2,321 research outputs found

    J.S. Bell's Concept of Local Causality

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    John Stewart Bell's famous 1964 theorem is widely regarded as one of the most important developments in the foundations of physics. It has even been described as "the most profound discovery of science." Yet even as we approach the 50th anniversary of Bell's discovery, its meaning and implications remain controversial. Many textbooks and commentators report that Bell's theorem refutes the possibility (suggested especially by Einstein, Podolsky, and Rosen in 1935) of supplementing ordinary quantum theory with additional ("hidden") variables that might restore determinism and/or some notion of an observer-independent reality. On this view, Bell's theorem supports the orthodox Copenhagen interpretation. Bell's own view of his theorem, however, was quite different. He instead took the theorem as establishing an "essential conflict" between the now well-tested empirical predictions of quantum theory and relativistic \emph{local causality}. The goal of the present paper is, in general, to make Bell's own views more widely known and, in particular, to explain in detail Bell's little-known mathematical formulation of the concept of relativistic local causality on which his theorem rests. We thus collect and organize many of Bell's crucial statements on these topics, which are scattered throughout his writings, into a self-contained, pedagogical discussion including elaborations of the concepts "beable", "completeness", and "causality" which figure in the formulation. We also show how local causality (as formulated by Bell) can be used to derive an empirically testable Bell-type inequality, and how it can be used to recapitulate the EPR argument.Comment: 19 pages, 4 figure

    Glovebox for GeoLab Subsystem in HDU1-PEM

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    The GeoLab glovebox was designed to enable the preliminary examination, by astronauts, of geological samples collected from the surface of another planetary body. The collected information would then aid scientists in making decisions about sample curation and prioritization for return to Earth for study. This innovation was designed around a positive- pressure-enriched nitrogen environment glovebox to reduce sample handling contamination. The structure was custom-designed to fit in section H of NASA s Habitat Demonstration Unit 1 Pressurized Excursion Module (HDU1- PEM). In addition, the glovebox was designed to host analytical instruments in a way that prevents sample contamination

    A Family Day program enhances knowledge about medical school culture and necessary supports

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    BACKGROUND: A Family Day program was implemented at Indiana University School of Medicine to educate the families and friends of in-coming medical students about the rigors of medical school and the factors that contribute to stress. METHODS: Surveys that assessed knowledge, beliefs, and attitudes about medical school were administered to participants before and after the program. RESULTS: After the program, participants showed a significant improvement in their understanding of medical school culture and the importance of support systems for medical students. Post-test scores improved by an average of 29% (P < 0.001) in each of the two years this program was administered. CONCLUSIONS: The inclusion of family members and other loved ones in pre-matriculation educational programs may serve to mitigate the stress associated with medical school by enhancing the students' social support systems

    Divining integrative medicine

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    Phylogenetic Signal, Root Morphology, Mycorrhizal Type, and Macroinvertebrate Exclusion: Exploring Wood Decomposition in Soils Conditioned by 13 Temperate Tree Species

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    Woodlands are pivotal to carbon stocks, but the process of cycling C is slow and may be most effective in the biodiverse root zone. How the root zone impacts plants has been widely examined over the past few decades, but the role of the root zone in decomposition is understudied. Here, we examined how mycorrhizal association and macroinvertebrate activity influences wood decomposition across diverse tree species. Within the root zone of six predominantly arbuscular mycorrhizal (AM) (Acer negundo, Acer saccharum, Prunus serotina, Juglans nigra, Sassafras albidum, and Liriodendron tulipfera) and seven predominantly ectomycorrhizal (EM) tree species (Carya glabra, Quercus alba, Quercus rubra, Betula alleghaniensis, Picea rubens, Pinus virginiana, and Pinus strobus), woody litter was buried for 13 months. Macroinvertebrate access to woody substrate was either prevented or not using 0.22 mm mesh in a common garden site in central Pennsylvania. Decomposition was assessed as proportionate mass loss, as explained by root diameter, phylogenetic signal, mycorrhizal type, canopy tree trait, or macroinvertebrate exclusion. Macroinvertebrate exclusion significantly increased wood decomposition by 5.9%, while mycorrhizal type did not affect wood decomposition, nor did canopy traits (i.e., broad leaves versus pine needles). Interestingly, there was a phylogenetic signal for wood decomposition. Local indicators for phylogenetic associations (LIPA) determined high values of sensitivity value in Pinus and Picea genera, while Carya, Juglans, Betula, and Prunus yielded low values of sensitivity. Phylogenetic signals went undetected for tree root morphology. Despite this, roots greater than 0.35 mm significantly increased woody litter decomposition by 8%. In conclusion, the findings of this study suggest trees with larger root diameters can accelerate C cycling, as can trees associated with certain phylogenetic clades. In addition, root zone macroinvertebrates can potentially limit woody C cycling, while mycorrhizal type does not play a significant role

    Biology and population studies of two endemic Nematoceras (orchid) species on sub-Antarctic Macquarie Island

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    Two endemic orchid species, Nematoceras dienemum and N. sulcatum, are known from sub-Antarctic Macquarie Island. Several additional orchid populations on the island are reported and deistogamy is documented in N. dienemum for the first time. The known population sizes, habitats and locations for both orchid species are documented here, and new information on their biology and population ecology is provided

    Condoms and developmental contexts in younger adolescent boys

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    BACKGROUND: Condom use is a key part of sexually transmitted infection (STI) prevention for young men. Yet little is known about how younger adolescent boys initially learn about and use condoms. We examined sources of information, attitudes towards, acquisition, practice and early use of condoms among 14-16-year-old boys. METHODS: Thirty 14-16-year-old boys were recruited from a teen clinic serving a community with high STI rates and were asked open-ended questions about condoms, such as, "Where did you learn about condoms?" and "In what situations would you/would you not, use condoms." Interviews were audio recorded, transcribed and coded. Qualitative analysis focused upon key concepts and shared social cognitions related to condom use. RESULTS: Both sexually inexperienced and experienced participants perceived that sex feels or would feel less pleasurable with condoms. For almost all participants, families were the primary source of both information about condoms and of condoms themselves. This information focused on pregnancy prevention, with STIs secondary. Participants' views of condoms fell into three developmental groups: not interested in condoms and equating their use with interest in sex; exploring condoms out of either curiosity or in preparation for sex; and experienced with condom use. Exploring included behaviours such as checking condoms out and trying them on. CONCLUSIONS: Our findings of existing negative perceptions of condoms, the importance of families in learning about condoms and the developmental need to test and try on condoms before use have implications for adolescent STI prevention programmes

    Collaborative Inter-relational Healthcare Research: A Conceptual Framework Informed by a Qualitative Enquiry

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    Background: Interprofessional education is an important precursor to developing collaborative interprofessional healthcare teams. Both have been studied extensively. Less is known about factors contributing to successful interprofessional research. This study examined the perspectives of members of an interprofessional healthcare research team regarding their involvement as research team members.Methods & Findings: Phase 1: Semi-structured one-on-one interviews were conducted with research team members. Interviews were audiotaped and transcribed verbatim. Each transcript was analyzed using a comparative contrast approach. Concepts emerging from the data were categorized broadly under the following themes: raison d’être, key elements of an interprofessional research team, communication, unavoidable logistics, and what is the value? Phase 2: Upon completion of the analysis, a preliminary conceptual framework for conducting interprofessional healthcare research was proposed and presented to the research team. Phase 3: A validation process was undertaken to further define the framework.Conclusions: Key components of the conceptual framework included values (trust, respect for each other, and common interest[s]) and structural prerequisites (expertise in the topic area, funding, team leadership time, associated workload, organized and co-ordinated management, and forums for multi-modal communication)
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