Mosquitoes remember human smells, but also swats: study

Agencies
January 30, 2018

New York, Jan 28: Your grandmother's insistence that you receive more bug bites because you are 'sweeter' may not be that far-fetched as a study claims that mosquitoes can rapidly learn and remember the smells of hosts.

Researchers at Virginia Polytechnic Institute and State University in the US said dopamine is a key mediator of this process.

Mosquitoes use this information and incorporate it with other stimuli to develop preferences for a particular vertebrate host species, and, within that population, certain individuals, they said.

However, the study also proved that even if an individual is deemed delicious-smelling, a mosquito's preference can shift if that person's smell is associated with an unpleasant sensation.

Hosts who swat at mosquitoes or perform other defensive behaviours may be abandoned, no matter how sweet they are, according to the study published in the journal Current Biology.

The researchers said mosquitoes exhibit a trait known as aversive learning by training female aedes aegypti mosquitoes to associate odours (including human body odours) with unpleasant shocks and vibrations.

Aedes aegypti mosquitoes are vectors for Zika fever, dengue fever, chikungunya, and yellow fever viruses, and can be found in tropical and subtropical regions throughout the world.

Twenty-four hours later, the same mosquitoes were assessed in a Y-maze olfactometer in which they had to fly upwind and choose between the once-preferred human body odour and a control odour.

The mosquitoes avoided the human body odour, suggesting that they had been successfully trained.

By taking a multidisciplinary approach and using cutting-edge techniques, including CRISPR gene editing and RNAi, the scientists were also able to identify that dopamine is a key mediator of aversive learning in mosquitoes.

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Agencies
July 25,2020

The COVID-19 pandemic and the subsequent lockdown saw many people turning chefs overnight, but those who could not turned to online delivery of food. And not just any food, as per a new report, Indians "craved the most for Biryani" during the lockdown.

The "StatEATistics report: The Quarantine Edition" from food delivery platform Swiggy found that Indians ordered biryani over "5.5 lakh times" from their favourite restaurants.

The new normal might have opened a pandora's box of behavioral changes, but some old habits die hard like the love for Biryani, which took the top spot for overall orders. It was followed by butter naan and masala dosa at 3,35,185 and 3,31,423, respectively.

Biryani has topped the list of most ordered dishes for the fourth year in a row, the food delivery platform noted.

Indians didn't forget to indulge their sweet tooth in the uncertain months of lockdown. Their favourite comfort food during the lockdown period was the moist and decadent Choco Lava cake, ordered around 1,29,000 times.

"The humble Gulab Jamun (84,558) and chic Butterscotch Mousse cake (27,317) followed suit," said the report derived from Swiggy's order analysis in the past few months across cities that it is present in.

Also, as birthday parties moved to video calls, and virtual cake cutting sessions, according to the food delivery platform, it delivered nearly "1,20,000 cakes" to complete these celebrations.

According to the report, on average, "65,000 meal orders" were placed by 8 pm each day to make sure food arrived in time for dinner.

"It was the busiest hour for Swiggy delivery partners and restaurants. On average, they (customers) chose to tip Rs.23.65, with one particularly generous customer tipping Rs. 2500!," it added.

For those who only relied on home-made food during the quarantine, Swiggy delivered a whooping 323 million kgs of onions and 56 million kgs of bananas through its grocery section and hence ensured that its consumers were all stocked up.

That said, it also took care of the 'quick-fix meal' tribe -- consumers who resort to the evergreen college hacks of living on instant noodles.

"Around 3,50,000 packets of this ideal easy to cook meal were ordered during the lockdown," it said.

In all, Swiggy delivered 40 million orders across food, groceries, medicines and other household items during India's lockdowns. It also delivered over 73,000 bottles of sanitizers and hand wash along with 47,000 face masks as the definition of essentials' changed during these uncertain times.

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News Network
March 6,2020

Mar 6: The spread of the new coronavirus is shining the spotlight on a little-discussed gender split: men wash their hands after using the bathroom less than women, years of research and on-the-ground observations show.

Health officials around the world advise that deliberate, regular handwashing is one of the best weapons against the virus which causes a flu-like respiratory illness that can kill and has spread to around 80 countries.

The Centers for Disease Control and Prevention's online fact sheet "Handwashing: A corporate activity," cites a 2009 study that finds "only 31% of men and 65% of women washed their hands" after using a public restroom.

Social media comments about men's handwashing lapses forced an august British institution to caution visitors about bathroom behaviour this week.

After author Sathnam Sanghera complained on Twitter about "grown," "educated" men in the British Library toilets not washing their hands, the library responded, putting up additional signs reminding patrons to wash their hands in men's and women's bathrooms.

Thanks to "visitor feedback," a spokesman told Reuters, "we have increased further the number of posters in public toilets so that visitors are reminded of the importance of good hygiene at exactly the point where they can wash their hands."

Men and women approach handwashing after using the restroom differently, according to multiple surveys and field studies.

"Women wash their hands significantly more often, use soap more often, and wash their hands somewhat longer than men," according to a 2013 Michigan State University field study conducted by research assistants who observed nearly 4,000 people in restrooms around East Lansing, Michigan.

The study found 14.6% of men did not wash their hands at all after using the bathroom and 35.1% wet their hands but did not use soap, compared to 7.1% and 15.1% of women, respectively.

"If you stand in the men's bathroom at work, and watch men leave, they mostly don't wash their hands if they used the urinal," said one New York City public relations executive, who did not want to be identified for fear of alienating his colleagues.

Since the virus's spread, he's seen an uptick in men's handwashing at work, he noted. "I, for the record, do wash my hands all the time," he added.

Female medical staff in critical care units "washed their hands significantly more often than did their male counterparts after patient contact," a 2001 study published in the American Journal of Infection Control found.

Middle-aged women with some college education had the highest level of knowledge about hand hygiene, a survey published in 2019 by BMC Public Health, an open access public health journal, found.

Early information about coronavirus infection in China shows that men may be more susceptible to the disease. Just over 58% of the more than 1,000 COVID-19 patients reported in China through Jan. 29, 2020, were male, research published in the New England Journal of Medicine shows.

Researchers have not linked the difference to hand hygiene.

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News Network
March 5,2020

Bergen, Mar 5: Divorce of parents may impact the academics of children negatively, suggests a new study.

According to the study, parental divorce is associated with a lower grade point average (GPA) among adolescents, with a stronger association seen in teens with more educated mothers.

The study was published in the journal PLOS ONE.

Children and adolescents with divorced or separated parents are known to do less well in school than adolescents with nondivorced parents and to be less well-adjusted, on average, across a spectrum of physical and mental health outcomes.

In the new study, researchers used data from the youth@hordaland study, a population-based survey of adolescents aged 16-19 conducted in the spring of 2012 in Hordaland County, Norway.

19,439 adolescents were invited to participate and 10,257 agreed; of those, 9,166 are included in the current study.

Overall, adolescents with divorced parents had a 0.3 point lower GPA (standard error 0.022, p<0.01) than their peers.

Controlling for parental education reduced the effect by 0.06 points to 0.240 (SE 0.021, p<0.01). This heterogeneity was predominantly driven by maternal education levels, the researchers found.

After controlling for paternal education and income measures, divorce was associated with a 0.120 point decrease in GPA among adolescents whose mothers had a secondary school education level; a 0.175 point decrease when mothers had a Bachelor's level education; and a 0.209 point decrease when mothers had a Master's or PhD level education (all estimates relative to adolescents with a mother who had a basic level of education, such as ISCED 0-2).

Due to the cross-sectional structure of the study, researchers could not investigate specific changes between pre- and post-divorce family life, and future studies are needed to investigate potential mechanisms (such as reduced parental monitoring or school-involvement) which might drive this finding.

Nonetheless, this study provides new evidence that the negative association between divorce and teens' GPA is especially strong in families with more educated mothers.

"Among Norwegian adolescents, parental divorce was hardly associated with GPA among youth whose parents have low educational qualifications. In contrast, among adolescents with educated or highly educated mothers, divorce was significantly associated with lower GPA," said the authors.

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