In the 1950s in the Northern Hemisphere, the four seasons arrived in a predictable and fairly even pattern. But climate change is now driving dramatic and irregular changes to the length and start dates of the seasons, which may become more extreme in the future under a business-as-usual climate scenario.

“Summers are getting longer and hotter while winters shorter and warmer due to global warming,” said Yuping Guan, a physical oceanographer at the State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, and lead author of the new study in Geophysical Research Letters, AGU’s journal for high-impact, short-format reports with immediate implications spanning all Earth and space sciences.

Guan was inspired to investigate changes to the seasonal cycle while mentoring an undergraduate student, co-author Jiamin Wang. “More often, I read some unseasonable weather reports, for example, false spring, or May snow, and the like,” Guan said.

The researchers used historical daily climate data from 1952 to 2011 to measure changes in the four seasons’ length and onset in the Northern Hemisphere. They defined the start of summer as the onset of temperatures in the hottest 25% during that time period, while winter began with temperatures in the coldest 25%. Next, the team used established climate change models to predict how seasons will shift in the future.

The new study found that, on average, summer grew from 78 to 95 days between 1952 to 2011, while winter shrank from 76 to 73 days. Spring and autumn also contracted from 124 to 115 days, and 87 to 82 days, respectively. Accordingly, spring and summer began earlier, while autumn and winter started later. The Mediterranean region and the Tibetan Plateau experienced the greatest changes to their seasonal cycles.

If these trends continue without any effort to mitigate climate change, the researchers predict that by 2100, winter will last less than two months, and the transitional spring and autumn seasons will shrink further as well.

“Numerous studies have already shown that the changing seasons cause significant environmental and health risks,” Guan said. For example, birds are shifting their migration patterns and plants are emerging and flowering at different times. These phenological changes can create mismatches between animals and their food sources, disrupting ecological communities.

Seasonal changes can also wreak havoc on agriculture, especially when false springs or late snowstorms damage budding plants. And with longer growing seasons, humans will breathe in more allergy-causing pollen, and disease-carrying mosquitoes can expand their range northward.

Going to extremes

This shift in the seasons may result in more severe weather events, said Congwen Zhu, a monsoon researcher at the State Key Laboratory of Severe Weather and Institute of Climate System, Chinese Academy of Meteorological Sciences, Beijing, who was not involved in the new study.

“A hotter and longer summer will suffer more frequent and intensified high-temperature events — heatwaves and wildfires,” Zhu said. Additionally, warmer, shorter winters may cause instability that leads to cold surges and winter storms, much like the recent snowstorms in Texas and Israel, he said.

“This is a good overarching starting point for understanding the implications of seasonal change,” said Scott Sheridan, a climate scientist at Kent State University who was not part of the new study.

It is difficult to conceptualize a 2- or 5-degree average temperature increase, he said, but “I think realizing that these changes will force potentially dramatic shifts in seasons probably has a much greater impact on how you perceive what climate change is doing.”

Scientists at the University of Washington and the University of Central Florida inoculated 126 species of plants in the sunflower family with powdery mildew, growing 500 plants from seeds that were collected from the wild and provided from the USDA germplasm network. Through this large-scale study, they were able to measure the various plants’ susceptibility to powdery mildew.

“We observed that the amount of disease present on a host can be dependent on where that host lies on the tree of life — that is, the evolutionary history of a host can predict how susceptible that host is to disease,” explained Michael Bradshaw, a plant pathologist involved with the study.

They also measured common plant traits, such as biomass, trichome density, and chlorophyll content, and found that none of them were associated with the disease, underscoring the unimportance of commonly assessed host plant traits in powdery mildew severity and pointing further to the role that evolutionary history plays in plant susceptibility to disease.

“Any tools we can use to predict the severity of a disease can be valuable and improve management guidelines. Especially with fungal pathogens, where there is often a large lag time between the introduction of a pathogen and the formation of an epidemic,” Bradshaw said. “I am hopeful that this research could spur future work and provide ideas and techniques for other researchers studying the evolution of disease.”

This research provides information on species of sunflower plants that are resistant to powdery mildew disease, which can be beneficial to breeding programs. Bradshaw also hopes that this study will inspire other studies that mine the genome of different plant species involved to potentially locate genes involved with resistance.

Story Source:

Materials provided by American Phytopathological Society. Note: Content may be edited for style and length.

A meta-analysis in The Lancet Global Health, consisting of 48,000 people from 17 studies, found that those with more severe vision impairment had a higher risk of all-cause mortality compared to those that had normal vision or mild vision impairment.

According to the data, the risk of mortality was 29% higher for participants with mild vision impairment, compared to normal vision. The risk increases to 89% among those with severe vision impairment.

Importantly, four of five cases of vision impairment can be prevented or corrected. Globally, the leading causes of vision loss and blindness are both avoidable: cataract and the unmet need for glasses.

The study’s lead author, Joshua Ehrlich, M.D., M.P.H., sought to better understand the association between visual disabilities and all-cause mortality.

The work complements some of Ehrlich’s recent research, also in The Lancet Global Health Commission on Global Eye Health, that highlighted the impact of late-life vision impairment on health and well-being, including its influence on dementia, depression, and loss of independence.

“It’s important these issues are addressed early on because losing your vision affects more than just how you see the world; it affects your experience of the world and your life,” says Ehrlich. “This analysis provides an important opportunity to promote not only health and wellbeing, but also longevity by correcting, rehabilitating, and preventing avoidable vision loss across the globe.”

Story Source:

Materials provided by Michigan Medicine – University of Michigan. Original written by Jordyn Imhoff. Note: Content may be edited for style and length.

A long-running summer program at Rice University and elsewhere that trains high school girls in basic physics concepts has proven successful in helping them thrive when they take on full courses the next year.

When leaders of Rice’s two-week day camp looked at similar programs beyond Houston, they found participants scored 3% better in high school physics than their counterparts who did not have the equivalent summer experience.

“That doesn’t seem like a lot, but it’s really hard to move the needle on student outcomes, so 3% is significant,” said Carolyn Nichol, an assistant research professor in the Department of Chemistry and director of the Rice Office of STEM Engagement (R-STEM).

The results are detailed in an open-access study by Nichol, lead author Ericka Lawton, and co-authors Carrie Obenland and Matthew Cushing of R-STEM and Christopher Barr of the Rice Office of Research in the American Physics Society journal Physical Review Physics Education Research.

The study is one of two led and recently released by Nichol. The other analyzes the effect of long-term professional development for teachers in engineering education. That study by Nichol, lead author Christina Crawford of R-STEM and co-author Obenland appears in the Journal of STEM Outreach.

The high school study collected years’ worth of generalized data from participating districts for students who studied chemistry but did not participate in a camp, and the same data for those who did. That gave researchers a baseline to compare results for the same set of students after they all took high school physics.

“There wasn’t a self-selection bias where people could say, ‘Oh, girls who go to a physics camp in June already like physics,'” she said, noting Rice and its counterparts typically recruit students from underserved schools. “The girls who were part of the study were matched so their chemistry scores were the same. We didn’t base this on girls who were already accelerating in science.”

The study was based on a philanthropic effort by Rice alumna and trustee Wanda Gass ’78, an engineer who helped develop the first commercially viable digital signal processor during her career at Texas Instruments. She subsequently founded the nonprofit Design Connect Create to encourage girls to pursue STEM (science, technology, engineering, math) studies.

Design Connect Create runs summer camps for multiple school districts across Texas. Nichol said the study is great validation for the physics program that will ideally lead to similar courses in other science-oriented topics.

“When I talk to these girls at Rice, and often they really don’t want to be here,” she said. “They’re very quiet at the start because for the most part, they are being forced to come by their parents. But by the end, they form really wonderful bonds with the other girls. Within two weeks, they are sharing skills and become trusting of each other.

“I think that’s the real reason they go back and are successful in physics,” Nichol said. “They just get this confidence that they can do it.”

The second study sought to show the value of professional development for teachers whose coursework touches on engineering topics but who are not, themselves, engineers. The researchers followed up with teachers who took the 45-hour graduate level course at Rice in 2018 and 2019 to see how they incorporated engineering into their classrooms.

The study found that, based on a set of attributes for adult self-motivation, teachers showed significant improvement in overall self-efficacy — the belief in their own ability to succeed — in engineering instruction.

“I’m an engineer because my dad was an engineer,” said Nichol, who has a doctorate in chemical engineering. “We want engineering in K-12 classrooms because a lot of kids don’t have role models, and we want them to understand that an engineer is somebody who designs and creates new things.”

She said the program that best exemplifies what Rice offers is the NanoEnvironmental Engineering for Teachers course, which gives participants rigorous hands-on experience working on water sustainability projects. The course, a collaboration with the Rice-based and National Science Foundation-backed Nanotechnology Enabled Water Treatment Center, is also offered at Arizona State and the University of Texas at El Paso.

Lawton is associate director for educational leadership and STEM initiatives, Obenland is a lecturer and associate director for outreach and research, Crawford is associate director for science and engineering and Cushing is executive director of R-STEM. Barr is director of assessment and evaluation of STEM programs in the Office of Research.

High operations and maintenance costs and low population density in some rural areas result in prohibitively high service fees — even for a subscriber-owned cooperative structured to prioritize member needs over profits, the analysis found.

Decades ago, cooperatives were key to the expansion of electric and telephone service to underserved rural areas, spurred by New Deal legislation providing low-interest government grants and loans. Public funding for rural broadband access should similarly consider its critical role supporting economic development, health care and education, said Todd Schmit, associate professor in the Charles H. Dyson School of Applied Economics and Management.

“The New Deal of broadband has to incorporate more than building the systems,” Schmit said. “We have to think more comprehensively about the importance of getting equal access to these technologies.”

Schmit is the co-author with Roberta Severson, an extension associate in Dyson, of “Exploring the Feasibility of Rural Broadband Cooperatives in the United States: The New New Deal?” The research was published Feb. 13 in Telecommunications Policy.

More than 90% of Americans had broadband access in 2015, according to the study, but the total in rural areas was below 70%. Federal programs have sought to help close that gap, including a $20.4 billion Federal Communications Commission initiative announced last year to subsidize network construction in underserved areas.

Schmit and Severson studied the feasibility of establishing a rural broadband cooperative to improve access in Franklin County in northern New York state, which received funding for a feasibility study from the U.S. Department of Agriculture’s Rural Business Development Program.

The researchers partnered with Slic Network Solutions, a local internet service provider, to develop estimates of market prices, the cost to build a fiber-to-the-home network, operations and maintenance costs, and the potential subscriber base — about 1,600 residents — and model a cooperative that would break even over a 10-year cycle.

Federal and state grants and member investment would cover almost the entire estimated $8 million construction cost, so that wasn’t a significant factor in the analysis, the researchers said.

But even with those subsidies, the study determined the co-op would need to charge $231 per month for its high-speed service option — 131% above market rates. At that price, it’s unlikely 40% of year-round residents would opt for high-speed broadband as the model had assumed, casting further doubt on its feasibility.

The $231 fee included a surcharge to subsidize a lower-speed service option costing no more than $60 — a restriction the construction grants imposed to ensure affordability. Without that restriction, the high-speed price would drop to $175 and the low-speed climb to $105.

“In short,” the authors wrote, “grants covering investment and capital construction alone do not solve the rural broadband problem, at least in our study area.”

As an alternative — though not one available in Franklin County — Schmit and Severson examined the possibility of an existing rural electric or telecommunications co-op expanding into broadband. They would gain efficiencies from already operating infrastructure such as the poles that would carry fiber lines. In that scenario, the high-speed price improved to $144 a month — still 44% above market rates.

“These systems are very costly to operate and maintain,” Schmit said, “particularly in areas like we looked at that are very low density.”

The feasibility improves with growth in a coverage area’s density and “take rate,” or percentage of potential subscribers signing up at different speeds, according to the analysis. But in Franklin County, the researchers determined a startup co-op would need 14 potential subscribers per mile to break even over 10 years — more than twice the study area’s actual density.

To better serve such areas, Schmit and Severson said, policymakers should explore eliminating property taxes on broadband infrastructure and payments to rent space on poles owned by regulated utilities, which respectively accounted for 16% and 18% of the proposed co-op’s annual expenses. Those measures reduced an expanding rural utility co-op’s high-speed fee to 25% above market rates, a level members might be willing to pay, the authors said.

“Consideration of the public benefits of broadband access arguably needs to be added to the equation,” they wrote. “The case was made for electricity and telephone services in the 1930s and similar arguments would seem to hold for this technology today.”

But the seven-second video, which is sped-up from 19 minutes, is real.

The hand, which would take six hours to create using conventional 3D printing methods, demonstrates what University at Buffalo engineers say is progress toward 3D-printed human tissue and organs — biotechnology that could eventually save countless lives lost due to the shortage of donor organs.

“The technology we’ve developed is 10-50 times faster than the industry standard, and it works with large sample sizes that have been very difficult to achieve previously,” says the study’s co-lead author Ruogang Zhao, PhD, associate professor of biomedical engineering.

The work is described in a study published Feb. 15 in the journal Advanced Healthcare Materials.

It centers on a 3D printing method called stereolithography and jelly-like materials known as hydrogels, which are used to create, among things, diapers, contact lenses and scaffolds in tissue engineering.

The latter application is particularly useful in 3D printing, and it’s something the research team spent a major part of its effort optimizing to achieve its incredibly fast and accurate 3D printing technique.

“Our method allows for the rapid printing of centimeter-sized hydrogel models. It signifcantly reduces part deformation and cellular injuries caused by the prolonged exposure to the environmental stresses you commonly see in conventional 3D printing methods,” says the study’s other co-lead author, Chi Zhou, PhD, associate professor of industrial and systems engineering.

Researchers say the method is particularly suitable for printing cells with embedded blood vessel networks, a nascent technology expected to be a central part of the production of 3D-printed human tissue and organs.

Story Source:

Materials provided by University at Buffalo. Original written by Cory Nealon. Note: Content may be edited for style and length.

So-called gene drives, which leverage CRISPR technology to influence genetic inheritance, carry the promise of rapidly spreading specific genetic traits throughout populations of a given species. Gene-drive technologies applied in insects, for example, are being designed to halt the spread of devastating diseases such as malaria and dengue by preventing mosquito hosts from becoming infected. In agricultural fields, gene-drives are being developed to help control or eliminate economically damaging crop pests.

But along with the capacity to alter populations, concerns have been raised regarding the long-term effects of these transformative new technologies in the wild. Researchers and ethicists have voiced questions about how gene drives, once turned loose in a regional population, could be held in check if necessary.

Now, researchers at the University of California San Diego, Tata Institute for Genetics and Society (TIGS) at UC San Diego and their colleagues at UC Berkeley have developed a new method that provides more control over gene drive releases. Details of the new “split drive” are published March 5 in the journals Nature Communications and eLife.

The most common gene drives employ a two-component system that features a DNA-cutting enzyme (called Cas9) and a guide RNA (or gRNA) that targets cuts at specific sites in the genome. Following the Cas9/gRNA cut, the gene drive, along with the cargo it carries, is copied into the break site through a DNA repair process.

While classic gene drives are designed to spread autonomously, the newly developed system is designed with controls that separate the genetic implementation processes. The split-drive system consists of a non-spreadable Cas9 component inserted into one location in the genome and a second genetic element that can copy itself — along with a beneficial trait — at a separate site. When both elements are present together in an individual, an “active gene drive” is created that spreads the element carrying the beneficial trait to most of its progeny. Yet, when uncoupled, the element carrying the beneficial trait is inherited under typical generational genetics rules, or Mendelian frequencies, rather than spreading unrestrained.

As described in the Nature Communications paper, by creating slight fitness costs that eventually eliminate the Cas9 enzyme from the population, the split-drive system vastly increases control and safety of the genetic deployments.

“Studying drives in essential genes is not a novel idea, per se, but we observed that certain split situations were able to spread a cargo effectively upon a first introduction while leaving no trace of Cas9 after a few generations, as well as few mistakes in the DNA repair process that got rapidly diluted out,” said Gerard Terradas, first author in the Nature Communications paper and a postdoctoral scholar in the UC San Diego Division of Biological Sciences.

The Nature Communications paper also spells out advantages on how gene drives are perceived by the public, as efforts to alter wild populations could be flexibly designed in a variety of ways per the desired outcome.

The new split-drive system follows research announced in September in which UC San Diego researchers led the development of two new active genetics neutralizing strategies that are designed to halt or inactivate gene drives released in the wild.

“We hope that the flexible design features we have developed will be broadly applicable by enabling tailored approaches to controlling insect vectors and pests in diverse contexts,” said UC San Diego Distinguished Professor Ethan Bier, senior author of the Nature Communications study and science director for TIGS-UC San Diego.

“These seminal papers reflect a tremendous effort, and fruitful cross-UC collaborations, to demonstrate novel gene drive architectures for mitigating the formation of resistant alleles while providing a safe confinable means for modification of wild populations,” said UC San Diego Associate Professor Omar Akbari, senior author of the eLife study.

Story Source:

Materials provided by University of California – San Diego. Original written by Mario Aguilera. Note: Content may be edited for style and length.