GMAT Exam Dumps - Admission Tests Graduate Management Admission Test Questions and Answers

Parasitic wasps propagate by injecting their eggs into a caterpillar that then becomes paralyzed as the eggs inside develop into wasp larvae. The wasp larvae kill the caterpillar host as they feed on it, form cocoons, and finally develop into wasps. In attempting to discover how such wasps detect the presence of the caterpillar hosts that are so critical to the wasps' propagation, researchers have uncovered an intriguing defense mechanism developed by the plants on which the caterpillars feed.

When chewed on, many plants release volatile compounds from both damaged and undamaged tissues. When these compounds are toxic to the insects that feed on the plants, they can help defend the plants from such attacks. However, the plants on which the wasps' caterpillar hosts feed have evolved an even more complex defense: the caterpillar-infested plants appear to release volatile chemicals that attract parasitic wasps, which then prey on the caterpillars. Scientists originally suspected that the wasps were attracted by an odor, reminiscent of cut grass, that is released as the caterpillar feeds, but a recent study suggests that a different set of volatile attractants is involved. In this study, when researchers used a razor blade to mimic caterpillar damage on the leaves, only grassy odors were emitted, not the volatile compounds that attracted wasps. However, when oral secretions from the caterpillars were applied to these damaged leaves, the leaves released the wasp attractants several hours later. Further tests revealed that oral secretions placed on the razor-damaged leaves stimulated the release of such attractants, making the plants as attractive to wasps as plants that had suffered actual caterpillar damage. These results suggest that chemicals from the caterpillar must be present for these attractants to be released and that unlike the grassy scent, which emanates only as the caterpillar on the plant, the wasp attractants are produced several hours after the attack and persist for several hours, perhaps days. Researchers have launched additional studies to determine whether the wasps' capacity to prey on caterpillars can be enhanced to the extent that the wasps could be used as a natural pesticide to "police" plants and protect them from crop-destroying caterpillars.

Although a substantial body of evidence Indicates that flexible and participative work arrangements make possible significant performance advantages over more traditional centralized and hierarchical structures, the proportion of businesses that have so transformed themselves remains quite small. Why, then, do firms that purport to be rationally acting organizations appear to resist the very methods that would best equip them to achieve their stated goals?

One line of analysis points toward the phenomenon of structural inertia, suggesting that organizations are "imprinted" with the conditions under which they were born, tending thereafter to ding to long-established routines, production methods, and identities. A second approach fastens on resistance to change among middle managers, who are said to view new work practices as threats to their traditional status and authority. A third approach suggests that because firms have tended to adopt innovations singly, rather than in clusters, the firms often fail to achieve far-reaching organization change.

Although each of these perspectives contains a partial truth, each one is limited. Analysis using the concept of structural inertia tends to emphasize the conservative aspects of organizational culture and to neglect inside factors as sources of change. While theories of managerial resistance have stressed the importance of within-firm political processes, they often endow upper levels of management with an omniscience and openness to egalitarian practices that upper-level managers do not possess. Finally, the last approach often views new practices as if they exist in a vacuum—as if they are unmediated by the manner in which they are introduced.

Soil salinization—the process by which soil acquires excess soluble salt, adversely affecting pasture or crop growth—is regarded as Australia's most serious environmental problem. Cope, whose 1958 investigation is considered the earliest survey of salt-affected areas in Victoria, hypothesized that surplus rainwater mobilized soluble salt stored in the permeable layer of soil, causing it to accumulate above an impermeable layer and then discharge downslope or onto a valley floor. In the late 1970s, however, Jenkin identified saline water underground as the main and immediate (though not ultimate) source of the salt, and hypothesized that the spread of salinity resulted from a rise in that groundwater. He attributed the rise to a decrease in coverage by water-absorbing trees and other vegetation at some ill-defined point in Australia's post-settlement history.

However, more-recent research suggests there was no rise in post-settlement groundwater levels. Furthermore, soil salinity probably antedated European settlement: early cartographic evidence indicates that some streams were saline when Europeans arrived. Dahlhaus suggests that salt accumulation resulted from marine incursions several million years ago, when parts of Victoria may have been submerged—as well as from transport of salt from the sea by wind and rain. Dahlhaus also notes that various minerals dissolved in groundwater by weathering may have produced salt.

Despite overall physiological bilateral symmetry, many species exhibit

lateralized biases, i.e., preferences for right- or left-oriented behavior. When

approaching prey, for example, some predator species favor their right eye; some

prey species respond more quickly when their left eye detects a predator. Similar

behavioral asymmetries occur in humans. Most notable is right- and lefthandedness; less notable is the tendency to turn right when entering a room.

Paul Farnsworth found that more successful students tended to choose seats near

the front, a little to the right. He argued that external factors such as teacher

location might have affected this lateral bias. But it is now known that processing

differences between the two brain hemispheres can also contribute to behavioral

asymmetries.

George Karev found that when presented with a movie theater seating

diagram, right-handed people were more likely than left-handed people to choose

a seat on the right, facing front. But he hypothesized that, since the right

hemisphere processes visuospatial and emotional information, the people who

chose right-side seats did so because that would put the screen in their left visual

field, optimizing information flow to the right hemisphere.

Although the right hemisphere is thought to be dominant in processing

emotion, some evidence suggests that the left hemisphere plays a role. The

valence model proposes that the left and right hemispheres process positive and

negative emotion respectively, while the approach-withdrawal model posits that

the left hemisphere processes emotion expressed in approach behavior and the

right hemisphere processes emotion expressed in withdrawal behavior.

Victoria Harms and colleagues suggested that since a paper seating plan was

used in the theater-seating studies by Karev and others, the exhibited preference

might be due simply to handedness: people choose the same side of the paper as

their favored hand. Consequently, the Harms research was designed to study

choices in an actual movie theater. Also, hoping to distinguish between various

explanations, they studied seating chaices for comedies (presumed to contain

positive emotional content), dramas (presumed to contain negative emotional

content), and documentaries (presumed to have balanced emotional content).

They found significant—though not universal—preference for seats on the right,

facing front, regardless of movie genre and of handedness.

The following is based on an article published in 2012.

Most linguists believe proto-Indo-European, the ancestor of all Indo-European

languages, was the language of chariot-driving pastoralists who spread through

Eurasia from steppes north of the Black Sea about 4,000 years ago. But a

competing theory is that proto-Indo-European was spoken by farmers in Anatolia

(Asia Minor) about 9,000 years ago, and spread from there along with agriculture.

To evaluate these hypotheses, researchers statistically compared IndoEuropean languages’ vocabularies. Languages with more similar vocabularies are

probably more closely related, sharing more recent common ancestors.

Combining the vocabulary statistics with the known dates when certain languages

split, and with their known geographical ranges, a computer calculated the most

likely relationships among all Indo-European languages and concluded that protoIndo-European probably originated in Anatolia 9,000 years ago.

Disputing this conclusion, skeptics argue that most Indo-European languages

are similar in their words pertaining to chariots and wagons, suggesting protoIndo-European split into daughter languages only after chariots and wagons were

invented. No archaeological evidence indicates that chariots and wagons existed

before 5,500 years ago. Furthermore, proto-Indo-European had words for "horse"

and "bee" and lent many words to proto-Uralic, the mother language of Finnish

and Hungarian. The steppes north of the Black Sea were far closer than Anatolia

to areas where proto-Uralic was spoken, and had more abundant wild horses and

bees.