Simultaneous X-ray and optical observations of thermonuclear bursts in the LMXB EXO 0748-676

We report the detection of a large number of optical bursts in the Low Mass X-ray Binary (LMXB) EXO 0748-676 simultaneous with the thermonuclear X-ray bursts. The X-ray and the optical bursts are detected in a long observation of this source with the XMM-Newton observatory. This has increased the number of thermonuclear X-ray bursts in the LMXBs with simultaneous optical detection by several factors. The optical bursts are found to have a linear rise followed by a slow, somewhat exponential decay. Most of the optical bursts have longer rise and decay timescale compared to the corresponding X-ray bursts. We have determined the X-ray and optical excess photon counts in the bursts that allow us to look at the optical to X-ray burst fluence ratio for each burst and the ratio as a function of the X-ray burst intensity and as a function of the orbital phase. The delay between the onset of the X-ray bursts and the onset of the optical bursts have also been measured and is found to have an average value of 3.25 seconds. We do not find any convincing evidence of orbital phase dependence of the following parameters: X-ray to optical delay, rise time of the optical bursts, and optical to X-ray burst intensity ratio as would be expected if the optical bursts were produced by reprocessing from the surface of the secondary star that is facing the compact star. On the other hand, if the optical bursts are produced by reprocessing of the X-rays in the accretion disk, the onset of the bursts is not expected to have a sharp, linear shape as is observed in a few of the bursts in EXO 0748-676. We emphasise the fact that simultaneous optical observations of the X-ray bursts in multiple wavelength bands will enable further detailed investigations of the reprocessing phenomena, including any non-linear effect of the X-ray irradiation.Comment: 12 pares, 5 figures (Submitted to the Bulletin of the Astronomical Society of India

Intranasal scopolamine preparation and method

A new method and preparation for intranasal delivery of scopolamine provides a safe and effective treatment for motion sickness and other conditions requiring anticholinergic therapy. The preparation can be in the form of aqueous nasal drops, mist spray, gel or oinment. Intranasal delivery of scopolamine has similar bioavailability and effect of intravenous delivery and is far superior to oral dosage. Scopolamine is prepared in a buffered saline solution at the desired dosage rate for effective anticholinergic response

Pharmacokinetics and Pharmacodynamics in Space

The Pharmacokinetics and Pharmacodynamics Panel met on 29-30 Aug. 1988 at the Lunar and Planetary Institute in Houston, Texas to discuss pharmacokinetic and pharmacodynamic implications of space flight and make recommendations for operational and research strategies. Based on the knowledge available on the physiological changes that occur during space flight, the dependence of pharmacokinetics on physiological factors, and the therapeutic requirements for future space missions, the panel made several recommendations for research. It was suggested that using medications available with a large (wide) therapeutic window will avoid unforeseen therapeutic consequences during flight. The sequence for conducting research was outlined as follows: (1) identify ground-based simulation models (e.g., antiorthostatic bed rest) for conducting pharmacokinetic and pharmacodynamic research; (2) estimate parametric changes in these models using pharmacologic agents that have different pharmacokinetic characteristics and a narrow therapeutic index; (3) verify these findings during flight; and (4) develop and identify appropriate and effective drug delivery systems, dosage forms, and regimens. The panel recommended gaining a thorough understanding of the pharmacokinetic deviations of medications that have a narrow therapeutic index (e.g. cardiovascular drugs and sedative hypnotics) in order to ensure safe and effective treatment during flight with these agents. It was also suggested that basic information on physiological factors such as organ blood flow, protein composition and binding, tissue distribution, and metabolism by hepatic enzymes must be accumulated by conducting ground-based animal and human studies using models of weightlessness. This information will be useful to construct and identify physiologically based pharmacokinetic models that can provide valuable information on the pharmacodynamic consequences of space flight and aid in identifying appropriate therapeutic regimens

The MVA Priority Approximation

A Mean Value Analysis (MVA) approximation is presented for computing the average performance measures of closed-, open-, and mixed-type multiclass queuing networks containing Preemptive Resume (PR) and nonpreemptive Head-Of-Line (HOL) priority service centers. The approximation has essentially the same storage and computational requirements as MVA, thus allowing computationally efficient solutions of large priority queuing networks. The accuracy of the MVA approximation is systematically investigated and presented. It is shown that the approximation can compute the average performance measures of priority networks to within an accuracy of 5 percent for a large range of network parameter values. Accuracy of the method is shown to be superior to that of Sevcik's shadow approximation

A deep survey of the low-surface-brightness radio sky

We have made a radio survey--the Australia Telescope Low Brightness Survey (ATLBS)--of 8.4 square degrees sky area, using the Australia Telescope Compact Array in the 20-cm band, in an observing mode designed to provide wide-field images with exceptional sensitivity in surface brightness, and thereby explore a new parameter space in radio source populations. The goals of this survey are to quantify the distribution in angular sizes, particularly at weak surface brightness levels: this has implications for the confusion in deep surveys with the SKA. The survey is expected to lead to a census of the radio emission associated with low-power radio galaxies at redshifts 1-3, without any missing extended emission, and hence a study of the cosmic evolution of low-power radio galaxies to higher redshift and a comprehensive study of the AGN feedback during the intense black hole growth phase during this redshift range.Comment: 5 pages, includes 2 figures and 1 table. To appear in the proceedings of "From Planets to Dark energy: the modern radio universe" in the online journal Proceedings of Science - Po

Role of neutrophil-lymphocyte ratio in determining the outcomes of preterm premature rupture of membranes

Background: Premature Rupture of Membranes (PROM) is a significant obstetric problem. Evaluation of neutorphil-lymphocyte ratio (NLR) is expected to throw light on the potential scope of early prediction of PPROM. With this background, the present study was carried out to compare the NLR among preterm PROM and healthy controls to evaluate the predictive role of NLR and platelet-lymphocyte ratio (PLR).Methods: This case control study was carried out among 101 pregnant women 44 pregnant women diagnosed with Preterm PROM and 55 term gestation matched healthy controls. Laboratory parameters (including complete blood count were measured. PLR was calculated as the number of platelets divided by the lymphocyte count, and NLR was calculated by dividing the neutrophil Count by the lymphocyte count, both of which were obtained from the same blood samples.Results: All the inflammatory markers including total count, neutrophil count, NLR and PLR ratios were elevated among PPROM group compared to the controls. The observed differences in the mean levels of these parameters were statistically significant (p<0.05).Conclusions: It may be considered that monitoring of NLR during second and early third trimesters as a routine practice among high risk mothers can significantly help in early prediction of PPROM and help in minimizing adverse maternal and neonatal outcomes