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OALib Journal期刊

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Spanish-Language Home Visitation to Disadvantaged Latino Preschoolers: A Means of Promoting Language Development and English School Readiness  [PDF]
Virginia Mann
Creative Education (CE) , 2014, DOI: 10.4236/ce.2014.56051
Abstract:

This study reports five years of a school readiness intervention called “HABLA” (Home Based Activities Building Language Acquisition), designed to increase and enrich speech and literacy activities in the homes of economically and educationally disadvantaged Latino families with children between the age of 2 and 4. A team of trained home visitors provided two years of a 23-week program of visitation in which they met with parent(s) and child twice weekly. Both years presented a Spanish language adaptation of the parent-child home program model; home visitors provide intensive modeling and coaching of non-directive Spanish language use, conversation, and literacy activities. Administration of the PLS-3 in Spanish at the onset and culmination of each year of the program indicates significant increases in receptive and expressive language for each year of visitation (7.8 standard points for the first year, 4.4 for the second) with effect-size r ranging from .24 to 42. Participants had significantly improved their levels of oral Spanish skill and scored much higher than a comparison group of non-treated. A subset of graduates of the two-year program was tested as kindergarteners; they showed a continued advantage over a comparison group of 18 peers who had not received the intervention. For the graduates, both their Spanish PLS-3 scores and English PLS-4 scores were significantly higher, and their parents reported a continued effort to provide literacy experiences at home. The HABLA participants also showed a clear advantage for an English language test of phonological awareness, one of the strongest predictors of school success.

Characterization of Genotypic Mutations and Antiretroviral Resistance among Viremic HIV-Infected Patients in a High HIV Prevalence Area: Treatment Challenge and Transmission Risk  [PDF]
AliAsad Arastu, Virginia Kan
World Journal of AIDS (WJA) , 2011, DOI: 10.4236/wja.2011.13011
Abstract: There have been few reports evaluating the prevalence of genotypic mutations and antiretroviral resistance among chronic HIV-infected Veterans within the United States. This retrospective cross-sectional study characterizes the rates and changes in HIV genotypic mutations and antiretroviral resistance among viremic patients from 2001 to 2006 at the VA Medical Center located in Washington, DC. The District of Columbia is the metropolitan area with the highest HIV prevalence within the United States. De-identified, linked HIV RNA, genotypic reverse transcriptase (RT) and protease (Pr) mutations and antiretroviral resistance results were assessed for changes during the 6-year period. Aggregated clinic and antiretroviral utilization, and HIV acquisition risk data were evaluated for patients in care during this time. Among 990 viremic samples, the rate of any detected RT or Pr mutation fell from 100% in 2001 to 95% in 2006. This was primarily attributable to the 15% - 20% decrease seen for RT gene mutations against nucleoside/nucleotide class and non-nucleoside class during this period. Resistance to didanosine, stavudine, zidovudine, nevirapine and efavirenz decreased, and tenofovir resistance increased. Despite stable rates of Pr gene mutations, atazanavir resistance increased by 22% from 2003 to 2006. Some but not all changes in genotypic mutations and resistance patterns reflected our patients’ antiretroviral drug utilization. As sexual contacts (77%) and injection drug use (22%) were the leading acquisition risks disclosed by our HIV-infected patients, the high prevalence and changing patterns of HIV genotypic mutations and drug resistance among these patients have had pivotal impacts not only on HIV treatment but potential transmission into our community.
Carbon Capture and Storage and the UNFCCC: Recommendations to Address Trans-Boundary Issues  [PDF]
Viviane Romeiro, Virginia Parente
Low Carbon Economy (LCE) , 2012, DOI: 10.4236/lce.2012.323017
Abstract: This paper is mainly focused on the eligibility of trans-boundary Carbon Dioxide Capture and Storage (CCS) as a Clean Development Mechanism (CDM) project activity and it aims to explore a broad range of CCS transboundary issues whereby the United Nations Framework Convention on Climate Change (UNFCCC) and national governments could take into consideration. Much work is still to be done by the CCS community (including the Institute) to ensure that the implementation of CCS under the CDM is both environmentally effective and commercially attractive. The recommendations focus on technical issues, with the aim of helping Parties evaluate a robust strategy for CCS as part of international negotiations and establish CCS best practice criteria for governments and the international process, thereby enhancing transparency and ensuring that CCS deployment is safe and effective. When considering CDM projects activities with a transboundary component, it is recommend that the rules of the main international treaties related to CCS be considered by the UNFCCC, especially the London Protocol guidelines for risk assessment and management and the 2006 IPCC Guidelines. Additionally, national governments should apply the rules and guidelines as delineated under the relevant existing international treaties and CCS national regulations.
Water Stress Estimation from NDVI-Ts Plot and the Wet Environment Evapotranspiration  [PDF]
Daniela Girolimetto, Virginia Venturini
Advances in Remote Sensing (ARS) , 2013, DOI: 10.4236/ars.2013.24031
Abstract:

In this work we present a new simple index to estimate water stress (WS) for different types of surfaces, from remotely sensed data. We derive a WS index, named WSIEw, modifying the Water Deficit Index (WDI) proposed by Moran et al. by using the wet environment evapotranspiration (Ew) instead of the potential evapotranspiration (Epot) concept. Jiang and Islam model was used to simulate actual evapotranspiration (ET) and Priestley and Taylor equation to estimate Ew. The WSIEw results were compared to ground observations of ET, precipitation (PP), soil temperature (Tsoil) and soil moisture (SM) in the Southern Great Plains-EEUU. Preliminary results suggest the method is sensitive to the water status of different surfaces. However, the WSIEw would range from 0 to 0.7, having a value of 0.4 for a dry surface with 5% of SM. The methodology is operationally

Induced Currents in Pipelines  [PDF]
Virginia Mabel Silbergleit
Engineering (ENG) , 2015, DOI: 10.4236/eng.2015.75018
Abstract: Changes in the geomagnetic field produce ground induced currents that can have impacts on artificial systems such as pipelines. According to these, geomagnetic perturbations observed during June 2005 are studied. The data measured on the Ottawa River Valley pipeline verify the appearance of induced currents greater than 700 mA and additional potential values larger than ?850 V that can produce additional corrosive effects.
Synergistic Effect of Fullerene-Capped Gold Nanoparticles on Graphene Electrochemical Supercapacitors  [PDF]
Virginia Yong, H. Thomas Hahn
Advances in Nanoparticles (ANP) , 2013, DOI: 10.4236/anp.2013.21001
Abstract:

We report the synthesis of graphene/fullerene-capped gold nanoparticle nanocomposite film which was used to construct supercapacitor electrodes. The fullerene-based self-assembled monolayers on gold nanoparticles (AuNPs) were attained via the fullerene(C60)-gold interaction. The fullerene-capped AuNPs effectively separated the graphene sheets preventing aggregation. A synergistic effect was observed—the specific capacitance of graphene/fullerene-capped AuNP electrode is197 F/g, which is higher than that of graphene electrode (31 F/g), graphene/AuNP electrode (126 F/g), and graphene/fullerene electrode (118 F/g). The results render a novel route of synthesis and modification of graphene-based materials for the construction of electrochemical energy storage devices.

Variance reduction trends on ‘boosted’ classifiers
Virginia Wheway
Advances in Decision Sciences , 2004, DOI: 10.1155/s1173912604000094
Abstract: Ensemble classification techniques such as bagging, (Breiman, 1996a), boosting (Freund & Schapire, 1997) and arcing algorithms (Breiman, 1997) have received much attention in recent literature. Such techniques have been shown to lead to reduced classification error on unseen cases. Even when the ensemble is trained well beyond zero training set error, the ensemble continues to exhibit improved classification error on unseen cases. Despite many studies and conjectures, the reasons behind this improved performance and understanding of the underlying probabilistic structures remain open and challenging problems. More recently, diagnostics such as edge and margin (Breiman, 1997; Freund & Schapire, 1997; Schapire et al., 1998) have been used to explain the improvements made when ensemble classifiers are built. This paper presents some interesting results from an empirical study performed on a set of representative datasets using the decision tree learner C4.5 (Quinlan, 1993). An exponential-like decay in the variance of the edge is observed as the number of boosting trials is increased. i.e. boosting appears to ‘homogenise’ the edge. Some initial theory is presented which indicates that a lack of correlation between the errors of individual classifiers is a key factor in this variance reduction.
10 Reasons to be Tantalized by the B73 Maize Genome
Virginia Walbot
PLOS Genetics , 2009, DOI: 10.1371/journal.pgen.1000723
Abstract:
Beyond Neutrality—Ecology Finds Its Niche
Virginia Gewin
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0040278
Abstract:
Functional Genomics Thickens the Biological Plot
Virginia Gewin
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0030219
Abstract:
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