585 research outputs found
Electroencephalographic changes in albino rats subjected to stress
Twenty one albino Wistar rats were subjected to stress for 7 hours. There was a significant difference in the slopes of regression lines for 7 nonulcerous rats and those for 14 ulcerous rats. Nonulcerous rats subjected to stress showed greater EEG curve synchronization than did ulcerous rats. If curve synchronization can be equated to a relaxed state, it may therefore be possible to explain the protective action of hypnotics, tranquilizers and analgesics on ulcers
Climate, Not Conflict, Explains Extreme Middle East Dust Storm
The recent dust storm in the Middle East (September 2015) was publicized in the media as a sign of an impending ‘Dust Bowl.’ Its severity, demonstrated by extreme aerosol optical depth in the atmosphere in the 99th percentile compared to historical data, was attributed to the ongoing regional conflict. However, surface meteorological and remote sensing data, as well as regional climate model simulations, support an alternative hypothesis: the historically unprecedented aridity played a more prominent role, as evidenced by unusual climatic and meteorological conditions prior to and during the storm. Remotely sensed normalized difference vegetation index demonstrates that vegetation cover was high in 2015 relative to the prior drought and conflict periods, suggesting that agricultural activity was not diminished during that year, thus negating the media narrative. Instead, meteorological simulations using the Weather Research and Forecasting (WRF) model show that the storm was associated with a cyclone and ‘Shamal’ winds, typical for dust storm generation in this region, that were immediately followed by an unusual wind reversal at low levels that spread dust west to the Mediterranean Coast. These unusual meteorological conditions were aided by a significant reduction in the critical shear stress due to extreme dry and hot conditions, thereby enhancing dust availability for erosion during this storm. Concluding, unusual aridity, combined with unique synoptic weather patterns, enhanced dust emission and westward long-range transport across the region, thus generating the extreme storm
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Quand les ’candides’ evaluent les OGM... Nouveau modele de ’democratie technique’ ou mise en scence du debat public?
Residential density classification for sustainable housing development using a machine learning approach
Using Machine Learning (ML) algorithms for classification of the existing residential neighbourhoods and their spatial characteristics (e.g. density) so as to provide plausible scenarios for designing future sustainable housing is a novel application. Here we develop a methodology using a Random Forests algorithm (in combination with GIS spatial data processing) to detect and classify the residential neighbourhoods and their spatial characteristics within the region between Oxford and Cambridge, that is, the 'Oxford-Cambridge Arc'. The classification model is based on four pre-defined urban classes, that is, Centre, Urban, Suburban, and Rural for the entire region. The resolution is a grid of 500 m × 500 m. The features for classification include (1) dwelling geometric attributes (e.g. garden size, building footprint area, building perimeter), (2) street networks (e.g. street length, street density, street connectivity), (3) dwelling density (number of housing units per hectare), (4) building residential types (detached, semi-detached, terraced, and flats), and (5) characteristics of the surrounding neighbourhoods. The classification results, with overall average accuracy of 80% (accuracy per class: Centre: 38%, Urban 91%, Suburban 83%, and Rural 77%), for the Arc region show that the most important variables were three characteristics of the surrounding area: residential footprint area, dwelling density, and number of private gardens. The results of the classification are used to establish a baseline for the current status of the residential neighbourhoods in the Arc region. The results bring data-driven decision-making processes to the level of local authority and policy makers in order to support sustainable housing development at the regional scale
Soil seal development under simulated rainfall: structural, physical and hydrological dynamics
This study delivers new insights into rainfall-induced seal formation through a novel approach in the use of X-ray Computed Tomography (CT). Up to now seal and crust thickness have been directly quantified mainly through visual examination of sealed/crusted surfaces, and there has been no quantitative method to estimate this important property. X-ray CT images were quantitatively analysed to derive formal measures of seal and crust thickness. A factorial experiment was established in the laboratory using open-topped microcosms packed with soil. The factors investigated were soil type (three soils: silty clay loam - ZCL, sandy silt loam - SZL, sandy loam - SL) and rainfall duration (2-14 minutes). Surface seal formation was induced by applying artificial rainfall events, characterised by variable duration, but constant kinetic energy, intensity, and raindrop size distribution. Soil porosities derived from CT scans were used to quantify the thickness of the rainfall-induced surface seals and reveal temporal seal micro-morphological variations with increasing rainfall duration. In addition, the water repellency and infiltration dynamics of the developing seals were investigated by measuring water drop penetration time (WDPT) and unsaturated hydraulic conductivity (Kun). The range of seal thicknesses detected varied from 0.6 - 5.4 mm. Soil textural characteristics and OM content played a central role in the development of rainfall-induced seals, with coarser soil particles and lower OM content resulting in thicker seals. Two different trends in soil porosity vs. depth were identified: i) for SL soil porosity was lowest at the immediate soil surface, it then increased constantly with depth till the median porosity of undisturbed soil was equalled; ii) for ZCL and SL the highest reduction in porosity, as compared to the median porosity of undisturbed soil, was observed in a well-defined zone of maximum porosity reduction c. 0.24 - 0.48 mm below the soil surface. This contrasting behaviour was related to different dynamics and processes of seal formation which depended on the soil properties. The impact of rainfall-induced surface sealing on the hydrological behaviour of soil (as represented by WDTP and Kun) was rapid and substantial: an average 60% reduction in Kun occurred for all soils between 2 and 9 minutes rainfall, and water repellent surfaces were identified for SZL and ZCL. This highlights that the condition of the immediate surface of agricultural soils involving rainfall-induced structural seals has a strong impact in the overall ability of soil to function as water reservoir
Combined paclitaxel and gemcitabine as first-line treatment in metastatic non-small cell lung cancer: a multicentre phase II study
The efficacy and toxicity of combined paclitaxel and gemcitabine was evaluated in 54 chemotherapy-naive patients with metastatic non-small cell lung cancer (NSCLC). Gemcitabine i.v. 1000 mg/m2was administered on days 1 and 8 and paclitaxel 200 mg/m2as a continuous 3-hour infusion on day 1. Treatment was repeated every 21 days. Patients had a median age of 53 years. ECOG performance status was 0 or 1 in 48 patients. 41 patients (75.9%) had initial stage IV disease; histology was mainly adenocarcinoma (46.3%). 2 patients (4.3%) achieved a complete response and 15 (31.9%) achieved a partial response giving an overall response rate of 36.2% (95% CI: 22.4–49.9%); 19 patients (40.4%) had stable disease and 10 (21.3%) had progressive disease. The median survival time was 51 weeks (95% CI: 46.5–59.3), with a 1-year survival probability of 0.48 (95% CI: 0.34–0.63). Grade 3/4 neutropenia and febrile neutropenia occurred in 15.2% and 2.2% of courses, respectively. Grade 3/4 thrombocytopenia was rare (1.8% of courses). Peripheral neurotoxicity developed in 25 patients (47.2%), mostly grade 1/2. Arthalgia/myalgia was observed in 30 patients (56.6%), generally grade 1 or 2. Grade 3 abnormal levels of serum glutamate pyruvate transaminase (SGPT) and serum glutamate oxaloacetate transaminase (SGOT) occurred in 5 patients (9.4%) and 1 patient (1.9%), respectively. Combined paclitaxel and gemcitabine is an active and well-tolerated regimen for the treatment of advanced NSCLC, and warrants further investigation in comparative, randomized trials. © 2001 Cancer Research Campaign http://www.bjcancer.co
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A simple accurate method to predict time of ponding under variable intensity rainfall
The prediction of the time to ponding following commencement of rainfall is fundamental to hydrologic prediction of flood, erosion, and infiltration. Most of the studies to date have focused on prediction of ponding resulting from simple rainfall patterns. This approach was suitable to rainfall reported as average values over intervals of up to a day but does not take advantage of knowledge of the complex patterns of actual rainfall now commonly recorded electronically. A straightforward approach to include the instantaneous rainfall record in the prediction of ponding time and excess rainfall using only the infiltration capacity curve is presented. This method is tested against a numerical solution of the Richards equation on the basis of an actual rainfall record. The predicted time to ponding showed mean error ≤7% for a broad range of soils, with and without surface sealing. In contrast, the standard predictions had average errors of 87%, and worst-case errors exceeding a factor of 10. In addition to errors intrinsic in the modeling framework itself, errors that arise from averaging actual rainfall records over reporting intervals were evaluated. Averaging actual rainfall records observed in Israel over periods of as little as 5 min significantly reduced predicted runoff (75% for the sealed sandy loam and 46% for the silty clay loam), while hourly averaging gave complete lack of prediction of ponding in some of the cases.Keywords: Infiltration, Variable rainfall, Pondering, Runof
A constant and similar assembly defect of mitochondrial respiratory chain complex I allows rapid identification of NDUFS4 mutations in patients with Leigh syndrome
AbstractIsolated complex I deficiency is a frequent cause of respiratory chain defects in childhood. In this study, we report our systematic approach with blue native PAGE (BN-PAGE) to study mitochondrial respiratory chain assembly in skin fibroblasts from patients with Leigh syndrome and CI deficiency. We describe five new NDUFS4 patients with a similar and constant abnormal BN-PAGE profile and present a meta-analysis of the literature. All NDUFS4 mutations that have been tested with BN-PAGE result in a constant and similar abnormal assembly profile with a complete loss of the fully assembled complex I usually due to a truncated protein and the loss of its canonical cAMP dependent protein kinase phosphorylation consensus site. We also report the association of abnormal brain MRI images with this characteristic BN-PAGE profile as the hallmarks of NDUFS4 mutations and the first founder NDUFS4 mutations in the North-African population
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