3,830 research outputs found

    Primordial magnetic fields from preheating at the electroweak scale

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    We analyze the generation of helical magnetic fields during preheating in a model of low-scale electroweak (EW) hybrid inflation. We show how the inhomogeneities in the Higgs field, resulting from tachyonic preheating after inflation, seed the magnetic fields in a way analogous to that predicted by Vachaspati and Cornwall in the context of the EW symmetry breaking. At this stage, the helical nature of the generated magnetic fields is linked to the non-trivial winding of the Higgs-field. We analyze non-perturbatively the evolution of these helical seeds through the highly non-linear stages of symmetry breaking (SB) and beyond. Electroweak SB occurs via the nucleation and growth of Higgs bubbles which squeeze the magnetic fields into string-like structures. The W-boson charge density clusters in lumps around the magnetic strings. After symmetry breaking, a detailed analysis of the magnetic field Fourier spectrum shows two well differentiated components: a UV radiation tail at a temperature T ~ 0.23 m_higgs slowly growing with time, and an IR peak associated to the helical magnetic fields, which seems to follow inverse cascade. The system enters a regime in which we observe that both the amplitude (\rho_B/\rho_{EW} ~ 0.01) and the correlation length of the magnetic field grow linearly with time. During this stage of evolution we also observe a power-law growth in the helical susceptibility. These properties support the possibility that our scenario could provide the seeds eventually evolving into the microgauss fields observed today in galaxies and clusters of galaxies.Comment: 55 pages, late

    Conocimientos y prácticas de riesgo ante el VIH/SIDA en adolescentes de la Facultad de Planeación Urbana y Regional de la Universidad Autónoma del Estado de México

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    El VIH/SIDA en los últimos años se ha expandido de manera alarmante, traspasando las fronteras que inicialmente los asociaban a comportamientos específicos como la homosexualidad, la promiscuidad sexual y el consumo de drogas. En la actualidad la pandemia afecta en forma indiscriminada a diversos sectores de la sociedad, haciendo cada vez más difícil su control.Introducción: El VIH/SIDA ha tenido gran impacto en la población mundial. Actualmente 33.3 millones de personas viven con VIH/SIDA, y cerca de la mitad de los nuevos casos reportados se encuentran entre los 15 a los 24 años. Objetivo: Identificar los conocimientos y prácticas de riesgo ante el VIH en adolescentes de la Facultad de Planeación Urbana y Regional (FaPUR) de la Universidad Autónoma del Estado de México (UAEMEX) Materiales y métodos: Se realizó un estudio transversal, descriptivo y prospectivo, se aplicaron 200 encuestas a adolescentes de 17-19 años de ambos sexos que fueran alumnos de la FaPUR de la UAEMEX, durante el mes de Septiembre del año 2012 y se realizó un análisis estadístico descriptivo de la información obtenida. Resultados: Las principales características encontradas en los adolescentes fueron: la mayoría son del sexo masculino, de 18 años de edad, y con religión católica; su lugar de residencia es urbano, y con orientación sexual heterosexual, del total el 82% de los adolescentes tienen conocimientos suficientes sobre el VIH/SIDA y un 43% poseen de 1-4 prácticas de riesgo para adquirir la infección. Conclusiones: Los adolescentes de la FAPUR de la UAEMEX, poseen un nivel suficiente de conocimientos básicos sobre el VIH/SIDA, a pesar de esto siguen realizando prácticas de riesgo para adquirir el virus; lo que refleja de manera clara que aunque posean los cocimientos, estos no son traducidos a acciones y por lo tanto no son aplicados de manera preventiva y efectiva a su vida sexual

    Effect of flocculation on lipid extraction from Chlorella vulgaris Utex 1803 using response surface methodology

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    Microalgae are an attractive source of metabolites, such as lipids, proteins, pigments and carbohydrates, of potential interest to the pharmaceutical, food and energy sectors. The aim of this study was to evaluate the effect of flocculation on lipid extraction from Chlorella Vulgaris. A 3 3 experimental design was performed with STATISTICA 7.0 software in order to determine the effects of flocculant (AlCl 3 ) addition, pH and time. The best strategy of pH adjustment-flocculant addition was evaluated, followed by lipid extraction under optimal conditions. pH adjustment after the addition of flocculant provided higher flocculation efficiencies (87.2-98.9%) compared to adjustments made before adding the flocculant (67.8-85.9%). Experiments performed according to the experimental design led to a flocculation efficiency of 99.7% when 100 mg/L of AlCl 3 , pH 7 and a cultivation time of 18.3 days were used. The percentage of a lipid extract from the flocculated biomass was 2.7% and the flocculant did not affect the production of fatty acid methyl esters

    Artificial intelligence-based software (AID-FOREST) for tree detection: A new framework for fast and accurate forest inventorying using LiDAR point clouds

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    Forest inventories are essential to accurately estimate different dendrometric and forest stand parameters. However, classical forest inventories are time consuming, slow to conduct, sometimes inaccurate and costly. To address this problem, an efficient alternative approach has been sought and designed that will make this type of field work cheaper, faster, more accurate, and easier to complete. The implementation of this concept has required the development of a specifically designed software called "Artificial Intelligence for Digital Forest (AID-FOREST)", which is able to process point clouds obtained via mobile terrestrial laser scanning (MTLS) and then, to provide an array of multiple useful and accurate dendrometric and forest stand parameters. Singular characteristics of this approach are: No data pre-processing is required either pre-treatment of forest stand; fully automatic process once launched; no limitations by the size of the point cloud file and fast computations.To validate AID-FOREST, results provided by this software were compared against the obtained from in-situ classical forest inventories. To guaranty the soundness and generality of the comparison, different tree spe-cies, plot sizes, and tree densities were measured and analysed. A total of 76 plots (10,887 trees) were selected to conduct both a classic forest inventory reference method and a MTLS (ZEB-HORIZON, Geoslam, ltd.) scanning to obtain point clouds for AID-FOREST processing, known as the MTLS-AIDFOREST method. Thus, we compared the data collected by both methods estimating the average number of trees and diameter at breast height (DBH) for each plot. Moreover, 71 additional individual trees were scanned with MTLS and processed by AID-FOREST and were then felled and divided into logs measuring 1 m in length. This allowed us to accurately measure the DBH, total height, and total volume of the stems.When we compared the results obtained with each methodology, the mean detectability was 97% and ranged from 81.3 to 100%, with a bias (underestimation by MTLS-AIDFOREST method) in the number of trees per plot of 2.8% and a relative root-mean-square error (RMSE) of 9.2%. Species, plot size, and tree density did not significantly affect detectability. However, this parameter was significantly affected by the ecosystem visual complexity index (EVCI). The average DBH per plot was underestimated (but was not significantly different from 0) by the MTLS-AIDFOREST, with the average bias for pooled data being 1.8% with a RMSE of 7.5%. Similarly, there was no statistically significant differences between the two distribution functions of the DBH at the 95.0% confidence level.Regarding the individual tree parameters, MTLS-AIDFOREST underestimated DBH by 0.16 % (RMSE = 5.2 %) and overestimated the stem volume (Vt) by 1.37 % (RMSE = 14.3 %, although the BIAS was not statistically significantly different from 0). However, the MTLS-AIDFOREST method overestimated the total height (Ht) of the trees by a mean 1.33 m (5.1 %; relative RMSE = 11.5 %), because of the different height concepts measured by both methodological approaches. Finally, AID-FOREST required 30 to 66 min per ha-1 to fully automatically process the point cloud data from the *.las file corresponding to a given hectare plot. Thus, applying our MTLS-AIDFOREST methodology to make full forest inventories, required a 57.3 % of the time required to perform classical plot forest inventories (excluding the data postprocessing time in the latter case). A free trial of AID -FOREST can be requested at [email protected]

    Oleic acid and peanut oil high in oleic acid reverse the inhibitory effect of insulin production of the inflammatory cytokine TNF-α both in vitro and in vivo systems

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    <p>Abstract</p> <p>Background</p> <p>Chronic inflammation is a key player in pathogenesis. The inflammatory cytokine, tumor necrosis factor-alpha is a well known inflammatory protein, and has been a therapeutic target for the treatment of diseases such as Rheumatoid Arthritis and Crohn's Disease. Obesity is a well known risk factor for developing non-insulin dependent diabetes melitus. Adipose tissue has been shown to produce tumor necrosis factor-alpha, which has the ability to reduce insulin secretion and induce insulin resistance. Based on these observations, we sought to investigate the impact of unsaturated fatty acids such as oleic acid in the presence of TNF-α in terms of insulin production, the molecular mechanisms involved and the in vivo effect of a diet high in oleic acid on a mouse model of type II diabetes, KKA<sup>y</sup>.</p> <p>Methods</p> <p>The rat pancreatic beta cell line INS-1 was used as a cell biological model since it exhibits glucose dependent insulin secretion. Insulin production assessment was carried out using enzyme linked immunosorbent assay and cAMP quantification with competitive ELISA. Viability of TNF-α and oleic acid treated cells was evaluated using flow cytometry. PPAR-γ translocation was assessed using a PPRE based ELISA system. In vivo studies were carried out on adult male KKA<sup>y </sup>mice and glucose levels were measured with a glucometer.</p> <p>Results</p> <p>Oleic acid and peanut oil high in oleic acid were able to enhance insulin production in INS-1. TNF-α inhibited insulin production but pre-treatment with oleic acid reversed this inhibitory effect. The viability status of INS-1 cells treated with TNF-α and oleic acid was not affected. Translocation of the peroxisome proliferator- activated receptor transcription factor to the nucleus was elevated in oleic acid treated cells. Finally, type II diabetic mice that were administered a high oleic acid diet derived from peanut oil, had decreased glucose levels compared to animals administered a high fat diet with no oleic acid.</p> <p>Conclusion</p> <p>Oleic acid was found to be effective in reversing the inhibitory effect in insulin production of the inflammatory cytokine TNF-α. This finding is consistent with the reported therapeutic characteristics of other monounsaturated and polyunsaturated fatty acids. Furthermore, a diet high in oleic acid, which can be easily achieved through consumption of peanuts and olive oil, can have a beneficial effect in type II diabetes and ultimately reverse the negative effects of inflammatory cytokines observed in obesity and non insulin dependent diabetes mellitus.</p

    Crustal and Mantle Structure Beneath the Southern Payenia Volcanic Province Using Gravity and Magnetic Data

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    The Auca Mahuida volcanic field lies on the southernmost Payenia Volcanic Province, one of the broadest retroarc volcanic plateaux in the southern Central Andes (~38°S). This voluminous basaltic flooding of Quaternary age was originated from a deep asthenospheric source, interpreted as a mantle plume product of changing slab dynamics. The geometry of this source is deduced from magnetotelluric data, but the limited spatial coverage of this array does not allow a detailed resolution of this anomaly. In order to present a detailed geometry of the conductive anomaly and related crustal magmatic bodies, we used multiple data sources. We combined Magnetic and Bouguer anomalies, Curie isotherm depth (T c ), Elastic Thickness (T e ) and Moho depth derived from the Global Earth Magnetic Anomaly Grid (EMAG2) and terrestrial gravity measurements, all together in a holistic geophysical analysis. The magnetic data depict a nearly 200-km-in-diameter circular anomaly that would correspond to a dense body according to the Bouguer anomaly. Geoid data from the Gravity Field Model (EIGEN-6c4) have been filtered in order to isolate deeper mass influences and visualize the asthenospheric upwelling previously described from magnetotelluric data. Moho inversion yields a crustal attenuation at 36- to 32-km depth coinciding with T e below 20-km depth and a shallow T c (≤15-km depth) at the site where Geoid positive undulation was calculated. Finally, surface analysis allowed defining a topographic swell, compatible with the dimensions of the identified magnetic anomaly, where the main rivers deviated, potentially due to a recent base level change.Fil: Astort, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Colavitto, Bruno. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Sagripanti, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Garcia, Hector Pedro Antonio. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Echaurren Gonzalez, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Soler, Santiago Rubén. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Ruíz, F.. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Folguera Telichevsky, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

    Los B-agonistas adrenérgicos como modificadores metabólicos y su efecto en la producción, calidad e inocuidad de la carne de bovinos y ovinos: una revisión

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    Los B-agonistas adrenérgicos (BAA) se han utilizado en la producción animal, incluidos los rumiantes, propiciando una mayor eficiencia de uso del alimento, la cual se manifiesta en mejores características de la canal, así como en la composición química de la carne, al reducir el contenido de grasa y aumentar el de proteína. En el presente documento se revisa la estructura química y los mecanismos de acción de los BAA en el metabolismo de los nutrientes, así como resultados de investigaciones sobre BAA usados en la producción animal y sus efectos en la eficiencia de uso de los nutrientes que se traducen en mejoras en el crecimiento y en la calidad de la carne, principalmente en sistemas de alimentación intensiva; también se presenta información sobre la producción e inocuidad de la carne para evitar el uso de sustancias no aprobadas en la nutrición animal, por representar riesgos en la salud pública.Los β-agonistas adrenérgicos (βAA) se han utilizado en la producción animal, incluidos los rumiantes, propiciando una mayor eÀciencia de uso del alimento, la cual se maniÀesta en mejores características de la canal, así como en la composición química de la carne, al reducir el contenido de grasa y aumentar el de proteína. En el presente documento se revisa la estructura química y los mecanismos de acción de los βAA en el metabolismo de los nutrientes, así como resultados de investigaciones sobre βAA usados en la producción animal y sus efectos en la eÀciencia de uso de los nutrientes que se traducen en mejoras en el crecimiento y en la calidad de la carne, principalmente en sistemas de alimentación intensiva; también se presenta información sobre la producción e inocuidad de la carne para evitar el uso de sustancias no aprobadas en la nutrición animal, por representar riesgos en la salud pública

    Velocidad media de infiltración en un vertisol bajo distintos sistemas de labranza

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    Soil compaction is regarded as the most serious environmental problem caused by conventional agriculture. Few studies are concerned with the assessment of soil compaction using infiltration speed, specifically in the Vertisol soil characteristic of the main maize producing area of the Toluca-Atlacomulco Valley in central Mexico. The aim of this research was to examine the effect on infiltration speed and penetration resistance of a Vertisol soil when compacted by wheeled agricultural traffic in three different types of tillage systems: zero, minimal and conventional. Penetration resistance was measured on the wheel track with a portable digital penetrometer, and the mean infiltration speed was determined according to the double cylinder infiltrometer method. The pressure exerted by the number of wheeled traffic passes increased Vertisol soil compaction at 30 cm depth. Even though the benefits of zero tillage were similar to those showed by mínimum tillage during the experimental period, minimum tillage reported the highest infiltration spee

    Divergent functions of the Arabidopsis mitochondrial SCO proteins: HCC1 is essential for COX activity while HCC2 is involved in the UV-B stress response

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    The two related putative cytochrome c oxidase (COX) assembly factors HCC1 and HCC2 from Arabidopsis thaliana are Homologs of the yeast Copper Chaperones Sco1p and Sco2p. The hcc1 null mutation was previously shown to be embryo lethal while the disruption of the HCC2 gene function had no obvious effect on plant development, but increased the expression of stress-responsive genes. Both HCC1 and HCC2 contain a thioredoxin domain, but only HCC1 carries a Cu-binding motif also found in Sco1p and Sco2p. In order to investigate the physiological implications suggested by this difference, various hcc1 and hcc2 mutants were generated and analyzed. The lethality of the hcc1 knockout mutation was rescued by complementation with the HCC1 gene under the control of the embryo-specific promoter ABSCISIC ACID INSENSITIVE 3. However, the complemented seedlings did not grow into mature plants, underscoring the general importance of HCC1 for plant growth. The HCC2 homolog was shown to localize to mitochondria like HCC1, yet the function of HCC2 is evidently different, because two hcc2 knockout lines developed normally and exhibited only mild growth suppression compared with the wild type (WT). However, hcc2 knockouts were more sensitive to UV-B treatment than the WT. Complementation of the hcc2 knockout with HCC2 rescued the UV-B-sensitive phenotype. In agreement with this, exposure of wild-type plants to UV-B led to an increase of HCC2 transcripts. In order to corroborate a function of HCC1 and HCC2 in COX biogenesis, COX activity of hcc1 and hcc2 mutants was compared. While the loss of HCC2 function had no significant effect on COX activity, the disruption of one HCC1 gene copy was enough to suppress respiration by more than half compared with the WT. Therefore, we conclude that HCC1 is essential for COX function, most likely by delivering Cu to the catalytic center. HCC2, on the other hand, seems to be involved directly or indirectly in UV-B-stress responses
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