Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Data Brief ; 48: 109274, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37383786

RESUMO

Large sample datasets of in situ evapotranspiration (ET) measurements with well documented data provenance and quality assurance are critical for water management and many fields of earth science research. We present a post-processed ET oriented dataset at daily and monthly timesteps, from 161 stations, including 148 eddy covariance flux towers, that were chosen based on their data quality from nearly 350 stations across the contiguous United States. In addition to ET, the data includes energy and heat fluxes, meteorological measurements, and reference ET downloaded from gridMET for each flux station. Data processing techniques were conducted in a reproducible manner using open-source software. Most data initially came from the public AmeriFlux network, however, several different networks (e.g., the USDA-Agricultural Research Service) and university partners provided data that was not yet public. Initial half-hourly energy balance data were gap-filled and aggregated to daily frequency, and turbulent fluxes were corrected for energy balance closure error using the FLUXNET2015/ONEFlux energy balance ratio approach. Metadata, diagnostics of energy balance, and interactive graphs of time series data are included for each station. Although the dataset was developed primarily to benchmark satellite-based remote sensing ET models of the OpenET initiative, there are many other potential uses, such as validation for a range of regional hydrologic and atmospheric models.

2.
Plant Dis ; 101(9): 1621-1626, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30677333

RESUMO

Wheat streak mosaic (WSM) caused by Wheat streak mosaic virus, which is transmitted by the wheat curl mite (Aceria tosichella), is a major yield-limiting disease in the Texas High Plains. In addition to its impact on grain production, the disease reduces water-use efficiency by affecting root development. Because of the declining Ogallala Aquifer water level, water conservation has become one of the major pressing issues in the region. Thus, questions are often raised as to whether it is worthwhile to irrigate infected fields in light of the water conservation issues, associated energy costs, and current wheat prices. To address some of these questions, field experiments were conducted in 2013 and 2016 at two separate locations to determine whether grain yield could be predicted from disease severity levels, assessed early in the spring, for potential use as a decision tool for crop management, including irrigation. In both fields, disease severity assessments started in April, using a handheld hyperspectral radiometer with which reflectance measurements were taken weekly in multiple plots in arbitrarily selected locations across the fields. The relationship between WSM severity levels and grain yield for the different assessment dates were determined by fitting reflectance and yield values into the logistic regression function. The model predicted yield levels with r2 values ranging from 0.67 to 0.85 (P < 0.0001), indicating that the impact of WSM on grain yield could be fairly well predicted from early assessments of WSM severity levels. As the disease is normally progressive over time, this type of information will be useful for making management decisions of whether to continue irrigating infected fields, especially if combined with an economic threshold for WSM severity levels.


Assuntos
Doenças das Plantas , Potyviridae , Triticum , Agricultura , Animais , Grão Comestível/virologia , Ácaros/virologia , Doenças das Plantas/prevenção & controle , Doenças das Plantas/virologia , Potyviridae/fisiologia , Texas , Triticum/crescimento & desenvolvimento , Triticum/virologia
3.
Plant Dis ; 94(6): 766-770, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30754301

RESUMO

Greenhouse and field studies were conducted to determine the effects of Wheat streak mosaic virus (WSMV), a member of the family Potyviridae, on root development and water-use efficiency (WUE) of two hard red winter wheat (Triticum aestivum) cultivars, one susceptible and one resistant to WSMV. In the greenhouse studies, wheat cultivars were grown under three water regimes of 30, 60, and 80% soil saturation capacity. After inoculation with WSMV, plants were grown for approximately 4 weeks and then harvested. Root and shoot weights were measured to determine the effect of the disease on biomass. In all water treatments, root biomass and WUE of inoculated susceptible plants were significantly less (P < 0.05) than those of the noninoculated control plants. However, in the resistant cultivar, significance was only found in the 30 and 60% treatments for root weight and WUE, respectively. Field studies were also conducted under three water regimes based on reference evapotranspiration rates. Significant reductions in forage, grain yield, and crop WUE were observed in the inoculated susceptible plots compared with the noninoculated plots. Both studies demonstrated that wheat streak mosaic reduces WUE, which is a major concern in the Texas Panhandle because of limited availability of water.

4.
J Homosex ; 42(2): 21-43, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-12013573

RESUMO

In two studies, lesbians, gay men and bisexuals were queried concerning mistakes that well-meaning heterosexual people have made when interacting with them. In qualitative, open-ended research, we determined that the most common mistakes concerned heterosexuals' pointing out that they know someone who is gay, emphasizing their lack of prejudice, and relying on stereotypes about gays. Following up with a quantitative, close-ended questionnaire, we determined that the mistakes respondents experienced most often involved heterosexuals (a) relying on stereotypes and (b) ignoring gay issues; the most annoying mistakes were heterosexuals (a) using subtle prejudicial language and (b) not owning up to their discomfort with gay issues. We used two theoretical perspectives, shared reality theory and the contact hypothesis, to analyze the quantitative responses. Implications for intergroup relationships between heterosexual people and gay people are discussed.


Assuntos
Homossexualidade , Preconceito , Adulto , Feminino , Heterossexualidade , Humanos , Relações Interpessoais , Masculino , Inquéritos e Questionários
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...