1,651 research outputs found

    In Defense of Dynamical Explanation

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    Proponents of mechanistic explanation have argued that dynamical models are mere phenomenal models, in that they describe rather than explain the scientific phenomena produced by complex systems. I argue instead that dynamical models can, in fact, be explanatory. Using an example from neuroscientific research on epilepsy, I show that dynamical models can meet the explanatory demands met by mechanistic models, and as such occupy their own unique place within the space of explanatory scientific models

    Global Action on Social Determinants of Health: National Approaches to Addressing Health Disparities

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    Strategies to address health disparities, including through a social determinants approach, vary according to stakeholders\u27principles, defined priorities, partners, evidence base, and understanding of pathways, not to mention political and economic factors. This presentation will look at the experiences of the Global Equity Gauge Alliance and the World Health Organization Commission on Social Determinants of Health in supporting local and national initiatives in Latin America, Africa and Asia to reduce disparities. The presentation will describe the frameworks proposed by GEGA and the WHO CSDH, present the initiatives adopted by several countries, explain how strategies were adapted to fit local and national priorities and conditions, and look at some of the common lessons learned

    Infrared Evidence for Collagen Structures

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71134/2/JCPSA6-22-9-1621-1.pd

    A Variational Principle Based Study of KPP Minimal Front Speeds in Random Shears

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    Variational principle for Kolmogorov-Petrovsky-Piskunov (KPP) minimal front speeds provides an efficient tool for statistical speed analysis, as well as a fast and accurate method for speed computation. A variational principle based analysis is carried out on the ensemble of KPP speeds through spatially stationary random shear flows inside infinite channel domains. In the regime of small root mean square (rms) shear amplitude, the enhancement of the ensemble averaged KPP front speeds is proved to obey the quadratic law under certain shear moment conditions. Similarly, in the large rms amplitude regime, the enhancement follows the linear law. In particular, both laws hold for the Ornstein-Uhlenbeck process in case of two dimensional channels. An asymptotic ensemble averaged speed formula is derived in the small rms regime and is explicit in case of the Ornstein-Uhlenbeck process of the shear. Variational principle based computation agrees with these analytical findings, and allows further study on the speed enhancement distributions as well as the dependence of enhancement on the shear covariance. Direct simulations in the small rms regime suggest quadratic speed enhancement law for non-KPP nonlinearities.Comment: 28 pages, 14 figures update: fixed typos, refined estimates in section

    Isospin splitting of the nucleon mean field

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    The isospin splitting of the nucleon mean field is derived from the Brueckner theory extended to asymmetric nuclear matter. The Argonne V18 has been adopted as bare interaction in combination with a microscopic three body force. The isospin splitting of the effective mass is determined from the Brueckner-Hartree-Fock self-energy: It is linear acording to the Lane ansatz and such that mn>mpm^*_n > m^*_p for neutron-rich matter. The symmetry potential is also determined and a comparison is made with the predictions of the Dirac-Brueckner approach and the phenomenological interactions. The theoretical predictions are also compared with the empirical parametrizations of neutron and proton optical-model potentials based on the experimental nucleon-nucleus scattering and the phenomenological ones adopted in transport-model simulations of heavy-ion collisions. The direct contribution of the rearrangement term due to three-body forces to the single particle potential and symmetry potential is discussed.Comment: 8 pages, 10 figure

    Slowdown for time inhomogeneous branching Brownian motion

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    We consider the maximal displacement of one dimensional branching Brownian motion with (macroscopically) time varying profiles. For monotone decreasing variances, we show that the correction from linear displacement is not logarithmic but rather proportional to T1/3T^{1/3}. We conjecture that this is the worse case correction possible

    Integrating Low- and High-Level Skills in Instructional Protocols for Writing Disabilities

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    Twenty-four children with writing problems were given instruction in handwriting automaticity, spelling strategies, and the composing process (plan, write, review, revise) in 14 one-hour individual tutorials during the summer between third and fourth grade. Half the children (8 boys, 4 girls) received extra practice in composing, while half the children (8 boys, 4 girls) received special training in orthographic and phonological coding. Hierarchical linear modeling of growth curves was used to compare the treatment groups to a non-contact control group (10 boys, 5 girls) on a standard battery at pretest, midtest, posttest, and the two treatment groups with each other on probe measures of handwriting, spelling, and composition in each tutorial session. The treatment groups improved at a faster rate than the control group on some measures of handwriting, spelling, and composition (fluency and quality) in the standard battery, but Verbal IQ did not predict rate of improvement. Differences were found between the two treatment groups in some probe measures of writing and a motivation variable (work avoidance). Repeated-measures ANOVA was used to compare treatment groups to a non-contact control group at pretest, midtest, posttest, and follow-up. Differences between the treatment and control groups favoring the treatment groups were maintained at 6- month follow-up on some handwriting, spelling, and composition (quality) measures. Individual differences were found in learner characteristics prior to treatment and in response to the same treatment. The importance of affect and motivation as well as cognitive variables is emphasized

    The influence of rumination and distraction on depressed and anxious mood: a prospective examination of the response styles theory in children and adolescents

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    The present study sought to test predictions of the response styles theory in a sample of children and adolescents. More specifically, a ratio approach to response styles was utilized to examine the effects on residual change scores in depression and anxiety. Participants completed a battery of questionnaires including measures of rumination, distraction, depression, and anxiety at baseline (Time 1) and 8–10 weeks follow-up (Time 2). Results showed that the ratio score of rumination and distraction was significantly associated with depressed and anxious symptoms over time. More specifically, individuals who have a greater tendency to ruminate compared to distracting themselves have increases in depression and anxiety scores over time, whereas those who have a greater tendency to engage in distraction compared to rumination have decreases in depression and anxiety symptoms over time. These findings indicate that a ratio approach can be used to examine the relation between response styles and symptoms of depression and anxiety in non-clinical children and adolescents. Implications of the results may be that engaging in distractive activities should be promoted and that ruminative thinking should be targeted in juvenile depression treatment

    Coulomb Energy of Nuclei

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    The density functional determining the Coulomb energy of nuclei is calculated to the first order in e2e^2. It is shown that the Coulomb energy includes three terms: the Hartree energy; the Fock energy; and the correlation Coulomb energy (CCE), which contributes considerably to the surface energy, the mass difference between mirror nuclei, and the single-particle spectrum. A CCE-based mechanism of a systematic shift of the single-particle spectrum is proposed. A dominant contribution to the CCE is shown to come from the surface region of nuclei. The CCE effect on the calculated proton drip line is examined, and the maximum charge ZZ of nuclei near this line is found to decrease by 2 or 3 units. The effect of Coulomb interaction on the effective proton mass is analyzed.Comment: 10 pages, Latex. Devoted to 90-th Anniversary of A.B. Migdal's Birthda

    An International Society and Journal for Equity in Health: 10 years on

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Commentary June 2010 marked the 10th Anniversary of the foundation meeting of the International Society for Equity in Health (ISEqH). The formation of the Society was a bold statement, with ambitions to be a global body "to promote equity in health and health services internationally through education, research, publication, communication and charitable support"[1]. The Society particularly aimed to be an organisation that facilitated research on how better to understand and address inequities in health. The main activities of the Society have been a series of biannual conferences as well as the establishment of the International Journal for Equity in Health, the official (but independent) publication of the Society. This paper sets out to record some of the milestones of the Society drawing on the reflections of key researchers who attended the conferences as well as others. The history of the Society will help shape its future and how it responds to important issues facing all interested in global efforts to address continuing and unacceptable inequities in health
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