Todas as questões do ENEM

                                         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 can be 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

O Reino Fungi compreende seres particulares, dentre os quais o mofo que ataca os alimentos, os cogumelos comestíveis utilizados em diversas receitas culinárias e o penicilium associado à produção de antibióticos. Com relação aos fungos, analise as proposições abaixo.

I. São organismos eucariontes, unicelulares ou pluricelulares, exclusivamente heterotróficos.

II. Nos fungos pluricelulares, o glicogênio é o material de reserva, mas nos unicelulares o amido é que cumpre essa função energética.

III. Realizam sua nutrição através de digestão extracorpórea, liberando, no ambiente, enzimas digestivas que transformam macromoléculas em moléculas menores.

IV. Reproduzem-se, apenas, assexuadamente por meio de esporos, formados em estruturas denominadas esporângios, ascos e basídios.

Está correto o que se afirma somente em

Question: Is there anything I can do to train my body to need less sleep?

Karen Weintraub

June 17, 2016

   Many people think they can teach themselves to need less sleep, but they’re wrong, said Dr. Sigrid Veasey, a professor at the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania’s Perelman School of Medicine. We might feel that we’re getting by fine on less sleep, but we’re deluding ourselves, Dr. Veasey said, largely because lack of sleep skews our self-awareness. “The more you deprive yourself of sleep over long periods of time, the less accurate you are of judging your own sleep perception,” she said.

   Multiple studies have shown that people don’t functionally adapt to less sleep than their bodies need. There is a range of normal sleep times, with most healthy adults naturally needing seven to nine hours of sleep per night, according to the National Sleep Foundation. Those over 65 need about seven to eight hours, on average, while teenagers need eight to 10 hours, and school-age children nine to 11 hours. People’s performance continues to be poor while they are sleep deprived, Dr. Veasey said.

   Health issues like pain, sleep apnea or autoimmune disease can increase people’s need for sleep, said Andrea Meredith, a neuroscientist at the University of Maryland School of Medicine. A misalignment of the clock that governs our sleep-wake cycle can also drive up the need for sleep, Dr. Meredith said. The brain’s clock can get misaligned by being stimulated at the wrong time of day, she said, such as from caffeine in the afternoon or evening, digital screen use too close to bedtime, or even exercise at a time of day when the body wants to be winding down.

(http://well.blogs.nytimes.com. Adaptado.)

    No fim da carta de que V. M.1 me fez mercê me manda V. M. diga meu parecer sobre a conveniência de haver neste estado ou dois capitães-mores ou um só governador.

    Eu, Senhor, razões políticas nunca as soube, e hoje as sei muito menos; mas por obedecer direi toscamente o que me parece.

    Digo que menos mal será um ladrão que dois; e que mais dificultoso serão de achar dois homens de bem que um. Sendo propostos a Catão dois cidadãos romanos para o provimento de duas praças, respondeu que ambos lhe descontentavam: um porque nada tinha, outro porque nada lhe bastava. Tais são os dois capitães-mores em que se repartiu este governo: Baltasar de Sousa não tem nada, Inácio do Rego não lhe basta nada; e eu não sei qual é maior tentação, se a 1 , se a 2 . Tudo quanto há na capitania do Pará, tirando as terras, não vale 10 mil cruzados, como é notório, e desta terra há-de tirar Inácio do Rego mais de 100 mil cruzados em três anos, segundo se lhe vão logrando bem as indústrias.

    Tudo isto sai do sangue e do suor dos tristes índios, aos quais trata como tão escravos seus, que nenhum tem liberdade nem para deixar de servir a ele nem para poder servir a outrem; o que, além da injustiça que se faz aos índios, é ocasião de padecerem muitas necessidades os portugueses e de perecerem os pobres. Em uma capitania destas confessei uma pobre mulher, das que vieram das Ilhas, a qual me disse com muitas lágrimas que, dos nove filhos que tivera, lhe morreram em três meses cinco filhos, de pura fome e desamparo; e, consolando-a eu pela morte de tantos filhos, respondeu-me: “Padre, não são esses os por que eu choro, senão pelos quatro que tenho vivos sem ter com que os sustentar, e peço a Deus todos os dias que me os leve também.”

    São lastimosas as misérias que passa esta pobre gente das Ilhas, porque, como não têm com que agradecer, se algum índio se reparte não lhe chega a eles, senão aos poderosos; e é este um desamparo a que V. M. por piedade deverá mandar acudir.

    Tornando aos índios do Pará, dos quais, como dizia, se serve quem ali governa como se foram seus escravos, e os traz quase todos ocupados em seus interesses, principalmente no dos tabacos, obriga-me a consciência a manifestar a V. M. os grandes pecados que por ocasião deste serviço se cometem.

(Sérgio Rodrigues (org.). Cartas brasileiras, 2017. Adaptado.)

1V. M.: Vossa Majestade.

                                         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 can be 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

Question: Is there anything I can do to train my body to need less sleep?

Karen Weintraub

June 17, 2016

   Many people think they can teach themselves to need less sleep, but they’re wrong, said Dr. Sigrid Veasey, a professor at the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania’s Perelman School of Medicine. We might feel that we’re getting by fine on less sleep, but we’re deluding ourselves, Dr. Veasey said, largely because lack of sleep skews our self-awareness. “The more you deprive yourself of sleep over long periods of time, the less accurate you are of judging your own sleep perception,” she said.

   Multiple studies have shown that people don’t functionally adapt to less sleep than their bodies need. There is a range of normal sleep times, with most healthy adults naturally needing seven to nine hours of sleep per night, according to the National Sleep Foundation. Those over 65 need about seven to eight hours, on average, while teenagers need eight to 10 hours, and school-age children nine to 11 hours. People’s performance continues to be poor while they are sleep deprived, Dr. Veasey said.

   Health issues like pain, sleep apnea or autoimmune disease can increase people’s need for sleep, said Andrea Meredith, a neuroscientist at the University of Maryland School of Medicine. A misalignment of the clock that governs our sleep-wake cycle can also drive up the need for sleep, Dr. Meredith said. The brain’s clock can get misaligned by being stimulated at the wrong time of day, she said, such as from caffeine in the afternoon or evening, digital screen use too close to bedtime, or even exercise at a time of day when the body wants to be winding down.

(http://well.blogs.nytimes.com. Adaptado.)

As enzimas são proteínas que têm como função acelerar as reações metabólicas que ocorrem nas células. Algumas enzimas necessitam de um componente químico adicional denominado cofator. Os cofatores podem ser íons inorgânicos ou moléculas orgânicas.

O quadro a seguir apresenta a configuração de alguns átomos neutros que, na forma iônica, servem como cofator para enzimas.

A enzima que terá como cofator um cátion bivalente de menor tamanho é a(o)

Question: Is there anything I can do to train my body to need less sleep?

Karen Weintraub

June 17, 2016

   Many people think they can teach themselves to need less sleep, but they’re wrong, said Dr. Sigrid Veasey, a professor at the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania’s Perelman School of Medicine. We might feel that we’re getting by fine on less sleep, but we’re deluding ourselves, Dr. Veasey said, largely because lack of sleep skews our self-awareness. “The more you deprive yourself of sleep over long periods of time, the less accurate you are of judging your own sleep perception,” she said.

   Multiple studies have shown that people don’t functionally adapt to less sleep than their bodies need. There is a range of normal sleep times, with most healthy adults naturally needing seven to nine hours of sleep per night, according to the National Sleep Foundation. Those over 65 need about seven to eight hours, on average, while teenagers need eight to 10 hours, and school-age children nine to 11 hours. People’s performance continues to be poor while they are sleep deprived, Dr. Veasey said.

   Health issues like pain, sleep apnea or autoimmune disease can increase people’s need for sleep, said Andrea Meredith, a neuroscientist at the University of Maryland School of Medicine. A misalignment of the clock that governs our sleep-wake cycle can also drive up the need for sleep, Dr. Meredith said. The brain’s clock can get misaligned by being stimulated at the wrong time of day, she said, such as from caffeine in the afternoon or evening, digital screen use too close to bedtime, or even exercise at a time of day when the body wants to be winding down.

(http://well.blogs.nytimes.com. Adaptado.)

    No fim da carta de que V. M.1 me fez mercê me manda V. M. diga meu parecer sobre a conveniência de haver neste estado ou dois capitães-mores ou um só governador.

    Eu, Senhor, razões políticas nunca as soube, e hoje as sei muito menos; mas por obedecer direi toscamente o que me parece.

    Digo que menos mal será um ladrão que dois; e que mais dificultoso serão de achar dois homens de bem que um. Sendo propostos a Catão dois cidadãos romanos para o provimento de duas praças, respondeu que ambos lhe descontentavam: um porque nada tinha, outro porque nada lhe bastava. Tais são os dois capitães-mores em que se repartiu este governo: Baltasar de Sousa não tem nada, Inácio do Rego não lhe basta nada; e eu não sei qual é maior tentação, se a 1 , se a 2 . Tudo quanto há na capitania do Pará, tirando as terras, não vale 10 mil cruzados, como é notório, e desta terra há-de tirar Inácio do Rego mais de 100 mil cruzados em três anos, segundo se lhe vão logrando bem as indústrias.

    Tudo isto sai do sangue e do suor dos tristes índios, aos quais trata como tão escravos seus, que nenhum tem liberdade nem para deixar de servir a ele nem para poder servir a outrem; o que, além da injustiça que se faz aos índios, é ocasião de padecerem muitas necessidades os portugueses e de perecerem os pobres. Em uma capitania destas confessei uma pobre mulher, das que vieram das Ilhas, a qual me disse com muitas lágrimas que, dos nove filhos que tivera, lhe morreram em três meses cinco filhos, de pura fome e desamparo; e, consolando-a eu pela morte de tantos filhos, respondeu-me: “Padre, não são esses os por que eu choro, senão pelos quatro que tenho vivos sem ter com que os sustentar, e peço a Deus todos os dias que me os leve também.”

    São lastimosas as misérias que passa esta pobre gente das Ilhas, porque, como não têm com que agradecer, se algum índio se reparte não lhe chega a eles, senão aos poderosos; e é este um desamparo a que V. M. por piedade deverá mandar acudir.

    Tornando aos índios do Pará, dos quais, como dizia, se serve quem ali governa como se foram seus escravos, e os traz quase todos ocupados em seus interesses, principalmente no dos tabacos, obriga-me a consciência a manifestar a V. M. os grandes pecados que por ocasião deste serviço se cometem.

(Sérgio Rodrigues (org.). Cartas brasileiras, 2017. Adaptado.)

1V. M.: Vossa Majestade.

TEXT

      Hundreds of studies have assessed leadership styles, mainly by having employees report on how their managers typically behave. Researchers have also collected information on how effective managers are. After large numbers of such studies became available, reviewers aggregated them quantitatively to discover what kinds of leadership are effective.

      One conclusion that has emerged based on the research of the past 30 years is that a hybrid style known as transformational leadership is highly effective in most contemporary organizational contexts.

      A transformational leader acts as an inspirational role model, motivates others to go beyond the confines of their job descriptions, encourages creativity and innovation, fosters good human relationships, and develops the skills of followers. This type of leadership is effective because it fosters strong interpersonal bonds based on a leader’s charisma and consideration of others. These bonds enable leaders to promote high-quality performance by encouraging workers rather than threatening them, thus motivating them to exceed basic expectations.

      By bringing out the best in others, transformational leaders enhance the performance of groups and organizations.

      Transformational leadership is androgynous because it incorporates culturally masculine and feminine behaviors. This androgynous mixing of the masculine and feminine means that skill in this contemporary way of leading does not necessarily come naturally. It may require some effort and thought.

      Men often have to work on their social skills and women on being assertive enough to inspire others. It is nonetheless clear that both women and men can adapt to the demands of leadership in the transformational mode.

      One of the surprises of research on transformational leadership is that female managers are somewhat more transformational than male managers. In particular, they exceed men in their attention to human relationships. Also, in delivering incentives, women lean toward a more positive, reward-based approach and men toward a more negative and less effective, threat-based approach. In these respects, women appear to be better leaders than men, despite the double standard that can close women out of these roles.

      Why are women leaders more transformational when they are less likely to become leaders in the first place? One reason is that the double standard that slows women’s rise would work against mediocre women while allowing mediocre men to rise. As a consequence, the women who attain leadership roles really are better than the men on average.

      It is also true women generally avoid more domineering, “command and control” behavior because of the backlash they receive if they lead in this way. Men can often get away with autocratic behavior that is roundly disliked in women. Ironically, this backlash against domineering women may foster good leadership because the androgynous middle ground is more likely to bring success. Leaders gain less from ordering others about than from forming teams of smart, motivated collaborators who together figure out how to solve problems and get work done.

From: http://www.nytimes.com/ 2013/03/20  

As to the leadership pattern that requires attitudes based on features of both male and female behaviors, one may infer that it