10,335 research outputs found
Teaching of Critical Analysis of Drug Advertisements to Medical Students
Background: Medical practitioners utilize drug promotional materials from pharmaceutical companies as a major source of information especially in developing countries. These promotional materials can be highly informative as long as they are critically appraised but when they are accepted without question, they lead to irrational prescribing. Aim: To sensitize the students regarding WHO criteria for medicinal drug promotion and to determine the impact of teaching critical appraisal of medicinal drug promotion to medical students. Design: The medical students of second year were given a pre test questionnaire to identify the violations in generic labeling, pharmacological information, claims, relevance and references cited in the drug advertisements. Later they were sensitized about the WHO criteria for medicinal drug promotion and how to critically appraise a drug advertisement. This was followed by a post test questionnaire with the same drug advertisement. Result: The number of students answering the post test correctly was significantly (p<0.05) more than that of pre test. Conclusion: Education of medical students regarding critical analysis of drug advertisements should be a part of the medical curriculum
Time Delay Interferometry for LISA with one arm dysfunctional
In order to attain the requisite sensitivity for LISA - a joint space mission
of the ESA and NASA- the laser frequency noise must be suppressed below the
secondary noises such as the optical path noise, acceleration noise etc. By
combining six appropriately time-delayed data streams containing fractional
Doppler shifts - a technique called time delay interferometry (TDI) - the laser
frequency noise may be adequately suppressed. We consider the general model of
LISA where the armlengths vary with time, so that second generation TDI are
relevant. However, we must envisage the possibility, that not all the optical
links of LISA will be operating at all times, and therefore, we here consider
the case of LISA operating with two arms only. As shown earlier in the
literature, obtaining even approximate solutions of TDI to the general problem
is very difficult. Since here only four optical links are relevant, the
algebraic problem simplifies considerably. We are then able to exhibit a large
number of solutions (from mathematical point of view an infinite number) and
further present an algorithm to generate these solutions
Optimising the directional sensitivity of LISA
It was shown in a previous work that the data combinations canceling laser
frequency noise constitute a module - the module of syzygies. The cancellation
of laser frequency noise is crucial for obtaining the requisite sensitivity for
LISA. In this work we show how the sensitivity of LISA can be optimised for a
monochromatic source - a compact binary - whose direction is known, by using
appropriate data combinations in the module. A stationary source in the
barycentric frame appears to move in the LISA frame and our strategy consists
of "coherently tracking" the source by appropriately "switching" the data
combinations so that they remain optimal at all times. Assuming that the
polarisation of the source is not known, we average the signal over the
polarisations. We find that the best statistic is the `network' statistic, in
which case LISA can be construed of as two independent detectors. We compare
our results with the Michelson combination, which has been used for obtaining
the standard sensitivity curve for LISA, and with the observable obtained by
optimally switching the three Michelson combinations. We find that for sources
lying in the ecliptic plane the improvement in SNR increases from 34% at low
frequencies to nearly 90% at around 20 mHz. Finally we present the
signal-to-noise ratios for some known binaries in our galaxy. We also show
that, if at low frequencies SNRs of both polarisations can be measured, the
inclination angle of the plane of the orbit of the binary can be estimated.Comment: 16 pages, 8 figures, submitted to Phys Rev
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