9,852 research outputs found
Differences in Dropout Rates as a Function of High School Size for Students in Poverty: A Texas Multiyear, Statewide Study
Child poverty in the United States, with regard to student achievement, has grave challenges for the children who face poverty (Scott & Pressman, 2013). Not only is living in poverty associated with lower academic achievement, but student poverty is also associated with lower rates of school completion (Borg, Borg, & Stranahan, 2012; Cooper & Crosnoe, 2007; Kena et al., 2015). Consequentially, students who do not complete high school are more likely to (a) serve time in prison, (b) need government assistance, and/or ( c) die at an earlier age (Messacar & Oreopoulos, 2013). With the increasing number of children who are living in poverty, child poverty is an issue that needs to be at the forefront of the educational agenda (Tienken, 2012)
Grade Span Configuration and Academic Performance for Students in Poverty: A Texas Multiyear Analysis
Grade-span configuration refers to the range of grades within a school (Coladarci & Hancock, 2002). The debate over the benefits of one grade span configuration over the other has ensued for decades (Howley, 2002). Specific questions in this debate are (a) Which grade span configuration is most cost effective?; (b) Which grade span configuration yields the best academic achievement?; and (c) Which grade span configuration best meets the social and emotional needs of middle level children? (Howley, 2002)
Design and fabrication of chemically robust three-dimensional microfluidic valves
A current problem in microfluidics is that poly(dimethylsiloxane) (PDMS), used to fabricate many microfluidic devices, is not compatible with most organic solvents. Fluorinated compounds are more chemically robust than PDMS but, historically, it has been nearly impossible to construct valves out of them by multilayer soft lithography (MSL) due to the difficulty of bonding layers made of non-stick fluoropolymers necessary to create traditional microfluidic valves. With our new three-dimensional (3D) valve design we can fabricate microfluidic devices from fluorinated compounds in a single monolithic layer that is resistant to most organic solvents with minimal swelling. This paper describes the design and development of 3D microfluidic valves by molding of a perfluoropolyether, termed Sifel, onto printed wax molds. The fabrication of Sifel-based microfluidic devices using this technique has great potential in chemical synthesis and analysis
Differences in Reading Skills by Ethnicity/Race for Texas High School Students: A Statewide, Multiyear Examination
Analyzed in this study was the extent to which differences were present in the reading skills of Texas high school students as a function of ethnicity race i e Asian White Hispanic and Black Archival data were obtained from the Public Education Information Management System on all Texas high school students for the 2004-2005 through the 2011-2012 school years Statistically significant differences were present in reading skills by student ethnicity race in all 8 school years For all analyses average reading scores were lower for Black students than for Asian White and Hispanic students Similarly average reading scores were lower for Hispanic students than for Asian and White students Results were mixed for White and Asian students Implications for policy and for practice are discussed along with suggestions for future research Suggestions for future research and implications for policy and practice were mad
Adsorption of proteins to thin-films of PDMS and its effect on the adhesion of human endothelial cells
This paper describes a simple and inexpensive procedure to produce thin-films of poly(dimethylsiloxane). Such films were characterized by a variety of techniques (ellipsometry, nuclear magnetic resonance, atomic force microscopy, and goniometry) and used to investigate the adsorption kinetics of three model proteins (fibrinogen, collagen type-I, and bovine serum albumin) under different conditions. The information collected from the protein adsorption studies was then used to investigate the adhesion of human dermal microvascular endothelial cells. The results of these studies suggest that these films can be used to model the surface properties of microdevices fabricated with commercial PDMS. Moreover, the paper provides guidelines to efficiently attach cells in BioMEMS devices.Fil: Chumbimuni Torres, Karin Y.. The University of Texas at San Antonio; Estados UnidosFil: Coronado, Ramon E.. The University of Texas at San Antonio; Estados UnidosFil: Mfuh, Adelphe M.. The University of Texas at San Antonio; Estados UnidosFil: Castro Guerrero, Carlos. The University of Texas at San Antonio; Estados UnidosFil: Silva, MarĂa Fernanda. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de BiologĂa AgrĂcola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de BiologĂa AgrĂcola de Mendoza; ArgentinaFil: Negrete, George R.. The University of Texas at San Antonio; Estados UnidosFil: Bizios, Rena. The University of Texas at San Antonio; Estados UnidosFil: Garcia, Carlos D.. The University of Texas at San Antonio; Estados Unido
A new damage factor for seismic assessment of deficient bare and FRP-retrofitted RC structures
The seismic assessment of reinforced concrete (RC) structures before and after retrofitting is a challenging task, mainly because existing numerical tools cannot accurately model the evolution of concrete damage. This article proposes an innovative numerical method suitable to model and assess the ultimate carrying capacity of RC structures. The modelling approach proposes a steel constitutive material model with a damage factor that accounts for accumulated damage within the surrounding concrete domain, which effectively captures bar slippage. The proposed method is validated with experimental results from full-scale cyclic tests on deficient bare and CFRP-retrofitted RC joints tested previously by the authors. The results indicate that the proposed simulation method captures the extreme nonlinearities observed in the tested RC joints, with acceptable accuracy and computational robustness. The results of this study are expected to contribute towards the development of more reliable numerical tools and design guidelines for efficient seismic assessment of RC structures before and after earthquakes
A new damage factor for seismic assessment of deficient bare and FRP-retrofitted RC structures
The seismic assessment of reinforced concrete (RC) structures before and after retrofitting is a challenging task, mainly because existing numerical tools cannot accurately model the evolution of concrete damage. This article proposes an innovative numerical method suitable to model and assess the ultimate carrying capacity of RC structures. The modelling approach proposes a steel constitutive material model with a damage factor that accounts for accumulated damage within the surrounding concrete domain, which effectively captures bar slippage. The proposed method is validated with experimental results from full-scale cyclic tests on deficient bare and CFRP-retrofitted RC joints tested previously by the authors. The results indicate that the proposed simulation method captures the extreme nonlinearities observed in the tested RC joints, with acceptable accuracy and computational robustness. The results of this study are expected to contribute towards the development of more reliable numerical tools and design guidelines for efficient seismic assessment of RC structures before and after earthquakes
The Business Case for Racial Equity, 2013
Striving for racial equity -- a world where race is no longer a factor in the distribution of opportunity -- is a matter of social justice. But moving toward racial equity can generate significant economic returns as well. When people face barriers to achieving their full potential, the loss of talent, creativity, energy, and productivity is a burden not only for those disadvantaged, but for communities, businesses, governments, and the economy as a whole. Initial research on the magnitude of this burden in the United States (U.S.), as highlighted in this brief, reveals impacts in the trillions of dollars in lost earnings, avoidable public expenditures, and lost economic output
Cardiopulmonary Mortality and Fine Particulate Air Pollution by Species and Source in a National U.S. Cohort
The purpose of this study was to estimate cardiopulmonary mortality associations for long-term exposure to PM2.5 species and sources (i.e., components) within the U.S. National Health Interview Survey cohort. Exposures were estimated through a chemical transport model for six species (i.e., elemental carbon (EC), primary organic aerosols (POA), secondary organic aerosols (SOA), sulfate (SO4), ammonium (NH4), nitrate (NO3)) and five sources of PM2.5 (i.e., vehicles, electricity-generating units (EGU), non-EGU industrial sources, biogenic sources (bio), “other” sources). In single-pollutant models, we found positive, significant (p < 0.05) mortality associations for all components, except POA. After adjusting for remaining PM2.5 (total PM2.5 minus component), we found significant mortality associations for EC (hazard ratio (HR) = 1.36; 95% CI [1.12, 1.64]), SOA (HR = 1.11; 95% CI [1.05, 1.17]), and vehicle sources (HR = 1.06; 95% CI [1.03, 1.10]). HRs for EC, SOA, and vehicle sources were significantly larger in comparison to those for remaining PM2.5 (per unit μg/m3). Our findings suggest that cardiopulmonary mortality associations vary by species and source, with evidence that EC, SOA, and vehicle sources are important contributors to the PM2.5 mortality relationship. With further validation, these findings could facilitate targeted pollution regulations that more efficiently reduce air pollution mortality.This publication was developed as part of the Center for Air, Climate, and Energy Solutions (CACES), which was supported under Assistance Agreement No. R835873 awarded by the U.S. Environmental Protection Agency. It has not been formally reviewed by EPA. The views expressed in this document are solely those of authors and do not necessarily reflect those of the Agency. EPA does not endorse any products or commercial services mentioned in this publication. We also acknowledge support from the European Union’s Horizon 2020 Research and Innovation project REMEDIA under grant agreement No 874753.Peer Reviewed"Article signat per 13 autors/es:" Zachari A. Pond, Carlos S. Hernandez, Peter J. Adams, Spyros N. Pandis, George R. Garcia, Allen L. Robinson, Julian D. Marshall, Richard Burnett, Ksakousti Skyllakou, Pablo Garcia Rivera, Eleni Karnezi, Carver J. Coleman, C. Arden Pope III"Postprint (author's final draft
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