7,771 research outputs found
Modeling interdisciplinary activities involving mathematics and philosophy
In this paper a didactical model is presented. The goal of the model is to work as a didactical tool, or conceptual frame, for developing, carrying through and evaluating interdisciplinary activities involving the subject of mathematics and philosophy in the high schools. Through the terms of Horizontal Intertwining, Vertical Structuring and Horizontal Propagation the model consists of three phases, each considering different aspects of the nature of interdisciplinary activities. The theoretical modelling is inspired by work which focuses on the students abilities to concept formation in expanded domains (Michelsen, 2001, 2005a, 2005b). Furthermore the theoretical description rest on a series of qualitative interviews with teachers from the Danish high school (grades 9-11) conducted recently. The special case of concrete interdisciplinary activities between mathematics and philosophy is also considered
High temperature thermoelectric efficiency in Ba8Ga16Ge30
The high thermoelectric figure of merit (zT) of Ba8Ga16Ge30 makes it one of the best n-type materials for thermoelectric power generation. Here, we describe the synthesis and characterization of a Czochralski pulled single crystal of Ba8Ga16Ge30 and polycrystalline disks. Measurements of the electrical conductivity, Hall effect, specific heat, coefficient of thermal expansion, thermal conductivity, and Seebeck coefficient were performed up to 1173 K and compared with literature results. Dilatometry measurements give a coefficient of thermal expansion of 16×10^−6 K^−1 up to 1175 K. The trend in electronic properties with composition is typical of a heavily doped semiconductor. The maximum in the thermoelectric figure of merit is found at 1050 K with a value of 0.8. The correction of zT due to thermal expansion is not significant compared to the measurement uncertainties involved. Comparing the thermoelectric efficiency of segmented materials, the effect of compatibility makes Ba8Ga16Ge30 more efficient than the higher zT n-type materials SiGe or skutterudite CoSb3
The politics of opting out: explaining educational financing and popular support for public spending
In this paper, we address two empirical puzzles: Why are cross-country differences in the division of labour between public and private education funding so large and why are they politically sustainable in the long term? We argue that electoral institutions play a crucial role in shaping politico-economic distributive coalitions that affected the original division of labour in education financing. In proportional representation systems, the lower and middle classes formed a coalition supporting the establishment of a system with a large share of public funding. In majoritarian systems, in contrast, the middle class voters aligned with the upper income class and supported private education spending instead. Once established, institutional arrangements create feedback effects on the micro-level of attitudes, reinforcing political support even among upper middle classes in public systems. These hypotheses are tested empirically both on the micro level of preferences as well as on the macro level with aggregate data and survey data from the ISSP for 20 Organization for Economic Co-operation and Development countries.Governmen
Unchanged thermopower enhancement at the semiconductor-metal transition in correlated FeSbTe
Substitution of Sb in FeSb by less than 0.5% of Te induces a transition
from a correlated semiconductor to an unconventional metal with large effective
charge carrier mass . Spanning the entire range of the semiconductor-metal
crossover, we observed an almost constant enhancement of the measured
thermopower compared to that estimated by the classical theory of electron
diffusion. Using the latter for a quantitative description one has to employ an
enhancement factor of 10-30. Our observations point to the importance of
electron-electron correlations in the thermal transport of FeSb, and
suggest a route to design thermoelectric materials for cryogenic applications.Comment: 3 pages, 3 figures, accepted for publication in Appl. Phys. Lett.
(2011
Experimental investigation of vortices shed by various wing fin configurations
Forty-six different fins, which were members of twelve plan-form families, were tested. A two dimensional Boeing single element airfoil at an angle of attack of eight degrees and a sweepback angle of thirty-two was used to simulate a portion of the wing of a generator aircraft. Various free stream velocities were used to test any individual fin at its particular angle of attack. While the fin itself was mounted on the upper surface of the generator model, the angle of attack of each fin was varied until stall was reached and/or passed. The relative fin vortex strengths were measured in two ways. First, the maximum angular velocity of a four blade rotor placed in the fin vortex center was measured with the use of a stroboscope. Second, the maximum rolling moment on a following wing model placed in the fin vortex center was measured by a force balance
How 25 years of psychosocial research has contributed to a better understanding of the links between depression and diabetes
This narrative review of the literature provides a summary and discussion of 25 years of research into the complex links between depression and diabetes. Systematic reviews have shown that depression occurs more frequently in people with type 1 or type 2 diabetes compared with people without diabetes. Currently, it remains unclear whether depression is also more common in people with impaired glucose metabolism or undiagnosed type 2 diabetes compared with people without diabetes. More prospective epidemiological research into the course of depression and an exploration of mechanisms in individuals with diabetes are needed.Depression in diabetes is associated with less optimal self-care behaviours, suboptimal glycaemic control, impaired quality of life, incident micro- and macrovascular diseases, and elevated mortality rates. Randomized controlled trails concluded that depression in diabetes can be treated with antidepressant medication, cognitive–behavioural therapy (individual, group-based or web-based), mindfulness-based cognitive therapy and stepped care. Although big strides forward have been made in the past 25 years, scientific evidence about depression in diabetes remains incomplete. Future studies should investigate mechanisms that link both conditions and test new diabetes-specific web- or app-based interventions for depression in diabetes. It is important to determine whether treatment or prevention of depression prevents future diabetes complications and lowers mortality rates
The Partisan Politics of New Social Risks in Advanced Postindustrial Democracies: Social Protection for Labor Market Outsiders
Advanced postindustrialization generates numerous challenges for the European social model. Central among these challenges is declining income, unstable employment, and inadequate training of semi- and unskilled workers. In this chapter, I assess the partisan basis of support for social policies that address the needs of these marginalized workers. I specifically consider the impacts of postindustrial cleavages among core constituencies of social democratic parties on the capacity of these parties to pursue inclusive social policies. I argue – and find support for in empirical analyses – that encompassing labor organization is the most important factor in strengthening the ability of left parties to build successful coalitions in support of outsider-friendly policies. I go beyond existing work on the topic by considering the full array of postindustrial cleavages facing left parties, by more fully elaborating why encompassing labor organization is crucial, and by considering a more complete set of measures of outsider policies than extant work. I compare my arguments and findings to important new work that stresses coalition building and partisan politics but minimizes the role of class organization
Bayesian model search and multilevel inference for SNP association studies
Technological advances in genotyping have given rise to hypothesis-based
association studies of increasing scope. As a result, the scientific hypotheses
addressed by these studies have become more complex and more difficult to
address using existing analytic methodologies. Obstacles to analysis include
inference in the face of multiple comparisons, complications arising from
correlations among the SNPs (single nucleotide polymorphisms), choice of their
genetic parametrization and missing data. In this paper we present an efficient
Bayesian model search strategy that searches over the space of genetic markers
and their genetic parametrization. The resulting method for Multilevel
Inference of SNP Associations, MISA, allows computation of multilevel posterior
probabilities and Bayes factors at the global, gene and SNP level, with the
prior distribution on SNP inclusion in the model providing an intrinsic
multiplicity correction. We use simulated data sets to characterize MISA's
statistical power, and show that MISA has higher power to detect association
than standard procedures. Using data from the North Carolina Ovarian Cancer
Study (NCOCS), MISA identifies variants that were not identified by standard
methods and have been externally ``validated'' in independent studies. We
examine sensitivity of the NCOCS results to prior choice and method for
imputing missing data. MISA is available in an R package on CRAN.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS322 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
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