Optical Photometry of the GRB 010222 Afterglow

The optical afterglow of GRB 010222 was observed using the recently installed 2-m telescope at the Indian Astronomical Observatory, Hanle, and the telescopes at the Vainu Bappu Observatory, Kavalur, beginning ~ 0.6 day after the detection of the event. The results based on these photometric observations combined with others reported in the literature are presented in this paper. The R band light curve shows an initial decline of intensities proportional to t^{-0.542} which steepens, after 10.3 hours, to t^{-1.263}. Following the model of collimated outflow, the early break in the light curve implies a very narrow beam angle (~ 2-3 deg). The two decay rates are consistent with the standard jet model in a uniform density ambient medium, but require a hard spectrum of electron power density with p ~ 1.5. The R band light between 14 and 17 hours since outburst departs from the power law fit by 0.1 mag and shows some evidence for fluctuations over timescales of an hour in the observer's frame. Such deviations are expected due to density inhomogeneities if the ambient medium is similar to the local interstellar medium. GRB 010222 is thus an example of a highly collimated outflow with a hard spectrum of electron energy distribution in normal interstellar environment.Comment: 15 pages, Latex, including 2 postscript figures, to appear in the Bull. astro. Soc. India, September 2001 issu

Screening Fetal Echocardiography in the First Trimester: A study from a Tertiary Unit in a Teaching Hospital

INTRODUCTION: The most common birth defect is considered as congenital heart disease, impacting 3-8 per 1000 live births; An estimate of approximately 1% will show sonographic evidence of a cardiac anomaly on a screening ultrasound performed during second trimester of pregnancy. The impact of congenital heart disease is enormous on pregnancy outcome; Intrauterine demise complicates 20-30% of fetuse with known cardiac defects, and for certain lesions, neonatal death occurs in 40-60% of cases, with long term survival rates ranging from 15-40%. To identify the cardiac defect prenatally timely can offer the families the opportunity to receive appropriate counselling regarding the anticipated fetal and neonatal outcome ; Also the decision regarding the continuation of pregnancy can be decided ; adding to it, prenatal diagnosis allows for transfer of care to a facility with expert neonatology, pediatric cardiology, and pediatric cardiac surgery services, a resource that can have a major impact on the outcome of affected neonates. AIM OF THE STUDY: To access the technical feasibility of screening of first trimester echocardiography in all antenatal patients of gestational between 11 weeks - 13 weeks + 6 days, attending OG- OPD in PSG Hospital. OBJECTIVE: Using a trans-abdominal approach after determination of fetal position and visceral situs, following fetal cardiac views are visualized and allotted points to access feasibility. • Four chamber view -2D and color Doppler, • Three vessel view-2D and color Doppler (V sign, • Tricuspid valve flow, • Ductus venosus flow. STUDY DESIGN: Cross sectional study. STUDY POPULATION: All Antenatal mother of gestational age between 11weeks-13 weeks + 6 days of gestational age attending OG-OPD in PSG Hospital. SAMPLE SIZE AND ITS JUSTIFICATION: 500 (4PQ/d2). INCLUSION CRITERIA: All Antenatal mother of gestational age between 11weeks-13 weeks + 6 days of gestational age attending OG-OPD in PSG Hospital. EXCLUSION CRITERIA: All Antenatal mother of gestational age between 11weeks-13 weeks + 6 days of gestational age bleeding per vaginum and abdominal pain. MATERIALS AND METHODS: All 500 cases underwent first trimester basic heart examination by a single trained operator by both trans abdominally and trans vaginally .Maternal BMI was noted. Following planes four chamber view, three vessel trachea view, tricuspid flow, ductus venosus flow were visualized. A specific criteria has been developed, a SCORING SYSTEM, for the following 4- chamber view, 3 vessel trachea view, tricuspid flow, ductus venosus flow. These criteria has been identified to reflect the quality of the information in the images, and they are used by the expert assessor to establish scores for the image. Average time taken for the same calculated along with the number of sittings. The scores of 4 chamber view, 3 vessel trachea view, tricuspid flow and ductus venosus were analysed to access the relationship to maternal body mass index (25); fetal CRL category (45-54mm, 55-64mm, 65-74mm, 75-84mm), parity, mode of conception, maternal age, fetal heart examination length, number of sittings, maternal diabetes. RESULT: In this flash study, a single trained observer, performed a total of 500 first trimester ultra sound examination. The median maternal age of the study population is 26 years. The mean body mass index is 23.1%. The mean gestational age is 12 weeks. Our success rate of four chamber view is 89.6 % and our success rate of three vessel trachea view 90.2 % ; Also the combined success rate of both 4 CV and 3 VT view is 83.8%. Among our 500 cases, 10% (n=50) of 4CV images and 8% of 3 VT views were deemed sub-optimal or atypical. In the 432 cases, trans abdominal examination was done, whereas in 68 cases an additional trans vaginal ultrasound was performed, as only trans abdominal was deemed inadequate. Our present study also furnished with almost comparable result of mean duration of 15 minutes in case of trans abdominal examination and a mean duration of 25 minutes in case of trans vaginal examination. CONCLUSION: It is therefore possible for a trained operator to perform simplified fetal echocardiography during the routine first trimester ultrasound examination in a low risk population. Hence, it is very important to encourage development of the concept of simplified first trimester echocardiographic examination in a low risk population. Also, in most cases reassurance can be given to the parents by performing this basic heart examination. Adding to it, potential problems can be identified and clarified as early as possible in the second trimester

Computing the multifractal spectrum from time series: An algorithmic approach

We show that the existing methods for computing the f(\alpha) spectrum from a time series can be improved by using a new algorithmic scheme. The scheme relies on the basic idea that the smooth convex profile of a typical f(\alpha) spectrum can be fitted with an analytic function involving a set of four independent parameters. While the standard existing schemes [16, 18] generally compute only an incomplete f(\alpha) spectrum (usually the top portion), we show that this can be overcome by an algorithmic approach which is automated to compute the Dq and f(\alpha) spectrum from a time series for any embedding dimension. The scheme is first tested with the logistic attractor with known f(\alpha) curve and subsequently applied to higher dimensional cases. We also show that the scheme can be effectively adapted for analysing practcal time series involving noise, with examples from two widely different real world systems. Moreover, some preliminary results indicating that the set of four independant parameters may be used as diagnostic measures is also included.Comment: 10 pages, 16 figures, submitted to CHAO

Comparative study of efficacy and safety of vaginal misoprostol versus oral misoprostol in induction of labour when used in equal doses

Background: It was a randomized controlled prospective study. A large number of women in their advanced pregnancies often need labour induction for various reasons. This study aims to evaluate a safe, effective and inexpensive mode of medical induction. The purpose of the study is to evaluate the safety and efficacy of vaginal misoprostol versus oral misoprostol in induction of labour when used in equal doses.Methods: Two hundred patients were included in the study. They were divided into two groups of 100 patients each. One group i.e. Group A received vaginal misoprostol while the other group i.e. Group B received oral misoprostol. The dosage was 50μg every 6th hourly maximum of four doses. The progress of labour in both groups was charted on a partogram. The outcome of pregnancy, maternal and foetal outcomes were statistically analysed.Results: When compared with respect to age, height, gestational age, indication for induction, there was no difference in either of the groups. The numbers of doses of misoprostol for successful outcome of labour in the vaginal group i.e. 2.25±0.53 was lesser than the dosage needed in the oral group i.e. 2.71±0.60 (P value M 0.0001). which is highly significant. The induction-delivery interval was also less in the vaginal group compared to the oral group. (12.90±2.40 hours versus 15±75 hours). Only 13 women in the vaginal group needed acceleration with oxytocin in contrast to 17 women in the oral group. The need for caesarean section in women induced with vaginal misoprostol was 12 women in comparison to oral group which was 32 women. No statistically significant difference was seen in neonatal outcome in either of the groups.Conclusions: When given in equal doses the vaginal administration of misoprostol is more effective in successful induction of labour when compared to oral misoprostol

Pregnancy outcome in low risk pregnancy with decreased amniotic fluid index

Background: To evaluate whether oligohydramnios (AFI≤5) has any significance in the outcome of low risk pregnancies. Normal amniotic fluid index in pregnancy is one of the indicators of fetal well-being.  In a term pregnancy, oligohydramnios, a condition associated with AFI≤5, could be a sign of placental insufficiency. An association of low AFI with complications like pregnancy induced hypertension, consistently leads to poor fetal outcome. A need to deliver the fetus by cesarean section often arises. Occasionally one comes across a full-term pregnancy with AFI ≤5 with no known high risk factors; this could lead to increased cesarean section rates. Thus, it becomes necessary to evaluate if AFI ≤5 in the absence of other risk factors has any significance on obstetric outcome.Methods: Prospective case controlled study was done. Fifty women with term pregnancies and (AFI≤5) cm not associated with any other high risk factors were enrolled for the study. They were matched with fifty controls with normal AFI.Results: Except for a slight increase in variable deceleration in the study group, no differences were noted with fetal heart rate recordings in NST.  Decreased AFI was not associated with increased cesarean section rates, instrumental deliveries or meconium stained amniotic fluid. Severe asphyxia, NICU admission or perinatal mortality was not noted in either group.Conclusions: When a low risk pregnancy is associated with Oligohydramnios (AFI≤5), it does not have any deleterious effect on labor outcome or perinatal outcome

Safety evaluation of Sapindus laurifolius leaf extract in Wistar rats

Objectives:The present work was aimed to study the phytochemical composition of the Sapindus laurifolius leaves andtoxicological effect of the Sapindus laurifolius leaf extract in a systematic way using Wistar albino rats as a model animal.Materials and Methods :The identification of phytoconstituents present in the leaf extract was performed using Highperformance thin layer chromatography (HPTLC). In toxicity studies, the acute oral toxicity study was conducted as per theguidelines of Organization for Economic Co-operation and Development (OECD 423 Acute Toxic Class Method) for testingof chemicals. In repeated dose 28-day oral toxicity study (OECD 407), methanolic leaf extract administered at the dose of 50,200 and 800 mg/kg BWand limit dose of 1000 mg/kg BW.Results: Saponins, flavanoids, glycosides and bitter principles were the major phytoconstituents identified. In acute toxicitystudy, the LD cut-off values were found to be more than 2g/kg in leaf extract. In repeated dose 28-day oral toxicity, significant 50(P<0.05) increase in AST, ALT, BUN and creatinine, significant (P<0.05) increase in total protein was noticed. Thehistopathological changes confined to liver, kidney and intestine, revealed mild to moderate hepatotoxicity, severenephrotoxicity and increased goblet cell activity. The changes were found to correlate with increased dose of leaf extract.Conclusion:The phytochemical analysis of Sapindus laurifolius revealed the presence of saponins, glycosides, flavonoidsand bitter principles.The acute oral toxicity study of S. laurifolius methanolic leaf extract in rats resulted in no toxicity even atthe highest dose, but in repeated 28-day oral toxicity study revealed mild to moderate hepatotoxicity, severe nephrotoxicityand intestinal damage

Signcryption with Proxy Re-encryption

Confidentiality and authenticity are two of the most fundamental problems in cryptography. Many applications require both confidentiality and authenticity, and hence an efficient way to get both together was very desirable. In 1997, Zheng proposed the notion of ``signcryption\u27\u27, a single primitive which provides both confidentiality and authenticity in a way that\u27s more efficient than signing and encrypting separately. Proxy re-encryption is a primitive that allows a semi-trusted entity called the ``proxy\u27\u27 to convert ciphertexts addressed to a ``delegator\u27\u27 to those that can be decrypted by a ``delegatee\u27\u27, by using some special information given by the delegator, called the ``rekey\u27\u27. In this work, we propose the notion of signcryption with proxy re-encryption (SCPRE), and motivate the same. We define security models for SCPRE, and also propose a concrete unidirectional, non-interactive identity-based SCPRE construction. We also provide complete proofs of security for the scheme in the security models defined. We finally provide directions for further research in this area

Interrelationships between nematicity, antiferromagnetic spin fluctuations and superconductivity: Role of hotspots in FeSe1−x_{1-x}Sx_{x} revealed by high pressure 77^{77}Se NMR study

The sulfur-substituted FeSe, FeSe$_{1-x}$S$_{x}$, is one of the unique systems that provides an independent tunability of nematicity, antiferromagnetism and superconductivity under pressure ($p$). Recently Rana et al. [Phys. Rev. B 101, 180503(R) (2020)] reported, from $^{77}$Se nuclear magnetic resonance (NMR) measurements on FeSe$_{0.91}$S$_{0.09}$ under pressure, that there exists a clear role of nematicity on the relationship between antiferromagnetic (AFM) spin fluctuations and superconducting transition temperature ($T_{\rm c}$) where the AFM spin fluctuations are more effective in enhancing $T_{\rm c}$ in the absence of nematicity than with nematicity. Motivated by the work, we carried out $^{77}$Se NMR measurements on FeSe$_{1-x}$S$_{x}$ with $x$= 0.15 and 0.29 under pressure up to 2.10 GPa to investigate the relationship in a wide range of $x$ in the FeSe$_{1-x}$S$_x$ system. Based on the new results together with the previously reported data for $x$=0 [P. Wiecki et al., Phys. Rev. B 96, 180502(R) (2017)] and 0.09 [K. Rana et al. Phys. Rev. B 101, 180503(R) (2020)], we established a $p$ - $x$ - temperature ($T$) phase diagram exhibiting the evolution of AFM spin fluctuations. From the systematic analysis of the NMR data, we found that the superconducting (SC) state in nematic state arises from a non Fermi liquid state with strong stripe-type AFM spin fluctuations while the SC state without nematicity comes from a Fermi liquid state with mild stripe-type AFM spin fluctuations. Furthermore, we show that the previously reported impact of nematicity on the relationship between AFM fluctuations and superconductivity holds throughout the wide range of $x$ from $x$ = 0 to 0.29 in FeSe$_{1-x}$S$_{x}$ under pressure. We discuss the origin of the role of nematicity in terms of the different numbers of hotspots on Fermi surfaces with and without nematicity.Comment: 11 pages, 9 figures, accepted for publication in Phys. Rev.