980 research outputs found

    A Study on anisotropy of cosmic ray distribution with a small array of water-cherenkov detectors

    Full text link
    The study of the anisotropy of the arrival directions is an essential tool to investigate the origin and propagation of cosmic rays primaries. A simple way of recording many cosmic rays is to record coincidences between a number of detectors. We have monitored multi-TeV cosmic rays by a small array of water cherenkov detectors in Tehran(35 43 N, 51 20 E, 1200m a.s.l). More than 1.1*10^6 extensive air shower events were recorded. In addition to the Compton- Getting effect due to the motion of the earth in the Galaxy, an anisotropy has been observed which is due to a unidirectional anisotropy of cosmic ray flow along the Galactic arms.Comment: 16 pages 9 figs and one tabl

    Estimation of N-acetyltransferase 2 haplotypes

    Get PDF
    N-Acetyltransferase 2 (NAT2) genotyping may result in a considerable percentage in several ambiguous allele combinations. PHASE 2.1 is a statistical program which is designed to estimate the probability of different allele combinations. We have investigated haplotypes of 2088 subjects genotyped for NAT2 according to standard PCR/RFLP methods. In 856 out of 2088 cases the genotype was clearly defined by PCR/RFLP only. In many of the remaining cases the program clearly defined the most probable allele combination: In the case of *5A/*6C, *5B/*6A the probability for *5B/*6A is 99% whereas the alternative allele combination *5A/*6C can be neglected. Other combinations cannot be allocated with a comparable high probability. For example the allele combination *5A/*5C, *5B/*5D provides for *5A/*5C a probability of 69% whereas the estimation for *5B/*5D allele is only 31%. In the two most often observed constellations in our data [(*12A/*5B, *12C/*5C); (*12A/*6A, *12B/*6B, *4/*6C)] the probability of allele combination was ascertained as follows: *12A/*5B, 98%; *12C/*5C, 1.4% and *12A/*6A, 82%; *4/*6C, 17%; *12B/*6B, 0%. The estimation of the NAT2 haplotype is important because the assignment of the NAT2 alleles *12A, *12B or *13 as a rapid or slow genotype has been discussed controversially. Otherwise the classification of alleles in subjects which are not showing a clearly allocation can result in a rapid or slow acetylation state. This assignment has an important role in survey of bladder cancer cases in the scope of occupational exposure with aromatic amines. --PHASE 2.1,NAT2 genotyping,single nucleotide polymorphism

    Effects of Selenium Supplementation on Gene Expression Levels of Inflammatory Cytokines and Vascular Endothelial Growth Factor in Patients with Gestational Diabetes

    Get PDF
    Selenium is known to exert multiple beneficial effects including anti-inflammatory actions. The aim of the study was to evaluate the effects of selenium supplementation on gene expression levels of inflammatory cytokines and vascular endothelial growth factor (VEGF) in women with gestational diabetes (GDM). This randomized double-blind, placebo-controlled trial was carried out among 40 subjects diagnosed with GDM aged 18–40 years old. Subjects were randomly allocated into two groups to receive either 200 μg/day selenium supplements (n = 20) or placebo (n = 20) for 6 weeks. Gene expression of inflammatory cytokines and VEGF were assessed in lymphocytes of GDM women with RT-PCR method. Results of RT-PCR indicated that after the 6-week intervention, compared with the placebo, selenium supplementation downregulated gene expression of tumor necrosis factor alpha (TNF-α) (P = 0.02) and transforming growth factor beta (TGF-β) (P = 0.01), and upregulated gene expression of VEGF (P = 0.03) in lymphocytes of patients with GDM. There was no statistically significant change following supplementation with selenium on gene expression of interleukin (IL)-1β and IL-8 in lymphocytes of subjects with GDM. Selenium supplementation for 6 weeks in women with GDM significantly decreased gene expression of TNF-α and TGF-β, and significantly increased gene expression of VEGF, but did not affect gene expression of IL-1β and IL-8

    The TIGRE gamma-ray telescope

    Get PDF
    TIGRE is an advanced telescope for gamma-ray astronomy with a few arcmin resolution. From 0.3 to 10 MeV it is a Compton telescope. Above 1 MeV, its multi-layers of double sided silicon strip detectors allow for Compton recoil electron tracking and the unique determination for incident photon direction. From 10 to 100 MeV the tracking feature is utilized for gamma-ray pair event reconstruction. Here we present TIGRE energy resolutions, background simulations and the development of the electronics readout system

    Concepts and Dimensions in Continuous Midwifery Care Models Based on the Experiences and Expectations of Stakeholders: A Meta-Synthesis

    Get PDF
    Context: Pregnant women’s have access to different models of care especially to those who provide continuous care and this is one of the recommendations of the world health organization (WHO) for promoting maternal health. Moreover, to provide adequate services in care models, the experiences and perceptions of mothers, providers of prenatal care, and other stakeholders should be taken into consideration. Objectives: A systematic meta-synthesis was carried out to inquire into the findings of some qualitative studies aimed to explore the concept and dimensions of continuous midwifery care including experiences, perspectives and perceptions of engaged people. Data Sources: This study was the first step of an action research designed to develop a midwifery model of care. Qualitative research articles published between 2005 and 2015 on experiences, attitudes, expectations and opinions of stakeholders in models of midwifery care were collected from Google scholar, Elsevier, and PubMed databases. Study Selection: Following the various stages of the scrutiny of the abstracts and contents of the collected articles, five faculty members finally selected 21 qualitative research articles as eligible for inclusion in the meta-synthesis. Results: The findings of meta-synthesis showed that continuous midwifery care for pregnantwomenas a highly important process revolves around at least five basic themes: continuity of care, compliance with needs satisfaction levels, regulation of care environment, and the philosophy of providing continuous care. Conclusions: Given the importance of access to healthcare as a right for pregnant women and given the key role of continuous midwifery care in health promotion and maternal satisfaction, it is suggested based on the results of the study that rigorous local and national research in this area to be carried out so that adequate models of continuous midwifery care can be designed and implemented based on the findings

    Primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphomas: reappraisal of a provisional entity in the 2016 WHO classification of cutaneous lymphomas.

    Get PDF
    Primary cutaneous CD8-positive aggressive epidermotropic T-cell lymphoma is a rare and poorly characterized variant of cutaneous lymphoma still considered a provisional entity in the latest 2016 World Health Organization Classification of Cutaneous lymphomas. We sought to better characterize and provide diagnostic and therapeutic guidance of this rare cutaneous lymphoma. Thirty-four patients with a median age of 77 years (range 19-89 years) presented primarily with extensive annular necrotic plaques or tumor lesions with frequent mucous membrane involvement. The 5-year survival was 32% with a median survival of 12 months. A subset of 17 patients had a prodrome of chronic patches prior to the development of aggressive ulcerative lesions. We identified cases with lack of CD8 or αβ T-cell receptor expression yet with similar clinical and pathological presentation. Allogeneic stem cell transplantation provided partial or complete remissions in 5/6 patients. We recommend the term primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphoma as this more broad designation better describes this clinical-pathologic presentation, which allows the inclusion of cases with CD8 negative and/or αβ/γδ T-cell receptor chain double-positive or double-negative expression. We have identified early skin signs of chronic patch/plaque lesions that are often misdiagnosed as eczema, psoriasis, or mycosis fungoides. Our experience confirms the poor prognosis of this entity and highlights the inefficacy of our standard therapies with the exception of allogeneic stem cell transplantation in selected cases

    A self-adaptive cohesive zone model for interfacial delamination

    Get PDF
    Interfacial failure in the form of delamination, often results in malfunction or failure of laminated structures. Different numerical approaches have been proposed for the simulation of this process. Due to the appealing feature of predicting both the delamination onset and its growth, cohesive zone models have been widely used to simulate delamination as a result of a gradual degradation of the adhesion between two materials when they become separated. Application of cohesive zone models for the modelling of delamination in brittle interfaces in a quasi-static finite element framework suffers froman intrinsic discretization sensitivity. A large number of interface elements are needed for the discretization of the process zone of a cohesive crack. Otherwise, a sudden release of energy in large cohesive zone elements results in a sequence of snap-through or snap-back points to appear in the global load-displacement response of the system which compromises the numerical efficiency. While computationally expensive path-following techniques can be used to follow the oscillatory path, the efficiency and robustness of brittle cohesive zone models can be significantly increased by reducing the oscillations observed in the global load-displacement behaviour without a further mesh refinement. In line with this purpose, the separation approximation in the process zone is enriched with an adaptive hierarchical extension. The linear separation approximation throughout the cohesive zone element is enriched with a bi-linear function, where the enrichment peak position and the magnitude of the enrichment are regarded as additional degrees of freedom obtained by minimization of the total potential of the global system. The mobility of the peak of the enrichment function within individual cohesive zone elements locally adapts the discretization to the physics governing the problem. Important numerical aspects of the proposed enrichment strategy such as its mobility and uniqueness have been thoroughly investigated while its limitations are addressed. The efficiency and robustness of the enrichment are shown through numerical examples which prove the general applicability of the methodology. In fact, application of the elaborated enrichment eliminates the need for a further mesh refinement while keeping the standard Newton-Raphson approach applicable in the case of a relatively coarse mesh which saves considerable computational costs. Extension of the proposed enrichment scheme to delamination in a threedimensional finite element framework has been carried out as well. Planar interix face elements have been enriched along all edges by bi-linear functions with mobile peaks. The effect of the proposed methodology on reducing discretization-induced oscillations is quantitatively evaluated. To deal with planar crack growth where the crack front is oblique with respect to element edges, a non-hierarchical enrichment strategy is also developed and its performance is compared with its hierarchical counterpart. The self-adaptive finite element formulation is extended to a framework suitable for large deformations and is applied to interfaces in microelectronics under realistic mixed-mode loading conditions. In particular, the material/interface systems used in miniaturized mixed-mode bending tests, which are conducted for a wide range of mode angles, are modelled to make a direct comparison with experimental results. The interface constitutive lawthat is used takes the dependence of fracture toughness on mode-mixity into account. Thereby, the enhanced cohesive zone model can be used for the simulation of the behaviour of brittle interfaces in an accurate, effective, and efficient manner

    Synthesizing Iterators from Abstraction Functions

    Get PDF
    A technique for synthesizing iterators from declarative abstraction functions written in a relational logic specification language is described. The logic includes a transitive closure operator that makes it convenient for expressing reachability queries on linked data structures. Some optimizations, including tuple elimination, iterator flattening, and traversal state reduction, are used to improve performance of the generated iterators. A case study demonstrates that most of the iterators in the widely used JDK Collections classes can be replaced with code synthesized from declarative abstraction functions. These synthesized iterators perform competitively with the hand-written originals. In a user study the synthesized iterators always passed more test cases than the hand-written ones, were almost always as efficient, usually took less programmer effort, and were the qualitative preference of all participants who provided free-form comments
    corecore