184 research outputs found

    Fractal dimension analysis of the magnetic time series associated with the volcanic activity of Popocatépetl

    Get PDF
    Fractal analysis of the total magnetic field (TMF) time series from 1997 to 2003 at Popocatépetl Volcano is performed and compared with the TMF-series of the Teoloyucan Magnetic Observatory, 100 km away. Using Higuchi's fractal dimension method (<i>D</i>). The <i>D</i> changes over time for both series were computed. It was observed, when the time windows used to compute <i>D</i> increase in length, both series show nearly the same behavior. Some criteria of comparison were employed to discriminate the local effects inherent to volcano-magnetism. The simultaneous maximum in <i>D</i> (1.8) of the TMF series at Popocatépetl Volcano and the recovered volcanic activity indicates a scaling relation of the TMF at Popocatépetl Volcano and demonstrates a link between the magnetic field and volcanic activity

    Adubação potássica na qualidade de pêssegos.

    Get PDF
    Para frutíferas de caroço o potássio (K) está relacionado com a qualidade dos frutos. O objetivo deste trabalho foi avaliar diferentes doses de adubação potássica nas características físico-químicas e compostos bioativos de frutos de pessegueiros ?Esmeralda?. O experimento foi desenvolvido em pomar comercial no município de Morro Redondo, Rio Grande do Sul, Brasil, entre as safras de 2014 e 2017. As doses de potássio aplicadas foram 0, 40, 80, 120 e 160 Kg K2O ha-1. Avaliou-se: coloração da polpa, firmeza da casca e da polpa, sólidos solúveis, pH, acidez titulável, relação SS/AT, compostos fenólicos totais, carotenoides totais e atividade antioxidante. O aumento das doses de K reduziu o teor de compostos fenólicos e a atividade antioxidante nos pêssegos nessa mesma safra. Os parâmetros de qualidade dos frutos, como a acidez titulável e firmeza da polpa não apresentaram alterações com a adubação potássica dos pessegueiros nas quatro safras avaliadas. Entretanto, os sólidos solúveis, relação SS/AT, croma, °Hue, firmeza de casca e compostos bioativos são influenciados pelas doses de K, mas dependem também das condições climáticas e da safra em análise

    3D Gravity Modeling of Complex Salt Features in the Southern Gulf of Mexico

    Get PDF
    We present a three-dimensional (3D) gravity modeling and inversion approach and its application to complex geological settings characterized by several allochthonous salt bodies embedded in terrigenous sediments. Synthetic gravity data were computed for 3D forward modeling of salt bodies interpreted from Prestack Depth Migration (PSDM) seismic images. Density contrasts for the salt bodies surrounded by sedimentary units are derived from density-compaction curves for the northern Gulf of Mexico’s oil exploration surveys. By integrating results from different shape- and depth-source estimation algorithms, we built an initial model for the gravity anomaly inversion. We then applied a numerically optimized 3D simulated annealing gravity inversion method. The inverted 3D density model successfully retrieves the synthetic salt body ensemble. Results highlight the significance of integrating high-resolution potential field data for salt and subsalt imaging in oil exploration

    Effect of Supplementation of Dairy Cows under Cut and Carry or Grazing of Irrigated Cultivated Pastures in Small Scale Dairy Systems in the Highlands of Central Mexico

    Get PDF
    Small-scale dairy systems in Mexico represent over 78% of dairy farms and produce 37% of the nation’s milk, and have an important role in reducing rural poverty. Small-scale dairy systems are defined by having herds of 3 to 35 cows plus replacements, and rely mostly on the family for labour. In the central highlands, many small-scale dairy farms base the feeding of herds on irrigated cultivated pastures of ryegrass (Lolium multiflorum, L. perenne) – white clover (Trifolium repens), mostly under cut-and-carry by hand with scythes, straws, and large amounts of commercial compound concentrates that result in high feeding costs and low economic sustainability (Fadul-Pacheco et al., 2013). One option to optimize the use of resources in these systems is to change the use of grasslands to intensive grazing that result in lower feeding costs when compared to cut-and-carry strategies. Also, the high protein content of pasture may meet requirements for moderate yields by dairy cows, so that commercial concentrates may be substituted by lower protein, lower cost supplements like ground maize grain and remove the straws of the diets

    A complete sample of bright Swift Long Gamma-Ray Bursts: Sample presentation, Luminosity Function and evolution

    Full text link
    We present a carefully selected sub-sample of Swift Long Gamma-ray Bursts (GRBs), that is complete in redshift. The sample is constructed by considering only bursts with favorable observing conditions for ground-based follow-up searches, that are bright in the 15-150 keV Swift/BAT band, i.e. with 1-s peak photon fluxes in excess to 2.6 ph s^-1 cm^-2. The sample is composed by 58 bursts, 52 of them with redshift for a completeness level of 90%, while another two have a redshift constraint, reaching a completeness level of 95%. For only three bursts we have no constraint on the redshift. The high level of redshift completeness allows us for the first time to constrain the GRB luminosity function and its evolution with cosmic times in a unbiased way. We find that strong evolution in luminosity (d_l=2.3\pm 0.6) or in density (d_d=1.7\pm 0.5) is required in order to account for the observations. The derived redshift distribution in the two scenarios are consistent with each other, in spite of their different intrinsic redshift distribution. This calls for other indicators to distinguish among different evolution models. Complete samples are at the base of any population studies. In future works we will use this unique sample of Swift bright GRBs to study the properties of the population of long GRBs.Comment: 7 pages, 3 figures, 2 tables; ApJ in pres

    Effect of potassium fertilizers associated with cold storage on peach (Prunus persica L.) quality.

    Get PDF
    Potassium (K) fertilization may affect peach quality and preservation. This study aimed at evaluating the effect of doses of K on physico-chemical and functional characteristics of "Sensação" peaches in the postharvest period. Mass loss, pulp color, total solublesolids, titratable acidity, pH, pulp and skin firmness, total concentrations of phenolic compounds and carotenoids and antioxidant activity were evaluated in fruits. The experiment was a randomized block design in a 5x3 factorial scheme, five doses of fertilizers (0, 40, 80, 120 and 160 Kg ha-1K2O) and three storage periods (harvest day, 10 days and 20 days in cold storage at 1±1ºC, followed by a day of simulated commercialization at 20±1ºC). Mass loss, pulp firmness, phenolic compounds, antioxidant activity and carotenoids decreased when fruit underwent cold storage, independent of the dosage of K fertilization. Doses of40 and160 kg ha-1K2O applied to the soil lead to a larger number of phenolic compoundsand higher antioxidant activity in fruits at harvest time. After cold storage, fertilization with160 kg ha-1K2O exhibited the highest antioxidant activity and the lowest mass loss in fruits. Increase in doses of K strengthened the color of peach pulp

    Bioactive compounds and physical-chemical characteristics of two genotypes of peach trees submitted to nitrogen fertilization.

    Get PDF
    Nitrogen, which is the primary nutrient peach trees need, may affect their fruit quality. Thus, this study aimed at evaluating the effect of nitrogen fertilization on two genotypes of peach trees, regarding their fruit quality, in three consecutive crops. The experiment was carried out in the experimental area that belongs to the Embrapa Clima Temperado, located in Pelotas, Rio Grande do Sul (RS), Brazil, from 2016, 2016, 2017 and 2018. Four doses of nitrogen (0, 60, 120 and 180 Kg ha-1) and two peach tree genotypes (?Cascata 1513? and ?Cascata 1067?) were used. For the fruit, we evaluated epidermis color, pulp firmness, epidermis firmness, soluble solids concentration, titratable acidity, concentration of total phenolic compounds, anthocyanins and antioxidant activity. Fruit underwent physical, chemical and bioactive compound analyses. Results showed that the highest dose of nitrogen (180 Kg ha-1) applied to the soil retards fruit ripening, while no application of nitrogen fertilization brings fruit maturation forward. Nitrogen fertilization via soil does not favor anthocyanins in fruit. Doses of 60 and 120 Kg ha-1 of nitrogen are recommended because they lead to improvement in peach color, epidermis firmness and acidity. Peach tree genotypes influence soluble solids, juice pH, phenolic compounds and antioxidant activity of their fruit

    Adubação potássica na qualidade de frutos de pessegueiro.

    Get PDF
    Para pessegueiros produzidos na região sul do Brasil ainda são escassas as informações sobre a influência da adubação potássica sobre a qualidade dos frutos. Deste modo, o presente trabalho teve como objetivo avaliar os atributos físico-químicos e compostos bioativos dos frutos de pessegueiros submetidos a diferentes doses de potássio aplicadas no solo por três safras consecutivas. O experimento foi realizado estudando a cultivar Sensação em um pomar comercial no município de Morro Redondo, RS ? Brasil, durante as safras de 2016, 2017 e 2018. Os pessegueiros da cultivar Sensação foram adubados com potássio (K) nas doses de 0, 40, 80, 120 e 160 kg ha-1 de K2O na forma de cloreto de potássio, aplicadas na superfície do solo. Após a colheita foram determinados os teores de sólidos solúveis (SS), acidez titulável (AT), relação SS/AT, pH, coloração da polpa, firmeza da epiderme e da polpa, teor de carotenoides totais, compostos fenólicos totais e atividade antioxidante. A firmeza da epiderme, a relação SS/AT e a concentração de carotenoides dos pêssegos responderam à adubação potássica, mas apenas em alguns ciclos de produção. Os parâmetros de coloração, firmeza da polpa, sólidos solúveis, pH do suco, fenóis totais e atividade antioxidante dos pêssegos não alteraram em decorrência da aplicação de potássio ao solo

    Transcriptoma en mexicanos: metodología para analizar el perfil de expresión genética de gran escala en muestras simultáneas de tejido muscular, adiposo y linfocitos obtenidas en un mismo individuo

    Get PDF
    Describir la metodología de análisis de múltiples trasncritos con técnicas de microarreglo en biopsisas simultáneas de tejido muscular, adiposo y sangre en un mismo individuo, como parte de la estandarización del estudio GEMM (Genética de las enfermedades Metabólicas en México
    corecore