A Retrograde Spin of the Black Hole in MAXI J1659–152

We present the results of spectral analysis of the galactic black-hole binary MAXI J1659--152 in the rising phase of the outburst that lasted for about 65 days starting on 2010 September 25. The presence of a broad Fe line, verified by Monte-Carlo simulations, and coverage of a wide energy band by utilizing the combined spectral capabilities of XMM-Newton/EPIC-pn and RXTE/PCA allowed us to use a combination of reflection spectroscopy and continuum fitting methods to estimate the spin of the black hole. We explored the entire parameter range allowed by the present uncertainties on black-hole mass, inclination, and distance as well as the accretion rate. We show that for about 95 percentage of parameter space and very reasonable upper limits on mass accretion rate, the spin of the black hole has to be negative. This is the first clear detection of negative spin in a galactic black-hole binary.Comment: Published in ApJL. 9 pages, 4 figure

The X-ray corona in the black-hole binary GRO J1655--40 from the properties of non-harmonically related quasi-periodic oscillations

The study of quasi periodic oscillations (QPOs) plays a vital role in understanding the nature and geometry of the Comptonizing medium around black-hole X-ray binaries. The spectral-state dependence of various types of QPOs (namely A, B, & C) suggests that they could have different origins. The simultaneous presence of different types of QPOs would therefore imply the simultaneous occurrence of different mechanisms. In this work we study the radiative properties of two non-harmonically related QPOs in the black-hole binary GRO J1655--40 detected at the peak of the ultraluminous state during the 2005 outburst of the source. The two QPOs have been previously identified as types B & C, respectively. We jointly fit the phase-lag and rms spectra of the QPOs and the time-averaged spectrum of the source with the time-dependent Comptonization model vkompth to infer the geometry of the media producing the QPOs. The time-averaged spectrum required a hot disk of 2.3 keV and a steep power law with index 2.7, revealing that the source was in an ultraluminous state. The corona that drives the variability of the type-B QPO is smaller in size and has a lower feedback fraction than the one that drives the variability of the type-C QPO. This suggests the simultaneous presence of a horizontally extended corona covering the accretion disk and a vertically elongated jet-like corona that are responsible for the type-C & B QPOs, respectively.Comment: Accepted in MNRAS. 10 pages, 5 figures, 1 tabl

Physicochemical, Functional and Spectroscopic Analysis of Crawfish Chitin and Chitosan as Affected by Process Modification.

Traditional isolation of chitin from crawfish shells involves three sequential steps: demineralization (DM, removing calcium carbonate/phosphate), deproteinization (DP), and decolorization (DC, removing mainly astaxanthin). The first two steps can be reversed (i.e., DMP or DPM). Chitin is converted to chitosan by deacetylation (DA). Isolation steps may be shortened, depending on intended applications of chitosan. The first study investigated effects of (1) reversing sequence and (2) eliminating DP and DC steps on physicochemical and functional properties of chitosan and conversion efficiency of chitin. Twelve different processes: DM, DP, DPM, DMP, DPMC, DMPC, DMA, DMCA, DPMA, DMPA, DPMCA, DMPCA were investigated. DA of DPMC did not affect bulk density. Without DP and DC, bulk density of chitosan significantly increased. Nitrogen content of DMA-chitosan was 6.96% compared to 7.4--7.9% of commercial crab chitosans. DA removed 19% protein from demineralized shells. Deproteinized and demineralized shell once dried was not an effective substrate for decolorization. The conversion efficiency (CEF) of demineralized shell to non-deproteinized/non-decolorized chitosan (DMA) was 52.5%. The Water Binding Capacity (WBC) and Fat Binding Capacity (FBC) of the crawfish chitins were compared with those of commercial chitin and chitosans. This study shows that isolation steps for chitosan production can be reduced, which, in turn, would lower production cost and produce less chemical wastes compared to the traditional process. Several methods are available for determining (Degree of Deacetylation) DD, including NMR, linear potentiometric titration, ninhydrin test, and first derivative UV-spectrophotometry. The second study was aimed to develop the method to determine DD and purity of crawfish chitin and chitosan using FTIR spectroscopy. Chitin and chitosan with various DD were finely ground (0.5mm), oven-dried at 95°C, and analyzed for DD and purity using FTIR spectroscopy. The spectral region of 1200--1800 cm-1 was the information rich-region. DD of chitosan was estimated using the ratio of absorption at 1655 and 3450 cm-1 . Chitosan with DD of 75, 80, 85 and 91 showed similar FTIR spectra pattern. The FTIR spectroscopy may serve as a rapid method to determine DD and purity of chitosan

Revisiting the galactic X-ray binary MAXI J1631-479: Implications for high inclination and a massive black hole

X-ray spectroscopy of galactic black hole binaries serve as a powerful tool to gain an overall understanding of the system. Not only can the properties of the accretion disk be studied in detail, the fundamental properties of the black hole can also be inferred. The pursuit of these objectives also leads to an indirect validation of general relativity in strong field limit. In this work we carry out a comprehensive spectral analysis of the galactic X-ray binary MAXI J1631-479 using data from NICER and NuSTAR observatories. We trace the evolution of the accretion disk properties such as density, ionization, Fe abundance, etc as the source transitions from a disk dominated soft state to a power law dominated hard intermediate state. We provide strong constrains on the spin of the black hole and the inclination of the inner disk. We also use the soft state NICER observations to constrain the black hole mass using distance estimates from optical observations.Comment: 15 pages, 6 figures, 1 table. Accepted in the Astrophysical Journa

DESIGN OF EFFICIENT DELAY BLOCK FOR LOW FREQUENCY APPLICATION

In recent years researchers have been  focusing on the design of low power and small size oscillator for emerging areas of interest such as the internet of things (IoT) and biomedical applications. In this paper a new delay block for ring oscillator is proposed using CMOS inverter cascaded with inverted current starved inverter (CICSI). The designed delay block provides approximately 50% more delay with a smaller number of transistors than the conventionally designed circuits. Furthermore, a ring oscillator and a non-overlapping clock (NOC) generator are designed using it. The designed circuits can be used in switched capacitor (SC) circuits, analog mixed signal circuits to meet the need for low frequency portable biomedical applications. The designed circuits are simulated on Generic 90nm 1.2V Process Design Kit (GPDK90) using Cadence Virtuoso Design Environment. The simulation result shows the delay of the CICSI delay block is 592ps. The ring oscillator using 101 stages of delay block is designed and it is shown that it operates at a frequency of  17MHz with a power consumption of 420µW

Spectral and timing evolution of MAXI J1631-479 during the 2018-19 outburst with NICER

The X-ray transient MAXI J1631-479 went into outburst on 2018 December 21 and remained active for about seven months. Owing to various constraints it was monitored by NICER only during the decay phase of the outburst for about four months. The NICER observations were primarily in the soft state with a brief excursion to the hard intermediate state. While the soft state spectrum was dominated by thermal disc emission, the hard intermediate state spectrum had maximum contribution from the thermal Comptonization. Almost all intermediate-state power spectra had a Type-C low frequency quasi-periodic oscillation (within 4-10Hz), often accompanied by a harmonic component. The frequency of these oscillations increased and the fractional rms decreased with inner-disc temperature suggesting a geometric origin. The rms spectra during the intermediate state had a hard shape from above 1keV. Below 1keV the shape could not be constrained in most cases, while only a few observations showed a rise in amplitude

Has the Public Health System Provided Adequate Financial Risk Protection for Child Birth Conditions – Evidences From an Eastern Indian State

Over the years, national and sub-national governments have introduced several initiatives to improve access to maternal and child health services in India. However, financial barriers have posed major constraints. Based upon the data of National Family Health Survey (NFHS) round 4 for Odisha state, our paper examines the out-of-pocket expenditure (OOPE) borne by households for accessing maternal and child healthcare services in a low resource setting of India. We have interpreted results of NFHS-4 by drawing inferences from literature for understanding the rising OOPE in the public health system. Findings suggests that OOPE is considerably high for maternal and child health conditions in Odisha and ranks fifth, despite the coverage of 72% women under Janani Suraksha Yojana (JSY), a condition cash transfer scheme with majority utilizing the public health system. The high OOPE on child delivery raises numerous pertinent questions about the effectiveness of the public health delivery system, and thus requires financial protection in the interest of the population that accesses public health systems in the state

Skull Evolution Method and Analysis in The Rhinocerotidae: Phylogeny of Early Rhinocerotoids

After phylogeny is measurably disposed of, cranial elements utilized essentially for rumination ought to change most with hypsodonty (high-delegated cheek teeth). These structures should be least phylogenetically restricted. Corollary: structures with significant common ancestry will integrate more morphologically. All living rhinoceroses and many extinct European Plio-Pleistocene species We examined skull, mandible, and upper tooth row form in the dorsal, lateral, and occlusal perspectives using two-dimensional geometric morphometrics. Hypsodonty index was employed to represent eating behaviours. We divided form variation into function, phylogeny, and size using phylogenetically independent comparisons and variation partitioning. We used Escoufier's RV coefficient to evaluate morphological reconciliation. The mandible and upper tooth column covariate most with hypsodonty and least with phylogeny. Skull morphology corresponds least with hypsodonty and most with phylogeny. Low morphological joining between the top tooth line and different parts recommends it is the least phylogenetically restricted. As predicted, the chewing area is confined by function rather than phylogeny, unlike others

Entrepreneurial Behaviour of the Agriculture Students-A review

The present study aimed to investigate the factors that influence the entrepreneurial behavior of college students. The study identified various personal and situational factors that may affect entrepreneurial behavior. The results showed that personality traits, such as openness, extraversion, and conscientiousness, had a significant positive impact on entrepreneurial behavior. Specific motivational traits, such as entrepreneurial self-efficacy, internal locus of control, and risk-taking propensity, were also significant predictors of entrepreneurial behavior. Situational factors, such as entrepreneurship education, were found to have a significant positive impact on entrepreneurial behavior, with entrepreneurial self-efficacy playing a key mediating role in this relationship. Attitudes towards entrepreneurship were found to be a significant driver of entrepreneurial intention, with perceived desirability and feasibility, as well as perceived individual and collective efficacy, also significant predictors of entrepreneurial intention. Sustainable entrepreneurial intention was found to be influenced by attitude towards the behavior variable, with subjective norms playing an indirect role in mediating this effect. Overall, the study suggests that personal traits, such as personality and motivational factors, as well as situational factors, such as education and attitudes towards entrepreneurship, are significant predictors of entrepreneurial behavior. These findings have important implications for educators and policymakers who seek to promote entrepreneurial behavior among college students. Future research should continue to explore the complex relationships between personal and situational factors and entrepreneurial behavior to further enhance our understanding of this important phenomenon. &nbsp