The bipolaron model in transport properties of YBa2Cu3Oy superconductor prepared by adding Pr2Co7 magnetic nanoparticles

Samples with the addition of ferromagnetic nanoparticles of Pr2Co7 on YBa2Cu3Oy (YBCO) polycrystalline superconductor were prepared by the standard solid state reaction method. The analysis of x-ray diffraction patterns by Rietveld refinement indicates orthorhombique to tetragonal phase transformation and oxygen rate reduction from x=0.3% of Pr2Co7 content. Resistivity at room temperature increases as Pr2Co7 content increases. The normal state resistivity versus temperature was analyzed properly by the bipolaron model. It suggested the increase of mobile charge localization with Pr2Co7 content.Keywords: Pr2Co7 ferromagnetic nanoparticles, high temperature superconductor, bipolaron model, localization of mobile charg

Effect of annealing treatments on normal state resistivity of YBa2(Cu1-xTix)3Oy superconductor in bipolaron model

Samples of YBa2(Cu1-xTix)3Oy superconductor with x=0.00 , 0.01, 0.03 have been prepared by solide state reaction method. The effect of annealing treatments on normal electrical resistivity has been done using the bipolaron model. The results of this study show the increase of localized charge when the dopant content increases and the reduction of this localization with annealing treatment.Keywords: YBa2(Cu1-xTix)3Oy superconductor, normal state, bipolaro

Conception et réalisation des capteurs hybrides photovoltaïque-thermiques sous vide ou avec lame d’air confinée

Cette étude fait l’analyse des performances thermiques et électriques de deux types de capteurs solaires hybrides photovoltaïque-thermiques à air intégrables en toitures des bâtiments. Pour ces capteurs hybrides, les cellules PV sont isolées soit avec une lame d’air confinée ou soit avec un gap vide. La modélisation des transferts de chaleur dans les systèmes est effectuée en 2D et en régime transitoire, suivant l’approche nodale. Le code numérique développé a été validé et a permis d’analyser les comportements thermiques ainsi que les efficacités thermique et électrique des capteurs. L’optimisation des paramètres fonctionnels est ensuite effectuée et présentée.Mots-clés: énergie solaire, cellules photovoltaïques, capteurs solaires hybrides (PV/T), transferts thermiques. Conception and realization of hybrid photovoltaic thermal collectors with empty gap or with enclosed air cavityThe present work reports thermal and electrical efficiencies for two solar hybrid photovoltaic-thermal air collectors integrated into the roof of the buildings. In these hybrid collectors, the PV cells are insulated with the enclosed air film or with the empty gap cavity. The unsteady and two-dimensional heat transfer equations are proposed and these equations are discretized using nodal method. The numerical model developed is validated. Then thermal and electrical efficiencies are analyzed for the collectors. The optimization of the characteristics parameters is studied in detail.Keywords: solar energy, photovoltaic cells, hybrid solar collector, heat transfer, nodal method

A qualitative exploration of the experiences of veterans who are serving sentences in custody

The focus on veterans in research is not a novel topic; however, the majority of studies are related to trauma, employment, mental health, suicide, and substance misuse. The Criminal Justice System involvement with veterans is a topic that has yet to be examined to a great extent. This study, conducted with adult male prisoners, elicited information from six veterans regarding their experiences of being in the armed forces, leaving the armed forces and becoming involved in the Criminal Justice System. Responses were evaluated using Interpretative Phenomenological Analysis (IPA) and three main themes were identified: “you’re baptised into the army”, ‘them and us,’ and ‘operational mind set’; each of which comprised a number of superordinate themes. The research highlights that, although it is important to acknowledge the heterogenic nature of this group, it is equally important to note that much of their thinking and behaviour may be similar to those that have not had these experiences. As such, there is a need to reduce the notion that they are separate and different to other prisoners, requiring different treatment. The study highlights that many of the Offending Behaviour Programmes and interventions already available to prisoners would be appropriate for this group. The current research supports the merit in creating a service in prisons that will allow for ex-servicemen to meet together and access the support that is available to them. The implications of the research are discussed further

Association of Genetic Variants With Primary Open-Angle Glaucoma Among Individuals With African Ancestry.

Importance:Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders. Objectives:To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma. Design, Settings, and Participants:A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma. Exposures:Genetic variants associated with primary open-angle glaucoma. Main Outcomes and Measures:Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data. Results:A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-β A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry. Conclusions and Relevance:In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies

Unravelling the spirits’ message: a study of help-seeking steps and explanatory models among patients suffering from spirit possession in Uganda

As in many cultures, also in Uganda spirit possession is a common idiom of distress associated with traumatic experiences. In the DSM-IV and -5, possession trance disorders can be classified as dissociative disorders. Dissociation in Western countries is associated with complicated, time-consuming and costly therapies. Patients with spirit possession in SW Uganda, however, often report partial or full recovery after treatment by traditional healers. The aim of this study is to explore how the development of symptoms concomitant help-seeking steps, and explanatory models (EM) eventually contributed to healing of patients with spirit possession in SW Uganda. Illness narratives of 119 patients with spirit possession referred by traditional healers were analysed using a mixed-method approach. Treatments of two-thirds of the patients were unsuccessful when first seeking help in the medical sector. Their initially physical symptoms subsequently developed into dissociative possession symptoms. After an average of two help-seeking steps, patients reached a healing place where 99% of them found satisfactory EM and effective healing. During healing sessions, possessing agents were summoned to identify themselves and underlying problems were addressed. Often-mentioned explanations were the following: neglect of rituals and of responsibilities towards relatives and inheritance, the call to become a healer, witchcraft, grief, and land conflicts. The results demonstrate that traditional healing processes of spirit possession can play a role in restoring connections with the supra-, inter-, intra-, and extra-human worlds. It does not always seem necessary to address individual traumatic experiences per se, which is in line with other research in this field. The study leads to additional perspectives on treatment of trauma-related dissociation in Western countries and on developing effective mental health services in low -and middle-income countries

Obtention du PVK dopé par les hallogènes

(Journal de la Recherche Scientifique de l'Université de Lomé: 2001 5(1): 145-150

Infrared spectroscopy of the different types of second order structural phase transitions in molecular crystals

No Abstract.Global Journal of Pure and Applied Sciences Vol. 13 (1) 2007: pp. 119-12