ABSTRACT We present extensive multiwavelength (radio to X-ray) observations of the Type Ib/c supernova (SN Ib/c) SN 2013ge from −13 to +457 days relative to maximum light, including a series of ...optical spectra and Swift UV-optical photometry beginning 2-4 days post-explosion. This data set makes SN 2013ge one of the best-observed normal SNe Ib/c at early times-when the light curve is particularly sensitive to the progenitor configuration and mixing of radioactive elements-and reveals two distinct light curve components in the UV bands. The first component rises over 4-5 days and is visible for the first week post-explosion. Spectra of the first component have blue continua and show a plethora of moderately high velocity (∼15,000 km s−1) but narrow (∼3500 km s−1) spectroscopic features, indicating that the line-forming region is restricted. The explosion parameters estimated for the bulk explosion ( M ej ∼ 2-3 M ; E K ∼ (1-2) × 1051 erg) are standard for SNe Ib/c, and there is evidence for weak He features at early times-in an object that would have otherwise been classified as Type Ic. In addition, SN 2013ge exploded in a low-metallicity environment (∼0.5 Z ), and we have obtained some of the deepest radio and X-ray limits for an SN Ib/c to date, which constrain the progenitor mass-loss rate to be M ˙ < 4 × 10−6 M yr−1. We are left with two distinct progenitor scenarios for SN 2013ge, depending on our interpretation of the early emission. If the first component is cooling envelope emission, then the progenitor of SN 2013ge either possessed an extended ( 30 R ) envelope or ejected a portion of its envelope in the final 1 yr before core collapse. Alternatively, if the first component is due to outwardly mixed 56Ni, then our observations are consistent with the asymmetric ejection of a distinct clump of nickel-rich material at high velocities. Current models for the collision of an SN shock with a binary companion cannot reproduce both the timescale and luminosity of the early emission in SN 2013ge. Finally, the spectra of the first component of SN 2013ge are similar to those of the rapidly declining SN 2002bj.
ABSTRACT We study the late-time ( days) X-ray afterglows of nearby ( ) long gamma-ray bursts (GRBs) with Swift and identify a population of explosions with slowly decaying, super-soft (photon index ) ...X-ray emission that is inconsistent with forward shock synchrotron radiation associated with the afterglow. These explosions also show larger-than-average intrinsic absorption ( ) and prompt γ-ray emission with extremely long duration ( s). The chance association of these three rare properties (i.e., large , super-soft , and extreme duration) in the same class of explosions is statistically unlikely. We associate these properties with the turbulent mass-loss history of the progenitor star that enriched and shaped the circumburst medium. We identify a natural connection between , , and in these sources by suggesting that the late-time super-soft X-rays originate from radiation reprocessed by material lost to the environment by the stellar progenitor before exploding (either in the form of a dust echo or as reprocessed radiation from a long-lived GRB remnant), and that the interaction of the explosion's shock/jet with the complex medium is the source of the extremely long prompt emission. However, current observations do not allow us to exclude the possibility that super-soft X-ray emitters originate from peculiar stellar progenitors with large radii that only form in very dusty environments.
We report the Swift discovery of the nearby long, soft gamma-ray burst GRB100316D, and the subsequent unveiling of its low-redshift host galaxy and associated supernova. We derive the redshift of the ...event to be z= 0.0591 ± 0.0001 and provide accurate astrometry for the gamma-ray burst (GRB) supernova (SN). We study the extremely unusual prompt emission with time-resolved γ-ray to X-ray spectroscopy and find that the spectrum is best modelled with a thermal component in addition to a synchrotron emission component with a low peak energy. The X-ray light curve has a remarkably shallow decay out to at least 800 s. The host is a bright, blue galaxy with a highly disturbed morphology and we use Gemini-South, Very Large Telescope and Hubble Space Telescope observations to measure some of the basic host galaxy properties. We compare and contrast the X-ray emission and host galaxy of GRB100316D to a subsample of GRB-SNe. GRB100316D is unlike the majority of GRB-SNe in its X-ray evolution, but resembles rather GRB060218, and we find that these two events have remarkably similar high energy prompt emission properties. Comparison of the host galaxies of GRB-SNe demonstrates, however, that there is a great diversity in the environments in which GRB-SNe can be found. GRB100316D is an important addition to the currently sparse sample of spectroscopically confirmed GRB-SNe, from which a better understanding of long GRB progenitors and the GRB-SN connection can be gleaned. PUBLICATION ABSTRACT
Fine quality Cu2ZnSnS4 (CZTS) thin films were prepared by a non-toxic, simple and economical sol–gel and spin-coating technique. The CZTS thin films were prepared on Molybdenum coated soda lime glass ...substrates. The films were annealed at three different temperatures viz. 525, 550 and 575°C under H2S gas atmosphere to study the effect of annealing temperature on the morphological, structural, chemical, compositional, optical and photovoltaic properties of the CZTS thin films. The X-ray diffraction and Raman spectroscopy investigations on the CZTS thin films showed formation of the pure kesterite structure. The X-ray fluorescence studies demonstrated that all the CZTS thin films were nearly stoichiometric having Zn rich composition. All the annealed films were further subjected to fabrication of solar cells as an SLG/Mo/CZTS/CdS/i-ZnO/AZO/Al grid. The best solar cell showed a short-circuit current density of 14.57mA/cm2, open-circuit voltage of 513mV, fill factor of 40% and power conversion efficiency of 3.01% under air mass 1.5 (100mW/cm2) illumination.
•A 3.01% efficient CZTS solar cell is prepared using 575°C annealed thin film.•The method is facile, economic and environmentally benign.•All the CZTS thin films have a single phase polycrystalline kesterite crystal structure.
Abstract
India and other agricultural countries grow large quantities of sugar cane and ethanol is a by-product of the sugarcane industry. The blending of ethanol with petrol can save tremendous ...amount of petrol. In the present study, experiment was carried on the SI engine by means of various blends of ethanol with petrol such as E5, E8, E10 and E12, and the various engine performance variables were recorded such as brake thermal efficiency, volumetric efficiency, air-to-fuel ratio and exhaust heat. The two selected multi attribute decision making methods viz: technique for order preference by similar to ideal solution and compromise ranking method have been utilized in determining the rank of blends. It has been seen from the ranks obtained using both the methods that the blend E10 is the best alternative with petrol, E5 is the second best where as E8 and E12 are third and fourth best alternative respectively.
► Synthesis of nanocrystalline ZnO thin films onto glass and ITO coated glass substrates by SPT. ► The substrate temperature dependent properties of ZnO thin films were investigated. ► The sample ...deposited at 450
°C shows the better photoelectrochemical performance.
A simple and inexpensive spray pyrolysis technique (SPT) was employed for the synthesis of nanocrystalline zinc oxide (ZnO) thin films onto soda lime glass and tin doped indium oxide (ITO) coated glass substrates at different substrate temperatures ranging from 300
°C to 500
°C. The synthesized films were polycrystalline, with a (0
0
2) preferential growth along
c-axis. SEM micrographs revealed the uniform distribution of spherical grains of about 80–90
nm size. The films were transparent with average visible transmittance of 85% having band gap energy 3.25
eV. All the samples exhibit room temperature photoluminescence (PL). A strong ultraviolet (UV) emission at 398
nm with weak green emission centered at 520
nm confirmed the less defect density in the samples. Moreover, the samples are photoelectrochemically active and exhibit the highest photocurrent of 60
μA, a photovoltage of 280
mV and 0.23 fill factor (FF) for the Zn
450 films in 0.5
M Na
2SO
4 electrolyte, when illuminated under UV light.
We present late-time radio and X-ray observations of the nearby sub-energetic gamma-ray burst (GRB)100316D associated with supernova (SN) 2010bh. Our broad-band analysis constrains the explosion ...properties of GRB 100316D to be intermediate between highly relativistic, collimated GRBs and the spherical, ordinary hydrogen-stripped SNe. We find that ~10 super(49) erg is coupled to mildly relativistic (Gamma = 1.5-2), quasi-spherical ejecta, expanding into a medium previously shaped by the progenitor mass-loss with a rate of M ~ 10 super(-5) M sub(middot in circle) yr super(-1) (for an assumed wind density profile and wind velocity v sub(w) = 1000 kms super(-1)). The kinetic energy profile of the ejecta argues for the presence of a central engine and identifies GRB 100316D as one of the weakest central-engine-driven explosions detected to date. Emission from the central engine is responsible for an excess of soft X-ray radiation that dominates over the standard afterglow at late times (t > 10 days). We connect this phenomenology with the birth of the most rapidly rotating magnetars. Alternatively, accretion onto a newly formed black hole might explain the excess of radiation. However, significant departure from the standard fail-back scenario is required.
We present Hubble Space Telescope optical and ultraviolet photometry for five nearby, thermally emitting neutron stars. With these measurements, all seven such objects have confirmed optical and ...ultraviolet counterparts. Combining our data with archival space-based photometry, we present spectral energy distributions for all sources and measure the 'optical excess': the factor by which the measured photometry exceeds that extrapolated from X-ray spectra. We find that the majority have optical and ultraviolet fluxes that are inconsistent with that expected from thermal (Rayleigh-Jeans) emission, exhibiting more flux at longer wavelengths. We also find that most objects have optical excesses between 5 and 12, but that one object (RX J2143.0+0654) exceeds the X-ray extrapolation by a factor of more than 50 at 5000 A, and that this is robust to uncertainties in the X-ray spectra and absorption. We consider explanations for this ranging from atmospheric effects, magnetospheric emission, and resonant scattering, but find that none is satisfactory.
Background: Cervical Papanicolaou (PAP) smear is the simplest, minimal invasive, and excellent screening method to reduce the female morbidity and mortality due to cervical carcinoma. Immediate ...alcohol fixation of the cervical smears is required to preserve nuclear details, delay in alcohol fixation leads to air drying artifacts. Rehydrating of the air-dried cervical pap smear with normal saline can help to overcome these artifacts and also have its own advantages. Aims: This study was design to evaluate the effects, merits and pitfalls of normal saline Rehydrated Air-Dried Cervical PAP Smears (RADPS) compared with the Conventional Papanicolaou Smear (C-PAPS). Settings and Design: Comparative study. Methods and Material: Prospectively paired cervical smears of 100 women, who presented to the outpatient department of gynecology of our institute, were prepared. Alcohol fixed smears were labelled as conventional Papanicolaou smear (C-PAPS) and air-dried smears labelled as rehydrated air-dried PAP smears (RADPS). Eight cytomorphological parameters were considered for comparison and analyzed. Statistical analysis used: Chisquare (χ2)/Fisher exact test. Results: Clear background with red blood cells (RBC) lysis was noted in 93% of RADPS and 54% of C-PAPS. Cytolysis was observed more in C-PAPS (18%) than in RADPS (08%). Air-drying artifacts observed in 30% of C-PAPS and 08% of RADPS. Cytoplasmic staining (92% of RADPS and 85% of C-PAPS) was superior in RADPS. Cell border, nuclear chromatin, and border were also better appreciated on RADPS as compared to C-PAPS. Statistically significant difference was observed with 3 parameters, i.e., air-drying artifacts, RBC background, and distinct cell borders. Conclusion: Rehydration of air-dried smears can be adopted in regular practice, as an alternative or coupled with conventional wet fixation method to overcome the commonly faced problems of air-drying artifacts, especially in rural screening programs.
Introduction
There is growing evidence of neuropsychiatric presentations in patients of COVID-19, but literature is scarce on laboratory, clinical and radiological markers as well as impact of ...psychotropic medications during the course of hospitalization in critically ill patients.
Objectives
The primary outcome measure was variability of clinical biomarkers and CORADS scores with severity of COVID-19 infections and the impact of psychotropic medications like risperidone and aripiprazole.
Methods
We screened 430 ICU patients admitted to our tertiary care hospitals, out of whom 67 were diagnosed positively with definitive neuropsychiatric sequalae and receive psychotropic interventions during their hospital stay. We compared their D-dimer levels, C-reactive proteins, serum ferritin levels, serum procalcitonin and Vitamin D levels and further analyzed CORADS severity score with psychiatric severity and outcome.
Results
The mean age of the patients was 42.38 years, majority (44.8%) of them belonged to 21-34 years with slight (52.2%) male preponderance and none of them were more than 60 years. We observed a 43.3% were having organic mood disorder and 37.3% of individual had significant history of alcohol dependence while hypertension and diabetes mellitus were noted in 34.3% and 29.9% respectively. Only D-dimer levels were found to be significant and positively associated with outcome of psychiatric disorders (p<0.05), accounting for 41% of covariance on linear regression analysis.
Conclusions
Our study has found significant association of elevated levels of D-dimer variability but not the other laboratory biomarkers among various neuropsychiatric comorbid sequalae in ICU admitted COVID 19 patients. This particular observation might have potential for serum D-dimer levels to be possibly used as an early biomarker to screen or suspect for comorbid neuropsychiatric presentations.
Disclosure of Interest
None Declared
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