572 research outputs found
Effects of spatial variability and scale on areal -average evapotranspiration
This paper explores the effect of spatial variability and scale on areally-averaged evapotranspiration. A spatially-distributed water and energy balance model is employed to determine the effect of explicit patterns of model parameters and atmospheric forcing on modeled areally-averaged evapotranspiration over a range of increasing spatial scales. The analysis is performed from the local scale to the catchment scale. The study area is King's Creek catchment, an 11.7 sq km watershed located on the native tallgrass prairie of Kansas. The dominant controls on the scaling behavior of catchment-average evapotranspiration are investigated by simulation, as is the existence of a threshold scale for evapotranspiration modeling, with implications for explicit versus statistical representation of important process controls. It appears that some of our findings are fairly general, and will therefore provide a framework for understanding the scaling behavior of areally-averaged evapotranspiration at the catchment and larger scales
Evapotranspiration and runoff from large land areas: Land surface hydrology for atmospheric general circulation models
A land surface hydrology parameterization for use in atmospheric GCM's is presented. The parameterization incorporates subgrid scale variability in topography, soils, soil moisture and precipitation. The framework of the model is the statistical distribution of a topography-soils index, which controls the local water balance fluxes, and is therefore taken to represent the large land area. Spatially variable water balance fluxes are integrated with respect to the topography-soils index to yield our large topography-soils distribution, and interval responses are weighted by the probability of occurrence of the interval. Grid square averaged land surface fluxes result. The model functions independently as a macroscale water balance model. Runoff ratio and evapotranspiration efficiency parameterizations are derived and are shown to depend on the spatial variability of the above mentioned properties and processes, as well as the dynamics of land surface-atmosphere interactions
Arcanobacterium hemolyticum: identification and susceptibility to nine antimicrobial agents
AbstractObjective To evaluate the in vitro spectrum and activity of linezolid, a recent oxazolidinone, according to well-controlled surveillance data from 42 medical centers in 13 countries throughout Europe.Methods Participants tested the susceptibility of 125 clinical strains of enterococcal and staphylococcal species against 13 drugs using reference broth microdilution trays or the standardized disk diffusion method of the National Committee for Clinical Laboratory Standards (NCCLS). Streptococcal species (n = 25 at each center) were tested against six drugs using E test (AB BIODISK, Solna, Sweden). Quality assurance testing was conducted using NCCLS-recommended strains and verification of resistance to linezolid and other selected agents was performed by retesting strains at the regional (Europe) and international (USA) monitor sites.Results A total of 5598 strains from throughout Europe (91% compliance) were tested. Vancomycin resistance was reported in only 0.6 and 3.0% of Enterococcus faecalis and E. faecium, respectively. Penicillin resistance occurred in 25.1% of Streptococcus pneumoniae; 4.9% at the high-level (≥2 mg/L). The MIC90 for linezolid was 1 mg/L for streptococci and 2 mg/L for enterococci and staphylococci. Using the US FDA- and EUCAST-recommended susceptible breakpoints for linezolid, there were no confirmed reports of linezolid resistance [minimum inhibitory concentration (MIC), ≥8mg/L]. The distribution of linezolid MIC values was unimodal and varied between 0.25 and 1 mg/L for streptococci (≥90% of isolates), and between 1 and 2 mg/L for staphylococci (≥90%) and enterococci (≥95%). There were no differences in linezolid susceptibility in the vancomycin-, oxacillin-, or penicillin-resistant subsets of strains when compared to susceptible organism populations.Conclusions Compared to the North American component of this study, there was substantially less vancomycin resistance among E. faecium isolates (Europe 3.0% vs. North America 63.4%). While the occurrence of penicillin-resistant S. pneumoniae in Europe and North America was similar (25.1% vs. 29.7%), the recovery of high-level penicillin-resistant strains was nearly three-fold higher in North America (4.9% vs. 13.2%). Only linezolid was universally active against all the tested Gram-positive isolates at ≤4mg/L
Integrating Data from GRACE and Other Observing Systems for Hydrological Research and Applications
The Gravity Recovery and Climate Experiment (GRACE) mission provides a unique view of water cycle dynamics, enabling the only space based observations of water on and beneath the land surface that are not limited by depth. GRACE data are immediately useful for large scale applications such as ice sheet ablation monitoring, but they are even more valuable when combined with other types of observations, either directly or within a data assimilation system. Here we describe recent results of hydrological research and applications projects enabled by GRACE. These include the following: 1) global monitoring of interannual variability of terrestrial water storage and groundwater; 2) water balance estimates of evapotranspiration over several large river basins; 3) NASA's Energy and Water Cycle Study (NEWS) state of the global water budget project; 4) drought indicator products now being incorporated into the U.S. Drought Monitor; 5) GRACE data assimilation over several regions
A global near-real-time soil moisture index monitor for food security using integrated SMOS and SMAP
Soil Moisture (SM) is a direct measure of agricultural drought. While there are several global SM indices, none of them directly use SM observations in a near-real-time capacity and as an operational tool. This paper presents a near-real-time global SM index monitor based on integrated SMAP (Soil Moisture Active Passive) and SMOS (Soil Moisture and Ocean Salinity) remote sensing data. We make use of the short period (2015–2018) of SMAP datasets in combination with two approaches—Cumulative Distribution Function Mapping (CDFM) and Bayesian conditional process—and integrate them with SMOS data in a way that SMOS data is consistent with SMAP. The integrated SMOS and SMAP (SMOS/SMAP) has an increased global revisit frequency and a period of record from 2010 to the present. A four-parameter Beta distribution was fitted to the SMOS/SMAP dataset for each calendar month of each grid cell at ~36 km resolution for the period from 2010 to 2018. We used an asymptotic method that guarantees the values of the bounding parameters of the Beta distribution will envelop both the smallest and largest observed values. The Kolmogorov-Smirnov (KS) test showed that more grids globally will pass if the integrated dataset is from the Bayesian conditional approach. A daily global SM index map is generated and posted online based on translating each grid's integrated SM value for that day to a corresponding probability percentile relevant to the particular calendar month from 2010 to 2018. For validation, we use the Canadian Prairies Ecozone (CPE). We compare the integrated SM with the SMAP core validation and RISMA sites from ISMN, compare our indices with other models (VIC, ESA's CCI SM v04.4 integrated satellite data, and SPI-1), and make a two-by-two comparison of candidate indices using heat maps and summary CDF statistics. Furthermore, we visually compare our global SM-based index maps with those produced by other organizations. Our Global SM Index Monitor (GSMIM) performed, in many tests, similarly to the CCI's product SM index but with the advantage of being a near-real-time tool, which has applications for identifying evolving drought for food security conditions, insurance, policymaking, and crop planning especially for the remote parts of the globe
Improving Land-Surface Model Hydrology: Is an Explicit Aquifer Model Better than a Deeper Soil Profile?
Land surface models (LSMs) are computer programs, similar to weather and climate prediction models, which simulate the storage and movement of water (including soil moisture, snow, evaporation, and runoff) after it falls to the ground as precipitation. It is not currently possible to measure all of the variables of interest everywhere on Earth with sufficient accuracy. Hence LSMs have been developed to integrate the available information, including satellite observations, using powerful computers, in order to track water storage and redistribution. The maps are used to improve weather forecasts, support water resources and agricultural applications, and study the Earth's water cycle and climate variability. Recently, the models have begun to simulate groundwater storage. In this paper, we compare several possible approaches, and examine the pitfalls associated with trying to estimate aquifer parameters (such as porosity) that are required by the models. We find that explicit representation of groundwater, as opposed to the addition of deeper soil layers, considerably decreases the sensitivity of modeled terrestrial water storage to aquifer parameter choices. We also show that approximate knowledge of parameter values is not sufficient to guarantee realistic model performance: because interaction among parameters is significant, they must be prescribed as a harmonious set
Emerging Trends in Global Freshwater Availability
Freshwater availability is changing worldwide. Here we quantify 34 trends in terrestrial water storage (TWS) observed by the Gravity Recovery and Climate Experiment (GRACE) satellites during 2002-2016 and categorize their drivers as natural interannual variability, unsustainable groundwater consumption, or climate change. Several of these trends had been lacking thorough investigation and attribution, including massive changes in northwestern China and the Okavango delta. Others are consistent with climate model predictions. This observation-based assessment of how the world's water landscape is responding to human impacts and climate variations provides a blueprint for evaluating and predicting emerging threats to water and food security
Producción directa de aire caliente en colectores solares Fresnel para la industria minera: estudio de prefactibilidad
CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: Los colectores solares de concentración son una tecnologÃa adecuada para proporcionar calor a media temperatura. En este trabajo se presenta un diseño innovador para la generación solar directa de aire caliente para procesos térmicos industriales mediante colectores tipo Fresnel comerciales. El aire se utiliza como fluido caloportador, calentado dentro del receptor solar en configuración de circuito abierto, antes de ser entregado al usuario a 300/400 °C. Se utiliza un turbocompresor comercial de automoción para impulsar el aire a través del campo solar sin consumo de energÃa auxiliar de bombeo, gracias a un diseño en ciclo Brayton. Varios procesos industriales necesitan aire caliente por debajo de 400 °C, especialmente para el secado, común a diferentes sectores, incluida la minerÃa. En este trabajo se modela y simula una instalación solar a escala industrial, revelando la viabilidad de la propuesta.ABSTRACT: Concentrating solar collector are suitable technology for providing medium temperature heat. An innovative layout is presented in this work aiming at direct solar hot air generation for industrial thermal processes using commercial Linear Fresnel collectors. Air is used as heat transfer fluid, heated inside the solar receiver in an open circuit configuration before to be delivered to user at 300/400 °C. An automotive turbocharger is used to blow across the solar field avoiding auxiliary energy consumption for pumping, thanks to a Brayton cycle layout. Several industrial processes need hot air in the low and medium temperature range, below 400 °C, especially for drying, common to different sectors, including mining. An industrial-scale solar air heater is modeled and simulated in this work, revealing the feasibility of the proposed facility.info:eu-repo/semantics/publishedVersio
The Global Groundwater Crisis
Groundwater depletion the world over poses a far greater threat to global water security than is currently acknowledged
Correlation of physical and cognitive impairment in diabetic and hypertensive frail older adults
Background: Diabetes and hypertension are common in older adults and represent established risk factors for frailty. Frailty is a multidimensional condition due to reserve loss and susceptibility to stressors with a high risk of death, hospitalizations, functional and cognitive impairment. Comorbidities such as diabetes and hypertension play a key role in increasing the risk of mortality, hospitalization, and disability. Moreover, frail patients with diabetes and hypertension are known to have an increased risk of cognitive and physical impairment. Nevertheless, no study assessed the correlation between physical and cognitive impairment in frail older adults with diabetes and hypertension. Methods: We evaluated consecutive frail older patients with diabetes and hypertension who presented at ASL (local health unit of the Italian Ministry of Health) Avellino, Italy, from March 2021 to October 2021. The inclusion criteria were: a previous diagnosis of diabetes and hypertension with no evidence of secondary causes; age > 65 years; a frailty status; Montreal Cognitive Assessment (MoCA) score < 26. Results: 179 patients successfully completed the study. We found a strong and significant correlation between MoCA score and 5-m gait speed test (r: 0.877; p < 0.001). To further verify our results, we performed a linear multivariate analysis adjusting for potential confounding factors, with MoCA score as dependent variable, which confirmed the significant association with glycemia (p < 0.001). Conclusions: This is the first study showing a significant correlation between 5-m gait speed test and MoCA score in frail diabetic and hypertensive older adults
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