1,139 research outputs found

    Super-stability in the Student-Project Allocation Problem with Ties

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    The Student-Project Allocation problem with lecturer preferences over Students ( Open image in new window ) involves assigning students to projects based on student preferences over projects, lecturer preferences over students, and the maximum number of students that each project and lecturer can accommodate. This classical model assumes that preference lists are strictly ordered. Here, we study a generalisation of Open image in new window where ties are allowed in the preference lists of students and lecturers, which we refer to as the Student-Project Allocation problem with lecturer preferences over Students with Ties ( Open image in new window ). We investigate stable matchings under the most robust definition of stability in this context, namely super-stability. We describe the first polynomial-time algorithm to find a super-stable matching or to report that no such matching exists, given an instance of Open image in new window . Our algorithm runs in O(L) time, where L is the total length of all the preference lists. Finally, we present results obtained from an empirical evaluation of the linear-time algorithm based on randomly-generated Open image in new window instances. Our main finding is that, whilst super-stable matchings can be elusive, the probability of such a matching existing is significantly higher if ties are restricted to the lecturers’ preference lists

    Human genetics in troubled times and places

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    Abstract The development of human genetics world-wide during the twentieth century, especially across Europe, has occurred against a background of repeated catastrophes, including two world wars and the ideological problems and repression posed by Nazism and Communism. The published scientific literature gives few hints of these problems and there is a danger that they will be forgotten. The First World War was largely indiscriminate in its carnage, but World War 2 and the preceding years of fascism were associated with widespread migration, especially of Jewish workers expelled from Germany, and of their children, a number of whom would become major contributors to the post-war generation of human and medical geneticists in Britain and America. In Germany itself, eminent geneticists were also involved in the abuses carried out in the name of ‘eugenics’ and ‘race biology’. However, geneticists in America, Britain and the rest of Europe were largely responsible for the ideological foundations of these abuses. In the Soviet Union, geneticists and genetics itself became the object of persecution from the 1930s till as late as the mid 1960s, with an almost complete destruction of the field during this time; this extended also to Eastern Europe and China as part of the influence of Russian communism. Most recently, at the end of the twentieth century, China saw a renewal of government sponsored eugenics programmes, now mostly discarded. During the post-world war 2 decades, human genetics research benefited greatly from recognition of the genetic dangers posed by exposure to radiation, following the atomic bomb explosions in Japan, atmospheric testing and successive accidental nuclear disasters in Russia. Documenting and remembering these traumatic events, now largely forgotten among younger workers, is essential if we are to fully understand the history of human genetics and avoid the repetition of similar disasters in the future. The power of modern human genetic and genomic techniques now gives a greater potential for abuse as well as for beneficial use than has ever been seen in the past

    A qualitative study of independent fast food vendors near secondary schools in disadvantaged Scottish neighbourhoods

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    Background: Preventing and reducing childhood and adolescent obesity is a growing priority in many countries. Recent UK data suggest that children in more deprived areas have higher rates of obesity and poorer diet quality than those in less deprived areas. As adolescents spend a large proportion of time in school, interventions to improve the food environment in and around schools are being considered. Nutrient standards for school meals are mandatory in the UK, but many secondary pupils purchase foods outside schools at break or lunchtime that may not meet these standards. Methods: Qualitative interviews were conducted with fast food shop managers to explore barriers to offering healthier menu options. Recruitment targeted independently-owned shops near secondary schools (pupils aged c.12-17) in low-income areas of three Scottish cities. Ten interviews were completed, recorded, and transcribed for analysis. An inductive qualitative approach was used to analyse the data in NVivo 10. Results: Five themes emerged from the data: pride in what is sold; individual autonomy and responsibility; customer demand; profit margin; and neighbourhood context. Interviewees consistently expressed pride in the foods they sold, most of which were homemade. They felt that healthy eating and general wellbeing are the responsibility of the individual and that offering what customers want to eat, not necessarily what they should eat, was the only way to stay in business. Most vendors felt they were struggling to maintain a profit, and that many aspects of the low-income neighbourhood context would make change difficult or impossible. Conclusions: Independent food shops in low-income areas face barriers to offering healthy food choices, and interventions and policies that target the food environment around schools should take the neighbourhood context into consideration

    P2P Web service based system for supporting decision-making in cellular manufacturing scheduling

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    With the increase of the Internet and Virtual Enterprises (VEs), interfaces for web systems and automated services are becoming an emergent necessity. In this paper we propose a Peer-to-peer (P2P) web-based decision-support system for enabling access to different manufacturing scheduling methods, which can be remotely available and accessible from a distributed knowledge base. The XML-based modeling and communication is applied to manufacturing scheduling. Therefore, manufacturing scheduling problems and methods are modeled using XML. The proposed P2P web-based system works as web services, under the SOAP protocol. The system’s distributed knowledge base enables sharing information about scheduling problems and corresponding solving methods in a widened search space, through a scheduling community, integrating a VE. Running several methods enables different results for a given problem, consequently, contributing for a better decision-making. An important aspect is that this knowledge base can be easily and continuously updated by any contributor through the VE. Moreover, through this system once suitable available methods, for a given problem, are identified, it enables running one or more of them, for enabling a better manufacturing scheduling support, enhanced though incorporated fuzzy decision-making proceduresAichi Science and Technology Foundation(PTDC/EME-GIN/102143/2008)info:eu-repo/semantics/publishedVersio

    The Economic Archaeology of Roman Economic Performance

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    Recent years have witnessed a paradigm shift in the study of the Roman economy. Methodologically modern economic analysis is now far more acceptable than it once was, and archaeology has become the major source of empirical data for many questions. On the substantive side there is now a far clearer appreciation of the major changes that the Roman economy underwent, with substantial growth of population and aggregate production and even some improvements in standard of living, but followed by equally dramatic decline. This economic success was not limited to the imperial core, but also extended to the provinces

    Veratridine produces distinct calcium response profiles in mouse Dorsal Root Ganglia neurons.

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    Nociceptors are a subpopulation of dorsal root ganglia (DRG) neurons that detect noxious stimuli and signal pain. Veratridine (VTD) is a voltage-gated sodium channel (VGSC) modifier that is used as an "agonist" in functional screens for VGSC blockers. However, there is very little information on VTD response profiles in DRG neurons and how they relate to neuronal subtypes. Here we characterised VTD-induced calcium responses in cultured mouse DRG neurons. Our data shows that the heterogeneity of VTD responses reflects distinct subpopulations of sensory neurons. About 70% of DRG neurons respond to 30-100 μM VTD. We classified VTD responses into four profiles based upon their response shape. VTD response profiles differed in their frequency of occurrence and correlated with neuronal size. Furthermore, VTD response profiles correlated with responses to the algesic markers capsaicin, AITC and α, β-methylene ATP. Since VTD response profiles integrate the action of several classes of ion channels and exchangers, they could act as functional "reporters" for the constellation of ion channels/exchangers expressed in each sensory neuron. Therefore our findings are relevant to studies and screens using VTD to activate DRG neurons
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