Wave Propagation in 1-D Spiral geometry

In this article, we investigate the wave equation in spiral geometry and study the modes of vibrations of a one-dimensional (1-D) string in spiral shape. Here we show that the problem of wave propagation along a spiral can be reduced to Bessel differential equation and hence, very closely related to the problem of radial waves of two-dimensional (2-D) vibrating membrane in circular geometry

Possible use of self-calibration to reduce systematic uncertainties in determining distance-redshift relation via gravitational radiation from merging binaries

By observing mergers of compact objects, future gravity wave experiments would measure the luminosity distance to a large number of sources to a high precision but not their redshifts. Given the directional sensitivity of an experiment, a fraction of such sources (gold plated -- GP) can be identified optically as single objects in the direction of the source. We show that if an approximate distance-redshift relation is known then it is possible to statistically resolve those sources that have multiple galaxies in the beam. We study the feasibility of using gold plated sources to iteratively resolve the unresolved sources, obtain the self-calibrated best possible distance-redshift relation and provide an analytical expression for the accuracy achievable. We derive lower limit on the total number of sources that is needed to achieve this accuracy through self-calibration. We show that this limit depends exponentially on the beam width and give estimates for various experimental parameters representative of future gravitational wave experiments DECIGO and BBO.Comment: 6 pages, 2 figures, accepted for publication in PR

Synthesis and characterization of ultrafine hydroxyapatite (HAp) powder coating on stainless steel substrate by electrophoretic deposition.

In recent years, synthesis and characterization of ultrafine hydroxyapatite (HAp) powder coating on stainless steel substrate by electrophoretic deposition gives an active area of research due to their enhanced applicability in the medical field. This makes them very attractive as prosthetic replacements. Ultrafine HAp powder was obtained by milling elemental calcium phosphate mineral. The HAp powder was dispersed into isopropyl alcohol by ultrasonication and magnetic stirring. The HAp powder was deposited by electrophoretic deposition (EPD) using lead as anode and stainless steel substrate as cathode. Powder was coated on stainless steel substrate at a voltage of 60 volt and time was varying from 15 minutes to 1.5 hours. It was observed that HAp powder deposited at 60 volt for 45 minute gives the best coating. In another set of experiment, coating time was 45 minutes having periodic time of 10 minutes with gap of 2 minutes. It was also observed that there is lack of adherence of powder particles with the substrate. To improve adherence of particles with substrate a surfactant sodium dodecyl sulfate (SDS or NaDS) (C12H25SO4Na) was added during EPD process and subsequently sintering was performed at 8000C for 2 hours in open atmosphere. X-ray diffraction (XRD) shows the peaks of HAp after deposition. It was observed from XRD spectra that XRD patterns of HAp powder that was prepared by planetary milling and HAp powder was deposited on stainless steel substrate by EPD at 60 volts for 15 minutes. Here the some peaks of HAp are visible in the coated substrate along with peaks of stainless steel. The intensity of HAp peaks in the coated substrate is lesser than pure HAp powder. This is due to the presence of large peak of stainless steel along with HAp. It was observed from SEM analysis that HAp deposited on stainless steel substrate at 1 hour shows smooth and good adherence where as for deposition of 1.5 hours shows discontinuous and non-adherence deposition. As the time of deposition is increased there may be formation of thick layer which may generate cracks

Comparative study of maternal and perinatal outcome in pregnancies with and without umbilical cord around foetal neck

Background: Umbilical cord around neck of the foetus is called the nuchal cord. The aims and objectives are to find out the incidence of nuchal cord around foetal neck at delivery, and to compare and evaluate intrapartum and postpartum maternal and foetal outcome in those with or without nuchal cord at delivery.Methods: It is a prospective cross-sectional study conducted at tertiary care hospital for period of 12 months. Of 1380 patients, 934 patients were enrolled in present study after meeting the inclusion and exclusion criteria of which 150 patients were included in study group who delivered with nuchal cord and 784 patients in control group who delivered without nuchal cord.Results: Present study showed 18.84% incidence of nuchal cord at delivery. Duration of labour was 6.51hrs in study group and 6.15hrs in control group and the difference was statistically significant. Rest of the intrapartum and postpartum events were statistically not significant. Mean length of cord was more in patients delivered with loop of cord around foetal neck as compared to another group and it is statistically significant.Conclusions: Nuchal cord is a common finding at the time of delivery. However, it is per-se not an indication of LSCS and it only increases the operative morbidity

ROLE OF PATHYAPATHYAS IN THE ADMINISTRATION OF RASOUSHADHAS

Ayurveda is a medical system which has well developed systems of diagnosis and treatment. It is the only medical system in world, which has apparatus to deal with complete human being, which comprises of mind, body and soul. The treatment is highly personalized according to the patients physical nature, age, immunity, mind power, habit etc. A customized diet, life style, exercise, mental support, breathing and meditation techniques also form the part of the treatment. There is a section in Ayurveda called Rasasastra which describes the use of metals, minerals, and poisons with their actions to combat chronic and complicated diseases. As we all know most of the Rasa drugs are toxic. These pass through extensive processing before they are declared fit for internal use. These preparations are sustaining themselves since centuries in clinical use. A thing that does not adversely affect the body and mind is known as Pathya (wholesome) the diet and regimens opposite to these qualities are said to be Apathya (unwholesome). Many Pathyapathya ahara viharas are mentioned in the Rasa classics. The rationale behind the selection of Aharas and Viharas as Pathya (wholesome) or Apathya (unwholesome) mainly depends on the properties of drugs which are used as Pathya as well as that of drug which is used as medicine. The implied meaning is rules and regulations about diet and movements etc. to be advised by the Physician along with treatment. The medicines are ineffective unless these are followed. In the case of Pathya most probable drug interaction will be synergism and of Apathya dravyas will be antagonism. However, their improper processing, misuse, improper mode of administration may cause adverse effects in the human body. Even though the drugs are in assimilable forms, there should be suitable vehicles for their absorption. Here comes the importance of Pathyapathya while using these metallic forms. Suitable Pathya is necessary while using these Rasa drugs for proper absorption of drug, to reduce its adverse effects, to increase its bio-availability etc