TEXTO

Brazil has declared an end to its public health emergency over the Zika virus, 18 months after a surge in cases drew headlines around the world.

The mosquito-borne virus was not considered a major health threat until the 2015 outbreak revealed that Zika can lead to severe birth defects. One of those defects, microcephaly, causes babies to be born with skulls much smaller than expected.

Photos of babies with the defect spread panic around the globe as the virus was reported in dozens of countries. Many would-be travellers cancelled their trips to Zika-infected places. The concern spread even more widely when health officials said it could also be transmitted through sexual contact with an infected person.

The health scare came just as Brazil, the epicentre of the outbreak, was preparing to host the 2016 Olympics, fuelling concerns the Games could help spread the virus. One athlete, a Spanish wind surfer, said she got Zika while training in Brazil ahead ofthe Games.

In response to the outbreak, Brazil launched a mosquito-eradication campaign. The health ministry said those efforts have helped to dramatically reduce cases of Zika. Between January and mid-April, 95% fewer cases were recorded than during the same period last year. The incidence of microcephaly has fallen as well.

The World Health Organization (WHO) lifted its own international emergency in November, even while saying the virus remained a threat.

“The end of the emergency doesn’t mean the end of surveillance or assistance” to affected families, said Adeilson Cavalcante, the secretary for health surveillance at Brazil’s health ministry. “The health ministry and other organisations involved in this area will maintain a policy of fighting Zika, dengue and chikungunya.”

All three diseases are carried by the Aedes aegypti mosquito.

But the WHO has warned that Zika is “here to stay,” even when cases of it fall off, and that fighting the disease will be an ongoing battle.

(Fonte: Associated Press, Friday 12 May 2017 10.18 BST. Last modified on Friday 12 May 2017 22.00 BST)

T E X T

Can you learn in your sleep?

Sleep is known to be crucial for learning and memory formation. What's more, scientists have even managed to pick out specific memories and consolidate them during sleep. However, the exact mechanisms behind this were unknown — until now.

Those among us who grew up with the popular cartoon "Dexter's Laboratory" might remember the famous episode wherein Dexter's trying to learn French overnight. He creates a device that helps him to learn in his sleep by playing French phrases to him. Of course, since the show is a comedy, Dexter's record gets stuck on the phrase "Omelette du fromage" and the next day he's incapable of saying anything else. This is, of course, a problem that puts him through a series of hilarious situations.

The idea that we can learn in our sleep has captivated the minds of artists and scientists alike; the possibility that one day we could all drastically improve our productivity by learning in our sleep is very appealing. But could such a scenario ever become a reality?

New research seems to suggest so, and scientists in general are moving closer to understanding precisely what goes on in the brain when we sleep and how the restful state affects learning and memory formation.

For instance, previous studies have shown that non-rapid eye movement (non-REM) sleep — or dreamless sleep — is crucial for consolidating memories. It has also been shown that sleep spindles, or sudden spikes in oscillatory brain activity that canbe seen on an electroencephalogram (EEG) during the second stage of non-REM sleep, are key for this memory consolidation. Scientists were also able to specifically target certain memories and reactivate, or strengthen, them by using auditory cues.

However, the mechanism behind such achievements remained mysterious until now. Researchers were also unaware if such mechanisms would help with memorizing new information.

Therefore, a team of researchers set out to investigate. Scott Cairney, from the University of York in the United Kingdom, co-led the research with Bernhard Staresina, who works at the University of Birmingham, also in the U.K. Their findings were published in the journal Current Biology.

Cairney explains the motivation for the research, saying, "We are quite certain that memories are reactivated in the brain during sleep, but we don't know the neural processes that underpin this phenomenon." "Sleep spindles," he continues, "have been linked to the benefits of sleep for memory in previous research, so we wanted to investigate whether these brain waves mediate reactivation. If they support memory reactivation, we further reasoned that it could be possible to decipher memory signals at the time that these spindles took place."

To test their hypotheses, Cairney and his colleagues asked 46 participants "to learn associations between words and pictures of objects or scenes before a nap." Afterward, some of the participants took a 90-minute nap, whereas others stayed awake. To those who napped, "Half of the words were [...] replayed during the nap to trigger the reactivation of the newly learned picture memories," explains Cairney.

"When the participants woke after a good period of sleep," he says, "we presented them again with the words and asked them to recall the object and scene pictures. We found that their memory was better for the pictures that were connected to the words that were presented in sleep, compared to those words that weren't," Cairney reports.

Using an EEG machine, the researchers were also able to see that playing the associated words to reactivate memories triggered sleep spindles in the participants' brains. More specifically, the EEG sleep spindle patterns "told" the researchers whether the participants were processing memories related to objects or memories related to scenes.

"Our data suggest that spindles facilitate processing of relevant memory features during sleep and that this process boosts memory consolidation," says Staresina. "While it has been shown previously," he continues, "that targeted memory reactivation can boost memory consolidation during sleep, we now show that sleep spindles might represent the key underlying mechanism."

Cairney adds, "When you are awake you learn new things, but when you are asleep you refine them, making it easier to retrieve them and apply them correctly when you need them the most. This is important for how we learn but also for how we might help retain healthy brain functions."

Staresina suggests that this newly gained knowledge could lead to effective strategies for boosting memory while sleeping.

So, though learning things from scratch à la "Dexter's Lab" may take a while to become a reality, we can safely say that our brains continue to learn while we sleep, and that researchers just got a lot closer to understanding why this happens.

From: https://www.medicalnewstoday.com/articles/Mar/2018

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There is nothing conventional about 17-year-old Michael Fuller’s relationship with music. As someone with high-functioning autism who sees the world through sound, creating melodies from the bustle of the high street or trains on the tracks feels more natural than any social interaction. This hardwired connection to sound has been with him for as long as he can remember.

By the age of 11, Michael could play Mozart by ear, having taught himself to play the piano through a mobile phone app. The app highlighted notes on a keyboard as classical music played. He describes his unusual musical talent as “downloading” music into his head. His mother, Nadine, remembers that as a child Michael would “suddenly pop up and say: ‘I’ve got a symphony’”. Michael took to the piano and found he could quickly perform complex pieces from memory.

“I liked what I was hearing, sought more music and began studying through Google and YouTube,” he remembers. “It was very organic. I would listen in great depth and the music would be implanted in my mind. I could then just play it on the piano – all without being taught.”

Growing up in a family that listened to reggae over classical music, Michael feels “very much aware” of how different his approach is to music – symbolised by the way he taught himself piano as a child. This, his mother says, came as a “surprise to the family and myself – I’d never listened to classical music in my life”.

It was not long after learning to play the piano that Michael started composing his own works. Describing this process as “making music with my mind”, Michael says composing classical symphonies “helps me to express myself through music – it makes me calm”. Michael wants to nurture his song writing to achieve his ambition of becoming a modern mainstream classical artist. He wants to control the creative process, unlike typical modern-day composers, who he says “write blobs on a page, hand it over to the musicians – then say bye-bye and stay in the background and get no recognition”. Instead, Michael is determined to take centre stage.

(Alex Taylor. www.bbc.com, 27.03.2018. Adaptado.)

Hard Lesson in Sleep for Teenagers

By Jane E. Brody October 20, 2014

Few Americans these days get the hours of sleep optimal for their age, but experts agree that teenagers are more likely to fall short than anyone else.

Researchers report that the average adolescent needs eight and a half to nine and a half hours of sleep each night. However, in a poll taken in 2006 by the National Sleep Foundation, less than 20 percent reported getting that much rest on school nights. With the profusion of personal electronics, the current percentage is believed to be even worse. A study in Fairfax, Va., found that only 6 percent of children in the 10th grade and only 3 percent in the 12th grade get the recommended amount of sleep. Two in three teens were found to be severely sleep-deprived, losing two or more hours of sleep every night. The causes can be biological, behavioral or environmental. The effect on the well-being of adolescents — on their health and academic potential — can be profound.

Insufficient sleep in adolescence increases the risks of high blood pressure and heart disease, Type 2 diabetes and obesity, said Dr. Owens, pediatric sleep specialist at Children's National Health System in Washington. Sleeplessness is also linked to risk-taking behavior, depression, suicidal ideation and car accidents. Insufficient sleep also impairs judgment, decision-making skills and the ability to curb impulses, which are "in a critical stage of development in adolescence," Dr. Owens said. With the current intense concern about raising academic achievement, it is worth noting that a study by Kyla Wahlstrom of 9,000 students in eight Minnesota public high schools showed that starting school a half-hour later resulted in an hour's more sleep a night and an increase in the students' grade point averages and standardized test scores.

When children reach puberty, a shift in circadian rhythm makes it harder for them to fall asleep early enough to get the requisite number of hours and still make it to school on time. A teenager’s sleep-wake cycle can shift as much as two hours, making it difficult to fall asleep before 11 p.m. If school starts at 8 or 8:30, it is not possible to get enough sleep. Based on biological sleep needs, a teenager who goes to sleep at 11 p.m, should be getting up around 8 a.m.

Adding to the adolescent shift in circadian rhythm are myriad electronic distractions that cut further into sleep time, like smartphones, iPods, computers and televisions. A stream of text messages, tweets, and postings on Facebook and Instagram keep many awake long into the night.

Parents should consider instituting an electronic curfew and perhaps even forbid sleep-distracting devices in the bedroom, Dr . Owens said. Beyond the bedroom, many teenagers lead overscheduled lives that can lead to short nights.

Also at risk are many teenagers from low-income and minority families, where overcrowding, excessive noise and safety concerns can make it difficult to get enough restful sleep, the academy statement said. Trying to compensate for sleep deprivation on weekends can further compromise an adolescent's sleep-wake cycle by inducing permanent jet lag. Sleeping late on weekends shifts their internal clock, making it even harder to get to sleep Sunday night and wake up on time for school Monday morning.

(Adapted and abridged from http://www.nytimes.com)