Sheetal Dhawan asked   •  3 hours ago

Researchers bet their bottom dollar on a combination of polar ice cores, tree-rings, geochemistry, and a medieval chronicle little-known in the West to solve one of vulcanology’s most enduring mysteries: which peak blew its top in the mid-13th century, causing a catastrophic eruption that ranks as one of the biggest in the recorded history? As with any investigation, the team had to rule out other suspects as it followed a trail of clues - and even read palms, or at least palm leaves, ultimately finding the culprit of the massive 1257 AD eruption, which the researchers say is Samalas volcano on Lombok Island in Indonesia.
For decades, scientists have been searching for the volcano responsible for the largest spike in sulfate deposits in the last 7,000 years, which were revealed in the ice cores from Greenland and Antarctica. The spike indicated a massive eruption around 1257 that may have sent up to eight times more sulfate into the stratosphere than the 1883 eruption of Karaktau, often held up as an archetype of volcanoes behaving badly. Researchers say the 1257 mystery spew is comparable in scope to a second-century AD eruption in the Taupo Volcanic Zone of New Zealand, known as the most intense historic volcanic event. Multitude of futile attempts for a few decades compelled the researchers to write the project off as “unsolved”. Some thirty years later, one of the researchers’ tips came from Babad Lombok, a 13th century historical record in Old Javanese, written on palm leaves, the chronicle referencing a massive eruption of Samalas that created an enormous caldera.The current research zeroed in on Samalas, part of the Mount Rinjani volcanic complex.
The team was able to accumulate a sizable amount of incriminating evidence, including pyroclastic deposits from the eruption more than 100 feet thick found more than 15 miles from the ruins of the volcano. The range of deposits and the volume suggest that the Samalas eruption exceeded that of the Tambora event in 1815. The team sampled carbonized tree trunks and branches in the Samalas deposit zone and used radiocarbon dating to confirm a mid 13th-century eruption. Reviewing wind patterns, researchers were even able to narrow the timeframe for the eruption. The distribution, to the west, of volcanic ash and other ejecta from Samalas suggest that the dry season’s easterly trade winds were prevalent, putting the eruption window between May and October of 1257.
The author of the passage alludes to the discovery made in Greenland and Antarctica in order to
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Aaditya Sharma asked   •  yesterday

Eating fish and other foods rich in omega-3 fatty acids could help people maintain healthy brains as they age as well as protect their hearts, new research suggests. Per this research, participants with low levels of omega-3 fatty acids in their blood had slightly smaller brains and scored lower on memory and cognitive tests than people with higher blood levels of omega-3s.
The researchers then looked at and ranked the level of omega-3 fatty acids in the participants' blood. People who scored in the bottom 25% in omega-3 fatty acid levels were compared with the rest of the study participants. Researchers found that those who had the lowest level of omega-3 fatty acid levels in their blood had lower brain gray matter volume compared with those with higher levels.
Gray matter volume is crucial to brain health. When it remains higher, brain health is being maintained. Decrease in gray matter volume indicates that brain cells are shrinking. The findings showed that consumption of baked or broiled fish on a weekly basis was positively associated with retention of gray matter volume in several areas of the brain. In fact the greater hippocampal, posterior cingulate, and orbital frontal cortex volumes obtained by optimal fish consumption led to reduced risk of contracting MCI or Alzheimer’s by almost five-fold.
The most recent U.S. dietary guidelines—released last year—recommend at least two servings of seafood a week. Some doctors and diet experts recommend that patients consume fish three times a week or take fish-oil supplements so they get enough omega-3 fatty acids to obtain health benefits.
The experiment discussed in paragraph 2 suggests
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Aaditya Sharma asked   •  4 days ago

The role of nurturing in determining one’s behavioral traits has been hotly contested. Historically, geneticists believed that behavioral traits are inherited. After all, many properties of the brain are genetically organized and don't depend on information coming in from the senses. Since active genes are essentially inherited, most traditional geneticists believe that nurturing environment plays little role in shaping one’s behavioral traits.
However, a new line of research indicated that methyl groups can activate dormant genes, bringing about a slew of changes much later in a person’s life. The methyl group works like a placeholder in a cookbook, attaching to the DNA within each cell to select only those recipes - er, genes - necessary for that particular cell’s proteins, telling the DNA what kind of cells to form.  The first such observation was in which methyl groups activated by causes ranging from exposure to certain chemicals to changes in diet set off a cascade of cellular changes resulting in cancer. Because methyl groups are attached to the genes, residing beside but separate from the double-helix DNA code, their study is dubbed epigenetics - “epi” referring to Greek for outer or above. 
Behavioral geneticists, encouraged by this discovery proved that traumatic experiences such as child neglect, drug abuse, or other severe stresses also set off epigenetic changes to the DNA inside the neurons of a person’s brain, permanently altering behavior.  Similarly, through multivariate analysis, they proved that identical twins, in scenarios where one twin has gone through a life altering event, can have vastly different reaction to a stressful situation.
The primary purpose of the passage is to
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Aaditya Sharma asked   •  5 days ago

Proverbial wisdom states that “birds of a feather flock together.”  Studies have shown that people of similar geographical and educational backgrounds and functional experience are extremely likely to found companies together.  Not considering spousal teams in the dataset, it has been found that a founding team is five times more likely to be all-male or all-female team.  Also, it is more likely to find founding teams that are remarkably homogenous with regard to skills and functional backgrounds.  

Homogeneity has important benefits. For the founder struggling to meet the challenges of a growing startup, selecting cofounders from among the people with whom he or she probably has important things in common is often the quickest and easiest solution. Not only does it generally take less time to find such people, but it also generally takes less time to develop effective working relationships with such similar people.  When founders share a background, they share a common language that facilitates communication, ensuring that the team begins the work relationship with a mutual understanding and hence can skip over part of the learning curve that would absorb the energies of people with very different backgrounds.  Increasing homogeneity may therefore be a particularly alluring- and, in some ways, a particularly sensible - approach for novice founders heading into unfamiliar territory.  Certainly, studies have found that the greater the heterogeneity among executive team members, the greater the risk of interpersonal conflict and the lower the group-level integration.  Even though it is very appealing to opt for the “comfortable” and “easy” decision to found with similar cofounders, by doing so founders may be causing long-term problems.  Teams with a wide range of pertinent functional skills may be able to build more valuable and enduring startups.  Conversely, homogenous teams tend to have overlapping human capital, making it more likely that the team will have redundant strengths and be missing critical skills.
From the passage, which of the following cannot be inferred as a benefit of homogenous teams?
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Ayush Lalchandani asked   •  2 weeks ago

Eating fish and other foods rich in omega-3 fatty acids could help people maintain healthy brains as they age as well as protect their hearts, new research suggests. Per this research, participants with low levels of omega-3 fatty acids in their blood had slightly smaller brains and scored lower on memory and cognitive tests than people with higher blood levels of omega-3s.
The researchers then looked at and ranked the level of omega-3 fatty acids in the participants' blood. People who scored in the bottom 25% in omega-3 fatty acid levels were compared with the rest of the study participants. Researchers found that those who had the lowest level of omega-3 fatty acid levels in their blood had lower brain gray matter volume compared with those with higher levels.
Gray matter volume is crucial to brain health. When it remains higher, brain health is being maintained. Decrease in gray matter volume indicates that brain cells are shrinking. The findings showed that consumption of baked or broiled fish on a weekly basis was positively associated with retention of gray matter volume in several areas of the brain. In fact the greater hippocampal, posterior cingulate, and orbital frontal cortex volumes obtained by optimal fish consumption led to reduced risk of contracting MCI or Alzheimer’s by almost five-fold.
The most recent U.S. dietary guidelines—released last year—recommend at least two servings of seafood a week. Some doctors and diet experts recommend that patients consume fish three times a week or take fish-oil supplements so they get enough omega-3 fatty acids to obtain health benefits.
The passage suggests the following about diet and gray matter volume
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