123 research outputs found

    Magnetospheric particle acceleration and X-ray emission of pulsars

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    The available data on isolated X-ray pulsars, their wind nebulae, and the supernova remnants which are connected to some of these sources are analyzed. It is shown that electric fields of neutron stars tear off charged particles from the surface of neutron star and trigger the acceleration of particles. The charged particles are accelerated mainly in the field of magneto-dipole radiation wave. Power and energy spectra of the charged particles depend on the strength of the magneto-dipole radiation. Therefore, the X-ray radiation is strongly dependent on the rate of rotational energy loss and weakly dependent on the electric field intensity. Coulomb interaction between the charged particles is the main factor for the energy loss and the X-ray spectra of the charged particles.Comment: minor correction on table format, 20 pages (4 figures, 1 table), submitted to International Journal of Modern Physics

    Effects of the background radiation on radio pulsar and supernova remnant searches and the birth rates of these objects

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    In different directions of the Galaxy the Galactic background radio radiation and radiation of complex star formation regions which include large number of OB associations have different influences on radio pulsar (PSR) and supernova remnant (SNR) searches. In this work we analyse the effects of these background radiations on the observations of PSRs at 1400 MHz and SNRs at 1000 MHz. In the interval l=0o^o±60o\pm60^o the PSRs with flux F1400_{1400}>>0.2 mJy and the SNRs with surface brightness Σ\Sigma>1021>10^{-21} Wm2^{-2}Hz1^{-1}sr1^{-1} are observable for all values of l and b. All the SNRs with Σ\Sigma>3×1022>3\times10^{-22} Wm2^{-2}Hz1^{-1}sr1^{-1} can be observed in the interval 60o^o<<l<300o<300^o. We have examined samples of PSRs and SNRs to estimate the birth rates of these objects in the region up to 3.2 kpc from the Sun and also in the Galaxy. The birth rate of PSRs is about one in 200 years and the birth rate of SNRs is about one in 65 years in our galaxy.Comment: revised versio

    Patterns in SNMP-Based Management

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    A lot of activity is currently going on to replace the SNMP management architecture with a solution better suited to managing modern IP networks and systems. New candidates include Management by delegation, active networks, and Web-based management. In this exercise, the management community runs the risk of throwing the baby out with the bath water by focusing too much on a few well-known problems exhibited by SNMP (e.g., its poor scalability) and neglecting most of its other characteristics, including those that contributed to its success (e.g., the reasons why it is simple). One way to avoid this is to explicitly capture the experience gained in the management of IP networks and systems with SNMP. In this paper, we make one step in this direction by studying the SNMP management architecture through a software engineer s eyes: we identify in SNMP some of the fundamental architectural and design patterns defined in the literature. Patterns are schematic, proven solutions to recurring problems. By characterizing the current management architecture in terms of patterns, we help retain the strengths of SNMP-based management in future management architectures. We also make it easier for new software engineers to move to network and systems management by characterizing this application domain in standard pattern terms, as opposed to using the jargon understood solely by the SNMP community

    Heritage language anxiety and majority language anxiety among Turkish immigrants in the Netherlands

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    Aims and objectives: This study examines the language anxiety that occurs in immigrants’ daily lives when speaking the heritage language and the majority language, both in their host country and during visits to their home country. It compares the levels of heritage language anxiety and majority language anxiety across three generations of the Turkish immigrant community in the Netherlands and explores the link between immigrants’ language anxiety, and sociobiographical (i.e. generation, gender, education) and language background variables (i.e. age of acquisition, self-perceived proficiency, frequency of language use). Design: A Likert scale-based questionnaire was administered to 116 participants across three generations who reported their language anxiety levels when speaking the heritage language and the majority language in three social contexts (i.e. family, friendship and speaking with native speakers). Findings: Statistical analyses revealed that heritage language anxiety and majority language anxiety were prevalent in immigrants’ daily life, and that levels of both forms of anxiety differed across generations, and in different daily life situations. First- and second-generation immigrants typically experienced majority language anxiety, while second- and predominantly third-generation immigrants suffered from heritage language anxiety. Relationships emerged between language background variables and both forms of anxiety, but only in certain situations. These findings suggest that language background variables on their own may be insufficient to explain immigrant language anxiety in certain social contexts (i.e. within family). Rather than merely language background factors, a variety of other issues within social, cultural and national currents must be considered when examining language anxiety in the immigrant context. Implications: Taking an interdisciplinary approach that combines language contact and foreign language anxiety/second language anxiety research, this study suggests that the concept of foreign language anxiety/second language anxiety should be expanded beyond the confines of the classroom in order to include daily interactions immigrant or minority communities. Originality: This study contributes to the limited body of evidence on the topic of language anxiety in immigrant contexts and presents a new construct ‘majority language anxiety’

    Femoral nerve compression secondary to a ganglion cyst arising from a hip joint: a case report and review of the literature

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    <p>Abstract</p> <p>Introduction</p> <p>Femoral nerve compression due to a cystic lesion around the hip joint is rare and only a few cases have been described in the literature. Among these, true ganglion cysts are even more rare.</p> <p>Case presentation</p> <p>We report the case of a 57-year-old woman with femoral nerve compression caused by a true ganglion cyst of the hip joint.</p> <p>Conclusion</p> <p>A high index of suspicion is required to predict a non-palpable cystic lesion around the hip joint as it may mimic different disorders and should be kept in mind in the differential diagnosis of unusual groin pain, radicular pain and peripheral vascular disorders.</p

    Lack of association between RNASEL Arg462Gln variant and the risk of breast cancer

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    Background: The RNASEL G1385A variant was recently found to be implicated in the development of prostate cancer. Considering the function of RNase L and the pleiotropic effects of mutations associated with cancer, we sought to investigate whether the RNASEL G1385A variant is a risk factor for breast cancer. Patients and Methods: A total of 453 breast cancer patients and 382 age- and sex-matched controls from Greece and Turkey were analyzed. Genotyping for the RNASEL G1385A variant was performed using an Amplification Refractory Mutation System (ARMS). Results: Statistical evaluation of the RNASEL G1385A genotype distribution among breast cancer patients and controls revealed no significant association between the presence of the risk genotype and the occurrence of breast cancer. Conclusion: Although an increasing number of studies report an association between the RNASEL G1385A variant and prostate cancer risk, this variant does not appear to be implicated in the development of breast cancer

    Sevinç, E

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