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Una población relicta de Acer saccharum subsp. skutchii (Aceroideae) en el estado de Guerrero, México
Yalma L. Vargas-Rodriguez
Acta botánica mexicana , 2011,
Abstract: Se describe la estructura, composición, diversidad, relaciones ambientales y conservación de un bosque mesófilo con Acer saccharum subsp. skutchii (arce azucarero) recientemente encontrado en el municipio de Coahuayutla de José María Izazaga, Guerrero. Se registraron los individuos le osos con >1 cm dap en parcelas circulares de 10 m de radio, y la altura de plántulas y plantas juveniles del arce azucarero en parcelas de 5.6 m de radio. Para cada especie se obtuvo su valor de importancia. Se utilizó la técnica de ordenación Escalar Multidimensional No-métrica (NMDS) para explorar sus correlaciones con variables edafológicas, coordenadas geográficas, de elevación y apertura de claros. Se registraron 43 especies de plantas le osas en una superficie de 0.126 ha. Las familias mejor representadas fueron Asteraceae y Fagaceae. La distribución diamétrica de las plantas le osas mostró una forma de "J" invertida, indicando regeneración exitosa. El arce azucarero fue codominante en el dosel con Carpinus caroliniana y Quercus uxoris. Tanto en la población de Guerrero, como en las otras cinco localidades donde habita el árbol en México y Guatemala, la mayoría de las correlaciones encontradas entre la presencia y ausencia de árboles, incluyendo Acer saccharum subsp. skutchii, y los factores ambientales se refirieron a las características de suelo. De las especies registradas en el estudio, 30% están incluidas en alguna categoría de riesgo. El régimen de incendios en la zona pone en peligro la persistencia de este árbol en el sitio de estudio.
Una población relicta de Acer saccharum subsp. skutchii (Aceroideae) en el estado de Guerrero, México
Vargas-Rodríguez, Yalma L;
Acta botánica mexicana , 2011,
Abstract: structure, composition, diversity, environmental relationships, and conservation status of a cloud forest with acer saccharum subsp. skutchii (sugar maple) are described in a recently found locality at coahuayutla de josé maría izazaga municipality, state of guerrero, mexico. woody individuals ≥1 cm dbh in 10 m/radius circular plots and seedlings and saplings heights of sugar maple in 5.6 m/radius circular plots were recorded. the relative ecological importance of each species was expressed in an importance value. non-metric multidimensional scaling (nmds) ordination technique was used to explore the species correlations with edaphic, geographic coordinates, elevation, and canopy gaps variables. 43 woody species in 0.126 ha were recorded. the families with most species were asteraceae and fagaceae. the diametric distribution of woody species showed an inverted "j" shape, indicating successful regeneration. sugar maple is co-dominant with carpinus caroliniana and quercus uxoris. most correlations between presence-absence of trees, including acer saccharum subsp. skutchii, were with soil characteristics in the population of guerrero and all maple localities in mexico and guatemala. 30% of the reported species are included in some risk category. the fire regime in the zone is a major threat for the persistence of the studied species.
Small-scale environmental gradients in a pine-oak forest community in Nueva Colonia, Mezquitic, Jalisco, Mexico
Nieves-Hernández, Gregorio;Vázquez-García, J. Antonio;Vargas-Rodriguez, Yalma L.;Vázquez-García, Marcelino;González-Gallegos, Jesús;
Polibotánica , 2009,
Abstract: we explored environmental variables related to pine-oak forest community structure at one locality in jalisco, mexico. we used an nms ordination in conjunction with the s？rensen distance to identify the major small-scale community gradients along 25 contiguous quadrats (25 m x 25 m, 400 m2 each) of pine-oak forest in nueva colonia, mezquitic, jalisco, mexico. the main matrix (25 stands x 7 tree species) included basal area data, and the environmental matrix consisted of 19 quantitative environmental variables. community structure, through sociological ordination, showed a direct correlation with the vertical altitudinal gradient and apparent soil density, as well as with slope inclination across the horizontal gradient; it also showed an inverse correlation with cation exchange capacity, ca + mg, mg, and altitude across the horizontal gradient. direct gradient analyses showed an increase of cation exchange capacity, ca+mg, mg and k with decreasing altitude along the vertical gradient (from north to south). total nitrogen increased with decreasing altitude across the horizontal gradient (from west to east). in addition, we identified three main community groups using upgma cluster analysis; however, groups were weakly related to the ordination results and to the physical space. at the 1-hectare scale, species composition and basal area of pine-oak forest in nueva colonia can be explained by niche partitioning of altitude and soil gradients. the relevance of nitrogen for this community could be the result of habitat specialization or disturbance history.
Juanulloa mexicana (Solanaceae), nuevo registro en el occidente de México
Yalma Luisa Vargas Rodríguez,Miguel de Jesús Cházaro Basá？ez,José Antonio Vázquez García
Boletín de la Sociedad Botánica de México , 2006,
Abstract:
Effect of Potassium Concentration on Some Agrophysiological Parameters of Pineapple Plants (Ananas comosus L. cv. Smooth Cayenne and MD2) Grown in C？te d'Ivoire
L.
- , 2018, DOI: 10.9734/JEAI/2018/45079
Abstract: (1) Dr. Slawomir Borek, Professor, Department of Plant Physiology, Adam Mickiewicz University, Poland.
Computing Reachable Sets as Capture-Viability Kernels in Reverse Time  [PDF]
No？l Bonneuil
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.311219
Abstract: The set SF(x0;T) of states y reachable from a given state x0 at time T under a set-valued dynamic x’(t)∈F(x (t)) and under constraints x(t)∈K where K is a closed set, is also the capture-viability kernel of x0 at T in reverse time of the target {x0} while remaining in K. In dimension up to three, Saint-Pierre’s viability algorithm is well-adapted; for higher dimensions, Bonneuil’s viability algorithm is better suited. It is used on a large-dimensional example.
Three Dimensional Evolution of SN 1987A in a Self-Gravitating Disk  [PDF]
L. Zaninetti
International Journal of Astronomy and Astrophysics (IJAA) , 2013, DOI: 10.4236/ijaa.2013.32010
Abstract:

The introduction of an exponential or power law gradient in the interstellar medium (ISM) allows to produce an asymmetric evolution of the supernova remnant (SNR) when the framework of the thin layer approximation is adopted. Unfortunately both the exponential and power law gradients for the ISM do not have a well defined physical meaning. The physics conversely is well represented by an isothermal self-gravitating disk of particles whose velocity is everywhere Maxwellian. We derived a law of motion in the framework of the thin layer approximation with a control parameter of the swept mass. The photon’s losses, which are often neglected in the thin layer approximation, are modeled trough velocity dependence. The developed framework is applied to SNR 1987A and the three observed rings are simulated.

The Luminosity Function of Galaxies as Modeled by a Left Truncated Beta Distribution  [PDF]
L. Zaninetti
International Journal of Astronomy and Astrophysics (IJAA) , 2014, DOI: 10.4236/ijaa.2014.41013
Abstract: A first new luminosity function of galaxies can be built starting from a left truncated beta probability density function, which is characterized by four parameters. In the astrophysical conversion, the number of parameters increases by one, due to the addition of the overall density of galaxies. A second new galaxy luminosity function is built starting from a left truncated beta probability for the mass of galaxies once a simple nonlinear relationship between mass and luminosity is assumed; in this case the number of parameters is six because the overall density of galaxies and a parameter that regulates mass and luminosity are added. The two new galaxy luminosity functions with finite boundaries were tested on the Sloan Digital Sky Survey (SDSS) in five different bands; the results produce a “better fit” than the Schechter luminosity function in two of the five bands considered. A modified Schechter luminosity function with four parameters has been also analyzed.
Evolution in Diagnosis and Classification of Diabetes  [PDF]
L. Sreenivasamurthy
Journal of Diabetes Mellitus (JDM) , 2021, DOI: 10.4236/jdm.2021.115017
Abstract: Diabetes, has been known to mankind for centuries, often described by its unique nature of sweet tasting urine or by the symptoms of excessive urination and thirst. Several renowned scientists have attempted to describe the symptoms, pathophysiology, diagnosis and various experimental treatment options with varying degrees of success. The current widely accepted classification focuses on etiology and pathogenesis to guide treatment and is very successful and adapted across the world. Diagnostic criteria underwent multiple changes to define glycemic targets which were more and more guided by better understanding of the disease pathogenesis. Recent research focuses on a more individualized approach to managing diabetes, better understanding and identifying individuals who are at an increased risk of complications at diagnosis itself to offer more personalized management to prevent long term complications. Early differentiation of individual based on multiple factors rather than a single parameter is the path being paved currently. BMI, Waist circumference, age at diagnosis, HbA1c, triglycerides, HDL cholesterol, GAD Antibodies, Homeostasis model assessment of Insulin Resistance (HOMA-2 IR), beta-cell dysfunction (HOMA2-Beta), and fasting and stimulated C-peptide, are core parameters in the current rationalized approach towards better long term outcomes for people with diabetes. Cluster based identification and focused treatment with individualistic targets is the way forward in Diabetes management.
On the Dark Matter’s Halo Theoretical Description  [PDF]
L. M. L. M. Chechin
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.35052
Abstract: We argued that the standard field scalar potential couldn’t be widely used for getting the adequate galaxies’ curve lines and determining the profiles of dark matter their halo. For discovering the global properties of scalar fields that can describe the observable characteristics of dark matter on the cosmological space and time scales, we propose the simplest form of central symmetric potential celestial-mechanical type, i.e. U(φ) = –μ/φ. It was shown that this potential allows get rather satisfactorily dark matter profiles and rotational curves lines for dwarf galaxies. The good agreement with some previous results, based on the N-body simulation method, was pointed out. A new possibility of dwarf galaxies’ masses estimation was given, also.
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