Culture
During the mating season, male damselflies battle fiercely for control of prime territories containing resources - typically patches of floating leaves used for egg deposition in wetlands - that are key to attracting females. To the victors go the spoils: though a dominant male must then diligently guard his hard-won territory against interlopers, ownership of a territory gives him exclusive access to the females that congregate within his domain.
Some of his rivals, however, refuse to play by the rules.
While the era of app-based ridehailing services, such as Uber and Lyft, has been credited with keeping more impaired drivers off the road, increasing job opportunities and offering new levels of convenience, it is also linked with more congestion and traffic deaths.
The arrival of ridehailing is associated with an increase of approximately 3 percent in the number of motor vehicle fatalities and fatal accidents, according to research from the University of Chicago Booth School of Business.
Human genetic testing has evolved over the recent decades, allowing people to find their ancestors and even determine specific percentages of their heritage. Much like the advances in human genetic testing recently popularized by commercial organizations have allowed people to gain a better understanding of their ancestry, scientists are now a step closer to determining a genetic family tree for vegetables by linking biology with computer science.
Hip fractures in older adults can be extremely serious, and often result in chronic illness, death, and increased health care costs. Experts estimate that some 18 to 33 percent of all older adults who have suffered hip fractures will die within a year, with even higher rates of death among people who have dementia or who live in a nursing home.
For the last quarter century, researchers have been asking whether genetic information might have negative psychosocial effects. Anxiety, depression, disrupted relationships, and heightened stigmatization have all been posited as possible outcomes--but not consistently found. What accounts for the discrepancy?
The towering, hundred-year-old Sitka spruce trees growing in the heart of Vancouver Island's Carmanah Valley appear placid and unchanging.
In reality, each one is packed to the rafters with evolutionary potential.
DURHAM, N.C. -- Numerous studies show that the legacy of hardship can be passed from one generation to the next. The good news is that resilience can cross generations too.
Bottom Line: An observational study of 663 caregivers and the patients with dementia they care for suggests caregiver depression is associated with increased emergency department visits for their patients. A total of 84 caregivers had depression at the study start and it was associated with an increase in rates of emergency department use by patients after accounting for a number of other potential mitigating factors including patient age and the severity of dementia. There were 196 patients with dementia who had at least one emergency department visit in the first six months of the study.
Bottom Line: This research letter reports on the association between the legalization of medical and recreational marijuana and teen marijuana use. Researchers used data from the Youth Risk Behavior Surveys from 1993 to 2017, when 27 states and Washington, D.C., contributed data to the survey before and after medical marijuana laws were adopted and seven states contributed data before and after recreational marijuana laws were adopted. More than 1.4 million high school students were included in the final study.
What The Study Did: This observational study used data from a survey of behavioral health that included students from 10 Los Angeles-area high schools to examine whether nonmedical prescription opioid use was associated with later risk of heroin use in adolescents.
Author: Adam M. Leventhal, Ph.D., of the University of Southern California in Los Angeles, is the corresponding author.
(doi:10.1001/jamapediatrics.2019.1750)
Scientists have pinpointed the "pace" and "shape" of life as the two key elements in animal life cycles that affect how different species get by in the world. Their findings, which come from a detailed assessment of 121 species ranging from humans to sponges, may have important implications for conservation strategies and for predicting which species will be the winners and losers from the global environment crisis.
Supercomputer simulations of galaxies have shown that Einstein's theory of General Relativity might not be the only way to explain how gravity works or how galaxies form.
Physicists at Durham University, UK, simulated the cosmos using an alternative model for gravity - f(R)-gravity, a so called Chameleon Theory.
The resulting images produced by the simulation show that galaxies like our Milky Way could still form in the universe even with different laws of gravity.
With little cases of ethanol to preserve tissue samples for total genomic DNA analysis, a trio covered much ground in the mountains of Japan and Korea to elucidate the evolution of the scorpionfly. The rugged scientists set out to use molecular phylogenetic analysis to show that the "alpine" type of scorpionfly and "general" type must be different species. After all, the alpine type exhibit shorter wings than the general type, and alpine type females also have very dark and distinct markings on their wings.
However, what they found in the DNA surprised them.
A global survey shows that a family of gut bacteria viruses called crAssphage is found in people - and their sewage - all over the world. Closely related viruses are found in monkeys and apes, so crAssphage has probably been with us for millions of years. These viruses are called phages, and they reproduce in bacterial cells, not in human cells. They make up the majority of gut viruses in healthy people. The work was published July 8 in the journal Nature Microbiology.
A new breakthrough has the potential to improve sensors used to test for diseases and detect doping in sports.
An international research team led by scientists from Lancaster University have created a coating only one molecule thick that modifies the surface of sensor electrodes.