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Substantial Gains (substantial + gain)
Selected AbstractsSubstantial Gains in Bias Reduction from Matching with a Variable Number of ControlsBIOMETRICS, Issue 1 2000Kewei Ming Summary. In observational studies that match several controls to each treated subject, substantially greater bias reduction is possible if the number of controls is not fixed but rather is allowed to vary from one matched set to another. In certain cases, matching with a fixed number of controls may remove only 50% of the bias in a covariate, whereas matching with a variable number of controls may remove 90% of the bias, even though both control groups have the same number of controls in total. An example of matching in a study of surgical mortality is discussed in detail. [source] Integrating pharmacology topics in high school biology and chemistry classes improves performanceJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 9 2003Rochelle D. Schwartz-Bloom Although numerous programs have been developed for Grade Kindergarten through 12 science education, evaluation has been difficult owing to the inherent problems conducting controlled experiments in the typical classroom. Using a rigorous experimental design, we developed and tested a novel program containing a series of pharmacology modules (e.g., drug abuse) to help high school students learn basic principles in biology and chemistry. High school biology and chemistry teachers were recruited for the study and they attended a 1-week workshop to learn how to integrate pharmacology into their teaching. Working with university pharmacology faculty, they also developed classroom activities. The following year, teachers field-tested the pharmacology modules in their classrooms. Students in classrooms using the pharmacology topics scored significantly higher on a multiple choice test of basic biology and chemistry concepts compared with controls. Very large effect sizes (up to 1.27 standard deviations) were obtained when teachers used as many as four modules. In addition, biology students increased performance on chemistry questions and chemistry students increased performance on biology questions. Substantial gains in achievement may be made when high school students are taught science using topics that are interesting and relevant to their own lives. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 922,938, 2003 [source] Keeping up or Falling behind?FISCAL STUDIES, Issue 4 2008Poverty, Tax Uprating on Incomes, The Impact of Benefit D31; I38 Abstract Each year, the government decides how much to raise benefits and tax allowances. In the UK, the basis for these upratings is rarely debated, yet has major long-term consequences for the relative living standards of different groups as well as for the public finances. This paper considers the medium-term implications of present uprating policies, which vary across parameters of the tax,benefit system. Continuing these policies for 20 years, other things staying the same, would result in a near doubling of the child poverty rate alongside a substantial gain to the public finances. At the same time, pensioners are largely protected by the earnings indexation of pensioner benefits including, in time, the basic state pension. We show how difficult it will be to meet the UK child poverty targets unless the greater inequality inherent in the current regime for uprating payments and allowances is redressed. [source] Incorporating covariates in mapping heterogeneous traits: a hierarchical model using empirical Bayes estimationGENETIC EPIDEMIOLOGY, Issue 7 2007Swati Biswas Abstract Complex genetic traits are inherently heterogeneous, i.e., they may be caused by different genes, or non-genetic factors, in different individuals. So, for mapping genes responsible for these diseases using linkage analysis, heterogeneity must be accounted for in the model. Heterogeneity across different families can be modeled using a mixture distribution by letting each family have its own heterogeneity parameter denoting the probability that its disease-causing gene is linked to the marker map under consideration. A substantial gain in power is expected if covariates that can discriminate between the families of linked and unlinked types are incorporated in this modeling framework. To this end, we propose a hierarchical Bayesian model, in which the families are grouped according to various (categorized) levels of covariate(s). The heterogeneity parameters of families within each group are assigned a common prior, whose parameters are further assigned hyper-priors. The hyper-parameters are obtained by utilizing the empirical Bayes estimates. We also address related issues such as evaluating whether the covariate(s) under consideration are informative and grouping of families. We compare the proposed approach with one that does not utilize covariates and show that our approach leads to considerable gains in power to detect linkage and in precision of interval estimates through various simulation scenarios. An application to the asthma datasets of Genetic Analysis Workshop 12 also illustrates this gain in a real data analysis. Additionally, we compare the performances of microsatellite markers and single nucleotide polymorphisms for our approach and find that the latter clearly outperforms the former. Genet. Epidemiol. 2007. © 2007 Wiley-Liss, Inc. [source] Computational economy improvements in PRISMINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 9 2003Shaheen R. Tonse The Piecewise Reusable Implementation of Solution Mapping (PRISM) procedure is applied to reactive flow simulations of (9-species) H2 + air combustion. PRISM takes the solution of the chemical kinetic ordinary differential equation system and parameterizes it with quadratic polynomials. To increase the accuracy, the parameterization is done piecewise, by dividing the multidimensional chemical composition space into hypercubes and constructing polynomials for each hypercube on demand. The polynomial coefficients are stored for subsequent repeated reuse. Initial cost of polynomial construction is expensive, but it recouped as the hypercube is reused, hence computational gain depends on the degree of hypercube reuse. We present two methods that help us to identify hypercubes that will ultimately have high reuse, this being accomplished before the expense of constructing polynomials has been incurred. One method utilizes the rate of movement of the chemical trajectory to estimate the number of steps the trajectory would make through the hypercube. The other method defers polynomial construction until a preset threshold of reuse has been met; an empirical method which, nevertheless, produces a substantial gain. The methods are tested on a 0-D chemical mixture and reactive flow 1-D and 2-D simulations of selected laminar and turbulent H2 + air flames. The computational performance of PRISM is improved by a factor of about 2 for both methods. © 2003 Wiley Periodicals, Inc., Int J Chem Kinet 35: 438,452, 2003 [source] Combining a polarizable force-field and a coarse-grained polarizable solvent model: Application to long dynamics simulations of bovine pancreatic trypsin inhibitorJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 11 2008Michel Masella Abstract The dynamic coupling between a polarizable protein force field and a particle-based implicit solvent model is described. The polarizable force field, TCPEp, developed recently to simulate protein systems, is characterized by a reduced number of polarizable sites, with a substantial gain in efficiency for an equal chemical accuracy. The Polarizable Pseudo-Particle (PPP) solvent model represents the macroscopic solvent polarization by induced dipoles placed on mobile Lennard-Jones pseudo-particles. The solvent-induced dipoles are sensitive to the solute electric field, but not to each other, so that the computational cost of solvent,solvent interactions is basically negligible. The solute and solvent induced dipoles are determined self-consistently and the equations of motion are solved using an efficient iterative multiple time step procedure. The solvation cost with respect to vacuum simulations is shown to decrease with solute size: the estimated multiplicative factor is 2.5 for a protein containing about 1000 atoms, and as low as 1.15 for 8000 atoms. The model is tested for six 20 ns molecular dynamics trajectories of a traditional benchmark system: the hydrated Bovine Pancreatic Trypsin Inhibitor (BPTI). Even though the TCPEp parameters have not been refined to be used with the solvent PPP model, we observe a good conservation of the BPTI structure along the trajectories. Moreover, our approach is able to provide a description of the protein solvation thermodynamic at the same accuracy as the standard Poisson-Boltzman continuum methods. It provides in addition a good description of the microscopic structural aspects concerning the solute/solvent interaction. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008 [source] Using web-based technology in laboratory instruction to reduce costsCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 4 2002Rita M. Powell Abstract The authors report the results of a project to reemphasize high quality, hands-on laboratory courses in the engineering curriculum while reducing their costs through the application of web-based teaching tools. The project resulted in substantial gains in productivity of faculty and staff, increased utilization of laboratory space, cost reductions in equipment, and improved quality of learning for our students. © 2003 Wiley Periodicals, Inc. Comput Appl Eng Educ 10: 204,214, 2002; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.10029 [source] Constraint-induced movement therapy (CIMT): Pediatric applicationsDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 2 2009Kathleen Brady Abstract The purpose of this article is to describe theoretical and research bases for constraint-induced movement therapy (CIMT), to discuss key features and variations in protocols currently in use with children, and to review the results of studies of efficacy. CIMT has been found to be an effective intervention for increasing functional use of the hemiparetic upper extremity in adults with chronic disability from stroke. CIMT developed out of behavioral research on the phenomenon of "learned nonuse" of an upper extremity, commonly observed following sensory and/or motor CNS injury, in which failure to regain use persists even after a period of partial recovery. CIMT includes three key elements: (1) constraining the use of the less-impaired upper extremity (UE); (2) intensive, repetitive daily therapist-directed practice of motor movements with the impaired UE for an extended period (2,3 weeks); and (3) shaping of more complex action patterns through a process of rewarding successive approximations to the target action. Mechanisms responsible for success are thought to be separate but complementary, that is, operant conditioning (reversal of learned nonuse) and experience-driven cortical reorganization. CIMT has recently been extended to children with hemiparesis secondary to perinatal stroke or other CNS pathology. Numerous case studies, as well as a small number of randomized controlled or controlled clinical trials have reported substantial gains in functional use of the hemiplegic UE following CIMT with children. Protocols vary widely in terms of type of constraint used, intensity and duration of training, and outcome measures. In general, all report gains in functional use, with minimal or no adverse effects. Continued research is needed, to clarify optimal protocol parameters and to further understand mechanisms of efficacy. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:102,111. [source] Myotendinous plasticity to ageing and resistance exercise in humansEXPERIMENTAL PHYSIOLOGY, Issue 3 2006N. D. Reeves The age-related loss of muscle mass known as senile sarcopenia is one of the main determinants of frailty in old age. Molecular, cellular, nutritional and hormonal mechanisms are at the basis of sarcopenia and are responsible for a progressive deterioration in skeletal muscle size and function. Both at single-fibre and at whole-muscle level, the loss of force exceeds that predicted by the decrease in muscle size. For single fibres, the loss of intrinsic force is mostly due to a loss in myofibrillar protein content. For whole muscle, in addition to changes in neural drive, alterations in muscle architecture and in tendon mechanical properties, exemplified by a reduction in tendon stiffness, have recently been shown to contribute to this phenomenon. Resistance training can, however, cause substantial gains in muscle mass and strength and provides a protective effect against several of the cellular and molecular changes associated with muscle wasting and weakness. In old age, not only muscles but also tendons are highly responsive to training, since an increase in tendon stiffness has been observed after a period of increased loading. Many of the myotendinous factors characterizing ageing can be at least partly reversed by resistance training. [source] Minimization of Nyquist ghosting for echo-planar imaging at ultra-high fields based on a "negative readout gradient" strategyJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2009Wietske van der Zwaag PhD Abstract Purpose: To improve the traditional Nyquist ghost correction approach in echo planar imaging (EPI) at high fields, via schemes based on the reversal of the EPI readout gradient polarity for every other volume throughout a functional magnetic resonance imaging (fMRI) acquisition train. Materials and Methods: An EPI sequence in which the readout gradient was inverted every other volume was implemented on two ultrahigh-field systems. Phantom images and fMRI data were acquired to evaluate ghost intensities and the presence of false-positive blood oxygenation level-dependent (BOLD) signal with and without ghost correction. Three different algorithms for ghost correction of alternating readout EPI were compared. Results: Irrespective of the chosen processing approach, ghosting was significantly reduced (up to 70% lower intensity) in both rat brain images acquired on a 9.4T animal scanner and human brain images acquired at 7T, resulting in a reduction of sources of false-positive activation in fMRI data. Conclusion: It is concluded that at high B0 fields, substantial gains in Nyquist ghost correction of echo planar time series are possible by alternating the readout gradient every other volume. J. Magn. Reson. Imaging 2009;30:1171,1178. © 2009 Wiley-Liss, Inc. [source] Deformation, mass transfer and mineral reactions in an eclogite facies shear zone in a polymetamorphic metapelite (Monte Rosa nappe, western Alps)JOURNAL OF METAMORPHIC GEOLOGY, Issue 2 2004L. M. Keller Abstract This study analyses the mineralogical and chemical transformations associated with an Alpine shear zone in polymetamorphic metapelites from the Monte Rosa nappe in the upper Val Loranco (N-Italy). In the shear zone, the pre-Alpine assemblage plagioclase + biotite + kyanite is replaced by the assemblage garnet + phengite + paragonite at eclogite facies conditions of about 650 °C at 12.5 kbar. Outside the shear zone, only minute progress of the same metamorphic reaction was attained during the Alpine metamorphic overprint and the pre-Alpine mineral assemblage is largely preserved. Textures of incomplete reaction, such as garnet rims at former grain contacts between pre-existing plagioclase and biotite, are preserved in the country rocks of the shear zone. Reaction textures and phase relations indicate that the Alpine metamorphic overprint occurred under largely anhydrous conditions in low strain domains. In contrast, the mineralogical changes and phase equilibrium diagrams indicate water saturation within the Alpine shear zones. Shear zone formation occurred at approximately constant volume but was associated with substantial gains in silica and losses in aluminium and potassium. Changes in mineral modes associated with chemical alteration and progressive deformation indicate that plagioclase, biotite and kyanite were not only consumed in the course of the garnet-and phengite-producing reactions, but were also dissolved ,congruently' during shear zone formation. A large fraction of the silica liberated by plagioclase, biotite and kyanite dissolution was immediately re-precipitated to form quartz, but the dissolved aluminium- and potassium-bearing species appear to have been stable in solution and were removed via the pore fluid. The reaction causes the localization of deformation by producing fine-grained white mica, which forms a mechanically weak aggregate. [source] Science inquiry and student diversity: Enhanced abilities and continuing difficulties after an instructional interventionJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 7 2006Okhee Lee This study examines elementary students' abilities to conduct science inquiry through their participation in an instructional intervention over a school year. The study involved 25 third and fourth grade students from six elementary schools representing diverse linguistic and cultural groups. Prior to and at the completion of the intervention, the students participated in elicitation sessions as they conducted a semistructured inquiry task on evaporation. The results indicate that students demonstrated enhanced abilities with some aspects of the inquiry task, but continued to have difficulties with other aspects of the task even after instruction. Although students from all demographic subgroups showed substantial gains, students from non-mainstream and less privileged backgrounds in science showed greater gains in inquiry abilities than their more privileged counterparts. The results contribute to the emerging literature on designing learning environments that foster science inquiry of elementary students from diverse backgrounds. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 43: 607,636, 2006 [source] Just do it? impact of a science apprenticeship program on high school students' understandings of the nature of science and scientific inquiryJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 5 2003Randy L. Bell The purpose of this study was to explicate the impact of an 8-week science apprenticeship program on a group of high-ability secondary students' understandings of the nature of science and scientific inquiry. Ten volunteers (Grades 10,11) completed a modified version of the Views of Nature of Science, Form B both before and after their apprenticeship to assess their conceptions of key aspects of the nature of science and scientific inquiry. Semistructured exit interviews provided an opportunity for students to describe the nature of their apprenticeship experiences and elaborate on their written questionnaire responses. Semistructured exit interviews were also conducted with the scientists who served as mentors for each of the science apprentices. For the most part, students held conceptions about the nature of science and scientific inquiry that were inconsistent with those described in current reforms. Participating science mentors held strong convictions that their apprentices had learned much about the scientific enterprise in the course of doing the science in their apprenticeship. Although most students did appear to gain knowledge about the processes of scientific inquiry, their conceptions about key aspects of the nature of science remained virtually unchanged. Epistemic demand and reflection appeared to be crucial components in the single case where a participant experienced substantial gains in her understandings of the nature of science and inquiry. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 487,509, 2003 [source] Maximum likelihood estimation of higher-order integer-valued autoregressive processesJOURNAL OF TIME SERIES ANALYSIS, Issue 6 2008Ruijun Bu Abstract., In this article, we extend the earlier work of Freeland and McCabe [Journal of time Series Analysis (2004) Vol. 25, pp. 701,722] and develop a general framework for maximum likelihood (ML) analysis of higher-order integer-valued autoregressive processes. Our exposition includes the case where the innovation sequence has a Poisson distribution and the thinning is binomial. A recursive representation of the transition probability of the model is proposed. Based on this transition probability, we derive expressions for the score function and the Fisher information matrix, which form the basis for ML estimation and inference. Similar to the results in Freeland and McCabe (2004), we show that the score function and the Fisher information matrix can be neatly represented as conditional expectations. Using the INAR(2) specification with binomial thinning and Poisson innovations, we examine both the asymptotic efficiency and finite sample properties of the ML estimator in relation to the widely used conditional least squares (CLS) and Yule,Walker (YW) estimators. We conclude that, if the Poisson assumption can be justified, there are substantial gains to be had from using ML especially when the thinning parameters are large. [source] Working memory deficits can be overcome: Impacts of training and medication on working memory in children with ADHDAPPLIED COGNITIVE PSYCHOLOGY, Issue 6 2010Joni Holmes This study evaluated the impact of two interventions,a training program and stimulant medication,on working memory (WM) function in children with attention deficit hyperactivity disorder (ADHD). Twenty-five children aged between 8 and 11 years participated in training that taxed WM skills to the limit for a minimum of 20 days, and completed other assessments of WM and IQ before and after training, and with and without prescribed drug treatment. While medication significantly improved visuo-spatial memory performance, training led to substantial gains in all components of WM across untrained tasks. Training gains associated with the central executive persisted over a 6-month period. IQ scores were unaffected by either intervention. These findings indicate that the WM impairments in children with ADHD can be differentially ameliorated by training and by stimulant medication. Copyright © 2009 John Wiley & Sons, Ltd. [source] Burden of disease attributable to selected environmental factors and injury among children and adolescents in EuropeCHILD: CARE, HEALTH AND DEVELOPMENT, Issue 6 2004Richard Reading Burden of disease attributable to selected environmental factors and injury among children and adolescents in Europe . ValentF, LittleD, BertolliniR, NemerLE, BarboneF & TamburliniG . ( 2004 ) Lancet , 363 , 2032 , 2039 . Background Environmental exposures contribute to the global burden of disease. We have estimated the burden of disease attributable to outdoor and indoor air pollution, inadequate water and sanitation, lead exposure, and injury among European children and adolescents. Methods Published studies and reports from international agencies were reviewed for calculation of risk-factor exposure in Europe. Disability-adjusted life years (DALYs) or deaths attributable to each factor, or both, were estimated by application of the potential impact fraction to the estimates of mortality and burden of disease from the WHO global database of burden of disease. Findings Among children aged 0,4 years, between 1.8% and 6.4% of deaths from all causes were attributable to outdoor air pollution; acute lower-respiratory-tract infections attributable to indoor air pollution accounted for 4.6% of all deaths and 3.1% of DALYs; and mild mental retardation resulting from lead exposure accounted for 4.4% of DALYs. In the age-group 0,14 years, diarrhoea attributable to inadequate water and sanitation accounted for 5.3% of deaths and 3.5% of DALYs. In the age-group 0,19 years, injuries were the cause of 22.6% of all deaths and 19.0% of DALYs. The burden of disease was much higher in European subregions B and C than subregion A. There was substantial uncertainty around some of the estimates, especially for outdoor air pollution. Interpretation Large proportions of deaths and DALYs in European children are attributable to outdoor and indoor air pollution, inadequate water and sanitation, lead exposure, and injuries. Interventions aimed at reducing children's exposure to environmental factors and injuries could result in substantial gains. The pronounced differences by subregion and age indicate the need for targeted action. [source] | |||||||||||||||||||