634 research outputs found
Effect of starvation on the biochemical composition of Clarias batrachus (Linn.)
Marked changes were observed in different chemical constituents of C. batrachus during starvation. The N and protein fractions showed a definite pattern of variations. The highest values of these were recorded on 10th day of starvation and thereafter values declined gradually. On the other hand, the acid soluble phosphorus exhibited a reverse trend, increasing gradually from the first to the 30th day of starvation. These changes have been attributed mainly to the energy and metabolic demands of the starving fish
Full and fast calibration of the Heston stochastic volatility model
This paper presents an algorithm for a complete and e cient calibration of the Heston stochastic volatility model. We express the calibration as a nonlinear least-squares problem. We exploit a suitable representation of the Heston characteristic function and modify it to avoid discontinuities caused by branch switchings of complex functions. Using this representation, we obtain the analytical gradient of the price of a vanilla option with respect to the model parameters, which is the key element of all variants of the objective function. The interdependency between the components of the gradient enables an e cient implementation which is around ten times faster than a numerical gradient. We choose the Levenberg-Marquardt method to calibrate the model and do not observe multiple local minima reported in previous research. Two-dimensional sections show that the objective function is shaped as a narrow valley with a flat bottom. Our method is the fastest calibration of the Heston model developed so far and meets the speed requirement of practical trading
Recommended from our members
Glucagon Secreting Tumors and Glucagonoma Syndrome
Glucagonomas are the functioning neuroendocrine tumors. These arise from pancreatic islet α-cells. These tumors are extremely rare and have an annual incidence of 1 per 20-40 million population 80% of glucagon-expressing tumors are sporadic, and 20% are associated with genetic syndromes such as Multiple Endocrine Neoplasia-type 1. Glucagonoma typically occurs in the distal pancreas, and around 85% are in the body or tail. It tends to be large at the time of diagnosis. Most reported cases of glucagonoma are malignant and about 65-75% patients present with metastatic disease. The liver is usually the first site of metastases, followed by the involvement of peripancreatic lymph nodes. The term Glucagonoma syndrome and glucagonoma are often interchangeably used, but in fact, these are two distinct entities. Glucagonoma syndrome comprises of necrolytic migratory erythema, hyperglucagonemia, diabetes mellitus, anemia, weight loss, glossitis, diarrhea, venous thrombosis and neuropsychiatric disturbances in the presence of a glucagon-producing tumor of the pancreas. Tumors secreting glucagon can occur without the glucagonoma syndrome. The glucagonoma secretion depends on the expression of protein convertase enzyme PC1/3 or PC2 within the tumor itself. As a result of this expression, the clinical manifestations can be variable. The tumor can either present with hyperinsulinemic hypoglycemia in a patient with a previous history of diabetes or with the features of the glucagonoma syndrome. In cases where a tumor is localized surgery is the curative treatment. Reduction of the tumor bulk, removal of the primary by surgery and targeted therapy for the hepatic metastases are the favored approach even when there is the metastasis
AN OVERALL VIEW ON GEMSTONE MINING IN GILGIT-BALTISTAN: PROBLEMS AND MITIGATIONS
Gilgit-Baltistan has tremendous amount of gemstone wealth and thousands of miners are busy to explore this wealth, but due to unscientific and crude mining methods this mineral wealth goes into waste in many ways, like fractures, damages and total destructions of gemstone due to ill blasting methods and lack of proper training. Gemstone mining is done in all districts of Gilgit-Baltistan. According to a careful survey in July 2007, 32 types of Gemstones (Precious and Semiprecious) are found in GB, out of total production of gemstones produced in Pakistan 95% come from GB. According to this survey there are more than 2000 mines which produce different variety of gemstones and numbers of miners involved in this mining industry directly or indirectly are more than 25000. Due to these crude and unscientific mining methods, improper camps without hygienic facilities, lack of proper mining equipment, lack of basic health facilities and safety tools and lack of mining equipment repairing facilities at mining sites, number of problems are arising. These problems include damage to the fauna and flora in mining areas, damage to the eco system due to blasting and flow of people; mountains are becoming vulnerable due to improper mines development, glaciers melting due to use of thermal generators, spreading of human filth and waste like plastic and at last polluting of the water. This research is based on the mitigation of all these problems to some extent. The damage to the fauna and flora may be reduced by controlling spreading of human filth and waste, controlled blasting may be done by using modern blasting techniques, proper mines of international standard may be developed by enforcing the mining rules, use of thermal generators may be prohibited by developing small hydro projects at sites and at last pollution of water may be controlled by training people to adopt the cleanliness drives time to time and equipment repairing facilities at sites as well.  
In silico CD4+, CD8+ & humoral immunity associated antigenic epitope prediction and HLA distribution analysis of HTLV-I
Purpose: The linkage of human T-cell leukemia virus type 1 (HTLV-1) to fatal diseases is a well known fact for many years. However, there has been no significant progress in the field of the treatment that can lead to the development of a successful vaccine. Furthermore, there are no means of assessing the risk of disease and its prognosis in the infected people.
Methods:The current study has taken the cognizance of the importance of hostâs immune response in reducing the risk of infectious diseases to carry out immunoinformatics driven epitope screening strategy of vaccine candidates against HTLV-1. In this study, a genetic variability and HLA distribution analysis among the documented HTLV-1 genotypes I, II, III, IV, V & VI was performed to ensure the coverage of the vast majority of population, where vaccine would be employed. The meticulous screening of effective dominant immunogens was done with the help of ABCPred and Immune Epitope Database.
Results: The results showed that the identified epitopes might be protective immunogens with high conservancy and potential of inducing both protective neutralizing antibodies and Tcell responses. The peptides âPSQLPPTAPPLLPHSNLDHIâ, âPCPNLVAYSSYHATYâ, and âYHATYSLYLFâ, were 100% conserved among different isolates from far and wide separated countries, suggesting negligible antigenic drift in HTLV-1.
Conclusions: Overall, the mentioned epitopes are soluble, non-toxic suitable candidates for the development of vaccine against HTLV-1 and warrant further investigation and experimental validation
Deep learning for detection and segmentation of artefact and disease instances in gastrointestinal endoscopy
The Endoscopy Computer Vision Challenge (EndoCV) is a crowd-sourcing initiative to address eminent problems in developing
reliable computer aided detection and diagnosis endoscopy systems and suggest a pathway for clinical translation
of technologies. Whilst endoscopy is a widely used diagnostic and treatment tool for hollow-organs, there are several core
challenges often faced by endoscopists, mainly: 1) presence of multi-class artefacts that hinder their visual interpretation, and
2) difficulty in identifying subtle precancerous precursors and cancer abnormalities. Artefacts often affect the robustness of
deep learning methods applied to the gastrointestinal tract organs as they can be confused with tissue of interest. EndoCV2020
challenges are designed to address research questions in these remits. In this paper, we present a summary of methods
developed by the top 17 teams and provide an objective comparison of state-of-the-art methods and methods designed by
the participants for two sub-challenges: i) artefact detection and segmentation (EAD2020), and ii) disease detection and
segmentation (EDD2020). Multi-center, multi-organ, multi-class, and multi-modal clinical endoscopy datasets were compiled
for both EAD2020 and EDD2020 sub-challenges. The out-of-sample generalization ability of detection algorithms was also
evaluated. Whilst most teams focused on accuracy improvements, only a few methods hold credibility for clinical usability. The
best performing teams provided solutions to tackle class imbalance, and variabilities in size, origin, modality and occurrences
by exploring data augmentation, data fusion, and optimal class thresholding techniques
Nosocomial acquisition of methicillin-resistant Staphyloccocus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL) Enterobacteriaceae in hospitalised patients: a prospective multicenter study
The risk of acquisition of antibiotic resistant-bacteria during or shortly after antibiotic therapy is still unclear and it is often confounded by scarce data on antibiotic usage.Primary objective of the study is to compare rates of acquisition of methicillin-resistant Staphylococcus aureus and extended spectrum beta-lactamase-producing Enterobacteriaceae in hospitalised patients, after starting antibiotic therapy
Fused 3-Hydroxy-3-trifluoromethylpyrazoles Inhibit Mutant Huntingtin Toxicity
[Image: see text] Here, we describe the selection and optimization of a chemical series active in both a full-length and a fragment-based Huntingtonâs disease (HD) assay. Twenty-four thousand small molecules were screened in a phenotypic HD assay, identifying a series of compounds bearing a 3-hydroxy-3-trifluoromethylpyrazole moiety as able to revert the toxicity induced by full-length mutant Htt by up to 50%. A chemical exploration around the series led to the identification of compound 4f, which demonstrated to be active in a Htt171â82Q rat primary striatal neuron assay and a PC12-Exon-1 based assay. This compound was selected for testing in R6/2 mice, in which it was well-tolerated and showed a positive effect on body weight and a positive trend in preventing ventricular volume enlargment. These studies provide strong rationale for further testing the potential benefits of 3-hydroxy-3-trifluoromethylpyrazoles in treating HD
- âŠ