80 research outputs found
Influence of solar activity on hydrological processes
International audienceThe relationship between solar activity and the water volumes of lakes is searched here by means of correlational and spectral analysis methods. The level of two lakes, Pátzcuaro in México and Tchudskoye in Russia, together with solar activity indexes are used for the analysis. It is found that the source of the oscillation mechanism of the level of those lakes is the solar activity cycle through its influence on the magnetosphere and the terrestrial atmosphere. The present study allows for the development of long-period prognostic of water volumes of big lakes
Spectral Optical Properties of the Polluted Atmosphere of Mexico City (Spring-Summer 1992)
A joint Mexican, Russian, and American research effort has been initiated to develop new methods to remotely sense atmospheric parameters using ground-based, aircraft, and satellite observations. As a first step in this program, ground-based spectrophotometric measurements of the direct solar radiation have been obtained for the extremely polluted Mexico City atmosphere for the period of April-June 1992. These observations were made at more than 1300 channels in the spectral range of 0.35-0.95 microns. In the UltraViolet (UV) portions of the spectrum (e.g., 0.35 microns), aerosol optical thicknesses were found to range between 0.6 and 1.2; in the visible portion of the spectrum (e. g., 0.5 microns) they ranged from 0.5 to 0.8; and in the Near-Infrared (NIR) spectra (e.g., 0.85 micron), values of 0.3 - 0.5 were found. Applying a Spectral Optical Depth (SOD) model of tau(lambda) = C + A(lambda(sup -varies as), values of 1.55 less than varies as less than 1.85 were obtained for polluted, cloudless days, with values of 1.25 less than varies as less than 1.60 on days with haze. The aerosol particles in the polluted Mexico City atmosphere were found to be strongly absorbing, with a single-scattering albedo of 0.7 - 0.9 in the UV, 0.6 - 0.8 in the visible portion of the spectrum, and 0.4 - 0.7 in the NIR. These values are possibly consistent with a high soot concentration, contributed both by vehicular traffic and heavy industry. Analysis of the measured aerosol SOD using the optical parameters of an urban aerosol model pemiits the concentration of aerosol particles to be estimated in the vertical column; a maximum value of 3 x 10(exp 9) 1/sq cm was found. This concentration of aerosol particles exceeds that found in most other regions of the globe by at least an order of magnitude. Near the ground the aerosol size distributions measured using an optical particle counter were found to be strongly multimodal
HELMINTHIASIS IN ALPACAS (Vicugna pacos) OF TWO PEASANT COMMUNITIES IN MACUSANI, PUNO DURINGTHE DRY SEASON
alpacas de dos comunidades del distrito de Macusani, Puno, durante la época de seca y las asociaciones con las variables edad y procedencia; así como establecer el promedio de carga parasitaria e identificar los géneros de helmintos presentes. Se colectaron muestras de heces de 1319 alpacas durante agosto a octubre de 2010 y se procesaron con las técnicas de flotación con solución Willis y sedimentación espontánea. Para la estimación de la carga e identificación de larvas de nematodos se utilizó el método McMaster modificado y Baermann, respectivamente. La prevalencia de helmintos fue de 63.9 ± 2.6%. En la prueba de regresión logística se determinó que la edad constituyó un factor de riesgo para la presencia de helmintos (p<0.05), donde alpacas de 5 meses a <1 año y aquellas de 1 a 3 años de edad presentaron 2.93 y 1.98 veces mayor riesgo de presentar esta parasitosis que animales >3 años; en tanto que no hubo diferencias en prevalencias entre las dos comunidades. La carga parasitaria por cada género de nematodo no superó los 100 hpg. Los helmintos identificados fueron Nematodirus, Trichuris, Moniezia, Cooperia, Oesophagostomum, Trichostrongylus, Ostertagia, Bunostomum, Haemonchus, Capillaria y Lamanema, donde Nematodirus spp presentó una prevalencia del 52.8%, seguido de Trichuris spp (10.8%) y Moniezia spp (9.6%).The study aimed to estimate the prevalence of gastrointestinal helminth in alpacas oftwo peasant communities in Macusani district, Puno, Peru during the dry season and itsassociation with age and origin; also, to establish the average parasite burden and to identify the genus of helminth presents. Stool samples were collected from 1319 alpacasfrom August to October 2010 and were processed by the flotation method using Willissolution and by the spontaneous sedimentation technique. The parasite burden andidentification of nematode larvae was done by the McMaster method and the modifiedBaermann technique respectively. The prevalence of helminths was 63.9 ± 2.6%. Thelogistic regression test showed that age was a risk factor for the presence of helminths(p3 years old, while there wasno difference in the prevalence between the two communities. The parasite burden pereach genus was lower than 100 epg. Helminth genus identified were Nematodirus,Trichuris, Moniezia, Cooperia, Oesophagostomum, Trichostrongylus, Ostertagia,Bunostomum, Haemonchus, Capillaria and Lamanema, where the prevalence ofNematodirus spp was the highest (52.8%) followed by Trichuris spp (10.8%) and Monieziaspp (9.6%)
Pleasure, Health and Sociability. Food Fact and Food Choice through Iberian Ham
A medida que avanzan los estudios sobre el polisémico ámbito de la alimentación humana,
resulta más necesario considerar mayor número de variables para analizar con solvencia el hecho
alimentario. Más allá de los estudios sobre las fases de producción y distribución, nuestra propuesta
se centra en la fase del consumo y trata de identificar los elementos que explican por qué las
sociedades seleccionan y prefieren unos alimentos en detrimento de otros. Actualmente, la selección
alimentaria está intrínsecamente presente en el hecho alimentario de las sociedades modernas,
relegando a un segundo plano los factores biológicos y fisiológicos, en relación a parámetros
dominantes comparados con el placer, la salud y la sociabilidad. Mediante una combinación de
técnicas cuantitativas y cualitativas, este estudio propone la relevancia de dimensiones como el
placer y la salud como elementos que guían a los consumidores para elegir un determinado
producto gourmet, como es el caso del jamón ibérico en España.Esta investigación es el resultado del proyecto I+D (CSO2013-42468-P) del Ministerio de Economía
y Competitividad Las marcas de calidad en el mundo rural: nuevos retos para productores
y consumidores
Mapping Health Literacy Research in the European Union: A Bibliometric Analysis
Background: To examine and compare the research productivity on selected fields related to health literacy of the curren
A novel thymidylate synthase from the Vibrionales, Alteromonadales, Aeromonadales, and Pasteurellales (VAAP) clade with altered nucleotide and folate binding sites
Thymidylate synthase (TS, E.C. 2.1.1.45) is a crucial enzyme for de novo deoxythymidine monophosphate (dTMP) biosynthesis. The gene for this enzyme is thyA, which encodes the folate-dependent TS that converts deoxyuridine monophosphate group (dUMP) into (dTMP) using the cofactor 5,10-methylenetetrahydrofolate (mTHF) as a carbon donor. We identified the thyA gene in the genome of the Vibrio parahaemolyticus strain FIM-S1708+ that is innocuous to humans but pathogenic to crustaceans. Surprisingly, we found changes in the residues that bind the substrate dUMP and mTHF, previously postulated as invariant among all TSs known (Finer-Moore, Santi & Stroud, 2003). Interestingly, those amino acid changes were also found in a clade of microorganisms that contains Vibrionales, Alteromonadales, Aeromonadales, and Pasteurellales (VAAP) from the Gammaproteobacteria class. In this work, we studied the biochemical properties of recombinant TS from V. parahemolyticus FIM-S1708+ (VpTS) to address the natural changes in the TS amino acid sequence of the VAAP clade. Interestingly, the Km for dUMP was 27.3 ± 4.3 µM, about one-fold larger compared to other TSs. The Km for mTHF was 96.3 ± 18 µM, about three- to five-fold larger compared to other species, suggesting also loss of affinity. Thus, the catalytic efficiency was between one or two orders of magnitude smaller for both substrates. We used trimethoprim, a common antibiotic that targets both TS and DHFR for inhibition studies. The IC50 values obtained were high compared to other results in the literature. Nonetheless, this molecule could be a lead for the design antibiotics towards pathogens from the VAAP clade. Overall, the experimental results also suggest that in the VAAP clade the nucleotide salvage pathway is important and should be investigated, since the de novo dTMP synthesis appears to be compromised by a less efficient thymidylate synthase
Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).
Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
Correlation analysis technique revealing ionospheric precursors of earthquakes
International audienceIn this paper we focus on the variability of electron concentration in the ionosphere measured by ground based ionosondes and GPS receivers around the time of strong earthquakes. It has been detected and statistically proven that several days before the seismic shock the level of this variability increases at the station closest to the epicenter, a fact which can be regarded as precursory phenomenon. More precisely the localness of this specific kind of ionospheric variability is used for the correlation analysis of data of several observation points. The similarity of geographical location of the observation points leads to the similarity of ionospheric variations registered at these sites during both quiet and disturbed geomagnetic conditions, except in the case of those located at the seismoactive zone. As a rule, the local anomalies in the F2 layer and TEC accompanying the preparation of strong earthquakes show themselves in the breaking of the mutual correlation of the critical frequencies foF2 or TEC between stations situated in and outside the seismic zone. The precursory phenomenon appears 1 to 7 days before the time of the seismic shock
Total electron content variations in the ionosphere before the Colima, Mexico, earthquake of 21 January 2003
En la actualidad se encuentra bien establecida la existencia de variaciones ionosféricas anómalas asociadas con el proceso de preparación de sismos fuertes (M>5). Con el fin de comprobar posibles variaciones ionosféricas que estuvieran relacionadas con el reciente temblor de Colima, México, M=7.8, del 21 de enero de 2003, se analizaron los datos de 5 receptores GPS de la red del Instituto Nacional de Geografía, Estadística e Informática (INEGI) de México. Se encontró que el TEC obtenido a partir de estos datos muestra anomalías importantes de dos a tres días antes del impacto sísmico, mientras que el coeficiente diario de correlación cruzada calculado para diferentes pares de receptores GPS presenta una caída importante dentro de un intervalo de uno a cinco días antes de dicho impacto. Por otra parte, la distribución horizontal (latitud-longitud) de las desviaciones del TEC con respecto a la media mensual para el día y la hora del sismo tuvo su máximo en un punto cercano a la proyección vertical en la ionosfera del epicentro del mismo. Hemos concluido a partir de esto que las variaciones observadas en la ionosfera durante el proceso de preparación y de realización del sismo pueden ser consideradas como posibles precursores de corto plazo del mismo
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