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Phoolan Prasad 《Resonance》1997,2(7):8-19
In part 1 of this series we explained the concept of genuine nonlinearity, which is responsible for the appearance of discontinuities in a solution which was initially smooth. To include discontinuities in the solution, it became necessary to consider the governing equation in the form of a conservation law. In this part we first discuss an example of a continuous solution satisfying discontinuous initial data. Then we use the stability consideration to fix a unique solution of the conservation law. In the end, we present three examples which show that genuine nonlinearity significantly changes the evolution of the shape of a pulse. Continuous Solution with Discontinuous Initial Data 相似文献
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Hari Prasad 《Resonance》2002,7(12):48-64
Berzelius, the Swedish chemist in 1807 introduced the term ‘organic compounds’ as those substances derived from once living
organisms (organized systems). Carbon exhibits the property of catenation (formation of chains) and forms a plethora of compounds
on earth. Silicon on the other hand which is placed below carbon in the periodic table does not exhibit this property. This
article is a brief account of some of the several reagents and classes of compounds encountered in organosilicon chemistry. 相似文献
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Prasad P. Torkadi I. C. Apte A. K. Bhute 《Indian journal of clinical biochemistry : IJCB》2014,29(1):79-83
Alcoholic liver disease (ALD) is due to excessive alcohol intake for long duration. Distinguishing ALD from non-ALD (non-alcoholic steatohepatitis, hepatitis of viral origin) is difficult as patient may deny alcohol abuse. Clinical examination, histology and serology may not differentiate these conditions. Accurate diagnosis is important as management of ALD differs from non-ALD patients. The aim of our study was (1) To evaluate the patients of ALD and non-ALD by biochemical parameters compared to controls, (2) To assess whether these parameters can differentiate ALD from non-ALD. Study was carried out on 50 patients of ALD in group I and 35 patients of NASH (non-alcoholic steatohepatitis) and acute viral hepatitis each in group II. Age matched healthy controls n = 50. Selection criteria—history of alcohol intake (amount and duration), clinical examination, sonography of abdomen, serum alanine transaminase (ALT) and bilirubin levels. Blood samples were analyzed for bilirubin, aspartate transaminase (AST), ALT, alkaline phosphatase (ALP), gamma glutamyl transferase (GGT) by kinetic method. Statistical analysis was done by Student unpaired ‘t’ test. Patients of ALD have raised AST/ALT ratio (De Ritis ratio) (>2), ALP and GGT compared to controls (P < 0.01).There is significant difference in AST/ALT ratio, serum GGT and ALP in ALD group compared to that in NASH and acute viral hepatitis (P < 0.05). This study suggests that De Ritis ratio >2 in ALD patients may be due to alcohol induced hepatic mitochondrial injury and pyridoxine deficiency. High GGT and ALP values may indicate enzyme induction by alcohol and mild cholestasis. Thus ALD patients have severe hepatic damage. De Ritis ratio <1 and normal to mild elevation in GGT level in NASH and acute viral hepatitis suggest mild hepatic injury of non-alcoholic origin. Our study concludes that ALD patients can be differentiated from NASH and acute viral hepatitis with certainty by measuring serum AST/ALT ratio, GGT and ALP. These biochemical parameters may help clinicians to support the diagnosis of ALD and non-ALD. 相似文献
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Vandana Dixit Ashok V. Kurup A K Gupta O M Kataria G B K S Prasad 《Indian journal of clinical biochemistry : IJCB》1997,12(1):39-43
Lymphatic filariasis caused byWuchereria bancrofti is a major health problem next only to malaria. A study had been conducted to estimate the prevalence of microfilaraemia in a rural endemic community near Raipur. The incidence of microfilaramia in the community was found to be about 14% when studied by night finger prick method. The incidence appears to be more in males as compared to females. The infection rate in vector population i.e.,Culex quinquefasciatus was recorded at a rate of 10%. No relationship could be drawn between the rates of vector and human filarial infections or between the density of vector population and the rate of vector/human infection(s). Prior health education is essential before taking up control and preventive measures in given endemic zone. 相似文献
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Kiran?SarvabhotlaEmail author Prasad?Pingali Vasudeva?Varma 《Information Retrieval》2011,14(3):337-353
With the growth of social media, document sentiment classification has become an active area of research in this decade. It
can be viewed as a special case of topical classification applied only to subjective portions of a document (sources of sentiment).
Hence, the key task in document sentiment classification is extracting subjectivity. Existing approaches to extract subjectivity
rely heavily on linguistic resources such as sentiment lexicons and complex supervised patterns based on part-of-speech (POS)
information. This makes the task of subjective feature extraction complex and resource dependent. In this work, we try to
minimize the dependency on linguistic resources in sentiment classification. We propose a simple and statistical methodology
called review summary (RSUMM) and use it in combination with well-known feature selection methods to extract subjectivity.
Our experimental results on a movie review dataset prove the effectiveness of the proposed methodology. 相似文献
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A General Evaluation Framework for Topical Crawlers 总被引：10，自引：0，他引：10
Topical crawlers are becoming important tools to support applications such as specialized Web portals, online searching, and competitive intelligence. As the Web mining field matures, the disparate crawling strategies proposed in the literature will have to be evaluated and compared on common tasks through well-defined performance measures. This paper presents a general framework to evaluate topical crawlers. We identify a class of tasks that model crawling applications of different nature and difficulty. We then introduce a set of performance measures for fair comparative evaluations of crawlers along several dimensions including generalized notions of precision, recall, and efficiency that are appropriate and practical for the Web. The framework relies on independent relevance judgements compiled by human editors and available from public directories. Two sources of evidence are proposed to assess crawled pages, capturing different relevance criteria. Finally we introduce a set of topic characterizations to analyze the variability in crawling effectiveness across topics. The proposed evaluation framework synthesizes a number of methodologies in the topical crawlers literature and many lessons learned from several studies conducted by our group. The general framework is described in detail and then illustrated in practice by a case study that evaluates four public crawling algorithms. We found that the proposed framework is effective at evaluating, comparing, differentiating and interpreting the performance of the four crawlers. For example, we found the IS crawler to be most sensitive to the popularity of topics.Partially supported by National Science Foundation CAREER grant No. IIS-0133124/0348940. 相似文献
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In previous studies, we have reported first in vivo evidence of copper deposition in the choroid plexus, cognitive impairments, astrocytes swelling (Alzheimer type II cells) and astrogliosis (increase in number of astrocytes), and degenerated neurons coupled with significant increase in the hippocampus copper and zinc content in copper-intoxicated Wistar rats. Nonetheless, hippocampus iron levels were not affected by chronic copper-intoxication. Notwithstanding information on distribution of copper, zinc and iron status in different regions of brain due to chronic copper exposure remains fragmentary. In continuation with our previous study, the aim of this study was to investigate the effects of intraperitoneally injected copper lactate (0.15 mg Cu/100 g body weight) daily for 90 days on copper, zinc and iron levels in different regions of the brain using atomic absorption spectrophotometry. Copper-intoxicated group showed significantly increased cortex, cerebellum and striatum copper content (76, 46.8 and 80.7 % increase, respectively) compared to control group. However, non-significant changes were observed for the zinc and iron content in cortex, cerebellum and striatum due to chronic copper exposure. In conclusion, the current study demonstrates that chronic copper toxicity causes differential copper buildup in cortex, cerebellum and striatum region of central nervous system of male Wistar rats; signifying the critical requirement to discretely evaluate the effect of copper neurotoxicity in different brain regions, and ensuing neuropathological and cognitive dysfunctions. 相似文献