372 research outputs found

    Evolutionary dynamics on strongly correlated fitness landscapes

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    We study the evolutionary dynamics of a maladapted population of self-replicating sequences on strongly correlated fitness landscapes. Each sequence is assumed to be composed of blocks of equal length and its fitness is given by a linear combination of four independent block fitnesses. A mutation affects the fitness contribution of a single block leaving the other blocks unchanged and hence inducing correlations between the parent and mutant fitness. On such strongly correlated fitness landscapes, we calculate the dynamical properties like the number of jumps in the most populated sequence and the temporal distribution of the last jump which is shown to exhibit a inverse square dependence as in evolution on uncorrelated fitness landscapes. We also obtain exact results for the distribution of records and extremes for correlated random variables

    The Effect of Geometry Changes on Sliding-Block Predictions

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    The sliding-block model is often used for the prediction of permanent co-seismic displacements of slopes and earth structures. This model assumes motion in an inclined plane but does not consider the decrease in inclination of the sliding soil mass as a result of its downward motion, which is the usual state in the field. The paper studies the above effect and proposes an empirical equation correcting the predictions of the sliding-block model. The investigation is performed using the recently-developed multi-block model

    Some Chelates of Al(III) & Their Reactions

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    408-40

    RANITIDINE CONTROLLED RELEASE ANTI-REFLUX SUSPENSION FOR GASTRO-OESOPHAGEAL REFLUX DISEASE AND IT’S IN VITRO EVALUATION

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    Objective: The aim of this work was to develop triple action controlled release anti-reflux suspension of ranitidine and its in-vitro evaluation of anti-reflux and controlled release properties. Methods: The formulation was optimized using sodium alginate as a gelling agent along with calcium carbonate, sodium bicarbonate, magnesium hydroxide, aluminium hydroxide as alkalizing agents and colloidal microcrystalline cellulose (MCC) as a suspending agent at various concentrations and arrived at an optimized formulation for its best quality attributes. To avoid initial release in water before administration, ranitidine coated MCC sphere was incorporated into powder formulation and subjected to in vitro characteristics like raft strength, acid neutralizing capacity, pH, viscosity and dissolution study. The obtained results were assessed using Minitab 17 statistical software to conclude the study design. Results: Formulation containing 300 mg of ranitidine along with 750 mg alginate has shown better anti-reflux characteristics like raft strength 18±2g, acid neutralizing capacity 17±1 mEq compared to other formulations. This formulation has also shows zero-order controlled release in the simulated gastric fluid (SGF) up to 10 h compared to the formulation without alginate. Further, to this optimized formulation has shown negligible change in the assay of ranitidine even after 3 mo at 40 °C temperature and 75% RH. Conclusion: The developed stable sustained release powder for suspension has the combined therapeutic efficacy as an antacid and anti-reflux drug suitable for the management and treatment of gastro-oesophageal reflux disease (GERD) unlike the existing drugs possessing only reflux resistance action

    Pod set and Pollen Viability Studies in Yard Long Bean (Vigna unguiculata sub sp. sesquipedalis)

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    A study was conducted in a yard long bean (Vigna unguiculata sup/ssp. sesquipedalis) hybrid VS 50 (Kakkamoola Local) x VS 26 (Vellayani Jyothika) to assess the percentage fruit set at two time intervals and to identify the best time interval for pollination in yard long bean hybrids. Hand pollination was done using VS 50 as female parent and VS 26 as male parent for seven consecutive days at two time intervals, 6.30 – 7.30 am and 7.30 – 8.30 am. Higher percentage of fruit set (36.8 %) was observed between 6:30 – 7:30 a.m. as compared to the time interval 7:30 – 8:30 am. (23.8%). Pollen viability was determined for the parents VS 50 (Kakkamoola Local) and VS 26 (Vellayani Jyothika) at 6.30, 7.30 and 8.30 am. Highest pollen viability for both the parents VS 50 and VS 26 was observed during 7.30 am. The present study shows that the best time interval for crossing in yard long bean is 6.30- 7.30 a.m

    Toward integrated conservation of North America's crop wild relatives

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    North America harbors a rich native flora of crop wild relatives—the progenitors and closely related species of domesticated plants—as well as a range of culturally significant wild utilized plants. Despite their current and potential future value, they are rarely prioritized for conservation efforts; thus many species are threatened in their natural habitats, and most are underrepresented in plant genebanks and botanical gardens. Further coordination of efforts among land management, botanical, and agricultural science organizations will improve conservation and general public awareness with regard to these species. We present examples of productive collaborations focused on wild cranberries (Vaccinium macrocarpon and Vaccinium oxycoccos) and chile peppers (Capsicum annuum var. glabriusculum). We then discuss five shared priorities for further action: (1) understand and document North America's crop wild relatives and wild utilized plants, (2) protect threatened species in their natural habitats, (3) collect and conserve ex situ the diversity of prioritized species, (4) make this diversity accessible and attractive for plant breeding, research, and education, and (5) raise public awareness of their value and the threats to their persistence

    Measuring Decentrality in Blockchain Based Systems

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    Blockchain promises to provide a distributed and decentralized means of trust among untrusted users. However, in recent years, a shift from decentrality to centrality has been observed in the most accepted Blockchain system, i.e., Bitcoin. This shift has motivated researchers to identify the cause of decentrality, quantify decentrality and analyze the impact of decentrality. In this work, we take a holistic approach to identify and quantify decentrality in Blockchain based systems. First, we identify the emergence of centrality in three layers of Blockchain based systems, namely governance layer, network layer and storage layer. Then, we quantify decentrality in these layers using various metrics. At the governance layer, we measure decentrality in terms of fairness, entropy, Gini coefficient, Kullback-Leibler divergence, etc. Similarly, in the network layer, we measure decentrality by using degree centrality, betweenness centrality and closeness centrality. At the storage layer, we apply a distribution index to define centrality. Subsequently, we evaluate the decentrality in Bitcoin and Ethereum networks and discuss our observations. We noticed that, with time, both Bitcoin and Ethereum networks tend to behave like centralized systems where a few nodes govern the whole network

    Quality of life of alcohol dependent patients attending a deaddiction centre in Kannur district

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    Background: Quality of life (QOL) is individuals' perceptions of their position in life. QOL of alcohol dependent patients is an area that has received relatively less attention compared to other alcohol related problems.Methods: A deaddiction centre based cross sectional study was done on 370 individuals using a predesigned questionnaire during the period of 2012-2013. The data was analyzed using SPSS version 17. Spearman’s rank correlation test was used to find association between the study variables.Results: The mean age of the study subjects was 38.08±8.46 years. The mean duration of drinking was 12.62±7.47 years. The overall score of the QOL and the perceived health in alcohol dependent patients was 3.19±0.89 and 3.01±0.98 respectively. The mean of the transformed scores of physical, psychological, social and environmental domains are 69.12±12.82, 57.84±12.81, 58.52±17.05, 68.62±10.23 respectively. Statistical analysis of age with physical, environmental and social domains showed a significant negative correlation; literacy status with QOL, perceived health, physical, psychological, social and environmental domains showed a significant positive correlation; socio economic status with QOL and psychological domain showed a significant positive correlation; duration of drinking with QOL, perceived health, physical and psychological domain showed a significant negative correlation.Conclusions: Harm from alcohol use is a major public health problem. Reducing the level of social and health harms from alcohol requires preparation and planning
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