199 research outputs found

    Atmospheric conditions of extreme precipitation events in western Turkey for the period 2006–2015

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    This paper investigates the precipitation types and background physical mechanisms of extreme precipitation events (EPEs) over western Turkey during the period 2006–2015. The EPEs are described as the precipitation values above the 90th percentile obtained from the hourly precipitation dataset, which has high spatial resolution. Precipitation types associated with EPEs are identified by using radar outputs and the Lamb weather type (LWT) approach. It is found that EPEs occurred more frequently in the Marmara and Aegean regions during autumn and winter months. In Marmara, mainly 21&thinsp;%, 17&thinsp;%, and 15&thinsp;% of total autumn EPEs show convective, cyclonic, and sea-effect precipitation characteristics, respectively. While convective EPEs are seen more commonly in the southern portions, cyclonic and sea-effect-originated EPEs mainly affect the southwest and northeastern parts of Marmara. Among these three precipitation types, convective mechanisms generally produce more intense daily precipitation (66.1&thinsp;mm on average) in the Marmara Region under the proper synoptic conditions (high-pressure center over the Balkan Peninsula and low-pressure center over the eastern Mediterranean). Based on the hourly observations, convective types of extreme precipitation (EP) show two peak values during afternoon and evening times of the day and are linked to diurnal heating. In terms of the Aegean Region, cyclone-originated EP, which includes 65&thinsp;% of the total winter EPEs, is more common in the whole territory and reaches its peak value during the early hours of the day.</p

    Dumlupınar Üniversitesi Öğrencilerinin İnternet Kullanım Ve Doyum Motivasyonlarının Bazı Parametreler Bakımından İncelenmesi,

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    İletişim teknolojilerindeki hızlı gelişmeler sonucunda internetin toplumsal yaşamımızdaki önemi hızla artmıştır. İnternet birçok alanda kullanıcısına fayda sağlamaktadır. Bunlar; bilgi edinme, eğlence, sohbet, alışveriş, iletişim gibi farkörler bunların başında gelmektedir. Bu araştirmada, katılımcıların bazı parametrelerinin internet kullanımında etkili olan 6 faktör üzerindeki etkilerinin incelenmesi amaçlanmıştır. Araştırma Kütahya Dumlupınar Üniversitesi “Beden Eğitimi Spor Yüksek Okulu, Mühendislik Fakültesi, İİBF, Eğitim Fakültesi, Fen edebiyat Fakültesinde” okuyan basit tesadüfî örneklem yoluyla seçilen 691 öğrenci üzerinde uygulamalı olarak gerçekleştirilmiştir. Araştırmaya 309 Bayan ve 382 erkek katılım sağlamıştır. Katılımcılara spor aktiviteleri, günlük hayatları, internet kullanım farklıklılıkları, süreleri gibi bazı sorular yöneltilmiştir. Ayrıca katılımcıların demografik özellikleride belirlenmiştir. Ailelerinin ekonomik, eğitim ve yaşadıkları bölgeler hakkında da bilgi toplanmıştır. Elde edilen bu bilgilerle uygulamaya gidilmiştir. Uygulamada SPSS istatistik 15 programı kullanılarak analiz gerçekleştirilmiştir. Analizde farklı teknikler ve yöntemler kullanılmıştır. Uygulama ve analizden elde edilen veriler çalışmanın tartışma ve sonuç kısmında açıklanmıştır. Çalışma sonunda, internet kullanımının motivasyon ve doyum düzeyi üzerinde etkili olduğu sonucuna ulaşılmıştır

    Assignment Of Opsonic Values To Pneumococcal Reference Serum 007SP For Use In Opsonophagocytic Assays For 13 Serotypes

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    Opsonophagocytic assays (OPAs) are routinely used for assessing the immunogenicity of pneumococcal vaccines, with OPA data often utilized for licensure of new vaccine formulations. However, no reference serum for pneumococcal OPAs is available, making evaluation of data among different laboratories difficult. This international collaboration was initiated to: 1) assign consensus opsonic indexes (OIs) to Pneumococcal Reference Serum Lot 007sp ("007sp") and a panel of calibration sera; and 2) determine if normalization with 007sp decreases the OPA variability among laboratories.To meet these goals, six participating laboratories tested a panel of sera in five runs for 13 serotypes. For each serum, consensus OIs were obtained using a mixed effects ANOVA model. For the calibration sera, normalized consensus values were also determined based on 007sp.For each serotype, the overall reduction in inter-laboratory variability was calculated by comparing the coefficients of variation of the unadjusted and the normalized values. Normalization of the results substantially reduced the inter-laboratory variability, ranging from a 15% reduction in variability for serotype 9V to 64% for serotype 7F. Normalization also increased the proportion of data within 2-fold of the consensus value from approximately 70% (average of all serotypes) to >90%.Based on the data obtained in this study, Pneumococcal Reference Standard Lot 007sp will likely be a useful reagent for normalizing pneumococcal OPA results from different laboratories. The data also support the use of the 16 FDA OPA calibration sera as part of the initial evaluation of new assays or periodic assessment of established assays

    Increasing student engagement through virtual interactions: how?

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    Our ongoing research is focusing on identifying and taxonomising the elements and the factors that affect learner engagement with virtual worlds when hybrid virtual learning models are used. Our main hypothesis links learner engagement with interactions, both in the virtual world and in the physical classroom. In order to examine this subject, there is an elaboration on and consideration of aspects such as the learners’ prior experiences in the use of virtual worlds, their preconceptions about using them as a learning tool and the impact that the instructional designers’ choices have on enhancing the opportunities for interactions. In this paper, we examine the impact that the orientation process has on university students who study computer science and have almost no experience in the use of virtual worlds. Our findings suggest that the orientation process contributed positively to students’ smooth induction and that resulted in having meaningful and engaging interactions. Furthermore, students’ simultaneous coexistence in both environments eliminated the drawbacks of each educational approach and broadened the network of interactions

    Epigenetic Silencing of Host Cell Defense Genes Enhances Intracellular Survival of the Rickettsial Pathogen Anaplasma phagocytophilum

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    Intracellular bacteria have evolved mechanisms that promote survival within hostile host environments, often resulting in functional dysregulation and disease. Using the Anaplasma phagocytophilum–infected granulocyte model, we establish a link between host chromatin modifications, defense gene transcription and intracellular bacterial infection. Infection of THP-1 cells with A. phagocytophilum led to silencing of host defense gene expression. Histone deacetylase 1 (HDAC1) expression, activity and binding to the defense gene promoters significantly increased during infection, which resulted in decreased histone H3 acetylation in infected cells. HDAC1 overexpression enhanced infection, whereas pharmacologic and siRNA HDAC1 inhibition significantly decreased bacterial load. HDAC2 does not seem to be involved, since HDAC2 silencing by siRNA had no effect on A. phagocytophilum intracellular propagation. These data indicate that HDAC up-regulation and epigenetic silencing of host cell defense genes is required for A. phagocytophilum infection. Bacterial epigenetic regulation of host cell gene transcription could be a general mechanism that enhances intracellular pathogen survival while altering cell function and promoting disease

    Cyclical and Patch-Like GDNF Distribution along the Basal Surface of Sertoli Cells in Mouse and Hamster Testes

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    BACKGROUND AND AIMS: In mammalian spermatogenesis, glial cell line-derived neurotrophic factor (GDNF) is one of the major Sertoli cell-derived factors which regulates the maintenance of undifferentiated spermatogonia including spermatogonial stem cells (SSCs) through GDNF family receptor α1 (GFRα1). It remains unclear as to when, where and how GDNF molecules are produced and exposed to the GFRα1-positive spermatogonia in vivo. METHODOLOGY AND PRINCIPAL FINDINGS: Here we show the cyclical and patch-like distribution of immunoreactive GDNF-positive signals and their close co-localization with a subpopulation of GFRα1-positive spermatogonia along the basal surface of Sertoli cells in mice and hamsters. Anti-GDNF section immunostaining revealed that GDNF-positive signals are mainly cytoplasmic and observed specifically in the Sertoli cells in a species-specific as well as a seminiferous cycle- and spermatogenic activity-dependent manner. In contrast to the ubiquitous GDNF signals in mouse testes, high levels of its signals were cyclically observed in hamster testes prior to spermiation. Whole-mount anti-GDNF staining of the seminiferous tubules successfully visualized the cyclical and patch-like extracellular distribution of GDNF-positive granular deposits along the basal surface of Sertoli cells in both species. Double-staining of GDNF and GFRα1 demonstrated the close co-localization of GDNF deposits and a subpopulation of GFRα1-positive spermatogonia. In both species, GFRα1-positive cells showed a slender bipolar shape as well as a tendency for increased cell numbers in the GDNF-enriched area, as compared with those in the GDNF-low/negative area of the seminiferous tubules. CONCLUSION/SIGNIFICANCE: Our data provide direct evidence of regionally defined patch-like GDNF-positive signal site in which GFRα1-positive spermatogonia possibly interact with GDNF in the basal compartment of the seminiferous tubules
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