Narrowing the Gap in Outcomes for Vulnerable Groups: Overview and Analysis of Available Datasets on Vulnerable Groups and the Five ECM Outcomes. Executive Summary

ERIC Educational Resources Information Center

Morris, Marian

2007-01-01

This summary presents the main findings from a data mapping and analysis study commissioned by the Local Government Association (LGA) from the National Foundation for Educational Research (NFER) as part of a two-year development and research programme, Narrowing the Gap. This programme seeks to make a significant difference in "narrowing the…

For blacks in America, the gap in neighborhood poverty has declined faster than segregation

PubMed Central

Acciai, Francesco

2016-01-01

Black residential segregation has been declining in the United States. That accomplishment rings hollow, however, if blacks continue to live in much poorer neighborhoods than other Americans. This study uses census data for all US metropolitan areas in 1980 and 2010 to compare decline in the neighborhood poverty gap between blacks and other Americans with decline in the residential segregation of blacks. We find that both declines resulted primarily from narrowing differences between blacks and whites as opposed to narrowing differences between blacks and Hispanics or blacks and Asians. Because black–white differences in neighborhood poverty declined much faster than black–white segregation, the neighborhood poverty disadvantage of blacks declined faster than black segregation—a noteworthy finding because the narrowing of the racial gap in neighborhood poverty for blacks has gone largely unnoticed. Further analysis reveals that the narrowing of the gap was produced by change in both the medians and shapes of the distribution of poverty across the neighborhoods where blacks, whites, Hispanics, and Asians reside. PMID:27821759

For blacks in America, the gap in neighborhood poverty has declined faster than segregation.

PubMed

Firebaugh, Glenn; Acciai, Francesco

2016-11-22

Black residential segregation has been declining in the United States. That accomplishment rings hollow, however, if blacks continue to live in much poorer neighborhoods than other Americans. This study uses census data for all US metropolitan areas in 1980 and 2010 to compare decline in the neighborhood poverty gap between blacks and other Americans with decline in the residential segregation of blacks. We find that both declines resulted primarily from narrowing differences between blacks and whites as opposed to narrowing differences between blacks and Hispanics or blacks and Asians. Because black-white differences in neighborhood poverty declined much faster than black-white segregation, the neighborhood poverty disadvantage of blacks declined faster than black segregation-a noteworthy finding because the narrowing of the racial gap in neighborhood poverty for blacks has gone largely unnoticed. Further analysis reveals that the narrowing of the gap was produced by change in both the medians and shapes of the distribution of poverty across the neighborhoods where blacks, whites, Hispanics, and Asians reside.

NAFTA and the Mexican Economy

DTIC Science & Technology

2008-11-04

Paper, GDP Growth, Potential Output, and Output Gaps in Mexico, by Ebrima Faal, May 2005. 12 EIU, Country Reports: Mexico, various years. 13 EIU...positive overall effect on the Mexican economy, narrowing the U.S.-Mexico gap in prices of goods and services and the differential in real wages...improve economic conditions in Mexico and narrow the income gap between Mexico and the United States. Studies that have addressed the issue of

NARROW-GAP POINT-TO-PLANE CORONA WITH HIGH VELOCITY FLOWS

EPA Science Inventory

The article discusses a mathematical model developed to describe a narrow- gap point- to- plane corona system used in the detoxification of chemical agents or their simulants, for which the degree of destruction depends on the strength of the electric field or electron energy. Na...

High-Pressure Study of Perovskite-Like Organometal Halide: Band-Gap Narrowing and Structural Evolution of [NH 3 -(CH 2 ) 4 -NH 3 ]CuCl 4

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

Li, Qian; Li, Shourui; Wang, Kai

Searching for nontoxic and stable perovskite-like alternatives to lead-based halide perovskites for photovoltaic application is one urgent issue in photoelectricity science. Such exploration inevitably requires an effective method to accurately control both the crystalline and electronic structures. This work applies high pressure to narrow the band gap of perovskite-like organometal halide, [NH 3-(CH 2) 4-NH 3]CuCl 4 (DABCuCl4), through the crystalline-structure tuning. The band gap keeps decreasing below ~12 GPa, involving the shrinkage and distortion of CuCl 4 2–. Inorganic distortion determines both band-gap narrowing and phase transition between 6.4 and 10.5 GPa, and organic chains function as the springmore » cushion, evidenced by the structural transition at ~0.8 GPa. The supporting function of organic chains protects DABCuCl 4 from phase transition and amorphization, which also contributes to the sustaining band-gap narrowing. This work combines crystal structure and macroscopic property together and offers new strategies for the further design and synthesis of hybrid perovskite-like alternatives.« less

The Structure of A Pacific Narrow Cold Frontal Rainband

NASA Technical Reports Server (NTRS)

Jorgensen, David P.; Pu, Zhaoxia; Persson, Ola; Tao, Wei-Kuo; Starr, David OC. (Technical Monitor)

2002-01-01

A NOAA P-3 instrumented aircraft observed an intense, fast-moving narrow cold frontal Farmhand as it approached the Pacific Northwest coast on 19 February 2001 during the Pacific Coastal Jets Experiment. Pseudo-dual-Doppler analyses performed on the airborne Doppler radar data while the frontal system was well offshore indicated that a narrow ribbon of very high radar reflectively convective cores characterized the Farmhand at low levels with echo tops to approximately 4-5 km. The NCFR exhibited gaps in its narrow ribbon of high reflectively, probably as a result of hydrodynamic instability all no its advancing cold pool leading edge. In contrast to some earlier studies of cold frontal rainbands, density current theory described well the motion of the overall front. The character of the updraft structure associated with the heavy rainfall at its leading edge varied across the gap region. The vertical shear of the cross-frontal low-level ambient flow exerted a strong influence on the updraft character, consistent with theoretical arguments developed for squall lines describing the balance of vorticity at the leading edge. In short regions south of the gaps the vertical wind shear was strongest with the updrafts and rain shafts more intense, narrower, and more erect or even downshear tilted. North of the gaps the wind shear weakened with less intense Dihedrals which tilted upshear with a broader band of rainfall. Simulations using a nonhydrostatic mesoscale nested grid model are used to investigate the gap regions, particularly the balance of cold pool induced to pre-frontal ambient shears at the leading edge. Observations confirm the model results that the updraft character depends on the balance of vorticity at the leading edge. Downshear-tilted updrafts imply that convection south of the gap regions would weaken with time relative to the frontal segments north of the gaps since inflow air would be affected by passage through the heavy rain region before ascent, suggesting a mechanism for gap filling.

Strategies for narrowing the maize yield gap of household farms through precision fertigation under irrigated conditions using CERES-Maize model.

PubMed

Liu, Jiangang; Wang, Guangyao; Chu, Qingquan; Chen, Fu

2017-07-01

Nitrogen (N) application significantly increases maize yield; however, the unreasonable use of N fertilizer is common in China. The analysis of crop yield gaps can reveal the limiting factors for yield improvement, but there is a lack of practical strategies for narrowing yield gaps of household farms. The objectives of this study were to assess the yield gap of summer maize using an integrative method and to develop strategies for narrowing the maize yield gap through precise N fertilization. The results indicated that there was a significant difference in maize yield among fields, with a low level of variation. Additionally, significant differences in N application rate were observed among fields, with high variability. Based on long-term simulation results, the optimal N application rate was 193 kg ha -1 , with a corresponding maximum attainable yield (AY max ) of 10 318 kg ha -1 . A considerable difference between farmers' yields and AY max was observed. Low agronomic efficiency of applied N fertilizer (AE N ) in farmers' fields was exhibited. The integrative method lays a foundation for exploring the specific factors constraining crop yield gaps at the field scale and for developing strategies for rapid site-specific N management. Optimization strategies to narrow the maize yield gap include increasing N application rates and adjusting the N application schedule. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Aiming at Narrowing Social Gaps in Israel through a Special Program of Everyman's University.

ERIC Educational Resources Information Center

Guri, Sarah

The philosophy and implementation of the Community Leaders Project at Everyman's University (EU), the Open University of Israel, are discussed. The project is designed to narrow social gaps in Israel by upgrading the educational level of disadvantaged populations and by developing indigeneous leadership for decision-making in the most…

Boiling Visualization and Critical Heat Flux Phenomena In Narrow Rectangular Gap

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

J. J. Kim; Y. H. Kim; S. J. Kim

2004-12-01

An experimental study was performed to investifate the pool boling critical hear flux (CHF) on one-dimensional inclined rectangular channels with narrow gaps by changing the orientation of a copper test heater assembly. In a pool of saturated water at atmospheric pressure, the test parameters include the gap sizes of 1,2,5, and 10 mm, andthe surface orientation angles from the downward facing position (180 degrees) to the vertical position (90 degress) respectively.

Data correlation and analysis of arc tunnel and wind tunnel tests of RSI joints and gaps, phase 2. Volume 1: Technical report

NASA Technical Reports Server (NTRS)

Cristensen, H. E.

1975-01-01

Heat transfer data measured in gaps representative of those being employed for joints in the space shuttle reusable surface insulation (RSI) thermal protection systems (TPS) were assimilated, analyzed, and correlated. Several types of gap were investigated with emphasis on simple butt joints. Gap widths ranged from 0.0 to 0.76 cm and depths ranged from 1 to 6 cm. Laminar, transitional, and turbulent boundary layer flows over the gap opening were investigated. The angle between gap axis and external flow was varied between 0 and pi/2 radians. The contoured cross section gap performed significantly better than all other wide gaps and slightly better than all other narrow gap geometries. Three dimensional heating variations were observed within gaps in the absence of external flow pressure gradients. Interactions between heating within gaps and heating of adjacent top tile surfaces were observed. Gaps aligned with the flow were observed to promote boundary layer transition. Heat transfer correlation equations were obtained for many of the tests. The TPS thickness requirements with and without gaps were computed for a current shuttle entry trajectory. Experimental data employed in the study are summarized. A description of each test facility, run schedule and test conditions, model descriptive information, and heat flux data are included.

Origin of band gap bowing in dilute GaAs1-xNx and GaP1-xNx alloys: A real-space view

NASA Astrophysics Data System (ADS)

Virkkala, Ville; Havu, Ville; Tuomisto, Filip; Puska, Martti J.

2013-07-01

The origin of the band gap bowing in dilute nitrogen doped gallium based III-V semiconductors is largely debated. In this paper we show the dilute GaAs1-xNx and GaP1-xNx as representative examples that the nitrogen-induced states close to the conduction band minimum propagate along the zigzag chains on the {110} planes. Thereby states originating from different N atoms interact with each other resulting in broadening of the nitrogen-induced states which narrows the band gap. Our modeling based on ab initio theoretical calculations explains the experimentally observed N concentration dependent band gap narrowing both qualitatively and quantitatively.

Simultaneous band-gap narrowing and carrier-lifetime prolongation of organic–inorganic trihalide perovskites

PubMed Central

Kong, Lingping; Liu, Gang; Gong, Jue; Hu, Qingyang; Schaller, Richard D.; Dera, Przemyslaw; Zhang, Dongzhou; Liu, Zhenxian; Yang, Wenge; Zhu, Kai; Tang, Yuzhao; Wang, Chuanyi; Wei, Su-Huai; Xu, Tao; Mao, Ho-kwang

2016-01-01

The organic–inorganic hybrid lead trihalide perovskites have been emerging as the most attractive photovoltaic materials. As regulated by Shockley–Queisser theory, a formidable materials science challenge for improvement to the next level requires further band-gap narrowing for broader absorption in solar spectrum, while retaining or even synergistically prolonging the carrier lifetime, a critical factor responsible for attaining the near-band-gap photovoltage. Herein, by applying controllable hydrostatic pressure, we have achieved unprecedented simultaneous enhancement in both band-gap narrowing and carrier-lifetime prolongation (up to 70% to ∼100% increase) under mild pressures at ∼0.3 GPa. The pressure-induced modulation on pure hybrid perovskites without introducing any adverse chemical or thermal effect clearly demonstrates the importance of band edges on the photon–electron interaction and maps a pioneering route toward a further increase in their photovoltaic performance. PMID:27444014

The Home/School Connection and Its Role in Narrowing the Academic Achievement Gap: An Ecological Systems Theoretical Perspective

ERIC Educational Resources Information Center

Blandin, Allyson

2017-01-01

This literature review seeks to evaluate previous studies on the topic of the home/school connection and its role in enhancing students' academic achievement and narrowing the academic achievement gap. The ecological systems theory framework will facilitate the discussion of the importance of the home/school connection phenomenon. Perspectives…

Tackling Disadvantage: What Works in Narrowing the Achievement Gap in Schools

ERIC Educational Resources Information Center

Demie, Feyisa; Mclean, Christabel

2015-01-01

This study examines the success factors behind narrowing the achievement gap of disadvantaged pupils who are entitled to free school meals. A complementary methodological approach including a case study and focus group were used to explore performance and the views of teachers, parents and pupils. The key criteria for the selection of schools were…

Photography as a Means of Narrowing the Gap between Physics and Students

ERIC Educational Resources Information Center

Bagno, Esther; Eylon, Bat-Sheva; Levy, Smadar

2007-01-01

Many teachers would agree that not all their A-level students appreciate the beauty of physics or enjoy solving complex problems. In this article, we describe a photo-contest activity aimed at narrowing the gap between physics and students. The photo contest, involving both students and teachers, is guided by the National Center of Physics…

Narrowing the Gap in Outcomes: Further Overview of Data and Evidence on the ECM Outcomes for Vulnerable Groups. Progress Report and Update

ERIC Educational Resources Information Center

Morris, Marian; Easton, Claire

2008-01-01

Narrowing the Gap (NtG) is a two-year development and research programme, funded by the Department for Children, Schools and Families (DCSF) and the Local Government Association (LGA), working in partnership with other agencies, including local authorities. It seeks to make a significant difference, on a national scale, to the performance of…

A More Nuanced Approach to the Fourth Estate

DTIC Science & Technology

2012-05-17

School of Journalism, 2004. Shepard , Alicia C. Narrowing the Gap - Military, Media and the Iraq War - Cantigny Conference Series. Chicago : The McCormick...wary of access pledge, Chicago Tribune, January 26, 2003. http://articles.chicagotribune.com/2003-01- 26/news/0301260301_1_gulf-war-iraq-vietnam-war...http://www.defense.gov/transcripts/transcript.aspx?transcriptid=2476 (accessed September 17, 2011). 149 Alicia C. Shepard , Narrowing the Gap

In One Voice: Mainstream and ELL Teachers Work Side-by-Side in the Classroom, Teaching Language through Content

ERIC Educational Resources Information Center

Pardini, Priscilla

2006-01-01

Narrowing the achievement gap between students who are native English speakers and those learning English as a second language is one of the biggest challenges facing U.S. educators. This article discusses the approaches used by the Saint Paul (Minn.) Public Schools in narrowing this achievement gap. Saint Paul (Minn.) Public Schools has one of…

Electronic characterization of defects in narrow gap semiconductors

NASA Technical Reports Server (NTRS)

Patterson, James D.

1993-01-01

The study of point defects in semiconductors has a long and honorable history. In particular, the detailed understanding of shallow defects in common semiconductors traces back to the classic work of Kohn and Luttinger. However, the study of defects in narrow gap semiconductors represents a much less clear story. Here, both shallow defects (caused by long range potentials) and deep defects (from short range potentials) are far from being completely understood. In this study, all results are calculational and our focus is on the chemical trend of deep levels in narrow gap semiconductors. We study substitutional (including antisite), interstitial and ideal vacancy defects. For substitutional and interstitial impurities, the efects of relaxation are included. For materials like Hg(1-x)Cd(x)Te, we study how the deep levels vary with x, of particular interest is what substitutional and interstitial atoms yield energy levels in the gap i.e. actually produce deep ionized levels. Also, since the main technique utilized is Green's functions, we include some summary of that method.

Disability prevalence and disability-related employment gaps in the UK 1998-2012: Different trends in different surveys?

PubMed

Baumberg, Ben; Jones, Melanie; Wass, Victoria

2015-09-01

The persistently low employment rate among disabled individuals has been an enduring concern of governments across developed countries and has been the subject of a succession of policy initiatives, including labour market activation programmes, equality laws and welfare reform. A key indicator of progress is the trend in the disability-related employment gap, the percentage point difference between the employment rate for disabled and non-disabled individuals. Confusingly for the UK, studies undertaken between 1998 and 2012 have simultaneously reported both a widening and a narrowing of the gap. The source of the discrepancy can be found in the choice of survey, the General Household Survey (GHS) or the Labour Force Survey (LFS), although both use a common conception of disability and collect self-reported information from a random sample of households. The literature has analysed these surveys separately from each other and ignored inter-survey differences in findings. The Health Survey for England (HSE), a third national household survey, replicates the GHS questions on disability but has had limited use in this context. This empirical study compares the trends in disability prevalence and the disability-related employment gap across the three surveys using a three-stage harmonisation process. The negative relationship between the prevalence of disability and the employment gap found in cross-section inter-survey comparisons prompts an initial focus on differences in the definition of disability as an explanation of the discrepancy. This is broadened to include differences in survey methods and sample composition. Differences in the trend in disability prevalence and the employment gap remain following harmonisation for definition, survey method and sample composition. It is the LFS, the main policy-influencing and policy-assessment survey, which generates outlying results. As such, we cannot be confident that the disability-related employment gap has narrowed in the UK since 1998. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Inter-band optoelectronic properties in quantum dot structure of low band gap III-V semiconductors

NASA Astrophysics Data System (ADS)

Dey, Anup; Maiti, Biswajit; Chanda Sarkar, Debasree

2014-04-01

A generalized theory is developed to study inter-band optical absorption coefficient (IOAC) and material gain (MG) in quantum dot structures of narrow gap III-V compound semiconductor considering the wave-vector (k→) dependence of the optical transition matrix element. The band structures of these low band gap semiconducting materials with sufficiently separated split-off valance band are frequently described by the three energy band model of Kane. This has been adopted for analysis of the IOAC and MG taking InAs, InSb, Hg1-xCdxTe, and In1-xGaxAsyP1-y lattice matched to InP, as example of III-V compound semiconductors, having varied split-off energy band compared to their bulk band gap energy. It has been found that magnitude of the IOAC for quantum dots increases with increasing incident photon energy and the lines of absorption are more closely spaced in the three band model of Kane than those with parabolic energy band approximations reflecting the direct the influence of energy band parameters. The results show a significant deviation to the MG spectrum of narrow-gap materials having band nonparabolicity compared to the parabolic band model approximations. The results reflect the important role of valence band split-off energies in these narrow gap semiconductors.

A Quasi-Classical Model of the Hubbard Gap in Lightly Compensated Semiconductors

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

Poklonski, N. A.; Vyrko, S. A.; Kovalev, A. I.

2016-03-15

A quasi-classical method for calculating the narrowing of the Hubbard gap between the A{sup 0} and A{sup +} acceptor bands in a hole semiconductor or the D{sup 0} and D{sup –} donor bands in an electron semiconductor is suggested. This narrowing gives rise to the phenomenon of a semiconductor transition from the insulator to metal state with an increase in doping level. The major (doping) impurity can be in one of three charge states (–1, 0, or +1), while the compensating impurity can be in states (+1) or (–1). The impurity distribution over the crystal is assumed to be randommore » and the width of Hubbard bands (levels), to be much smaller than the gap between them. It is shown that narrowing of the Hubbard gap is due to the formation of electrically neutral acceptor (donor) states of the quasicontinuous band of allowed energies for holes (electrons) from excited states. This quasicontinuous band merges with the top of the valence band (v band) for acceptors or with the bottom of the conduction band (c band) for donors. In other words, the top of the v band for a p-type semiconductor or the bottom of the c band for an n-type semiconductor is shifted into the band gap. The value of this shift is determined by the maximum radius of the Bohr orbit of the excited state of an electrically neutral major impurity atom, which is no larger than half the average distance between nearest impurity atoms. As a result of the increasing dopant concentration, the both Hubbard energy levels become shallower and the gap between them narrows. Analytical formulas are derived to describe the thermally activated hopping transition of holes (electrons) between Hubbard bands. The calculated gap narrowing with increasing doping level, which manifests itself in a reduction in the activation energy ε{sub 2} is consistent with available experimental data for lightly compensated p-Si crystals doped with boron and n-Ge crystals doped with antimony.« less

Facile doping of anionic narrow-band-gap conjugated polyelectrolytes during dialysis.

PubMed

Mai, Cheng-Kang; Zhou, Huiqiong; Zhang, Yuan; Henson, Zachary B; Nguyen, Thuc-Quyen; Heeger, Alan J; Bazan, Guillermo C

2013-12-02

PCPDTBTSO3 K, an anionic, narrow-band-gap conjugated polyelectrolyte, was found to be doped after dialysis. The proposed doping mechanism involves protonation of the polymer backbone, followed by electron transfer from a neutral chain, to generate radical cations, which are stabilized by the pendant sulfonate anions. Formation of polarons is supported by spectroscopy and electrical-conductivity measurements. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Narrowing the Gender Gap:Empowering Women through Literacy Programmes: Case Studies from the UNESCO Effective Literacy and Numeracy Practices Database (LitBase) http://www.unesco.org/uil/litbase/. 2nd Edition

ERIC Educational Resources Information Center

Hanemann, Ulrike, Ed.

2015-01-01

UIL has published a second edition of a collection of case studies of promising literacy programmes that seek to empower women. "Narrowing the Gender Gap: Empowering Women through Literacy Programmes" (originally published in 2013 as "Literacy Programmes with a Focus on Women to Reduce Gender Disparities") responds to the…

The strain induced band gap modulation from narrow gap semiconductor to half-metal on Ti{sub 2}CrGe: A first principles study

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

Li, Jia, E-mail: jiali@hebut.edu.cn; Research Institute for Energy Equipment Materials, Hebei University of Technology, Tianjin 300401; Zhang, Zhidong

The Heusler alloy Ti{sub 2}CrGe is a stable L2{sub 1} phase with antiferromagnetic ordering. With band-gap energy (∼ 0.18 eV) obtained from a first-principles calculation, it belongs to the group of narrow band gap semiconductor. The band-gap energy decreases with increasing lattice compression and disappears until a strain of −5%; moreover, gap contraction only occurs in the spin-down states, leading to half-metallic character at the −5% strain. The Ti{sub 1}, Ti{sub 2}, and Cr moments all exhibit linear changes in behavior within strains of −5%– +5%. Nevertheless, the total zero moment is robust for these strains. The imaginary part ofmore » the dielectric function for both up and down spin states shows a clear onset energy, indicating a corresponding electronic gap for the two spin channels.« less

Diluted magnetic semiconductors with narrow band gaps

NASA Astrophysics Data System (ADS)

Gu, Bo; Maekawa, Sadamichi

2016-10-01

We propose a method to realize diluted magnetic semiconductors (DMSs) with p - and n -type carriers by choosing host semiconductors with a narrow band gap. By employing a combination of the density function theory and quantum Monte Carlo simulation, we demonstrate such semiconductors using Mn-doped BaZn2As2 , which has a band gap of 0.2 eV. In addition, we found a nontoxic DMS Mn-doped BaZn2Sb2 , of which the Curie temperature Tc is predicted to be higher than that of Mn-doped BaZn2As2 , the Tc of which was up to 230 K in a recent experiment.

Impurity-induced photoconductivity of narrow-gap Cadmium–Mercury–Telluride structures

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

Kozlov, D. V., E-mail: dvkoz@impras.ru; Rumyantsev, V. V.; Morozov, S. V.

2015-12-15

The photoconductivity (PC) spectra of CdHgTe (MCT) solid solutions with a Cd fraction of 17 and 19% are measured. A simple model for calculating the states of doubly charged acceptors in MCT solid solutions, which makes it possible to describe satisfactorily the observed photoconductivity spectra, is proposed. The found lines in the photoconductivity spectra of narrow-gap MCT structures are associated with transitions between the states of both charged and neutral acceptor centers.

Closing the Achievement Gap: Four States' Efforts

ERIC Educational Resources Information Center

Wixom, Micah Ann

2015-01-01

The achievement gap separating economically disadvantaged students from their more advantaged peers disproportionately affects students of color and has been the focus of discussion, research and controversy for more than 40 years. While the gap between black and white students narrowed considerably from the 1950s to the 1980s, that gap has…

The Vector Calculus Gap: Mathematics (Does Not Equal) Physics.

ERIC Educational Resources Information Center

Dray, Tevian; Manogue, Corinne A.

1999-01-01

Discusses some of the differences between the ways mathematicians and physicists view vector calculus and the gap between the way this material is traditionally taught by mathematicians and the way physicists use it. Suggests some ways to narrow the gap. (Author/ASK)

High-Voltage Breakdown Penalties for the Beam-Breakup Instability

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

Ekdahl, Carl August

2016-11-22

The strength of the dangerous beam breakup (BBU) instability in linear induction accelerators (LIAs) is determined by the transverse coupling impedance Z ⊥ of the induction cell cavity. For accelerating gap width w less than the beam pipe radius b, the transverse impedance is theoretically proportional to w/b, favoring narrow gaps to suppress BBU. On the other hand, cells with narrow gaps cannot support high accelerating gradients, because of electrical breakdown and shorting of the gap. Thus, there is an engineering trade-off between BBU growth and accelerating gradient, which must be considered for next generation LIAs now being designed. Inmore » this article this tradeoff is explored, using a simple pillbox cavity as an illustrative example. For this model, widening the gap to reduce the probability of breakdown increases BBU growth, unless higher magnetic focusing fields are used to further suppress the instability.« less

Narrow Band Gap Lead Sulfide Hole Transport Layers for Quantum Dot Photovoltaics.

PubMed

Zhang, Nanlin; Neo, Darren C J; Tazawa, Yujiro; Li, Xiuting; Assender, Hazel E; Compton, Richard G; Watt, Andrew A R

2016-08-24

The band structure of colloidal quantum dot (CQD) bilayer heterojunction solar cells is optimized using a combination of ligand modification and QD band gap control. Solar cells with power conversion efficiencies of up to 9.33 ± 0.50% are demonstrated by aligning the absorber and hole transport layers (HTL). Key to achieving high efficiencies is optimizing the relative position of both the valence band and Fermi energy at the CQD bilayer interface. By comparing different band gap CQDs with different ligands, we find that a smaller band gap CQD HTL in combination with a more p-type-inducing CQD ligand is found to enhance hole extraction and hence device performance. We postulate that the efficiency improvements observed are largely due to the synergistic effects of narrower band gap QDs, causing an upshift of valence band position due to 1,2-ethanedithiol (EDT) ligands and a lowering of the Fermi level due to oxidation.

Success and failure in narrowing the disability employment gap: comparing levels and trends across Europe 2002-2014.

PubMed

Geiger, Ben Baumberg; van der Wel, Kjetil A; Tøge, Anne Grete

2017-12-02

International comparisons of the disability employment gap are an important driver of policy change. However, previous comparisons have used the European Union Statistics on Income and Living Conditions (EU-SILC), despite known comparability issues. We present new results from the higher-quality European Social Survey (ESS), compare these to EU-SILC and the EU Labour Force Survey (EU-LFS), and also examine trends in the disability employment gap in Europe over the financial crisis for the first time. For cross-sectional comparisons of 25 countries, we use micro-data for ESS and EU-SILC for 2012 and compare these to published EU-LFS 2011 estimates. For trend analyses, we use seven biannual waves of ESS (2002-2014) with a total sample size of 182,195, and annual waves of EU-SILC (2004-2014) with a total sample size of 2,412,791. (i) Cross-sectional: countries that have smaller disability employment gaps in one survey tend to have smaller gaps in the other surveys. Nevertheless, there are some countries that perform badly on the lower-quality surveys but better in the higher-quality ESS. (ii) Trends: the disability employment gap appears to have declined in ESS by 4.9%, while no trend is observed in EU-SILC - but this has come alongside a rise in disability in ESS. There is a need for investment in disability measures that are more comparable over time/space. Nevertheless, it is clear to policymakers there are some countries that do consistently well across surveys and measures (Switzerland), and others that do badly (Hungary).

Pseudomorphic Narrow Gap Materials for High Performance Devices

DTIC Science & Technology

1993-04-14

research under this program is ito obtain hiigh quality pseudomorphic (strained) narrow gap materials for high performance device applicatjons During...1993 ELECTE """ ’I ~01lG:9395 APR21 W93 Dr. Max N. Yoder Scientific Officer, Code 114SS Office of Naval Research 800 N. Quincy Street Arlington, VA...Mr. V. Morano - w/cy each/ ...- Administrative Grants Officer Office of Naval Research . r. - Resident Representative, N6Z9g7 -- _ z 33 Third Avenue

Band gap narrowing in BaTiO{sub 3} nanoparticles facilitated by multiple mechanisms

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

Ramakanth, S.; James Raju, K. C., E-mail: kcjrsp@uohyd.ernet.in; School of Physics, University of Hyderabad, Hyderabad 500046

2014-05-07

In the present work, BaTiO{sub 3} nanoparticles of four different size ranges were prepared by sol-gel method. The optical band gap of these particles at some size ranges has come down to 2.53 eV from 3.2 eV, resulting in substantial increase in optical absorption by these ferroelectric nanoparticles making them potential candidates for light energy harvesting. XRD results show the presence of higher compressive strain in 23 nm and 54 nm size particles, they exhibit a higher band gap narrowing, whereas tensile strain is observed in 31 nm and 34 nm particles, and they do not show the marginal band gap narrowing. The 23 nm and 54 nmmore » particles also show a coupling of free carriers to phonons by increasing the intensity of LO phonon mode at 715 cm{sup −1}. The higher surface charge density is expected in case of enhanced surface optical Raman modes (638 cm{sup −1}) contained in 31 and 34 nm size particles. In addition to this, the red shift in an LO mode Raman spectral line at 305 cm{sup −1} with decrease in particle size depicts the presence of phonon confinement in it. The enhanced optical absorption in 23 nm and 54 nm size particles with a narrowed band gap of 3 eV and 2.53 eV is due to exchange correlation interactions between the carriers present in these particles. In 31 nm and 34 nm range particles, the absorption got bleached exhibiting increased band gaps of 3.08 eV and 3.2 eV, respectively. It is due to filling up of conduction band resulting from weakening of exchange correlation interactions between the charge carriers. Hence, it is concluded that the band gap narrowing in the nanoparticles of average size 23 nm/54 nm is a consequence of multiple effects like strain, electron-phonon interaction, and exchange correlation interactions between the carriers which is subdued in some other size ranges like 31 nm/34 nm.« less

Socioeconomic dynamics of gender disparity in childhood immunization in India, 1992-2006.

PubMed

Prusty, Ranjan Kumar; Kumar, Abhishek

2014-01-01

Recent evidence indicated that gender disparity in child health is minimal and narrowed over time in India. However, considering the geographical and socio-cultural diversity in India, the gender gap may persist across disaggregated socioeconomic context which may be masked by average level. This study examines the dynamics of gender disparity in childhood immunization across regions, residence, wealth, caste and religion in India during 1992-2006. We used multi-waves of the cross-sectional data of National Family Health Survey conducted in India between 1992-93 and 2005-06. Gender disparity ratio was used to measure the gender gap in childhood immunization across the selected socioeconomic characteristics. Multinomial regression analysis was used to examine the gender gap after accounting for other covariates. Results indicate that, at aggregate level, gender disparity in full immunization is minimal and has stagnated during the study period. However, gender disparity--disfavouring female children--becomes apparent across the regions, poor households, and religion--particularly among Muslims. Adjusted gender disparity ratio indicates that, full immunization is lower among female than male children of the western region, poor household and among Muslims. Between 1992-93 and 2005-06, the disparity in full immunization had narrowed in the northern region whereas it had, astonishingly, increased in some of the western and southern states of the country. Our findings emphasize the need to integrate gender issues in the ongoing immunization programme in India, with particular attention to urban areas, developed states, and to the Muslim community.

Nanodopant-Induced Band Modulation in AgPbmSbTe2+m-Type Nanocomposites

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

Zhang, Yi; Ke, Xuezhi; Chen, Changfeng

2011-01-01

We elucidate the fundamental physics of nanoscale dopants in narrow band-gap thermoelectric nanocomposites XPbmYTe2+m (X=Ag,Na; Y=Sb,Bi) using first-principles calculations. Our re- sults unveil distinct band-structure modulations, most notably a sizable band-gap widening driven by nanodopant-induced lattice strain and a band split-off at the conduction band minimum caused by the spin-orbit interaction of the dopant Sb or Bi atoms. Boltzmann transport calculations demon- strate that these band modulations have significant but competing effects on high-temperature elec- tron transport behavior. These results offer insights for understanding recent experimental findings and suggest principles for optimizing thermoelectric properties of narrow band-gap semiconductors.

Broadening of effective photonic band gaps in biological chiral structures: From intrinsic narrow band gaps to broad band reflection spectra

NASA Astrophysics Data System (ADS)

Vargas, W. E.; Hernández-Jiménez, M.; Libby, E.; Azofeifa, D. E.; Solis, Á.; Barboza-Aguilar, C.

2015-09-01

Under normal illumination with non-polarized light, reflection spectra of the cuticle of golden-like and red Chrysina aurigans scarabs show a structured broad band of left-handed circularly polarized light. The polarization of the reflected light is attributed to a Bouligand-type left-handed chiral structure found through the scarab's cuticle. By considering these twisted structures as one-dimensional photonic crystals, a novel approach is developed from the dispersion relation of circularly polarized electromagnetic waves traveling through chiral media, to show how the broad band characterizing these spectra arises from an intrinsic narrow photonic band gap whose spectral position moves through visible and near-infrared wavelengths.

Band structures of TiO2 doped with N, C and B*

PubMed Central

Xu, Tian-Hua; Song, Chen-Lu; Liu, Yong; Han, Gao-Rong

2006-01-01

This study on the band structures and charge densities of nitrogen (N)-, carbon (C)- and boron (B)-doped titanium dioxide (TiO2) by first-principles simulation with the CASTEP code (Segall et al., 2002) showed that the three 2p bands of impurity atom are located above the valence-band maximum and below the Ti 3d bands, and that along with the decreasing of impurity atomic number, the fluctuations become more intensive. We cannot observe obvious band-gap narrowing in our result. Therefore, the cause of absorption in visible light might be the isolated impurity atom 2p states in band-gap rather than the band-gap narrowing. PMID:16532532

Shape-controlled narrow-gap SnTe nanostructures: From nanocubes to nanorods and nanowires

DOE PAGES

Guo, Shaojun; Andrew F. Fidler; He, Kai; ...

2015-11-06

In this study, the rational design and synthesis of narrow-gap colloidal semiconductor nanocrystals (NCs) is an important step toward the next generation of solution-processable photovoltaics, photodetectors, and thermoelectric devices. SnTe NCs are particularly attractive as a Pb-free alternative to NCs of narrow-gap lead chalcogenides. Previous synthetic efforts on SnTe NCs have focused on spherical nanoparticles. Here we report new strategies for synthesis of SnTe NCs with shapes tunable from highly monodisperse nanocubes, to nanorods (NRs) with variable aspect ratios, and finally to long, straight nanowires (NWs). Reaction at high temperature quickly forms thermodynamically favored nanocubes, but low temperatures lead tomore » elongated particles. Transmission electron microscopy studies of reaction products at various stages of the synthesis reveal that the growth and shape-focusing of monodisperse SnTe nanocubes likely involves interparticle ripening, while directional growth of NRs and NWs may be initiated by particle dimerization via oriented attachment.« less

Evidence for Itinerant Carriers in an Anisotropic Narrow-Gap Semiconductor by Angle-Resolved Photoemission Spectroscopy.

PubMed

Ju, Sailong; Bai, Wei; Wu, Liming; Lin, Hua; Xiao, Chong; Cui, Shengtao; Li, Zhou; Kong, Shuai; Liu, Yi; Liu, Dayong; Zhang, Guobin; Sun, Zhe; Xie, Yi

2018-01-01

The ability to accurately determine the electronic structure of solids has become a key prerequisite for modern functional materials. For example, the precise determination of the electronic structure helps to balance the three thermoelectric parameters, which is the biggest challenge to design high-performance thermoelectric materials. Herein, by high-resolution, angle-resolved photoemission spectroscopy (ARPES), the itinerant carriers in CsBi 4 Te 6 (CBT) are revealed for the first time. CBT is a typical anisotropic, narrow-gap semiconductor used as a practical candidate for low-temperature thermoelectric applications, and p-doped CBT series show superconductivity at relatively low carrier concentrations. The ARPES results show a significantly larger bandwidth near the Fermi surface than calculations, which means the carriers transport anisotropically and itinerantly in CBT. It is reasonable to believe that these newly discovered features of carriers in narrow-gap semiconductors are promising for designing optimal thermoelectric materials and superconductors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Narrowing of band gap at source/drain contact scheme of nanoscale InAs-nMOS

NASA Astrophysics Data System (ADS)

Mohamed, A. H.; Oxland, R.; Aldegunde, M.; Hepplestone, S. P.; Sushko, P. V.; Kalna, K.

2018-04-01

A multi-scale simulation study of Ni/InAs nano-scale contact aimed for the sub-14 nm technology is carried out to understand material and transport properties at a metal-semiconductor interface. The deposited Ni metal contact on an 11 nm thick InAs channel forms an 8.5 nm thick InAs leaving a 2.5 nm thick InAs channel on a p-type doped (1 × 1016 cm-3) AlAs0.47Sb0.53 buffer. The density functional theory (DFT) calculations reveal a band gap narrowing in the InAs at the metal-semiconductor interface. The one-dimensional (1D) self-consistent Poisson-Schrödinger transport simulations using real-space material parameters extracted from the DFT calculations at the metal-semiconductor interface, exhibiting band gap narrowing, give a specific sheet resistance of Rsh = 90.9 Ω/sq which is in a good agreement with an experimental value of 97 Ω/sq.

Productive Pedagogies: Narrowing the Gap between Schools and Communities?

ERIC Educational Resources Information Center

Leat, David; Thomas, Ulrike

2016-01-01

There is little sign that current attempts to close the "attainment gap" are working. This article argues for a different approach to addressing the "gap," based on a community asset approach. The authors describe ongoing work on community curriculum making in North-East England, in which schools undertake projects using…

FINAL REPORT ON GDE GAP CELL

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

Herman, D.; Summers, W.; Danko, E.

2009-09-28

A project has been undertaken to develop an electrochemical cell and support equipment for evaluation of a gas diffusion electrode-based, narrow-electrolyte-gap anode for SO{sub 2} oxidation in the hydrogen production cycle of the hybrid sulfur (HyS) process. The project supported the HyS development program at the Savannah River National Lab (SRNL). The benefits of using a gas diffusion electrode in conjunction with the narrow anolyte gap are being determined through electrochemical polarization testing under a variety conditions, and by comparison to results produced by SRNL and others using anode technologies that have no anolyte gap. These test results indicate thatmore » the NGA cell has low resistance suitable for use in the HyS electrolyzer, exhibits good efficiency at high current densities compared to the direct feed HyS electrolyzer, and indicates robust performance in extended testing over 65 hours. Seepage episodes were mostly caused by port clogging, which can be mitigated in future designs through minor modifications to the hardware. Significant reductions in sulfur crossover have not yet been demonstrated in the NGA configuration compared to in-house direct feed testing, but corroborative sulfur layer analysis is as yet incomplete. Further testing in a single-pass anolyte configuration is recommended for complete evaluation of steady-state electrochemical efficiency and SO{sub 2} crossover in the narrow gap configuration.« less

The gap in scientific knowledge and role of science communication in South Korea.

PubMed

Chang, Jeong-Heon; Kim, Sei-Hill; Kang, Myung-Hyun; Shim, Jae Chul; Ma, Dong Hoon

2017-01-01

Using data from a national survey of South Koreans, this study explores the role of science communication in enhancing three different forms of scientific knowledge ( factual, procedural, and subjective). We first assess learning effects, looking at the extent to which citizens learn science from different channels of communication (interpersonal discussions, traditional newspapers, television, online newspapers, and social media). We then look into the knowledge gap hypothesis, investigating how different communication channels can either widen or narrow the gap in knowledge between social classes. Television was found to function as a "knowledge leveler," narrowing the gap between highly and less educated South Koreans. The role of online newspapers in science learning is pronounced in our research. Reading newspapers online indicated a positive relationship to all three measures of knowledge. Contrary to the knowledge-leveling effect of television viewing, reading online newspapers was found to increase, rather than decrease, the gap in knowledge. Implications of our findings are discussed in detail.

Giant Hall Photoconductivity in Narrow-Gapped Dirac Materials

NASA Astrophysics Data System (ADS)

Song, Justin C. W.; Kats, Mikhail A.

2016-12-01

Carrier dynamics acquire a new character in the presence of Bloch-band Berry curvature, which naturally arises in gapped Dirac materials (GDMs). Here we argue that photoresponse in GDMs with small band gaps is dramatically enhanced by Berry curvature. This manifests in a giant and saturable Hall photoconductivity when illuminated by circularly polarized light. Unlike Hall motion arising from a Lorentz force in a magnetic field, which impedes longitudinal carrier motion, Hall photoconductivity arising from Berry curvature can boost longitudinal carrier transport. In GDMs, this results in a helicity-dependent photoresponse in the Hall regime, where photoconductivity is dominated by its Hall component. We find that the induced Hall conductivity per incident irradiance is enhanced by up to six orders of magnitude when moving from the visible regime (with corresponding band gaps) to the far infrared. These results suggest that narrow-gap GDMs are an ideal test-bed for the unique physics that arise in the presence of Berry curvature, and open a new avenue for infrared and terahertz optoelectronics.

Whose Problem Is Poverty?

ERIC Educational Resources Information Center

Rothstein, Richard

2008-01-01

Closing or substantially narrowing achievement gaps requires combining school improvement with reforms to narrow the vast socioeconomic inequalities in the United States. Recognizing the effects of socioeconomic disparities on student learning is not "making excuses" for poor instruction or "letting schools off the hook" for raising student…

Bridging the Civil Military Gap Capitalizing on Crisis

DTIC Science & Technology

2002-01-01

solutions. Researchers identifying the sources of the gap discussed above, have also suggested some methods for reducing the gap . While some are policy...Strategy Research Project DATE: 09 April 2002 PAGES: 42 CLASSIFICATION: Unclassified Researchers have identified a "civil-military gap ," an observable...would indicate a desire by the civilian populous to draw closer to the military, creating an opportunity to close or at least narrow this gap . The media

Understanding the Gender Gap.

ERIC Educational Resources Information Center

Goldin, Claudia

1985-01-01

Despite the great influx of women into the labor market, the gap between men's and women's wages has remained stable at 40 percent since 1950. Analysis of labor data suggests that this has occurred because women's educational attainment compared to men has declined. Recently, however, the wage gap has begun to narrow, and this will probably become…

Ultra-Smooth ZnS Films Grown on Silicon via Pulsed Laser Deposition

NASA Astrophysics Data System (ADS)

Reidy, Christopher; Tate, Janet

2011-10-01

Ultra-smooth, high quality ZnS films were grown on (100) and (111) oriented Si wafers via pulsed laser deposition with a KrF excimer laser in UHV (10-9 Torr). The resultant films were examined with optical spectroscopy, electron diffraction, and electron probe microanalysis. The films have an rms roughness of ˜1.5 nm, and the film stoichiometry is approximately Zn:S :: 1:0.87. Additionally, each film exhibits an optical interference pattern which is not a function of probing location on the sample, indicating excellent film thickness uniformity. Motivation for high-quality ZnS films comes from a proposed experiment to measure carrier amplification via impact ionization at the boundary between a wide-gap and a narrow-gap semiconductor. If excited charge carriers in a sufficiently wide-gap harvester can be extracted into a narrow-gap host material, impact ionization may occur. We seek near-perfect interfaces between ZnS, with a direct gap between 3.3 and 3.7 eV, and Si, with an indirect gap of 1.1 eV.

Enhancing catalytic activity by narrowing local energy gaps--X-ray studies of a manganese water oxidation catalyst.

PubMed

Xiao, Jie; Khan, Munirah; Singh, Archana; Suljoti, Edlira; Spiccia, Leone; Aziz, Emad F

2015-03-01

Changes in the local electronic structure of the Mn 3d orbitals of a Mn catalyst derived from a dinuclear Mn(III) complex during the water oxidation cycle were investigated ex situ by X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) analyses. Detailed information about the Mn 3d orbitals, especially the local HOMO-LUMO gap on Mn sites revealed by RIXS analyses, indicated that the enhancement in catalytic activity (water oxidation) originated from the narrowing of the local HOMO-LUMO gap when electrical voltage and visible light illumination were applied simultaneously to the Mn catalytic system. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Makarov, Nikolay S.; Lin, Qianglu; Pietryga, Jeffrey M.

One source of efficiency losses in photovoltaic cells is their transparency toward solar photons with energies below the band gap of the absorbing layer. This loss can be reduced using a process of up-conversion whereby two or more sub-band-gap photons generate a single above-gap exciton. Traditional approaches to up-conversion, such as nonlinear two-photon absorption (2PA) or triplet fusion, suffer from low efficiency at solar light intensities, a narrow absorption bandwidth, nonoptimal absorption energies, and difficulties for implementing in practical devices. We show that these deficiencies can be alleviated using the effect of Auger up-conversion in thick-shell PbSe/CdSe quantum dots. Thismore » process relies on Auger recombination whereby two low-energy, core-based excitons are converted into a single higher-energy, shell-based exciton. When compared to their monocomponent counterparts, the tailored PbSe/CdSe heterostructures feature enhanced absorption cross-sections, a higher efficiency of the “productive” Auger pathway involving re-excitation of a hole, and longer lifetimes of both core- and shell-localized excitons. These features lead to effective up-conversion cross-sections that are more than 6 orders of magnitude higher than for standard nonlinear 2PA, which allows for efficient up-conversion of continuous wave infrared light at intensities as low as a few watts per square centimeter.« less

An ultrastructural analysis of the epithelial-fiber interface (EFI) in primate lenses.

PubMed

Kuszak, J R; Novak, L A; Brown, H G

1995-11-01

The purpose of this study was to conduct a comprehensive ultrastructural analysis of the epithelial-fiber interface (EFI) in normal adult primate (Macaque nemestrina and fascicularis; 6-9 years old, n = 10) lenses. Scanning electron microscopy (SEM) was used to initially characterize the gross size, shape and three-dimensional organization of central zone (cz) epithelial cells and the anterior ends of elongating fibers beneath these cells. This fiducial information was essential to properly orient lens pieces in freeze fracture specimen carriers for the production of replicas with unambiguously identifiable EFI. Transmission electron microscopy (TEM) of replicas and thin-sectioned material were used to ultrastructurally analyse the cz EFI. TEM thin-sectioned material was also used to ultrastructurally analyse the pregerminative (pgz), germinative (gz) and transitional zone (tz) EFI. Correlative SEM and TEM of cz EFI components revealed that the apical membrane of both epithelial and elongating fiber cells were irregularly polygonal in shape, and aligned in parallel as smooth, concave-convex surfaces. However, whereas epithelial cell apical surfaces had minimal size variation, elongating fibers were larger and considerably variable in size. Quantitative analysis of > 10000 micron2 cz elongating fiber apical surfaces failed to detect any gap junctions defined in freeze fracture replicas as complementary aggregates of transmembrane proteins (connexons) conjoined across a narrowed extracellular space. However, a comparable frequency of vesicular events was noted in this region as quantified previously in adult and embryonic chick lens. Correlative TEM analysis > 1500 linear micrometers of thin-sectioned EFI from this region confirmed the presence of epithelial-epithelial gap junctions, elongating fiber-elongating fiber gap junctions, and an extreme paucity of epithelial-elongating fiber gap junctions. In contrast, TEM analysis of > 1000 linear micrometers of thin-sectioned pgz, gz and tz EFI, confirmed the presence of epithelial-epithelial gap junctions, elongating fiber-elongating fiber gap junctions, numerous epithelial-elongating fiber adherens junctions and a few epithelial-elongating fiber gap junctions. Thus, the results of this and previous quantitative morphological and physiological studies (electronic and dye coupling) demonstrate that there is limited coupling between cz epithelial cells and underlying elongating fibers. Furthermore, the absence of gap junctional plaques in cz EFI freeze-fracture replicas and either pentalaminar or septalaminar profiles in correlative thin-sections, suggests that this limited coupling could be mediated via isolated gap junction channels. However, the results of this and previous quantitative studies further show that a greater degree of coupling exists across the pgz, gz and tz regions of the EFI and that this coupling is likely to be mediated by gap junction plaques. Finally, this and other studies continue to demonstrate that transcytotic processes play a role in lens physiology at the EFI.

InGaP Heterojunction Barrier Solar Cells

NASA Technical Reports Server (NTRS)

Welser, Roger E. (Inventor)

2014-01-01

A new solar cell structure called a heterojunction barrier solar cell is described. As with previously reported quantum-well and quantum-dot solar cell structures, a layer of narrow band-gap material, such as GaAs or indium-rich InGaP, is inserted into the depletion region of a wide band-gap PN junction. Rather than being thin, however, the layer of narrow band-gap material is about 400-430 nm wide and forms a single, ultrawide well in the depletion region. Thin (e.g., 20-50 nm), wide band-gap InGaP barrier layers in the depletion region reduce the diode dark current. Engineering the electric field and barrier profile of the absorber layer, barrier layer, and p-type layer of the PN junction maximizes photogenerated carrier escape. This new twist on nanostructured solar cell design allows the separate optimization of current and voltage to maximize conversion efficiency.

High-Pressure Band-Gap Engineering in Lead-Free Cs 2 AgBiBr 6 Double Perovskite

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

Li, Qian; Wang, Yonggang; Pan, Weicheng

Novel inorganic lead-free double perovskites with improved stability are regarded as alternatives to state-of-art hybrid lead halide perovskites in photovoltaic devices. The recently discovered Cs2AgBiBr6 double perovskite exhibits attractive optical and electronic features, making it promising for various optoelectronic applications. However, its practical performance is hampered by the large band gap. In this work, remarkable band gap narrowing of Cs2AgBiBr6 is, for the first time, achieved on inorganic photovoltaic double perovskites through high pressure treatments. Moreover, the narrowed band gap is partially retainable after releasing pressure, promoting its optoelectronic applications. This work not only provides novel insights into the structure–propertymore » relationship in lead-free double perovskites, but also offers new strategies for further development of advanced perovskite devices.« less

Health Inequalities: Trends, Progress, and Policy

PubMed Central

Bleich, Sara N.; Jarlenski, Marian P.; Bell, Caryn N.; LaVeist, Thomas A.

2013-01-01

Health inequalities, which have been well documented for decades, have more recently become policy targets in developed countries. This review describes time trends in health inequalities (by sex, race/ethnicity, and socioeconomic status), commitments to reduce health inequalities, and progress made to eliminate health inequalities in the United States, United Kingdom, and other OECD countries. Time-trend data in the United States indicate a narrowing of the gap between the best- and worst-off groups in some health indicators, such as life expectancy, but a widening of the gap in others, such as diabetes prevalence. Similarly, time-trend data in the United Kingdom indicate a narrowing of the gap between the best- and worst-off groups in some indicators, such as hypertension prevalence, whereas the gap between social classes has increased for life expectancy. More research and better methods are needed to measure precisely the relationships between stated policy goals and observed trends in health inequalities. PMID:22224876

First-principles study of direct and narrow band gap semiconducting β -CuGaO 2

DOE PAGES

Nguyen, Manh Cuong; Zhao, Xin; Wang, Cai-Zhuang; ...

2015-04-16

Semiconducting oxides have attracted much attention due to their great stability in air or water and the abundance of oxygen. Recent success in synthesizing a metastable phase of CuGaO 2 with direct narrow band gap opens up new applications of semiconducting oxides as absorber layer for photovoltaics. Using first-principles density functional theory calculations, we investigate the thermodynamic and mechanical stabilities as well as the structural and electronic properties of the β-CuGaO 2 phase. Our calculations show that the β-CuGaO 2 structure is dynamically and mechanically stable. The energy band gap is confirmed to be direct at the Γ point ofmore » Brillouin zone. In conclusion, the optical absorption occurs right at the band gap edge and the density of states near the valance band maximum is large, inducing an intense absorption of light as observed in experiment.« less

Lonely Moon

NASA Image and Video Library

2016-10-17

Pandora is seen here, in isolation beside Saturn's kinked and constantly changing F ring. Pandora (near upper right) is 50 miles (81 kilometers) wide. The moon has an elongated, potato-like shape (see PIA07632). Two faint ringlets are visible within the Encke Gap, near lower left. The gap is about 202 miles (325 kilometers) wide. The much narrower Keeler Gap, which lies outside the Encke Gap, is maintained by the diminutive moon Daphnis (not seen here). This view looks toward the sunlit side of the rings from about 23 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 12, 2016. The view was acquired at a distance of approximately 907,000 miles (1.46 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 113 degrees. Image scale is 6 miles (9 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20504

Socioeconomic Dynamics of Gender Disparity in Childhood Immunization in India, 1992–2006

PubMed Central

Prusty, Ranjan Kumar; Kumar, Abhishek

2014-01-01

Background Recent evidence indicated that gender disparity in child health is minimal and narrowed over time in India. However, considering the geographical and socio-cultural diversity in India, the gender gap may persist across disaggregated socioeconomic context which may be masked by average level. This study examines the dynamics of gender disparity in childhood immunization across regions, residence, wealth, caste and religion in India during 1992–2006. Method We used multi-waves of the cross-sectional data of National Family Health Survey conducted in India between 1992–93 and 2005–06. Gender disparity ratio was used to measure the gender gap in childhood immunization across the selected socioeconomic characteristics. Multinomial regression analysis was used to examine the gender gap after accounting for other covariates. Result Results indicate that, at aggregate level, gender disparity in full immunization is minimal and has stagnated during the study period. However, gender disparity – disfavouring female children – becomes apparent across the regions, poor households, and religion - particularly among Muslims. Adjusted gender disparity ratio indicates that, full immunization is lower among female than male children of the western region, poor household and among Muslims. Between 1992–93 and 2005–06, the disparity in full immunization had narrowed in the northern region whereas it had, astonishingly, increased in some of the western and southern states of the country. Conclusion Our findings emphasize the need to integrate gender issues in the ongoing immunization programme in India, with particular attention to urban areas, developed states, and to the Muslim community. PMID:25127396

Electronic characterization of defects in narrow gap semiconductors: Comparison of electronic energy levels and formation energies in mercury cadmium telluride, mercury zinc telluride, and mercury zinc selenide

NASA Technical Reports Server (NTRS)

Patterson, James D.; Li, Wei-Gang

1995-01-01

The project has evolved to that of using Green's functions to predict properties of deep defects in narrow gap materials. Deep defects are now defined as originating from short range potentials and are often located near the middle of the energy gap. They are important because they affect the lifetime of charge carriers and hence the switching time of transistors. We are now moving into the arena of predicting formation energies of deep defects. This will also allow us to make predictions about the relative concentrations of the defects that could be expected at a given temperature. The narrow gap materials mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS) are of interest to NASA because they have commercial value for infrared detecting materials, and because there is a good possibility that they can be grown better in a microgravity environment. The uniform growth of these crystals on earth is difficult because of convection (caused by solute depletion just ahead of the growing interface, and also due to thermal gradients). In general it is very difficult to grow crystals with both radial and axial homogeneity.

Crystal Growth and Characterization of the Narrow-Band-Gap Semiconductors OsPn 2 (Pn = P, As, Sb)

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

Bugaris, Daniel E.; Malliakas, Christos D.; Shoemaker, Daniel P.

2014-09-15

Using metal fluxes, crystals of the binary osmium dipnictides OsPn(2) (Pn = P, As, Sb) have been grown for the first time. Single-crystal X-ray diffraction confirms that these compounds crystallize in the marcasite structure type with orthorhombic space group Pnnm. The structure is a three-dimensional framework of corner- and edge-sharing OsPn(6) octahedra, as well as [Pn(2)(-4)] anions. Raman spectroscopy shows the presence of PP single bonds, consistent with the presence of [Pn(2)(-4)] anions and formally Os4+ cations. Optical-band-gap and high-temperature electrical resistivity measurements indicate that these materials are narrow-band-gap semiconductors. The experimentally determined Seebeck coefficients reveal that nominally undoped OsP2more » and OsSb2 are n-type semiconductors, whereas OsAs2 is p-type. Electronic band structure using density functional theory calculations shows that these compounds are indirect narrow-band-gap semiconductors. The bonding p orbitals associated with the Pn(2) dimer are below the Fermi energy, and the corresponding antibonding states are above, consistent with a PnPn single bond. Thermopower calculations using Boltzmann transport theory and constant relaxation time approximation show that these materials are potentially good thermoelectrics, in agreement with experiment.« less

The effect of exchange interaction on quasiparticle Landau levels in narrow-gap quantum well heterostructures.

PubMed

Krishtopenko, S S; Gavrilenko, V I; Goiran, M

2012-04-04

Using the 'screened' Hartree-Fock approximation based on the eight-band k·p Hamiltonian, we have extended our previous work (Krishtopenko et al 2011 J. Phys.: Condens. Matter 23 385601) on exchange enhancement of the g-factor in narrow-gap quantum well heterostructures by calculating the exchange renormalization of quasiparticle energies, the density of states at the Fermi level and the quasiparticle g-factor for different Landau levels overlapping. We demonstrate that exchange interaction yields more pronounced Zeeman splitting of the density of states at the Fermi level and leads to the appearance of peak-shaped features in the dependence of the Landau level energies on the magnetic field at integer filling factors. We also find that the quasiparticle g-factor does not reach the maximum value at odd filling factors in the presence of large overlapping of spin-split Landau levels. We advance an argument that the behavior of the quasiparticle g-factor in weak magnetic fields is defined by a random potential of impurities in narrow-gap heterostructures. © 2012 IOP Publishing Ltd

Toward Excellence with Equity: An Emerging Vision for Closing the Achievement Gap

ERIC Educational Resources Information Center

Ferguson, Ronald F.

2007-01-01

For the past 15 years, economist Ronald Ferguson has investigated the myriad factors that combine to create racial disparities in academic performance. Beginning with his analysis of the impact of test scores in predicting racial wage gaps, Ferguson has explored how rates of progress in narrowing gaps have varied over the recent decades, the roles…

K-8 Charter Schools: Closing the Achievement Gap. Innovations in Education

ERIC Educational Resources Information Center

US Department of Education, 2007

2007-01-01

This guide is part of a series produced by the U.S. Department of Education, and it builds on two previous works: "Successful Charter Schools" (ED493615) and "Charter High Schools Closing the Achievement Gap" (ED494482). It profiles seven K-8 charter schools that are making headway in narrowing gaps in achievement. It examines…

Public Perceptions of the Pay Gap

ERIC Educational Resources Information Center

Hill, Catherine; Silva, Elena

2005-01-01

Women have made gains toward closing the gender pay gap during the past two decades. Much of the progress occurred during the 1980s, with smaller gains in the 1990s (Institute for Women's Policy Research 2004). Women's achievements in higher education are partly responsible for narrowing the pay gap in the 1980s and 1990s. As more women earned…

Urban Schools that Have Narrowed the Achievement Gap: Middle School Math Achievement in an Urban Setting

ERIC Educational Resources Information Center

Sagun, Theodore

2010-01-01

The achievement gap is a persistent academic disparity between White and Asian students and ethnic minorities, English Language Learners, and low-income students. The academic disparity exists within the realm of mathematics. Although many factors are cited for contributing to the achievement gap, this study reviews institutional racism, meager…

The Effects of Reading Recovery™ on the American Indian/Non-American Indian Achievement Gap

ERIC Educational Resources Information Center

Collins, Mary L.

2012-01-01

Despite the attention being paid to the achievement gap of minorities, the regulations and laws being enacted, the research being conducted, and the funding made available to narrow the achievement gap, there is evidence that shows it still exists for American Indians. This study examined the effects of Reading Recovery, an early literacy…

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…

Family Formation and Men's and Women's Attainment of Workplace Authority

ERIC Educational Resources Information Center

Bygren, Magnus; Gahler, Michael

2012-01-01

Using Swedish panel data, we assess whether the gender gap in supervisory authority has changed during the period 1968-2000, and investigate to what extent the gap can be attributed to gender-specific consequences of family formation. The results indicate that the gap has narrowed modestly during the period, and that the life-event of parenthood…

Will Public Pre-K Really Close Achievement Gaps? Gaps in Prekindergarten Quality between Students and across States

ERIC Educational Resources Information Center

Valentino, Rachel

2018-01-01

Publicly funded pre-K is often touted as a means to narrow achievement gaps, but this goal is less likely to be achieved if poor and/or minority children do not, at a minimum, attend equal quality pre-K as their non-poor, non-minority peers. In this paper, I find large "quality gaps" in public pre-K between poor, minority students and…

Preparation of the spacer for narrow electrode gap configuration in ionization-based gas sensor

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

Saheed, Mohamed Shuaib Mohamed; Mohamed, Norani Muti; Burhanudin, Zainal Arif

2012-09-26

Carbon nanotubes (CNTs) have started to be developed as the sensing element for ionization-based gas sensors due to the demand for improved sensitivity, selectivity, stability and other sensing properties beyond what can be offered by the conventional ones. Although these limitations have been overcome, the problems still remain with the conventional ionization-based gas sensors in that they are bulky and operating with large breakdown voltage and high temperature. Recent studies have shown that the breakdown voltage can be reduced by using nanostructured electrodes and narrow electrode gap. Nanostructured electrode in the form of aligned CNTs array with evenly distributed nanotipsmore » can enhance the linear electric field significantly. The later is attributed to the shorter conductivity path through narrow electrode gap. The paper presents the study on the design consideration in order to realize ionization based gas sensor using aligned carbon nanotubes array in an optimum sensor configuration with narrow electrode gap. Several deposition techniques were studied to deposit the spacer, the key component that can control the electrode gap. Plasma spray deposition, electron beam deposition and dry oxidation method were employed to obtain minimum film thickness around 32 {mu}m. For plasma spray method, sand blasting process is required in order to produce rough surface for strong bonding of the deposited film onto the surface. Film thickness, typically about 39 {mu}m can be obtained. For the electron beam deposition and dry oxidation, the film thickness is in the range of nanometers and thus unsuitable to produce the spacer. The deposited multilayer film consisting of copper, alumina and ferum on which CNTs array will be grown was found to be removed during the etching process. This is attributed to the high etching rate on the thin film which can be prevented by reducing the rate and having a thicker conductive copper film.« less

Instructional Strategies and Best Practices for Improving the Achievement Gap in Mathematics: An Exploratory Case Study

ERIC Educational Resources Information Center

Lord, Joey

2017-01-01

This qualitative exploratory case study focused on the achievement gap in mathematics that exists in one urban North Carolina middle school and the strategies used by school personnel to narrow this gap. The goal of this research was to determine effective instructional strategies and best practices used to engage students in learning that will…

Instructional Strategies and Best Practices to Narrow the Mathematics Achievement Gaps between African American, Hispanic, and European American Students

ERIC Educational Resources Information Center

Bolden, Felicia Mickles

2012-01-01

A persistent mathematics achievement gap between African American, Hispanic, and European American students at one elementary school was the focus of this investigation. The research questions of this single site case study involved understanding why an achievement gap exists, and to identify the instructional strategies and best practices used to…

Effect of a crystal-melt interface on Taylor-vortex flow

NASA Technical Reports Server (NTRS)

Mcfadden, G. B.; Coriell, S. R.; Murray, B. T.; Glicksman, M. E.; Selleck, M. E.

1990-01-01

The linear stability of circular Couette flow between concentric infinite cylinders is considered for the case that the stationary outer cylinder is a crystal-melt interface rather than a rigid surface. A radial temperature difference is maintained across the liquid gap, and equations for heat transport in the crystal and melt phases are included to extend the ordinary formulation of this problem. The stability of this two-phase system depends on the Prandtl number. For small Prandtl number the linear stability of the two-phase system is given by the classical results for a rigid-walled system. For increasing values of the Prandtl number, convective heat transport becomes significant and the system becomes increasingly less stable. Previous results in a narrow-gap approximation are extended to the case of a finite gap, and both axisymmetric and nonaxisymmetric disturbance modes are considered. The two-phase system becomes less stable as the finite gap tends to the narrow-gap limit. The two-phase system is more stable to nonaxisymmetric modes with azimuthal wavenumber n = 1; the stability of these n = 1 modes is sensitive to the latent heat of fusion.

Daphnis Up Close

NASA Image and Video Library

2017-01-18

The wavemaker moon, Daphnis, is featured in this view, taken as NASA's Cassini spacecraft made one of its ring-grazing passes over the outer edges of Saturn's rings on Jan. 16, 2017. This is the closest view of the small moon obtained yet. Daphnis (5 miles or 8 kilometers across) orbits within the 42-kilometer (26-mile) wide Keeler Gap. Cassini's viewing angle causes the gap to appear narrower than it actually is, due to foreshortening. The little moon's gravity raises waves in the edges of the gap in both the horizontal and vertical directions. Cassini was able to observe the vertical structures in 2009, around the time of Saturn's equinox (see PIA11654). Like a couple of Saturn's other small ring moons, Atlas and Pan, Daphnis appears to have a narrow ridge around its equator and a fairly smooth mantle of material on its surface -- likely an accumulation of fine particles from the rings. A few craters are obvious at this resolution. An additional ridge can be seen further north that runs parallel to the equatorial band. Fine details in the rings are also on display in this image. In particular, a grainy texture is seen in several wide lanes which hints at structures where particles are clumping together. In comparison to the otherwise sharp edges of the Keeler Gap, the wave peak in the gap edge at left has a softened appearance. This is possibly due to the movement of fine ring particles being spread out into the gap following Daphnis' last close approach to that edge on a previous orbit. A faint, narrow tendril of ring material follows just behind Daphnis (to its left). This may have resulted from a moment when Daphnis drew a packet of material out of the ring, and now that packet is spreading itself out. The image was taken in visible (green) light with the Cassini spacecraft narrow-angle camera. The view was acquired at a distance of approximately 17,000 miles (28,000 kilometers) from Daphnis and at a Sun-Daphnis-spacecraft, or phase, angle of 71 degrees. Image scale is 551 feet (168 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA21056

Valuing both critical and creative thinking in clinical practice: narrowing the research-practice gap?

PubMed

Seymour, Beth; Kinn, Sue; Sutherland, Norrie

2003-05-01

Nurturing critical thinking skills in the classroom is considered an important educational activity. It is believed that critical thinking skills are transferable and that they can be applied in practice when appraising, evaluating and implementing research. That more nurses than ever before have been judged academically knowledgeable in research has not guaranteed the transfer of such knowledge to practice. This paper discusses some of the reasons for the failure to narrow the gap between research and practice. In particular we argue that, if nurses are encouraged to develop creative and generative thinking alongside their critical thinking skills, then the art of nursing will have fuller representation in education, research and practice. The successful development of critical thinking skills for academic purposes does not necessarily mean that these skills are used in practice in relation either to research or clinical decision-making. This suggests that the transferability of critical thinking skills is less than straightforward. Indeed, there has been little narrowing of the research-practice gap since students started to learn critical thinking for academic purposes. However, we propose that thinking skills can be encouraged in the context of practice and that regular educational events, such as journal clubs, can contribute to developing critical thinking in the practice environment. The research-practice gap will reduce only if research becomes part of practitioners' ideology, which includes the art and science of nursing. Critical and creative thinking are prerequisites to narrowing the disjuncture between research and practice, and we suggest that educators and practitioners explore structured ways of meeting together to appraise literature as a possible means of making use of their thinking and knowledge in clinical practice.

Optical properties of A Fe 2 As 2 ( A = Ca , Sr, and Ba) single crystals

DOE PAGES

Dai, Y. M.; Akrap, Ana; Bud'ko, S. L.; ...

2016-11-23

The detailed optical properties have been determined for the iron-based materials A Fe 2 As 2 , where A = Ca , Sr, and Ba, for light polarized in the iron-arsenic (a-b) planes over a wide frequency range, above and below the magnetic and structural transitions at T N = 138 , 195, and 172 K, respectively. The real and imaginary parts of the complex conductivity are fit simultaneously using two Drude terms in combination with a series of oscillators. Above T N, the free-carrier response consists of a weak, narrow Drude term, and a strong, broad Drude term, both of which show only a weak temperature dependence. Below T N there is a slight decrease of the plasma frequency but a dramatic drop in the scattering rate for the narrow Drude term, and for the broad Drude term there is a significant decrease in the plasma frequency, while the decrease in the scattering rate, albeit significant, is not as severe. The small values observed for the scattering rates for the narrow Drude term for Tmore » $$\\ll$$ T N may be related to the Dirac conelike dispersion of the electronic bands. Below T N new features emerge in the optical conductivity that are associated with the reconstruction Fermi surface and the gapping of bands at Δ 1 ≃ 45 – 80 meV, and Δ 2 ≃ 110 – 210 meV. In conclusion, the reduction in the spectral weight associated with the free carriers is captured by the gap structure; specifically, the spectral weight from the narrow Drude term appears to be transferred into the low-energy gap feature, while the missing weight from the broad term shifts to the high-energy gap.« less

Conditions and phase shift of fluid resonance in narrow gaps of bottom mounted caissons

NASA Astrophysics Data System (ADS)

Zhu, Da-tong; Wang, Xing-gang; Liu, Qing-jun

2017-12-01

This paper studies the viscid and inviscid fluid resonance in gaps of bottom mounted caissons on the basis of the plane wave hypothesis and full wave model. The theoretical analysis and the numerical results demonstrate that the condition for the appearance of fluid resonance in narrow gaps is kh=(2 n+1)π ( n=0, 1, 2, 3, …), rather than kh= nπ ( n=0, 1, 2, 3, …); the transmission peaks in viscid fluid are related to the resonance peaks in the gaps. k and h stand for the wave number and the gap length. The combination of the plane wave hypothesis or the full wave model with the local viscosity model can accurately determine the heights and the locations of the resonance peaks. The upper bound for the appearance of fluid resonance in gaps is 2 b/ L<1 (2 b, grating constant; L, wave length) and the lower bound is h/ b≤1. The main reason for the phase shift of the resonance peaks is the inductive factors. The number of resonance peaks in the spectrum curve is dependent on the ratio of the gap length to the grating constant. The heights and the positions of the resonance peaks predicted by the present models agree well with the experimental data.

Zero-gap semiconductor to excitonic insulator transition in Ta2NiSe5

PubMed Central

Lu, Y. F.; Kono, H.; Larkin, T. I.; Rost, A. W.; Takayama, T.; Boris, A. V.; Keimer, B.; Takagi, H.

2017-01-01

The excitonic insulator is a long conjectured correlated electron phase of narrow-gap semiconductors and semimetals, driven by weakly screened electron–hole interactions. Having been proposed more than 50 years ago, conclusive experimental evidence for its existence remains elusive. Ta2NiSe5 is a narrow-gap semiconductor with a small one-electron bandgap EG of <50 meV. Below TC=326 K, a putative excitonic insulator is stabilized. Here we report an optical excitation gap Eop ∼0.16 eV below TC comparable to the estimated exciton binding energy EB. Specific heat measurements show the entropy associated with the transition being consistent with a primarily electronic origin. To further explore this physics, we map the TC–EG phase diagram tuning EG via chemical and physical pressure. The dome-like behaviour around EG∼0 combined with our transport, thermodynamic and optical results are fully consistent with an excitonic insulator phase in Ta2NiSe5. PMID:28205553

Cross-disciplinary research in cancer: an opportunity to narrow the knowledge–practice gap

PubMed Central

Urquhart, R.; Grunfeld, E.; Jackson, L.; Sargeant, J.; Porter, G.A.

2013-01-01

Health services researchers have consistently identified a gap between what is identified as “best practice” and what actually happens in clinical care. Despite nearly two decades of a growing evidence-based practice movement, narrowing the knowledge–practice gap continues to be a slow, complex, and poorly understood process. Here, we contend that cross-disciplinary research is increasingly relevant and important to reducing that gap, particularly research that encompasses the notion of transdisciplinarity, wherein multiple academic disciplines and non-academic individuals and groups are integrated into the research process. The assimilation of diverse perspectives, research approaches, and types of knowledge is potentially effective in helping research teams tackle real-world patient care issues, create more practice-based evidence, and translate the results to clinical and community care settings. The goals of this paper are to present and discuss cross-disciplinary approaches to health research and to provide two examples of how engaging in such research may optimize the use of research in cancer care. PMID:24311951

Cross-disciplinary research in cancer: an opportunity to narrow the knowledge-practice gap.

PubMed

Urquhart, R; Grunfeld, E; Jackson, L; Sargeant, J; Porter, G A

2013-12-01

Health services researchers have consistently identified a gap between what is identified as "best practice" and what actually happens in clinical care. Despite nearly two decades of a growing evidence-based practice movement, narrowing the knowledge-practice gap continues to be a slow, complex, and poorly understood process. Here, we contend that cross-disciplinary research is increasingly relevant and important to reducing that gap, particularly research that encompasses the notion of transdisciplinarity, wherein multiple academic disciplines and non-academic individuals and groups are integrated into the research process. The assimilation of diverse perspectives, research approaches, and types of knowledge is potentially effective in helping research teams tackle real-world patient care issues, create more practice-based evidence, and translate the results to clinical and community care settings. The goals of this paper are to present and discuss cross-disciplinary approaches to health research and to provide two examples of how engaging in such research may optimize the use of research in cancer care.

Adding Some Gas Can Completely Change How an Object in a Liquid-Filled Housing Responds to Vibration

NASA Astrophysics Data System (ADS)

Torczynski, J. R.; O'Hern, T. J.; Clausen, J. R.

2015-11-01

Adding a little gas can completely change the motion of an object in a liquid-filled housing during vibration. A common system exhibiting this behavior is a spring-supported piston in a liquid-filled cylinder, where the gaps between them are narrow and depend on the piston position. When gas is absent, the piston's vibrational response is highly overdamped due to forcing viscous liquid through narrow gaps. When a small amount of gas is added, Bjerknes forces cause some of the gas to migrate below the piston. The resulting two gas regions form a pneumatic spring that enables the liquid to move with the piston, with the result that very little liquid is forced through the narrow gaps. This ``Couette mode'' has low damping and thus has a strong resonance near the frequency given by the pneumatic spring constant and the piston mass. At this frequency, the piston response is large, and the nonlinearity from the gap geometry produces a net force on the piston. This ``rectified'' force can be many times the piston's weight and can cause the piston to compress its supporting spring. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Flow regimes of adiabatic gas-liquid two-phase under rolling conditions

NASA Astrophysics Data System (ADS)

Yan, Chaoxing; Yan, Changqi; Sun, Licheng; Xing, Dianchuan; Wang, Yang; Tian, Daogui

2013-07-01

Characteristics of adiabatic air/water two-phase flow regimes under vertical and rolling motion conditions were investigated experimentally. Test sections are two rectangular ducts with the gaps of 1.41 and 10 mm, respectively, and a circular tube with 25 mm diameter. Flow regimes were recorded by a high speed CCD-camera and were identified by examining the video images. The experimental results indicate that the characteristics of flow patterns in 10 mm wide rectangular duct under vertical condition are very similar to those in circular tube, but different from the 1.41 mm wide rectangular duct. Channel size has a significant influence on flow pattern transition, boundary of which in rectangular channels tends asymptotically towards that in the circular tube with increasing the width of narrow side. Flow patterns in rolling channels are similar to each other, nevertheless, the effect of rolling motion on flow pattern transition are significantly various. Due to the remarkable influences of the friction shear stress and surface tension in the narrow gap duct, detailed flow pattern maps of which under vertical and rolling conditions are indistinguishable. While for the circular tube with 25 mm diameter, the transition from bubbly to slug flow occurs at a higher superficial liquid velocity and the churn flow covers more area on the flow regime map as the rolling period decreases.

Career Attainment among Healthcare Executives: Is the Gender Gap Narrowing?

ERIC Educational Resources Information Center

Branin, Joan Julia

2009-01-01

Health care occupations are expected to be among the fastest growing professions in the next ten years. With such incredible growth expected in employment and wages, and with women's participation in the industry remaining strong, are women in the health care industry, particularly those in health care administration, experiencing a narrowing of…

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

Kong, Lingping; Liu, Gang; Gong, Jue

The organic-inorganic hybrid lead trihalide perovskites have been emerging as the most attractive photovoltaic materials. As regulated by Shockley-Queisser theory, a formidable materials science challenge for improvement to the next level requires further band-gap narrowing for broader absorption in solar spectrum, while retaining or even synergistically prolonging the carrier lifetime, a critical factor responsible for attaining the near-band-gap photovoltage. Herein, by applying controllable hydrostatic pressure, we have achieved unprecedented simultaneous enhancement in both band-gap narrowing and carrier-lifetime prolongation (up to 70% to -100% increase) under mild pressures at -0.3 GPa. The pressure-induced modulation on pure hybrid perovskites without introducing anymore » adverse chemical or thermal effect clearly demonstrates the importance of band edges on the photon-electron interaction and maps a pioneering route toward a further increase in their photovoltaic performance.« less

Narrow and Deep Fano Resonances in a Rod and Concentric Square Ring-Disk Nanostructures

PubMed Central

Huo, Yanyan; Jia, Tianqing; Zhang, Yi; Zhao, Hua; Zhang, Shian; Feng, Donghai; Sun, Zhenrong

2013-01-01

Localized surface plasmon resonances (LSPRs) in metallic nanostructures have been studied intensely in the last decade. Fano interference is an important way to decrease the resonance linewidth and enhance the spectral detection resolution, but realizing a Fano lineshape with both a narrow linewidth and high spectral contrast-ratio is still challenging. Here we propose a metallic nanostructure consisting of a concentric square ring-disk (CSRD) nanostructure and an outside nanorod. Fano linewidth and spectral contrast ratio can be actively manipulated by adjusting the gap between the nanorod and CSRD, and by adjusting the gap between the ring and disk in CSRD. When the gap size in CSRD is reduced to 5 nm, the quadrupolar Fano linewidth is of 0.025 eV, with a contrast ratio of 80%, and the figure of merit reaches 15. PMID:24064596

Omnidirectional narrow optical filters for circularly polarized light in a nanocomposite structurally chiral medium.

PubMed

Avendaño, Carlos G; Palomares, Laura O

2018-04-20

We consider the propagation of electromagnetic waves throughout a nanocomposite structurally chiral medium consisting of metallic nanoballs randomly dispersed in a structurally chiral material whose dielectric properties can be represented by a resonant effective uniaxial tensor. It is found that an omnidirectional narrow pass band and two omnidirectional narrow band gaps are created in the blue optical spectrum for right and left circularly polarized light, as well as narrow reflection bands for right circularly polarized light that can be controlled by varying the light incidence angle and the filling fraction of metallic inclusions.

Auger Up-Conversion of Low-Intensity Infrared Light in Engineered Quantum Dots

DOE PAGES

Makarov, Nikolay S.; Lin, Qianglu; Pietryga, Jeffrey M.; ...

2016-11-29

One source of efficiency losses in photovoltaic cells is their transparency toward solar photons with energies below the band gap of the absorbing layer. This loss can be reduced using a process of up-conversion whereby two or more sub-band-gap photons generate a single above-gap exciton. Traditional approaches to up-conversion, such as nonlinear two-photon absorption (2PA) or triplet fusion, suffer from low efficiency at solar light intensities, a narrow absorption bandwidth, nonoptimal absorption energies, and difficulties for implementing in practical devices. We show that these deficiencies can be alleviated using the effect of Auger up-conversion in thick-shell PbSe/CdSe quantum dots. Thismore » process relies on Auger recombination whereby two low-energy, core-based excitons are converted into a single higher-energy, shell-based exciton. When compared to their monocomponent counterparts, the tailored PbSe/CdSe heterostructures feature enhanced absorption cross-sections, a higher efficiency of the “productive” Auger pathway involving re-excitation of a hole, and longer lifetimes of both core- and shell-localized excitons. These features lead to effective up-conversion cross-sections that are more than 6 orders of magnitude higher than for standard nonlinear 2PA, which allows for efficient up-conversion of continuous wave infrared light at intensities as low as a few watts per square centimeter.« less

"Mind the Gap": An Empirical Study of the Gap between Intention and Actual Usage of Corporate E-Learning Programmes in the Financial Industry

ERIC Educational Resources Information Center

Luor, Tainyi; Hu, Changya; Lu, His-Peng

2009-01-01

While numerous previous studies have focused on the use of some corporate e-learning programmes (CELP), little is known about the difference between users' pre-installation reactions to CELP and user's post-installation reactions to CELP. This study narrows the above gap with two investigations into a financial company's CELP. In the…

Stall in Women's Real Wage Growth Slows Progress in Closing the Wage Gap. Briefing Paper.

ERIC Educational Resources Information Center

Hartmann, Heidi; Whittaker, Julie

Since 1979, the wage gap between women and men has narrowed significantly, falling by more than 10 percent overall. The closing of the wage gap has slowed considerably in the 1990's, however, with women's real wages (adjusted for inflation) stagnating in recent year and men's wages continuing to decline. The lack of growth in both women's and…

The Persistent Gap: Understanding Male-Female Salary Differentials amongst Canadian Academic Staff. CAUT Equity Review. Number 5

ERIC Educational Resources Information Center

Canadian Association of University Teachers, 2011

2011-01-01

There has been a long-standing concern amongst policymakers, economists, and trade unions over the persistent earnings gap between men and women in the Canadian labour market. Although this gap has narrowed over time, women's average hourly wages still remain about 16% lower than that earned by men. The reasons for this inequality in male and…

EDUCATIONAL OPPORTUNITIES FOR BOYS AND GIRLS IN THAILAND

PubMed Central

Curran, Sara R.; Chung, Chang Y.; Cadge, Wendy; Varangrat, Anchalee

2016-01-01

Within individual countries, the paths towards increasing educational attainment are not always linear and individuals are not equally affected. Differences between boys’ and girls’ educational attainments are a common expression of this inequality as boys are more often favored for continued schooling. We examine the importance of birth cohort, sibship size, migration, and school accessibility for explaining both the gender gap and its narrowing in secondary schooling in one district in Northeast Thailand between 1984–1994. Birth cohort is a significant explanation for the narrowing of the gender gap. Migration, sibship size, and remote village location are important explanations for limited secondary education opportunities, especially for girls. PMID:27570492

Crossovers from excitons to plasmons in narrow-gap carbon nanotubes

NASA Astrophysics Data System (ADS)

Uryu, Seiji

2018-06-01

Plasmons and excitons, bound states of electrons and holes, are collective charge excitations in solids. In this study, we numerically show that in most metallic carbon nanotubes, which are called narrow-gap carbon nanotubes, excitons cross over to plasmons as the wave vector increases. This indicates that resonance with the excitons changes to that with the plasmons by changing the nanotube length, which can explain the origin of observed peaks in the terahertz or far-infrared region in the optical absorption spectra of metallic carbon nanotubes. In the crossovers from excitons to plasmons, a depolarization effect on the many-body wave functions of the plasmons and excitons is clarified.

Cyclic mechanical loading promotes bacterial penetration along composite restoration marginal gaps

PubMed Central

Khvostenko, D.; Salehi, S.; Naleway, S. E.; Hilton, T. J.; Ferracane, J. L.; Mitchell, J. C.; Kruzic, J. J.

2015-01-01

Objectives Secondary caries is the most common reason for composite restoration replacement and usually forms between dentin and the filling. The objective of this study was to investigate the combined effect of cyclic loading and bacterial exposure on bacterial penetration into gaps at the interface between dentin and resin composite restorative material using a novel bioreactor system and test specimen design. Methods Human molars were machined into 3 mm thick disks with 2 mm deep × 5 mm diameter cavity preparations into which composite restorations were placed. A ∼15-30 micrometer (small) or ∼300 micrometer wide (large) dentin-restoration gap was introduced along half of the interface between the dentin and restoration. Streptococcus mutans UA 159 biofilms were grown on each sample prior to testing in a bioreactor both with and without cyclic loading. Both groups of samples were tested for 2 weeks and post-test biofilm viability was confirmed with a live-dead assay. Samples were fixed, mounted and cross-sectioned to reveal the gaps and observe the depth of bacterial penetration. Results It was shown that for large gap samples the bacteria easily penetrated to the full depth of the gap independent of loading or non-loading conditions. The results for all cyclically loaded small gap samples show a consistently deep bacterial penetration down 100% of the gap while the average penetration depth was only 67% for the non-loaded samples with only two of six samples reaching 100%. Significance A new bioreactor was developed that allows combining cyclic mechanical loading and bacterial exposure of restored teeth for bacterial biofilm and demineralization studies. Cyclic loading was shown to aid bacterial penetration into narrow marginal gaps, which could ultimately promote secondary caries formation. PMID:25900624

The Wage Gap: Briefing Paper #1.

ERIC Educational Resources Information Center

National Committee on Pay Equity, Washington, DC.

Women have made slow, steady progress in the labor market since 1979, but the wage gap has not narrowed significantly. This briefing paper updates a September 1987 paper based on "Male-Female Differences in Work Experience, Occupations, and Earnings: 1984" (Current Population Reports, Household Economic Studies, Series P-70, No. 10, issued in…

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…

School Personnel-Student Racial Congruence and the Achievement Gap

ERIC Educational Resources Information Center

Moore, Allison B.; MacGregor, Cynthia; Cornelius-White, Jeffrey

2017-01-01

Purpose: This paper aims to examine the relationship between student achievement and racial congruence of school personnel and students to help educators and policy makers narrow the achievement gap. Design/methodology/approach: This quasi-experimental, correlational study used publicly available data from 158 elementary schools in the Houston…

Narrowing the Achievement Gap: A Case Study of One Outperforming Urban School Making A Difference

ERIC Educational Resources Information Center

Garner, Dionne M.

2017-01-01

Despite efforts to positively impact educational outcomes for underrepresented youth, the achievement gap persists in the United States. Underrepresented youth are students representing lower socioeconomic, racial, ethnic, or language minority populations that are underrepresented in higher educational attainment relative to their numbers in the…

Racial Wealth Disparities: Is the Gap Closing? Working Paper No. 311.

ERIC Educational Resources Information Center

Gittleman, Maury; Wolff, Edward N.

Most studies of the economic progress of African Americans have focused on income or narrower measures, such as learning, to assess the extent to which any gains relative to other ethnic groups can be attributed to factors such as declining racial discrimination, affirmative action policies, changes in industrial composition, or a narrowing of the…

Women in Academic Science: Experimental Findings from Hiring Studies

ERIC Educational Resources Information Center

Ceci, Stephen J.

2018-01-01

Although women are underrepresented in the most mathematically intensive fields, the gender gap in these fields has narrowed over the past 2 decades. In my E. L. Thorndike address I summarized the temporal trends in sex differences for 8 fields and considered factors that drive both the underrepresentation of women and its recent narrowing. I…

Band gap narrowing in n-type and p-type 3C-, 2H-, 4H-, 6H-SiC, and Si

NASA Astrophysics Data System (ADS)

Persson, C.; Lindefelt, U.; Sernelius, B. E.

1999-10-01

Doping-induced energy shifts of the conduction band minimum and the valence band maximum have been calculated for n-type and p-type 3C-, 2H-, 4H-, 6H-SiC, and Si. The narrowing of the fundamental band gap and of the optical band gap are presented as functions of ionized impurity concentration. The calculations go beyond the common parabolic treatments of the ground state energy dispersion by using energy dispersion and overlap integrals from band structure calculations. The nonparabolic valence band curvatures influence strongly the energy shifts especially in p-type materials. The utilized method is based on a zero-temperature Green's function formalism within the random phase approximation with local field correction according to Hubbard. We have parametrized the shifts of the conduction and the valence bands and made comparisons with recently published results from a semi-empirical model.

Decoration of wide bandgap semiconducting materials for enhancing photoelectrochemical efficiency of PEC systems.

NASA Astrophysics Data System (ADS)

Bakranov, N.; Zhabaikhanov, A.; Kudaibergenov, S.; Ibraev, N.

2018-03-01

The production of photoanodes based on wide-band gap materials such as TiO2 is economically viable because of the low cost of synthesis methods. Contrary to economic aspects, wide-band gap semiconductor materials have a significant disadvantage due to low sensitivity to photons of visible light. To increase the photoactive parameters of the material of the electrodes in the visible range, the methods for decorating nanomasses of titanium dioxide by narrow-gap semiconductors are used. One of the most suitable narrow-gap semiconductor materials are CdS and Fe2O3. Controlled deposition of such materials on wide-gap semiconductors allows to regulate both the diffusion time of charge carriers and the band structure of TiO2/Fe2O3 and TiO2/CdS composites. The dimensions of the structure of the photoelectrode material of the cell have a large influence on the characteristics of the photocatalyst created. Thus, in the hematite structures of nanometre dimension, the rate of recombination of charge carriers fades away in comparison with bulk structures. Reducing the size of CdS structures also positively affects the nature of the photocatalytic reaction.

Vision and spectroscopic sensing for joint tracing in narrow gap laser butt welding

NASA Astrophysics Data System (ADS)

Nilsen, Morgan; Sikström, Fredrik; Christiansson, Anna-Karin; Ancona, Antonio

2017-11-01

The automated laser beam butt welding process is sensitive to positioning the laser beam with respect to the joint because a small offset may result in detrimental lack of sidewall fusion. This problem is even more pronounced in case of narrow gap butt welding, where most of the commercial automatic joint tracing systems fail to detect the exact position and size of the gap. In this work, a dual vision and spectroscopic sensing approach is proposed to trace narrow gap butt joints during laser welding. The system consists of a camera with suitable illumination and matched optical filters and a fast miniature spectrometer. An image processing algorithm of the camera recordings has been developed in order to estimate the laser spot position relative to the joint position. The spectral emissions from the laser induced plasma plume have been acquired by the spectrometer, and based on the measurements of the intensities of selected lines of the spectrum, the electron temperature signal has been calculated and correlated to variations of process conditions. The individual performances of these two systems have been experimentally investigated and evaluated offline by data from several welding experiments, where artificial abrupt as well as gradual deviations of the laser beam out of the joint were produced. Results indicate that a combination of the information provided by the vision and spectroscopic systems is beneficial for development of a hybrid sensing system for joint tracing.

Shear Stress induced Stretching of Red Blood Cells by Oscillating Bubbles within a Narrow Gap

NASA Astrophysics Data System (ADS)

Li, Fenfang; Mohammadzadeh, Milad; Ohl, Claus-Dieter; Claus-Dieter Ohl Team

2013-11-01

The flow pattern, especially the boundary layer caused by the expanding/contracting bubble in a narrow gap (15 μm) and the resultant stretching of red blood cells is investigated in this work. High speed recordings show that a red blood cell (biconcave shape, thickness of 1-2 μm) can be elongated to five times its original length by a laser-induced cavitation bubble within the narrow gap. However, flexible cancer cells in suspension (RKO, spherical shape, diameter of 10-15 μm) are hardly elongated under the same experimental condition. We hypothesize that the shear stress at the boundary layer is crucial for this elongation to occur. Therefore, in order to resolve the related fluid dynamics, we conducted numerical simulations using the finite element method (Fluent). The rapidly expanding/contracting vapor bubble is successfully modeled by employing viscosity and surface tension. The transient pressure inside the bubble and the velocity profile of the flow is obtained. We observe strong shear near the upper and lower boundary during the bubble oscillation. The flow fields are compared with analytical solutions to transient and pulsating flows in 2D. In the experiment the red blood cells sit within the lower boundary layer, thus are probably elongated by this strong shear flow. In contrast, the spherical cancer cells are of comparable size to the gap height so that they are lesser affected by this boundary layer flow.

H-tailored surface conductivity in narrow band gap In(AsN)

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

Velichko, A. V., E-mail: amalia.patane@nottingham.ac.uk, E-mail: anton.velychko@nottingham.ac.uk; Patanè, A., E-mail: amalia.patane@nottingham.ac.uk, E-mail: anton.velychko@nottingham.ac.uk; Makarovsky, O.

2015-01-12

We show that the n-type conductivity of the narrow band gap In(AsN) alloy can be increased within a thin (∼100 nm) channel below the surface by the controlled incorporation of H-atoms. This channel has a large electron sheet density of ∼10{sup 18 }m{sup −2} and a high electron mobility (μ > 0.1 m{sup 2}V{sup −1}s{sup −1} at low and room temperature). For a fixed dose of impinging H-atoms, its width decreases with the increase in concentration of N-atoms that act as H-traps thus forming N-H donor complexes near the surface.

FAST OPENING SWITCH

DOEpatents

Bender, M.; Bennett, F.K.; Kuckes, A.F.

1963-09-17

A fast-acting electric switch is described for rapidly opening a circuit carrying large amounts of electrical power. A thin, conducting foil bridges a gap in this circuit and means are provided for producing a magnetic field and eddy currents in the foil, whereby the foil is rapidly broken to open the circuit across the gap. Advantageously the foil has a hole forming two narrow portions in the foil and the means producing the magnetic field and eddy currents comprises an annular coil having its annulus coaxial with the hole in the foil and turns adjacent the narrow portions of the foil. An electrical current flows through the coil to produce the magnetic field and eddy currents in the foil. (AEC)

Green digital signage using nanoparticle embedded narrow-gap field sequential TN-LCDs

NASA Astrophysics Data System (ADS)

Kobayashi, Shunsuke; Shiraishi, Yukihide; Sawai, Hiroya; Toshima, Naoki; Okita, Masaya; Takeuchi, Kiyofumi; Takatsu, Haruyoshi

2012-03-01

We have fabricated field sequential color (FSC)-LCDs using cells and modules of narrow-gap TN-LCDs with and without doping the nanoparticles of PCyD-ZrO2 and AF-SiO2. It is shown that the FSC-LCD exhibits a high optical efficiency of OE=4.5 that is defined as OE=[Luminance]/[W/m2]=(cd/W). This figure may provide us a good reference or to clear the Energy Star Program Version 5-3 that issues a guideline: LCD with 50 inch on the diagonal consumes the energy of 108W. Through this research it is claimed that our FSC=LCD may be a novel green digital signage.

Structural phase transition, narrow band gap, and room-temperature ferromagnetism in [KNbO{sub 3}]{sub 1−x}[BaNi{sub 1/2}Nb{sub 1/2}O{sub 3−δ}]{sub x} ferroelectrics

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

Zhou, Wenliang; Yang, Pingxiong, E-mail: pxyang@ee.ecnu.edu.cn; Chu, Junhao

2014-09-15

Structural phase transition, narrow band gap (E{sub g}), and room-temperature ferromagnetism (RTFM) have been observed in the [KNbO{sub 3}]{sub 1−x}[BaNi{sub 1/2}Nb{sub 1/2}O{sub 3−δ}]{sub x} (KBNNO) ceramics. All the samples have single phase perovskite structure, but exhibit a gradual transition behaviour from the orthorhombic to a cubic structure with the increase of x. Raman spectroscopy analysis not only corroborates this doping-induced change in normal structure but also shows the local crystal symmetry for x ≥ 0.1 compositions to deviate from the idealized cubic perovskite structure. A possible mechanism for the observed specific changes in lattice structure is discussed. Moreover, it ismore » noted that KBNNO with compositions x = 0.1–0.3 have quite narrow E{sub g} of below 1.5 eV, much smaller than the 3.2 eV band gap of parent KNbO{sub 3} (KNO), which is due to the increasing Ni 3d electronic states within the gap of KNO. Furthermore, the KBNNO materials present RTFM near a tetragonal to cubic phase boundary. With increasing x from 0 to 0.3, the magnetism of the samples develops from diamagnetism to ferromagnetism and paramagnetism, originating from the ferromagnetic–antiferromagnetic competition. These results are helpful in the deeper understanding of phase transitions, band gap tunability, and magnetism variations in perovskite oxides and show the potential role, such materials can play, in perovskite solar cells and multiferroic applications.« less

Narrowing the Achievement Gap: A Review of Research, Policies, and Issues. Report.

ERIC Educational Resources Information Center

Hertert, Linda; Teague, Jackie

Student achievement tests consistently show that certain groups of children score far below children in other groups. The data document a strong association between poverty and students' academic success. The achievement gap begins early in children's lives as the result of physical, social, and emotional deprivations. California is attempting to…

The ABC of Gender Equality in Education: Aptitude, Behaviour, Confidence

ERIC Educational Resources Information Center

OECD Publishing, 2015

2015-01-01

Over the past century, the Organisation for Economic Cooperation and Development (OECD) countries have made significant progress in narrowing or closing long-standing gender gaps in many areas of education and employment, including educational attainment, pay and labour market participation. But new gender gaps in education are opening. Young men…

Closing the Math Achievement Gap: Institutions Find Success with MyMathLab

ERIC Educational Resources Information Center

Stewart, Pearl

2012-01-01

Institutions find success with Pearson Education's MyMathLab. The Department of Mathematical Sciences at the University of Memphis (UM) reported a narrowing of the achievement gap between Black and White students. According to the study conducted by UM professors and titled "The Effectiveness of Blended Instruction in Postsecondary General…

Minding the Gap: Investing in a Skilled Manufacturing Workforce

ERIC Educational Resources Information Center

Richard, Alan

2015-01-01

Advanced manufacturing is growing and thriving in the United States. Companies are in great need of reliable employees who can communicate well, effectively make decisions, and are interested in long-term careers with opportunity for advancement. Employers have identified a need for a more robust talent pipeline to narrow America's skills gap--a…

Book Probes Scoring Gaps Tied to Race

ERIC Educational Resources Information Center

Viadero, Debra

2009-01-01

A recent book assembles a collection of studies on one of the great mysteries of contemporary American education: Why did national progress in narrowing the achievement gap separating African-American and white students stall from the late 1980s until 2004? "Steady Gains and Stalled Progress," published by the Russell Sage Foundation of New York…

Workaholism: Bridging the Gap between Workplace, Sociocultural, and Family Research.

ERIC Educational Resources Information Center

Robinson, Bryan E.

2000-01-01

Article attempts to narrow the gap between studies of workaholism and human relations/organizational development, and workaholism and cross-cultural research and family counseling. Counselors are encouraged to be aware of implications of workaholism for clients, including burnout and family disintegration, and screen for it just as they would for…

Can Within-Race Achievement Comparisons Help Narrow Between-Race Achievement Gaps?

ERIC Educational Resources Information Center

Duke, Daniel L.

2017-01-01

Reports on the low achievement of African American students tend to focus on Black-White achievement gaps. This study draws from official reports that also consider within-race achievement differences. An argument is presented that within-race comparisons are likely to reveal important causal factors that may go unnoticed when between-race…

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.

Zero-gap semiconductor to excitonic insulator transition in Ta2NiSe5.

PubMed

Lu, Y F; Kono, H; Larkin, T I; Rost, A W; Takayama, T; Boris, A V; Keimer, B; Takagi, H

2017-02-16

The excitonic insulator is a long conjectured correlated electron phase of narrow-gap semiconductors and semimetals, driven by weakly screened electron-hole interactions. Having been proposed more than 50 years ago, conclusive experimental evidence for its existence remains elusive. Ta 2 NiSe 5 is a narrow-gap semiconductor with a small one-electron bandgap E G of <50 meV. Below T C =326 K, a putative excitonic insulator is stabilized. Here we report an optical excitation gap E op ∼0.16 eV below T C comparable to the estimated exciton binding energy E B . Specific heat measurements show the entropy associated with the transition being consistent with a primarily electronic origin. To further explore this physics, we map the T C -E G phase diagram tuning E G via chemical and physical pressure. The dome-like behaviour around E G ∼0 combined with our transport, thermodynamic and optical results are fully consistent with an excitonic insulator phase in Ta 2 NiSe 5 .

Narrowing the Achievement Gap: Factors That Support English Learner and Hispanic Student Academic Achievement in an Urban Intermediate School

ERIC Educational Resources Information Center

Flores, Patricia Arleen

2010-01-01

A persistent and pervasive disparity in academic achievement exists between ethnic minority and English Learner students and their White and Asian peers. This qualitative single-case study of a high-poverty, high-performing middle school focused on the cultural norms, practices, and programs that were perceived to be contributing to narrowing the…

Are Early Childhood Disparities Narrowing? The Changing Nature of Early Childhood and Its Link to Narrowing School-Entry Achievement Gaps

ERIC Educational Resources Information Center

Bassok, Daphna; Finch, Jenna; Lee, RaeHyuck; Reardon, Sean F.; Waldfogel, Jane

2016-01-01

To date, no studies have documented how much early childhood experiences have changed over time. In the current study, researchers use two large, nationally representative datasets of kindergarten entrants to document the following: (1) How have children's early childhood experiences changed between 1998 and 2010?; (2) To what extent have…

Birth Cohort and the Black-White Achievement Gap: The Roles of Access and Health Soon After Birth. WP2008-20

ERIC Educational Resources Information Center

Chay, Kenneth Y.; Guryan, Jonathan; Mazumder, Bhashkar

2009-01-01

One literature documents a significant, black-white gap in average test scores, while another finds a substantial narrowing of the gap during the 1980's, and stagnation in convergence after. We use two data sources--the Long Term Trends NAEP and AFQT scores for the universe of applicants to the U.S. military between 1976 and 1991--to show: (1) the…

Birth Cohort and the Black-White Achievement Gap: The Roles of Access and Health Soon after Birth. NBER Working Paper No. 15078

ERIC Educational Resources Information Center

Chay, Kenneth Y.; Guryan, Jonathan; Bhashkar, Mazumder

2009-01-01

One literature documents a significant, black-white gap in average test scores, while another finds a substantial narrowing of the gap during the 1980's, and stagnation in convergence after. We use two data sources -- the Long Term Trends NAEP and AFQT scores for the universe of applicants to the U.S. military between 1976 and 1991 -- to show: 1)…

Minding and mending the gap: Social psychological interventions to reduce educational disparities.

PubMed

Spitzer, Brian; Aronson, Joshua

2015-03-01

Achievement gaps continue to garner a great deal of attention both in academic and in popular circles. Many students continue to struggle despite broad educational reforms aimed at narrowing these gaps in learning and performance. In this article, we review a number of social psychological interventions that show promise in reducing gaps in achievement, not by addressing structural barriers to achievement, but by helping students cope with threats to their identity that impair intellectual functioning and motivation. For example, interventions involving meditation, role models, emotional reappraisal, growth mindsets, imagining possible selves, self-affirmations, belongingness and cooperative learning have been shown to ameliorate threats to identity and raise achievement. We describe and evaluate these social psychological interventions. Many achievement gaps involve a psychological predicament: a threat to one's social identity or to one's sense of belonging. Students' implicit theories - how they mind the gap - can act as barriers to their success. By helping students cope with these threats, these theory-based interventions represent a genuine advance in the way schools may reduce gaps in achievement. These interventions show how students' educational success depends partly on fluid aspects of context - how tasks are framed, who else is in the room, or what they believe about intelligence. Because of this fluidity, these interventions may not work in all settings. Achievement gaps are ultimately caused by a variety of factors, both objective and subjective that produce inequality. The research reviewed here suggests that even without changes in objective barriers to success, brief psychological interventions can narrow what many see as intractable gaps in academic achievement. © 2015 The British Psychological Society.

Gap analysis: synergies and opportunities for effective nursing leadership.

PubMed

Davis-Ajami, Mary Lynn; Costa, Linda; Kulik, Susan

2014-01-01

Gap analysis encompasses a comprehensive process to identify, understand, address, and bridge gaps in service delivery and nursing practice. onducting gap analysis provides structure to information gathering and the process of finding sustainable solutions to important deficiencies. Nursing leaders need to recognize, measure, monitor, and execute on feasible actionable solutions to help organizations make adjustments to address gaps between what is desired and the actual real-world conditions contributing to the quality chasm in health care. Gap analysis represents a functional and comprehensive tool to address organizational deficiencies. Using gap analysis proactively helps organizations map out and sustain corrective efforts to close the quality chasm. Gaining facility in gap analysis should help the nursing profession's contribution to narrowing the quality chasm.

First-principles study of Mn-S codoped anatase TiO2

NASA Astrophysics Data System (ADS)

Li, Senlin; Huang, Jinliang; Ning, Xiangmei; Chen, Yongcha; Shi, Qingkui

2018-04-01

In this work, the CASTEP program in Materials Studio 2017 software package was applied to calculate the electronic structures and optical properties of pure anatase TiO2, S-doped, Mn-doped and Mn-S co-doped anatase TiO2 by GGA + U methods based on the density function theory (DFT). The results indicate that the lattice is distorted and the lattice constant is reduce due to doping. The doping also introduces impurity energy levels into the forbidden band. After substitution of Mn for Ti atom, band gap narrowing of anatase TiO2 is caused by the impurity energy levels appearance in the near Fermi surface, which are contributed by Mn-3d orbital, Ti-3d orbital and O-2p orbital hybridization. After substitution of S for O atom, band gap narrowing is creited with the shallow accepter level under the conduction hand of S-3p orbital. The Mn-S co-doped anatase TiO2 could be a potential candidate for a photocatalyst because of tis enhanced absorption ability of visible light. The results can well explain the immanent cause of a band gap narrowing as well as a red shift in the spectrum for doped anatase TiO2.

Characteristics of Extra Narrow Gap Weld of HSLA Steel Welded by Single-Seam per Layer Pulse Current GMA Weld Deposition

NASA Astrophysics Data System (ADS)

Agrawal, B. P.; Ghosh, P. K.

2017-03-01

Butt weld joints are produced using pulse current gas metal arc welding process by employing the technique of centrally laid multi-pass single-seam per layer weld deposition in extra narrow groove of thick HSLA steel plates. The weld joints are prepared by using different combination of pulse parameters. The selection of parameter of pulse current gas metal arc welding is done considering a summarized influence of simultaneously interacting pulse parameters defined by a dimensionless hypothetical factor ϕ. The effect of diverse pulse parameters on the characteristics of weld has been studied. Weld joint is also prepared by using commonly used multi-pass multi-seam per layer weld deposition in conventional groove. The extra narrow gap weld joints have been found much superior to the weld joint prepared by multi-pass multi-seam per layer deposition in conventional groove with respect to its metallurgical characteristics and mechanical properties.

Two-phase Hele-Shaw flow with a moving contact line

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

Weinstein, S.J.; Ungar, L.H.; Dussan, E.B.

1988-01-01

An asymptotic analysis is presented for Hele-Shaw viscous fingering with a moving contact line at flow rates. As in problems where a thin film is present instead of a contact line, the narrow gap limit is nonuniform, and interfacial boundary conditions valid for the Hele-Shaw equations must be determined in order to predict the flow field and interface shape. Many well-posed boundary-value problems can be identified, each corresponding to a different flow regime characterized by the relative sizes of the capillary number (dimensionless velocity) and the dimensionless gap width. These problems incorporate terms corresponding to the gapwise component of themore » interfacial curvature (the curvature in the cross-sectional view of the Hele-Shaw cell) and spanwise curvature (seen in the top view of the cell) in different ways. Nonunique interface solutions typically arise as in the analogous thin film problems. The relationships between the curvature terms, the spectra of allowable solutions, and the implications for stability are discussed.« less

Media use and HIV/AIDS knowledge: a knowledge gap perspective.

PubMed

Bekalu, Mesfin Awoke; Eggermont, Steven

2014-12-01

Despite the widespread utilization of the mass media in HIV/AIDS prevention, little is known about the knowledge gap that results from disparities in mass media use. This study examined the relationship between HIV/AIDS-related mass media use and HIV/AIDS-related knowledge among urban and rural residents of northwestern Ethiopia. A hierarchical regression analysis indicated that HIV/AIDS-related mass media use has both sequestering and mainstreaming effects in certain segments of the study population, although it was not a significant predictor of HIV/AIDS-related knowledge in the total population. The knowledge gaps between individuals with high and low education and between individuals who experience high and low levels of interpersonal communication about HIV/AIDS narrowed as HIV/AIDS-related media use increased, but the gap between urban and rural residents widened. The widening gap could be explained by differences in perceptions of information salience and several theoretical assumptions. Current mass media information campaigns, which are often prepared and broadcast from urban centers, may not only fail to improve the HIV/AIDS knowledge of the rural populace but also put rural populations at a disadvantage relative to their urban counterparts. Communication interventions informed by socioecological models might be helpful to redress and/or narrow the widening knowledge gap between urban and rural residents. © The Author (2013). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Aerodynamic and acoustic effects of ventricular gap.

PubMed

Alipour, Fariborz; Karnell, Michael

2014-03-01

Supraglottic compression is frequently observed in individuals with dysphonia. It is commonly interpreted as an indication of excessive circumlaryngeal muscular tension and ventricular medialization. The purpose of this study was to describe the aerodynamic and acoustic impact of varying ventricular medialization in a canine model. Subglottal air pressure, glottal airflow, electroglottograph, acoustic signals, and high-speed video images were recorded in seven excised canine larynges mounted in vitro for laryngeal vibratory experimentation. The degree of gap between the ventricular folds was adjusted and measured using sutures and weights. Data were recorded during phonation when the ventricular gap was narrow, neutral, and large. Glottal resistance was estimated by measures of subglottal pressure and glottal flow. Glottal resistance increased systematically as ventricular gap became smaller. Wide ventricular gaps were associated with increases in fundamental frequency and decreases in glottal resistance. Sound pressure level did not appear to be impacted by the adjustments in ventricular gap used in this research. Increases in supraglottic compression and associated reduced ventricular width may be observed in a variety of disorders that affect voice quality. Ventricular compression may interact with true vocal fold posture and vibration resulting in predictable changes in aerodynamic, physiological, acoustic, and perceptual measures of phonation. The data from this report supports the theory that narrow ventricular gaps may be associated with disordered phonation. In vitro and in vivo human data are needed to further test this association. Copyright © 2014 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

The NRSC and the FCC: Working To Change Policy and Procedure To Narrow the Distance between AM and FM.

ERIC Educational Resources Information Center

Huff, W. A. Kelly

In the mid-1980s, the National Association of Broadcasters (NAB) reformed the National Radio Systems Committee (NRSC) as a liaison between receiver manufacturers and amplitude modulation (AM) broadcasters to promote unity in upgrading AM transmission and reception, and to aid AM in narrowing the sound quality gap with frequency modulation (FM). In…

Women's Entry into Management: Trends in Earnings, Authority, and Valued among Salaried Managers.

ERIC Educational Resources Information Center

Jacobs, Jerry A.

1992-01-01

Earnings and authority differentials between male and female managers are analyzed with data from three sources for the period between 1970 and 1988. Results indicate that the sex gap in earnings among managers narrowed during this period, whereas the gap in authority remained constant. The implication of these results for theories of internal…

Jumpstarting Jill: Strategies to Nurture Talented Girls in Your Science Classroom

ERIC Educational Resources Information Center

Heilbronner, Nancy N.

2008-01-01

Women are making progress in many areas of science, but a gender gap still remains, especially in physics, computer science, and engineering, and at advanced levels of academic and career achievement. Today's teachers can help narrow this gap by instilling a love for science in their female students and by helping them to understand and develop…

Addressing Excellence Gaps in K-12 Education. Position Statement

ERIC Educational Resources Information Center

National Association for Gifted Children, 2015

2015-01-01

Since the passage of the No Child Left Behind Act in 2001, a major objective of federal and state education policy has been to narrow K-12 achievement gaps. This position statement notes that the available data suggest that the singular focus on the most struggling learners has resulted in meaningful progress in closing minimum-competency…

The Role of the Superintendent in Closing the Achievement Gap in Diverse Small School Districts

ERIC Educational Resources Information Center

Wright, Howell, Jr.; Harris, Sandra

2010-01-01

The purpose of this qualitative, narrative study was to investigate the role of the superintendent in leading the district to be more culturally proficient, resulting in the narrowing of the achievement gap in culturally diverse small districts. Eight superintendents of small school districts were purposefully selected based on their district size…

Close the Gap: A Multiple Case Study about the Decision-Making Process of Administrators in Ohio Districts

ERIC Educational Resources Information Center

Guthrie, Tammy Reutzel

2017-01-01

Research has identified evidenced-based practices and programs that are successful for increasing the learning outcomes of students with disabilities which in turn helps narrow the achievement gap between the student subgroup and non-disabled peers. Employing the identified practices has produced inconsistent results and led to a closer…

A narrower gap of grazing intensity. Reply to Fetzel et al. 2017. Seasonality constrains to livestock grazing intensity

USDA-ARS?s Scientific Manuscript database

Fetzel et al. (2017) globally mapped the gap between observed and potential grazing intensity (GI): the ratio between consumption by livestock and ANPP. Fetzel et al. (2017) estimated grazing land, forage production and livestock demand at a half-degree resolution. They mapped GI below 15% for most ...

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…

Judging Student Achievement: Why Getting the Right Data Matters. An MPR/NCEA Policy Brief

ERIC Educational Resources Information Center

Anderson, Sharon; Fowler, Donna; Klein, Steve

2005-01-01

States are engaged in serious efforts to raise student achievement, paying particular attention to narrowing the achievement gap between high- and low-performing students that has persisted in public schools for decades. The achievement gap is particularly troubling because, all too often, those at low achievement levels are minority, special…

Fatigue crack growth of 316NG austenitic stainless steel welds at 325 °C

NASA Astrophysics Data System (ADS)

Li, Y. F.; Xiao, J.; Chen, Y.; Zhou, J.; Qiu, S. Y.; Xu, Q.

2018-02-01

316NG austenitic stainless steel is a commonly-used material for primary coolant pipes of pressurized water reactor systems. These pipes are usually joined together by automated narrow gap welding process. In this study, welds were prepared by narrow gap welding on 316NG austenitic stainless steel pipes, and its microstructure of the welds was characterized. Then, fatigue crack growth tests were conducted at 325 °C. Precipitates enriched with Mn and Si were found in the fusion zone. The fatigue crack path was out of plane and secondary cracks initiated from the precipitate/matrix interface. A moderate acceleration of crack growth was also observed at 325°Cair and water (DO = ∼10 ppb) with f = 2 Hz.

Gender equity & human development.

PubMed

Vepa, Swarna S

2007-10-01

The welfare of both women and men constitutes the human welfare. At the turn of the century amidst the glory of unprecedented growth in national income, India is experiencing the spread of rural distress. It is mainly due to the collapse of agricultural economy. Structural adjustments and competition from large-scale enterprises result in loss of rural livelihoods. Poor delivery of public services and safety nets, deepen the distress. The adverse impact is more on women than on men. This review examines the adverse impact of the events in terms of endowments, livelihood opportunities and nutritional outcomes on women in detail with the help of chosen indicators at two time-periods roughly representing mid nineties and early 2000. The gender equality index computed and the major indicators of welfare show that the gender gap is increasing in many aspects. All the aspects of livelihoods, such as literacy, unemployment and wages now have larger gender gaps than before. Survival indicators such as juvenile sex ratio, infant mortality, child labour have deteriorated for women, compared to men, though there has been a narrowing of gender gaps in life expectancy and literacy. The overall gender gap has widened due to larger gaps in some indicators, which are not compensated by the smaller narrowing in other indicators both in the rural and urban context.

High-Performance Polymer Solar Cell with Single Active Material of Fully Conjugated Block Copolymer Composed of Wide-Band gap Donor and Narrow-Band gap Acceptor Blocks.

PubMed

Lee, Ji Hyung; Park, Chang Geun; Kim, Aesun; Kim, Hyung Jong; Kim, Youngseo; Park, Sungnam; Cho, Min Ju; Choi, Dong Hoon

2018-06-06

We synthesized a novel fully conjugated block copolymer, P3, in which a wide-band gap donor block (P1) was connected to a narrow-band gap acceptor block (P2). As P3 contains P1 block with a wide bandgap and P2 block with a narrow bandgap, it exhibits a very wide complementary absorption. Transient photoluminescence measurement using P3 dilute solution demonstrated intramolecular charge transfer between the P1 block and the P2 block, which was not observed in a P1/P2 blend solution. A P3 thin film showed complete PL quenching because the photoinduced inter-/intramolecular charge transfer states were effectively formed. This phenomenon can play an important role in the photovoltaic properties of P3-based polymer solar cells. A single active material polymer solar cell (SAMPSC) fabricated from P3 alone exhibited a high power conversion efficiency (PCE) of 3.87% with a high open-circuit voltage of 0.93 V and a short-circuit current of 8.26 mA/cm 2 , demonstrating a much better performance than a binary P1-/P2-based polymer solar cell (PCE = 1.14%). This result facilitates the possible improvement of the photovoltaic performance of SAMPSCs by inducing favorable nanophase segregation between p- and n blocks. In addition, owing to the high morphological stability of the block copolymer, excellent shelf-life was observed in a P3-based SAMPSC compared with a P1/P2-based PSC.

A Low-Energy-Gap Thienochrysenocarbazole Dye for Highly Efficient Mesoscopic Titania Solar Cells: Understanding the Excited State and Charge Carrier Dynamics.

PubMed

Wang, Junting; Xie, Xinrui; Weng, Guorong; Yuan, Yi; Zhang, Jing; Wang, Peng

2018-05-09

Maintaining both a high external quantum efficiency and a large open-circuit photovoltage of dye-sensitized solar cells (DSSCs) is a crucial challenge in the process of developing narrow-energy-gap dyes for the capture of infrared solar photons. Herein, we report two donor-acceptor organic dyes, C294 and C295, with a polycyclic heteroaromatic unit, 6,11-dihydrothieno[3',2':8,9]chryseno[10,11,12,1-bcdefg]carbazole (TCC), as the central module of the electron donor, and ethylbenzothiadiazole-benzioc acid as the electron acceptor. The interfacial charge recombination was successfully mitigated by introducing an additional branched aliphatic chain in C295. Furthermore, the O⋅⋅⋅S nonbonding interaction between the oxygen atom of the alkoxy group and the sulfur atom of the thiophene in C295 controlled the conformation of C295, resulting in a narrow energy-gap. Time-resolved spectroscopic measurements on C294 and the model dye C272 indicated that the elevation of the HOMO energy level decreased the kinetics and yield of hole injection owing to a reduction in the driving force and that the shortened excited-state lifetime caused by the narrowing of the energy gap was unfavorable for electron injection. By fine tuning the composition of the electrolyte, C294 and C295 eventually achieved high power conversion efficiencies of 11.5 % and 12.4 %, respectively, under full sunlight of air mass 1.5 global conditions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Observations and predictability of gap winds in a steep, narrow, fire-prone canyon in central Idaho, USA

NASA Astrophysics Data System (ADS)

Wagenbrenner, N. S.; Forthofer, J.; Gibson, C.; Lamb, B. K.

2017-12-01

Frequent strong gap winds were measured in a deep, steep, wildfire-prone river canyon of central Idaho, USA during July-September 2013. Analysis of archived surface pressure data indicate that the gap wind events were driven by regional scale surface pressure gradients. The events always occurred between 0400 and 1200 LT and typically lasted 3-4 hours. The timing makes these events particularly hazardous for wildland firefighting applications since the morning is typically a period of reduced fire activity and unsuspecting firefighters could be easily endangered by the onset of strong downcanyon winds. The gap wind events were not explicitly forecast by operational numerical weather prediction (NWP) models due to the small spatial scale of the canyon ( 1-2 km wide) compared to the horizontal resolution of operational NWP models (3 km or greater). Custom WRF simulations initialized with NARR data were run at 1 km horizontal resolution to assess whether higher resolution NWP could accurately simulate the observed gap winds. Here, we show that the 1 km WRF simulations captured many of the observed gap wind events, although the strength of the events was underpredicted. We also present evidence from these WRF simulations which suggests that the Salmon River Canyon is near the threshold of WRF-resolvable terrain features when the standard WRF coordinate system and discretization schemes are used. Finally, we show that the strength of the gap wind events can be predicted reasonably well as a function of the surface pressure gradient across the gap, which could be useful in the absence of high-resolution NWP. These are important findings for wildland firefighting applications in narrow gaps where routine forecasts may not provide warning for wind effects induced by high-resolution terrain features.

Gender equality and violent behavior: how neighborhood gender equality influences the gender gap in violence.

PubMed

Lei, Man-Kit; Simons, Ronald L; Simons, Leslie Gordon; Edmond, Mary Bond

2014-01-01

Using a sample of 703 African American adolescents from the Family and Community Health Study (FACHS) along with census data from the year 2000, we examine the association between neighborhood-level gender equality and violence. We find that boys' and girls' violent behavior is unevenly distributed across neighborhood contexts. In particular, gender differences in violent behavior are less pronounced in gender-equalitarian neighborhoods compared to those characterized by gender inequality. We also find that the gender gap narrows in gender-equalitarian neighborhoods because boys' rates of violence decrease whereas girls' rates remain relatively low across neighborhoods. This is in stark contrast to the pessimistic predictions of theorists who argue that the narrowing of the gender gap in equalitarian settings is the result of an increase in girls' violence. In addition, the relationship between neighborhood gender equality and violence is mediated by a specific articulation of masculinity characterized by toughness. Our results provide evidence for the use of gender-specific neighborhood prevention programs.

Gender Equality and Violent Behavior: How Neighborhood Gender Equality Influences the Gender Gap in Violence

PubMed Central

Lei, Man-Kit; Simons, Ronald L.; Simons, Leslie Gordon; Edmond, Mary Bond

2014-01-01

Using a sample of 703 African American adolescents from the Family and Community Health Study (FACHS) along with census data from the year 2000, we examine the association between neighborhood-level gender equality and violence. We find that boys’ and girls’ violent behavior is unevenly distributed across neighborhood contexts. In particular, gender differences in violent behavior are less pronounced in gender-equalitarian neighborhoods compared to those characterized by gender inequality. We also find that the gender gap narrows in gender-equalitarian neighborhoods because boys’ rates of violence decrease whereas girls’ rates remain relatively low across neighborhoods. This is in stark contrast to the pessimistic predictions of theorists who argue that the narrowing of the gender gap in equalitarian settings is the result of an increase in girls’ violence. In addition, the relationship between neighborhood gender equality and violence is mediated by a specific articulation of masculinity characterized by toughness. Our results provide evidence for the use of gender-specific neighborhood prevention programs. PMID:24672996

Adhesive micro-line periodicity determines guidance of axonal outgrowth†

PubMed Central

Huang, Yu; Fothergill, Thomas; Lumbard, Derek C.; Dent, Erik W.; Williams, Justin C.

2014-01-01

Adhesive micro-lines of various sub-cellular geometries were created using a non-traditional micro stamping technique. This technique employed the use of commercially available diffraction gratings as the molds for the micro stamps, a method which is quick and inexpensive, and which could easily be adopted as a patterning tool in a variety of research efforts. The atypical saw-tooth profile of the micro stamps enabled a unique degree of control and flexibility over patterned line and gap widths. Cortical neurons cultured on patterned poly-lysine micro-lines on PDMS exhibit a startling transition in axonal guidance: From the expected parallel guidance to an unexpected perpendicular guidance that becomes dominant as patterned lines and gaps become sufficiently narrow. This transition is most obvious when the lines are narrow relative to gaps, while the periodicity of the pattern is reduced. Axons growing perpendicular to micro-lines exhibited ‘vinculated’ growth, a unique morphological phenotype consisting of periodic orthogonal extensions along the axon. PMID:23250489

Wave propagation in axially moving periodic strings

NASA Astrophysics Data System (ADS)

Sorokin, Vladislav S.; Thomsen, Jon Juel

2017-04-01

The paper deals with analytically studying transverse waves propagation in an axially moving string with periodically modulated cross section. The structure effectively models various relevant technological systems, e.g. belts, thread lines, band saws, etc., and, in particular, roller chain drives for diesel engines by capturing both their spatial periodicity and axial motion. The Method of Varying Amplitudes is employed in the analysis. It is shown that the compound wave traveling in the axially moving periodic string comprises many components with different frequencies and wavenumbers. This is in contrast to non-moving periodic structures, for which all components of the corresponding compound wave feature the same frequency. Due to this "multi-frequency" character of the wave motion, the conventional notion of frequency band-gaps appears to be not applicable for the moving periodic strings. Thus, for such structures, by frequency band-gaps it is proposed to understand frequency ranges in which the primary component of the compound wave attenuates. Such frequency band-gaps can be present for a moving periodic string, but only if its axial velocity is lower than the transverse wave speed, and, the higher the axial velocity, the narrower the frequency band-gaps. The revealed effects could be of potential importance for applications, e.g. they indicate that due to spatial inhomogeneity, oscillations of axially moving periodic chains always involve a multitude of frequencies.

Non-proximity resonant tunneling in multi-core photonic band gap fibers: An efficient mechanism for engineering highly-selective ultra-narrow band pass splitters

NASA Astrophysics Data System (ADS)

Florous, Nikolaos J.; Saitoh, Kunimasa; Murao, Tadashi; Koshiba, Masanori; Skorobogatiy, Maksim

2006-05-01

The objective of the present investigation is to demonstrate the possibility of designing compact ultra-narrow band-pass filters based on the phenomenon of non-proximity resonant tunneling in multi-core photonic band gap fibers (PBGFs). The proposed PBGF consists of three identical air-cores separated by two defected air-holes which act as highly-selective resonators. With a fine adjustment of the design parameters associated with the resonant-air-holes, phase matching at two distinct wavelengths can be achieved, thus enabling very narrow-band resonant directional coupling between the input and the two output cores. The validation of the proposed design is ensured with an accurate PBGF analysis based on finite element modal and beam propagation algorithms. Typical characteristics of the proposed device over a single polarization are: reasonable short coupling length of 2.7 mm, dual bandpass transmission response at wavelengths of 1.339 and 1.357 μm, with corresponding full width at half maximum bandwidths of 1.2 nm and 1.1 nm respectively, and a relatively high transmission of 95% at the exact resonance wavelengths. The proposed ultra-narrow band-pass filter can be employed in various applications such as all-fiber bandpass/bandstop filtering and resonant sensors.

Non-proximity resonant tunneling in multi-core photonic band gap fibers: An efficient mechanism for engineering highly-selective ultra-narrow band pass splitters.

PubMed

Florous, Nikolaos J; Saitoh, Kunimasa; Murao, Tadashi; Koshiba, Masanori; Skorobogatiy, Maksim

2006-05-29

The objective of the present investigation is to demonstrate the possibility of designing compact ultra-narrow band-pass filters based on the phenomenon of non-proximity resonant tunneling in multi-core photonic band gap fibers (PBGFs). The proposed PBGF consists of three identical air-cores separated by two defected air-holes which act as highly-selective resonators. With a fine adjustment of the design parameters associated with the resonant-air-holes, phase matching at two distinct wavelengths can be achieved, thus enabling very narrow-band resonant directional coupling between the input and the two output cores. The validation of the proposed design is ensured with an accurate PBGF analysis based on finite element modal and beam propagation algorithms. Typical characteristics of the proposed device over a single polarization are: reasonable short coupling length of 2.7 mm, dual bandpass transmission response at wavelengths of 1.339 and 1.357 mum, with corresponding full width at half maximum bandwidths of 1.2 nm and 1.1 nm respectively, and a relatively high transmission of 95% at the exact resonance wavelengths. The proposed ultra-narrow band-pass filter can be employed in various applications such as all-fiber bandpass/bandstop filtering and resonant sensors.

State Test Score Trends through 2008-09, Part 2: Slow and Uneven Progress in Narrowing Gaps

ERIC Educational Resources Information Center

Kober, Nancy; Chudowsky, Naomi; Chudowsky, Victor

2010-01-01

After eight years of implementing the federal No Child Left Behind Act (NCLB) and other school reforms, how much progress have states, school districts, and schools made in raising achievement for students from all backgrounds and closing achievement gaps based on race, ethnicity, income, and gender? To help answer this question, the Center on…

The Narrowing Gap in New York City Teacher Qualifications and Its Implications for Student Achievement in High-Poverty Schools

ERIC Educational Resources Information Center

Boyd, Donald; Lankford, Hamilton; Loeb, Susanna; Rockoff, Jonah; Wyckoff, James

2008-01-01

Understanding what makes an effective teacher, as well as how teachers sort by their effectiveness across schools, is central to understanding and addressing student achievement gaps. Prior studies have found substantial sorting of teachers across schools, with the schools with the highest proportions of poor, non-white, and low-scoring students…

Reforms that Could Help Narrow the Achievement Gap. Policy Perspectives

ERIC Educational Resources Information Center

Rothstein, Richard

2006-01-01

Americans have concluded that the achievement gap is the fault of "failing schools" because it makes no common sense that it could be otherwise. After all, how much money a family has, or a child's skin color, should not influence how well that child learns to read. If teachers know how to teach and if schools permit no distractions, children…

Examining the Achievement Gap: The Effectiveness of African American Teachers Instructing African American Students in Kansas City Public Schools

ERIC Educational Resources Information Center

Campbell, Judith Jordan

2013-01-01

Over several years the American public educational system has failed to address one of the most infuriating problems faced by our nation, narrowing the achievement gap in urban districts with urban learners. Historically, minority students have not paralleled the academic performance of their White counterparts. This holds true with standardized…

Gender Gap in Science, Technology, Engineering, and Mathematics (STEM): Current Knowledge, Implications for Practice, Policy, and Future Directions

ERIC Educational Resources Information Center

Wang, Ming-Te; Degol, Jessica L.

2017-01-01

Although the gender gap in math course-taking and performance has narrowed in recent decades, females continue to be underrepresented in math-intensive fields of Science, Technology, Engineering, and Mathematics (STEM). Career pathways encompass the ability to pursue a career as well as the motivation to employ that ability. Individual differences…

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

Deformation of the Tonga Slab: Evidence for Interaction with a Small-scale Secondary Plume in the Transition Zone

NASA Astrophysics Data System (ADS)

Billen, M. I.; Bikoba, J. Z.; Tarlow, S.

2015-12-01

Magali I. Billen and John Z. BikobaThe Tonga Slab is the most seismically active subduction zone providing a uniquely detailed picture of the internal deformation of the slab, with apparent warping and folding, from the surface through the transition zone. Here, we investigate the dynamical origin of a irregular feature in the seismicity within the transition zone located at 21-28oS, using 3D visualization and analysis of the seismicity and compression/tension (P/T) axis from the moment tensor solutions to characterize the geometry of, and the orientation of forces acting on, the slab. This irregular feature can be described as narrow region of upward deflection of the slab, with a gap in seismicity beyond (down-dip of) the deflected region, and flanked by two narrow V-shaped gaps in seismicity suggestive of tearing of the slab. The P/T axis show a dominate down-dip orientation of the P axis above the deflection point, which rotate to a nearly vertical orientation within the central region of the deflected slab. The adjacent attached regions (down-dip of the two flanking slab gaps) also have rotated and more heterogeneous P/T axis orientations. In contrast, the adjacent section of the slab to the north of 21oS has continuous seismicity throughout the transition zone, with a roughly uniform planar shape, and generally down-dip orientation of the P axis. We explore three possible hypothesis for the observed deformation including: 1) deflection due to a buoyant metastable olivine wedge, 2) a buckling feature in the slab as previously proposed by Myhill (GJI., 2013), and interaction with a small-scale, secondary plume upwelling below the slab. If the newly-observed gaps in seismicity indicate physical gaps or significant thinning of the slab, then these observations are not consistent with the buckling hypothesis. The lack of significant along-strike variation in slab age or subduction rate also suggests that a localized region of metastable olivine is unlikely. Therefore, we test the third hypothesis using a simple 3D geodynamical model of a planar dipping slab overlying a localized buoyant upwelling (radius < 150 km). We present comparisons of the observations to the model predictions for the subsequent deformation of the slab and orientations of principal stress axis within the slab.

Band-gap narrowing and magnetic behavior of Ni-doped Ba(Ti0.875Ce0.125)O3 thin films

NASA Astrophysics Data System (ADS)

Zhou, Wenliang; Deng, Hongmei; Yu, Lu; Yang, Pingxiong; Chu, Junhao

2015-11-01

Band-gap narrowing and magnetic effects have been observed in a Ni-doped Ba(Ti0.875Ce0.125)O3 (BTC) thin film. Structural characterizations and microstructural analysis show that the as-prepared Ba(Ti0.75Ce0.125Ni0.125)O3-δ (BTCN) thin film exhibits a cubic perovskite structure with an average grain size of 25 nm. The Ce doping at the Ti-site results in an increasing perovskite volume to favour an O-vacancy-stabilized Ni2+ substitution. Raman spectroscopy, however, shows the cubic symmetry of crystalline structures is locally lowered by the presence of dopants, significantly deviating from the ideal Pm3m space group. Moreover, BTCN presents a narrowed band-gap, much smaller than that of BaTiO3 and BTC, due to new states of both the highest occupied molecular orbital and the lowest unoccupied molecular orbital in an electronic structure with the presence of Ni. Also, magnetic enhancement driven by co-doping has been confirmed in the films, which mainly stems from the exchange interaction of Ni2+ ions via an electron trapped in a bridging oxygen vacancy. These findings may open an avenue to discover and design optimal perovskite compounds for solar-energy devices and information storage.

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.

TiO2 film/Cu2O microgrid heterojunction with photocatalytic activity under solar light irradiation.

PubMed

Zhang, Junying; Zhu, Hailing; Zheng, Shukai; Pan, Feng; Wang, Tianmin

2009-10-01

Coupling a narrow-band-gap semiconductor with TiO(2) is an effective method to produce photocatalysts that work under UV-vis light irradiation. Usually photocatalytic coupled-semiconductors exist mainly as powders, and photocatalytic activity is only favored when a small loading amount of narrow-band-gap semiconductor is used. Here we propose a heavy-loading photocatalyst configuration in which 51% of the surface of the TiO(2) film is covered by a Cu(2)O microgrid. The coupled system shows higher photocatalytic activity under solar light irradiation than TiO(2) and Cu(2)O films. This improved performance is due to the efficient charge transfer between the two phases and the similar opportunity each has to be exposed to irradiation and adsorbates.

Medicare Program Associated With Narrowing Hospital Readmission Disparities Between Black And White Patients.

PubMed

Figueroa, José F; Zheng, Jie; Orav, E John; Epstein, Arnold M; Jha, Ashish K

2018-04-01

The Hospital Readmissions Reduction Program has been associated with improvements in readmission rates, yet little is known about its effect on racial disparities. We compared trends in thirty-day readmission rates for congestive heart failure, acute myocardial infarction, and pneumonia among non-Hispanic whites versus non-Hispanic blacks, and among minority-serving hospitals versus others. During the penalty-free implementation period (April 2010-September 2012), readmission rates improved over pre-implementation trends (January 2007-March 2010) for both whites and blacks, with a significantly greater decline among blacks than among whites (-0.45 percent versus -0.36 percent per quarter, respectively). In the period October 2012-December 2014, after penalties began, readmission improvements slowed for both races. Following a similar pattern, minority-serving hospitals saw greater reductions in readmissions than other hospitals did. Despite the narrowing of the two race-based gaps after announcement of the Hospital Readmissions Reduction Program, both persist. It remains to be seen whether new policy efforts will narrow these gaps and reduce the disproportionately high penalties that minority-serving hospitals face.

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…

Two Sides of the Same Coin: U. S. "Residual" Inequality and the Gender Gap

ERIC Educational Resources Information Center

Bacolod, Marigee P.; Blum, Bernardo S.

2010-01-01

We show that the narrowing gender gap and the growth in earnings inequality are consistent with a simple model in which skills are heterogeneous, and the growth in skill prices has been particularly strong for skills with which women are well endowed. Empirical analysis of DOT, CPS, and NLSY79 data finds evidence to support this model. A large…

The Importance of Segregation, Discrimination, Peer Dynamics, and Identity in Explaining Trends in the Racial Achievement Gap. NBER Working Paper No. 16257

ERIC Educational Resources Information Center

Fryer, Roland G., Jr.

2010-01-01

After decades of narrowing, the achievement gap between black and white school children widened in the 1990s--a period when the labor market rewards for education were increasing. This presents an important puzzle for economists. In this chapter, I investigate the extent to which economic models of segregation, information-based discrimination,…

Narrowing the College Opportunity Gap: Helping Students and Families Navigate the Financial Aid Process

ERIC Educational Resources Information Center

Owen, Laura

2012-01-01

The number of students enrolling in post-secondary institutions in the U.S. has slowly been rising over the last 10 years, yet gaps continue to exist in terms of who attends college and persists through graduation. Minority and low income students often lack the guidance needed to navigate the college enrollment process and as a result, remain…

"Narrowing the transmission gap: A synthesis of three decades of research on intergenerational transmission of attachment": Correction.

PubMed

2018-04-01

Reports an error in "Narrowing the transmission gap: A synthesis of three decades of research on intergenerational transmission of attachment" by Marije L. Verhage, Carlo Schuengel, Sheri Madigan, R. M. Pasco Fearon, Mirjam Oosterman, Rosalinda Cassibba, Marian J. Bakermans-Kranenburg and Marinus H. van IJzendoorn ( Psychological Bulletin , 2016[Apr], Vol 142[4], 337-366). In the article, there are errors in Table 7. The percentages of the attachment classifications do not add up to 100%. The corrected version of Table 7 is provided in the erratum. (The following abstract of the original article appeared in record 2015-55801-001.) Twenty years ago, meta-analytic results (k = 19) confirmed the association between caregiver attachment representations and child-caregiver attachment (Van IJzendoorn, 1995). A test of caregiver sensitivity as the mechanism behind this intergenerational transmission showed an intriguing "transmission gap." Since then, the intergenerational transmission of attachment and the transmission gap have been studied extensively, and now extend to diverse populations from all over the globe. Two decades later, the current review revisited the effect sizes of intergenerational transmission, the heterogeneity of the transmission effects, and the size of the transmission gap. Analyses were carried out with a total of 95 samples (total N = 4,819). All analyses confirmed intergenerational transmission of attachment, with larger effect sizes for secure-autonomous transmission (r = .31) than for unresolved transmission (r = .21), albeit with significantly smaller effect sizes than 2 decades earlier (r = .47 and r = .31, respectively). Effect sizes were moderated by risk status of the sample, biological relatedness of child-caregiver dyads, and age of the children. Multivariate moderator analyses showed that unpublished and more recent studies had smaller effect sizes than published and older studies. Path analyses showed that the transmission could not be fully explained by caregiver sensitivity, with more recent studies narrowing but not bridging the "transmission gap." Implications for attachment theory as well as future directions for research are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Pulse stretcher for narrow pulses

NASA Technical Reports Server (NTRS)

Lindsey, R. S., Jr. (Inventor)

1974-01-01

A pulse stretcher for narrow pulses is presented. The stretcher is composed of an analog section for processing each arriving analog pulse and a digital section with logic for providing command signals to the gates and switches in the analog section.

Is "Gender Gap" Narrowing?

ERIC Educational Resources Information Center

Science, 1991

1991-01-01

The question as to whether males and females have different kinds of intellectual abilities is addressed. The evidence that there are some differences in cognition and perception between men and women is reviewed. (KR)

Photovoltaic measurement of bandgap narrowing in moderately doped silicon

NASA Astrophysics Data System (ADS)

del Alamo, Jesus A.; Swanson, Richard M.; Lietoila, Arto

1983-05-01

Solar cells have been fabricated on n-type and p-type moderately doped Si. The shrinkage of the Si bandgap has been obtained by measuring the internal quantum efficiency in the near infrared spectrum ( hv = 1.00-1.25 eV) around the fundamental absorption edge. The results agree with previous optical measurements of bandgap narrowing in Si. It is postulated that this optically-determined bandgap narrowing is the rigid shrinkage of the forbidden gap due to many-body effects. The "device bandgap narrowing" obtained by measuring the pn product in bipolar devices leads to discrepant values because (i) the density of states in the conduction and valence band is modified due to the potential fluctuations originated in the variations in local impurity density, and (ii) the influence of Fermi-Dirac statistics.

Modeling and Simulation of Ceramic Arrays to Improve Ballaistic Performance

DTIC Science & Technology

2013-11-01

2219 , 2000 Tile gap is found to increase the DoP as compared to One Tile tiles The next step will be run simulations on narrower and wider gap sizes...experiments described in reference - ARL-TR- 2219 , 2000 □ Tile gap is found to increase the DoP as compared to One Tile tiles □ The next step will be run...L| Al m ^ s\\cr V^ 1 v^ □ Smoothed-particle hydrodynamics (SPH) used for all parts □ SPH size = 0.40-mm, totaling 278k

Women's Earnings: An Overview.

ERIC Educational Resources Information Center

Bowler, Mary

1999-01-01

Over the past 20 years, women's real earnings rose whereas those of men declined. Even as the gender pay gap narrowed, earnings differences between white women and black and Hispanic women continued to grow. (Author)

Effects of Surface Roughness and Mechanical Properties of Cover-Layer on Near-Field Optical Recording

NASA Astrophysics Data System (ADS)

Kim, Jin-Hong; Lee, Jun-Seok; Lim, Jungshik; Seo, Jung-Kyo

2009-03-01

Narrow gap distance in cover-layer incident near-field recording (NFR) configuration causes a collision problem in the interface between a solid immersion lens and a disk surface. A polymer cover-layer with smooth surface results in a stable gap servo while a nanocomposite cover-layer with high refractive index shows a collision problem during the gap servo test. Even though a dielectric cover-layer, in which the surface is rougher than the polymer, supplements the mechanical properties, an unclear eye pattern due to an unstable gap servo can be obtained after a chemical mechanical polishing. Not only smooth surface but also good mechanical properties of cover-layer are required for the stable gap servo in the NFR.

Polarization State of Light Scattered from Quantum Plasmonic Dimer Antennas.

PubMed

Yang, Longkun; Wang, Hancong; Fang, Yan; Li, Zhipeng

2016-01-26

Plasmonic antennas are able to concentrate and re-emit light in a controllable manner through strong coupling between metallic nanostructures. Only recently has it found that quantum mechanical effects can drastically change the coupling strength as the feature size approaches atomic scales. Here, we present a comprehensive experimental and theoretical study of the evolution of the resonance peak and its polarization state as the dimer-antenna gap narrows to subnanometer scale. We clearly can identify the classical plasmonic regime, a crossover regime where nonlocal screening plays an important role, and the quantum regime where a charge transfer plasmon appears due to interparticle electron tunneling. Moreover, as the gap decreases from tens of to a few nanometers, the bonding dipole mode tends to emit photons with increasing polarizability. When the gap narrows to quantum regime, a significant depolarization of the mode emission is observed due to the reduction of the charge density of coupled quantum plasmons. These results would be beneficial for the understanding of quantum effects on emitting-polarization of nanoantennas and the development of quantum-based photonic nanodevices.

Development of Sample Verification System for Sample Return Missions

NASA Technical Reports Server (NTRS)

Toda, Risaku; McKinney, Colin; Jackson, Shannon P.; Mojarradi, Mohammad; Trebi-Ollennu, Ashitey; Manohara, Harish

2011-01-01

This paper describes the development of a proof of-concept sample verification system (SVS) for in-situ mass measurement of planetary rock and soil sample in future robotic sample return missions. Our proof-of-concept SVS device contains a 10 cm diameter pressure sensitive elastic membrane placed at the bottom of a sample canister. The membrane deforms under the weight of accumulating planetary sample. The membrane is positioned in proximity to an opposing substrate with a narrow gap. The deformation of the membrane makes the gap to be narrower, resulting in increased capacitance between the two nearly parallel plates. Capacitance readout circuitry on a nearby printed circuit board (PCB) transmits data via a low-voltage differential signaling (LVDS) interface. The fabricated SVS proof-of-concept device has successfully demonstrated approximately 1pF/gram capacitance change

The Effect of High N-DOPED Anatase TiO2 on the Band Gap Narrowing and Redshift by First-Principles

NASA Astrophysics Data System (ADS)

Hou, Qingyu; Jin, Yongjun; Ying, Chun; Zhao, Erjun; Zhang, Yue; Dong, Hongying

2012-10-01

Anatase TiO2 supercells were studied by first-principles, in which one was undoped and another three were high N-doping. Partial densities of states, band structure, population and absorption spectrum were calculated. The calculated results indicated that in the condition of TiO2-xNx (x = 0.0625, 0.125, 0.25), the higher the doping concentration is, the shorter will be the lattice parameters parallel to the direction of c-axis. The strength of covalent bond significantly varied. The formation energy increases at first, and then decreases. The doping models become less stable as N-doping concentration increases. Meanwhile, the narrower the band gap is, the more significant will be the redshift, which is in agreement with the experimental results.

Competitive behavior of photons contributing to junction voltage jump in narrow band-gap semiconductor multi-quantum-well laser diodes at lasing threshold

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

Feng, Liefeng, E-mail: fengliefeng@tju.edu.cn, E-mail: lihongru@nankai.edu.cn; Yang, Xiufang; Wang, Cunda

2015-04-15

The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I{sub th}{sup l} and I{sub th}{sup u}, as shown in Fig. 2; I{sub th}{sup l} is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I{sub th}{sup u}more » is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V{sub j}) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I{sub th}{sup l} and I{sub th}{sup u}. The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region.« less

An Exceptionally Narrow Band-Gap (∼4 eV) Silicate Predicted in the Cubic Perovskite Structure: BaSiO3.

PubMed

Hiramatsu, Hidenori; Yusa, Hitoshi; Igarashi, Ryo; Ohishi, Yasuo; Kamiya, Toshio; Hosono, Hideo

2017-09-05

The electronic structures of 35 A 2+ B 4+ O 3 ternary cubic perovskite oxides, including their hypothetical chemical compositions, were calculated by a hybrid functional method with the expectation that peculiar electronic structures and unique carrier transport properties suitable for semiconductor applications would be hidden in high-symmetry cubic perovskite oxides. We found unique electronic structures of Si-based oxides (A = Mg, Ca, Sr, and Ba, and B = Si). In particular, the unreported cubic BaSiO 3 has a very narrow band gap (4.1 eV) compared with conventional nontransition-metal silicates (e.g., ∼9 eV for SiO 2 and the calculated value of 7.3 eV for orthorhombic BaSiO 3 ) and a small electron effective mass (0.3m 0 , where m 0 is the free electron rest mass). The narrow band gap is ascribed to the nonbonding state of Si 3s and the weakened Madelung potential. The existence of the predicted cubic perovskite structure of BaSiO 3 was experimentally verified by applying a high pressure of 141 GPa. The present finding indicates that it could be possible to develop a new transparent oxide semiconductor of earth abundant silicates if the symmetry of its crystal structure is appropriately chosen. Cubic BaSiO 3 is a candidate for high-performance oxide semiconductors if this phase can be stabilized at room temperature and ambient pressure.

Narrowing the Achievement Gap in a (Re) Segregated Urban School District: Research, Policy and Practice. The Achievement Gap, Research, Practice, and Policy

ERIC Educational Resources Information Center

Ikpa, Vivian W.; McGuire, C. Kent

2009-01-01

The interplay between sociopolitical forces and economic agendas becomes apparent when one examines the June 28, 2007 United States Supreme Court Decision, Parents Involved In Community Schools v. Seattle School District . In a reversal of the 1954 Brown Decision, the United States Supreme Court ruled that public schools could not use race as a…

Beginning with the End in Mind: The School District Office Leadership Role in Closing the Graduation Gap for At-Risk Students

ERIC Educational Resources Information Center

Mac Iver, Martha Abele

2010-01-01

Increasing high school graduation rates is a systemic issue, not just a school level issue. The district office therefore has a key role to play in narrowing the graduation gap and ensuring that more students earn their high school diplomas well-equipped for college or career. This article focuses first on what school districts have typically done…

The Role of Maternal Education during Educational Expansion for Children in Sub-Saharan Africa. CREATE Pathways to Access. Research Monograph No. 64

ERIC Educational Resources Information Center

Sabates, Ricardo; Fernandez, Jimena Hernandez; Lewin, Keith M.

2011-01-01

This paper analyses the gap in educational access according to maternal education over a 10 year period using evidence from the Demographic Health Surveys (DHS) in six African countries. To investigate the narrowing or widening in the gap in educational access according to maternal education, two cohorts of children and one cohort of mothers were…

Nonlinear Optical Interactions in Semiconductors.

DTIC Science & Technology

1985-12-10

Physique du Solide et Energie Solaire We had on-going interaction with Dr. Christian Verie on the growth of high quality narrow-gap semiconductor crystals...The band gap energy of the semiconductor decreases with increasing temperature. Consequently, the absorption of light in the energy region of the...gas and, more importantly, will modulate the electron energy at the difference frequency, wI - 02" Under ordinary circumstances such an energy (or

Large Scale Integrated Circuits for Military Applications.

DTIC Science & Technology

1977-05-01

economic incentive for riarrowing this gap is examined, y (U)^wo"categories of cost are analyzed: the direct life cycle cost of the integrated circuit...dependence of these costs on the physical charac- teristics of the integrated circuits is discussed. (U) The economic and physical characteristics of... economic incentive for narrowing this gap is examined. Two categories of cost are analyzed: the direct life cycle cost of the integrated circuit

Developing a pulse trigger generator for a three-electrode spark-gap switch in a transversely excited atmospheric CO2 laser.

PubMed

Wang, Jingyuan; Guo, Lihong; Zhang, Xingliang

2016-04-01

To improve the probability and stability of breakdown discharge in a three-electrode spark-gap switch for a high-power transversely excited atmospheric CO2 laser and to improve the efficiency of its trigger system, we developed a high-voltage pulse trigger generator based on a two-transistor forward converter topology and a multiple-narrow-pulse trigger method. Our design uses a narrow high-voltage pulse (10 μs) to break down the hyperbaric gas between electrodes of the spark-gap switch; a dry high-voltage transformer is used as a booster; and a sampling and feedback control circuit (mainly consisting of a SG3525 and a CD4098) is designed to monitor the spark-gap switch and control the frequency and the number of output pulses. Our experimental results show that this pulse trigger generator could output high-voltage pulses (number is adjusted) with an amplitude of >38 kV and a width of 10 μs. Compared to a conventional trigger system, our design had a breakdown probability increased by 2.7%, an input power reduced by 1.5 kW, an efficiency increased by 0.12, and a loss reduced by 1.512 kW.

Near-edge band structures and band gaps of Cu-based semiconductors predicted by the modified Becke-Johnson potential plus an on-site Coulomb U

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

Zhang, Yubo; Zhang, Jiawei; Wang, Youwei

Diamond-like Cu-based multinary semiconductors are a rich family of materials that hold promise in a wide range of applications. Unfortunately, accurate theoretical understanding of the electronic properties of these materials is hindered by the involvement of Cu d electrons. Density functional theory (DFT) based calculations using the local density approximation or generalized gradient approximation often give qualitative wrong electronic properties of these materials, especially for narrow-gap systems. The modified Becke-Johnson (mBJ) method has been shown to be a promising alternative to more elaborate theory such as the GW approximation for fast materials screening and predictions. However, straightforward applications of themore » mBJ method to these materials still encounter significant difficulties because of the insufficient treatment of the localized d electrons. We show that combining the promise of mBJ potential and the spirit of the well-established DFT + U method leads to a much improved description of the electronic structures, including the most challenging narrow-gap systems. A survey of the band gaps of about 20 Cu-based semiconductors calculated using the mBJ + U method shows that the results agree with reliable values to within ±0.2 eV.« less

Decomposing the gap in missed opportunities for vaccination between poor and non-poor in sub-Saharan Africa: A Multicountry Analyses.

PubMed

Ndwandwe, Duduzile; Uthman, Olalekan A; Adamu, Abdu A; Sambala, Evanson Z; Wiyeh, Alison B; Olukade, Tawa; Bishwajit, Ghose; Yaya, Sanni; Okwo-Bele, Jean-Marie; Wiysonge, Charles S

2018-04-24

Understanding the gaps in missed opportunities for vaccination (MOV) in sub-Saharan Africa would inform interventions for improving immunisation coverage to achieving universal childhood immunisation. We aimed to conduct a multicountry analyses to decompose the gap in MOV between poor and non-poor in SSA. We used cross-sectional data from 35 Demographic and Health Surveys in SSA conducted between 2007 and 2016. Descriptive statistics used to understand the gap in MOV between the urban poor and non-poor, and across the selected covariates. Out of the 35 countries included in this analysis, 19 countries showed pro-poor inequality, 5 showed pro-non-poor inequality and remaining 11 countries showed no statistically significant inequality. Among the countries with statistically significant pro-illiterate inequality, the risk difference ranged from 4.2% in DR Congo to 20.1% in Kenya. Important factors responsible for the inequality varied across countries. In Madagascar, the largest contributors to inequality in MOV were media access, number of under-five children, and maternal education. However, in Liberia media access narrowed inequality in MOV between poor and non-poor households. The findings indicate that in most SSA countries, children belonging to poor households are most likely to have MOV and that socio-economic inequality in is determined not only by health system functions, but also by factors beyond the scope of health authorities and care delivery system. The findings suggest the need for addressing social determinants of health.

Edge currents shunt the insulating bulk in gapped graphene

NASA Astrophysics Data System (ADS)

Zhu, M. J.; Kretinin, A. V.; Thompson, M. D.; Bandurin, D. A.; Hu, S.; Yu, G. L.; Birkbeck, J.; Mishchenko, A.; Vera-Marun, I. J.; Watanabe, K.; Taniguchi, T.; Polini, M.; Prance, J. R.; Novoselov, K. S.; Geim, A. K.; Ben Shalom, M.

2017-02-01

An energy gap can be opened in the spectrum of graphene reaching values as large as 0.2 eV in the case of bilayers. However, such gaps rarely lead to the highly insulating state expected at low temperatures. This long-standing puzzle is usually explained by charge inhomogeneity. Here we revisit the issue by investigating proximity-induced superconductivity in gapped graphene and comparing normal-state measurements in the Hall bar and Corbino geometries. We find that the supercurrent at the charge neutrality point in gapped graphene propagates along narrow channels near the edges. This observation is corroborated by using the edgeless Corbino geometry in which case resistivity at the neutrality point increases exponentially with increasing the gap, as expected for an ordinary semiconductor. In contrast, resistivity in the Hall bar geometry saturates to values of about a few resistance quanta. We attribute the metallic-like edge conductance to a nontrivial topology of gapped Dirac spectra.

Heavy doping effects in high efficiency silicon solar cells

NASA Technical Reports Server (NTRS)

Lindholm, F. A.

1984-01-01

Several of the key parameters describing the heavily doped regions of silicon solar cells are examined. The experimentally determined energy gap narrowing and minority carrier diffusivity and mobility are key factors in the investigation.

A High-Resolution Endoscope of Small Diameter Using Electromagnetically Vibration of Single Fiber

NASA Astrophysics Data System (ADS)

Matsunaga, Tadao; Hino, Ryunosuke; Makishi, Wataru; Esashi, Masayoshi; Haga, Yoichi

For high resolution visual inspection in the narrow space of the human body, small diameter endoscope has been developed which utilize electromagnetically vibration of single fiber. Thin endoscopes are effective for inspection in the narrow space of the human body, for example, in the blood vessel, lactiferous duct for detection infiltration of breast cancer, and periodontal gap between gingiva and tooth. This endoscope consists of single optical fiber and photofabricated driving coils. A collimator lens and a cylindrical permanent magnet are fixed on the optical fiber, and the tilted driving coils have been patterned on a 1.08 mm outer diameter thin tube. The fiber is positioned at the center of the tube which is patterned the coils. When an electrical alternating current at the resonance frequency is supplied to the coils, the permanent magnet which is fixed to the fiber is vibrated electromagnetically and scanned one or two dimensionally. This paper reports small diameter endoscope by using electromagnetically vibration of single fiber. Optical coherence tomography imaging has also been carried out with the fabricated endoscope and cross-section image of sub-surface skin of thumb was observed.

Study of education disparities and health information seeking behavior.

PubMed

Lorence, Daniel; Park, Heeyoung

2007-02-01

This exploratory technology assessment examines how educational characteristics of health information seekers are associated with access to computers, the Internet, and online health information. Specifically, we examine (1) if there exists significant variation across identified health technology user groups regarding access to online health information, and (2) if differences between education levels have narrowed, remained constant, or widened over recent years, following national educational initiatives to narrow the technology gap for low-education user groups. Using a stratified sample from national tracking survey data, we find that recent policy initiatives under national technology access and other programs have demonstrated little effect in narrowing the digital divide for low-education users of web-based technologies.

Trends in suicidality among sexual minority and heterosexual students in a Canadian population-based cohort study

PubMed Central

Peter, Tracey; Edkins, Tamara; Watson, Ryan; Adjei, Jones; Homma, Yuko; Saewyc, Elizabeth

2017-01-01

Objectives Despite evidence from numerous studies that document disparities in suicidality for sexual minorities, few have investigated whether or not these trends have improved over time, which is the objective of the current study. Methods Using school-based population data over a 15-year period (1998 to 2013), multivariate logistic regressions were used to calculate age-adjusted odds ratios separately by gender. Interactions were included to test widening or narrowing disparities within orientation groups, which makes this one of the first studies to test whether gaps in disparities between heterosexual and sexual minorities have widened or narrowed over time. Results Results show that sexual minority youth are persistently at a greater risk for suicidal behaviour, a trend that has continued particularly for bisexual youth of both sexes. Results also suggest that the gap in suicidal behaviour is widening among some female sexual orientation groups, yet narrowing for other male sexual orientation groups. Conclusions These findings have important public health implications, especially since we see decreases in suicidal behaviour for heterosexual adolescents, but not in the same way for many sexual minority youth, despite advances in social acceptance of gay, lesbian, and bisexual issues in North America. PMID:29326961

Bioactive glass fillers reduce bacterial penetration into marginal gaps for composite restorations

PubMed Central

Khvostenko, D.; Hilton, T. J.; Ferracane, J. L.; Mitchell, J. C.; Kruzic, J. J.

2015-01-01

Objectives Bioactive glass (BAG) is known to possess antimicrobial and remineralizing properties; however, the use of BAG as a filler for resin based composite restorations to slow recurrent caries has not been studied. Accordingly, the objective of this study was to investigate the effect of 15 wt% BAG additions to a resin composite on bacterial biofilms penetrating into marginal gaps of simulated tooth fillings in vitro during cyclic mechanical loading. Methods Human molars were machined into approximately 3 mm thick disks of dentin and 1.5–2 mm deep composite restorations were placed. A narrow 15–20 micrometer wide dentin-composite gap was allowed to form along half of the margin by not applying dental adhesive to that region. Two different 72 wt% filled composites were used, one with 15 wt% BAG filler (15BAG) and the balance silanated strontium glass and one filled with OX-50 and silanated strontium glass without BAG (0BAG – control). Samples of both groups had Streptococcus mutans biofilms grown on the surface and were tested inside a bioreactor for two weeks while subjected to periods of cyclic mechanical loading. After post-test biofilm viability was confirmed, each specimen was fixed in glutaraldehyde, gram positive stained, mounted in resin and cross-sectioned to reveal the gap profile. Depth of biofilm penetration for 0BAG and 15BAG was quantified as the fraction of gap depth. The data were compared using a Student’s t-test. Results The average depth of bacterial penetration into the marginal gap for the 15BAG samples was significantly smaller (~61%) in comparison to 0BAG, where 100% penetration was observed for all samples with the biofilm penetrating underneath of the restoration in some cases. Significance BAG containing resin dental composites reduce biofilm penetration into marginal gaps of simulated tooth restorations. This suggests BAG containing composites may have the potential to slow the development and propagation of secondary tooth decay at restoration margins. PMID:26621028

The temperature-dependency of the optical band gap of ZnO measured by electron energy-loss spectroscopy in a scanning transmission electron microscope

NASA Astrophysics Data System (ADS)

Granerød, Cecilie S.; Galeckas, Augustinas; Johansen, Klaus Magnus; Vines, Lasse; Prytz, Øystein

2018-04-01

The optical band gap of ZnO has been measured as a function of temperature using Electron Energy-Loss Spectroscopy (EELS) in a (Scanning) Transmission Electron Microscope ((S)TEM) from approximately 100 K up towards 1000 K. The band gap narrowing shows a close to linear dependency for temperatures above 250 K and is accurately described by Varshni, Bose-Einstein, Pässler and Manoogian-Woolley models. Additionally, the measured band gap is compared with both optical absorption measurements and photoluminescence data. STEM-EELS is here shown to be a viable technique to measure optical band gaps at elevated temperatures, with an available temperature range up to 1500 K and the benefit of superior spatial resolution.

Low-temperature magnetotransport of the narrow-gap semiconductor FeSb2

NASA Astrophysics Data System (ADS)

Takahashi, H.; Okazaki, R.; Yasui, Y.; Terasaki, I.

2011-11-01

We present a study of the magnetoresistance and Hall effect in the narrow-gap semiconductor FeSb2 at low temperatures. Both the electrical and Hall resistivities show unusual magnetic field dependence in the low-temperature range where a large Seebeck coefficient was observed. By applying a two-carrier model, we find that the carrier concentration decreases from 1 down to 10-4 ppm/unit cell and the mobility increases from 2000 to 28 000 cm2/Vs with decreasing temperature from 30 down to 4 K. At lower temperatures, the magnetoresistive behavior drastically changes and a negative magnetoresistance is observed at 3 K. These low-temperature behaviors are reminiscent of the low-temperature magnetotransport observed in doped semiconductors such as As-doped Ge, which is well described by a weak-localization picture. We argue a detailed electronic structure in FeSb2 inferred from our observations.

Pressure dependence of transverse acoustic phonon energy in ferropericlase across the spin transition.

PubMed

Fukui, Hiroshi; Baron, Alfred Q R; Ishikawa, Daisuke; Uchiyama, Hiroshi; Ohishi, Yasuo; Tsuchiya, Taku; Kobayashi, Hisao; Matsuzaki, Takuya; Yoshino, Takashi; Katsura, Tomoo

2017-06-21

We investigated transverse acoustic (TA) phonons in iron-bearing magnesium oxide (ferropericlase) up to 56 GPa using inelastic x-ray scattering (IXS). The results show that the energy of the TA phonon far from the Brillouin zone center suddenly increases with increasing pressure above the spin transition pressure of ferropericlase. Ab initio calculations revealed that the TA phonon energy far from the Brillouin zone center is higher in the low-spin state than in the high spin state; that the TA phonon energy depend weakly on pressure; and that the energy gap between the TA and the lowest-energy-optic phonons is much narrower in the low-spin state than in the high-spin state. This allows us to conclude that the anomalous behavior of the TA mode in the present experiments is the result of gap narrowing due to the spin transition and explains contradictory results in previous experimental studies.

Modeling Bi-induced changes in the electronic structure of GaAs1-xBix alloys

NASA Astrophysics Data System (ADS)

Virkkala, Ville; Havu, Ville; Tuomisto, Filip; Puska, Martti J.

2013-12-01

We suggested recently [V. Virkkala , Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.88.035204 88, 035204 (2013)] that the band-gap narrowing in dilute GaAs1-xNx alloys can be explained to result from the broadening of the localized N states due to the N-N interaction along the zigzag chains in the <110> directions. In that study our tight-binding modeling based on first-principles density-functional calculations took into account the random distribution of N atoms in a natural way. In this work we extend our modeling to GaAs1-xBix alloys. Our results indicate that Bi states mix with host material states. However, the states near the valence-band edge agglomerate along the zigzag chains originating from individual Bi atoms. This leads to Bi-Bi interactions in a random alloy broadening these states in energy and causing the band-gap narrowing.

Central polydactyly of the foot: surgical management with plantar and dorsal advancement flaps.

PubMed

Osborn, Emily J; Davids, Jon R; Leffler, Lauren C; Gibson, Thomas W; Pugh, Linda I

2014-01-01

Central polydactyly is the least common form of foot polydactyly, and the intercalary location of the duplicated ray makes the surgical exposure, excision, and closure more complex. For these reasons there is little consensus concerning the optimal technique for surgical management. A retrospective case series of 22 patients with 27 feet with central polydactyly, treated surgically by the dorsal and plantar advancement flap technique, was performed. Change in width of the forefoot was measured from radiographs by the metatarsal gap ratio. Functional outcomes were assessed by the Foot and Ankle Ability Measure. Signficant narrowing of the forefoot, as measured radiographically by the metatarsal gap ratio, was achieved after surgery (P<0.0001). This radiographic narrowing was maintained with growth after a mean follow-up of 8 years (P=0.0001). In 7 of the unilateral cases, the mean forefoot radiographic width of the affected side, after surgical resection and reconstruction of the central polydactyly, was 2% greater than the contralateral, uninvolved side. Persistent clinical widening of the forefoot after surgery was reported in the majority (82%) of cases. The Foot and Ankle Ability Measure results showed near-normal functional outcomes in itemized activities of daily living, itemized sports, and overall function categories. The few reports of less than normal foot function were related to shoe wear issues and incisional scarring that was painful or cosmetically unappealing. The radiographic and functional outcomes after surgical management of central polydactyly with the dorsal and plantar advancement flap technique are excellent. The technique successfully narrows the forefoot on radiographs, and this narrowing is maintained with growth over time. However, families should be advised that persistent perceived widening of the forefoot relative to normal is common, despite successful radiographic narrowing after surgery. IV.

2. Photocopied July 1971 from photostat Jordan Narrows Folder #1, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Photocopied July 1971 from photostat Jordan Narrows Folder #1, Engineering Department, Utah Power and Light Co., Salt Lake City, Utah. JORDAN NARROWS STATION. PLAN AND SECTION. - Salt Lake City Water & Electrical Power Company, Jordan Narrows Hydroelectric Plant, Jordan River, Riverton, Salt Lake County, UT

Detecting tree-fall gap disturbances in tropical rain forests with airborne lidar

NASA Astrophysics Data System (ADS)

Espirito-Santo, F. D. B.; Saatchi, S.; Keller, M.

2017-12-01

Forest inventory studies in the Amazon indicate a large terrestrial carbon sink. However, field plots may fail to represent forest mortality processes at landscape-scales of tropical forests. Here we characterize the frequency distribution of tree-fall gap disturbances in natural forests of tropical forests using a novel combination of forest inventory and airborne lidar data. We quantify gap size frequency distribution along vertical and horizontal dimensions in ten Neotropical forest canopies distributed across gradients of climate and landscapes using airborne lidar measurements. We assessed all canopy openings related to each class of tree height which yields a three dimensional structure of the distribution of canopy gaps. Gap frequency distributions from lidar CHM data vary markedly with minimum gap size thresholds, but we found that natural forest disturbances (tree-fall gaps) follow a power-law distribution with narrow range of power-law exponents (-1.2 to -1.3). These power-law exponents from gap frequency distributions provide insights into how natural forest disturbances are distributed over tropical forest landscape.

[The changing gaps of life expectancy on genders in urban cities of China, from 2005 to 2010].

PubMed

Shen, Jie; Jiang, Qing-wu

2013-07-01

To analyze the gender difference of life expectancy in urban people of China and to explore both age-specific and cause-specific contributions to the changing differences in life expectancy on genders. Data on life expectancy (male and female) and mortality were obtained from the"Annual Statistics of public health in China". Male-female gender difference was analyzed by decomposition methodologies, including age-specific decomposition and the cause-specific decomposition. Women had lived much longer than men in the Chinese urban citizens, with remarkable gains in life expectancy since 2005. Difference in gender reached a peak in 2007, with the gap of 5.3 years. Differences on mortality between men and women in the 60-79 age groups made the largest contribution (42%-47%) to the gap of 6 years on life expectancy in genders. With the widening of the gaps in gender on life expectancy between 2005 and 2007, faster declining of mortality among groups of women in age 0-1 age and over 75 years old groups made the largest contributions. Between 2007 and 2008, along with the reduction of gaps in gender, all the age groups except the 1-15 and 50-55 year-olds showed negative efforts. In 2009-2010, the widening gaps in gender on life expectancy were caused by the positive effect in the 60-70 age group. Among all the causes of death, cancer (1.638-2.019 years), circulatory diseases (1.271-1.606 years), respiratory diseases (0.551-0.800 years) made the largest contributions to the gender gap. 33%-38% of the gaps in gender were caused by cancer and among all the cancers, among which lung cancer contributed 0.6 years to the overall gap. Contribution of cancers to the gender gap was reducing, but when time went on it was mostly influenced by the narrowing effect caused by liver cancer on the gap in gender. Traffic accidents and suicidal issues were the external causes that influencing the gender gap and contributing 10.60%-15.78% to the overall differentials. Public health efforts in reducing the excess mortalities for cancer, circulatory and respiratory diseases, suicide, among men in particular, will further narrow the gender gap on life expectancy in the urban cities of China.

Ternary arsenides ATt{sub 3}As{sub 3} (A=K, Rb; Tt=Ge, Sn) with layered structures

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

Khatun, Mansura; Stoyko, Stanislav S.; Mar, Arthur, E-mail: arthur.mar@ualberta.ca

2016-06-15

The four ternary arsenides ATt{sub 3}As{sub 3} (A=K, Rb; Tt=Ge, Sn) were obtained by reaction of the elements at 600–650 °C. They adopt an orthorhombic structure (space group Pnma, Z=4, with cell parameters ranging from a=9.9931(11) Å, b=3.7664(4) Å, c=18.607(2) Å for KGe{sub 3}As{sub 3} to a=10.3211(11) Å, b=4.0917(4) Å, c=19.570(2) Å for RbSn{sub 3}As{sub 3}) containing corrugated [Tt{sub 3}As{sub 3}] layers built from Tt-centred trigonal pyramids and tetrahedra forming five-membered rings decorated with As handles. They can be considered to be Zintl phases with Tt atoms in +4, +3, and +1 oxidation states. Band structure calculations predict that thesemore » compounds are semiconductors with narrow band gaps (0.71 eV in KGe{sub 3}As{sub 3}, 0.50 eV in KSn{sub 3}As{sub 3}). - Graphical abstract: Ternary arsenides ATt{sub 3}As{sub 3} (A=K, Rb; Tt=Ge, Sn) contain corrugated layers with Tt atoms in three different oxidation states and are narrow band gap semiconductors. Display Omitted - Highlights: • ATt{sub 3}As{sub 3} (A=K, Rb; Tt=Ge, Sn) contains Tt atoms in three oxidation states. • The structure differs from NaGe{sub 3}P{sub 3} in terms of layer stacking arrangement. • The compounds are predicted to be narrow band gap semiconductors.« less

Dynamic film thickness between bubbles and wall in a narrow channel

NASA Astrophysics Data System (ADS)

Ito, Daisuke; Damsohn, Manuel; Prasser, Horst-Michael; Aritomi, Masanori

2011-09-01

The present paper describes a novel technique to characterize the behavior of the liquid film between gas bubbles and the wall in a narrow channel. The method is based on the electrical conductance. Two liquid film sensors are installed on both opposite walls in a narrow rectangular channel. The liquid film thickness underneath the gas bubbles is recorded by the first sensor, while the void fraction information is obtained by measuring the conductance between the pair of opposite sensors. Both measurements are taken on a large two-dimensional domain and with a high speed. This makes it possible to obtain the two-dimensional distribution of the dynamic liquid film between the bubbles and the wall. In this study, this method was applied to an air-water flow ranging from bubbly to churn regimes in the narrow channel with a gap width of 1.5 mm.

Large-scale transport across narrow gaps in rod bundles

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

Guellouz, M.S.; Tavoularis, S.

1995-09-01

Flow visualization and how-wire anemometry were used to investigate the velocity field in a rectangular channel containing a single cylindrical rod, which could be traversed on the centreplane to form gaps of different widths with the plane wall. The presence of large-scale, quasi-periodic structures in the vicinity of the gap has been demonstrated through flow visualization, spectral analysis and space-time correlation measurements. These structures are seen to exist even for relatively large gaps, at least up to W/D=1.350 (W is the sum of the rod diameter, D, and the gap width). The above measurements appear to compatible with the fieldmore » of a street of three-dimensional, counter-rotating vortices, whose detailed structure, however, remains to be determined. The convection speed and the streamwise spacing of these vortices have been determined as functions of the gap size.« less

Role of antenna modes and field enhancement in second harmonic generation from dipole nanoantennas.

PubMed

de Ceglia, Domenico; Vincenti, Maria Antonietta; De Angelis, Costantino; Locatelli, Andrea; Haus, Joseph W; Scalora, Michael

2015-01-26

We study optical second harmonic generation from metallic dipole antennas with narrow gaps. Enhancement of the fundamental-frequency field in the gap region plays a marginal role on conversion efficiency. In the symmetric configuration, i.e., with the gap located at the center of the antenna axis, reducing gap size induces a significant red-shift of the maximum conversion efficiency peak. Either enhancement or inhibition of second-harmonic emission may be observed as gap size is decreased, depending on the antenna mode excited at the harmonic frequency. The second-harmonic signal is extremely sensitive to the asymmetry introduced by gap's displacements with respect to the antenna center. In this situation, second-harmonic light can couple to all the available antenna modes. We perform a multipolar analysis that allows engineering the far-field SH emission and find that the interaction with quasi-odd-symmetry modes generates radiation patterns with a strong dipolar component.

The research-practice gap: bridging the schism between eating disorder researchers and practitioners.

PubMed

Lilienfeld, Scott O; Ritschel, Lorie A; Lynn, Steven Jay; Brown, Amanda P; Cautin, Robin L; Latzman, Robert D

2013-07-01

The field of eating disorders (EDs) treatment has been beset by a marked disjunction between scientific evidence and clinical application. We describe the nature and scope of the research-practice gap in the ED field. We draw on surveys and broader literature to better understand the research-practice gap in ED treatment and reasons for resistance to evidence-based practice. We identify three sources of the research-practice gap: (1) attitudinal factors, (2) differences in the definition of "evidence," and (3) cognitive factors, especially naïve realism and confirmation bias. We affirm the role of science as a safeguard against human fallibility and as a means of bridging the research-practice gap, and delineate key principles of scientific thinking for ED researchers and practitioners. We conclude with proposals for narrowing the research-practice gap in ED treatment and enhancing the quality of interventions for ED clients. Copyright © 2013 Wiley Periodicals, Inc.

A Conserved RhoGAP Limits M-phase Contractility and Coordinates with Microtubule Asters to Restrict Active RhoA to the Cell Equator During Cytokinesis

PubMed Central

Zanin, Esther; Desai, Arshad; Poser, Ina; Toyoda, Yusuke; Andree, Cordula; Moebius, Claudia; Bickle, Marc; Conradt, Barbara; Piekny, Alisa; Oegema, Karen

2014-01-01

SUMMARY During animal cell cytokinesis, the spindle directs contractile ring assembly by activating RhoA in a narrow equatorial zone. Rapid GTPase activating protein (GAP)-mediated inactivation (RhoA flux) is proposed to limit RhoA zone dimensions. Testing the significance of RhoA flux has been hampered by the fact that the GAP targeting RhoA is not known. Here, we identify M-phase GAP (MP-GAP) as the primary GAP targeting RhoA during mitosis/cytokinesis. MP-GAP inhibition caused excessive RhoA activation in M-phase leading to the uncontrolled formation of large cortical protrusions and late cytokinesis failure. RhoA zone width was broadened by attenuation of the centrosomal asters but was not affected by MP-GAP inhibition alone. Simultaneous aster attenuation and MP-GAP inhibition led to RhoA accumulation around the entire cell periphery. These results identify the major GAP restraining RhoA during cell division and delineate the relative contributions of RhoA flux and centrosomal asters in controlling RhoA zone dimensions. PMID:24012485

Making Moves: Formative Assessment in Mathematics

ERIC Educational Resources Information Center

Duckor, Brent; Holmberg, Carrie; Becker, Joanne Rossi

2017-01-01

Research on teacher professional learning has shown that formative assessment can improve student learning more than most instructional practices. Empirical evidence indicates that thoughtfully implemented formative assessment practices improve students' learning, increase students' scores, and narrow achievement gaps between low-achieving…

Narrowing the Gap between Theory and Practice: Proposals for a Fifth Generation of Community Colleges.

ERIC Educational Resources Information Center

Deegan, William L.; Tillery, Dale

1986-01-01

The "fifth generation" of community colleges must assess and resolve fundamental questions of quality and productivity. A research agenda is outlined that addresses mission, delivery systems, student needs, and attendance patterns. (LB)

Changing Patterns of Nonprior Service Attrition in the Army National Guard and Army Reserve

DTIC Science & Technology

1988-07-01

attrition risk is gender . Women are at much higher risk of attrition than males with similar characteristics. However, the gap between male and... gender (Table 5.1). Women are at much higher risk of attrition than similar males. However, the gap between male and female attrition narrows...the basis of gender , educational achievement, aptitude scores, race, and age. 1Vi" The characteristic that makes the largest consistent difference in

Examining the Perceptions of Gwinnett and Cobb County Georgia Principals to Determine the Strategies Needed to Improve Performance and Graduation Rates of African-American Males in Metropolitan U.S. Schools

ERIC Educational Resources Information Center

Henderson, Darren L.

2012-01-01

The purpose of this study was to examine the perceptions of high school administrators in Gwinnett and Cobb Counties, Georgia that have successfully narrowed the achievement gap for high school African-American males as to: (a) why the achievement gap continues to occur in other metropolitan high schools in the United States; (b) what successful…

Self-Interaction Corrected Electronic Structure and Energy Gap of CuAlO2 beyond Local Density Approximation

NASA Astrophysics Data System (ADS)

Nakanishi, Akitaka

2011-05-01

We implemented a self-interaction correction (SIC) into first-principles calculation code to go beyond local density approximation and applied it to CuAlO2. Our simulation shows that the valence band width calculated within the SIC is narrower than that calculated without the SIC because the SIC makes the d-band potential deeper. The energy gap calculated within the SIC expands and is close to experimental data.

The role of hydrogenated amorphous silicon oxide buffer layer on improving the performance of hydrogenated amorphous silicon germanium single-junction solar cells

NASA Astrophysics Data System (ADS)

Sritharathikhun, Jaran; Inthisang, Sorapong; Krajangsang, Taweewat; Krudtad, Patipan; Jaroensathainchok, Suttinan; Hongsingtong, Aswin; Limmanee, Amornrat; Sriprapha, Kobsak

2016-12-01

Hydrogenated amorphous silicon oxide (a-Si1-xOx:H) film was used as a buffer layer at the p-layer (μc-Si1-xOx:H)/i-layer (a-Si1-xGex:H) interface for a narrow band gap hydrogenated amorphous silicon germanium (a-Si1-xGex:H) single-junction solar cell. The a-Si1-xOx:H film was deposited by plasma enhanced chemical vapor deposition (PECVD) at 40 MHz in a same processing chamber as depositing the p-type layer. An optimization of the thickness of the a-Si1-xOx:H buffer layer and the CO2/SiH4 ratio was performed in the fabrication of the a-Si1-xGex:H single junction solar cells. By using the wide band gap a-Si1-xOx:H buffer layer with optimum thickness and CO2/SiH4 ratio, the solar cells showed an improvement in the open-circuit voltage (Voc), fill factor (FF), and short circuit current density (Jsc), compared with the solar cells fabricated using the conventional a-Si:H buffer layer. The experimental results indicated the excellent potential of the wide-gap a-Si1-xOx:H buffer layers for narrow band gap a-Si1-xGex:H single junction solar cells.

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

Exact-solution for cone-plate viscometry

NASA Astrophysics Data System (ADS)

Giacomin, A. J.; Gilbert, P. H.

2017-11-01

The viscosity of a Newtonian fluid is often measured by confining the fluid to the gap between a rotating cone that is perpendicular to a fixed disk. We call this experiment cone-plate viscometry. When the cone angle approaches π/2 , the viscometer gap is called narrow. The shear stress in the fluid, throughout a narrow gap, hardly departs from the shear stress exerted on the plate, and we thus call cone-plate flow nearly homogeneous. In this paper, we derive an exact solution for this slight heterogeneity, and from this, we derive the correction factors for the shear rate on the cone and plate, for the torque, and thus, for the measured Newtonian viscosity. These factors thus allow the cone-plate viscometer to be used more accurately, and with cone-angles well below π/2 . We find cone-plate flow field heterogeneity to be far slighter than previously thought. We next use our exact solution for the velocity to arrive at the exact solution for the temperature rise, due to viscous dissipation, in cone-plate flow subject to isothermal boundaries. Since Newtonian viscosity is a strong function of temperature, we expect our new exact solution for the temperature rise be useful to those measuring Newtonian viscosity, and especially so, to those using wide gaps. We include two worked examples to teach practitioners how to use our main results.

Hinge Moments of Sealed-Internal-Balance Arrangements for Control Surfaces I : Theoretical Investigation

NASA Technical Reports Server (NTRS)

Murray, Harry E.; Erwin, Mary A.

1945-01-01

The results of a theoretical analysis of the hinge-moment characteristics of various sealed-internal-balance arrangements for control surfaces are presented. The analysis considered overhands sealed to various types of wing structure by flexible seals spanning gaps of various widths or sealed to the wing structure by a flexible system of linked plates. Leakage was not considered; the seal was assumed to extend the full spanwise length of the control surface. The effect of the developed width of the flexible seal and of the geometry of the structure to which the seal was anchored was investigated, as well as the effect of the gap width that is sealed. The results of the investigation indicated that the most nearly linear control-surface hinge-moment characteristics can probably be obtained from a flexible seal over a narrow gap (about 0.1 of the overhang chord), which is so installed that the motion of the seal is restricted to a region behind the point of attachment of the seal to the wing structure. Control-surface hinge moments that tend to be high at large deflections and low or overbalanced at small deflections will result if a very narrow seal is used.

Birth cohort and the specialization gap between same-sex and different-sex couples.

PubMed

Giddings, Lisa; Nunley, John M; Schneebaum, Alyssa; Zietz, Joachim

2014-04-01

We examine differences in household specialization between same-sex and different-sex couples within and across three birth cohorts: Baby Boomers, Generation X, and Generation Y. Using three measures of household specialization, we find that same-sex couples are less likely than their different-sex counterparts to exhibit a high degree of specialization. However, the "specialization gap" between same-sex and different-sex couples narrows across birth cohorts. These findings are indicative of a cohort effect. Our results are largely robust to the inclusion of a control for the presence of children and for subsets of couples with and without children. We provide three potential explanations for why the specialization gap narrows across cohorts. First, different-sex couples from more recent birth cohorts may have become more like same-sex couples in terms of household specialization. Second, social and legal changes may have prompted a greater degree of specialization within same-sex couples relative to different-sex couples. Last, the advent of reproductive technologies, which made having children easier for same-sex couples from more recent birth cohorts, could result in more specialization in such couples relative to different-sex couples.

Optical conductivity calculation of a k.p model semiconductor GaAs incorporating first-order electron-hole vertex correction

NASA Astrophysics Data System (ADS)

Nurhuda, Maryam; Aziz Majidi, Muhammad

2018-04-01

The role of excitons in semiconducting materials carries potential applications. Experimental results show that excitonic signals also appear in optical absorption spectra of semiconductor system with narrow gap, such as Gallium Arsenide (GaAs). While on the theoretical side, calculation of optical spectra based purely on Density Functional Theory (DFT) without taking electron-hole (e-h) interactions into account does not lead to the appearance of any excitonic signal. Meanwhile, existing DFT-based algorithms that include a full vertex correction through Bethe-Salpeter equation may reveal an excitonic signal, but the algorithm has not provided a way to analyze the excitonic signal further. Motivated to provide a way to isolate the excitonic effect in the optical response theoretically, we develop a method of calculation for the optical conductivity of a narrow band-gap semiconductor GaAs within the 8-band k.p model that includes electron-hole interactions through first-order electron-hole vertex correction. Our calculation confirms that the first-order e-h vertex correction reveals excitonic signal around 1.5 eV (the band gap edge), consistent with the experimental data.

Size Effects in Dye-Sensitized TiO2 Clusters

NASA Astrophysics Data System (ADS)

Marom, Noa; Körzdörfer, Thomas; Ren, Xinguo; Tkatchenko, Alexandre; Chelikowsky, James

2014-03-01

The development of solar cells is driven by the need for clean and sustainable energy. Organic and dye sensitized cells are considered as promising technologies, particularly for large area, low cost applications. However, the efficiency of such cells is still far from the theoretical limit. Ab initio simulations may be used for computer-aided design of new materials and nano-structures for more efficient solar cells. It is essential to obtain an accurate description of the electronic structure, including the fundamental gaps and energy level alignment at the interfaces in the device active region. This requires going beyond ground-state DFT to the GW approximation. A recently developed GW method [PRB 86, 041110R (2012)] is applied to dye-sensitized TiO2 clusters [PRB 84, 245115 (2011)]. The effect of cluster size on the energy level alignment at the dye-TiO2 interface is discussed. With the increase in the TiO2 cluster size its gap narrows. The gap of the molecule attached to the cluster subsequently narrows due to screening. As a result, the energy level alignment at the interface changes in an unexpected way [Marom, Körzdörfer, Ren, Tkatchenko, Chelikowsky, to be published].

Gap-state engineering of visible-light-active ferroelectrics for photovoltaic applications.

PubMed

Matsuo, Hiroki; Noguchi, Yuji; Miyayama, Masaru

2017-08-08

Photoferroelectrics offer unique opportunities to explore light energy conversion based on their polarization-driven carrier separation and above-bandgap voltages. The problem associated with the wide bandgap of ferroelectric oxides, i.e., the vanishingly small photoresponse under visible light, has been overcome partly by bandgap tuning, but the narrowing of the bandgap is, in principle, accompanied by a substantial loss of ferroelectric polarization. In this article, we report an approach, 'gap-state' engineering, to produce photoferroelectrics, in which defect states within the bandgap act as a scaffold for photogeneration. Our first-principles calculations and single-domain thin-film experiments of BiFeO 3 demonstrate that gap states half-filled with electrons can enhance not only photocurrents but also photovoltages over a broad photon-energy range that is different from intermediate bands in present semiconductor-based solar cells. Our approach opens a promising route to the material design of visible-light-active ferroelectrics without sacrificing spontaneous polarization.Overcoming the optical transparency of wide bandgap of ferroelectric oxides by narrowing its bandgap tends to result in a loss of polarization. By utilizing defect states within the bandgap, Matsuo et al. report visible-light-active ferroelectrics without sacrificing polarization.

Conceptual design of a 0.1 W magnetic refrigerator for operation between 10 K and 2 K

NASA Technical Reports Server (NTRS)

Helvensteijn, Ben P. M.; Kashani, Ali

1990-01-01

The design of a magnetic refrigerator for space applications is discussed. The refrigerator is to operate in the temperature range of 10 K-2 K, at a 2 K cooling power of 0.10 W. As in other magnetic refrigerators operating in this temperature range GGG has been selected as the refrigerant. Crucial to the design of the magnetic refrigerator are the heat switches at both the hot and cold ends of the GGG pill. The 2 K heat switch utilizes a narrow He II filled gap. The 10 K heat switch is based on a narrow helium gas gap. For each switch, the helium in the gap is cycled by means of activated carbon pumps. The design concentrates on reducing the switching times of the pumps and the switches as a whole. A single stage system (one magnet; one refrigerant pill) is being developed. Continuous cooling requires the fully stationary system to have at least two stages running parallel/out of phase with each other. In order to conserve energy, it is intended to recycle the magnetic energy between the magnets. To this purpose, converter networks designed for superconducting magnetic energy storage are being studied.

Thermoelectricity in correlated narrow-gap semiconductors

NASA Astrophysics Data System (ADS)

Tomczak, Jan M.

2018-05-01

We review many-body effects, their microscopic origin, as well as their impact on thermoelectricity in correlated narrow-gap semiconductors. Members of this class—such as FeSi and FeSb2—display an unusual temperature dependence in various observables: insulating with large thermopowers at low temperatures, they turn bad metals at temperatures much smaller than the size of their gaps. This insulator-to-metal crossover is accompanied by spectral weight-transfers over large energies in the optical conductivity and by a gradual transition from activated to Curie–Weiss-like behaviour in the magnetic susceptibility. We show a retrospective of the understanding of these phenomena, discuss the relation to heavy-fermion Kondo insulators—such as Ce3Bi4Pt3 for which we present new results—and propose a general classification of paramagnetic insulators. From the latter, FeSi emerges as an orbital-selective Kondo insulator. Focussing on intermetallics such as silicides, antimonides, skutterudites, and Heusler compounds we showcase successes and challenges for the realistic simulation of transport properties in the presence of electronic correlations. Further, we explore new avenues in which electronic correlations may contribute to the improvement of thermoelectric performance.

Improved Reproductive Health Equity Between the Poor and the Rich: An Analysis of Trends in 46 Low- and Middle-Income Countries.

PubMed

Ross, John

2015-09-07

While several indicators for reproductive health have improved for entire populations, few analyses are available for trends over time in the gaps between the poor and the rich. This paper tracks improvements in the equitable distribution of reproductive health indicators according to wealth quintiles, especially for contraceptive use, in 46 low- and middle-income countries based on national population-based surveys conducted between 1990 and 2013. It focuses on the gaps between the poorest and richest quintiles in the earliest and latest survey rounds across a number of reproductive health indicators related to family planning, fertility desires, antenatal care, and infant and child mortality, as well as on improvements in the absolute levels of contraceptive use by the poorest quintile. Gap changes were decomposed to show how the gaps can either diminish or grow due to either the bottom or top quintile, or both. In addition, bivariate correlation analysis was conducted to examine the relationship of the gaps, and of contraceptive use by the poor, to national family planning program efforts. Overall, the gaps between the poorest and richest have narrowed, due primarily to faster improvements among the poor than the rich. For example, the gap between the richest and poorest in the modern contraceptive prevalence rate has declined by 25%, from a 20.4 percentage point difference to a 15.4 point difference. And the gap has decreased more where family planning programs have been stronger. Across most of 18 other reproductive health indicators, the gaps have also been narrowing. For instance, the poor-rich gap for antenatal care decreased by over a third, from a difference of 30.7 percentage points to 19.6 percentage points. Gaps in infant and child mortality also have declined by about one-third. The pattern for contraceptive use in sub-Saharan Africa, however, has been mixed, with the gap actually increasing in some countries with strong programs. This disparity may largely reflect that family planning in the region is generally at an earlier stage in its history, and so programs may initially be reaching better-off clients, especially in urban areas. To promote additional equity, programs should emphasize efforts to increase access to voluntary family planning services to the least well-off, including those in rural and peri-urban areas. © Ross.

Improved Reproductive Health Equity Between the Poor and the Rich: An Analysis of Trends in 46 Low- and Middle-Income Countries

PubMed Central

2015-01-01

While several indicators for reproductive health have improved for entire populations, few analyses are available for trends over time in the gaps between the poor and the rich. This paper tracks improvements in the equitable distribution of reproductive health indicators according to wealth quintiles, especially for contraceptive use, in 46 low- and middle-income countries based on national population-based surveys conducted between 1990 and 2013. It focuses on the gaps between the poorest and richest quintiles in the earliest and latest survey rounds across a number of reproductive health indicators related to family planning, fertility desires, antenatal care, and infant and child mortality, as well as on improvements in the absolute levels of contraceptive use by the poorest quintile. Gap changes were decomposed to show how the gaps can either diminish or grow due to either the bottom or top quintile, or both. In addition, bivariate correlation analysis was conducted to examine the relationship of the gaps, and of contraceptive use by the poor, to national family planning program efforts. Overall, the gaps between the poorest and richest have narrowed, due primarily to faster improvements among the poor than the rich. For example, the gap between the richest and poorest in the modern contraceptive prevalence rate has declined by 25%, from a 20.4 percentage point difference to a 15.4 point difference. And the gap has decreased more where family planning programs have been stronger. Across most of 18 other reproductive health indicators, the gaps have also been narrowing. For instance, the poor-rich gap for antenatal care decreased by over a third, from a difference of 30.7 percentage points to 19.6 percentage points. Gaps in infant and child mortality also have declined by about one-third. The pattern for contraceptive use in sub-Saharan Africa, however, has been mixed, with the gap actually increasing in some countries with strong programs. This disparity may largely reflect that family planning in the region is generally at an earlier stage in its history, and so programs may initially be reaching better-off clients, especially in urban areas. To promote additional equity, programs should emphasize efforts to increase access to voluntary family planning services to the least well-off, including those in rural and peri-urban areas. PMID:26374803

Airway mechanics and methods used to visualize smooth muscle dynamics in vitro.

PubMed

Cooper, P R; McParland, B E; Mitchell, H W; Noble, P B; Politi, A Z; Ressmeyer, A R; West, A R

2009-10-01

Contraction of airway smooth muscle (ASM) is regulated by the physiological, structural and mechanical environment in the lung. We review two in vitro techniques, lung slices and airway segment preparations, that enable in situ ASM contraction and airway narrowing to be visualized. Lung slices and airway segment approaches bridge a gap between cell culture and isolated ASM, and whole animal studies. Imaging techniques enable key upstream events involved in airway narrowing, such as ASM cell signalling and structural and mechanical events impinging on ASM, to be investigated.

Imaging a Central Ionized Component, a Narrow Ring, and the CO Snowline in the Multigapped Disk of HD 169142

NASA Astrophysics Data System (ADS)

Macías, Enrique; Anglada, Guillem; Osorio, Mayra; Torrelles, José M.; Carrasco-González, Carlos; Gómez, José F.; Rodríguez, Luis F.; Sierra, Anibal

2017-04-01

We report Very Large Array observations at 7 mm, 9 mm, and 3 cm toward the pre-transitional disk of the Herbig Ae star HD 169142. These observations have allowed us to study the millimeter emission of this disk with the highest angular resolution so far (0.″12 × 0.″09, or 14 au × 11 au, at 7 mm). Our 7 and 9 mm images show a narrow ring of emission at a radius of ˜25 au tracing the outer edge of the inner gap. This ring presents an asymmetric morphology that could be produced by dynamical interactions between the disk and forming planets. Additionally, the azimuthally averaged radial intensity profiles of the 7 and 9 mm images confirm the presence of the previously reported gap at ˜45 au and reveal a new gap at ˜85 au. We analyzed archival DCO+(3-2) and C18O(2-1) ALMA observations, showing that the CO snowline is located very close to this third outer gap. This suggests that growth and accumulation of large dust grains close to the CO snowline could be the mechanism responsible for this proposed outer gap. Finally, a compact source of emission is detected at 7 mm, 9 mm, and 3 cm toward the center of the disk. Its flux density and spectral index indicate that it is dominated by free-free emission from ionized gas, which could be associated with the photoionization of the inner disk, an independent object, or an ionized jet.

Direct Observation of the Evolution of Both the HOMO and LUMO Energy Levels of a Silole Derivative at a Magnesium/Silole Interface

DTIC Science & Technology

2004-01-01

transport gap has been observed in K-intercalated Alq3 films, where the HOMO - Proc. of SPIE Vol. 5214 371 LUMO on-set separation is 3.05 ± 0.1 eV...while in a neat Alq3 film, the transport gap is 3.9 ± 0.4 eV. 22,25 Narrowing of the transport gap of alkali-fulleride films (K3C60, K6C60) has also...Rajagopal and A. Kahn, “Photoemission spectroscopy investigation of magnesium– Alq3 interfaces“, J. Appl. Phys. 84, pp. 355-358, 1998. 9 M. G. Mason

Rotating electric machine with fluid supported parts

DOEpatents

Smith, Jr., Joseph L.; Kirtley, Jr., James L.

1981-01-01

A rotating electric machine in which the armature winding thereof and other parts are supported by a liquid to withstand the mechanical stresses applied during transient overloads and the like. In particular, a narrow gap is provided between the armature winding and the stator which supports it and this gap is filled with an externally pressurized viscous liquid. The liquid is externally pressurized sufficiently to balance the static loads on the armature winding. Transient mechanical loads which deform the armature winding alter the gap dimensions and thereby additionally pressurize the viscous liquid to oppose the armature winding deformation and more nearly uniformly to distribute the resulting mechanical stresses.

Bridging the gap between theories of sensory cue integration and the physiology of multisensory neurons

PubMed Central

Fetsch, Christopher R.

2013-01-01

The richness of perceptual experience, as well as its usefulness for guiding behavior, depends upon the synthesis of information across multiple senses. Recent decades have witnessed a surge in our understanding of how the brain combines sensory signals, or cues. Much of this research has been guided by one of two distinct approaches, one driven primarily by neurophysiological observations, the other guided by principles of mathematical psychology and psychophysics. Conflicting results and interpretations have contributed to a conceptual gap between psychophysical and physiological accounts of cue integration, but recent studies of visual-vestibular cue integration have narrowed this gap considerably. PMID:23686172

Assessment of atherosclerotic luminal narrowing of coronary arteries based on morphometrically generated visual guides.

PubMed

Barth, Rolf F; Kellough, David A; Allenby, Patricia; Blower, Luke E; Hammond, Scott H; Allenby, Greg M; Buja, L Maximilian

Determination of the degree of stenosis of atherosclerotic coronary arteries is an important part of postmortem examination of the heart, but, unfortunately, estimation of the degree of luminal narrowing can be imprecise and tends to be approximations. Visual guides can be useful to assess this, but earlier attempts to develop such guides did not employ digital technology. Using this approach, we have developed two computer-generated morphometric guides to estimate the degree of luminal narrowing of atherosclerotic coronary arteries. The first is based on symmetric or eccentric circular or crescentic narrowing of the vessel lumen and the second on either slit-like or irregularly shaped narrowing of the vessel lumens. Using the Aperio ScanScope XT at a magnification of 20× we created digital whole-slide images of 20 representative microscopic cross sections of the left anterior descending (LAD) coronary artery, stained with either hematoxylin and eosin (H&E) or Movat's pentachrome stain. These cross sections illustrated a variety of luminal profiles and degrees of stenosis. Three representative types of images were selected and a visual guide was constructed with Adobe Photoshop CS5. Using the "Scale" and "Measurement" tools, we created a series of representations of stenosis with luminal cross sections depicting 20%, 40%, 60%, 70%, 80%, and 90% occlusion of the LAD branch. Four pathologists independently reviewed and scored the degree of atherosclerotic luminal narrowing based on our visual guides. In addition, digital technology was employed to determine the degree of narrowing by measuring the cross-sectional area of the 20 microscopic sections of the vessels, first assuming no narrowing and then comparing this to the percent of narrowing determined by precise measurement. Two of the observers were very experienced general autopsy pathologists, one was a first-year pathology resident on his first rotation on the autopsy service, and the fourth observer was a highly experienced cardiovascular pathologist. Interobserver reliability was assessed by determination of the intraclass correlation coefficient. The degrees of agreement for two H&E- and Movat-stained sections of the LADs from each of 10 decedents were 0.874 and 0.899, respectively, indicating strong interobserver agreement. On the average, the mean visual scores were ~8% less than the morphometric assessment (52.7 vs. 60.2), respectively. The visual guides that we have generated for scoring atherosclerotic luminal narrowing of coronary arteries should be helpful for a broad group of pathologists, from beginning pathology residents to experienced cardiovascular pathologists. Copyright © 2017 Elsevier Inc. All rights reserved.

Health Equilibrium Initiative: a public health intervention to narrow the health gap and promote a healthy weight in Swedish children.

PubMed

Magnusson, Maria; Hallmyr Lewis, Moa; Smaga-Blom, Malgorzata; Lissner, Lauren; Pickering, Chris

2014-07-29

Inequity in health is a global concern. Even in Sweden there are considerable health gaps between different social groups, not least concerning life-style related conditions. Interventions drawing on Community-based participatory research (CBPR) have potential to build prerequisites for complex, supportive structures that constitute basis for implementation of sustainable health promoting programs. CBPR rests on principles of empowerment. The researchers are responsible for the scientific quality and that ethical standards are met. Health Equilibrium Initiative (HEI) aims at narrowing the health gap and promoting healthy weight in children; "healthy weight" including both anthropometric criteria and aspects having to do with self-esteem and self-efficacy. Evaluation objectives are to compare outcome between children in intervention and control areas, conduct health economic assessments (HEA) and evaluate the processes of the project. HEI is a repeated cross-sectional and longitudinal study. The Program Logic Model is based on Social Cognitive Theory and Intervention Mapping. Primary contact groups are children in disadvantaged communities. Core efforts are to confirm and convey knowledge, elucidate and facilitate on-going health work and support implementation of continuous health work. Socioeconomic status is assessed on area level by the parameters yearly average income, degree of employment, tertiary education and percent of inhabitants born in countries where violent conflicts recently have taken place or were ongoing. Anthropometry, food patterns, physical activity and belief in ability to affect health; together with learning, memory and attention assessment will be assessed in 350 children (born 2006). Examinations will be repeated after two years, forming the basis of a health economic analysis. The process evaluation procedure will use document analysis (such as structured reports from meetings and dialogues, school/workplaces policies and curriculum, food service menus); key informant interviews and focus groups with parents, children and professionals. Inviting, awaiting and including local perspectives create mutual confidence and collaboration. Enhanced self-efficacy and access to relevant knowledge has potential to enable individuals and communities to choose alternatives that are relevant for their health and well-being in a long perspective. The economic of this study may contribute in decision- making processes regarding appropriate public health interventions.

An economic analysis of life expectancy by gender with application to the United States.

PubMed

Leung, Michael C M; Zhang, Jie; Zhang, Junsen

2004-07-01

This paper presents an economic model to explain the behavior of life expectancy of both sexes. It explicitly examines the relationship between the gender gap in life expectancy and the gender gap in pay. It shows that as the latter narrows over the course of economic development, the former may initially expand but will eventually shrink. Simulation results from our model accord with the behavior of life expectancy for both sexes since the 1940s in the United States.

A 35-year analysis of sex differences in neurology authorship.

PubMed

Pakpoor, Jina; Liu, Li; Yousem, David

2018-03-06

Career progression in academic medicine is partly influenced by publication productivity. There has been a significant increase in female authorship over a 35-year time period at both the first and senior authorship positions in 3 high impact factor neurology journals in the United States. While these trends are encouraging, a sex gap remains. Institutions/departments may wish to consider further strategies for trainees and faculty that can help to maintain momentum and narrow the gap further. © 2018 American Academy of Neurology.

Discrete Electronic Bands in Semiconductors and Insulators: Potential High-Light-Yield Scintillators

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

Shi, Hongliang; Du, Mao-Hua

Bulk semiconductors and insulators typically have continuous valence and conduction bands. In this paper, we show that valence and conduction bands of a multinary semiconductor or insulator can be split to narrow discrete bands separated by large energy gaps. This unique electronic structure is demonstrated by first-principles calculations in several quaternary elpasolite compounds, i.e., Cs 2NaInBr 6, Cs 2NaBiCl 6, and Tl 2NaBiCl 6. The narrow discrete band structure in these quaternary elpasolites is due to the large electronegativity difference among cations and the large nearest-neighbor distances in cation sublattices. We further use Cs 2NaInBr 6 as an example tomore » show that the narrow bands can stabilize self-trapped and dopant-bound excitons (in which both the electron and the hole are strongly localized in static positions on adjacent sites) and promote strong exciton emission at room temperature. The discrete band structure should further suppress thermalization of hot carriers and may lead to enhanced impact ionization, which is usually considered inefficient in bulk semiconductors and insulators. Finally, these characteristics can enable efficient room-temperature light emission in low-gap scintillators and may overcome the light-yield bottleneck in current scintillator research.« less

Discrete Electronic Bands in Semiconductors and Insulators: Potential High-Light-Yield Scintillators

DOE PAGES

Shi, Hongliang; Du, Mao-Hua

2015-05-12

Bulk semiconductors and insulators typically have continuous valence and conduction bands. In this paper, we show that valence and conduction bands of a multinary semiconductor or insulator can be split to narrow discrete bands separated by large energy gaps. This unique electronic structure is demonstrated by first-principles calculations in several quaternary elpasolite compounds, i.e., Cs 2NaInBr 6, Cs 2NaBiCl 6, and Tl 2NaBiCl 6. The narrow discrete band structure in these quaternary elpasolites is due to the large electronegativity difference among cations and the large nearest-neighbor distances in cation sublattices. We further use Cs 2NaInBr 6 as an example tomore » show that the narrow bands can stabilize self-trapped and dopant-bound excitons (in which both the electron and the hole are strongly localized in static positions on adjacent sites) and promote strong exciton emission at room temperature. The discrete band structure should further suppress thermalization of hot carriers and may lead to enhanced impact ionization, which is usually considered inefficient in bulk semiconductors and insulators. Finally, these characteristics can enable efficient room-temperature light emission in low-gap scintillators and may overcome the light-yield bottleneck in current scintillator research.« less

Narrowing the Gap between Research and Practice. Special Edition.

ERIC Educational Resources Information Center

Wilson, Richard, Ed.

1989-01-01

This monograph summarizes recent research on the education of learning disabled students. After an introduction by the editor, individual articles include: "Teaching Listening Skills" (Linda Higbee Mandlebaum and Richard Wilson); "Study-Skills Instruction for Students with Learning Disabilities" (Deborah Gartland);…

The contribution of the polio eradication initiative to narrowing the gaps in the health workforce in the African Region.

PubMed

Kamso, Jean; Mvika, Eddy S; Ota, M O C; Okeibunor, Joseph; Mkanda, Pascal; Mihigo, Richard

2016-10-10

The Global Polio Eradication Initiative (GPEI) massively invested to overcome the crippling disease in countries of the WHO African Region. In the context of economic crisis, almost all countries in the Region lack an adequate health workforce. Large amounts were invested by GPEI in human resources. This paper shows how the human resources funded by polio contributed to narrowing the gaps in health workforce and helped strengthening and supporting other priority health programmes in Angola, Chad, DRC, Nigeria, Tanzania, and Togo. The health workforce strengthening methods used in the five different countries included the following: policy development and strategic planning, microplanning, capacity building of public health and community workers, implementation and services, monitoring and evaluation, advocacy and social mobilization, and programme review. Staff funded by polio helped with achieving good coverage in vitamin A and insecticide-treated mosquito nets (Angola, Chad); improvement of EPI and integrated disease surveillance indicators, improved quality of data (all five countries), administrative support, smooth introduction of new vaccines, increased case detection, and early isolation of patients suffering from the Guinea worm (Chad); reduction of cholera, extension of directly observed TB short course treatment (Democratic Republic of Congo); significant staff performance improvement (Nigeria). GPEI investment achieved far beyond its primary goal, and contributed to narrowing the gaps in the health workforce in countries of the African Region, as demonstrated by the best practice documentation exercise. We recommend that expertise and experience of polio funded staff should be leveraged to strengthen, expand and support other public health programmes. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Investigation on microstructure and properties of narrow-gap laser welding on reduced activation ferritic/martensitic steel CLF-1 with a thickness of 35 mm

NASA Astrophysics Data System (ADS)

Wu, Shikai; Zhang, Jianchao; Yang, Jiaoxi; Lu, Junxia; Liao, Hongbin; Wang, Xiaoyu

2018-05-01

Reduced activation ferritic martensitic (RAFM) steel is chosen as a structural material for test blanket modules (TBMs) to be constructed in International Thermonuclear Experimental Reactor (ITER) and China Fusion Engineering Test Reactor (CFETR). Chinese specific RAFM steel named with CLF-1 has been developed for CFETR. In this paper, a narrow-gap groove laser multi-pass welding of CLF-1 steel with thickness of 35 mm is conduced by YLS-15000 fiber laser. Further, the microstructures of different regions in the weld joint were characterized, and tensile impact and micro-hardness tests were carried out for evaluating the mecharical properties. The results show that the butt weld joint of CLF-1 steel with a thickness of 35 mm was well-formed using the optimal narrow-gap laser filler wire welding and no obvious defects was found such as incomplete fusion cracks and pores. The microstructures of backing layer is dominated by lath martensites and the Heat-Affected Zone (HAZ) was mainly filled with two-phase hybrid structures of secondary-tempering sorbites and martensites. The filler layer is similar to the backing layer in microstructures. In tensile tests, the tensile samples from different parts of the joint all fractured at base metal (BM). The micro-hardness of weld metal (WM) was found to be higher than that of BM and the Heat-Affected Zone (HAZ) exhibited no obvious softening. After post weld heat treatment (PWHT), it can be observed that the fusion zone of the autogenous welding bead and the upper filling beads mainly consist of lath martensites which caused the lower impact absorbing energy. The HAZ mainly included two-phase hybrid structures of secondary-tempering sorbites and martensites and exhibited favorable impact toughness.

Assessing Trends in Women’s Violence via Data Triangulation: Arrests, Convictions, Incarcerations, & Victim Reports

PubMed Central

Schwartz, Jennifer; Steffensmeier, Darrell J.; Feldmeyer, Ben

2014-01-01

Constructionist theories suggest the national rise in female violence arrests may be policy-generated because arrest statistics are produced by violent behavior and changing official responses (e.g., net-widening enforcement policies). Normative theories attribute the rise to female behavior changes (e.g., in response to increased freedoms or hardships). We examine whether any narrowing of the arrest gender gap is borne out across offense types of varying measurement reliability, in victimization data, and across two post-arrest criminal justice stages. Advanced time-series analyses over 1980–2003 support the constructionist position – first, all sources show little or no increase in women’s rates for the more reliably measured offenses of homicide and robbery, and for rape; second, the assault gender gap narrows for arrests, but holds stable in victimization data; third, the assault gender gap narrows moderately for convictions, but is stable for imprisonment, indicating spill-over effects of more expansive arrest policies. Several factors have produced greater female representation in “criminal assault” arrests including (i) proactive policing targeting and formally responding to minor violence and in private contexts, (ii) interventionist developmental epistemologies that blur distinctions among violence types and circumstances, (iii) the rise of social movements recognizing “hidden” victims, (iv) law and order political messages stressing greater accountability, and (v) the somewhat greater decline in male compared to female violence in the late 1990s. The problem of women’s violence is largely a social construction. Rather than women becoming more violent, changes in the management of violence increasingly mask differences in the violence levels of women and men. PMID:25589794

LETTER TO THE EDITOR: Green emission and bandgap narrowing due to two-photon excitation in thin film CdS formed by spray pyrolysis

NASA Astrophysics Data System (ADS)

Ullrich, B.; Schroeder, R.

2001-08-01

Thin (10 µm) film CdS on Pyrex® formed by spray pyrolysis is excited below the gap at 804 nm with 200 fs laser pulses at room temperature. Excitation intensities up to 250 GW cm-2 evoke green bandgap emission due to two-photon transitions. This two-photon photoluminescence does not show a red emission contribution in contrast to the single-photon excited emission, which is dominated by broad emission in the red spectral range. It is demonstrated that two-photon excitation causes photo-induced bandgap narrowing due to Debye screening. At 250 GW cm-2 bandgap narrowing of 47 meV is observed, which corresponds to an excited electron density of 1.6×1018 cm-3.

A k · p treatment of edge states in narrow 2D topological insulators, with standard boundary conditions for the wave function and its derivative.

PubMed

Klipstein, P C

2018-07-11

For 2D topological insulators with strong electron-hole hybridization, such as HgTe/CdTe quantum wells, the widely used 4  ×  4 k · p Hamiltonian based on the first electron and heavy hole sub-bands yields an equal number of physical and spurious solutions, for both the bulk states and the edge states. For symmetric bands and zero wave vector parallel to the sample edge, the mid-gap bulk solutions are identical to the edge solutions. In all cases, the physical edge solution is exponentially localized to the boundary and has been shown previously to satisfy standard boundary conditions for the wave function and its derivative, even in the limit of an infinite wall potential. The same treatment is now extended to the case of narrow sample widths, where for each spin direction, a gap appears in the edge state dispersions. For widths greater than 200 nm, this gap is less than half of the value reported for open boundary conditions, which are called into question because they include a spurious wave function component. The gap in the edge state dispersions is also calculated for weakly hybridized quantum wells such as InAs/GaSb/AlSb. In contrast to the strongly hybridized case, the edge states at the zone center only have pure exponential character when the bands are symmetric and when the sample has certain characteristic width values.

Sustainability of a Narrowed Achievement Gap: A Case Study

ERIC Educational Resources Information Center

Titus, Michael Richard

2010-01-01

Schools with student populations comprised predominantly of students of color, socioeconomically disadvantaged, and English Learners have traditionally been relegated to subpar educational opportunities. The accountability of the No Child Left Behind Act prodded schools to reexamine their instructional practices and implement more effective means…

76 FR 61347 - Notice of Proposed Information Collection Requests

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-04

..., middle and high schools). Total Estimated Number of Annual Responses: 413. Total Estimated Annual Burden..., middle and high schools where students achieve at high levels or where the achievement gap is narrowing... information technology. Dated: September 29, 2011. Darrin King, Director, Information Collection Clearance...

Unisex Math: Narrowing the Gender Gap.

ERIC Educational Resources Information Center

Tapia, Martha; Marsh, George E., II

This study examined gender differences in attitudes toward mathematics of undergraduate students. The Attitudes Toward Mathematics Instrument (ATMI) was administered to students enrolled in introductory mathematics classes (Pre-Calculus, Calculus, and Business Calculus) at two Southeast universities, one a large state university and the other one…

Stepwise Iterative Fourier Transform: The SIFT

NASA Technical Reports Server (NTRS)

Benignus, V. A.; Benignus, G.

1975-01-01

A program, designed specifically to study the respective effects of some common data problems on results obtained through stepwise iterative Fourier transformation of synthetic data with known waveform composition, was outlined. Included in this group were the problems of gaps in the data, different time-series lengths, periodic but nonsinusoidal waveforms, and noisy (low signal-to-noise) data. Results on sinusoidal data were also compared with results obtained on narrow band noise with similar characteristics. The findings showed that the analytic procedure under study can reliably reduce data in the nature of (1) sinusoids in noise, (2) asymmetric but periodic waves in noise, and (3) sinusoids in noise with substantial gaps in the data. The program was also able to analyze narrow-band noise well, but with increased interpretational problems. The procedure was shown to be a powerful technique for analysis of periodicities, in comparison with classical spectrum analysis techniques. However, informed use of the stepwise procedure nevertheless requires some background of knowledge concerning characteristics of the biological processes under study.

A transverse bunch by bunch feedback system for Pohang Light Source upgrade

NASA Astrophysics Data System (ADS)

Lee, E.-H.; Kim, D.-T.; Huang, J.-Y.; Shin, S.; Nakamura, T.; Kobayashi, K.

2014-12-01

The Pohang Light Source upgrade (PLS-II) project has successfully upgraded the Pohang Light Source (PLS). The main goals of the PLS-II project are to increase the beam energy to 3 GeV, increase the number of insertion devices by a factor of two (20 IDs), increase the beam current to 400 mA, and at the same time reduce the beam emittance to below 10 nm by using the existing PLS tunnel and injection system. Among 20 insertion devices, 10 narrow gap in-vacuum undulators are in operation now and two more in-vacuum undulators are to be installed later. Since these narrow gap in-vacuum undulators are most likely to produce coupled bunch instability by the resistive wall impedance and limit the stored beam current, a bunch by bunch feedback system is implemented to suppress coupled bunch instability in the PLS-II. This paper describes the scheme and performance of the PLS-II bunch by bunch feedback system.

Influence of nitrogen-doping concentration on the electronic structure of CuAlO2 by first-principles studies

NASA Astrophysics Data System (ADS)

Liu, Wei-wei; Chen, Hong-xia; Liu, Cheng-lin; Wang, Rong

2017-02-01

Effect of N doping concentration on the electronic structure of N-doped CuAlO2 was investigated by density functional theory based on generalized-gradient approximation plus orbital potential. Lattice parameters a and c both increase with increasing N-doping concentration. Formation energies increase with increasing N doping concentration and all N-doped CuAlO2 were structurally stable. The calculated band gaps for N-doped CuAlO2 narrowed compared to pure CuAlO2, which was attributed to the stronger hybridization between Cu-3d and N-2p states and the downward shift of Cu-3p states in conduction bands. The higher the N-doping concentration is, the narrower the band gap. N-doped CuAlO2 shows a typical p-type semiconductor. The band structure changed from indirect to direct after N doping which will benefit the application of the CuAlO2 materials in optoelectronic and electronic devices.

Superconductivity in the Narrow Gap Semiconductor RbBi 11/3Te 6

DOE PAGES

Malliakas, Christos D.; Chung, Duck Young; Claus, Helmut; ...

2016-10-16

Superconductivity was discovered in the layered compound RbBi 11/3Te 6, featuring Bi vacancies and a narrow band gap of 0.25(2) eV at room temperature. In addition, a sharp superconducting transition at similar to 3.2 K was observed in polycrystalline ingots. The superconducting volume fraction of oriented single crystals is almost 100%, confirming bulk superconductivity. Systematic Se and Sb substitutions in RbBi 11/3-ySb ySe xTe 6-x, revealed a dependence of the superconducting transition on composition that can increase the T c up to similar to 10%. The RbBi 11/3Te 6 system is the first member of the new homologous series Rb[Bimore » 2n+11/3Te 3n+6] with infinite Bi 2Te 3-like layers. Lastly, the large degree of chemical tunability of the electronic structure of the homology via doping and/or substitution gives rise to a new family of superconductors.« less

Nanoantennas for enhancing and confining the magnetic optical field

NASA Astrophysics Data System (ADS)

Grosjean, Thierry; Mivelle, Mathieu; Baida, Fadi I.; Burr, Geoffrey W.; Fischer, Ulrich C.

2011-05-01

We propose different optical antenna structures for enhancing and confining the magnetic optical field. A common feature of these structures are concave corners in thin metal films as locations of the enhanced magnetic field. This proposal is inspired by Babinet's principle as the concave edges are the complementary structures to convex metal corners, which are known to be locations of a strongly enhanced electric field. Bowtie antennas and the bowtie apertures of appropriate size were shown to exhibit resonances in the infrared frequency range with an especially strong enhancement of the electrical field in the gap between 2 convex metal corners. We show by numerical calculations, that the complementary structures, the complementary bowtie aperture - the diabolo antenna - and the complementary bow tie antenna - two closely spaced triangular apertures in a metal film with a narrow gap between two opposing concave corners - exhibit resonances with a strongly enhanced magnetic field at the narrow metal constriction between the concave corners. We suggest sub-wavelength circuits of concave and convex corners as building blocks of planar metamaterials.

Improving Health Care Workers for Seasonal Influenza Vaccination at University Health System: A Paradigm for Closing the Quality Chasm

PubMed Central

Patterson, Jan E.; Cadena, Jose; Prigmore, Teresa; Bowling, Jason; Ayala, Beth Ann; Kirkman, Leni; Parekh, Amruta; Scepanski, Theresa

2011-01-01

Significant gaps in quality and patient safety in the US health-care system have been identified and were reported in the past decade by the Institute of Medicine. Despite recognition of these gaps in “knowing versus doing,” change in health care is slow and difficult. The quality improvement and clinical safety movement is increasing among US medical centers. Our health science center implemented the UT System Clinical Safety and Effectiveness course, providing project-based teaching of quality-improvement tools and principles of patient safety. A quality-improvement project that increased healthcare workers' influenza vaccination rate by 17.8% from that in 2008 to a rate of 76.6% in 2009 serves as a paradigm of how physicians can lead quality-improvement project teams to narrow the quality chasm (1). Local efforts to narrow the chasm are discussed in the present paper, including inter-professional education in quality improvement and clinical safety. PMID:21686222

Twentieth century arroyo changes in Chaco Culture National Historical Park

USGS Publications Warehouse

Gellis, Allen C.

2002-01-01

Chaco Wash arroyo channel changes in the 20th century have become a major concern of the National Park Service. Several archeologic and cultural sites are located in the Chaco Wash corridor; thus, increased erosional activity of Chaco Wash, such as channel incision and increased meandering, may affect these sites. Through field surveys, photogrammetric analyses, and reviews of existing reports and maps, arroyo changes at Chaco Culture National Historic Park were documented. Arroyo changes were documented for the inner active channel and the entire arroyo cross section. The inner channel of Chaco Wash evolved from a wide, braided channel in the 1930's to a narrower channel with a well-developed flood plain by the 1970's. From 1934 to 1973 the active channel narrowed an average of 26 meters, and from the 1970's to 2000 the channel narrowed an average of 9 meters. Overall from 1934 to 2000, the inner channel narrowed an average of 30 meters. From 1934 to 2000, the top of Chaco Wash widened at four cross sections, narrowed at one, and remained the same at another. The top of Chaco Wash widened at a rate of 0.4 meter per year from the 1970's to 2000 compared with 0.2 meter per year from 1934 to 1973. At 50-percent depth or halfway down the arroyo channel, four cross sections widened and two cross sections narrowed from 1934 to 2000. Rates of widening at 50-percent depth decreased from 0.2 meter per year from 1934 to 1973 to 0.1 meter per year from the 1970's to 2000. From 1934 to 2000, arroyo depth decreased at five of six cross sections and increased at one cross section. Arroyo depth between 1934 and 1973 decreased an average 1.4 meters from aggradation and between the 1970's and 2000 increased an average 0.4 meter from channel scour. From 1934 to 2000, arroyo cross-sectional area decreased at all six cross sections. Cross-sectional areas in Chaco Wash decreased from 1934 to 1973 as a result of sediment deposition and both decreased and increased from the 1970's to 2000. The cross-sectional area decreased by the 1970's due to channel narrowing and flood-plain formation. Increases in cross-sectional area are from channel scour and channel widening. Photogrammetric analyses of volumetric changes for a 1.7-kilometer reach of Chaco Wash showed sediment deposition from 1934 to 1973 of 64 square meters per unit length of channel over 1.7 kilometers to erosion from 1973 to 2000 of 7 square meters per unit length of channel. Chaco Wash evolved from a braided channel in the 1930's to a narrow, sinuous inner channel by the 1970's. Chaco Wash was widening in the 1930's, leading to sediment deposition and formation of an inner flood plain. Channel narrowing resulted from increased sediment deposition on the flood plain. Sediment deposition may be related to a decrease in peak flows, an increase in flood-plain vegetation, or an increase in the transport of fine-grained sediment. Increases in bankfull depth of Chaco Wash between the 1970's and 2000 were due to aggradation of the flood plain and channel scour. Thus, rates of aggradation and cross-sectional filling were greater from 1934 to the 1970's than from the 1970's to 2000.

Nature of the abnormal band gap narrowing in highly crystalline Zn1-xCoxO nanorods

NASA Astrophysics Data System (ADS)

Qiu, Xiaoqing; Li, Liping; Li, Guangshe

2006-03-01

Highly crystalline Zn1-xCoxO nanorods were prepared using a hydrothermal method. With increasing Co2+ dopant concentration, the lattice volume enlarged considerably, which is associated with the enhanced repulsive interactions of defect dipole moments on the wall surfaces. This lattice modification produced a significant decrease in band gap energies with its magnitude that followed the relationship, ΔEg=ΔE0•(e-x/B-1), where x and B are Co2+ dopant concentration and a constant, respectively. The abnormal band gap energies were indicated to originate from the sp-d exchange interactions that are proportional to the square of lattice volume.

Mind the Gap: Persistent and Mobile Organic Compounds-Water Contaminants That Slip Through.

PubMed

Reemtsma, Thorsten; Berger, Urs; Arp, Hans Peter H; Gallard, Hervé; Knepper, Thomas P; Neumann, Michael; Quintana, José Benito; Voogt, Pim de

2016-10-04

The discharge of persistent and mobile organic chemicals (PMOCs) into the aquatic environment is a threat to the quality of our water resources. PMOCs are highly polar (mobile in water) and can pass through wastewater treatment plants, subsurface environments and potentially also drinking water treatment processes. While a few such compounds are known, we infer that their number is actually much larger. This Feature highlights the issue of PMOCs from an environmental perspective and assesses the gaps that appear to exist in terms of analysis, monitoring, water treatment and regulation. On this basis we elaborate strategies on how to narrow these gaps with the intention to better protect our water resources.

Imaging a Central Ionized Component, a Narrow Ring, and the CO Snowline in the Multigapped Disk of HD 169142

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

Macías, Enrique; Anglada, Guillem; Osorio, Mayra

2017-04-01

We report Very Large Array observations at 7 mm, 9 mm, and 3 cm toward the pre-transitional disk of the Herbig Ae star HD 169142. These observations have allowed us to study the millimeter emission of this disk with the highest angular resolution so far (0.″12 × 0.″09, or 14 au × 11 au, at 7 mm). Our 7 and 9 mm images show a narrow ring of emission at a radius of ∼25 au tracing the outer edge of the inner gap. This ring presents an asymmetric morphology that could be produced by dynamical interactions between the disk andmore » forming planets. Additionally, the azimuthally averaged radial intensity profiles of the 7 and 9 mm images confirm the presence of the previously reported gap at ∼45 au and reveal a new gap at ∼85 au. We analyzed archival DCO{sup +}(3–2) and C{sup 18}O(2–1) ALMA observations, showing that the CO snowline is located very close to this third outer gap. This suggests that growth and accumulation of large dust grains close to the CO snowline could be the mechanism responsible for this proposed outer gap. Finally, a compact source of emission is detected at 7 mm, 9 mm, and 3 cm toward the center of the disk. Its flux density and spectral index indicate that it is dominated by free–free emission from ionized gas, which could be associated with the photoionization of the inner disk, an independent object, or an ionized jet.« less

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

Tabeshian, Maryam; Wiegert, Paul A., E-mail: mtabeshi@uwo.ca

Structures observed in debris disks may be caused by gravitational interaction with planetary or stellar companions. These perturbed disks are often thought to indicate the presence of planets and offer insights into the properties of both the disk and the perturbing planets. Gaps in debris disks may indicate a planet physically present within the gap, but such gaps can also occur away from the planet’s orbit at mean-motion resonances (MMRs), and this is the focus of our interest here. We extend our study of planet–disk interaction through MMRs, presented in an earlier paper, to systems in which the perturbing planetmore » has moderate orbital eccentricity, a common occurrence in exoplanetary systems. In particular, a new result is that the 3:1 MMR becomes distinct at higher eccentricity, while its effects are absent for circular planetary orbits. We also only consider gravitational interaction with a planetary body of at least 1 M {sub J}. Our earlier work shows that even a 1 Earth mass planet can theoretically open an MMR gap; however, given the narrow gap that can be opened by a low-mass planet, its observability would be questionable. We find that the widths, locations, and shapes of two prominent structures, the 2:1 and 3:1 MMRs, could be used to determine the mass, semimajor axis, and eccentricity of the planetary perturber and present an algorithm for doing so. These MMR structures can be used to narrow the position and even determine the planetary properties (such as mass) of any inferred but as-yet-unseen planets within a debris disk. We also briefly discuss the implications of eccentric disks on brightness asymmetries and their dependence on the wavelengths with which these disks are observed.« less

The role of school performance in narrowing gender gaps in the formation of STEM aspirations: a cross-national study.

PubMed

Mann, Allison; Legewie, Joscha; DiPrete, Thomas A

2015-01-01

This study uses cross-national evidence to estimate the effect of school peer performance on the size of the gender gap in the formation of STEM career aspirations. We argue that STEM aspirations are influenced not only by gender stereotyping in the national culture but also by the performance of peers in the local school environment. Our analyses are based on the Program for International Student Assessment (PISA). They investigate whether 15-year-old students from 55 different countries expect to have STEM jobs at the age of 30. We find considerable gender differences in the plans to pursue careers in STEM occupations in all countries. Using PISA test scores in math and science aggregated at the school level as a measure of school performance, we find that stronger performance environments have a negative impact on student career aspirations in STEM. Although girls are less likely than boys to aspire to STEM occupations, even when they have comparable abilities, boys respond more than girls to competitive school performance environments. As a consequence, the aspirations gender gap narrows for high-performing students in stronger performance environments. We show that those effects are larger in countries that do not sort students into different educational tracks.

The influence of narrow optical gap silver oxide on zinc oxide nanoparticles produced by microwave-assisted colloidal synthesis: photocatalytic studies

NASA Astrophysics Data System (ADS)

Prakoso, S. P.; Paramarta, V.; Tju, H.; Taufik, A.; Saleh, R.

2016-11-01

This paper reports a photocatalytic study on wide band gap zinc oxide (ZnO) incorporated by narrow band gap silver oxide (Ag2O), namely Ag2O/ZnO nanocomposites, which were prepared by colloidal synthesis with microwave supports. The Ag2O/ZnO nanocomposites were prepared with three different molar ratios (MR) of Ag2O to ZnO (MR: 0.25, 0.5 and 0.75). In order to confirm qualitatively the concentration ratio of Ag2O in ZnO, crystal phase intensity ratio was executed by peak indexing from x-ray diffraction. The Ag2O/ZnO nanocomposites properties were further investigated using diffuse reflectance spectroscopy. The nanocomposites were tested for the degradation of organic dyes solutions under visible and UV light irradiations. The photocatalytic activity of Ag2O/ZnO nanocomposites under visible light increased with increasing molar ratio of Ag2O to ZnO, while the opposite trends observed under UV light irradiation. The improvement of photoabsorption together with photocatalytic activities might be suspected due to the p-n heterojunction structure in Ag2O/ZnO nanocomposites. The corresponding mechanism will be discussed in detail.

The Equal Pay Act: The First 30 Years.

ERIC Educational Resources Information Center

Crampton, Suzanne M.; Hodge, John W.; Mishra, Jitendra M.

1997-01-01

Analysis by decade of the effects of the Equal Pay Act of 1963 shows that women's earnings relative to men's increased by 10 cents from 1960-1990. Black and Hispanic women's earnings lagged further behind. More education and experience did not help women narrow the gap. (SK)

Discriminatory Discipline: Trends and Issues

ERIC Educational Resources Information Center

Whitford, Denise K.; Katsiyannis, Antonis; Counts, Jennifer

2016-01-01

Discriminatory discipline has been widely documented for decades, yet little progress has been made to narrow the gap. Due to the long-standing history of discriminatory discipline, current nationwide data, and recent federal initiatives, there is a need for a comprehensive examination of this critical issue. Therefore, we discuss populations…

Evaluation of shared lane markings in Miami Beach, Florida [summary].

DOT National Transportation Integrated Search

2012-01-01

On urban streets, bicyclists must often ride in the narrow gap between traffic and parked cars, where they may become victims of a "dooring" crash, in which the door of a parked car opens suddenly into the bicyclist's path. The bicyclist can be injur...

Gender in clinical neuropsychology: practice survey trends and comparisons outside the specialty.

PubMed

Sweet, Jerry J; Lee, Catherine; Guidotti Breting, Leslie M; Benson, Laura M

2018-02-01

This paper describes gender-related trends within clinical neuropsychology, based primarily on recurrent practice surveys within the specialty and, to a lesser extent, job-related information from medical specialties and the general U.S. labor market. Chronological and cross-sectional analyses of professional practice survey data from 2005, 2010, and 2015 relevant to gender. As is common with survey data, descriptive analysis and independent samples t-tests were conducted. Longitudinal data allowed for examination of gender trends, as well as observations of change and stability of factors associated with gender, over time. Women have become dominant in number in clinical neuropsychology, and also comprise a vast majority of practitioners entering the specialty. Gender differences are noted in professional identity, work status, work settings, types of career satisfaction, and retirement expectations. Women are more likely to identify work environment and personal/family obstacles to aspects of career satisfaction. A gender pay gap was found at all time points and is not narrowing. As is true nationally, multiple factors appear related to the gender pay gap in clinical neuropsychology. Women in neuropsychology are now dominant in number, and their presence is strongly associated with specific practice patterns, such as greater institutional employment, less involvement in forensic practice, and strong involvement in pediatric practice, which may be maintaining the sizeable gender pay gap in neuropsychology. As the proportion of women neuropsychologists continues to increase, flexible work hours, and alternative means of remuneration may be needed to offset current disproportionate family-related responsibilities.

Time Trends and Policy Gaps: The Case of Alcohol Misuse Among Adolescents in Lebanon.

PubMed

Ghandour, Lilian; Afifi, Rima; Fares, Sonia; El Salibi, Noura; Rady, Alissar

2015-01-01

Monitoring studies are crucial for informing and reforming local policies. Using the Lebanon 2005 and 2011 Global School-based Student Health Surveys (GSHS), alcohol time trends were described, policy gaps were identified, and harm reduction policy recommendations were made. In 2005 and 2011, 100 (n = 5109 students) and 44 (n = 2784 students) middle schools were surveyed, respectively. Self-reported cross-sectional data on alcohol use among 7-9th graders in private and public schools was collected including 30-day prevalence, lifetime drunkenness, alcohol-related problems, and sources of alcohol. In 2011, the majority (87%) had alcohol before turning 14. Between 2005 and 2011, past 30-day alcohol use had increased by 40% and lifetime drunkenness by 50% in the total sample (122% among females with a narrowing in the gender gap). Drinking was regular for more than a third of the past 30-day drinkers (drank two or more drinks on the days they drank). Male adolescents were more likely to obtain alcohol from "stores" or "through their friends" whereas females' main source was their "family." One in twenty reported experiencing alcohol-related problems (e.g., getting into fights with family/friends and skipping school). Conclusion/Importance: Evidence-informed policy implications include enforcing a minimum legal drinking age, regulating alcohol advertising, and marketing particularly those targeting youth and women, and ensuring the availability of youth-friendly services. Public messages to increase awareness among all stakeholders including youth, their parents, and larger community are also needed.

Generating evidence to narrow the treatment gap for mental disorders in sub-Saharan Africa: rationale, overview and methods of AFFIRM.

PubMed

Lund, C; Alem, A; Schneider, M; Hanlon, C; Ahrens, J; Bandawe, C; Bass, J; Bhana, A; Burns, J; Chibanda, D; Cowan, F; Davies, T; Dewey, M; Fekadu, A; Freeman, M; Honikman, S; Joska, J; Kagee, A; Mayston, R; Medhin, G; Musisi, S; Myer, L; Ntulo, T; Nyatsanza, M; Ofori-Atta, A; Petersen, I; Phakathi, S; Prince, M; Shibre, T; Stein, D J; Swartz, L; Thornicroft, G; Tomlinson, M; Wissow, L; Susser, E

2015-06-01

There is limited evidence on the acceptability, feasibility and cost-effectiveness of task-sharing interventions to narrow the treatment gap for mental disorders in sub-Saharan Africa. The purpose of this article is to describe the rationale, aims and methods of the Africa Focus on Intervention Research for Mental health (AFFIRM) collaborative research hub. AFFIRM is investigating strategies for narrowing the treatment gap for mental disorders in sub-Saharan Africa in four areas. First, it is assessing the feasibility, acceptability and cost-effectiveness of task-sharing interventions by conducting randomised controlled trials in Ethiopia and South Africa. The AFFIRM Task-sharing for the Care of Severe mental disorders (TaSCS) trial in Ethiopia aims to determine the acceptability, affordability, effectiveness and sustainability of mental health care for people with severe mental disorder delivered by trained and supervised non-specialist, primary health care workers compared with an existing psychiatric nurse-led service. The AFFIRM trial in South Africa aims to determine the cost-effectiveness of a task-sharing counselling intervention for maternal depression, delivered by non-specialist community health workers, and to examine factors influencing the implementation of the intervention and future scale up. Second, AFFIRM is building individual and institutional capacity for intervention research in sub-Saharan Africa by providing fellowship and mentorship programmes for candidates in Ethiopia, Ghana, Malawi, Uganda and Zimbabwe. Each year five Fellowships are awarded (one to each country) to attend the MPhil in Public Mental Health, a joint postgraduate programme at the University of Cape Town and Stellenbosch University. AFFIRM also offers short courses in intervention research, and supports PhD students attached to the trials in Ethiopia and South Africa. Third, AFFIRM is collaborating with other regional National Institute of Mental Health funded hubs in Latin America, sub-Saharan Africa and south Asia, by designing and executing shared research projects related to task-sharing and narrowing the treatment gap. Finally, it is establishing a network of collaboration between researchers, non-governmental organisations and government agencies that facilitates the translation of research knowledge into policy and practice. This article describes the developmental process of this multi-site approach, and provides a narrative of challenges and opportunities that have arisen during the early phases. Crucial to the long-term sustainability of this work is the nurturing and sustaining of partnerships between African mental health researchers, policy makers, practitioners and international collaborators.

Neutron optics concept for the materials engineering diffractometer at the ESS

NASA Astrophysics Data System (ADS)

Šaroun, J.; Fenske, J.; Rouijaa, M.; Beran, P.; Navrátil, J.; Lukáš, P.; Schreyer, A.; Strobl, M.

2016-09-01

The Beamline for European Materials Engineering Research (BEER) has been recently proposed to be built at the European Spallation Source (ESS). The presented concept of neutron delivery optics for this instrument addresses the problems of bi-spectral beam extraction from a small moderator, optimization of neutron guides profile for long-range neutron transport and focusing at the sample under various constraints. They include free space before and after the guides, a narrow guide section with gaps for choppers, closing of direct line of sight and cost reduction by optimization of the guides cross-section and coating. A system of slits and exchangeable focusing optics is proposed in order to match various wavelength resolution options provided by the pulse shaping and modulation choppers, which permits to efficiently trade resolution for intensity in a wide range. Simulated performance characteristics such as brilliance transfer ratio are complemented by the analysis of the histories of “useful” neutrons obtained by back tracing neutrons hitting the sample, which helps to optimize some of the neutron guide parameters such as supermirror coating.

Fuel inventory and deposition in castellated structures in JET-ILW

NASA Astrophysics Data System (ADS)

Rubel, M.; Petersson, P.; Zhou, Y.; Coad, J. P.; Lungu, C.; Jepu, I.; Porosnicu, C.; Matveev, D.; Kirschner, A.; Brezinsek, S.; Widdowson, A.; Alves, E.; Contributors, JET

2017-06-01

Since 2011 the JET tokamak has been operated with a metal ITER-like wall (JET-ILW) including castellated beryllium limiters and lamellae-type bulk tungsten tiles in the divertor. This has allowed for a large scale test of castellated plasma-facing components (PFC). Procedures for sectioning the limiters into single blocks of castellation have been developed. This facilitated morphology studies of morphology of surfaces inside the grooves for limiters after experimental campaigns 2011-2012 and 2013-2014. The deposition in the 0.4-0.5 mm wide grooves of the castellation is ‘shallow’. It reaches 1-2 mm into the 12 mm deep gap. Deuterium concentrations are small (mostly below 1  ×  1018 cm-2). The estimated total amount of deuterium in all the castellated limiters does not exceed the inventory of the plasma-facing surfaces (PFS) of the limiters. There are only traces of Ni, Cr and Fe deposited in the castellation gaps. The same applies to the carbon content. Also low deposition of D, Be and C has been measured on the sides of the bulk tungsten lamellae pieces. Modelling clearly reflects: (a) a sharp decrease in the measured deposition profiles and(b) an increase in deposition with the gap width. Both experimental and modelling data give a strong indication and information to ITER that narrow gaps in the castellated PFC are essential. X-ray diffraction on PFS has clearly shown two distinct composition patterns: Be with an admixture of Be-W intermetallic compounds (e.g. Be22W) in the deposition zone, whilst only pure Be has been detected in the erosion zone. The lack of compound formation in the erosion zone indicates that no distinct changes in the thermo-mechanical properties of the Be PFC might be expected.

The widening gender gap in marijuana use prevalence in the U.S. during a period of economic change, 2002–2014

PubMed Central

Carliner, Hannah; Mauro, Pia M.; Brown, Qiana L.; Shmulewitz, Dvora; Rahim-Juwel, Reanne; Sarvet, Aaron L.; Wall, Melanie M.; Martins, Silvia S.; Carliner, Geoffrey; Hasin, Deborah S.

2017-01-01

Aim Concurrently with increasingly permissive attitudes towards marijuana use and its legalization, the prevalence of marijuana use has increased in recent years in the U.S. Substance use is generally more prevalent in men than women, although for alcohol, the gender gap is narrowing. However, information is lacking on whether time trends in marijuana use differ by gender, or whether socioeconomic status in the context of the Great Recession may affect these changes. Methods Using repeated cross-sectional data from the National Survey on Drug Use and Health (2002–2014), we examined changes over time in prevalence of past-year marijuana use by gender, and whether gender differences varied across income levels. After empirically determining a change point in use in 2007, we used logistic regression to test interaction terms including time, gender, and income level. Results Prevalence of marijuana use increased for both men (+4.0%) and women (+2.7%) from 2002 to 2014, with all of the increase occurring from 2007 to 2014. Increases were greater for men, leading to a widening of the gender gap over time (p < 0.001). This divergence occurred primarily due to increased prevalence among men in the lowest income level (+6.2%) from 2007 to 2014. Conclusion Our findings are consistent with other studies documenting increased substance use during times of economic insecurity, especially among men. Corresponding with the Great Recession and lower employment rate beginning in 2007, low-income men showed the greatest increases in marijuana use during this period, leading to a widening of the gender gap in prevalence of marijuana use over time. PMID:27875801

The widening gender gap in marijuana use prevalence in the U.S. during a period of economic change, 2002-2014.

PubMed

Carliner, Hannah; Mauro, Pia M; Brown, Qiana L; Shmulewitz, Dvora; Rahim-Juwel, Reanne; Sarvet, Aaron L; Wall, Melanie M; Martins, Silvia S; Carliner, Geoffrey; Hasin, Deborah S

2017-01-01

Concurrently with increasingly permissive attitudes towards marijuana use and its legalization, the prevalence of marijuana use has increased in recent years in the U.S. Substance use is generally more prevalent in men than women, although for alcohol, the gender gap is narrowing. However, information is lacking on whether time trends in marijuana use differ by gender, or whether socioeconomic status in the context of the Great Recession may affect these changes. Using repeated cross-sectional data from the National Survey on Drug Use and Health (2002-2014), we examined changes over time in prevalence of past-year marijuana use by gender, and whether gender differences varied across income levels. After empirically determining a change point in use in 2007, we used logistic regression to test interaction terms including time, gender, and income level. Prevalence of marijuana use increased for both men (+4.0%) and women (+2.7%) from 2002 to 2014, with all of the increase occurring from 2007 to 2014. Increases were greater for men, leading to a widening of the gender gap over time (p<0.001). This divergence occurred primarily due to increased prevalence among men in the lowest income level (+6.2%) from 2007 to 2014. Our findings are consistent with other studies documenting increased substance use during times of economic insecurity, especially among men. Corresponding with the Great Recession and lower employment rate beginning in 2007, low-income men showed the greatest increases in marijuana use during this period, leading to a widening of the gender gap in prevalence of marijuana use over time. Copyright © 2016. Published by Elsevier Ireland Ltd.

Impact of the Nanoscale Gap Morphology on the Plasmon Coupling in Asymmetric Nanoparticle Dimer Antennas.

PubMed

Popp, Paul S; Herrmann, Janning F; Fritz, Eva-Corinna; Ravoo, Bart Jan; Höppener, Christiane

2016-03-23

Coupling of plasmon resonances in metallic gap antennas is of interest for a wide range of applications due to the highly localized strong electric fields supported by these structures, and their high sensitivity to alterations of their structure, geometry, and environment. Morphological alterations of asymmetric nanoparticle dimer antennas with (sub)-nanometer size gaps are assigned to changes of their optical response in correlative dark-field spectroscopy and high-resolution transmission electron microscopy (HR-TEM) investigations. This multimodal approach to investigate individual dimer structures clearly demonstrates that the coupling of the plasmon modes, in addition to well-known parameters such as the particle geometry and the gap size, is also affected by the relative alignment of both nanoparticles. The investigations corroborate that the alignment of the gap forming facets, and with that the gap area, is crucial for their scattering properties. The impact of a flat versus a rounded gap structure on the optical properties of equivalent dimers becomes stronger with decreasing gap size. These results hint at a higher confinement of the electric field in the gap and possibly a different onset of quantum transport effects for flat and rounded gap antennas in corresponding structures for very narrow gaps. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiple components in narrow planetary rings.

PubMed

Benet, L; Merlo, O

2008-01-11

The phase-space volume of regions of regular or trapped motion, for bounded or scattering systems with 2 degrees of freedom, respectively, displays universal properties. In particular, drastic reductions in the volume (gaps) are observed at specific values of a control parameter. Using the stability resonances we show that they, and not the mean-motion resonances, account for the position of these gaps. For more degrees of freedom, exciting these resonances divides the regions of trapped motion. For planetary rings, we demonstrate that this mechanism yields rings with multiple components.

Field-Induced-Gap Infrared Detectors

NASA Technical Reports Server (NTRS)

Elliott, C. Thomas

1990-01-01

Semimetals become semiconductors under applied magnetic fields. New detectors require less cooling equipment because they operate at temperatures higher than liquid-helium temperatures required by extrinsic-semiconductor detectors. Magnetic fields for detectors provided by electromagnets based on recently-discovered high-transition-temperature superconducting materials. Detector material has to be semiconductor, in which photon absorbed by exciting electron/hole pair across gap Eg of forbidden energies between valence and conduction energy bands. Magnetic- and compositional-tuning effects combined to obtain two-absorber detector having narrow passband. By variation of applied magnetic field, passband swept through spectrum of interest.

The fluid mechanics of continuous flow electrophoresis in perspective

NASA Technical Reports Server (NTRS)

Saville, D. A.

1980-01-01

Buoyancy alters the flow in continuous flow electrophoresis chambers through the mechanism of hydrodynamic instability and, when the instability is supressed by careful cooling of the chamber boundaries, by restructuring the axial flow. The expanded roles of buoyancy follow upon adapting the size of the chamber and the electric field so as to fractionate certain sorts of cell populations. Scale-up problems, hydrodynamic stability and the altered flow fields are discussed to show how phenomena overlooked in the design and operations of narrow-gap devices take on an overwhelming importance in wide-gap chambers

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.

The direct exchange mechanism of induced spin polarization of low-dimensional π-conjugated carbon- and h-BN fragments at LSMO(001) MnO-terminated interfaces

NASA Astrophysics Data System (ADS)

Kuklin, Artem V.; Kuzubov, Alexander A.; Kovaleva, Evgenia A.; Lee, Hyosun; Sorokin, Pavel B.; Sakai, Seiji; Entani, Shiro; Naramoto, Hiroshi; Avramov, Paul

2017-10-01

Induced spin polarization of π-conjugated carbon and h-BN low dimensional fragments at the interfaces formed by deposition of pentacene molecule and narrow zigzag graphene and h-BN nanoribbons on MnO2-terminated LSMO(001) thin film was studied using GGA PBE+U PAW D3-corrected approach. Induced spin polarization of π-conjugated low-dimensional fragments is caused by direct exchange with Mn ions of LSMO(001) MnO-derived surface. Due to direct exchange, the pentacene molecule changes its diamagnetic narrow-band gap semiconducting nature to the ferromagnetic semiconducting state with 0.15 eV energy shift between spin-up and spin-down valence bands and total magnetic moment of 0.11 μB. Direct exchange converts graphene nanoribbon to 100% spin-polarized half-metal with large amplitude of spin-up electronic density at the Fermi level. The direct exchange narrows the h-BN nanoribbon band gap from 4.04 to 1.72 eV in spin-up channel and converts the h-BN ribbon semiconducting diamagnetic nature to a semiconducting magnetic one. The electronic structure calculations demonstrate a possibility to control the spin properties of low-dimensional π-conjugated carbon and h-BN fragments by direct exchange with MnO-derived LSMO(001) surface for spin-related applications.

A detailed analysis of the energy levels configuration existing in the band gap of supersaturated silicon with titanium for photovoltaic applications

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

Pérez, E.; Dueñas, S.; Castán, H.

2015-12-28

The energy levels created in supersaturated n-type silicon substrates with titanium implantation in the attempt to create an intermediate band in their band-gap are studied in detail. Two titanium ion implantation doses (10{sup 13 }cm{sup -2} and 10{sup 14 }cm{sup -2}) are studied in this work by conductance transient technique and admittance spectroscopy. Conductance transients have been measured at temperatures of around 100 K. The particular shape of these transients is due to the formation of energy barriers in the conduction band, as a consequence of the band-gap narrowing induced by the high titanium concentration. Moreover, stationary admittance spectroscopy results suggest the existencemore » of different energy level configuration, depending on the local titanium concentration. A continuum energy level band is formed when titanium concentration is over the Mott limit. On the other hand, when titanium concentration is lower than the Mott limit, but much higher than the donor impurity density, a quasi-continuum energy level distribution appears. Finally, a single deep center appears for low titanium concentration. At the n-type substrate, the experimental results obtained by means of thermal admittance spectroscopy at high reverse bias reveal the presence of single levels located at around E{sub c}-425 and E{sub c}-275 meV for implantation doses of 10{sup 13 }cm{sup −2} and 10{sup 14 }cm{sup −2}, respectively. At low reverse bias voltage, quasi-continuously distributed energy levels between the minimum of the conduction bands, E{sub c} and E{sub c}-450 meV, are obtained for both doses. Conductance transients detected at low temperatures reveal that the high impurity concentration induces a band gap narrowing which leads to the formation of a barrier in the conduction band. Besides, the relationship between the activation energy and the capture cross section values of all the energy levels fits very well to the Meyer-Neldel rule. As it is known, the Meyer-Neldel rule typically appears in processes involving multiple excitations, like carrier capture and emission in deep levels, and it is generally observed in disordered systems. The obtained Meyer-Neldel energy value, 15.19 meV, is very close to the value obtained in multicrystalline silicon samples contaminated with iron (13.65 meV), meaning that this energy value could be associated to the phonons energy in this kind of substrates.« less

Google Scholar and the Continuing Education Literature

ERIC Educational Resources Information Center

Howland, Jared L.; Howell, Scott; Wright, Thomas C.; Dickson, Cody

2009-01-01

The recent introduction of Google Scholar has renewed hope that someday a powerful research tool will bring continuing education literature more quickly, freely, and completely to one's computer. The authors suggest that using Google Scholar with other traditional search methods will narrow the research gap between what is discoverable and…

Greater Expectations

ERIC Educational Resources Information Center

McCloskey, Patrick J.

2006-01-01

Julius Bennett was once a disinterested student destined to become a dropout. Then he enrolled in Amistad Academy, an academically focused charter middle school intent on narrowing the achievement gap between urban and suburban kids located in New Haven, Connecticut. Now Julius is making plans for college. In this article the author details the…

The Traditional Approach to Developmental Education: Background and Effectiveness. Research Brief

ERIC Educational Resources Information Center

Horn, Aaron S.; Asmussen, John G.

2014-01-01

A significant challenge in higher education is to narrow the educational attainment gap between academically prepared and unprepared students. To this end, developmental or remedial education is intended to improve the academic skills and knowledge of students who are unprepared for undergraduate coursework, particularly in the areas of…

Black Women's Career Aspirations

ERIC Educational Resources Information Center

Farley, Jennie; And Others

1977-01-01

A two-page questionnaire dealing with career aspirations and expectations was administered to undergraduates at four institutions. Results suggest Black women as a group predict they will earn less than Black males; white women as a group predict they will earn less than white men but the pay gap is narrower. (Author)

Labor Force Experience of Women from "Generation X."

ERIC Educational Resources Information Center

DiNatale, Marisa; Boraas, Stephanie

2002-01-01

In 2000, women aged 25-34 years participated in the labor force in greater proportions, were more educated, earned more, and enjoyed more labor market benefits than their counterparts 25 years earlier. The earnings gap between young women and men narrowed substantially during the period. (Contains 18 references.) (Author)

A review of concentrated flow erosion processes on rangelands: fundamental understanding and knowledge gaps

USDA-ARS?s Scientific Manuscript database

Concentrated flow erosion processes are distinguished from splash and sheetflow processes in their enhanced ability to mobilize and transport large amounts of soil, water and dissolved elements. On rangelands, soil, nutrients and water are scarce and only narrow margins of resource losses are tolera...

Characteristics of Female College Student Drug Use.

ERIC Educational Resources Information Center

Traub, Stuart H.

1983-01-01

Examined female college students' (N=466) drug use, marihuana use in particular. Results indicated that the gap in marihuana usage patterns between females and males has substantially narrowed. Female marihuana users used other drugs quite extensively and had friends who use marihuana. Peer influence was a major factor in drug use. (JAC)

Culturally Responsive Differentiated Instruction: Narrowing Gaps between Best Pedagogical Practices Benefiting All Learners

ERIC Educational Resources Information Center

Santamaria, Lorri J.

2009-01-01

Background/Context: Because of its special education association, differentiated instruction (DI) is a topic of concern for many educators working with culturally and linguistically diverse (CLD) learners, whereby bilingual, multicultural, and culturally responsive teaching (CRT) is considered more appropriate for responding to cultural and…

Algebra Homework: A Sandwich!

ERIC Educational Resources Information Center

Jackson, D. Bruce

2014-01-01

At a time when the debate continues over whether homework is overused, optional, or essential or favors well-off students over those with little home support, teachers must understand ways in which effective homework strategies can help narrow the achievement gap. Vatterott (2009, p. 94) argues convincingly that the "old paradigm" of…

Chronic Absenteeism and Preschool Children's Executive Functioning Skills Development

ERIC Educational Resources Information Center

Fuhs, Mary Wagner; Nesbitt, Kimberly Turner; Jackson, Hannah

2018-01-01

Investments in preschool programs for children from disadvantaged backgrounds have historically been supported by research showing that these programs help children build school readiness skills and narrow the income-achievement gap. However, results from recent studies of the links between preschool participation and increases in school readiness…

The Decisions We Make about Data

ERIC Educational Resources Information Center

Parsley, James F.

2004-01-01

In this article, the author suggests that leaders need to pause and ask, Is the school environment becoming one of fear and frustration with diminishing regard for personal passion, interest or creativity in teachers and students? Is it possible to narrow the achievement gap on high-stakes assessments while also fostering creativity, limitless…

Technology in Learning: Narrowing the Gender Gap?

ERIC Educational Resources Information Center

Kaino, Luckson Muganyizi

2008-01-01

The introduction of Information and Communication Technology (ICT) into the school curricula raised some hopes that it could minimize gender differences in learning. The interactive nature of ICT materials was believed to provide a favorable environment especially for girls to learn. This article reports the findings of the study that analyzed…

78 FR 22451 - Proposed Priorities, Requirements, Definitions, and Selection Criteria-Race to the Top-District...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-16

..., system-changing reforms designed to improve student achievement, narrow achievement gaps, and increase... personalize education for all students in their schools. The U.S. Department of Education (Department... teaching that would directly improve student achievement and educator effectiveness. Summary of the Major...

Conceptualizing Essential Components of Effective High Schools

ERIC Educational Resources Information Center

Preston, Courtney; Goldring, Ellen; Guthrie, J. Edward; Ramsey, Russell; Huff, Jason

2017-01-01

Three decades of reform aimed at improving disadvantaged student achievement have not substantially narrowed achievement and graduation gaps. This article reviews the research around eight essential components of effective high schools emerging from a review of the effective schools and high school reform literature, and provides a framework for…

Missing Pieces of the Educational Reform Agenda: Or, Why the First and Second Waves.

ERIC Educational Resources Information Center

Hawley, Willis D.

1988-01-01

Contends that two of the most important goals of educational reform should be (1) narrowing the learning gap between high- and low-achieving pupils; and (2) developing in all children a greater capacity for higher-order thinking and problem-solving skills. (TE)

Shock-induced flow separation and the orbiter thermal protection system

NASA Astrophysics Data System (ADS)

Waiter, S.-A.

The Space Shuttle orbiter's thermal protection system (TPS) is composed of reusable tiles separated by narrow gaps that accommodate the contraction and expansion of the aluminum structure that the tiles protect. When local pressure gradients exist, air flows through the tile gaps and releases heat energy by convection. The gaps represent a heat short to the structure, strain isolator pad (SIP), and filler bar. A typical problem is the pressure gradient created during entry by body flap deflection. After a brief description of how this problem affects the Space Shuttle orbiter, a theoretical and experimental review of the major parameters involved in gap heating are analyzed. Then, a review of well-known classical methods to resolve the gap aeroheating problem in the presence of a pressure gradient is presented, and a few solutions are illustrated to assess the sensitivity of each one. The following section starts with a basic relationship (called "eyeball" because of its simplicity) and follows the results up through the most modern engineering approach available in the literature. It shows that in all cases calculated significant areas of overtemperature were predicted. However, none of these methods could be correlated by experimental data. Lastly, the paper presents the solution obtained by using the most sophisticated method, based upon the Navier-Stokes equations. This approach shows excellent correlation with wind tunnel data. The application to four trajectory time points shows less severe results than the other methods. This can be explained by the introduction of a certain amount of conservatism to account for uncertainties inherent in the previous analyses. No correlation of this "exact solution" with the simple preestablished relationships has been found, indicating that more parameters than expected could be involved. However, an after-the-fact, semi-empirical engineering solution that fits the Navier-Stokes solution with good agreement was established.

Interplay of Cu and oxygen vacancy in optical transitions and screening of excitons in ZnO:Cu films

NASA Astrophysics Data System (ADS)

Darma, Yudi; Seng Herng, Tun; Marlina, Resti; Fauziah, Resti; Ding, Jun; Rusydi, Andrivo

2014-02-01

We study room temperature optics and electronic structures of ZnO:Cu films as a function of Cu concentration using a combination of spectroscopic ellipsometry, photoluminescence, and ultraviolet-visible absorption spectroscopy. Mid-gap optical states, interband transitions, and excitons are observed and distinguishable. We argue that the mid-gap states are originated from interactions of Cu and oxygen vacancy (Vo). They are located below conduction band (Zn4s) and above valence band (O2p) promoting strong green emission and narrowing optical band gap. Excitonic states are screened and its intensities decrease upon Cu doping. Our results show the importance of Cu and Vo driving the electronic structures and optical transitions in ZnO:Cu films.

Electronic and Optical properties of Graphene Nanoribbons

NASA Astrophysics Data System (ADS)

Molinari, Elisa; Ferretti, Andrea; Cardoso, Claudia; Prezzi, Deborah; Ruini, Alice

Narrow graphene nanoribbons (GNRs) exhibit substantial electronic band gaps, and optical properties expected to be fundamentally different from the ones of their parent material graphene. Unlike graphene the optical response of GNRs may be tuned by the ribbon width and the directly related electronic band gap. We have addressed the optical properties of chevron-like and finite-size armchair nanoribbons by computing the fundamental and optical gap from ab initio methods. Our results are in very good agreement with the experimental values obtained by STS, ARPES, and differential reflectance spectroscopy, indicating that this computational scheme can be quantitatively predictive for electronic and optical spectroscopies of nanostructures. These study has been partly supported by the EU Centre of Excellence ''MaX - MAterials design at the eXascale''.

Electronic structure modifications and band gap narrowing in Zn0.95V0.05O

NASA Astrophysics Data System (ADS)

Ahad, Abdul; Majid, S. S.; Rahman, F.; Shukla, D. K.; Phase, D. M.

2018-04-01

We present here, structural, optical and electronic structure studies on Zn0.95V0.05O, synthesized using solid state method. Rietveld refinement of x-ray diffraction pattern indicates no considerable change in the lattice of doped ZnO. The band gap of doped sample, as calculated by Kubelka-Munk transformed reflectance spectra, has been found reduced compared to pure ZnO. Considerable changes in absorbance in UV-Vis range is observed in doped sample. V doping induced decrease in band gap is supported by x-ray absorption spectroscopy measurements. It is experimentally confirmed that conduction band edge in Zn0.95V0.05O has shifted towards Fermi level than in pure ZnO.

Additional flow field studies of the GA(W)-1 airfoil with 30-percent chord Fowler flap including slot-gap variations and cove shape modifications

NASA Technical Reports Server (NTRS)

Wentz, W. H., Jr.; Ostowari, C.

1983-01-01

Experimental measurements were made to determine the effects of slot gap opening and flap cove shape on flap and airfoil flow fields. Test model was the GA(W)-1 airfoil with 0.30c Fowler flap deflected 35 degrees. Tests were conducted with optimum, wide and narrow gaps, and with three cove shapes. Three test angles were selected, corresponding to pre-stall and post-stall conditions. Reynolds number was 2,200,000 and Mach number was 0.13. Force, surface pressure, total pressure, and split-film turbulence measurements were made. Results were compared with theory for those parameters for which theoretical values were available.

17 CFR 240.3a55-4 - Exclusion from definition of narrow-based security index for indexes composed of debt securities.

Code of Federal Regulations, 2010 CFR

2010-04-01

... narrow-based security index for indexes composed of debt securities. 240.3a55-4 Section 240.3a55-4... Miscellaneous Exemptions § 240.3a55-4 Exclusion from definition of narrow-based security index for indexes composed of debt securities. (a) An index is not a narrow-based security index if: (1)(i) Each of the...

Diagnosing climate change impacts and identifying adaptation strategies by involving key stakeholder organisations and farmers in Sikkim, India: Challenges and opportunities.

PubMed

Azhoni, Adani; Goyal, Manish Kumar

2018-06-01

Narrowing the gap between research, policy making and implementing adaptation remains a challenge in many parts of the world where climate change is likely to severely impact water security. This research aims to narrow this gap by matching the adaptation strategies being framed by policy makers to that of the perspectives of development agencies, researchers and farmers in the Himalayan state of Sikkim in India. Our case study examined the perspectives of various stakeholders for climate change impacts, current adaptation strategies, knowledge gaps and adaptation barriers, particularly in the context of implementing the Sikkim State Action Plan on Climate Change through semi-structured interviews carried out with decision makers in the Sikkim State Government, researchers, consultants, local academia, development agencies and farmers. Using Stakeholders Network Analysis tools, this research unravels the complexities of perceiving climate change impacts, identifying strategies, and implementing adaptation. While farmers are less aware about the global phenomenon of climate change impacts for water security, their knowledge of the local conditions and their close interaction with the State Government Agriculture Department provides them opportunities. Although important steps are being initiated through the Sikkim State Action Plan on Climate Change it is yet to deliver effective means of adaptation implementation and hence, strengthening the networks of close coordination between the various implementing agencies will pay dividends. Knowledge gaps and the need for capacity building identified in this research, based on the understandings of key stakeholders are highly relevant to both the research community and for informing policy. Copyright © 2018 Elsevier B.V. All rights reserved.

Flexion and extension gaps created by the navigation-assisted gap technique show small acceptable mismatches and close mutual correlations.

PubMed

Lee, Dae-Hee; Shin, Young-Soo; Jeon, Jin-Ho; Suh, Dong-Won; Han, Seung-Beom

2014-08-01

The aim of this study was to investigate the mechanism underlying the development of gap differences in total knee arthroplasty using the navigation-assisted gap technique and to assess whether these gap differences have statistical significance. Ninety-two patients (105 knees) implanted with cruciate-retaining prostheses using the navigation-assisted gap balancing technique were prospectively analysed. Medial extension and flexion gaps and lateral extension and flexion gaps were measured at full extension and at 90° of flexion. Repeated measures analysis of variance was used to compare the mean values of these four gaps. The correlation coefficient between each pair of gaps was assessed using Pearson's correlation analysis. Mean intra-operative medial and lateral extension gaps were 20.6 ± 2.1 and 21.7 ± 2.2 mm, respectively, and mean intra-operative medial and lateral flexion gaps were 21.6 ± 2.7 and 22.1 ± 2.5 mm, respectively. The pairs of gaps differed significantly (P < 0.05 each), except for the difference between the medial flexion and lateral extension gaps (n.s.). All four gaps were significantly correlated with each other, with the highest correlation between the medial and lateral flexion gaps (r = 0.890, P < 0.001) and the lowest between the medial flexion and lateral extension gaps (r = 0.701, P < 0.001). Medial and lateral flexion and extension gaps created using the navigation-assisted gap technique differed significantly, although the differences between them were <2 mm, and the gaps were closely correlated. These narrow ranges of statistically acceptable gap differences and the strong correlations between gaps should be considered by surgeons, as should the risks of soft tissue over-release or unintentional increases in extension or flexion gap after preparation of the other gap.

Fullerene-Free Organic Solar Cells with an Efficiency of 10.2% and an Energy Loss of 0.59 eV Based on a Thieno[3,4-c]Pyrrole-4,6-dione-Containing Wide Band Gap Polymer Donor.

PubMed

Hadmojo, Wisnu Tantyo; Wibowo, Febrian Tri Adhi; Ryu, Du Yeol; Jung, In Hwan; Jang, Sung-Yeon

2017-09-27

Although the combination of wide band gap polymer donors and narrow band gap small-molecule acceptors achieved state-of-the-art performance as bulk heterojunction (BHJ) active layers for organic solar cells, there have been only several of the wide band gap polymers that actually realized high-efficiency devices over >10%. Herein, we developed high-efficiency, low-energy-loss fullerene-free organic solar cells using a weakly crystalline wide band gap polymer donor, PBDTTPD-HT, and a nonfullerene small-molecule acceptor, ITIC. The excessive intermolecular stacking of ITIC is efficiently suppressed by the miscibility with PBDTTPD-HT, which led to a well-balanced nanomorphology in the PBDTTPD-HT/ITIC BHJ active films. The favorable optical, electronic, and energetic properties of PBDTTPD-HT with respect to ITIC achieved panchromatic photon-to-current conversion with a remarkably low energy loss (0.59 eV).

Mechanism of VHF H2 plasma production at high pressures

NASA Astrophysics Data System (ADS)

Chen, Kuan-Chen; Chiu, Kuo-Feng; Chen, Chia-Fu; Lien, Cheng-Yang; Tsai, Yu-Jer; Lien, Ting-Kuei; Ogiwara, Kohei; Uchino, Kiichiro; Kawai, Yoshinobu

2016-06-01

A VHF H2 plasma was produced by a narrow-gap discharge at high pressures, and the plasma parameters were examined with the Langmuir probe. A bi-Maxwellian electron distribution was observed near the discharge electrode at a discharge gap of 10 mm, while a Maxwellian distribution was seen near the center. When the discharge gap was 15 mm, electrons had a Maxwellian distribution independent of the position. It was found that there must be a threshold in the discharge gap for stochastic heating to occur. The plasma potential near the discharge electrode was higher than that near the center of the interelectrode gap, suggesting the existence of negative ions. The simulation using the plasma hybrid code was carried out. The spatial profiles of the density and temperature of electrons were similar to the experimental results. The plasma potential had a hill-like profile that was quite different from the measured one. The negative ion density was negligible.

Compact nanomechanical plasmonic phase modulators [Ultracompact nano-mechanical plasmonic phase modulators

DOE PAGES

Dennis, B. S.; Haftel, M. I.; Czaplewski, D. A.; ...

2015-03-30

Highly confined optical energy in plasmonic devices is advancing miniaturization in photonics. However, for mode sizes approaching ≈10 nm, the energy increasingly shifts into the metal, raising losses and hindering active phase modulation. Here, we propose a nanoelectromechanical phase-modulation principle exploiting the extraordinarily strong dependence of the phase velocity of metal–insulator–metal gap plasmons on dynamically variable gap size. We experimentally demonstrate a 23-μm-long non-resonant modulator having a 1.5π rad range, with 1.7 dB excess loss at 780 nm. Analysis shows that by simultaneously decreasing the gap, length and width, an ultracompact-footprint π rad phase modulator can be realized. This ismore » achieved without incurring the extra loss expected for plasmons confined in a decreasing gap, because the increasing phase-modulation strength from a narrowing gap offsets rising propagation losses. Here, such small, high-density electrically controllable components may find applications in optical switch fabrics and reconfigurable plasmonic optics.« less

A Unifying Perspective on Oxygen Vacancies in Wide Band Gap Oxides.

PubMed

Linderälv, Christopher; Lindman, Anders; Erhart, Paul

2018-01-04

Wide band gap oxides are versatile materials with numerous applications in research and technology. Many properties of these materials are intimately related to defects, with the most important defect being the oxygen vacancy. Here, using electronic structure calculations, we show that the charge transition level (CTL) and eigenstates associated with oxygen vacancies, which to a large extent determine their electronic properties, are confined to a rather narrow energy range, even while band gap and the electronic structure of the conduction band vary substantially. Vacancies are classified according to their character (deep versus shallow), which shows that the alignment of electronic eigenenergies and CTL can be understood in terms of the transition between cavity-like localized levels in the large band gap limit and strong coupling between conduction band and vacancy states for small to medium band gaps. We consider both conventional and hybrid functionals and demonstrate that the former yields results in very good agreement with the latter provided that band edge alignment is taken into account.

Growth of Wide Band Gap II-VI Compound Semiconductors by Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Sha, Yi-Gao

1995-01-01

The studies on the crystal growth and characterization of II-VI wide band gap compound semiconductors, such as ZnTe, CdS, ZnSe and ZnS, have been conducted over the past three decades. The research was not quite as extensive as that on Si, III-V, or even narrow band gap II-VI semiconductors because of the high melting temperatures as well as the specialized applications associated with these wide band gap semiconductors. In the past several years, major advances in the thin film technology such as Molecular Beam Epitaxy (MBE) and Metal Organic Chemical Vapor Deposition (MOCVD) have demonstrated the applications of these materials for the important devices such as light-emitting diode, laser and ultraviolet detectors and the tunability of energy band gap by employing ternary or even quaternary systems of these compounds. At the same time, the development in the crystal growth of bulk materials has not advanced far enough to provide low price, high quality substrates needed for the thin film growth technology.

Thickness dependent band gap of Bi{sub 2-x}Sb{sub x}Te{sub 3} (x = 0, 0.05, 0.1) thin films

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

Patel, M. M.; Soni, P. H., E-mail: phsoni-msu@yahoo.com; Desai, C. F.

2016-05-23

Thin films of Bi{sub 2}Te{sub 3}(Sb) were prepared on alkali halide crystal substrates. Sb content and the film thickness were varied. Bi{sub 2}Te{sub 3} is a narrow gap semiconductor. Bi-Sb is a continuous solid solution of substitutional type and Sb therefore was used to test its effect on the band gap. The film thickness variation was also taken up. The infra-red absorption spectra were used in the wave number range 400 cm{sup −1} to 4000 cm{sup −1}. The band gap obtained from the absorption data was found to increase with decreasing thickness since the thickness range used was from 30more » nm to 170 nm. This is a range corresponding to nanostructures and hence quantum size effect was observed as expected. The band gap also exhibited Sb content dependence. The detail results are have been reported and explained.« less

Band gap engineering of N-alloyed Ga{sub 2}O{sub 3} thin films

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

Song, Dongyu; Li, Bingsheng, E-mail: libingsheng@hit.edu.cn, E-mail: ashen@ccny.cuny.edu; Sui, Yu

2016-06-15

The authors report the tuning of band gap of GaON ternary alloy in a wide range of 2.75 eV. The samples were prepared by a two-step nitridation method. First, the samples were deposited on 2-inch fused silica substrates by megnetron sputtering with NH{sub 3} and Ar gas for 60 minutes. Then they were annealed in NH{sub 3} ambience at different temperatures. The optical band gap energies are calculated from transmittance measurements. With the increase of nitridation temperature, the band gap gradually decreases from 4.8 eV to 2.05 eV. X-ray diffraction results indicate that as-deposited amorphous samples can crystallize into monoclinicmore » and hexagonal structures after they were annealed in oxygen or ammonia ambience, respectively. The narrowing of the band gap is attributed to the enhanced repulsion of N2p -Ga3d orbits and formation of hexagonal structure.« less

Convergence in Sleep Time Accomplished? Gender Gap in Sleep Time for Middle-Aged Adults in Korea

PubMed Central

Eun, Ki-Soo

2018-01-01

Although the gender gap in sleep time has narrowed significantly in the last decade, middle-aged women between ages 35 and 60 still sleep less than their male counterparts in Korea. This study examines and provides evidence for factors contributing to the gender gap in this age group. Using Korean Time Use Survey (KTUS) data from 2004, 2009 and 2014, we find that middle-aged women’s difficulty in managing work-life balance and traditional role expectations placed upon women are the main causes of the gender gap in sleep time. The decomposition analysis reveals that the improved socioeconomic status and recent changes in familial expectations for women may have helped them sleep more than in the past. However, there remain fundamental differences in attitude and time use patterns between men and women that prevent middle-aged women from getting the same amount of sleep. PMID:29671824

Convergence in Sleep Time Accomplished? Gender Gap in Sleep Time for Middle-Aged Adults in Korea.

PubMed

Cha, Seung-Eun; Eun, Ki-Soo

2018-04-19

Although the gender gap in sleep time has narrowed significantly in the last decade, middle-aged women between ages 35 and 60 still sleep less than their male counterparts in Korea. This study examines and provides evidence for factors contributing to the gender gap in this age group. Using Korean Time Use Survey (KTUS) data from 2004, 2009 and 2014, we find that middle-aged women’s difficulty in managing work-life balance and traditional role expectations placed upon women are the main causes of the gender gap in sleep time. The decomposition analysis reveals that the improved socioeconomic status and recent changes in familial expectations for women may have helped them sleep more than in the past. However, there remain fundamental differences in attitude and time use patterns between men and women that prevent middle-aged women from getting the same amount of sleep.

Evidence-based medicine, the research-practice gap, and biases in medical and surgical decision making in dermatology.

PubMed

Eaglstein, William H

2010-10-01

The objectives of this article are to promote a better understanding of a group of biases that influence therapeutic decision making by physicians/dermatologists and to raise the awareness that these biases contribute to a research-practice gap that has an impact on physicians and treatment solutions. The literature included a wide range of peer-reviewed articles dealing with biases in decision making, evidence-based medicine, randomized controlled clinical trials, and the research-practice gap. Bias against new therapies, bias in favor of indirect harm or omission, and bias against change when multiple new choices are offered may unconsciously affect therapeutic decision making. Although there is no comprehensive understanding or theory as to how choices are made by physicians, recognition of certain cognition patterns and their associated biases will help narrow the research-practice gap and optimize decision making regarding therapeutic choices.

NEIGHBORHOOD CONTEXT AND THE GENDER GAP IN ADOLESCENT VIOLENT CRIME*

PubMed Central

Zimmerman, Gregory M.; Messner, Steven F.

2011-01-01

Although researchers consistently demonstrate that females engage in less criminal behavior than males across the life course, research on the variability of the gender gap across contexts is sparse. To address this issue, we examine the gender gap in self-reported violent crime among adolescents across neighborhoods. Multilevel models using data from the Project of Human Development in Chicago Neighborhoods (PHDCN) indicate that the gender gap in violent crime decreases as levels of neighborhood disadvantage increase. Further, the narrowing of the gender gap is explained by gender differences in peer influence on violent offending. Neighborhood disadvantage increases exposure to peer violence for both sexes, but peer violence has a stronger impact on violent offending for females than for males, producing the reduction in the gender gap at higher levels of disadvantage. We also find that the gender difference in the relationship between peer violence and offending is explained, in part, by (1) the tendency for females to have more intimate friendships than males, and (2) the moderating effect of peer intimacy on the relationship between peer violence and self-reported violent behavior. PMID:21709751

NEIGHBORHOOD CONTEXT AND THE GENDER GAP IN ADOLESCENT VIOLENT CRIME.

PubMed

Zimmerman, Gregory M; Messner, Steven F

2010-12-01

Although researchers consistently demonstrate that females engage in less criminal behavior than males across the life course, research on the variability of the gender gap across contexts is sparse. To address this issue, we examine the gender gap in self-reported violent crime among adolescents across neighborhoods. Multilevel models using data from the Project of Human Development in Chicago Neighborhoods (PHDCN) indicate that the gender gap in violent crime decreases as levels of neighborhood disadvantage increase. Further, the narrowing of the gender gap is explained by gender differences in peer influence on violent offending. Neighborhood disadvantage increases exposure to peer violence for both sexes, but peer violence has a stronger impact on violent offending for females than for males, producing the reduction in the gender gap at higher levels of disadvantage. We also find that the gender difference in the relationship between peer violence and offending is explained, in part, by (1) the tendency for females to have more intimate friendships than males, and (2) the moderating effect of peer intimacy on the relationship between peer violence and self-reported violent behavior.

The contribution of preterm birth to the Black-White infant mortality gap, 1990 and 2000.

PubMed

Schempf, Ashley H; Branum, Amy M; Lukacs, Susan L; Schoendorf, Kenneth C

2007-07-01

We evaluated whether the decline of the racial disparity in preterm birth during the last decade was commensurate with a decline in the contribution of preterm birth to the infant mortality gap. We used linked files of 1990 and 2000 data on US infant births and deaths to partition the gap between Black and White infant mortality rates into differences in the (1) distribution of gestational age and (2) gestational age-specific mortality rates. Between 1990 and 2000, the Black-White infant mortality rate ratio did not change significantly (2.3 vs 2.4). Excess deaths among preterm Black infants accounted for nearly 80% of the Black-White infant mortality gap in both 1990 and 2000. The narrowing racial disparity in the preterm birth rate was counterbalanced by greater mortality reductions in White than in Black preterm infants. Extremely preterm birth (<28 weeks) was 4 times higher in Black infants and accounted for more than half of the infant mortality gap. Substantial reductions in the Black-White infant mortality gap will require improved prevention of extremely preterm birth among Black infants.

Band gap engineering of BC2N for nanoelectronic applications

NASA Astrophysics Data System (ADS)

Lim, Wei Hong; Hamzah, Afiq; Ahmadi, Mohammad Taghi; Ismail, Razali

2017-12-01

The BC2N as an example of boron-carbon-nitride (BCN), has the analogous structure as the graphene and boron nitride. It is predicted to have controllable electronic properties. Therefore, the analytical study on the engineer-able band gap of the BC2N is carried out based on the schematic structure of BC2N. The Nearest Neighbour Tight Binding (NNTB) model is employed with the dispersion relation and the density of state (DOS) as the main band gap analysing parameter. The results show that the hopping integrals having the significant effect on the band gap, band structure and DOS of BC2N nanowire (BC2NNW) need to be taken into consideration. The presented model indicates consistent trends with the published computational results around the Dirac points with the extracted band gap of 0.12 eV. Also, it is distinguished that wide energy gap of boron nitride (BN) is successfully narrowed by this carbon doped material which assures the application of BC2N on the nanoelectronics and optoelectronics in the near future.

77 FR 47363 - Narrow Woven Ribbons With Woven Selvedge From the People's Republic of China: Preliminary Results...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

..., polyester, rayon, polypropylene, and polyethylene teraphthalate), metal threads and/or metalized yarns, or... original length as defined in the (HTSUS, Section XI, Note 13) or rubber thread; (4) Narrow woven ribbons... comprised at least 85 percent by weight of threads having a denier of 225 or higher; (9) Narrow woven...

Comparative study on Ga1-xZnxN1-yOy oxynitride synthesized by different techniques for application in photocatalytic hydrogen production

NASA Astrophysics Data System (ADS)

Menon, Sumithra Sivadas; Baskar, K.; Singh, Shubra

2017-06-01

Hydrogen evolution by overall water splitting has emerged as a potential method for green energy generation due to the introduction of highly efficient photocatalysts active under visible region of spectra. In the present work, we focus on a comparative study of the properties of Ga1-xZnxN1-yOy oxynitride samples synthesized by two techniques and their effect on the sample properties. The samples were prepared by both traditional nitridation technique and solution combustion method. Room temperature photoluminescence studies revealed the introduction of additional energy levels above the valence band which in turns broadens the valence band and subsequently reduces the band gap. The band gap narrowing was further confirmed using diffuse reflectance spectroscopy and Valence band X-ray photoelectron spectroscopy (VB-XPS). It was also realized from VB XPS that the reduction of band gap in both the samples was due to upshift of valence band without affecting the conduction band. The presence of disorder activated modes in the samples was examined using temperature dependent Raman spectroscopy. In this work we corroborate the theoretical prediction reported by Al-Jassim et. al that the bandgap narrowing mechanism in ZnO rich solid solution and GaN rich solid solution is asymmetric and a significant bandgap reduction could be observed for ZnO rich solid solution than GaN rich.

Narrowing the Transfer Gap: The Advantages of "as if" Situations in Training.

ERIC Educational Resources Information Center

Vermeulen, Rita C. M.

2002-01-01

A schema a frame creates context and shapes interpretation. Using an "as if" framework can connect the contexts of training and job performance to improve transfer. Techniques that create "as if" situations include role playing, visualization, psychodrama, voice dialogue, improvisation, playback theatre, and six-steps reframing. (Contains 23…

Narrowing the Skills Gap: Workplace Literacy Programs in Canada. Final Report.

ERIC Educational Resources Information Center

Ottawa Univ. (Ontario).

This report documents, in case study format, eight workplace literacy programs in Canada. Introductory materials highlight conclusions and discuss reasons for undertaking the project to document the Canadian experience in basic skills training from the perspective of the employer and employee and program design. Each case study or program profile…

The Impact of Rosenwald Schools on Black Achievement. WP 2009-26

ERIC Educational Resources Information Center

Aaronson, Daniel; Mazumder, Bhashkar

2009-01-01

The Black-White gap in completed schooling among Southern born men narrowed sharply between the World Wars after being stagnant from 1880 to 1910. We examine a large scale school construction project, the Rosenwald Rural Schools Initiative, which was designed to dramatically improve the educational opportunities for Southern rural Blacks. From…

The Evolution of Macroeconomic Theory and Implications for Teaching Intermediate Macroeconomics.

ERIC Educational Resources Information Center

Froyen, Richard T.

1996-01-01

Traces the development of macroeconomic theory from John Maynard Keynes to modern endogenous growth theory. Maintains that a combination of interest in growth theory and related policy questions will play a prominent role in macroeconomics in the future. Recommends narrowing the gap between graduate school and undergraduate economics instruction.…

Spectators or Patriots? Citizens in the Information Age

ERIC Educational Resources Information Center

Dhawan, Amrita

2016-01-01

In theory, a strong democracy rests on robust citizen participation. The practice in most democracies is quite different. This gap presents a challenge, which can be narrowed by augmenting civic education to bring it up to date with the current information environment and thus give citizens the opportunity to participate. Robert Dahl's work on…

Do Some Schools Narrow the Gap? Differential School Effectiveness Revisited

ERIC Educational Resources Information Center

Strand, Steve

2016-01-01

Relatively little research has explored whether schools differ in their effectiveness for different group of pupils (e.g. by ethnicity, poverty or gender), for different curriculum subjects (e.g. English, mathematics or science) or over time (different cohorts). This paper uses multilevel modelling to analyse the national test results at age 7 and…

Basic Research Plan.

DTIC Science & Technology

1996-05-01

detection, catalysts for enhancing and controlling energetic reactions, synthesis of new compounds (e.g., narrow band-gap materials and non-linear...design for synthesis of advanced materials Fabricate porous lightweight and resilient structural materials with novel properties and uses Demonstrate...elements for 10 nm computer memory elements Demonstrate enhanced propellants and explosives with nanoparticle surface chemistry Demonstrate sensing of

Talk to Me, Baby! How You Can Support Young Children's Language Development

ERIC Educational Resources Information Center

Bardige, Betty S.

2009-01-01

Playful, engaging talk with young children is much more than a social activity: it's the foundation of language, intellectual, and social-emotional development, and it's also the key to narrowing the achievement gap between children from different socioeconomic backgrounds. Now there's a practical, easy-to-read guidebook that shows professionals…

Climate Change: Providing Equitable Access to a Rigorous and Engaging Curriculum

ERIC Educational Resources Information Center

Cardichon, Jessica; Roc, Martens

2013-01-01

This report examines how implementing rigorous and engaging curriculum aligned with college- and career-ready standards fosters positive school climates in which students are motivated to succeed, achievement gaps narrow, and learning and outcomes improve. It includes federal, state, and local recommendations for increasing access to high-quality,…

Personalized Surgical Risk Assessment Using Population-Based Data Analysis

ERIC Educational Resources Information Center

AbuSalah, Ahmad Mohammad

2013-01-01

The volume of information generated by healthcare providers is growing at a relatively high speed. This tremendous growth has created a gap between knowledge and clinical practice that experts say could be narrowed with the proper use of healthcare data to guide clinical decisions and tools that support rapid information availability at the…

Design-Based Research within the Constraints of Practice: AlgebraByExample

ERIC Educational Resources Information Center

Booth, Julie L.; Cooper, Laura A.; Donovan, M. Suzanne; Huyghe, Alexandra; Koedinger, Kenneth R.; Paré-Blagoev, E. Juliana

2015-01-01

Superintendents from districts in the Minority Student Achievement Network (MSAN) challenged the Strategic Education Research Partnership (SERP) to identify an approach to narrowing the minority student achievement gap in Algebra 1 without isolating minority students for intervention. SERP partnered with 8 MSAN districts and researchers from 3…

Roadblocks to Integrating Technology into Classroom Instruction

ERIC Educational Resources Information Center

Knight, Courteney Lester

2012-01-01

Although research has concluded that technology can enhance the teaching and learning processes, teachers have not yet fully adopted technology to support their teaching methodologies. In the last decade or so, as the accessible gap narrowed, the focus switched to other factors. This study attempts to answer the question: Why teachers do not fully…

Heat exchanger device and method for heat removal or transfer

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

Koplow, Jeffrey P

2015-03-24

Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

Heat exchanger device and method for heat removal or transfer

DOEpatents

Koplow, Jeffrey P [San Ramon, CA

2012-07-24

Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

Heat exchanger device and method for heat removal or transfer

DOEpatents

Koplow, Jeffrey P

2013-12-10

Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

RTT Goals Challenge Recipients

ERIC Educational Resources Information Center

McNeil, Michele

2011-01-01

Ambitious student-achievement targets turn up the heat, as winners of the $4 billion federal grant effort push to deliver. Winners of the $4 billion Race to the Top jackpot committed to grand goals in using the federal grants to raise student achievement, as measured by higher test scores, narrowed achievement gaps, and increased graduation and…

Narrowing the Achievement Gap in Science.

ERIC Educational Resources Information Center

Koba, Susan B.

1996-01-01

An inner-city Omaha high school created an untracked, wholly desegregated 2-year thematic science curriculum for all 9th and 10th graders. Under the outdoor community study theme, students participate in a simulated archaeological dig of an Omaha Indian earth lodge, study the school grounds' ecological status, and design areas along a proposed…

Narrow gap laser welding

DOEpatents

Milewski, John O.; Sklar, Edward

1998-01-01

A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables.

Narrow gap laser welding

DOEpatents

Milewski, J.O.; Sklar, E.

1998-06-02

A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables. 34 figs.

Creating a Better Funding System for Michigan

ERIC Educational Resources Information Center

Quinn, Daniel

2010-01-01

In 1994, Michigan voters approved a ballot initiative that transferred the power in Michigan's education system from local communities to the state. Proposal A succeeded in slowing the growth of local property taxes and narrowing the gap between the richest and poorest districts in Michigan. However, due to a decade of sluggish economic growth,…

"Making Time for What Matters Most." I3 Development Project: Year 5 Evaluation Report

ERIC Educational Resources Information Center

Donahue, Tara; Ho, Hsiang-Yah; Knotts, Ashli

2015-01-01

The purpose of this study evaluates the work completed in the "Jefferson County Public Schools" (JCPS) project, "Making Time for What Matters Most", aiming to improve student achievement, narrow achievement gaps, strengthen students' college readiness skills, and increase the percentages of students who graduate and go on to…

Exploiting genotyping by sequencing to characterize the genomic structure of the American cranberry through high-density linkage mapping

USDA-ARS?s Scientific Manuscript database

The application of genotyping by sequencing (GBS) approaches, combined with data imputation methodologies, is narrowing the genetic knowledge gap between major and understudied, minor crops. GBS is an excellent tool to characterize the genomic structure of recently domesticated (~200 years) and unde...

Narrowing the Gap Between the Rhetoric and the Reality of Medical Ethics.

ERIC Educational Resources Information Center

Silverman, David R.

1996-01-01

This paper argues that in the debate over medical ethics and its role in medical education, the divergence of law and reality reflects the law's flawed medical model, which poorly matches the dynamic of the physician-patient relationship and attempts ineffectually to reshape it, and also medicine's autonomous professional culture, which…

Human Capital Development in Education: Challenges and Policy Options

ERIC Educational Resources Information Center

Best, Jane R.

2010-01-01

Increasing student achievement and narrowing the achievement gap are challenges that states and districts continue to confront as they strive to develop talent that will contribute to our nation's economy. Some strategies to produce authentic improvement in learning are not entirely a mystery. A preponderance of research in recent years provides…

Supporting Oral Narrative Development of Kindergarten English Language Learners Using Multimedia Stories

ERIC Educational Resources Information Center

Yang, Sha

2016-01-01

Narrative ability comes before literacy for bilingual students and helps narrow down the gap in text-level literacy between English language learners (ELLs) and native English speakers. Kindergarten ELLs are the best age group to receive intervention to improve their oral narrative skills. Multimedia stories have potential to assist kindergarten…

Heat exchanger device and method for heat removal or transfer

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

Koplow, Jeffrey P.

2015-12-08

Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

Closing the Gap. SREB Program Blends Academic Standards, Vocational Courses.

ERIC Educational Resources Information Center

Bottoms, Gene

1992-01-01

Southern Regional Education Board's State Vocational Education Consortium developed a model for integrating vocational and academic education that includes at least three credits each in math and science; four English courses; and four credits in a vocational major and two in related fields. Eight sites implementing the model have narrowed gap…

The Learning Connection: New Partnerships between Schools and Colleges.

ERIC Educational Resources Information Center

Maeroff, Gene I., Ed.; Callan, Patrick M., Ed.; Usdan, Michael D., Ed.

The educational chasm between schools and colleges is an indication of dysfunction. It is becoming increasingly recognized as a major impediment to the successful education of all students. High standards and improved schools and colleges will ultimately depend on the extent to which this gap is narrowed. This book describes 12 programs that are…

Foreign Language Learners' Beliefs about CALL: The Case of a U.S. Midwestern University

ERIC Educational Resources Information Center

Sydorenko, Tetyana; Hsieh, Ching-Ni; Ahn, Seongmee; Arnold, Nike

2017-01-01

A significant body of research has examined language learners' attitudes toward particular technologies used in foreign language classrooms. However, literature is scarce on foreign language learners' beliefs toward computer-assisted language learning (CALL) in general. To narrow this gap, we investigated the constructs that compose a system of…

Uncovering "Threshold Concepts" in Web Development: An Instructor Perspective

ERIC Educational Resources Information Center

Alston, Peter; Walsh, David; Westhead, Gary

2015-01-01

The field of Web development has evolved and diversified significantly in recent years, and narrowing the gap between the requirements of academia and the demands of industry remains a challenge. Moreover, many faculty members often struggle with knowing "how much" of a particular subject they should teach to their students and at what…

ThinkeringSpace: Designing for Collaboration

ERIC Educational Resources Information Center

Moura, Heloisa; Fahnstrom, Dale; Prygrocki, Greg; McLeish, T. J.

2009-01-01

Innovation, collaboration and system thinking are increasingly recognized as skills that can be useful to children, and that can help ensure their success as citizens and workers in the 21st century Seeking to improve opportunities for young people to develop abilities and competencies for the future and to narrow the complexity gap left by No…

Drastic effect of the Mn-substitution in the strongly correlated semiconductor FeSb2.

NASA Astrophysics Data System (ADS)

Kassem, Mohamed A.; Tabata, Yoshikazu; Waki, Takeshi; Nakamura, Hiroyuki

2017-06-01

We report the effects of Mn substitution, corresponding to hole doping, on the electronic properties of the narrow gap semiconductor, FeSb2, using single crystals of Fe1- x Mn x Sb2 grown by the Sb flux method. The orthorhombic Pnnm structure was confirmed by powder X-ray diffraction (XRD) for the pure and Mn-substituted samples. Their crystal structure parameters were refined using the Rietveld method. The chemical composition was investigated by wavelength-dispersive X-ray spectroscopy (WDX). The solubility limit of Mn in FeSb2 is x max ˜ 0.05 and the lattice constants change monotonically with increasing the actual Mn concentration. A drastic change from semiconducting to metallic electronic transports was found at very low Mn concentration at x ˜ 0.01. Our experimental results and analysis indicate that the substitution of a small amount of Mn changes drastically the electronic state in FeSb2 as well as the Co-substitution does: closing of the narrow gap and emergence of the density of states (DOS) at the Fermi level.

Design Improvements and X-Ray Performance of a Time Projection Chamber Polarimeter for Persistent Astronomical Sources

NASA Technical Reports Server (NTRS)

Hill, Joanne E.; Black, J. Kevin; Emmett, Thomas J.; Enoto, Teruaki; Jahoda, Keith M.; Kaaret, Philip; Nolan, David S.; Tamagawa, Toru

2014-01-01

The design of the Time-Projection Chamber (TPC) Polarimeter for the Gravity and Extreme Magnetism Small Explorer (GEMS) was demonstrated to Technology Readiness Level 6 (TRL-6)3 and the flight detectors fabricated, assembled and performance tested. A single flight detector was characterized at the Brookhaven National Laboratory Synchrotron Light Source with polarized X-rays at 10 energies from 2.3-8.0 keV at five detector positions. The detector met all of the GEMS performance requirements. Lifetime measurements have shown that the existing flight design has 23 years of lifetime4, opening up the possibility of relaxing material requirements, in particular the consideration of the use of epoxy, to reduce risk elsewhere. We report on design improvements to the GEMS detector to enable a narrower transfer gap that, when operated with a lower transfer field, reduces asymmetries in the detector response. In addition, the new design reduces cost and risk by simplifying the assembly and reducing production time. Finally, we report on the performance of the narrow-gap detector in response to polarized and unpolarized X-rays.

Distinguishing triplet energy transfer and trap-assisted recombination in multi-color organic light-emitting diode with an ultrathin phosphorescent emissive layer

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

Xue, Qin, E-mail: xueqin19851202@163.com; Liu, Shouyin; Xie, Guohua

2014-03-21

An ultrathin layer of deep-red phosphorescent emitter tris(1-phenylisoquinoline) iridium (III) (Ir(piq){sub 3}) is inserted within different positions of the electron blocking layer fac-tris (1-phenylpyrazolato-N,C{sup 2′})-iridium(III) (Ir(ppz){sub 3}) to distinguish the contribution of the emission from the triplet exciton energy transfer/diffusion from the adjacent blue phosphorescent emitter and the trap-assisted recombination from the narrow band-gap emitter itself. The charge trapping effect of the narrow band-gap deep-red emitter which forms a quantum-well-like structure also plays a role in shaping the electroluminescent characteristics of multi-color organic light-emitting diodes. By accurately controlling the position of the ultrathin sensing layer, it is considerably easy tomore » balance the white emission which is quite challenging for full-color devices with multiple emission zones. There is nearly no energy transfer detectable if 7 nm thick Ir(ppz){sub 3} is inserted between the blue phosphorescent emitter and the ultrathin red emitter.« less

Narrow Energy Gap between Triplet and Singlet Excited States of Sn2+ in Borate Glass

PubMed Central

Masai, Hirokazu; Yamada, Yasuhiro; Suzuki, Yuto; Teramura, Kentaro; Kanemitsu, Yoshihiko; Yoko, Toshinobu

2013-01-01

Transparent inorganic luminescent materials have attracted considerable scientific and industrial attention recently because of their high chemical durability and formability. However, photoluminescence dynamics of ns2-type ions in oxide glasses has not been well examined, even though they can exhibit high quantum efficiency. We report on the emission property of Sn2+-doped strontium borate glasses. Photoluminescence dynamics studies show that the peak energy of the emission spectrum changes with time because of site distribution of emission centre in glass. It is also found that the emission decay of the present glass consists of two processes: a faster S1-S0 transition and a slower T1-S0 relaxation, and also that the energy difference between T1 and S1 states was found to be much smaller than that of (Sn, Sr)B6O10 crystals. We emphasize that the narrow energy gap between the S1 and T1 states provides the glass phosphor a high quantum efficiency, comparable to commercial crystalline phosphors. PMID:24345869

Suspended few-layer graphene beam electromechanical switch with abrupt on-off characteristics and minimal leakage current

NASA Astrophysics Data System (ADS)

Kim, Sung Min; Song, Emil B.; Lee, Sejoon; Seo, Sunae; Seo, David H.; Hwang, Yongha; Candler, R.; Wang, Kang L.

2011-07-01

Suspended few-layer graphene beam electro-mechanical switches (SGSs) with 0.15 μm air-gap are fabricated and electrically characterized. The SGS shows an abrupt on/off current characteristics with minimal off current. In conjunction with the narrow air-gap, the outstanding mechanical properties of graphene enable the mechanical switch to operate at a very low pull-in voltage (VPI) of 1.85 V, which is compatible with conventional complimentary metal-oxide-semiconductor (CMOS) circuit requirements. In addition, we show that the pull-in voltage exhibits an inverse dependence on the beam length.

Enhanced photo-catalytic activity of Sr and Ag co-doped TiO2 nanoparticles for the degradation of Direct Green-6 and Reactive Blue-160 under UV & visible light.

PubMed

Naraginti, Saraschandra; Thejaswini, T V L; Prabhakaran, D; Sivakumar, A; Satyanarayana, V S V; Arun Prasad, A S

2015-10-05

This work is focused on sol-gel synthesis of silver and strontium co-doped TiO2 nanoparticles and their utilization as photo-catalysts in degradation of two textile dyes. Effect of pH, intensity of light, amount of photo-catalyst, concentration of dye, sensitizers, etc., were studied to optimize conditions for obtaining enhanced photo-catalytic activity of synthesized nanoparticles. XRD, BET, HR-TEM, EDAX and UV-Vis (diffused reflectance mode) techniques were used to characterize the nanoparticles. Interestingly, band gap of Sr and Ag co-doped TiO2 nanoparticles showed considerable narrowing (2.6 eV) when compared to Ag doped TiO2 (2.7 eV) and undoped TiO2 (3.17 eV) nanoparticles. Incorporation of Ag and Sr in the lattice of TiO2 could bring isolated energy levels near conduction and valence bands thus narrowing band gap. The XRD analysis shows that both Ag and Sr nanoparticles are finely dispersed on the surface of titania framework, without disturbing its crystalline structure. TEM images indicate that representative grain sizes of Ag-doped TiO2 & Sr and Ag co-doped TiO2 nanoparticles are in the range of 8-20 nm and 11-25 nm, respectively. Effective degradation of Direct Green-6 (DG-6) and Reactive Blue-160 (RB-160) under UV and visible light has been achieved using the photo-catalysts. Sr and Ag co-doped TiO2 photo-catalysts showed higher catalytic activity during degradation process in visible region when compared to Ag-doped and undoped TiO2 nanoparticles which could be attributed to the interactive effect caused by band gap narrowing and enhancement in charge separation. For confirming degradation of the dyes, total organic carbon (TOC) content was monitored periodically. Copyright © 2015 Elsevier B.V. All rights reserved.

Narrow-gap physical vapour deposition synthesis of ultrathin SnS1-xSex (0 ≤ x ≤ 1) two-dimensional alloys with unique polarized Raman spectra and high (opto)electronic properties.

PubMed

Gao, Wei; Li, Yongtao; Guo, Jianhua; Ni, Muxun; Liao, Ming; Mo, Haojie; Li, Jingbo

2018-05-10

Here we report ultrathin SnS1-xSex alloyed nanosheets synthesized via a narrow-gap physical vapour deposition approach. The SnS1-xSex alloy presents a uniform quadrangle shape with a lateral size of 5-80 μm and a thickness of several nanometers. Clear orthorhombic symmetries and unique in-plane anisotropic properties of the 2D alloyed nanosheets were found with the help of X-ray diffraction, high resolution transmission electron microscopy and polarized Raman spectroscopy. Moreover, 2D alloyed field-effect transistors were fabricated, exhibiting a unipolar p-type semiconductor behavior. This study also provided a lesson that the thickness of the alloyed channels played the major role in the current on/off ratio, and the high ratio of 2.10 × 102 measured from a large ultrathin SnS1-xSex device was two orders of magnitude larger than that of previously reported SnS, SnSe nanosheet based transistors because of the capacitance shielding effect. Obviously enhanced Raman peaks were also found in the thinner nanosheets. Furthermore, the ultrathin SnS0.5Se0.5 based photodetector showed a highest responsivity of 1.69 A W-1 and a short response time of 40 ms under illumination of a 532 nm laser from 405 to 808 nm. Simultaneously, the corresponding highest external quantum efficiency of 392% and detectivity of 3.96 × 104 Jones were also achieved. Hopefully, the narrow-gap synthesis technique provides us with an improved strategy to obtain large ultrathin 2D nanosheets which may tend to grow into thicker ones for stronger interlayer van der Waals forces, and the enhanced physical and (opto)electrical performances in the obtained ultrathin SnS1-xSex alloyed nanosheets prove their great potential in the future applications for versatile devices.

Time Trends and Policy Gaps: The Case of Alcohol Misuse Among Adolescents in Lebanon

PubMed Central

Ghandour, Lilian; Afifi, Rima; Fares, Sonia; El Salibi, Noura; Rady, Alissar

2017-01-01

Background Monitoring studies are crucial for informing and reforming local policies. Objectives Using the Lebanon 2005 and 2011 Global School-based Student Health Surveys (GSHS), alcohol time trends were described, policy gaps were identified, and harm reduction policy recommendations were made. Methods In 2005 and 2011, 100 (n = 5109 students) and 44 (n = 2784 students) middle schools were surveyed, respectively. Self-reported cross-sectional data on alcohol use among 7–9th graders in private and public schools was collected including 30-day prevalence, lifetime drunkenness, alcohol-related problems, and sources of alcohol. Results In 2011, the majority (87%) had alcohol before turning 14. Between 2005 and 2011, past 30-day alcohol use had increased by 40% and lifetime drunkenness by 50% in the total sample (122% among females with a narrowing in the gender gap). Drinking was regular for more than a third of the past 30-day drinkers (drank two or more drinks on the days they drank). Male adolescents were more likely to obtain alcohol from “stores” or “through their friends” whereas females’ main source was their “family.” One in twenty reported experiencing alcohol-related problems (e.g., getting into fights with family/friends and skipping school). Conclusion/Importance Evidence-informed policy implications include enforcing a minimum legal drinking age, regulating alcohol advertising, and marketing particularly those targeting youth and women, and ensuring the availability of youth-friendly services. Public messages to increase awareness among all stakeholders including youth, their parents, and larger community are also needed. PMID:26646475

75 FR 10503 - Notice of Lodging of Consent Decree Under the Clean Air Act

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-08

... DEPARTMENT OF JUSTICE Notice of Lodging of Consent Decree Under the Clean Air Act Notice is hereby... alleged violations of the Clean Air Act at the DEGs of Narrows, LLC facility in Narrows, Virginia. The complaint alleged that DEGs of Narrows, LLC violated the Clean Air Act, Sections 110, 112 and 502 of the CAA...

Photonic gaps in cholesteric elastomers under deformation

NASA Astrophysics Data System (ADS)

Cicuta, P.; Tajbakhsh, A. R.; Terentjev, E. M.

2004-07-01

Cholesteric liquid crystal elastomers have interesting and potentially very useful photonic properties. In an ideal monodomain configuration of these materials, one finds a Bragg reflection of light in a narrow wavelength range and a particular circular polarization. This is due to the periodic structure of the material along one dimension. In many practical cases, the cholesteric rubber possesses a sufficient degree of quenched disorder, which makes the selective reflection broadband. We investigate experimentally the problem of how the transmittance of light is affected by mechanical deformation of the elastomer, and the relation to changes in liquid crystalline structure. We explore a series of samples which have been synthesized with photonic stop gaps across the visible range. This allows us to compare results with detailed theoretical predictions regarding the evolution of stop gaps in cholesteric elastomers.

Visible-light absorption and large band-gap bowing of GaN 1-xSb x from first principles

DOE PAGES

Sheetz, R. Michael; Richter, Ernst; Andriotis, Antonis N.; ...

2011-08-01

Applicability of the Ga(Sb x)N 1-x alloys for practical realization of photoelectrochemical water splitting is investigated using first-principles density functional theory incorporating the local density approximation and generalized gradient approximation plus the Hubbard U parameter formalism. Our calculations reveal that a relatively small concentration of Sb impurities is sufficient to achieve a significant narrowing of the band gap, enabling absorption of visible light. Theoretical results predict that Ga(Sb x)N 1-x alloys with 2-eV band gaps straddle the potential window at moderate to low pH values, thus indicating that dilute Ga(Sb x)N 1-x alloys could be potential candidates for splitting watermore » under visible light irradiation.« less

A multi-scale segmentation approach to filling gaps in Landsat ETM+ SLC-off images

USGS Publications Warehouse

Maxwell, S.K.; Schmidt, Gail L.; Storey, James C.

2007-01-01

On 31 May 2003, the Landsat Enhanced Thematic Plus (ETM+) Scan Line Corrector (SLC) failed, causing the scanning pattern to exhibit wedge-shaped scan-to-scan gaps. We developed a method that uses coincident spectral data to fill the image gaps. This method uses a multi-scale segment model, derived from a previous Landsat SLC-on image (image acquired prior to the SLC failure), to guide the spectral interpolation across the gaps in SLC-off images (images acquired after the SLC failure). This paper describes the process used to generate the segment model, provides details of the gap-fill algorithm used in deriving the segment-based gap-fill product, and presents the results of the gap-fill process applied to grassland, cropland, and forest landscapes. Our results indicate this product will be useful for a wide variety of applications, including regional-scale studies, general land cover mapping (e.g. forest, urban, and grass), crop-specific mapping and monitoring, and visual assessments. Applications that need to be cautious when using pixels in the gap areas include any applications that require per-pixel accuracy, such as urban characterization or impervious surface mapping, applications that use texture to characterize landscape features, and applications that require accurate measurements of small or narrow landscape features such as roads, farmsteads, and riparian areas.

The role of intraoperative narrow-band imaging in transoral laser microsurgery for early and moderately advanced glottic cancer.

PubMed

Klimza, Hanna; Jackowska, Joanna; Piazza, Cesare; Banaszewski, Jacek; Wierzbicka, Malgorzata

2018-03-01

Trans-oral laser microsurgery is an established technique for the treatment of early and moderately advanced laryngeal cancer. The authors intend to test the usefulness of narrow-band imaging in the intraoperative assessment of the larynx mucosa in terms of specifying surgical margins. Forty-four consecutive T1-T2 glottic cancers treated with trans-oral laser microsurgery Type I-VI cordectomy were presented. Suspected areas (90 samples/44 patients) were biopsied under the guidance of narrow-band imaging and white light and sent for frozen section. Our study revealed that 75 of 90 (83.3%) white light and narrow-band imaging-guided samples were histopathologically positive: 30 (40%) were confirmed as carcinoma in situ or invasive carcinoma and 45 (60%) as moderate to severe dysplasia. In 6 patients mucosa was suspected only in narrow-band imaging, with no suspicion under white light. Thus, in these 6 patients 18/90 (20%) samples were taken. In 5/6 patients 16/18 (88.8%) samples were positive in frozen section: in 6/18 (33.3%) carcinoma (2 patients), 10/18 (66.6%) severe dysplasia was confirmed (3 patients). In 1 patient 2/18 (11.1%) samples were negative in frozen section. Presented analysis showed, that sensitivity, specificity and accuracy of white light was 79.5%, 20% and 71.1% respectively, while narrow-band imaging was 100%, 0.0% and 85.7%, respectively. The intraoperative use of narrow-band imaging proved to be valuable in the visualization of suspect areas of the mucosa. Narrow-band imaging confirms the suspicions undertaken in white light and importantly, it showed microlesions beyond the scope of white light. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Electronic structures of anatase (TiO2)1-x(TaON)x solid solutions: a first-principles study.

PubMed

Dang, Wenqiang; Chen, Hungru; Umezawa, Naoto; Zhang, Junying

2015-07-21

Sensitizing wide band gap photo-functional materials under visible-light irradiation is an important task for efficient solar energy conversion. Although nitrogen doping into anatase TiO2 has been extensively studied for this purpose, it is hard to increase the nitrogen content in anatase TiO2 because of the aliovalent nitrogen substituted for oxygen, leading to the formation of secondary phases or defects that hamper the migration of photoexcited charge carriers. In this paper, electronic structures of (TiO2)1-x(TaON)x (0 ≤ x ≤ 1) solid solutions, in which the stoichiometry is satisfied with the co-substitution of Ti for Ta along with O for N, are investigated within the anatase crystal structure using first-principles calculations. Our computational results show that the solid solutions have substantially narrower band gaps than TiO2, without introducing any localized energy states in the forbidden gap. In addition, in comparison with the pristine TiO2, the solid solution has a direct band gap when the content of TaON exceeds 0.25, which is advantageous to light absorption. The valence band maximum (VBM) of the solid solutions, which is mainly composed of N 2p states hybridized with O 2p, Ti 3d or Ta 5d orbitals, is higher in energy than that of pristine anatase TiO2 consisting of non-bonding O 2p states. On the other hand, incorporating TaON into TiO2 causes the formation of d-d bonding states through π interactions and substantially lowers the conduction band minimum (CBM) because of the shortened distance between some metal atoms. As a result, the anatase (TiO2)1-x(TaON)x is expected to become a promising visible-light absorber. In addition, some atomic configurations are found to possess exceptionally narrow band gaps.

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.

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

Aliev, Ziya S., E-mail: ziyasaliev@gmail.com; Institute of Physics, ANAS, H.Javid ave. 131, AZ1143 Baku; Donostia International Physics Center

Single crystals of the ternary copper compounds CuTlS and CuTlSe have been successfully grown from stoichiometric melt by using vertical Bridgman-Stockbarger method. The crystal structure of the both compounds has been determined by powder and single crystal X-Ray diffraction. They crystallize in the PbFCl structure type with two formula units in the tetragonal system, space group P4/nmm, a=3.922(2); c=8.123(6); Z=2 and a=4.087(6); c=8.195(19) Å; Z=2, respectively. The band structure of the reported compounds has been analyzed by means of full-potential linearized augmented plane-wave (FLAPW) method based on the density functional theory (DFT). Both compounds have similar band structures and aremore » narrow-gap semiconductors with indirect band gap. The resistivity measurements agree with a semiconductor behavior although anomalies are observed at low temperature. - Graphical abstract: The crystal structures of CuTl and CuTlSe are isostructural with the PbFCl-type and the superconductor LiFeAs-type tetragonal structure. The band structure calculations confirmed that they are narrow-gap semiconductors with indirect band gaps of 0.326 and 0.083 eV. The resistivity measurements, although confirming the semiconducting behavior of both compounds exhibit unusual anomalies at low temperatures. - Highlights: • Single crystals of CuTlS and CuTlSe have been successfully grown by Bridgman-Stockbarger method. • The crystal structure of the both compounds has been determined by single crystal XRD. • The band structure of the both compounds has been analyzed based on the density functional theory (DFT). • The resistivity measurements have been carried out from room temperature down to 10 K.« less

Yb5Ga2Sb6: a mixed valent and narrow-band gap material in the RE5M2X6 family.

PubMed

Subbarao, Udumula; Sarkar, Sumanta; Gudelli, Vijay Kumar; Kanchana, V; Vaitheeswaran, G; Peter, Sebastian C

2013-12-02

A new compound Yb5Ga2Sb6 was synthesized by the metal flux technique as well as high frequency induction heating. Yb5Ga2Sb6 crystallizes in the orthorhombic space group Pbam (no. 55), in the Ba5Al2Bi6 structure type, with a unit cell of a = 7.2769(2) Å, b = 22.9102(5) Å, c = 4.3984(14) Å, and Z = 2. Yb5Ga2Sb6 has an anisotropic structure with infinite anionic double chains (Ga2Sb6)(10-) cross-linked by Yb(2+) and Yb(3+) ions. Each single chain is made of corner-sharing GaSb4 tetrahedra. Two such chains are bridged by Sb2 groups to form double chains of 1/∞ [Ga2Sb6(10-)]. The compound satisfies the classical Zintl-Klemm concept and is a narrow band gap semiconductor with an energy gap of around 0.36 eV calculated from the electrical resistivity data corroborating with the experimental absorption studies in the IR region (0.3 eV). Magnetic measurements suggest Yb atoms in Yb5Ga2Sb6 exist in the mixed valent state. Temperature dependent magnetic susceptibility data follows the Curie-Weiss behavior above 100 K and no magnetic ordering was observed down to 2 K. Experiments are accompanied by all electron full-potential linear augmented plane wave (FP-LAPW) calculations based on density functional theory to calculate the electronic structure and density of states. The calculated band structure shows a weak overlap of valence band and conduction band resulting in a pseudo gap in the density of states revealing semimetallic character.

Focus on Teacher Salaries: Update for 1998-99.

ERIC Educational Resources Information Center

Gaines, Gale F.

For the third consecutive year, Southern Regional Education Board (SREB) states narrowed the gap between national average teacher salaries and the region's average. The regional average for 1998-99 was 88.2 percent of the national average. A year earlier, it was 87.3 percent of the national average. The average increase for SREB states was 4…

An Investigation of No Child Left Behind and Its Primary Purpose to Close the Achievement Gap

ERIC Educational Resources Information Center

Holmes, Shaun L.

2012-01-01

Research has suggested the 2001 No Child Left Behind high-stakes testing legislation has resulted in a narrowed curriculum, decreased opportunities for poor and minority students, and decreased job satisfaction among teachers and administrators. Given the considerably negative influence No Child Left Behind legislation has had on public education,…

Team Learning to Narrow the Gap between Healthcare Knowledge and Practice

ERIC Educational Resources Information Center

Anand, Tejwansh S.

2014-01-01

This study explored team-based learning in teams of healthcare professionals working on making meaning of evidence-based clinical guidelines in their field to apply them within their practice setting. The research based team learning models posited by Kasl, Marsick, and Dechant (1997) and Edmondson, Dillon, and Roloff (2007) were used as the…

An Equitable Balance: Designing Quality Thinking Systems in Art Education

ERIC Educational Resources Information Center

Ingalls Vanada, Delane

2016-01-01

Dynamic learning environments in the arts that nurture all students' capacities for deep meaning, synthesis and connection-making have the best chance of standing in the gap toward educational justice. New paradigms for teaching and learning are needed that elevate all students' capacities--not just the select few who excel in narrow subsets of…

Hay/Modern Healthcare compensation survey.

PubMed

Berg, E

1991-06-10

Healthcare chief executives' base salaries overtook those of their industrial counterparts, but they still lagged when comparing total pay, according to this year's Hay/Modern Healthcare Compensation Survey. Even in total compensation, however, healthcare execs were narrowing the gap. The survey also found disparities in pay levels reflected regional factors such as the competitive environment and high cost of living.

Bridging the Gender Gap: The demographics of scientists in the USDA Forest Service and academia

Treesearch

Christel C. Kern; Laura S. Kenefic; Susan L. Stout

2015-01-01

Past research has established that diverse scientific communities foster innovation and problem solving more effectively than communities with a narrow range of knowledge, skills, and experience. However, gender diversity among scientists is limited, particularly in natural-resource fields. We compared data on scientist gender and rank from the US Department of...

ALA Salary Survey: Personal Members

ERIC Educational Resources Information Center

American Libraries, 1971

1971-01-01

A survey of the members of the American Library Association revealed that the principal salary determinants are academic degree, type of employer and sex. The obvious differences in the earnings of men and women is not only found in the early experience years but any narrowing which does take place in the wage gap seems to take place at the…

U.S. School Reform Policy, State Accountability Systems and the Limited English Proficient Student.

ERIC Educational Resources Information Center

Reyes, Pedro; Rorrer, Andrea

2001-01-01

Addresses the political and policy environment that has shaped the educational agenda for rising U.S. state accountability systems, highlighting these policies' effects on the limited-English-proficient learner. The hope for language-minority students lies in pressures on school officials to narrow the white/minority achievement gap. (Contains 64…

Developing MOOCs to Narrow the College Readiness Gap: Challenges and Recommendations for a Writing Course

ERIC Educational Resources Information Center

Bandi-Rao, Shoba; Devers, Christopher J.

2015-01-01

Massive Open Online Courses (MOOCs) have demonstrated the potential to deliver quality and cost effective course materials to large numbers of students. Approximately 60% of first-year students at community colleges are underprepared for college-level coursework. One reason for low graduation rates is the lack of the overall college readiness.…

Effects of the High School Economics Curriculum on Learning in the College Principles Class.

ERIC Educational Resources Information Center

Lopus, Jane S.

1997-01-01

Asserts that most research into the effects of high school economics curriculum upon performance in college level economics courses fails to consider that secondary economics education rarely teaches micro- and macroeconomic concepts. Discovers that any gap in learning between students in economics is narrowed by the first semester in college.…

An Analysis of Gender Equity in the Federal Labor Relations Career Field.

ERIC Educational Resources Information Center

Baker, Bud; Wendt, Ann; Slonaker, William

2002-01-01

Government employment statistics indicate that the number of federal labor relations specialists declined 7% from 1991-2000; the proportion of women in the field grew from 42.2% to 50.9%; and the pay gap narrowed. The number of women in upper management rose 18% between 1991 and 1998. (Contains 31 references.) (SK)

Surfactant 1-Hexadecyl-3-methylimidazolium Chloride Can Convert One-Dimensional Viologen Bromoplumbate into Zero-Dimensional.

PubMed

Liu, Guangfeng; Liu, Jie; Nie, Lina; Ban, Rui; Armatas, Gerasimos S; Tao, Xutang; Zhang, Qichun

2017-05-15

A zero-dimensional N,N'-dibutyl-4,4'-dipyridinium bromoplumbate, [BV] 6 [Pb 9 Br 30 ], with unusual discrete [Pb 9 Br 30 ] 12- anionic clusters was prepared via a facile surfactant-mediated solvothermal process. This bromoplumbate exhibits a narrower optical band gap relative to the congeneric one-dimensional viologen bromoplumbates.

Women and Men Go to University: Mathematical Background and Gender Differences in Choice of Field in Higher Education.

ERIC Educational Resources Information Center

Ayalon, Hanna

2003-01-01

Using data on applicants to an Israeli university, researchers examined whether high school course-taking patterns affected gender segregation in higher education. Women were underrepresented among applicants to mathematics-related studies. Mathematical background in high school effectively narrowed the gender gap in applying to selective and…

Improving Student Outcomes: Restoring America's Education Potential. Strategy Paper

ERIC Educational Resources Information Center

Greenstone, Michael; Looney, Adam; Shevlin, Paige

2011-01-01

For decades, investments in public education have boosted U.S. productivity and earnings, forged a path out of poverty for many families, helped disadvantaged students narrow the learning gap with their peers, and developed a workforce that continues to be among the most productive and innovative on Earth. More recently, this engine of growth has…

Extending In Vitro Conditioning in "Aplysia" to Analyze Operant and Classical Processes in the Same Preparation

ERIC Educational Resources Information Center

Brembs, Bjorn; Baxter, Douglas A.; Byrne, John H.

2004-01-01

Operant and classical conditioning are major processes shaping behavioral responses in all animals. Although the understanding of the mechanisms of classical conditioning has expanded significantly, the understanding of the mechanisms of operant conditioning is more limited. Recent developments in "Aplysia" are helping to narrow the gap in the…

Will Obama's "My Brother's Keeper" and Similar Initiatives Have a Positive Impact on Low-Income Students?

ERIC Educational Resources Information Center

Sanacore, Joseph

2017-01-01

Barack Obama's "My Brother's Keeper" is designed to narrow persistent gaps that boys and young men of color confront often and to help all young people achieve their potential in college and career. An important part of this initiative is comprehensive mentoring that supports students in schools and in communities. Because…

The Effects of GO Centers on Creating a College Culture in Urban High Schools in Texas

ERIC Educational Resources Information Center

Stillisano, Jacqueline R.; Brown, Danielle B.; Alford, Beverly L.; Waxman, Hersh C.

2013-01-01

Despite a generation of efforts to make higher education an achievable goal for all students, the gap in college participation rates between low-income and high-income students has not narrowed. Moreover, students of color continue to be underrepresented on postsecondary campuses. Early intervention efforts and college outreach programs such as…

The Market Work Behavior and Wages of Women 1975-94.

ERIC Educational Resources Information Center

Pencavel, John

1998-01-01

A study examined schooling, weekly and annual working hours, and hourly earnings of women organized into nine birth cohorts, 1920 to 1964. Many more women are working now than did 20 years ago. The gap between the work of married and unmarried women has narrowed. Schooling and wage differences have widened in recent cohorts. (SK)

The Mediating Effect of ICT Usage on the Relationship between Students' Socioeconomic Status and Achievement

ERIC Educational Resources Information Center

Chiao, Chi; Chiu, Chiung-Hui

2018-01-01

To find out if information and communication technology (ICT) could narrow the achievement gaps among students caused by variations in their socioeconomic status, this study examines the mediating mechanism of ICT use between students' socioeconomic status (SES) and achievement. Data from the 2012 East Asia Program for International Student…

Factors that Influence STEM-Promising Females' Decision to Attend a Non Research-Intensive Undergraduate Institution

ERIC Educational Resources Information Center

Miller, Roxanne Greitz; Hurlock, Ashley J.

2017-01-01

Non research-intensive institutions of higher education are effective at narrowing STEM gender gaps in major selection and persistence to degree completion, yet the decision to attend such a setting is likely seen as counterintuitive when such institutions typically have lower levels of research, financial resources, and total student enrollments…

The Supply and Demand of High-Achieving Hispanic Students

ERIC Educational Resources Information Center

Gurantz, Oded; Hurwitz, Michael; Smith, Jonathan

2016-01-01

Hispanics are the largest minority group in the United States, increasing almost six-fold from 1970 to 2014. Although Hispanics youth in the U.S. have traditionally had lower college attendance rates, some sources suggest a narrowing of the White-Hispanic postsecondary attendance gap over the last fifteen years. A key question is whether altering…

Adolescent Girls' Experiences and Gender-Related Beliefs in Relation to Their Motivation in Math/Science and English

ERIC Educational Resources Information Center

Leaper, Campbell; Farkas, Timea; Brown, Christia Spears

2012-01-01

Although the gender gap has dramatically narrowed in recent decades, women remain underrepresented in many science, technology, engineering, and mathematics (STEM) fields. This study examined social and personal factors in relation to adolescent girls' motivation in STEM (math/science) versus non-STEM (English) subjects. An ethnically diverse…

A Critical Praxis: Narrowing the Gap between Identity, Theory, and Practice

ERIC Educational Resources Information Center

Waller, Laurel; Wethers, Kinsey; De Costa, Peter I.

2017-01-01

Praxis is the balance of pedagogical theory and practice. This literature review explores praxis from a critical lens in terms of identity for both students and teachers. The authors center their framework on Hawkins and Norton's (2009) five principles for critical language teaching. The first principle relates to the situated nature of the…

Can Instructional Reform in Urban Middle Schools Help Students Narrow the Mathematics Performance Gap? Some Evidence from the QUASAR Project.

ERIC Educational Resources Information Center

Silver, Edward A.; Lane, Suzanne

1995-01-01

Compared mathematical performance of middle school students in low-income communities involved in the QUASAR project to those of a demographically similar school and of a nationally representative sample. QUASAR mathematics instruction emphasizes reasoning, problem-solving, and understanding. Quasar students outperformed NAEP's disadvantaged urban…

Narrowing the Distance: Bridging the Gap between Teaching Online and Faculty Development

ERIC Educational Resources Information Center

Rochefort, Beth A.

2013-01-01

Online education is a steadily growing industry, and financial pressure at institutions, combined with the rising demand for online education, have caused many universities and colleges to rely on adjunct faculty to staff their online courses For instructors, the transition to teaching online can pose a variety of barriers not the least of which…

Narrowing the Gap: Effects of Intervention on Developmental Trajectories in Autism

ERIC Educational Resources Information Center

Klintwall, Lars; Eldevik, Sigmund; Eikeseth, Svein

2015-01-01

Although still a matter of some debate, there is a growing body of research supporting Early and Intensive Behavioral Intervention as the intervention of choice for children with autism. Learning rate is an alternative to change in standard scores as an outcome measure in studies of early intervention. Learning rates can be displayed graphically…

Academic Achievement Academy (AAA), 2011-12. Eye on Evaluation. D&A Report No. 13.03

ERIC Educational Resources Information Center

Rhea, Anisa

2013-01-01

Extending the school day through programs that will supplement core courses, such as offering intensive, after-school tutoring or small-group study sessions in reading and mathematics, is one method districts use to boost school performance and narrow educational achievement gaps between students of different racial and economic backgrounds (Redd…

Narrowing the Academic Achievement Gap among High School Latino Students through Parental Involvement

ERIC Educational Resources Information Center

Parry, Douglas L.

2010-01-01

The low academic achievement among Latino students in many inner city high schools leads to higher failure, dropout, and absenteeism rates, as well as lower standardized test scores and graduation rates. The purpose of this study was to explore whether Latino parental attitudes toward and perceptions, level of, and form of involvement may be…

Learning By Serving: 2,000 Ideas for Service-Learning Projects. Hot Topics: Usable Research.

ERIC Educational Resources Information Center

Follman, Joseph; And Others

Defining service learning as the formal integration of public service into student instruction and learning, this guide provides teachers with ideas for narrowing the gap between what students do in school and what they will do after they leave school. The example activities, derived from actual projects, demonstrate the nearly limitless range of…

Practitioners and Practices in Museum Education: The Case of Three Jewish Museums

ERIC Educational Resources Information Center

Moghadam, Yaara Shteinhart

2011-01-01

As Jewish museums are witnessing a rapid numerical rise in the United States and beyond, the professional and academic literature on Jewish museum education lags behind. This dissertation is aimed to help narrow this gap by examining how the education departments of Jewish museums in the United States conceptualize, promote, and conduct programs…

Narrowing the Gap between Readers and Books

ERIC Educational Resources Information Center

Hinton, KaaVonia; Dickinson, Gail K.

2005-01-01

So much hinges on putting the right book in a student's hands. Motivation to read is the foundation from which knowledge, reading competency, and comprehension grow. But how do we do it? Here, Hinton and Dickinson offer practical advice for how to reach kids through a partnership with library media specialists and a commitment to promoting books…

Using EIKEN, TOEFL, and TOEIC to Award EFL Course Credits in Japanese Universities

ERIC Educational Resources Information Center

In'nami, Yo; Koizumi, Rie

2017-01-01

Despite the wide use of language tests as a basis for awarding English language course credits at Japanese universities, little has been published about how universities set policies on awarding credits according to external test scores. To narrow this gap, the characteristics of such policies were investigated in relation to the EIKEN Test in…

Digital Storytelling to Engage Postgraduates in Reflective Practice in an Emerging Economy

ERIC Educational Resources Information Center

Dreyer, Lorna M.

2017-01-01

Many emerging economies are just beginning to consume digital content meaningfully. In the field of education in particular, such technology could help to narrow the gap between teacher training and the expectations of a post-colonial, post-apartheid education system in an emerging economy. However, it is important that the use of technology in…

Achieving a sustainable service advantage.

PubMed

Coyne, K P

1993-01-01

Many managers believe that superior service should play little or no role in competitive strategy; they maintain that service innovations are inherently copiable. However, the author states that this view is too narrow. For a company to achieve a lasting service advantage, it must base a new service on a capability gap that competitors cannot or will not copy.

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

Babadi, A. S., E-mail: aein.shiri-babadi@eit.lth.se; Lind, E.; Wernersson, L. E.

A qualitative analysis on capacitance-voltage and conductance data for high-κ/InAs capacitors is presented. Our measured data were evaluated with a full equivalent circuit model, including both majority and minority carriers, as well as interface and border traps, formulated for narrow band gap metal-oxide-semiconductor capacitors. By careful determination of interface trap densities, distribution of border traps across the oxide thickness, and taking into account the bulk semiconductor response, it is shown that the trap response has a strong effect on the measured capacitances. Due to the narrow bandgap of InAs, there can be a large surface concentration of electrons and holesmore » even in depletion, so a full charge treatment is necessary.« less

Innovative discharge geometries for diffusion-cooled gas lasers

NASA Astrophysics Data System (ADS)

Lapucci, Antonio

2004-09-01

Large area, narrow discharge gap, diffusion cooled gas lasers are nowadays a well established technology for the construction of industrial laser sources. Successful examples exist both with the slab (Rofin-Sinar) or coaxial (Trumpf) geometry. The main physical properties and the associated technical problems of the transverse large area RF discharge, adopted for the excitation of high power diffusion cooled gas lasers, are reviewed here. The main problems of this technology are related to the maintenance of a uniform and stable plasma excitation between closely spaced large-area electrodes at high power-density loading. Some practical solutions such as distributed resonance of the discharge channel proved successful in the case of square or rectangular cross-sections but hardly applicable to geometries such as that of coaxial electrodes. In this paper we present some solutions, adopted by our group, for the development of slab and annular CO2 lasers and for CO2 laser arrays with linear or circular symmetry. We will also briefly mention the difficulties encountered in the extraction of a good quality beam from an active medium with such a cross section. A problem that has also seen some interesting solutions.

The Ontario printed educational message (OPEM) trial to narrow the evidence-practice gap with respect to prescribing practices of general and family physicians: a cluster randomized controlled trial, targeting the care of individuals with diabetes and hypertension in Ontario, Canada

PubMed Central

Zwarenstein, Merrick; Hux, Janet E; Kelsall, Diane; Paterson, Michael; Grimshaw, Jeremy; Davis, Dave; Laupacis, Andreas; Evans, Michael; Austin, Peter C; Slaughter, Pamela M; Shiller, Susan K; Croxford, Ruth; Tu, Karen

2007-01-01

Background There are gaps between what family practitioners do in clinical practice and the evidence-based ideal. The most commonly used strategy to narrow these gaps is the printed educational message (PEM); however, the attributes of successful printed educational messages and their overall effectiveness in changing physician practice are not clear. The current endeavor aims to determine whether such messages change prescribing quality in primary care practice, and whether these effects differ with the format of the message. Methods/design The design is a large, simple, factorial, unblinded cluster-randomized controlled trial. PEMs will be distributed with informed, a quarterly evidence-based synopsis of current clinical information produced by the Institute for Clinical Evaluative Sciences, Toronto, Canada, and will be sent to all eligible general and family practitioners in Ontario. There will be three replicates of the trial, with three different educational messages, each aimed at narrowing a specific evidence-practice gap as follows: 1) angiotensin-converting enzyme inhibitors, hypertension treatment, and cholesterol lowering agents for diabetes; 2) retinal screening for diabetes; and 3) diuretics for hypertension. For each of the three replicates there will be three intervention groups. The first group will receive informed with an attached postcard-sized, short, directive "outsert." The second intervention group will receive informed with a two-page explanatory "insert" on the same topic. The third intervention group will receive informed, with both the above-mentioned outsert and insert. The control group will receive informed only, without either an outsert or insert. Routinely collected physician billing, prescription, and hospital data found in Ontario's administrative databases will be used to monitor pre-defined prescribing changes relevant and specific to each replicate, following delivery of the educational messages. Multi-level modeling will be used to study patterns in physician-prescribing quality over four quarters, before and after each of the three interventions. Subgroup analyses will be performed to assess the association between the characteristics of the physician's place of practice and target behaviours. A further analysis of the immediate and delayed impacts of the PEMs will be performed using time-series analysis and interventional, auto-regressive, integrated moving average modeling. Trial registration number Current controlled trial ISRCTN72772651. PMID:18039361

Syntheses, structures and photoelectrochemical properties of three water-stable, visible light absorbing mental-organic frameworks based on tetrakis(4-carboxyphenyl)silane and 1,4-bis(pyridyl)benzene mixed ligands

NASA Astrophysics Data System (ADS)

Guo, Tiantian; Yang, Xiaowei; Li, Ruyan; Liu, Xiaoyu; Gao, Yanling; Dai, Zhihui; Fang, Min; Liu, Hong-Ke; Wu, Yong

2017-09-01

Photovoltaics (PV), which directly convert solar energy into electricity generally using semiconductors, offer a practical and sustainable solution to the current energy shortage and environmental pollution crisis. Photovoltaic applications of metal-organic frameworks (MOFs) belong to a relatively new area of research. Given that UV light accounts for only 4% while visible light contributes 43% of solar energy, it is rather imperative to develop semiconductors with narrow band gaps so that they could absorb visible light. In this work, three water-stable, narrow band semiconducting MOFs of [Cu(H2TCS)(H2O)] (1), [Co(H2TCS)(BPB)] (2) and [Ni(H2TCS)(BPB)] (3) were synthesized using tetrakis(4-carboxyphenyl)silane (H4TCS) and 1,4-bis (pyridyl)benzene (BPB) in water, and structurally characterized by single-crystal X-ray diffractions. MOF 1 has a 2D structure. MOF 2 and 3 are isostructrual and have 3D frameworks formed by interwoven 2D layers. All three MOFs are stable in acidic water solutions and can be stable in water for 7 days. MOFs 1-3 absorb UV and visible light and have band gaps of 0.50, 1.77 and 1.49 eV, respectively. Rapid and stable photocurrent responses of MOFs 1-3 under UV and visible light illuminations are observed. This work demonstrates that using electron rich Cu2+, Co2+, or Ni2+ as metal nodes can effectively decrease the band gaps of MOFs to make them absorbing visible light. To increase the conjugation in the linker is generally considered to be the method to decrease the band gap of MOFs. The conjugation in H4TCS is not significant and this ligand basically only absorbs UV light. However, by using electron rich Cu2+ ions as metal nodes, the prepared [Cu(H2TCS)(H2O)]·H2O (1) absorbs broadly in the visible light region. Thus, this work suggests that by using electron rich Cu2+, many narrow-band semiconductor MOFs can be prepared even by using ligands which only absorbs UV light.

34 CFR 692.94 - What requirements must a State satisfy, as the administrator of a partnership, to receive GAP...

Code of Federal Regulations, 2010 CFR

2010-07-01

... GAP Program funds? To receive GAP Program funds for any fiscal year— (a) A State must— (1) Participate... administrator of a partnership, to receive GAP Program funds? 692.94 Section 692.94 Education Regulations of the... section. (Authority: 20 U.S.C. 1070c-3a) How Does a State Apply to Participate in GAP? ...

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

Gibbs, Zachary M.; Kim, Hyun-Sik; Materials Research Center, Samsung Advanced Institute of Technology, Samsung Electronics, Suwon 443-803

In characterizing thermoelectric materials, electrical and thermal transport measurements are often used to estimate electronic band structure properties such as the effective mass and band gap. The Goldsmid-Sharp band gap, E{sub g} = 2e|S|{sub max}T{sub max}, is a tool widely employed to estimate the band gap from temperature dependent Seebeck coefficient measurements. However, significant deviations of more than a factor of two are now known to occur. We find that this is when either the majority-to-minority weighted mobility ratio (A) becomes very different from 1.0 or as the band gap (E{sub g}) becomes significantly smaller than 10 k{sub B}T. For narrow gapsmore » (E{sub g} ≲ 6 k{sub B}T), the Maxwell-Boltzmann statistics applied by Goldsmid-Sharp break down and Fermi-Dirac statistics are required. We generate a chart that can be used to quickly estimate the expected correction to the Goldsmid-Sharp band gap depending on A and S{sub max}; however, additional errors can occur for S < 150 μV/K due to degenerate behavior.« less

Anomalous Temperature Dependence of the Band Gap in Black Phosphorus.

PubMed

Villegas, Cesar E P; Rocha, A R; Marini, Andrea

2016-08-10

Black phosphorus (BP) has gained renewed attention due to its singular anisotropic electronic and optical properties that might be exploited for a wide range of technological applications. In this respect, the thermal properties are particularly important both to predict its room temperature operation and to determine its thermoelectric potential. From this point of view, one of the most spectacular and poorly understood phenomena is indeed the BP temperature-induced band gap opening; when temperature is increased, the fundamental band gap increases instead of decreases. This anomalous thermal dependence has also been observed recently in its monolayer counterpart. In this work, based on ab initio calculations, we present an explanation for this long known and yet not fully explained effect. We show that it arises from a combination of harmonic and lattice thermal expansion contributions, which are in fact highly interwined. We clearly narrow down the mechanisms that cause this gap opening by identifying the peculiar atomic vibrations that drive the anomaly. The final picture we give explains both the BP anomalous band gap opening and the frequency increase with increasing volume (tension effect).

Band gap bowing in NixMg1−xO

PubMed Central

Niedermeier, Christian A.; Råsander, Mikael; Rhode, Sneha; Kachkanov, Vyacheslav; Zou, Bin; Alford, Neil; Moram, Michelle A.

2016-01-01

Epitaxial transparent oxide NixMg1−xO (0 ≤ x ≤ 1) thin films were grown on MgO(100) substrates by pulsed laser deposition. High-resolution synchrotron X-ray diffraction and high-resolution transmission electron microscopy analysis indicate that the thin films are compositionally and structurally homogeneous, forming a completely miscible solid solution. Nevertheless, the composition dependence of the NixMg1−xO optical band gap shows a strong non-parabolic bowing with a discontinuity at dilute NiO concentrations of x < 0.037. Density functional calculations of the NixMg1−xO band structure and the density of states demonstrate that deep Ni 3d levels are introduced into the MgO band gap, which significantly reduce the fundamental gap as confirmed by optical absorption spectra. These states broaden into a Ni 3d-derived conduction band for x > 0.074 and account for the anomalously large band gap narrowing in the NixMg1−xO solid solution system. PMID:27503808

The wave attenuation mechanism of the periodic local resonant metamaterial

NASA Astrophysics Data System (ADS)

Chang, I.-Ling; Liang, Zhen-Xian; Kao, Hao-Wei; Chang, Shih-Hsiang; Yang, Chih-Ying

2018-01-01

This research discusses the wave propagation behavior and attenuation mechanism of the elastic metamaterial with locally resonant sub-structure. The dispersion relation of the single resonance system, i.e., periodic spring mass system with sub-structure, could be derived based on lattice dynamics and the band gap could be easily identified. The dynamically equivalent properties, i.e., mass and elastic property, of the single resonance system are derived and found to be frequency dependent. Negative effective properties are found in the vicinity of the local resonance. It is examined whether the band gap always coincides with the frequency range of negative effective properties. The wave attenuation mechanism and the characteristic dynamic behavior of the elastic metamaterial are also studied from the energy point of view. From the analysis, it is clarified that the coupled Bragg-resonance band gap is much wider than the narrow-banded local resonance and the corresponding effective material properties at band gap could be either positive or negative. However, the band gap is totally overlapping with the frequency range of negative effective properties for the metamaterial with band gap purely caused by local resonance. The presented analysis can be extended to other forms of elastic metamaterials involving periodic resonator structures.

Microengineering of Metals and Ceramics: Part I: Design, Tooling and Injection Molding; Volume 3: Advanced Micro & Nanosystems

NASA Astrophysics Data System (ADS)

Baltes, Henry; Brand, Oliver; Fedder, Gary K.; Hierold, Christofer; Korvink, Jan G.; Tabata, Osamu; Löhe, Detlef; Haußelt, Jürgen

2005-09-01

Microstructures, electronics, nanotechnology - these vast fields of research are growing together as the size gap narrows and many different materials are combined. Current research, engineering sucesses and newly commercialized products hint at the immense innovative potentials and future applications that open up once mankind controls shape and function from the atomic level right up to the visible world without any gaps. In this volume, authors from three major competence centres for microengineering illustrate step by step the process from designing and simulating microcomponents of metallic and ceramic materials to replicating micro-scale components by injection molding.

Thermoelectric properties of layered NaSbSe2.

PubMed

Putatunda, Aditya; Xing, Guangzong; Sun, Jifeng; Li, Yuwei; Singh, David J

2018-06-06

We investigate ordered monoclinic NaSbSe 2 as a thermoelectric using first principles calculations. We find that from an electronic point of view, ordered and oriented n-type NaSbSe 2 is comparable to the best known thermoelectric materials. This phase has a sufficiently large band gap for thermoelectric and solar absorber applications in contrast to the disordered phase which has a much narrower gap. The electronic structure shows anisotropic, non-parabolic bands. The results show a high Seebeck coefficient in addition to direction dependent high conductivity. The electronic structure quantified by an electron fitness function is very favorable, especially in the n-type case.

Thermoelectric properties of layered NaSbSe2

NASA Astrophysics Data System (ADS)

Putatunda, Aditya; Xing, Guangzong; Sun, Jifeng; Li, Yuwei; Singh, David J.

2018-06-01

We investigate ordered monoclinic NaSbSe2 as a thermoelectric using first principles calculations. We find that from an electronic point of view, ordered and oriented n-type NaSbSe2 is comparable to the best known thermoelectric materials. This phase has a sufficiently large band gap for thermoelectric and solar absorber applications in contrast to the disordered phase which has a much narrower gap. The electronic structure shows anisotropic, non-parabolic bands. The results show a high Seebeck coefficient in addition to direction dependent high conductivity. The electronic structure quantified by an electron fitness function is very favorable, especially in the n-type case.

Computer-assisted virtual autopsy using surgical navigation techniques.

PubMed

Ebert, Lars Christian; Ruder, Thomas D; Martinez, Rosa Maria; Flach, Patricia M; Schweitzer, Wolf; Thali, Michael J; Ampanozi, Garyfalia

2015-01-01

OBJECTIVE; Virtual autopsy methods, such as postmortem CT and MRI, are increasingly being used in forensic medicine. Forensic investigators with little to no training in diagnostic radiology and medical laypeople such as state's attorneys often find it difficult to understand the anatomic orientation of axial postmortem CT images. We present a computer-assisted system that permits postmortem CT datasets to be quickly and intuitively resliced in real time at the body to narrow the gap between radiologic imaging and autopsy. Our system is a potentially valuable tool for planning autopsies, showing findings to medical laypeople, and teaching CT anatomy, thus further closing the gap between radiology and forensic pathology.

Electrochemical deposition of copper decorated titania nanotubes and its visible light photocatalytic performance

NASA Astrophysics Data System (ADS)

Lim, Y. C.; Siti, A. S.; Nur Amiera, P.; Devagi, K.; Lim, Y. P.

2017-09-01

Coupling of titania with narrow band gap materials has been a promising strategy in preparing visible light responsive photocatalyst. In this work, self-organized copper decorated TiO2 nanotube (Cu/TNT) was prepared via electrodeposition of Cu onto highly ordered titania nanotube arrays (TNT). The catalysts were characterized by X-ray diffraction, diffuse reflectance spectroscopy (DRS), field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX). The DRS studies clearly show the extended absorption of Cu/TNT into the visible region and present a red shift of band gap to 2.1 eV. FESEM analysis has shown the dispersion of cubic-like Cu particles upon electrodeposition and EDX analysis supports the presence of copper species on the nanotubes surface. The photocatalytic ability of Cu/TNT was evaluated by the degradation of methyl orange from aqueous solution under low power visible light illumination. Compared to TNT, an appreciable improvement in methyl orange removal was observed for Cu/TNT and the highest removal efficiency of 80% was achieved. The effects of catalyst loading and samples repeatability were investigated and under optimum conditions, the removal efficiency of methyl orange over Cu/TNT had further increased to 93.4%. This work has demonstrated a feasible and simple way to introduce narrow band gap transition metal into nanotube arrays, which could create novel properties for functionalized nanotube arrays as well as promise a wide range of applications.

Fusing Benzo[c][1,2,5]oxadiazole Unit with Thiophene for Constructing Wide-bandgap High-performance IDT-based Polymer Solar Cell Donor Material.

PubMed

Song, Xin; Fan, Meijie; Zhang, Kaili; Ding, Dakang; Chen, Weiye; Li, Yonghai; Yu, Liangmin; Sun, Mingliang; Yang, Renqiang

2018-04-01

Benzo[c][1,2,5]oxadiazole (BO) moiety is a strong electron-withdrawing unit compared to benzo[c][1,2,5]thiadiazole (BT). It is usually introduced as an acceptor to construct narrow band-gap donor-acceptor (D-A) materials. Herein, the π-extended conjugated moiety dithieno[3',2':3,4″;2,3″:5,6]benzo[1,2-c][1,2,5]oxadiazole (BOT) was adopted as the acceptor moiety to design D-A polymers. Considering the more extended π-conjugated molecular system of BOT compared to the BO unit, a narrower optical band-gap is expected for BOT-based IDT polymer (PIDT-BOT). Unexpectedly, the UV-vis absorption spectra of PIDT-BOT films display a great hypochromatic shift of about 60 nm compared to a BO-based analog (PIDT-BO). The optical band-gaps of the materials are broadened from 1.63 eV (PIDT-BO) to 2.00 eV (PIDT-BOT) accordingly. Although the range of external quantum efficiency (EQE) of PIDT-BOT-based polymer solar cell (PSC) devices is not as wide as for PIDT-BO-based devices, the EQE response intensities of the PIDT-BOT based device are evidently high. As a result, PSC devices based on PIDT-BOT reveal the best power conversion efficiency at 6.08%. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Saturn's Misbegotten Moonlets

NASA Astrophysics Data System (ADS)

Spitale, Joseph N.

2017-06-01

Saturn's rings are interspersed with numerous narrow (tens of km wide) gaps. Two of the largest of these gaps -- Encke and Keeler -- contain satellites -- Pan and Daphnis -- that maintain their respective gaps via the classical Goldreich/Tremaine-style shepherding mechanism wherein angular momentum is transferred across the essentially empty gap via torques acting between the satellites and the ring. Other prominent gaps are shepherded by resonances with external satellites or planetary modes: Mimas shepherds the outer edge of the B ring, clearing the inner part of the Cassini Division, Titan shepherds the Columbo ringlet / gap, and the Maxwell ringlet / gap is likely maintained by a resonance with a planetary mode. Prior to Cassini, it was expected that all of the gaps would be shepherded in a similar manner.However, many small gaps do not correspond with known resonances, and no satellites were spotted within those gaps during Cassini's prime and extended mission. To address this issue, a series of Cassini imaging observations were planned to examine 11 gaps in the C ring and Cassini division at a resolution and longitudinal coverage sufficient to either discover the shepherds or rule out their presence. The survey discovered no embedded satellites. Longitudinal coverage was incomplete, but within longitudes covered by the survey, satellites are ruled out to sizes in the 100-m range, far too small keep the observed gaps open. It is possible (about even odds) that there could be a larger satellite residing at a longitude not covered in the survey, but the probability that the survey was unfortunate enough to miss significant satellites in all 11 gaps is exceedingly small (~0.002%). Moreover, these gaps appear in earlier imaging sequences, with some high-resolution coverage, so the true probability is smaller yet. Therefore, a new theory is likely needed to explain the presence of the gaps.

34 CFR 692.94 - What requirements must a State satisfy, as the administrator of a partnership, to receive GAP...

Code of Federal Regulations, 2011 CFR

2011-07-01

... partnership, to receive GAP Program funds? To receive GAP Program funds for any fiscal year— (a) A State must... administrator of a partnership, to receive GAP Program funds? 692.94 Section 692.94 Education Regulations of the...)(2)(ii) of this section. (Authority: 20 U.S.C. 1070c-3a) How Does a State Apply to Participate in GAP? ...

High efficient OLED displays prepared with the air-gapped bridges on quantum dot patterns for optical recycling

PubMed Central

Kim, Hyo-Jun; Shin, Min-Ho; Kim, Joo-Suc; Kim, Se-Eun; Kim, Young-Joo

2017-01-01

An optically efficient structure was proposed and fabricated to realize high brightness organic light emitting diode (OLED) displays based on a white OLED prepared with the air-gapped bridges on the quantum dot (QD) patterns. Compared with a conventional white OLED display, in our experiments, the optical intensity of the proposed OLED display shows the enhancement of 58.2% in the red color and 16.8% in the green color after applying the air-gapped bridge structure on QD patterns of 20 wt% concentration. This enhancement comes from the two facts that the QD patterns downconvert unnecessary blue or blue/green light to the required green or red light and the air-gapped bridges increase the color conversion efficiency of QDs by optical recycling using total internal reflection (TIR) at the interface. In addition, the color gamut of the proposed OLED display increases from 65.5 to 75.9% (NTSC x, y ratio) due to the narrow emission spectra of QDs. PMID:28211516

High efficient OLED displays prepared with the air-gapped bridges on quantum dot patterns for optical recycling

NASA Astrophysics Data System (ADS)

Kim, Hyo-Jun; Shin, Min-Ho; Kim, Joo-Suc; Kim, Se-Eun; Kim, Young-Joo

2017-02-01

An optically efficient structure was proposed and fabricated to realize high brightness organic light emitting diode (OLED) displays based on a white OLED prepared with the air-gapped bridges on the quantum dot (QD) patterns. Compared with a conventional white OLED display, in our experiments, the optical intensity of the proposed OLED display shows the enhancement of 58.2% in the red color and 16.8% in the green color after applying the air-gapped bridge structure on QD patterns of 20 wt% concentration. This enhancement comes from the two facts that the QD patterns downconvert unnecessary blue or blue/green light to the required green or red light and the air-gapped bridges increase the color conversion efficiency of QDs by optical recycling using total internal reflection (TIR) at the interface. In addition, the color gamut of the proposed OLED display increases from 65.5 to 75.9% (NTSC x, y ratio) due to the narrow emission spectra of QDs.

High efficient OLED displays prepared with the air-gapped bridges on quantum dot patterns for optical recycling.

PubMed

Kim, Hyo-Jun; Shin, Min-Ho; Kim, Joo-Suc; Kim, Se-Eun; Kim, Young-Joo

2017-02-17

An optically efficient structure was proposed and fabricated to realize high brightness organic light emitting diode (OLED) displays based on a white OLED prepared with the air-gapped bridges on the quantum dot (QD) patterns. Compared with a conventional white OLED display, in our experiments, the optical intensity of the proposed OLED display shows the enhancement of 58.2% in the red color and 16.8% in the green color after applying the air-gapped bridge structure on QD patterns of 20 wt% concentration. This enhancement comes from the two facts that the QD patterns downconvert unnecessary blue or blue/green light to the required green or red light and the air-gapped bridges increase the color conversion efficiency of QDs by optical recycling using total internal reflection (TIR) at the interface. In addition, the color gamut of the proposed OLED display increases from 65.5 to 75.9% (NTSC x, y ratio) due to the narrow emission spectra of QDs.

Second-harmonic generation at angular incidence in a negative-positive index photonic band-gap structure.

PubMed

D'Aguanno, Giuseppe; Mattiucci, Nadia; Scalora, Michael; Bloemer, Mark J

2006-08-01

In the spectral region where the refractive index of the negative index material is approximately zero, at oblique incidence, the linear transmission of a finite structure composed of alternating layers of negative and positive index materials manifests the formation of a new type of band gap with exceptionally narrow band-edge resonances. In particular, for TM-polarized (transverse magnetic) incident waves, field values that can be achieved at the band edge may be much higher compared to field values achievable in standard photonic band-gap structures. We exploit the unique properties of these band-edge resonances for applications to nonlinear frequency conversion, second-harmonic generation, in particular. The simultaneous availability of high field localization and phase matching conditions may be exploited to achieve second-harmonic conversion efficiencies far better than those achievable in conventional photonic band-gap structures. Moreover, we study the role played by absorption within the negative index material, and find that the process remains efficient even for relatively high values of the absorption coefficient.

Optimization of the performance of a tandem microchannel plate detector as a function of interplate spacing and voltage

NASA Technical Reports Server (NTRS)

Rogers, D.; Malina, R. F.

1982-01-01

The effect of varying the size of the gap voltage and spacing on the performance of a tandem pair of microchannel plates (MCP) is investigated. Results show that increasing the voltage in the gap increases the gain of the pair and also produces a narrower Gaussian pulse-height distribution, although beyond a critical voltage the gain of the channel plate pair is found to plateau. A model is developed which explains the nonlinear gain behavior of individual microchannels and the behavior of the electron cloud emitted from the first MCP as it spreads out between the two MCPs and hits the surface of the second. The model calculates the plateau voltage as a function of the gap size, the gain of each MCP, and the diameter of the channels, and is found to show good agreement with the observed results. It is concluded that interplate gaps of up to several millimeters can be accommodated without a significant degradation in pulse-height distribution.

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

Effect of ripple taper on band-gap overlap in a coaxial Bragg structure operating at terahertz frequency

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

Ding Xueyong; Li Hongfan; Lv Zhensu

Based on the mode-coupling method, numerical analysis is presented to demonstrate the influence of ripple taper on band-gap overlap in a coaxial Bragg structure operating at terahertz frequency. Results show that the interval between the band-gaps of the competing mode and the desired working mode is narrowed by use of positive-taper ripples, but is expanded if negative-taper ripples are employed, and the influence of the negative-taper ripples is obviously more advantageous than the positive-taper ripples; the band-gap overlap of modes can be efficiently separated by use of negative-taper ripples. The residual side-lobes of the frequency response in a coaxial Braggmore » structure with ripple taper also can be effectively suppressed by employing the windowing-function technique. These peculiarities provide potential advantage in constructing a coaxial Bragg cavity with high quality factor for single higher-order-mode operation of a high-power free-electron maser in the terahertz frequency range.« less

Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems

PubMed Central

Lee, Wan-Sun; Kim, Woong-Chul

2015-01-01

PURPOSE To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method. MATERIALS AND METHODS Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (α=.05), respectively. RESULTS The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05). CONCLUSION Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 µm). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced. PMID:25932310

Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems.

PubMed

Park, Jong-Kyoung; Lee, Wan-Sun; Kim, Hae-Young; Kim, Woong-Chul; Kim, Ji-Hwan

2015-04-01

To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method. Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (α=.05), respectively. The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05). Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 µm). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.

Child Poverty Was Lower at End of 1990s.

ERIC Educational Resources Information Center

Rogers, Carolyn C.

2001-01-01

Poverty rates increased in the early 1990s, but between 1994 and 1999 the metro child poverty rate declined 6 percentage points and the nonmetro rate declined 4 percent. In 1999, the poverty rate for nonmetro Black children was about double that of nonmetro White children, but the Black-White gap in poverty narrowed between 1985 and 1999. (TD)

Quality Assurance in Distance Education: The Challenges to Be Addressed

ERIC Educational Resources Information Center

Stella, Antony; Gnanam, A.

2004-01-01

Integration of technology in all forms of education has narrowed down the gap between the on- and off-campus students and has resulted in the use of the more broad-based term "distributed learning". Consequently, distance learning is seen as a subset of distributed learning, focusing on students who may be separated in time and space from their…

Student Choice of College: How Far Do Students Go for an Education?

ERIC Educational Resources Information Center

Mattern, Krista; Wyatt, Jeff N.

2009-01-01

The topic of distance from home is often discussed when students begin narrowing down colleges they want to apply to; however, there is a scarcity of research actually examining student behavior. The purpose of this study is to address this research gap using data based on a national sample of nearly one million students. Distance was computed in…

Where Principals Dare to Dream: Critical Friends Group Narrows the Gap between Vision and Reality

ERIC Educational Resources Information Center

Fahey, Kevin

2012-01-01

Being a principal was the most demanding job the author ever had. He worked hard, mostly in isolation. Like most principals, he struggled to manage the position's political and bureaucratic necessities in order to concentrate on what he thought was the fundamental work of schools: teaching and learning. He struggled to continue to learn and grow…

An Exploratory Factor Analysis of the Sheltered Instruction Observation Protocol as an Evaluation Tool to Measure Teaching Effectiveness

ERIC Educational Resources Information Center

Polat, Nihat; Cepik, Saban

2016-01-01

To narrow the achievement gap between English language learners (ELLs) and their native-speaking peers in K-12 settings in the United States, effective instructional models must be identified. However, identifying valid observation protocols that can measure the effectiveness of specially designed instructional practices is not an easy task. This…

An observation of direct-gap electroluminescence in GaAs structures with Ge quantum wells

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

Aleshkin, V. Ya.; Dikareva, N. V.; Dubinov, A. A., E-mail: sanya@ipm.sci-nnov.ru

2015-02-15

A light-emitting diode structure based on GaAs with eight narrow Ge quantum wells is grown by laser sputtering. An electroluminescence line polarized predominately in the plane parallel to the constituent layers of the structure is revealed. The line corresponds to the direct optical transitions in momentum space in the Ge quantum wells.

The Equitable Classroom: Today's Diverse Student Body Needs Culturally Proficient Teachers

ERIC Educational Resources Information Center

Saphier, Jon

2017-01-01

According to new federal data, poor black and Hispanic children are becoming more and more isolated from their white affluent peers in public schools. The data show that the number of high-poverty schools serving students of color has doubled in recent years. And since the 1990s, progress narrowing the achievement gap has plateaued nationwide and…

Parallel Play: Preschool and K-12 Finance Reform in New Jersey and Texas. Working Paper 07-3

ERIC Educational Resources Information Center

Fuller, Bruce; Wright, Joseph

2007-01-01

Gaps in early learning are starkly apparent among differing children even before they enter kindergarten. So, a rising number of states are trying to narrow initial achievement disparities by expanding access to quality preschool. At the same time, recent findings show that preschool is not a lasting inoculation: its benefits fade if children move…

A Case Study to Explore Rigorous Teaching and Testing Practices to Narrow the Achievement Gap

ERIC Educational Resources Information Center

Isler, Tesha

2012-01-01

The problem examined in this study: Does the majority of teachers use rigorous teaching and testing practices? The purpose of this qualitative exploratory case study was to explore the classroom techniques of six effective teachers who use rigorous teaching and testing practices. The hypothesis for this study is that the examination of the…

Conceptualising Discursive Communities: Developing Community in Contemporary Society

ERIC Educational Resources Information Center

Azzopardi, Andrew

2011-01-01

What happens when people find themselves left out of communities? Who is missing and why does it matter? What can one do to narrow the gap? What is community? How has community been represented in theory? The quality of life of a population is an important concern in so many areas, and a significant part of our standard of living is measured by…

Poverty and Potential: Out-of-School Factors and School Success

ERIC Educational Resources Information Center

Berliner, David C.

2009-01-01

The U.S. has set as a national goal the narrowing of the achievement gap between lower income and middle-class students, and that between racial and ethnic groups. This is a key purpose of the No Child Left Behind act, which relies primarily on assessment to promote changes within schools to accomplish that goal. However, out-of-school factors…

Internationalization and Its Implications for the Quality of Higher Education in Africa

ERIC Educational Resources Information Center

Oyewole, Olusola

2009-01-01

African countries and other least developed countries could use knowledge to narrow the income gap between them and the developed world economies. Higher education (HE) is an important institution that these countries will need to develop and improve in order to meet this challenge. The world of HE is however changing everyday, and one of the…

Education Watch: New Mexico. Key Education Facts and Figures. Achievement, Attainment and Opportunity. From Elementary School through College.

ERIC Educational Resources Information Center

Education Trust, Washington, DC.

This report compares New Mexico's reading and mathematics performance on the most recent administrations of the state assessment with performance on the National Assessment of Educational Progress (NAEP). To indicate how New Mexico is doing in narrowing the academic achievement gap between African American and Latino students and their white,…

Picture That: Supporting Sexuality Educators in Narrowing the Knowledge/Practice Gap

ERIC Educational Resources Information Center

Beyers, Christa

2012-01-01

Teaching about sex and relationships is one of the greatest challenges in not only the combating of HIV and AIDS, but also in preparing the youth for responsible sexual behaviour. Although it seems as if teachers to some extent do feel comfortable with the teaching of sexuality education at school, the question however remains as to whether youth…

Mismatch: For New England Women, Earning Lags Learning

ERIC Educational Resources Information Center

Gittell, Ross; Churilla, Allison; Griffin, Ann McAdam

2005-01-01

Over the past 30 years, there has been significant progress in the educational advancement of women in the United States and New England. Nationally, the percentage of adult women with four-year college degrees increased from 8 percent in 1970 to 24 percent in 2000. Women narrowed the gap with men in college completion, as the female-to-male ratio…

Teacher Practice: A Spotlight on the Use of Feedback and Conferencing in the First Year of Schooling

ERIC Educational Resources Information Center

Nicholas, Maria; Paatsch, Louise

2014-01-01

With the prevalence of statements that refer to a need to "bridge", "narrow" or "close" gaps in achievement it would appear that Government bodies have an appreciation for the fact that students need not be victims of circumstance. In addition to this, research has suggested that certain skills, such as the…

How Family Background Influences Student Achievement: Can Schools Narrow the Gap?

ERIC Educational Resources Information Center

Egalite, Anna J.

2016-01-01

On the weekend before the Fourth of July 1966, the U.S. Office of Education quietly released a 737-page report that summarized one of the most comprehensive studies of American education ever conducted. Encompassing some 3,000 schools, nearly 600,000 students, and thousands of teachers, and produced by a team led by Johns Hopkins University…

The Relationship between Low-Income and Minority Children's Physical Activity and Academic-Related Outcomes: A Review of the Literature

ERIC Educational Resources Information Center

Efrat, Merav

2011-01-01

This article explores an innovative strategy for battling the obesity epidemic. The strategy involves demonstrating to policy makers and education leaders the value of promoting physical activity in school as a way of enhancing academic-related outcomes to narrow the current achievement gap. A literature review was conducted to ascertain the…

Early Talk Boost: A Targeted Intervention for Three Year Old Children with Delayed Language Development

ERIC Educational Resources Information Center

Reeves, Louisa; Hartshorne, Mary; Black, Rachael; Atkinson, Jill; Baxter, Amanda; Pring, Tim

2018-01-01

Pre-school education has been greatly expanded in the United Kingdom in the last two decades and further expansion is planned. Its provision allows parents to take up employment thus increasing family incomes and it is expected to narrow the gap between socially disadvantaged children and their peers. The latter is important as studies have shown…

Moving Maryland Forward: Sharpen the Focus for 2020. The Division of Special Education/Early Intervention Services (DSE/EIS) Strategic Plan

ERIC Educational Resources Information Center

Maryland State Department of Education, 2016

2016-01-01

With this Strategic Plan, the Division of Special Education/ Early Intervention Services recommits to "Moving Maryland Forward"--introduced in 2013. With the shifting in the national, State, and local education landscape, Maryland has revisited the initial Plan to sharpen the steadfast focus to narrow the gaps for children with…

Providing Comprehensive Educational Opportunity to Low Income Students. Part 2: How Much Does It Cost?

ERIC Educational Resources Information Center

Rothstein, Richard; Wilder, Tamara; Allgood, Whitney

2011-01-01

The inability of the United States to narrow the achievement gap stems to a large extent from school reform initiatives that neglect the specific conditions in the lives of low-income students that contribute heavily to inadequate school performance. A new consensus is emerging that a more effective approach would be to prevent the achievement gap…

Reducing the Digital Divide through ICT Adoption: Factors, Barriers, and How ICT in Schools Can Help

ERIC Educational Resources Information Center

Tengtrakul, Pitikorn

2013-01-01

Through econometric analysis of data from multiple surveys, this study explores factors that affect ICT adoption and evaluates the extent to which ICT in schools affect the ICT adoption of surrounding communities, in order to provide a perspective that can help narrow the gap of digital divide. Understanding factors affecting ICT adoption may…

Balancing the One-to-One Equation: Equity and Access in Three Laptop Programs

ERIC Educational Resources Information Center

Warschauer, Mark; Zheng, Binbin; Niiya, Melissa; Cotten, Shelia; Farkas, George

2014-01-01

Seeking to improve teaching and learning and to narrow gaps between students of high and low socioeconomic status, many school districts in the United States are implementing one-to-one laptop programs. In this comparative case study, we examine one-to-one laptop programs in Colorado, California, and Alabama, all of which deployed low-cost netbook…

A Self-Improving School System and Its Potential for Reducing Inequality

ERIC Educational Resources Information Center

Hargreaves, David H.

2014-01-01

After a brief review of some milestones in the story of how schools contribute to inequalities in student achievement, more recent work on how experience of collaboration between schools can help to narrow the gap is shown to underpin the new concept of a self-improving school system. The main focus is then on the principal features of a…

Linear Mathematical Model for Seam Tracking with an Arc Sensor in P-GMAW Processes

PubMed Central

Liu, Wenji; Li, Liangyu; Hong, Ying; Yue, Jianfeng

2017-01-01

Arc sensors have been used in seam tracking and widely studied since the 80s and commercial arc sensing products for T and V shaped grooves have been developed. However, it is difficult to use these arc sensors in narrow gap welding because the arc stability and sensing accuracy are not satisfactory. Pulse gas melting arc welding (P-GMAW) has been successfully applied in narrow gap welding and all position welding processes, so it is worthwhile to research P-GMAW arc sensing technology. In this paper, we derived a linear mathematical P-GMAW model for arc sensing, and the assumptions for the model are verified through experiments and finite element methods. Finally, the linear characteristics of the mathematical model were investigated. In torch height changing experiments, uphill experiments, and groove angle changing experiments the P-GMAW arc signals all satisfied the linear rules. In addition, the faster the welding speed, the higher the arc signal sensitivities; the smaller the groove angle, the greater the arc sensitivities. The arc signal variation rate needs to be modified according to the welding power, groove angles, and weaving or rotate speed. PMID:28335425

Specific features of the spectra and relaxation kinetics of long-wavelength photoconductivity in narrow-gap HgCdTe epitaxial films and heterostructures with quantum wells

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

Rumyantsev, V. V., E-mail: rumyantsev@ipmras.ru; Ikonnikov, A. V.; Antonov, A. V.

2013-11-15

The spectra and relaxation kinetics of interband photoconductivity are investigated in narrow-gap Hg{sub 1-x}Cd{sub x}Te epitaxial films with x = 0.19-0.23 and in structures with HgCdTe-based quantum wells (QWs), having an interband-transition energy in the range of 30-90 meV, grown by molecular-beam epitaxy on GaAs (013) substrates. A long-wavelength sensitivity band caused by impurities or defects is found in the spectra of the structures with quantum wells in addition to the interband photoconductivity. It is shown that the lifetimes of nonequilibrium carriers in the structures with QWs is less than in bulk samples at the same optical-transition energy. From themore » measured carrier lifetimes, the ampere-watt responsivity and the equivalent noise power for a film with x = 0.19 at a wavelength of 19 {mu}m are estimated. When investigating the relaxation kinetics of the photoconductivity at 4.2 K in high excitation regime, it is revealed that radiative recombination is dominant over other mechanisms of nonequilibrium-carrier recombination.« less

Linear Mathematical Model for Seam Tracking with an Arc Sensor in P-GMAW Processes.

PubMed

Liu, Wenji; Li, Liangyu; Hong, Ying; Yue, Jianfeng

2017-03-14

Arc sensors have been used in seam tracking and widely studied since the 80s and commercial arc sensing products for T and V shaped grooves have been developed. However, it is difficult to use these arc sensors in narrow gap welding because the arc stability and sensing accuracy are not satisfactory. Pulse gas melting arc welding (P-GMAW) has been successfully applied in narrow gap welding and all position welding processes, so it is worthwhile to research P-GMAW arc sensing technology. In this paper, we derived a linear mathematical P-GMAW model for arc sensing, and the assumptions for the model are verified through experiments and finite element methods. Finally, the linear characteristics of the mathematical model were investigated. In torch height changing experiments, uphill experiments, and groove angle changing experiments the P-GMAW arc signals all satisfied the linear rules. In addition, the faster the welding speed, the higher the arc signal sensitivities; the smaller the groove angle, the greater the arc sensitivities. The arc signal variation rate needs to be modified according to the welding power, groove angles, and weaving or rotate speed.

Comparison of microstructure and mechanical properties of ultra-narrow gap laser and gas-metal-arc welded S960 high strength steel

NASA Astrophysics Data System (ADS)

Guo, Wei; Li, Lin; Dong, Shiyun; Crowther, Dave; Thompson, Alan

2017-04-01

The microstructural characteristics and mechanical properties, including micro-hardness, tensile properties, three-point bending properties and Charpy impact toughness at different test temperatures of 8 mm thick S960 high strength steel plates were investigated following their joining by multi-pass ultra-narrow gap laser welding (NGLW) and gas metal arc welding (GMAW) techniques. It was found that the microstructure in the fusion zone (FZ) for the ultra-NGLW joint was predominantly martensite mixed with some tempered martensite, while the FZ for the GMAW joint was mainly consisted of ferrite with some martensite. The strength of the ultra-NGLW specimens was comparable to that of the base material (BM), with all welded specimens failed in the BM in the tensile tests. The tensile strength of the GMAW specimens was reduced approximately by 100 MPa when compared with the base material by a broad and soft heat affected zone (HAZ) with failure located in the soft HAZ. Both the ultra-NGLW and GMAW specimens performed well in three-point bending tests. The GMAW joints exhibited better impact toughness than the ultra-NGLW joints.

New high Tc multiferroics KBiFe2O5 with narrow band gap and promising photovoltaic effect

PubMed Central

Zhang, Ganghua; Wu, Hui; Li, Guobao; Huang, Qingzhen; Yang, Chongyin; Huang, Fuqiang; Liao, Fuhui; Lin, Jianhua

2013-01-01

Intrinsic polarization of ferroelectrics (FE) helps separate photon-generated charge carriers thus enhances photovoltaic effects. However, traditional FE with transition-metal cations (M) of d0 electron in MO6 network typically has a band gap (Eg) exceeding 3.0 eV. Although a smaller Eg (2.6 eV) can be obtained in multiferroic BiFeO3, the value is still too high for optimal solar energy applications. Computational “materials genome” searches have predicted several exotic MO6 FE with Eg < 2.0 eV, all thus far unconfirmed because of synthesis difficulties. Here we report a new FE compound with MO4 tetrahedral network, KBiFe2O5, which features narrow Eg (1.6 eV), high Curie temperature (Tc ~ 780 K) and robust magnetic and photoelectric activities. The high photovoltage (8.8 V) and photocurrent density (15 μA/cm2) were obtained, which is comparable to the reported BiFeO3. This finding may open a new avenue to discovering and designing optimal FE compounds for solar energy applications. PMID:23405279

Risk Adjustment May Lessen Penalties On Hospitals Treating Complex Cardiac Patients Under Medicare's Bundled Payments.

PubMed

Markovitz, Adam A; Ellimoottil, Chandy; Sukul, Devraj; Mullangi, Samyukta; Chen, Lena M; Nallamothu, Brahmajee K; Ryan, Andrew M

2017-12-01

To reduce variation in spending, Medicare has considered implementing a cardiac bundled payment program for acute myocardial infarction and coronary artery bypass graft. Because the proposed program does not account for patient risk factors when calculating hospital penalties or rewards ("reconciliation payments"), it might unfairly penalize certain hospitals. We estimated the impact of adjusting for patients' medical complexity and social risk on reconciliation payments for Medicare beneficiaries hospitalized for the two conditions in the period 2011-13. Average spending per episode was $29,394. Accounting for medical complexity substantially narrowed the gap in reconciliation payments between hospitals with high medical severity (from a penalty of $1,809 to one of $820, or a net reduction of $989), safety-net hospitals (from a penalty of $217 to one of $87, a reduction of $130), and minority-serving hospitals (from a penalty of $70 to a reward of $56, an improvement of $126) and their counterparts. Accounting for social risk alone narrowed these gaps but had minimal incremental effects after medical complexity was accounted for. Risk adjustment may preserve incentives to care for patients with complex conditions under Medicare bundled payment programs.

Theory of g-factor enhancement in narrow-gap quantum well heterostructures.

PubMed

Krishtopenko, S S; Gavrilenko, V I; Goiran, M

2011-09-28

We report on the study of the exchange enhancement of the g-factor in the two-dimensional (2D) electron gas in n-type narrow-gap semiconductor heterostructures. Our approach is based on the eight-band k⋅p Hamiltonian and takes into account the band nonparabolicity, the lattice deformation, the spin-orbit coupling and the Landau level broadening in the δ-correlated random potential model. Using the 'screened' Hartree-Fock approximation we demonstrate that the exchange g-factor enhancement not only shows maxima at odd values of Landau level filling factors but, due to the conduction band nonparabolicity, persists at even filling factor values as well. The magnitude of the exchange enhancement, the amplitude and the shape of the g-factor oscillations are determined by both the screening of the electron-electron interaction and the Landau level width. The 'enhanced' g-factor values calculated for the 2D electron gas in InAs/AlSb quantum well heterostructures are compared with our earlier experimental data and with those obtained by Mendez et al (1993 Phys. Rev. B 47 13937) in magnetic fields up to 30 T.

Schottky diode model for non-parabolic dispersion in narrow-gap semiconductor and few-layer graphene

NASA Astrophysics Data System (ADS)

Ang, Yee Sin; Ang, L. K.; Zubair, M.

Despite the fact that the energy dispersions are highly non-parabolic in many Schottky interfaces made up of 2D material, experimental results are often interpreted using the conventional Schottky diode equation which, contradictorily, assumes a parabolic energy dispersion. In this work, the Schottky diode equation is derived for narrow-gap semiconductor and few-layer graphene where the energy dispersions are highly non-parabolic. Based on Kane's non-parabolic band model, we obtained a more general Kane-Schottky scaling relation of J (T2 + γkBT3) which connects the contrasting J T2 in the conventional Schottky interface and the J T3 scaling in graphene-based Schottky interface via a non-parabolicity parameter, γ. For N-layer graphene of ABC -stacking and of ABA -stacking, the scaling relation follows J T 2 / N + 1 and J T3 respectively. Intriguingly, the Richardson constant extracted from the experimental data using an incorrect scaling can differ with the actual value by more than two orders of magnitude. Our results highlights the importance of using the correct scaling relation in order to accurately extract important physical properties, such as the Richardson constant and the Schottky barrier's height.

Health behaviors of Korean female nursing students in relation to obesity and osteoporosis.

PubMed

Park, Da-In; Choi-Kwon, Smi; Han, Kihye

2015-01-01

It has been reported that young adults' dietary habits and health behaviors have significant effects on obesity and bone health. However, there is a lack of thorough understanding of the prevalence of unhealthy behaviors and potential relationships to obesity and osteoporosis among young females. This cross-sectional study examined dietary habits, health behaviors, anthropometric measurements, and bone mineral density of 160 female nursing students. A relatively large number of students had vitamin D (n = 104, 65%) and calcium (n = 84, 52.5%) deficiencies but displayed excessive cholesterol (n = 86, 53.8%) and sodium (n = 137, 85.6%) intakes. Unhealthy dietary and health habits such as nighttime snacking, coffee drinking, low milk drinking, and lack of exercise were also noted. Despite their knowledge on health, a large portion of nursing students displayed unhealthy dietary habits and health. Tailored strategies and education to narrow the gap between health behavioral knowledge and practice are urgently needed. Copyright © 2015 Elsevier Inc. All rights reserved.

A comparison of current practice patterns of US dermatologists versus published guidelines for the biopsy, initial management, and follow up of patients with primary cutaneous melanoma.

PubMed

Farberg, Aaron S; Rigel, Darrell S

2016-12-01

Guidelines exist for the management of cutaneous malignant melanoma, but their adoption, prevalence, and impact have not yet been determined. To determine current melanoma clinical management practices of US dermatologists and the variance from guidelines that might exist. A cross-sectional e-mail survey study assessing preferred biopsy methods for lesions suspicious for melanoma, margins used for excision, and recommended follow-up intervals were sent to 6177 US dermatologists (540 responding). The representative nature of the responding subset was verified by comparing their demographics to that from the American Academy of Dermatology (AAD) membership. Management varied from published guidelines. Shave biopsy (35%) was the most commonly used method followed by narrow excisional biopsy (31%), saucerization/scoop shave (12%), punch (11%), and wide excision (3%). Excisional margins narrower than recommended were noted and follow-up intervals varied. There were significant management differences noted for dermatologists by practice setting and by years in practice. The impact of patient history, lesion anatomic site, and size of lesion were not assessed. Recall and nonresponder sampling bias may exist. Variations in dermatologists' approaches to melanoma management and variance from current guidelines suggest that a knowledge gap may exist representing an educational opportunity. However, emerging data may also justify deviations from existing guidelines, suggesting a reassessment of the guidelines may be indicated. Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Influence of laser beam incidence angle on laser lap welding quality of galvanized steels

NASA Astrophysics Data System (ADS)

Mei, Lifang; Yan, Dongbing; Chen, Genyu; Wang, Zhenhui; Chen, Shuixuan

2017-11-01

Based on the characteristics of laser welded structural parts of auto bodies, the influence of variation in laser beam incidence angle on the lap welding performance of galvanized auto-body sheets was studied. Lap welding tests were carried out on the galvanized sheets for auto-body application at different laser beam incidence angles by using the optimal welding parameters obtained through orthogonal experiment. The effects of incidence angle variation on seam appearance, cross-sectional shape, joint mechanical properties and microstructure of weldments were analyzed. In addition, the main factors influencing the value of incidence angle were investigated. According to the results, the weld seams had a good appearance as well as a fine, and uniform microstructure when the laser beam incidence angle was smaller than the critical incidence angle, and thus they could withstand great tensile and shear loads. Moreover, all tensile-shear specimens were fractured in the base material zone. When the laser beam incidence angle was larger than the critical incidence angle, defects like shrinkage and collapse tended to emerge, thereby resulting in the deteriorated weldability of specimens. Meanwhile, factors like the type and thickness of sheet, weld width as well as inter-sheet gap all had a certain effect on the value of laser beam incidence angle. When the sheet thickness was small and the weld width was narrow, the laser beam incidence angle could be increased appropriately. At the same time, small changes in the inter-sheet gap could greatly impact the value of incidence angle. When the inter-sheet gap was small, the laser beam incidence angle should not be too large.

Gender differences in health information behaviour: a Finnish population-based survey.

PubMed

Ek, Stefan

2015-09-01

Narrowing the gaps in health outcomes, including those between men and women, has been a pronounced goal on the agenda of the Finnish health authorities since the mid-1980s. But still there is a huge gap in favour of women when it comes to life expectancy at birth. People's health information behaviour, that is how people seek, obtain, evaluate, categorize and use relevant health-related information to perform desired health behaviours, is a critical prerequisite to appropriate and consistent performances of these behaviours. With respect to gender, it has been noted that men often are unwilling and lack the motivation to engage with health-related information. The purpose of this study was to investigate how gender affects health information behaviour in the Finnish population aged 18-65 years. The survey data were collected via a questionnaire which was posted to a representative cross section consisting of 1500 Finnish citizens. The statistical analysis consists of ANOVA F-tests and Fisher's exact tests. The results show that women were more interested in and reported much more active seeking of health-related information, paid more attention to potential worldwide pandemics and were much more attentive as to how the goods they purchase in everyday life affect their health than men did. Women also reported receiving far more informal health-related information from close family members, other kin and friends/workmates than men did. Thus, to succeed in public health promotion and interventions the measures taken should be much more sensitive to the gender gap in health information behaviour. © The Author (2013). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Gap Flows through Idealized Topography. Part I: Forcing by Large-Scale Winds in the Nonrotating Limit.

NASA Astrophysics Data System (ADS)

Gabersek, Sasa.; Durran, Dale R.

2004-12-01

Gap winds produced by a uniform airstream flowing over an isolated flat-top ridge cut by a straight narrow gap are investigated by numerical simulation. On the scale of the entire barrier, the proportion of the oncoming flow that passes through the gap is relatively independent of the nondimensional mountain height , even over that range of for which there is the previously documented transition from a “flow over the ridge” regime to a “flow around” regime.The kinematics and dynamics of the gap flow itself were investigated by examining mass and momentum budgets for control volumes at the entrance, central, and exit regions of the gap. These analyses suggest three basic behaviors: the linear regime (small ) in which there is essentially no enhancement of the gap flow; the mountain wave regime ( 1.5) in which vertical mass and momentum fluxes play a crucial role in creating very strong winds near the exit of the gap; and the upstream-blocking regime ( 5) in which lateral convergence generates the strongest winds near the entrance of the gap.Trajectory analysis of the flow in the strongest events, the mountain wave events, confirms the importance of net subsidence in creating high wind speeds. Neglect of vertical motion in applications of Bernoulli's equation to gap flows is shown to lead to unreasonable wind speed predictions whenever the temperature at the gap exit exceeds that at the gap entrance. The distribution of the Bernoulli function on an isentropic surface shows a correspondence between regions of high Bernoulli function and high wind speeds in the gap-exit jet similar to that previously documented for shallow-water flow.

Simplified Structure of Ducted Darrieus-Type Hydro Turbine with Narrow Intake for Extra-low Head Hydropower Utilization

NASA Astrophysics Data System (ADS)

Matsushita, Daisuke; Okuma, Kusuo; Watanabe, Satoshi; Furukawa, Akinori

A ducted Darrieus-type hydro turbine has been proposed for extra-low head hydropower utilization of total head less than 2m, where development is almost not done in the commercial base. Though the efficiency of Darrieus-type turbine, which is cross flow type, is not so high as conventional type, the Darrieus-type has a cost-advantage due to the simple structure. By installing a narrow intake at upstream of the runner, the efficiency becomes higher than normal intake that a width of which is the same as one of runner section. In the case of normal intake, the casing clearance between the runner pitch circle and the side-wall at the runner section becomes the influential factor which deteriorates the efficiency. On the other hand, in the case of narrow intake, it is possible to keep efficiency high, based on the fact that the distorting flow to the clearance is prevented. In the present paper, the effects of narrow intake and draft tube on turbine performance are experimentally examined and the design guideline of simplified structure for ducted Darrieus-type turbine with narrow intake is proposed.

Changes in the Response Properties of Inferior Colliculus Neurons Relating to Tinnitus

PubMed Central

Berger, Joel I.; Coomber, Ben; Wells, Tobias T.; Wallace, Mark N.; Palmer, Alan R.

2014-01-01

Tinnitus is often identified in animal models by using the gap prepulse inhibition of acoustic startle. Impaired gap detection following acoustic over-exposure (AOE) is thought to be caused by tinnitus “filling in” the gap, thus, reducing its salience. This presumably involves altered perception, and could conceivably be caused by changes at the level of the neocortex, i.e., cortical reorganization. Alternatively, reduced gap detection ability might reflect poorer temporal processing in the brainstem, caused by AOE; in which case, impaired gap detection would not be a reliable indicator of tinnitus. We tested the latter hypothesis by examining gap detection in inferior colliculus (IC) neurons following AOE. Seven of nine unilaterally noise-exposed guinea pigs exhibited behavioral evidence of tinnitus. In these tinnitus animals, neural gap detection thresholds (GDTs) in the IC significantly increased in response to broadband noise stimuli, but not to pure tones or narrow-band noise. In addition, when IC neurons were sub-divided according to temporal response profile (onset vs. sustained firing patterns), we found a significant increase in the proportion of onset-type responses after AOE. Importantly, however, GDTs were still considerably shorter than gap durations commonly used in objective behavioral tests for tinnitus. These data indicate that the neural changes observed in the IC are insufficient to explain deficits in behavioral gap detection that are commonly attributed to tinnitus. The subtle changes in IC neuron response profiles following AOE warrant further investigation. PMID:25346722

Association of narrow angles with anterior chamber area and volume measured with anterior-segment optical coherence tomography.

PubMed

Wu, Ren-Yi; Nongpiur, Monisha E; He, Ming-Guang; Sakata, Lisandro M; Friedman, David S; Chan, Yiong-Huak; Lavanya, Raghavan; Wong, Tien-Yin; Aung, Tin

2011-05-01

To describe the measurement of anterior chamber area and anterior chamber volume by anterior-segment optical coherence tomography and to investigate the association of these parameters with the presence of narrow angles. This was a cross-sectional study of subjects aged at least 50 years without ophthalmic symptoms recruited from a community clinic. All participants underwent standardized ocular examination and anterior-segment optical coherence tomography. Customized software was used to measure anterior chamber area (cross-sectional area bounded by the corneal endothelium, anterior surface of iris, and lens within the pupil) and anterior chamber volume (calculated by rotating the anterior chamber area 360° around a vertical axis through the midpoint of the anterior chamber area). An eye was considered to have narrow angles if the posterior pigmented trabecular meshwork was not visible for at least 180° on gonioscopy with the eye in the primary position. A total of 1922 subjects were included in the final analyses, 317 (16.5%) of whom had narrow angles. Mean anterior chamber area (15.6 vs 21.1 mm(2); P < .001) and anterior chamber volume (97.6 vs 142.1 mm(3); P < .001) were smaller in eyes with narrow angles compared with those in eyes without narrow angles. After adjusting for age, sex, anterior chamber depth, axial length, and pupil size, smaller anterior chamber area (odds ratio, 53.2; 95% confidence interval, 27.1-104.5) and anterior chamber volume (odds ratio, 40.2; 95% confidence interval, 21.5-75.2) were significantly associated with the presence of narrow angles. Smaller anterior chamber area and anterior chamber volume were independently associated with narrow angles in Singaporeans, even after controlling for other known ocular risk factors.

Perceived challenges and opportunities arising from integration of mental health into primary care: a cross-sectional survey of primary health care workers in south-west Ethiopia

PubMed Central

2014-01-01

Background The WHO’s mental health Gap Action Programme seeks to narrow the treatment gap for mental disorders by advocating integration of mental health into primary health care (PHC). This study aimed to assess the challenges and opportunities of this approach from the perspective of PHC workers in a sub-Saharan African country. Methods A facility-based cross-sectional survey of 151 PHC workers was conducted from 1st to 30th November 2011 in Jimma zone, south-west Ethiopia. A structured questionnaire was used to ask about past training and mental health experience, knowledge and attitudes towards mental disorders and provision of mental health care in PHC. Semi-structured interviews were carried out with 12 heads of health facilities for more in-depth understanding. Results Almost all PHC workers (96.0%) reported that mental health care was important in Ethiopia and the majority (66.9%) expressed interest in actually delivering mental health care. Higher levels of general health training (degree vs. diploma) and pre-service clinical exposure to mental health care were associated with more favourable attitudes. Knowledge about mental disorder diagnoses, symptoms and treatments was low. Almost half (45.0%) of PHC workers reported that supernatural factors were important causes of mental disorders. Health system and structural issues, such as poor medication supply, lack of rooms, time constraints, absence of specialist supervision and lack of treatment guidelines, were identified as challenges. Almost all PHC workers (96.7%) reported a need for more training, including a clinical attachment, in order to be able to deliver mental health care competently. Conclusions Despite acceptability to PHC workers, the feasibility of integrating mental health into PHC in this sub-Saharan African setting is limited by important gaps in PHC worker knowledge and expectations regarding mental health care, coupled with health system constraints. In addition to clinically-based refresher mental health training, expansion of the specialist mental health workforce may be needed to support integration in practice. PMID:24602215

Perceived challenges and opportunities arising from integration of mental health into primary care: a cross-sectional survey of primary health care workers in south-west Ethiopia.

PubMed

Abera, Mubarek; Tesfaye, Markos; Belachew, Tefera; Hanlon, Charlotte

2014-03-06

The WHO's mental health Gap Action Programme seeks to narrow the treatment gap for mental disorders by advocating integration of mental health into primary health care (PHC). This study aimed to assess the challenges and opportunities of this approach from the perspective of PHC workers in a sub-Saharan African country. A facility-based cross-sectional survey of 151 PHC workers was conducted from 1st to 30th November 2011 in Jimma zone, south-west Ethiopia. A structured questionnaire was used to ask about past training and mental health experience, knowledge and attitudes towards mental disorders and provision of mental health care in PHC. Semi-structured interviews were carried out with 12 heads of health facilities for more in-depth understanding. Almost all PHC workers (96.0%) reported that mental health care was important in Ethiopia and the majority (66.9%) expressed interest in actually delivering mental health care. Higher levels of general health training (degree vs. diploma) and pre-service clinical exposure to mental health care were associated with more favourable attitudes. Knowledge about mental disorder diagnoses, symptoms and treatments was low. Almost half (45.0%) of PHC workers reported that supernatural factors were important causes of mental disorders. Health system and structural issues, such as poor medication supply, lack of rooms, time constraints, absence of specialist supervision and lack of treatment guidelines, were identified as challenges. Almost all PHC workers (96.7%) reported a need for more training, including a clinical attachment, in order to be able to deliver mental health care competently. Despite acceptability to PHC workers, the feasibility of integrating mental health into PHC in this sub-Saharan African setting is limited by important gaps in PHC worker knowledge and expectations regarding mental health care, coupled with health system constraints. In addition to clinically-based refresher mental health training, expansion of the specialist mental health workforce may be needed to support integration in practice.

Searching for the Golden Model of Education: Cross-National Analysis of Math Achievement

PubMed Central

Bodovski, Katerina; Byun, Soo-yong; Chykina, Volha; Chung, Hee Jin

2017-01-01

We utilized four waves of TIMSS data in addition to the information we have collected on countries’ educational systems to examine whether different degrees of standardization, differentiation, proportion of students in private schools and governmental spending on education influence students’ math achievement, its variation and socioeconomic status (SES) gaps in math achievement. Findings: A higher level of standardization of educational systems was associated with higher average math achievement. Greater expenditure on education (as % of total government expenditure) was associated with a lower level of dispersion of math achievement and smaller SES gaps in math achievement. Wealthier countries exhibited higher average math achievement and a narrower variation. Higher income inequality (measured by Gini index) was associated with a lower average math achievement and larger SES gaps. Further, we found that higher level of standardization alleviates the negative effects of differentiation in the systems with more rigid tracking. PMID:29151667

BC8 Silicon (Si-III) is a Narrow-Gap Semiconductor

NASA Astrophysics Data System (ADS)

Zhang, Haidong; Liu, Hanyu; Wei, Kaya; Kurakevych, Oleksandr O.; Le Godec, Yann; Liu, Zhenxian; Martin, Joshua; Guerrette, Michael; Nolas, George S.; Strobel, Timothy A.

2017-04-01

Large-volume, phase-pure synthesis of BC8 silicon (I a 3 ¯ , c I 16 ) has enabled bulk measurements of optical, electronic, and thermal properties. Unlike previous reports that conclude BC8-Si is semimetallic, we demonstrate that this phase is a direct band gap semiconductor with a very small energy gap and moderate carrier concentration and mobility at room temperature, based on far- and midinfrared optical spectroscopy, temperature-dependent electrical conductivity, Seebeck and heat capacity measurements. Samples exhibit a plasma wavelength near 11 μ m , indicating potential for infrared plasmonic applications. Thermal conductivity is reduced by 1-2 orders of magnitude depending on temperature as compared with the diamond cubic (DC-Si) phase. The electronic structure and dielectric properties can be reproduced by first-principles calculations with hybrid functionals after adjusting the level of exact Hartree-Fock (HF) exchange mixing. These results clarify existing limited and controversial experimental data sets and ab initio calculations.

Ultrawide low frequency band gap of phononic crystal in nacreous composite material

NASA Astrophysics Data System (ADS)

Yin, J.; Huang, J.; Zhang, S.; Zhang, H. W.; Chen, B. S.

2014-06-01

The band structure of a nacreous composite material is studied by two proposed models, where an ultrawide low frequency band gap is observed. The first model (tension-shear chain model) with two phases including brick and mortar is investigated to describe the wave propagation in the nacreous composite material, and the dispersion relation is calculated by transfer matrix method and Bloch theorem. The results show that the frequency ranges of the pass bands are quite narrow, because a special tension-shear chain motion in the nacreous composite material is formed by some very slow modes. Furthermore, the second model (two-dimensional finite element model) is presented to investigate its band gap by a multi-level substructure scheme. Our findings will be of great value to the design and synthesis of vibration isolation materials in a wide and low frequency range. Finally, the transmission characteristics are calculated to verify the results.

Distribution of electron density and magnetocapacitance in the regime of the fractional quantum Hall effect

NASA Astrophysics Data System (ADS)

Pikus, F. G.; Efros, A. L.

1993-06-01

A two-dimensional electron liquid (TDEL), subjected to a smooth random potential, is studied in the regime of the fractional quantum Hall effect. An analytical theory of the nonlinear screening is presented for the case when the fractional gap is much less than the magnitude of the unscreened random potential. In this ``narrow-gap approximation'' (NGA), we calculate the electron density distribution function, the fraction of the TDEL which is in the incompressible state, and the thermodynamic density of states. The magnetocapacitance is calculated to compare with the recent experiments. The NGA is found to be not accurate enough to describe the data. The results for larger fractional gaps are obtained by computer modeling. To fit the recent experimental data we have also taken into account the anyon-anyon interaction in the vicinity of a fractional singularity.

Largely Enhanced Single-molecule Fluorescence in Plasmonic Nanogaps formed by Hybrid Silver Nanostructures

PubMed Central

Zhang, Jian; Lakowicz, Joseph R.

2013-01-01

It has been suggested that narrow gaps between metallic nanostructures can be practical for producing large field enhancement. We design a hybrid silver nanostructure geometry in which fluorescent emitters are sandwiched between silver nanoparticles and silver island film (SIF). A desired number of polyelectrolyte layers are deposited on the SIF surface before the self-assembly of a second silver nanoparticle layer. Layer-by-layer configuration provides a well-defined dye position. It allows us to study the photophyical behaviors of fluorophores in the resulting gap at the single molecule level. The enhancement factor of a fluorophore located in the gap is much higher than those on silver surfaces alone and on glass. These effects may be used for increased detectability of single molecules bound to surfaces which contain metallic structures for either biophysical studies or high sensitivity assays. PMID:23373787

A low speed two-dimensional study of flow separation on the GA(W)-1 airfoil with 30-percent chord Fowler flap

NASA Technical Reports Server (NTRS)

Seetharam, H. C.; Wentz, W. H., Jr.

1977-01-01

Measurements of flow fields with low speed turbulent boundary layers were made for the GA(W)-1 airfoil with a 0.30 c Fowler flap deflected 40 deg at angles of attack of 2.7 deg, 7.7 deg, and 12.8 deg, at a Reynolds number of 2.2 million, and a Mach number of 0.13. Details of velocity and pressure fields associated with the airfoil flap combination are presented for cases of narrow, optimum and wide slot gaps. Extensive flow field turbulence surveys were also conducted employing hot-film anemometry. For the optimum gap setting, the boundaries of the regions of flow reversal within the wake were determined by this technique for two angles of attack. Local skin friction distributions for the basic airfoil and the airfoil with flap (optimum gap) were obtained using the razor blade technique.

How Do Pre-Kindergarteners Spend Their Time? Gender, Ethnicity, and Income as Predictors of Experiences in Pre-Kindergarten Classrooms

ERIC Educational Resources Information Center

Early, Diane M.; Iruka, Iheoma U.; Ritchie, Sharon; Barbarin, Oscar A.; Winn, Donna-Marie C.; Crawford, Gisele M.; Frome, Pamela M.; Clifford, Richard M.; Burchinal, Margaret; Howes, Carollee; Bryant, Donna M.; Pianta, Robert C.

2010-01-01

The current paper considers how children spend their time in state-funded pre-kindergarten programs and how time use relates to ethnicity, gender, and family income, based on the assumption that how time is spent in pre-kindergarten is relevant for the programs' success in narrowing achievement gaps. Classroom observations of 2061 children in 652…

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

ERIC Educational Resources Information Center

Kober, Nancy; McMurrer, Jennifer; Silva, Malini R.

2011-01-01

Title I provides extra instructional services designed to raise achievement for low-performing students in schools with relatively high poverty rates, and for all students in many of the nation's highest-poverty schools. To learn more about how well Title I students are performing academically, the Center on Education Policy (CEP) compared…

Increasing the Options. A Report of the Task Force on Southern Rural Development, Southern Regional Council.

ERIC Educational Resources Information Center

Southern Regional Council, Atlanta, GA.

Monumental changes have occurred in the South, i.e., the loss of many farm and nonfarm residents to urban areas, farms becoming larger and more mechanized, the growth of manufacturing employment, and the narrowing of income gaps between rural and urban areas, and between the South and the non-South. Political and social changes have accompanied…

The Narrowing Gap in New York City Teacher Qualifications and Its Implications for Student Achievement in High-Poverty Schools. Working Paper 10

ERIC Educational Resources Information Center

Boyd, Donald; Lankford, Hamilton; Loeb, Susanna; Rockoff, Jonah; Wyckoff, James

2007-01-01

Studies have found substantial sorting of teachers across schools, with the schools with the highest proportions of poor, non-white, and low-scoring students having the least qualified teachers as measured by certification, exam performance, and inexperience (Lankford, Loeb and Wyckoff, 2002). Yet, there have been substantial changes in the…

Ecologies of Educational Reflexivity and Agency--A Different Way of Thinking about Equitable Educational Policies and Practices for England and Beyond?

ERIC Educational Resources Information Center

Raffo, Carlo; Forbes, Claire; Thomson, Steph

2015-01-01

By placing emphasis on equity and social mobility, the current UK education policy for England focuses on narrowing the educational attainment gap between more and less advantaged groups of young people--an approach that has strong parallels in many other Anglophone countries around the world. We argue that these policy and associated practice…

Selective CO2 conversion to formate in water using a CZTS photocathode modified with a ruthenium complex polymer.

PubMed

Arai, Takeo; Tajima, Shin; Sato, Shunsuke; Uemura, Keiko; Morikawa, Takeshi; Kajino, Tsutomu

2011-12-21

Highly selective photoelectrochemical CO(2) reduction (>80% selectivity) in water was successfully achieved by combining Cu(2)ZnSnS(4) (CZTS) with a metal-complex electrocatalyst. CZTS, a sulfide semiconductor that possesses a narrow band gap and consists of earth-abundant elements, is demonstrated to be a candidate photoabsorber for a CO(2) reduction hybrid photocatalyst.

Tools for Employers: Making Equal Pay a Reality in Your Workplace. Facts on Working Women.

ERIC Educational Resources Information Center

Women's Bureau (DOL), Washington, DC.

This publication presents six primary tools employers can use to narrow or eliminate pay gaps in their workplaces. After each tool is a discussion of the problem and examples of "best practices" by employers that have won the Department of Labor's Opportunity 2000 and EVE (Exemplary Voluntary Efforts) awards. The report is divided into six tools:…

Review of Sample Size for Structural Equation Models in Second Language Testing and Learning Research: A Monte Carlo Approach

ERIC Educational Resources Information Center

In'nami, Yo; Koizumi, Rie

2013-01-01

The importance of sample size, although widely discussed in the literature on structural equation modeling (SEM), has not been widely recognized among applied SEM researchers. To narrow this gap, we focus on second language testing and learning studies and examine the following: (a) Is the sample size sufficient in terms of precision and power of…

Do Some Schools Narrow the Gap? Differential School Effectiveness by Ethnicity, Gender, Poverty, and Prior Achievement

ERIC Educational Resources Information Center

Strand, Steve

2010-01-01

This study analyses the educational progress of an entire national cohort of over 530,000 pupils in England between age 7 in 2000 and age 11 in 2004. The results show that Black Caribbean boys not entitled to free school meals, and particularly the more able pupils, made significantly less progress than their White British peers. There is no…

Performance of a Group of Deaf and Hard-of-Hearing Students and a Comparison Group of Hearing Students on a Series of Problem-Solving Tasks.

ERIC Educational Resources Information Center

Luckner, John L.; McNeill, Joyce H.

1994-01-01

This study found that 43 school-age deaf and hard-of-hearing students did not perform as well as a matched group of hearing students on problem-solving tasks. As they got older, both groups made incremental gains in problem-solving ability, and the gap between groups narrowed. (Author/JDD)

Do Electronic Technologies Increase or Narrow Differences in Higher Education Quality between Low- and High-Income Countries?

ERIC Educational Resources Information Center

Capshaw, Norman Clark

2008-01-01

The disruptive technologies of the Internet and computers are changing our world in myriad ways. These technologies are also increasingly being employed in higher education but to what effect? Are the effects on higher education quality measurable, and if so, what is the effect on the traditional gap between high-income and low- to middle-income…

The Education Challenge in Mexico: Delivering Good Quality Education to All. OECD Economics Department Working Papers, No. 447

ERIC Educational Resources Information Center

Guichard, Stephanie

2005-01-01

The growth of potential GDP in Mexico is not fast enough to narrow the income gap with other OECD countries at a sufficient pace. The persistent weakness in human capital development contributes to this situation. In particular, Mexicans spend comparatively few years in formal education, and the quality of the education they receive is lower than…

Bridging the Gap: Solving Spatial Means-Ends Relations in a Locomotor Task

ERIC Educational Resources Information Center

Berger, Sarah E.; Adolph, Karen E.; Kavookjian, Alisan E.

2010-01-01

Using a means-means-ends problem-solving task, this study examined whether 16-month-old walking infants (N = 28) took into account the width of a bridge as a means for crossing a precipice and the location of a handrail as a means for augmenting balance on a narrow bridge. Infants were encouraged to cross from one platform to another over narrow…

Girl Talk: A Qualitative Study of Girls Talking about the Meaning of Their Lives in an Urban Single-Sex Elementary School

ERIC Educational Resources Information Center

Ridenour, Carolyn S.; Hassell Hughes, Sheila

2016-01-01

The suburban-urban achievement gap (diminishing until the 1980s) has stopped its narrowing trend, and single-sex schools are proliferating as a reform model, especially in urban areas. In this study researchers interviewed eight elementary school girls (in an all-girls school) three times over 2 years, and the resulting 23 transcripts were…