110 resultados para laser beam beyond the diffraction limits
Resumo:
We consider here how cultural and socioeconomic dimensions of justice beyond the state are related. First we examine cosmopolitan theories that have drawn on John Rawls's egalitarian liberal framework to argue that a just global order requires substantive, transnational redistribution of material resources. We then assess the view, ironically put forward by Rawls himself, that this perspective is ethnocentric and insufficiently tolerant of non-liberal cultures. We argue that Rawls is right to be concerned about the danger of ethnocentrism, but wrong to assume that this requires us to reject the case for substantive redistribution across state boundaries. A more compelling account of justice beyond the state will integrate effectively socioeconomic and cultural aspects of justice. We suggest that this approach is best grounded in a critical theory of recognition that responds to the damage caused to human relations by legacies of historical injustice.
Resumo:
Introduction
Much has been written about the impact of conflict on the physical nature of cities; most obviously perhaps the damage, destruction, defensive construction and spatial reconfigurations that evolve in times of conflict. Set within the context of Belfast, Northern Ireland, this paper will focus on three areas. First, a closer reading of the long-term physical impact of conflict, in particular, the spatial forms and practices that persist conceptually and culturally, and/or resist re-conceptualisation. Secondly, the effect of conflict on the nature of architectural practice itself, considering whether issues such as appointment and procurement impacted on architectural expectation and the context of operation. Thirdly, the effect of conflict on people, in particular in relation to creativity and hence the psyche of practice itself. This section will also identify the conditions that undermine or support design quality and creativity not only within times of conflict but also as society evolves out of the shadow space. 1
Twelve years on from the Peace Agreement,2 it may seem remarkable from an external perspective that Northern Ireland still needs to be reflecting on its troubled past. But the immediate post-conflict phase offered the communities of Northern Ireland place and time to experience ‘normal life’, begin to reconcile themselves to the hurt they experienced and start to reconfigure their relationships to one another. Indeed, it has often been expressed that probing the issues too much, at too early a phase, might in fact ‘Open old wounds without resolving anything’ and/or ‘Destabilise the already fragile political system.’3 This tendency not to deliberate or be too probing is therefore understandable and might be the reason why, for example, Northern Ireland's first Architecture and Built Environment policy, published in June, 2006, contains only one routine reference to ‘the Troubles’.
Clearly, however, there is a time in the development of a healthy, functioning society, when in order effectively to plan its future, it must also carry out a closer reading and deeper understanding of its past. As Maya Angelou puts it, ‘History, despite its wrenching pain/ Cannot be unlived, and if faced/ With courage, need not be lived again.’4
Increasingly, those within the creative arts sector and the built environment professions are showing interest in carrying out that closer reading, teasing out issues around conflict. This was led in part by the recent publication of the Troubles Archive by the Arts Council of Northern Ireland.5 Those involved in the academic or professional development of future generations of architects are also concerned about the relevance of a post-conflict condition. As a profession, if architects purport to be concerned with context, then the almost tangible socio-political circumstances and legacy of Northern Ireland does inevitably require direct eye contact. This paper therefore aims to bring the relationship between conflict and architectural practice in Northern Ireland into sharp focus, not to constrain or dull creative practice but to heighten its potential.
Resumo:
In a recent paper [Phys. Rev. Lett. 88, 163202 (2002)] we established the threshold behavior of the cross section of positron-atom annihilation into two gamma quanta near the positronium (Ps)-formation threshold. Here, the near-threshold behavior of the positron 3 gamma annihilation cross section and its relation to the ortho-Ps-formation cross section are determined. We also analyze the feasibility of observing these effects by examining the effect of the ?nite-energy resolution of a positron beam on the threshold behavior.
Resumo:
We characterize the structural transitions in an initially homeotropic bent-rod nematic liquid crystal excited by ac fields of frequency f well above the dielectric inversion point f(i). From the measured principal dielectric constants and electrical conductivities of the compound, the Carr-Helfrich conduction regime is anticipated to extend into the sub-megahertz region. Periodic patterned states occur through secondary bifurcations from the Freedericksz distorted state. An anchoring transition between the bend Freedericksz (1317) and degenerate planar (DP) states is detected. The BF state is metastable well above the Freedericksz threshold and gives way to the DP state, which persists in the field-off condition for several hours. Numerous +1 and -1 umbilics form at the onset of BF distortion, the former being largely of the chiral type. They survive in the DP configuration as linear defects, nonsingular in the core. In the BF regime, not far from fi, periodic Williams-like domains form around the umbilics; they drift along the director easy axis right from their onset. With increasing f, the wave vector of the periodic domains switches from parallel to normal disposition with respect to the c vector. Well above fi, a broadband instability is found.
Resumo:
We report on the electric-field-generated effects in the nematic phase of a twin mesogen formed of bent-core and calamitic units, aligned homeotropically in the initial ground state and examined beyond the dielectric inversion point. The bend-Freedericksz (BF) state occurring at the primary bifurcation and containing a network of umbilics is metastable; we focus here on the degenerate planar (DP) configuration that establishes itself at the expense of the BF state in the course of an anchoring transition. In the DP regime, normal rolls, broad domains, and chevrons (both defect-mediated and defect-free types) form at various linear defect-sites, in different regions of the frequency-voltage plane. A significant novel aspect common to all these patterned states is the sustained propagative instability, which does not seem explicable on the basis of known driving mechanisms.
Resumo:
We examined the relationship between Individualism/Collectivism and generalized social trust across 31 European nations participating in the European Social Survey. Using multi-level regression analyses, the current study provides the first empirical investigation of the effects of cultural norms of Individualism/Collectivism on generalized social trust while accounting for individuals' own cultural orientations within the same analysis. The results provide clear support for Yamagishi and Yamagishi (1994) emancipation theory of trust, showing a significant and positive relationship between Individualism/Collectivism and generalized social trust, over and above the effect of a country political history of communism and ethnic heterogeneity. Having controlled for individual effects of Individualism/Collectivism it is clear that the results of the current analysis cannot be reduced to an individual-level explanation, but must be interpreted within the context Of macrosocial processes. We conclude by discussing potential mechanisms that could explain why national individualism is more likely to foster trust among people than collectivism.