Evaluando el estado de la biodiversidad: el caso de la avifauna de la Serranía de las Quinchas, Boyacá, Colombia

Mediante registros visuales y auditivos obtenidos durante recorridos extensivos, complementados por capturas con redes y grabaciones, realizamos un inventario de las aves en tres sitios de diferentes elevaciones y grados de transformación del paisaje en la Serranía de las Quinchas, en la región del Magdalena medio, Colombia. Se estimó el porcentaje de cobertura de los diferentes hábitats en cada sitio y la abundancia de las aves en cada uno, basado en la frecuencia de encuentros; elaboramos una clasificación ecológica de las aves, enfatizando sus grados de asociación con hábitats primarios vs. alterados o antropogénicos. Con 10-13 días de campo por sitio y la captura de 833 individuos en 1083 horas-red, registramos 308 especies de aves en el área. La forma de las curvas de acumulación de especies y las distribuciones de abundancias indican que los muestreos son comparables entre sitios. Las frecuencias y bundancias de las especies de diferentes categorías ecológicas mostraron concordancia con la representación de los diferentes hábitats en cada sitio; los dos sitios con extensiones mayores de bosque tenían mayor riqueza de especies. La mayoría de las especies más restringidas al bosque primario ocurrió en un solo sitio; las especies más generalistas en cuanto a la cobertura arbórea estaban presentes en promedio en más de dos; las especies más asociadas a áreas abiertas en un sitio (especialistas en cuanto a la elevación) o en los tres. En abril la mayoría de especies estaba en reproducción y fue la época más propicia para detecciones auditivas. El conjunto más grande de especies restringidas al bosque estaba entre los suboscines del suborden Furnarii, y puede servir como indicador del estado de conservación del bosque si se escogen las especies apropiadas, ya que las familias grandes incluyen a especies con diversos requisitos de hábitat. Fue notoria la ausencia o escasez de ciertos grupos sujetos a la cacería en los sitios con bosques en buen estado. La  presencia confirmada o posible de varias especies amenazadas hace que la Serranía de las Quinchas merezca consideración para medidas de protección, especialmente ante la falta de zonas de conservación en el valle del Magdalena, un centro importante de endemismo entre la avifauna colombiana.Using sight and auditory records made during extensive observations, supplemented by mist-net captures and tape recordings, we made an inventory of the birds of three sites differing in elevation and degree of human transformation of the landscape, in the Serranía de las Quinchas in the middle Magdalena valley of Colombia. We estimated per cent cover of different habitat types in each site and abundances of birds in each, based upon encounter frequencies, and developed an ecological classification of the birds that emphasized their degrees of association with primary, disturbed or manmade habitats. With 10-1 3 field days per site and a total of 833 birds captured in 1083 net-hours, we recorded a total of 308 species in the studv area. The form of the species accumulation curves and distributions of abundances indicated that the samples from the three sites were comparable. The numbers and abundances of species in different ecological categories varied in accord with the representation of the different habitat types between sites; the two sites with the largest extensions of primary forest had greater species richness. The majority of forest-restricted species occurred at a single site; on average, the most generalized species with respect to tree cover occured in two or more sites; and species of open habitats occurred in one site (elevation specialists) or all three. Most species were breeding in April, also the best month for auditory records. The suboscine passerines of the suborder Furnarii (antbirds, ovenbirds and allies) include the largest single group of forest- restricted species which could serve as an indicator of the state of conservation of forest habitat, provided the appropriate species are chosen - most families include species with diverse habitat requirements. The scarcity or absence of several groups subject to hunting pressure was noteworthy in an otherwise healthy forest avifauna. The known or suspected presence of several endangered species makes the Serranía de las Quinchas worthy of protection, especially given the lack of other conservation areas in the Magdalena valley, an important center of endemism of Colombian birds

Novel Foot Orthosis

Capstone Design and Manufacturing Experience: Fall 2006The objective of this design project is to implement a device capable of resting the posterior Thetibialis tendon (for less advanced stages of PTT), or (for more advanced cases) to perform the functions of the tendon by initiating heel inversion, while allowing full range of foot motion. The prototype is light-weight, durable and fits in a shoe. The PTTO can be improved by securing the leg cuff, using stronger and non-metallic components and minimizing protrusions on the medial side of the ankle. With these improvements the PTTO will be able to meet all engineering specifications. Thus the PTTO will be marketable, patentable and beneficial to patients with posterior tibilias tendonitis.http://deepblue.lib.umich.edu/bitstream/2027.42/49551/2/ME450 Final Team 22.pd

Observaciones sobre la composición, ecología, y zoogeografía de la avifauna de la Sierra de Chiribiquete, Caquetá, Colombia

Realizamos un inventario de la avifauna de una meseta en la Sierra de Chiribiquete, una serie de mesetas aisladas en la planicie amazónica del sureste colombiano, previamente sin exploraciones ornitológicas. Los hábitats del área de estudio incluyeron sabanas arbustivas y matorrales, y varios tipos de bosque. Se registraron un total de 77 especies para el sitio, y se colectaron 38 especímenes de 25 especies. Fueron notorias la poca diversidad y baja densidad de la avifauna, posiblemente relacionadas con la baja productividad y poca profundidad de los suelos arenosos del área. En general, el número de especies de aves en los distintos hábitats estuvo relacionado con la altura y diversidad estructural y taxonómica de la vegetación, con 20-40 especies en los diferentes tipos de bosques, y 13-16 especies en los sabanas y matorrales. Grupos tróficos bien representados en la avifauna fueron las rapaces, los consumidores de insectos pequeños, y (por lo menos en términos de número de especies), los nectarívoros; las aves frugívoras, granívoras, yacuáticas estuvieron muy pobremente representadas. Familias bien representadas incluyeron Formicariidae, Tyrannidae, y Trochilidae. La poca representación de familias de frugívoras grandes como Psittacidae, Ramphastidae, Cotingidae, etc., y de aves granívoras como Columbidae y Emberizidae, fue notoria. Los oscines en general estuvieron pobremente representados: 8 de las 21 especies registradas eran migrantes boreales. Se registró por primera vez en Colombia a Neomorphus rufipennis. La época reproductiva no habia comenzado aún para la gran mayoría de las especies; es posible que la disponibilidad de recursos, en particular de frutos, estaba en un punto bajo en el área. El grueso de la avifauna consiste de especies con afinidades cercanas con las aves de las sabanas y los bosques sobre suelos arenosos de la Orinoquía, y no con las de los bosques húmedos del piedemonte andino o de la Amazonia. Es probable que las distribuciones de estas aves eran más continuas durante los períodos secos del Pleistoceno, cuando las sabanas cubrían gran parte del sureste colombiano. En cambio, un número pequeño de especies parece haber arribado a la Sierra desde los Andes, o de los hábitats secos del alto Valle del Magdalena. Unicamente entre estas especies hay evidencia de una diferenciación taxonómica, dando como resultado formas endémicas a la Sierra de Chiribiquete.We report on an inventory of the avifauna of a mesa in the Sierra de Chlribiquete, a range of table-top mountains isolated in the Amazonian lowlands of SE Colombia, and previously unexplored ornithologically. Habitats in our study area included brushy savanna and scrub, and several types of forests. We recorded a total of 77 species, and collected 38 specimens representing 25 species. The avifauna of the study area was striking lor lts low density of individuals and low speeies diversity, probably related to the low productivity and poor nutrient content of the very shallow, sandy soil. In general, avian species richness per habitat was correlated with the height and structural and taxonomic diversity of the vegetation, with 20- 40 species in the different lorest habitats, and 13-16 species in savanna and scrub. Trophic groups well represented in the avifauna included small insectivores, raptores, and nectarivores (at least in terms of numbers of species); acuatic birds, frugivores and granivores were poorly represented. Families well represented included Formicariidae, Tyrannidae, and Trochilidae; few or no species of families of large frugivores like Psittacidae, Ramphastidae, or Cotingidae, or granivores like Columbidae or Emberizidae were recorded. The oscines in general were poorly represented, and no less than 8 of 21 species were boreal migrants. Neomorphus rufipennis was recorded for the first time in Colombia. For most species, the breeding season had not yet begun, and food resources, especially fruit, appeared to be scarce. The bulk of the avifauna shows close affinities with the birds of the savannas and sandy-belt forests of the Orinocan region, and not with the humid forest birdsof theAndean foothills or the Amazonian region. The distribution of these birds was probably more continuous during the Pleistocene, when savannas evidently covered much of SE Colombia. A small number of species have apparently dispersed to the Sierra from the Andes or the dry upper Magdalena Valley. Only among the latter is there evidence of taxonomic differentiation, resulting in forms endemic to the Sierra de Chiribiquete

Interacción planta-colibrí en amacayacu (Amazonas, Colombia): una perspectiva palinológica

From a palinological perspective was studied the plant-hummingbird relationship at community level, in the National Natural Park Amacayacu in the Colombian Amazonia. Our goal was to evaluate the utility ofthe palinological tool, to provided insight of the hummingbird-plant relationship organization, at community leve!. We get evidence about which plants were really using the hummingbirds as pollen vectors. A Resource Importance Value Index (RIVI) is proposed here to evaluate the importance of each floral resource to the hummingbird community. A binary correspondence analysis perrnitted us to proposed three groups ofplant-hummingbird associations, according with the frequency of pollen registered on each hummingbird species. The Relación colibrí-flor en una comunidad amazónica hummingbirds culmen morphology emerged as the explicative factor ofthe associations. The possible role ofthe reticulate pollen sculpture in the syndrome of ornithophily is discussed, as the restrictions and goodness of both methods: palynological and observational .Se cuantificaron 232 cargas de polen tomadas de 11 especies de colibríes en el Parque Nacional Natural Amacayacu, Amazonas, Colombia. Las especies más generalistas transportaron cargas de polen con mayor cantidad de granos. Las características palinológicas predominantes en los granos de polen sugieren una relación entre estructura reticulada y la polinización por colibríes. Se propone un Índice de Valor de Importancia de los Recursos (IVIR) orientado a estimar la importancia de cada una de las plantas ornitófilas para la comunidad de colibríes. Las plantas más importantes para los colibríes fueron: una especie de Heliconia, una especie de Passiflora, Besleria aggregata, una especie de Costus, ombretum llewelynii y Erythrina fusca. Con base en un análisis de correspondencia binaria se describen tres asociaciones plantacolibrí a nivel de comunidad, en las cuales la morfología del pico de los colibríes emerge como el aspecto explicativo de las asociaciones. Se analizan las ventajas y desventajas de las metodologías usadas por la palinología y por la observación directa en el campo

Primeros registros para Colombia de cuatro taxones de la familia tyrannidae (aves: passeriformes)

En esta comunicación presentamos datos sobre cuatro taxones de la familia Tyrannidae que representan registros nuevos para el territorio colombiano, todos respaldados con especímenes en la colección del Instituto de Ciencias Naturales (ICN). La mayoría de los registros son del campo petrolero de Caño Limón, a unos 55 km al occidente de la ciudad de Arauca, en la parte septentrional del Departamento de Arauca. Las características de este sitio y datos generales de su avifauna fueron presentados por McN ish and amp; Stiles (1992), Yun análisis detallado de la ecología y afinidades biogeográficas de esta avifauna fue realizado por Rojas and amp; Piragua (1992)

The transplant iron score as a predictor of stem cell transplant survival

Recent studies have suggested that the presence of iron overload prior to stem cell transplantation is associated with decreased survival. Within these studies, the criteria used to define iron overload have varied considerably. Given the lack of consensus regarding the definition of iron overload in the transplant setting, we sought to methodically examine iron status among transplant patients. We studied 78 consecutive patients at risk for transfusion-related iron overload (diagnoses included AML, ALL, MDS, and aplastic anemia) who received either autologous or allogeneic stem cell transplant. Multiple measures of iron status were collected prior to transplantation and examined for their association with survival. Using this data, three potentially prognostic iron measures were identified and incorporated into a rational and unified scoring system. The resulting Transplant Iron Score assigns a point for each of the following variables: (1) greater than 25 red cell units transfused prior to transplantation; (2) serum ferritin > 1000 ng/ml; and (3) a semi-quantitative bone marrow iron stain of 6+. In our cohort, the score (range 0 to 3) was more closely associated with survival than any available single iron parameter. In multivariate analysis, we observed an independent effect of iron overload on transplant survival (p = 0.01) primarily attributable to an increase in early treatment-related deaths (p = 0.02) and lethal infections. In subgroup analysis, the predictive power of the iron score was most pronounced among allogeneic transplant patients, where a high score (≥ 2) was associated with a 50% absolute decrease in survival at one year. In summary, our results lend further credence to the notion that iron overload prior to transplant is detrimental and suggest iron overload may predispose to a higher rate of lethal infections

Dopamine-modulated dynamic cell assemblies generated by the GABAergic striatal microcircuit

The striatum, the principal input structure of the basal ganglia, is crucial to both motor control and learning. It receives convergent input from all over the neocortex, hippocampal formation, amygdala and thalamus, and is the primary recipient of dopamine in the brain. Within the striatum is a GABAergic microcircuit that acts upon these inputs, formed by the dominant medium-spiny projection neurons (MSNs) and fast-spiking interneurons (FSIs). There has been little progress in understanding the computations it performs, hampered by the non-laminar structure that prevents identification of a repeating canonical microcircuit. We here begin the identification of potential dynamically-defined computational elements within the striatum. We construct a new three-dimensional model of the striatal microcircuit's connectivity, and instantiate this with our dopamine-modulated neuron models of the MSNs and FSIs. A new model of gap junctions between the FSIs is introduced and tuned to experimental data. We introduce a novel multiple spike-train analysis method, and apply this to the outputs of the model to find groups of synchronised neurons at multiple time-scales. We find that, with realistic in vivo background input, small assemblies of synchronised MSNs spontaneously appear, consistent with experimental observations, and that the number of assemblies and the time-scale of synchronisation is strongly dependent on the simulated concentration of dopamine. We also show that feed-forward inhibition from the FSIs counter-intuitively increases the firing rate of the MSNs. Such small cell assemblies forming spontaneously only in the absence of dopamine may contribute to motor control problems seen in humans and animals following a loss of dopamine cells. (C) 2009 Elsevier Ltd. All rights reserved

Hall effect measurements on YbRh2Si2 and relatives in the light of electronic structure calculations

We report experimental and theoretical investigations of the Hall effect in YbRh2Si2 and its reference compounds LuRh2Si2 and YbIr2Si2. Based on band-structure calculations we identify two bands dominating the Hall coefficient in all these compounds. For the case of LuRh2Si2 - the non-magnetic reference compound of YbRh2Si2 - the temperature dependence of the Hall coefficient is described quantitatively to arise from two hole-like bands. For YbIr2Si2 and YbRh2Si2, renormalized band calculations yield two bands of opposite character. In YbRh2Si2 these two bands almost compensate each other. We present strong indications that the sample dependences of the low-temperature Hall coefficient observed for YbRh2Si2 arise from slight variations of the relative scattering rates of the two bands. Minute changes of the composition appear to be the origin.Comment: 12 pages, 8 figure