174 research outputs found
Narrow band photometry of selected asteroids
The CCD photometry of selected asteroids was carried out to check for possible cometary activity in them. To distinguish the asteroids with possible cometary activity from those of the main belt, each object of interest was observed in two filters; one centered on the C2 emission band at 5140A (90A bandpass) and the other centered on the nearby continuum at 4845A (65A bandpass). None of the observed asteroids appear to have any C2 emission
Early observations of the Afterglow of GRB000301c
We report multiband observations of the Optical Transient (OT) associated
with GRB000301c carried out between 2--4 March 2000 using the 2.34-m Vainu
Bappu Telescope (VBT) at Kavalur, India. When combined with other reported
data, the initial decline in the R-band magnitude with log (), the time
since the burst is fit with a slope = -0.70 0.07 which
steepens after about 6.0 days to a slope of = -2.44 0.29.
This change in slope does not occur smoothly but there is an indication for a
bimodal distribution. The available measurements of the evolution of (B--R)
color do not show any discernible evolution in the first 12 days.Comment: 14 pages, 2 postscript figures, Accepted for Publication in ApJ
Letter
On the Clustering of GRBs on the Sky
The two-point correlation of the 4th (current) BATSE catalog (2494 objects)
is calculated. It is shown to be consistent with zero at nearly all angular
scales of interest. Assuming that GRBs trace the large scale structure in the
universe we calculate the angular correlation function for the standard CDM
(sCDM) model. It is shown to be at if the
BATSE catalog is assumed to be a volume-limited sample up to .
Combined with the error analysis on the BATSE catalog this suggests that nearly
GRBs will be needed to make a positive detection of the two-point
angular correlation function at this angular scale.Comment: 5 pages, Latex with aipproc.sty, incl. 1 ps-Fig., Proc. of the 5th
Huntsville Gamma Ray Burst Symposium, Oct. 1999, ed. R.M. Kippen, AI
Luminosity Function of GRBs
We attempt to constrain the luminosity function of Gamma Ray Bursts (GRBs) from the observed number count--flux relation and the afterglow redshift data. We assume three classes of luminosity functions for our analysis: (a) Log-normal distribution, (b) Schechter distribution, and (c) Scale-free distribution. We assume several models of the evolution of the GRB population for each luminosity function. Our analysis shows that: (a) log-normal is the only luminosity function that is compatible with both the observations. This result is independent of the GRB evolution model, (b) for log-normal function, the average photon luminosity and the width of the luminosity function that are compatible with both the observations fall in the range: 10^{55} sec^{-1} \la L_0 \la 10^{56} sec^{-1} and 2 \la \sigma \la 3, (c) the agreement of observations with other luminosity functions requires the GRB population to evolve more strongly than the evolution of the star-formation rate of the universe
ANTIDIABETIC EFFECT AND PHYTOCHEMICAL SCREENING OF ETHANOLIC EXTRACT OF POLYALTHIA CERASOIDES STEM BARK IN STREPTOZOTOCIN INDUCED DIABETIC ALBINO RATS
Objective: Polyalthia cerasoides stem bark is used in treatment the of various diseases. Some tribes of North Orissa used the stem bark in the treatment of diabetes. We investigated the effect of four different solvent (n-hexane, ethyl acetate, ethanol and aqueous) extracts of Polyalthia cerasoides stem bark on streptozotocintozocin (STZ) 45 mg/kg b. wt. induced diabetic rats.Methods: Normal control and diabetic control groups were allowed with free access to water throughout the experiment. Oral administration of four different solvent (n-hexane, ethyl acetate, ethanol and aqueous extracts of P. cerasoides stem bark to 12 hrs fasted normal and STZ induced diabetic rats at a dose of 200, 400 and 600 mg/kg b. wt for acute studies. (Determination of effective extract and dose: Â Each group was maintained with six rats)The fasting blood glucose FBG levels were checked for every 2 hrs (1h, 3h, 5h & 7h). Chronic study: Â (Each group was maintained with six rats)The normal and diabetic groups were supplemented with optimum dosage 400mg ethanol extract of P. cerasoides (PcEE) stem bark and 20 mg of glibinclamide (Glb) a standard drug treated diabetic group for 21 days.Results: Acute administration of P. cerasoides stem bark reduced FBG[A1]Â levels in ethanol extract atthe dosee 400 and 600 mg/ kg b. wt (48.5% and 32.4%, P<0.05) in the diabetic rats only. It does not affect the normal FBG levels in normal rats. In chronic treatment significant reduction in FBG levels in diabetic rats (51.6%). Body weight also increased in extract treated animals. The maximal antidiabetic effect was obtained in 400 mg PcEE[A2]Â which was similar to Glb treated group. The PcEE treated diabetic rats also confirmed the significant recovery of liver and kidney destruction.Conclusion: Our study has revealed the therapeutic effect of PcEE for diabetes and its related complications.Â
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
A CONTEMPORARY TECHNIQUE FOR LUNG DISEASE PREDICTION USING AND DL AND ML
Lung cancer is one of the major causes of cancer-related deaths due to its aggressive nature and delayed detections at advanced stages. Early detection of lung cancer is very important for the survival of an individual, and is a significant challenging problem. Generally, chest radiographs (X-ray) and computed tomography (CT) scans are used initially for the diagnosis of the malignant nodules; however, the possible existence of benign nodules leads to erroneous decisions. At early stages, the benign and the malignant nodules show very close resemblance to each other. In this paper, a novel deep learning-based model with multiple strategies is proposed for the precise diagnosis of the malignant nodules. Due to the recent achievements of deep convolutional neural networks (CNN) in image analysis, we have used two deep three-dimensional (3D) customized mixed link network (CMixNet) architectures for lung nodule detection and classification, respectively. Nodule detections were performed through faster R-CNN on efficiently-learned features from CMixNet and U-Net like encoder–decoder architecture. Classification of the nodules was performed through a gradient boosting machine (GBM) on the learned features from the designed 3D CMixNet structure. To reduce false positives and misdiagnosis results due to different types of errors, the final decision was performed in connection with physiological symptoms and clinical biomarkers. With the advent of the internet of things (IoT) and electro-medical technology, wireless body area networks (WBANs) provide continuous monitoring of patients, which helps in diagnosis of chronic diseases—especially metastatic cancers. The deep learning model for nodules’ detection and classification, combined with clinical factors, helps in the reduction of misdiagnosis and false positive (FP) results in early-stage lung cancer diagnosis. The proposed system was evaluated on LIDC-IDRI datasets in the form of sensitivity (94%) and specificity (91%), and better results were obatined compared to the existing method
RECENT PROGRESS OF DENDRIMERS IN DRUG DELIVERY FOR CANCER THERAPY
With the recent advances of nanotechnology, dendrimers are emerging as a highly attractive class of drug delivery vectors for cancer therapy. Dendrimers are multifunctional smart Nanocarriers to deliver one or more therapeutic agent safely and selectively to cancer cells. The high level of control over the synthesis of dendritic architecture makes dendrimers a nearly perfect (spherical) nanocarrier for site-specific drug delivery. The presence of functional groups in the dendrimers exterior also permits the addition of other moieties that can actively target certain diseases which are now widely used as tumor targeting strategies. Drug encapsulation, solubilization and passive targeting also equally contribute to the therapeutic use of dendrimers. Dendrimers are ideal carrier vehicles on cytotoxicity, blood plasma retention time, biodistribution and tumor uptake. In this review we highlight the advantages of dendrimers over conventional chemotherapy, toxicity and its management, following anti-cancer drugs delivered by using dendrimers and recent advances in drug delivery by various types of dendrimers as well as its diagnostic applications
Searching for GRB remnants in nearby galaxies
Gamma Ray Bursts (GRBs) are expected to leave behind GRB remnants, similar to
how ``standard'' supernovae (SN) leave behind SN remnants. The identification
of these remnants in our own and in nearby galaxies would allow a much closer
look at GRB birth sites, and possibly lead to the discovery of the compact
object left behind. It would also provide independent constraints on GRB rates
and energetics. We have initiated an observational program to search for GRB
remnants in nearby galaxies. The identification is based on specific line
ratios, such as OIII/ and HeII/, which are expected to be
unusually high in case of GRB remnants according to the theoretical predictions
of Perna et al. (2000). The observing strategies and preliminary studies from a
test run at 2.34 m VBT as well as archival data from planetary nebulae surveys
of spiral galaxies are discussed.Comment: 4 pages, uses aipproc.cls To appear in AIP, proceeding of GRB
conference '30 years after the discovery' held at Santa Fe, NM from 8-12
Sept, 200
ANALYSIS OF MOMENT ALGORITHMS FOR BLURRED IMAGES
with the remarkable growth in image processing, the requirements for dealing out with blurred images is difficulty in a variety of image processing applications. In this paper presents the restoration of blurred images which gets degraded due to diverse atmospheric and environmental conditions, Blur is a key determinant in the sensitivity of image quality, so it is essential to restore the original image.The research outcomes exhibit the major identified bottleneck for restoration is to deal with the blurred images and also a set of attempts have been executed in image restoration using multiple moment algorithms. However the precise results are not been proposed and demonstrated in the comparable researches. Also detail understanding for applications of moment algorithms for image restoration and demonstrating most suitable moment method is current requirements for research. Hence in this work we employ most accepted moment algorithms to exhibit the effect of moments for image restoration and the performance of the moment algorithms such as the Hu, Zernike and Legendre moments is evaluated on image with different blurring lengths. Moreover the effect of moment algorithms is also demonstrated in order to find the optimal setting of orders for image restoration. The final outcome of this work is a stable version of MATLAB based application to visually demonstrate the performance difference of Hu, Zernike and Legendre moments. The relative performance of the application is also been demonstrated with the help of multiple image datasets of biometric identifier such as fingerprint, hand palm and human face
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