How Common Are Magnetars? The Consequences of Magnetic-Field Decay

Ultramagnetized neutron stars or magnetars have been invoked to explain several astrophysical phenomena. We examine how the magnetic field of a magnetar will decay over time and how this decay affects the cooling of the object. We find that for sufficiently strong nascent fields, field decay alters the cooling evolution significantly relative to similarly magnetized neutron stars with constant fields. As a result, old magnetars can be expected to be bright in the soft X-ray band. The soft X-ray source RXJ~0720.4$-$3125 may well be the nearest such old magnetar.Comment: 7 pages, 1 figure, accepted for publication in Ap. J. Letter

Analysis of the Early-time Optical Spectra of SN 2011fe in M101

The nearby Type Ia supernova (SN Ia) SN 2011fe in M101 (cz = 241 km s^(–1)) provides a unique opportunity to study the early evolution of a "normal" SN Ia, its compositional structure, and its elusive progenitor system. We present 18 high signal-to-noise spectra of SN 2011fe during its first month beginning 1.2 days post-explosion and with an average cadence of 1.8 days. This gives a clear picture of how various line-forming species are distributed within the outer layers of the ejecta, including that of unburned material (C+O). We follow the evolution of C II absorption features until they diminish near maximum light, showing overlapping regions of burned and unburned material between ejection velocities of 10,000 and 16,000 km s^(–1). This supports the notion that incomplete burning, in addition to progenitor scenarios, is a relevant source of spectroscopic diversity among SNe Ia. The observed evolution of the highly Doppler-shifted O I λ7774 absorption features detected within 5 days post-explosion indicates the presence of O I with expansion velocities from 11,500 to 21,000 km s^(–1). The fact that some O I is present above C II suggests that SN 2011fe may have had an appreciable amount of unburned oxygen within the outer layers of the ejecta

Effect of Plant Growth Regulators on Growth and Yield of Daisy (Aster amellus L.) Cv. Dwarf Pink

An experiment was carried out to improve plant stature in daisy (Aster amellus L.) cv. Dwarf Pink using various growth regulators. Among the various growth promoters and their combinations tested, gibberellic acid (150ppm) and brassinosteroid (0.5ppm) application produced maximum vegetative growth, spike yield and vase-life. It is concluded that a combination of gibberellic acid (150ppm) and BR (0.5ppm) is helpful improving growth and quality in daisy cv. Dwarf Pink

Evidence for a quantum phase transition in the electron-doped cuprate Pr2-xCexCuO4+d from Hall and resistivity measurements

The doping and temperature dependence of the Hall coefficient, RH, and ab-plane resistivity in the normal state down to 350mK is reported for oriented films of the electron-doped high-Tc superconductor Pr2-xCexCuO4+d. The doping dependence of b (r=r0+AT^b) and R_sub_H (at 350 mK) suggest a quantum phase transition at a critical doping near x=0.165.Comment: 11 pages 4 figures Phys. Rev. Lett. 92, 167001 (2004

Control of superluminal transit through a heterogeneous medium

We consider pulse propagation through a two component composite medium (metal inclusions in a dielectric host) with or without cavity mirrors. We show that a very thin slab of such a medium, under conditions of localized plasmon resonance, can lead to significant superluminality with detectable levels of transmitted pulse. A cavity containing the heterogeneous medium is shown to lead to subluminal-to-superluminal transmission depending on the volume fraction of the metal inclusions. The predictions of phase time calculations are verified by explicit calculations of the transmitted pulse shapes. We also demonstrate the independence of the phase time on system width and the volume fraction under specific conditions.Comment: 21 Pages,5 Figures (Published in Journal of Modern Optics

Strong near-infrared carbon in the Type Ia supernova iPTF13ebh

We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C i lines, and the C iλ1.0693 μm line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C ii counterparts were found, even though the optical spectroscopic time series began early and is densely cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C i compared to the weaker optical C ii appears to be general in SNe Ia. iPTF13ebh is a fast decliner with Δm15(B) = 1.79 ± 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categorized as a “transitional” event, on the fast-declining end of normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh shows NIR spectroscopic properties that are distinct from both the normal and subluminous/91bg-like classes, bridging the observed characteristics of the two classes. These NIR observations suggest that composition and density of the inner core are similar to that of 91bg-like events, and that it has a deep-reaching carbon burning layer that is not observed in more slowly declining SNe Ia. There is also a substantial difference between the explosion times inferred from the early-time light curve and the velocity evolution of the Si iiλ0.6355 μm line, implying a long dark phase of ~4 days

BIOANALYTICAL METHOD DEVELOPMENT FOR ESTIMATION OF DEFERASIROX IN HUMAN PLASMA

Objective: A rapid and selective high performance liquid chromatography (HPLC) method for estimation of Deferasirox in Human plasma was developed and validated.Methods: Analyte was recovered by protein precipitation technique and subsequently separated on C18 column (150x4.5 mm, 5µ) by using acetonitrile: phosphate buffer pH 3.0(60:40) as mobile phase at a flow rate of 1.0 ml/min at 248 nm.Results: The calibration curve was linear over the concentration range 0.4-4.8 µg/ml in human plasma. Within-batch and between-batch precision were<15% (at LLOQ<20%) and accuracy was all within 15%. (at LLOQ<20%).Conclusion: The developed and validated HPLC method was specific, sensitive and reproducible which can be used for routine drug analysis and bioanalysis.Â

Self-organizing maps: a tool to ascertain taxonomic relatedness based on features derived from 16S rDNA sequence

Exploitation of microbial wealth, of which almost 95% or more is still unexplored, is a growing need. The taxonomic placements of a new isolate based on phenotypic characteristics are now being supported by information preserved in the 16S rRNA gene. However, the analysis of 16S rDNA sequences retrieved from metagenome, by the available bioinformatics tools, is subject to limitations. In this study, the occurrences of nucleotide features in 16S rDNA sequences have been used to ascertain the taxonomic placement of organisms. The tetra- and penta-nucleotide features were extracted from the training data set of the 16S rDNA sequence, and was subjected to an artificial neural network (ANN) based tool known as self-organizing map (SOM), which helped in visualization of unsupervised classification. For selection of significant features, principal component analysis (PCA) or curvilinear component analysis (CCA) was applied. The SOM along with these techniques could discriminate the sample sequences with more than 90% accuracy, highlighting the relevance of features. To ascertain the confidence level in the developed classification approach, the test data set was specifically evaluated for Thiobacillus, with Acidiphilium, Paracocus and Starkeya, which are taxonomically reassigned. The evaluation proved the excellent generalization capability of the developed tool. The topology of genera in SOM supported the conventional chemo-biochemical classification reported in the Bergey manual

Socio-economic position and cardiovascular risk in rural Indian adolescents: evidence from the Andhra Pradesh children and parents study (APCAPS).

OBJECTIVES: This study examined association between socio-economic position and cardiovascular risk factors in adolescents to investigate whether childhood socio-economic position is a risk factor for future cardiovascular disease, independently of adult behaviours. STUDY DESIGN AND METHODS: Participants (n = 1128, 46% girls, aged 13-18 years) were members of a birth cohort (Andhra Pradesh Children and Parents Study or APCAPS) established to investigate long-term effects of a pregnancy and childhood nutritional supplementation trial conducted in 29 villages near Hyderabad in South India. Cross-sectional associations between socio-economic position and cardiovascular risk factors were examined using linear regression models. RESULTS: The mean BMI was 16.7 kg/m(2) for boys and 17.8 kg/m(2) for girls. Socio-economic position was positively associated with fat mass index (0.15 kg/m(2); 95% CI: 0.05-0.25) and inversely associated with central-peripheral skinfold ratio (-0.04; 95% CI: -0.06 to -0.01) and, in boys, fasting triglycerides (-0.05; 95% CI: -0.09 to -0.01). Association of socio-economic position with other risk factors (blood pressure, arterial stiffness, fasting glucose, insulin and cholesterol) was weak and inconsistent, and did not persist after adjustment for potential confounders, including age, sex, pubertal stage, height, adiposity and nutrition supplementation. CONCLUSIONS: The study thus showed that lower socio-economic position may be associated with greater central adiposity and higher triglyceride levels in these settings. Socio-economic gradient in cardiovascular risk may strengthen in future with later economic and lifestyle changes. Cardiovascular disease prevention strategies should therefore focus on the youth from the low income group

Multiattribute electronic procurement using goal programming

One of the key challenges of current day electronic procurement systems is to enable procurement decisions transcend beyond a single attribute such as cost. Consequently, multiattribute procurement have emerged as an important research direction. In this paper, we develop a multiattribute e-procurement system for procuring large volume of a single item. Our system is motivated by an industrial procurement scenario for procuring raw material. The procurement scenario demands multiattribute bids, volume discount cost functions, inclusion of business constraints, and consideration of multiple criteria in bid evaluation. We develop a generic framework for an e-procurement system that meets the above requirements. The bid evaluation problem is formulated as a mixed linear integer multiple criteria optimization problem and goal programming is used as the solution technique. We present a case study for which we illustrate the proposed approach and a heuristic is proposed to handle the computational complexity arising out of the cost functions used in the bids