7,819 research outputs found

    A general purpose subroutine for fast fourier transform on a distributed memory parallel machine

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    One issue which is central in developing a general purpose Fast Fourier Transform (FFT) subroutine on a distributed memory parallel machine is the data distribution. It is possible that different users would like to use the FFT routine with different data distributions. Thus, there is a need to design FFT schemes on distributed memory parallel machines which can support a variety of data distributions. An FFT implementation on a distributed memory parallel machine which works for a number of data distributions commonly encountered in scientific applications is presented. The problem of rearranging the data after computing the FFT is also addressed. The performance of the implementation on a distributed memory parallel machine Intel iPSC/860 is evaluated

    Mathematical Modelling of Different Types of Body Support Surface for Pressure Ulcer Prevention

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    Pressure ulcer is a common problem for today’s healthcare industry. It occurs due to external load applied to the skin. Also when the subject is immobile for a longer period of time and there is continuous load applied to a particular area of human body, blood flow gets reduced and as a result pressure ulcer develops. Body support surface has a significant role in preventing ulceration so it is important to know the characteristics of support surface under loading conditions. In this paper we have presented mathematical models of different types of viscoelastic materials and also we have shown the validation of our simulation results with experiments

    A Review on Pressure Ulcer: Aetiology, Cost, Detection and Prevention Systems

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    Pressure ulcer (also known as pressure sore, bedsore, ischemia, decubitus ulcer) is a global challenge for today’s healthcare society. Found in several locations in the human body such as the sacrum, heel, back of the head, shoulder, knee caps, it occurs when soft tissues are under continuous loading and a subject’s mobility is restricted (bedbound/chair bound). Blood flow in soft tissues becomes insufficient leading to tissue necrosis (cell death) and pressure ulcer. The subject’s physiological parameters (age, body mass index) and types of body support surface materials (mattress) are also factors in the formation of pressure ulcer. The economic impacts of these are huge, and the subject’s quality of life is reduced in many ways. There are several methods of detecting and preventing ulceration in human body. Detection depends on assessing local pressure on tissue and prevention on scales of risk used to assess a subject prior to admission. There are also various types of mattresses (air cushioned/liquid filled/foam) available to prevent ulceration. But, despite this work, pressure ulcers remain common.This article reviews the aetiology, cost, detection and prevention of these ulcers

    An extinct vertebrate preserved by its living hybridogenetic descendant.

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    Hybridogenesis is a special mode of hybrid reproduction where one parental genome is eliminated and the other is transmitted clonally. We propose that this mechanism can perpetuate the genome of extinct species, based on new genetic data from Pelophylax water frogs. We characterized the genetic makeup of Italian hybridogenetic hybrids (P. kl. hispanicus and esculentus) and identified a new endemic lineage of Eastern-Mediterranean origin as one parental ancestor of P. kl. hispanicus. This taxon is nowadays extinct in the wild but its germline subsists through its hybridogenetic descendant, which can thus be considered as a "semi living fossil". Such rare situation calls for realistic efforts of de-extinction through selective breeding without genetic engineering, and fuels the topical controversy of reviving long extinct species. "Ghost" species hidden by taxa of hybrid origin may be more frequent than suspected in vertebrate groups that experienced a strong history of hybridization and semi-sexual reproduction

    Anastomosis grouping and genetic diversity analysis of Rhizoctonia solani isolates causing wet root rot in chickpea

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    Rhizoctonia solani is considered as one of the most destructive soil-and-seed borne plant pathogens infecting various agricultural crops including chickpea. The 50 chickpea isolates of R. solani representing 10 different states of India were variable in hyphal anastomosis reactions and they were grouped into seven AGs as AG1, AG2-2, AG2-2LP, AG2-3, AG3, AG4 and AG5. Genetic diversity of the pathogen was determined by using molecular markers namely, simple sequence repeats (SSR) and rDNA internal transcribed spacer (ITS). A neighbor-joining tree constructed based on the profiles generated by SSR markers grouped the isolates into eight categories. This revealed 90% of genetic similarity among the isolates and partial correlation with reference to their geographical origin and AGs. The isolates were amplified with a set of primers ITS 1 and ITS 4 and they produced a specific band ≈650 bp. Low level of (7%) variability was observed in the nucleotide sequences of the ITS regions of these isolates. The phylogenic tree generated from bootstrap neighboring joint analysis grouped the Indian populations of R. solani into two categories.Keywords: Chickpea, wet root rot, genetic diversity, simple sequence repeats (SSR), internal transcribed spacer (ITS)

    Study of CMEs Associated Intense Geomagnetic Storms Observed During Solar Maximum 1989-1991

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    Characterisation and neutralisation of Aeromonas hydrophila enterotoxin in the rabbit ileal-loop model

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    Cell-free culture filtrates and crude enterotoxin preparations from six strains of Aeromonas hydrophiza caused the accumulation of fluid in rabbit ileal loops. This activity was due to a non-dialysable, heat and acid-labile antigenic protein and was lost when culture filtrates and crude enterotoxin preparations were heated at 60°C for 20 min. or 56°C for 30 min. respectively. Maximum activity was observed at pH 8.0-10.0; there was a gradual loss at lower pH and activity was abolished in culture filtrates held at pH 3.0 and crude enterotoxin preparations held at pH 4.0. Titration of the crude enterotoxin preparations in rabbit ileal loops showed that the ED50 (equivalent to 1 unit of toxin) was contained in 25 μg of protein; a logarithmic plot of the neutralisation coefficients against antiserum concentrations showed that one unit of antitoxin was contained in 42×10−4 ml of the antiserum
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