540 research outputs found

    Primal-Dual 2-Approximation Algorithm for the Monotonic Multiple Depot Heterogeneous Traveling Salesman Problem

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    We study a Multiple Depot Heterogeneous Traveling Salesman Problem (MDHTSP) where the cost of the traveling between any two targets depends on the type of the vehicle. The travel costs are assumed to be symmetric, satisfy the triangle inequality, and are monotonic, i.e., the travel costs between any two targets monotonically increases with the index of the vehicles. Exploiting the monotonic structure of the travel costs, we present a 2-approximation algorithm based on the primal-dual method

    Seasonal hand line fishery for yellowfin tuna at Colachel

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    In Tamil Nadu, the oceanic tunas like skipjack and yellowfin tuna are exploited mainly by multiday drift gill netters. However, in Colachel, Kanyakumari, there is a seasonal fishery targeting yellowfin tuna of medium size weighing around 30 kg, with hand lines that are operated from multiday trawlers. This is an additional income for both the fishermen and the trawl boat owners

    Early investigation on cryopreservation of Dendrobium sonia-28 using encapsulation-dehydration with modified Evan blue assay

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    This study was conducted to determine the potential of cryostoring and regenerating Dendrobium sonia-28 protocorm-like bodies (PLBs) using the encapsulation-dehydration technique. The parameters tested for this study included the PLB size range (1 to 2 and 3 to 4 mm), preculture using six different sucrose concentrations (0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 M) and encapsulation using three different sodium alginate concentrations (2.5, 3.0 and 3.5%). Based on initial trials, 1 to 2 mm PLBs that were precultured in 1.0 M sucrose were selected for further studies as they produced the best viability as indicated by the Evans blue (EB) staining method. Subsequently, the PLBs were subjected to a 30 min encapsulation experiment involving the three sodium alginate concentrations. Finally, the chlorophyll content and total soluble protein of cryopreserved, non-cryopreserved and untreated PLBs were determined.Key words: Orchid, protocorm-like bodies, cryopreservation

    A comparative assessment of the impact of computer assisted learning of knowledge and skill based competencies among undergraduate students in a medical college in South India

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    Background: Pharmacology has always been one subject ultimatum and a cornerstone in building up competency, based on applied therapeutics among medical graduates in prescribing and practicing skills. A focus on an integrated strategical approach towards teaching pharmacology for better proficiency in achieving clinical skills is mandatory. Thus, this study has been done to assess the impact and retainment of overall knowledge gained on various domains, based on a revised method of teaching in pharmacology.Methods: An observational, questionnaire based comparative study was done in a medical college, in Chennai. The study included two group of students, one who have completed their pharmacology course based on the revised pattern of teaching with a comparative group of students who have not been exposed to the revised pattern of teaching. A feedback survey was also done.Results: The study results indicated that the average scoring based on the questionnaire was 84% with the students who have been exposed to revised pattern of teaching in comparison to the average scoring of 70% with the students who have not been exposed to the new pattern of teaching. The average scoring of the students who were found to agree to several questions on the new method of teaching was 74% and 22% of the students were found to disagree. 4% of students were non responders.Conclusions: The ultimate improvement in the outcome of health care education can be achieved through appropriate skill building through a simple strategical modification of the regular teaching pattern with an integrated approach involving pharmacologists and clinicians. A refresher course in pharmacology in the final year curriculum and CRRI involving pharmacologists is mandatory

    The effects of intrinsic noise on the behaviour of bistable cell regulatory systems under quasi-steady state conditions

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    We analyse the effect of intrinsic fluctuations on the properties of bistable stochastic systems with time scale separation operating under1 quasi-steady state conditions. We first formulate a stochastic generalisation of the quasi-steady state approximation based on the semi-classical approximation of the partial differential equation for the generating function associated with the Chemical Master Equation. Such approximation proceeds by optimising an action functional whose associated set of Euler-Lagrange (Hamilton) equations provide the most likely fluctuation path. We show that, under appropriate conditions granting time scale separation, the Hamiltonian can be re-scaled so that the set of Hamilton equations splits up into slow and fast variables, whereby the quasi-steady state approximation can be applied. We analyse two particular examples of systems whose mean-field limit has been shown to exhibit bi-stability: an enzyme-catalysed system of two mutually-inhibitory proteins and a gene regulatory circuit with self-activation. Our theory establishes that the number of molecules of the conserved species are order parameters whose variation regulates bistable behaviour in the associated systems beyond the predictions of the mean-field theory. This prediction is fully confirmed by direct numerical simulations using the stochastic simulation algorithm. This result allows us to propose strategies whereby, by varying the number of molecules of the three conserved chemical species, cell properties associated to bistable behaviour (phenotype, cell-cycle status, etc.) can be controlled.Comment: 33 pages, 9 figures, accepted for publication in the Journal of Chemical Physic

    Multiple factors interact to produce responses resembling spectrum of human disease in Campylobacter jejuni infected C57BL/6 IL-10-/- mice

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    <p>Abstract</p> <p>Background</p> <p><it>Campylobacter jejuni </it>infection produces a spectrum of clinical presentations in humans – including asymptomatic carriage, watery diarrhea, and bloody diarrhea – and has been epidemiologically associated with subsequent autoimmune neuropathies. This microorganism is genetically variable and possesses genetic mechanisms that may contribute to variability in nature. However, relationships between genetic variation in the pathogen and variation in disease manifestation in the host are not understood. We took a comparative experimental approach to explore differences among different <it>C. jejuni </it>strains and studied the effect of diet on disease manifestation in an interleukin-10 deficient mouse model.</p> <p>Results</p> <p>In the comparative study, C57BL/6 interleukin-10<sup>-/- </sup>mice were infected with seven genetically distinct <it>C. jejuni </it>strains. Four strains colonized the mice and caused disease; one colonized with no disease; two did not colonize. A DNA:DNA microarray comparison of the strain that colonized mice without disease to <it>C. jejuni </it>11168 that caused disease revealed that putative virulence determinants, including loci encoding surface structures known to be involved in <it>C. jejuni </it>pathogenesis, differed from or were absent in the strain that did not cause disease. In the experimental study, the five colonizing strains were passaged four times in mice. For three strains, serial passage produced increased incidence and degree of pathology and decreased time to develop pathology; disease shifted from watery to bloody diarrhea. Mice kept on an ~6% fat diet or switched from an ~12% fat diet to an ~6% fat diet just before infection with a non-adapted strain also exhibited increased incidence and severity of disease and decreased time to develop disease, although the effects of diet were only statistically significant in one experiment.</p> <p>Conclusion</p> <p><it>C. jejuni </it>strain genetic background and adaptation of the strain to the host by serial passage contribute to differences in disease manifestations of <it>C. jejuni </it>infection in C57BL/6 IL-10<sup>-/- </sup>mice; differences in environmental factors such as diet may also affect disease manifestation. These results in mice reflect the spectrum of clinical presentations of <it>C. jejuni </it>gastroenteritis in humans and contribute to usefulness of the model in studying human disease.</p

    Three-dimensional anatomical accuracy of cranial models created by rapid prototyping techniques validated using a neuronavigation station

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    In neurosurgery and ear, nose and throat surgery the application of computerised navigation systems for guiding operations has been expanding rapidly. However, suitable models to train surgeons in using navigation systems are not yet available. We have developed a technique using an industrial, rapid prototyping process from which accurate spatial models of the cranium, its contents and pathology can be reproduced for teaching. We were able to register, validate and navigate using these models with common available navigation systems such as the Medtronic StealthStation S7 (R). (C) 2011 Elsevier Ltd. All rights reserved. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down

    Lung volume reduction surgery versus endobronchial valves: a randomised controlled trial

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    BACKGROUND: Lung volume reduction surgery (LVRS) and bronchoscopic lung volume reduction (BLVR) with endobronchial valves can improve outcomes in appropriately selected patients with emphysema. However, no direct comparison data exist to inform clinical decision making in people who appear suitable for both procedures. Our aim was to investigate whether LVRS produces superior health outcomes when compared with BLVR at 12 months. METHODS: This multicentre, single-blind, parallel-group trial randomised patients from five UK hospitals, who were suitable for a targeted lung volume reduction procedure, to either LVRS or BLVR and compared outcomes at 1 year using the i-BODE score. This composite disease severity measure includes body mass index, airflow obstruction, dyspnoea and exercise capacity (incremental shuttle walk test). The researchers responsible for collecting outcomes were masked to treatment allocation. All outcomes were assessed in the intention-to-treat population. RESULTS: 88 participants (48% female, mean±sd age 64.6±7.7 years, forced expiratory volume in 1 s percent predicted 31.0±7.9%) were recruited at five specialist centres across the UK and randomised to either LVRS (n=41) or BLVR (n=47). At 12 months follow-up, the complete i-BODE was available in 49 participants (21 LVRS/28 BLVR). Neither improvement in the i-BODE score (LVRS -1.10±1.44 versus BLVR -0.82±1.61; p=0.54) nor in its individual components differed between groups. Both treatments produced similar improvements in gas trapping (residual volume percent predicted: LVRS -36.1% (95% CI -54.6- -10%) versus BLVR -30.1% (95% CI -53.7- -9%); p=0.81). There was one death in each treatment arm. CONCLUSION: Our findings do not support the hypothesis that LVRS is a substantially superior treatment to BLVR in individuals who are suitable for both treatments
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