2,286 research outputs found
General relativistic treatment of LISA optical links
LISA is a joint space mission of the NASA and the ESA for detecting low
frequency gravitational waves in the band Hz. In order to attain
the requisite sensitivity for LISA, the laser frequency noise must be
suppressed below the other secondary noises such as the optical path noise,
acceleration noise etc. This is achieved by combining time-delayed data for
which precise knowledge of time-delays is required. The gravitational field,
mainly that of the Sun and the motion of LISA affect the time-delays and the
optical links. Further, the effect of the gravitational field of the Earth on
the orbits of spacecraft is included. This leads to additional flexing over and
above that of the Sun. We have written a numerical code which computes the
optical links, that is, the time-delays with great accuracy
metres - more than what is required for time delay interferometry (TDI) - for
most of the orbit and with sufficient accuracy within metres for an
integrated time window of about six days, when one of the arms tends to be
tangent to the orbit. Our analysis of the optical links is fully general
relativistic and the numerical code takes into account effects such as the
Sagnac, Shapiro delay, etc.. We show that with the deemed parameters in the
design of LISA, there are symmetries inherent in the configuration of LISA and
in the physics, which may be used effectively to suppress the residual laser
noise in the modified first generation TDI. We demonstrate our results for some
important TDI variables
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
Capparis sepiaria Linn - Pharmacognostical standardization and toxicity profile with chemical compounds identification (GC-MS)
The present study was intended to evaluate the various pharmacognostical procedures in the leaves of Capparis sepiaria Linn., (Capparidaceae). The various pharmacognostical parameters were carried out as per WHO guidelines procedure i.e., bitterness, fineness, microscopical sections, loss on drying, water and alcoholic extractive values, water insoluble ash, acid soluble ash, total ash, swelling index, foaming index, heavy metal analysis, phytochemical analysis and toxicity studies (acute, subacute and chronic toxicity). The study was extended with analyzing the chemical compounds identification in the EECS (ethanolic extract of Capparis sepiaria by using GC-MS. The presence of various phytoconstituents such as glycosides, reducing sugars, flavonoids, saponins, starch and terpenoids is evidenced in EECS & AECS. The results showed that acid insoluble ash (1.70%), total ash (8.68%), water soluble ash (3.42%), water extractive (31.55%), alcohol extractive (5.06%), foaming index (105.26 Unit), loss on drying (9.84%), swelling index (4.16%), acute toxicity (nil), sub-acute toxicity (nil), chronic toxicity (nil). The study was concluded with the plant has standardized as per the World Health Organization procedures. The result of the pharmacognostical standardization of this plant serves as a reference piece and helps in future identification and authentication of this plant specimen. Might be the plant C. sepiaria has potential property by the standardization and it can be included in the normal flora of the plant kingdom.Keywords: C. sepiaria; Microscopical; Macroscopical standardization
Capparis sepiaria Linn - Pharmacognostical standardization and toxicity profile with chemical compounds identification (GC-MS)
The present study was intended to evaluate the various pharmacognostical procedures in the leaves of Capparis sepiaria Linn., (Capparidaceae). The various pharmacognostical parameters were carried out as per WHO guidelines procedure i.e., bitterness, fineness, microscopical sections, loss on drying, water and alcoholic extractive values, water insoluble ash, acid soluble ash, total ash, swelling index, foaming index, heavy metal analysis, phytochemical analysis and toxicity studies (acute, subacute and chronic toxicity). The study was extended with analyzing the chemical compounds identification in the EECS (ethanolic extract of Capparis sepiaria by using GC-MS. The presence of various phytoconstituents such as glycosides, reducing sugars, flavonoids, saponins, starch and terpenoids is evidenced in EECS & AECS. The results showed that acid insoluble ash (1.70%), total ash (8.68%), water soluble ash (3.42%), water extractive (31.55%), alcohol extractive (5.06%), foaming index (105.26 Unit), loss on drying (9.84%), swelling index (4.16%), acute toxicity (nil), sub-acute toxicity (nil), chronic toxicity (nil). The study was concluded with the plant has standardized as per the World Health Organization procedures. The result of the pharmacognostical standardization of this plant serves as a reference piece and helps in future identification and authentication of this plant specimen. Might be the plant C. sepiaria has potential property by the standardization and it can be included in the normal flora of the plant kingdom.Keywords: C. sepiaria; Microscopical; Macroscopical standardization
STUDIES ON BACTERIAL POPULATION IN INTENSIVE CARE UNIT OF THANJAVUR MEDICAL COLLEGE
In the present study the following bacterial species were isolated and identified from Intensive Care Unit / Intensive Critical Care Unit of Thanjavur Medical College Hospital (TMCH), Thanjavur. Totally five species of bacteria were isolated and identified based on colony morphology, Gram staining and biochemical studies. The identified bacteria namely Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli,Staphylococcus aureus and Serratiamarcensis spp. All the organisms were tested against antibiotic sensitivity test, the three commercially available common antibiotic discs like Ciproflaxacin, Penicillin G and Streptomycin were used all the organisms were sensitive. Thus, it promotes the treatment against the original pathogen and reduces the consumption of wide spectrum of antibiotic which in turn reduces the consumption of wide spectrum of antibiotic which in turn reduces a wide spectrum of side effects and thus save the humans from the lower extremity amputations in time
Analysis of interaction between Arbuscular Mycorrhizal fungi and their Helper bacteria by MILPA model
Many recent researches carried out the research in mycorrhizal symbiosis to improve crop growth in the agriculture but they differ in their approaches like crops and the agricultural perspectives. The study focused on the interaction of Arbuscular mycorrhizal (AM) fungi and helper bacteria, influence maize growth through milpa as a model system to analyze soil enzyme activity of acid, alkaline phosphatase and signaling molecule of phospholipids fatty acid (PLFA) profile. Bioinoculants plays an important role in plant growth like nutrient mobilization, biocontrol and prevent the plants from stress. The maize crops were treated with bio inoculants such as Azospirillum, Azotobacter, Rhizobium,Pseudomonas and AM fungi. Significant diverse effects were observed with bioinoculants in the crops compared to control crop. The number spores formed was proportional to the rate of colonization.AM fungi association in plant roots helps the plants in nutrient uptake especially phosphorus (P) from soil materials. The enzyme activities were also found to influence the growth of the plant and phospholipids fatty acid (PLFA) profile influences the interaction between bacterium and AMF. Plant and phospholipids fatty acid analysis is asensitive and accurate method in determining microbial community structures, because it depends on living cell contents of microorganisms under in situ conditions. It confirmed with gas chromatographic analysis of PLFA to determination of the structure and total biomass of microbial community in treated soil samples
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