.

“This is a new way to tailor the properties of graphene on demand,” Hone said. “We have just begun to explore the possibilities of this new technique.”

One promising direction is to alter graphene’s electronic and optical properties by changing the pattern of the TOS, and to imprint electrical circuits directly on the graphene itself. The team is also working to integrate the doped material into novel photonic devices, with potential applications in transparent electronics, telecommunications systems, and quantum computers.

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Materials provided by Columbia University. Original written by Ellen Neff. Note: Content may be edited for style and length.

Florian Dirnberger, post-doc in Vinod Menon’s research group in CCNY’s Center for Discovery and Innovation, and one of the lead authors of the study that appears in the journal Science Advances, detailed the team’s breakthrough. “Our main achievement was to manage to create these excitonic wires, essentially one-dimensional channels for excitons, in what is otherwise a two-dimensional semiconductor,” he said. “Since charge neutral excitons are not simply controlled by external voltages, we had to rely on a different approach. By depositing the atomically thin 2D crystal on top of a microscopically small wire, a thousand times thinner than a human hair, we created a small, elongated dent in the two-dimensional material, slightly pulling apart the atoms in the two-dimensional crystal and inducing strain in the material. For excitons, this dent is much like a pipe for water and once trapped inside, they are bound to move along the pipe, realizing quasi one-dimensional transport of excitons.”

This advancement holds possibilities for new devices.

“Manipulating the motion of excitons at the nanoscale realizes an important step towards excitonic devices,” noted Dirnberger. “Platforms based on two-dimensional semiconductor transition-metal dichalcogenides offer an interesting new approach called straintronics.”

Possible outcomes include innovative devices based on excitons that operate at room temperature and could replace certain tasks performed by contemporary transistor technology.

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Arunima Krishna, a Boston University College of Communication researcher who studies public perceptions of controversial social issues, is studying the spread of disinformation, specifically related to climate science — an issue that has been manipulated by climate change deniers for decades. In her latest study, Krishna surveyed 645 Americans about their beliefs on climate change — whether or not those beliefs are informed by fact or fiction — to assess their communication behaviors about climate change.

“I think a lot of folks don’t see how close to home climate change is. Even though we’re seeing climate refugees, [worsening] hurricanes, and other [natural] disasters, there is still a level of distance from the problem,” says Krishna, a College of Communication assistant professor of public relations.

She points out that physical distance from the effects of climate change could be partly why some people find it is easier to separate themselves from the climate crisis. Plus, climate solutions are often things many people don’t readily want to do, like eating less meat, using less plastic, and buying less material goods. Fossil fuel companies and lobbyists for the industry have also worked extremely hard to deceive the public from knowing the full extent of the damaging impact of burning fossil fuels, she says.

According to Krishna’s survey of Americans, 7 in 10 people who are susceptible to believing climate disinformation self-identified as politically conservative. In contrast, 8 in 10 Americans who self-identified as liberal were found to be immune to disinformation about climate change. Those findings double down on past research from the Yale Program on Climate Change Communication, which found liberals and Democrats are significantly more worried about climate change than conservatives and Republicans, and are more likely to believe humans are causing the climate crisis.

Krishna also detected a difference in age between those who were more susceptible to disinformation and those who weren’t. More than half of the respondents immune to false information about climate were under 45. Those more receptive to climate disinformation were, on average, over the age of 46.

Diving deeper into the respondents’ responses, Krishna categorized the survey results into four different groups. The first segment, made up of people she calls the “disinformation immune,” have not accepted any disinformation about climate change and humans’ role in it, and they likely never will. The second group, the”disinformation vulnerable,” have negative attitudes about how humans are influencing climate. While they haven’t yet accepted disinformation, some of their responses to facts about climate change — as well as their attitudes and motivations — indicate they could possibly believe climate disinformation in the future. The third group, the “disinformation receptive,” have accepted false information about climate change already. Lastly, the fourth group, the “disinformation amplifying,” is made up of people who hold extremely negative attitudes about climate change and doubt humans’ role in accelerating it, have already accepted disinformation, and are highly motivated to spread the disinformation they believe.

“My study found that [disinformation amplifiers] are more likely to spread their opinions about climate change compared to everybody else in the survey,” Krishna says. The amplifiers are known as what Krishna calls “lacuna publics,” a term she coined in 2017 when she was researching vaccine hesitant groups. (The word “publics” refers to groups connected by issue-specific motivation, and “lacuna” means a gap in knowledge.) Though the disinformation amplifiers, or lacuna publics, are in the minority, they are different from groups that are disinformation vulnerable or receptive because of their willingness to spread disinformation.

The United States has more climate skeptics than anywhere else in the world, Krishna says, but their ranks have started to shrink. Climate scientists around the world have found unequivocally that the more we continue to emit heat-trapping greenhouse gases into the atmosphere, the worse the consequences will be for humans, most species, and ecosystems on Earth.

Though there is no single solution to stopping the spread of climate disinformation, Krishna emphasizes the importance of engaging with people most vulnerable to believing disinformation. Lacuna publics, or amplifiers, however, might be difficult or impossible to sway.

“It might not be worth using resources to try to reach the lacuna publics,” Krishna says. “Research tells us that one-on-one interaction can often be more effective than mass media messages…so perhaps that’s the best way to [elevate] voices who are disinformation immune.”

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Materials provided by Boston University. Original written by Jessica Colarossi. Note: Content may be edited for style and length.