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El Nino may trigger frequent extreme weather events from 2040s: Study

El Nino may trigger frequent extreme weather events from 2040s: Study

In less than two decades from now, extreme weather events like intense heat waves and rainfall events triggered by El Nino are set to increase, a new study has shown.

El Nino is the unusual warming of ocean waters along the eastern equatorial Pacific Ocean. It is known to affect the monsoon and cause intense heat and droughts globally. In recent years, the 2015 El Nino event has significantly affected India’s rainfall, crop output and, thus, the overall economy.

In this study, researchers from the University of Exeter, UK have tried to calculate the ‘time of emergence’ of changes along the tropical Pacific Ocean under four possible carbon emissions scenarios. They concluded that drastic rainfall changes were on the cards starting in the 2040s.

“When looking at changes in El Nino rainfall patterns, the best estimate of the time of emergence of changes converges on 2040 in all of the four emissions scenarios considered,” the study published in the peer-reviewed scientific journal Nature Climate Change noted.

Normally, the India Meteorological Department (IMD) observes a weaker monsoon over India during El Nino years, even though the Met agency says that there is no one-on-one association between the two.

During 1951 – 2021, 15 years have been dominated by El Nino, including 2015, 2009, 2004, 2002, 1997, 1991, 1987, 1982, 1972, 1969, 1965, 1963, 1957, 1953 and 1951. Of these, nine summer monsoon seasons over the country recorded deficient rain by more than 90 per cent (of the Long Period Average or LPA of 88cm for the country for June-September). During one of the strongest El Nino years in 1997, however, India’s seasonal rain was over 100 per cent of the LPA, the IMD data showed.

Earlier this month, the IMD said that a weak La Nina – the opposite phenomenon of El Nino when the equatorial Pacific remains cooler than normal – has been shown to favour Indian summer monsoons. As per the latest forecasts, the existing La Nina will turn the El Nino Southern Oscillation (ENSO) neutral sometime during the upcoming monsoon season.

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Binge drinking during sporting events and holidays may trigger A-fib

Binge drinking during sporting events and holidays may trigger A-fib

San Francisco — Chicken wings and chili aren’t the only potential overindulgences to be careful about on Super Bowl Sunday. Researchers at the University of California, San Francisco, are warning that excessive alcohol consumption during major sporting events and holidays may increase your risk of an episode of atrial fibrillation – an abnormal heart rhythm that can trigger serious health problems.

The researchers analyzed data from more than 36,000 people from all 50 U.S. states and 59 countries whose breath alcohol concentration was tracked via Bluetooth-enabled breathalyzer tests. Findings show that the participants drank more alcohol on eight national holidays/events or dates that coincided with major televised sporting events: New Year’s Day, the Fourth of July, Christmas, Martin Luther King Jr. Day, Father’s Day, the beginning of daylight saving time, the FIFA World Cup and Super Bowl Sunday.

The researchers then examined data from the California Office of Statewide Health Planning and Development, identifying emergency room visits related to a-fib coded between Jan. 1, 2005, and Dec. 30, 2015. After comparing the data for the weeks associated with increased alcohol consumption with other weeks of the year, the researchers found a “significantly elevated number of hospital visits” for a-fib occurred around the eight previously identified holidays/events, according to a UCSF press release.

 

“Our new data suggest that acute alcohol consumption in the general population is associated with a higher risk of an episode of atrial fibrillation, including a higher risk for a first episode of atrial fibrillation among individuals never previously diagnosed with the condition,” Gregory Marcus, senior study author and UCSF professor of medicine, said in the release. “Worldwide, alcohol is the most popularly consumed drug, and it now is clear that alcohol consumption is an important risk factor for atrial fibrillation.”

The study was published online Jan. 12 in the journal Nature Cardiovascular Research.

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Biological events occurring during puberty trigger sex differences in learning and memory

Biological events occurring during puberty trigger sex differences in learning and memory

New research from the University of California, Irvine reveals that sex differences in learning and memory mechanisms are triggered by biological events occurring during puberty. Findings show prepubescent female rodents have much better hippocampal long-term potentiation (LTP) and spatial learning than same-age males, but puberty has opposite consequences for synaptic plasticity in the two sexes.

The study, titled “Prepubescent female rodents have enhanced hippocampal LTP and learning relative to males, reversing in adulthood as inhibition increases” was recently published in Nature Neuroscience.

Since the late 19th century, the general consensus in the scientific community has been that men outperform women on spatial tasks, while women excel in learning tasks involving verbal material, while the general debate has been about why there is a difference.

The surprising conclusion from our results is that the polarization of sex differences in hippocampal synapses and related learning reverses in females and males from before to after puberty. This occurs because of distinct developmental changes. Thresholds for plasticity and encoding spatial information increase in females and decease in males.”


Christine Gall, PhD, co-corresponding author, and distinguished professor and chair of anatomy and neurobiology at the UCI School of Medicine

Puberty is a critical landmark in brain maturation and results in a wide variety of sex differences in behavior, but little is known about how it affects the substrates for memory encoding. Researchers identified a female-specific mechanism that increases the LTP threshold and decreases spatial memory from before to after puberty. Sex differences were demonstrated for hippocampus-dependent processes and driven by different underlying mechanisms.

In females only, inhibitory synapses in the CA1 field of the hippocampus exhibit an increase in levels of GABAA receptors containing the α5 subunit; this increase is associated with greater inhibition of synaptic activity critical for synaptic plasticity and memory. The α5 receptors have been linked to anxiety which also undergoes changes at the onset of the estrous cycle. Researchers found that pharmacological suppression of α5-GABAA receptors restored LTP and memory encoding in females to levels observed before puberty.

“Our team proposes that the emergent female pattern may favor learning in complex circumstances while the emergent male pattern favors rapid acquisition of simpler material. This idea suggests that optimal teaching strategies need to reflect previously unsuspected brain differences between the sexes and how these are dramatically adjusted during puberty,” Gall said. “The vast majority of studies have begun with analyses of young adult male rodents. Females use somewhat different memory mechanisms than do males and therefore may respond differently to drugs and gene mutations. This new research demonstrates the need for new sexually differentiated approaches for the development of therapeutic treatments and their applications at different life stages.”

Further research will be conducted to determine if the sex-specific LTP threshold changes identified in hippocampus during the transition to postpubertal life are evident in other brain areas and influence the encoding of different types of memories.

Source:

Journal reference:

Le, A.A., et al. (2022) Prepubescent female rodents have enhanced hippocampal LTP and learning relative to males, reversing in adulthood as inhibition increases. Nature Neuroscience. doi.org/10.1038/s41593-021-01001-5.