90 research outputs found
Study of water pollution by agricultural inputs: case of five intensive agriculture areas in Burkina Faso
Pour optimiser les rendements (agricoles), l’agriculture intensive nécessite une utilisation massive d’intrants agricoles dont les engrais chimiques, potentiellement sources de pollution des ressources en eau.
La région du Sud - Ouest du Burkina, dont font partie les zones concernées par la présente étude, connaît une agriculture intensive du coton. Il est fait usage dans les champs de coton, d’engrais à base essentiellement d’azote, de phosphate, de potassium, mais également d’urée, de chlorure de potassium et de nitrate d’ammonium. Un total de 42 échantillons d’eau de surface, de puits et de forages ont fait l’objet d’analyses, afin d’évaluer l’impact de ces engrais sur la qualité des ressources en eau de consommation des populations sur une année. Eu égard à la nature des fertilisants utilisés, les paramètres essentiels suivants ont été ciblés : Nitrates, nitrites, ortho-phosphates, ammonium, potassium, conductivité électrique et dureté totale.
Il ressort de ces investigations que les eaux de puits, pendant la saison hivernale, présentent des teneurs plus importantes en nitrates et potassium avec des valeurs maximales respectives de 178 mg/L (plus de 3 fois la valeur limite admise par l’OMS pour les eaux de consommation) et 55 mg/L pour une norme admise par l’OMS de 10 mg/L en potassium. Les ortho-phosphates, forme soluble du phosphore et les nitrites, présentent des teneurs inférieures aux normes admises. S’agissant des ions ammonium, un seul puits par sa position en aval d’un WC et d’un parc d’animaux, a donné des valeurs supérieures à la norme qui est fixée à 1,5 mg/L, atteignant ainsi 20 mg/L de N-NH+4. Les échantillons d’eau de forages sont exempts de toute contamination, alors que 33% des prélèvements d’eau de surface ont donné des teneurs dépassant la valeur limite admise seulement en potassium. Globalement, 61% des échantillons d’eau de puits sont contaminés par les nitrates, 67% par le potassium et 17% donnent des teneurs supérieures à la norme en ammonium. Ce qui permet d’en déduire qu’il y a une infiltration de pollution dans la nappe superficielle qui alimente les puits. La conductivité électrique et la dureté totale sans être excessives présentent les valeurs les plus importantes pour les mêmes sites que sont les puits, avec des valeurs maximales respectives
de 1252 μS/cm et 202 mg/L de CaCO3
Phenotypic characterisation and molecular polymorphism of indigenous poultry populations of the species Gallus gallus of Savannah and Forest ecotypes of Benin
The study of the phenotypic characterisation and molecular polymorphism of local chicken populations was carried out in Benin on 326 chickens of the Forest ecological area and 316 of the Savannah ecological area, all were 7 months old at least. The collection of blood for the molecular typing wasachieved on 121 indigenous chickens of which 60 from the Savannah ecological area and 61 from the Forest ecological area. The genotyping was carried out for 22 microsatellite loci. Weight and body measures of the Savannah chickens were significantly higher (P < 0.001) than those of the Forest chickens. In the Savannah ecological area, the most frequent plumage colours were the black (22.15%), the white (19.62%), the coppery black (7.59%) and the golden partridge (7.59%). In the Forest area, thefawn (15.34%), the black (10.43%), the white (6.8%), the silver white (6.8%) and the golden partridge (6.75%) were the dominant feather colours. Thus, phenotypic characterisation showed significant differences between Savannah and Forest local chickens. The FST calculated between the Savannah and Forest populations revealed a low genetic differentiation and the dendogram showed that Savannah and Forest chickens were quite intermingled. In conclusion, local populations from Savannah andForest area may be considered as ecotypes, but not as two distinct breeds
Stress echocardiography in elderly patients with coronary artery disease Applicability, safety and prognostic value of dobutamine and adenosine echocardiography in elderly patients
AbstractObjectives. Our aim was to determine the applicability, safety and prognostic value of adenosine and dobutamine stress echocardiography in patients ≥70 years old.Background. These tests are sometimes mandatory because of difficulties and inaccuracies in interpreting traditional electrocardiographic stress tests. Furthermore, if these tests could be used to avoid coronary arteriography and cardiac catheterization, they would become essential in the care of the elderly, whose numbers are increasing.Methods. We performed coronary arteriography and dobutamine and adenosine stress echocardiographic tests in 120 patients (72 men) ≥70 years old who entered the hospital because of chest pain and had known or suspected coronary artery disease. The stress tests were performed on separate days, within 2 weeks of coronary arteriography. Both the arteriograms and the echocardiograms were analyzed by two experts who had no knowledge of the patients' other data or the other interpreter's report. Tests were judged to have positive or negative results, and the patients were followed up for the development of cardiac events. Univariate and multivariate analyses and other statistical modalities were applied for comparisons.Results. Documented coronary artery disease was found in 89 patients. During the 14 ± 7 months of follow-up, cardiac events developed in 50 patients, including 3 (7.9%) of 38 patients with negative dobutamine and 12 (20.7%) of 58 patients with negative adenosine test results. Demonstration of any abnormality on stress echocardiography was an independent factor for cardiac events, both for dobutamine (relative risk 7.3) and for adenosine (relative risk 3.0). Both cessation of dobutamine or adenosine tests and diagnosis of disease in two or more coronary vessels were also independent predictors. ST segment depression ≥1 mm was related to future events only with the dobutamine test.Conclusions. These echocardiographic stress tests proved safe and well tolerated. They successfully stratified this cohort of elderly patients with coronary artery disease to low or high risk subgroups for subsequent cardiac events
Mixing and Circulation in the Tropical Atlantic Cruise No. M98
July 01 – July 28, 2013
Fortaleza (Brazil) – Walvis Bay (Namibia
A multi-decade record of high quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)
The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO2 values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO2 values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO2 has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) “living data” publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014). Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi:10.3334/CDIAC/OTG.SOCAT_V3_GRID
Photosynthetic pigments and quantum yield of West Indian cherry under salt stress and NPK combinations
Abstract West Indian cherry cultivation has proved to be an important economic activity in northeastern Brazil. However, irrigation with brackish waters limits cultivation, requiring new strategies to minimize the effect of salt stress. In this context, the present study aimed to evaluate the effect of nitrogen (N), phosphorus (P), and potassium (K) combinations on the photosynthetic pigments and quantum yield of West Indian cherry cultivated under salt stress, in the second year of production. The assay was conducted in a protected environment by adopting an experimental design in randomized blocks, with treatments distributed in a 2×10 factorial arrangement referring to two electrical conductivity levels of irrigation water - ECw (0.6 and 4.0 dS m-1) and 10 NPK fertilization combinations - FC (80-100-100; 100-100-100; 120-100-100; 140-100-100; 100-80-100; 100-120-100; 100-140-100; 100-100-80; 100-100-120, and 100-100-140% of the recommendation, in the second year of production), with three replications, each consisting of one plant. Irrigation with the electrical conductivity of 4.0 dS m-1 negatively affected the synthesis of photosynthetic pigments and the photochemical efficiency of the West Indian cherry cv. Flor Branca. The NPK combinations did not attenuate the effects of salt stress on the analyzed variables. However, the combinations referring to 120-100-100%, 140-100-100%, and 100-120-100% of NPK recommendation improved the quantum yield of photosystem II by reducing the initial fluorescence and increasing the maximum fluorescence of the West Indian cherry cv. Flor Branca
Potential clinical applications of myocardial contrast echocardiography in evaluating myocardial perfusion in coronary artery disease
Myocardial contrast echocardiography (MCE) is a relatively new technique
that uses microbubbles to produce myocardial opacification. Recent
advances in echocardiography have resulted in improved detection of
microbubbles within the myocardium allowing combined acquisition of
function and perfusion data, thus making MCE suitable for bedside use.
Regardless of the imaging modality chosen or the type of stress used,
MCE detects changes developing in the coronary microcirculation,
providing important information for the evaluation of severity of
coronary artery disease and for the detection of viable myocardial
tissue in acute or chronic coronary artery disease. (c) 2005 Elsevier
Ireland Ltd. All rights reserved
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