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1.
Appl Opt ; 61(14): 4215-4225, 2022 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-36256099

RESUMEN

During 2019, an infrared camera, the compact thermal imager (CTI), recorded 15 million images of the Earth from the International Space Station. CTI is based on strained-layer superlattice (SLS) detector technology. The camera covered the spectral range from 3 to 11 µm in two spectral channels, 3.3-5.4 and 7.8-10.7 µm. Individual image frames were 26×21km2 projected on the ground, with 82 m pixel resolution. A frame time of 2.54 s created continuous image swaths with a 13% along-track image overlap. Upper limits determined on the ground and in flight for the electronic offset, read noise, and dark current demonstrated the stability of the SLS detector and camera over many months. Temperature calibration was established using a combination of preflight and in-flight measurements. A narrowband approximation of temperature as a function of photon counts produced an analytic relationship covering a temperature range of 0°-400°C. Examples of CTI images illustrate temperature retrievals over sea ice, urban and agricultural areas, desert, and wildfires.

2.
bioRxiv ; 2022 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-36263064

RESUMEN

Oxysterols (i.e., oxidized cholesterol species) have complex roles in biology. 25-hydroxycholesterol (25HC), a product of activity of cholesterol-25-hydroxylase (CH25H) upon cholesterol, has recently been shown to be broadly antiviral, suggesting therapeutic potential against SARS-CoV-2. However, 25HC can also amplify inflammation and tissue injury and be converted by CYP7B1 to 7α,25HC, a lipid with chemoattractant activity via the G protein-coupled receptor, EBI2/GPR183. Here, using in vitro studies and two different murine models of SARS-CoV-2 infection, we investigate the effects of these two oxysterols on SARS-CoV-2 pneumonia. We show that while 25HC and enantiomeric-25HC are antiviral in vitro against human endemic coronavirus-229E, they did not inhibit SARS-CoV-2; nor did supplemental 25HC reduce pulmonary SARS-CoV-2 titers in the K18-human ACE2 mouse model in vivo. 25HC treatment also did not alter immune cell influx into the airway, airspace cytokines, lung pathology, weight loss, symptoms, or survival but was associated with increased airspace albumin, an indicator of microvascular injury, and increased plasma pro-inflammatory cytokines. Conversely, mice treated with the EBI2/GPR183 inhibitor NIBR189 displayed a modest increase in lung viral load only at late time points, but no change in weight loss. Consistent with these findings, although Ch25h was upregulated in the lungs of SARS-CoV-2-infected WT mice, lung viral titers and weight loss in Ch25h-/- and Gpr183-/- mice infected with the beta variant were similar to control animals. Taken together, endogenous 25-hydroxycholesterols do not significantly regulate early SARS-CoV-2 replication or pathogenesis and supplemental 25HC may have pro-injury rather than therapeutic effects in SARS-CoV-2 pneumonia.

3.
Science ; 253(5017): 299-300, 1991 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-17794695

RESUMEN

Data from polar-orbiting meteorological satellites have been used to determine the extent of the Sahara Desert and to document its interannual variation from 1980 to 1990. The Sahara Desert ranged from 8,633,000 square kilometers in 1980 to 9,982,000 square kilometers in 1984. The greatest annual north-south latitudinal movement of the southern Saharan boundary was 110 kilometers from 1984 to 1985 and resulted in a decrease in desert area of 724,000 square kilometers.

4.
Science ; 227(4685): 369-75, 1985 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-17815712

RESUMEN

Data from the advanced very-high-resolution radiometer sensor on the National Oceanic and Atmospheric Administration's operational series of meteorological satellites were used to classify land cover and monitor vegetation dynamics for Africa over a 19-month period. There was a correspondence between seasonal variations in the density and extent of green-leaf vegetation and the patterns of rainfall associated with the movement of the Intertropical Convergence Zone. Regional variations, such as the 1983 drought in the Sahel of westem Africa, were observed. Integration of the weekly satellite data with respect to time for a 12-month period produced a remotely sensed estimate of primary production based upon the density and duration of green-leaf biomass. Eight of the 21-day composited data sets covering an 11-month period were used to produce a general land-cover classification that corresponded well with those of existing maps.

5.
Science ; 235(4796): 1656-9, 1987 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-3823909

RESUMEN

Data from the advanced very high resolution radiometer on board the National Oceanic and Atmospheric Administration's polar-orbiting meteorological satellites have been used to infer ecological parameters associated with Rift Valley fever (RVF) viral activity in Kenya. An indicator of potential viral activity was produced from satellite data for two different ecological regions in Kenya, where RVF is enzootic. The correlation between the satellite-derived green vegetation index and the ecological parameters associated with RVF virus suggested that satellite data may become a forecasting tool for RVF in Kenya and, perhaps, in other areas of sub-Saharan Africa.


Asunto(s)
Fiebre del Valle del Rift/epidemiología , Animales , Métodos Epidemiológicos , Kenia , Matemática , Telecomunicaciones
6.
Science ; 211(4479): 281-3, 1981 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-17748026

RESUMEN

A self-contained, hand-held radiometer designed for field use has been constructed and tested. The 4.5-kilogram device, consisting of a strap-supported electronics module and a hand-held probe containing three sensors, is powered by flashlight and transistor radio batteries, uses two silicon and one lead sulfide detector, has three liquid-crystal displays, features sample-and-hold radiometric sampling, and is spectrally configured to Landsat-D's thematic mapper bands TM3 (0.63 to 0.69 micrometer), TM4 (0.76 to 0.90 micrometer), and TM5 (1.55 to 1.75 micrometers). The device was designed to collect ground-truth data for the thematic mapper and to facilitate ground-based, remote-sensing studies of natural materials in situ. Prototype instruments were extensively tested under laboratory and field conditions, with satisfactory results.

7.
Science ; 285(5426): 397-400, 1999 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-10411500

RESUMEN

All known Rift Valley fever virus outbreaks in East Africa from 1950 to May 1998, and probably earlier, followed periods of abnormally high rainfall. Analysis of this record and Pacific and Indian Ocean sea surface temperature anomalies, coupled with satellite normalized difference vegetation index data, shows that prediction of Rift Valley fever outbreaks may be made up to 5 months in advance of outbreaks in East Africa. Concurrent near-real-time monitoring with satellite normalized difference vegetation data may identify actual affected areas.


Asunto(s)
Clima , Brotes de Enfermedades , Predicción , Fiebre del Valle del Rift/epidemiología , Tiempo (Meteorología) , Animales , Humanos , Kenia/epidemiología , Océanos y Mares , Océano Pacífico , Lluvia , Fiebre del Valle del Rift/prevención & control , Fiebre del Valle del Rift/veterinaria , Temperatura
8.
Science ; 291(5513): 2594-7, 2001 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-11283369

RESUMEN

The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) provides global monthly measurements of both oceanic phytoplankton chlorophyll biomass and light harvesting by land plants. These measurements allowed the comparison of simultaneous ocean and land net primary production (NPP) responses to a major El Niño to La Niña transition. Between September 1997 and August 2000, biospheric NPP varied by 6 petagrams of carbon per year (from 111 to 117 petagrams of carbon per year). Increases in ocean NPP were pronounced in tropical regions where El Niño-Southern Oscillation (ENSO) impacts on upwelling and nutrient availability were greatest. Globally, land NPP did not exhibit a clear ENSO response, although regional changes were substantial.


Asunto(s)
Biomasa , Clorofila/análisis , Clima , Fotosíntesis , Fitoplancton/metabolismo , Plantas/metabolismo , Luz , Océanos y Mares , Fitoplancton/crecimiento & desarrollo , Desarrollo de la Planta , Estaciones del Año , Agua de Mar , Nave Espacial
10.
Rev Sci Instrum ; 89(10): 10J116, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30399907

RESUMEN

In situ probes are being developed to make direct, spatially resolved measurements of the ion energy spectra in the edge of tokamak plasmas while being easily replaced and requiring minimal resources. The ion spectrometers will consist of a combined collimator and energy analyzer fabricated from silicon and mated to a detector to yield a form factor of approximately 2.0 cm × 1.5 cm × 0.2 cm. Results of fabrication and testing of the combined collimator and energy analyzer element are presented.

11.
J Cosmet Sci ; 58(4): 375-83, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17728938

RESUMEN

Cationic cellulosic polymers find wide utility as benefit agents in shampoo. Deposition of these polymers onto hair has been shown to mend split-ends, improve appearance and wet combing, as well as provide controlled delivery of insoluble actives. The deposition is thought to be enhanced by the formation of a polymer/surfactant complex that phase-separates from the bulk solution upon dilution. A standard characterization method has been developed to characterize the coacervate formation upon dilution, but the test is time and material prohibitive. We have developed a semi-automated high throughput workflow to characterize the coacervate-forming behavior of different shampoo formulations. A procedure that allows testing of real use shampoo dilutions without first formulating a complete shampoo was identified. This procedure was adapted to a Tecan liquid handler by optimizing the parameters for liquid dispensing as well as for mixing. The high throughput workflow enabled preparation and testing of hundreds of formulations with different types and levels of cationic cellulosic polymers and surfactants, and for each formulation a haze diagram was constructed. Optimal formulations and their dilutions that give substantial coacervate formation (determined by haze measurements) were identified. Results from this high throughput workflow were shown to reproduce standard haze and bench-top turbidity measurements, and this workflow has the advantages of using less material and allowing more variables to be tested with significant time savings.


Asunto(s)
Celulosa/química , Preparaciones para el Cabello/química , Polímeros/química , Tensoactivos/química , Micelas , Nefelometría y Turbidimetría
13.
Environ Res Lett ; 11(9)2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32818037

RESUMEN

Charcoal production for urban energy consumption is a main driver of forest degradation in sub Saharan Africa. Urban growth projections for the continent suggest that the relevance of this process will increase in the coming decades. Forest degradation associated to charcoal production is difficult to monitor and commonly overlooked and underrepresented in forest cover change and carbon emission estimates. We use a multitemporal dataset of very high-resolution remote sensing images to map kiln locations in a representative study area of tropical woodlands in central Mozambique. The resulting maps provided a characterization of the spatial extent and temporal dynamics of charcoal production. Using an indirect approach we combine kiln maps and field information on charcoal making to describe the magnitude and intensity of forest degradation linked to charcoal production, including aboveground biomass and carbon emissions. Our findings reveal that forest degradation associated to charcoal production in the study area is largely independent from deforestation driven by agricultural expansion and that its impact on forest cover change is in the same order of magnitude as deforestation. Our work illustrates the feasibility of using estimates of urban charcoal consumption to establish a link between urban energy demands and forest degradation. This kind of approach has potential to reduce uncertainties in forest cover change and carbon emission assessments in sub-Saharan Africa.

14.
Bull Soc Pathol Exot ; 98(3): 239-43, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16267968

RESUMEN

Despite a century of confidence and optimism in modern medicine and technology inspired by their often successful prevention and control efforts, infectious diseases remain an omnipresent, conspicuous major challenge to public health. Effective detection and control of infectious diseases require predictive and proactive efficient methods that provide early warning of an epidemic activity. Of particular relevance to these efforts is linking information at the landscape and coarser scales to data at the scale of the epidemic activity. In recent years, landscape epidemiology has used satellite remote sensing and geographic information systems as the technology capable of providing, from local to global scales, spatial and temporal climatic patterns that may influence the intensity of a vector-borne disease and predicts risk conditions associated with an epidemic. This article provides a condensed, and selective look at classical material and recent research about remote sensing and GIS (geographic information system) applications in public health.


Asunto(s)
Clima , Control de Enfermedades Transmisibles/métodos , Enfermedades Transmisibles Emergentes/prevención & control , Monitoreo del Ambiente/métodos , Vigilancia de la Población , África Central/epidemiología , Animales , Enfermedades del Simio Antropoideo/epidemiología , Control de Enfermedades Transmisibles/instrumentación , Enfermedades Transmisibles/epidemiología , Enfermedades Transmisibles Emergentes/epidemiología , Brotes de Enfermedades , Reservorios de Enfermedades , Vectores de Enfermedades , Monitoreo del Ambiente/instrumentación , Monitoreo Epidemiológico , Predicción , Sistemas de Información Geográfica , Fiebre Hemorrágica Ebola/epidemiología , Fiebre Hemorrágica Ebola/prevención & control , Fiebre Hemorrágica Ebola/veterinaria , Humanos , Modelos Teóricos , Pan troglodytes/virología , Estaciones del Año , Nave Espacial , Topografía Médica , Clima Tropical
15.
Biotechniques ; 32(2): 322, 324, 326-9, 2002 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11848409

RESUMEN

The use of DNA microarrays has spanned numerous disciplines of life science research. Despite the volume of studies utilizing this technology, no consensus exists on basic issues such as the determination of significantly altered genes in a given experiment, often leading to either false-negative or false-positive data. In this report, we study the effect of dilution of biological alterations on the detection level of gene expression differences using cDNA microarrays. We propose that subtle alterations in transcript levels of genes below the 2-fold level should be considered when replicate hybridizations are performed, because these subtle gene expression changes may be due to a robust response in few cells. We measured the effect of dilution of gene expression and found that differences in gene expression between the two cell lines assayed (HaCaT and MCF-7) were detected even after a 20-fold dilution factor. These results better our understanding of biological alterations that comprise a relatively small percentage of an assayed organ and help in the interpretation of gene expression data.


Asunto(s)
Perfilación de la Expresión Génica , Análisis de Secuencia por Matrices de Oligonucleótidos , Línea Celular , ADN Complementario , Humanos , Sensibilidad y Especificidad
16.
Am J Trop Med Hyg ; 54(5): 530-6, 1996 May.
Artículo en Inglés | MEDLINE | ID: mdl-8644911

RESUMEN

Sandfly fever and leishmaniasis were major causes of infectious disease morbidity among military personnel deployed to the Middle East during World War II. Recently, leishmaniasis has been reported in the United Nations Multinational Forces and Observers in the Sinai. Despite these indications of endemicity, no cases of sandfly fever and only 31 cases of leishmaniasis have been identified among U.S. veterans of the Persian Gulf War. The distribution in the Persian Gulf of the vector, Phlebotomus papatasi, is thought to be highly dependent on environmental conditions, especially temperature and relative humidity. A computer model was developed using the occurrence of P. papatasi as the dependent variable and weather data as the independent variables. The results of this model indicated that the greatest sand fly activity and thus the highest risk of sandfly fever and leishmania infections occurred during the spring/summer months before U.S. troops were deployed to the Persian Gulf. Because the weather model produced probability of occurrence information for locations of the weather stations only, normalized difference vegetation index (NDVI) levels from remotely sensed Advanced Very High Resolution Radiometer satellites were determined for each weather station. From the results of the frequency of NDVI levels by probability of occurrence, the range of NDVI levels for presence of the vector was determined. The computer then identified all pixels within the NDVI range indicated and produced a computer-generated map of the probable distribution of P. papatasi. The resulting map expanded the analysis to areas where there were no weather stations and from which no information was reported in the literature, identifying these areas as having either a high or low probability of vector occurrence.


Asunto(s)
Simulación por Computador , Insectos Vectores/crecimiento & desarrollo , Phlebotomus/crecimiento & desarrollo , Comunicaciones por Satélite , Estaciones del Año , Temperatura , Animales , Asia Occidental , Demografía
17.
Dev Psychol ; 35(5): 1198-209, 1999 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10493646

RESUMEN

The relationships between adolescents' explanations for unemployment, poverty, and homelessness and their beliefs about opportunity, reports of family values, and personal aspirations were tested for 434 teenagers (mean age = 16 years 4 months). Explanations were coded for references to individual causes, societal causes, or both. Higher maternal education and average household income in the adolescent's school district were positively related to the likelihood of attributing all three problems to societal causes. When explaining unemployment, older adolescents noted both causes, and boys mentioned individual factors whereas girls mentioned societal factors. After adjustment for background factors, those endorsing individual causes were more likely to believe that all Americans enjoyed equal opportunity and that government support encouraged dependency, and they were more committed to materialist goals. In contrast, youth endorsing societal or situational causes had more altruistic life goals and reported that compassion was emphasized in their families.


Asunto(s)
Conducta del Adolescente/psicología , Actitud , Política , Autoimagen , Percepción Social , Adolescente , Familia/psicología , Femenino , Humanos , Masculino , Psicología del Adolescente , Encuestas y Cuestionarios
18.
J Fam Psychol ; 15(2): 254-71, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11458632

RESUMEN

This study examined the nature and extent of adolescent siblings' supportive roles and the conditions under which siblings provide support to one another about familial and nonfamilial issues. Data were collected from 185 adolescent firstborn (M age = 16 years) and second born (M age = 13 years) sibling pairs. In home interviews, siblings reported on family experiences and psychosocial functioning during the past year. In a series of 7 evening telephone interviews, siblings reported on their shared daily activities. Findings suggested that both older and younger siblings view older siblings as sources of support about nonfamilial issues such as social and scholastic activities and that siblings assume equally supportive roles about familial issues. Further, the results suggested that family background characteristics, sibling relationship qualities, and adolescents' psychosocial functioning were linked to the nature and extent of sibling support.


Asunto(s)
Relaciones Interpersonales , Relaciones entre Hermanos , Apoyo Social , Adolescente , Humanos
19.
Cad Saude Publica ; 17 Suppl: 133-40, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11426274

RESUMEN

All known Rift Valley fever(RVF) outbreaks in Kenya from 1950 to 1998 followed periods of abnormally high rainfall. On an interannual scale, periods of above normal rainfall in East Africa are associated with the warm phase of the El Niño/Southern Oscillation (ENSO) phenomenon. Anomalous rainfall floods mosquito-breeding habitats called dambos, which contain transovarially infected mosquito eggs. The eggs hatch Aedes mosquitoes that transmit the RVF virus preferentially to livestock and to humans as well. Analysis of historical data on RVF outbreaks and indicators of ENSO (including Pacific and Indian Ocean sea surface temperatures and the Southern Oscillation Index) indicates that more than three quarters of the RVF outbreaks have occurred during warm ENSO event periods. Mapping of ecological conditions using satellite normalized difference vegetation index (NDVI) data show that areas where outbreaks have occurred during the satellite recording period (1981-1998) show anomalous positive departures in vegetation greenness, an indicator of above-normal precipitation. This is particularly observed in arid areas of East Africa, which are predominantly impacted by this disease. These results indicate a close association between interannual climate variability and RVF outbreaks in Kenya.


Asunto(s)
Clima , Brotes de Enfermedades , Fiebre del Valle del Rift/epidemiología , Aedes , Animales , Bovinos , Reservorios de Enfermedades , Humanos , Insectos Vectores , Kenia/epidemiología , Lluvia , Fiebre del Valle del Rift/transmisión , Ovinos , Temperatura
20.
Proc Natl Acad Sci U S A ; 102(31): 10823-7, 2005 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-16043702

RESUMEN

An increase in photosynthetic activity of the northern hemisphere terrestrial vegetation, as derived from satellite observations, has been reported in previous studies. The amplitude of the seasonal cycle of the annually detrended atmospheric CO(2) in the northern hemisphere (an indicator of biospheric activity) also increased during that period. We found, by analyzing the annually detrended CO(2) record by season, that early summer (June) CO(2) concentrations indeed decreased from 1985 to 1991, and they have continued to decrease from 1994 up to 2002. This decrease indicates accelerating springtime net CO(2) uptake. However, the CO(2) minimum concentration in late summer (an indicator of net growing-season uptake) showed no positive trend since 1994, indicating that lower net CO(2) uptake during summer cancelled out the enhanced uptake during spring. Using a recent satellite normalized difference vegetation index data set and climate data, we show that this lower summer uptake is probably the result of hotter and drier summers in both mid and high latitudes, demonstrating that a warming climate does not necessarily lead to higher CO(2) growing-season uptake, even in high-latitude ecosystems that are considered to be temperature limited.


Asunto(s)
Dióxido de Carbono/metabolismo , Clima , Plantas/metabolismo , Efecto Invernadero , Fotosíntesis , Lluvia , Estaciones del Año , Temperatura
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