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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Agencies
May 9,2020

17-year-old Pratyusha Jha, wakes up scrambling for newspapers these days to look for any news about her pending board exams and is anxious about what the future has in store for her.

Similar concerns are shared by Bipin Kumar, a class 12 student, who says the announcement of board exams from July 1 to 15 brought limited clarity as the larger questions remain unanswered.

The COVID-19 lockdown, came with a different set of concerns for class 12 students, whose board exams were postponed midway following the outbreak of coronavirus, putting on hold their future plans as well.

"Everyday I have been looking for news about the exams and about entrance exam dates. I feel unfortunate that this happened during the year I was supposed to take the big college leap. I don't want my future decisions to be shaped by this very year as what I opt to study now will remain with me lifelong," Pratyusha told PTI.

Ending some uncertainty for students, HRD Minister Ramesh Pokhriyal 'Nishank' on Friday announced that the pending class 10 and 12 board exams will be held from July 1 to 15. While class 12 exams will be conducted across the country, the class 10 exams are only pending in North East Delhi where they were affected due to the law and order situation.

"The anxiety doesn't end here, there is no date sheet yet. What will be the modalities of exams, how will we reach centres, what protocols have to be followed, there is no clarity on that. My friends and I keep calling our school teachers and also the CBSE helpline to seek some clarity," Bipin Kumar said.

Vaibhav Sharma, a class 12 student in Gurgaon said, "There is no clarity yet. I wanted to apply for DU, but now that the exams are taking place in July when will the results be declared, when will cut offs be announced. If I don't get a good college here, will I be able to travel to different cities for admission, nothing is known yet."

Similarly, for the students in northeast Delhi, the wait for the exams has become a "test of patience" as they were postponed first in the area due to law and order situation, and later due to the coronavirus outbreak, resulting in a four-month-long wait for the exams.

"It has become an endless wait and now I don't feel like studying too. Right from childhood, we are taught that board exams are too crucial and have to be focussed at least two years in advance. But now, it is a different picture altogether," Rani Kumari, a resident of Chandbagh said.

Universities and schools across the country have been closed and exams postponed since March 16 when the Centre announced a countrywide classroom shutdown as one of the measures to contain the COVID-19 outbreak.

Later, a nationwide lockdown was announced on March 24, which has now been extended till May 17.

The board was not able to conduct class 10 and 12 exams on eight examination days due to the coronavirus outbreak. Further, due to the law and order situation in North East Delhi, the board was not able to conduct exams on four examination days, while a very small number of students from and around this district were not able to appear in exams on six days.

The board had last month announced that it will only conduct pending exams in 29 subjects which are crucial for promotion and admission to higher educational institutions. The modalities of assessment for the subjects for which exams are not being conducted will be announced soon by the board.

The schedule has been decided in order to ensure that the board exams are completed before competitive examinations such as engineering entrance JEE-Mains, which is scheduled from July 18-23, and medical entrance exam NEET, which is scheduled on July 26.

The University Grants Commission (UGC) has issued guidelines to universities that new academic session for freshers will begin from September while for the existing students from August.

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Agencies
February 11,2020

Using smartphone for long hours every day may do you more harm than you can probably think of. Researchers have found that spending a lot of time with the device and on social media may lead to mental distress and suicidality among adolescents.

The findings, published in the journal CMAJ (Canadian Medical Association Journal) contains guidance for physicians, parents and teachers on how to help teenagers manage smartphone and social media use for a healthy balance between sleep, academic work, social activity, interpersonal relationships and online activity.

"Physicians, teachers and families need to work together with youth to decrease possible harmful effects of smartphones and social media on their relationships, sense of self, sleep, academic performance, and emotional well-being," said lead author of the study Elia Abi-Jaoude from Toronto Western Hospital in Canada.

This review of evidence, led by the Hospital for Sick Children (SickKids), focuses on smartphone use and does not consider online gaming.

"For adolescents today, who have not known a world without social media, digital interactions are the norm, and the potential benefits of online access to productive mental health information -- including media literacy, creativity, self-expression, sense of belonging and civic engagement -- as well as low barriers to resources such as crisis lines and Internet-based talking therapies cannot be discounted," the authors wrote.

The researchers recommend that doctors should ask teenagers to reduce social media use rather than eradicate it completely and encourage parents to be part of the conversations.

Parents should discuss appropriate smartphone use with teenagers to determine together how to reduce risks and set boundaries.

A recent poll from the US indicates that 54 per cent of teenagers think they spend too much time on their smartphones and about half said they were cutting back on usage.

"Encouragingly, youth are increasingly recognising the negative impact of social media on their lives and starting to take steps to mitigate it," the authors wrote.

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