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V382 Vel: a "shocking" supersoft x-ray source? [article]

Marina Orio, Arvind Parmar
2001 arXiv   pre-print
Nova Vel 1999 (V382 Vel) was observed with BeppoSAX twice, 15 days and 6 months after the optical maximum. A hard X-ray source was detected in the first observation, while the second time also a very luminous supersoft X-ray source was detected. The continuum observed in the supersoft range with the BeppoSAX LECS cannot be fitted with atmospheric models of hot hydrogen burning while dwarfs. We suggest that we are observing instead mainly a "pseudocontinuum", namely a blend of very strong emission lines in the supersoft X-ray range.
arXiv:astro-ph/0102440v1 fatcat:oveogkpzdjchxh6pqhq5lprbsa

ASCA observation of 4U1624–49

Lorella Angelini, Arvind Parmar, Nicholas White
1997 International Astronomical Union Colloquium  
Observation and Results Several low mass X-ray binaries exhibit periodic irregular dips in their X-ray lightcurves (see White, Nagase, & Parmar 1995 for a review). 4U1624-49 shows perhaps the most dramatic  ... 
doi:10.1017/s0252921100043414 fatcat:3qnvw5yzrney7mjs7apiqgc5wm

Theory and Experiments on Vector Quantized Autoencoders [article]

Aurko Roy, Ashish Vaswani, Arvind Neelakantan, Niki Parmar
2018 arXiv   pre-print
Deep neural networks with discrete latent variables offer the promise of better symbolic reasoning, and learning abstractions that are more useful to new tasks. There has been a surge in interest in discrete latent variable models, however, despite several recent improvements, the training of discrete latent variable models has remained challenging and their performance has mostly failed to match their continuous counterparts. Recent work on vector quantized autoencoders (VQ-VAE) has made
more » ... ntial progress in this direction, with its perplexity almost matching that of a VAE on datasets such as CIFAR-10. In this work, we investigate an alternate training technique for VQ-VAE, inspired by its connection to the Expectation Maximization (EM) algorithm. Training the discrete bottleneck with EM helps us achieve better image generation results on CIFAR-10, and together with knowledge distillation, allows us to develop a non-autoregressive machine translation model whose accuracy almost matches a strong greedy autoregressive baseline Transformer, while being 3.3 times faster at inference.
arXiv:1805.11063v2 fatcat:q4hfp6fftjfjhpusgx6ydx5tpm

The International X-ray Observatory [article]

Nicholas E. White, Arvind Parmar, Kirpal Nandra (Imperial College London), Takaya Ohashi, Jay Bookbinder
2010 arXiv   pre-print
The International X-ray Observatory (IXO) is a joint ESA-JAXA-NASA effort to address fundamental and timely questions in astrophysics: What happens close to a black hole? How did supermassive black holes grow? How does large scale structure form? What is the connection between these processes? To address these questions IXO will employ optics with 3 sq m collecting area and 5 arc sec angular resolution - 20 times more collecting area at 1 keV than any previous X-ray observatory. Focal plane
more » ... ruments will deliver a 100-fold increase in effective area for high-resolution spectroscopy, deep spectral imaging over a wide field of view, unprecedented polarimetric sensitivity, microsecond spectroscopic timing, and high count rate capability. The mission is being planned for launch in 2021 to an L2 orbit, with a five-year lifetime and consumables for 10 years.
arXiv:1001.2843v1 fatcat:6ede7scmxngslbohsnwmap6kim

The Challenges of Delta Variant of Coronavirus and Indian Vaccinations Can Envision the Coronavirus and Its Effects

Jitendra Malviya, Arvind Parmar, Lokesh Parmar, Roshni Khan, Rituja Roy, Sushmita Kanade, Prince Giri, Balram Rathore
2021 American Journal of Biomedical and Life Sciences  
Since the outbreak of the novel corona virus disease COVID-19, precipitated by way of the SARS-CoV-2 virus, this sickness has unfolded hastily round the globe. Considering the practicable risk of a pandemic, scientists and medical doctors have been racing to apprehend this new virus and the pathophysiology of this disorder to discover feasible therapy regimens and find out fantastic therapeutic sellers and vaccines. To guide the cutting-edge lookup and development, CAS has produced a
more » ... ry record to furnish an overview of posted scientific statistics with an emphasis on patents in the CAS content material collection. It highlights antiviral techniques involving small molecules and biologics concentrated on complicated molecular interactions concerned in corona virus contamination and replication. The drug-repurposing effort documented herein focuses principally on dealers recognized to be superb in opposition to different RNA viruses such as SARS-CoV and MERS-CoV. The current secondary data have been chosen for the study while text 16 research articles to focus the study. The review is focus on that the challenges of coronaviruses and the new strains in Indian population due to constantly virus has changed through mutation appeared and disappeared too the more diverse and spread easily and resistant to treatments or vaccines. The vaccination in India is slow rate due to unavailability of the raw materials; the two Indian vaccine development companies have not able to provided vaccines as per the requirement. Unawareness has also been a biggest problem to the pandemic situation in the second wave of the coronavirus with new variants. The present study is deals with the challenges of new variants of coronavirus; the conditions of health system; Crisis of medicine, oxygen cylinder, failure of management increase more cases and finally the vaccination process; management and availability.
doi:10.11648/j.ajbls.20210904.16 fatcat:sz4l2jve6fcxdjd46jyesmo3sq

Contribution of point sources to the soft gamma-ray Galactic emission [article]

Regis Terrier, Francois Lebrun, Guillaume Belanger, Andrea Goldwurm, Andrew W. Strong, Volker Schoenfelder, Laurent Bouchet, Jean-Pierre Roques, Arvind Parmar
2004 arXiv   pre-print
The nature of the soft gamma-ray (20-200 keV) Galactic emission has been a matter of debate for a long time. Previous experiments have tried to separate the point source contribution from the real interstellar emission, but with a rather poor spatial resolution, they concluded that the interstellar emission could be a large fraction of the total Galactic emission. INTEGRAL, having both high resolution and high sensitivity, is well suited to reassess more precisely this problem. Using the
more » ... L core program Galactic Center Deep Exposure (GCDE), we estimate the contribution of detected point sources to the total Galactic flux.
arXiv:astro-ph/0405207v1 fatcat:heznfw3vkvedtfuq667nalp2p4

Partial wavelet coherence analysis for understanding the standalone relationship between Indian Precipitation and Teleconnection patterns [article]

Maheswaran Rathinasamy, Ankit Agarwal, Vilakshna Parmar, Rakesh Khosa, Arvind Bairwa
2017 arXiv   pre-print
Hydro-meteorological variables, like precipitation, streamflow are significantly influenced by various climatic factors and large-scale atmospheric circulation patterns. Efficient water resources management requires an understanding of the effects of climate indices on the accurate predictability of precipitation. This study aims at understanding the standalone teleconnection between precipitation across India and the four climate indices, namely, Ni\~no 3.4, PDO, SOI, and IOD using partial
more » ... let analysis. The analysis considers the cross correlation between the climate indices while estimating the relationship with precipitation. Previous studies have overlooked the interdependence between these climate indices while analysing their effect on precipitation. The results of the study reveal that precipitation is only affected by Ni\~no 3.4 and IOD and a non-stationary relationship exists between precipitation and these two climate indices. Further, partial wavelet analysis revealed that SOI and PDO do not significantly affect precipitation, but seems the other way because of their interdependence on Ni\~no 3.4. It was observed that partial wavelet analysis strongly revealed the standalone relationship of climatic factors with precipitation after eliminating other potential factors. Keywords: Indian Precipitation, wavelet coherency, partial wavelet coherence, teleconnections patterns.
arXiv:1702.06568v1 fatcat:nfuvb2w6tbhh5ozdz6m3qkwpcy

Low-energy line emission from Cygnus X-2 observed by the BeppoSAX LECS

Erik Kuulkers, Arvind N. Parmar, Alan Owens, Tim Oosterbroek, Uwe Lammers
1997 AIP Conference Proceedings  
The ground calibration of the LECS is discussed in Parmar et al. (1997) .  ... 
doi:10.1063/1.53997 fatcat:3txprhbtynf2rbbwaefk35k5bu

Translocator Protein Localises To CD11b+ Macrophages In Atherosclerosis [article]

Chantal Kopecky, Elvis Pandzic, Arvind Parmar, Jeremy Szajer, Victoria Lee, Alexander Dupuy, Andrew Arthur, Sandra Fok, Renee Whan, William J Ryder, Kerry-Anne Rye, Blake J Cochran
2018 bioRxiv   pre-print
Atherosclerosis is characterized by lipid deposition, monocyte infiltration and foam cell formation in the artery wall. Translocator protein (TSPO) is abundantly expressed in lipid rich tissues. Recently, TSPO has been identified as a potential diagnostic tool in cardiovascular disease. The purpose of this study was to determine if the TSPO ligand, 18F-PBR111, can identify early atherosclerotic lesions and if TSPO expression can be used to identify distinct macrophage populations during lesion
more » ... rogression. Methods and Results: ApoE-/- mice were maintained on a high-fat diet for 3 or 12 weeks. C57BL/6J mice maintained on chow diet served as controls. Mice were administered 18F-PBR111 intravenously and PET/CT imaged. After euthanasia, aortas were isolated, fixed and optically cleared. Cleared aortas were immunostained with DAPI, and fluorescently labelled with antibodies to-TSPO, the tissue resident macrophage marker F4/80 and the monocyte-derived macrophage marker CD11b. TSPO expression and the macrophage markers were visualised in fatty streaks and mature lesions by light sheet microscopy. While tissue resident F4/80+ macrophages were evident in the arteries of animals without atherosclerosis, no CD11b+ macrophages were observed in these animals. In contrast, mature plaques had high CD11b and low F4/80 expression. A ~3-fold increase in the uptake of 18F-PBR111 was observed in the aortas of atherosclerotic mice relative to controls. Conclusions: Imaging of TSPO expression is a new approach for studying atherosclerotic lesion progression and inflammatory cell infiltration. The TSPO ligand, 18F-PBR111, is a potential clinical diagnostic tool for the detection and quantification of atherosclerotic lesion progression in humans.
doi:10.1101/494377 fatcat:k26f5ys5wfci3pvtgt3m2tkjgm

Estimation of Runoff for Ozat Catchment using RS and GIS Based SCS-CN Method

Dipesh Chavda, Jaydip Makwana, Hitesh Parmar, Arvind Kunapara, Girish Prajapati
2016 Current World Environment  
Estimation of runoff in a watershed is a prerequisite for design of hydraulic structures, reservoir operation and for soil erosion control measures. Water resource planning and management is important and critical issue in arid and semi-arid regions. Runoff from a watershed affected by several geo-morphological parameters and for a particular watershed land use change can affect the runoff volume and runoff rate significantly. Several methods are investigated to estimate the surface runoff from
more » ... a catchment but the Curve Number method is mostly used. Present study was undertaken to estimate surface runoff and water availability for two sites (Ozat-2 and Zanzesri) in the Ozat catchment situated in Junagadh, Gujarat, India using RS and GIS based curve number method. The Weight curve number for the ozat catchment is 73.00. The correlation coefficient between calculated and observed runoff was good for both catchments. In this study found that SCS-curve number method along with RS and GIS can be used successfully in semi-arid region to estimate runoff and to estimate total surface water.
doi:10.12944/cwe.11.1.26 fatcat:pln3gvk56fao5c4em7vcsjm5nq

BeppoSAX Observations of the galactic source GS1826-238 in a hard X-ray high state [article]

Stefano Del Sordo, Filippo Frontera, Elena Pian, Santina Piraino, Tim Oosterbroek, B.A. Harmon, Eliana Palazzi, Marco Tavani, S.N. Zhang, Arvind Parmar
1999 arXiv   pre-print
The BeppoSAX Narrow Field Instruments observed the galactic source GS1826-238 in October 1997, following a hard X-ray outburst with a peak flux of about 100 mCrab detected by BATSE. Two short X-ray bursts (about 150 s) were detected up to 60 keV, with larger amplitude and duration at lower energies(up to a factor 20 times the persistent emission). This confirms the proposed identification of the source as a weakly magnetized neutron star in a LMXRB system. For both persistent and burst states,
more » ... he spectrum in the 0.4-100 keV energy range is well fitted by an absorbed blackbody, plus a flat power-law with an exponential cutoff at 50 keV.
arXiv:astro-ph/9901203v1 fatcat:amhsdvbogjg6vedmdosfngsayy

Studies in 3,4-diaryl-1,2,5-oxadiazoles and their N-oxides: Search for better COX-2 inhibitors

Mange Yadav, Shrikant Shirude, Devendra Puntambekar, Pinkal Patel, Hetal Prajapati, Arvind Parmar, R. Balaraman, Rajani Giridhar
2007 Acta Pharmaceutica  
Studies in 3,4-diaryl-1,2,5-oxadiazoles and their N-oxides: Search for better COX-2 inhibitors A series of 3,4-diaryl-1,2,5-oxadiazoles and 3,4-diaryl-1,2,5-oxadiazole N-oxides were prepared and evaluated for COX-2 and COX-1 binding affinity in vitro and for anti-inflammatory activity by the rat paw edema method. p-Methoxy (p-OMe) substituted compounds 9, 21, 34, 41, 42 showed COX-2 enzyme inhibition higher than that showed by compounds with other substituents.
more » ... iazole N-oxide (42) showed COX-2 enzyme inhibition of 54% at 22 μmol L-1 and COX-1 enzyme inhibition of 44% at 88 μmol L-1 concentrations, but showed very low in vivo anti-inflammatory activity. Its deoxygenated derivative (21) showed lower COX-2 enzyme inhibition (26% at 22 μmol L-1) and higher COX-1 enzyme inhibition (53% at 88 μmol L-1) but, marked in vivo anti-inflammatory activity (71% at 25 mg kg-1) vs. celecoxib (48% at 12.5 mg kg-1). Molecular modeling (docking) studies showed that the methoxy group is positioned in the vicinity of COX-2 secondary pocket and it also participates in hydrogen bonding interactions in the COX-2 active site. These preliminary studies suggest that p-methoxy (p-OMe) group in one of benzene rings may give potentially active leads in this series of oxadiazole/N-oxides.
doi:10.2478/v10007-007-0002-z pmid:19839404 fatcat:jh3v6woz6fbc7k3v7zbyifirui

Haemato-biochemical Alterations in Sheep Due to Experimentally Induced Haemonchus contortus Infection

Dipali Parmar, Dinesh Chandra, Arvind Prasad, Ekta Singh, Navneet Kaur, Abdul Nasir
2019 International Journal of Current Microbiology and Applied Sciences  
doi:10.20546/ijcmas.2019.805.280 fatcat:5c3epk7uv5cjzmd62mgzv2pn6i

Women's views on autologous cell-based therapy for post-obstetric incontinence

Bernice Wright, Anton Emmanuel, Eleni Athanasakos, Nina Parmar, Georgina Parker, Belinda Green, Emma Tailby, Heidi Chandler, Julyette Cushnie, June Pembroke, Yvonne Saruchera, Arvind Vashisht (+1 others)
2016 Regenerative Medicine  
Aim: Fecal and urinary incontinence are devastating consequences of obstetricrelated perineal injury. The aim of the present study is to determine acceptability to parous women of autologous cell-based therapy for fecal and urinary incontinence that arises due to pelvic diaphragm tearing during vaginal childbirth. Materials & methods: A multiple choice questionnaire survey was offered to 76 parous women at the Maternity Unit, University College Hospital, London, UK. Seventy completed
more » ... res -response rate: 92%. Results: In total, 84% of women indicated a willingness to accept autologous cell-based therapy for obstetric injury-induced incontinence rather than surgery. Conclusion: These observational data provide an indication of likely acceptance of autologous cell-based therapies for birth injury incontinence and will help with designing new therapeutic approaches.
doi:10.2217/rme.15.88 pmid:26876964 fatcat:fdib2brzgrghpieod4sv3viqj4

Ambiguities in Fits to the Complex X‐Ray Spectra of Starburst Galaxies

Michael Dahlem, Arvind Parmar, Tim Oosterbroek, Astrid Orr, Kimberly A. Weaver, Timothy M. Heckman
2000 Astrophysical Journal  
Spectral fits to X-ray data from both NGC 253 and M 82 provide ambiguous results. The so-called "best fit" results depend on the instrument with which the data were obtained and obviously on the choice of spectral model composition. We show that different spectral models can be fit equally well to BeppoSAX data of both galaxies. Metallicities are unreliable in general, with a strong dependence on the choice of model. Preference to one particular spectral model can only be given by combining
more » ... troscopic and imaging X-ray data from all available satellites (ROSAT, ASCA, and BeppoSAX). Based on spectra of NGC 253, we demonstrate that a model consisting of two or more thermal plasma components plus a hard power law continuum and Fe K alpha line emission can explain all observations. These model components represent the integral spectrum of thermal gas and compact sources in starburst galaxies that are most likely supernova remnants and X-ray binaries. The same model can fit the X-ray data of M 82, but there the evidence, from ROSAT imaging, of the existence of compact sources which might represent high-mass X-ray binaries is weaker. This implies that its hard X-ray emission, which is extended in ROSAT images, might - if truly diffuse - be dominated by a very hot (several keV energy) thermal gas component.
doi:10.1086/309186 fatcat:rjncepmazrgerb2ix7wtitgfiq
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