2,725 research outputs found

    Neotropical tadpoles: spatial and temporal distribution and habitat use in a seasonal lake in Veracruz, México

    Get PDF
    We studied a tadpole assemblage in a seasonal neotropical lake where 14 species of anurans reproduce. Tadpoles were collected monthly at nine sampling stations at depth intervals of 1 m from the surface to the bottom (13 m). Sufficient numbers of tadpoles of three species were collected to compare habitat use. This three species assemblage breed in the following order (first to last): Smilisca baudinii, Gastrophryne usta, and Rana berlandieri. R. berlandieri had the greatest microhabitat breadth followed by S. baudinii. S. baudinii and G. usta had high microhabitat overlap, but significant differences in microhabitat use were found. S. baudinii tended to occur near the bottom, while G. usta was near the surface. This study shows that temporal and habitat partitioning both occur and depend on the species of tadpole. Dynamic interactions occur between habitat and temporal dimensions. Phenology and habitat selection depend both on the species and on abiotic and biotic factors

    Editorial

    Get PDF

    Neuromuscular and acute symptoms responses to progressive elastic resistance exercise in patients with chronic obstructive pulmonary disease:Cross-sectional study

    Get PDF
    BACKGROUND: Quadriceps muscle training is a key part in the rehabilitation of chronic obstructive pulmonary disease (COPD) patients. However, exercise intensity prescription and progression with the typically used elastic bands is challenging. We aimed to evaluate neuromuscular, acute symptoms and cardiorespiratory responses (heart rate and dyspnea) during progressive elastic resistance exercise in patients with COPD. METHODS: Fourteen patients diagnosed with moderate-very severe COPD performed knee extensions at different elastic resistance levels (i.e., colors). The neuromuscular activity was recorded using surface electromyography for the rectus femoris, vastus lateralis and vastus medialis, together with rate of perceived exertion, perceived quadriceps fatigue, dyspnea, oxygen saturation and heart rate. RESULTS: For the vastus lateralis and rectus femoris, increase of muscle activity was evident from a two-level increment when using the red color. For the vastus medialis, there were no muscle activity progressions. Dyspnea, quadriceps fatigue and especially rate of perceived exertion increased in a dose-response fashion and were correlated with the resistance level and muscle activity at the three muscles. CONCLUSION: Heavy elastic resistance exercise is feasible in COPD patients without excessive dyspnea and a stable cardiorespiratory response. In general, at least two elastic resistance increments are needed to enhance muscle activity for the vastus lateralis and rectus femoris, while there is no increase for the vastus medialis. These results may help to individualize exercise dosing during elastic resistance training in patients with COPD

    Evaluation of Wearable Sensor Tag Data Segmentation Approaches for Real Time Activity Classification in Elderly

    Get PDF
    Abstract. The development of human activity monitoring has allowed the creation of multiple applications, among them is the recognition of high falls risk activities of older people for the mitigation of falls occurrences. In this study, we apply a graphical model based classification technique(conditional random field) to evaluate various sliding window based techniques for the real time prediction of activities in older subjects wearing a passive (batteryless) sensor enabled RFID tag. The system achieved maximum overall real time activity prediction accuracy of 95% using a time weighted windowing technique to aggregate contextual information to input sensor data

    Rotavirus grupo A en lechones lactantes en una granja porcina convencional.

    Get PDF
    En una piara de manejo convencional semintensiva se estudiaron 9 camadas en el transcurso de 10 meses del año. Durante este lapso el 87 por ciento de los lechones de 8 de las camadas presentaron diarrea de variada intensidad y características. La mortalidad varió entre 5 y 10 por ciento por camada. Un rotavirus del grupo A fue demostrado por la técnica ELISA. Aparentemente la infección en lechones se originó por persistencia del virus en el medio ambient

    The Gulf Stream position influences the functional composition of phytoplankton in El Gergal reservoir (Spain)

    Get PDF
    The latitudinal position of the north-wall of the Gulf Stream influences the climatic conditions in the Atlantic North and Western Europe. Southerly movements of the Gulf Stream (low Gulf Stream Index values, GSI) typically induce unstable meteorological conditions in this region, while north displacements of the oceanic current (high GSI values) are associated with stable weather. In the present article we explore a seven years data set including annual GSI, meteorological records and phytoplankton community composition and abundance to demonstrate that the year-to-year changes in the position of the Gulf Stream and its influence on the prevailing weather conditions have an effect on the long-term variability of phytoplankton community in El Gergal reservoir, an ecosystem located in the Atlantic coast of Andalusia (SW Spain). Furthermore, we describe the response of each considered phytoplankton functional groups to changes in the Gulf Stream position. Thus, northerly displacements of the north-wall increased the abundance of H+S1 cyanobacteria through a non-linear function with two marked GSI thresholds. GSI and Lm dinoflagellates abundance depicted a significant positive linear correlation, while groups B + P diatoms abundance was negatively linear correlated with GSI. Groups Y cryptophytes and X1 + J chlorophytes abundance remained nearly constant for most of the studied years but developed an exponential increase at high GSI years. Implications for water quality management are pointed out.Las condiciones climáticas en la fachada Atlántica europea están influidas por las variaciones temporales en la posición latitudinal de la Corriente del Golfo en el océano Atlántico. Así, el desplazamiento hacia el Sur de la Corriente del Golfo (valores bajos del Índice de la Corriente del Golfo, GSI) induce condiciones de inestabilidad meteorológica en la Europa occidental, mientras que los desplazamientos septentrionales de la corriente oceánica (elevados valores del GSI) están asociados con mayor estabilidad meteorológica en esta región. Este artículo estudia la influencia de los cambios interanuales en la posición de la Corriente del Golfo sobre la comunidad fitoplanctónica del embalse de El Gergal, un ecosistema localizado en la costa atlántica andaluza (SW España). Para ello, a lo largo de siete años se han registrado valores anuales de GSI, información meteorológica y datos sobre la composición y biovolumen del fitoplancton. El análisis de esta información permite describir cómo las variaciones anuales en la posición de la Corriente del Golfo afectan a las condiciones meteorológicas en el área de estudio, influyendo de esta manera sobre el biovolumen de cada uno de los grupos funcionales de fitoplancton considerados. Los desplazamientos hacia el Norte de la Corriente del Golfo favorecieron el incremento del biovolumen de cianobacterias de los grupos H + S1 a través de una función no lineal con dos valores críticos de GSI bien definidos. Por su parte, se encontró una relación lineal positiva entre el GSI y el biovolumen de dinoflagelados del grupo Lm, mientras que las diatomeas de los grupos B + P se relacionaron de forma inversa con el GSI. Aunque el biovolumen de clorofitas de los grupos X1 + J y de criptofitas del grupo Y permaneció estable durante la mayor parte de los años estudiados, se registró un notable incremento del mismo en aquellos años en los que el GSI mostró sus valores más elevados. Finalmente se apuntan algunas consideraciones sobre posibles implicaciones en la gestión de la calidad del agua embalsada
    corecore