Efectos mediados por hospedero en la variación del tamaño de frutos del muérdago hemiparásito Psittacanthus schiedeanus (Loranthaceae)

Background and Aims: Most fruits of Psittacanthus mistletoes (Loranthaceae) depend on frugivorous birds for seed dispersal, and their spatial distribution patterns within and between hosts are strongly influenced by the behavior of seed dispersers. Despite the importance of birds in their dispersal and distribution, the effects of host species on fruit size variation have not been investigated to any large extent. The aim of this study was to characterize fruit size variation of Psittacanthus schiedeanus ripe fruits growing on different host species. We expect that the fruit size traits will vary according to the quality of host species, and that this variation will correspond to those in mistletoe reproductive success. Methods: Fully ripe fruits from Psittacanthus schiedeanus mistletoe plants growing on different host tree species were collected at two locations (Tlalnelhuayocan and Coapexpan) of cloud forest in central Veracruz, Mexico, measured (length and width and length of cupular pedicels) and weighed to describe fruit size differences. Key results: Cupular pedicel length and fruit size were significantly affected by host species. On average, longest cupular pedicels and larger fruits were found on plants growing on naturally growing Acacia pennatula, Quercus germana, Ostrya virginiana and Liquidambar styraciflua, whereas the smaller ones were found generally on cultivated host trees. Conclusions: The results provide us with valuable information for further species comparisons regarding the effects of host species on fruit size variation. Although the effects of host species on fruit size variation might vary across space, fruit size differences might be the result of host-resource differences. Further study on fruit selection and fruit handling by seed dispersers is needed to discuss whether the observed fruit size variation correlates with fruit selection and handling by main consumers, and with successful attachment and establishment to host branch after gut passage.Antecedentes y Objetivos: La mayoría de los frutos de los muérdagos de Psittacanthus (Loranthaceae) para la dispersión de sus semillas dependen de las aves frugívoras, y el comportamiento de estos dispersores influye en sus patrones de distribución espacial dentro y entre hospederos. A pesar de la importancia de las aves en su dispersión y distribución, los efectos de la especie de hospedero en la variación del tamaño de los frutos no han sido investigados de manera extensa. El objetivo de este estudio fue caracterizar la variación del tamaño de los frutos maduros de Psittacanthus schiedeanus que crecen en diferentes especies de hospedero. Esperamos que los rasgos del tamaño de los frutos varíen de acuerdo con la calidad de la especie del hospedero, y que esta variación se corresponda con la del éxito reproductivo del muérdago. Métodos: Frutos maduros de plantas de muérdagos Psittacanthus schiedeanus creciendo en especies diferentes de árboles hospederos fueron colectados en dos sitios (Tlalnelhuayocan y Coapexpan) de bosque mesófilo de montaña en el centro de Veracruz, México, medidos (largo y ancho y largo de los pedicelos cupulares) y pesados para describir las diferencias en su tamaño. Resultados clave: La longitud del pedicelo cupular y el tamaño del fruto se vieron significativamente afectados por la especie de hospedero. En promedio, pedicelos cupulares más largos y frutos más grandes se encontraron en plantas que crecen en Acacia pennatula, Quercus germana, Ostrya virginiana y Liquidambar styraciflua, mientras que los más pequeños se encontraron generalmente en plantas sobre árboles hospederos cultivados. Conclusiones: Los resultados nos brindan información valiosa para futuras comparaciones entre especies en relación con los efectos de la especie de hospedero en la variación del tamaño de los frutos. Aunque los efectos de la especie de hospedero en la variación del tamaño de los frutos pueden variar en el espacio, las diferencias en el tamaño de los frutos pueden ser el resultado de diferencias en el recurso del hospedero. Se necesitan más estudios sobre la selección y el manejo de los frutos por parte de los dispersores de semillas, para discutir si la variación observada en el tamaño de los frutos se correlaciona con la selección y el manejo de los frutos por parte de los principales consumidores, y con la unión y el establecimiento exitosos en la rama del hospedero después del paso por el tracto intestinal

Selection and geographic isolation influence hummingbird speciation: genetic, acoustic and morphological divergence in the wedge-tailed sabrewing (Campylopterus curvipennis)

<p>Abstract</p> <p>Background</p> <p>Mesoamerica is one of the most threatened biodiversity hotspots in the world, yet we are far from understanding the geologic history and the processes driving population divergence and speciation for most endemic taxa. In species with highly differentiated populations selective and/or neutral factors can induce rapid changes to traits involved in mate choice, promoting reproductive isolation between allopatric populations that can eventually lead to speciation. We present the results of genetic differentiation, and explore drift and selection effects in promoting acoustic and morphological divergence among populations of <it>Campylopterus curvipennis</it>, a lekking hummingbird with an extraordinary vocal variability across Mesoamerica.</p> <p>Results</p> <p>Analyses of two mitochondrial genes and ten microsatellite loci genotyped for 160 individuals revealed the presence of three lineages with no contemporary gene flow: <it>C. c. curvipennis, C. c. excellens</it>, and <it>C. c. pampa </it>disjunctly distributed in the Sierra Madre Oriental, the Tuxtlas region and the Yucatan Peninsula, respectively. Sequence mtDNA and microsatellite data were congruent with two diversification events: an old vicariance event at the Isthmus of Tehuantepec (<it>c</it>. 1.4 Ma), and a more recent Pleistocene split, isolating populations in the Tuxtlas region. Hummingbirds of the <it>excellens </it>group were larger, and those of the <it>pampa </it>group had shorter bills, and lineages that have been isolated the longest shared fewer syllables and differed in spectral and temporal traits of a shared syllable. Coalescent simulations showed that fixation of song types has occurred faster than expected under neutrality but the null hypothesis that morphological divergence resulted from drift was not rejected.</p> <p>Conclusions</p> <p>Our phylogeographic analyses uncovered the presence of three Mesoamerican wedge-tailed sabrewing lineages, which diverged at different time scales. These results highlight the importance of the Isthmus of Tehuantepec and more recent Pleistocene climatic events in driving isolation and population divergence. Coalescent analyses of the evolution of phenotypic traits suggest that selection is driving song evolution in wedge-tailed sabrewings but drift could not be rejected as a possibility for morphological divergence.</p

Positioning system for 3D scans inside objects

En este trabajo presentamos un sistema de posicionamiento de visión activa para el escaneo 3D del interior de piezas. El diseño del sistema propuesto consta de dos módulos: un sistema de dimensionamiento 2D de visión activa, y un sistema que posiciona el módulo de visión activa. El sistema de posicionamiento es capaz de determinar la profundidad del sistema de dimensionamiento 2D de visión activa en el interior del objeto a escanear usando varios sensores. Las principales contribuciones de este trabajo son la caracterización del sistema de dimensionamiento 2D, y el desarrollo de algoritmos de posicionamiento de la luz activa con énfasis en el modelado y fusión de sensores. El sistema puede utilizarse como un sistema de dimensionamiento en aplicaciones industriales como la industria metal mecánica, la aeronáutica, la medicina, en el control de calidad y en áreas de visión por computadora.In this work we present an active positioning system for 3D scan of interior parts. The design of the proposed system consists of two modules: an active 2D dimensional system and positional system based on active vision. The active 2D dimensional system is able to determine the depth of the 2D dimensional system inside the object to be scanned using several sensors. The main contributions of this work are the characterization of the 2D dimensional system and the development of active light positioning algorithms with emphasis on the modeling and fusion of the sensors. The system can be used as a dimensional system in industrial applications such as the metal mechanical industry, aeronautics industry, medicine, quality control and computer vision.Peer Reviewe

Factorial Structure of the Self-Report of Barriers for Practice of Physical Exercise Among Mexican Non Athlete University Students

The present study intends to investigate if the psychometric results proposed by Niñerola, Capdevila and Pintanel (2006) for the Self-report of Barriers for Practice Physical Exercise (ABPEF) in Mexican university students are replicated. A total of 877 university students (mean age = 20.8 ± 2.5 years) participated. The factorial structure of the questionnaire was analyzed through confirmatory factorial analyzis, which showed that a four factor structure is feasible and adequate. The four factors (body image, fatigue, obligations and environment), according to statistical and substantive criteria, have shown adequate fit indicators of reliability and validity, which correspond to the structure proposed for the original questionnaire. In addition, the results of the factorial analyzis carried out with the subsamples, indicate the existence of strong evidence of the stability of the factorial structure. Further research should replicate these findings in larger samples

Factorial Structure of the Self-Report Barriers for Practice Physical Exercise in Mexican Athletes University Students

The present study intends to investigate if the psychometric results are replicated for the Self-Report of Barriers to the Practice of Physical Exercise (ABPEF) in Mexican athletes university students. A total of 651 university students participated (mean age = 20.8 ± 2.4 years). The factorial structure of the questionnaire was analyzed through confirmatory factor analyzes, which showed that a structure of four factors is viable and adequate. The four factors (body image, fatigue, obligations and environment), based on statistical and substantive criteria, have shown adequate fit indicators of reliability and validity. In addition, the results of the factorial analyzes carried out with the sub-samples indicate the existence of strong evidence of the stability of the factorial structure. Future research should replicate these findings in larger samples

Hand features extractor using hand contour – a case study

Hand gesture recognition is an important topic in natural user interfaces (NUI). Hand features extraction is the first step for hand gesture recognition. This work proposes a novel real time method for hand features recognition. In our framework we use three cameras and the hand region is extracted with the background subtraction method. Features like arm angle and fingers positions are calculated using Y variations in the vertical contour image. Wrist detection is obtained by calculating the bigger distance from a base line and the hand contour, giving the main features for the hand gesture recognition. Experiments on our own data-set of about 1800 images show that our method performs well and is highly efficient

Composición factorial del Multidimensional Body Self Relations Questionnaire (MBSRQ) en universitarios mexicanos

El presente estudio pretendió replicar los resultados psicométricos propuestos por Botella, Ribas y Ruiz para la versión española del Multidimensional Body Self Relations Questionnaire en una muestra de universitarios mexicanos. Participaron un total de 1539 universitarios con una edad media de 20.56 años (DE=1.88). La estructura del cuestionario se analizó a través de análisis factoriales exploratorios y confirmatorios. Los resultados mostraron que una estructura de dos factores (importancia subjetiva de la apariencia física e importancia subjetiva de la forma física) es viable y adecuada. Esta estructura atendió a criterios estadísticos y sustantivos, mostrando adecuados indicadores de ajuste de fiabilidad y validez. Sin embargo, el modelo obtenido no coincide con el planteado por Botellay colaboradores. Futuras investigaciones deberían replicar estos hallazgos en muestras más amplias.The aim of this study was to analyze if psychometric results proposed by Botella, Ribas and Ruiz for the Spanish version of the Multidimensional Body Self Relations Questionnaire could be replicated in Mexican university students. A total of 1539 university students participated in this study with a mean age of 20.56 years (SD = 1.88). The factor structure of the questionnaire was analyzed trough exploratory and confirmatory factor analyses. Results showed a feasible and adequate structure of two factors (subjective importance of the physical appearance and subjective importance of the physical shape), with adequate fit indices of reliability and validity, according to statistical and substantive criteria. However, the obtained model does not coincide with that proposed by Botella et al. Future research should replicate these findings in wider samples.O presente estudo pretendeu replicar os resultados psicométricos propostos por Botella, Ribas e Ruiz para a versão espanhola do Multidimensional Body Self Relations Questionnaire em uma amostra de universitários mexicanos. Participaram um total de 1539 universitários com uma idade média de 20,56 anos (DP = 1,88). A estrutura do questionário analisou-se através de análisesfatoriais exploratórios e confirmatórios. Osresultados mostraram que uma estrutura de doisfatores(importância subjetiva da aparência física e importância subjetiva da forma física) é viável e adequada. Esta estrutura atendeu a critérios estadísticos y substantivos, mostrando adequados indicadores de ajuste de fiabilidade e validez. Porém, o modelo obtendo no coincide com o apresentado por Botella et al. Futuras investigações deveriam replicar estos achados em amostras mais grande

Composición e invarianza factorial del cuestionario Medida de la Intencionalidad para ser Físicamente Activo (MIFA) en adolescentes mexicanos

The aim of this research was to analyze the psychometric properties proposed by Moreno et al. (2007) for the Measurement of Intention to be Physically Active (MIFA) questionnaire. The total sample has been composed by 549 Mexican adolescents, 256 women and 293 mean, with ages from 11 to 16 years (M = 12.91, SD = 0.49). The factor structure of questionnaire has been analized through the confirmatory factor analysis. This analysis shows that a unifactorial structure is viable and adequate for the total sample and the populations of men and women. The unifactorial structure, according to statistical and substantive criteria, has shown adequate indicators of reliability and validity adjustment. On the other hand, the factorial structure, the factorial loads and the intercepts are considered invariant according to gender; however, there are differences between men and women for the average intentionality of being physically active. In conclusion, the MIFA-M can be a useful tool to advance in the study of the factors that affect the practice of physical activity.El objetivo de esta investigación fue analizar las propiedades psicométricas propuestos por Moreno, Moreno y Cervelló (2007) para el cuestionario Medida de la Intencionalidad para ser Físicamente Activo (MIFA). La muestra total fue de 549 adolescentes mexicanos 256 mujeres y 293 hombres, con edades comprendidas entre 11-16 años (M = 12.91; DE = 0.49). La estructura factorial del cuestionario se analizó mediante análisis factoriales confirmatorios. Los análisis, muestran que una estructura unifactorial es viable y adecuada tanto para la muestra total como para las poblaciones de hombres y mujeres. La estructura unifactorial, atendiendo a criterios estadísticos y sustantivos, ha mostrado adecuados indicadores de ajuste de fiabilidad y validez. Por otro lado, la estructura factorial, las cargas factoriales y los interceptos se consideran invariantes de acuerdo al género; sin embargo, existen diferencias entre hombres y mujeres para la media de intencionalidad para ser físicamente activo. En conclusión, el MIFA-M puede ser una herramienta útil para avanzar en el estudio de los factores que afectan a la práctica de actividad física.O objetivo do presente estudo instrumental foi analisar a composição e invariância fatorial por gênero do questionário Medida de Intencionalidade a ser Fisicamente Ativa proposto por Moreno et al. (2007) adaptado ao contexto mexicano (MIFA-M) em adolescentes mexicanos. Um total de 549 adolescentes mexicanos, 256 mulheres e 293 homens, com idades entre 11 e 16 anos (M = 12.91; DP = .49) completaram o questionário MIFA-M. A estrutura fatorial do questionário foi analisada por análises fatoriais confirmatórias. Os resultados mostraram que uma estrutura unifatorial é viável e adequada tanto para a amostra total quanto para as populações de homens e mulheres. Com base em critérios estatísticos e substantivos, a estrutura unifatorial apresentou indicadores adequados de confiabilidade e validade. Além disso, a estrutura fatorial, as cargas fatoriais e os interceptos eram invariantes de acordo com o gênero. Maiores valores de intenção de ser fisicamente ativo em homens do que em mulheres foram encontrados. Maiores valores de intenção de ser fisicamente ativo em homens do que em mulheres foram encontrados. Em conclusão, o MIFA-M é um instrumento útil para avaliar a intenção de ser fisicamente ativo em adolescentes mexicanos

A mistletoe tale: postglacial invasion of Psittacanthus schiedeanus (Loranthaceae) to Mesoamerican cloud forests revealed by molecular data and species distribution modeling

Map showing collecting sites of Psittacanthus schiedeanus. Numbers refer to collection sites and thin ellipses show collecting sites within the cloud forest areas. Region abbreviations are as follows: nSMO northern Sierra Madre Oriental, cSMO central Sierra Madre Oriental, sSMO southern Sierra Madre Oriental, CHIS Chiapan Highlands (cCHIS and pCHIS) separated by the Central Depression that together with Guatemala form the region Trans-Isthmian Highlands (TIH), OAX Oaxacan drylands. (PDF 5098 kb