825 resultados para OPC DA and AE clients
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Context. Classical supergiant X-ray binaries (SGXBs) and supergiant fast X-ray transients (SFXTs) are two types of high-mass X-ray binaries (HMXBs) that present similar donors but, at the same time, show very different behavior in the X-rays. The reason for this dichotomy of wind-fed HMXBs is still a matter of debate. Among the several explanations that have been proposed, some of them invoke specific stellar wind properties of the donor stars. Only dedicated empiric analysis of the donors’ stellar wind can provide the required information to accomplish an adequate test of these theories. However, such analyses are scarce. Aims. To close this gap, we perform a comparative analysis of the optical companion in two important systems: IGR J17544-2619 (SFXT) and Vela X-1 (SGXB). We analyze the spectra of each star in detail and derive their stellar and wind properties. As a next step, we compare the wind parameters, giving us an excellent chance of recognizing key differences between donor winds in SFXTs and SGXBs. Methods. We use archival infrared, optical and ultraviolet observations, and analyze them with the non-local thermodynamic equilibrium (NLTE) Potsdam Wolf-Rayet model atmosphere code. We derive the physical properties of the stars and their stellar winds, accounting for the influence of X-rays on the stellar winds. Results. We find that the stellar parameters derived from the analysis generally agree well with the spectral types of the two donors: O9I (IGR J17544-2619) and B0.5Iae (Vela X-1). The distance to the sources have been revised and also agree well with the estimations already available in the literature. In IGR J17544-2619 we are able to narrow the uncertainty to d = 3.0 ± 0.2 kpc. From the stellar radius of the donor and its X-ray behavior, the eccentricity of IGR J17544-2619 is constrained to e< 0.25. The derived chemical abundances point to certain mixing during the lifetime of the donors. An important difference between the stellar winds of the two stars is their terminal velocities (ν∞ = 1500 km s-1 in IGR J17544-2619 and ν∞ = 700 km s-1 in Vela X-1), which have important consequences on the X-ray luminosity of these sources. Conclusions. The donors of IGR J17544-2619 and Vela X-1 have similar spectral types as well as similar parameters that physically characterize them and their spectra. In addition, the orbital parameters of the systems are similar too, with a nearly circular orbit and short orbital period. However, they show moderate differences in their stellar wind velocity and the spin period of their neutron star which has a strong impact on the X-ray luminosity of the sources. This specific combination of wind speed and pulsar spin favors an accretion regime with a persistently high luminosity in Vela X-1, while it favors an inhibiting accretion mechanism in IGR J17544-2619. Our study demonstrates that the relative wind velocity is critical in class determination for the HMXBs hosting a supergiant donor, given that it may shift the accretion mechanism from direct accretion to propeller regimes when combined with other parameters.
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From the Introduction. It is not frequent for a National Regulation Authority (NRA) to bring an action against the Commission decision and, cynically speaking, case Prezes Urzędu Komunikacji Elektronicznej2 v Commission3 shows that the avoidance of a sweeping retaliation may be one of the reasons for it. The General Court followed the Commission‟s argument that, notwithstanding the peculiarities of the employment conditions of the Polish Regulator‟s legal counsel giving it virtually full independence, as well as the fact that the Polish law itself does not differentiate between in-house counsel and third party attorneys, the claim should be rejected on the grounds of inadmissibility. The GC based its judgment on Art 19 of the Statute of the Court of Justice4, which requires that, with the exception of the Member States' Governments and the EU Institutions, parties to the dispute must be represented by a lawyer. In so doing, the Court explicitly referred to the infamous Akzo Nobel Chemicals and Akcros Chemicals v Commission5 and EREF v Commission6. Most importantly, the Court stated that the lawyers representing Prezes Urzędu Komunikacji Elektronicznej (UKE) are bound to enjoy a degree of independence inferior to that of lawyers who are not linked to their clients by an employment contract7.
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The goal of this publication is to attempt to assess the thirteen years (2001- -2014) of the West’s military presence in the countries of post-Soviet Central Asia, closely associated with the ISAF and OEF-A (Operation Enduring Freedom – Afghanistan) missions in Afghanistan. There will also be an analysis of the actual challenges for the region’s stability after 2014. The current and future security architecture in Central Asia will also be looked at closely, as will the actual capabilities to counteract the most serious threats within its framework. The need to separately handle the security system in Central Asia and security as such is dictated by the particularities of political situation in the region, the key mechanism of which is geopolitics understood as global superpower rivalry for influence with a secondary or even instrumental role of the five regional states, while ignoring their internal problems. Such an approach is especially present in Russia’s perception of Central Asia, as it views security issues in geopolitical categories. Because of this, security analysis in the Central Asian region requires a broader geopolitical context, which was taken into account in this publication. The first part investigates the impact of the Western (primarily US) military and political presence on the region’s geopolitical architecture between 2001 and 2014. The second chapter is an attempt to take an objective look at the real challenges to regional security after the withdrawal of the coalition forces from Afghanistan, while the third chapter is dedicated to analysing the probable course of events in the security dimension following 2014. The accuracy of predictions time-wise included in the below publication does not exceed three to five years due to the dynamic developments in Central Asia and its immediate vicinity (the former Soviet Union, Afghanistan, Pakistan, Iran), and because of the large degree of unpredictability of policies of one of the key regional actors – Russia (both in the terms of its activity on the international arena, and its internal developments).
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In Kazakhstan doctoral students are not expected to make a contribution to knowledge, as is required at Western universities. Rather, their task is to become familiar with what is known and then make policy recommendations for Kazakhstan. For example, how can the human capital in Kazakhstan be improved? This is a very broad subject for a PhD dissertation. However, it does require a holistic perspective, and such dissertation topics may create an opportunity for systems scientists. When Russell Ackoff created the Social Systems Sciences PhD program at the Wharton School of the University of Pennsylvania, he had his students solve practical problems for business or government managers. That program graduated a large number of people who became consultants. A few became academics in several countries. The program created a philosophy and methods for holistic management. Large issues in developing countries may be a source of clients for systems scientists who want to further develop philosophy, theories and methods by working with large social systems.
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The current chemotherapeutic treatment of alveolar echinococcosis (AE) in humans is based on albendazole and/or mebendazole. However, the costs of treatment, life-long consumption of drugs, parasitostatic rather than parasiticidal activity of chemotherapy, and high recurrence rates after treatment interruption warrant more efficient treatment options. Experimental treatment of mice infected with Echinococcus multilocularis metacestodes with fenbendazole revealed similar efficacy to albendazole. Inspection of parasite tissue from infected and benzimidazole-treated mice by transmission electron microscopy (TEM) demonstrated drug-induced alterations within the germinal layer of the parasites, and most notably an almost complete absence of microtriches. On the other hand, upon in vitro exposure of metacestodes to benzimidazoles, no phosphoglucose isomerase activity could be detected in medium supernatants during treatment with any of these drugs, indicating that in vitro treatment did not severely affect the viability of metacestode tissue. Corresponding TEM analysis also revealed a dramatic shortening/retraction of microtriches as a hallmark of benzimidazole action, and as a consequence separation of the acellular laminated layer from the cellular germinal layer. Since TEM did not reveal any microtubule-based structures within Echinococcus microtriches, this effect cannot be explained by the previously described mechanism of action of benzimidazoles targeting β-tubulin, thus benzimidazoles must interact with additional targets that have not been yet identified. In addition, these results indicate the potential usefulness of fenbendazole for the chemotherapy of AE.
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Subtype polymorphism is a cornerstone of object-oriented programming. By hiding variability in behavior behind a uniform interface, polymorphism decouples clients from providers and thus enables genericity, modularity and extensi- bility. At the same time, however, it scatters the implementation of the behavior over multiple classes thus potentially hampering program comprehension. The extent to which polymorphism is used in real programs and the impact of polymorphism on program comprehension are not very well understood. We report on a preliminary study of the prevalence of polymorphism in several hundred open source software systems written in Smalltalk, one of the oldest object-oriented programming languages, and in Java, one of the most widespread ones. Although a large portion of the call sites in these systems are polymorphic, a majority have a small number of potential candidates. Smalltalk uses polymorphism to a much greater extent than Java. We discuss how these findings can be used as input for more detailed studies in program comprehension and for better developer support in the IDE.
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Mode of access: Internet.
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"March 1996."
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Mode of access: Internet.
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Mode of access: Internet.
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"Ces Notes ... ont été publiées déjà sur ce nom dans la Technique automobile et aérienne."
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Mode of access: Internet.
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Mode of access: Internet.