998 resultados para Réseau local de télécommunications
Resumo:
We address the distribution of quantum information among many parties in the presence of noise. In particular, we consider how to optimally send to m receivers the information encoded into an unknown coherent state. On one hand, a local strategy is considered, consisting in a local cloning process followed by direct transmission. On the other hand, a telecloning protocol based on nonlocal quantum correlations is analysed. Both the strategies are optimized to minimize the detrimental effects due to losses and thermal noise during the propagation. The comparison between the local and the nonlocal protocol shows that telecloning is more effective than local cloning for a wide range of noise parameters. Our results indicate that nonlocal strategies can be more robust against noise than local ones, thus being suitable candidates for playing a major role in quantum information networks.
Resumo:
Background: Primary chemotherapy is being given in the treatment of large and locally advanced breast cancers, but a major concern is local relapse after therapy. This paper has examined patients treated with primary chemotherapy and surgery (either breast-conserving surgery or mastectomy) and has examined the role of factors which may indicate those patients who are subsequently more likely to experience local recurrence of,disease.
Methods: A consecutive series of 173 women, with data available for 166 of these, presenting with large and locally advanced breast cancer (T2 >4 cm, T3, T4, or N2) were treated with primary chemotherapy comprising cyclophosphamide, vincristine, doxorubicin, and prednisolone and then surgery (either conservation or mastectomy with axillary surgery) followed by radiotherapy were examined.
Results: The clinical response rate of these patients was 75% (21% complete and 54% partial), with a complete pathological response rate of 15%. A total of 10 patients (6%) experienced local disease relapse, and the median time to relapse was 14 months (ranging from 3 to 40). The median survival in this group was 27 months (ranging from 13 to 78). In patients having breast conservation surgery, local recurrence occurred in 2%, and in those undergoing mastectomy 7% experience local relapse of disease. Factors predicting patients most likely to experience local recurrence were poor clinical response and residual axillary nodal disease after chemotherapy.
Conclusions: Excellent local control of disease can be achieved in patients with large and locally advanced breast cancers using a combination of primary chemotherapy, surgery and radiotherapy. However, the presence of residual tumor in the axillary lymph nodes after chemotherapy is a predictor of local recurrence and patients with a better clinical response were also less likely to experience local disease recurrence. The size and degree of pathological response did not predict patients most likely to experience recurrence of disease. (C) 2003 Excerpta Medica, Inc. All rights reserved.
Resumo:
In this study, contributions of both local steric and remote baroclinic effects (i.e., steric variations external to the region of interest) to the inter-annual variability of winter sea level in the North Sea, with respect to the North Atlantic Oscillation (NAO), for the period of 1953–2010 are investigated. On inter-annual time scales in this period, the NAO is significantly correlated to sea level variations in the North Sea only in the winter months (December–March), while its correlation to sea temperature over much of the North Sea is only significant in January and February. The discrepancy in sea level between observations and barotropic tide and surge models forced by tides and local atmospheric forcing, i.e., local atmospheric pressure effects and winds, in the present study are found to be consistent with previous studies. In the North Sea, local thermosteric effects caused by thermal expansion play a minor role on winter-mean NAO related sea level variability compared with atmospheric forcing. This is particularly true in the southeastern North Sea where water depths are mostly less than 25 m. Our calculations demonstrate that the discrepancy can be mostly explained by remote baroclinic effects, which appear as water mass exchanges on the continental shelf and are therefore only apparent in ocean bottom pressure. In the North Sea, NAO related sea level variations seem to be a hybrid of barotropic and baroclinic processes. Hence, they can only be adequately modelled with three-dimensional baroclinic ocean models that include contributions of baroclinic effects and large-scale atmospheric forcing external to the region of interest.
Resumo:
Clinical epidemiological studies have revealed relatively weak, yet statistically significant, associations between dyslipidemia/dyslipoproteinemia and diabetic retinopathy (DR). Recent large interventional studies, however, demonstrated an unexpectedly robust efficacy of fenofibrate on the development of DR, possibly independent of plasma lipids. To unify the apparent discrepancies, we hypothesize that plasma lipoproteins play an indirect but important role in DR, contingent on the integrity of the blood-retina-barrier (BRB). In retinas with an intact BRB, plasma lipoproteins may be largely irrelevant; however, important effects become operative after the BRB is impaired in diabetes, leading to lipoprotein extravasation and subsequent modification, hence toxicity to the neighbouring retinal cells. In this hypothesis, BRB leakage is the key, plasma lipoprotein concentrations mainly modulate its consequences, and fenofibrate has intra-retinal actions. This review summarizes our current knowledge of the direct effects and mechanisms of modified lipoproteins on retinal cells and their potential contribution to the pathogenesis of DR.
Resumo:
The member states of the European Union are faced with the challenges of handling “big data” as well as with a growing impact of the supranational level. Given that the success of efforts at European level strongly depends on corresponding national and local activities, i.e., the quality of implementation and the degree of consistency, this chapter centers upon the coherence of European strategies and national implementations concerning the reuse of public sector information. Taking the City of Vienna’s open data activities as an illustrative example, we seek an answer to the question whether and to what extent developments at European level and other factors have an effect on local efforts towards open data. We find that the European Commission’s ambitions are driven by a strong economic argumentation, while the efforts of the City of Vienna have only very little to do with the European orientation and are rather dominated by lifestyle and administrative reform arguments. Hence, we observe a decoupling of supranational strategies and national implementation activities. The very reluctant attitude at Austrian federal level might be one reason for this, nationally induced barriers—such as the administrative culture—might be another. In order to enhance the correspondence between the strategies of the supranational level and those of the implementers at national and regional levels, the strengthening of soft law measures could be promising.
Resumo:
Manipulator motion planning is a classic problem in robotics, with a number of complete solutions available for their motion in controlled (industrial) environments. Owing to recent technological advances in the field of robotics, there has been a significant development of more complex robots with high-fidelity sensors and more computational power. One such example has been a rise in the production of humanoid robots equipped with dual-arm manipulators which require complex motion planning algorithms. Also, the technological advances have resulted in a shift from using manipulators in strictly controlled environments, to investigating the deployment of manipulators in dynamic or unknown environments. As a result, a greater emphasis has been put on the development of local motion planners, which can provide real-time solutions to these problems. Artificial Potential Fields (APFs) is one such popular local motion planning technique, which can be applied to manipulator motion planning, however, the basic algorithm is severely prone to local minima problems. Here, two modified APF-based strategies for solving the dual-arm motion planning task in unknown environments are proposed. Both techniques make use of configuration sampling and subgoal selection to assist the APFs in avoiding these local minima scenarios. Extensive simulation results are presented to validate the efficacy of the proposed methodology.
Resumo:
Northern Ireland is emerging from violence but still living with conflict. The recent flags protests in Belfast represent a challenge to public administration to transcend the contested politics of local government in Northern Ireland and to navigate a way through a symbolic legacy issue. This article draws on a longitudinal hermeneutic analysis of empirical research conducted on Northern Ireland local government over a decade, where these concerns dominated much debate. Additional analysis of the research findings reveals broader problems applicable to any public administration faced with managing situations in which good governance in public participation and procedural correctness operates alongside fundamental political disagreement and distrust. These conclusions are particularly pertinent for local administrations in societies transitioning from conflict.
Resumo:
This article examines the difficulties of finding local solutions to the problem of contentious events in contemporary Northern Ireland. In so doing, it offers a sociological perspective on fundamental divisions in Northern Ireland: between classes and between communities. It shows how its chosen case study—parades and associated protests in north Belfast—exemplifies the most fundamental problem that endures in post-Agreement Northern Ireland, namely that political authority is not derived from a common civic culture (as is the norm in Western liberal democracy) but rather that legitimacy is still founded on the basis of the culture of either one or the other community. Haugaard’s reflections on authority and legitimacy are used to explore Northern Ireland’s atypical experience of political conflict vis-`a-vis the Western liberal democratic model. The Bourdieusian concepts of field illusio and doxa help to explain why it is that parading remains such an important political and symbolic touchstone in this society.