384 research outputs found

    Predictive value of testing for multiple genetic variants in multifactorial

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    Multifactorial diseases such as type 2 diabetes, osteoporosis, and cardiovascular disease are caused by a complex interplay of many genetic and nongenetic factors, each of which conveys a minor increase in the risk of disease. Unraveling the genetic origins of these diseases is expected to lead to individualized medicine, in which the prevention and treatment strategies are personalized on the basis of the results of predictive genetic tests. This great optimism is counterbalanced by concerns about the ethical, legal, and social implications of genomic medicine, such as the protection of privacy and autonomy, stigmatization, discrimination, and the psychological burden of genetic testing. These concerns are translated from genetic testing in monogenic disorders, but this translation may not be appropriate. Multiple genetic testing (genomic profiling) has essential differences from genetic testing in monogenic disorders. The differences lie in the lower predictive value of the test results, the pleiotropic effects of susceptibility genes, and the low inheritance of genomic profiles. For these reasons, genomic profiling may be more similar to nongenetic tests than to predictive tests for monogenic diseases. Therefore, ethical, legal, and social issues that apply to predictive genetic testing for monogenic diseases may not be relevant for the prediction of multifactorial disorders in genomic medicine

    Rational and intuitive approaches to music composition: The impact of individual differences in thinking/learning styles on compositional processes

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    This study explores the idea that there are two different types of composers, those that use a rational process of composition involving pre-planning and use of external systems and those that use an intuitive process that involves trial and error or other exploratory means for composing. It focuses on further understanding these patterns of thought as they are found in the compositional processes of student composers as well as investigating their learning preferences. The study examines the compositional processes of five composition students from the Sydney Conservatorium of Music selected using their results on the SOLAT (Style Of Learning And Thinking) measure (Torrance, McCarthy & Kolesinski, 1988). After interviewing the five participants, a model was developed that explained how rational and intuitive patterns of thought were used at different levels. The macroprocesses of participants were found to sit on a continuum between rational and intuitive whilst at the micro-level participants were seen to use a mixture of both processes. The interview participants were also asked to comment on their preferred activities for learning composition. It was found that the participants believed their compositional processes were something that they developed themselves and they wanted a more personal approach to learning. The findings have implications for both teachers of composition and their students

    A serious game designed to explore and understand the complexities of flood mitigation options in Urban-Rural Catchments

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    Flood prevention in mixed urban-rural environments has become a greater concern due to climate change. It is a complex task requiring both efficient management of resources and the involvement of multiple stakeholders from diverse backgrounds. As Serious Games (games used for purposes other than mere entertainment) have emerged as an effective means of engaging stakeholders, this work proposes a new Serious Game applied to flood mitigation in the village of Millbrook in the UK. Results show that the game has both an informative and a transformative effect (statistical significance levels from 0.01 to 0.05), improving participants' understanding of the problem, and helping them to find a new and improved approach to flood risk management in Millbrook, with the potential to improve resilience significantly. Furthermore, the game successfully transformed participants into "citizen scientists" in the purest sense of the term-it led them to use inductive reasoning from data produced by the game to correctly confirm or reject hypotheses and resulted in more than 70% of the participants revising their initial assumptions. Interestingly, the game instigated the formation of new local partnerships and helped to prioritize the discussion of natural flood management measures in Millbrook Parish Council meetings

    Topological defects: A problem for cyclic universes?

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    We study the behaviour of cosmic string networks in contracting universes, and discuss some of their possible consequences. We note that there is a fundamental time asymmetry between defect network evolution for an expanding universe and a contracting universe. A string network with negligible loop production and small-scale structure will asymptotically behave during the collapse phase as a radiation fluid. In realistic networks these two effects are important, making this solution only approximate. We derive new scaling solutions describing this effect, and test them against high-resolution numerical simulations. A string network in a contracting universe, together with the gravitational radiation background it has generated, can significantly affect the dynamics of the universe both locally and globally. The network can be an important source of radiation, entropy and inhomogeneity. We discuss the possible implications of these findings for bouncing and cyclic cosmological models.Comment: 11 RevTeX 4 pages, 6 figures; version to appear in Phys. Rev.

    Aspects of String-Gas Cosmology at Finite Temperature

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    We study string-gas cosmology in dilaton gravity, inspired by the fact that it naturally arises in a string theory context. Our main interest is the thermodynamical treatment of the string-gas and the resulting implications for the cosmology. Within an adiabatic approximation, thermodynamical equilibrium and a small, toroidal universe as initial conditions, we numerically solve the corresponding equations of motions in two different regimes describing the string-gas thermodynamics: (i) the Hagedorn regime, with a single scale factor, and (ii) an almost-radiation dominated regime, which includes the leading corrections due to the lightest Kaluza Klein and winding modes, with two scale factors. The scale factor in the Hagedorn regime exhibits very slow time evolution with nearly constant energy and negligible pressure. By contrast, in case (ii) we find interesting cosmological solutions where the large dimensions continue to expand and the small ones are kept undetectably small.Comment: 21 pages, 5 eps figure

    Quotients of AdS_{p+1} x S^q: causally well-behaved spaces and black holes

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    Starting from the recent classification of quotients of Freund--Rubin backgrounds in string theory of the type AdS_{p+1} x S^q by one-parameter subgroups of isometries, we investigate the physical interpretation of the associated quotients by discrete cyclic subgroups. We establish which quotients have well-behaved causal structures, and of those containing closed timelike curves, which have interpretations as black holes. We explain the relation to previous investigations of quotients of asymptotically flat spacetimes and plane waves, of black holes in AdS and of Godel-type universes.Comment: 48 pages; v2: minor typos correcte

    Nonclassical statistics of intracavity coupled χ(2)\chi^{(2)} waveguides: the quantum optical dimer

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    A model is proposed where two χ(2)\chi^{(2)} nonlinear waveguides are contained in a cavity suited for second-harmonic generation. The evanescent wave coupling between the waveguides is considered as weak, and the interplay between this coupling and the nonlinear interaction within the waveguides gives rise to quantum violations of the classical limit. These violations are particularly strong when two instabilities are competing, where twin-beam behavior is found as almost complete noise suppression in the difference of the fundamental intensities. Moreover, close to bistable transitions perfect twin-beam correlations are seen in the sum of the fundamental intensities, and also the self-pulsing instability as well as the transition from symmetric to asymmetric states display nonclassical twin-beam correlations of both fundamental and second-harmonic intensities. The results are based on the full quantum Langevin equations derived from the Hamiltonian and including cavity damping effects. The intensity correlations of the output fields are calculated semi-analytically using a linearized version of the Langevin equations derived through the positive-P representation. Confirmation of the analytical results are obtained by numerical simulations of the nonlinear Langevin equations derived using the truncated Wigner representation.Comment: 15 pages, 8 figures, submitted to Phys. Rev.

    Increased upconversion performance for thin film solar cells a trimolecular composition

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    Photochemical upconversion based on triplet triplet annihilation TTA UC is employed to enhance the short circuit currents generated by two varieties of thin amp; 64257;lm solar cells, a hydrogenated amorphous silicon a Si H solar cell and a dye sensitized solar cell DSC . TTA UC is exploited to harvest transmitted sub bandgap photons, combine their energies and re radiate upconverted photons back towards the solar cells. In the present study we employ a dual emitter TTA UC system which allows for signi amp; 64257;cantly improved UC quantum yields as compared to the previously used single emitter TTA systems. In doing so we achieve record photo current enhancement values for both the a Si H device and the DSC, surpassing 10 3 mA cm 2 sun 2 for the amp; 64257;rst time for a TTA UC system and marking a record for upconversion enhanced solar cells in general. We discuss pertinent challenges of the TTA UC technology which need to be addressed in order to achieve its viable device application

    A randomized controlled trial of home visits by neighborhood mentor mothers to improve children's nutrition in South Africa

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    Malnourished children and babies with birth weights under 2500 g are at high risk for negative outcomes over their lifespans. Philani, a paraprofessional home visiting program, was developed to improve nutritional outcomes for young children in South Africa. One “mentor mother” was recruited from each of 37 neighborhoods in Cape Town, South Africa. Mentor mothers were trained to conduct home visits to weigh children under six years old and to support mothers to problem-solve life challenges, especially around nutrition. Households with underweight children were assigned randomly on a 2:1 ratio to the Philani program (n = 500) or to a standard care condition (n = 179); selection effects occurred and children in the intervention households weighed less at recruitment. Children were evaluated over a one-year period (n = 679 at recruitment and n = 638 with at least one follow-up; 94%). Longitudinal random effects models indicated that, over 12 months, the children in the intervention condition gained significantly more weight than children in the control condition. Mentor mothers who are positive peer deviants may be a viable strategy that is efficacious and can build community, and the use of mentor mothers for other problems in South Africa is discussed
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