63,576 research outputs found

    Disability and Employer Practices: Research Across the Disciplines

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    [Excerpt] This book has three related purposes: To raise the visibility of the critical issues surrounding equitable employment for people with disabilities, with a focus on workplace policies and practices. To provide evidence of the importance of applying the very best science available to address these issues across all facets of the problem. To illustrate how combining scientific efforts from the different disciplines to work closely on a common purpose, as well as the intimate involvement of key stakeholders, can provide extraordinary results that inform needed changes to policy and practice

    Universal Protocols for Information Dissemination Using Emergent Signals

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    We consider a population of nn agents which communicate with each other in a decentralized manner, through random pairwise interactions. One or more agents in the population may act as authoritative sources of information, and the objective of the remaining agents is to obtain information from or about these source agents. We study two basic tasks: broadcasting, in which the agents are to learn the bit-state of an authoritative source which is present in the population, and source detection, in which the agents are required to decide if at least one source agent is present in the population or not.We focus on designing protocols which meet two natural conditions: (1) universality, i.e., independence of population size, and (2) rapid convergence to a correct global state after a reconfiguration, such as a change in the state of a source agent. Our main positive result is to show that both of these constraints can be met. For both the broadcasting problem and the source detection problem, we obtain solutions with a convergence time of O(log2n)O(\log^2 n) rounds, w.h.p., from any starting configuration. The solution to broadcasting is exact, which means that all agents reach the state broadcast by the source, while the solution to source detection admits one-sided error on a ε\varepsilon-fraction of the population (which is unavoidable for this problem). Both protocols are easy to implement in practice and have a compact formulation.Our protocols exploit the properties of self-organizing oscillatory dynamics. On the hardness side, our main structural insight is to prove that any protocol which meets the constraints of universality and of rapid convergence after reconfiguration must display a form of non-stationary behavior (of which oscillatory dynamics are an example). We also observe that the periodicity of the oscillatory behavior of the protocol, when present, must necessarily depend on the number ^\\# X of source agents present in the population. For instance, our protocols inherently rely on the emergence of a signal passing through the population, whose period is \Theta(\log \frac{n}{^\\# X}) rounds for most starting configurations. The design of clocks with tunable frequency may be of independent interest, notably in modeling biological networks

    Anthropologies of Unemployment: New Perspectives on Work and Its Absence

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    [Excerpt] Anthropologies of Unemployment offers accessible, theoretically innovative, and ethnographically rich examinations of unemployment in rural and urban regions across North and South America, Europe, Africa, and Asia. The diversity of case studies demonstrates that unemployment is a pressing global phenomenon that sheds light on the uneven consequences of free-market ideologies and policies. Economic, social, and cultural marginalization is common in the lives of the unemployed, but their experience and interpretation are shaped by local and national cultural particularities. In exploring those differences, the contributors to this volume employ recent theoretical innovations and engage with some of the more salient topics in contemporary anthropology, such as globalization, migration, youth cultures, bureaucracy, class, gender, and race. Taken together, the chapters reveal that there is something new about unemployment today. It is not a temporary occurrence, but a chronic condition. In adjusting to persistent, longstanding unemployment, people and groups create new understandings of unemployment as well as of work and employment; they improvise new forms of sociality, morality, and personhood. Ethnographic studies such as those found in Anthropologies of Unemployment are crucial if we are to understand the broader forms, meanings, and significance of pervasive economic insecurity and discover the emergence of new social and cultural possibilities

    An investigation into linearity with cumulative emissions of the climate and carbon cycle response in HadCM3LC

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    We investigate the extent to which global mean temperature, precipitation, and the carbon cycle are constrained by cumulative carbon emissions throughout four experiments with a fully coupled climate-carbon cycle model. The two paired experiments adopt contrasting, idealised approaches to climate change mitigation at different action points this century, with total emissions exceeding two trillion tonnes of carbon in the later pair. Their initially diverging cumulative emissions trajectories cross after several decades, before diverging again. We find that their global mean temperatures are, to first order, linear with cumulative emissions, though regional differences in temperature of up to 1.5K exist when cumulative emissions of each pair coincide. Interestingly, although the oceanic precipitation response scales with cumulative emissions, the global precipitation response does not, due to a decrease in precipitation over land above cumulative emissions of around one trillion tonnes of carbon (TtC). Most carbon fluxes and stores are less well constrained by cumulative emissions as they reach two trillion tonnes. The opposing mitigation approaches have different consequences for the Amazon rainforest, which affects the linearity with which the carbon cycle responds to cumulative emissions. Averaged over the two fixed-emissions experiments, the transient response to cumulative carbon emissions (TCRE) is 1.95 K TtC-1, at the upper end of the IPCC’s range of 0.8-2.5 K TtC-1

    Strong spectral evolution during the prompt emission of GRB 070616

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    Swift has revealed features in GRB early light curves, such as steep decays and X-ray flares, whose properties are consistent with an internal origin though they are far from understood. The steep X-ray decay is often explained using the curvature effect; however a significant number of GRBs display strong spectral evolution during this phase, and a new mechanism must be invoked to explain this. Of particular interest are the longest duration GRBs in which the early emission can be studied in most detail. Here we present data for GRB 070616, in which the prompt emission shows a complex multipeaked structure, leading to one of the longest prompt emission durations ever recorded. We take advantage of extensive coverage of such a long burst by all Swift instruments. Combining data from Swift and Suzaku we study the evolution of the prompt emission spectrum, following the temporal variability of the peak energy and spectral slope.Comment: 4 pages, 2 figures (Fig 1 in colour), contributed talk, submitted to the proceedings of Gamma Ray Bursts 2007, Santa Fe, New Mexico, November 5-9 200

    Towards a Model of Understanding Social Search

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    Search engine researchers typically depict search as the solitary activity of an individual searcher. In contrast, results from our critical-incident survey of 150 users on Amazon's Mechanical Turk service suggest that social interactions play an important role throughout the search process. Our main contribution is that we have integrated models from previous work in sensemaking and information seeking behavior to present a canonical social model of user activities before, during, and after search, suggesting where in the search process even implicitly shared information may be valuable to individual searchers.Comment: Presented at 1st Intl Workshop on Collaborative Information Seeking, 2008 (arXiv:0908.0583
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