Efficient calculation of formation energies of kink-pairs in BCC crystals

En materiales con estructura cristalina BCC el movimiento de dislocaciones de tipo tornillo a baja temperatura está asociado con la formación y el crecimiento de escalones en la línea de la dislocación. Para entender la movilidad de dislocaciones de tipo tornillo en estos materiales es muy importante la correcta predicción de las energías de nucleación de estos escalones. El cálculo a nivel atomístico de la mecánica de dislocaciones constituye un problema complicado desde el punto de vista tanto numérico como computacional. Este trabajo se centra en el cálculo de las energías de formación de distintas configuraciones de escalones dobles en cristales BCC y en ausencia de cargas exteriores. En nuestro modelo, basado en la teoría discreta de dislocaciones desarrollada por Ariza y Ortiz, la energía almacenada se calcula de forma eficiente mediante un algoritmo de programación basado en NVIDIA Compute Unified Device Architecture (CUDA). Los resultados obtenidos presentan un buen acuerdo con los calculados utilizando primeros principios y potenciales atomísticos, y los correspondientes a la teoría elástica de dislocaciones.Motion of screw dislocations in BCC materials at low temperature is believed to be related to the formation of mobile kinks on the dislocation line. Therefore, the accurate prediction of kink nucleation energies is required to fully describe mobility of screw dislocations in these materials. Studies of fundamental dislocation processes at atomic length scale are numerically and computationally intensive problems. This work studies the calculation of zero-stress formation energies of kink-pair configurations for BCC crystals. Our model for stored energy associated to a dislocation line configuration is based on the theory of discrete dislocations of Ariza and Ortiz. Its value is computed efficiently using an algorithm developed on the NVIDIA Compute Unified Device Architecture (CUDA). Results confirm those obtained using atomistic potentials and first principles calculations, and those based on the continuum theory of dislocations.Peer Reviewe

Adoption of Business Model Canvas in Exploring Digital Business Transformation

Digital Business Transformation (DBT) values and contributions are still unrecognized by many organizations. Managers face problems in initiating their digital transformation due to the challenges and complexities in the realization of these processes. Business Model Canvas (BMC) – known as a semantically enriched tool for business model analysis and design – is a rather novel approach proposed to solve this problem. It is used to highlight organizations’ capabilities and verify the role of IT systems in organizations. Further empirical investigations are required to identify BMCs role in DBT and specify the main changes caused by IT systems. For this purpose, a case study of “The Faculty of Scientific Research at Zarqa University” is used to demonstrate how BMC can be utilized as a part of the DBT process, where a new internal IT system for Scientific Research is introduced, and BMC is implemented through. The Scientific Research Information System (SRIS) has been used to manage the research in the faculty. The BMC design was implemented pre and post-using the SRIS. A proposed model was derived based on the difference between both implementations. A quantitative approach using an online questionnaire was accomplished to evaluate this model and measure its new elements post using SRIS. The research results show that Key Activities, Key Resources, Value Propositions, Customer Relationships, and Channels are the main zones related to DBT. In addition, the changes in the elements of Key Resources are the essential motive and the cornerstone of DBT

Impact of the ash deposits from coal combustion on thermal conditions of the furnace pipes

One of the problems of thermal power plants is the contamination of heating surfaces that arises during the boiler unit operation while combusting the solid fuel. The main part of the energy is consumed by pipes forming the furnace. Non-combustible mineral part of the fuel in the form of the ash and slag accumulates on the heating surfaces and thereby prevents heating of the working liquid. Therefore, boiler requires higher fuel consumption to maintain the operating conditions. Violation of the thermal conditions of heating surfaces in consequence of contamination causes the negative effects on metal pipes right up to failure. This problem is urgent due to the fact that information about the process of slagging and its effect on the thermal conditions of the heating surface operation enables the possibility to minimize the negative consequences. This possibility is achieved by adjusting the thermal conditions of the combustion process in the furnace with the periodic cleaning of the heating surfaces

Clinicopathological evaluation of intranasal, subcutaneous and intramuscular routes of vaccination against intratracheal challenge of Peste des petits ruminants virus in goats

An experiment was conducted to compare the efficacy of intranasal vaccination against caprine Peste des petits ruminant lineage 1 variant virus infection with intramuscular and subcutaneous vaccinations. Twenty four goats were divided into four equal groups. Group 1 was vaccinated intranasally, group 2 was vaccinated subcutaneously, and group 3 intramuscularly, while group 4 was the unvaccinated control. In each group, the vaccinations were carried out once. All goats were challenged intratracheally with PPR virus at a concentration of 106.5 TCID50 two weeks after vaccination and were euthanised 21 days after the challenge. The clinical, lung consolidation, gross and histopathological scores were employed using standard techniques. All data were analysed statistically using the paired t-test and one-way analysis of variance (ANOVA). Group 3 had the highest clinical score following the challenge of vaccinated group while deaths were observed only in group 4. Three goats in group 2 and 3 had pneumonic lung lesions, compared with none in group 1 and all the goats in group 4. The lung lesions in group 4 were significantly (P 0.05) while group 1 had no consolidation. This study showed that PPR vaccination using subcutaneous, intramuscular and intranasal routes were protective but that of intranasal was found to be easy to apply hence it could be used for the prevention of the disease in small ruminants

The effect of heat stress on the oxidative status of red hybrid tilapia (Oreochromis sp.) infected with Streptococcus Agalactiae

A commercial red hybrid tilapia was experimented with S. agalactiae infection under influences of heat stress which indicated by plasma malondialdehyde (MDA) and erythrocyte superoxide dismutase (SOD) as biomarkers of stress. To achieve these objectives, 110 red hybrid tilapia in good health were divided into five groups of 22 fish each. Group A was challenged with 2.3 109 CFU of S. agalactiae and exposed to heat stress at 33 ± 0.5C on day 1. Group B was challenged on day 1 as in Group A but heat stress was introduced on day 7 post challenge (pc). Group C was exposed to heat stress on day 1 and challenged on day 7 pc while groups D and E served as a positive and negative controls respectively. Blood samples were collected at days 0, 3, 7, 10 and 14 for MDA and SOD analysis. Groups A and B recorded high mortality following exposure to heat stress and bacteria inoculation, with group A reaching 100% mortality at day 7 post inoculation. Overall, Groups A, B, C and Group D showed pattern of increase in MDA level as early as day 3 and decrease pattern for SOD activity. Group E did not show any significant difference in MDA level throughout the study period. Clinical signs such as erratic swimming, exopthalmia, skin haemorrhage and cloudy eye were predominantly observed in group A 24 h post inoculation. Based on the findings of this study, it was concluded that heat stress plays crucial role in the pathogenesis of S. agalactiae, via alteration of the oxidant defence system

Ground-truth prediction to accelerate soft-error impact analysis for iterative methods

Understanding the impact of soft errors on applications can be expensive. Often, it requires an extensive error injection campaign involving numerous runs of the full application in the presence of errors. In this paper, we present a novel approach to arriving at the ground truth-the true impact of an error on the final output-for iterative methods by observing a small number of iterations to learn deviations between normal and error-impacted execution. We develop a machine learning based predictor for three iterative methods to generate ground-truth results without running them to completion for every error injected. We demonstrate that this approach achieves greater accuracy than alternative prediction strategies, including three existing soft error detection strategies. We demonstrate the effectiveness of the ground truth prediction model in evaluating vulnerability and the effectiveness of soft error detection strategies in the context of iterative methods.This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research under Award Number 66905, program manager Lucy Nowell. Pacific Northwest National Laboratory is operated by Battelle for DOE under Contract DE-AC05-76RL01830.Peer ReviewedPostprint (author's final draft

Neural correlates of the DemTect in Alzheimer's disease and frontotemporal lobar degeneration ? A combined MRI & FDG-PET study ?

Valid screening devices are critical for an early diagnosis of dementia. The DemTect is such an internationally accepted tool. We aimed to characterize the neural networks associated with performance on the DemTect's subtests in two frequent dementia syndromes: early Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD). Voxel-based group comparisons of cerebral glucose utilization (as measured by F-18-fluorodeoxyglucose positron emission tomography) and gray matter atrophy (as measured by structural magnetic resonance imaging) were performed on data from 48 subjects with AD (n = 21), FTLD (n = 14) or subjective cognitive impairment (n = 13) as a control group. We performed group comparisons and correlation analyses between multimodal imaging data and performance on the DemTect's subtests. Group comparisons showed regional patterns consistent with previous findings for AD and FTLD. Interestingly, atrophy dominated in FTLD, whereas hypometabolism in AD. Across diagnostic groups performance on the "wordlist" subtest was positively correlated with glucose metabolism in the left temporal lobe. The "number transcoding" subtest was significantly associated with glucose metabolism in both a predominantly left lateralized frontotemporal network and a parietooccipital network including parts of the basal ganglia. Moreover, this subtest was associated with gray matter density in an extensive network including frontal, temporal, parietal and occipital areas. No significant correlates were observed for the "supermarket task" subtest. Scores on the "digit span reverse" subtest correlated with glucose metabolism in the left frontal cortex, the bilateral putamen, the head of caudate nucleus and the anterior insula. Disease-specific correlation analyses could partly verify or extend the correlates shown in the analyses across diagnostic groups. Correlates of gray matter density were found in FTLD for the "number transcoding" subtest and the "digit span reverse" subtest. Correlates of glucose metabolism were found in AD for the "wordlist" subtest and in FTLD for the "digit span reverse" subtest. Our study contributes to the understanding of the neural correlates of cognitive deficits in AD and FTLD and supports an external validation of the DemTect providing preliminary conclusions about disease-specific correlates

Impact of Beta-Amyloid-Specific Florbetaben PET Imaging on Confidence in Early Diagnosis of Alzheimer’s Disease

BACKGROUND: Early diagnosis of Alzheimer's disease (AD) may be corroborated by imaging of beta-amyloid plaques using positron emission tomography (PET). Here, we performed an add-on questionnaire study to evaluate the relevance of florbetaben imaging (BAY 949172) in diagnosis and consecutive management of probable AD patients. METHODS: AD patients with a clinical diagnosis in accordance with the NINCDS-ADRDA criteria or controls were imaged using florbetaben. Referring physicians were asked on a voluntary basis about their confidence in initial diagnosis, significance of PET imaging results, and their anticipated consequences for future patient care. RESULTS: 121 questionnaires for probable AD patients and 80 questionnaires for controls were evaluated. In 18% of patients who had initially received the diagnosis of probable AD, PET scans were rated negative, whereas in controls 18% of scans were positive. An increase in confidence in the initial diagnosis was frequently reported (80%). Imaging results had a significant impact on the intended patient care, as judged by the referring physicians; this was most prominent in those patients with a contradicting scan and/or a low confidence in the initial diagnosis. CONCLUSION: Florbetaben amyloid imaging increases the overall confidence in diagnosis of AD and may frequently influence clinical decisions and patient management