489 research outputs found
Multidetector computed tomography findings of an asymptomatic levoatrial cardinal vein with an interatrial course
A 57-year-old female patient with a family history of coronary artery diseaseadmitted to our hospital for the coronary check-up. A coronary angiographywas performed with ECG-gated 128 slice dual source computed tomography.Multidetector computed tomography (MDCT) showed, in addition to the normalcoronary arteries, a persistent levoatrial cardinal vein (LCV) draining into vena cavasuperior. ECG-gated cardiac MDCT is a useful tool showing the origin, course, anddrainage site of LCV
A Chemoattractant Role for NT-3 in Proprioceptive Axon Guidance
Neurotrophin-3 (NT-3) is required for proprioceptive neuron survival. Deletion of the proapoptotic gene Bax in NT-3 knockout mice rescues these neurons and allows for examination of their axon growth in the absence of NT-3 signaling. TrkC-positive peripheral and central axons from dorsal root ganglia follow proper trajectories and arrive in close proximity to their targets but fail to innervate them. Peripherally, muscle spindles are absent and TrkC-positive axons do not enter their target muscles. Centrally, proprioceptive axons branch in ectopic regions of the spinal cord, even crossing the midline. In vitro assays reveal chemoattractant effects of NT-3 on dorsal root ganglion axons. Our results show that survival factor NT-3 acts as a short-distance axon guidance molecule for muscle sensory afferents as they approach their proper targets
Which shape representation is the best for real-time hand interface system?
Hand is a very convenient interface for immersive human-computer interaction. Users can give commands to a computer by hand signs (hand postures, hand shapes) or hand movements (hand gestures). Such a hand interface system can be realized by using cameras as input devices, and software for analyzing the images. In this hand interface system, commands are recognized by analyzing the hand shapes and its trajectories in the images. Therefore, success of the recognition of hand shape is vital and depends on the discriminative power of the hand shape representation. There are many shape representation techniques in the literature. However, none of them are working properly for all shapes. While a representation leads to a good result for a set of shapes, it may fail in another one. Therefore, our aim is to find the most appropriate shape representation technique for hand shapes to be used in hand interfaces. Our candidate representations are Fourier Descriptors, Hu Moment Invariant, Shape Descriptors and Orientation Histogram. Based on widely-used hand shapes for an interface, we compared the representations in terms of their discriminative power and speed. © 2009 Springer-Verlag
Laser powder bed fusion of NdFeB and influence of powder bed heating on density and magnetic properties
Laser powder bed fusion (L-PBF) is an additive manufacturing technique that provides an opportunity to create complex NdFeB magnets, potentially enhancing their performance. L-PBF possesses its own processing challenges, such as porosity/cracks and thermal stresses due to rapid cooling. This study focused on optimizing the parameters and the use of elevated temperature (300–550 °C) powder bed heating to reduce defect generation. This paper includes a detailed process parameter investigation, which revealed samples with a maximum energy product, (BH)max, of 81 kJ/m3 (remanence, Br 0.72 T; coercivity, Hci 891 kA/m) without post/pretreatment, which are the highest (BH)max and Br for L-PBF-processed NdFeB commercial powder. It was observed that all the high-magnetism samples possessed high density, but not all the high-density samples possessed high magnetism. The SEM images and discussions are academically valuable since they clearly illustrate grain formation and morphology in the melt pool, areas where the literature provides limited discussion. Furthermore, this paper incorporates quantitative phase analyses, revealing that the magnetic properties increase with increasing volume fraction of the strong magnetic phase Nd2Fe14B. Another significant contribution of this paper is that it is the first study to investigate the effect of heated bed on L-PBF-NdFeB alloys. The density of the samples and Br can be improved with the use of elevated powder bed heating, while the Hc decreases. The (BH)max can also be improved from 55 to 84 kJ/m3 through elevated powder bed heating. The maximum magnetic properties obtained with the heated bed (400 °C) were as follows: Br, 0.76 T; Hci, 750 kA/m; and (BH)max, 84 kJ/m3
The onset of convection in horizontally partitioned porous layers
In this paper, the onset of convection in a horizontally partitioned porous layer is investigated. Two identical sublayers are separated by a thin impermeable barrier. There exists a background horizontal flow in one of the layers or, equivalently, flows of half that strength in each sublayer but in opposite directions. A linearised stability analysis is performed where the horizontal component of the disturbance is factored into separate Fourier modes, leaving an ordinary differential eigenvalue problem for the critical Darcy-Rayleigh number as a function of the wavenumber. The dispersion relation is derived and the neutral stability curves are obtained for a wide range of horizontal flow rates. The presence of the horizontal flow alters the morphology of the neutral curves from that which occurs when there is no flow and travelling modes may arise. We also determine the condition under which the most dangerous disturbance changes from a stationary mode to travelling mode. Some three-dimensional aspects are also considered. (C) 2011 American Institute of Physics. [doi:10.1063/1.3589864
Çok Kriterli Karar Verme Problemleri İçin Promethee Yöntemi ve Gaıa Düzlemiyle Görsel Analizler: Türkiye’de Bölgesel Sosyo-Ekonomik Gelişmişlik Düzeylerinin Belirlenmesi Üzerine Bir Uygulama
DergiPark: 326176trakyasobedIn this study, it is aimed to show the consistency of the results of PROMETHEE and GAIA Plane, one of the Multi Criteria Decision Making Methods and the applicability of these methods in the field of socio-economic development. For these purposes, it is realized to determine the level of socioeconomic development and to outrank the regions according to selected socioeconomic criteria. In this study 7 geographic regions are includedBu çalışmada, Çok Kriterli Karar Verme (ÇKKV) yöntemlerinden olan ve çeşitli alanlara uygulanan PROMETHEE yöntemi ve GAIA düzleminin tanıtılması, uygulanabilirliği ile bu yöntemle elde edilen sonuçların tutarlılığının gösterilmesi hedeflenmektedir. Bu hedef doğrultusunda sosyal ve ekonomik alanlardan seçilen değişkenler baz alınarak, bölgelerin sosyo-ekonomik gelişmişlik düzeylerinin belirlenmesi ve bu belirleme doğrultusunda sıralama işlemleri gerçekleştirilmiştir. Bu amaçlar doğrultusunda gerçekleştirilen çalışma mevcut idari yapı çerçevesinde 7 coğrafi bölgeyi kapsamaktadı
Children's Foreign Language Anxiety Scale: Preliminary Tests of Reliability and Validity
Foreign language anxiety (FLA), which constitutes a serious problem in the foreign language learning process, has been mainly seen as a research issue regarding adult language learners, while it has been overlooked in children. This is because there is a lack of appropriate tools to measure FLA among children, whereas there are many studies on the scales that aim to measure anxiety levels among adult learners. Thus, the current study aims to conduct the preliminary tests of reliability and validity of the Children's Foreign Language Anxiety Scale (CFLAS) and to report on the pilot examination of reliability, validity and factor structure of the CFLAS. The findings of the pilot study show that CFLAS is a reliable and valid tool to measure FLA levels among children who learn English as a foreign language (EFL) within the age range of 7-12 in a Turkish EFL context
Occurrence of anthrax in Kars district, Turkey.
The aims of the study were to determine the prevalence of anthrax by bacteriologic methods in cattle and sheep between January 2000 and September 2001 and to determine the distribution of this zoonotic disease in humans in Kars district, Turkey. Bacillus anthracis was isolated and identified in 34 out of 38 (91%) cattle and 11 out of 17 (64%) sheep samples obtained from organs suspected of anthrax. The records of the Governmental Health Branch showed that 89 cases of cutaneous anthrax were diagnosed in humans during the study periods in the same district
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