GMAT

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

Information is the essence of universe and means distinction between things. It is the very basic principle of physics that distinctions never disappear even though they might get scrambled or mixed away even after a seemingly irreversible change – say a magazine gets dissolved into pulp at a recycling plan, the information on the pages of the magazines will be re-organized and not eliminated and in theory the decay can be reversed; the pulp reconstructed into words and photographs. The only exception to this principle in physics is if the magazine were thrown into a black hole, a singular object in this regard, since nothing can emerge out of it after all. Even after Stephen Hawking showed in 1975 that black holes can radiate away matter and energy, the radiation seemed devoid of any structure, indicating that all information is lost in a black hole – a conclusion that has been hotly contested by physicists all over the world who argue that the entire structure of theoretical physics will disintegrate once you accept the notion that information can be lost, even if in a black hole.

Even though Hawking was not easily convinced, the physicists adopted a new theory called the holograph principle that states that when an object falls inside a black hole the stuff inside it may be lost but the objects information may be imprinted on the surface of black hole and with the right tools you may reconstruct the magazine from the black hole just as you would have reconstructed it from the pulp. This principle which may sound like an accounting trick has some serious implications if true. It implies that all information about 3 dimensional objects is stored in 2 dimensions and that there is a limit to how much information can be stored on a given surface area.  While this theory plugs a key gap in Hawkins assertion its corollaries spring some interesting implications that may have a tough time standing up to the scrutiny.

According to the passage, prior to 1975 it was believed that black holes were unique because:

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

Although the journal Social Text was never at the forefront of publishing articles on feminism and never debated whether capitalism was the source of women’s oppression in 1970s or whether male supremacy was itself a systematic form of domination, it is not clear whether social feminist’s classification of the journal as the one run by “boy’s club” could have been completely justified till recently. There could have been many reasons that the journal’s mission statement as set out in its first prospectus in 1979 did not take notice of the burning issues feminists were then discussing. May be triumvirate of founding editors were too focused on Marxist high theory to consider gender alongside economic class as an important mode of social organization and oppression, or on the other hand they may have simply chosen on purpose to not include feminism specifically in its charter.

The recent paper by Rosa Luxemburg suggests that the first prospectus contained the seeds of its own feminist undoing. The founders demarcated fields of focus for the journal that could hardly be explored without attention to gender, sexuality, and the historical experiences of women. They were rather interested in “everyday life,” “mass culture,” and “consumer society”. Hence, the little feminist work that appears in Social Text is in the realm of cultural analysis not revolutionary praxis and is often buried in the back of the journal in “Unequal Developments,” the section that offers reviews and experimental writing.

 

For example, in the second edition of the journal in the section Unequal Developments, Christine Holmland performs a thorough feminist dissection of the then-current Disney film ‘The North Avenue Irregulars’, showing how this comedy about a group of church ladies who take on the local mafia superficially celebrates, but finally deflates the idea of women’s activism, and along the way reinforces gendered roles at every level of social life.

Why does the author cite Christine Holmland’s example to?

The institute’s lead trainer, whose subject expertise, views on the questions on the test, and problem-solving style were impressive to the students who worked with her, was also acknowledged as a leading strategist by many people outside her firm, including teachers at rival institutes, whose approaches often differed substantially from her own. 

Fast food chains constantly face the problem of low employee retention, to counter which the companies offer high salaries. The companies have come up with the solution of hiring retired people who have a very low attrition rate. However, their time taken to service an order is more and they require going through long training programs at regular intervals. Thus, for most fast food chains the gain in employee retention does not compensate for the increase in time taken to serve each customer. Nevertheless, since the customers continue to be more appreciative when served by retired people, their employment is likely to become an industry-wide feature.

In the argument above, the two portions in boldface play which of the following roles?

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

Every day, Tom walks from his home to his office, via the same route, covering s feet at a speed of x feet per minute. Today he took a different route and ended up walking 10% more than he usually does, at a speed that was 100 meters per minute faster than his usual speed. What is the percentage change in the time he took today compared to the time he takes on a usual day? (1 feet =0.3 meter)  

The residents of the city of Tibica are supplied water by two local corporations: TMC (Tibica Municipal Corporation) and TWMC (TibicaWater Management Corporation). Under pressure from the government, TMC recently increased its supply of water to the city. Even though TWMC maintained its supply level, the residents complained that their overall supply of water has reduced. Therefore, it seems likely that

Which of the following statements best completes the above passage?

TV is the future because it remains king of all media. While handsets get hyped, the typical U.S. consumer watches more than 5 hours of TV a day, according to Nielsen, and even younger adults 18 to 24 years old—the supposed digital generation—spend 3 hours and 30 minutes on televisions daily compared to only 49 minutes on the Web and 20 minutes on mobile. 

The above argument is most vulnerable to which of the following criticisms?

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