The mean frequency of recurrence of in-time-multidimensional events for drought analyses

International audienceDroughts are related with prolonged periods when moisture is significantly below normal values. Drought indices attempt to scale the main drought features to facilitate comparisons. Numerous indices are found in the literature based on different drought features. Many of them were created for particular places and specific objectives, and therefore not suitable to generalize the results. However, there have been attempts to develop a general index, which would provide full characterization of drought events. Two of the most well known are the Palmer Drought Severity Index (PDSI) and the Standard Precipitation Index (SPI). Each one has particular advantages and disadvantages. Still neither of them or any other includes a full representation of droughts in a single value index, being useful for all general application. The fact that droughts have a random nature prescribes the statistical theory for the foundation of a complete and generic index, which would meet this goal. In this work, a procedure that allows a complete statistical characterization of drought events is presented. Droughts are characterized, from a statistical point of view, based both on the deviation from a normal regime and persistence. The events are represented as multivariate ones, whose dimensionality depends on the duration. Equal duration events are discriminated through their deviations from normality. The mean frequency of recurrence (MFR) is theoretically derived for such multivariate events, and it is used to scale such deviations. Therefore, events with different dimensionalities can be compared on a common dimension of interest, the MFR. This may be used as a drought index for drought characterization, both for analyzing historical events and monitoring current conditions. It may also be applied to analyze precipitation, streamflows and other hydroclimatic records. Its statistical nature and its general conception support its universality. Results may be applied not only to drought analysis, but also to analyze other random natural hazards. Applications of the procedure for drought analysis in Texas (USA) and in Gibraltar (Iberian Peninsula) are made and compared with PDSI and SPI results. The MFR applied over drought analysis allows the representation of the main drought characteristics in a single value, based on the statistical feature of the phenomenon, and scaled on the mean frequency of recurrence

S wave velocity structure below central Mexico using high-resolution surface wave tomography

Shear wave velocity of the crust below central Mexico is estimated using surface wave dispersion measurements from regional earthquakes recorded on a dense, 500 km long linear seismic network. Vertical components of regional records from 90 well-located earthquakes were used to compute Rayleigh-wave group-velocity dispersion curves. A tomographic inversion, with high resolution in a zone close to the array, obtained for periods between 5 and 50 s reveals significant differences relative to a reference model, especially at larger periods (>30 s). A 2-D S wave velocity model is obtained from the inversion of local dispersion curves that were reconstructed from the tomographic solutions. The results show large differences, especially in the lower crust, among back-arc, volcanic arc, and fore-arc regions; they also show a well-resolved low-velocity zone just below the active part of the Trans Mexican Volcanic Belt (TMVB) suggesting the presence of a mantle wedge. Low densities in the back arc, inferred from the low shear wave velocities, can provide isostatic support for the TMVB

Impact of the Deficiency of Micronutrients on Patients with HIV/Aids

Introduction: HIV-AIDS is an infectious disease that damages the immune system, putting you at risk of serious infections and certain types of cancer. Micronutrient deficiency varies widely, depending on the population and stage of the disease. It can contribute to the weakening of the immune state and the worsening of the physical condition. Objective: To identify through the collection of nutritional information the consequences produced by the lack of micronutrients in patients with HIV-AIDS. Methodology: It was carried out through bibliographic reviews, scientific articles in order to find true and proven information on the effect that micronutrient deficiency has on people with HIV/AIDS. Results: It is shown that clinical deficiencies of some nutrients occur rapidly in response to dietary deficiencies, malabsorption, or altered metabolism, while those nutrients that have reserves in the body take longer to deplete. Discussion: The acquired immunodeficiency virus that causes AIDS; is associated with weight loss due to malnutrition. There are foods that can counteract many of the symptoms of the patient with HIV/AIDS, hence the importance of their knowledge. Conclusion: Micronutrient deficiency influences the immune system, accentuating the immunodeficiency that leads to AIDS. People living with this disease should have a balanced diet with Vitamins A, B, zinc and iron to strengthen the immune system, these offer a safe and economical treatment to slow the progression of the infection. Keywords: micronutrients, HIV, AIDS. RESUMEN Introducción: El VIH-SIDA es una enfermedad infecciosa que daña el sistema inmunitario lo que pone en riesgo de contraer infecciones graves y ciertos tipos de cáncer. La deficiencia de micronutrientes varía ampliamente, según la población y el estadio de la enfermedad; puede contribuir al debilitamiento del estado inmune y al empeoramiento de la condición física.  Objetivo: Identificar mediante la recopilación de información nutricional las consecuencias que produce la falta de micronutrientes en pacientes con VIH-SIDA. Metodología: Se realizó a través de revisiones bibliográficas, artículos científicos con el fin de encontrar información verídica y comprobada del efecto que tiene la deficiencia de micronutrientes en personas con VIH/SIDA.  Resultados: Se demuestra que las deficiencias clínicas de algunos nutrientes ocurren rápidamente en respuesta a deficiencias dietéticas, malabsorción, o metabolismo alterado, mientras que aquellos nutrientes que tienen reservas en el cuerpo tardan más en agotarse. Discusión: El virus de la inmunodeficiencia adquirida causante del SIDA; está asociada con la pérdida de peso por malnutrición. Hay muchos alimentos del grupo de los micronutrientes que minimizan manifestaciones clínicas en los enfermos el síndrome de inmunodeficiencia adquirida, siendo necesario saber cuáles son. Conclusiones: La deficiencia de micronutrientes influye en el sistema inmune, acentuando la inmunodeficiencia que lleva al SIDA. Las personas que viven con esta enfermedad deben tener una dieta balanceada con Vitaminas A, B, zinc y hierro para fortalecer el sistema inmunológico, estas ofrecen un tratamiento seguro y económico para retardar la progresión de la infección. Palabras claves: micronutrientes, VHI, SIDA

Analysis of the mechanical properties of wood attacked by Xylotrechus arvicola (Coleoptera: Cerambycidae) larvae, and its influence on the structural properties of the plant

Xylotrechus arvicola is an invasive insect on Vitis vinifera in the main wine-producing regions of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood and make galleries, which cause structural damages to the plant. The aim of this study was to investigate how grapevine wood infested by larvae affects the mechanical properties of the plant in comparation with those of uninfested wood. Samples of grapevine wood uninfested and infested by larvae were collected from vineyards. Compression and flexural strengths as well as simulated structures of grapevine wood in field, in relation to harvest weight by variety, were used to quantify the wood mechanical properties. Infested wood endured a lower strength and normal tension, and exhibited a reduction in the structural capacities in the simulation of harvest weight of 'Cabernet-Sauvignon' variety (up to 62.0 %). 'Tempranillo' (despite its high mechanical slenderness values) and 'Cabernet-Sauvignon', were the varieties that showed a higher resistance on trunks and branches, respectively. A lower bending moment was observed on the infested branches of all varieties. Changes in the mechanical properties of infested wood suggest a decrease in mechanical resistance of wood attacked by larvae that could contribute to the rupture of the infested grapevine over time. Grapevine wood attacked by X. arvicola larvae could be more sensitive to mechanical external factors in vineyards such as strong winds, harvest weight and vibration exerted by harvesting machines

Evaluación de la eficacia de plaguicidas químicos y alternativos en el control de pulgones en granado

El presente trabajo presenta los ensayos realizados durante las campañas de 2010 y 2011 sobre identificación de la fauna auxiliar presente, así como la eficacia y residuos de la aplicación de insecticidas químicos convencionales y alternativos para el control de áfidos en granado. Los ensayos se han llevado a cabo en dos parcelas experimentales sobre la variedad Mollar de Elche, en los municipios de Albatera y Elche, al sur de la Comunidad Valenciana. Los tratamientos insecticidas (uno o dos tratamientos anuales con un gasto de caldo de 1000 l/ha por tratamiento) se aplicaron en subparcelas en diseño aleatorio de bloques al azar, con tres repeticiones. Se evaluó la mortalidad de pulgones tras los tratamientos en brotes, flores y frutos. Los resultados obtenidos sugieren que la población de Aphis gossypii presenta resistencias a Pirimicarb. Los insecticidas de nueva generación Imidacloprid, Flonicamid y Acetamiprid, obtuvieron más del 95% de mortalidad de pulgones. Moderadamente efectivos fueron los tratamientos con jabón potásico, extracto de cítricos, piretrinas o Azadiractin, aunque la combinación de algunos de ellos, como el extracto de cítricos con piretrinas se mostró más efectiva. Los niveles de residuos en los frutos en el momento de la recolección fue en todos los casos, inferior al límite de determinación analítica

Directory of Atmospheric, Hydrographic and Biological datasets for the Canary Current Large Marine Ecosystem

Environmental and biological data-sets were recovered from oceanographic surveys and other observation sources (e.g. tide gauges) since the 40s. This rescue and mining exercise was carried out in cooperation with the countries bordering the CCLME and other nations undertaking research in the region (i.e. Morocco, Mauritania, Senegal, Gambia, Guinea, Guinea Bissau, Cape Verde, Spain, Norway, Germany and France). A total of 425 data-sets, 27 databases and 21 time-series sites have been identified in the area. A substantial part of them were rescued from archives supported in paper copy. Finally, a directory of meta-data referring 99 data-sets and data-bases has been published. This catalogue and the recovered data offer an exceptional opportunity for the researchers in the CCLME to study the dynamics and trends of a multiplicity of variables, and will enable them to create their own time-series, baselines and climatologies under a spatial and temporal perspective. It will produce new and valuable information on changes produced during the last 35 years in this region, going from climatic changes to shifts in species diversity and populations due to natural and human induced factors. This directory is the first result of the project “Enhancing oceanography capacities on Western Africa Countries” funded by the Spanish Agency for International Development Cooperation (AECID) and coordinated by the IOC-UNESCO and the IEO. The project aims to reinforce transboundary cooperation in the CCLME and to facilitate access and data flow to existing scientific information and its utilization by the scientists, politicians, industry and civil society.http://unesdoc.unesco.org/images/0023/002314/231430E.pd

Diagnosing tuberculous pleural effusion using clinical data and pleural fluid analysis A study of patients less than 40 years-old in an area with a high incidence of tuberculosis

SummaryBackgroundTuberculous pleural effusions (TPE) are common. The diagnosis is often problematic. As the determination of ADA is often unavailable in some countries, the aim of this study was to evaluate the diagnostic usefulness of other data from pleural fluid analysis, in young patients from populations with high prevalence of tuberculosis (TB).MethodsWe analysed 218 patients with pleural effusion (165 tuberculous, 21 infectious, 11 neoplastic, 16 miscellaneous, 3 idiopathic). We performed two regression models; one included pleural fluid ADA values (model 1), and the other without ADA (model 2).ResultsModel 1 selected two variables (ADA >35U/L) and lymphocytes (>31.5%) and correctly classified 216/218 effusions (1 false negative, 1 false positive). Model 2 (without ADA) selected three variables: lymphocytes (>31.5%), fever and cough, and correctly classified 207/218 effusions (8 false negatives, 3 false positives). The sensitivity of models 1 and 2 was 99.4% and 95.2%, specificity 98.1% and 94.3% and accuracy 99% and 95%.ConclusionsIn geographic areas with high prevalence of TB and a low prevalence of HIV, in young patients (≤40 years), it is possible to confidently diagnose TPE with either of the two regression tree models, with the utility of ADA providing superior sensitivity, specificity, and accuracy