2,897 research outputs found

    Risk-based framework for SLA violation abatement from the cloud service provider's perspective

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    © The British Computer Society 2018. The constant increase in the growth of the cloud market creates new challenges for cloud service providers. One such challenge is the need to avoid possible service level agreement (SLA) violations and their consequences through good SLA management. Researchers have proposed various frameworks and have made significant advances in managing SLAs from the perspective of both cloud users and providers. However, none of these approaches guides the service provider on the necessary steps to take for SLA violation abatement; that is, the prediction of possible SLA violations, the process to follow when the system identifies the threat of SLA violation, and the recommended action to take to avoid SLA violation. In this paper, we approach this process of SLA violation detection and abatement from a risk management perspective. We propose a Risk Management-based Framework for SLA violation abatement (RMF-SLA) following the formation of an SLA which comprises SLA monitoring, violation prediction and decision recommendation. Through experiments, we validate and demonstrate the suitability of the proposed framework for assisting cloud providers to minimize possible service violations and penalties

    Action antibactĂ©rienne de l’extrait Ă©thanolique 70% de Clerodendrum splendens (G. Don) (Verbenacae) sur des souches bactĂ©riennes isolĂ©es de selles chez des enfants diarrhĂ©iques

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    L’apparition des bactĂ©ries rĂ©sistantes aux antibiotiques et leur diffusion dans la population humaine constituent un rĂ©el problĂšme de santĂ© publique. C’est ainsi que le monde scientifique a dĂ©couvert de nombreux traitements qui ont permis de rĂ©duire l’indice des maladies causĂ©es par ces germes. MalgrĂ© ce succĂšs, on ne cesse d’enregistrer la rĂ©sistance des bactĂ©ries aux antibactĂ©riens. Ainsi, le dĂ©veloppement de nouveaux agents antibactĂ©riens s’avĂšre indispensable pour lutter contre ces flĂ©aux. C’est dans ce but que notre objectif vise Ă  tester l’extrait Ă©thanolique 70% de Clerodendrum splendens (G.don) sur quelques entĂ©robactĂ©ries isolĂ©es de selles chez des enfants diarrhĂ©iques. La mĂ©thode de dilution en milieu liquide gĂ©losĂ© Muller-HintonÂź utilisant diffĂ©rentes concentrations d’extrait a permis d’évaluer l’activitĂ© antibactĂ©rienne de l’extrait. Les rĂ©sultats obtenus montrent que toutes les souches bactĂ©riennes sont sensibles Ă  l’extrait Ă©thanolique 70%. Cet extrait est bactĂ©ricide sur Proteus mirabilis et bactĂ©riostatique sur Escherichia coli, Salmonella typhi et Shigella sp.Mots clĂ©s: Extrait Ă©thanolique 70%, Clerodendrum splendens, EntĂ©robactĂ©ries, DiarrhĂ©e, BactĂ©riostatique, BactĂ©ricide

    Attitude towards psychiatric treatment and referral pattern in the University of Maiduguri Teaching Hospital- A preliminary report

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    Objective: There is a paucity of literature on consultation-liaison psychiatry, in northern Nigeria. This study aimed to determine both the pattern of psychiatric referrals, and the attitudes of doctors toward the treatment of mental disorders in a teaching hospital, in northeast Nigeria. Method: In this cross-sectional survey, we used a modified version of the self-rated Kumar 12-item questionnaire and a basic socio-demographic questionnaire to assess a non-random convenient sample of 100 postgraduate resident doctors (with a response rate of 70%) from the University of Maiduguri Teaching Hospital (UMTH). We subjected the dataobtained to descriptive statistical analysis, using EPI info (2003), to report averages. Results: A relatively low percentage (57.1%) of doctors acknowledged treating patients with mental disorders in their practice, with a higher proportion acknowledging referral (75%). Nearly one in five (17.6%) of the respondents were unaware that patients with functional illness could have psychological disorders. We found more awareness for psychotherapy (44.1%) than other non-pharmacological treatment interventions, while10.3% were ignorant of non-pharmacological forms of treatment for psychological problems. Conclusion: Although this is a preliminary report, the research reported here demonstrated that doctors in the teaching hospital concerned recognized the need for psychiatric consultation and referral. It is difficult to draw further conclusions because of the limitations of this study.Keywords: Consultation; Liaison; Psychiatry; northern Nigeri

    Improved timed-mating, non-invasive method using fewer unproven female rats with pregnancy validation via early body mass increases

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    For studies requiring accurate conception-timing, reliable, efficient methods of detecting oestrus reduce time and costs, whilst improving welfare. Standard methods use vaginal cytology to stage cycle, and breeders are paired–up using approximately five proven females with proven males to achieve at least one conception on a specific day. We describe an alternative, fast, consistent, non-invasive method of timed-mating using detection of lordosis behaviour in Wistar and Lister-Hooded rats that used unproven females with high success rates. Rats under reverse-lighting had body masses recorded pre-mating, day (d) 3-4, d8, d10 and d18 of pregnancy. Using only the presence of the oestrus dance to time-mate females for 24-hrs, 89% Wistar and 88% Lister-Hooded rats successfully conceived. We did not observe behavioural oestrus in Sprague-Dawleys without males present. Significant body mass increases following mating distinguished pregnant from non-pregnant rats, as early as d4 of pregnancy (10% ± 1.0 increase cf 3% ± 1.2). The pattern of increases throughout gestation was similar for all pregnant rats until late pregnancy, when there were smaller increases for primi- and multiparous rats (32% ± 2.5; 25% ± 2.4), whereas nulliparous rats had highest gains (38% ± 1.5). This method demonstrated a distinct refinement of the previous timed-mating common practice used, as disturbance of females was minimised. Only the number required of nulli-, primi- or multiparous rats were mated, and body mass increases validated pregnancy status. This new breeding-management method is now established practice for two strains of rat and resulted in a reduction in animal use

    Random UV-C mutagenesis of Scheffersomyces (formerly Pichia) stipitis NRRL Y-7124 to improve anaerobic growth on lignocellulosic sugars

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    Scheffersomyces (formerly Pichia) stipitis NRRL Y-7124 was mutagenized using UV-C irradiation to produce yeast strains for anaerobic conversion of lignocellulosic sugars to ethanol. UV-C irradiation potentially produces large numbers of random mutations broadly and uniformly over the whole genome to generate unique strains. Wild-type cultures of S. stipitis NRRL Y-7124 were subjected to UV-C (234 nm) irradiation targeted at approximately 40% cell survival. When surviving cells were selected in sufficient numbers via automated plating strategies and cultured anaerobically on xylose medium for 5 months at 28°C, five novel mutagenized S. stipitis strains were obtained. Variable number tandem repeat analysis revealed that mutations had occurred in the genome, which may have produced genes that allowed the anaerobic utilization of xylose. The mutagenized strains were capable of growing anaerobically on xylose/glucose substrate with higher ethanol production during 250- to 500-h growth than a Saccharomyces cerevisiae yeast strain that is the standard for industrial fuel ethanol production. The S. stipitis strains resulting from this intense multigene mutagenesis strategy have potential application in industrial fuel ethanol production from lignocellulosic hydrolysates

    Thermoelectric spin voltage in graphene

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    In recent years, new spin-dependent thermal effects have been discovered in ferromagnets, stimulating a growing interest in spin caloritronics, a field that exploits the interaction between spin and heat currents. Amongst the most intriguing phenomena is the spin Seebeck effect, in which a thermal gradient gives rise to spin currents that are detected through the inverse spin Hall effect. Non-magnetic materials such as graphene are also relevant for spin caloritronics, thanks to efficient spin transport, energy-dependent carrier mobility and unique density of states. Here, we propose and demonstrate that a carrier thermal gradient in a graphene lateral spin valve can lead to a large increase of the spin voltage near to the graphene charge neutrality point. Such an increase results from a thermoelectric spin voltage, which is analogous to the voltage in a thermocouple and that can be enhanced by the presence of hot carriers generated by an applied current. These results could prove crucial to drive graphene spintronic devices and, in particular, to sustain pure spin signals with thermal gradients and to tune the remote spin accumulation by varying the spin-injection bias

    Global burden of human brucellosis : a systematic review of disease frequency

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    BACKGROUND: This report presents a systematic review of scientific literature published between 1990-2010 relating to the frequency of human brucellosis, commissioned by WHO. The objectives were to identify high quality disease incidence data to complement existing knowledge of the global disease burden and, ultimately, to contribute towards the calculation of a Disability-Adjusted Life Years (DALY) estimate for brucellosis.METHODS/PRINCIPAL FINDINGS: Thirty three databases were searched, identifying 2,385 articles relating to human brucellosis. Based on strict screening criteria, 60 studies were selected for quality assessment, of which only 29 were of sufficient quality for data analysis. Data were only available from 15 countries in the regions of Northern Africa and Middle East, Western Europe, Central and South America, Sub-Saharan Africa, and Central Asia. Half of the studies presented incidence data, six of which were longitudinal prospective studies, and half presented seroprevalence data which were converted to incidence rates. Brucellosis incidence varied widely between, and within, countries. Although study biases cannot be ruled out, demographic, occupational, and socioeconomic factors likely play a role. Aggregated data at national or regional levels do not capture these complexities of disease dynamics and, consequently, at-risk populations or areas may be overlooked. In many brucellosis-endemic countries, health systems are weak and passively-acquired official data underestimate the true disease burden.CONCLUSIONS: High quality research is essential for an accurate assessment of disease burden, particularly in Eastern Europe, the Asia-Pacific, Central and South America and Africa where data are lacking. Providing formal epidemiological and statistical training to researchers is essential for improving study quality. An integrated approach to disease surveillance involving both human health and veterinary services would allow a better understand of disease dynamics at the animal-human interface, as well as a more cost-effective utilisation of resources

    From Nonspecific DNA–Protein Encounter Complexes to the Prediction of DNA–Protein Interactions

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    ©2009 Gao, Skolnick. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.doi:10.1371/journal.pcbi.1000341DNA–protein interactions are involved in many essential biological activities. Because there is no simple mapping code between DNA base pairs and protein amino acids, the prediction of DNA–protein interactions is a challenging problem. Here, we present a novel computational approach for predicting DNA-binding protein residues and DNA–protein interaction modes without knowing its specific DNA target sequence. Given the structure of a DNA-binding protein, the method first generates an ensemble of complex structures obtained by rigid-body docking with a nonspecific canonical B-DNA. Representative models are subsequently selected through clustering and ranking by their DNA–protein interfacial energy. Analysis of these encounter complex models suggests that the recognition sites for specific DNA binding are usually favorable interaction sites for the nonspecific DNA probe and that nonspecific DNA–protein interaction modes exhibit some similarity to specific DNA–protein binding modes. Although the method requires as input the knowledge that the protein binds DNA, in benchmark tests, it achieves better performance in identifying DNA-binding sites than three previously established methods, which are based on sophisticated machine-learning techniques. We further apply our method to protein structures predicted through modeling and demonstrate that our method performs satisfactorily on protein models whose root-mean-square Ca deviation from native is up to 5 Å from their native structures. This study provides valuable structural insights into how a specific DNA-binding protein interacts with a nonspecific DNA sequence. The similarity between the specific DNA–protein interaction mode and nonspecific interaction modes may reflect an important sampling step in search of its specific DNA targets by a DNA-binding protein
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