1,295 research outputs found
Diversity of N2-fixing cyanobacteria from Andalusian paddy fields and analysis of their potential as bioinoculants
The marshes of the Guadalquivir River contain the largest area of rice cultivation in Spain, where more than 40,000 ha are used every year for rice production. These wetland areas provide a perfect place for rice cultivation, and represent a unique aquaticterrestrial habitat that hold more wintering waterfowl than any other European wetland.
Paddies require large amounts nitrogen and phosphorus for their growth, development and production. Though, flooded conditions used for rice cultivation drastically diminish efficiency inorganic nitrogen fertilizers, being only 30–40% used by the plant, and in some cases even less. Large amounts of nitrogen fertilizers are dissolved in the surface water and lost, causing environmental pollution and health problems due to losses through N2O and NO volatilization, denitrification, and leaching (Ishii et al., 2011)
Comparación entre modelo browniano, a través de la metodología Box-JenKins y el análisis multifractal: Aplicación al sector financiero
Tesis para obtener el grado de Licenciado en ActuaríaEl objetivo del estudio en el presente trabajo es plantear un modelo de identificación al supuesto de memoria larga para analizar el comportamiento futuro de las variables financieras del sector mexicano, como lo es el tipo de cambio peso/dólar, acciones bursátiles, o cualquier instrumento que presente volatilidad diaria en su movimiento; a través de una metodología innovadora basada en el análisis multifractal, wavelets y la teoría de los mercados fractales. Los resultados obtenidos con la propuesta planteada serán comparados con la metodología Box-Jenkins basada en una serie de tiempo que exhibe un desplazamiento de carácter browniano.
Además, en este estudio se observará la potencialidad que presentan los modelos con características multifractales, comparándolo con la metodología box-Jenkins, al ser esta conocida y aplicada en los mercados financieros por los últimos 50 años, impulsando de esta forma a los fractales como una técnica alterna de estimación para variables que presentan un grado alto de volatilidad en sus componentes
Planificación en zonas de conflicto y posconflicto usando evidencia científica que articuló a los sectores público y privado
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Carbon and Nitrogen Isotopic Signatures of Hair, Nail, and Breath from tropical African Human Populations
RATIONALE: Stable isotopic analyses are increasingly used to study the diets of past and present human populations. Yet, the carbon and nitrogen isotopic data of modern human diets collected so far are biased towards Europe and North America. Here, we address this gap by reporting on the dietary isotopic signatures of six tropical African communities: El Molo, Turkana (Kerio), Luhya (Webuye), Luhya (Port Victoria), and Luo (Port Victoria) from Kenya, and Baka from Cameroon; representing four subsistence strategies: fishing, pastoralism, agriculturalism, and hunter-gatherer. METHODS: We used EA-CF-IRMS to measure the carbon and nitrogen isotopic ratios of hair (n = 134) and nail (n = 80), and the carbon isotopic ratios of breath (n = 184) from these communities, as well as the carbon and nitrogen isotopic ratios of some food samples from the Kenyan communities. RESULTS: We expand on the known range of δ13 C values in human hair through the hunter-gatherer Baka, with a diet based on C3 plants, and through the agriculturalist Luhya (Webuye), with a diet based on C4 plants. In addition, we found that the consumption of fish from East African lakes is difficult to detect isotopically due to the combined effects of high nitrogen isotopic ratios of plants and the low nitrogen isotopic ratios of fish. Finally, we found that some of the communities studied are markedly changing their diets through increasing sedentism and urbanization. CONCLUSION: Our findings contribute substantially to the understanding of the environmental, demographic and economic dynamics that affect the dietary landscape of different tropical populations of Africa. These results highlight the importance of studying a broader sample of human populations and their diet, with a focus on their precise context - both from an isotopic and more general anthropological perspectives.This study was funded by a European Research Council Advanced Award to MML (In-Africa Project, ERC 295907), and carried out with permission from the National Commission for Science, Technology and Innovation, Kenya, No. NACOSTI/P/15/2669/4758
Simultaneous Minimization of Energy Losses and Greenhouse Gas Emissions in AC Distribution Networks Using BESS
The problem of the optimal operation of battery energy storage systems (BESSs) in AC grids is addressed in this paper from the point of view of multi-objective optimization. A nonlinear programming (NLP) model is presented to minimize the total emissions of contaminant gasses to the atmosphere and costs of daily energy losses simultaneously, considering the AC grid complete model. The BESSs are modeled with their linear relation between the state-of-charge and the active power injection/absorption. The Pareto front for the multi-objective optimization NLP model is reached through the general algebraic modeling system, i.e., GAMS, implementing the pondered optimization approach using weighting factors for each objective function. Numerical results in the IEEE 33-bus and IEEE 69-node test feeders demonstrate the multi-objective nature of this optimization problem and the multiple possibilities that allow the grid operators to carry out an efficient operation of their distribution networks when BESS and renewable energy resources are introduced.Universidad Tecnológica de Bolíva
CXCL12 is displayed by rheumatoid endothelial cells through its basic amino-terminal motif on heparan sulfate proteoglycans
The chemokine CXCL12 (also known as stromal cell-derived factor, SDF-1) is constitutively expressed by stromal resident cells and is involved in the homeostatic and inflammatory traffic of leukocytes. Binding of CXCL12 to glycosaminoglycans on endothelial cells (ECs) is supposed to be relevant to the regulation of leukocyte diapedesis and neoangiogenesis during inflammatory responses. To improve our understanding of the relevance of this process to rheumatoid arthritis (RA), we have studied the mechanisms of presentation of exogenous CXCL12 by cultured RA ECs. RA synovial tissues had higher levels of CXCL12 on the endothelium than osteoarthritis (OA) tissues; in both, CXCL12 colocalized to heparan sulfate proteoglycans (HSPGs) and high endothelial venules. In cultured RA ECs, exogenous CXCL12α was able to bind in a CXCR4-independent manner to surface HSPGs. Desulfation of RA EC HSPGs by pretreatment with sodium chlorate, or by replacing in a synthetic CXCL12α the residues Lys24 and Lys27 by Ser (CXCL12α-K2427S), decreased or abrogated the ability of the chemokine to bind to RA ECs. Ex vivo, synovial ECs from patients with either OA or RA displayed a higher CXCL12-binding capacity than human umbilical vein ECs (HUVECs), and in HUVECs the binding of CXCL12 was increased on exposure to tumor necrosis factor-α or lymphotoxin-α(1)β(2). Our findings indicate that CXCL12 binds to HSPGs on ECs of RA synovium. The phenomenon relates to the interaction of HSPGs with a CXCL12 domain with net positive surface charge located in the first β strand, which encompasses a canonical BXBB HSPG-binding motif. Furthermore, we show that the attachment of CXCL12 to HSPGs is upregulated by inflammatory cytokines. Both the upregulation of a constitutive chemokine during chronic inflammation and the HSPG-dependent immobilization of CXCL12 in EC surfaces are potential sites for therapeutic intervention
Genome-Wide Association Analysis for Stem Cross Section Properties, Height and Heading Date in a Collection of Spanish Durum Wheat Landraces
Durum wheat landraces have a high potential for breeding but they remain underexploited due to several factors, including the insufficient evaluation of these plant materials and the lack of efficient selection tools for transferring target traits into elite backgrounds. In this work, we characterized 150 accessions of the Spanish durum wheat collection for stem cross section, height and heading date. Continuous variation and high heritabilities were recorded for the stem area, pith area, pith diameter, culm wall thickness, height and heading date. The accessions were genotyped with DArTSeq markers, which were aligned to the durum wheat ‘Svevo’ genome. The markers corresponding to genes, with a minor allele frequency above 5% and less than 10% of missing data, were used for genome-wide association scan analysis. Twenty-nine marker-trait associations (MTAs) were identified and compared with the positions of previously known QTLs. MTAs for height and heading date co-localized with the QTLs for these traits. In addition, all the MTAs for stem traits in chromosome 2B were located in the corresponding synteny regions of the markers associated with lodging in bread wheat. Finally, several MTAs for stem traits co-located with the QTL for wheat stem sawfly (WSS) resistance. The results presented herein reveal the same genomic regions in chromosome 2B are involved in the genetic control of stem traits and lodging tolerance in both durum and bread wheat. In addition, these results suggest the importance of stem traits for WSS resistance and the potential of these landraces as donors for lodging tolerance and WSS resistance enhancement. In this context, the MTAs for stem-related traits identified in this work can serve as a reference for further development of markers for the introgression of target traits into elite materialThis research was funded by the Instituto de Investigación y Formación Agraria y Pesquera
(IFAPA), Junta de Andalucía, grant number AVA-AVA2019.020 cofounded at 80% by FEDER. C.M.A.,
J.S. and S.G.A. are members of the FiRCMe Network, funded by Ministerio de Economía, Industria
y Competitividad (AGL2016-81855-REDT). M.D.R.-R. was the recipient of a fellowship from the
Ministerio de Ciencia, Innovación y Universidades (PRE2018-084037)
Effect of Defoliation Frequency on Forage Yield from Intensive Silvopastoral Systems Compared to a Monoculture Grassland
Livestock production in the tropical regions of the world faces serious constraints as a result of climate change. Monoculture based pastures require the use of large amounts of nitrogen fertilizers to sustain production throughout the year. In general terms, tropical grasses are of low quality and when consumed by ruminant species, contribute to the emission of greenhouse gases (methane, carbon dioxide and nitrous oxide) (Herrero et al. 2009; Place et al. 2009). The establishment of intensive silvopastoral systems (iSPS) with associated shrubs legumes and grasses can increase the yield and quality of forage as well as fixation and transfer of atmospheric nitrogen (N) (Murgueitio et al. 2011). Therefore, the costs of nitrogen fertilizers and the emissions of greenhouse gases under practical conditions can be reduced. The intensive silvopastoral system is a kind of agroforestal practice that it is environmentally friendly and at the same time improves productivity of livestock systems. However, several aspects of its management have not been fully evaluated.
This is the case of the response to defoliation, which is an important management factor associated to the overall biomass productivity (Solorio 2005)
Spontaneous Hemopneumothorax: A Case Report
El hemoneumotórax espontáneo es una condición inusual, caracterizada por la acumulación de aire y
sangre en la cavidad pleural, no precedida por trauma. La radiografía de tórax es la herramienta principal
en el diagnóstico de esta entidad. Se presenta el caso de un hombre de 22 años con hemoneumotórax
espontáneo. El paciente se recuperó sin complicaciones luego de la cirugía.Spontaneous hemopneumothorax is an unusual condition, characterized by the accumulation of air and
blood in the pleural cavity, not preceded by trauma. Chest radiography is the main tool in the diagnosis
of this entity. We present, a case of a 22-year-old male with spontaneous hemopneumothorax. The
patient recovered after surgery with no complications
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