Cold storage of sperm of rainbow trout (Oncorhynchus mykiss): Effect on motility, intracellular superoxide, plasma membrane integrity and mitochondrial membrane potential

In teleostei, as opposed to what happens in mammals, most of the studies that evaluate the quality storages of semen are oriented toward the exposure of spermatozoa to some reactive oxygen species (ROS), the utilization of antioxidants in the diet, or the incorporation of these in seminal plasma. There is no available the literature covering the presence of superoxide ions (O 2.-), or the function of these on the interior of the spermatozoa that have been stored. In this study, we evaluated the effect of storage on intracellular O2.-, motility, plasmatic membrane integrity, and mitochondrial membrane potential (ΔΨMit) of spermatozoa of rainbow trout (oncorhynchus mykiss). Semen was extracted and put into storage for 12 days at 4 °C. Spermatozoa motility, (ΔΨMit), plasmatic membrane integrity were evaluated every 4 days, and intracellular O2. was detected. It was found that 82.59% of the cells were positive for the staining of O2. on the day of sample extraction, while sperm motility, ΔΨMit and plasmatic membrane integrity only showed deterioration after the eighth day of storage. Only ΔΨ Mit is correlated negatively with O2. starting from the eighth day of storage (r = -0.56 P &lt; 0.05). Regarding motility and plasmatic membrane integrity, these were not affected by intracellular O2., although the deterioration observed in these last two indicators, could have been caused by the prolonged contact of the spermatozoa with contaminating agents that were not evaluated in this study.A diferencia de lo que ocurre en mamíferos, en teleósteos la mayoría de los estudios que evalúan la calidad del semen almacenado están orientados a la exposición de los espermatozoides a algunas especies reactivas de oxígeno (ROS), a la incorporación de antioxidantes en la dieta o a la aplicación de éstos en el plasma seminal. No se encuentran trabajos disponibles que traten la presencia del radical superóxido (O2._), ni la función que éste cumple al interior del espermatozoide cuando se encuentran almacenados. En la presente investigación se evaluó el efecto del almacenamiento en el O2._, motilidad, integridad de la membrana plasmática y potencial de membrana mitocondrial (ΔΨMit) en espermatozoides de trucha arcoiris (oncorhynchus mykiss). Para ello se extrajo el semen, el cual fue almacenado durante 12 días a 4 ºC. Cada 4 días se evaluó motilidad, ΔΨMit, integridad de la membrana plasmática y se detectó O2._ intracelular en los espermatozoides. Se encontró un 82,59% de células con tinción positiva para O2._ el día de extracción de la muestra, mientras que la motilidad, ΔΨMit y la integridad de la membrana plasmática, solo mostraron deterioro después del octavo día de almacenamiento. Únicamente el ΔΨMit se correlaciona negativamente con O2._ a partir del octavo día de almacenamiento (r = -0,56 P < 0,05). Respecto a la motilidad e integridad de la membrana plasmática no fueron afectadas por el O2._ intracelular, no obstante el deterioro observado en estos dos últimos indicadores podría deberse al contacto prolongado de los espermatozoides con agentes contaminantes no evaluados en el presente trabajo

RASGOS DE LOS FORÓFITOS DE GUAZUMA ULMIFOLIA Y SAMANEA SAMAN Y SU INFLUENCIA EN LA DISTRIBUCIÓN ESPACIAL, ABUNDANCIA Y DIVERSIDAD DE PLANTAS EPÍFITAS

Bark traits in phorophytes influence the establishment and spatial distribution of epiphytic plants. Given this, at the campus of the Universidad Técnica Nacional, in Atenas, Costa Rica, bark surface rugosity and water retention capacity of Guazuma ulmifolia and Samanea saman were evaluated. The diversity and similarity indices of epiphytic plants present in each phorophyte were analyzed. Thirty phorophytes, 15 from G. ulmifolia and 15 from Samanea saman, were marked and georeferenced and zoned according to the Johansson zone classification, and subsequently, the&nbsp;species that grow in each zone were inventoried. We registered 447 epiphytes, belonging to 9 families, 21 genera and 35 species. The phorophytes did not show a homogeneous distribution of epiphytes within their strata (stem and canopy) and the distribution of species by Johansson zone is different. Epiphytic species with host specificity were identified. A positive and highly significant correlation was determined between DAP and the abundance of epiphytes in S. saman.Los rasgos de la corteza en los forófitos influyen en el establecimiento y la distribución espacial de plantas epífitas. Ante esto, en el campus de la Universidad Técnica Nacional, sede Atenas, Costa Rica, se evaluó la rugosidad y la capacidad de retención de agua en la corteza de Guazuma ulmifolia y Samanea saman. Se analizó los índices de diversidad y similitud de plantas epífitas presentes en cada forófito. Se marcó y georreferenció 30 forófitos, 15 de G. ulmifolia y15 de Samanea saman, y se zonificaron según la clasificación de las zonas de Johansson, y posteriormente se inventariaron las especies que crecen en cada zona. Se registraron 447 epífitas, pertenecientes a nueve familias, 21 géneros y 35 especies. Los forófitos no mostraron una distribución homogénea de epífitas dentro de sus estratos (fuste y copa del árbol) y la distribución de especies por zona de Johansson es diferente. Se identificaron especies epífitas con especificidad de hospedero. Se determinó una correlación positiva y altamente significativa entre el DAP y abundancia de epífitas en S. saman

Composición florística de la regeneración natural de un bosque muy húmedo premontano en Poás, Costa Rica

ABSTRACT. “Floristic composition of the natural regeneration of very wet premontane forest in Poás, Costa Rica”. Introduction: Natural restoration is a low cost and nature-based way to restore part of habitats degraded by deforestation. Objective: To document the floristic composition of a regenerating vegetation fragment of very wet premontane forest. Methods: We did a floristic inventory in 5,59ha through exhaustive walks. Results: We documented 74 families, 144 genera and 170 native species, and 15 families, 21 genera and 22 exotic species, and one hybrid. The families with the highest genera and species riches were Asteraceae, Fabaceae, Solanaceae, Rubiaceae, Euphorbiaceae, Polypodiaceae, Lauraceae, and Pteridaceae. The genera with the highest species richness were Solanum, Pleopeltis, Pteris, Croton, and Piper. We identified two endemic species, Costus montanus and Sechium tacaco. 95% of the species are terrestrial, 4% facultative epiphytes, and 1% holoepiphytes; 30% trees, 29% shrubs, 27% herbs, 9% lianas, and 5% dwarf shrub. About 64% are strictly heliophytes, and 36% of the species may tolerate shade. 148 species have at least one vernacular name. Conclusion: It is relevant to conserve this forest fragment, which is in an early state of regeneration, because its species composition typical of the premontane forests of the Costa Rican Central Valley.  RESUMEN. Introducción: La regeneración natural es una solución de bajo costo y basada en la naturaleza para restaurar parte de los hábitats degradados por la deforestación. Objetivo: Documentar la composición florística de un fragmento de vegetación en regeneración de bosque muy húmedo premontano. Métodos: Hicimos un inventario florístico en 5,59ha mediante recorridos exhaustivos. Resultados: Identificamos 74 familias, 144 géneros y 170 especies nativas, y 15 familias, 21 géneros y 22 especies introducidas, y un híbrido. Las familias con mayor riqueza de géneros y especies fueron Asteraceae, Fabaceae, Solanaceae, Rubiaceae, Euphorbiaceae, Polypodiaceae, Lauraceae y Pteridaceae. Los géneros con mayor riqueza de especies fueron Solanum, Pleopeltis, Pteris, Croton y Piper. Hallamos dos especies endémicas, Costus montanus y Sechium tacaco. El 95% de las especies son terrestres, 4% epífitas facultativas y 1% holoepífitas; 30% árboles, 29% arbustos, 27% hierbas, 9% lianas y 5% sufrútices. Cerca del 64% son estrictamente heliófitas, y un 36% de las especies pueden tolerar la sombra. 148 especies tiene al menos nombre común. Conclusión: Este bosque se encuentra en un estado temprano de regeneración, con una composición de especies típica de los bosques premontanos del Valle Central costarricense, por lo que es relevante conservarlo.

Charge Exchange Processes between Excited Helium and Fully Stripped Ions

We made a classical trajectory Monte Carlo (CTMC) calculation of state selective cross sections for processes between some light ions and excited helium. The results, useful for analysis of spectroscopic data of fusion devices, are in good agreement with theoretical predictions of scaling laws.Comment: LaTex, 8 pages, 4 figures (available on request to the authors), DFPD/94/TH/57, to be published in Phys. Rev.

Personal and environmental factors associated with active commuting to school in Switzerland

Objective. To assess whether prevalence of active commuting and regular car trips to school varies across communities and language regions in Switzerland and to determine personal and environmental correlates. Methods. During the school year 2004/2005, 1345 parental questionnaires (response rate 65%) of children attending 1st, 4th and 8th grades were completed, 1031 could be linked to a GIS environmental database. A German-speaking, a French-speaking and a bilingual study area were included. Usual mode of transportation and frequency of regular car trips to school were assessed. Associations with personal and environmental factors were evaluated with multivariate regression models. Results. Seventy-eight percent of the children actively traveled to school. Twelve percent were regularly driven at least once a week by car. Major road crossings and distance were significantly related to usual mode of transportation, but not to regular car trips. Age, daycare attendance, parental safety concerns, number of cars in the household and belonging to French-speaking population were significantly associated with increased regular car trips. Conclusion. Objective predictors are main deciding factors for active commuting to school as main mode of transport whereas personal and lifestyle factors are important factors associated with frequency of car use. Not only objective but also differing cultural attitudes should be considered when promoting non-motorized travel

Violation of the string hypothesis and Heisenberg XXZ spin chain

In this paper we count the numbers of real and complex solutions to Bethe constraints in the two particle sector of the XXZ model. We find exact number of exceptions to the string conjecture and total number of solutions which is required for completeness.Comment: 15 pages, 7 Postscript figure

Veritas & Vanitas

A journal of creative nonfiction produced by students at the Marion campus of The Ohio State University with contributions from the students and faculty at the Marion campus of The Ohio State University and Marion Technical College

Time-domain NIRS system based on supercontinuum light source and multi-wavelength detection: Validation for tissue oxygenation studies

We present and validate a multi-wavelength time-domain near-infrared spectroscopy (TD-NIRS) system that avoids switching wavelengths and instead exploits the full capability of a supercontinuum light source by emitting and acquiring signals for the whole chosen range of wavelengths. The system was designed for muscle and brain oxygenation monitoring in a clinical environment. A pulsed supercontinuum laser emits broadband light and each of two detection modules acquires the distributions of times of flight of photons (DTOFs) for 16 spectral channels (used width 12.5 nm / channel), providing a total of 32 DTOFs at up to 3 Hz. Two emitting fibers and two detection fiber bundles allow simultaneous measurements at two positions on the tissue or at two source-detector separations. Three established protocols (BIP, MEDPHOT, and nEUROPt) were used to quantitatively assess the system's performance, including linearity, coupling, accuracy, and depth sensitivity. Measurements were performed on 32 homogeneous phantoms and two inhomogeneous phantoms (solid and liquid). Furthermore, measurements on two blood-lipid phantoms with a varied amount of blood and Intralipid provide the strongest validation for accurate tissue oximetry. The retrieved hemoglobin concentrations and oxygen saturation match well with the reference values that were obtained using a commercially available NIRS system (OxiplexTS) and a blood gas analyzer (ABL90 FLEX), except a discrepancy occurs for the lowest amount of Intralipid. In-vivo measurements on the forearm of three healthy volunteers during arterial (250 mmHg) and venous (60 mmHg) cuff occlusions provide an example of tissue monitoring during the expected hemodynamic changes that follow previously well-described physiologies. All results, including quantitative parameters, can be compared to other systems that report similar tests. Overall, the presented TD-NIRS system has an exemplary performance evaluated with state-of-the-art performance assessment methods

Magnetohydrodynamic equilibria of a cylindrical plasma with poloidal mass flow and arbitrary cross section shape

The equilibrium of a cylindrical plasma with purely poloidal mass flow and cross section of arbitrary shape is investigated within the framework of the ideal MHD theory. For the system under consideration it is shown that only incompressible flows are possible and, conscequently, the general two dimensional flow equilibrium equations reduce to a single second-order quasilinear partial differential equation for the poloidal magnetic flux function $\psi$, in which four profile functionals of $\psi$ appear. Apart from a singularity occuring when the modulus of Mach number associated with the Alfv\'en velocity for the poloidal magnetic field is unity, this equation is always elliptic and permits the construction of several classes of analytic solutions. Specific exact equlibria for a plasma confined within a perfectly conducting circular cylindrical boundary and having i) a flat current density and ii) a peaked current density are obtained and studied.Comment: Accepted to Plasma Physics & Controlled Fusion, 14 pages, revte