1,170 research outputs found

    Lattices of hydrodynamically interacting flapping swimmers

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    Fish schools and bird flocks exhibit complex collective dynamics whose self-organization principles are largely unknown. The influence of hydrodynamics on such collectives has been relatively unexplored theoretically, in part due to the difficulty in modeling the temporally long-lived hydrodynamic interactions between many dynamic bodies. We address this through a novel discrete-time dynamical system (iterated map) that describes the hydrodynamic interactions between flapping swimmers arranged in one- and two-dimensional lattice formations. Our 1D results exhibit good agreement with previously published experimental data, in particular predicting the bistability of schooling states and new instabilities that can be probed in experimental settings. For 2D lattices, we determine the formations for which swimmers optimally benefit from hydrodynamic interactions. We thus obtain the following hierarchy: while a side-by-side single-row "phalanx" formation offers a small improvement over a solitary swimmer, 1D in-line and 2D rectangular lattice formations exhibit substantial improvements, with the 2D diamond lattice offering the largest hydrodynamic benefit. Generally, our self-consistent modeling framework may be broadly applicable to active systems in which the collective dynamics is primarily driven by a fluid-mediated memory

    Bacteriological profile and antibiogram of blood culture isolates from patients of rural tertiary care hospital

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    Microbial invasion of blood stream is associated with significant mortality and morbidity. Identification of bacterial isolates and antibiotic susceptibility of bacteria isolated from blood culture would guide the antibiotics treatment for patients with bacteremia. 1) To determine age – wise blood culture positivity rate in bacteremia 2) To identify age – wise common bacterial species isolates in bacteremia 3) To determine Antibiotic sensitivity pattern of the bacterial isolates. Atotal of 247 blood culture samples received from various clinical departments of rural teaching hospital from August 2013 to September 2015 were included in the study. Samples were collected in brain heart infusion broth. Identification of isolates and antimicrobial susceptibility was done as per standard microbiological methods. Out of 247 specimens bacteria sp. was isolated from 46 (18.62%) samples. Blood culture positivity was noted highest among neonates age group (38.71%). Lowest rate was observed among elders (4.55%). Klebsiella pneumoniae, Coagulase negative staphylococcus (CONs), and S. aureus were common blood culture isolates. In neonates Klebsiella pneumoniae was the most common isolate. Out of 27 gram negative bacilli, 14 (51.85%) were extended spectrum betalactamases (ESBL) positive. High resistance was noted against amoxycillin and amoxicillin/clavulanic acid and third generation cephalosporins in all gram negative organisms except, S. typhi. Out of 12 Staphylococcus sp., none of these were methicillin resistant. Routine antibiotic susceptibility surveillance helps in choice of antibiotics for treatment, identification of resistance and control of its spread. Published by the International journal of Microbiology and Mycology (IJMM

    Two phase detonation studies

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    An experimental study of the passage of a shock wave over a burning fuel drop is described. This includes high speed framing photographs of the interaction taken at 500,000 frames per second. A theoretical prediction of the ignition of a fuel drop by a shock wave is presented and the results compared with earlier experimental work. Experimental attempts to generate a detonation in a liquid fuel drop (kerosene)-liquid oxidizer drop (hydrogen peroxide)-inert gas-environment are described. An appendix is included which gives the analytical prediction of power requirements for the drop generator to produce certain size drops at a certain mass rate. A bibliography is also included which lists all of the publications resulting from this research grant

    Global citizenship education for whom? Indo-German reflections on glocal vignettes from worldwide practices

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    This commentary, by two authors from the Global North and Global South respectively, reflects on the significance of (auto)ethnographic vignettes as a point of departure for an emic approach, applying the concept of Global Citizenship Education (GCE) to the maxim of \u27education for all\u27 as promulgated by the UN from 1990. The authors explore GCE from a post- and decolonial perspective, with a particular focus on the universal right to education and the power structures, hierarchies, and misunderstandings that are reflected in or arise from subconscious assumptions or conventions. With a discussion of the global roots and discourses that have led to the emergence of GCE as a concept, the authors point to the complexities of GCE, which needs to combine global responsibility with knowledge about and respect for local traditions if it is to free itself from the imperial connotations of Enlightenment universalism. Ultimately, the authors conclude, in order to \u27learn\u27 GCE we must first \u27de-learn\u27 conventional (colonial) power relations. (DIPF/Orig.

    Linking the evolution of terrestrial interiors and an early outgassed atmosphere to astrophysical observations

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    A terrestrial planet is molten during formation and may remain so if subject to intense insolation or tidal forces. Observations continue to favour the detection and characterisation of hot planets, potentially with large outgassed atmospheres. We aim to determine the radius of hot Earth-like planets with large outgassed atmospheres and explore differences between molten and solid silicate planets and their influence on the mass-radius relationship and transmission and emission spectra. An interior-atmosphere model, combined with static structure calculations, tracks the evolving radius of a rocky mantle that is outgassing CO2_2 and H2_2O. Synthetic emission and transmission spectra are generated for CO2_2 and H2_2O dominated atmospheres. Atmospheres dominated by CO2_2 suppress the outgassing of H2_2O to a greater extent than previously realised, as previous studies have applied an erroneous relationship between volatile mass and partial pressure. We therefore predict more H2_2O can be retained by the interior during the later stages of magma ocean crystallisation. Furthermore, formation of a lid at the surface can tie outgassing of H2_2O to the efficiency of heat transport through the lid, rather than the atmosphere's radiative timescale. Contraction of the mantle as it solidifies gives 5%\sim5\% radius decrease, which can partly be offset by addition of a relatively light species to the atmosphere. We conclude that a molten silicate mantle can increase the radius of a terrestrial planet by around 5%5\% compared to its solid counterpart, or equivalently account for a 13%13\% decrease in bulk density. An outgassing atmosphere can perturb the total radius according to its speciation. Atmospheres of terrestrial planets around M-stars that are dominated by CO2_2 or H2_2O can be distinguished by observing facilities with extended wavelength coverage (e.g., JWST).Comment: 19 pages, published in A&A, abstract shortene

    Continuous Uniform Finite Time Stabilization of Planar Controllable Systems

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    Continuous homogeneous controllers are utilized in a full state feedback setting for the uniform finite time stabilization of a perturbed double integrator in the presence of uniformly decaying piecewise continuous disturbances. Semiglobal strong C1\mathcal{C}^1 Lyapunov functions are identified to establish uniform asymptotic stability of the closed-loop planar system. Uniform finite time stability is then proved by extending the homogeneity principle of discontinuous systems to the continuous case with uniformly decaying piecewise continuous nonhomogeneous disturbances. A finite upper bound on the settling time is also computed. The results extend the existing literature on homogeneity and finite time stability by both presenting uniform finite time stabilization and dealing with a broader class of nonhomogeneous disturbances for planar controllable systems while also proposing a new class of homogeneous continuous controllers

    The Measure of Success: Evaluating Corporate Citizenship Performance

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    This is the second publication resulting from the Measure of Success research project, designed to explore the current corporate perspective on and practices in measuring corporate citizenship performance. It presents a discussion of the evolution of corporate citizenship and how the political debates have influenced measurement practice; and a discussion of measurement as a management tool in the design and implementation of corporate citizenship programmes

    Formononetin Treatment in Type 2 Diabetic Rats Reduces Insulin Resistance and Hyperglycemia

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    Type 2 diabetic mellitus is a multifactorial metabolic disorder affecting huge population around the world. This indicates that there is an urgent unmet need of cost effective, new treatment strategies for type 2 diabetes mellitus with no or less side effects. Phenolic compounds including isoflavones are known for their beneficial effect in metabolic disorders. The present work was intended to find out efficacy of formononetin, an isoflavone treatment in experimental model of type 2 diabetes. Type 2 diabetes mellitus was induced by feeding high fat diet for 2 weeks prior to streptozotocin administration in Sprague Dawley rats. Diabetic animals were treated with formononetin for 28 days at three dose level, i.e., 10, 20, and 40 mg/kg body weight orally. The effect of formononetin treatment on various parameters such as plasma glucose, glucose tolerance, insulin, HOMA-IR, lipid profile, hepatic glycogen content, glycohaemoglobin and SIRT1 expression in pancreatic tissue was measured. Histopathological changes in pancreatic tissue were also studied. Results of the study demonstrate that formononetin treatment reduces blood glucose level significantly (p < 0.001) at all the three dose level. It also improved glucose tolerance, insulin sensitivity and lipid profile along with reduction in glycohaemoglobin content in blood. Formononetin treatment also improved hepatic glycogen level profoundly in diabetic rats. Determination of SIRT1 expression in pancreatic tissue by immunohistochemical analysis showed that formononetin treatment increases the expression of SIRT1 in pancreatic tissue. Histopathological study showed that treatment with formononetin protects pancreatic beta cells from necro-degeneration and atrophic effect. It can be concluded that formononetin treatment reduces insulin resistance and attenuate hyperglycemia in type 2 diabetes which may be due to increasing expression of SIRT1 in pancreatic tissues

    Role of yogic practices in individuals with hypertension and low-Peak Expiratory Flow Rate (PEFR) of Ahmedabad city

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    Hypertension is one of the most important risk factors for various heart related diseases in India, especially in South-Asian region. Nowadays because of very fast life style, breathing pattern and its duration is changed considerably. Breathing duration becomes very short. The main aim of the present study was to assess the therapeutic role of yoga on various cardiovascular parameters, peak expiratory flow rate (PEFR) through pulmonary function test and peripheral capillary oxygen saturation (SpO2), amount of oxygen in the blood in Ahmedabad population. Total 50 individuals with hypertension, low-PEFR and low-SpO2 were selected for the present study. All participants were subjected to yoga therapy (pranayama, yoga postures and meditation) for various time intervals of 0, 3, 6, 9, and 12 months. Heart rate (HR), systolic pressure (SP), diastolic pressure (DP), pulse pressure (PP), mean arterial pressure (MAP), rate pressure product (RPP), double product (DoP), PEFR and SpO2 were measured from all individuals at different intervals. At 0 month, all individuals had very high heart rate (HR), systolic pressure (SP), diastolic pressure (DP), pulse pressure (PP), mean arterial pressure (MAP), rate pressure product (RPP), double product (DoP), but PEFR and SpO2 levels were very low. At the end of 12 month of yoga intervention, significant decrease in all cardiovascular parameters whereas significant elevation of PEFR and SpO2 levels were observed. In conclusion, a comprehensive yoga therapy programme has immense potential to augment the beneficial effects of standard medical management of hypertension, lungs function and total oxygen concentration. Hence it can be used as an effective complementary therapy for heart related diseases
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