Cryopreservation of Gametes and Larvae of the Eastern Oyster Crassostrea Virginica.

Storage of gametes and larvae offers benefits for research and commercial oyster production and should be applicable in the hatchery at a commercial scale. We optimized refrigerated storage of eastern oyster sperm. Significant differences were found in the motility of sperm suspended in artificial sea water (ASW) of different osmotic pressures (P \u3c 0.001). The highest motility was found in undiluted sperm and the lowest in 1:31 dilution. The greatest larval survival at 12 h (48%) was obtained with sperm diluted in calcium-free Hanks\u27 balanced salt solution (C-F HBSS). Thus, for storage of longer than 1 d, it is best to leave samples undiluted. However, when sperm samples are diluted, it is best to maintain high sperm concentrations and to use C-F HBSS as an extender. Samples were frozen at -2.5°C/min, held for 5 min at -30°C, and plunged in liquid nitrogen using 10% propylene glycol (PG) as the cryoprotectant for sperm and 10% or 15% PG for trochophore larvae. Motility and fertilizing ability of thawed sperm were affected by cryoprotectant concentration and thawing temperature (P = 0.0001). Larval survival was affected by the concentration of larvae per straw (P = 0.0011). Frozen samples were transported to an oyster hatchery at Grand Isle, Louisiana. After 4 months, 1,000 oysters from the control group, 230 oysters produced from thawed sperm, and 850 oysters from thawed larvae were found. Oysters produced from thawed larvae developed normally in the hatchery, demonstrating opportunities for use of cryopreservation in research and aquaculture. Flow cytometry with the fluorescent dyes Sybr-14 and propidium iodide (PI) was used to assess membrane damage of thawed sperm, and rhodamine 123 and PI were used to assess mitochondrial function. Preliminary studies of cryopreservation of oyster eggs were performed. Fluorescein diacetate (FDA) was used to identify viable eggs. Dimethyl sulfoxide (0.88 M and 1.75 M) and sucrose (0.12 M and 0.25 M) were the least toxic cryoprotectants evaluated. The cooling rate yielding least damage to eggs was -1.5°C per min. However, only an average of 14 eggs (out of 200) were stained with FDA in thawed samples and none were fertilizable

Permanent and temporary ponds in Doñana National Park (SW Spain) are threatened by desiccation

In Doñana National Park, most aquatic habitats are temporary. Ponds dry up during the summer, and are filled again when phreatic levels rise after heavy rains. Permanent and semipermanent ponds, and a chain of long-hydroperiod ponds are formed in an area of the park where discharges of the dune and regional aquifers coincide. Over the last few decades, groundwater abstractions have severely affected the park. Using Landsat images (1975-2014), we estimated the variation in the inundated areas of the park’s largest ponds. All ponds have increased their dependency on annual rainfall in recent decades. Two seasonal ponds located close to urban pumping stations are currently dry. We found that other seasonal ponds have tended to have shorter hydroperiod and have dried up in the summer in recent years, including in very rainy years. The largest permanent pond had not such wide interannual fluctuations in its inundated area in the 1970s as those experienced recently. During the last decades, its inundated area is strongly correlated with annual rainfall, and the pond is close to desiccation in years of low rainfall. These results show that this pond network is severely threatened by desiccation. It is urgent to control groundwater extraction in the area to preserve the integrity of this important wetlandEn Doñana, la mayoría de los hábitats acuáticos son temporales. Las lagunas se desecan en verano y vuelven a inundarse con la elevación del nivel freático que se produce tras las abundantes lluvias otoñales o invernales. En la zona central del parque se localizan las lagunas permanentes y semipermanentes, que junto con otras de largo hidroperiodo forman una cadena de lagunas donde coinciden las descargas del acuífero dunar y el gran acuífero regional. En las últimas décadas, se han realizado extracciones de agua del acuífero que han afectado seriamente al parque. En este estudio, usando imágenes del satélite Landsat (1975-2014), hemos estimado la variación de la superficie inundada de las mayores lagunas del parque. En todas se observa un incremento en las últimas décadas de su dependencia de las lluvias anuales. Dos lagunas estacionales, situadas en las proximidades de estaciones de bombeo de aguas se consideran actualmente secas. En algunas lagunas, se observa una tendencia a acortar su periodo de inundación, secándose en los veranos de los años más recientes, incluso en años lluviosos. La laguna más permanente no sufría tan amplias variaciones en la superficie que mantenía inundada en verano en los años 70, como las que observan en la actualidad, cuando su inundación en verano está estrechamente correlacionada con las lluvias anuales, llegando en los últimos veranos a niveles muy próximos a la desecación. Estos resultados indican que la red de lagunas está severamente amenazada de desecación. Para preservar la integridad de este importante humedal, es urgente controlar las extracciones de agua del acuíferoPeer reviewe

El camaleón común (Chamaeleo chamaeleon) en la península ibérica

Peer reviewe

The conceptualization of school and teacher connectedness in adolescent research: A scoping review of literature

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/ licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The aim of this scoping review was to map and summarize research relating to school and teacher connectedness, in order to increase current understanding of the ways these terms have been conceptualized in adolescent research. Specifically, this scoping review focuses on the analysis of the actual definitions used and the ways in which school connectedness and teacher connectedness are operationalized in existing measures. Using the terms connectedness, teacher and school as keywords, we searched SCOPUS, Web of Science, ERIC, the Cochrane Library and the EPPI Centre Database of Education Research for relevant peer-review articles published in English from 1990 to 2016. 350 papers were selected for the review. Many studies failed to provide a definition of school or teacher connectedness and there were some differences in the way these constructs were operationalized in the main measures. Future research should be thorough in the definition of these constructs, and ensure consistency between the definition used and the operationalization of the connectedness construct in the selected measure. Unpacking the global concept of school connectedness and examining the role of its different components (global feelings towards school, teacher connectedness, relationships with classmates, etc.) separately may also contribute to building a more coherent body of evidence in this area. Reflecting on the place of school and teacher connectedness in the broader context of the literature on school climate and bridging distances between the research on school connectedness and that on related constructs is another necessary step to move this field forward.Peer reviewedFinal Published versio

Relationships between hydroperiod length, and seasonal and spatial patterns of beta-diversity of the microcrustacean assemblages in Mediterranean ponds

Temporary ponds are unpredictable habitats that exhibit inundation periods of variable duration (hydroperiods). We hypothesised that changes in microcrustacean assemblages, namely among ponds (spatial variation) and within ponds at a monthly scale (intra-annual variation), would differ according to hydroperiod length. We found that the microcrustacean assemblages of the study ponds demonstrated distinctive individual patterns that were dependent on monthly variation. During pond filling, species turnover was particularly high in short-hydroperiod ponds, probably due to the fast hatching of the initial pool of species, which seemed to determine subsequent species succession. Some of the long-hydroperiod ponds were able to hold water during the summer, which meant that they could harbour adult microcrustaceans in the early autumn, in contrast to the recently filled ponds; species turnover could thus increase at the onset of the inundation cycle. In the summer, species turnover decreased (while the contribution of nestedness to β-diversity increased) because only a few tolerant species were able to withstand the poor water quality found in drying ponds. We suggest that preserving the broader hydroperiod gradient, by protecting ponds with different environmental conditions within each hydroperiod category, would safeguard the ecological dynamics of the microcrustacean assemblages found in temporary pondsPeer reviewe

Wearable Structured Light System in Non-Rigid Configuration

Traditionally, structured light methods have been studied in rigid configurations. In these configurations the position and orientation between the light emitter and the camera are fixed and known beforehand. In this paper we break with this rigidness and present a new structured light system in non-rigid configuration. This system is composed by a wearable standard perspective camera and a simple laser emitter. Our non-rigid configuration permits free motion of the light emitter with respect to the camera. The point-based pattern emitted by the laser permits us to easily establish correspondences between the image from the camera and a virtual one generated from the light emitter. Using these correspondences, our method computes rotation and translation up to scale of the planes of the scene where the point pattern is projected and reconstructs them. This constitutes a very useful tool for navigation applications in indoor environments, which are mainly composed of planar surfaces

Galápago leproso – Mauremys leprosa (Schweigger, 1812)

Reptiles - Orden Quelonios - Familia Geoemydidae en la Enciclopedia Virtual de Vertebrados Españoles, http://www.vertebradosibericos.org/.A comprehensive review of the natural history of the Mediterranean stripe-necked terrapin Mauremys leprosa in Spain.Peer reviewe

Breathing technological air. Physical activity against technology’s effects on children

Premio extraordinario de Trabajo Fin de Máster curso curso 2020/2021. Máster en Neuropedagogía, Creatividad y Gestión de la Capacidad y del Talento. Aplicaciones Educativa