446 research outputs found
Determinantes del número de relaciones bancarias en Colombia
En este documento se realiza una exploración inicial sobre los determinantes del número de relaciones bancarias del sector corporativo privado de Colombia. Siguiendo otros estudios similares que se han realizado para distintos países, se utilizan modelos de datos de cuenta y se estima un modelo de regresión Poisson y un modelo de regresión Binomial Negativo para hallar los determinantes de la variable de interés. Encontramos que los datos presentan sobredispersión, razón por la cual el modelo de regresión Binomial Negativo es más adecuado que el modelo de regresión Poisson en este contexto. Dentro de este ejercicio se encuentra que las variables de liquidez, tamaño de la firma, composición de la deuda, eficiencia, la tasa activa real y la tasa de crecimiento del PIB, resultan ser importantes en la determinación del número de relaciones bancarias. El hecho que las relaciones bancarias sean afectadas por la actividad económica podría sugerir que durante los tiempos de desaceleración económica las empresas buscan fuentes alternativas de financiamiento.Bancos, Relaciones bancarias, modelos de datos de cuenta. Classification JEL: E59, A11.
An early warning for better planning of agricultural expansion and biodiversity conservation in the Orinoco high plains of Colombia
The eastern high plains of the Orinoco region in Colombia are known as ‘Altillanura’. They are considered the future agricultural frontier of Colombia. Unfortunately, an agricultural expansion without taking in consideration areas of high biodiversity and conservation of fragile ecosystems that are ecologically irreplaceable will likely fail in providing a sustainable grow. An orderly management planning of the territory based on scientific evidence is currently lacking for this region. Specifically, studies that combine biodiversity data and agricultural information are a major research gap. This study analyses the spatial patterns of species richness and endemism of flora and fauna at the site and subregional levels. We compared the spatial changes of biodiversity patterns with aspects related to the expansion of the agricultural frontier and its possible impacts. We found a west-to-east pattern; sites closer to the Andes were more exposed to ecological degradation than those in the east. Santa Rosalía and Puerto Lopez are the municipalities with the most remarkable species diversity. Conversely, La Primavera municipality has the most significant number of endemic species. Our spatial changes results raise the alarm showing that hotspots of diversity closer to the municipalities of Puerto Lopez and Puerto Gaitan are under more pressure than underdeveloped municipalities (La Primavera and Puerto Carreño). Our results could serve as a baseline to identify spatial changes of agrobiodiversity and a guideline for land-use planning, regional policies and local decision-makers to improve regional development in Colombia’s eastern plains region
Strawberry (Fragaria x ananassa Duch.) production in a vertical hydroponic greenhouse system
Objective: A vertical hydroponic greenhouse system (VHGS) was designed and built to evaluat two strawberry varieties (Festival and San Andreas), in two planting densities per pot (40 and 54 plants/m 2 ) and three elevation levels (high, medium, and low).
Design/Methodology/Approach: At 126 days after transplanting (dat), the Festival variety showed significant differences in the number of leaves and in the crown diameter.
Results: The vertical hydroponic greenhouse system had a high fruit yield (21 kg m2 ): i.e., this productionsystem is up to 35 % more efficient than the open field cultivation system or the multi-tunnel greenhouse system. There was a positive correlation between the number (r 2 =0.89), diameter (r 2 =0.54), and weight (r 2 =0.40) of the fruits and the total yield. Planting density did not show a significant effect on plant growth, yield, and fruit quality. The vertical pot system did not show differences between elevation levels. This production system is a viable option for populations in places with a scarcity of water and to obtain fruits with guaranteed food safety
Phylogenetic diversity and conservation of crop wild relatives in Colombia
Crop wild relatives (CWR) are an important agricultural resource as they contain genetic traits not found in cultivated species due to localized adaptation to unique environmental and climatic conditions. Phylogenetic diversity (PD) measures the evolutionary relationship of species using the tree of life. Our knowledge of CWR PD in neotropical regions is in its infancy. We analysed the distribution of CWR PD across Colombia and assessed its conservation status. The areas with the largest concentration of PD were identified as being in the northern part of the central and western Andean mountain ranges and the Pacific region. These centres of high PD were comprised of predominantly short and closely related branches, mostly of species of wild tomatoes and black peppers. In contrast, the CWR PD in the lowland ecosystems of the Amazon and Orinoquia regions had deeply diverging clades predominantly represented by long and distantly related branches (i.e. tuberous roots, grains and cacao). We categorized 50 (52.6%) of the CWR species as 'high priority', 36 as 'medium priority' and nine as 'low priority' for further ex-situ and in situ conservation actions. New areas of high PD and richness with large ex-situ gap collections were identified mainly in the northern part of the Andes of Colombia. We found that 56% of the grid cells with the highest PD values were unprotected. These baseline data could be used to create a comprehensive national strategy of CWR conservation in Colombia
Evaluation of guajillo and chile de árbol peppers (Capsicum annuum L.) in a hydroponic greenhouse system
Objective: To evaluate the yield of guajillo pepper (CHG) and chile de árbol pepper (CHA) grown in containers with coconut fiber substrate in a hydroponic greenhouse system.Methodology: Four types of chili peppers were tested: two CHG and two CHA peppers. The CHG peppers with seeds were from two growing areas in the state of San Luis Potosí (SLP), located in the Altiplano Central (high plateau region) of Mexico: one from Las Colonias, Salinas, and the other from El Barril, Villa de Ramos. The CHA pepperswere obtained in Yahualica, Jalisco: one in El Salto Verde (CHA-SaltoVerde) and the other in El Faro (CHA-Faro). The chili peppers were established in a hydroponic system with two types of containers (pots (SHM) and slabs (SHB)), in both of which coconut fiber (coir) was used as a substrate. The experimental design was completelyrandomized with three repetitions and the comparison of means was made with the Tukey test (p<0.05).Results: Significant differences were observed between chile de árbol and guajillo peppers grown in SHM regarding the following variables: plant height and number of leaves, flowers, and peppers. Chile de árbol peppers recorded the highest values for the four variables. There were also significant differences between the chile de árbol and the guajillo peppers regarding the fresh weight and dry weight variables, but, in this case, the guajillo peppers had the highest values. The highest dry weight value (g plant -1 ) was obtained by CHG-Barril (1,094 g plant -1 ), followed by CHG-Colonias (866 g plant -1); meanwhile, the lowest values were recorded for CHA-Faro and CHA-SaltoVerde chile de árbol peppers (819 and 258 g plant -1 , respectively). The same pattern was observed in the SHB, with significant differences between the chile de árbol —which had the highest values— and guajillo peppers for the following variables: plant height, number ofleaves, flowers, and peppers. There were also significant differences in terms of fresh weight between chile de árbol and guajillo peppers, with the latter recording higher values. Finally, CHG-Colonias and CHA-SaltoVerde showed the highest dry weight values with 633 and 595 g plant -1 , respectively. Although there were no significant differences between them, there were significant differences with respect to CHG-Barril and CHA-Faro (524 and 483 g plant -1 , respectively).Study Limitations/Implications: The present study has no major limitations.Conclusions: In general, a better dry yield of chili pepper was obtained with guajillo peppers produced in a pot system. Hydroponic systems in pots and slabs, using a coir substrate, are an alternative in protected agriculture for the production of guajillo and chile de árbol peppers.
Photospheric Magnetic Fields of the Trailing Sunspots in Active Region NOAA 12396
The solar magnetic field is responsible for all aspects of solar activity.
Sunspots are the main manifestation of the ensuing solar activity. Combining
high-resolution and synoptic observations has the ambition to provide a
comprehensive description of the sunspot growth and decay processes. Active
region NOAA 12396 emerged on 2015 August 3 and was observed three days later
with the 1.5-meter GREGOR solar telescope on 2015 August 6. High-resolution
spectropolarimetric data from the GREGOR Infrared Spectrograph (GRIS) are
obtained in the photospheric Si I 1082.7 nm and Ca I 1083.9
nm lines, together with the chromospheric He I 1083.0 nm triplet.
These near-infrared spectropolarimetric observations were complemented by
synoptic line-of-sight magnetograms and continuum images of the Helioseismic
and Magnetic Imager (HMI) and EUV images of the Atmospheric Imaging Assembly
(AIA) on board the Solar Dynamics Observatory (SDO).Comment: 4 pages, 2 figures, to be published in "Solar Polarization Workshop
8", ASP Proceedings, Luca Belluzzi (eds.
Alteraciones en el sentido del olfato y del gusto en pacientes con enfermedad renal crónica, trasplante y diálisis y su asociación con el estado nutricional
Introducción: La insuficiencia renal crónica tiene alteraciones como lo son la anosmia y la disgeusia, estas ocasionadas por el incremento de toxinas urémicas, que se acompaña de un aumento del catabolismo, lo que incrementa la morbimortalidad. Estos pueden influir en la alimentación del paciente y por tanto en su estado nutricio. Objetivo: Analizar las evidencias encontradas en la literatura sobre la prevalencia, fisiopatología y tratamiento de la pérdida de gusto y olfato en pacientes con ERC, en HD, en DP y trasplantados renales y su asociación con el estado nutricional, para ello se inició una búsqueda en Pubmed, Scielo, Google académico, Published, Kydney Pediatric, Elsevier, Nutrición Hospitalaria, Society Kidney, Renut, American Society of Nephrology, Kidney Internationality con las siguientes palabras clave: Loss of kidney smell, Sense of taste, CDK, Kidney lost taste, sense of smell, nutritional status (para el idioma inglés), insuficiencia renal, pérdida del gusto, pérdida de sentidos, pérdida de olfato, estado de nutrición (para el idioma español).
Resultados: Se muestra la relación existente de la pérdida del olfato con el grado de insuficiencia renal y el grado de acumulación de toxinas urémicas. Respecto al gusto, se ha descrito disminución por déficit de zinc y eliminación de urea por medio de la saliva, por la percepción alterada en estos pacientes de hemodiálisis prevalentemente asociada de forma independiente con índices en déficits por el estado nutricional y teniendo una mayor mortalidad. Conclusiones: La pérdida del olfato, del gusto o ambas es una condición frecuente en los pacientes con insuficiencia renal crónica y contribuye al riesgo nutricional de estos pacientes.
Key words: Renal, sentido del olfato, diálisis, sentido del gusto, estado nutrici
Dietary, Cultural, and Pathogens-Related Selective Pressures Shaped Differential Adaptive Evolution among Native Mexican Populations
Native American genetic ancestry has been remarkably implicated with increased risk of diverse health issues in several Mexican populations, especially in relation to the dramatic changes in environmental, dietary, and cultural settings they have recently undergone. In particular, the effects of these ecological transitions and Westernization of lifestyles have been investigated so far predominantly on Mestizo individuals. Nevertheless, indigenous groups, rather than admixed Mexicans, have plausibly retained the highest proportions of genetic components shaped by natural selection in response to the ancient milieu experienced by Mexican ancestors during their pre-Columbian evolutionary history. These formerly adaptive variants have the potential to represent the genetic determinants of some biological traits that are peculiar to Mexican people, as well as a reservoir of loci with possible biomedical relevance. To test such a hypothesis, we used genome-wide genotype data to infer the unique adaptive evolution of Native Mexican groups selected as reasonable descendants of the main pre-Columbian Mexican civilizations. A combination of haplotype-based and gene-network analyses enabled us to detect genomic signatures ascribable to polygenic adaptive traits plausibly evolved by the main genetic clusters of Mexican indigenous populations to cope with local environmental and/or cultural conditions. Some of these adaptations were found to play a role in modulating the susceptibility/resistance of these groups to certain pathological conditions, thus providing new evidence that diverse selective pressures have contributed to shape the current biological and disease-risk patterns of present-day Native and Mestizo Mexican populations
Optimal Nitrogen Fertilization to Reach the Maximum Grain and Stover Yields of Maize (Zea mays L.): Tendency Modeling
Utilization of maize stover to the production of meat and milk and saving the grains for human consumption would be one strategy for the optimal usage of resources. Variance and tendency analyses were applied to find the optimal nitrogen (N) fertilization dose (0, 100, 145, 190, 240, and 290 kg/ha) for forage (F), stover (S), cob (C), and grain (G) yields, as well as the optimal grain-to-forage, cob-to-forage, and cob-to-stover ratios (G:F, C:F, and C:S, respectively). The study was performed in central Mexico (20.691389° N and −101.259722° W, 1740 m a.m.s.l.; Cwa (Köppen), 699 mm annual precipitation; alluvial soils). N-190 and N-240 improved the individual yields and ratios the most. Linear and quadratic models for CDM, GDM, and G:F ratio had coefficients of determination (R2) of 0.20–0.46 (p < 0.03). Cubic showed R2 = 0.30–0.72 (p < 0.02), and the best models were for CDM, GDM, and the G:F, C:F, and C:S DM ratios (R2 = 0.60–0.72; p < 0.0002). Neither SHB nor SDM negatively correlated with CDM or GDM (r = 0.23–0.48; p < 0.0001). Excess of N had negative effects on forage, stover, cobs, and grains yields, but optimal N fertilization increased the proportion of the G:F, C:F, and C:S ratios, as well as the SHB and SDM yields, without negative effects on grain production
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