1,157 research outputs found
Use of textile waste as an addition in the elaboration of an ecological concrete block
The textile industry has grown significantly in recent years, reaching a global fiber production of 53 million tons which 12 % are recycled; Construction sector has been using more and more recycled materials from different industrial sources, to apply them in their constructions and to reduce CO2 emissions and final energy consumption. The present study aims to study the behavior of concrete blocks of fÄ= 210 kg/cm2 adding polyester textile waste with 3 %, 6 %, 9 %, 12 % and 15 %; void content, compressive strength and thermal conductivity decrease, and water absorption, acoustic insulation and unit price increase by 3 %, 34 % and 16 % compared to conventional concrete block
Tectonic and climatic controls on the Chuquibamba landslide (western Andes, southern Peru)
The contribution of landslides to the Quaternary evolution of relief is poorly documented in arid contexts. In southern Peru and northern Chile, several massive landslides disrupt the arid western Andean front. The Chuquibamba landslide, located in southern Peru, belongs to this set of large landslides. In this area, the Incapuquio fault system captures the intermittent drainage network and localizes rotational landslides. Seismic activity is significant in this region with recurrent Mw9 subduction earthquakes; however, none of the latest seismic events have triggered a major landslide. New terrestrial cosmogenic dating of the Chuquibamba landslide provides evidence that the last major gravitational mobilization of these rotational landslide deposits occurred at ~ 102 ka, during the Ouki wet climatic event identified on the Altiplano between 120 and 98 ka. Our results suggest that wet events in the arid and fractured context of the Andean forearc induced these giant debris flows. Finally, our study highlights the role of tectonics and climate on (i) the localization of large Andean landslides in the Western Cordillera and on (ii) the long-term mass transfer to the trench along the arid Andean front
Transport of NaNO 3 solutions across an activated composite membrane: electrochemical and chemical surface characterizations
Abstract Electrochemical characterization of two different samples of an activated membrane, which consists of a polymeric support containing different amounts of Di-(2-ethylhexyl) phosphoric acid as a carrier, was made by measuring the electrical resistance, salt diffusion and membrane potential for the activated membranes and the polymeric support in contact with NaNO 3 solutions. Transport parameters such as the ion transport numbers and concentration of Âźxed charge in the membrane, salt and ionic permeabilities at different NaNO 3 concentrations were obtained. A comparison of the different electrochemical parameters obtained with both activated membranes and the polymeric support shows how the carrier affects the transport of NaNO 3 solutions across the activated membranes. On the other hand, chemical composition of the membrane surfaces as a function of the amount of carrier was determined by X-ray photoelectron spectroscopy technique, which also allows an envisagement of the chemical bonding between the carrier and the membrane top layer (polyamide).
The Differentiation and Promotion of Studentsâ Rights in Portugal
This investigation includes a differential study (Study 1)
and a quasi-experimental research (Study 2). In Study 1, the objective
was to establish to what extent studentsâ rights existed and analyse
the differentiation between studentsâ rights with Portuguese and
immigrant mothers, throughout school years. The sample consisted of
537 students with Portuguese and immigrant mothers, distributed by
different school years (7th, 9th and 11th grades). The Childrenâs Rights
Scale (Hart et al., 1996; Veiga, 2001) was used. In Study 2, the purpose
was to analyse the effects on studentsâ rights of the use by teachers of a
communicational intervention program, supervised by school psychologists.
The sample involved 7th and 9th grade students, in a total of
four classes, two forming the experimental groups (n = 36) and two the
control groups (n = 43); as in Study 1, the Childrenâs Rights Scale was used. The results indicated the effectiveness of the communicational intervention program on studentsâ rights and are consistent with previous studies. An implication is that psychologists and teachers, working together and taking a human rights perspective, may develop an important role in projects to promote the studentsâ rights
Implicaciones del funcionamiento de un acuĂfero carbonatado fisurado complejo (Sierra de Lujar, Granada) en la variabilidad hidroquĂmica de su descarga natural
A hydrochemical study was carried out in a triassic carbonate aquifer located in a coastal mountain chain in the southern part of the Granada province (Sierra de LĂșjar, AlpujĂĄrride Complex, Betic Cordillera). This aquifer is made up of limestones and dolomites with marly and/or pelitic intercalations and sorne gypsum scattered or interbedded. Though the area is semid-arid, recharge by precipitation -rain or snow melt- is relatively high (over 600 mm/year) because of its mountainous nature up to near 1.900 m. The recharge of the aquifer also comes from the Guadalfeo river which crosses the permeable outcrops losing part of its stream flow. The carbonate rocks present dense microfissuration; the ground water regime is predominantly diffuse. The karstic forms are, in general, poorly developed either in the surface or at the level of speleological networks in the carbonate material. These characteristics influence the ground water chemistry, so the variability of physical-chemical parameters of water is very low, with single shaped histograms of these parameters. Although, in sorne points a larger variability was found related to mixing with streamwaters from the Guadalfeo river.Se ha llevado a cabo un estudio hidroquĂmico en un acuĂfero carbonatado triĂĄsico localizado en una cadena montañosa costera en el Sur de la provincia de Granada (Sierra de LĂșjar, Complejo AlpujĂĄrride, Cordillera BĂ©tica). Este acuĂfero estĂĄ constituido por calizas y dolomĂas con intercalaciones margosas y/o pelĂticas y yeso diseminado. Aunque el ĂĄrea es semiĂĄrida, la recarga por la precipitaciĂłn (bien por la lluvia o por el agua de fusiĂłn niva!) es relativamente elevada (superior a 600 mm/año) debido a su naturaleza montañosa, cercana a los 1.900 m s.n.m. AdemĂĄs, el rĂo Guadalfeo recarga al acuĂfero al perder parte de su caudal cuando atraviesa los afloramientos permeables. Las rocas carbonatadas presentan una densa microfisuraciĂłn; el rĂ©gimen de flujo es predominantemente difuso. Las formas kĂĄrsticas estĂĄn, por lo general, poco desarrolladas tanto en superficie como a nivel de redes espeleolĂłgicas. Estas caracterĂsticas influyen en la quĂmica del agua subterrĂĄnea, por lo que la variabilidad de los diferentes parĂĄmetros fĂsicoquĂmicos del agua es reducida, con grĂĄficos de distribuciĂłn de frecuencias de dichos parĂĄmetros de formas, generalmente, unimodales. Sin embargo, se ha encontrado una mayor variabilidad en aquellos puntos en los que existe mezcla con aguas superficiales procedentes del rĂo Guadalfeo
Experimental results and modelling of humidity control strategies for greenhouses in continental and coastal settings in the Mediterranean region. II: Modelling of strategies
Strategies for humidity control âwith and without heatingâ were evaluated via simulations performed with apreviously developed model (see accompanying paper, this issue, part I). With heating, the best strategy combined theuse of a humidity setpoint with step control of the roof window, increasing the ventilation in line with the outsidetemperature. Without heating, the best strategy again combined the use of a humidity setpoint with step control of theroof window, but required ventilation to be increased in line with the inside air temperatur
Discordant bioinformatic predictions of antimicrobial resistance from whole-genome sequencing data of bacterial isolates: an inter-laboratory study.
Antimicrobial resistance (AMR) poses a threat to public health. Clinical microbiology laboratories typically rely on culturing bacteria for antimicrobial-susceptibility testing (AST). As the implementation costs and technical barriers fall, whole-genome sequencing (WGS) has emerged as a 'one-stop' test for epidemiological and predictive AST results. Few published comparisons exist for the myriad analytical pipelines used for predicting AMR. To address this, we performed an inter-laboratory study providing sets of participating researchers with identical short-read WGS data from clinical isolates, allowing us to assess the reproducibility of the bioinformatic prediction of AMR between participants, and identify problem cases and factors that lead to discordant results. We produced ten WGS datasets of varying quality from cultured carbapenem-resistant organisms obtained from clinical samples sequenced on either an Illumina NextSeq or HiSeq instrument. Nine participating teams ('participants') were provided these sequence data without any other contextual information. Each participant used their choice of pipeline to determine the species, the presence of resistance-associated genes, and to predict susceptibility or resistance to amikacin, gentamicin, ciprofloxacin and cefotaxime. We found participants predicted different numbers of AMR-associated genes and different gene variants from the same clinical samples. The quality of the sequence data, choice of bioinformatic pipeline and interpretation of the results all contributed to discordance between participants. Although much of the inaccurate gene variant annotation did not affect genotypic resistance predictions, we observed low specificity when compared to phenotypic AST results, but this improved in samples with higher read depths. Had the results been used to predict AST and guide treatment, a different antibiotic would have been recommended for each isolate by at least one participant. These challenges, at the final analytical stage of using WGS to predict AMR, suggest the need for refinements when using this technology in clinical settings. Comprehensive public resistance sequence databases, full recommendations on sequence data quality and standardization in the comparisons between genotype and resistance phenotypes will all play a fundamental role in the successful implementation of AST prediction using WGS in clinical microbiology laboratories
Decay of building materials in the Circular Mausoleum Necopolis of Carmona, Spain
1 page. Benavente, David et al.-- ComunicaciĂłn presentada al International Congress on Science and Technology for the Conservation of Cultural Heritage Santiago de Compostela, Spain, 2-5 October 2012.Peer reviewe
Atrial fibrillation in a primary care practice: prevalence and management
BACKGROUND: Atrial fibrillation is a common serious cardiac arrhythmia. Knowing the prevalence of atrial fibrillation and documentation of medical management are important in the provision of primary care. This study sought to determine the prevalence of atrial fibrillation in a primary care population and to identify and quantify the treatments being used for stroke prevention in this group of patients. METHODS: A prevalence study through chart audit was conducted in the family medicine practice at the Sunnybrook campus of the Sunnybrook and Women's College Health Sciences Centre. The main outcome measures were the prevalence of atrial fibrillation in our primary care practice and the use of warfarin for stroke prevention in this population. RESULTS: 261 patients in our practice have atrial fibrillation. The overall prevalence in our family practice unit is 3.9%. When considering patients aged 60 and over, the prevalence rises to 12.2%. 204 of our patients with atrial fibrillation (78.2%) are currently being treated with warfarin. Another 21 patients were previously treated and discontinued for a number of reasons. Of the 57 patients not currently treated with warfarin, 44 are treated with ASA, 2 with ticlopidine, and 11 are receiving no preventative treatment. CONCLUSIONS: The prevalence of atrial fibrillation in our practice is higher than the range of prevalence reported in the general literature. However, our coverage with warfarin treatment exceeds previous reports in the literature
Carotid endarterectomy - An evidence-based review: Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology
Objective: To assess the efficacy of carotid endarterectomy for stroke prevention in asymptomatic and symptomatic patients with internal carotid artery stenosis. Additional clinical scenarios, such as use of endarterectomy combined with cardiac surgery, are also reviewed. Methods: The authors selected nine important clinical questions. A systematic search was performed for articles from 1990 (the year of the last statement) until 2001. Additional articles from 2002 through 2004 were included using prespecified criteria. Two reviewers also screened for other relevant articles from 2002 to 2004. Case reports, review articles, technical studies, and single surgeon case series were excluded. Results: For several questions, high quality randomized clinical trials had been completed. Carotid endarterectomy reduces the stroke risk compared to medical therapy alone for patients with 70 to 99% symptomatic stenosis (16% absolute risk reduction at 5 years). There is a smaller benefit for patients with 50 to 69% symptomatic stenosis (absolute risk reduction 4.6% at 5 years). There is a small benefit for asymptomatic patients with 60 to 99% stenosis if the perioperative complication rate is low. Aspirin in a dose of 81 to 325 mg per day is preferred vs higher doses (650 to 1,300 mg per day) in patients undergoing endarterectomy. Conclusions: Evidence supports carotid endarterectomy for severe (70 to 99%) symptomatic stenosis (Level A). Endarterectomy is moderately useful for symptomatic patients with 50 to 69% stenosis (Level B) and not indicated for symptomatic patients with \u3c50% stenosis (Level A). For asymptomatic patients with 60 to 99% stenosis, the benefit/risk ratio is smaller compared to symptomatic patients and individual decisions must be made. Endarterectomy can reduce the future stroke rate if the perioperative stroke/death rate is kept low (\u3c3%) (Level A). Low dose aspirin (81 to 325 mg) is preferred for patients before and after carotid endarterectomy to reduce the rate of stroke, myocardial infarction, and death (Level A). Copyright © 2005 by AAN Enterprises, Inc
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