384 research outputs found
Predictive value of testing for multiple genetic variants in multifactorial
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
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
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?
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
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
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 waveguides: the quantum optical dimer
A model is proposed where two 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
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
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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