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RELATIONSHIPS BETWEEN NUTRIENT ENRICHMENT AND THE PHYTOPLANKTON COMMUNITY AT AN ANDEAN OLIGOTROPHIC LAKE: A MULTIVARIATE ASSESSMENT
Francisco E. Fontúrbel,Gabriel J. Castao-Villa
Ecología Aplicada , 2011,
Abstract: El fitoplancton es uno de los componentes más sensibles a las condiciones eutróficas, y su perturbación puede tener potenciales efectos negativos de tipo bottom-up en los ecosistemas lénticos. En este trabajo se empleó una aproximación estadística multivariante (Análisis de Correspondencia Canónica, con una prueba por permutaciones de Monte Carlo) para examinar las relaciones entre el enriquecimiento de nutrientes y la diversidad de la comunidad de fitoplancton. Se muestrearon cuatro localidades con distinto grado de eutrofización en el sector boliviano del lago Titikaka. La diversidad de fitoplancton encontrada varió entre ocho y 16 géneros, cambiando significativamente entre los sitios de muestreo, estando la diversidad del fitoplancton significativamente correlacionada con el nitrógeno, el fósforo y el pH (prueba de Monte Carlo, p < 0,05). El fósforo fue identificado como el nutriente limitante en el ecosistema. La evaluación de la estructura de la comunidad mostró una distribución no agregada, y el análisis BDG resultó en una distribución de serie logarítmica, sugiriendo la partición no aleatoria del nicho. La aproximación metodológica empleada aquí permitió una evaluación rápida del efecto del enriquecimiento de nutrientes, considerando al fitoplancton y los nutrientes como un todo, siendo esta aproximación más poderosa que estudiar relaciones individuales mediante técnicas univariadas.
Extinciones locales de aves en fragmentos de bosque en la región de Santa Elena, Andes Centrales, Colombia
Castao-Villa,Gabriel J.; Pati?o-Zabala,Juan C.;
El hornero , 2008,
Abstract: we compared historic records from 1879 until 1952 of birds of santa elena region (colombian central andes) with those from a recent survey in three forest fragments of 41, 129 and 136 ha. only 64 out of the 132 original species still remain in the three fragments; 78%, 66% and 63% of the original species have disappeared from the fragments. species with high habitat specificity, those with body mass of 51-100 g, those which forage in the arboreal stratum, and those which forage on trunks showed a tendency to suffer more extinctions than expected. however, there were no statistical differences between observed and expected proportions of extinctions in any of the categories (trophic guild, foraging stratum, body mass and habitat specificity), indicating that all the bird groups presented the same vulnerability to extinction. mean body mass of extinct birds was similar to that of the birds still remaining in the fragments. species from the families grallaridae, cotingidae, thraupidae, trogonidae and from the subfamily dendrocolaptinae were the most affected. we discuss why the evaluated ecological features could not be related with local extinction of bird species in these forest fragments.
COMPOSICIóN DE LA COMUNIDAD DE AVES EN BOSQUES FRAGMENTADOS EN LA REGIóN DE SANTA ELENA, ANDES CENTRALES COLOMBIANOS
Castao-Villa,Gabriel Jaime; Pati?o-Zabala,Juan Camilo;
Boletín Científico. Centro de Museos. Museo de Historia Natural , 2007,
Abstract: the bird communities in three disturbed fragments in the central colombian andes santa elena region were compared and related in order to establish their role for avifauna conservation in this area. there were registered a total of 28, 46 and 49 species in the fragment i (41 ha), ii (129 ha) and iii (136 ha) respectively. bird abundance differed among the fragments and it was detected a low similarity between communities at species, trophic, body size, and foraging strata levels. it is concluded that areas selection for avifauna conservation at this locality must included different size of fragment, surrounding matrix, end perturbation history in order to accomplish with representation and complementarily criteria.
TENDENCIAS POBLACIONALES EN ALGUNAS ESPECIES DE AVES ACUáTICAS EN LA LAGUNA DEL OTúN ENTRE 1998 Y 2007
Gil-Ospina,Raul Fernando; Bedoya-Zuluaga,Felipe Alberto; Castao-Villa,Gabriel Jaime;
Boletín Científico. Centro de Museos. Museo de Historia Natural , 2010,
Abstract: based on census conducted in 1998, 2000 and 2007 to anas flavirostris, oxyura jamaicensis and fulica sp. (coots) in the el otún lake (colombian central andes), the trends of population size of these species were described. it was determined that the populations of o. jamaicensis and coots were reduced between 1998 and 2007 in a 63 and 54% respectively, and that the variations in the lake level during 2000 were correlated with the changes in the abundance of a. flavirostris. the results suggest that these species change in abundance both intra and inter annually and that they could be related with environmental variations. on the other hand, some disturbances (the fire occurred in 2006) could have affected the state of these populations reducing them even more. it is a priority to continue with the population monitoring of these species because of their reduced population size which makes them more vulnerable to stochastic environmental and demographic factors.
BANCO DE SEMILLAS DEL SUELO Y SU PAPEL EN LA RECUPERACIóN DE LOS BOSQUES TROPICALES
Bedoya-Pati?o,Juan G; Estévez-Varón,Jaime V; Castao-Villa,Gabriel J;
Boletín Científico. Centro de Museos. Museo de Historia Natural , 2010,
Abstract: given the high rates of deforestation of tropical forests and their effects on biological diversity among others, the recovery of the vegetable coverage is a task that must be undertaken immediately. therefore, knowing the factors which determine the natural growth of vegetation allows the planning and better direction of restoration efforts. in this sense, the study of the soil seeds bank provides information about the vegetal succession state, the species potentially capable to substitute the existing ones, and the types of species which compose the present and surrounding vegetation, as well as its relation with the wild fauna. this article presents a description of the meaning and importance of the seeds bank in the tropics, of the determinant factors for its existence, and of its contribution to restoration and conservation. also, some aspects related to the seeds bank for future research such as tropical seeds physiology and the role of animals which contribute to seed dispersal are stated.
DETERMINACIóN DEL SEXO EN AVES DE LA FAMILIA FURNARIDAE A TRAVéS DE TéCNICAS MOLECULARES
Moreno López,Daniel; Henao Bustamante,Beatriz Eugenia; López Gartner,Germán Ariel; Castao-Villa,Gabriel Jaime; Rivera Páez,Fredy Arvey;
Boletín Científico. Centro de Museos. Museo de Historia Natural , 2011,
Abstract: the furnariidae family is one of the most diverse groups of birds in the neotropics, and it is considered as a vulnerable to habitat disturbance group. the sexing of individuals in this family is complex due the lack of clear sexual dimorphism which limits the research in population dynamics and evolutionary studies. in this study, the dna was extracted from the quill of the feathers using the phenol-chloroform-isoamyl alcohol method in 15 furnarids species captured in four localities from the department of caldas between august 2009 and march 2010. the pcr amplification of chd-z and chd-w genes with primers p2-p8 and 2550f-2718r, allowed the differentiation of males from females of seven species (synallaxis azarae, s. brachyura, xenops minutus, dendrocincla tyrannina, lepidocolaptes lacrymiger, campylorhampus trochilirostris, c. pusillus), from which there was not previous report of molecular sexing. the efficiency of the source for dna extraction (80.65%) from feathers as a non-invasive, easy to use, handle and storage method that can be used in population dynamics, genetic structure, reproductive systems and behavioral studies, and in a wider way, in the management and conservation of this family was demonstrated.
APORTES DE UNA PLANTACIóN FORESTAL MIXTA A LA CONSERVACIóN DE LA AVIFAUNA EN EL CA?óN DEL RíO CAUCA, COLOMBIA
Castao Villa,Gabriel Jaime; Morales Betancourt,Juan Alejandro;
Revista Facultad Nacional de Agronomía, Medellín , 2008,
Abstract: the avifauna of a forest mixed plantation at cauca river canyon in caldas department; was monitored during 10 months. fifty nine understory resident species were captured, 10% of them presented high sensibility to habitat perturbation (forest specialists). only those species with low sensibility (generalists) presented differences between monthly numbers of captures. other 50 species associated to the plantation, including two endemics and 26% boreal migratory species were registered visually and/or by its vocalizations. the results suggest that this plantation plays a key role in the conservation of local avifauna, is habitat both for species associated with natural forests and for those with less habitat requirements. this type of reforestation with native species could be a restoration model for other degraded areas from the region.
APORTES DE UNA PLANTACIóN FORESTAL MIXTA A LA CONSERVACIóN DE LA AVIFAUNA EN EL CA óN DEL RíO CAUCA, COLOMBIA CONTRIBUTION OF A MIXED FOREST PLANTATION TO AVIFAUNA CONSERVATION AT RIO CAUCA CANYON, COLOMBIA
Gabriel Jaime Castao Villa,Juan Alejandro Morales Betancourt
Revista Facultad Nacional de Agronomía, Medellín , 2008,
Abstract: Se monitoreó la avifauna asociada al sotobosque de una plantación forestal mixta en el ca ón del río Cauca en el departamento de Caldas durante 10 meses. Se capturaron 59 especies residentes, de las cuales el 10% presentan una alta sensibilidad a la perturbación del bosque (especialistas de este tipo de hábitat). únicamente se presentaron diferencias entre el número mensual de capturas en aquellas especies con baja sensibilidad (generalistas). Además, se registraron otras 50 especies asociadas a la plantación, de las cuales dos son endémicas y el 26% migratorias boreales. Los resultados sugieren que esta plantación juega un papel clave en la conservación de la avifauna local, es hábitat tanto para especies asociadas a bosques naturales como para aquellas con menores requerimientos de hábitat. Este tipo de reforestación con especies nativas, podría ser tomado como un modelo de restauración de otras áreas degradadas de la región. The avifauna of a forest mixed plantation at Cauca river canyon in Caldas department; was monitored during 10 months. Fifty nine understory resident species were captured, 10% of them presented high sensibility to habitat perturbation (forest specialists). Only those species with low sensibility (generalists) presented differences between monthly numbers of captures. Other 50 species associated to the plantation, including two endemics and 26% boreal migratory species were registered visually and/or by its vocalizations. The results suggest that this plantation plays a key role in the conservation of local avifauna, is habitat both for species associated with natural forests and for those with less habitat requirements. This type of reforestation with native species could be a restoration model for other degraded areas from the region.
REMODELADO ESTRUCTURAL Y DE GAP JUNCTIONS EN UN MODELO 3D DE AURíCULA HUMANA
Ruiz-Villa,Carlos A.; Castao Vélez,Andrés P.; Heidenreich,Elvio A.;
Biosalud , 2011,
Abstract: introduction: atrial fibrillation (af) is the most common sustained cardiac arrhythmia and a significant risk factor for cerebrovascular accident and other morbidities if left untreated. epidemiological studies show that af tends to persist over time, creating electrophysiological and anatomical changes called atrial remodeling. it has been shown that these changes result in variations in conduction velocity (cv) in the atrial tissue. objective: to study the effect of remodeling of gap junctions in the propagation of the action potential by implementing a highly realistic 3d human atrial model. materials and methods: the changes caused by electrical remodeling were incorporated in an atrial myocyte action potential (ap) model coupled with an anatomically realistic three-dimensional model of dilated human atria. through simulations of the ap spread in variations of anatomical and electrical remodeling and of gap junctions remodeling, vulnerable windows of reentry generation were measured at the base of the atrium left pulmonary veins. results: the results obtained indicate that vulnerable window in the gap junctions remodeling moved 38 ms in relation with the expanded model which shows the impact of the dilatation gap junction remodeling. conclusions: the electrical remodeling produced 70% decrease in action potential duration and decreased conduction velocities between 14.6 and 26 %, which were measured in different regions of the dilated atrium. the focus shot at the base of the left pulmonary veins created a wave which maintains a reentering activity due to the underlying anatomy of the pulmonary veins.
Comportamiento ciudadano organizacional y RSE
Arredondo Trapero,Florina Guadalupe; Rosas Ferrer,José Antonio; Villa Castao,Lida Esperanza;
Cuadernos de Administración , 2011,
Abstract: there is an analysis of the citizenship behaviour of workers who take part in voluntary work projects promoted by their company as part of its corporate social responsibility. there is an evaluation of whether this participation develops attitudes in the workers involved which are different from those of workers who do not participate in this kind of projects. the research was conducted in a mexican food business that pursues csr projects in the contexts of community, environment and quality of life at work; it found that those who took part in the voluntary work show signs of civic awareness the benefit the organization as a whole and further, help to achieve the specific objectives of their project.
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