The influence of the Atlantic and regional climate variability on the long-term changes in gelatinous carnivore populations in the northwestern Mediterranean

We investigated potential connections between climate and the population size of gelatinous carnivores in the northwestern Mediterranean. The interannual variability of large- and meso-scale climate factors was related to gelatinous carnivore dynamics by means of a multivariate regression model. Gelatinous carnivore population dynamics integrate the climate-related changes in the northwestern Mediterranean with close correlations between climate and the population size of the Calycophoran siphonophores Chelophyes appendiculata and Abylopsis tetragona and the Hydromedusae Rhopalonema velatum and Solmundella bitentaculata. We show that the sensitivity of particular gelatinous carnivore species to environmental forcing relates to their seasonal appearance and peak of abundance. Our results advocate the occurrence of short time windows, during which gelatinous carnivores appear more sensitive to environmental conditions, and favorable conditions may therefore substantially enhance their annual peaks. Furthermore, there were threshold values from which climate effects on gelatinous carnivores become noticeable, indicating that the climate-gelatinous carnivore relationship intensifies according to the strength of climate forcing. The possibility of using the North Atlantic climate variability for assessing and predicting interannual abundance changes of these organisms in the northwestern Mediterranean is considered

Poblaciones europeas de jopo (O. cumana) virulentas en líneas de girasol con diferentes genes de resistencia

Resúmenes del XIII Congreso de la Sociedad Española de FitopatologíaPeer reviewe

Biomechanics of fish swimming in a hydrokinetic turbine wake

In the present paper, the assessment of the hydrodynamics of the fish swimming in undisturbed and altered wake-flow is carried out identifying hydrodynamical forces and flow patterns of the fish swimming wake. URANS approach with k-omega/SST turbulence model are employed combining fish and turbine in the same simulation. Fish motion is realized using dynamically adaptive mesh. The actuator line method is employed to induce the wake of a hydrokinetic turbine, which is a simplified method that requires lower computational cost than full geometry simulations. This work brings a new numerical approach involving fish and turbine wake highlighting that fish swimming in the wake presents higher thrust forces than in the undisturbed flow, due to the x-component to velocity in the wake is lower than free flow velocity

Motivation and academic achievement in mathematics: a longitudinal study in the early stages of education

Se analiza longitudinalmente la capacidad predictiva de un conjunto de variables motivacionales sobre el rendimiento matemático. Los análisis se realizan, en una muestra de 180 sujetos, con datos evaluados en dos momentos (Educación Infantil 5 años y 2º curso de Primaria). También se estudian las diferencias entre dos grupos, con rendimiento matemático medio y bajo al finalizar el primer ciclo de Primaria, en las variables motivacionales evaluadas en el primer momento. Los resultados muestran un importante poder predictivo sobre el rendimiento matemático posterior de la competencia percibida. También la persistencia, la actitud y la dimensión atribucional de internalidad positiva aportan una contribución significativa adicional. Los resultados muestran igualmente que los grupos con rendimiento medio y bajo al finalizar 2º de Primaria presentaban diferencias significativas a los 5 años, tanto en internalidad positiva como en persistencia. Se discuten las implicaciones teóricas y prácticas de los resultados.This longitudinal study analyzes the predictive value of a set of motivational variables on academic performance in mathematics area. Analyses were performed, in a sample of 180 subjects, with the data evaluated in two stages in formal educational settings (from kindergarten through 2nd grade of Primary School). Likewise, differences between groups, with average (AM) and low math performance (LM) at the end of the second year of Primary School, in motivational and attributional variables assessed at the first moment, are also studied. The results show a significant predictive power on later mathematics achievement for self-competence. Also persistence, attitude and positive attributional dimension of internality have an additional significant contribution. The results also show that average and low yield groups at the end of 2nd grade of Primary School, showed significant differences at 5 years both positive internality and persistence. These results are discussed in terms of their theoretical and practical implications

Long-term changes in phytoplankton phenology and community structure in the Bahía Blanca Estuary, Argentina

The phytoplankton of the Bahía Blanca Estuary, Argentina, has been surveyed since 1978. Chlorophyll a, phytoplankton abundance, species composition and physico-chemical variables have been fortnightly recorded. From 1978 to 2002, a single winter–early spring diatom bloom has dominated the main pattern of phytoplankton interannual variability. Such pattern showed noticeable changes since 2006: the absence of the typical winter bloom and changes in phenology, together with the replacement of the dominant blooming species, i.e. Thalassiosira curviseriata, and the appearance of different blooming species, i.e. Cyclotella sp. and Thalassiosira minima. The new pattern showed relatively short-lived diatom blooms that spread throughout the year. In addition, shifts in the phytoplankton size structure toward small-sized diatoms, including the replacement of relatively large Thalassiosira spp. by small Cyclotella species and Chaetoceros species have been noticed. The changes in the phenology and composition of the phytoplankton are mainly attributed to warmer winters and the extremely dry weather conditions evidenced in recent years in the Bahía Blanca area. Changing climate has modified the hydrological features in the inner part of the estuary (i.e. higher temperatures and salinities) and potentially triggered the reorganization of the phytoplankton community. This long-term study provides evidence on species-specific and structural changes at the bottom of the pelagic food web likely related to the recent hydroclimatic conditions in a temperature estuary of the southwestern Atlantic