4,171 research outputs found
The Relationship between the Condition of Colorado Elementary School Facilities and Student Achievement
Research has shown conflicting results in the study of the relationship between student achievement and school facility condition. Much of the research has focused on specific aspects of the school facility or included the completion of surveys by school personnel. This study included a focus on the overall condition of school facilities according to the Facilities Conditions Index (FCI) as indicated in the Colorado Statewide Financial Assistance Priority Assessment conducted under the direction of the Colorado Department of Education (CDE) in fiscal year 2009-2010. The FCI was used as the independent variable while student achievement on the Colorado Student Assessment Program (CSAP) was used as the dependent variable. Hierarchical multiple regression (HMR) analyses were conducted to investigate the relationship between student achievement on the CSAP in reading, writing, and math and school facility conditions according to the FCI while controlling for English Language Learner (ELL), Special Education (SPED), and Free and Reduced Lunch (FRL) populations. Due to suggestions of multicollinearity between the control variables of ELL and FRL as well as minimal R² change values following the addition of the FCI into the models in the original analyses; 21 additional analyses were conducted which included control variable variations as well as simple bivariate or zero-order correlations. Consequently, 24 analyses were ran. The results of the three Hierarchical multiple regression (HMR) analyses in reading, writing, and math which addressed the original research questions indicated that one would fail to reject the null hypotheses and indicated that there is no relationship between student achievement on the Colorado Student Assessment Program (CSAP) and the Facilities Conditions Index (FCI) when controlling for English Language Learner (ELL), Special Education (SPED), and Free and Reduced Lunch (FRL) populations. These analyses found ELL, SPED, and FRL to be significant in explaining the variance in CSAP scores while the FCI was found not to be significant. The correlations between student achievement and ELL and FRL populations were strong while the correlations with SPED and the FCI were weak. Although weak, correlations revealed that greater percentages of students scoring proficient or advanced on the CSAP were associated with lower FCI indices or better facility conditions. Better student performance on the CSAP was also associated with lower percentages of ELL, SPED, and FRL populations. The correlations also revealed that the FCI is positively correlated with ELL, SPED, and FRL populations or that poorer facility conditions are associated with greater percentages of ELL, SPED, and FRL populations. The variable of Free and Reduced Lunch (FRL) population was found to be the greatest predictor of student achievement. The multiple analyses conducted indicated that student achievement on the CSAP in traditional Colorado public elementary schools and the Facilities Conditions Index (FCI), as an indicator of school facility condition, have a weak negative relationship and exhibit little shared variance. In other words, there is little to no relationship between school facility condition and student achievement
The coefficients of the characteristic polynomial in terms of the eigenvalues and the elements of an n×n matrix
AbstractThe coefficients of the characteristic polynomial of an n×n matrix are derived in terms of the eigenvalues and in terms of the elements of the matrix. The connection between the two expressions allows the sum of the products of all sets of k eigenvalues to be calculated using cofactors of the matrix
An efficient approach for the calculation of frequencies in macromolecules
I. INTRODUCTION. Conformational changes of macromolecules are essential in the understanding of e.g. proteins and drug design. The theoretical prediction is far from trivial, especially for large molecules. In many cases, collective motions are present which occur on a timescale (~ms) that is too long to be accessible through molecular dynamics simulations. Normal mode analysis (NMA) has been proven succesful in exploring the potential energy surface (PES) within the harmonic oscillator approximation.
The lowest frequency modes contribute the most to a conformational change. This paper presents a computationally attractive method that selects modes from the lower spectrum
Protein-Protein Docking Using Map Objects
Protein-protein docking is a molecular modeling strategy to predict biomolecular complexes and assemblies. Traditional protein-protein docking is performed at atomic resolution, which relies on X-ray and NMR experiments to provide structural information. When dealing with biomolecular assemblies of millions of atoms, atomic description of molecular objects becomes very computational inefficient. This article describes a development work that introduces map objects to molecular modeling studies to efficiently derive complex structures through map-map conformational search. This method has been implemented into CHARMM as the EMAP command and into AMBER in its SANDER program. This development enables molecular modeling and simulation to manipulate map objects, including map input, output, comparison, docking, etc. Through map objects, users can efficiently construct complex structures through protein-protein docking as well as from electron microscopy maps according to low map energies. Using a T-cell receptor (TCR) variable domain and acetylcholine binding protein (AChBP) as example systems, we showed the application to model an energetic optimized complex structure according to a complex map. The map objects serve as a bridge between high-resolution atomic structures and low-resolution image data
Structure and Dynamics of Macromolecular Assemblies from Electron Microscopy Maps
Electron microscopy (EM) and electron tomography (ET) have found extensive application to probe structural and dynamic properties of macromolecular assemblies. As an important complementary to X-ray and NMR in atomic structural determination, EM has reached a milestone resolution of 2.2Å, enough for understanding atomic interactions, interpreting mechanism of functions, and for structure-based drug design. This work describes approaches to derive structural information from EM/ET images and methods to study dynamics of macromolecular systems using EM/ET images as starting or ending targets. For low-resolution EM/ET maps, X-ray or NMR atomic structures of molecular components are needed to reduce the number of degrees of uncertainty. Depending on the resolution of EM/ET maps and the conformational differences from the X-ray or NMR structures, either rigid fitting or flexible fitting is used to obtain atomic structures. To illustrate the procedures of the atomic structure derivation, this work describes the core-weighted grid-threading Monte Carlo (CW-GTMC) rigid fitting and the map-restrained self-guided Langevin dynamics (MapSGLD) flexible fitting methods. Their applications are highlighted with four examples: architecture of an icosahedral pyruvate dehydrogenase complex, dynamics of a group II chaperonin, high-resolution structure of the cell-permeant inhibitor phenylethyl β-D-thiogalactopyranoside, and the mechanism of kinesin walking on microtube
Normal mode analysis of macromolecular systems with the Mobile Block Hessian method
Until recently, normal mode analysis (NMA) was limited to small proteins, not only because the required energy minimization is a computationally exhausting task, but also because NMA requires the expensive diagonalization of a 3Na 3Na matrix with Na the number of atoms. A series of simplified models has been proposed, in particular the Rotation-Translation Blocks (RTB) method by Tama et al. for the simulation of proteins. It makes use of the concept that a peptide chain or protein can be seen as a subsequent set of rigid components, i.e. the peptide units. A peptide chain is thus divided into rigid blocks with six degrees of freedom each.
Recently we developed the Mobile Block Hessian (MBH) method, which in a sense has similar features as the RTB method. The main difference is that MBH was developed to deal with partially optimized systems. The position/orientation of each block is optimized while the internal geometry is kept fixed at a plausible – but not necessarily optimized – geometry. This reduces the computational cost of the energy minimization. Applying the standard NMA on a partially optimized structure however results in spurious imaginary frequencies and unwanted coordinate dependence. The MBH avoids these unphysical effects by taking into account energy gradient corrections. Moreover the number of variables is reduced, which facilitates the diagonalization of the Hessian.
In the original implementation of MBH, atoms could only be part of one rigid block. The MBH is now extended to the case where atoms can be part of two or more blocks. Two basic linkages can be realized: (1) blocks connected by one link atom, or (2) by two link atoms, where the latter is referred to as the hinge type connection. In this work we present the MBH concept and illustrate its performance with the crambin protein as an example
Kenya research situation analysis on orphans and other vulnerable children
This item is archived in the repository for materials published for the USAID supported Orphans and Vulnerable Children Comprehensive Action Research Project (OVC-CARE) at the Boston University Center for Global Health and Development.Addressing the needs of orphans and vulnerable children (OVC) and mitigating negative outcomes of the growing OVC population worldwide is a high priority for national governments and international stakeholders that recognize this as an issue with social, economic, and human rights dimensions. Assembling the relevant available data on OVC in one place, and acknowledging the gaps that still exist in our knowledge, will assist policy makers and program implementers to make evidence-based decisions about how best to direct funding and program activities and maximize positive outcomes for children and their caretakers.
This Research Situation Analysis, Kenya Country Brief, presents a program-focused summary of available information on:
• The number of orphans and vulnerable children in Kenya.
• Current policies, programs and interventions designed and implemented to assist them.
• Gaps in these policies, programs and interventions.
• OVC research conducted between 2004 and 2008.
• Gaps in the Kenyan OVC evidence base.The Brief analyzes the available data for critical gaps in the national response and our understanding about whether current interventions are fulfilling the needs and improving the lives of vulnerable children. The report then recommends actions required to increase the knowledge base for improving the effectiveness and impact of OVC programs.The USAID | Project SEARCH, Orphans and Vulnerable Children Comprehensive Action Research (OVC-CARE) Task Order, is funded by the U.S. Agency for International Development under Contract No. GHH-I-00-07-00023-00, beginning August 1, 2008. OVC-CARE Task Order is implemented by Boston University. The opinions expressed herein are those of the authors and do not necessarily reflect the views of the funding agency
- …