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rohitshetty985 Says
I am also interested in knowing strategies for the RC passages. Please share

Google RC strategies for the GMAT and you should get the relevant links
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There are so many rules, that one can always argue !!

But a better explanation:
If other hallucinogens (i.e., drugs that cause hallucinations) are able
to produce hallucinations without inhibiting serotonin, then the central premise of
Jacobs' hypothesis--that dreams and hallucinations function via a similar brain
mechanism involving the levels of serotonin and norepinephrine--would not hold.

Yeah the Correct Ans is D

Can you guys please share strategies for RC passages - generally I read whole passage trying to remember, making myself entrapped in subject of passage, read the question, then options if cant conclude on one, eliminate intermittently referring to passage but is it the best way? It could be time consuming...whats the best way?

ISBCo2014 spreadsheet - https://docs.google.com/spreadsheet/ccc?key=0AkGkc0yWHIvAdE9DZ2UwbDB4TlIxZkpnZnZITUpEemc
Scientific advances in the latter half of the twentieth century
have allowed researchers to study the chemical activities
taking place in the human brain during the sleep cycle in
more detail. In the 1970s, Jacobs employed these
advances to postulate that dreams and hallucinations share
a common neurochemical mechanism with respect to the
neurotransmitters serotonin and norepinephrine that
accounts for the observable similarities between the two
states of mind. To test the theory, researchers attempted
to elucidate the role of these transmitters in the normal
sleep cycle and the effect of hallucinogenic drugs on them.
Although scientists still have much to discover about the
chemical complexities of the brain, serotonin appears
important for managing sleep, mood, and appetite, among
other important functions, while neurons release
norepinephrine to facilitate alertness and mental focus.
Both are discharged in high quantities only during waking
states. At the onset of sleep, the activity levels of neurons
that release both the neurotransmitters drop, allowing
the brain first to enter the four non-rapid eye movement
(Non-REM) stages of sleep. When the brain is ready to
enter the fifth stage, REM, which is associated with
dreaming, the levels of these two chemicals drop virtually
to zero. The Jacobs hypothesis held that the absence of
norepinephrine was required to enable the brain to remain
asleep, while the absence of serotonin was necessary to
allow dreaming to occur.
Lysergic acid diethylamide, or LSD, is a semi-synthetic
psychedelic drug which causes significant alteration of
the senses, memories and awareness; at doses higher
than 20 micrograms, it can have a hallucinogenic effect.
LSD mimics serotonin well enough to be able to bind at
most of the neurotransmitters receptor sites, largely
inhibiting normal transmission. In addition, the drug causes
the locus ceruleus, a cluster of neurons containing
norepinephrine, to greatly accelerate activity. If the drug
stimulates norepinephrine, thereby precluding sleep, and
inhibits serotonin, which Jacobs had postulated was a
necessary condition for dreaming, then the resulting
hallucinations could merely be dreaming while awake.
The research thus far is promising but inconclusive; future
scientific advances should allow this theory to be tested
more rigorously.


1. Which of the following, if true, would most undermine
the central premise of the Jacobs hypothesis?
of serotonin.

role in regulating sleep.

norepinephrine in the brain is a significant factor in
enabling the brain to sleep.

LSD do not inhibit serotonin.

process of dreaming as the fifth stage.



D, IMO

Explanation = Jacob hypothesis "the absence of
norepinephrine was required to enable the brain to remain
asleep, while the absence of serotonin was necessary to
allow dreaming to occur."

If "Some semi-synthetic hallucinogenic drugs other than
LSD do not inhibit serotonin", and still person goes in a state of hallucination (that is dreaming while not falling asleep) then serotonin is still present yet a person is dreaming, contradicting with above hypothesis
ISBCo2014 spreadsheet - https://docs.google.com/spreadsheet/ccc?key=0AkGkc0yWHIvAdE9DZ2UwbDB4TlIxZkpnZnZITUpEemc

Scientific advances in the latter half of the twentieth century
have allowed researchers to study the chemical activities
taking place in the human brain during the sleep cycle in
more detail. In the 1970s, Jacobs employed these
advances to postulate that dreams and hallucinations share
a common neurochemical mechanism with respect to the
neurotransmitters serotonin and norepinephrine that
accounts for the observable similarities between the two
states of mind. To test the theory, researchers attempted
to elucidate the role of these transmitters in the normal
sleep cycle and the effect of hallucinogenic drugs on them.
Although scientists still have much to discover about the
chemical complexities of the brain, serotonin appears
important for managing sleep, mood, and appetite, among
other important functions, while neurons release
norepinephrine to facilitate alertness and mental focus.
Both are discharged in high quantities only during waking
states. At the onset of sleep, the activity levels of neurons
that release both the neurotransmitters drop, allowing
the brain first to enter the four non-rapid eye movement
(Non-REM) stages of sleep. When the brain is ready to
enter the fifth stage, REM, which is associated with
dreaming, the levels of these two chemicals drop virtually
to zero. The Jacobs hypothesis held that the absence of
norepinephrine was required to enable the brain to remain
asleep, while the absence of serotonin was necessary to
allow dreaming to occur.
Lysergic acid diethylamide, or LSD, is a semi-synthetic
psychedelic drug which causes significant alteration of
the senses, memories and awareness; at doses higher
than 20 micrograms, it can have a hallucinogenic effect.
LSD mimics serotonin well enough to be able to bind at
most of the neurotransmitter's receptor sites, largely
inhibiting normal transmission. In addition, the drug causes
the locus ceruleus, a cluster of neurons containing
norepinephrine, to greatly accelerate activity. If the drug
stimulates norepinephrine, thereby precluding sleep, and
inhibits serotonin, which Jacobs had postulated was a
necessary condition for dreaming, then the resulting
hallucinations could merely be "dreaming while awake."
The research thus far is promising but inconclusive; future
scientific advances should allow this theory to be tested
more rigorously.


1. Which of the following, if true, would most undermine
the central premise of the Jacobs hypothesis?
of serotonin.

role in regulating sleep.

norepinephrine in the brain is a significant factor in
enabling the brain to sleep.

LSD do not inhibit serotonin.

process of dreaming as the fifth stage.

B is a good trap answer. Notice that the passage discusses "filtered light." This doesn't make the answer choice correct simply because it mentions filter. Analyzing (B) more carefully, we only have components being sorted. The way in which they are being sorted doesn't create a certain effect, the way that the twisting of the pixels corresponded to certain colors.

Option D:
Here the outline (or shape) of the characters corresponds to the shadow cast on the wall. Change the outline and the shape will change. Much as changing how the pixel is twisted will change the color on screen. The Answer.
(D) is by far the best answer as it is the only one that present us with a scenario in which the shape of one thing corresponds to the shape of another (outlines in paper correspond the shape of the shadow on the wall).

Can Any one Help me with This!!!

LCDs apply thin-film transistors (TFTs) of amorphous or
polycrystalline silicon sandwiched between two glass
plates. The TFTs supply voltage to liquid-crystal-filled cells,
or pixels, between the sheets of glass. When hit with an
electric charge, the liquid crystals untwist to an exact
degree to filter white light generated by a lamp. This
filtered light shines directly on the viewing screen or, in
the case of projection televisions, is projected through a
small chip that acts as a lens. LCDs that are capable of
producing color images, such as in televisions and
computers, reproduce colors through a process of
subtraction, blocking out particular color wavelengths from
the spectrum of white light until only the desired color
remains. It is the variation of the intensity of light permitted
to pass through the matrix of liquid crystals that enables
LCD displays to present images full of gradations of
different colors.

What is the correct ans for the following question

1. The process through which an LCD monitor displays
different colors is most closely analogous to
-stream of grains of sand fall into the lower portion
-of a mixture according to size
-performances within are muted to those outside
-characters cut out such that a lamp in front of the
paper casts shadows in the shapes of the characters
-while an air conditioning system cools the interior of
the building


Hi boss, how is answer D any explanation? \
ISBCo2014 spreadsheet - https://docs.google.com/spreadsheet/ccc?key=0AkGkc0yWHIvAdE9DZ2UwbDB4TlIxZkpnZnZITUpEemc

Can Any one Help me with This!!!

LCDs apply thin-film transistors (TFTs) of amorphous or
polycrystalline silicon sandwiched between two glass
plates. The TFTs supply voltage to liquid-crystal-filled cells,
or pixels, between the sheets of glass. When hit with an
electric charge, the liquid crystals untwist to an exact
degree to filter white light generated by a lamp. This
filtered light shines directly on the viewing screen or, in
the case of projection televisions, is projected through a
small chip that acts as a lens. LCDs that are capable of
producing color images, such as in televisions and
computers, reproduce colors through a process of
subtraction, blocking out particular color wavelengths from
the spectrum of white light until only the desired color
remains. It is the variation of the intensity of light permitted
to pass through the matrix of liquid crystals that enables
LCD displays to present images full of gradations of
different colors.

What is the correct ans for the following question

1. The process through which an LCD monitor displays
different colors is most closely analogous to
-stream of grains of sand fall into the lower portion
-of a mixture according to size
-performances within are muted to those outside
-characters cut out such that a lamp in front of the
paper casts shadows in the shapes of the characters
-while an air conditioning system cools the interior of
the building

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