Changes in the Black-White Test score Gap in the Elementary School Grades. CSE Report 715

ERIC Educational Resources Information Center

Koretz, Daniel; Kim, Young-Suk

2007-01-01

In a pair of recent studies, Fryer and Levitt (2004a, 2004b) analyzed the Early Childhood Longitudinal Study--Kindergarten Cohort (ECLS-K) to explore the characteristics of the Black-White test score gap in young children. They found that the gap grew markedly between kindergarten and the third grade and that they could predict the gap from…

The Influence of Classroom Aggression and Classroom Climate on Aggressive-Disruptive Behavior

PubMed Central

Thomas, Duane E.; Bierman, Karen L.; Powers, CJ

2011-01-01

Research suggests that early classroom experiences influence the socialization of aggression. Tracking changes in the aggressive behavior of 4179 children from kindergarten to second-grade (ages 5–8) this study examined the impact of two important features of the classroom context–aggregate peer aggression and climates characterized by supportive teacher-student interactions. The aggregate aggression scores of children assigned to first-grade classrooms predicted the level of classroom aggression (assessed by teacher ratings) and quality of classroom climate (assessed by observers) that emerged by the end of grade 1. HLM analyses revealed that first-grade classroom aggression and quality of classroom climate made independent contributions to changes in student aggression, as students moved from kindergarten to second grade. Implications for policy and practice are discussed. PMID:21434887

Pavement Subsidence in the Cumberland Gap Tunnel, USA: A Story of Groundwater Chemistry

NASA Astrophysics Data System (ADS)

Zhu, J.; Currens, J. C.; Webb, S. E.; Rister, B. W.

2014-12-01

Cumberland Gap Tunnel was constructed in 1996 to improve highway travel between southeastern Kentucky and northeastern Tennessee and to restore Cumberland Gap to its historical appearance. About five years after construction, the concrete pavement in the tunnel began to exhibit noticeable signs of subsidence. Ground penetrating radar surveys detected voids in many areas of the limestone roadbed aggregate beneath the pavement. Field investigations conducted by the Kentucky Geological Survey and Kentucky Transportation Center from 2006 to 2008 discovered that groundwater was flowing from the bedrock invert into the aggregate along many parts of the tunnel. Average groundwater discharge from the tunnel was measured at approximately 1700 m3/d. We analyzed 265 groundwater samples collected from aggregate in different parts of the tunnel roadbed during low and high flow conditions. Calculated calcite saturation indices indicated that the groundwater was geochemically aggressive and capable of continuously dissolving calcite in the limestone aggregate although pH values of these water samples were near neutral. We also conducted an in-situ dissolution experiment by placing eight baskets filled with limestone aggregate beneath the roadbed in different locations in the tunnel for 178 days. At the end of the experiment, the limestone aggregate in contact with groundwater exhibited visual signs of dissolution and lost mass, and the highest mass loss recorded was 3.4 percent. Mass loss calculations based on kinetic models of calcite mineral and water samples taken near the baskets matched well with the actual measured mass losses, confirming that dissolution of calcite by the groundwater was the primary cause of the roadbed subsidence problem. Based on these findings, we suggested the limestone aggregate be replaced with noncarbonate (granite) aggregate to mitigate future road subsidence. The suggestion was adopted, and the repair was completed in early 2014.

Understanding the Fourth-Grade Slump: Our Point of View

ERIC Educational Resources Information Center

Sanacore, Joseph; Palumbo, Anthony

2009-01-01

Educators know that an achievement gap exists between students of low-income and middle-income families, a gap that is especially evident in fourth grade and beyond. This essay explores issues related to this gap, including primary-level children being immersed in narrative text and, therefore, unprepared for the challenges of informational text…

Gender and Minority Achievement Gaps in Science in Eighth Grade: Item Analyses of Nationally Representative Data. Research Report. ETS RR-17-36

ERIC Educational Resources Information Center

Qian, Xiaoyu; Nandakumar, Ratna; Glutting, Joseoph; Ford, Danielle; Fifield, Steve

2017-01-01

In this study, we investigated gender and minority achievement gaps on 8th-grade science items employing a multilevel item response methodology. Both gaps were wider on physics and earth science items than on biology and chemistry items. Larger gender gaps were found on items with specific topics favoring male students than other items, for…

Evaluation of Fine Aggregate Morphology by Image Method and Its Effect on Skid-Resistance of Micro-Surfacing.

PubMed

Xiao, Yue; Wang, Feng; Cui, Peide; Lei, Lei; Lin, Juntao; Yi, Mingwei

2018-05-29

Micro-surfacing is a widely used pavement preventive maintenance technology used all over the world, due to its advantages of fast construction, low maintenance cost, good waterproofness, and skid-resistance performance. This study evaluated the fine aggregate morphology and surface texture of micro-surfacing by AIMS (aggregate image measurement system), and explored the effect of aggregate morphology on skid-resistance of single-grade micro-surfacing. Sand patch test and British pendulum test were also used to detect skid-resistance for comparison with the image-based method. Wet abrasion test was used to measure skid-resistance durability for feasibility verification of single-grade micro-surfacing. The results show that the effect of Form2D on the skid-resistance of micro-surfacing is much stronger than that of angularity. Combining the feasibility analysis of durability and skid-resistance, 1.18⁻2.36 grade micro-surfacing meets the requirements of durability and skid-resistance at the same time. This study also determined that, compared with British pendulum test, the texture result obtained by sand patch test fits better with results of image method.

Preferential Charge Generation at Aggregate Sites in Narrow Band Gap Infrared Photoresponsive Polymer Semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sulas, Dana B.; London, Alexander E.; Huang, Lifeng

Infrared organic photodetector materials are investigated using transient absorption spectroscopy, demonstrating that ultrafast charge generation assisted by polymer aggregation is essential to compensate for the energy gap law, which dictates that excited state lifetimes decrease as the band gap narrows. Short sub–picosecond singlet exciton lifetimes are measured in a structurally related series of infrared–absorbing copolymers that consist of alternating cyclopentadithiophene electron–rich “push” units and strong electron–deficient “pull” units, including benzothiadiazole, benzoselenadiazole, pyridalselenadiazole, or thiadiazoloquinoxaline. While the ultrafast lifetimes of excitons localized on individual polymer chains suggest that charge carrier generation will be inefficient, high detectivity for polymer:PC 71BM infrared photodetectorsmore » is measured in the 0.6 < λ < 1.5 µm range. The photophysical processes leading to charge generation are investigated by performing a global analysis on transient absorption data of blended polymer:PC 71BM films. In these blends, charge carriers form primarily at polymer aggregate sites on the ultrafast time scale (within our instrument response), leaving quickly decaying single–chain excitons unquenched. Lastly, the results have important implications for the further development of organic infrared optoelectronic devices, where targeting processes such as excited state delocalization over aggregates may be necessary to mitigate losses to ultrafast exciton decay as materials with even lower band gaps are developed.« less

Preferential Charge Generation at Aggregate Sites in Narrow Band Gap Infrared Photoresponsive Polymer Semiconductors

DOE PAGES

Sulas, Dana B.; London, Alexander E.; Huang, Lifeng; ...

2018-02-13

Infrared organic photodetector materials are investigated using transient absorption spectroscopy, demonstrating that ultrafast charge generation assisted by polymer aggregation is essential to compensate for the energy gap law, which dictates that excited state lifetimes decrease as the band gap narrows. Short sub–picosecond singlet exciton lifetimes are measured in a structurally related series of infrared–absorbing copolymers that consist of alternating cyclopentadithiophene electron–rich “push” units and strong electron–deficient “pull” units, including benzothiadiazole, benzoselenadiazole, pyridalselenadiazole, or thiadiazoloquinoxaline. While the ultrafast lifetimes of excitons localized on individual polymer chains suggest that charge carrier generation will be inefficient, high detectivity for polymer:PC 71BM infrared photodetectorsmore » is measured in the 0.6 < λ < 1.5 µm range. The photophysical processes leading to charge generation are investigated by performing a global analysis on transient absorption data of blended polymer:PC 71BM films. In these blends, charge carriers form primarily at polymer aggregate sites on the ultrafast time scale (within our instrument response), leaving quickly decaying single–chain excitons unquenched. Lastly, the results have important implications for the further development of organic infrared optoelectronic devices, where targeting processes such as excited state delocalization over aggregates may be necessary to mitigate losses to ultrafast exciton decay as materials with even lower band gaps are developed.« less

Proportional Reasoning and Related Concepts: Analysis of Gaps and Understandings of Middle Grade Students

ERIC Educational Resources Information Center

Ojose, Bobby

2015-01-01

This study investigated proportional reasoning and the related concepts of decimal, percent, and ratio. In particular, the research focused on analyzing the gaps and understandings that grades 6, 7, and 8 students have and advanced factors for such gaps and understandings. The study employed a mixed method approach in which quantitative data was…

Geographic Variation of District-Level Gender Achievement Gaps within the United States

ERIC Educational Resources Information Center

Reardon, Sean; Fahle, Erin; Kalogrides, Demetra; Podolsky, Anne; Zarate, Rosalia

2016-01-01

Gender achievement gaps on national and state assessments have been a popular research topic over the last few decades. Many prior studies examine these gaps in different subjects (e.g., mathematics, reading, and science) and grades (typically kindergarten through eighth grade) for students living in various regions (typically states or countries)…

Band structures in fractal grading porous phononic crystals

NASA Astrophysics Data System (ADS)

Wang, Kai; Liu, Ying; Liang, Tianshu; Wang, Bin

2018-05-01

In this paper, a new grading porous structure is introduced based on a Sierpinski triangle routine, and wave propagation in this fractal grading porous phononic crystal is investigated. The influences of fractal hierarchy and porosity on the band structures in fractal graidng porous phononic crystals are clarified. Vibration modes of unit cell at absolute band gap edges are given to manifest formation mechanism of absolute band gaps. The results show that absolute band gaps are easy to form in fractal structures comparatively to the normal ones with the same porosity. Structures with higher fractal hierarchies benefit multiple wider absolute band gaps. This work provides useful guidance in design of fractal porous phononic crystals.

7 CFR 51.1837 - Classification of defects.

Code of Federal Regulations, 2010 CFR

2010-01-01

... STANDARDS) United States Standards for Grades of Florida Tangerines Definitions § 51.1837 Classification of....1828.] Deep or rough aggregating more than a circle 1/4 inch (6.4 mm) in diameter; slightly rough with... slight depth aggregating more than a circle 11/8 inches (28.6 mm) in diameter Deep or rough aggregating...

Gender Gap or Program Gap? Students' Negotiations of Study Practice in a Course in Electromagnetism

ERIC Educational Resources Information Center

Andersson, Staffan; Johansson, Anders

2016-01-01

This study of achievement differences, as reflected by course grades, on a third-semester electromagnetism course at a Swedish research university was motivated by instructor concerns about gender inequalities. Quantitative analysis showed a gender gap in course grades between female and male students for the period of fall 2007 to spring 2013.…

The influence of classroom aggression and classroom climate on aggressive-disruptive behavior.

PubMed

Thomas, Duane E; Bierman, Karen L; Powers, C J

2011-01-01

Research suggests that early classroom experiences influence the socialization of aggression. Tracking changes in the aggressive behavior of 4,179 children from kindergarten to second-grade (ages 5-8), this study examined the impact of 2 important features of the classroom context--aggregate peer aggression and climates characterized by supportive teacher-student interactions. The aggregate aggression scores of children assigned to first-grade classrooms predicted the level of classroom aggression (assessed by teacher ratings) and quality of classroom climate (assessed by observers) that emerged by the end of Grade 1. Hierarchical linear model analyses revealed that first-grade classroom aggression and quality of classroom climate made independent contributions to changes in student aggression, as students moved from kindergarten to second grade. Implications for policy and practice are discussed. © 2011 The Authors. Child Development © 2011 Society for Research in Child Development, Inc.

Detection of muscle gap by L-BIA in muscle injuries: clinical prognosis.

PubMed

Nescolarde, L; Yanguas, J; Terricabras, J; Lukaski, H; Alomar, X; Rosell-Ferrer, J; Rodas, G

2017-06-21

Sport-related muscle injury classifications are based basically on imaging criteria such as ultrasound (US) and magnetic resonance imaging (MRI) without consensus because of a lack of clinical prognostics for return-to-play (RTP), which is conditioned upon the severity of the injury, and this in turn with the muscle gap (muscular fibers retraction). Recently, Futbol Club Barcelona's medical department proposed a new muscle injury classification in which muscle gap plays an important role, with the drawback that it is not always possible to identify by MRI. Localized bioimpedance measurement (L-BIA) has emerged as a non-invasive technique for supporting US and MRI to quantify the disrupted soft tissue structure in injured muscles. To correlate the severity of the injury according to the gap with the RTP, through the percent of change in resistance (R), reactance (Xc) and phase-angle (PA) by L-BIA measurements in 22 muscle injuries. After grouping the data according to the muscle gap (by MRI exam), there were significant differences in R between grade 1 and grade 2f (myotendinous or myofascial muscle injury with feather-like appearance), as well as between grade 2f and grade 2g (myotendinous or myofascial muscle injury with feather and gap). The Xc and PA values decrease significantly between each grade (i.e. 1 versus 2f, 1 versus 2g and 2f versus 2g). In addition, the severity of the muscle gap adversely affected the RTP with significant differences observed between 1 and 2g as well as between 2f and 2g. These results show that L-BIA could aid MRI and US in identifying the severity of an injured muscle according to muscle gap and therefore to accurately predict the RTP.

The use of Crumb Rubber as Substitute of Fine Aggregate for Hot Asphalt Mixture using Polymer Modified Bitumen

NASA Astrophysics Data System (ADS)

Setyawan, A.; Nugroho, S. K.; Irsyad, A. M.; Mutaqo, H. F.; Ramadhan, P.; Sumarsono, A.; Pramesti, F. P.

2018-03-01

The development of road pavement to fulfilled the need of modern life is not only focused on heavy duty road, but also a light duty road for the convenience of road users according to its function. For example the use of pavement on the jogging track, rail crossing, playground and so on. Due to the need of an alternative and the innovation of a comfortable pavement layer, but sufficiently strong in holding the load on the layer. The alternative innovation that can be used for the respective requirement is the utilization of waste old tires as substitute material in pavement construction. In this case the use of crumb rubber made from old tire rubber as an 100% fine aggregate substitute on the asphalt mixtures is investigated. To improve the strength and durability of the mixtures, the addition of polymer modified bitumen was incorporated. The two types of asphalt mixture selected in this study by using a continuous gradation of asphalt concrete and a gap gradation of hot roll asphalt. Testing to be implemented in this research is volumetric characteristics, Marshall characteristics, resistance to abrasion and impact and permeability. Replacement of fine aggregate with crumb rubber on asphalt concrete mixture with 60/70 penetration grade bitumen and polymer modified asphalt SBS E-55 in this research are expected to be an alternative in improving the quality of pavement and overcoming the environmental problems by reuse the waste materials.

A PFC2D model of the interactions between the tire and the aggregate filled arrester bed on escape ramp

NASA Astrophysics Data System (ADS)

Qin, Pin-pin; Chen, Chui-ce; Pei, Shi-kang; Li, Xin

2017-06-01

The stopping distance of a runaway vehicle is determined by the entry speed, the design of aggregate-filled arrester bed and the longitudinal grade of escape ramp. Although numerous previous studies have been carried out on the influence of speed and grade on stopping distance, taking into account aggregate properties is rare. Firstly, this paper analyzes the interactions between the tire and the aggregate. The tire and the aggregate are abstracted into a big particle unit and a particle combination unit consisting of lots of aggregates, respectively. Secondly this paper proposes an assumption that this interaction is a kind of particle flow. Later, this paper uses some particle properties to describe the tire-particle unit and aggregate-particle unit respectively, then puts forward several simplified steps of modeling by particle flow code in 2 dimensions (PFC2D). Therefore, a PFC2D micro-simulation model of the interactions between the tire and the aggregate is proposed. The parameters of particle properties are then calibrated by three groups of numerical tests. The calibrated model is verified by eight full-scale arrester bed testing data to demonstrate its feasibility and accuracy. This model provides escape ramp designers a feasible simulation method not only for predicting the stopping distance but also considering the aggregate properties.

Classroom-Based Inequalities and Achievement Gaps in First Grade: The Role of Classroom Context and Access to Qualified and Effective Teachers

ERIC Educational Resources Information Center

Palardy, Gregory J.

2015-01-01

Background: An enduring question about achievement gaps is, which aspects of schools contribute most? At the early grade levels, when children spend the vast majority of their school day in a single classroom with a single teacher, school inequities that correlate with achievement gaps likely originate within the classroom. This study examined the…

Science Achievement Gaps by Gender and Race/Ethnicity in Elementary and Middle School: Trends and Predictors

ERIC Educational Resources Information Center

Quinn, David M.; Cooc, North

2015-01-01

Research on science achievement disparities by gender and race/ethnicity often neglects the beginning of the pipeline in the early grades. We address this limitation using nationally representative data following students from Grades 3 to 8. We find that the Black-White science test score gap (-1.07 SD in Grade 3) remains stable over these years,…

Evaluation of moisture-induced damage of dense graded and gap graded asphalt mixture with nanopolymer modified binder

NASA Astrophysics Data System (ADS)

Shaffie, E.; Arshad, A. K.; Ahmad, J.; Hashim, W.

2018-04-01

The purpose of this research is to study the moisture induce damage performance of dense graded (AC14) and stone mastic asphalt (SMA14) asphalt pavement using Nanolyacrylate polymer modified asphalt binder. The physical properties of aggregate, volumetric and performance of asphalt mixes were assessed and evaluated with the laboratory tests. The study investigates fourteenth different asphalt mixtures consisting of NP modified asphalt binder formulations at 2%, 4% and 6%. Two types of asphalt binder, penetration grade PEN 80-100 and performance grade PG 76 were added with Nanopolyacrylate as asphalt modifier. The modified asphalt binder was prepared by adding 6 percent of Nanopolyacrylate (NP) to the asphalt binder. Both AC14 and SMA14 mixtures passed the Marshall requirements which indicate that these mixtures were good with respect to durability and flexibility. In terms of moisture induce damage, it was observed that the strength of the asphalt mixes increased with the addition of NP polymer modified asphalt binder. Similar trend could also be seen for SMA14 mixes, where the ITS value of SMA14 showed a significant difference compared to AC14 and all the mixtures exceeded the minimum requirement value as specified in the specification. Thus, addition of nanopolyacrylate polymer to the asphalt binder has significantly improved the cohesion as well as adhesion properties of the asphalt binder, and hence the stripping performance. Therefore, it can be concluded that the nanopolyacylate is suitable to be used as a modifier to the modified asphalt binder in order to enhance the properties of the asphalt binder and thus improving the performance of asphalt in both AC14 and SMA14 mixes.

Social Norms in the Development of Adolescent Substance Use: A Longitudinal Analysis of the International Youth Development Study

PubMed Central

Eisenberg, Marla E.; Toumbourou, John W.; Catalano, Richard F.; Hemphill, Sheryl A.

2014-01-01

Identifying specific aspects of peer social norms that influence adolescent substance use may assist international prevention efforts. This study examines two aggregated measures of social norms in the school setting and their predictive association with substance (alcohol, tobacco and marijuana) use 2 years later in a large cross-national population-based cohort of adolescents. The primary hypothesis is that in Grade 7 both “injunctive” school norms (where students associate substance use with “coolness”) and “descriptive” norms (where student substance use is common) will predict Grade 9 substance use. Data come from the International Youth Development Study, including 2,248 students (51.2 % female) in the US and Australia attending 121 schools in Grade 7. Independent variables included injunctive norms (aggregating measures of school-wide coolness ratings of each substance use) and descriptive norms (aggregating the prevalence of school substance use) in Grade 7. Dependent variables included binge drinking and current use of alcohol, tobacco and marijuana in Grade 9. Associations between each type of school-wide social norm and substance use behaviors in Grade 9 were tested using multilevel logistic regression, adjusting for covariates. In unadjusted models, both injunctive and descriptive norms each significantly predicted subsequent substance use. In fully adjusted models, injunctive norms were no longer significantly associated with Grade 9 use, but descriptive norms remained significantly associated with tobacco and marijuana use in the expected direction. The findings identify descriptive social norms in the school context as a particularly important area to address in adolescent substance use prevention efforts. PMID:24633850

The Academic Achievement Gap: The Suburban Challenge. CSR Connection.

ERIC Educational Resources Information Center

Alson, Allan

Suburban schoolchildren of color, in the aggregate, do not perform as well as their white counterparts. In fact, the academic achievement gaps in many suburban communities are actually greater than those in urban school districts. This research brief looks at the achievement gap in suburban schools, offering preliminary answers to the following…

Effect of drainage in unbound aggregate bases on flexible pavement performance.

DOT National Transportation Integrated Search

2008-05-01

It has been well demonstrated that a positive subsurface drainage is beneficial in enhancing pavement performance and thus extending pavement service life. Typical permeable base materials include asphalt/cement-treated, open-graded aggregates and un...

Development of mix design procedures for gap-graded asphalt-rubber asphalt concrete

DOT National Transportation Integrated Search

2007-11-01

A research project was conducted to identify and document current modifications to ARIZONA 815c (75-blow Marshall method) used to develop gap-graded asphalt rubber asphalt concrete (GG AR AC) mix designs, and to develop and test improvements to provi...

Strain induced plasmon tuning in planar square-shaped aluminum nanoparticles array

NASA Astrophysics Data System (ADS)

Mokkath, Junais Habeeb

2018-06-01

Metal nanoparticle aggregate is an exciting platform for manipulating light-matter interactions at the nanoscale, thanks to the optically driven free electrons couple electrically across the inter-particle gap region. We use time dependent density functional theory calculations to investigate the optical response modulations in planar square-shaped aluminum nanoparticles array via morphology deformation (varying the inter-particle gap distance in the range of 2-20 Å) separately along one and two directions. We report the surprising observation that irrespective of the different morphology deformations, there exists a unique inter-particle gap distance of 12 Å for which, a maximum optical field enhancement can be achieved. We remark that plasmonic interaction between metal nanoparticles in an aggregate is controlled to a large extent by the size of the inter-particle gap distance. We believe that our quantum mechanical calculations will inspire and contribute to the design, control, and exploitation of aluminum based plasmonic devices.

Mechanical properties of recycled concrete with demolished waste concrete aggregate and clay brick aggregate

NASA Astrophysics Data System (ADS)

Zheng, Chaocan; Lou, Cong; Du, Geng; Li, Xiaozhen; Liu, Zhiwu; Li, Liqin

2018-06-01

This paper presents an experimental investigation on the effect of the replacement of natural coarse aggregate (NCA) with either recycled concrete aggregate (RCA) or recycled clay brick aggregate (RBA) on the compressive strengths of the hardened concrete. Two grades (C25 and C50) of concrete were investigated, which were achieved by using different water-to-cement ratios. In each grade concrete five different replacement rates, 0%, 25%, 50%, 75% and 100% were considered. In order to improve the performance of the recycled aggregates in the concrete mixes, the RCA and RBA were carefully sieved by using the optimal degradation. In this way the largest reduction in the 28-day compressive strength was found to be only 7.2% and 9.6% for C25 and C50 recycled concrete when the NCA was replaced 100% by RCA, and 11% and 13% for C25 and C50 recycled concrete when the NCA was replaced 100% by RBA. In general, the concrete with RCA has better performance than the concrete with RBA. The comparison of the present experimental results with those reported in literature for hardened concrete with either RCA or RBA demonstrates the effectiveness in improving the compressive strength by using the optimal gradation of recycled aggregates.

Use of wastes derived from earthquakes for the production of concrete masonry partition wall blocks.

PubMed

Xiao, Zhao; Ling, Tung-Chai; Kou, Shi-Cong; Wang, Qingyuan; Poon, Chi-Sun

2011-08-01

Utilization of construction and demolition (C&D) wastes as recycled aggregates in the production of concrete and concrete products have attracted much attention in recent years. However, the presence of large quantities of crushed clay brick in some the C&D waste streams (e.g. waste derived collapsed masonry buildings after an earthquake) renders the recycled aggregates unsuitable for high grade use. One possibility is to make use of the low grade recycled aggregates for concrete block production. In this paper, we report the results of a comprehensive study to assess the feasibility of using crushed clay brick as coarse and fine aggregates in concrete masonry block production. The effects of the content of crushed coarse and fine clay brick aggregates (CBA) on the mechanical properties of non-structural concrete block were quantified. From the experimental test results, it was observed that incorporating the crushed clay brick aggregates had a significant influence on the properties of blocks. The hardened density and drying shrinkage of the block specimens decreased with an increase in CBA content. The use of CBA increased the water absorption of block specimens. The results suggested that the amount of crushed clay brick to be used in concrete masonry blocks should be controlled at less than 25% (coarse aggregate) and within 50-75% for fine aggregates. Copyright © 2011 Elsevier Ltd. All rights reserved.

Performance comparison of various seal coat grades used in Texas.

DOT National Transportation Integrated Search

2012-07-01

This report documents research efforts to provide comparative quantitative performance information for various grades of seal coat aggregate available in the Texas Department of Transportations standard specifications. Length of service before rep...

Friction Angles of Open-Graded Aggregates from Large-Scale Direct Shear Testing : TechBrief

DOT National Transportation Integrated Search

2013-07-08

State and local transportation agencies frequently use opengraded aggregates for wall, roadway, and bridge construction. The primary advantages of using this type of material in wall and abutment applications are ease of constructability, lighter in-...

Achievement Gap Patterns of Grade 8 American Indian and Alaska Native Students in Reading and Math. Issues & Answers. REL 2009-No. 073

ERIC Educational Resources Information Center

Nelson, Steven; Greenough, Richard; Sage, Nicole

2009-01-01

Focusing on student proficiency in reading and math from 2003-04 to 2006-07, this report compares gaps in performance on state achievement tests between grade 8 American Indian and Alaska Native students and all other grade 8 students in 26 states serving large populations of American Indian and Alaska Native students. In response to a request by…

[Krigle estimation and its simulated sampling of Chilo suppressalis population density].

PubMed

Yuan, Zheming; Bai, Lianyang; Wang, Kuiwu; Hu, Xiangyue

2004-07-01

In order to draw up a rational sampling plan for the larvae population of Chilo suppressalis, an original population and its two derivative populations, random population and sequence population, were sampled and compared with random sampling, gap-range-random sampling, and a new systematic sampling integrated Krigle interpolation and random original position. As for the original population whose distribution was up to aggregative and dependence range in line direction was 115 cm (6.9 units), gap-range-random sampling in line direction was more precise than random sampling. Distinguishing the population pattern correctly is the key to get a better precision. Gap-range-random sampling and random sampling are fit for aggregated population and random population, respectively, but both of them are difficult to apply in practice. Therefore, a new systematic sampling named as Krigle sample (n = 441) was developed to estimate the density of partial sample (partial estimation, n = 441) and population (overall estimation, N = 1500). As for original population, the estimated precision of Krigle sample to partial sample and population was better than that of investigation sample. With the increase of the aggregation intensity of population, Krigel sample was more effective than investigation sample in both partial estimation and overall estimation in the appropriate sampling gap according to the dependence range.

Narrowing the Literacy Achievement Gap in Elementary Grades

ERIC Educational Resources Information Center

Dailey, Mary Callan

2014-01-01

This study addressed the gap in practice of instructional literacy, as evidenced by below-proficient literacy status by subgroups of regular education students in Grades 3-5 in an affluent suburban New Jersey public school district. The purpose of this qualitative grounded theory investigation, approached from an interpretive constructivist…

Calculation of Energy Diagram of Asymmetric Graded-Band-Gap Semiconductor Superlattices.

PubMed

Monastyrskii, Liubomyr S; Sokolovskii, Bogdan S; Alekseichyk, Mariya P

2017-12-01

The paper theoretically investigates the peculiarities of energy diagram of asymmetric graded-band-gap superlattices with linear coordinate dependences of band gap and electron affinity. For calculating the energy diagram of asymmetric graded-band-gap superlattices, linearized Poisson's equation has been solved for the two layers forming a period of the superlattice. The obtained coordinate dependences of edges of the conduction and valence bands demonstrate substantial transformation of the shape of the energy diagram at changing the period of the lattice and the ratio of width of the adjacent layers. The most marked changes in the energy diagram take place when the period of lattice is comparable with the Debye screening length. In the case when the lattice period is much smaller that the Debye screening length, the energy diagram has the shape of a sawtooth-like pattern.

Development of ODOT guidelines for the use of geogrids in aggregate bases.

DOT National Transportation Integrated Search

2012-11-01

A primary objective of the current study was to help ODOT expand its selection of approved : geogrid products for base reinforcement applications by producing measured data on selected : geogrids and a dense-graded base aggregate commonly used in ODO...

Thin film solar cell including a spatially modulated intrinsic layer

DOEpatents

Guha, Subhendu; Yang, Chi-Chung; Ovshinsky, Stanford R.

1989-03-28

One or more thin film solar cells in which the intrinsic layer of substantially amorphous semiconductor alloy material thereof includes at least a first band gap portion and a narrower band gap portion. The band gap of the intrinsic layer is spatially graded through a portion of the bulk thickness, said graded portion including a region removed from the intrinsic layer-dopant layer interfaces. The band gap of the intrinsic layer is always less than the band gap of the doped layers. The gradation of the intrinsic layer is effected such that the open circuit voltage and/or the fill factor of the one or plural solar cell structure is enhanced.

Open-graded wearing courses in the Pacific Northwest.

DOT National Transportation Integrated Search

2011-06-01

The Oregon Department of Transportation (ODOT) has been placing -inch nominal maximum aggregate size (NMAS) open-graded wearing courses (OGWCs) in structural layers of two inches or more for about 30 years. Despite this, OGWC performance in the Pac...

Performance evaluation of JRCP with stabilized open-graded drainage course.

DOT National Transportation Integrated Search

2009-08-01

From 1990 to 1995 the department used recycled concrete pavement as open-graded drainage course (OGDC) base : aggregate for thirteen concrete reconstruction projects. Overall, the JRCP projects with coated/stabilized OGDC have : performed very well i...

Subgroup Achievement and Gap Trends: Wyoming, 2010

ERIC Educational Resources Information Center

Center on Education Policy, 2010

2010-01-01

This paper profiles the student subgroup achievement and gap trends in Wyoming for 2010. Wyoming's demographic profile is such that achievement trends could only be determined for white, Latino, male and female, and low-income student subgroups. In grade 8 (the only grade in which subgroup trends were analyzed by achievement level), the white,…

Tunability of temperature dependent THz photonic band gaps in 1-D photonic crystals composed of graded index materials and semiconductor InSb

NASA Astrophysics Data System (ADS)

Singh, Bipin K.; Pandey, Praveen C.; Rastogi, Vipul

2018-05-01

Tunable temperature dependent terahertz photonic band gaps (PBGs) in one-dimensional (1-D) photonic crystal composed of alternating layers of graded index and semiconductor materials are demonstrated. Results show the influence of temperature, geometrical parameters, grading profile and material damping factor on the PBGs. Number of PBG increases with increasing the layer thickness and their bandwidth can be tuned with external temperature and grading parameters. Lower order band gap is more sensitive to the temperature which shows increasing trend with temperature, and higher order PBGs can also be tuned by controlling the external temperature. Band edges of PBGs are shifted toward higher frequency side with increasing the temperature. Results show that the operational frequencies of PBGs are unaffected when loss involved. This work enables to design tunable Temperature dependent terahertz photonic devices such as reflectors, sensors and filters etc.

Moral reasoning about great apes in research

NASA Astrophysics Data System (ADS)

Okamoto, Carol Midori

2006-04-01

This study explored how individuals (biomedical scientists, Great Ape Project activists, lay adults, undergraduate biology and environmental studies students, and Grade 12 and 9 biology students) morally judge and reason about using great apes in biomedical and language research. How these groups perceived great apes' mental capacities (e.g., pain, logical thinking) and how these perceptions related to their judgments were investigated through two scenarios. In addition, the kinds of informational statements (e.g., biology, economics) that may affect individuals' scenario judgments were investigated. A negative correlation was found between mental attributions and scenario judgments while no clear pattern occurred for the informational statements. For the biomedical scenario, all groups significantly differed in mean judgment ratings except for the biomedical scientists, GAP activists and Grade 9 students. For the language scenario, all groups differed except for the GAP activists, and undergraduate environmental studies and Grade 9 students. An in-depth qualitative analysis showed that although the biomedical scientists, GAP activists and Grade 9 students had similar judgments, they produced different mean percentages of justifications under four moral frameworks (virtue, utilitarianism, deontology, and welfare). The GAP activists used more virtue reasoning while the biomedical scientists and Grade 9 students used more utilitarian and welfare reasoning, respectively. The results are discussed in terms of developing environmental/humane education curricula.

The use of recycled concrete aggregate in a dense graded aggregate base course.

DOT National Transportation Integrated Search

2008-03-01

The research project was broken up into 2 different parts. The first part involved evaluating the potential use of the Time : Domain Reflectometry, TDR (ASTM D6780), as a non-nuclear means for determining the dry density and moisture content of : gra...

More Than One Million Children Served: Reading Recovery Results, 2000-2001.

ERIC Educational Resources Information Center

Reading Recovery Council of North America, Columbus, OH.

A key premise of Reading Recovery is that early intervention in first grade is critical in long-term literacy achievement because the gap between lowest- and highest-achieving children is narrow in lower grades but widens in later elementary school. Reading Recovery closes this gap at the critical time in children's literacy learning before the…

Cognitive Constraints and Island Effects

PubMed Central

Hofmeister, Philip; Sag, Ivan A.

2012-01-01

Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that non-structural manipulations that leave island structures intact can radically alter judgments of island violations. We argue here, building on work by Deane, Kluender, and others, that processing factors have the potential to account for this otherwise unexplained variation in acceptability judgments. We report the results of self-paced reading experiments and controlled acceptability studies which explore the relationship between processing costs and judgments of acceptability. In each of the three self-paced reading studies, the data indicate that the processing cost of different types of island violations can be significantly reduced to a degree comparable to that of non-island filler-gap constructions by manipulating a single non-structural factor. Moreover, this reduction in processing cost is accompanied by significant improvements in acceptability. This evidence favors the hypothesis that island-violating constructions involve numerous processing pressures that aggregate to drive processing difficulty above a threshold so that a perception of unacceptability ensues. We examine the implications of these findings for the grammar of filler-gap dependencies.* PMID:22661792

Development of the literacy achievement gap: a longitudinal study of kindergarten through third grade.

PubMed

Foster, Wayne A; Miller, Merideth

2007-07-01

The major goal of this study was to specify the developmental trajectories for phonics and early text comprehension skills of children from kindergarten through third grade. Data from the Early Childhood Longitudinal Study (N = 12,261) were used in this study. The participants were divided into 3 school readiness groups based on an assessment of literacy skill development at the time of entrance into kindergarten. The different groups were tracked on phonics and text comprehension development through the third grade. Students in the average and high literacy readiness groups achieved high scores in decoding (phonics) by the end of the first grade. Students in the low readiness group did not match these scores until the third grade. Although the phonics gap was essentially closed in the third grade, a second, very significant text comprehension gap was exposed. The 3 readiness groups were analyzed to assess the relative contributions of parent education, income, and kindergarten literacy score to third-grade literacy achievement. The results of this study stress the need for speech-language pathologists to assess emergent literacy skills in their speech and language clients and to include appropriate literacy goals in the treatment regimen as a means for reducing the potential need for identification as learning disabled in reading in the later years of elementary school.

The influence of fines on strength and drainage characteristics of aggregate bases.

DOT National Transportation Integrated Search

1996-01-01

One of the most commonly used dense-graded aggregate mixes in Virginia is designated as Type 2lB. In an effort to improve drainage characteristics of the 21B material it was proposed to decrease the maximum allowable percentage of fines from 7% to 5%...

Supercritical carbon dioxide fractionation of whey protein isolate for new food-grade ingredients

USDA-ARS?s Scientific Manuscript database

A new, environmentally benign whey protein fractionation process was developed using supercritical CO2 (SCO2) as an acid aggregating agent to separate a-lactalbumin (a-LA) aggregates from soluble beta-lactoglobulin (beta-LG) protein in concentrated whey protein isolate (WPI) solutions. The process e...

The Standardized Growth Expectation: Implications for Educational Evaluation.

ERIC Educational Resources Information Center

Stenner, A. Jackson; And Others

Three assumptions underlying the use of norm referenced tests are examined: (1) that expressing treatment effects in a standard score metric permits aggregation of effects across grades; (2) commonly used standardized tests are sufficiently comparable to permit aggregation of results across tests; and (3) the summer loss of achievement observed in…

Special Specification 3XXX, dense-graded hot-mix asphalt.

DOT National Transportation Integrated Search

2004-01-01

Construct a hot-mix asphalt (HMA) pavement layer composed of a compacted, dense-graded mixture of aggregate and asphalt binder mixed hot in a mixing plant. Pay adjustments will apply to HMA placed under this specification unless the HMA is deemed exe...

Designing, producing, and constructing fine-graded hot mix asphalt on Illinois roadways.

DOT National Transportation Integrated Search

2015-04-01

Fine-graded (F-G) asphalt concrete mixtures are composed of an aggregate structure in which the fine fraction controls the : load-carrying capacity of the mix. Other states have reported benefits in using F-G mixtures, including improved compaction, ...

Investigation of optimize graded concrete for Oklahoma : phase 1 : final report.

DOT National Transportation Integrated Search

2013-10-01

Optimized Graded Concrete has been a subject widely discussed through the history of concrete. Since aggregates make up over 70% of the volume in a mixture, gradation is critical to the strength, workability, and durability of concrete. In practice o...

Use of wastes derived from earthquakes for the production of concrete masonry partition wall blocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao Zhao; Faculty of Architecture, Civil Engineering and Environment Engineering and Mechanics, Sichuan University; Ling, Tung-Chai

2011-08-15

Highlights: > Solved the scientific and technological challenges impeding use of waste rubble derived from earthquake, by providing an alternative solution of recycling the waste in moulded concrete block products. > Significant requirements for optimum integration on the utilization of the waste aggregates in the production of concrete blocks are investigated. > A thorough understanding of the mechanical properties of concrete blocks made with waste derived from earthquake is reported. - Abstract: Utilization of construction and demolition (C and D) wastes as recycled aggregates in the production of concrete and concrete products have attracted much attention in recent years. However,more » the presence of large quantities of crushed clay brick in some the C and D waste streams (e.g. waste derived collapsed masonry buildings after an earthquake) renders the recycled aggregates unsuitable for high grade use. One possibility is to make use of the low grade recycled aggregates for concrete block production. In this paper, we report the results of a comprehensive study to assess the feasibility of using crushed clay brick as coarse and fine aggregates in concrete masonry block production. The effects of the content of crushed coarse and fine clay brick aggregates (CBA) on the mechanical properties of non-structural concrete block were quantified. From the experimental test results, it was observed that incorporating the crushed clay brick aggregates had a significant influence on the properties of blocks. The hardened density and drying shrinkage of the block specimens decreased with an increase in CBA content. The use of CBA increased the water absorption of block specimens. The results suggested that the amount of crushed clay brick to be used in concrete masonry blocks should be controlled at less than 25% (coarse aggregate) and within 50-75% for fine aggregates.« less

Development of maintenance practices for Oregon F-Mix : Interim report

DOT National Transportation Integrated Search

1999-08-01

The Oregon Department of Transportation (ODOT) produces an open-graded asphalt pavement(F-mix) unlike most open-graded pavements used in the United States. Its 25 mm maximum aggregate size and typical lift thickness of 50 mm is more like the porous a...

Compaction and measurement of field density for Oregon open-graded (F-MIX) asphalt pavement

DOT National Transportation Integrated Search

1999-06-01

A research project conducted by Oregon State University (OSU) and the Oregon Department of Transportation (ODOT) investigated compaction of Oregon F-mix asphalt pavement, an open-graded mix with 25-mm maximum size aggregate and air voids typically in...

Investigation of the Bailey Method for the design and analysis of dense-graded MHAC using Oregon aggregates.

DOT National Transportation Integrated Search

2007-09-01

Historically Oregon has specified gradations for dense-graded hot mix asphalt concrete (HMAC) using a combination of broadband limits and recommended ideal gradations. The recent adoption of SuperPave and Stone Matrix Asphalt (SMA) technolog...

Is the Black-White Achievement Gap a Public Sector Effect? An Examination of Student Achievement in the Third Grade

ERIC Educational Resources Information Center

Simms, Kathryn

2012-01-01

Prior research has suggested private school education in middle school and high school as a solution for the Black-White achievement gap. However, more recent research calls this solution into question. Additionally, research increasingly implicates third grade as being of preeminent importance in driving students' subsequent academic achievement.…

The costs of obesity in the workplace.

PubMed

Finkelstein, Eric A; DiBonaventura, Marco daCosta; Burgess, Somali M; Hale, Brent C

2010-10-01

To quantify per capita and aggregate medical expenditures and the value of lost productivity, including absenteeism and presenteeism, because of overweight, and grade I, II, and III obesity among U.S. employees. Cross-sectional analysis of the 2006 Medical Expenditure Panel Survey and the 2008 National Health and Wellness Survey. Among men, estimates range from -$322 for overweight to $6087 for grade III obese men. For women, estimates range from $797 for overweight to $6694 for grade III. In aggregate, the annual cost attributable to obesity among full-time employees is $73.1 billion. Individuals with a body mass index >35 represent 37% of the obese population but are responsible for 61% of excess costs. Successful efforts to reduce the prevalence of obesity, especially among those with a body mass index >35, could result in significant savings to employers.

Impact of grade separator on pedestrian risk taking behavior.

PubMed

Khatoon, Mariya; Tiwari, Geetam; Chatterjee, Niladri

2013-01-01

Pedestrians on Delhi roads are often exposed to high risks. This is because the basic needs of pedestrians are not recognized as a part of the urban transport infrastructure improvement projects in Delhi. Rather, an ever increasing number of cars and motorized two-wheelers encourage the construction of large numbers of flyovers/grade separators to facilitate signal free movement for motorized vehicles, exposing pedestrians to greater risk. This paper describes the statistical analysis of pedestrian risk taking behavior while crossing the road, before and after the construction of a grade separator at an intersection of Delhi. A significant number of pedestrians are willing to take risks in both before and after situations. The results indicate that absence of signals make pedestrians behave independently, leading to increased variability in their risk taking behavior. Variability in the speeds of all categories of vehicles has increased after the construction of grade separators. After the construction of the grade separator, the waiting time of pedestrians at the starting point of crossing has increased and the correlation between waiting times and gaps accepted by pedestrians show that after certain time of waiting, pedestrians become impatient and accepts smaller gap size to cross the road. A Logistic regression model is fitted by assuming that the probability of road crossing by pedestrians depends on the gap size (in s) between pedestrian and conflicting vehicles, sex, age, type of pedestrians (single or in a group) and type of conflicting vehicles. The results of Logistic regression explained that before the construction of the grade separator the probability of road crossing by the pedestrian depends on only the gap size parameter; however after the construction of the grade separator, other parameters become significant in determining pedestrian risk taking behavior. Copyright © 2012 Elsevier Ltd. All rights reserved.

Experimental collaboration for thick concrete structures with alkali-silica reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ezell, N Dianne Bull; Hayes, Nolan W.; Lenarduzzi, Roberto

Alkali-Silica Reaction (ASR) is a reaction that occurs over time in concrete between alkaline cement paste and reactive, non-crystalline silica in aggregates. An expansive gel is formed within the aggregates which results in micro-cracks in aggregates and adjacent cement paste. The reaction requires the presence of water and has been predominantly detected in groundwater-impacted portions of below grade structures, with limited impact to exterior surfaces in above grade structures. ASR can potentially affect concrete properties and performance characteristics such as compressive strength, modulus of elasticity, shear strength, and tensile strength. Since ASR degradation often takes significant amounts of time, developingmore » ASR detection techniques is important to the sustainability and extended operation lifetimes of nuclear power plants (NPPs). The University of Tennessee, Knoxville (UTK) in collaboration with Oak Ridge National Laboratory (ORNL) designed and built an experiment representative of typical NPP structures to study ASR in thick concrete structures.« less

Experimental collaboration for thick concrete structures with alkali-silica reaction

NASA Astrophysics Data System (ADS)

Ezell, N. Dianne Bull; Hayes, Nolan; Lenarduzzi, Roberto; Clayton, Dwight; Ma, Z. John; Le Pape, Sihem; Le Pape, Yann

2018-04-01

Alkali-Silica Reaction (ASR) is a reaction that occurs over time in concrete between alkaline cement paste and reactive, non-crystalline silica in aggregates. An expansive gel is formed within the aggregates which results in micro-cracks in aggregates and adjacent cement paste. The reaction requires the presence of water and has been predominantly detected in groundwater-impacted portions of below grade structures, with limited impact to exterior surfaces in above grade structures. ASR can potentially affect concrete properties and performance characteristics such as compressive strength, modulus of elasticity, shear strength, and tensile strength. Since ASR degradation often takes significant amounts of time, developing ASR detection techniques is important to the sustainability and extended operation lifetimes of nuclear power plants (NPPs). The University of Tennessee, Knoxville (UTK) in collaboration with Oak Ridge National Laboratory (ORNL) designed and built an experiment representative of typical NPP structures to study ASR in thick concrete structures.

3D contour fluorescence spectroscopy with Brus model: Determination of size and band gap of double stranded DNA templated silver nanoclusters

NASA Astrophysics Data System (ADS)

Kamalraj, Devaraj; Yuvaraj, Selvaraj; Yoganand, Coimbatore Paramasivam; Jaffer, Syed S.

2018-01-01

Here, we propose a new synthetic methodology for silver nanocluster preparation by using a double stranded-DNA (ds-DNA) template which no one has reported yet. A new calculative method was formulated to determine the size of the nanocluster and their band gaps by using steady state 3D contour fluorescence technique with Brus model. Generally, the structure and size of the nanoclusters determine by using High Resolution Transmission Electron Microscopy (HR-TEM). Before imaging the samples by using HR-TEM, they are introduced to drying process which causes aggregation and forms bigger polycrystalline particles. It takes long time duration and expensive methodology. In this current methodology, we found out the size and band gap of the nanocluster in the liquid form without any polycrystalline aggregation for which 3D contour fluorescence technique was used as an alternative approach to the HR-TEM method.

Evaluation of graded limestone base course on a low volume road : final report.

DOT National Transportation Integrated Search

1985-04-01

Due to decreasing supplies of native aggregate which may be incorporated into a base course, other materials need to be evaluated for constructibility and performance. To this end, a graded limestone base was constructed on a low volume road and eval...

Investigation of the Bailey Method for the design and analysis of dense-graded HMAC using Oregon aggregates : final report.

DOT National Transportation Integrated Search

2006-09-01

Historically Oregon has specified gradations for dense-graded hot mix asphalt concrete (HMAC) using a combination of broadband limits and recommended ideal gradations. The recent adoption of SuperPave and Stone Matrix Asphalt (SMA) technolog...

Band gap grading and photovoltaic performance of solution-processed Cu(In,Ga)S2 thin-film solar cells.

PubMed

Sohn, So Hyeong; Han, Noh Soo; Park, Yong Jin; Park, Seung Min; An, Hee Sang; Kim, Dong-Wook; Min, Byoung Koun; Song, Jae Kyu

2014-12-28

The photophysical properties of CuInxGa1-xS2 (CIGS) thin films, prepared by solution-based coating methods, are investigated to understand the correlation between the optical properties of these films and the electrical characteristics of solar cells fabricated using these films. Photophysical properties, such as the depth-dependent band gap and carrier lifetime, turn out to be at play in determining the energy conversion efficiency of solar cells. A double grading of the band gap in CIGS films enhances solar cell efficiency, even when defect states disturb carrier collection by non-radiative decay. The combinational stacking of different density films leads to improved solar cell performance as well as efficient fabrication because a graded band gap and reduced shunt current increase carrier collection efficiency. The photodynamics of minority-carriers suggests that the suppression of defect states is a primary area of improvement in CIGS thin films prepared by solution-based methods.

Five Factors Leading to Deaf and Hard of Hearing Students' Success: Perspectives of a Veteran Teacher

ERIC Educational Resources Information Center

Metz, Kelly K.

2017-01-01

Educators of deaf and hard of hearing students must close the gap that too often exists between a student's grade level and his or her actual achievement. Delays in developing and using English can lead naturally to delays in overall academic performance, and sometimes the gap between the student's grade level and his or her academic performance…

Collegiate Grading Practices and the Gender Pay Gap.

ERIC Educational Resources Information Center

Dowd, Alicia C.

2000-01-01

Presents a theoretical analysis showing that relatively low grading quantitative fields and high grading verbal fields create a disincentive for college women to invest in quantitative study. Extends research by R. Sabot and J. Wakeman-Linn. Models pressures on grading practices using higher education production functions. (Author/SLD)

Closing the Gap: An Overview. The Achievement Gap: An Overview. Info Brief. Number 44

ERIC Educational Resources Information Center

Poliakoff, Anne Rogers

2006-01-01

Persistent gaps between the academic achievements of different groups of children are thoroughly documented by the U.S. National Assessment of Educational Progress and other statistical analyses of state assessments, grades, course selection, and dropout rates. Despite improvements in some years, the gap endures as a consistent and disturbing…

Design of phononic band gaps in functionally graded piezocomposite materials by using topology optimization

NASA Astrophysics Data System (ADS)

Vatanabe, Sandro L.; Silva, Emílio C. N.

2011-04-01

One of the properties of composite materials is the possibility of having phononic band gaps, within which sound and vibrations at certain frequencies do not propagate. These materials are called Phononic Crystals (PCs). PCs with large band gaps are of great interest for many applications, such as transducers, elastic/ acoustic filters, noise control, and vibration shields. Most of previous works concentrates on PCs made of elastic isotropic materials; however, band gaps can be enlarged by using non-isotropic materials, such as piezoelectric materials. Since the main property of PCs is the presence of band gaps, one possible way to design structures which have a desired band gap is through Topology Optimization Method (TOM). TOM is a computational technique that determines the layout of a material such that a prescribed objective is maximized. Functionally Graded Materials (FGM) are composite materials whose properties vary gradually and continuously along a specific direction within the domain of the material. One of the advantages of applying the FGM concept to TOM is that it is not necessary a discrete 0-1 result, once the material gradation is part of the solution. Therefore, the interpretation step becomes easier and the dispersion diagram obtained from the optimization is not significantly modified. In this work, the main objective is to optimize the position and width of piezocomposite materials band gaps. Finite element analysis is implemented with Bloch-Floquet theory to solve the dynamic behavior of two-dimensional functionally graded unit cells. The results demonstrate that phononic band gaps can be designed by using this methodology.

Interaction of the Bragg gap with polaritonic gap in opal photonic crystals

NASA Astrophysics Data System (ADS)

Nayer, Eradat; Sivachenko, Andrey Yu; Li, Sergey; Raikh, Mikhail E.; Valy Vardeny, Z.

2001-03-01

Photonic crystals (PC) are a class of artificial structures with a periodic dielectric function. PCs can be a laboratory for testing fundamental processes involving interactions of radiation with matter in novel conditions. We have studied the optical properties of opal PCs that are infiltrated with highly polarizable media such as j-aggregates of cyanine dyes. Opals are self- assembled structures of silica (SiO_2) spheres. We report our studies on clarifying the relationship between a polaritonic gap and a photonic stop band (Bragg gap) when they resonantly coexist in the same structure. Infiltration of opal with polarizable molecules combines the polaritonic and Bragg diffractive effects. Both effects exist independently when the Bragg (at ω=ω_B) and polaritonic (at ω=ω_T) resonances are well separated in frequency. A completely different situation occurs when ωT =ω_B. Such a condition was achieved in opals that were infiltrated with J-aggregates of cyanine dyes that have large Rabi frequency. Our measurements show some dramatic changes in the shape of the reflectivity plateaus, which are due to the interplay between the photonic band gap and the polaritonic gap. The experimental results on reflectivity and its dependence on the light propagation angle and concentration of the cyanie dyes are in agreement with the theoretical calculations. (The work was supported in part by Army Research office DAAD19-00-1-0406.)

Grade determination of crumb rubber-modified performance graded asphalt binder.

DOT National Transportation Integrated Search

2013-08-01

Due to particulates common in crumb rubber-modified asphalt binders, conventional PG grading using the Dynamic Shear Rheometer (DSR) with a gap height of 1.0 mm may not be valid and in accordance with current specifications. Asphalt binder testing an...

Grade determination of crumb rubber-modified performance graded asphalt binder.

DOT National Transportation Integrated Search

2013-08-01

Due to particulates common in crumb rubber-modified asphalt binders, conventional PG grading using the Dynamic : Shear Rheometer (DSR) with a gap height of 1.0 mm may not be valid and in accordance with current specifications. : Asphalt binder testin...

Recreation/Transportation. B3. CHOICE: Challenging Options in Career Education.

ERIC Educational Resources Information Center

Putnam and Northern Westchester Counties Board of Cooperative Educational Services, Yorktown Heights, NY.

The documents aggregated here comprise the second grade unit of a career education curriculum for migrant children. The unit for grade 2 foucses on the fields of recreation and transportation. Travel agent, tour guide, camp counselor, coach, usher, school bus driver, airplane pilot, trucker, mover, railroad engineer, and astronaut are the 11 jobs…

TESTING OF INDOOR RADON REDUCTION TECHNIQUES IN CENTRAL OHIO HOUSES: PHASE 2 (WINTER 1988-1989)

EPA Science Inventory

The report gives results of tests of developmental indoor radon reduction techniques in nine slab-on-grade and four crawl-space houses near Dayton. Ohio. he slab-on-grade tests indicated that, when there is a good layer of aggregate under the slab, the sub-slab ventilation (SSV) ...

Does contact by a family nurse practitioner decrease early school absence?

PubMed

Kerr, Jill; Price, Marva; Kotch, Jonathan; Willis, Stephanie; Fisher, Michael; Silva, Susan

2012-02-01

Chronic early school absence (preschool through third grade) is associated with school failure. The presence of school nurses may lead to fewer absences, and nurse practitioners in school-based health centers (SBHCs) can facilitate a healthier population resulting in improved attendance. Efforts to get students back to school are unexplored in nursing literature. This article describes a nursing intervention to decrease early school absence in two elementary schools K-3 (N = 449) and a Head Start program (N = 130). The Head Start Family Nurse Practitioner (FNP) contacted families of chronically and excessively absent students by telephone, clinic visit at school, or home visit. The aggregate percentage attendance was evaluated by grades (preschool to third grade), schools (Head Start, Elementary Schools 1 and 2), and grades and schools and compared with publicly available school district aggregate data. There were statistically significant increases in attendance from Year 1 to Year 2 at p < .05 at the elementary level but not at the Head Start level. Student demographics, types of contacts, absence reasons (including sick child), and medical diagnoses are described.

Growing Bladder-Cancer Cells In Three-Dimensional Clusters

NASA Technical Reports Server (NTRS)

Spaulding, Glenn F.; Prewett, Tacey L.; Goodwin, Thomas J.

1995-01-01

Artificial growth process helps fill gaps in cancer research. Cell cultures more accurate as models for in vivo studies and as sources of seed cells for in vivo studies. Effected in horizontal rotating bioreactor described in companion article, "Simplified Bioreactor for Growing Mammalian Cells" (MSC-22060). Provides aggregates of cells needed to fill many of gaps.

Patterns of Change in U.S. Gender Achievement Gaps during Elementary and Middle School

ERIC Educational Resources Information Center

Fahle, Erin

2016-01-01

Research on gender achievement gaps shows they exist, and are largest in the tails of the distribution, starting as early as Kindergarten and persisting through eighth grade. In mathematics, studies find small average gender achievement gaps and larger systematically male-favoring gaps among the highest achieving students. This paper seeks to…

Functionalizing large nanoparticles for small gaps in dimer nanoantennas

NASA Astrophysics Data System (ADS)

Vietz, Carolin; Lalkens, Birka; Acuna, Guillermo P.; Tinnefeld, Philip

2016-04-01

The process of functionalizing gold nanoparticles with DNA commonly competes with nanoparticle aggregation, especially for larger particles of more than 80 nm diameter. Longer DNA strands reduce the tendency for aggregation but commonly lead to larger gaps when applied in certain geometrical arrangements such as gap nanoantennas. Here, we demonstrate that reversing the polarization of one of the strands for hybridization (yielding a zipper-like geometry) is sterically possible with uncompromised yields. Using the single dye molecule’s fluorescence lifetime as an indicator of the proximity of the nanoparticle in combination with electrodynamic simulations, we determine the distance between the nanoparticle and the dye placed in a DNA origami pillar. Importantly, compared to the common shear geometry smaller distances between the connected structures are obtained which are independent of the length of the DNA connector. Using the zipper geometry, we then arranged nanoparticles of 100 and 150 nm diameter on DNA origami and formed gap nanoantennas. We find that the previously reported trend of increased fluorescence enhancement of ATTO647N with increasing particle size for 20-100 nm nanoparticles is stopped. Gap nanoantennas built with 150 nm nanoparticles exhibit smaller enhancement than those with 100 nm nanoparticles. These results are discussed with the aid of electrodynamic simulations.

Delinquency in a Seventh-Grade Cohort: Impact of School Climate on Problem Behavior.

ERIC Educational Resources Information Center

Wright, William E.; Jesness, Carl F.

The relationship between delinquency and school climate is defined as the aggregate-belief-value characteristics of the people who make up the school. This relationship was investigated to determine if an aggregate measure of student attitudes about school, as measured bu the Quality of School Life Scale (QSL), can be used as a measure of the…

Improvement of band gap profile in Cu(InGa)Se{sub 2} solar cells through rapid thermal annealing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, D.S.; College of Mathematics and Physics, Shanghai University of Electric Power, Shanghai, 200090; Yang, J.

Highlights: • Proper RTA treatment can effectively optimize band gap profile to more expected level. • Inter-diffusion of atoms account for the improvement of the graded band gap profile. • The variation of the band gap profile created an absolute gain in the efficiency by 1.22%. - Abstract: In the paper, the effect of rapid thermal annealing on non-optimal double-graded band gap profiles was investigated by using X-ray photoelectron spectroscopy and capacitance–voltage measurement techniques. Experimental results revealed that proper rapid thermal annealing treatment can effectively improve band gap profile to more optimal level. The annealing treatment could not only reducemore » the values of front band gap and minimum band gap, but also shift the position of the minimum band gap toward front electrode and enter into space charge region. In addition, the thickness of Cu(InGa)Se{sub 2} thin film decreased by 25 nm after rapid thermal annealing treatment. All of these modifications were attributed to the inter-diffusion of atoms during thermal treatment process. Simultaneously, the variation of the band gap profile created an absolute gain in the efficiency by 1.22%, short-circuit current density by 2.16 mA/cm{sup 2} and filled factor by 3.57%.« less

Nanoscale studies link amyloid maturity with polyglutamine diseases onset

NASA Astrophysics Data System (ADS)

Ruggeri, F. S.; Vieweg, S.; Cendrowska, U.; Longo, G.; Chiki, A.; Lashuel, H. A.; Dietler, G.

2016-08-01

The presence of expanded poly-glutamine (polyQ) repeats in proteins is directly linked to the pathogenesis of several neurodegenerative diseases, including Huntington’s disease. However, the molecular and structural basis underlying the increased toxicity of aggregates formed by proteins containing expanded polyQ repeats remain poorly understood, in part due to the size and morphological heterogeneity of the aggregates they form in vitro. To address this knowledge gap and technical limitations, we investigated the structural, mechanical and morphological properties of fibrillar aggregates at the single molecule and nanometer scale using the first exon of the Huntingtin protein as a model system (Exon1). Our findings demonstrate a direct correlation of the morphological and mechanical properties of Exon1 aggregates with their structural organization at the single aggregate and nanometric scale and provide novel insights into the molecular and structural basis of Huntingtin Exon1 aggregation and toxicity.

Closing the Performance Gap: The Impact of the Early College High School Model on Underprepared Students

ERIC Educational Resources Information Center

Bernstein, Larry; Edmunds, Julie; Fesler, Lily

2014-01-01

Students entering high school in 9th grade face a formidable challenge. The transition to high school from 8th grade brings with it increased risks for all students. For example, students in 9th grade are anywhere from three to five times more likely to fail a class than students in any other grade. Similarly, ninth grade retention rates are…

Tunable graded rod laser assembly

NASA Technical Reports Server (NTRS)

AuYeung, John C. (Inventor)

1985-01-01

A tunable laser assembly including a pair of radially graded indexed optical segments aligned to focus the laser to form an external resonant cavity with an optical axis, the respective optical segments are retativity moveable along the optical axis and provide a variable et aion gap sufficient to permit variable tuning of the laser wavelength without altering the effective length of the resonant cavity. The gap also include a saturable absorbing material providing a passive mode-locking of the laser.

Understanding gaps between the risk perceptions of wildland-urban interface (WUI) residents and wildfire professionals

Treesearch

James R. Meldrum; Patricia A. Champ; Hannah Brenkert-Smith; Travis Warziniack; Christopher M. Barth; Lilia C. Falk

2015-01-01

Research across a variety of risk domains finds that the risk perceptions of professionals and the public differ. Such risk perception gaps occur if professionals and the public understand individual risk factors differently or if they aggregate risk factors into overall risk differently. The nature of such divergences, whether based on objective inaccuracies or on...

Grading Participation in College Courses: Instructor Attitudes and Practices

ERIC Educational Resources Information Center

Rogers, Susan L.

2011-01-01

An exploratory study was launched to redress a gap in the literature that is expressed as an assumption that "most" college instructors grade participation in undergraduate courses. A sample of 521 instructors at a large, northeastern public university was surveyed to assess their attitudes and practices in grading participation in…

Social feeding in Caenorhabditis elegans is modulated by antipsychotic drugs and calmodulin and may serve as a protophenotype for asociality.

PubMed

Dwyer, Donard S; Awatramani, Poonam; Thakur, Rashmi; Seeni, Ramya; Aamodt, Eric J

2015-05-01

Here, we define a protophenotype as an endophenotype that has been conserved during evolution. Social feeding in Caenorhabditis elegans may be an example of a protophenotype related to asociality in schizophrenia. It is regulated by the highly conserved neuropeptide Y receptor, NPR-1, and we speculated that social feeding should be affected by antipsychotic drugs. The social feeding strain, npr-1(g320), was exposed to antipsychotic drugs, dopamine or calmodulin antagonists on plates with bacterial lawns, and the number of aggregates on the plates was counted as a measure of social feeding. First-generation antipsychotics, chlorpromazine, trifluoperazine, fluphenazine, and haloperidol, and the second-generation drug, olanzapine, inhibited social feeding. Dopamine accelerated aggregation, whereas selective D2 dopamine receptor antagonists, sulpiride and raclopride, were inhibitory. Calmodulin antagonists effectively inhibited social feeding, as did RNAi knockdown of calmodulin (cmd-1) expression. In addition, gap junction inhibitors prevented aggregation, which is consistent with the hub-and-spoke arrangement of neurons that regulate social feeding via functional gap junctions. The studies described here revealed novel connections between dopaminergic signaling, the NPY receptor, calmodulin, and gap junctions in the regulation of social behavior in C. elegans. These pathways are evolutionarily-conserved, and have also been implicated in the pathogenesis of schizophrenia. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microstructure of the regions on a plane copper electrode surface affected by a spark discharge in air in the point-plane gap

NASA Astrophysics Data System (ADS)

Tren'kin, A. A.; Karelin, V. I.; Shibitov, Yu. M.; Blinova, O. M.; Yasnikov, I. S.

2017-09-01

The microstructure of the regions affected by spark discharge on the surface of a plane copper electrode in atmospheric air in the point-plane gap has been studied using a scanning electron microscope for both the positive and negative polarity of the point electrode. It has been found that the affected regions have the shape of round spots or groups of spots with diameters of individual spots varying in the range of 20-200 μm. It has been revealed that the spots have an internal spatial structure in the form of an aggregate of concentric rings. These rings are aggregates of a large number of microscopic craters with diameters of 0.1-1.0 μm.

An online detection system for aggregate sizes and shapes based on digital image processing

NASA Astrophysics Data System (ADS)

Yang, Jianhong; Chen, Sijia

2017-02-01

Traditional aggregate size measuring methods are time-consuming, taxing, and do not deliver online measurements. A new online detection system for determining aggregate size and shape based on a digital camera with a charge-coupled device, and subsequent digital image processing, have been developed to overcome these problems. The system captures images of aggregates while falling and flat lying. Using these data, the particle size and shape distribution can be obtained in real time. Here, we calibrate this method using standard globules. Our experiments show that the maximum particle size distribution error was only 3 wt%, while the maximum particle shape distribution error was only 2 wt% for data derived from falling aggregates, having good dispersion. In contrast, the data for flat-lying aggregates had a maximum particle size distribution error of 12 wt%, and a maximum particle shape distribution error of 10 wt%; their accuracy was clearly lower than for falling aggregates. However, they performed well for single-graded aggregates, and did not require a dispersion device. Our system is low-cost and easy to install. It can successfully achieve online detection of aggregate size and shape with good reliability, and it has great potential for aggregate quality assurance.

Comparison of marginal adaptation of mineral trioxide aggregate, glass ionomer cement and intermediate restorative material as root-end filling materials, using scanning electron microscope: An in vitro study

PubMed Central

Gundam, Sirisha; Patil, Jayaprakash; Venigalla, Bhuvan Shome; Yadanaparti, Sravanthi; Maddu, Radhika; Gurram, Sindhura Reddy

2014-01-01

Aim: The present study compares the marginal adaption of Mineral Trioxide Aggregate (MTA), Glass Ionomer Cement (GIC) and Intermediate Restorative Material (IRM) as root-end filling materials in extracted human teeth using Scanning Electron Microscope (SEM). Materials and Methods: Thirty single rooted human teeth were obturated with Gutta-percha after cleaning and shaping. Apical 3 mm of roots were resected and retrofilled with MTA, GIC and IRM. One millimeter transverse section of the retrofilled area was used to study the marginal adaptation of the restorative material with the dentin. Mounted specimens were examined using SEM at approximately 15 Kv and 10-6 Torr under high vacuum condition. At 2000 X magnification, the gap size at the material-tooth interface was recorded at 2 points in microns. Statistical Analysis: One way ANOVA Analysis of the data from the experimental group was carried out with gap size as the dependent variable, and material as independent variable. Results: The lowest mean value of gap size was recorded in MTA group (0.722 ± 0.438 μm) and the largest mean gap in GIC group (1.778 ± 0.697 μm). Conclusion: MTA showed least gap size when compared to IRM and GIC suggesting a better marginal adaptation. PMID:25506146

Ultra-high aggregate bandwidth two-dimensional multiple-wavelength diode laser arrays

NASA Astrophysics Data System (ADS)

Chang-Hasnain, Connie

1994-04-01

Two-dimensional (2D) multi-wavelength vertical cavity surface emitting laser (VCSEL) arrays is promising for ultrahigh aggregate capacity optical networks. A 2D VCSEL array emitting 140 distinct wavelengths was reported by implementing a spatially graded layer in the VCSEL structure, which in turn creates a wavelength spread. In this program, we concentrated on novel epitaxial growth techniques to make reproducible and repeatable multi-wavelength VCSEL arrays.

Recycling of rubble from building demolition for low-shrinkage concretes.

PubMed

Corinaldesi, Valeria; Moriconi, Giacomo

2010-04-01

In this project concrete mixtures were prepared that were characterized by low ductility due to desiccation by using debris from building demolition, which after a suitable treatment was used as aggregate for partial replacement of natural aggregates. The recycled aggregate used came from a recycling plant, in which rubble from building demolition was selected, crushed, cleaned, sieved, and graded. Such aggregates are known to be more porous as indicated by the Saturated Surface Dry (SSD) moisture content. The recycled concrete used as aggregates were added to the concrete mixture in order to study their influence on the fresh and hardened concrete properties. They were added either after water pre-soaking or in dry condition, in order to evaluate the influence of moisture in aggregates on the performance of concrete containing recycled aggregate. In particular, the effect of internal curing, due to the use of such aggregates, was studied. Concrete behavior due to desiccation under dehydration was studied by means of both drying shrinkage test and German angle test, through which shrinkage under the restrained condition of early age concrete can be evaluated. Copyright 2009 Elsevier Ltd. All rights reserved.

A physical description of the adhesion and aggregation of platelets

NASA Astrophysics Data System (ADS)

Chopard, Bastien; de Sousa, Daniel Ribeiro; Lätt, Jonas; Mountrakis, Lampros; Dubois, Frank; Yourassowsky, Catherine; Van Antwerpen, Pierre; Eker, Omer; Vanhamme, Luc; Perez-Morga, David; Courbebaisse, Guy; Lorenz, Eric; Hoekstra, Alfons G.; Boudjeltia, Karim Zouaoui

2017-04-01

The early stages of clot formation in blood vessels involve platelet adhesion-aggregation. Although these mechanisms have been extensively studied, gaps in their understanding still persist. We have performed detailed in vitro experiments, using the well-known Impact-R device, and developed a numerical model to better describe and understand this phenomenon. Unlike previous studies, we took into account the differential role of pre-activated and non-activated platelets, as well as the three-dimensional nature of the aggregation process. Our investigation reveals that blood albumin is a major parameter limiting platelet aggregate formation in our experiment. Simulations are in very good agreement with observations and provide quantitative estimates of the adhesion and aggregation rates that are hard to measure experimentally. They also provide a value of the effective diffusion of platelets in blood subject to the shear rate produced by the Impact-R.

Subgroup Achievement and Gap Trends: Idaho, 2010

ERIC Educational Resources Information Center

Center on Education Policy, 2010

2010-01-01

This paper profiles the student subgroup achievement and gap trends in Idaho for 2010. Idaho showed improvement in reading and math in grade 8 at the basic, proficient, and advanced levels for Latino and white students, low income students, and boys and girls. The state has also made progress in narrowing achievement gaps between Latino and white…

Behaviors of Teachers and Their Students in Schools with and without an Achievement Gap: An Observational Study

ERIC Educational Resources Information Center

Ratcliff, Nancy J.; Carroll, Kimberly L.; Jones, Cathy R.; Costner, Richard H.; Sheehan, Heather C.; Hunt, Gilbert H.

2017-01-01

This research shares findings from a year-long observational study to determine if there were significant differences in the identified behaviors of teachers and students in fourth and seventh grade classrooms in schools with an achievement gap versus those with no achievement gap. Specific research questions addressed types of instructional…

The role of planning skills in the income-achievement gap.

PubMed

Crook, Stephen R; Evans, Gary W

2014-01-01

The pervasive income-achievement gap has been attributed in part to deficiencies in executive functioning (EF). The development of EF is related to children's planning ability, an aspect of development that has received little attention. Longitudinal data from the National Institute of Child Health and Human Development study of early child care show that early childhood poverty (1 and 24 months) is significantly related to fifth grade, math, and reading achievement (n = 1,009). The ability to plan in Grade 3, indexed by the Tower of Hanoi task, mediates the income-achievement gap in math and to a lesser extent in reading. IQ was incorporated as a statistical control throughout. © 2013 The Authors. Child Development © 2013 Society for Research in Child Development, Inc.

Sputtering-growth of seeded Au nanoparticles for nanogap-assisted surface-enhanced Raman scattering (SERS) biosensing

NASA Astrophysics Data System (ADS)

Fu, Chit Yaw; U. S., Dinish; Rautela, Shashi; Goh, Douglas Wenda; Olivo, Malini

2011-12-01

Gold-coated array patterned with tightly-packed nanospheres was developed as a substrate base for constructing SERSenriched nanogaps with Au-nanoparticles (GNPs). Using 1,2-ethanedithiol as a linker, Au-NPs (=17-40nm) were anchored covalently on the sphere-array. Thin Au layer was sputtered on the substrate to mask the citrate coating of GNPs that could demote the sensing mechanism. The negatively-charged GNP surface warrants the colloidal stability, but the resulting repulsive force keeps the immobilized NPs apart by about 40nm. The attained gap size is inadequately narrow to sustain any intense enhancement owing to the near-field nature of SERS. Minimal amount of NaCl was then added to slightly perturb the colloidal stability by reducing their surface charge. Notably, the interparticle-gap reduces at increasing amount of salt, giving rise to increased packing density of GNPs. The SERS enhancement is also found to exponentially increase at decreasing gap size. Nevertheless, the minimum gap achieved is limited to merely 7nm. Excessive addition of salt would eventually induce complete aggregation of particles, forming clustered NPs on the array. A simple sputtering-growth approach is therefore proposed to further minimize the interparticle gap by enlarging the seeded NPs based on mild sputtering. The SEM images confirm that the gap below 7nm is achievable. With advent of the colloidal chemistry, the combined salt-induced aggregation and sputtering-growth techniques can be applied to engineer interparticle gap that is crucial to realize an ultrasensitive SERS biosensor. The proposed two-step preparation can be potentially adopted to fabricate the SERS-enriched nanogaps on the microfluidics platform.

Within-Day Variability in the Quality of Classroom Interactions during Third and Fifth Grade: Implications for Children's Experiences and Conducting Classroom Observations

ERIC Educational Resources Information Center

Curby, Timothy W.; Stuhlman, Megan; Grimm, Kevin; Mashburn, Andrew; Chomat-Mooney, Lia; Downer, Jason; Hamre, Bridget; Pianta, Robert C.

2011-01-01

The quality of classroom interactions has typically been studied using aggregates of ratings over time. However, within-day ratings may contain important variability. This study investigated within-day variability using the NICHD Study of Early Childcare and Youth Development's observational data during grades 3 and 5. The first question examined…

Group living in squamate reptiles: a review of evidence for stable aggregations.

PubMed

Gardner, Michael G; Pearson, Sarah K; Johnston, Gregory R; Schwarz, Michael P

2016-11-01

How sociality evolves and is maintained remains a key question in evolutionary biology. Most studies to date have focused on insects, birds, and mammals but data from a wider range of taxonomic groups are essential to identify general patterns and processes. The extent of social behaviour among squamate reptiles is under-appreciated, yet they are a promising group for further studies. Living in aggregations is posited as an important step in the evolution of more complex sociality. We review data on aggregations among squamates and find evidence for some form of aggregations in 94 species across 22 families. Of these, 18 species across 7 families exhibited 'stable' aggregations that entail overlapping home ranges and stable membership in long-term (years) or seasonal aggregations. Phylogenetic analysis suggests that stable aggregations have evolved multiple times in squamates. We: (i) identify significant gaps in our understanding; (ii) outline key traits which should be the focus of future research; and (iii) outline the potential for utilising reproductive skew theory to provide insights into squamate sociality. © 2015 Cambridge Philosophical Society.

Incorporating Early Learning Strategies in the School Improvement Grants (SIG) Program: How Three Schools Integrated Early Childhood Strategies into School Turnaround Efforts to Improve Instruction for All Students

ERIC Educational Resources Information Center

Connors-Tadros, Lori; Dunn, Lenay; Martella, Jana; McCauley, Carlas

2015-01-01

A significant body of research shows that achievement gaps evident in persistently low-performing schools, in many instances, manifest prior to children entering kindergarten. High-quality early learning programs have proven to demonstrate positive effects on closing academic gaps both for individual children and in the aggregate for the school.…

Principals and School Counselors: Separate Entities in Identifying Achievement Gaps in College Readiness for African American Students With Disabilities

ERIC Educational Resources Information Center

Roberts, Laura A.; Bouknight, Tamisha M.

2015-01-01

This case illustrates an example of how one school relied solely on aggregate data and failed to address the college readiness needs of African American students with disabilities. However, the way in which the school counselor identified this opportunity gap may not have been the most ethical approach, and now she is faced with a dilemma. This…

Sex Matters Less for Younger Faculty: Evidence of Desegregate Pay Disparities from the 1988 and 1993 NCES Surveys.

ERIC Educational Resources Information Center

Toutkoushian, Robert K.

1998-01-01

Uses data from 1988 and 1993 National Center for Education Statistics surveys of faculty to examine what has happened to earnings of women in higher education. Data show the aggregate unexplained wage gap between men and women is between 7% and 10%. Wage gap for younger women is much lower than for older women in academe, suggesting some progress…

Do Gender and Physical Attractiveness Affect College Grades?

ERIC Educational Resources Information Center

Krawczyk, Michal

2018-01-01

In this study, data on grades awarded for bachelor and master theses at a large Polish university were used to identify possible discrimination on gender or physical attractiveness. The focus is on the gap between the grades awarded by the advisor (who knows the student personally) and the referee (who typically does not, so that gender is less…

End-of-Grade (EOG) Multiple-Choice Test Results, 2008-09. Measuring Up. E&R Report No. 10.12

ERIC Educational Resources Information Center

McMillen, Brad

2010-01-01

In 2008-09, results from End-of-Grade (EOG) reading and mathematics tests in WCPSS continued to demonstrate an upward trend across grade levels and student subgroups. Disaggregation of results by ethnicity, income level, disability status, and English proficiency status showed that achievement gaps between historically underperforming subgroups…

Excitations in opal photonic crystals infiltrated with polarizable media

NASA Astrophysics Data System (ADS)

Eradat, Nayer; Sivachenko, A. Y.; Raikh, Mikhail E.; Vardeny, Z. Valy; Zakhidov, Anvar A.; Li, S.; Baughman, Ray H.

2002-12-01

Photonic crystals (PC) are a class of artificial structures with a periodic dielectric function. PCs can be a laboratory for testing fundamental processes involving interactions of radiation with matter in novel conditions. We have studied the optical properties of opal PCs that are infiltrated with highly polarizable media such as j-aggregates of cyanine dyes. Opals are self-assembled structures of silica spheres. We report our studies on clarifying the relationship between a polaritonic gap and a photonic stop band (Bragg gap) when they resonantly coexist in the same structure. Infiltration of opal with polarizable molecules combines the polaritonic and Bragg diffractive effects. Both effects exist independently when the Bragg (at ω = ωB) and polaritonic (ω = ωT) resonances are well separated in frequency. A completely different situation occurs when ωT ~ωB. Such a condition was achieved in opals that were infiltrated with J-aggregates of cyanine dyes that have large Rabi frequency. Our measurements show some dramatic changes in the shape of the reflectivity plateaus, which are due to the interplay between the photonic band gap and the polaritonic gap. The experimental results on reflectivity and its dependence on the light propagation angle and concentration of the cyanie dyes are in agreement with the theoretical calculations.

Tunneling calculations for GaAs-Al(x)Ga(1-x) as graded band-gap sawtooth superlattices. Thesis

NASA Technical Reports Server (NTRS)

Forrest, Kathrine A.; Meijer, Paul H. E.

1991-01-01

Quantum mechanical tunneling calculations for sawtooth (linearly graded band-gap) and step-barrier AlGaAs superlattices were performed by means of a transfer matrix method, within the effective mass approximation. The transmission coefficient and tunneling current versus applied voltage were computed for several representative structures. Particular consideration was given to effective mass variations. The tunneling properties of step and sawtooth superlattices show some qualitative similarities. Both structures exhibit resonant tunneling, however, because they deform differently under applied fields, the J-V curves differ.

Gap junctions contribute to anchorage-independent clustering of breast cancer cells.

PubMed

Gava, Fabien; Rigal, Lise; Mondesert, Odile; Pesce, Elise; Ducommun, Bernard; Lobjois, Valérie

2018-02-27

Cancer cell aggregation is a key process involved in the formation of clusters of circulating tumor cells. We previously reported that cell-cell adhesion proteins, such as E-cadherin, and desmosomal proteins are involved in cell aggregation to form clusters independently of cell migration or matrix adhesion. Here, we investigated the involvement of gap junction intercellular communication (GJIC) during anchorage-independent clustering of MCF7 breast adenocarcinoma cells. We used live cell image acquisition and analysis to monitor the kinetics of MCF7 cell clustering in the presence/absence of GJIC pharmacological inhibitors and to screen a LOPAC® bioactive compound library. We also used a calcein transfer assay and flow cytometry to evaluate GJIC involvement in cancer cell clustering. We first demonstrated that functional GJIC are established in the early phase of cancer cell aggregation. We then showed that pharmacological inhibition of GJIC using tonabersat and meclofenamate delayed MCF7 cell clustering and reduced calcein transfer. We also found that brefeldin A, an inhibitor of vesicular trafficking, which we identified by screening a small compound library, and latrunculin A, an actin cytoskeleton-disrupting agent, both impaired MCF7 cell clustering and calcein transfer. Our results demonstrate that GJIC are involved from the earliest stages of anchorage-independent cancer cell aggregation. They also give insights into the regulatory mechanisms that could modulate the formation of clusters of circulating tumor cells.

Development of construction materials using nano-silica and aggregates recycled from construction and demolition waste.

PubMed

Mukharjee, Bibhuti Bhusan; Barai, Sudhirkumar V

2015-06-01

The present work addresses the development of novel construction materials utilising commercial grade nano-silica and recycled aggregates retrieved from construction and demolition waste. For this, experimental work has been carried out to examine the influence of nano-silica and recycled aggregates on compressive strength, modulus of elasticity, water absorption, density and volume of voids of concrete. Fully natural and recycled aggregate concrete mixes are designed by replacing cement with three levels (0.75%, 1.5% and 3%) of nano-silica. The results of the present investigation depict that improvement in early days compressive strength is achieved with the incorporation of nano-silica in addition to the restoration of reduction in compressive strength of recycled aggregate concrete mixes caused owing to the replacement of natural aggregates by recycled aggregates. Moreover, the increase in water absorption and volume of voids with a reduction of bulk density was detected with the incorporation of recycled aggregates in place of natural aggregates. However, enhancement in density and reduction in water absorption and volume of voids of recycled aggregate concrete resulted from the addition of nano-silica. In addition, the results of the study reveal that nano-silica has no significant effect on elastic modulus of concrete. © The Author(s) 2015.

Gender Gap Trends on Mathematics Exams Position Girls and Young Women for STEM Careers

ERIC Educational Resources Information Center

Beekman, John A.; Ober, David

2015-01-01

Nine years of results on 4.2 million of Indiana's Indiana Statewide Testing for Educational Progress (ISTEP) mathematics (math) exams (grades 3-10) taken after the implementation of No Child Left Behind have been used to determine gender gaps and their associated trends. Sociocultural factors were investigated by comparing math gender gaps and gap…

The Gender Gap in Student Engagement: The Role of Teachers' Autonomy Support, Structure, and Involvement

ERIC Educational Resources Information Center

Lietaert, Sofie; Roorda, Debora; Laevers, Ferre; Verschueren, Karine; De Fraine, Bieke

2015-01-01

Background: The gender gap in education in favour of girls is a widely known phenomenon. Boys generally have higher dropout rates, obtain lower grades, and show lower engagement. Insight into factors related to these academic outcomes could help to address the gender gap. Aims: This study investigated, for Dutch language classes, (1) how boys and…

The Black-White Test Score Gap through Third Grade. NBER Working Paper No. 11049

ERIC Educational Resources Information Center

Fryer, Roland G.; Levitt, Steven D.

2005-01-01

This paper describes basic facts regarding the black-white test score gap over the first four years of school. Black children enter school substantially behind their white counterparts in reading and math, but including a small number of covariates erases the gap. Over the first four years of school, however, blacks lose substantial ground…

Increasing Student Performance on the Independent School Entrance Exam (ISEE) Using the Gap Analysis Approach

ERIC Educational Resources Information Center

Sarshar, Shanon Etty

2013-01-01

Using the Gap Analysis problem-solving framework (Clark & Estes, 2008), this study examined the performance gap experienced by 6th grade students on the math sections of the ISEE (Independent School Entrance Exam). The purpose of the study was to identify and validate the knowledge, motivation, and organization causes of the students' low…

Decreasing the Gap: Understanding the Role of READ 180 in Helping to Decrease the Achievement Gap for Middle School Students

ERIC Educational Resources Information Center

Neubert, Emily Sarah

2017-01-01

As federal mandates continue to emphasize the use of standardized tests, academic research is needed to determine if reading intervention programs are helping to close the achievement gap between struggling readers and their grade level peers. Although previous research indicated that reading intervention can be an effective tool for increasing…

Altered glutamyl-aminopeptidase activity and expression in renal neoplasms

PubMed Central

2014-01-01

Background Advances in the knowledge of renal neoplasms have demonstrated the implication of several proteases in their genesis, growth and dissemination. Glutamyl-aminopeptidase (GAP) (EC. 3.4.11.7) is a zinc metallopeptidase with angiotensinase activity highly expressed in kidney tissues and its expression and activity have been associated wtih tumour development. Methods In this prospective study, GAP spectrofluorometric activity and immunohistochemical expression were analysed in clear-cell (CCRCC), papillary (PRCC) and chromophobe (ChRCC) renal cell carcinomas, and in renal oncocytoma (RO). Data obtained in tumour tissue were compared with those from the surrounding uninvolved kidney tissue. In CCRCC, classic pathological parameters such as grade, stage and tumour size were stratified following GAP data and analyzed for 5-year survival. Results GAP activity in both the membrane-bound and soluble fractions was sharply decreased and its immunohistochemical expression showed mild staining in the four histological types of renal tumours. Soluble and membrane-bound GAP activities correlated with tumour grade and size in CCRCCs. Conclusions This study suggests a role for GAP in the neoplastic development of renal tumours and provides additional data for considering the activity and expression of this enzyme of interest in the diagnosis and prognosis of renal neoplasms. PMID:24885240

The Operation of Grade Retention and Educational Inequality: Who Gets Retained in Macao and Why?

ERIC Educational Resources Information Center

Wong, Yi-Lee; Zhou, Yisu

2017-01-01

While the existence of a class, gender, or ethnic gap in educational attainment is well documented for many societies, how the practice of grade retention contributes to these patterns of educational inequality has been inadequately addressed. Given that grade retention is commonly practised in Macao, Macao is used as a case for illustration.…

Motivation: The Value of Developing Intrinsic Motivation in Elementary School Students in Grades Four through Six

ERIC Educational Resources Information Center

Gerstner, Gary M.

2017-01-01

This study sought to fill the gap in the literature concerning intrinsic motivation in elementary students in Grades 4-6 by examining 155 elementary school students and in-depth interviews with three elementary grade teachers. This study used data collected from the self-report survey called the Children's Academic Intrinsic Motivation Inventory…

New Concept Study for Repair of Bomb-Damaged Runways. Volume I. Concept Identification.

DTIC Science & Technology

1979-09-01

Expanded polystyrene beads would be pneumatically mixed with the cement to form a low density material. Initially, the ratio of foam to cement would...the combinations are presented with this concept. PRIMARY MATERIALS 0 Expanded polystyrene foam beads * Graded aggregate * Quick setting cement 61 E-4...probability of success - high ALTERNATE MATERIALS * Expanded polystyrene foam beads * Organic binders Furan Methyl Methacrylate Epoxy Aminos * Graded

Marginal adaptation of mineral trioxide aggregate (MTA) compared with amalgam as a root-end filling material: a low-vacuum (LV) versus high-vacuum (HV) SEM study.

PubMed

Shipper, G; Grossman, E S; Botha, A J; Cleaton-Jones, P E

2004-05-01

To compare the marginal adaptation of mineral trioxide aggregate (MTA) or amalgam root-end fillings in extracted teeth under low-vacuum (LV) versus high-vacuum (HV) scanning electron microscope (SEM) viewing conditions. Root-end fillings were placed in 20 extracted single-rooted maxillary teeth. Ten root ends were filled with MTA and the other 10 root ends were filled with amalgam. Two 1 mm thick transverse sections of each root-end filling were cut 0.50 mm (top) and 1.50 mm (bottom) from the apex. Gap size was recorded at eight fixed points along the dentine-filling material interface on each section when uncoated wet (LV wet (LVW)) and dry under LV (0.3 Torr) in a JEOL JSM-5800 SEM and backscatter emission (LV dry uncoated (LVDU)). The sections were then air-dried, gold-coated and gap size was recorded once again at the fixed points under HV (10(-6) Torr; HV dry coated (HVDC)). Specimen cracking, and the size and extent of the crack were noted. Gap sizes at fixed points were smallest under LVW and largest under HVDC SEM conditions. Gaps were smallest in MTA root-end fillings. A General Linear Models Analysis, with gap size as the dependent variable, showed significant effects for extent of crack in dentine, material and viewing condition (P = 0.0001). This study showed that MTA produced a superior marginal adaptation to amalgam, and that LVW conditions showed the lowest gap size. Gap size was influenced by the method of SEM viewing. If only HV SEM viewing conditions are used for MTA and amalgam root-end fillings, a correction factor of 3.5 and 2.2, respectively, may be used to enable relative comparisons of gap size to LVW conditions.

Gap formation following climatic events in spatially structured plant communities

PubMed Central

Liao, Jinbao; De Boeck, Hans J.; Li, Zhenqing; Nijs, Ivan

2015-01-01

Gaps play a crucial role in maintaining species diversity, yet how community structure and composition influence gap formation is still poorly understood. We apply a spatially structured community model to predict how species diversity and intraspecific aggregation shape gap patterns emerging after climatic events, based on species-specific mortality responses. In multispecies communities, average gap size and gap-size diversity increased rapidly with increasing mean mortality once a mortality threshold was exceeded, greatly promoting gap recolonization opportunity. This result was observed at all levels of species richness. Increasing interspecific difference likewise enhanced these metrics, which may promote not only diversity maintenance but also community invasibility, since more diverse niches for both local and exotic species are provided. The richness effects on gap size and gap-size diversity were positive, but only expressed when species were sufficiently different. Surprisingly, while intraspecific clumping strongly promoted gap-size diversity, it hardly influenced average gap size. Species evenness generally reduced gap metrics induced by climatic events, so the typical assumption of maximum evenness in many experiments and models may underestimate community diversity and invasibility. Overall, understanding the factors driving gap formation in spatially structured assemblages can help predict community secondary succession after climatic events. PMID:26114803

Solvent-Polarity-Induced Active Layer Morphology Control in Crystalline Diketopyrrolopyrrole-Based Low Band Gap Polymer Photovoltaics

NASA Astrophysics Data System (ADS)

Ferdous, Sunzida; Liu, Feng; Wang, Dong; Russell, Thomas

2014-03-01

The effects of various processing solvents on the morphology of diketopyrrolopyrrole (DPP)-based low band gap polymer (PDPPBT) and phenyl-C71-butyric acid methyl ester (PC71BM) blends are studied. The quality of the processing solvents was varied systematically using a mixture of a non-aromatic polar primary solvent with high boiling point secondary solvents of increasing polarities. An unfavorable solvent-PC71BM interaction affects the growth process of polymer crystallites inside the blend. When non-aromatic polar solvent was used, large PC71BM aggregates were formed that increase in size with the addition of non-polar secondary solvents. When polar solvents were instead used as the secondary solvents, the size scales of the aggregates decrease markedly, creating a percolated fibrillar network. Power conversion efficiencies of 0.03% to 5% are obtained, depending on the solvent system used.

Closing the Social Class Achievement Gap for First-Generation Students in Undergraduate Biology

PubMed Central

Harackiewicz, Judith M.; Canning, Elizabeth A.; Tibbetts, Yoi; Giffen, Cynthia J.; Blair, Seth S.; Rouse, Douglas I.; Hyde, Janet S.

2014-01-01

Many students start college intending to pursue a career in the biosciences, but too many abandon this goal because they struggle in introductory biology. Interventions have been developed to close achievement gaps for underrepresented minority students and women, but no prior research has attempted to close the gap for first-generation students, a population that accounts for nearly a fifth of college students. We report a values affirmation intervention conducted with 798 U.S. students (154 first-generation) in an introductory biology course for majors. For first-generation students, values affirmation significantly improved final course grades and retention in the second course in the biology sequence, as well as overall GPA for the semester. This brief intervention narrowed the achievement gap between first-generation and continuing generation students for course grades by 50% and increased retention in a critical gateway course by 20%. Our results suggest that educators can expand the pipeline for first-generation students to continue studying in the biosciences with psychological interventions. PMID:25049437

Chronic hemodynamic overload of the atria is an important factor for gap junction remodeling in human and rat hearts.

PubMed

Rucker-Martin, Catherine; Milliez, Paul; Tan, Sisareuth; Decrouy, Xavier; Recouvreur, Michel; Vranckx, Roger; Delcayre, Claude; Renaud, Jean-François; Dunia, Irene; Segretain, Dominique; Hatem, Stéphane N

2006-10-01

The expression and distribution of connexins is abnormal in a number of cardiac diseases, including atrial fibrillation, and is believed to favor conduction slowing and arrhythmia. Here, we studied the role of atrial structural remodeling in the disorganization of gap junctions and whether redistributed connexins can form new functional junction channels. Expression of connexin-43 (Cx43) was characterized by immunoblotting and immunohistochemistry in human right atrial specimens and in rat atria after myocardial infarction (MI). Gap junctions were studied by electron and 3-D microscopy, and myocyte-myocyte coupling was determined by Lucifer yellow dye transfer. In both chronically hemodynamically overloaded human atria in sinus rhythm and in dilated atria from MI-rats, Cx43 were dephosphorylated and redistributed from the intercalated disc to the lateral cell membranes as observed during atrial fibrillation. In MI-rats, the gap junctions at the intercalated disc were smaller (20% decrease) and contained very little Cx43 (0 or 1 gold particle vs. 42 to 98 in sham-operated rats). In the lateral membranes of myocytes, numerous connexon aggregates comprising non-phosphorylated Cx43 were observed. These connexon aggregates were in no case assembled into gap junction plaque-like structures. However, N-cadherin was well organized in the intercalated disc. There was very little myocyte-myocyte coupling in MI-rat atria and no myocyte-fibroblast coupling. Regression of the atrial remodeling was associated with the normalization of Cx43 localization. Structural alteration of the atrial myocardium is an important factor in the disorganization of connexins and gap junction. Moreover, redistributed Cx43 do not form junction channels.

A theoretical study of heterojunction and graded band gap type solar cells

NASA Technical Reports Server (NTRS)

Chiang, J. P. C.; Hauser, J. R.

1979-01-01

The work performed concentrated on including multisun effects, high temperature effects, and electron irradiation effects into the computer analysis program for heterojunction and graded bandgap solar cells. These objectives were accomplished and the program is now available for such calculations.

Optically initiated silicon carbide high voltage switch

DOEpatents

Caporaso, George J [Livermore, CA; Sampayan, Stephen E [Manteca, CA; Sullivan, James S [Livermore, CA; Sanders,; David, M [Livermore, CA

2011-02-22

An improved photoconductive switch having a SiC or other wide band gap substrate material, such as GaAs and field-grading liners composed of preferably SiN formed on the substrate adjacent the electrode perimeters or adjacent the substrate perimeters for grading the electric fields.

Divergent Streams: Race-Gender Achievement Gaps at Selective Colleges and Universities.

PubMed

Massey, Douglas S; Probasco, Lierin

2010-03-01

In this paper, we extend previous research on racial performance gaps at 28 selective US colleges and universities by examining differences in grade achievement and graduate rates across race-gender categories. Using data from the National Longitudinal Survey of Freshmen, we show that black males, black females, and Hispanic males attain significantly lower grades than other race-gender groups, and that black males are 35% less likely to graduate on-time than other race-gender groups. Analyses consider an array of personal and institutional indicators of academic performance. Grades and graduation rates are improved by academic preparation (particularly high school GPA), scholarly effort, and, for graduation rates, membership in career-oriented or majority-white campus groups. Grade performance and graduation rates are undermined by a hostile racial climate on campus, family stress, and stereotype threat, all of which disproportionately affect minority students. We conclude with recommendations to college administrators for ways of selecting and supporting minority students to reduce differentials in academic achievement across race-gender groups.

A study on the performance of concrete containing recycled aggregates and ceramic as materials replacement

NASA Astrophysics Data System (ADS)

Azmi, N. B.; Khalid, F. S.; Irwan, J. M.; Anting, N.; Mazenan, P. N.

2017-11-01

Natural fine aggregate materials are commonly used in development and commercial construction in Malaysia. In fact, concrete production was increased as linear with the growing Malaysia economy. However, an issue was production of concrete was to locate adequate sources of natural fine aggregates. There lot of studies have been conducted in order to replace the fine aggregate in which natural fine aggregate replace with the waste material in concrete preparation. Therefore, this study aims to utilize the Recycled Concrete Aggregate (RCA) and ceramic waste which has great potential to replace the natural aggregate in concrete mix with different type of method, admixture, and parameters. This research were focused on compressive strength and water absorption test to determine the optimum mix ratio of concrete mix. The concrete aggregate was chosen due to improvement capillary bonding mechanisms and ceramic presented similar strength compared to the conventional concrete using natural aggregate. Percent of replacement have been used in this study was at 25%, 35% and 45% of the RCA and 5%, 10% and 15% for ceramic, respectively. Furthermore, this research was conduct to find the optimum percentage of aggregate replacement, using water-cement ratio of 0.55 with concrete grade 25/30. The best percentage of replacement was the RCA35% C15% with the compressive strength of 34.72 MPa and the water absorption was satisfied.

Closing Achievement Gaps with a Utility-Value Intervention: Disentangling Race and Social Class

PubMed Central

Harackiewicz, Judith M.; Canning, Elizabeth A.; Tibbetts, Yoi; Priniski, Stacy J.; Hyde, Janet S.

2015-01-01

Many college students abandon their goal of completing a degree in STEM when confronted with challenging introductory-level science courses. In the U.S., this trend is more pronounced for underrepresented minority (URM) and first-generation (FG) students, and contributes to persisting racial and social-class achievement gaps in higher education. Previous intervention studies have focused exclusively on race or social class, but have not examined how the two may be confounded and interact. This research therefore investigates the independent and interactive effects of race and social class as moderators of an intervention designed to promote performance, measured by grade in the course. In a double-blind randomized experiment conducted over four semesters of an introductory biology course (N = 1040), we tested the effectiveness of a utility-value intervention in which students wrote about the personal relevance of course material. The utility-value intervention was successful in reducing the achievement gap for FG-URM students by 61%: the performance gap for FG-URM students, relative to CG-Majority students, was large in the control condition, .84 grade points (d = .98), and the treatment effect for FG-URM students was .51 grade points (d = 0.55). The UV intervention helped students from all groups find utility value in the course content, and mediation analyses showed that the process of writing about utility value was particularly powerful for FG-URM students. Results highlight the importance of examining the independent and interactive effects of race and social class when evaluating interventions to close achievement gaps and the mechanisms through which they may operate. PMID:26524001

Design and evaluation of foamed asphalt base materials.

DOT National Transportation Integrated Search

2013-05-01

Foamed asphalt stabilized base (FASB) combines reclaimed asphalt pavement (RAP), recycled : concrete (RC), and/or graded aggregate base (GAB) with a foamed asphalt binder to produce a : partially stabilized base material. The objectives of this study...

Design and evaluation of foamed asphalt base materials : [research summary].

DOT National Transportation Integrated Search

2013-05-01

Foamed asphalt stabilized base (FASB) combines reclaimed asphalt pavement (RAP), : recycled concrete (RC), and/or graded aggregate base (GAB) with a foamed asphalt : binder to produce a partially stabilized base material. Although widely used, most :...

Recycled blocks with improved sound and fire insulation containing construction and demolition waste.

PubMed

Leiva, Carlos; Solís-Guzmán, Jaime; Marrero, Madelyn; García Arenas, Celia

2013-03-01

The environmental problem posed by construction and demolition waste (C&D waste) is derived not only from the high volume produced, but also from its treatment and disposal. Treatment plants receive C&D waste which is then transformed into a recycled mixed aggregate. The byproduct is mainly used for low-value-added applications such as land escape restoration, despite the high quality of the aggregate. In the present work, the chemical composition properties and grading curve properties of these aggregates are defined. Furthermore, the resulting recycled concrete with a high proportion of recycled composition, from 20% to 100% replacement of fine and coarse aggregate, is characterized physically and mechanically. An environmental study of the new construction material when all aggregates are substituted by C&D waste shows a low toxicity level, similar to that of other construction materials. The new material also has improved properties with respect to standard concrete such as high fire resistance, good heat insulation, and acoustic insulation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Using Real-Time Data and Corrective Teacher-Feedback as a Mechanism to Improve Children's Reading Skills: An Exploratory Study in the Millennium Village Site of Bonsaaso, Ghana

ERIC Educational Resources Information Center

Iyengar, Radhika; Muffly, Sarah; Akomaning-Mensah, Charles; Karim, Alia; Pokharel, Prabhas; Adeni, Sarayu

2016-01-01

Educational outcomes across multiple countries show large gaps between children's grade level curricular expectations and the actual learning levels of children. This paper discusses findings from an early grades literacy study and attempts to explore factors that potentially improve the English language learning results of Grades 3 and 4 learners…

The Effects of Teachers' Gender-Stereotypical Expectations on the Development of the Math Gender Gap

ERIC Educational Resources Information Center

Robinson, Joseph P.; Lubienski, Sarah T.; Copur, Yasemin

2011-01-01

Scholars have identified mathematics gender gaps favoring males as early as kindergarten or first grade, particularly at the top of the achievement distribution (Penner & Paret, 2008; Rathbun, West & Germino-Hausken, 2004; Robinson & Lubienski, 2011). These relatively small achievement disparities precede larger differences in…

Gender Gap Linked to Differential Socialization for High-Achieving Senior Mathematics Students.

ERIC Educational Resources Information Center

Campbell, James R.; Beaudry, Jeffrey S.

1998-01-01

Examined whether 11th-grade girls and boys enrolled in advanced mathematics courses nationwide were socialized in similar ways, using Campbell's differential socialization paradigm. Results uncovered a gender gap favoring boys. Self-imposed pressure and persistence had important direct effects on achievement. Self-concept had important direct…

Making the Grade

ERIC Educational Resources Information Center

Stewart, Pearl

2012-01-01

At San Diego State University, retention and graduation rates garner national attention. The author discusses SDSU's intensive efforts to improve its graduation and retention rates and to close the achievement gap. San Diego State has been lauded nationally for its success on closing the achievement gap. An article titled "Walking the Walk on…

TERT promoter mutation and its interaction with IDH mutations in glioma: Combined TERT promoter and IDH mutations stratifies lower-grade glioma into distinct survival subgroups-A meta-analysis of aggregate data.

PubMed

Vuong, Huy Gia; Altibi, Ahmed M A; Duong, Uyen N P; Ngo, Hanh T T; Pham, Thong Quang; Chan, Aden Ka-Yin; Park, Chul-Kee; Fung, Kar-Ming; Hassell, Lewis

2017-12-01

The clinical significance of telomerase reverse transcriptase (TERT) promoter mutation in glioma remains unclear. The aim of our meta-analysis is to investigate the prognostic impact TERT promoter mutation in glioma patients and its interaction with other molecular markers, particularly Isocitrate Dehydrogenase (IDH) mutation from aggregate level data. Relevant articles were searched in four electronic databases including PubMed, Scopus, Web of Science and Virtual Health Library. Pooled HRs were calculated using random effect model weighted by inverse variance method. From 1010 studies, we finally included 28 studies with 11519 patients for meta-analyses. TERT mutation is significantly associated with compromised overall survival (OS) (HR=1.38; 95% CI=1.15-1.67) and progression-free survival (PFS) (HR=1.31; 95% CI=1.06-1.63) in glioma patients. In studying its reaction with IDH, TERT promoter mutation was associated with reduced OS in both IDH-mutant (IDH-mut) and IDH-wild type (IDH-wt) glioblastomas but shown to have inverse effects on IDH-mut and IDH-wt grade II/III tumors. Our analysis categorized WHO grade II/III glioma patients into four distinct survival subgroups with descending survival as follow: TERT-mut/IDH-mut≫TERT-wt/IDH-mut≫TERT-wt/IDH-wt≫TERT-mut/IDH-wt. Prognostic value of TERT promoter mutations in gliomas is dependent on tumor grade and the IDH mutational status. With the same tumor grade in WHO grade II and III tumors and the same IDH mutation status, TERT-mut is a prognostic factor. Copyright © 2017 Elsevier B.V. All rights reserved.

Examining Multidimensional Middle Grade Outcomes after Early Elementary School Grade Retention

ERIC Educational Resources Information Center

Hwang, Sophia; Cappella, Elise; Schwartz, Kate

2016-01-01

Recently, researchers have begun to employ rigorous statistical methods and developmentally-informed theories to evaluate outcomes for students retained in non-kindergarten early elementary school. However, the majority of this research focuses on academic outcomes. Gaps remain regarding retention's effects on psychosocial outcomes important to…

Characterization of reaction intermediate aggregates in aniline oxidative polymerization at low proton concentration.

PubMed

Ding, Zhongfen; Sanchez, Timothy; Labouriau, Andrea; Iyer, Srinivas; Larson, Toti; Currier, Robert; Zhao, Yusheng; Yang, Dali

2010-08-19

Aggregates of reaction intermediates form during the early stages of aniline oxidative polymerization whenever the initial mole ratio of proton concentration to aniline monomer concentration is low ([H(+)](0)/[An](0)

Bead-Level Characterization of Early-Stage Amyloid β42 Aggregates: Nuclei and Ionic Concentration Effects.

PubMed

Hu, Dingkun; Zhao, Wei; Zhu, Yong; Ai, Hongqi; Kang, Baotao

2017-11-16

A growing body of evidence shows that soluble β-amyloid (Aβ) aggregates, oligomers, and even protofibrils, may be more neurotoxic than fibrils. Here, we employ a coarse grain model to investigate the aggregation of 75mer Aβ 42 oligomers and the salt effect, the cornerstone of fibril evolution. We find that the oligomer morphologies generated by seventy-five monomers or mixed by both fifty monomers and five preset pentameric nuclei are different (spherical vs. bar-/disk-shaped) and are characterize by a full of coil content (former) and >70 % β-turn content (latter), indicating a novel role of the nuclei played in the early aggregation stage. The aggregation for the former oligomer adopts a master-nucleus mechanism, whereas for the latter combination of monomers and pentamers a multi-nuclei one is found. The random salt ions will distribute around the aggregates to form several ion shells as the aggregation develops. A unique two-fold gap between the shells is observed in the system containing 100 mm NaCl, endowing the physiological salt concentration with special implications. Meanwhile, an accurate ion-solute cutoff distance (0.66 nm) is predicted, and recommended to apply to many other aggregated biomolecular systems. The present distribution scenario of ions can be generalized to other aggregated systems, although it is strictly dependent on the identity of a specific aggregate, such as its charge and composition. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chip seal design and specifications : final report.

DOT National Transportation Integrated Search

2016-12-01

Chip seals or seal coats, are a pavement preservation method constructed using a layer of asphalt binder that is covered by a uniformly graded aggregate. The benefits of chip seal include: sealing surface cracks, keeping water from penetrating the su...

Laboratory evaluation of Trinidad Lake Asphalt : final report.

DOT National Transportation Integrated Search

1985-05-01

The Department has examined several asphalt cement additives over the last 6 - 8 years in an attempt to produce an increased strength dense graded asphaltic concrete or an acceptable mix using marginal sand aggregates. Trinidad Lake Asphalt, an natur...

Sexually Transmitted Infections and First Sexual Intercourse Age in Adolescents: The Nationwide Retrospective Cross-Sectional Study.

PubMed

Lee, Seo Yoon; Lee, Hyo Jung; Kim, Tae Kyoung; Lee, Sang Gyu; Park, Eun-Cheol

2015-12-01

Sexually transmitted infections (STIs) are major causes of medical and psychological problems globally, while adolescents in South Korea have recently shown rapid changes in sexual behaviors. We aimed to examine the association between the age of first sexual intercourse and the experience of STIs among adolescents. Additionally, in which specific time period would more likely to get infected from sexual intercourse. We used data from the 2007-2013 Korea Youth Risk Behavior Web-based Survey. Only adolescents with sexual intercourse experience (N = 22,381) were included, and multiple logistic regression analysis was performed. One dichotomized measure and one continuous measure were assessed: (i) STIs experience (defined as having had STIs); and (ii) association between STIs experience and absolute age gap (defined as temporal differences between secondary sexual character emergence age and first sexual intercourse age). Approximately 7.4% of boys and 7.5% of girls reported had STI. For both boys and girls, the chance of experiencing STIs increased as the age of first sexual intercourse decreased (boys: before elementary school [age 7 or under]: odds ratio [OR] = 10.81, first grade [age 7 or 8]: OR = 4.44, second grade [age 8 or 9]: OR = 8.90, fourth grade [age 10 or 11]: OR = 7.20, ninth grade [age 15 or 16]: OR = 2.31; girls: before elementary school: OR = 18.09, first grade: OR = 7.26, second grade: OR = 7.12, fourth grade: OR = 8.93, ninth grade: OR = 2.74). The association between the absolute age gap and STI experience was examined additionally (boys: OR = 0.93, girls: OR = 0.87). This study shows that earlier initiation of sexual intercourse increases the odds of experiencing STIs. Also as the age gap gets shorter, the odds of experiencing STIs increase. Our study suggests that it is important to consider the time period of first sexual intercourse and to reinforce a monitoring system along with the development of other preventive strategies. © 2015 International Society for Sexual Medicine.

A Capstone Project Using the Gap Analysis Model: Closing the College Readiness Gap for Latino English Language Learners with a Focus on College Affordability and Student Grades

ERIC Educational Resources Information Center

Kurland, Michael A. T.

2013-01-01

This capstone dissertation inquiry project focused on the underperformance of English language learners (ELLs) at a high school. The Clark and Estes' (2008) gap analysis model was the analytical framework used to conduct this inquiry. At the request of the school, the inquiry focus was on gaining a better understanding of the underachievement…

Aggregation of estimated numbers of undiscovered deposits: an R-script with an example from the Chu Sarysu Basin, Kazakhtan: Chapter B in Global mineral resource assessment

USGS Publications Warehouse

Schuenemeyer, John H.; Zientek, Michael L.; Box, Stephen E.

2011-01-01

Mineral resource assessments completed by the U.S. Geological Survey during the past three decades express geologically based estimates of numbers of undiscovered mineral deposits as probability distributions. Numbers of undiscovered deposits of a given type are estimated in geologically defined regions. Using Monte Carlo simulations, these undiscovered deposit estimates are combined with tonnage and grade models to derive a probability distribution describing amounts of commodities and rock that could be present in undiscovered deposits within a study area. In some situations, it is desirable to aggregate the assessment results from several study areas. This report provides a script developed in open-source statistical software, R, that aggregates undiscovered deposit estimates of a given type, assuming independence, total dependence, or some degree of correlation among aggregated areas, given a user-specified correlation matrix.

Potential applicability of stress wave velocity method on pavement base materials as a non-destructive testing technique

NASA Astrophysics Data System (ADS)

Mahedi, Masrur

Aggregates derived from natural sources have been used traditionally as the pavement base materials. But in recent times, the extraction of these natural aggregates has become more labor intensive and costly due to resource depletion and environmental concerns. Thus, the uses of recycled aggregates as the supplementary of natural aggregates are increasing considerably in pavement construction. Use of recycled aggregates such as recycled crushed concrete (RCA) and recycled asphalt pavement (RAP) reduces the rate of natural resource depletion, construction debris and cost. Although recycled aggregates could be used as a viable alternative of conventional base materials, strength characteristics and product variability limit their utility to a great extent. Hence, their applicability is needed to be evaluated extensively based on strength, stiffness and cost factors. But for extensive evaluation, traditionally practiced test methods are proven to be unreasonable in terms of time, cost, reliability and applicability. On the other hand, rapid non-destructive methods have the potential to be less time consuming and inexpensive along with the low variability of test results; therefore improving the reliability of estimated performance of the pavement. In this research work, the experimental program was designed to assess the potential application of stress wave velocity method as a non-destructive test in evaluating recycled base materials. Different combinations of cement treated recycled concrete aggregate (RAP) and recycled crushed concrete (RCA) were used to evaluate the applicability of stress wave velocity method. It was found that, stress wave velocity method is excellent in characterizing the strength and stiffness properties of cement treated base materials. Statistical models, based on P-wave velocity were derived for predicting the modulus of elasticity and compressive strength of different combinations of cement treated RAP, Grade-1 and Grade-2 materials. Two, three and four parameter modeling were also done for characterizing the resilient modulus response. It is anticipated that, derived correlations can be useful in estimating the strength and stiffness response of cement treated base materials with satisfactory level of confidence, if the P-wave velocity remains within the range of 500 ft/sec to 1500 ft/sec.

Barrier infrared detector

NASA Technical Reports Server (NTRS)

Ting, David Z. (Inventor); Khoshakhlagh, Arezou (Inventor); Soibel, Alexander (Inventor); Hill, Cory J. (Inventor); Gunapala, Sarath D. (Inventor)

2012-01-01

A superlattice-based infrared absorber and the matching electron-blocking and hole-blocking unipolar barriers, absorbers and barriers with graded band gaps, high-performance infrared detectors, and methods of manufacturing such devices are provided herein. The infrared absorber material is made from a superlattice (periodic structure) where each period consists of two or more layers of InAs, InSb, InSbAs, or InGaAs. The layer widths and alloy compositions are chosen to yield the desired energy band gap, absorption strength, and strain balance for the particular application. Furthermore, the periodicity of the superlattice can be "chirped" (varied) to create a material with a graded or varying energy band gap. The superlattice based barrier infrared detectors described and demonstrated herein have spectral ranges covering the entire 3-5 micron atmospheric transmission window, excellent dark current characteristics operating at least 150K, high yield, and have the potential for high-operability, high-uniformity focal plane arrays.

Perioperative analgesia for patients undergoing endoscopic sinus surgery: an evidence-based review.

PubMed

Svider, Peter F; Nguyen, Brandon; Yuhan, Brian; Zuliani, Giancarlo; Eloy, Jean Anderson; Folbe, Adam J

2018-04-12

Misuse and diversion of prescription opioids have been critical in facilitating the opioid epidemic. Our objective was to perform a systematic evidence-based review delineating perioperative regimens (including opioid alternatives) evaluated for endoscopic sinus surgery. PubMed/MEDLINE, Cochrane Library, and EmBase databases were evaluated for studies detailing analgesics employed after endoscopic sinus surgery. Studies were assessed for level of evidence. Bias risk was evaluated using the Cochrane Bias tool and GRADE criteria. Medication, administration, adverse effects, pain scores, and rescue analgesic consumption were evaluated. A summary of evidence detailing benefits, harm, and cost was prepared. Thirty-two studies encompassing 1812 patients were included. The GRADE criteria determined the overall evidence to be of moderate quality. Perioperative acetaminophen had few adverse events and reduced immediate need for opioid rescue after sinus surgery; studies evaluating acetaminophen demonstrate a preponderance of benefit over harm. Nonsteroidal anti-inflammatory drugs (NSAIDs) also reduce postoperative opioid consumption, although a small portion of patients undergoing sinus surgery harbor the potential for NSAID intolerance. The aggregate level of evidence for studies evaluating NSAIDs was grade A, whereas the aggregate grade of evidence for several other agents was grade B. There is evidence supporting the use of NSAIDs and gabapentin for the control of pain after endoscopic sinus surgery. Acetaminophen, α-agonists, and local anesthetics are also viable options for postoperative analgesia. Familiarity with these data is essential to facilitate the use of opioid alternatives. Further large-scale, multi-institutional, randomized trials are needed to provide conclusive recommendations for these perioperative analgesics. © 2018 ARS-AAOA, LLC.

Minority Achievement Gaps in STEM: Findings of a Longitudinal Study of Project Excite

ERIC Educational Resources Information Center

Olszewski-Kubilius, Paula; Steenbergen-Hu, Saiying; Thomson, Dana; Rosen, Rhoda

2017-01-01

This longitudinal study examined the outcomes of Project Excite on reducing minority students' achievement gaps in STEM over 14 years. Project Excite was designed to provide intensive supplemental enrichment and accelerated programming for high-potential, underrepresented minority students from third through eighth grades to better prepare them…

Racial and Gender Gaps in Academic Achievement. Report Summary.

ERIC Educational Resources Information Center

Dulaney, Chuck; Banks, Karen

This report summarizes the level of academic achievement, and the extent of racial and gender gaps in that achievement, of students in North Carolina's Wake County Public School System (WCPSS). The comparison was conducted using 1993 End-of-Grade (EOG) tests; low income group EOG test performance; 1993 writing tests and high school writing…

Bridging English Language Learner Achievement Gaps through Effective Vocabulary Development Strategies

ERIC Educational Resources Information Center

Gibson, Charles

2016-01-01

Despite a well-documented history of immigration in the United States of America and rise in population of students that speak a language other than English, academic achievement gaps between English Language Learners and their native English language speaking counterparts from Grades Pre-Kindergarten through the college/university level still…

Equal Knowledge Is the Strong Root of Democratic Egalitarianism

ERIC Educational Resources Information Center

Palumbo, Anthony; Levitt, Roberta

2011-01-01

This article considers how to bridge the achievement gap by showing that reading methodology influenced American educational philosophy, primary-grade curricula, and American schools. It considers the impact of the romantic movement on progressive education and notes that the current academic achievement gap has two roots. The first can be traced,…

Subgroup Achievement and Gap Trends: New Hampshire

ERIC Educational Resources Information Center

Center on Education Policy, 2009

2009-01-01

This year the Center on Education Policy analyzed data on the achievement of different groups of students in two distinct ways. First, it looked at grade 4 test results to determine whether the performance of various groups improved at three achievement levels--basic and above, proficient and above, and advanced. Second, it looked at gaps between…

Understanding Science Achievement Gaps by Race/Ethnicity and Gender in Kindergarten and First Grade

ERIC Educational Resources Information Center

Curran, F. Chris; Kellogg, Ann T.

2016-01-01

Disparities in science achievement across race and gender have been well documented in secondary and postsecondary school; however, the science achievement gap in the early years of elementary school remains understudied. We present findings from the recently released Early Childhood Longitudinal Study, Kindergarten Class of 2010-2011 that…

Rural-Urban Gaps in Academic Achievement, Schooling Conditions, Student, and Teachers' Characteristics in Pakistan

ERIC Educational Resources Information Center

Tayyaba, Saadia

2012-01-01

Purpose: Recent educational research has demonstrated rural-urban gaps in achievement and schooling conditions. Evidence from developing countries is still sparse. This study seeks to report rural-urban disparities in achievement, student, teacher, and school characteristics based on a nationally representative sample of grade four students from…

A cost-comparison methodology for selecting appropriate hot-mix asphalt materials.

DOT National Transportation Integrated Search

2007-01-01

The Virginia Department of Transportation's (VDOT) Road and Bridge Specifications lists 9 dense-graded hot-mix asphalt (HMA) surface mixes (three aggregate gradations x three binder types) that could be used on Virginia's highways. VDOT's Special Pro...

Closing achievement gaps with a utility-value intervention: Disentangling race and social class.

PubMed

Harackiewicz, Judith M; Canning, Elizabeth A; Tibbetts, Yoi; Priniski, Stacy J; Hyde, Janet S

2016-11-01

Many college students abandon their goal of completing a degree in science, technology, engineering, or math (STEM) when confronted with challenging introductory-level science courses. In the U.S., this trend is more pronounced for underrepresented minority (URM) and first-generation (FG) students, and contributes to persisting racial and social-class achievement gaps in higher education. Previous intervention studies have focused exclusively on race or social class, but have not examined how the 2 may be confounded and interact. This research therefore investigates the independent and interactive effects of race and social class as moderators of an intervention designed to promote performance, measured by grade in the course. In a double-blind randomized experiment conducted over 4 semesters of an introductory biology course (N = 1,040), we tested the effectiveness of a utility-value intervention in which students wrote about the personal relevance of course material. The utility-value intervention was successful in reducing the achievement gap for FG-URM students by 61%: the performance gap for FG-URM students, relative to continuing generation (CG)-Majority students, was large in the control condition, .84 grade points (d = .98), and the treatment effect for FG-URM students was .51 grade points (d = 0.55). The UV intervention helped students from all groups find utility value in the course content, and mediation analyses showed that the process of writing about utility value was particularly powerful for FG-URM students. Results highlight the importance of intersectionality in examining the independent and interactive effects of race and social class when evaluating interventions to close achievement gaps and the mechanisms through which they may operate. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Indigenous Students' Increasing Risk of Grade Repetition in Early Schooling

ERIC Educational Resources Information Center

Anderson, Robyn

2012-01-01

The current study considers grade repetition rates in the early years of school, Preparatory (Prep) to Year 3, in Queensland state schools, of which there is a significant gap in the Australian research literature. Data accessed from the Queensland Government's Department of Education and Training (DET), shows that particular groups of students…

Defining the optimal method for reporting prostate cancer grade and tumor extent on magnetic resonance/ultrasound fusion-targeted biopsies.

PubMed

Gordetsky, Jennifer B; Schultz, Luciana; Porter, Kristin K; Nix, Jeffrey W; Thomas, John V; Del Carmen Rodriguez Pena, Maria; Rais-Bahrami, Soroush

2018-06-01

Magnetic resonance (MR)/ultrasound fusion-targeted biopsy (TB) routinely samples multiple cores from each MR lesion of interest. Pathologists can evaluate the extent of cancer involvement and grade using an individual core (IC) or aggregate (AG) method, which could potentially lead to differences in reporting. We reviewed patients who underwent TB followed by radical prostatectomy (RP). TB cores were evaluated for grade and tumor extent by 2 methods. In the IC method, the grade for each TB lesion was based on the core with the highest Gleason score. Tumor extent for each TB was based on the core with the highest percent of tumor involvement. In the AG method, the tumor from all cores within each TB lesion was aggregated to determine the final composite grade and percentage of tumor involvement. Each method was compared with MR lesional volume, MR lesional density (lesion volume/prostate volume), and RP. Fifty-five patients underwent TB followed by RP. Extent of tumor by the AG method showed a better correlation with target lesion volume (r= 0.27,P= .022) and lesional density (r = 0.32, P = .008) than did the IC method (r= 0.19 [P = .103] andr= 0.22 [P = .062]), respectively. Extent of tumor on TB was associated with extraprostatic extension on RP by the AG method (P= .04), but not by the IC method. This association was significantly higher in patients with a grade group (GG) of 3 or higher (P= .03). A change in cancer grade occurred in 3 patients when comparing methods (2 downgraded GG3 to GG2, 1 downgraded GG4 to GG3 by the AG method). For multiple cores obtained via TB, the AG method better correlates with target lesion volume, lesional density, and extraprostatic extension. Copyright © 2018 Elsevier Inc. All rights reserved.

Reduced recombination in a surface-sulfurized Cu(InGa)Se2 thin-film solar cell

NASA Astrophysics Data System (ADS)

Kim, Shinho; Nishinaga, Jiro; Kamikawa, Yukiko; Ishizuka, Shogo; Nagai, Takehiko; Koida, Takashi; Tampo, Hitoshi; Shibata, Hajime; Matsubara, Koji; Niki, Shigeru

2018-05-01

This study demonstrates surface sulfurization effects on Cu(InGa)Se2 (CIGSe) thin-film solar cells with a single back-graded band gap. Single back-graded CIGSe thin films were prepared via a three-stage process in a high-vacuum molecular beam epitaxial growth chamber and were subsequently annealed in a tube furnace under environmental conditions with H2S gas. After sulfurization, an ∼80- to ∼100-nm-thick CuIn(SSe)2 layer with significantly small Ga contents (CISSe:Ga) was formed on the CIGSe layer. The newly formed CISSe:Ga layer exhibited graded S contents from surface to bulk, thus resulting in a front-graded band gap. In addition, CISSe:Ga was covered with S-enriched CISSe region that was extended from the surface to a depth of a few nm and was depleted of Ga. A device with the sulfurized CIGSe showed reduced recombination at the buffer–absorber interface, in space-charge region and in bulk. Consequently, the open circuit voltage increased from 0.58 V (in the non-sulfurized case) to 0.66 V, and the conversion efficiency improved from 15.5 to 19.4%. This large improvement is caused by the front graded band gap at the surface and the hole-blocking barrier, which suppress recombination at the CdS/CISSe:Ga interface. In addition, sulfurization followed by KF post-deposition treatment (PDT) increased the efficiency to 20.1%. Compared to the untreated sulfurized device, the KF-PDT device delivered an increased carrier lifetime and reduced the recombination in bulk probably because the defects were passivated by the K, which penetrated into the bulk region.

Predictors and Outcomes of Early vs. Later English Language Proficiency Among English Language Learners

PubMed Central

Halle, Tamara; Hair, Elizabeth; Wandner, Laura; McNamara, Michelle; Chien, Nina

2011-01-01

The development of English language learners (ELLs) was explored from kindergarten through eighth grade within a nationally representative sample of first-time kindergartners (N = 19,890). Growth curve analyses indicated that, compared to native English speakers, ELLs were rated by teachers more favorably on approaches to learning, self control, and externalizing behaviors in kindergarten and generally continued to grow in a positive direction on these social/behavioral outcomes at a steeper rate compared to their native English-speaking peers, holding other factors constant. Differences in reading and math achievement between ELLs and native English speakers varied based on the grade at which English proficiency is attained. Specifically, ELLs who were proficient in English by kindergarten entry kept pace with native English speakers in both reading and math initially and over time; ELLs who were proficient by first grade had modest gaps in reading and math achievement compared to native English speakers that closed narrowly or persisted over time; and ELLs who were not proficient by first grade had the largest initial gaps in reading and math achievement compared to native speakers but the gap narrowed over time in reading and grew over time in math. Among those whose home language is not English, acquiring English proficiency by kindergarten entry was associated with better cognitive and behavioral outcomes through eighth grade compared to taking longer to achieve proficiency. Multinomial regression analyses indicated that child, family, and school characteristics predict achieving English proficiency by kindergarten entry compared to achieving proficiency later. Results are discussed in terms of policies and practices that can support ELL children’s growth and development. PMID:22389551

Effect of Blood Contamination on Marginal Adaptation and Surface Microstructure of Mineral Trioxide Aggregate: A SEM Study.

PubMed

Salem Milani, Amin; Rahimi, Saeed; Froughreyhani, Mohammad; Vahid Pakdel, Mahdi

2013-01-01

In various clinical situations, mineral trioxide aggregate (MTA) may come into direct contact or even be mixed with blood. The aim of the present study was to evaluate the effect of exposure to blood on marginal adaptation and surface microstructure of MTA. Thirty extracted human single-rooted teeth were used. Standard root canal treatment was carried out. Root-ends were resected, and retrocavities were prepared. The teeth were randomly divided into two groups (n = 15): in group 1, the internal surface of the cavities was coated with fresh blood. Then, the cavities were filled with MTA. The roots were immersed in molds containing fresh blood. In group 2, the aforementioned procedures were performed except that synthetic tissue fluid (STF) was used instead of blood. To assess the marginal adaptation, "gap perimeter" and "maximum gap width" were measured under scanning electron microscope. The surface microstructure was also examined. Independent samples t-test and Mann-Whitney U test were used to analyze the data. Maximum gap width and gap perimeter in the blood-exposed group were significantly larger than those in the STF-exposed group (p < 0.01). In the blood-exposed group, the crystals tended to be more rounded and less angular compared with the STF-exposed group, and there was a general lack of needle-like crystals. Exposure to blood during setting has a negative effect on marginal adaptation of MTA, and blood-exposed MTA has a different surface microstructure compared to STF-exposed MTA.

Aggregate mixture found to increase safety on roads : fact sheet.

DOT National Transportation Integrated Search

2011-11-01

Constructing a safe and durable highway system in Louisiana has long been a major concern for highway engineers. Open-graded friction course (OGFC) mixtures have shown to improve wet weather visibility, which can be a leading factor in causing wet we...

Evaluation of mix designs and test procedures for pervious concrete.

DOT National Transportation Integrated Search

2014-10-01

Pervious concrete is mixture of cement, aggregate, and water that provide a level of porosity which allows : water to percolate into the sub-grade. It differs from the conventional concrete since it usually contains a : smaller amount of fine aggrega...

Comparative Evaluation of Marginal Adaptation of BiodentineTM and Other Commonly Used Root End Filling Materials-An Invitro Study

PubMed Central

P.V., Ravichandra; Vemisetty, Harikumar; K., Deepthi; Reddy S, Jayaprada; D., Ramkiran; Krishna M., Jaya Nagendra; Malathi, Gita

2014-01-01

Aim: The purpose of this investigation was to evaluate the marginal adaptation of three root-end filling materials Glass ionomer cement, Mineral trioxide aggregate and BiodentineTM. Methodology: Thirty human single-rooted teeth were resected 3 mm from the apex. Root-end cavities were then prepared using an ultrasonic tip and filled with one of the following materials Glass ionomer cement (GIC), Mineral trioxide aggregate (MTA) and a bioactive cement BiodentineTM. The apical portions of the roots were then sectioned to obtain three 1 mm thick transversal sections. Confocal laser scanning microscopy (CLSM) was used to determine area of gaps and adaptation of the root-end filling materials with the dentin. The Post hoc test, a multiple comparison test was used for statistical data analysis. Results: Statistical analysis showed lowest marginal gaps (11143.42±967.753m2) and good marginal adaptation with BiodentineTM followed by MTA (22300.97±3068.883m2) and highest marginal gaps with GIC (33388.17±12155.903m2) which were statistically significant (p<0.0001). Conclusion: A new root end filling material BiodentineTM showed better marginal adaptation than commonly used root end filling materials PMID:24783148

Understanding the Gender Gap in Introductory Physics

NASA Astrophysics Data System (ADS)

Finkelstein, Noah; Kost, Lauren; Pollock, Steven

2008-04-01

While it has been suggested interactive engagement (IE) techniques can eliminate the gender gap (the difference in performance between men and women on measures of conceptual learning), we find that, at our institution, the gender gap persisted from pre to posttest in IE classes (Pollock, Physical Review: ST PER. 3, 010107, 2007). This talk reports on a three-part follow-up study that investigates what factors contribute to the gender gap. First, we analyze student grades in different components of the course and find that men and women's course grades are not significantly different (p>0.1), but men outscore women on exams and women outscore men on homework and participation. Second, we compare average posttest scores of men and women who score similarly on the pretest and find that there are no significant differences between men and women's average posttest scores. Finally, we analyze other factors in addition to the pretest score that could influence the posttest score and find that gender does not account for a majorportion of the variation in posttest scores when a measure of mathematics performance is included. These findings indicate that the gender gap exists in interactive physics classes, but may be due in large part to differences in preparation, background, and math skills as assessed by traditional survey instruments.

The role of occupational attributes in gender earnings inequality, 1970-2010.

PubMed

Mandel, Hadas

2016-01-01

Grounded in the research on the important role of social structures in forming gender inequalities, this study examines the effect of occupational attributes on the gender earnings gap over four decades. Using the IPUMS-USA from 1970 to 2010, the paper shows that occupational attributes cannot be reduced to the aggregate attributes of their individual incumbents. Rather, the effect of occupations on the gender earnings gap goes far beyond both the distributive role of occupational segregation and the effect of individual wage-related characteristics. Furthermore, occupations not only explain a significant portion of net gender pay gaps, but have also contributed to the narrowing of the gaps over the past several decades, as occupational attributes that favor women's pay have become more dominant over time. Copyright © 2015 Elsevier Inc. All rights reserved.

Challenges and Gaps in Children's Transition from Early Childhood Development to Grade One in Zimbabwe

ERIC Educational Resources Information Center

Chikwiri, E.; Musiyiwa, J.

2017-01-01

The study focused on challenges and gaps faced by children during the transition period from early childhood development (ECD) to primary education and possible solutions to them. It adopted the qualitative methodological approach through the use of Focus Group Discussions with councillors, education officials, child care workers, chiefs, parents…

Using Higher Order Cognitive Questions in the Primary Classroom To Improve Comprehension.

ERIC Educational Resources Information Center

Coolidge, Susan W.

A teaching team leader and second grade teacher designed and implemented a 10-week practicum intervention meant to improve the inferential comprehension of 105 second graders whose reading scores on the Ginn Mastery Tests revealed a gap between inferential and literal comprehension. It was reasoned that the gap would decrease if teachers were…

Single Sex Math Classes: What and for Whom? One School's Experiences.

ERIC Educational Resources Information Center

Durost, Richard A.

1996-01-01

Presque Isle (Maine) High School has offered a section of all-girls algebra for seven years. The intent was to narrow the gap between 11th-grade boys' and girls' math achievement scores and create a more comfortable learning atmosphere for girls. The achievement score gap has decreased from 72 to 16 points. (MLH)

Subgroup Achievement and Gap Trends: New Hampshire, 2010

ERIC Educational Resources Information Center

Center on Education Policy, 2010

2010-01-01

This paper profiles the student subgroup achievement and gap trends in New Hampshire for 2010. New Hampshire's demographic profile is such that, with the exception of Latino students at the elementary level, there are fewer than 500 students in the racial/ethnic subgroups at the various grade levels, and therefore these groups are too small to…

Bridging the Rural-Urban Literacy Gap in China: A Mediation Analysis of Family Effects

ERIC Educational Resources Information Center

Wang, Jingying; Li, Hui; Wang, Dan

2018-01-01

This study examines the effects of family involvement on the literacy gap between rural and urban Chinese primary students via mediation analysis. Altogether, 1080 students in Grades 1, 3, and 5 were randomly sampled from three urban and three rural primary schools from Shandong and Guizhou Provinces, representing eastern and western China,…

Subgroup Achievement and Gap Trends: Hawaii

ERIC Educational Resources Information Center

Center on Education Policy, 2010

2010-01-01

Hawaii showed improvement in reading and math in grade 8 at the basic, proficient, and advanced levels for Asian and white students, low income students, and boys and girls. Gains in math tended to be larger than in reading. Trends in closing achievement gaps were mixed. Comparable data were available from 2007 through 2009. (Contains 9 tables.)…

Social Support and Socioeconomic Status Predict Secondary Students' Grades and Educational Plans Indifferently across Immigrant Group and Gender

ERIC Educational Resources Information Center

Ulriksen, Robin; Sagatun, Åse; Zachrisson, Henrik Daae; Waaktaar, Trine; Lervåg, Arne Ola

2015-01-01

Social support and socioeconomic status (SES) have received considerable attention in explaining academic achievement and the achievement gap between students with ethic majority and immigrant background, and between boys and girls. Using a Structural Equation Modeling approach we examine (1) if there exist a gap in school achievements between…

Analyzing Performance by Grade 10 Hispanic High School Students on the Massachusetts State Assessment. Issues & Answers. REL 2009-No. 071

ERIC Educational Resources Information Center

Sanchez, Maria Teresa; Ehrlich, Stacy; Midouhas, Emily; O'Dwyer, Laura

2009-01-01

Massachusetts policymakers recently expressed a desire to better understand Hispanic student achievement patterns in their state. Scores on the Massachusetts Comprehensive Assessment System (MCAS) tests have consistently revealed a gap in performance between Hispanic students and students from other subgroups, a gap corresponding to national…

Eco-friendly porous concrete using bottom ash aggregate for marine ranch application.

PubMed

Lee, Byung Jae; Prabhu, G Ganesh; Lee, Bong Chun; Kim, Yun Yong

2016-03-01

This article presents the test results of an investigation carried out on the reuse of coal bottom ash aggregate as a substitute material for coarse aggregate in porous concrete production for marine ranch applications. The experimental parameters were the rate of bottom ash aggregate substitution (30%, 50% and 100%) and the target void ratio (15%, 20% and 25%). The cement-coated granular fertiliser was substituted into a bottom ash aggregate concrete mixture to improve marine ranch applications. The results of leaching tests revealed that the bottom ash aggregate has only a negligible amount of the ten deleterious substances specified in the Ministry of Environment - Enforcement Regulation of the Waste Management Act of Republic Korea. The large amount of bubbles/air gaps in the bottom ash aggregate increased the voids of the concrete mixtures in all target void ratios, and decreased the compressive strength of the porous concrete mixture; however, the mixture substituted with 30% and 10% of bottom ash aggregate and granular fertiliser, respectively, showed an equal strength to the control mixture. The sea water resistibility of the bottom ash aggregate substituted mixture was relatively equal to that of the control mixture, and also showed a great deal of improvement in the degree of marine organism adhesion compared with the control mixture. No fatality of fish was observed in the fish toxicity test, which suggested that bottom ash aggregate was a harmless material and that the combination of bottom ash aggregate and granular fertiliser with substitution rates of 30% and 10%, respectively, can be effectively used in porous concrete production for marine ranch application. © The Author(s) 2015.

The Impact of Single-Gender Classrooms on Student Achievement in Seventh Grade Math Classes

ERIC Educational Resources Information Center

Sutton, Antwon M.

2009-01-01

A mathematics achievement gap exists between males and females. The measurement of achievement was compared between single-gender and traditional classroom students in the 7th grade to assess whether or not a single-gender environment affected their scores. The Measures of Academic Progress (MAP) state assessment served as the data collection…

Benefits of Repeated Reading Intervention for Low-Achieving Fourth- and Fifth-Grade Students

ERIC Educational Resources Information Center

Vadasy, Patricia F.; Sanders, Elizabeth A.

2008-01-01

Many students have difficulty achieving reading fluency, and nearly half of fourth graders are not fluent readers in grade-level texts. Intensive and focused reading practice is recommended to help close the gap between students with poor fluency and their average reading peers. In this study, the "Quick Reads" fluency program was used…

Algebra I Achievement of Eighth Grade Mexican American Students Using Cooperative Learning versus Traditional Instruction

ERIC Educational Resources Information Center

Bunrasi, John Bosco Tuptip

2012-01-01

The purpose of this study was to examine constructivist-based algebra lessons and a cooperative construct to address the achievement gap between White (non-Hispanic) and Mexican American 8th grade students at a southern California middle school. The lessons were designed to facilitate social interdependence which promoted peer-to-peer interaction…

Descending the Tower: Lessons Learned in a First Grade Classroom.

ERIC Educational Resources Information Center

Ford, Michael P.

In light of concerns that previous staff development projects did not truly capture life in the classroom, and that there may be a gap between one's previous elementary and current university teaching experiences, a teacher educator used a semester sabbatical to shadow six first-grade teachers in order to inform thinking and practice in teaching…

Transition Points for the Gender Gap in Computer Enjoyment

ERIC Educational Resources Information Center

Christensen, Rhonda; Knezek, Gerald; Overall, Theresa

2005-01-01

Data gathered from 10,000 Texas public school students in Grades 3-12 over the years 2000, 2001, 2002, and 2005 were analyzed to replicate findings first discovered as a byproduct of evaluation of a large scale U.S. Department of Education Technology Innovation Challenge Grant. Initial findings were that girls in Grades 4 and 5 reported enjoying…

Engineering Design Processes in Seventh-Grade Classrooms: Bridging the Engineering Education Gap

ERIC Educational Resources Information Center

English, Lyn D.; Hudson, Peter B.; Dawes, Les

2012-01-01

This paper reports on some findings from the first year of a three-year longitudinal study, in which seventh- to ninth-graders were introduced to engineering education. Specifically, the paper addresses students' responses to an initial design activity involving bridge construction, which was implemented at the end of seventh grade. This paper…

Using GRADE as a framework to guide research on the sexual and reproductive health and rights (SRHR) of women living with HIV - methodological opportunities and challenges.

PubMed

Siegfried, Nandi; Narasimhan, Manjulaa; Kennedy, Caitlin E; Welbourn, Alice; Yuvraj, Anandi

2017-09-01

In March 2016, WHO reviewed evidence to develop global recommendations on the sexual and reproductive health and rights (SRHR) of women living with HIV. Systematic reviews and a global survey of women living with HIV informed the guideline development decision-making process. New recommendations covered abortion, Caesarean section, safe disclosure, and empowerment and self-efficacy interventions. Identification of key research gaps is part of the WHO guidelines development process, but consistent methods to do so are lacking. Our method aimed to ensure consistency and comprised the systematic application of a framework based on GRADE (Grading of Recommendations, Assessment, Development and Evaluation) to the process. The framework incorporates the strength and quality rating of recommendations and the priorities reported by women in the survey to inform research prioritisation. For each gap, we also articulated: (1) the most appropriate and robust study design to answer the question; (2) alternative pragmatic designs if the ideal design is not feasible; and (3) the methodological challenges facing researchers through identifying potential biases. We found 12 research gaps and identified five appropriate study designs to address the related questions: (1) Cross-sectional surveys; (2) Qualitative interview-driven studies; (3) Registries; (4) Randomised controlled trials; and (5) Medical record audit. Methodological challenges included selection, recruitment, misclassification, measurement and contextual biases, and confounding. In conclusion, a framework based on GRADE can provide a systematic approach to identifying research gaps from a WHO guideline. Incorporation of the priorities of women living with HIV into the framework systematically ensures that women living with HIV can shape future policy decisions affecting their lives. Implementation science and participatory research are appropriate over-arching approaches to enhance uptake of interventions and to ensure inclusion of women living with HIV at all stages of the research process.

A new mass mortality of juvenile Protoceratops and size-segregated aggregation behaviour in juvenile non-avian dinosaurs.

PubMed

Hone, David W E; Farke, Andrew A; Watabe, Mahito; Shigeru, Suzuki; Tsogtbaatar, Khishigjav

2014-01-01

Monodominant bonebeds are a relatively common occurrence for non-avian dinosaurs, and have been used to infer associative, and potentially genuinely social, behavior. Previously known assemblages are characterized as either mixed size-classes (juvenile and adult-sized specimens together) or single size-classes of individuals (only juveniles or only adult-sized individuals within the assemblage). In the latter case, it is generally unknown if these kinds of size-segregated aggregations characterize only a particular size stage or represent aggregations that happened at all size stages. Ceratopsians ("horned dinosaurs") are known from both types of assemblages. Here we describe a new specimen of the ceratopsian dinosaur Protoceratops andrewsi, Granger and Gregory 1923 from Mongolia representing an aggregation of four mid-sized juvenile animals. In conjunction with existing specimens of groups of P. andrewsi that includes size-clustered aggregations of young juveniles and adult-sized specimens, this new material provides evidence for some degree of size-clustered aggregation behaviour in Protoceratops throughout ontogeny. This continuity of size-segregated (and presumably age-clustered) aggregation is previously undocumented in non-avian dinosaurs. The juvenile group fills a key gap in the available information on aggregations in younger ceratopsians. Although we support the general hypothesis that many non-avian dinosaurs were gregarious and even social animals, we caution that evidence for sociality has been overstated and advocate a more conservative interpretation of some data of 'sociality' in dinosaurs.

A New Mass Mortality of Juvenile Protoceratops and Size-Segregated Aggregation Behaviour in Juvenile Non-Avian Dinosaurs

PubMed Central

Hone, David W. E.; Farke, Andrew A.; Watabe, Mahito; Shigeru, Suzuki; Tsogtbaatar, Khishigjav

2014-01-01

Background Monodominant bonebeds are a relatively common occurrence for non-avian dinosaurs, and have been used to infer associative, and potentially genuinely social, behavior. Previously known assemblages are characterized as either mixed size-classes (juvenile and adult-sized specimens together) or single size-classes of individuals (only juveniles or only adult-sized individuals within the assemblage). In the latter case, it is generally unknown if these kinds of size-segregated aggregations characterize only a particular size stage or represent aggregations that happened at all size stages. Ceratopsians (“horned dinosaurs”) are known from both types of assemblages. Methods/Principal Findings Here we describe a new specimen of the ceratopsian dinosaur Protoceratops andrewsi, Granger and Gregory 1923 from Mongolia representing an aggregation of four mid-sized juvenile animals. In conjunction with existing specimens of groups of P. andrewsi that includes size-clustered aggregations of young juveniles and adult-sized specimens, this new material provides evidence for some degree of size-clustered aggregation behaviour in Protoceratops throughout ontogeny. This continuity of size-segregated (and presumably age-clustered) aggregation is previously undocumented in non-avian dinosaurs. Conclusions The juvenile group fills a key gap in the available information on aggregations in younger ceratopsians. Although we support the general hypothesis that many non-avian dinosaurs were gregarious and even social animals, we caution that evidence for sociality has been overstated and advocate a more conservative interpretation of some data of ‘sociality’ in dinosaurs. PMID:25426957

Strength Characteristics of Quarry Dust in Replacement of Sand

NASA Astrophysics Data System (ADS)

Shyam Prakash, K.; Hanumantha Rao, Ch, Dr

2017-08-01

The replacement of natural fine aggregate by using quarry dust leads to consumption of generated quarry dust, the requirement of land fill area can be reduced and solves the natural sand scarcity problem. The sand availability as a fine aggregate at low cost which needs the reason to search as a alternative material. Even it causes saddle to dump the crusher dust at one place which causes environmental pollution. The chemical analysis, specific gravity, sieve analysis and compressive strength is identified for various percentage and grades of concrete by replacement of sand with quarry dust.

Can mixed assessment methods make biology classes more equitable?

PubMed

Cotner, Sehoya; Ballen, Cissy J

2017-01-01

Many factors have been proposed to explain the attrition of women in science, technology, engineering and math fields, among them the lower performance of women in introductory courses resulting from deficits in incoming preparation. We focus on the impact of mixed methods of assessment, which minimizes the impact of high-stakes exams and rewards other methods of assessment such as group participation, low-stakes quizzes and assignments, and in-class activities. We hypothesized that these mixed methods would benefit individuals who otherwise underperform on high-stakes tests. Here, we analyze gender-based performance trends in nine large (N > 1000 students) introductory biology courses in fall 2016. Females underperformed on exams compared to their male counterparts, a difference that does not exist with other methods of assessment that compose course grade. Further, we analyzed three case studies of courses that transitioned their grading schemes to either de-emphasize or emphasize exams as a proportion of total course grade. We demonstrate that the shift away from an exam emphasis consequently benefits female students, thereby closing gaps in overall performance. Further, the exam performance gap itself is reduced when the exams contribute less to overall course grade. We discuss testable predictions that follow from our hypothesis, and advocate for the use of mixed methods of assessments (possibly as part of an overall shift to active learning techniques). We conclude by challenging the student deficit model, and suggest a course deficit model as explanatory of these performance gaps, whereby the microclimate of the classroom can either raise or lower barriers to success for underrepresented groups in STEM.

Can mixed assessment methods make biology classes more equitable?

PubMed Central

Ballen, Cissy J.

2017-01-01

Many factors have been proposed to explain the attrition of women in science, technology, engineering and math fields, among them the lower performance of women in introductory courses resulting from deficits in incoming preparation. We focus on the impact of mixed methods of assessment, which minimizes the impact of high-stakes exams and rewards other methods of assessment such as group participation, low-stakes quizzes and assignments, and in-class activities. We hypothesized that these mixed methods would benefit individuals who otherwise underperform on high-stakes tests. Here, we analyze gender-based performance trends in nine large (N > 1000 students) introductory biology courses in fall 2016. Females underperformed on exams compared to their male counterparts, a difference that does not exist with other methods of assessment that compose course grade. Further, we analyzed three case studies of courses that transitioned their grading schemes to either de-emphasize or emphasize exams as a proportion of total course grade. We demonstrate that the shift away from an exam emphasis consequently benefits female students, thereby closing gaps in overall performance. Further, the exam performance gap itself is reduced when the exams contribute less to overall course grade. We discuss testable predictions that follow from our hypothesis, and advocate for the use of mixed methods of assessments (possibly as part of an overall shift to active learning techniques). We conclude by challenging the student deficit model, and suggest a course deficit model as explanatory of these performance gaps, whereby the microclimate of the classroom can either raise or lower barriers to success for underrepresented groups in STEM. PMID:29281676

Patterns and Trends in Achievement Gaps in Malaysian Secondary Schools (1999-2011): Gender, Ethnicity, and Socioeconomic Status

ERIC Educational Resources Information Center

Saw, Guan Kung

2016-01-01

Educational inequality is a highly debated yet empirically understudied topic in Malaysia. This paper examines the patterns and trends of academic achievement gaps by student social groups in Malaysia, drawing upon nationally representative data for the most recent four cohorts (1999, 2003, 2007, and 2011) of eighth-grade Malaysian students from…

The Teachers' Perspectives on Effective Strategies for African American Students Embedded in the GO Math Program

ERIC Educational Resources Information Center

Sumter, Jeremiah, Jr.

2016-01-01

Research and history has demonstrated the overwhelming disparity and gap of mathematical achievement between African Americans and their White counterparts. According to the National Assessment of Educational Progress (NAEP), the achievement gap on a national level is prevalent. The USA jurisdiction has Black 8th grade math students results at 12%…

Bridging the Numeracy Gap for Students in Low SES Communities: The Power of a Whole School Approach

ERIC Educational Resources Information Center

Gervasoni, Ann; Parish, Linda; Upton, Cait; Hadden, Teresa; Turkenburg, Kathie; Bevan, Kate; Livesey, Carole; Thompson, Deirdre; Croswell, Melissa; Southwell, Julie

2010-01-01

This paper explores the impact of the "Bridging the Numeracy Gap Project" on the whole-number learning of Prep and Grade 1 students living in a low Socio-Economic Status (SES) community. The findings suggest that an approach that includes a specialist mathematics teacher who provides specialised programs for mathematically vulnerable…

From Noncompetence to Exceptional Talent: Exploring the Range of Academic Achievement within and between Grade Levels

ERIC Educational Resources Information Center

Gagne, Francoys

2005-01-01

This article analyzes the magnitude of individual differences in academic achievement and their growth over the first 9 years of schooling. The author anchors the widening-gap phenomenon on the theoretical recognition of large individual differences in learning pace, which logically leads over time to an increasing gap in knowledge and skills…

A Test of Leading Explanations for the College Racial-Ethnic Achievement Gap: Evidence from a Longitudinal Case Study

ERIC Educational Resources Information Center

Martin, Nathan D.; Spenner, Kenneth I; Mustillo, Sarah A.

2017-01-01

In this study, we examined racial/ethnic differences in grade point average (GPA) among students at a highly selective, private university who were surveyed before matriculation and during the first, second and fourth college years, and assessed prominent explanations for the Black-White and Latino-White college achievement gap. We found that…

Permanent deformation characteristics of Oregon mixes using the asphalt pavement analyzer : final report.

DOT National Transportation Integrated Search

2004-01-01

The Asphalt Pavement Analyzer (APA) device was used to characterize the impacts of various mix factors on the development of permanent deformation dense-graded mixes. Factors investigated included: aggregate size of 12.5 and 19 mm (0.5 and 0.75 in), ...

Monitoring and modeling of pavement response and performance task B : New York volume 3, I90.

DOT National Transportation Integrated Search

2012-05-01

This research presents the evaluation and comparison of two Portland-cement concrete (PCC) pavement test : sections with cement-treated permeable bases (CTPB) and dense-graded aggregate bases (DGAB) on the Interstate : 90 Thruway in New York. Two ins...

An Investigation on a Crystalline-Silicon Solar Cell with Black Silicon Layer at the Rear.

PubMed

Zhou, Zhi-Quan; Hu, Fei; Zhou, Wen-Jie; Chen, Hong-Yan; Ma, Lei; Zhang, Chi; Lu, Ming

2017-12-15

Crystalline-Si (c-Si) solar cell with black Si (b-Si) layer at the rear was studied in order to develop c-Si solar cell with sub-band gap photovoltaic response. The b-Si was made by chemical etching. The c-Si solar cell with b-Si at the rear was found to perform far better than that of similar structure but with no b-Si at the rear, with the efficiency being increased relatively by 27.7%. This finding was interesting as b-Si had a large specific surface area, which could cause high surface recombination and degradation of solar cell performance. A graded band gap was found to form at the rear of the c-Si solar cell with b-Si layer at the rear. This graded band gap tended to expel free electrons away from the rear, thus reducing the probability of electron-hole recombination at b-Si and improving the performance of c-Si solar cell.

Teacher expectations, classroom context, and the achievement gap.

PubMed

McKown, Clark; Weinstein, Rhona S

2008-06-01

In two independent datasets with 1872 elementary-aged children in 83 classrooms, Studies 1 and 2 examined the role of classroom context in moderating the relationship between child ethnicity and teacher expectations. For Study 1 overall and Study 2 mixed-grade classrooms, in ethnically diverse classrooms where students reported high levels of differential teacher treatment (PDT) towards high and low achieving students, teacher expectations of European American and Asian American students were between .75 and 1.00 standard deviations higher than teacher expectations of African American and Latino students with similar records of achievement. In highly diverse low-PDT classrooms in Study 1 and highly diverse low-PDT mixed-grade classrooms in Study 2, teachers held similar expectations for all students with similar records of achievement. Study 3 estimated the contribution of teacher expectations to the year-end ethnic achievement gap in high- and low-bias classrooms. In high-bias classrooms, teacher expectancy effects accounted for an average of .29 and up to .38 standard deviations of the year-end ethnic achievement gap.

Probing the Relative Photoinjection Yields of Monomer and Aggregated Dyes into ZnO Crystals.

PubMed

King, Laurie A; Parkinson, B A

2017-01-17

Cyanine dyes, often used in dye-sensitized solar cells (DSSCs), form a range of molecular species from monomers to large H and J aggregates in both solution and when adsorbed at a photoelectrode surface. To determine the relative capability of the different dye species to inject photoexcited electrons into a wideband gap oxide semiconductor, sensitization at a single-crystal zinc oxide surface was studied by simultaneous attenuated reflection (ATR) ultraviolet-visible (UV-vis) absorption and photocurrent spectroscopy measurements. ATR measurements enable identification of the dye species populating the surface with simultaneous photocurrent spectroscopy to identify the contribution of the various dye forms to photocurrent signal. We study the dye 2,2'-carboxymethylthiodicarbocyanine bromide that is particularly prone to aggregation both in solution and at the surface of sensitized oxide semiconductors.

Stakeholders' Perceptions on Mandated Student Retention in Early Childhood

ERIC Educational Resources Information Center

Mankins, Jennifer K.

2018-01-01

Reading is one of the primary goals of the early elementary grades. When students start to struggle with this complex skill, educators and parents search for solutions to rectify quickly mounting gaps before a child falls too far behind. In the State of Oklahoma, lawmakers have passed a law requiring mandatory 3rd grade retention for students who…

Assessing Equity beyond Knowledge- and Skills-Based Outcomes: A Comparative Ethnography of Two Fourth-Grade Reform-Based Science Classrooms

ERIC Educational Resources Information Center

Carlone, Heidi B.; Haun-Frank, Julie; Webb, Angela

2011-01-01

When evaluating equity, researchers often look at the "achievement gap." Privileging knowledge and skills as primary outcomes of science education misses other, more subtle, but critical, outcomes indexing inequitable science education. In this comparative ethnography, we examined what it meant to "be scientific" in two fourth-grade classes taught…

Development of the Literacy Achievement Gap: A Longitudinal Study of Kindergarten through Third Grade

ERIC Educational Resources Information Center

Foster, Wayne A.; Miller, Merideth

2007-01-01

Purpose: The major goal of this study was to specify the developmental trajectories for phonics and early text comprehension skills of children from kindergarten through third grade. Method: Data from the Early Childhood Longitudinal Study (N = 12,261) were used in this study. The participants were divided into 3 school readiness groups based on…

Investigation of Usability as Aggregate of Different Originated Rocks

NASA Astrophysics Data System (ADS)

Başpinar Tuncay, Ebru; Kilinçarslan, Şemsettin; Yağmurlu, Fuzuli

2016-10-01

The general properties of aggregate can determine the performance and durability of the concrete. In this study, mineralogical, petrographic, mechanical, physical and chemical properties of the rock samples of different origin (limestone, recrystallized limestone, dolomite, sand and gravel, tephra-phonolite, trachybasalt) were determined. Samples were obtained from different origin rocks units and they have been classified in three different sizes of aggregate with crushing and screening method. Grading, classification of particle, loose bulk density, water absorption ratio, flakiness index, coefficient of Los Angeles, resistance to freeze-loosening and alkali-silica reaction of aggregates and organic matter determination has been determined. The rocks have been investigated in compliance with the relevant standards. Trachybasalt and dolomite have higher particle density than other rocks. In addition, strength and flexural strength of these rocks are higher than other rocks. Tephra-phonolite has the lowest water absorption rate. At the same time resistance to freeze loosening of Tephra- phonolite is lower than the other rocks. Resistance to fragmentation and the resistance to wear of all of rocks are quite high. Sand and gravel, tephra-phonolite and trachybasalt are evaluated in terms of alkali-silica reaction. Sand and gravel are more reactive than the other aggregates. Organic matter content of the aggregates is low for the quality of aggregate. Also high correlation between some properties of aggregates was observed. For example, high correlation between compressive strength and flexural strength, water absorption and porosity, resistance to fragmentation and the resistance to ware (Micro-Deval).

Gap junctions and connexin hemichannels in the regulation of haemostasis and thrombosis.

PubMed

Vaiyapuri, Sakthivel; Flora, Gagan D; Gibbins, Jonathan M

2015-06-01

Platelets are involved in the maintenance of haemostasis but their inappropriate activation leads to thrombosis, a principal trigger for heart attack and ischaemic stroke. Although platelets circulate in isolation, upon activation they accumulate or aggregate together to form a thrombus, where they function in a co-ordinated manner to prevent loss of blood and control wound repair. Previous report (1) indicates that the stability and functions of a thrombus are maintained through sustained, contact-dependent signalling between platelets. Given the role of gap junctions in the co-ordination of tissue responses, it was hypothesized that gap junctions may be present within a thrombus and mediate intercellular communication between platelets. Therefore studies were performed to explore the presence and functions of connexins in platelets. In this brief review, the roles of hemichannels and gap junctions in the control of thrombosis and haemostasis and the future directions for this research will be discussed.

A social and academic enrichment program promotes medical school matriculation and graduation for disadvantaged students.

PubMed

Keith, L; Hollar, D

2012-07-01

This study assessed the impact of a pre-medical pipeline program on successful completion of medical school and the capacity of this program to address achievement gaps experienced by disadvantaged students. The University of North Carolina (USA) Medical Education Development (MED) program provides intensive academic and test skills preparation for admission to medical, dental, and other allied health professions schools. This retrospective study evaluated the academic progress of a longitudinal sample of 1738 disadvantaged college students who completed MED between 1974 and 2001. Data sources included MED participant data, medical school admissions data for the host school, aggregate data from the Association of American Medical Colleges (AAMC), and individual MED participant data from AAMC. Methods of analysis utilized Chi-square, independent samples t test, and logistic regression to examine associations between factors. Of the 935 students in MED from 1974 to 2001, who had indicated an interest in medical school, 887 (94.9%) successfully matriculated and 801 (85.7%) successfully earned the MD degree. Using logistic regression, factors that were significantly correlated with earning the medical degree included the student's race, college undergraduate total and science grade point averages, with Hispanic, African American, and Native American participants earning the medical degree at rates comparable to Caucasian participants. MED students successfully earned the MD degree despite having significantly lower Medical College Admissions Test (MCAT) scores and undergraduate grade point averages compared to all United States medical school applicants: MCAT scores had little relationship with student's success. These findings suggest that an intensive, nine-week, pre-medical academic enrichment program that incorporates confidence-building and small-group tutoring and peer support activities can build a foundation on which disadvantaged students can successfully earn matriculation to and graduation from medical school.

High Modulus Asphalt Concrete with Dolomite Aggregates

NASA Astrophysics Data System (ADS)

Haritonovs, V.; Tihonovs, J.; Smirnovs, J.

2015-11-01

Dolomite is one of the most widely available sedimentary rocks in the territory of Latvia. Dolomite quarries contain about 1,000 million tons of this material. However, according to Latvian Road Specifications, this dolomite cannot be used for average and high intensity roads because of its low quality, mainly, its LA index (The Los Angeles abrasion test). Therefore, mostly the imported magmatic rocks (granite, diabase, gabbro, basalt) or imported dolomite are used, which makes asphalt expensive. However, practical experience shows that even with these high quality materials roads exhibit rutting, fatigue, and thermal cracks. The aim of the research is to develop a high performance asphalt concrete for base and binder courses using only locally available aggregates. In order to achieve resistance against deformations at a high ambient temperature, a hard grade binder was used. Workability, fatigue and thermal cracking resistance, as well as sufficient water resistance is achieved by low porosity (3-5%) and higher binder content compared to traditional asphalt mixtures. The design of the asphalt includes a combination of empirical and performance based tests, which in laboratory circumstances allow simulating traffic and environmental loads. High performance AC 16 base asphalt concrete was created using local dolomite aggregate with polymer modified (PMB 10/40-65) and hard grade (B20/30) bitumen. The mixtures were specified based on fundamental properties in accordance with EN 13108-1 standard.

Environmental Literacy in Madeira Island (Portugal): The Influence of Demographic Variables

ERIC Educational Resources Information Center

Spinola, Hélder

2016-01-01

Demographic factors are among those that influence environmental literacy and, particularly, environmentally responsible behaviours, either directly or due to an aggregation effect dependent on other types of variables. Present study evaluates a set of demographic variables as predictors for environmental literacy among 9th grade students from…

Fall 2013 International Comparisons

ERIC Educational Resources Information Center

Northwest Evaluation Association, 2014

2014-01-01

This Fall report is an aggregated statistical analysis of Measures of Academic Progress® (MAP®) data from international schools. The report provides a consistent means of comparisons of specific sub-groups by subject and grade, which allows partners to compare their MAP® results with other schools within their region or membership organization.…

7 CFR 51.778 - Slightly colored.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Slightly colored. 51.778 Section 51.778 Agriculture... Standards for Grades of Florida Grapefruit Definitions § 51.778 Slightly colored. Slightly colored means that except for an aggregate area of green color which does not exceed the area of a circle 2 inches...

7 CFR 51.778 - Slightly colored.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Slightly colored. 51.778 Section 51.778 Agriculture... Standards for Grades of Florida Grapefruit Definitions § 51.778 Slightly colored. Slightly colored means that except for an aggregate area of green color which does not exceed the area of a circle 2 inches...

7 CFR 51.778 - Slightly colored.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Slightly colored. 51.778 Section 51.778 Agriculture... Standards for Grades of Florida Grapefruit Definitions § 51.778 Slightly colored. Slightly colored means that except for an aggregate area of green color which does not exceed the area of a circle 2 inches...

7 CFR 51.771 - Fairly well colored.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Fairly well colored. 51.771 Section 51.771 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Florida Grapefruit Definitions § 51.771 Fairly well colored. Fairly well colored means that except for an aggregate area of green color which...

7 CFR 51.771 - Fairly well colored.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Fairly well colored. 51.771 Section 51.771 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Florida Grapefruit Definitions § 51.771 Fairly well colored. Fairly well colored means that except for an aggregate area of green color which...

7 CFR 51.778 - Slightly colored.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Slightly colored. 51.778 Section 51.778 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Florida Grapefruit Definitions § 51.778 Slightly colored. Slightly colored means that except for an aggregate area of green color which does not...

7 CFR 51.778 - Slightly colored.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Slightly colored. 51.778 Section 51.778 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Florida Grapefruit Definitions § 51.778 Slightly colored. Slightly colored means that except for an aggregate area of green color which does not...

Direct band gap measurement of Cu(In,Ga)(Se,S){sub 2} thin films using high-resolution reflection electron energy loss spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heo, Sung; College of Information and Communication Engineering, Sungkyunkwan University, Cheoncheon-dong 300, Jangan-gu, Suwon 440-746; Lee, Hyung-Ik

2015-06-29

To investigate the band gap profile of Cu(In{sub 1−x},Ga{sub x})(Se{sub 1−y}S{sub y}){sub 2} of various compositions, we measured the band gap profile directly as a function of in-depth using high-resolution reflection energy loss spectroscopy (HR-REELS), which was compared with the band gap profile calculated based on the auger depth profile. The band gap profile is a double-graded band gap as a function of in-depth. The calculated band gap obtained from the auger depth profile seems to be larger than that by HR-REELS. Calculated band gaps are to measure the average band gap of the spatially different varying compositions with respectmore » to considering its void fraction. But, the results obtained using HR-REELS are to be affected by the low band gap (i.e., out of void) rather than large one (i.e., near void). Our findings suggest an analytical method to directly determine the band gap profile as function of in-depth.« less

An Examination of the Achievement Gap and School A-F Letter Grades in a Southwest County in the United States

ERIC Educational Resources Information Center

Jacobson, Jason A.

2016-01-01

Research has suggested the "No Child Left Behind Act" passed in 2001 has resulted in narrowed curriculum and a failed attempt at its primary objective to close the achievement gap. Understanding changes that have occurred in student achievement from 2011 to 2014 of the NCLB requirements is the focus of this quantitative ex-post facto…

Tackling the Achievement Gap Head on: A Background and Discussion Paper for Community Groups Interested in Helping All Children Succeed in School

ERIC Educational Resources Information Center

Mueller, Dan

2005-01-01

The achievement gap is clearly visible throughout the school years, from grade-school test scores through high school graduation and higher education. It divides American Indian, Asian, Black, Latino, and White students, and it divides the economically advantaged from the disadvantaged regardless of their race/ethnicity. Under the federal No Child…

Research on the performance of sand-based environmental-friendly water permeable bricks

NASA Astrophysics Data System (ADS)

Cai, Runze; Mandula; Chai, Jinyi

2018-02-01

This paper examines the effects of the amount of admixture, the water cement ratio, the aggregate grading, and the cement aggregate ratio on the mechanical service properties and of porous concrete pavement bricks including strength, water permeability, frost resistance, and wear resistance. The admixture can enhance the performance of water permeable brick, and optimize the design mix. Experiments are conducted to determine the optimal mixing ratios which are given as; (1) the admixture (self-developed) within the content of 5% of the cement quality; (2) water-cement ratio equal to 0.34; (3) cement-aggregate ratio equal to 0.25; (4) fine aggregate of 70% (particle size 0.6-2.36mm); and coarse aggregate of 30% (particle size: 2.36-4.75mm). The experimental results that the sand-based permeable concrete pavement brick has a strength of 35.6MPa and that the water permeability coefficient is equal to 3.5×10-2cm/s. In addition, it was found that the concrete water permeable brick has good frost resistance and surface wear resistance, and that the its production costs are much lower than the similar sand-based water permeable bricks in China.

Analysis of Knowledge-Sharing Evolutionary Game in University Teacher Team

ERIC Educational Resources Information Center

Huo, Mingkui

2013-01-01

The knowledge-sharing activity is a major drive force behind the progress and innovation of university teacher team. Based on the evolutionary game theory, this article analyzes the knowledge-sharing process model of this team, studies the influencing mechanism of various factors such as knowledge aggregate gap, incentive coefficient and risk…

Cu doped diamond: Effect of charge state and defect aggregation on spin interactions in a 3d transition metal doped wide band-gap semiconductor

NASA Astrophysics Data System (ADS)

Benecha, E. M.; Lombardi, E. B.

2018-05-01

We present a first principles study of Cu in diamond using DFT+U electronic structure methods, by carefully considering the impact of co-doping, charge state, and Fermi level position on its stability, lattice location, spin states, and electronic properties. We show that the energetic stability and spin states of Cu are strongly dependent on the Fermi level position and the type of diamond co-doping, with Cu being energetically more favorable in n-type or p-type co-doped diamond compared to intrinsic diamond. Since Cu has been predicted to order magnetically in a number of other wide band-gap semiconductors, we have also evaluated this possibility for Cu doped diamond. We show that while Cu exhibits strong spin interactions at specific interatomic separations in diamond, a detailed consideration of the impact of Fermi level position and Cu aggregation precludes magnetic ordering, with Cu forming non-magnetic, antiferromagnetic, or paramagnetic clusters. These results have important implications in the understanding of the properties of transition metal dopants in diamond for device applications.

Instructional Factors that Contribute to Achievement in Reading for African American Male Students in Grades K-5 in an Urban School in Georgia

ERIC Educational Resources Information Center

Robinson, Isaac, III

2010-01-01

According to the National Assessment of Educational Progress, reading skills for African American male students in Grades 4 and 8 have improved over the past decade. However, a significant reading achievement gap still exists between African American male students and their European American counterparts. The purpose, as well as the central…

Determination of critical nucleation number for a single nucleation amyloid-β aggregation model.

PubMed

Ghosh, Preetam; Vaidya, Ashwin; Kumar, Amit; Rangachari, Vijayaraghavan

2016-03-01

Aggregates of amyloid-β (Aβ) peptide are known to be the key pathological agents in Alzheimer disease (AD). Aβ aggregates to form large, insoluble fibrils that deposit as senile plaques in AD brains. The process of aggregation is nucleation-dependent in which the formation of a nucleus is the rate-limiting step, and controls the physiochemical fate of the aggregates formed. Therefore, understanding the properties of nucleus and pre-nucleation events will be significant in reducing the existing knowledge-gap in AD pathogenesis. In this report, we have determined the plausible range of critical nucleation number (n(*)), the number of monomers associated within the nucleus for a homogenous aggregation model with single unique nucleation event, by two independent methods: A reduced-order stability analysis and ordinary differential equation based numerical analysis, supported by experimental biophysics. The results establish that the most likely range of n(*) is between 7 and 14 and within, this range, n(*) = 12 closely supports the experimental data. These numbers are in agreement with those previously reported, and importantly, the report establishes a new modeling framework using two independent approaches towards a convergent solution in modeling complex aggregation reactions. Our model also suggests that the formation of large protofibrils is dependent on the nature of n(*), further supporting the idea that pre-nucleation events are significant in controlling the fate of larger aggregates formed. This report has re-opened an old problem with a new perspective and holds promise towards revealing the molecular events in amyloid pathologies in the future. Copyright © 2015 Elsevier Inc. All rights reserved.

The Role of Shape Complementarity in the Protein-Protein Interactions

PubMed Central

Li, Ye; Zhang, Xianren; Cao, Dapeng

2013-01-01

We use a dissipative particle dynamic simulation to investigate the effects of shape complementarity on the protein-protein interactions. By monitoring different kinds of protein shape-complementarity modes, we gave a clear mechanism to reveal the role of the shape complementarity in the protein-protein interactions, i.e., when the two proteins with shape complementarity approach each other, the conformation of lipid chains between two proteins would be restricted significantly. The lipid molecules tend to leave the gap formed by two proteins to maximize the configuration entropy, and therefore yield an effective entropy-induced protein-protein attraction, which enhances the protein aggregation. In short, this work provides an insight into understanding the importance of the shape complementarity in the protein-protein interactions especially for protein aggregation and antibody–antigen complexes. Definitely, the shape complementarity is the third key factor affecting protein aggregation and complex, besides the electrostatic-complementarity and hydrophobic complementarity. PMID:24253561

The Role of Shape Complementarity in the Protein-Protein Interactions

NASA Astrophysics Data System (ADS)

Li, Ye; Zhang, Xianren; Cao, Dapeng

2013-11-01

We use a dissipative particle dynamic simulation to investigate the effects of shape complementarity on the protein-protein interactions. By monitoring different kinds of protein shape-complementarity modes, we gave a clear mechanism to reveal the role of the shape complementarity in the protein-protein interactions, i.e., when the two proteins with shape complementarity approach each other, the conformation of lipid chains between two proteins would be restricted significantly. The lipid molecules tend to leave the gap formed by two proteins to maximize the configuration entropy, and therefore yield an effective entropy-induced protein-protein attraction, which enhances the protein aggregation. In short, this work provides an insight into understanding the importance of the shape complementarity in the protein-protein interactions especially for protein aggregation and antibody-antigen complexes. Definitely, the shape complementarity is the third key factor affecting protein aggregation and complex, besides the electrostatic-complementarity and hydrophobic complementarity.

RCCS bioreactor-based modelled microgravity induces significant changes on in vitro 3D neuroglial cell cultures.

PubMed

Morabito, Caterina; Steimberg, Nathalie; Mazzoleni, Giovanna; Guarnieri, Simone; Fanò-Illic, Giorgio; Mariggiò, Maria A

2015-01-01

We propose a human-derived neuro-/glial cell three-dimensional in vitro model to investigate the effects of microgravity on cell-cell interactions. A rotary cell-culture system (RCCS) bioreactor was used to generate a modelled microgravity environment, and morphofunctional features of glial-like GL15 and neuronal-like SH-SY5Y cells in three-dimensional individual cultures (monotypic aggregates) and cocultures (heterotypic aggregates) were analysed. Cell survival was maintained within all cell aggregates over 2 weeks of culture. Moreover, compared to cells as traditional static monolayers, cell aggregates cultured under modelled microgravity showed increased expression of specific differentiation markers (e.g., GL15 cells: GFAP, S100B; SH-SY5Y cells: GAP43) and modulation of functional cell-cell interactions (e.g., N-CAM and Cx43 expression and localisation). In conclusion, this culture model opens a wide range of specific investigations at the molecular, biochemical, and morphological levels, and it represents an important tool for in vitro studies into dynamic interactions and responses of nervous system cell components to microgravity environmental conditions.

RCCS Bioreactor-Based Modelled Microgravity Induces Significant Changes on In Vitro 3D Neuroglial Cell Cultures

PubMed Central

Mazzoleni, Giovanna; Fanò-Illic, Giorgio; Mariggiò, Maria A.

2015-01-01

We propose a human-derived neuro-/glial cell three-dimensional in vitro model to investigate the effects of microgravity on cell-cell interactions. A rotary cell-culture system (RCCS) bioreactor was used to generate a modelled microgravity environment, and morphofunctional features of glial-like GL15 and neuronal-like SH-SY5Y cells in three-dimensional individual cultures (monotypic aggregates) and cocultures (heterotypic aggregates) were analysed. Cell survival was maintained within all cell aggregates over 2 weeks of culture. Moreover, compared to cells as traditional static monolayers, cell aggregates cultured under modelled microgravity showed increased expression of specific differentiation markers (e.g., GL15 cells: GFAP, S100B; SH-SY5Y cells: GAP43) and modulation of functional cell-cell interactions (e.g., N-CAM and Cx43 expression and localisation). In conclusion, this culture model opens a wide range of specific investigations at the molecular, biochemical, and morphological levels, and it represents an important tool for in vitro studies into dynamic interactions and responses of nervous system cell components to microgravity environmental conditions. PMID:25654124

GaAsP on GaP top solar cells

NASA Technical Reports Server (NTRS)

Mcneely, J. B.; Negley, G. H.; Barnett, A. M.

1985-01-01

GaAsP on GaP top solar cells as an attachment to silicon bottom solar cells are being developed. The GaAsP on GaP system offers several advantages for this top solar cell. The most important is that the gallium phosphide substrate provides a rugged, transparent mechanical substrate which does not have to be removed or thinned during processing. Additional advantages are that: (1) gallium phosphide is more oxidation resistant than the III-V aluminum compounds, (2) a range of energy band gaps higher than 1.75 eV is readily available for system efficiency optimization, (3) reliable ohmic contact technology is available from the light-emitting diode industry, and (4) the system readily lends itself to graded band gap structures for additional increases in efficiency.

Implication of alcohol consumption on aggregate wellbeing.

PubMed

Parackal, Mathew; Parackal, Sherly

2017-07-01

The effects of drinking alcohol extend beyond the individuals concerned to the wider community. While there is recognition of such a global implication, currently no study has quantified the impact of alcohol consumption on aggregate wellbeing. This study aims to address this gap and attempts to investigate the impact of various levels of alcohol consumption on aggregate happiness. The study was carried out on a random selection of participants ( n = 1,817) drawn from the 3Di consumer panel, comprising over 170,000 New Zealanders aged 18 and above. Using a subjective happiness scale (SHS) in conjunction with the Alcohol Use Disorders Identification Test (AUDIT), investigation was carried out to find whether drinking behaviour affected aggregate happiness. SHS and AUDIT scores were negatively correlated and the strength of the correlation increased with the intensity of problematic drinking. Regression analysis showed that the beta coefficient was positive for the low-risk (.074) and negative for the high-risk (-.081) category, suggesting approaches to intervene with the growing problem of alcohol consumption in modern societies. Measurements of happiness can explain the global implication of alcohol in wellbeing terms. The findings of this study indicated that low-risk drinkers affected aggregate happiness positively, whereas high-risk drinkers affected aggregate happiness negatively. While the latter observation is not new, the former raises the need to promote moderation in drinking alcohol for the common good of everyone.

Distribution of Sulfate-Reducing and Methanogenic Bacteria in Anaerobic Aggregates Determined by Microsensor and Molecular Analyses

PubMed Central

Santegoeds, Cecilia M.; Damgaard, Lars Riis; Hesselink, Gijs; Zopfi, Jakob; Lens, Piet; Muyzer, Gerard; de Beer, Dirk

1999-01-01

Using molecular techniques and microsensors for H2S and CH4, we studied the population structure of and the activity distribution in anaerobic aggregates. The aggregates originated from three different types of reactors: a methanogenic reactor, a methanogenic-sulfidogenic reactor, and a sulfidogenic reactor. Microsensor measurements in methanogenic-sulfidogenic aggregates revealed that the activity of sulfate-reducing bacteria (2 to 3 mmol of S2− m−3 s−1 or 2 × 10−9 mmol s−1 per aggregate) was located in a surface layer of 50 to 100 μm thick. The sulfidogenic aggregates contained a wider sulfate-reducing zone (the first 200 to 300 μm from the aggregate surface) with a higher activity (1 to 6 mmol of S2− m−3 s−1 or 7 × 10−9 mol s−1 per aggregate). The methanogenic aggregates did not show significant sulfate-reducing activity. Methanogenic activity in the methanogenic-sulfidogenic aggregates (1 to 2 mmol of CH4 m−3 s−1 or 10−9 mmol s−1 per aggregate) and the methanogenic aggregates (2 to 4 mmol of CH4 m−3 s−1 or 5 × 10−9 mmol s−1 per aggregate) was located more inward, starting at ca. 100 μm from the aggregate surface. The methanogenic activity was not affected by 10 mM sulfate during a 1-day incubation. The sulfidogenic and methanogenic activities were independent of the type of electron donor (acetate, propionate, ethanol, or H2), but the substrates were metabolized in different zones. The localization of the populations corresponded to the microsensor data. A distinct layered structure was found in the methanogenic-sulfidogenic aggregates, with sulfate-reducing bacteria in the outer 50 to 100 μm, methanogens in the inner part, and Eubacteria spp. (partly syntrophic bacteria) filling the gap between sulfate-reducing and methanogenic bacteria. In methanogenic aggregates, few sulfate-reducing bacteria were detected, while methanogens were found in the core. In the sulfidogenic aggregates, sulfate-reducing bacteria were present in the outer 300 μm, and methanogens were distributed over the inner part in clusters with syntrophic bacteria. PMID:10508098

Low birth weight and school readiness.

PubMed

Reichman, Nancy E

2005-01-01

In the United States black women have for decades been twice as likely as white women to give birth to babies of low birth weight who are at elevated risk for developmental disabilities. Does the black-white disparity in low birth weight contribute to the racial disparity in readiness? The author summarizes the cognitive and behavioral problems that beset many low birth weight children and notes that not only are the problems greatest for the smallest babies, but black babies are two to three times as likely as whites to be very small. Nevertheless, the racial disparities in low birth weight cannot explain much of the aggregate gap in readiness because the most serious birth weight-related disabilities affect a very small share of children. The author estimates that low birth weight explains at most 3-4 percent of the racial gap in IQ scores. The author applauds the post-1980 expansions of Medicaid for increasing rates of prenatal care use among poor pregnant women but stresses that standard prenatal medical care cannot improve aggregate birth outcomes substantially. Smoking cessation and nutrition are two prenatal interventions that show promise. Several early intervention programs have been shown to improve cognitive skills of low birth weight children. But even the most promising programs can narrow the readiness gap only a little because their benefits are greatest for heavier low birth weight children and because low birth weight explains only a small share of the gap. The author stresses the importance of reducing rates of low birth weight generally and of extending to all children who need them the interventions that have improved cognitive outcomes among low birth weight children. But because black infants are more likely to be born at the lowest birth weights, preventing low birth weight--when researchers learn how to--is likely to be more effective than early intervention in narrowing birth weight-related racial gaps in school readiness.

The Kuznets process in Malaysia.

PubMed

Randolph, S

1990-10-01

This study looks at how the Kuznets process, the structural determinants of the aggregate inequality trend during the course of economic development, is transpiring in Malaysia. A time-series test of Kuznets's hypothesis concerning the trend in participation income in the course of economic growth and its underlying structural components is conducted using data from the Malaysian Family Life Survey. The study covers the period 1968-76 during which the equalizing phase of growth was expected to take hold. Analysis determined that while many of the underlying processes which Kuznets speculated combined to generate the aggregate trend in participation income are at work in Malaysia, others are either absent or their phasing has been altered. The equalizing phase in the course of development has been delayed in arriving. Inequality in the nonagricultural sector exceeded that in the agricultural sector, and the wage gap which opened during the early phase of development declined with further development. These findings conform with Kuznets's expectations. Available time-series evidence from other currently developing countries suggests that inequality is typically higher in the nonagricultural sector during the early phase of development and that an increasing and subsequently decreasing between-sector wage gap is a broadly shared experience. This study's findings also support Kuznets's expectation that inequality within the agricultural sector can worsen in the face of dualistic agricultural development. Finally, Malaysia's trend in inequality within the nonagricultural sector exerted the greatest influence upon the aggregate trend in inequality per Kuznets's hypothesis.

Formation, Fate, and Impacts of Microscopic and Macroscopic Oil-Sediment Residues in Nearshore Marine Environments: A Critical Review

NASA Astrophysics Data System (ADS)

Gustitus, Sarah A.; Clement, T. Prabhakar

2017-12-01

Crude oil that is spilled in marine environments often interacts with suspended sediments to form residues that can impact the recovery of the affected nearshore ecosystems. When spilled oil and sediment interact, they can form either small microscopic aggregates, commonly referred to as oil-particle aggregates, or large macroscopic agglomerates, referred to as sediment-oil agglomerates or sediment-oil mats. Although these different sized oil-sediment residues have similar compositions, they are formed under different conditions and have different fates in nearshore environments; the goal of this review is to synthesize our current understanding of these two types of residues. We believe that researchers who focus solely on studying either microscopic aggregates or macroscopic agglomerates could benefit from understanding the research findings available in the other field. In this study, we compare and contrast various processes that control the formation, fate, and impacts of these two types of residues in nearshore environments and point out some of the knowledge gaps in this field. Additionally, these residues have been referred to by many names in the past, leading to confusion and misconceptions at times. In this effort, we recommend a uniform nomenclature to distinguish them based on their physical size. Our overall aim is to bridge the gap between microscopic and macroscopic oil-sediment residue literature to foster a robust exchange of ideas, which we believe can lead to the development of efficient strategies for managing oil spills that affect nearshore environments.

Development of guidelines for proper selection of finer graded aggregate base for Georgia pavements - phase I.

DOT National Transportation Integrated Search

2014-09-01

In this study, the effects of No. 810 screening contents in GAB on pavement performance and GAB strength were investigated. One : Group I (013C) source and three Group II sources (028C, 048C, and 158C) were selected and specimens were prepared for Pr...

77 FR 35253 - Alternatives to the Use of External Credit Ratings in the Regulations of the OCC

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-13

... are investment grade; or (2) The obligations are approved by the OCC. The aggregate outstanding direct...-Frank Act) contains two directives to Federal agencies including the OCC. First, section 939A directs...), seeking comment on a proposal to revise its regulations pertaining to investment securities, securities...

School Climate and Exposure to Bullying: A Multilevel Study

ERIC Educational Resources Information Center

Låftman, Sara Brolin; Östberg, Viveca; Modin, Bitte

2017-01-01

This study investigates associations between aspects of school climate, measured by students' assessments aggregated to the class level, and exposure to bullying, measured at the individual level. The data were derived from the Stockholm School Survey of 2006-2010 with information from 16,418 ninth-grade students (aged 15-16 years) distributed…

Use of Existing Data Bases in a Large Scale Correlational/Regression Study. for Period January 1977-January 1978.

ERIC Educational Resources Information Center

Greene, Jennifer C.; Kellogg, Theodore

Statewide assessment data available from two school years, two grade levels, and five sources (achievement tests; student, principal, and teacher questionnaires; and principal interviews), were aggregated to more closely investigate the relationship between student/school characteristics and student achievement. To organize this large number of…

7 CFR 51.1164 - Fairly well colored.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Fairly well colored. 51.1164 Section 51.1164... STANDARDS) United States Standards for Grades of Florida Oranges and Tangelos Definitions § 51.1164 Fairly... aggregate area of green color which does not exceed the area of a circle 1 inch (25.4 mm) in diameter, the...

7 CFR 51.1164 - Fairly well colored.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Fairly well colored. 51.1164 Section 51.1164... STANDARDS) United States Standards for Grades of Florida Oranges and Tangelos Definitions § 51.1164 Fairly... aggregate area of green color which does not exceed the area of a circle 1 inch (25.4 mm) in diameter, the...

7 CFR 51.771 - Fairly well colored.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Fairly well colored. 51.771 Section 51.771 Agriculture... Standards for Grades of Florida Grapefruit Definitions § 51.771 Fairly well colored. Fairly well colored means that except for an aggregate area of green color which does not exceed the area of a circle 1 inch...

7 CFR 51.771 - Fairly well colored.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Fairly well colored. 51.771 Section 51.771 Agriculture... Standards for Grades of Florida Grapefruit Definitions § 51.771 Fairly well colored. Fairly well colored means that except for an aggregate area of green color which does not exceed the area of a circle 1 inch...

7 CFR 51.771 - Fairly well colored.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Fairly well colored. 51.771 Section 51.771 Agriculture... Standards for Grades of Florida Grapefruit Definitions § 51.771 Fairly well colored. Fairly well colored means that except for an aggregate area of green color which does not exceed the area of a circle 1 inch...

Construction report - US Highway 36, superpave overlay of sand anti-fracture layer over AC/PCC pavement.

DOT National Transportation Integrated Search

2000-12-01

The sand anti-fracture (SAF) technology was implemented on U.S. 36 in DeKalb County, Missouri, during the summer of 2000. The SAF layer is a fine aggregate graded asphalt mixture using highly polymerized asphalt binder that gives the SAF layer the ab...

Marine Science/Business & Office. B7. CHOICE: Challenging Options in Career Education.

ERIC Educational Resources Information Center

Putnam and Northern Westchester Counties Board of Cooperative Educational Services, Yorktown Heights, NY.

The documents aggregated here comprise the grade six unit of a career education curriculum designed for migrant students. Focusing on marine science, business, and office occupations, the combined teacher and student logs contain learning activities related to nine jobs: hydrographer, marine biologist, fish hatchery technician, boat builder,…

Research on test of alkali-resistant glass fibre enhanced seawater coral aggregate concrete

NASA Astrophysics Data System (ADS)

Liu, Leiyang; Wang, Xingquan

2017-12-01

It is proposed in the 13th five-year plan that reefs of the south China sea should be constructed. In the paper, an innovative thinking was proposed for the first time in order to realize local material acquisition in island construction and life dependence on sea, namely alkali-resistant glass fibre is mixed in coralaggregate concrete as reinforcing material. The glass fibre is characterized by low price, low hardness, good dispersibility and convenient construction. Reliable guarantee is provided for widely applying the material in future projects. In the paper, an orthogonal test method is firstly applied to determine the mix proportion of grade C50 coral aggregate concrete. Then, the design plan ofmix proportion of alkali-resistant glass fibre enhanced seawater coral aggregate concrete is determined. Finally, the influence law of alkali-resistant glass fibre dosageon tensile compressiveflexture strength of seawatercoralaggregate concrete is made clear.

Studies for understanding effects of additions on the strength of cement concrete

NASA Astrophysics Data System (ADS)

Bucur, R. D.; Barbuta, M.; Konvalina, P.; Serbanoiu, A. A.; Bernas, J.

2017-09-01

The paper analyzes the effects of different types of additions introduced in concrete mix on the compressive strength. The current studies show that additions contribute to improve some characteristics of concrete and to reduce the cement dosage, so it can obtain concretes which are cheaper and friendlier with environment. In the experimental mixes were introduced: crushed natural aggregates, slag aggregates, silica fume, fly ash, chopped tire, polystyrene granule, glass fibers and metallic fibers. The experimental values of compressive strengths were compared for two concrete grades (C20/25 and C25/30). The study shown that near the well-known possibilities of improving mechanical strengths of cement concrete by increasing cement dosage and strength, by using crushed aggregates and by reducing the water/cement ratio, there are other methods in which less cement is used by replacing it with different wastes or by adding fiber.

Examining the Effects of READ 180 with Sixth Grade Students in a Southwest United States School District Based on a Formative Assessment--Measures of Academic Progress--and Its Impact on Leadership Decisions

ERIC Educational Resources Information Center

Davis, Daniel A.

2012-01-01

An achievement gap in reading existed in a Southwest United States school district with Hispanic, economically disadvantaged, English Language Learners (ELLs), and special education sixth grade students based on Measures of Academic Progress data. This study investigated the effectiveness of the "READ 180" reading intervention program…

The Impact of Online and Traditional Homework on the Attitudes, Achievement, and Learning Styles of Sixth Grade Language Arts Students

ERIC Educational Resources Information Center

Nordstrom, Hope McGee

2012-01-01

The purpose of this study was to examine the use of online homework as one way to bridge the gap between how students live and the diverse ways they learn by focusing on the attitudes, academic achievement, and learning styles of sixth grade language arts students. Students in the treatment group completed online homework, while the control group…

Upping the Ante of Text Complexity in the Common Core State Standards: Examining Its Potential Impact on Young Readers

ERIC Educational Resources Information Center

Hiebert, Elfrieda H.; Mesmer, Heidi Anne E.

2013-01-01

The Common Core Standards for the English Language Arts (CCSS) provide explicit guidelines matching grade-level bands (e.g., 2-3, 4-5) with targeted text complexity levels. The CCSS staircase accelerates text expectations for students across Grades 2-12 in order to close a gap in the complexity of texts typically used in high school and those of…

Closing the social-class achievement gap: a difference-education intervention improves first-generation students' academic performance and all students' college transition.

PubMed

Stephens, Nicole M; Hamedani, MarYam G; Destin, Mesmin

2014-04-01

College students who do not have parents with 4-year degrees (first-generation students) earn lower grades and encounter more obstacles to success than do students who have at least one parent with a 4-year degree (continuing-generation students). In the study reported here, we tested a novel intervention designed to reduce this social-class achievement gap with a randomized controlled trial (N = 168). Using senior college students' real-life stories, we conducted a difference-education intervention with incoming students about how their diverse backgrounds can shape what they experience in college. Compared with a standard intervention that provided similar stories of college adjustment without highlighting students' different backgrounds, the difference-education intervention eliminated the social-class achievement gap by increasing first-generation students' tendency to seek out college resources (e.g., meeting with professors) and, in turn, improving their end-of-year grade point averages. The difference-education intervention also improved the college transition for all students on numerous psychosocial outcomes (e.g., mental health and engagement).

Daily online testing in large classes: boosting college performance while reducing achievement gaps.

PubMed

Pennebaker, James W; Gosling, Samuel D; Ferrell, Jason D

2013-01-01

An in-class computer-based system, that included daily online testing, was introduced to two large university classes. We examined subsequent improvements in academic performance and reductions in the achievement gaps between lower- and upper-middle class students in academic performance. Students (N = 901) brought laptop computers to classes and took daily quizzes that provided immediate and personalized feedback. Student performance was compared with the same data for traditional classes taught previously by the same instructors (N = 935). Exam performance was approximately half a letter grade above previous semesters, based on comparisons of identical questions asked from earlier years. Students in the experimental classes performed better in other classes, both in the semester they took the course and in subsequent semester classes. The new system resulted in a 50% reduction in the achievement gap as measured by grades among students of different social classes. These findings suggest that frequent consequential quizzing should be used routinely in large lecture courses to improve performance in class and in other concurrent and subsequent courses.

Recursive processes in self-affirmation: intervening to close the minority achievement gap.

PubMed

Cohen, Geoffrey L; Garcia, Julio; Purdie-Vaughns, Valerie; Apfel, Nancy; Brzustoski, Patricia

2009-04-17

A 2-year follow-up of a randomized field experiment previously reported in Science is presented. A subtle intervention to lessen minority students' psychological threat related to being negatively stereotyped in school was tested in an experiment conducted three times with three independent cohorts (N = 133, 149, and 134). The intervention, a series of brief but structured writing assignments focusing students on a self-affirming value, reduced the racial achievement gap. Over 2 years, the grade point average (GPA) of African Americans was, on average, raised by 0.24 grade points. Low-achieving African Americans were particularly benefited. Their GPA improved, on average, 0.41 points, and their rate of remediation or grade repetition was less (5% versus 18%). Additionally, treated students' self-perceptions showed long-term benefits. Findings suggest that because initial psychological states and performance determine later outcomes by providing a baseline and initial trajectory for a recursive process, apparently small but early alterations in trajectory can have long-term effects. Implications for psychological theory and educational practice are discussed.

European Community emission inventory report 1990-2007 : under the UNECE Convention on Long-range Transboundary Air Pollution (LRTAP)

DOT National Transportation Integrated Search

2009-08-01

The main air pollutant emission trends in the period 19902007 for NOX, CO, NMVOCs, SOX, NH3, PM10 and PM2.5 by country, and aggregated for the EU-27 are described in this report. Due to various gaps in the underlying data reported by Member States...

Approaching Gender Equity in Academic Chemistry: Lessons Learned from Successful Female Chemists in the UK

ERIC Educational Resources Information Center

Miller-Friedmann, Jaimie; Childs, Ann; Hillier, Judith

2018-01-01

The internationally acknowledged gender gap in science continues to be an unrelenting concern to science educators; aggregate data in the UK show that both recruitment and retention of women in academic science remain relatively low. Most published research focuses on women in the broad field of science, generates correlations or predictions, or…

Subtyping of Children with Developmental Dyslexia via Bootstrap Aggregated Clustering and the Gap Statistic: Comparison with the Double-Deficit Hypothesis

ERIC Educational Resources Information Center

King, Wayne M.; Giess, Sally A.; Lombardino, Linda J.

2007-01-01

Background: The marked degree of heterogeneity in persons with developmental dyslexia has motivated the investigation of possible subtypes. Attempts have proceeded both from theoretical models of reading and the application of unsupervised learning (clustering) methods. Previous cluster analyses of data obtained from persons with reading…

A high-resolution bioclimate map of the world: a unifying framework for global biodiversity research and monitoring

USGS Publications Warehouse

Metzger, Marc J.; Bunce, Robert G.H.; Jongman, Rob H.G.; Sayre, Roger G.; Trabucco, Antonio; Zomer, Robert

2013-01-01

Main conclusions: The GEnS provides a robust spatial analytical framework for the aggregation of local observations, identification of gaps in current monitoring efforts and systematic design of complementary and new monitoring and research. The dataset is available for non-commercial use through the GEO portal (http://www.geoportal.org).

Karaoke Night at the Tower of Babel: The Cacophonous Discourse of School Reform

ERIC Educational Resources Information Center

Seidel, Steve

2014-01-01

Written for the general public, this article unpacks the "dialogue gap" in education and raises concerns about what can happen when groups dependent on one another are not talking. Part of the problem involves a matter of scale; policymakers rarely talk about children as individuals as opposed to as aggregates. The larger policy context…

Comparison of different objective functions for parameterization of simple respiration models

Treesearch

M.T. van Wijk; B. van Putten; D.Y. Hollinger; A.D. Richardson

2008-01-01

The eddy covariance measurements of carbon dioxide fluxes collected around the world offer a rich source for detailed data analysis. Simple, aggregated models are attractive tools for gap filling, budget calculation, and upscaling in space and time. Key in the application of these models is their parameterization and a robust estimate of the uncertainty and reliability...

Structure and dynamics in self-organized C60 fullerenes.

PubMed

Patnaik, Archita

2007-01-01

This manuscript on 'structure and dynamics in self-organized C60 fullerenes' has three sections dealing with: (A) pristine C60 aggregate structure and geometry in solvents of varying dielectric constant. Here, using positronium (Ps) as a fundamental probe which maps changes in the local electron density of the microenvironment, the onset concentration for stable C60 aggregate formation and its phase behavior is deduced from the specific interactions of the Ps atom with the surrounding. (B) A novel methanofullerene dyad, based on a hydrophobic (acceptor C60 moiety)-hydrophilic (bridge with benzene and ester functionalities)-hydrophobic (donor didodecyloxybenzene) network is chosen for investigation of characteristic self-assembly it undergoes leading to supramolecular aggregates. The pi-electronic amphiphile, necessitating a critical dielectric constant epsilon > or = 30 in binary THF-water mixtures, dictated the formation of bilayer vesicles as precursors for spherical fractal aggregates upon complete dyad extraction into a more polar water phase. (C) While the molecular orientation is dependent on the packing density, the ordering of the molecular arrangement, indispensable for self-assembly depends on the balance between the structures demanded by inter-molecular and molecule-substrate interactions. The molecular orientation in a monolayer affects the orientation in a multilayer, formed on the monolayer, suggesting the possibility of the latter to act as a template for controlling the structure of the three dimensionally grown self-assembled molecular aggregation. A systematic study on the electronic structure and orientation associated with C60 functionalized aminothiol self-assembled monolayers on Au(111) surface is presented using surface sensitive Ultra-Violet Photoelectron Spectroscopy (UPS) and C-K edge Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. The results revealed drastic modifications to d-band structure of Au(111) and the electronic structure was found sensitive towards the S-Au interface and the C60 end functional moiety with formation of localized sigma-(S-Au) and sigma(N-C) bonds, respectively. Upon binding C60 to the amine-terminated alkanethiol SAM, a drastically reduced HOMO-LUMO gap of 2.7 eV as compared to a large electronic gap of approximately 8 eV in alkanethiols enables the SAM to be a potential electron transport medium.

Analyzing phorbol ester effects on gap junctional communication: a dramatic inhibition of assembly

PubMed Central

1994-01-01

The effect of 12-O-tetradeconylphorbol-13-acetate (TPA) on gap junction assembly between Novikoff hepatoma cells was examined. Cells were dissociated with EDTA to single cells and then reaggregated to form new junctions. When TPA (25 nM) was added to the cells at the onset of the 60-min reaggregation, dye transfer was detected at only 0.6% of the cell-cell interfaces compared to 72% for the untreated control and 74% for 4-alpha TPA, an inactive isomer of TPA. Freeze-fracture electron microscopy of reaggregated control cells showed interfaces containing an average of more than 600 aggregated intramembranous gap junction particles, while TPA-treated cells had no gap junctions. However, Lucifer yellow dye transfer between nondissociated cells via gap junctions was unaffected by 60 min of TPA treatment. Therefore, TPA dramatically inhibited gap junction assembly but did not alter channel gating nor enhance disassembly of preexisting gap junction structures. Short term TPA treatment (< 30 min) increased phosphorylation of the gap junction protein molecular weight of 43,000 (Cx43), but did not change the cellular level of Cx43. Cell surface biotinylation experiments suggested that TPA did not substantially reduce the plasma membrane concentration of Cx43. Therefore, the simple presence of Cx43 in the plasma membrane is not sufficient for gap junction assembly, and protein kinase C probably exerts an effect on assembly of gap junctions at the plasma membrane level. PMID:7806568

Structural, Optical, and Photocatalytic Properties of Quasi-One-Dimensional Nanocrystalline ZnO, ZnOC:nC Composites, and C-doped ZnO

NASA Astrophysics Data System (ADS)

Shalaeva, E. V.; Gyrdasova, O. I.; Krasilnikov, V. N.; Melkozerova, M. A.; Baklanova, I. V.; Buldakova, L. Yu.

Various thermolysis rotes of zinc glicolate complexes are considered for the synthesis of quasi-one-dimensional nanostructured aggregates ZnO and Zn-O-C used as photocatalysts. Structural features of quasi-one-dimensional aggregates Zn-O-C and ZnO are investigated in detail. Transmission electron microscopy, Raman spectroscopy, and electron paramagnetic resonance spectroscopy methods demonstrate that the aggregates Zn-O-C have either composite structure (ZnO crystallites in amorphous carbon matrix) or a C-doped ZnO single-phase structure depending on heat treatment conditions, and that all the aggregates exhibit as a rule a tubular morphology, a nanocrystalline structure with a high specific surface area, and a high concentration of singly charged oxygen vacancies. The mechanism of the nanocrystalline structure formation is discussed and the effect of thermolysis condition on the formation of the textured structure of aggregates is investigated. The results of examination of the photocatalytic and optical absorption properties of the synthesized aggregates are presented. The photocatalytic activity for the hydroquinone oxidation reaction under ultraviolet and visible light increases in the series: the reference ZnO powder, quasi-one-dimensional ZnO, quasi-one-dimensional aggregates C-doped ZnO, and this tendency correlates with the reduction of the optical gap width. As a result of our studies, we have arrived at an important conclusion that thermal treatment of ZnO:nC composites allows a C-doped ZnO with high catalytic activity. This increasing photoactivity of C-doped ZnO aggregates is attributed to the optimal specific surface area and electron-energy spectrum restructuring to be produced owing to the presence of singly charged oxygen vacancies and carbon dissolved in the ZnO lattice.

Application of Replica Technique and SEM in Accuracy Measurement of Ceramic Crowns

NASA Astrophysics Data System (ADS)

Trifkovic, B.; Budak, I.; Todorovic, A.; Hodolic, J.; Puskar, T.; Jevremovic, D.; Vukelic, D.

2012-01-01

The paper presents a comparative study of the measuring values of the marginal gap related to the ceramic crowns made by dental CAD/CAM system using the replica technique and SEM. The study was conducted using three experimental groups, which consisted of ceramic crowns manufactured by the Cerec CAD/CAM system. The scanning procedure was carried out using three specialized dental 3D digitization systems from the Cerec family - two types of extraoral optical scanning systems and an intraoral optical scanner. Measurements of the marginal gap were carried out using the replica technique and SEM. The comparison of aggregate values of the marginal gap using the replica technique showed a statistically significant difference between the systems. The measured values of marginal gaps of ceramic crowns using the replica technique were significantly lower compared to those measured by SEM. The results indicate that the choice of technique for measuring the accuracy of ceramic crowns influences the final results of investigation.

The Effect of Sex-Dependent Norms on Aggregated Reading and Mathematics Test Scores.

ERIC Educational Resources Information Center

Gramenz, Gary W.; And Others

1986-01-01

Differences between school reading and mathematics means, rank orderings, and change scores obtained from total-group and sex-dependent norms were examined for students in grades 2 through 9 in a Florida school district. A preliminary study investigated sex-related differences between verbal and quantitative performance of boys and girls on seven…

Social Prominence and the Heterogeneity of Rejected Status in Late Elementary School

ERIC Educational Resources Information Center

Farmer, Thomas W.; Hall, Cristin M.; Leung, Man-Chi; Estell, David B.; Brooks, Debra

2011-01-01

The heterogeneity of peer rejection was examined as a function of social prominence in fifth grade classrooms. From an overall sample of 3,891 (1,931 girls) students, 721 youth (424 boys) were identified with rejected status. Social prominence was determined from the aggregation of peer nominations for "leader", "athletic", "cool", and "popular".…

Asphalt Concrete for Cold Regions, A Comparative Laboratory Study and Analysis of Mixtures Containing Soft and Hard Grades of Asphalt Cement,

DTIC Science & Technology

1980-01-01

Justification January 1980 BY Distribution Availabilit CodesIAvail an~d/or Dist special Prepa red for DIRECTORATE OF MILITARY PROGRAMS OFFICE, CHIEF OF...of water on the resilient modulus of asphalt treated mixes. Proecedinfp 4. Asphalt concrete mixes using the Tilton aggregates Association of Asphalt

7 CFR 51.1220 - Leaf or limb rub injury.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf or limb rub injury. 51.1220 Section 51.1220... STANDARDS) United States Standards for Grades of Peaches Definitions § 51.1220 Leaf or limb rub injury. “Leaf or limb rub injury” means that the scarring is not smooth, not light colored, or aggregates more...

7 CFR 51.1220 - Leaf or limb rub injury.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Leaf or limb rub injury. 51.1220 Section 51.1220... STANDARDS) United States Standards for Grades of Peaches Definitions § 51.1220 Leaf or limb rub injury. “Leaf or limb rub injury” means that the scarring is not smooth, not light colored, or aggregates more...

7 CFR 51.1220 - Leaf or limb rub injury.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Leaf or limb rub injury. 51.1220 Section 51.1220... STANDARDS) United States Standards for Grades of Peaches Definitions § 51.1220 Leaf or limb rub injury. “Leaf or limb rub injury” means that the scarring is not smooth, not light colored, or aggregates more...

Additional Evidence on the Relationship between Class Size and Student Performance

ERIC Educational Resources Information Center

Arias, J. J.; Walker, Douglas M.

2004-01-01

Much of the economic education literature suggests that the principles of economics class size does not significantly affect student performance. However, study methods have varied in terms of the aggregation level (student or class), the measure of performance (TUCE or course letter grade), and the class size measure (e.g., students who completed…

Evaluation of Different Mineral Filler Aggregates for Asphalt Mixtures

NASA Astrophysics Data System (ADS)

Wasilewska, Marta; Małaszkiewicz, Dorota; Ignatiuk, Natalia

2017-10-01

Mineral filler aggregates play an important role in asphalt mixtures because they fill voids in paving mix and improve the cohesion of asphalt binder. Limestone powder containing over 90% of CaCO3 is the most frequently used type of filler. Waste material from the production of coarse aggregate can be successfully used as a mineral filler aggregate for hot asphalt concrete mixtures as the limestone powder replacement. This paper presents the experimental results of selected properties of filler aggregates which were obtained from rocks with different mineral composition and origin. Five types of rocks were used as a source of the mineral filler aggregate: granite, gabbro, trachybasalt, quartz sandstone and rocks from postglacial deposits. Limestone filler was used in this study as the reference material. The following tests were performed: grading (air jet sieving), quality of fines according to methylene blue test, water content by drying in a ventilated oven, particle density using pyknometer method, Delta ring and ball test, Bitumen Number, fineness determined as Blaine specific surface area. Mineral filler aggregates showed significant differences when they were mixed with bitumen and stiffening effect in Delta ring and ball test was evaluated. The highest values were achieved when gabbro and granite fillers were used. Additionally, Scanning Electron Microscopy (SEM) analysis of grain shape and size was carried out. Significant differences in grain size and shape were observed. The highest non-homogeneity in size was determined for quartz sandstone, gabbro and granite filler. Their Blaine specific surface area was lower than 2800 cm2/g, while for limestone and postglacial fillers with regular and round grains it exceeded 3000 cm2/g. All examined mineral filler aggregates met requirements of Polish National Specification WT-1: 2014 and could be used in asphalt mixtures.

Heparin Assisted Photochemical Synthesis of Gold Nanoparticles and Their Performance as SERS Substrates

PubMed Central

Rodríguez-Torres, Maria del Pilar; Díaz-Torres, Luis Armando; Romero-Servin, Sergio

2014-01-01

Reactive and pharmaceutical-grade heparins were used as biologically compatible reducing and stabilizing agents to photochemically synthesize colloidal gold nanoparticles. Aggregates and anisotropic shapes were obtained photochemically under UV black-light lamp irradiation (λ = 366 nm). Heparin-functionalized gold nanoparticles were characterized by Scanning Electron Microscopy and UV-Vis spectroscopy. The negatively charged colloids were used for the Surface Enhanced Raman Spectroscopy (SERS) analysis of differently charged analytes (dyes). Measurements of pH were taken to inspect how the acidity of the medium affects the colloid-analyte interaction. SERS spectra were taken by mixing the dyes and the colloidal solutions without further functionalization or addition of any aggregating agent. PMID:25342319

Contribution of Road Grade to the Energy Use of Modern Automobiles Across Large Datasets of Real-World Drive Cycles: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, E.; Burton, E.; Duran, A.

Understanding the real-world power demand of modern automobiles is of critical importance to engineers using modeling and simulation to inform the intelligent design of increasingly efficient powertrains. Increased use of global positioning system (GPS) devices has made large scale data collection of vehicle speed (and associated power demand) a reality. While the availability of real-world GPS data has improved the industry's understanding of in-use vehicle power demand, relatively little attention has been paid to the incremental power requirements imposed by road grade. This analysis quantifies the incremental efficiency impacts of real-world road grade by appending high fidelity elevation profiles tomore » GPS speed traces and performing a large simulation study. Employing a large real-world dataset from the National Renewable Energy Laboratory's Transportation Secure Data Center, vehicle powertrain simulations are performed with and without road grade under five vehicle models. Aggregate results of this study suggest that road grade could be responsible for 1% to 3% of fuel use in light-duty automobiles.« less

Use of an audience response system (ARS) in a dual-campus classroom environment.

PubMed

Medina, Melissa S; Medina, Patrick J; Wanzer, Donald S; Wilson, Jane E; Er, Nelson; Britton, Mark L

2008-04-15

To implement an audience response system in a dual-campus classroom that aggregated data during graded (attendance and quizzes) and non-graded classroom activities (formative quizzes, case discussions, examination reviews, and team activities) and explore its strengths, weaknesses, and impact on active learning. After extensive research, an appropriate audience response system was selected and implemented in a dual-classroom setting for a third-year required PharmD course. Students were assigned a clicker and training and policies regarding clicker use were reviewed. Activities involving clicker use were carefully planned to simultaneously engage students in both classrooms in real time. Focus groups were conducted with students to gather outcomes data. Students and faculty members felt that the immediate feedback the automated response system (ARS) provided was most beneficial during non-graded activities. Student anxiety increased with use of ARS during graded activities due to fears regarding technology failure, user error, and academic integrity. ARS is a viable tool for increasing active learning in a doctor of pharmacy (PharmD) program, especially when used for non-graded class activities. Faculty members should proceed cautiously with using ARS for graded classroom activities and develop detailed and documented policies for ARS use.

Preparation and measurement methods for studying nanoparticle aggregate surface chemistry.

PubMed

Szakal, Christopher; McCarthy, James A; Ugelow, Melissa S; Konicek, Andrew R; Louis, Kacie; Yezer, Benjamin; Herzing, Andrew A; Hamers, Robert J; Holbrook, R David

2012-07-01

Despite best efforts at controlling nanoparticle (NP) surface chemistries, the environment surrounding nanomaterials is always changing and can impart a permanent chemical memory. We present a set of preparation and measurement methods to be used as the foundation for studying the surface chemical memory of engineered NP aggregates. We attempt to bridge the gap between controlled lab studies and real-world NP samples, specifically TiO(2), by using well-characterized and consistently synthesized NPs, controllably producing NP aggregates with precision drop-on-demand inkjet printing for subsequent chemical measurements, monitoring the physical morphology of the NP aggregate depositions with scanning electron microscopy (SEM), acquiring "surface-to-bulk" mass spectra of the NP aggregate surfaces with time-of-flight secondary ion mass spectrometry (ToF-SIMS), and developing a data analysis scheme to interpret chemical signatures more accurately from thousands of data files. We present differences in mass spectral peak ratios for bare TiO(2) NPs compared to NPs mixed separately with natural organic matter (NOM) or pond water. The results suggest that subtle changes in the local environment can alter the surface chemistry of TiO(2) NPs, as monitored by Ti(+)/TiO(+) and Ti(+)/C(3)H(5)(+) peak ratios. The subtle changes in the absolute surface chemistry of NP aggregates vs. that of the subsurface are explored. It is envisioned that the methods developed herein can be adapted for monitoring the surface chemistries of a variety of engineered NPs obtained from diverse natural environments.

Aggregation behavior of fullerenes in aqueous solutions: a capillary electrophoresis and asymmetric flow field-flow fractionation study.

PubMed

Astefanei, Alina; Núñez, Oscar; Galceran, Maria Teresa; Kok, Wim Th; Schoenmakers, Peter J

2015-10-01

In this work, the electrophoretic behavior of hydrophobic fullerenes [buckminsterfullerene (C60), C70, and N-methyl-fulleropyrrolidine (C60-pyrr)] and water-soluble fullerenes [fullerol (C60(OH)24); polyhydroxy small gap fullerene, hydrated (C120(OH)30); C60 pyrrolidine tris acid (C60-pyrr tris acid); and (1,2-methanofullerene C60)-61-carboxylic acid (C60CHCOOH)] in micellar electrokinetic capillary chromatography (MECC) was evaluated. The aggregation behavior of the water-soluble compounds in MECC at different buffer and sodium dodecyl sulfate (SDS) concentrations and pH values of the background electrolyte (BGE) was studied by monitoring the changes observed in the electrophoretic pattern of the peaks. Broad and distorted peaks that can be attributed to fullerene aggregation were obtained in MECC which became narrower and more symmetric by working at low buffer and SDS concentrations (below the critical micelle concentration, capillary zone electrophoresis (CZE) conditions). For the characterization of the suspected aggregates formed (size and shape), asymmetrical flow field-flow fractionation (AF4) and transmission electron microscopy (TEM) were used. The results showed that the increase in the buffer concentration promoted the aggregation of the particles, while the presence of SDS micelles revealed multiple peaks corresponding to particles of different aggregation degrees. Furthermore, MECC has been applied for the first time for the analysis of C60 in two different cosmetic products (i.e., anti-aging serum and facial mask).

Gap junctions modulate glioma invasion by direct transfer of microRNA.

PubMed

Hong, Xiaoting; Sin, Wun Chey; Harris, Andrew L; Naus, Christian C

2015-06-20

The invasiveness of high-grade glioma is the primary reason for poor survival following treatment. Interaction between glioma cells and surrounding astrocytes are crucial to invasion. We investigated the role of gap junction mediated miRNA transfer in this context. By manipulating gap junctions with a gap junction inhibitor, siRNAs, and a dominant negative connexin mutant, we showed that functional glioma-glioma gap junctions suppress glioma invasion while glioma-astrocyte and astrocyte-astrocyte gap junctions promote it in an in vitro transwell invasion assay. After demonstrating that glioma-astrocyte gap junctions are permeable to microRNA, we compared the microRNA profiles of astrocytes before and after co-culture with glioma cells, identifying specific microRNAs as candidates for transfer through gap junctions from glioma cells to astrocytes. Further analysis showed that transfer of miR-5096 from glioma cells to astrocytes is through gap junctions; this transfer is responsible, in part, for the pro-invasive effect. Our results establish a role for glioma-astrocyte gap junction mediated microRNA signaling in modulation of glioma invasive behavior, and that gap junction coupling among astrocytes magnifies the pro-invasive signaling. Our findings reveal the potential for therapeutic interventions based on abolishing alteration of stromal cells by tumor cells via manipulation of microRNA and gap junction channel activity.

Gap junctions modulate glioma invasion by direct transfer of microRNA

PubMed Central

Hong, Xiaoting; Sin, Wun Chey; Harris, Andrew L.; Naus, Christian C.

2015-01-01

The invasiveness of high-grade glioma is the primary reason for poor survival following treatment. Interaction between glioma cells and surrounding astrocytes are crucial to invasion. We investigated the role of gap junction mediated miRNA transfer in this context. By manipulating gap junctions with a gap junction inhibitor, siRNAs, and a dominant negative connexin mutant, we showed that functional glioma-glioma gap junctions suppress glioma invasion while glioma-astrocyte and astrocyte-astrocyte gap junctions promote it in an in vitro transwell invasion assay. After demonstrating that glioma-astrocyte gap junctions are permeable to microRNA, we compared the microRNA profiles of astrocytes before and after co-culture with glioma cells, identifying specific microRNAs as candidates for transfer through gap junctions from glioma cells to astrocytes. Further analysis showed that transfer of miR-5096 from glioma cells to astrocytes is through gap junctions; this transfer is responsible, in part, for the pro-invasive effect. Our results establish a role for glioma-astrocyte gap junction mediated microRNA signaling in modulation of glioma invasive behavior, and that gap junction coupling among astrocytes magnifies the pro-invasive signaling. Our findings reveal the potential for therapeutic interventions based on abolishing alteration of stromal cells by tumor cells via manipulation of microRNA and gap junction channel activity. PMID:25978028

Canopy arthropod response to density and distribution of green trees retained after partial harvest.

Treesearch

Timothy D. Schowalter; Yanli Zhang; Robert A. Progar

2005-01-01

We measured canopy arthropod responses to six contrasting green-tree retention treatments at six locations (blocks) in western Oregon and Washington as part of the Demonstration of Ecosystem Management Options (DEMO) study. Treatments were 100% retention (uncut), 75% retention with three 1-ha harvested gaps, 40% dispersed retention, 40% aggregated retention with five 1...

Pendulum Swings in Educational Policymaking: The Effects of Organizational, School, Financial and Social Characteristics on Student Performance Outcomes in Michigan School Districts

ERIC Educational Resources Information Center

Dyson, Dana D.

2009-01-01

Reforms in American public education have not resolved the wide academic performance gap between students attending schools in poor, large, urban centers versus schools in wealthier areas. Aggregate performance outcomes on state achievement tests reveal that some school districts consistently outperform others, a few fluctuate over time but are…

Lorelle Mansfield, Ph.D. | NREL

Science.gov Websites

)Se2 (CIGS) thin films for photovoltaic applications. In particular, she is developing rapid two-step content, and band gap grading. While at NREL, she has also deposited CIGS on novel substrates using low

Secondary prevention of work-related disability in nonspecific low back pain: does problem-solving therapy help? A randomized clinical trial.

PubMed

van den Hout, Johanna H C; Vlaeyen, Johan W S; Heuts, Peter H T G; Zijlema, Johan H L; Wijnen, Joseph A G

2003-01-01

Given the individual and economic burden of chronic work disability in low back pain patients, there is a need for effective preventive interventions. The aim of the present study was to investigate whether problem-solving therapy had a supplemental value when added to behavioral graded activity, regarding days of sick leave and work status. Randomized controlled trial. Employees who were recently on sick leave as a result of nonspecific low back pain were referred to the rehabilitation center by general practitioner, occupational physician, or rehabilitation physician. Forty-five employees had been randomly assigned to the experimental treatment condition that included behavioral graded activity and problem-solving therapy (GAPS), and 39 employees had been randomly assigned to behavioral graded activity and group education (GAGE). Days of sick leave and work status. Data were retrieved from occupational health services. Data analyses showed that employees in the GAPS group had significantly fewer days of sick leave in the second half-year after the intervention. Moreover, work status was more favorable for employees in this condition, in that more employees had a 100% return-to-work and fewer patients ended up receiving disability pensions one year after the intervention. Sensitivity analyses confirmed these results. The addition of problem-solving therapy to behavioral graded activity had supplemental value in employees with nonspecific low back pain.

Measuring engagement in fourth to twelfth grade classrooms: the Classroom Engagement Inventory.

PubMed

Wang, Ze; Bergin, Christi; Bergin, David A

2014-12-01

Research on factors that may promote engagement is hampered by the absence of a measure of classroom-level engagement. Literature has suggested that engagement may have 3 dimensions--affective, behavioral, and cognitive. No existing engagement scales measure all 3 dimensions at the classroom level. The Classroom Engagement Inventory (CEI) was developed to fill this gap. In Study 1, exploratory and confirmatory factor analyses were conducted on data from 3,481 students from the 4th to 12th grade. The results suggested a 4-factor model of the CEI. Using these results, in Study 2 several items were revised and data were collected 1 year later from 4th to 12th grade students in the same school district as Study 1. Analyses were conducted on data from 3,560 students after data cleaning. A series of potential models was tested. The final results suggest a 5-factor 24-item CEI: (1) Affective Engagement, (2) Behavioral Engagement-Compliance, (3) Behavioral Engagement-Effortful Class Participation, (4) Cognitive Engagement, and (5) Disengagement. Results advance understanding of the construct of classroom engagement. The CEI fills a significant gap in measurement of engagement. The CEI is classroom level, measures multiple dimensions of engagement, uses self-report, is relatively short, and can be readily administered in classrooms from the 4th to 12th grade. PsycINFO Database Record (c) 2014 APA, all rights reserved.

AC-dielectrophoretic force assisted fabrication of conducting quantum dot aggregates in the electrical breakdown-induced CNT nanogap

NASA Astrophysics Data System (ADS)

Shim, Hyung Cheoul; Choi, Hyekyoung; Jeong, Sohee

2018-03-01

In this paper, we fabricated quantum dot (QD) aggregates at desired locations using dielectrophoretic (DEP) forces induced in the carbon nanotube (CNT) nanogap created by Joule heating-induced electrical breakdown. Nanogaps with a size of at least 20-30 nm can be effectively fabricated in the ambient condition, and fabrication yield can be monitored through in-situ electrical signal without post morphological analysis. The geometry of CNT electrodes with high aspect ratio as well as the gap size of the electrodes to a few tens of nanometers scale enabled the derivation of sufficiently high DEP forces that facilitate the trapping of QD in the CNT nanogap. Above all, we were able to fabricate a conducting crack-free QD aggregates by exchanging the ligands on the surface of the QDs in the presence of a DEP force and this approach showed the possibility of being applied as a QD based optoelectronic devices.

Graded junction termination extensions for electronic devices

NASA Technical Reports Server (NTRS)

Merrett, J. Neil (Inventor); Isaacs-Smith, Tamara (Inventor); Sheridan, David C. (Inventor); Williams, John R. (Inventor)

2006-01-01

A graded junction termination extension in a silicon carbide (SiC) semiconductor device and method of its fabrication using ion implementation techniques is provided for high power devices. The properties of silicon carbide (SiC) make this wide band gap semiconductor a promising material for high power devices. This potential is demonstrated in various devices such as p-n diodes, Schottky diodes, bipolar junction transistors, thyristors, etc. These devices require adequate and affordable termination techniques to reduce leakage current and increase breakdown voltage in order to maximize power handling capabilities. The graded junction termination extension disclosed is effective, self-aligned, and simplifies the implementation process.

Graded junction termination extensions for electronic devices

NASA Technical Reports Server (NTRS)

Merrett, J. Neil (Inventor); Isaacs-Smith, Tamara (Inventor); Sheridan, David C. (Inventor); Williams, John R. (Inventor)

2007-01-01

A graded junction termination extension in a silicon carbide (SiC) semiconductor device and method of its fabrication using ion implementation techniques is provided for high power devices. The properties of silicon carbide (SiC) make this wide band gap semiconductor a promising material for high power devices. This potential is demonstrated in various devices such as p-n diodes, Schottky diodes, bipolar junction transistors, thyristors, etc. These devices require adequate and affordable termination techniques to reduce leakage current and increase breakdown voltage in order to maximize power handling capabilities. The graded junction termination extension disclosed is effective, self-aligned, and simplifies the implementation process.

Unpacking Gender Differences in Students' Perceived Experiences in Introductory Physics

NASA Astrophysics Data System (ADS)

Kost, Lauren E.; Pollock, Steven J.; Finkelstein, Noah D.

2009-11-01

Prior research has shown, at our institution: 1) males outperform females on conceptual assessments (a gender gap), 2) the gender gap persists despite the use of research-based reforms, and 3) the gender gap is correlated with students' physics and mathematics background and prior attitudes and beliefs [Kost, et al. PRST-PER, 5, 010101]. Our follow-up work begins to explore how males and females experience the introductory course differently and how these differences relate to the gender gap. We gave a survey to students in the introductory course in which we investigated students' physics identity and self-efficacy. We find there are significant gender differences in each of these three areas, and further find that these measures are weakly correlated with student conceptual performance, and moderately correlated with course grade.

Predictors of gender achievement in physical science at the secondary level

NASA Astrophysics Data System (ADS)

Kozlenko, Brittany Hunter

This study used the 2009 National Assessment of Educational Progress (NAEP) science restricted data-set for twelfth graders. The NAEP data used in this research study is derived from a sample group of 11,100 twelfth grade students that represented a national population of over 3,000,000 twelfth grade students enrolled in science in the United States in 2009. The researcher chose the NAEP data set because it provided a national sample using uniform questions. This study investigated how the factors of socioeconomic status (SES), parental education level, mode of instruction, and affective disposition affect twelfth grade students' physical science achievement levels in school for the sample population and subgroups for gender. The factors mode of instruction and affective disposition were built through factor analysis based on available questions from the student surveys. All four factors were found to be significant predictors of physical science achievement for the sample population. NAEP exams are administered to a national sample that represents the population of American students enrolled in public and private schools. This was a non-experimental study that adds to the literature on factors that impact physical science for both genders. A gender gap is essentially nonexistent at the fourth grade level but appears at the eighth grade level in science based on information from NAEP (NCES, 1997). The results of the study can be used to make recommendation for policy change to diminish this gender gap in the future. Educators need to be using research to make instructional decisions; research-based instruction helps all students.

Bridging the Gaps.

ERIC Educational Resources Information Center

Netzer, Greg

1995-01-01

Discusses a model water quality monitoring project, Project Bridge, established to train minority girls about to enter eighth grade in scientific procedures followed by hands-on experimentation. Students spent a week monitoring water in an urban stream and analyzing results. (LZ)

Adding to the Education Debt: Depressive Symptoms Mediate the Association between Racial Discrimination and Academic Performance in African Americans

PubMed Central

English, Devin; Lambert, Sharon F.; Ialongo, Nicholas S.

2015-01-01

Although the United States faces a seemingly intractable divide between white and African American academic performance, there remains a dearth of longitudinal research investigating factors that work to maintain this gap. The present study examined whether racial discrimination predicted the academic performance of African American students through its effect on depressive symptoms. Participants were a community sample of African American adolescents (N = 495) attending urban public schools from grade 7 to grade 9 (Mage = 12.5). Structural equation modeling revealed that experienced racial discrimination predicted increases in depressive symptoms 1 year later, which, in turn, predicted decreases in academic performance the following year. These results suggest that racial discrimination continues to play a critical role in the academic performance of African American students and, as such, contributes to the maintenance of the race-based academic achievement gap in the United States. PMID:27425564

Slow Auger Relaxation in HgTe Colloidal Quantum Dots.

PubMed

Melnychuk, Christopher; Guyot-Sionnest, Philippe

2018-05-03

The biexciton lifetimes in HgTe colloidal quantum dots are measured as a function of particle size. Samples produced by two synthetic methods, leading to partially aggregated or well-dispersed particles, exhibit markedly different dynamics. The relaxation characteristics of partially aggregated HgTe inhibit reliable determinations of the Auger lifetime. In well-dispersed HgTe quantum dots, the biexciton lifetime increases approximately linearly with particle volume, confirming trends observed in other systems. The extracted Auger coefficient is three orders of magnitude smaller than that for bulk HgCdTe materials with similar energy gaps. We discuss these findings in the context of understanding Auger relaxation in quantum-confined systems and their relevance to mid-infrared optoelectronic devices based on HgTe colloidal quantum dots.

Alterations in gap junction connexin43/connexin45 ratio mediate a transition from quiescence to excitation in a mathematical model of the myometrium

PubMed Central

Sheldon, Rachel E.; Mashayamombe, Chipo; Shi, Shao-Qing; Garfield, Robert E.; Shmygol, Anatoly; Blanks, Andrew M.; van den Berg, Hugo A.

2014-01-01

The smooth muscle cells of the uterus contract in unison during delivery. These cells achieve coordinated activity via electrical connections called gap junctions which consist of aggregated connexin proteins such as connexin43 and connexin45. The density of gap junctions governs the excitability of the myometrium (among other factors). An increase in gap junction density occurs immediately prior to parturition. We extend a mathematical model of the myometrium by incorporating the voltage-dependence of gap junctions that has been demonstrated in the experimental literature. Two functional subtypes exist, corresponding to systems with predominantly connexin43 and predominantly connexin45, respectively. Our simulation results indicate that the gap junction protein connexin45 acts as a negative modulator of uterine excitability, and hence, activity. A network with a higher proportion of connexin45 relative to connexin43 is unable to excite every cell. Connexin45 has much more rapid gating kinetics than connexin43 which we show limits the maximum duration of a local burst of activity. We propose that this effect regulates the degree of synchronous excitation attained during a contraction. Our results support the hypothesis that as labour approaches, connexin45 is downregulated to allow action potentials to spread more readily through the myometrium. PMID:25401181

Fragmentation approach to the point-island model with hindered aggregation: Accessing the barrier energy

NASA Astrophysics Data System (ADS)

González, Diego Luis; Pimpinelli, Alberto; Einstein, T. L.

2017-07-01

We study the effect of hindered aggregation on the island formation process in a one- (1D) and two-dimensional (2D) point-island model for epitaxial growth with arbitrary critical nucleus size i . In our model, the attachment of monomers to preexisting islands is hindered by an additional attachment barrier, characterized by length la. For la=0 the islands behave as perfect sinks while for la→∞ they behave as reflecting boundaries. For intermediate values of la, the system exhibits a crossover between two different kinds of processes, diffusion-limited aggregation and attachment-limited aggregation. We calculate the growth exponents of the density of islands and monomers for the low coverage and aggregation regimes. The capture-zone (CZ) distributions are also calculated for different values of i and la. In order to obtain a good spatial description of the nucleation process, we propose a fragmentation model, which is based on an approximate description of nucleation inside of the gaps for 1D and the CZs for 2D. In both cases, the nucleation is described by using two different physically rooted probabilities, which are related with the microscopic parameters of the model (i and la). We test our analytical model with extensive numerical simulations and previously established results. The proposed model describes excellently the statistical behavior of the system for arbitrary values of la and i =1 , 2, and 3.

Investigating the Source of the Gender Gap in Introductory Physics

NASA Astrophysics Data System (ADS)

Kost, Lauren E.; Pollock, Steven J.; Finkelstein, Noah D.

2007-11-01

Our previous research showed that despite the use of interactive engagement (IE) techniques at our institution, the difference in performance between men and women on a conceptual learning survey persisted from pre to posttest. This paper reports on a three-part follow-up study that investigates what factors contribute to the gender gap. First, we analyze student grades in different components of the course and find that men and women's course grades are not significantly different (p>0.1), but men outscore women on exams and women outscore men on homework and participation. Second, we compare average posttest scores of men and women who score similarly on the pretest and find that there are no significant differences between men and women's average posttest scores. Finally, we analyze other factors in addition to the pretest score that could influence the posttest score and find that gender does not account for a meaningful portion of the variation in posttest scores when a measure of mathematics performance is included. These findings indicate that the gender gap exists in interactive physics classes, but may be due in large part to differences in preparation, background, and math skills as assessed by traditional survey instruments.

Changes in Student Populations and Average Test Scores of Dutch Primary Schools

ERIC Educational Resources Information Center

Luyten, Hans; de Wolf, Inge

2011-01-01

This article focuses on the relation between student population characteristics and average test scores per school in the final grade of primary education from a dynamic perspective. Aggregated data of over 5,000 Dutch primary schools covering a 6-year period were used to study the relation between changes in school populations and shifts in mean…

The Indirect Effect of Alcohol Use on GPA in First-Semester College Students: The Mediating Role of Academic Effort

ERIC Educational Resources Information Center

Conway, James M.; DiPlacido, Joanne

2015-01-01

This study focused on first-semester college students, investigating (a) indirect effects of aggregate alcohol use on grade point average (GPA) through academic effort (skipping class and time on schoolwork) and (b) daily effects of alcohol use on reduced effort. Eighty students reported daily alcohol use and academic effort (skipping class and…

Using Bayesian Learning to Classify College Algebra Students by Understanding in Real-Time

ERIC Educational Resources Information Center

Cousino, Andrew

2013-01-01

The goal of this work is to provide instructors with detailed information about their classes at each assignment during the term. The information is both on an individual level and at the aggregate level. We used the large number of grades, which are available online these days, along with data-mining techniques to build our models. This enabled…

Ultra-high aggregate bandwidth two-dimensional multiple-wavelength diode laser arrays

NASA Astrophysics Data System (ADS)

Chang-Hasnain, Connie

1993-12-01

Two-dimensional (2D) multi-wavelength vertical cavity surface emitting laser (VCSEL) arrays is promising for ultrahigh aggregate capacity optical networks. A 2D VCSEL array emitting 140 distinct wavelengths was reported by implementing a spatially graded layer in the VCSEL structure, which in turn creates a wavelength spread. Concentrtion was on epitaxial growth techniques to make reproducible and repeatable multi-wavelength VCSEL arrays. Our approach to fabricate the spatially graded layer involves creating a nonuniform substrate surface temperature across the wafer during the growth of the cavity spacer region using the fact that the molecular beam epitaxy growth of GaAs is highly sensitive to the substrate temperature. Growth is investigated with the use of a patterned spacer (either a Ga or Si substrate) placed in-between the substrate and its heater. The temperature distribution on such wafers is used to guide our experiments. A reflectivity measurement apparatus that is capable of mapping a 2 in. wafer with a 100 microns diameter resolution was built for diagnosing our wafers. In this first six-month report, our calculations, the various experimental results, and a discussion on future directions are presented.

Effect of temporal and spectral noise features on gap detection behavior by calling green treefrogs.

PubMed

Höbel, Gerlinde

2014-10-01

Communication plays a central role in the behavioral ecology of many animals, yet the background noise generated by large breeding aggregations may impair effective communication. A common behavioral strategy to ameliorate noise interference is gap detection, where signalers display primarily during lulls in the background noise. When attempting gap detection, signalers have to deal with the fact that the spacing and duration of silent gaps is often unpredictable, and that noise varies in its spectral composition and may thus vary in the degree in which it impacts communication. I conducted playback experiments to examine how male treefrogs deal with the problem that refraining from calling while waiting for a gap to appear limits a male's ability to attract females, yet producing calls during noise also interferes with effective sexual communication. I found that the temporal structure of noise (i.e., duration of noise and silent gap segments) had a stronger effect on male calling behavior than the spectral composition. Males placed calls predominantly during silent gaps and avoided call production during short, but not long, noise segments. This suggests that male treefrogs use a calling strategy that maximizes the production of calls without interference, yet allows for calling to persist if lulls in the background noise are infrequent. Copyright © 2014 Elsevier B.V. All rights reserved.

A longitudinal examination of the link between youth physical fitness and academic achievement.

PubMed

London, Rebecca A; Castrechini, Sebastian

2011-07-01

Childhood obesity has been linked with other persistent health problems, but research is just beginning to examine its relationship with academic performance. This article tracks students longitudinally to examine the ways student physical fitness and changes in fitness align with school performance. Using matched administrative data and individual growth modeling, we examine the relationship between academic achievement and overall physical fitness longitudinally from fourth to seventh and sixth to ninth grades for students in a California community. Comparing those who are persistently fit to those who are persistently unfit, we find disparities in both math and English language arts test scores. These academic disparities begin even before students begin fitness testing in fifth grade and are larger for girls and Latinos. Overall physical fitness is a better predictor of academic achievement than obesity as measured by body mass index. Socioeconomic status acts as a buffer for those who have poor physical fitness but strong academic performance. The findings indicate the presence of a physical fitness achievement gap that has consequences for potential students' future educational and health outcomes. This gap begins as early as fourth grade, which is before physical fitness testing begins in California. © 2011, American School Health Association.

Gap Junctions and Connexin Hemichannels Underpin Haemostasis and Thrombosis

PubMed Central

Vaiyapuri, Sakthivel; Jones, Chris I.; Sasikumar, Parvathy; Moraes, Leonardo A.; Munger, Stephanie J.; Wright, Joy R.; Ali, Marfoua S.; Sage, Tanya; Kaiser, William J.; Tucker, Katherine L.; Stain, Christopher J.; Bye, Alexander P.; Jones, Sarah; Oviedo-Orta, Ernesto; Simon, Alexander M.; Mahaut-Smith, Martyn P.; Gibbins, Jonathan M.

2012-01-01

Background Connexins are a widespread family of membrane proteins that assemble into hexameric hemichannels, also known as connexons. Connexons regulate membrane permeability in individual cells or couple between adjacent cells to form gap junctions and thereby provide a pathway for regulated intercellular communication. We have now examined the role of connexins in platelets, blood cells that circulate in isolation, but upon tissue injury adhere to each other and the vessel wall to prevent blood loss and facilitate wound repair. Methods and Results We report the presence of connexins in platelets, notably connexin37, and that the formation of gap junctions within platelet thrombi is required for the control of clot retraction. Inhibition of connexin function modulated a range of platelet functional responses prior to platelet-platelet contact, and reduced laser induced thrombosis in vivo in mice. Deletion of the Cx37 gene (Gja4) in transgenic mice reduced platelet aggregation, fibrinogen binding, granule secretion and clot retraction indicating an important role for Cx37 hemichannels and gap junctions in platelet thrombus function. Conclusions Together, these data demonstrate that platelet gap junctions and hemichannels underpin the control of haemostasis and thrombosis and represent potential therapeutic targets. PMID:22528526

Different behavioral patterns of success for men and women in an online introductory science course: Addressing the course grade gender gap

NASA Astrophysics Data System (ADS)

Mead, C.; Horodyskyj, L.; Buxner, S.; Semken, S. C.; Anbar, A. D.

2016-12-01

In this study, we explore how data provided by an online learning environment can provide fine-grained behavioral context for the performance gender gap commonly observed in introductory college science courses. Previous studies reported that women earn lower grades than men in such courses, often ascribed to reduced engagement and resilience driven by sociocultural causes, such as stereotype threat. This may be exacerbated in courses graded primarily based on high-stakes exams. Here, we use student data (n = 1121) from Habitable Worlds, an online laboratory science course, to identify behavioral differences between men and women. In Habitable Worlds, students earn points from 30 "trainings," which are scored on completion, and 30 "applications," which are scored on correctness. The lack of high-stakes cumulative exams represents a valuable contrast with typical science courses in which gender gaps have been reported. Our data indicate that a gender gap exists even for these low-stakes assessments. Results of a generalized linear model show that course success among women is much more strongly predicted by training scores than by application scores, while those factors have roughly equal predictive value among men. Predicted success among women is also modulated by the total number of attempts made on questions throughout the course, where more attempts implies lower success (holding other factors constant). This relationship is non-significant for men. Our interpretation of these model results is that obstacles such as stereotype threat represent a tax for women on effort and engagement, such that equivalent effort yields lesser success than for men. Thus, the women who do succeed differ sharply from lower performing women on indicators of effort. Future work should build on this result both as an indicator of conditions under which women are more likely to succeed and as a way to more quickly identify students who may struggle.

Value-added utilisation of recycled concrete in hot-mix asphalt.

PubMed

Wong, Yiik Diew; Sun, Darren Delai; Lai, Dickson

2007-01-01

The feasibility of partial substitution of granite aggregate in hot-mix asphalt (HMA) with waste concrete aggregate was investigated. Three hybrid HMA mixes incorporating substitutions of granite fillers/fines with 6%, 45% untreated, and 45% heat-treated concrete were evaluated by the Marshall mix design method; the optimum binder contents were found to be 5.3%, 6.5% and 7.0% of grade Pen 60/70 bitumen, respectively. All three hybrid mixes satisfied the Marshall criteria of the Singapore Land Transport Authority (LTA) W3B wearing course specification. The hybrid mix with 6% concrete fillers gave comparable resilient modulus and creep resistance as the conventional W3B mix, while hybrid mixes with higher concrete substitutions achieved better performance. X-ray diffraction (XRD) showed the distinct presence of free lime in the heat-treated concrete, while the scanning electron microscope (SEM) provided an in-depth perspective of the concrete grains in the HMA matrix. The results suggest feasible use of waste concrete as partial aggregate substitution in HMA.

State Test Score Trends through 2008-09, Part 4: Is Achievement Improving and Are Gaps Narrowing for Title I Students? Utah

ERIC Educational Resources Information Center

Center on Education Policy, 2011

2011-01-01

This paper profiles Utah's test score trends through 2008-09. In 2004, the mean scale score on the state 4th grade reading test was 167 for non-Title I students and 164 for Title I students. In 2009 the mean scale score in 4th grade reading was 168 for non-Title I students and 164 for Title I students. Between 2004 and 2009, the mean scale score…

State Test Score Trends through 2008-09, Part 4: Is Achievement Improving and Are Gaps Narrowing for Title I Students? Colorado

ERIC Educational Resources Information Center

Center on Education Policy, 2011

2011-01-01

This paper profiles Colorado's test score trends through 2008-09. In 2003, the mean scale score on the state 4th grade reading test was 598 for non-Title I students and 558 for Title I students. In 2009, the mean scale score in 4th grade reading was 599 for non-Title I students and 556 for Title I students. Between 2003 and 2009, the mean scale…

State Test Score Trends through 2008-09, Part 4: Is Achievement Improving and Are Gaps Narrowing for Title I Students? North Carolina

ERIC Educational Resources Information Center

Center on Education Policy, 2011

2011-01-01

This paper profiles North Carolina's test score trends through 2008-09. In 2006, the mean scale score on the state 4th grade math test was 351 for non-Title I students and 347 for Title I students. In 2009, the mean scale score in 4th grade math was 354 for non-Title I students and 350 for Title I students. Between 2006 and 2009, the mean scale…

State Test Score Trends through 2008-09, Part 4: Is Achievement Improving and Are Gaps Narrowing for Title I Students? Delaware

ERIC Educational Resources Information Center

Center on Education Policy, 2011

2011-01-01

This paper profiles Delaware's test score trends through 2008-09. In 2006, the mean scale score on the state 4th grade reading test was 474 for non-Title I students and 464 for Title I students. In 2009, the mean scale score in 4th grade reading was 478 for non-Title I students and 467 for Title I students. Between 2006 and 2009, the mean scale…

State Test Score Trends through 2008-09, Part 4: Is Achievement Improving and Are Gaps Narrowing for Title I Students? New Hampshire

ERIC Educational Resources Information Center

Center on Education Policy, 2011

2011-01-01

This paper profiles New Hampshire's test score trends through 2008-09. In 2006, the mean scale score on the state 4th grade reading test was 445 for non-Title I students and 438 for Title I students. In 2009, the mean scale score in 4th grade reading was 448 for non-Title I students and 441 for Title I students. Between 2006 and 2009, the mean…

State Test Score Trends through 2008-09, Part 4: Is Achievement Improving and Are Gaps Narrowing for Title I Students? Missouri

ERIC Educational Resources Information Center

Center on Education Policy, 2011

2011-01-01

This paper profiles Missouri's test score trends through 2008-09. In 2006, the mean scale score on the state 4th grade reading test was 661 for non-Title I students and 642 for Title I students. In 2009, the mean scale score in 4th grade reading was 661 for non-Title I students and 648 for Title I students. Between 2006 and 2009, there was no…

State Test Score Trends through 2008-09, Part 4: Is Achievement Improving and Are Gaps Narrowing for Title I Students? Kentucky

ERIC Educational Resources Information Center

Center on Education Policy, 2011

2011-01-01

This paper profiles Kentucky's test score trends through 2008-09. In 2007, the mean scale score on the state 4th grade reading test was 455 for non-Title I students and 451 for Title I students. In 2009, the mean scale score in 4th grade reading was 455 for non-Title I students and 451 for Title I students. Between 2007 and 2009, the mean scale…

Databases applicable to quantitative hazard/risk assessment-Towards a predictive systems toxicology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waters, Michael; Jackson, Marcus

2008-11-15

The Workshop on The Power of Aggregated Toxicity Data addressed the requirement for distributed databases to support quantitative hazard and risk assessment. The authors have conceived and constructed with federal support several databases that have been used in hazard identification and risk assessment. The first of these databases, the EPA Gene-Tox Database was developed for the EPA Office of Toxic Substances by the Oak Ridge National Laboratory, and is currently hosted by the National Library of Medicine. This public resource is based on the collaborative evaluation, by government, academia, and industry, of short-term tests for the detection of mutagens andmore » presumptive carcinogens. The two-phased evaluation process resulted in more than 50 peer-reviewed publications on test system performance and a qualitative database on thousands of chemicals. Subsequently, the graphic and quantitative EPA/IARC Genetic Activity Profile (GAP) Database was developed in collaboration with the International Agency for Research on Cancer (IARC). A chemical database driven by consideration of the lowest effective dose, GAP has served IARC for many years in support of hazard classification of potential human carcinogens. The Toxicological Activity Profile (TAP) prototype database was patterned after GAP and utilized acute, subchronic, and chronic data from the Office of Air Quality Planning and Standards. TAP demonstrated the flexibility of the GAP format for air toxics, water pollutants and other environmental agents. The GAP format was also applied to developmental toxicants and was modified to represent quantitative results from the rodent carcinogen bioassay. More recently, the authors have constructed: 1) the NIEHS Genetic Alterations in Cancer (GAC) Database which quantifies specific mutations found in cancers induced by environmental agents, and 2) the NIEHS Chemical Effects in Biological Systems (CEBS) Knowledgebase that integrates genomic and other biological data including dose-response studies in toxicology and pathology. Each of the public databases has been discussed in prior publications. They will be briefly described in the present report from the perspective of aggregating datasets to augment the data and information contained within them.« less

Pumice deposits of the Klamath Indian Reservation, Klamath County, Oregon

USGS Publications Warehouse

Walker, George Walton

1951-01-01

A large volume of pumice is widely distributed over the Klamath Indian Reservation in 'flow' and 'fall' deposits. The flow material on the Reservation is restricted to the area west of Klamath Marsh, and the fall material is thickest immediately southeast of the Marsh. Tests of the chemical and physical properties of the pumice indicate that the pumice is suitable, with some limitations, for use as an aggregate and as a low-grade abrasive. Preliminary examination also indicates that with proper processing it may have a potential use as pozzuolana. The pumice is similar to material now being marketed for lightweight aggregate in Oregon, but processing of the pumice is necessary to obtain a suitable size distribution of the particles.

Seismic vulnerability and damage of Italian historical centres: A case study in the Campania region

NASA Astrophysics Data System (ADS)

Formisano, Antonio; Chieffo, Nicola; Fabbrocino, Francesco; Landolfo, Raffaele

2017-07-01

The preservation of masonry buildings typical of Italian historical centres represents a very pressing dilemma founded on recovery need of the urban fabric original character. In the paper, based on a methodology developed by some of the Authors on building aggregates, the seismic vulnerability estimation of some masonry compounds in the heart of the town of San PotitoSannitico (Caserta, Italy) is presented and compared to the results achieved from applying the basic literature method for isolated constructions. Finally, the damage scenario of inspected buildings has been shown by highlighting clearly the influence of different positions of structural units on the damages that masonry aggregates suffer under different grade earthquakes, leading to individuate the most vulnerable buildings.

Dispersion relations of elastic waves in one-dimensional piezoelectric/piezomagnetic phononic crystal with functionally graded interlayers.

PubMed

Guo, Xiao; Wei, Peijun; Lan, Man; Li, Li

2016-08-01

The effects of functionally graded interlayers on dispersion relations of elastic waves in a one-dimensional piezoelectric/piezomagnetic phononic crystal are studied in this paper. First, the state transfer equation of the functionally graded interlayer is derived from the motion equation by the reduction of order (from second order to first order). The transfer matrix of the functionally graded interlayer is obtained by solving the state transfer equation with the spatial-varying coefficient. Based on the transfer matrixes of the piezoelectric slab, the piezomagnetic slab and the functionally graded interlayers, the total transfer matrix of a single cell is obtained. Further, the Bloch theorem is used to obtain the resultant dispersion equations of in-plane and anti-plane Bloch waves. The dispersion equations are solved numerically and the numerical results are shown graphically. Five kinds of profiles of functionally graded interlayers between a piezoelectric slab and a piezomagnetic slab are considered. It is shown that the functionally graded interlayers have evident influences on the dispersion curves and the band gaps. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of a framework to identify research gaps from systematic reviews.

PubMed

Robinson, Karen A; Saldanha, Ian J; McKoy, Naomi A

2011-12-01

Our objective was to develop a framework to identify research gaps from systematic reviews. We reviewed the practices of (1) evidence-based practice centers (EPCs), and (2) other organizations that conduct evidence syntheses. We developed and pilot tested a framework for identifying research gaps. Four (33%) EPCs and three (8%) other organizations reported using an explicit framework to determine research gaps. Variations of the PICO (population, intervention, comparison, outcomes) framework were most common. We developed a framework incorporating both the characterization of the gap using PICOS elements (also including setting) and the identification of the reason(s) why the gap exists as (1) insufficient or imprecise information, (2) biased information, (3) inconsistency or unknown consistency, and (4) not the right information. We mapped each of these reasons to concepts from three common evidence-grading systems. Our framework determines from systematic reviews where the current evidence falls short and why or how the evidence falls short. This explicit identification of research gaps will allow systematic reviews to maximally inform the types of questions that need to be addressed and the types of studies needed to address the research gaps. Copyright © 2011 Elsevier Inc. All rights reserved.

Comparison between Conventional MR Arthrograhphy and Abduction and External Rotation MR Arthrography in Revealing Tears of the Antero-Inferior Glenoid Labrum

PubMed Central

Choi, Jung-Ah; Suh, Sang-il; Kim, Baek Hyun; Cha, Sang Hoon; Lee, Ki Yeol; Lee, Chang Hee

2001-01-01

Objective To compare, in terms of their demonstration of tears of the anterior glenoid labrum, oblique axial MR arthrography obtained with the patient's shoulder in the abduction and external rotation (ABER) position, with conventional axial MR arthrography obtained with the patient's arm in the neutral position. Materials and Methods MR arthrography of the shoulder, including additional oblique axial sequences with the patient in the ABER position, was performed in 30 patients with a clinical history of recurrent anterior shoulder dislocation. The degree of anterior glenoid labral tear or defect was evaluated in both the conventional axial and the ABER position by two radiologists. Decisions were reached by consensus, and a three-point scale was used: grade 1=normal; grade 2=probable tear, diagnosed when subtle increased signal intensity in the labrum was apparent; grade 3=definite tear/defect, when a contrast material-filled gap between the labrum and the glenoid rim or deficient labrum was present. The scores for each imaging sequence were averaged and to compare conventional axial and ABER position scans, Student's t test was performed. Results In 21 (70%) of 30 patients, the same degree of anterior instability was revealed by both imaging sequences. Eight (27%) had a lower grade in the axial position than in the ABER position, while one (3%) had a higher grade in the axial position. Three whose axial scan was grade 1 showed only equivocal evidence of tearing, but their ABER-position scan, in which a contrast material-filled gap between the labrum and the glenoid rim was present, was grade 3. The average grade was 2.5 (SD=0.73) for axial scans and 2.8 (SD=0.46) for the ABER position. The difference between axial and ABER-position scans was statistically significant (p<0.05). Conclusion MR arthrography with the patient's shoulder in the ABER position is more efficient than conventional axial scanning in revealing the degree of tear or defect of the anterior glenoid labrum. When equivocal features are seen at conventional axial MR arthrography, oblique axial imaging in the ABER position is helpful. PMID:11754329

Comprehensive School Reform: Meta-Analytic Evidence of Black-White Achievement Gap Narrowing.

PubMed

Gorey, Kevin M

2009-12-30

This meta-analysis extends a previous review of the achievement effects of comprehensive school reform (CSR) programs (Borman, Hewes, Overman, & Brown, 2003). That meta-analysis observed significant effects of well endowed and well-researched programs, but it did not account for race/ethnicity. This article synthesizes 34 cohort or quasi-experimental outcomes of studies that incorporated the policy-critical characteristic of race/ethnicity. compared with matched traditional schools, the black-white achievement gap narrowed significantly more among students in CSR schools. In addition, the aggregate effects were large, substantially to completely eliminating the achievement gap between African American and non-Hispanic white students in elementary and middle schools. Title I policies before or after the No Child Left Behind Act of 2001 seem to have had essentially no impact on the black-white achievement gap. Curricular and testing mandates along with the threat of sanctions without concomitant resource supports seem to have failed. This study suggests that educational achievement inequities need not be America's destiny. It seems that they could be eliminated through concerted political will and ample resource commitments to evidence-based educational programs.

Feline vaccine-associated fibrosarcoma: morphologic distinctions.

PubMed

Couto, S S; Griffey, S M; Duarte, P C; Madewell, B R

2002-01-01

Forty-four primary feline vaccine-associated fibrosarcomas and 16 recurrences were examined histologically for detailed morphologic characterization with emphasis on tumor grade, presence of neoplastic multinucleated giant cells, presence and proportion of T and B lymphocytes within the tumor, and thin and intermediate filament contents of neoplastic and stromal cells. The microvascularity and proliferation rates of central and peripheral areas of the tumors were also quantified by computerized image analysis. For primary fibrosarcomas, 11 of 44 (25%) were grade I, 21 of 44 (47.7%) were grade II, and 12 of 44 (27.3%) were grade III. The recurrences followed a similar pattern: 4 of 16 (25%) were grade I, 8 of 16 (50%) were grade II, and 4 of 16 (25%) were grade III. A positive correlation was found between the presence of neoplastic multinucleated giant cells and tumor grade. These cells were present in 9 of 12 (75%) of grade III and none of the grade I tumors. Prominent peritumoral lymphoid aggregates or follicles were present in 59% of the tumors, and many contained high proportions of T lymphocytes, varying from 19 to 87%. All fibrosarcomas were immunoreactive for vimentin and 28 of 44 (64%) were reactive for alpha-smooth muscle actin. The actin-positive cells were either part of the tumor or formed a capsule around tumor nodules. The peripheral vascularity was significantly higher than the central vascular density but no difference was found in tumor cell proliferation rates between the two areas. Centrally located, fluid-filled micro- or macrocavitations were frequently observed in the large vaccine sarcomas and probably formed secondary to rapid tumor growth and central necrosis.

Use of an Audience Response System (ARS) in a Dual-Campus Classroom Environment

PubMed Central

Medina, Patrick J; Wanzer, Donald S; Wilson, Jane E; Er, Nelson; Britton, Mark L

2008-01-01

Objectives To implement an audience response system in a dual-campus classroom that aggregated data during graded (attendance and quizzes) and non-graded classroom activities (formative quizzes, case discussions, examination reviews, and team activities) and explore its strengths, weaknesses, and impact on active learning. Design After extensive research, an appropriate audience response system was selected and implemented in a dual-classroom setting for a third-year required PharmD course. Students were assigned a clicker and training and policies regarding clicker use were reviewed. Activities involving clicker use were carefully planned to simultaneously engage students in both classrooms in real time. Focus groups were conducted with students to gather outcomes data. Assessment Students and faculty members felt that the immediate feedback the automated response system (ARS) provided was most beneficial during non-graded activities. Student anxiety increased with use of ARS during graded activities due to fears regarding technology failure, user error, and academic integrity. Summary ARS is a viable tool for increasing active learning in a doctor of pharmacy (PharmD) program, especially when used for non-graded class activities. Faculty members should proceed cautiously with using ARS for graded classroom activities and develop detailed and documented policies for ARS use. PMID:18483604

Comparability of IQ Scores on Five Widely Used Intelligence Tests

ERIC Educational Resources Information Center

Hieronymus, A. N.; Stroud, James B.

1969-01-01

Attempts to fill research gap on testing by obtaining comparisons of deviation scores, at grade levels four, seven, and ten, from the California Test of Mental Maturity, Henmon-Nelson Tests, and Lorge-Thorndike Intelligence tests. Results tabulated. (CJ)

NovaChip pilot project : Route 5, Waterboro, Brownfield, & Fryeburg.

DOT National Transportation Integrated Search

2011-02-01

In July & August, 2010, MaineDOT conducted experimental applications of NovaChip on 16 miles : of highway in western Maine. Novachip is a proprietary pavement process that applies an ultrathin, : gap-graded, hot mix wearing course over a polymer rich...

Pneumatic Distension of Ventricular Mural Architecture Validated Histologically.

PubMed

Burg, M C; Lunkenheimer, P; Niederer, P; Brune, C; Redmann, K; Smerup, M; Spiegel, U; Becker, F; Maintz, D; Heindel, W; Anderson, R H

2016-11-01

Purpose: There are ongoing arguments as to how cardiomyocytes are aggregated together within the ventricular walls. We used pneumatic distension through the coronary arteries to exaggerate the gaps between the aggregated cardiomyocytes, analyzing the pattern revealed using computed tomography, and validating our findings by histology. Methods: We distended 10 porcine hearts, arresting 4 in diastole by infusion of cardioplegic solutions, and 4 in systole by injection of barium chloride. Mural architecture was revealed by computed tomography, measuring also the angulations of the long chains of cardiomyocytes. We prepared the remaining 2 hearts for histology by perfusion with formaldehyde. Results: Increasing pressures of pneumatic distension elongated the ventricular walls, but produced insignificant changes in mural thickness. The distension exaggerated the spaces between the aggregated cardiomyocytes, compartmenting the walls into epicardial, central, and endocardial regions, with a feathered arrangement of transitions between them. Marked variation was noted in the thicknesses of the parts in the different ventricular segments, with no visible anatomical boundaries between them. Measurements of angulations revealed intruding and extruding populations of cardiomyocytes that deviated from a surface-parallel alignment. Scrolling through the stacks of tomographic images revealed marked spiraling of the aggregated cardiomyocytes when traced from base to apex. Conclusion: Our findings call into question the current assumption that cardiomyocytes are uniformly aggregated together in a tangential fashion. There is marked heterogeneity in the architecture of the different ventricular segments, with the aggregated units never extending in a fully transmural fashion. Key Points: • Pneumographic computed tomography reveals an organized structure of the ventricular walls.• Aggregated cardiomyocytes form a structured continuum, with marked regional heterogeneity.• Global ventricular function results from antagonistic forces generated by aggregated cardiomyocytes. Citation Format: • Burg MC, Lunkenheimer P, Niederer P et al. Pneumatic Distension of Ventricular Mural Architecture Validated Histologically. Fortschr Röntgenstr 2016; 188: 1045 - 1053. © Georg Thieme Verlag KG Stuttgart · New York.

Factors affecting femoral rotational angle based on the posterior condylar axis in gap-based navigation-assisted total knee arthroplasty for valgus knee.

PubMed

Lee, Sung-Sahn; Lee, Yong-In; Kim, Dong-Uk; Lee, Dae-Hee; Moon, Young-Wan

2018-01-01

Achieving proper rotational alignment of the femoral component in total knee arthroplasty (TKA) for valgus knee is challenging because of lateral condylar hypoplasia and lateral cartilage erosion. Gap-based navigation-assisted TKA enables surgeons to determine the angle of femoral component rotation (FCR) based on the posterior condylar axis. This study evaluated the possible factors that affect the rotational alignment of the femoral component based on the posterior condylar axis. Between 2008 and 2016, 28 knees were enrolled. The dependent variable for this study was FCR based on the posterior condylar axis, which was obtained from the navigation system archives. Multiple regression analysis was conducted to identify factors that might predict FCR, including body mass index (BMI), Kellgren-Lawrence grade (K-L grade), lateral distal femoral angles obtained from the navigation system and radiographs (NaviLDFA, XrayLDFA), hip-knee-ankle (HKA) axis, lateral gap under varus stress (LGVS), medial gap under valgus stress (MGVS), and side-to-side difference (STSD, MGVS - LGVS). The mean FCR was 6.1° ± 2.0°. Of all the potentially predictive factors evaluated in this study, only NaviLDFA (β = -0.668) and XrayLDFA (β = -0.714) predicted significantly FCR. The LDFAs, as determined using radiographs and the navigation system, were both predictive of the rotational alignment of the femoral component based on the posterior condylar axis in gap-based TKA for valgus knee. A 1° increment with NaviLDFA led to a 0.668° decrement in FCR, and a 1° increment with XrayLDFA led to a 0.714° decrement. This suggests that symmetrical lateral condylar hypoplasia of the posterior and distal side occurs in lateral compartment end-stage osteoarthritis with valgus deformity.

Interface Modeling for Electro-Osmosis in Subgrade Structures

DTIC Science & Technology

2004-12-01

aggregate and different clays ( kaolinite , montmorillonite , limestone and quartz sands) created to simulate below grade structures. A direct current 30...Quartz Sand 100 Sieve Ca Montmorillonite Na Montmorillonite Kaolinite The test setup used a 0.45 water to cement ratio concrete cylinder... Kaolinite cell Figure 4. Measured pH for Concrete and Na Montmorillonite cell 4 Scaling occurred at the interface between the anode

Softwood lumber prices for evaluation of small diameter timber stands in the Intermountain West.

Treesearch

John T. Chmelik; Roger D. Fight; R. James Barbour

1999-01-01

This paper reports prices for aggregations of lumber grades that are representative of the quality and volume of lumber produced from small-diameter timber stands in the Intermountain West area encompassing Idaho and Montana and land east of the Cascade Mountain range in Oregon and Washington. Price data are reported for Douglas Fir1Larch, Hem1Fir, ponderosa pine, and...

Mineral Deposits and Mineral Potential of the China Lake Complex of the Naval Weapons Center, China Lake, California

DTIC Science & Technology

1983-12-01

Tucker and R. J. Sampson. 16 A field check of the area confirmed many of the physical aspects of the property as reported, but the tungsten grades...iron, mercury, perlite, pumice, aggregate, evaporites, travertine, and diatomite . Geothermal and water-producing strata were also investigated. The...Prospect ( Diatomite ) (N-1602) ..... ... 436 Evaporites .......... ....................... .436 Bonanza Group (N-1502) ..... ............... ... 436

Programming experience promotes higher STEM motivation among first-grade girls.

PubMed

Master, Allison; Cheryan, Sapna; Moscatelli, Adriana; Meltzoff, Andrew N

2017-08-01

The gender gap in science, technology, engineering, and math (STEM) engagement is large and persistent. This gap is significantly larger in technological fields such as computer science and engineering than in math and science. Gender gaps begin early; young girls report less interest and self-efficacy in technology compared with boys in elementary school. In the current study (N=96), we assessed 6-year-old children's stereotypes about STEM fields and tested an intervention to develop girls' STEM motivation despite these stereotypes. First-grade children held stereotypes that boys were better than girls at robotics and programming but did not hold these stereotypes about math and science. Girls with stronger stereotypes about robotics and programming reported lower interest and self-efficacy in these domains. We experimentally tested whether positive experience with programming robots would lead to greater interest and self-efficacy among girls despite these stereotypes. Children were randomly assigned either to a treatment group that was given experience in programming a robot using a smartphone or to control groups (no activity or other activity). Girls given programming experience reported higher technology interest and self-efficacy compared with girls without this experience and did not exhibit a significant gender gap relative to boys' interest and self-efficacy. These findings show that children's views mirror current American cultural messages about who excels at computer science and engineering and show the benefit of providing young girls with chances to experience technological activities. Copyright © 2017 Elsevier Inc. All rights reserved.

Cardiopulmonary monitoring in Thai ICUs (ICU-rESOURCE I Study).

PubMed

Chittawatanarat, Kaweesak; Wattanathum, Anan; Chaiwat, Onuma

2014-01-01

Cardiopulmonary monitoring (CPM) is rapidly progressing but data regarding CPM in Thai ICUs was unavailable. The objective of this study was to describe the situation, and gaps of CPM in Thai ICUs. Data were retrieved from the ICU-RESOURCE I study database survey CPM was divided into two aspects of device and measurement methods. These were categorized by device availability grading (AG), device availability per bed (DPB) and numeric frequency grading scale (FGS). Device availability was compared between academic and non-academic ICUs. Gap analysis of DPB and FGS was performed. Statistical significant difference was defined as p-value < 0.05. One hundred and fifty-five ICUs across Thailand participated in this study. Academic ICUs had significantly more devices available in new equipment with p < 0.05 (Vigilio, PiCCO, NICOM, esophageal pressure monitoring, transcutaneous PO2, electrical impedance tomography of lung) as well as measurement methods (stroke volume variation [SVV], pulse pressure variation [PPC], central venous oxygen saturation [ScvO2], lung mechanics). Most of new and higher technological devices had low density and few were available in all of Thai ICUs. However, in gap analysis, although these new devices and measurement techniques were available in ICUs, they were not frequently utilized. New technology devices of CPM had more availability in ACAD than in non-ACAD ICUs. Formal continuous training in new measurement methods should be established for reducing the availability and utilization gap (Thai Clinical Trial Registry: TCTR-201200005).

The data quality analyzer: A quality control program for seismic data

NASA Astrophysics Data System (ADS)

Ringler, A. T.; Hagerty, M. T.; Holland, J.; Gonzales, A.; Gee, L. S.; Edwards, J. D.; Wilson, D.; Baker, A. M.

2015-03-01

The U.S. Geological Survey's Albuquerque Seismological Laboratory (ASL) has several initiatives underway to enhance and track the quality of data produced from ASL seismic stations and to improve communication about data problems to the user community. The Data Quality Analyzer (DQA) is one such development and is designed to characterize seismic station data quality in a quantitative and automated manner. The DQA consists of a metric calculator, a PostgreSQL database, and a Web interface: The metric calculator, SEEDscan, is a Java application that reads and processes miniSEED data and generates metrics based on a configuration file. SEEDscan compares hashes of metadata and data to detect changes in either and performs subsequent recalculations as needed. This ensures that the metric values are up to date and accurate. SEEDscan can be run as a scheduled task or on demand. The PostgreSQL database acts as a central hub where metric values and limited station descriptions are stored at the channel level with one-day granularity. The Web interface dynamically loads station data from the database and allows the user to make requests for time periods of interest, review specific networks and stations, plot metrics as a function of time, and adjust the contribution of various metrics to the overall quality grade of the station. The quantification of data quality is based on the evaluation of various metrics (e.g., timing quality, daily noise levels relative to long-term noise models, and comparisons between broadband data and event synthetics). Users may select which metrics contribute to the assessment and those metrics are aggregated into a "grade" for each station. The DQA is being actively used for station diagnostics and evaluation based on the completed metrics (availability, gap count, timing quality, deviation from a global noise model, deviation from a station noise model, coherence between co-located sensors, and comparison between broadband data and synthetics for earthquakes) on stations in the Global Seismographic Network and Advanced National Seismic System.

Participation in Non-Formal Learning in EU-15 and EU-8 Countries: Demand and Supply Side Factors

ERIC Educational Resources Information Center

Roosmaa, Eve-Liis; Saar, Ellu

2012-01-01

The main purpose of this paper is to provide an in-depth analysis of participation in non-formal learning in different European Union member states. The paper also seeks to extend analysis of the training gap by pursuing the distinction between the supply and the demand for skills. We use aggregate data from the Adult Education Survey (Eurostat)…

Microplastics and Nanoplastics in Aquatic Environments: Aggregation, Deposition, and Enhanced Contaminant Transport.

PubMed

Alimi, Olubukola S; Farner Budarz, Jeffrey; Hernandez, Laura M; Tufenkji, Nathalie

2018-02-20

Plastic litter is widely acknowledged as a global environmental threat, and poor management and disposal lead to increasing levels in the environment. Of recent concern is the degradation of plastics from macro- to micro- and even to nanosized particles smaller than 100 nm in size. At the nanoscale, plastics are difficult to detect and can be transported in air, soil, and water compartments. While the impact of plastic debris on marine and fresh waters and organisms has been studied, the loads, transformations, transport, and fate of plastics in terrestrial and subsurface environments are largely overlooked. In this Critical Review, we first present estimated loads of plastics in different environmental compartments. We also provide a critical review of the current knowledge vis-à-vis nanoplastic (NP) and microplastic (MP) aggregation, deposition, and contaminant cotransport in the environment. Important factors that affect aggregation and deposition in natural subsurface environments are identified and critically analyzed. Factors affecting contaminant sorption onto plastic debris are discussed, and we show how polyethylene generally exhibits a greater sorption capacity than other plastic types. Finally, we highlight key knowledge gaps that need to be addressed to improve our ability to predict the risks associated with these ubiquitous contaminants in the environment by understanding their mobility, aggregation behavior and their potential to enhance the transport of other pollutants.

MAEPOPP Center 2015 Best Education Practices Directory

ERIC Educational Resources Information Center

Arendale, David R., Ed.

2015-01-01

Purpose: This directory identifies, describes, and contains evaluative data evidence-based practices that improve academic performance, close the achievement gap, and improve persistence towards graduation for low-income, first-generation, and historically-underrepresented 6th grade through college students. Methodology: The directory was a…

Technical advisory guide (TAG) for bonded wearing course pilot projects.

DOT National Transportation Integrated Search

2003-10-01

A bonded wearing course (BWC) is a gap graded, ultra thin hot-mix asphalt (HMA) mixture applied : over a thick polymer modified asphalt emulsion membrane. The emulsion membrane seals the : existing surface and produces high binder content at the inte...

Construction and performance of ultra thin asphalt friction course

DOT National Transportation Integrated Search

1997-09-01

The Novachip process, also known as ultrathin friction course, was developed in France in 1986. The process utilizes a single piece of equipment to place a thin, gap-graded hot mix asphalt (HMA) onto a relatively thick layer of polymer modified aspha...

The unrealized promise of infant statistical word-referent learning

PubMed Central

Smith, Linda B.; Suanda, Sumarga H.; Yu, Chen

2014-01-01

Recent theory and experiments offer a new solution as to how infant learners may break into word learning, by using cross-situational statistics to find the underlying word-referent mappings. Computational models demonstrate the in-principle plausibility of this statistical learning solution and experimental evidence shows that infants can aggregate and make statistically appropriate decisions from word-referent co-occurrence data. We review these contributions and then identify the gaps in current knowledge that prevent a confident conclusion about whether cross-situational learning is the mechanism through which infants break into word learning. We propose an agenda to address that gap that focuses on detailing the statistics in the learning environment and the cognitive processes that make use of those statistics. PMID:24637154

Fragmentation approach to the point-island model with hindered aggregation: Accessing the barrier energy.

PubMed

González, Diego Luis; Pimpinelli, Alberto; Einstein, T L

2017-07-01

We study the effect of hindered aggregation on the island formation process in a one- (1D) and two-dimensional (2D) point-island model for epitaxial growth with arbitrary critical nucleus size i. In our model, the attachment of monomers to preexisting islands is hindered by an additional attachment barrier, characterized by length l_{a}. For l_{a}=0 the islands behave as perfect sinks while for l_{a}→∞ they behave as reflecting boundaries. For intermediate values of l_{a}, the system exhibits a crossover between two different kinds of processes, diffusion-limited aggregation and attachment-limited aggregation. We calculate the growth exponents of the density of islands and monomers for the low coverage and aggregation regimes. The capture-zone (CZ) distributions are also calculated for different values of i and l_{a}. In order to obtain a good spatial description of the nucleation process, we propose a fragmentation model, which is based on an approximate description of nucleation inside of the gaps for 1D and the CZs for 2D. In both cases, the nucleation is described by using two different physically rooted probabilities, which are related with the microscopic parameters of the model (i and l_{a}). We test our analytical model with extensive numerical simulations and previously established results. The proposed model describes excellently the statistical behavior of the system for arbitrary values of l_{a} and i=1, 2, and 3.

Distance within colloidal dimers probed by rotation-induced oscillations of scattered light.

PubMed

van Vliembergen, Roland W L; van IJzendoorn, Leo J; Prins, Menno W J

2016-01-25

Aggregation processes of colloidal particles are of broad scientific and technological relevance. The earliest stage of aggregation, when dimers appear in an ensemble of single particles, is very important to characterize because it opens routes for further aggregation processes. Furthermore, it represents the most sensitive phase of diagnostic aggregation assays. Here, we characterize dimers by rotating them in a magnetic field and by recording the angle dependence of light scattering. At small scattering angles, the scattering cross section can be approximated by the total cross-sectional area of the dimer. In contrast, at scattering angles around 90 degrees, we reveal that the dependence of the scattering cross section on the dimer angle shows a series of peaks per single 2π rotation of the dimers. These characteristics originate from optical interactions between the two particles, as we have verified with two-particle Mie scattering simulations. We have studied in detail the angular positions of the peaks. It appears from simulations that the influence of particle size polydispersity, Brownian rotation and refractive index on the angular positions of the peaks is relatively small. However, the angular positions of the peaks strongly depend on the distance between the particles. We find a good correspondence between measured data and calculations for a gap of 180 nm between particles having a diameter of 1 micrometer. The experiment and simulations pave the way for extracting distance-specific data from ensembles of dimerizing colloidal particles, with application for sensitive diagnostic aggregation assays.

Effects of blood pressure reduction in mild hypertension: a systematic review and meta-analysis.

PubMed

Sundström, Johan; Arima, Hisatomi; Jackson, Rod; Turnbull, Fiona; Rahimi, Kazem; Chalmers, John; Woodward, Mark; Neal, Bruce

2015-02-03

Effects of blood pressure reduction in persons with grade 1 hypertension are unclear. To investigate whether pharmacologic blood pressure reduction prevents cardiovascular events and deaths in persons with grade 1 hypertension. Trials included in the BPLTTC (Blood Pressure Lowering Treatment Trialists' Collaboration) and trials identified from a previous review and electronic database searches. Patients without cardiovascular disease with blood pressures in the grade 1 hypertension range (140 to 159/90 to 99 mm Hg) who were randomly assigned to an active (antihypertensive drug or more intensive regimen) or control (placebo or less intensive regimen) blood pressure-lowering regimen. Individual-patient data from BPLTTC trials and aggregate data from other trials were extracted. Risk of bias was assessed for all trials. Individual-patient data involved 10 comparisons from trials where most patients had diabetes, and aggregate data involved 3 comparisons from trials of patients without diabetes. The average blood pressure reduction was about 3.6/2.4 mm Hg. Over 5 years, odds ratios were 0.86 (95% CI, 0.74 to 1.01) for total cardiovascular events, 0.72 (CI, 0.55 to 0.94) for strokes, 0.91 (CI, 0.74 to 1.12) for coronary events, 0.80 (CI, 0.57 to 1.12) for heart failure, 0.75 (CI, 0.57 to 0.98) for cardiovascular deaths, and 0.78 (CI, 0.67 to 0.92) for total deaths. Results were similar in secondary analyses. Withdrawal from treatment due to adverse effects was more common in the active groups. Blood pressure reductions and numbers of events were small. Blood pressure-lowering therapy is likely to prevent stroke and death in patients with uncomplicated grade 1 hypertension. Swedish Heart-Lung Foundation, Swedish Research Council, Australian Research Council, and National Health and Medical Research Council of Australia.

A Comprehensive Analysis of the SRS-Schwab Adult Spinal Deformity Classification and Confounding Variables: A Prospective, Non-US Cross-sectional Study in 292 Patients.

PubMed

Hallager, Dennis Winge; Hansen, Lars Valentin; Dragsted, Casper Rokkjær; Peytz, Nina; Gehrchen, Martin; Dahl, Benny

2016-05-01

Cross-sectional analyses on a consecutive, prospective cohort. To evaluate the ability of the Scoliosis Research Society (SRS)-Schwab Adult Spinal Deformity Classification to group patients by widely used health-related quality-of-life (HRQOL) scores and examine possible confounding variables. The SRS-Schwab Adult Spinal Deformity Classification includes sagittal modifiers considered important for HRQOL and the clinical impact of the classification has been validated in patients from the International Spine Study Group database; however, equivocal results were reported for the Pelvic Tilt modifier and potential confounding variables were not evaluated. Between March 2013 and May 2014, all adult spinal deformity patients from our outpatient clinic with sufficient radiographs were prospectively enrolled. Analyses of HRQOL variance and post hoc analyses were performed for each SRS-Schwab modifier. Age, history of spine surgery, and aetiology of spinal deformity were considered potential confounders and their influence on the association between SRS-Schwab modifiers and aggregated Oswestry Disability Index (ODI) scores was evaluated with multivariate proportional odds regressions. P values were adjusted for multiple testing. Two hundred ninety-two of 460 eligible patients were included for analyses. The SRS-Schwab Classification significantly discriminated HRQOL scores between normal and abnormal sagittal modifier classifications. Individual grade comparisons showed equivocal results; however, Pelvic Tilt grade + versus +  + did not discriminate patients according to any HRQOL score. All modifiers showed significant proportional odds for worse aggregated ODI scores with increasing grade levels and the effects were robust to confounding. However, age group and aetiology had individual significant effects. The SRS-Schwab sagittal modifiers reliably grouped patients graded 0 versus + / +  + according to the most widely used HRQOL scores and the effects of increasing grade level on odds for worse ODI scores remained significant after adjusting for potential confounders. However, effects of age group and aetiology should not be neglected. 3.

Survey of home hemodialysis patients and nursing staff regarding vascular access use and care.

PubMed

Spry, Leslie A; Burkart, John M; Holcroft, Christina; Mortier, Leigh; Glickman, Joel D

2015-04-01

Vascular access infections are of concern to hemodialysis patients and nurses. Best demonstrated practices (BDPs) have not been developed for home hemodialysis (HHD) access use, but there have been generally accepted practices (GAPs) endorsed by dialysis professionals. We developed a survey to gather information about training provided and actual practices of HHD patients using the NxStage System One HHD machine. We used GAP to assess training used by nurses to teach HHD access care and then assess actual practice (adherence) by HHD patients. We also assessed training and adherence where GAPs do not exist. We received a 43% response rate from patients and 76% response from nurses representing 19 randomly selected HHD training centers. We found that nurses were not uniformly instructing HHD patients according to GAP, patients were not performing access cannulation according to GAP, nor were they adherent to their training procedures. Identification of signs and symptoms of infection was commonly trained appropriately, but we observed a reluctance to report some signs and symptoms of infection by patients. Of particular concern, when aggregating all steps surveyed, not a single nurse or patient reported training or performing all steps in accordance with GAP. We also identified practices for which there are no GAPs that require further study and may or may not impact outcomes such as infection. Further research is needed to develop strategies to implement and expand GAP, measure outcomes, and ultimately develop BDP for HHD to improve infectious complications. © 2014 The Authors. Hemodialysis International published by Wiley Periodicals, Inc. on behalf of International Society for Hemodialysis.

Thermal tests of large recirculation cooling installations for nuclear power plants

NASA Astrophysics Data System (ADS)

Balunov, B. F.; Lychakov, V. D.; Il'in, V. A.; Shcheglov, A. A.; Maslov, O. P.; Rasskazova, N. A.; Rakhimov, R. Z.; Boyarov, R. A.

2017-11-01

The article presents the results from thermal tests of some recirculation installations for cooling air in nuclear power plant premises, including the volume under the containment. The cooling effect in such installations is produced by pumping water through their heat-transfer tubes. Air from the cooled room is blown by a fan through a bundle of transversely finned tubes and is removed to the same room after having been cooled. The finning of tubes used in the tested installations was made of Grade 08Kh18N10T and Grade 08Kh18N10 stainless steels or Grade AD1 aluminum. Steel fins were attached to the tube over their entire length by means of high-frequency welding. Aluminum fins were extruded on a lathe from the external tube sheath into which a steel tube had preliminarily been placed. Although the fin extrusion operation was accompanied by pressing the sheath inner part to the steel tube, tight contact between them over the entire surface was not fully achieved. In view of this, the air gap's thermal resistance coefficient was introduced in calculating the heat transfer between the heat-transferring media. The air gap average thickness was determined from the test results taking into account the gap variation with temperature due to different linear expansion coefficients of steel and aluminum. These tests, which are part of the acceptance tests of the considered installations, were carried out at the NPO TsKTI test facility and were mainly aimed at checking if the obtained thermal characteristics were consistent with the values calculated according to the standard recommendations with introduction, if necessary, of modifications to those recommendations.

Recapitulation of Tumor Heterogeneity and Molecular Signatures in a 3D Brain Cancer Model with Decreased Sensitivity to Histone Deacetylase Inhibition

PubMed Central

Smith, Stuart J.; Wilson, Martin; Ward, Jennifer H.; Rahman, Cheryl V.; Peet, Andrew C.; Macarthur, Donald C.; Rose, Felicity R. A. J.; Grundy, Richard G.; Rahman, Ruman

2012-01-01

Introduction Physiologically relevant pre-clinical ex vivo models recapitulating CNS tumor micro-environmental complexity will aid development of biologically-targeted agents. We present comprehensive characterization of tumor aggregates generated using the 3D Rotary Cell Culture System (RCCS). Methods CNS cancer cell lines were grown in conventional 2D cultures and the RCCS and comparison with a cohort of 53 pediatric high grade gliomas conducted by genome wide gene expression and microRNA arrays, coupled with immunohistochemistry, ex vivo magnetic resonance spectroscopy and drug sensitivity evaluation using the histone deacetylase inhibitor, Vorinostat. Results Macroscopic RCCS aggregates recapitulated the heterogeneous morphology of brain tumors with a distinct proliferating rim, necrotic core and oxygen tension gradient. Gene expression and microRNA analyses revealed significant differences with 3D expression intermediate to 2D cultures and primary brain tumors. Metabolic profiling revealed differential profiles, with an increase in tumor specific metabolites in 3D. To evaluate the potential of the RCCS as a drug testing tool, we determined the efficacy of Vorinostat against aggregates of U87 and KNS42 glioblastoma cells. Both lines demonstrated markedly reduced sensitivity when assaying in 3D culture conditions compared to classical 2D drug screen approaches. Conclusions Our comprehensive characterization demonstrates that 3D RCCS culture of high grade brain tumor cells has profound effects on the genetic, epigenetic and metabolic profiles of cultured cells, with these cells residing as an intermediate phenotype between that of 2D cultures and primary tumors. There is a discrepancy between 2D culture and tumor molecular profiles, and RCCS partially re-capitulates tissue specific features, allowing drug testing in a more relevant ex vivo system. PMID:23272238

Do scheduled caste and scheduled tribe women legislators mean lower gender-caste gaps in primary schooling in India?

PubMed

Halim, Nafisa; Yount, Kathryn M; Cunningham, Solveig

2016-07-01

Despite India's substantial investments in primary schooling, gaps in schooling persist across gender and caste-with scheduled caste and scheduled tribe (SC/ST) girls being particularly disadvantaged. The representation of SC/ST women in state legislatures may help to mitigate this disadvantage. Specifically, because of her intersecting gender and caste/tribe identities, a SC/ST woman legislator might maintain a strong sense of solidarity especially with SC/ST girls and women, and support legislative policies benefitting SC/ST girls. Consequently, for this reason, we expect that living in a district where SC/ST women represent in state legislatures in a higher proportion may increase SC/ST girls' primary school completion, progression and performance. We tested this hypothesis using district-level data between 2000 and 2004 from the Indian Election Commission, the 2004/5 India Human Development Survey, and the Indian Census of 2001. As expected, the representation of SC/ST women in state legislatures was positively associated with SC/ST girls' grade completion and age-appropriate grade progression but was apparent not SC/ST girls' primary-school performance. SC/ST women's representation in state legislatures may reduce gender-caste gaps in primary-school attainment in India. Copyright © 2016. Published by Elsevier Inc.

Albumen Glue, New Material for Conjunctival Graft Surgery, an Animal Experiment

NASA Astrophysics Data System (ADS)

Kartiwa, A.; Miraprahesti, R.; Sovani, I.; Enus, S.; Boediono, A.

2017-02-01

Attach conjunctival graft commonly used are suture technique and fibrin glue. This study was to investigate albumen glue as an alternative to suture technique in attaching conjunctival graft in rabbits. Aim of this study was to compare the conjunctival wound healing between albumen glue and suture technique in rabbit eye as a model. There was an experimental animal study included 32 eyes (16 rabbits) in PT. Bio Farma (Persero) and Histology Laboratory, Faculty of Medicine, Padjadjaran University from March 2014 to July 2104. The study consisted of albumen glue group and suture technique group. The examination included the comparison of conjunctival graft attachment and histologic examination by microscopically was done to obtain the wound gap, then analyze by Mann-Whitney test. The results indicated that the graft attachment was significantly better-using albumen glue (grade 4) compared to suture (grade 2-3) on day-1 after surgery (p=0,000). The wound gap was smaller using albumen glue (0-0,33 μm versus 5,33-14 μm ; p=0,0005) on 10 minutes after surgery and 0 μm versus 0,33-4 μm ; p=0,0005 on day-7 after surgery. In conclusion, the graft attachment using albumen glue was better and the wound gap was smaller using albumen glue than suture technique.

Do scheduled caste and scheduled tribe women legislators mean lower gender-caste gaps in primary schooling in India?

PubMed Central

Halim, Nafisa; Yount, Kathryn M.; Cunningham, Solveig

2017-01-01

Despite India’s substantial investments in primary schooling, gaps in schooling persist across gender and caste—with scheduled caste and scheduled tribe (SC/ST) girls being particularly disadvantaged. The representation of SC/ST women in state legislatures may help to mitigate this disadvantage. Specifically, because of her intersecting gender and caste/tribe identities, a SC/ST woman legislator might maintain a strong sense of solidarity especially with SC/ST girls and women, and support legislative policies benefitting SC/ST girls. Consequently, for this reason, we expect that living in a district where SC/ST women represent in state legislatures in a higher proportion may increase SC/ST girls’ primary school completion, progression and performance. We tested this hypothesis using district-level data between 2000 and 2004 from the Indian Election Commission, the 2004/5 India Human Development Survey, and the Indian Census of 2001. As expected, the representation of SC/ST women in state legislatures was positively associated with SC/ST girls’ grade completion and age-appropriate grade progression but was apparent not SC/ST girls’ primary-school performance. SC/ST women’s representation in state legislatures may reduce gender-caste gaps in primary-school attainment in India. PMID:27194655

The Math Gap: a description of the mathematics performance of preschool-aged deaf/hard-of-hearing children.

PubMed

Pagliaro, Claudia M; Kritzer, Karen L

2013-04-01

Over decades and across grade levels, deaf/hard-of-hearing (d/hh) student performance in mathematics has shown a gap in achievement. It is unclear, however, exactly when this gap begins to emerge and in what areas. This study describes preschool d/hh children's knowledge of early mathematics concepts. Both standardized and nonstandardized measures were used to assess understanding in number, geometry, measurement, problem solving, and patterns, reasoning and algebra. Results present strong evidence that d/hh students' difficulty in mathematics may begin prior to the start of formal schooling. Findings also show areas of strength (geometry) and weakness (problem solving and measurement) for these children. Evidence of poor foundational performance may relate to later academic achievement.

Inhibition of rabbit platelet activation in vitro by antagonists of platelet-activating factor (PAF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, C.P.; Wood, K.L.

1986-03-05

The authors used washed, (/sup 3/H)serotonin-labeled rabbit platelets to study the in vitro aggregation and secretion responses induced by graded doses of PAF in the presence or absence of specific antagonists of PAF. These antagonists included CV-3988, L-652,731, triazolam and alprazolam. Platelets were pretreated with either an antagonist or the appropriate diluent for 60 sec prior to the addition of PAF (2 x 10/sup -10/ to 2 x 10/sup -7/ M). Aggregation was monitored continuously and recorded as the height of the aggregation tracing at 60 sec post-PAF. Secretion of (/sup 3/H)-serotonin was measured in a sample of the plateletsmore » removed at 60 sec post-PAF. When 2 x 10/sup -10/ M PAF was used as the stimulus, the concentration of antagonist needed for 50% inhibition (IC/sub 50/) of secretion was obtained at 0.05 ..mu..M, 0.15 ..mu..M, 0.6 ..mu..M and 2.5 ..mu..M, respectively, for L-652,731, CV-3988, triazolam and alprazolam. The corresponding IC/sub 50/ for aggregation was obtained at 0.2 ..mu..M, 0.1 ..mu..M, 1.5 ..mu..M and 6.5 ..mu..M, respectively. The inhibitory effects of these antagonists could be overcome by increasing the dose of PAF used. Although all of the antagonists were capable of completely inhibiting platelet aggregation and secretion, L-652,731 was the most potent PAF antagonist on a molar basis.« less

A Study on Suitability of EAF Oxidizing Slag in Concrete: An Eco-Friendly and Sustainable Replacement for Natural Coarse Aggregate

PubMed Central

Sekaran, Alan; Palaniswamy, Murthi; Balaraju, Sivagnanaprakash

2015-01-01

Environmental and economic factors increasingly encourage higher utility of industrial by-products. The basic objective of this study was to identify alternative source for good quality aggregates which is depleting very fast due to fast pace of construction activities in India. EAF oxidizing slag as a by-product obtained during the process in steel making industry provides great opportunity to utilize it as an alternative to normally available coarse aggregates. The primary aim of this research was to evaluate the physical, mechanical, and durability properties of concrete made with EAF oxidizing slag in addition to supplementary cementing material fly ash. This study presents the experimental investigations carried out on concrete grades of M20 and M30 with three mixes: (i) Mix A, conventional concrete mix with no material substitution, (ii) Mix B, 30% replacement of cement with fly ash, and (iii) Mix C, 30% replacement of cement with fly ash and 50% replacement of coarse aggregate with EAF oxidizing slag. Tests were conducted to determine mechanical and durability properties up to the age of 90 days. The test results concluded that concrete made with EAF oxidizing slag and fly ash (Mix C) had greater strength and durability characteristics when compared to Mix A and Mix B. Based on the overall observations, it could be recommended that EAF oxidizing slag and fly ash could be effectively utilized as coarse aggregate replacement and cement replacement in all concrete applications. PMID:26421315

A Study on Suitability of EAF Oxidizing Slag in Concrete: An Eco-Friendly and Sustainable Replacement for Natural Coarse Aggregate.

PubMed

Sekaran, Alan; Palaniswamy, Murthi; Balaraju, Sivagnanaprakash

2015-01-01

Environmental and economic factors increasingly encourage higher utility of industrial by-products. The basic objective of this study was to identify alternative source for good quality aggregates which is depleting very fast due to fast pace of construction activities in India. EAF oxidizing slag as a by-product obtained during the process in steel making industry provides great opportunity to utilize it as an alternative to normally available coarse aggregates. The primary aim of this research was to evaluate the physical, mechanical, and durability properties of concrete made with EAF oxidizing slag in addition to supplementary cementing material fly ash. This study presents the experimental investigations carried out on concrete grades of M20 and M30 with three mixes: (i) Mix A, conventional concrete mix with no material substitution, (ii) Mix B, 30% replacement of cement with fly ash, and (iii) Mix C, 30% replacement of cement with fly ash and 50% replacement of coarse aggregate with EAF oxidizing slag. Tests were conducted to determine mechanical and durability properties up to the age of 90 days. The test results concluded that concrete made with EAF oxidizing slag and fly ash (Mix C) had greater strength and durability characteristics when compared to Mix A and Mix B. Based on the overall observations, it could be recommended that EAF oxidizing slag and fly ash could be effectively utilized as coarse aggregate replacement and cement replacement in all concrete applications.

Fifth through Eighth Grade Students' Difficulties in Constructing Bar Graphs: Data Organization, Data Aggregation, and Integration of a Second Variable

ERIC Educational Resources Information Center

Garcia-Mila, Merce; Marti, Eduard; Gilabert, Sandra; Castells, Marina

2014-01-01

Studies that consider the displays that students create to organize data are not common in the literature. This article compares fifth through eighth graders' difficulties with the creation of bar graphs using either raw data (Study 1, n = 155) or a provided table (Study 2, n = 152). Data in Study 1 showed statistical differences for the type of…

Performance evaluation of high modulus asphalt concrete mixes

NASA Astrophysics Data System (ADS)

Haritonovs, V.; Tihonovs, J.; Zaumanis, M.

2016-04-01

Dolomite is one of the most available sedimentary rocks in the territory of Latvia. Dolomite quarries contain about 1000 million tons of this material. However, according to Latvian Road Specifications, this dolomite cannot be used for average and high intensity roads because of its low quality (mainly, LA index). Therefore, mostly imported magmatic rocks (granite, diabase, gabbro, basalt) or imported dolomite are used which makes asphalt expensive. However, practical experience shows that even with these high quality materials roads exhibit rutting, fatigue and thermal cracks. The aim of the research is to develop a high performance asphalt concrete for base and binder courses using only locally available aggregates. In order to achieve resistance against deformations at a high ambient temperature, a hard grade binder was used. Workability, fatigue and thermal cracking resistance, as well as sufficient water resistance is achieved by low porosity (3-5%) and higher binder content compared to traditional asphalt mixtures. The design of the asphalt includes a combination of empirical and performance based tests, which in laboratory circumstances allow simulating traffic and environmental loads. High performance AC 16 base asphalt concrete was created using local dolomite aggregate with polymer modified (PMB 10/40-65) and hard grade (B20/30) bitumen. The mixtures were specified based on fundamental properties in accordance to EN 13108-1 standard.

Adding to the Education Debt: Depressive Symptoms Mediate the Association between Racial Discrimination and Academic Performance in African Americans.

PubMed

English, Devin; Lambert, Sharon F; Ialongo, Nicholas S

2016-08-01

Although the United States faces a seemingly intractable divide between white and African American academic performance, there remains a dearth of longitudinal research investigating factors that work to maintain this gap. The present study examined whether racial discrimination predicted the academic performance of African American students through its effect on depressive symptoms. Participants were a community sample of African American adolescents (N=495) attending urban public schools from grade 7 to grade 9 (Mage=12.5). Structural equation modeling revealed that experienced racial discrimination predicted increases in depressive symptoms 1year later, which, in turn, predicted decreases in academic performance the following year. These results suggest that racial discrimination continues to play a critical role in the academic performance of African American students and, as such, contributes to the maintenance of the race-based academic achievement gap in the United States. Copyright © 2016 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

Will Not Want: Self-Control Rather than Motivation Explains the Female Advantage in Report Card Grades

PubMed Central

Duckworth, Angela L.; Shulman, Elizabeth P.; Mastronarde, Andrew J.; Patrick, Sarah D.; Zhang, Jinghui; Druckman, Jeremy

2015-01-01

Girls earn better grades than boys, but the mechanism explaining this gender difference is not well understood. We examined the relative importance of self-control and motivation in explaining the female advantage in grades. In Study 1, we surveyed middle school teachers and found they judged girls to be higher in both school motivation and self-control. In Studies 2 and 3—using self-reported motivation and teacher- and/or parent-reported self-control, and quarterly and final grades obtained from school records—we find that self-control, but not school motivation, helps to explain the gender gap in academic performance. In these studies, girls appeared to be more self-controlled than boys, but—contrary to teacher judgments in Study 1—did not appear to be more motivated to do well in school. PMID:25883522

Early Adolescent Temperament, Parental Monitoring, and Substance Use in Mexican-Origin Adolescents

PubMed Central

Clark, D. Angus; Donnellan, M. Brent; Robins, Richard W.; Conger, Rand D.

2015-01-01

Previous studies suggest that temperamental dispositions are associated with substance use. However, most research supporting this association has relied on European American samples (Stautz & Cooper, 2013). We addressed this gap by evaluating the prospective relations between 5th grade temperament and 9th grade substance use in a longitudinal sample of Mexican-origin youth (N = 674). Effortful control and trait aggressiveness predicted 9th grade substance use, intentions, and expectations, even after controlling for 5th grade substance use. Additionally, we found an interaction between temperament and parental monitoring such that monitoring is a protective factor for early substance use primarily for youth with temperamental tendencies associated with risk for substance use (e.g., low effortful control and aggression). Results add to the growing literature demonstrating that early manifestations of self-control are related to consequential life outcomes. PMID:25841175

Morphological Characteristics of Particulate Material Formed from High Velocity Impact of Depleted Uranium Projectiles with Armor Targets

DTIC Science & Technology

1978-11-01

Magnification Showing Aggregation of Ultrafine Particles ; Gap Between Bars Represents 0.5 pm. .......... ... 15 iv LIST OF FIGURES (CONCLUDED) Figure Title...subsequent forma- tion of smaller particulates. An unexpected phenomenon was the formation of ultrafine particles less than 0.1 pm in diameter. These...and the highly reactive nature of pyrophoric depleted uranium. Ti ese ultrafine particles exhibited an extreme tendency to coalesce, probably due to

Value-added utilisation of recycled concrete in hot-mix asphalt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, Yiik Diew; Sun, Darren Delai; Lai, Dickson

2007-07-01

The feasibility of partial substitution of granite aggregate in hot-mix asphalt (HMA) with waste concrete aggregate was investigated. Three hybrid HMA mixes incorporating substitutions of granite fillers/fines with 6%, 45% untreated, and 45% heat-treated concrete were evaluated by the Marshall mix design method; the optimum binder contents were found to be 5.3%, 6.5% and 7.0% of grade Pen 60/70 bitumen, respectively. All three hybrid mixes satisfied the Marshall criteria of the Singapore Land Transport Authority (LTA) W3B wearing course specification. The hybrid mix with 6% concrete fillers gave comparable resilient modulus and creep resistance as the conventional W3B mix, whilemore » hybrid mixes with higher concrete substitutions achieved better performance. X-ray diffraction (XRD) showed the distinct presence of free lime in the heat-treated concrete, while the scanning electron microscope (SEM) provided an in-depth perspective of the concrete grains in the HMA matrix. The results suggest feasible use of waste concrete as partial aggregate substitution in HMA.« less

Sustainable materials used as stone column filler: A short review

NASA Astrophysics Data System (ADS)

Zukri, Azhani; Nazir, Ramli

2018-04-01

Stone columns (also known as granular piles) are one of the methods for soft soil stabilization and typically used to increase bearing capacity and stability of slope.; Apart from decreasing the compressibility of loose and fine graded soils, it also accelerates the consolidation effect by improving the drainage path for pore water pressure dissipation and reduces the liquefaction potential of soils during earthquake event. Stone columns are probably the most “natural” ground treatment method or foundation system in existence to date. The benefit of stone columns is owing to the partial replacement of compressible soil by more competent materials such as stone aggregate, sand and other granular materials. These substitutes also act as reinforcement material, hence increasing overall strength and stiffness of the soft soil. Nowadays, a number of research has been conducted on the behaviour and performance of stone columns with various materials utilized as column filler replacing the normal aggregate. This paper will review extensively on previously conducted research on some of the materials used as stone column backfill materials, its suitability and the effectiveness as a substitute for regular aggregates in soft soil improvement works.

The gender gap in student engagement: The role of teachers' autonomy support, structure, and involvement.

PubMed

Lietaert, Sofie; Roorda, Debora; Laevers, Ferre; Verschueren, Karine; De Fraine, Bieke

2015-12-01

The gender gap in education in favour of girls is a widely known phenomenon. Boys generally have higher dropout rates, obtain lower grades, and show lower engagement. Insight into factors related to these academic outcomes could help to address the gender gap. This study investigated, for Dutch language classes, (1) how boys and girls differ in behavioural engagement, (2) which teacher support dimensions (autonomy support, structure, involvement) may explain gender differences in engagement (mediation hypothesis), and (3) whether and which of these teacher support dimensions matter more for boys' as opposed to girls' engagement (moderation or differential effects hypothesis). A total of 385 Grade 7 students and their 15 language teachers participated in this study. Teacher support was assessed through student reports. Student engagement was measured using student, teacher, and observer reports. By means of structural equation modelling, the mediating role of the teacher support dimensions for gender differences in behavioural engagement was tested. The potential differential role of the teacher support dimensions for boys' and girls' engagement was investigated through multigroup analysis. Boys were less engaged than girls and reported lower support from their teacher. Autonomy support and involvement partially mediated the relationship between gender and behavioural engagement. Autonomy support was demonstrated to be a protective factor for boys' engagement but not for girls'. Structure and involvement contributed equally to engagement for both sexes. Although involvement and autonomy support partly explained the gender gap in engagement (mediation hypothesis), more support was found for differential effects of autonomy support on boys' versus girls' engagement (differential effects hypothesis). © 2015 The British Psychological Society.

Nathan Glazer Explains the Black Faculty Gap.

ERIC Educational Resources Information Center

Glazer, Nathan

2003-01-01

Contends that the low number of academically high-scoring black students at selective colleges, combined with the attraction of alternate career opportunities, largely explains the shortage of black doctoral candidates. The lower grades black students receive at selective institutions may discourage them from choosing academic careers. Suggests…

Manufacturing Curriculum Grant. Final Report.

ERIC Educational Resources Information Center

Scarborough, Jule Dee

A manufacturing curriculum for secondary vocational programs was designed to bridge the gap between grades 9-10 level courses and the community college-level curriculum of the Illinois Plan for Industrial Education. During the project, a literature review of manufacturing curriculum materials was conducted, a manufacturing conceptual framework was…

Third Working Meeting on Gallium Arsenide Solar Cells

NASA Technical Reports Server (NTRS)

Walker, G. H. (Compiler)

1976-01-01

Research results are reported for GaAs Schottky barrier solar cells, GaAlAs/GaAs heteroface solar cells, and GaAlAs graded band gap solar cells. Related materials studies are presented. A systems study for GaAs and Si solar concentrator systems is given.

Conferencing the SMART Way

ERIC Educational Resources Information Center

Akers, Pamela

2005-01-01

As schools across the nation strive to eliminate student achievement gaps, it has become more crucial than ever for parents to be involved, especially parents of children achieving below grade level. In Maryland's Howard County Public Schools, a parent-teacher conferencing program called SMART, focused on Specific, Measurable, Achievable,…

Comprehensive School Reform: Meta-Analytic Evidence of Black-White Achievement Gap Narrowing1

PubMed Central

Gorey, Kevin M.

2016-01-01

This meta-analysis extends a previous review of the achievement effects of comprehensive school reform (CSR) programs (Borman, Hewes, Overman, & Brown, 2003). That meta-analysis observed significant effects of well endowed and well-researched programs, but it did not account for race/ethnicity. This article synthesizes 34 cohort or quasi-experimental outcomes of studies that incorporated the policy-critical characteristic of race/ethnicity. Findings: compared with matched traditional schools, the black-white achievement gap narrowed significantly more among students in CSR schools. In addition, the aggregate effects were large, substantially to completely eliminating the achievement gap between African American and non-Hispanic white students in elementary and middle schools. Title I policies before or after the No Child Left Behind Act of 2001 seem to have had essentially no impact on the black-white achievement gap. Curricular and testing mandates along with the threat of sanctions without concomitant resource supports seem to have failed. This study suggests that educational achievement inequities need not be America’s destiny. It seems that they could be eliminated through concerted political will and ample resource commitments to evidence-based educational programs. PMID:27453681

Teachers' Promotion or Inhibition of Children's Aggression Depends on Peer-Group Characteristics.

PubMed

Peets, Kätlin; Kikas, Eve

2017-01-01

Researchers have increasingly started to pay attention to how contextual factors, such as the classroom peer context and the quality of student-teacher interactions, influence children's aggressive behavior. This longitudinal study was designed to examine the degree to which benefits and costs of different teaching practices (child-centered and child-dominated) would be dependent on the initial peer-group composition (aggregate levels of aggression and victimization at the beginning of first grade). Teachers provided ratings of aggression and victimization (N = 523 first-grade students; M age at the beginning of first grade = 7.49 years, SD = 0.52). Information about different teaching practices was obtained via observations. Our results show that whereas child-centered practices are beneficial in high-victimization classrooms, child-dominated practices inhibit the development of aggression in low-victimization classroom contexts. Our findings highlight the importance of moving beyond main-effect models to studying how different contextual influences interact to promote, or inhibit, the development of aggression.

Flooding Vocabulary Gaps to Accelerate Word Learning

ERIC Educational Resources Information Center

Brabham, Edna; Buskist, Connie; Henderson, Shannon Coman; Paleologos, Timon; Baugh, Nikki

2012-01-01

Students entering school with limited vocabularies are at a disadvantage compared to classmates with robust knowledge of words and meanings. Teaching a few unrelated words at a time is insufficient for catching these students up with peers and preparing them to comprehend texts they will encounter across the grades. This article presents…

Teaching Smarter: An Unconventional Guide to Boosting Student Success

ERIC Educational Resources Information Center

Kelley, Patrick

2015-01-01

This refreshingly frank handbook shows teachers how to close the achievement gap in their classrooms by teaching students innovative paths to academic success. Drawing on over 20 years' experience, Kelley presents straightforward strategies for helping learners improve their grades and test scores and experience greater school engagement--all…

Understanding the Discipline Gap from an Ecological Perspective

ERIC Educational Resources Information Center

McElderry, Cathy G.; Cheng, Tyrone C.

2014-01-01

This study investigated school exclusion's relationships with student characteristics, mother characteristics, parental involvement, school location, and service provision. The researchers examined data from 4,837 students in seventh to 12th grade extracted from a national data set. Multivariate results showed that student's age, gender,…

Number Sense Made Simple Using Number Patterns

ERIC Educational Resources Information Center

Su, Hui Fang Huang; Marinas, Carol; Furner, Joseph

2011-01-01

This article highlights investigating intriguing number patterns utilising an emerging technology called the Square Tool. Mathematics teachers of grades K-12 will find the Square Tool useful in making connections and bridging the gap from the concrete to the abstract. Pattern recognition helps students discover various mathematical concepts. With…

Learning Connections. Learning Times. Volume 6, Number 3

ERIC Educational Resources Information Center

LDA Minnesota, 2008

2008-01-01

This issue of "Learning Times" discusses closing the achievement gap for low-income kids. Too many low-income children in Minnesota lag behind grade level in reading and math. LDA's (Learning Disabilities Association's) Learning Connections program serves these students who have fallen behind, but who do not receive special education…

2016 EOA National Best Practices Center Directory (2nd Ed.)

ERIC Educational Resources Information Center

Arendale, David R., Ed.

2016-01-01

This 2016 directory identifies, describes, and contains evaluative data evidence-based practices that improve academic performance, close the achievement gap, and improve persistence towards graduation for low-income, first-generation, and historically-underrepresented 6th grade through college students. The directory was a production of the…

Emotional Intelligence and Academic Achievement in 11th Grade At-Risk Students

ERIC Educational Resources Information Center

Nelson, Patricia Diane

2009-01-01

As the emphasis on measures of student academic achievement increases, educational researchers and practitioners are interested in identifying factors that demonstrate effectiveness in supporting student achievement. This quantitative, correlational study explored the influence of emotional intelligence on closing the achievement gap. A study of…

Instructional Materials in Consumer Education: Interpersonal Relations.

ERIC Educational Resources Information Center

North Dakota State Board for Vocational Education, Bismarck.

The seven interpersonal relations units in the consumer education guide are: Expressing Satisfaction or Dissatisfaction with Consumer Goods and Services, What to Do in Case of a Financial Crisis, Bridging the Generation Gap, Rebellion, Emotions, Discovering Myself, and Dual Role (homemaker/wage earner). Grade levels of the units, are…

Construction and performance of a stone matrix asphalt mix test section in Virginia.

DOT National Transportation Integrated Search

1995-01-01

SMA is a gap-graded mix filled with a rich asphalt-fines mastic developed in Europe. In 1991 five states constructed trial sections to determine if satisfactory mixes could be produced in the United States with current materials and high rates of pro...

Collaborative Action Research for Middle Grades Improvement

ERIC Educational Resources Information Center

Downes, John M.; Bishop, Penny A.; Swallow, Meredith; Olofson, Mark; Hennessey, Susan

2016-01-01

Technology's rapid evolution applies constant pressure to educational organizations, suggesting a need to continually re-envision schools for the digital age. Yet educators often struggle to understand the growing chasm between students' out-of-school and in-school technology lives. This gap is particularly noticeable during the middle grades…

Teaching Vocabulary to English Language Learners

ERIC Educational Resources Information Center

Daniels, Sharilyn Fox

2009-01-01

This study determined if the vocabulary gap for English Language Learners (ELLs) and their peers could be bridged through providing home interventions with multiple exposures to words, definitions, model sentences and context. Ninety-one first grade students from a public school in Southern California with a 95% ELL population were researched. ELL…

High School FCS Program Reaches Out to Senior Citizens

ERIC Educational Resources Information Center

Sowers, Margaret A.

2007-01-01

"Bridging the Gap: Intergenerational Appreciation" is an educational partnership between community residents and high school family and consumer sciences (FCS) students in the Cornwall-Lebanon School District in Lebanon, Pennsylvania. The program provides 10th, 11th, and 12th grade students opportunities to be actively involved with the…

Early Learning: Birth to Third Grade Continuum. Annotated Bibliography

ERIC Educational Resources Information Center

Hite, Jenny

2014-01-01

Recent studies indicate that persistent achievement gaps among children begin as early as 18 months, years before most publicly funded prekindergarten programs offer enrollment. Early childhood development necessitates more than access to pre-K at age four. Proper brain development requires adequate nutrition, access to quality healthcare, and…

Math Attitudes of Computer Education and Instructional Technology Students

ERIC Educational Resources Information Center

Tekerek, Mehmet; Yeniterzi, Betul; Ercan, Orhan

2011-01-01

Computer Education and Instructional Technology (CEIT) Departments train computer teachers to fill gap of computer instructor in all grades of schools in Turkey. Additionally graduates can also work as instructional technologist or software developer. The curriculum of CEIT departments includes mathematics courses. The aim of this study is to…

Assessment Policy and Practices: Test Accommodations for Students without Disabilities?

ERIC Educational Resources Information Center

Lin, Pei-Ying

2013-01-01

This study investigated accommodations for students without disabilities in order to fill critical gaps in both knowledge and practices in fields of special education and educational assessments. In Ontario, students at different grade levels were assessed by the provincial assessments developed by the Education Quality and Accountability Office…

The Uneven Implementation of Universal School Policies: Maternal Education and Florida's Mandatory Grade Retention Policy

ERIC Educational Resources Information Center

LiCalsi, Christina; Ozek, Umut; Figlio, David

2016-01-01

Research consistently demonstrates a strong, positive relationship between parents' socioeconomic status and children's educational achievement. This achievement gap is already present when children enter school in kindergarten and, despite the numerous policies aimed at leveling the educational playing field for disadvantaged students, it does…

Reducing the racial achievement gap: a social-psychological intervention.

PubMed

Cohen, Geoffrey L; Garcia, Julio; Apfel, Nancy; Master, Allison

2006-09-01

Two randomized field experiments tested a social-psychological intervention designed to improve minority student performance and increase our understanding of how psychological threat mediates performance in chronically evaluative real-world environments. We expected that the risk of confirming a negative stereotype aimed at one's group could undermine academic performance in minority students by elevating their level of psychological threat. We tested whether such psychological threat could be lessened by having students reaffirm their sense of personal adequacy or "self-integrity." The intervention, a brief in-class writing assignment, significantly improved the grades of African American students and reduced the racial achievement gap by 40%. These results suggest that the racial achievement gap, a major social concern in the United States, could be ameliorated by the use of timely and targeted social-psychological interventions.

Properties and shock response of PMMA

NASA Astrophysics Data System (ADS)

Jordan, Jennifer L.; Casem, Daniel; Moy, Paul; Walter, Timothy

2017-01-01

Polymethylmethacrylate (PMMA) is used widely in shock experiments as a window material and in explosive characterization tests, e.g. gap tests, as a shock mitigation material. In order to simulate the complex loading present in a gap test, the constitutive response of the PMMA must be well understood. However, it is not clear what characterization must be done when the PMMA material is changed, e.g. changing supplier, and the Rohm and Haas Type II UVA PMMA, which was used for many of the calibration experiments, is no longer available. In this paper, we will present characterization results on legacy Rohm and Haas Type II UVA in comparison with a new PMMA grade proposed for use in gap tests. Planar shock experiments are performed to determine the compression and release response.

Light scattering management of dye-sensitized solar cells based on double-layered photoanodes aided by uniform TiO{sub 2} aggregates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakhshayesh, A.M., E-mail: bakhshayesh@alum.sharif.edu

2016-01-15

Highlights: • A new architecture of double-layered TiO{sub 2} electrodes is presented. • The electrode contains two alternate layers of TiO{sub 2} nanoparticles and aggregates. • The aggregates layers are deposited onto the nanocrystalline layer. • The new design showed improved efficiency compared to conventional cells. - Abstract: This study presents a new double-layered TiO{sub 2} film containing a nanocrystalline under-layer and a uniform, sponge-like light scattering over-layer for dye-sensitized solar cells (DSCs) application. The over-layer is composed of 2-μm-diameter uniform aggregates, containing small nanoparticles with the average grain size of 20 nm. X-ray diffraction reveals that the light scatteringmore » layer has a mixture of anatase and rutile phases, whereas the nanocrystalline layer has a pure anatase phase. Ultraviolet–visible (UV–vis) spectra show that the light scattering layer has lower band gap energy than the nanocrystalline under-layer, extending the absorption of TiO{sub 2} into visible region. Diffuse reflectance spectroscopy demonstrates that the double-layered electrode enjoyed better light scattering ability. The double-layered DSC shows the highest power conversion efficiency of 7.69% and incident photon-to-current efficiency of 88% as a result of higher light harvesting and less recombination which is demonstrated by electrochemical impedance spectroscopy.« less

Investigation and Rehabilitation to Extend Service Life of DSS-13 Antenna Concrete Foundation

NASA Technical Reports Server (NTRS)

Riewe, A. A., Jr.

1984-01-01

An investigation to establish the cause and, devise a repair technique to maintain the serviceability of the DSS-13 26 meter antenna is described. Core samples are obtained from the concrete and various laboratory tests conducted. In-place nondestructive type tests are also performed. The tests established that the concrete is deteriorating because of alkali aggregate reactivity. This is a phenomenon wherein certain siliceous constituents present in some aggregates react with alkalies in the portland cement to produce a silica gel which, in turn, imbibes water, swells, and cracks the concrete. The scheme consists of a supplemental steel frame friction pile anchored grade beam encircling the existing foundation. This system provides adequate bracing against base shear and overturning due to seismic loading. Larger cracks are sealed using a pressure injected two-component epoxy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Kyoungsoo, E-mail: kpark16@illinois.ed; Paulino, Glaucio H.; Roesler, Jeffery

A simple, effective, and practical constitutive model for cohesive fracture of fiber reinforced concrete is proposed by differentiating the aggregate bridging zone and the fiber bridging zone. The aggregate bridging zone is related to the total fracture energy of plain concrete, while the fiber bridging zone is associated with the difference between the total fracture energy of fiber reinforced concrete and the total fracture energy of plain concrete. The cohesive fracture model is defined by experimental fracture parameters, which are obtained through three-point bending and split tensile tests. As expected, the model describes fracture behavior of plain concrete beams. Inmore » addition, it predicts the fracture behavior of either fiber reinforced concrete beams or a combination of plain and fiber reinforced concrete functionally layered in a single beam specimen. The validated model is also applied to investigate continuously, functionally graded fiber reinforced concrete composites.« less

National differences in gender–science stereotypes predict national sex differences in science and math achievement

PubMed Central

Nosek, Brian A.; Smyth, Frederick L.; Sriram, N.; Lindner, Nicole M.; Devos, Thierry; Ayala, Alfonso; Bar-Anan, Yoav; Bergh, Robin; Cai, Huajian; Gonsalkorale, Karen; Kesebir, Selin; Maliszewski, Norbert; Neto, Félix; Olli, Eero; Park, Jaihyun; Schnabel, Konrad; Shiomura, Kimihiro; Tulbure, Bogdan Tudor; Wiers, Reinout W.; Somogyi, Mónika; Akrami, Nazar; Ekehammar, Bo; Vianello, Michelangelo; Banaji, Mahzarin R.; Greenwald, Anthony G.

2009-01-01

About 70% of more than half a million Implicit Association Tests completed by citizens of 34 countries revealed expected implicit stereotypes associating science with males more than with females. We discovered that nation-level implicit stereotypes predicted nation-level sex differences in 8th-grade science and mathematics achievement. Self-reported stereotypes did not provide additional predictive validity of the achievement gap. We suggest that implicit stereotypes and sex differences in science participation and performance are mutually reinforcing, contributing to the persistent gender gap in science engagement. PMID:19549876

Values Affirmation Intervention Reduces Achievement Gap between Underrepresented Minority and White Students in Introductory Biology Classes

PubMed Central

Jordt, Hannah; Eddy, Sarah L.; Brazil, Riley; Lau, Ignatius; Mann, Chelsea; Brownell, Sara E.; King, Katherine; Freeman, Scott

2017-01-01

Achievement gaps between underrepresented minority (URM) students and their white peers in college science, technology, engineering, and mathematics classrooms are persistent across many white-majority institutions of higher education. Attempts to reduce this phenomenon of underperformance through increasing classroom structure via active learning have been partially successful. In this study, we address the hypothesis that the achievement gap between white and URM students in an undergraduate biology course has a psychological and emotional component arising from stereotype threat. Specifically, we introduced a values affirmation exercise that counters stereotype threat by reinforcing a student’s feelings of integrity and self-worth in three iterations of an intensive active-learning college biology course. On average, this exercise reduced the achievement gap between URM and white students who entered the course with the same incoming grade point average. This result suggests that achievement gaps resulting from the underperformance of URM students could be mitigated by providing students with a learning environment that removes psychological and emotional impediments of performance through short psychosocial interventions. PMID:28710060

Optical Control of Internal Electric Fields in Band Gap-Graded InGaN Nanowires

NASA Astrophysics Data System (ADS)

Erhard, N.; Sarwar, A. T. M. Golam; Yang, F.; McComb, D. W.; Myers, R. C.; Holleitner, A. W.

2015-01-01

InGaN nanowires are suitable building blocks for many future optoelectronic devices. We show that a linear grading of the indium content along the nanowire axis from GaN to InN introduces an internal electric field evoking a photocurrent. Consistent with quantitative band structure simulations we observe a sign change in the measured photocurrent as a function of photon flux. This negative differential photocurrent opens the path to a new type of nanowire-based photodetector. We demonstrate that the photocurrent response of the nanowires is as fast as 1.5 ps.

Characterization of Cu(In,Ga)Se 2 (CIGS) films with varying gallium ratios

DOE PAGES

Claypoole, Jesse; Peace, Bernadette; Sun, Neville; ...

2015-09-05

Cu(In 1–x,Ga x)Se 2 (CIGS) absorber layers were deposited on molybdenum (Mo) coated soda-lime glass substrates with varying Ga content (described as Ga/(In + Ga) ratios) with respect to depth. As the responsible mechanisms for the limitation of the performance of the CIGS solar cells with high Ga contents are not well understood, the goal of this work was to investigate different properties of CIGS absorber films with Ga/(In + Ga) ratios varied between 0.29 and 0.41 (as determined by X-ray florescence spectroscopy (XRF)) in order to better understand the role that the Ga content has on film quality. Themore » Ga grading in the CIGS layer has the effect causing a higher band gap toward the surface and Mo contact while the band gap in the middle of the CIGS layer is lower. Also, a wider and larger Ga/(In + Ga) grading dip located deeper in the CIGS absorber layers tend to produce larger grains in the regions of the films that have lower Ga/(In + Ga) ratios. Moreover, it was found that surface roughness decreases from 51.2 nm to 41.0 nm with increasing Ga/(In + Ga) ratios. Furthermore, the surface roughness generally decreases if the Ga grading occurs deeper in the absorber layer.« less

Semiconductor-based photoelectrochemical water splitting at the limit of very wide depletion region

DOE PAGES

Liu, Mingzhao; Lyons, John L.; Yan, Danhua H.; ...

2015-11-23

In semiconductor-based photoelectrochemical (PEC) water splitting, carrier separation and delivery largely relies on the depletion region formed at the semiconductor/water interface. As a Schottky junction device, the trade-off between photon collection and minority carrier delivery remains a persistent obstacle for maximizing the performance of a water splitting photoelectrode. Here, it is demonstrated that the PEC water splitting efficiency for an n-SrTiO 3 (n-STO) photoanode is improved very significantly despite its weak indirect band gap optical absorption (α < 10⁴ cm⁻¹), by widening the depletion region through engineering its doping density and profile. Graded doped n-SrTiO 3 photoanodes are fabricated withmore » their bulk heavily doped with oxygen vacancies but their surface lightly doped over a tunable depth of a few hundred nanometers, through a simple low temperature re-oxidation technique. The graded doping profile widens the depletion region to over 500 nm, thus leading to very efficient charge carrier separation and high quantum efficiency (>70%) for the weak indirect transition. As a result, this simultaneous optimization of the light absorption, minority carrier (hole) delivery, and majority carrier (electron) transport by means of a graded doping architecture may be useful for other indirect band gap photocatalysts that suffer from a similar problem of weak optical absorption.« less

Systemic effect of mineral aggregate-based cements: histopathological analysis in rats.

PubMed

Garcia, Lucas da Fonseca Roberti; Huck, Claudia; Magalhães, Fernando Augusto Cintra; Souza, Pedro Paulo Chaves de; Souza Costa, Carlos Alberto de

2017-01-01

Several studies reported the local tissue reaction caused by mineral aggregate-based cements. However, few studies have investigated the systemic effects promoted by these cements on liver and kidney when directly applied to connective tissue. The purpose of this in vivo study was to investigate the systemic effect of mineral aggregate-based cements on the livers and kidneys of rats. Samples of Mineral Trioxide Aggregate (MTA) and a calcium aluminate-based cement (EndoBinder) containing different radiopacifiers were implanted into the dorsum of 40 rats. After 7 and 30 d, samples of subcutaneous, liver and kidney tissues were submitted to histopathological analysis. A score (0-3) was used to grade the inflammatory reaction. Blood samples were collected to evaluate changes in hepatic and renal functions of animals. The moderate inflammatory reaction (2) observed for 7 d in the subcutaneous tissue decreased with time for all cements. The thickness of inflammatory capsules also presented a significant decrease with time (P<.05). Systemically, all cements caused adverse inflammatory reactions in the liver and kidney, being more evident for MTA, persisting until the end of the analysis. Liver functions increased significantly for MTA during 30 d (P<.05). The different cements induced to a locally limited inflammatory reaction. However, from the systemic point of view, the cements promoted significant inflammatory reactions in the liver and kidney. For MTA, the reactions were more accentuated.

Expansion of 3D human induced pluripotent stem cell aggregates in bioreactors: Bioprocess intensification and scaling-up approaches.

PubMed

Abecasis, Bernardo; Aguiar, Tiago; Arnault, Émilie; Costa, Rita; Gomes-Alves, Patricia; Aspegren, Anders; Serra, Margarida; Alves, Paula M

2017-03-20

Human induced pluripotent stem cells (hiPSC) are attractive tools for drug screening and disease modeling and promising candidates for cell therapy applications. However, to achieve the high numbers of cells required for these purposes, scalable and clinical-grade technologies must be established. In this study, we use environmentally controlled stirred-tank bioreactors operating in perfusion as a powerful tool for bioprocess intensification of hiPSC production. We demonstrate the importance of controlling the dissolved oxygen concentration at low levels (4%) and perfusion at 1.3day -1 dilution rate to improve hiPSC growth as aggregates in a xeno-free medium. This strategy allowed for increased cell specific growth rate, maximum volumetric concentrations (4.7×10 6 cell/mL) and expansion factors (approximately 19 in total cells), resulting in a 2.6-fold overall improvement in cell yields. Extensive cell characterization, including whole proteomic analysis, was performed to confirm that cells' pluripotent phenotype was maintained during culture. A scalable protocol for continuous expansion of hiPSC aggregates in bioreactors was implemented using mechanical dissociation for aggregate disruption and cell passaging. A total expansion factor of 1100 in viable cells was obtained in 11days of culture, while cells maintained their proliferation capacity, pluripotent phenotype and potential as well as genomic stability after 3 sequential passages in bioreactors. Copyright © 2017 Elsevier B.V. All rights reserved.

Diatomite

USGS Publications Warehouse

Crangle, R.D.

2013-01-01

The United States continues to be the world’s leading producer and consumer of diatomite. Production of diatomite in the United States during 2012 was estimated to be 820 kt (903,000 st), a slight increase compared with 2011 production. The unit value of diatomite varied widely by end use in 2012. Diatomite used as a lightweight aggregate was priced at $11/t ($9.98/st), while specialty-grade diatomite, used in art supplies, cosmetics, or biomedical applications, could be priced as high as $10,000/t ($9,000/st). Filter-grade diatomite had an average unit value of $330/t ($299/st). Seven companies operated 10 mines and nine processing facilities in California, Nevada, Oregon and Washington. U.S. diatomite exports totaled about 96 kt (106,000 st). Imports were much lower at approximately 3.07 kt (3,380 st).

Diatomite

USGS Publications Warehouse

Crangle, R.D.

2012-01-01

The United States continues to be the world's leading producer and consumer of diatomite. Production of diatomite in the United States during 2011 was estimated to be 600 kt (661,000 st), a slight increase compared with 2010 production. The unit value of diatomite varied widely by end use in 2011. Diatomite used as a lightweight aggregate was priced at $8.82/t ($8/st), while specialty-grade diatomite, used in art supplies, cosmetics, or biomedical applications, was priced as high as $10,000/t ($9,070/st) on a spot basis. Filter-grade diatomite had an average unit value of $394/t ($357/st). Seven companies operated 10 mines an nine processing facilities in California, Nevada, Oregon and Washington. U.S. diatomite exports totaled about 120 kt (132,000 st). Imports were much lower, at approximately 1 kt (1,100 st).

A measure of knowledge flow between specific fields: Implications of interdisciplinarity for impact and funding

PubMed Central

Solomon, Gregg E. A.; Youtie, Jan; Porter, Alan L.

2017-01-01

Encouraging knowledge flow between mutually relevant disciplines is a worthy aim of research policy makers. Yet, it is less clear what types of research promote cross-disciplinary knowledge flow and whether such research generates particularly influential knowledge. Empirical questions remain as to how to identify knowledge-flow mediating research and how to provide support for this research. This study contributes to addressing these gaps by proposing a new way to identify knowledge-flow mediating research at the individual research article level, instead of at more aggregated levels. We identify journal articles that link two mutually relevant disciplines in three ways—aggregating, bridging, and diffusing. We then examine the likelihood that these papers receive subsequent citations or have funding acknowledgments. Our case study of cognitive science and educational research knowledge flow suggests that articles that aggregate knowledge from multiple disciplines are cited significantly more often than are those whose references are drawn primarily from a single discipline. Interestingly, the articles that meet the criteria for being considered knowledge-flow mediators are less likely to reflect funding, based on reported acknowledgements, than were those that did not meet these criteria. Based on these findings, we draw implications for research policymakers. PMID:29016631

Directional virtual backbone based data aggregation scheme for Wireless Visual Sensor Networks.

PubMed

Zhang, Jing; Liu, Shi-Jian; Tsai, Pei-Wei; Zou, Fu-Min; Ji, Xiao-Rong

2018-01-01

Data gathering is a fundamental task in Wireless Visual Sensor Networks (WVSNs). Features of directional antennas and the visual data make WVSNs more complex than the conventional Wireless Sensor Network (WSN). The virtual backbone is a technique, which is capable of constructing clusters. The version associating with the aggregation operation is also referred to as the virtual backbone tree. In most of the existing literature, the main focus is on the efficiency brought by the construction of clusters that the existing methods neglect local-balance problems in general. To fill up this gap, Directional Virtual Backbone based Data Aggregation Scheme (DVBDAS) for the WVSNs is proposed in this paper. In addition, a measurement called the energy consumption density is proposed for evaluating the adequacy of results in the cluster-based construction problems. Moreover, the directional virtual backbone construction scheme is proposed by considering the local-balanced factor. Furthermore, the associated network coding mechanism is utilized to construct DVBDAS. Finally, both the theoretical analysis of the proposed DVBDAS and the simulations are given for evaluating the performance. The experimental results prove that the proposed DVBDAS achieves higher performance in terms of both the energy preservation and the network lifetime extension than the existing methods.

Exciton-Induced Degradation of Carbazole-Based Host Materials and Its Role in the Electroluminescence Spectral Changes in Phosphorescent Organic Light Emitting Devices with Electrical Aging.

PubMed

Yu, Hyeonghwa; Zhang, Yingjie; Cho, Yong Joo; Aziz, Hany

2017-04-26

We investigate the origins of the long-wavelength bands that appear in the emission spectra of carbazole-based host materials and play a role in the electroluminescence (EL) spectral changes of phosphorescent organic light emitting devices (PhOLEDs) with electrical aging. 4,4'-Bis(carbazol-9-yl)biphenyl (CBP) is used as a model carbazole host material and is studied using photoluminescence, EL, and atomic force microscopy measurements under various stress scenarios in both single and bilayer devices and in combination with various electron transport layer (ETL) materials. Results show that exciton-induced morphological aggregation of CBP is behind the appearance of those long-wavelength bands and that complexation between the aggregated CBP molecules and ETL molecules plays a role in this phenomenon. Comparisons between the effects of exciton and thermal stress suggest that exciton-induced aggregation may be limited to short-range molecular ordering or pairing (e.g., dimer or trimer species formation) versus longer-range ordering (crystallization) in the case of thermal stress. The findings provide new insights into exciton-induced degradation in wide band gap host materials and its role in limiting the stability of PhOLEDs.

Predictors of introduction success in the South Florida avifauna

USGS Publications Warehouse

Allen, Craig R.

2006-01-01

Biological invasions are an increasing global challenge, for which single-species studies and analyses focused on testing single hypotheses of causation in isolation are unlikely to provide much additional insight. Species interact with other species to create communities, which derive from species interactions and from the interactions of species with the scale specific elements of the landscape that provide suitable habitat and exploitable resources. I used logistic regression analysis to sort among potential intrinsic, community and landscape variables that theoretically influence introduction success. I utilized the avian fauna of the Everglades of South Florida, and the variables body mass, distance to nearest neighbor (in terms of body mass), year of introduction, presence of congeners, guild membership, continent of origin, distribution in a body mass aggregation or gap, and distance to body-mass aggregation edge (in terms of body mass). Two variables were significant predictors of introduction success. Introduced avian species whose body mass placed them nearer to a body-mass aggregation edge and further from their neighbor were more likely to become successfully established. This suggests that community interactions, and community level phenomena, may be better understood by explicitly incorporating scale. ?? Springer 2006.

Nonlocal grazing in patterned ecosystems.

PubMed

Siero, E

2018-01-07

Many ecosystems exhibit gapped, labyrinthine, striped or spotted patterns. Important examples are vegetation patterns in drylands: these patterns are viewed as precursors of a catastrophic transition to a degraded state. A possible source of degradation is overgrazing, but many current spatially extended models include grazing in a local linear way. In this article nonlocal grazing responses are derived, taking into account (1) how many consumers there are (demographic response) (2) where they are (aggregative response) and (3) how much they forage (functional response). Different assumptions lead to different grazing responses, the type of grazing has a large influence on how ecosystems adapt to changing environmental conditions. In dryland simulations the different types of grazing are shown to alter the desertification process driven by decreasing rainfall. A sufficiently strong aggregative response leads to the suppression of vegetation patterns, nuancing their role as generic early warning signals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soil Organic Matter (SOM): Molecular Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andersen, Amity

Molecular simulation is a powerful tool used to gain an atomistic, molecular, and nanoscale level understanding of the structure, dynamics, and interactions from adsorption on minerals and assembly in aggregates of soil organic matter (SOM). Given the importance of SOM fate and persistence in soils and the current knowledge gaps, applications of atomistic scale simulations to study the complex compounds in SOM and their interactions in self-assembled aggregates composed of different organic matter compounds and with mineral surfaces of different types common in soils are few and far between. Here, we describe various molecular simulation methods that are currently inmore » use in various areas and applicable to SOM research, followed by a brief survey of specific applications to SOM research and an illustration with our own recent efforts in this area. We conclude with an outlook and the challenges for future research in this area.« less

Ultra-High Aggregate Bandwidth Two-Dimensional Multiple-Wavelength Diode Laser Arrays

DTIC Science & Technology

1993-12-09

during the growth of the cavity spacer region using the fact that the molecular beam epitaxy growth of GaAs is highly sensitive to the substrate... molecular beam epitaxy (MBE) crystal growth, the GaAs growth rate is highly sensitive to the substrate temperature above 650"C (2], a GaAs/AIGaAs... epitaxial growth technique to make reproducible and repeatable multi-wavelength VCSEL arrays. Our approach to fabricate the spatially graded layer

Composition-graded nanowire solar cells fabricated in a single process for spectrum-splitting photovoltaic systems.

PubMed

Caselli, Derek; Liu, Zhicheng; Shelhammer, David; Ning, Cun-Zheng

2014-10-08

Nanomaterials such as semiconductor nanowires have unique features that could enable novel optoelectronic applications such as novel solar cells. This paper aims to demonstrate one such recently proposed concept: Monolithically Integrated Laterally Arrayed Multiple Band gap (MILAMB) solar cells for spectrum-splitting photovoltaic systems. Two cells with different band gaps were fabricated simultaneously in the same process on a single substrate using spatially composition-graded CdSSe alloy nanowires grown by the Dual-Gradient Method in a chemical vapor deposition system. CdSSe nanowire ensemble devices tested under 1 sun AM1.5G illumination achieved open-circuit voltages up to 307 and 173 mV and short-circuit current densities as high as 0.091 and 0.974 mA/cm(2) for the CdS- and CdSe-rich cells, respectively. The open-circuit voltages were roughly three times those of similar CdSSe film cells fabricated for comparison due to the superior optical quality of the nanowires. I-V measurements were also performed using optical filters to simulate spectrum-splitting. The open-circuit voltages and fill factors of the CdS-rich subcells were uniformly larger than the corresponding CdSe-rich cells for similar photon flux, as expected. This suggests that if all wires can be contacted, the wide-gap cell is expected to have greater output power than the narrow-gap cell, which is the key to achieving high efficiencies with spectrum-splitting. This paper thus provides the first proof-of-concept demonstration of simultaneous fabrication of MILAMB solar cells. This approach to solar cell fabrication using single-crystal nanowires for spectrum-splitting photovoltaics could provide a future low-cost high-efficiency alternative to the conventional high-cost high-efficiency tandem cells.

Widespread epigenomic, transcriptomic and proteomic differences between hip osteophytic and articular chondrocytes in osteoarthritis.

PubMed

Steinberg, Julia; Brooks, Roger A; Southam, Lorraine; Bhatnagar, Sahir; Roumeliotis, Theodoros I; Hatzikotoulas, Konstantinos; Zengini, Eleni; Wilkinson, J Mark; Choudhary, Jyoti S; McCaskie, Andrew W; Zeggini, Eleftheria

2018-05-08

To identify molecular differences between chondrocytes from osteophytic and articular cartilage tissue from OA patients. We investigated genes and pathways by combining genome-wide DNA methylation, RNA sequencing and quantitative proteomics in isolated primary chondrocytes from the cartilaginous layer of osteophytes and matched areas of low- and high-grade articular cartilage across nine patients with OA undergoing hip replacement surgery. Chondrocytes from osteophytic cartilage showed widespread differences to low-grade articular cartilage chondrocytes. These differences were similar to, but more pronounced than, differences between chondrocytes from osteophytic and high-grade articular cartilage, and more pronounced than differences between high- and low-grade articular cartilage. We identified 56 genes with significant differences between osteophytic chondrocytes and low-grade articular cartilage chondrocytes on all three omics levels. Several of these genes have known roles in OA, including ALDH1A2 and cartilage oligomeric matrix protein, which have functional genetic variants associated with OA from genome-wide association studies. An integrative gene ontology enrichment analysis showed that differences between osteophytic and low-grade articular cartilage chondrocytes are associated with extracellular matrix organization, skeletal system development, platelet aggregation and regulation of ERK1 and ERK2 cascade. We present a first comprehensive view of the molecular landscape of chondrocytes from osteophytic cartilage as compared with articular cartilage chondrocytes from the same joints in OA. We found robust changes at genes relevant to chondrocyte function, providing insight into biological processes involved in osteophyte development and thus OA progression.

Modified Treatment Algorithm for Pseudogynecomastia After Massive Weight Loss.

PubMed

Ziegler, Ulrich E; Lorenz, Udo; Daigeler, Adrien; Ziegler, Selina N; Zeplin, Philip H

2018-06-19

Pseudogynecomastia is the increased aggregation of fatty tissue in the area of the male breast with resultant female appearance. Two forms can appear: pseudogynecomastia after massive weight loss (pseudogynecomastia obese [PO]) and pseudogynecomastia, which is caused only by adipose tissue (pseudogynecomastia fat). For PO, only the Gusenoff classification with corresponding operative treatment options exists. However, this classification is limited by the fact that it underestimates the extensive variability of residual fat tissue and skin excess, both crucial factors for operative planning. For this reason, we propose a modification of the treatment algorithm for the Gusenoff classification based on our results to achieve more masculine results. A total of 43 male patients with PO were included in this retrospective study (grade 1a, n = 1; grade 1b, n = 1; grade 2, n = 17; grade 3, n = 24). Forty-two mastectomies with a free nipple-areola complex (NAC) transposition (grades 2 and 3) and 1 with a subcutaneous mastectomy (grade 1a) with periareolar lifting were performed. A retrospective chart review was performed to obtain data regarding age, body mass index, body mass index loss, weight loss, reason for weight loss, comorbidities, nicotine, and additional procedures, postoperative sensitive on the NAC transplants and complications. None of the free-nipple grafts were lost. Forty (95%) of 42 patients with mastectomy had a resensitivity on the NAC. For pseudogynecomastia, the treatment algorithm of the Gusenoff classification should be modified and adapted according to our recommendations to achieve more optimal masculine results.

Culturally Responsive Teaching in an Oglala Lakota Classroom

ERIC Educational Resources Information Center

Stowe, Rebeka

2017-01-01

In response to the widening academic achievement gap between Native American students and other students in the United States, a culturally responsive approach was used in a Native American social studies class with positive results. Eighth-grade Oglala Lakota students in an American History classroom experienced a unit infused with lessons that…

The Influence of Academic Momentum and Associate Degree Credit Requirements on Community College Student Degree Completion

ERIC Educational Resources Information Center

Knox, Daniel

2017-01-01

This study addresses gaps in the theoretical and policy literature by examining the relationship between associate degree program credit requirements and four student outcomes: associate degree attainment, time to degree, final associate degree grade point average, and persistence. Using student unit record data, a longitudinal quantitative study…

Do Interim Assessments Reduce the Race and SES Achievement Gaps?

ERIC Educational Resources Information Center

Konstantopoulos, Spyros; Li, Wei; Miller, Shazia R.; van der Ploeg, Arie

2017-01-01

The authors examined differential effects of interim assessments on minority and low socioeconomic status students' achievement in Grades K-6. They conducted a large-scale cluster randomized experiment in 2009-2010 to evaluate the impact of Indiana's policy initiative introducing interim assessments statewide. The authors used 2-level models to…

Oral Vocabulary and Language Acquisition Strategies to Increase Literacy

ERIC Educational Resources Information Center

Green, Grace

2017-01-01

This study addresses low literacy achievement in students in kindergarten and first grades. The study was designed to help identify how general education teachers can use specific daily research-based oral vocabulary acquisition strategies to close the literacy gap. This quantitative research helped to determine if the implementation of an oral…

Level 2 Therapeutic Model Site

ERIC Educational Resources Information Center

Spears, Brad; Sanchez, David; Bishop, Jane; Rogers, Sharon; DeJong, Judith A.

2006-01-01

L2, one of the original sites first funded under the Therapeutic Residential Model Initiative in 2001-2002, is operated as a peripheral dormitory This dormitory cares for 185 boys and girls in grades 1-12 who attend local public schools. L2 presented an outstanding proposal which identified gaps in services and presented a reasonable budget to…

Helping Students Adapt to Graduate School: Making the Grade.

ERIC Educational Resources Information Center

Silber, Earle; Arnstein, Robert L.; Backus, Varda; Eddy, Harrison P.; Liptzin, Myron B.; Notman, Malkah Tolpin; Reich, Peter; Reid, Elizabeth Aub; Siggins, Lorraine D.; Silverman, Morton; Stauffer, Tom G.; Wenger, Robert E.

This book, formulated by the Group for the Advancement of Psychiatry (GAP) Committee on the College Student, describes the complexity of graduate student lives and advocates providing students with mental health services and other support to help them cope more successfully with the challenges of graduate school. It provides a view of students…

Teaching and Reaching All Students: An Instructional Model for Closing the Gap

ERIC Educational Resources Information Center

Powell, Rebecca; Cantrell, Susan Chambers; Rightmyer, Elizabeth

2013-01-01

This article presents a model for culturally responsive instruction (CRI) that represents a synthesis of research on effective literacy and content instruction for diverse middle grades learners.The article discusses the various elements of the Culturally Responsive Instruction Observation Protocol (CRIOP) model. It then examines these elements by…

Use of Angle Model to Understand Addition and Subtraction of Fractions

ERIC Educational Resources Information Center

Mukwambo, Muzwangowenyu; Ngcoza, Kenneth; Ramasike, Lineo Florence

2018-01-01

Learners in lower primary and even some in upper primary grades grapple to perform mathematical operations which involve fractions. Failure to solve these mathematical operations creates a gap in the teaching and learning processes of mathematics. We opine that this is attributed to use of traditional mathematical approaches of teaching and…

"Scrubbing" Data for D3M

ERIC Educational Resources Information Center

Mercurius, Neil

2005-01-01

Data-driven decision-making (D3M) appears to be the new buzz phrase for this century, the information age. On the education front, teachers and administrators are engaging in data-centered dialog in grade-level meetings, lounges, hallways, and classrooms as they brainstorm toward closing the gap in student achievement. Clearly, such discussion…

High power RF coaxial switch

NASA Technical Reports Server (NTRS)

Caro, E. R. (Inventor)

1980-01-01

A coaxial switch capable of operating in a vacuum with high RF power in the 1.2 GHz range without multipactor breakdown, and without relying on pressurization with an inert gas is described. The RF carrying conductors of the switch are surrounded with a high grade solid dielectric, thus eliminating any gaps in which electrons can accelerate.

Making the Grade: A 50-State Analysis of School Accountability Systems.

ERIC Educational Resources Information Center

Martin, Carmel; Sargrad, Scott; Batel, Samantha

2016-01-01

One of the most enduring and contentious debates in education circles concerns the best way to hold schools and districts accountable for improving outcomes for students and closing achievement gaps. Lawmakers, teachers, district administrators, parents, and other stakeholders--all with strong and differing opinions--have wrestled for decades with…

One Community Working Together

ERIC Educational Resources Information Center

Weis, Charles

2011-01-01

In the city of San Jose, more than half of all public school students tested are not proficient in their grade-level skills. This article discusses how school, civic and community leaders have joined forces with the goal of eliminating the achievement gap in San Jose by 2020. This wide and highly inclusive collaboration is made possible by an…

Analyzing Algebraic Thinking Using "Guess My Number" Problems

ERIC Educational Resources Information Center

Patton, Barba; De Los Santos, Estella

2012-01-01

The purpose of this study was to assess student knowledge of numeric, visual and algebraic representations. A definite gap between arithmetic and algebra has been documented in the research. The researchers' goal was to identify a link between the two. Using four "Guess My Number" problems, seventh and tenth grade students were asked to write…

Educators' Perceptions of Teaching Grade-Level Content to Students with Intellectual Disabilities

ERIC Educational Resources Information Center

Carlson, Christina V.

2016-01-01

The purpose of this study was to address a gap in the research literature by describing the perceptions of Special Education teachers of students with intellectual disabilities (ID), regarding the paradigm shift required in their teaching practices as they strove to implement current educational reform legislation. Knowledge of the lived…

On Being Aware and Accepting: A One-Year Longitudinal Study into Adolescent Well-Being

ERIC Educational Resources Information Center

Ciarrochi, Joseph; Kashdan, Todd B.; Leeson, Peter; Heaven, Patrick; Jordan, Carlie

2011-01-01

The nature and potential benefit of awareness and experiential acceptance in adolescence remains neglected and understudied. To address this gap in the literature, 776 students (50% female) in Grade 10 completed measures of mindfulness, emotional awareness, and experiential acceptance, as well as measures of major personality traits. To study…

A Value-Added Study of a Federal Grant Program in Mathematics for Military Dependent Students

ERIC Educational Resources Information Center

Marquand, Jay C.

2013-01-01

Closing the achievement gap in public education means all students are expected to be learning at grade level. In response to federal mandates requiring schools to attain specific student achievement benchmarks, many schools are placing greater resources into support programs designed to increase student achievement. Military dependent students…

Minding the Gap: Children's Difficulty Conceptualizing Spatial Intervals as Linear Measurement Units

ERIC Educational Resources Information Center

Solomon, Tracy L.; Vasilyeva, Marina; Huttenlocher, Janellen; Levine, Susan C.

2015-01-01

Understanding measurement units is critical to mathematics and science learning, but it is a topic that American students find difficult. In 3 studies, we investigated the challenges underlying this difficulty in kindergarten and second grade by comparing performance on different versions of a linear measurement task. Children measured crayons…

School Districts and Student Achievement

ERIC Educational Resources Information Center

Chingos, Matthew M.; Whitehurst, Grover J.; Gallaher, Michael R.

2015-01-01

School districts are a focus of education reform efforts in the United States, but there is very little existing research about how important they are to student achievement. We fill this gap in the literature using 10 years of student-level, statewide data on fourth- and fifth-grade students in Florida and North Carolina. A variance decomposition…

Building and Activating Students' Background Knowledge: It's What They Already Know That Counts

ERIC Educational Resources Information Center

Fisher, Douglas; Frey, Nancy; Lapp, Diane

2012-01-01

Students enter the middle grades with varying amounts of background knowledge. Teachers must assess student background knowledge for gaps or misconceptions and then provide instruction to build on that base. This article discusses effective strategies for assessing and developing students' background knowledge so they can become independent…

Technology-Enhanced Multimedia Instruction in Foreign Language Classrooms: A Mixed Methods Study

ERIC Educational Resources Information Center

Ketsman, Olha

2012-01-01

Technology-enhanced multimedia instruction in grades 6 through 12 foreign language classrooms was the focus of this study. The study's findings fill a gap in the literature through the report of how technology-enhanced multimedia instruction was successfully implemented in foreign language classrooms. Convergent parallel mixed methods study…

Dyslexia Training Program. What Works Clearinghouse Intervention Report

ERIC Educational Resources Information Center

What Works Clearinghouse, 2010

2010-01-01

The "Dyslexia Training Program," developed at the Texas Scottish Rite Hospital for Children, is a Tier III reading intervention program that provides intensive phonics instruction to children with dyslexia, primarily in grades two through five. It is a comprehensive two-year program that bridges the gap for school districts in which a…

Teaching the Teachers

ERIC Educational Resources Information Center

Kronholz, June

2012-01-01

Data-driven instruction began its spread across the country about a decade ago, in the footsteps of the No Child Left Behind requirement that schools administer yearly achievement tests. Those tests didn't help teachers spot and backfill learning gaps, though. Scores came back after everyone had moved on to the next grade, and anyway, the tests…

A Critical Review of the Massachusetts Next Generation Science and Technology/Engineering Standards. Policy Brief

ERIC Educational Resources Information Center

Metzenberg, Stan

2015-01-01

Stan Metzenberg offers a critical analysis of the draft "Massachusetts Science and Technology/Engineering Standards," which are for pre-Kindergarten to Grade 8 and introductory high school courses. Metzenberg claims that the document reveals significant, unacceptable gaps in science content, as well as some notable errors and…

Kindergarten Readiness in Wisconsin. WCER Working Paper No. 2017-3

ERIC Educational Resources Information Center

Grodsky, Eric; Yiyue, Huangfu,; Miesner, H. Rose; Packard, Chiara

2017-01-01

Wisconsin's gaps between Black and White student high school graduation rates (Richards, 2016) and Black and White fourth-grade math and reading scores (U.S. Department of Education, 2015) are the largest in the nation. These inequalities have led to criticisms of Wisconsin's schools and teachers as ineffective in bolstering the success of…

The Contributions of Oral and Silent Reading Fluency to Reading Comprehension

ERIC Educational Resources Information Center

Price, Katherine W.; Meisinger, Elizabeth B.; Louwerse, Max M.; D'Mello, Sidney

2016-01-01

Silent reading fluency has received limited attention in the school-based literatures across the past decade. We fill this gap by examining both oral and silent reading fluency and their relation to overall abilities in reading comprehension in fourth-grade students. Lower-level reading skills (word reading, rapid automatic naming) and vocabulary…

102. Catalog HHistory 1, C.C.C., 34 Landscaping, Negative No. 6040a ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

102. Catalog H-History 1, C.C.C., 34 Landscaping, Negative No. 6040a (Photographer and date unknown) BEAUTIFICATION PROGRAM STARTED AS SOON AS GRADING ALONG THE DRIVE WAS COMPLETED. CCC CAMP 3 SHOWN PLANTING LAUREL. - Skyline Drive, From Front Royal, VA to Rockfish Gap, VA , Luray, Page County, VA

Lessons Learned: Collaborative Symbiosis and Responsive Disciplinary Literacy Teaching

ERIC Educational Resources Information Center

Wilder, Phillip; Herro, Danielle

2016-01-01

This paper describes a case study of how a middle school literacy coach and a science teacher attempted to improve disciplinary literacy teaching in a sixth-grade science class. The collaborative inquiry exposed the disciplinary knowledge gap of the literacy coach (a former language arts teacher) and the science teacher's limited knowledge of…

Examination of Achievement Gaps among Fourth Grade Students in a Selected Louisiana School District

ERIC Educational Resources Information Center

LeJeune, Kevin Scott

2010-01-01

A major concern for educators is that student achievement is disproportionate and not increasing for all groups at the same rate. This applied dissertation addressed the problem of unequal achievement for African American, economically disadvantaged, and academically at-risk students. This quantitative study utilized a correlational design to…

Female Teachers, Whiteness, and the Quest for Cultural Proficiency

ERIC Educational Resources Information Center

Jayne, Ann M.

2014-01-01

Though America's public schools have become increasingly diverse, the teaching staff remains relatively homogeneous. This gap is more apparent in California schools that serve large numbers of students of color, being taught by teachers who are predominately White and female. Because the population of kindergarten-through-12th-grade teachers is…

Gaps between Beliefs, Perceptions, and Practices: The Every Teacher Project on LGBTQ-Inclusive Education in Canadian Schools

ERIC Educational Resources Information Center

Taylor, Catherine G.; Meyer, Elizabeth J.; Peter, Tracey; Ristock, Janice; Short, Donn; Campbell, Christopher

2016-01-01

The Every Teacher Project involved large-scale survey research conducted to identify the beliefs, perspectives, and practices of Kindergarten to Grade 12 educators in Canadian public schools regarding lesbian, gay, bisexual, transgender, and queer (LGBTQ)-inclusive education. Comparisons are made between LGBTQ and cisgender heterosexual…

Closing the Achievement Gap through Modification of Neurocognitive and Neuroendocrine Function: Results from a Cluster Randomized Controlled Trial of an Innovative Approach to the Education of Children in Kindergarten

PubMed Central

Blair, Clancy; Raver, C. Cybele

2014-01-01

Effective early education is essential for academic achievement and positive life outcomes, particularly for children in poverty. Advances in neuroscience suggest that a focus on self-regulation in education can enhance children’s engagement in learning and establish beneficial academic trajectories in the early elementary grades. Here, we experimentally evaluate an innovative approach to the education of children in kindergarten that embeds support for self-regulation, particularly executive functions, into literacy, mathematics, and science learning activities. Results from a cluster randomized controlled trial involving 29 schools, 79 classrooms, and 759 children indicated positive effects on executive functions, reasoning ability, the control of attention, and levels of salivary cortisol and alpha amylase. Results also demonstrated improvements in reading, vocabulary, and mathematics at the end of kindergarten that increased into the first grade. A number of effects were specific to high-poverty schools, suggesting that a focus on executive functions and associated aspects of self-regulation in early elementary education holds promise for closing the achievement gap. PMID:25389751

Closing the achievement gap through modification of neurocognitive and neuroendocrine function: results from a cluster randomized controlled trial of an innovative approach to the education of children in kindergarten.

PubMed

Blair, Clancy; Raver, C Cybele

2014-01-01

Effective early education is essential for academic achievement and positive life outcomes, particularly for children in poverty. Advances in neuroscience suggest that a focus on self-regulation in education can enhance children's engagement in learning and establish beneficial academic trajectories in the early elementary grades. Here, we experimentally evaluate an innovative approach to the education of children in kindergarten that embeds support for self-regulation, particularly executive functions, into literacy, mathematics, and science learning activities. Results from a cluster randomized controlled trial involving 29 schools, 79 classrooms, and 759 children indicated positive effects on executive functions, reasoning ability, the control of attention, and levels of salivary cortisol and alpha amylase. Results also demonstrated improvements in reading, vocabulary, and mathematics at the end of kindergarten that increased into the first grade. A number of effects were specific to high-poverty schools, suggesting that a focus on executive functions and associated aspects of self-regulation in early elementary education holds promise for closing the achievement gap.

Reducing the gender achievement gap in college science: a classroom study of values affirmation.

PubMed

Miyake, Akira; Kost-Smith, Lauren E; Finkelstein, Noah D; Pollock, Steven J; Cohen, Geoffrey L; Ito, Tiffany A

2010-11-26

In many science, technology, engineering, and mathematics disciplines, women are outperformed by men in test scores, jeopardizing their success in science-oriented courses and careers. The current study tested the effectiveness of a psychological intervention, called values affirmation, in reducing the gender achievement gap in a college-level introductory physics class. In this randomized double-blind study, 399 students either wrote about their most important values or not, twice at the beginning of the 15-week course. Values affirmation reduced the male-female performance and learning difference substantially and elevated women's modal grades from the C to B range. Benefits were strongest for women who tended to endorse the stereotype that men do better than women in physics. A brief psychological intervention may be a promising way to address the gender gap in science performance and learning.

The impact of a developmental science course on college success for underprepared health science students

NASA Astrophysics Data System (ADS)

Johnson, Candace A.

Developmental education for the academically underprepared college student has been aimed at helping students succeed in college. However, developmental education courses have traditionally focused on reading, writing and math. This quantitative study examined the relationship between a developmental science course for underprepared health science students on grades achieved in college level medical terminology courses. The effect was measured by analyzing student grades retrieved from a college database of official school records through the use of correlation research methodology during a previous 2-year academic period at a selected independent 4-year right-to-try college. The results yielded a weakly positive correlation, but not statistically significant coefficient of 0.325 between grades for students who successfully completed the developmental science course and their subsequent success in a college-level science course. The study added to the gap in knowledge in terms of the effect a developmental science course has on grades in college-level science courses.

High temperature stability of anatase in titania-alumina semiconductors with enhanced photodegradation of 2, 4-dichlorophenoxyacetic acid.

PubMed

López-Granada, G; Barceinas-Sánchez, J D O; López, R; Gómez, R

2013-12-15

The incorporation of aluminum acetylacetonate as alumina source during the gelation of titanium alkoxide reduces the nucleation sites for the formation of large rutile crystals on temperatures ranging from 400 to 800°C. As a result, the aggregation of anatase crystals is prevented at high temperature. A relationship among the specific surface area, pore size, energy band gap, crystalline structure and crystallite size as the most relevant parameters are evaluated and discussed. According to the results for the photocatalytic degradation of 2,4-dichlorophenoxyacetic acid, the specific surface area, pore size, Eg band gap are not determinant in the photocatalytic properties. It was found that the anatase crystallite size is the mores important parameter affecting the degradation efficiency. Copyright © 2013 Elsevier B.V. All rights reserved.

DUST COAGULATION IN THE VICINITY OF A GAP-OPENING JUPITER-MASS PLANET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carballido, Augusto; Matthews, Lorin S.; Hyde, Truell W., E-mail: Augusto_Carballido@baylor.edu

We analyze the coagulation of dust in and around a gap opened by a Jupiter-mass planet. To this end, we carry out a high-resolution magnetohydrodynamic (MHD) simulation of the gap environment, which is turbulent due to the magnetorotational instability. From the MHD simulation, we obtain values of the gas velocities, densities, and turbulent stresses (a) close to the gap edge, (b) in one of the two gas streams that accrete onto the planet, (c) inside the low-density gap, and (d) outside the gap. The MHD values are then input into a Monte Carlo dust-coagulation algorithm which models grain sticking andmore » compaction. We also introduce a simple implementation for bouncing, for comparison purposes. We consider two dust populations for each region: one whose initial size distribution is monodisperse, with monomer radius equal to 1 μ m, and another one whose initial size distribution follows the Mathis–Rumpl–Nordsieck distribution for interstellar dust grains, with an initial range of monomer radii between 0.5 and 10 μ m. Without bouncing, our Monte Carlo calculations show steady growth of dust aggregates in all regions, and the mass-weighted (m-w) average porosity of the initially monodisperse population reaches extremely high final values of 98%. The final m-w porosities in all other cases without bouncing range between 30% and 82%. The efficiency of compaction is due to high turbulent relative speeds between dust particles. When bouncing is introduced, growth is slowed down in the planetary wake and inside the gap. Future studies will need to explore the effect of different planet masses and electric charge on grains.« less

Systematic analysis underlying the quality of the scientific evidence and conflicts of interest in gastroenterology practice guidelines.

PubMed

Feuerstein, Joseph D; Gifford, Anne E; Akbari, Mona; Goldman, Jonathan; Leffler, Daniel A; Sheth, Sunil G; Cheifetz, Adam S

2013-11-01

The practice guidelines published by the American Gastroenterological Association (AGA) and the American College of Gastroenterology (ACG) are used to establish standards of care and improve patient outcomes. We examined the guidelines for quality of evidence, methods of grading evidence, and conflicts of interest (COIs). All 81 (AGA and ACG) guidelines available online on 26 July 2012 were reviewed for the presence of grading of evidence and COIs. In total, 570 recommendations were evaluated for level of evidence and methods used to grade the evidence. The data were evaluated in aggregate and by society. Only 31% (n=25) of the guidelines graded the levels of evidence. A total of 12 systems were used to grade the quality of evidence in these 25 guidelines. Of the 570 recommendations reviewed, only 29% (n=165) were supported by the highest quality of evidence, level A; 37% (n=210) level B, 29% (n=165) level C, and 5% (n=30) level D. Since 2007, 87% (n=13/15) of the ACG guidelines graded the evidence compared with only 33% of the AGA guidelines (n=4/12). Furthermore, 70% (n=57/81) of the guidelines failed to disclose any information regarding COIs. Of the 24 articles commenting on COIs, 67% reported COIs. Although the majority of the gastroenterology guidelines fail to grade the quality of evidence, more recent ACG guidelines grade majority of their recommendations. When the evidence is graded, most of the supporting evidence is based on lower-quality evidence. In addition, most of the guidelines fail to comment on COIs, and when disclosed, numerous COIs were present. This study highlights the critical need to revise the guideline development process. Future guidelines should clearly state the quality of evidence for their recommendations, utilize a standard grading system, and be transparent regarding all COIs.

Use of recycled aggregates from construction and demolition waste in geotechnical applications: A literature review.

PubMed

Cardoso, Rafaela; Silva, Rui Vasco; Brito, Jorge de; Dhir, Ravindra

2016-03-01

The use of recycled aggregates (RA) in construction constitutes a significant step towards a more sustainable society and also creates a new market opportunity to be exploited. In recent years, several case-studies have emerged in which RA were used in Geotechnical applications, such as filling materials and in unbound pavement layers. This paper presents a review of the most important physical properties of different types of RA and their comparison with natural aggregates (NA), and how these properties affect their hydraulic and mechanical behaviour when compacted. Specifically, the effects of compaction on grading size distribution curves and density are analysed, as well as the consequences of particle crushing on the resilient modulus, CBR and permeability. The paper also contains an analysis of the influence of incorporating different RA types on the performance of unbound road pavement layers as compared with those built with NA by means of the International Roughness Index and deflection values. The results collected from the literature indicate that the performance of most RA is comparable to that of NA and can be used in unbound pavement layers or in other applications requiring compaction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mineral resource potential map of the James River Face Wilderness, Bedford and Rockbridge counties, Virginia

USGS Publications Warehouse

Brown, C. Erwin; Gazdik, Gertrude C.

1982-01-01

The rocks in the James River Face Wilderness are shales and quartzites that overlie a meta-igneous basement. They are folded into a large southwestward-plunging anticline that is cut off on the east and south by an extensive thrust fault that brings old basement rocks over the younger sedimentary rocks. Geochemical studies of stream sediments, soils, and rocks do not reveal any unusually high metal concentrations, but a large resource of metallurgical-grade quartzite and shale suitable for structural clay products and lightweight aggregate is in the wilderness. Antietam (Erwin) Quartzite has been quarried at three sites in the wilderness as raw material for silicon used in the manufacture of ferrosilicon. Other uses included crushed rock for concrete aggregate, road metal, and railroad ballast, and sand for cement and mortar. Potential uses include ganister for silica brick and specialty sands such as filter and furnace sand. Firing tests on samples of shale from the Harpers (Hampton) Formation show that it could be used for the manufacture of brick and as lightweight aggregate. Of marginal economic interest are heavy-mineral layers in the basal Unicoi (Weverton) Formation.

The effect of carbon nanotubes functionalization on the band-gap energy of TiO2-CNT nanocomposite

NASA Astrophysics Data System (ADS)

Shahbazi, Hessam; Shafei, Alireza; Sheibani, Saeed

2018-01-01

In this paper the morphology and structure of TiO2-CNT nanocomposite powder obtained by an in situ sol-gel process were investigated. The synthesized nanocomposite powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and diffuse reflectance spectroscopy (DRS). The effect of functionalizing of CNT on the properties was studied. XRD results showed amorphous structure before calcination. Also, anatase phase TiO2 was formed after calcination at 400 °C. The SEM results indicate different distributions of TiO2 on CNTs. As a result, well dispersed TiO2 microstructure on the surface of CNTs was observed after functionalizing, while compact and large aggregated particles were found without functionalizing. The average thickness of uniform and well-defined coated TiO2 layer was in the range of 30-40 nm. The DRS results have determined the reflective properties and band gap energies of nanocomposite powders and have shown that functionalizing of CNTs caused the change of band-gap energy from 2.98 to 2.87 eV.

Height, selected genetic markers and prostate cancer risk: results from the PRACTICAL consortium.

PubMed

Lophatananon, Artitaya; Stewart-Brown, Sarah; Kote-Jarai, Zsofia; Olama, Ali Amin Al; Garcia, Sara Benlloch; Neal, David E; Hamdy, Freddie C; Donovan, Jenny L; Giles, Graham G; Fitzgerald, Liesel M; Southey, Melissa C; Pharoah, Paul; Pashayan, Nora; Gronberg, Henrik; Wiklund, Fredrik; Aly, Markus; Stanford, Janet L; Brenner, Hermann; Dieffenbach, Aida K; Arndt, Volker; Park, Jong Y; Lin, Hui-Yi; Sellers, Thomas; Slavov, Chavdar; Kaneva, Radka; Mitev, Vanio; Batra, Jyotsna; Spurdle, Amanda; Clements, Judith A; Easton, Douglas; Eeles, Rosalind A; Muir, Kenneth

2017-08-22

Evidence on height and prostate cancer risk is mixed, however, recent studies with large data sets support a possible role for its association with the risk of aggressive prostate cancer. We analysed data from the PRACTICAL consortium consisting of 6207 prostate cancer cases and 6016 controls and a subset of high grade cases (2480 cases). We explored height, polymorphisms in genes related to growth processes as main effects and their possible interactions. The results suggest that height is associated with high-grade prostate cancer risk. Men with height >180 cm are at a 22% increased risk as compared to men with height <173 cm (OR 1.22, 95% CI 1.01-1.48). Genetic variants in the growth pathway gene showed an association with prostate cancer risk. The aggregate scores of the selected variants identified a significantly increased risk of overall prostate cancer and high-grade prostate cancer by 13% and 15%, respectively, in the highest score group as compared to lowest score group. There was no evidence of gene-environment interaction between height and the selected candidate SNPs.Our findings suggest a role of height in high-grade prostate cancer. The effect of genetic variants in the genes related to growth is seen in all cases and high-grade prostate cancer. There is no interaction between these two exposures.

[Low level auditory skills compared to writing skills in school children attending third and fourth grade: evidence for the rapid auditory processing deficit theory?].

PubMed

Ptok, M; Meisen, R

2008-01-01

The rapid auditory processing defi-cit theory holds that impaired reading/writing skills are not caused exclusively by a cognitive deficit specific to representation and processing of speech sounds but arise due to sensory, mainly auditory, deficits. To further explore this theory we compared different measures of auditory low level skills to writing skills in school children. prospective study. School children attending third and fourth grade. just noticeable differences for intensity and frequency (JNDI, JNDF), gap detection (GD) monaural and binaural temporal order judgement (TOJb and TOJm); grade in writing, language and mathematics. correlation analysis. No relevant correlation was found between any auditory low level processing variable and writing skills. These data do not support the rapid auditory processing deficit theory.

Assessing cetacean surveys throughout the Mediterranean Sea: a gap analysis in environmental space.

PubMed

Mannocci, Laura; Roberts, Jason J; Halpin, Patrick N; Authier, Matthieu; Boisseau, Oliver; Bradai, Mohamed Nejmeddine; Cañadas, Ana; Chicote, Carla; David, Léa; Di-Méglio, Nathalie; Fortuna, Caterina M; Frantzis, Alexandros; Gazo, Manel; Genov, Tilen; Hammond, Philip S; Holcer, Draško; Kaschner, Kristin; Kerem, Dani; Lauriano, Giancarlo; Lewis, Tim; Notarbartolo di Sciara, Giuseppe; Panigada, Simone; Raga, Juan Antonio; Scheinin, Aviad; Ridoux, Vincent; Vella, Adriana; Vella, Joseph

2018-02-15

Heterogeneous data collection in the marine environment has led to large gaps in our knowledge of marine species distributions. To fill these gaps, models calibrated on existing data may be used to predict species distributions in unsampled areas, given that available data are sufficiently representative. Our objective was to evaluate the feasibility of mapping cetacean densities across the entire Mediterranean Sea using models calibrated on available survey data and various environmental covariates. We aggregated 302,481 km of line transect survey effort conducted in the Mediterranean Sea within the past 20 years by many organisations. Survey coverage was highly heterogeneous geographically and seasonally: large data gaps were present in the eastern and southern Mediterranean and in non-summer months. We mapped the extent of interpolation versus extrapolation and the proportion of data nearby in environmental space when models calibrated on existing survey data were used for prediction across the entire Mediterranean Sea. Using model predictions to map cetacean densities in the eastern and southern Mediterranean, characterised by warmer, less productive waters, and more intense eddy activity, would lead to potentially unreliable extrapolations. We stress the need for systematic surveys of cetaceans in these environmentally unique Mediterranean waters, particularly in non-summer months.

Interfingering of the Frontier Formation and Aspen Shale, Cumberland Gap, Wyoming.

USGS Publications Warehouse

M'gonigle, J.

1982-01-01

The basal part, or the Chalk Creek Member, of the non-marine lower Frontier Formation (Upper Cretaceous) includes a thin coal bed that grades S into a carbonaceous shale. The latter plus associated sandstones and shales pinch out S of Cumberland Gap and lie stratigraphically below the top of the Aspen Shale. The beds in the upper part of the Aspen, in turn, pinch out within the Frontier Formation. The coal bed and equivalent carbonaceous shale represent in-place accumulation of peat. The interfingering suggests that in SW Wyoming the Lower/Upper Cretaceous boundary is within the Chalk Creek Member. -from Author

Solar cell structure incorporating a novel single crystal silicon material

DOEpatents

Pankove, Jacques I.; Wu, Chung P.

1983-01-01

A novel hydrogen rich single crystal silicon material having a band gap energy greater than 1.1 eV can be fabricated by forming an amorphous region of graded crystallinity in a body of single crystalline silicon and thereafter contacting the region with atomic hydrogen followed by pulsed laser annealing at a sufficient power and for a sufficient duration to recrystallize the region into single crystal silicon without out-gassing the hydrogen. The new material can be used to fabricate semiconductor devices such as single crystal silicon solar cells with surface window regions having a greater band gap energy than that of single crystal silicon without hydrogen.

Results From Scotland's 2016 Report Card on Physical Activity for Children and Youth.

PubMed

Reilly, John J; Johnstone, Avril; McNeill, Geraldine; Hughes, Adrienne R

2016-11-01

The 2016 Active Healthy Kids Scotland Report Card aims to improve surveillance of physical activity (PA), facilitate international comparisons, and encourage evidence-informed PA and health policy. Active Healthy Kids Canada Report Card methodology was used: a search for data on child and adolescent PA and health published after the 2013 Scottish Report Card was carried out. Data sources were considered for grading if based on representative samples with prevalence estimates made using methods with low bias. Ten health behaviors/outcomes were graded on an A to F scale based on quintiles (prevalence meeting recommendations ≥80% graded A down to <20% graded F). Three of the seven Health Behaviors and Outcomes received F or F- grades: Overall PA, Sedentary Behavior, and Obesity. Active and Outdoor Play and Organized Sport Participation could not be graded. Active Commuting to School was graded C, and Diet was graded D-. Family and Peer Influence was graded D-; Perceived Safety and Availability of Space for PA as well as the National Policy Environment were more favorable (both B). Grades were identical to those in 2013. Scotland has a generally favorable environment for PA, but children and adolescents have low PA and high sedentary behavior. Gaps in surveillance included lack of objectively measured PA, no surveillance of moderate-to-vigorous PA in children, summary surveillance data not expressed in ways which match recommendations (eg, for PA in young children; for screen-time), and no surveillance of Sport Participation, Active and Outdoor Play, or Sitting. Scottish policy does not include sedentary behavior at present.

Influence of pore structure on carbon retention/loss in soil macro-aggregates

NASA Astrophysics Data System (ADS)

Quigley, Michelle; Kravchenko, Alexandra; Rivers, Mark

2017-04-01

Carbon protection within soil macro-aggregates is an important component of soil carbon sequestration. Pores, as the transportation network for microorganisms, water, air and nutrients within macro-aggregates, are among the factors controlling carbon protection through restricting physical accessibility of carbon to microorganisms. The understanding of how the intra-aggregate pore structure relates to the degree of carbon physical protection, however, is currently lacking. This knowledge gap can lead to potentially inaccurate models and predictions of soil carbon's fate and storage in future changing climates. This study utilized the natural isotopic difference between C3 and C4 plants to trace the location of newly added carbon within macro-aggregates before and after decomposition and explored how location of this carbon relates to characteristics of intra-aggregate pores. To mimic the effect of decomposition, aggregates were incubated at 23˚ C for 28 days. Computed micro-tomographic images were used to determine pore characteristics at 6 μm resolution before and after incubation. Soil (0-10 cm depth) from a 20 year continuous corn (C4 plant) experiment was used. Two soil treatments were considered: 1) "destroyed-structure", where 1 mm sieved soil was used and 2) "intact-structure", where intact blocks of soil were used. Cereal rye (Secale cereale L.) (C3 plant) was grown in the planting boxes (2 intact, 3 destroyed, and one control) for three months in a greenhouse. From each box, ˜5 macro-aggregates of ˜5 mm size were collected for a total of 27 macro-aggregates. Half of the aggregates were cut into 5-11 sections, with relative positions of the sections within the aggregate recorded, and analyzed for δ13C. The remaining aggregates were incubated and then subjected to cutting and δ13C analysis. While there were no significant differences between the aggregate pore size distributions of the two treatments, the roles that specific pores sizes played in carbon protect were disparate. In intact-structure aggregates, prior to incubation, there was no association between carbon distribution and pores. After incubation, significant correlations (α=0.05) were observed between abundance of 6-40 μm pores and both soil organic carbon (SOC) and δ13C. Sections containing more 6-40 μm pores also had increased amounts of SOC (r2=0.23) with higher presence of C4 carbon (r2=0.27). This indicates preferential preservation of older carbon in the pores of this size range. Prior to incubation, destroyed-structure aggregates had higher amounts of C3 carbon associated with 40-95 μm pores (r2=0.14), pointing to a greater presence of newly added carbon within these pores. However, after incubation there was a significant loss of SOC from these pores (r2=0.22) and, specifically, the loss of C3 carbon (r2=0.16). In the studied soil, pores of 6-40 μm size range appeared to control the preservation of older carbon, while 40-95 μm pores controlled the fate of newly added carbon. Older carbon preservation in 6-40 μm pores was mostly observed in macro-aggregates from the soil with intact structure, while the associations between 40-95 μm pores and gains and losses of newly added carbon were primarily observed in the macro-aggregates that were formed anew in the sieved soil during the plant growing experiment.

Dust coagulation and magnetic field strength in a planet-induced gap subject to MRI turbulence

NASA Astrophysics Data System (ADS)

Carballido, Augusto; Matthews, Lorin; Hyde, Truell

2017-01-01

We investigate the coagulation of dust particles in and around a gap opened by a Jupiter-mass planet. To this end, we carry out a high-resolution magnetohydrodynamic (MHD) simulation of the gap environment, which is turbulent due to the magneto rotational instability. From the MHD simulation, we obtain values of the gas velocities, densities and turbulent stresses close to the gap edge, in one of the two gas streams that accrete onto the planet, and inside the low-density gap. The MHD values are then supplied to a Monte Carlo dust coagulation algorithm, which models grain sticking, compaction and bouncing. We consider two dust populations for each region: one whose initial size distribution is monodisperse, with monomer radius equal to 1 micron, and another one whose initial size distribution follows the Mathis-Rumpl-Nordsieck distribution for interstellar dust grains, with an initial range of monomer radii between 0.5 and 10 microns. Without bouncing, our Monte Carlo calculations show steady growth of dust aggregates in all regions, and the mass-weighted (MW) average porosity of the initially mono disperse population reaches extremely high final values of 98%. The final MW porosities in all other cases without bouncing range from 30% to 82%. The efficiency of compaction is due to high turbulent relative speeds between dust particles. When bouncing is introduced, growth is slowed down in the planetary wake and inside the gap.We also analyze the strength of the magnetic field threading the gaps opened by planets of different sub-Jovian masses. Preliminary results show that, in a gap opened by a large-mass planet (~ 1 MJ), the time-averaged radial profile of the vertical component of the field (Bz) increases sharply inside the gap, and less sharply in the case of less massive planets. In gaps opened by intermediate-mass planets (~ 0.5 — 0.75 MJ), the radial profile of Bz exhibits local maxima in the vicinity of the planet, but not at the gap center.

Inclusion of aggregation effect to evaluate the performance of organic dyes in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Sun, Kenan; Zhang, Weiyi; Heng, Panpan; Wang, Li; Zhang, Jinglai

2018-05-01

Two new indoline-based D-A-π-A dyes, D3F and D3F2 (see Scheme 1), are developed on the basis of the reported D3 by insertion of one or two F atoms on benzothiadiazole group. Our central aim is to explore high-efficiency organic dyes applied in dye-sensitized solar cells by inclusion of a simple group rather than by employment of new complicated groups. The performance of two new designed organic dyes, D3F and D3F2, is compared with that of D3 from various aspects including absorption spectrum, light harvesting efficiency, driving force, and open-circuit voltage. Besides the isolated dye, the interfacial property between dye and TiO2 surface is studied. D3F and D3F2 do not show absolute superiority than D3 not only for the isolated dyes but also for the monomeric adsorption system. However, D3F and D3F2 would effectively reduce the influence of aggregation resulting in the much smaller intermolecular electronic coupling. Although the aggregation has attracted much attention recently, it is studied alone in most of studies. To comprehensively evaluate the performance of dye-sensitized solar cells, it is necessary to consider aggregation along with electron injection time from dye into TiO2 rather than only static items, such as, band gap and absorption region.

Stormwater Pollution Prevention Plan (SWPPP) for Coal Storage Area Stabilization Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Project and Design Engineering

2011-03-01

The scope of this project is to stabilize the abandoned coal storage area and redirect the storm water runoff from sanitary sewer system to the storm drain system. Currently, the existing storm water runoff is directed to a perimeter concrete drainage swale and collected in a containment basin. The collected water is then pumped to a treatment facility and after treatment, is discharged to the Y-12 sanitary sewer system. The existing drainage swale and collection basin along with silt fencing will be used during aggregate placement and grading to provide erosion and sediment control. Inlet protection will also be installedmore » around existing structures during the storm water diversion construction. This project scope will include the installation of a non-woven geotextile fabric and compacted mineral aggregate base (paving optional) to stabilize the site. The geotextile specifications are provided on the vendor cut sheets in Appendix B. The installation of a storm water collection/retention area will also be installed on the southern side of the site in accordance with EPA Technical Guidance on Implementing the Stormwater Runoff Requirements for federal Projects under Section 438 of the Energy Independence and Security Act. The total area to be disturbed is approximately 2.5 acres. The order of activities for this Stormwater Pollution Prevention Plan (SWPPP) will be: (1) post notice of coverage (NOC) in a prominent display near entrance of the site; (2) install rain gauge on site or contact Y-12 Plant Shift Superintendent daily for Met tower rain gauge readings; (3) install stabilized construction exit on site; (4) install silt fencing along perimeter as indicated on the attached site plan; (5) regrade site; (6) install geotextile fabric and compacted mineral aggregate base; (7) install catch basin inlet protection where required; (8) excavate and lower existing catch basin tops, re-grade and asphalt to drain; and (9) when all disturbed areas are re-stabilized, remove silt fencing and any other temporary erosion control.« less

Previous concrete as one of the technology to overcome the puddle

NASA Astrophysics Data System (ADS)

Agung Putra Handana, M.; Karolina, Rahmi; Syahputra, Eko; Zulfikar

2018-03-01

Some construction waste has been utilized as a material in certain concrete compositions for engineering building materials. One is a concrete that has been removed after testing at a laboratory called recycle concrete. Disposed concrete, crushed and filtered with filter number 50; 37.5; 19; 9.5; and 4.75 mm are subsequently converted into rough aggregate materials in the manufacture of pervious concrete to be tested for compressive strength and infiltration velocity to water. Pervious concrete test specimens in the form of cylinders with dimensions (15 x 30) cm and plate-shaped with dimension (100 x 100 x 10) cm with the quality plan Fc ' = 15 MPa at age 28 days. The research methodology consisted of testing of wear, test object preparation, periodic maintenance, visual inspection, compressive strength testing, and infiltration rate of specimens against water (based on ASTM C1701). Treatment of specimens by spraying periodically before the test time. From the results of the Los Angeles wear test, it appears that recycled aggregate has an average wear rate of 20.88% (based on SNI 03-2417-1991) on the Los Angeles test) and the visual test on the specimen is appropriate (based on SNI 03 -0691-1996 on paving block) as the basis for testing the specimens. The largest compressive strength was found in pervious concrete with 9.5 mm graded aggregates of 5.89 MPa, while the smallest compressive strength of 50 mm gradation was 2.15 MPa and had a compressive strength of 28% of pervious concrete compressive strength on generally (based on SNI 03-6805-2002). The fastest infiltration speed occurs in 50 mm pervious gradient concrete at 4.52 inc / hr and is late in 9.5 mm grading of 2.068 inc / hr or an inflation rate inflation rate of 54.25% for gradation of 9.5 mm to 50 mm gradation, So that in accordance with the purpose of pervious concrete use, concrete that can drain water to the bottom layer

1 Tb/s x km multimode fiber link combining WDM transmission and low-linewidth lasers.

PubMed

Gasulla, I; Capmany, J

2008-05-26

We have successfully demonstrated an error-free transmission of 10 x 20 Gb/s 200 GHz-spaced ITU channels through a 5 km link of 62.5-microm core-diameter graded-index multimode silica fiber. The overall figure corresponds to an aggregate bit rate per length product of 1 Tb/s x km, the highest value ever reported to our knowledge. Successful transmission is achieved by a combination of low-linewidth DFB lasers and the central launch technique.

Stereotyped: investigating gender in introductory science courses.

PubMed

Lauer, Shanda; Momsen, Jennifer; Offerdahl, Erika; Kryjevskaia, Mila; Christensen, Warren; Montplaisir, Lisa

2013-01-01

Research in science education has documented achievement gaps between men and women in math and physics that may reflect, in part, a response to perceived stereotype threat. Research efforts to reduce achievement gaps by mediating the impact of stereotype threat have found success with a short values-affirmation writing exercise. In biology and biochemistry, however, little attention has been paid to the performance of women in comparison with men or perceptions of stereotype threat, despite documentation of leaky pipelines into professional and academic careers. We used methodologies developed in physics education research and cognitive psychology to 1) investigate and compare the performance of women and men across three introductory science sequences (biology, biochemistry, physics), 2) document endorsement of stereotype threat in these science courses, and 3) investigate the utility of a values-affirmation writing task in reducing achievement gaps. In our study, analysis of final grades and normalized learning gains on content-specific concept inventories reveals no achievement gap in the courses sampled, little stereotype threat endorsement, and no impact of the values-affirmation writing task on student performance. These results underscore the context-dependent nature of achievement gaps and stereotype threat and highlight calls to replicate education research across a range of student populations.

Stereotyped: Investigating Gender in Introductory Science Courses

PubMed Central

Lauer, Shanda; Momsen, Jennifer; Offerdahl, Erika; Kryjevskaia, Mila; Christensen, Warren; Montplaisir, Lisa

2013-01-01

Research in science education has documented achievement gaps between men and women in math and physics that may reflect, in part, a response to perceived stereotype threat. Research efforts to reduce achievement gaps by mediating the impact of stereotype threat have found success with a short values-affirmation writing exercise. In biology and biochemistry, however, little attention has been paid to the performance of women in comparison with men or perceptions of stereotype threat, despite documentation of leaky pipelines into professional and academic careers. We used methodologies developed in physics education research and cognitive psychology to 1) investigate and compare the performance of women and men across three introductory science sequences (biology, biochemistry, physics), 2) document endorsement of stereotype threat in these science courses, and 3) investigate the utility of a values-affirmation writing task in reducing achievement gaps. In our study, analysis of final grades and normalized learning gains on content-specific concept inventories reveals no achievement gap in the courses sampled, little stereotype threat endorsement, and no impact of the values-affirmation writing task on student performance. These results underscore the context-dependent nature of achievement gaps and stereotype threat and highlight calls to replicate education research across a range of student populations. PMID:23463226

StarD13 is a tumor suppressor in breast cancer that regulates cell motility and invasion

PubMed Central

HANNA, SAMER; KHALIL, BASSEM; NASRALLAH, ANITA; SAYKALI, BECHARA A.; SOBH, RANIA; NASSER, SELIM; EL-SIBAI, MIRVAT

2014-01-01

Breast cancer is one of the most commonly diagnosed cancers in women around the world. In general, the more aggressive the tumor, the more rapidly it grows and the more likely it metastasizes. Members of the Rho subfamily of small GTP-binding proteins (GTPases) play a central role in breast cancer cell motility and metastasis. The switch between active GTP-bound and inactive GDP-bound state is regulated by guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs) and guanine-nucleotide dissociation inhibitors (GDIs). We studied the role of StarD13, a recently identified Rho-GAP that specifically inhibits the function of RhoA and Cdc42. We aimed to investigate its role in breast cancer proliferation and metastasis. The levels of expression of this Rho-GAP in tumor tissues of different grades were assayed using immunohistochemistry. We observed that, while the level of StarD13 expression decreases in cancer tissues compared to normal tissues, it increases as the grade of the tumor increased. This was consistent with the fact that although StarD13 was indeed a tumor suppressor in our breast cancer cells, as seen by its effect on cell proliferation, it was needed for cancer cell motility. In fact, StarD13 knockdown resulted in an inhibition of cell motility and cells were not able to detach their tail and move forward. Our study describes, for the first time, a tumor suppressor that plays a positive role in cancer motility. PMID:24627003

Combined research effort on aggregate road materials

NASA Astrophysics Data System (ADS)

Kuznetsova, Elena; Hoff, Inge; Willy Danielsen, Svein; Wigum, Børge Johannes; Fladvad, Marit; Rieksts, Karlis; Loranger, Benoit; Barbieri, Diego

2017-04-01

In European countries, the average aggregate consumption per capita is 5 tons per year (European Aggregates Association 2016), while the corresponding number in Norway is 11 tons (Neeb 2015). Due to the increased demand for sand and gravel for construction purposes, e.g. in road construction, the last decade has seen a significant trend towards the use of crushed rock aggregates. Neeb (2015) reports that half of the Norwegian aggregate production (sand, gravel and crushed rock) is used for road construction, and 33 % of the overall sold tonnage of crushed rock is exported. This resource has been more and more preferred over sand and gravel due to the significant technological development of its process and utilization phase. In Norway, the development and implementation of crushed aggregate technology has been the main approach to solve natural resource scarcity (Danielsen and Kuznetsova 2015). In order to reduce aggregates transportation, it is aimed to use local aggregates and aggregates processed from rock excavations, tunneling, road cuts, etc. One issue focused in this research is the influence from blasting and processing on the final quality of the crushed aggregates, specifically relating to the properties for road construction purposes. It is therefor crucial to plan utilization of available materials for use in different road layers following the same production line. New developments and improved availability of mobile crushing and screening equipment could produce more sustainable and profitable sources of good quality aggregate materials from small volume deposits in proximity to construction sites. One of the biggest challenges today to use these materials is that the pavement design manual sets rigid requirements for pavement layers. Four research projects are being conducted in Norway to improve the use of local materials for road construction. Four aspects are to be covered by the research: a) geological characteristics of the materials, their b) mechanical and c) thermal properties, and d) frost action and susceptibility. The main goal of the PhD topic N1 is to achieve better utilization of aggregate resources through adjusting the production process according to local geological conditions and construction needs. The objective of the PhD project N2 is to look at the design stage and find the way to use these aggregates anyway by changing the road's design (e.g. increasing the thickness of asphalt layer). Fine particles content will also be harder to control due to rock type variability from site to site. Thus, PhD project N3 is going to investigate the effect of the increasing of fines and their mineralogy on frost action related problems during freezing and thawing seasons. Finally, PhD project N4 is investigating how the grading and mineralogy of the crushed rock material affects the heat exchange in road's granular layers and consequently, the frost penetration depth. Combining these PhD studies we aim to create a holistic approach for a new understanding within this very complex area.

Early Care and Education in the Golden State: Publicly Funded Programs Serving California's Preschool-Age Children

ERIC Educational Resources Information Center

Karoly, Lynn A.; Reardon, Elaine; Cho, Michelle

2007-01-01

To evaluate the adequacy and efficiency of preschool education, the RAND Corporation has undertaken the California Preschool Study to improve understanding of achievement gaps in the early elementary grades, the adequacy of preschool education currently given, and what efficiencies or additional resources might be brought to bear in early care and…

Kindergarten through 12th Grade Project in Career Development and Bridging the Gap Between School and Work: Final Report.

ERIC Educational Resources Information Center

Watertown Independent School District 1, SD.

Divided into four phases, this project in career education includes the following aspects: planning of project policies and activities and securing resource materials; orientation of the school district staff to the project; integration of occupational information, exploration, and career education concepts into the curriculum, identification of…

Using Curriculum-Based Measurement to Examine Summer Learning Loss

ERIC Educational Resources Information Center

Sandberg Patton, Karen L.; Reschly, Amy L.

2013-01-01

Summer loss of reading is a potential factor in maintaining, and potentially widening, the achievement gap. This study used curriculum-based measurement of reading (R-CBM) to investigate the effect of the summer on reading. For this study, 317 students in Grades 2 to 5 were assessed in the spring and fall using Dynamic Indicators of Basic Early…

Utilizing Two-Way Bilingual Education for Reducing the Achievement Lag of LEP Students in Primary Grades: A Longitudinal Study.

ERIC Educational Resources Information Center

Lopez, Maria G.; Tashakkori, Abbas

This study investigated the effect of a bilingual education program on the achievement gap in language development between at-risk kindergarten students with minimal English proficiency and students who were proficient English speakers. Limited English Proficient (LEP) students were included in an Extended Foreign Language (EFL) program designed…

Equity in Standards-Based Elementary Mathematics Classrooms. Weaving Gender Equity into Math Reform.

ERIC Educational Resources Information Center

Perez, Christina

This article discusses the issue of equity in standards-based elementary mathematics classrooms. It is argued that while some of the gaps in mathematics achievement have slowly diminished (e.g., differences in mathematics grades and participation rates between girls and boys in K-12 education have decreased), others remain intractable. Other…

Using Peer Assisted Learning Strategies for Boys, Aboriginal Learners, and At-Risk Populations

ERIC Educational Resources Information Center

Mattatall, Chris A.

2017-01-01

This study reports on one school district's attempt to address reading gaps in boys, Aboriginal students, and special education students at 1st grade by implementing Peer Assisted Learning Strategies (PALS) to supplement classroom reading instruction. Findings indicate that compared to previous years, when PALS was not used, students in this study…

Implications of Literacy Related to Comprehension of Environmental Health Materials

ERIC Educational Resources Information Center

Lindsey, Martha Ann

2010-01-01

Health literacy involves basic reading and numeracy, which allow a person to function as a health care consumer, by reading, understanding, evaluating and using information in health documents. For thirty years, the gap between the reading level of most of the public, eighth grade, and the reading level of most written health information, above…

Sexual Dating Aggression across Grades 8 through 12: Timing and Predictors of Onset

ERIC Educational Resources Information Center

Reyes, H. Luz McNaughton; Foshee, Vangie A.

2013-01-01

Investigators have identified a number of factors that increase risk for physical and psychological dating abuse perpetration during adolescence, but as yet little is known about the etiology of sexual dating aggression during this critical developmental period. This is an important gap in the literature given that research suggests that patterns…

Black and Hispanic Immigrants' Resilience against Negative-Ability Racial Stereotypes at Selective Colleges and Universities in the United States

ERIC Educational Resources Information Center

Owens, Jayanti; Lynch, Scott M.

2012-01-01

Stereotype threat is a widely supported theory for understanding the racial achievement gap in college grade performance. However, today's minority college students are increasingly of immigrant origins, and it is unclear whether two dispositional mechanisms that may increase susceptibility to stereotype threat are applicable to immigrants. We use…

Mathematics and Science Test Gaps. Pell Institute Fact Sheet. Updated

ERIC Educational Resources Information Center

Pell Institute for the Study of Opportunity in Higher Education, 2011

2011-01-01

Data is reported as percentages in 4th, 8th, and 12th grades based on proficiency in the subject ("Below Basic," "At Basic," "At Proficient", or "At Advanced"). "Low-income" on this data sheet means students who qualify for the National School Lunch Program. Both math and science data are from 2009…

Unconscious Bias in the Classroom: Evidence and Opportunities, 2017

ERIC Educational Resources Information Center

Dee, T.; Gershenson, S.

2017-01-01

The underrepresentation of women and racial and ethnic minorities in computer science (CS) and other fields of science, technology, engineering, and math (STEM) is a serious impediment to technological innovation as well as an affront to fundamental notions of fairness and equity. These gaps emerge in the early grades and tend to persist, if not…

The Impact of L2 German on Component Processes of Reading

ERIC Educational Resources Information Center

Schröter, Pauline; Schroeder, Sascha

2017-01-01

Background: In Germany, there is a substantial gap in reading literacy between monolingual children and their L2-speaking peers. Nevertheless, it is still unclear where these performance differences are rooted. Methods: We investigated children of grades 5, 6 and 7 with comparable socio-economic status, who completed a battery of tests assessing…

Reducing Achievement Gaps in Academic Writing for Latinos and English Learners in Grades 7-12

ERIC Educational Resources Information Center

Olson, Carol Booth; Matuchniak, Tina; Chung, Huy Q.; Stumpf, Rachel; Farkas, George

2017-01-01

This study reports 2 years of findings from a randomized controlled trial designed to replicate and demonstrate the efficacy of an existing, successful professional development program, the Pathway Project, that uses a cognitive strategies approach to text-based analytical writing. Building on an earlier randomized field trial in a large, urban,…

Enhancing the Vocabulary Knowledge of First-Grade Children with Supplemental Booster Instruction

ERIC Educational Resources Information Center

Puhalla, Eve M.

2011-01-01

This study examined the effects of instructional intensity on the acquisition of storybook vocabulary in first graders who were at risk of early reading failure. It also measured whether the intervention was effective for closing the vocabulary knowledge gap between students who were at risk and their average-achieving peers. A total of 66…

The Effect of Elementary Mathematics Coaching on Student Achievement in Fourth, Fifth, and Sixth Grade

ERIC Educational Resources Information Center

Trimuel Stewart, Merita

2013-01-01

Due to recent waivers and current expectations of teacher performance, schools have been tasked to close their student achievement gaps in mathematics by 2014. Yet students still have not performed well in mathematics, which may be a direct link to teachers' instructional practices. Identifying a coaching model to improve student achievement…

Learning from Rising Sixth Grade Readers: How Nooks Shaped Students' Reading Behaviors during a Summer Independent Reading Initiative

ERIC Educational Resources Information Center

Mitchell, Chrystine Cooper

2016-01-01

Researchers have documented a "summer reading setback" where an achievement gap between proficient and struggling readers expands during the summer. This research focuses on 20 rising sixth graders who participated in a summer independent reading initiative using Nook digital readers. Using a qualitative exploratory design and content…

Reflections from the Computer Equity Training Project.

ERIC Educational Resources Information Center

Sanders, Jo Shuchat

This paper addresses girls' patterns of computer avoidance at the middle school and other grade levels. It reviews the evidence for a gender gap in computer use in several areas: in school, at home, in computer camps, in computer magazines, and in computer-related jobs. It compares the computer equity issue to math avoidance, and cites the middle…

Brief Report: Activities in Heterosexual Romantic Relationships--Grade Differences and Associations with Relationship Satisfaction

ERIC Educational Resources Information Center

Carlson, Wendy; Rose, Amanda J.

2012-01-01

Whereas much research addresses relations of youths' heterosexual romantic relationships with sexual and/or delinquent activities, less attention has been paid to youths' more normative, day-to-day activities with romantic partners. This gap in the literature is problematic given that these activities define the substance of the relationships and…

Developing Deep Understanding and Literacy while Addressing a Gender-Based Literacy Gap

ERIC Educational Resources Information Center

Sun, Yanqing; Zhang, Jianwei; Scardamalia, Marlene

2010-01-01

Online discourse from a class of 22 students (11 boys and 11 girls) was analysed to assess advances in conceptual understanding and literacy. The students worked over a two-year period (Grades 3-4), during which they contributed notes to an online Knowledge Building environment--Knowledge Forum[R]. Contributions revealed that both boys and girls…

A Qualitative Analysis of Ninth Grade High School Teachers' Perceptions of Online Discussions to Supplement Classroom Instruction

ERIC Educational Resources Information Center

Watson, Rhonda

2015-01-01

Current web technologies are changing the landscape of education. Today's students communicate and learn differently than those of previous generations, yet a gap still exists between available technology and teacher use of technology for instruction. The purpose of this qualitative descriptive case study was to examine teachers' perceptions of…

Understanding the Gap in Mathematics Achievement of Malaysian Students

ERIC Educational Resources Information Center

Ismail, Noor Azina

2009-01-01

Of 46 countries that participated in the Trends in International Mathematics and Science Study in 2003 (I. V. S. Mullis, M. O. Martin, E. J. Gonzalez, & S. J. Chrostowski, 2004), Malaysia was ranked 10th in international scores of mathematics achievement for 8th-grade students. The present author aimed to examine the importance of students'…

Depression and Suicidality among Bisexual Youth: A Nationally Representative Sample

ERIC Educational Resources Information Center

Taliaferro, Lindsay A.; Gloppen, Kari M.; Muehlenkamp, Jennifer J.; Eisenberg, Marla E.

2018-01-01

To address gaps in the literature on bisexual youth, we used the first nationally representative sample of high school students from the United States to determine profiles of behaviors related to depressive symptoms, a suicide attempt, and a medically-serious attempt. We examined the data from 922 bisexual students in grades 9-12 who completed…

How the Word Gap Argument Negatively Impacts Young Children of Latinx Immigrants' Conceptualizations of Learning

ERIC Educational Resources Information Center

Adair, Jennifer Keys; Colegrove, Kiyomi Sánchez-Suzuki; McManus, Molly E.

2017-01-01

Early childhood education in grades preK-3 continues to contribute to future school success. Discrimination, however, can still be an obstacle for many children of Latinx immigrants because they often receive less sophisticated and dynamic learning experiences than their white, native-born peers. In this article, Jennifer Keys Adair, Kiyomi…

Testing for Results: Helping Families, Schools and Communities Understand and Improve Student Achievement.

ERIC Educational Resources Information Center

Department of Education, Washington, DC. Office of the Under Secretary.

Redefining the federal government's role in kindergarten through grade 12 education, the No Child Left Behind Act of 2001 is designed to close the achievement gap between disadvantaged and minority students and their peers. The act is based on four principles, the first of which is stronger accountability for results, entailing creation of…

Modelling of Factors Influencing Gender Difference in Mathematics Achievement Using TIMSS 2011 Data for Singaporean Eighth Grade Students

ERIC Educational Resources Information Center

Yoo, Yang Seok

2018-01-01

Numerous studies have attributed gender difference in mathematics achievement to various sociocultural influences. Singapore is a country of higher gender equality as represented in the Global Gender Gap Index and Singaporean girls perform as well or higher than boys in international mathematics assessments. This study develops a conceptual model…

The Use of a Reading Intervention Program with Students at Risk of Reading Failure

ERIC Educational Resources Information Center

Browning, Angela Dixon

2010-01-01

A gap remains in the literature addressing reading intervention programs that have been successful for students identified as at risk of reading failure in grades kindergarten through second. The purpose of this qualitative case study was to explore how the Scott Foresman Early Reading Intervention Program supported the improvement of literacy…

Evidence-Based Practices: Applications of Concrete Representational Abstract Framework across Math Concepts for Students with Mathematics Disabilities

ERIC Educational Resources Information Center

Agrawal, Jugnu; Morin, Lisa L.

2016-01-01

Students with mathematics disabilities (MD) experience difficulties with both conceptual and procedural knowledge of different math concepts across grade levels. Research shows that concrete representational abstract framework of instruction helps to bridge this gap for students with MD. In this article, we provide an overview of this strategy…