Spatial and temporal variability of suspended sediments concentration in Ria de Aveiro lagoon and fluxes between the lagoon and the ocean

The measurements of suspended sediment concentration in different parts of the Ria de Aveiro coastal lagoon during four tidal cycles show a significant spatial and temporal variability. Fluxes of water and suspended sediments between the lagoon and the coastal ocean were estimated for each tidal cycle applying a hydrodynamic two- dimensional numerical model and using the values measured at the lagoon mouth. The hydrodynamics of the lagoon are essentially dominated by tidal forcing. Tides are predominantly semidiurnal and are present in the entire lagoon The differences in suspended sediments concentration within the lagoon seem to be largely determined by the magnitude of the currents and by the bottom properties. As in other estuarine systems, the suspended sediments concentration fluctuated with tidal amplitude. In almost all stations, higher mean values occur during spring tides due to the strength of the tidal currents. Anomalous higher mean values observed in stations close to the tidal inlet during winter neap tide suggest that wind-induced resuspension and horizontal advection from the adjacent coastal area is taking place during that period of the year. Semidiurnal variations are explained, especially during the summer, by tidal-current velocity asymmetry (ebb dominance). Seasonal variability, with winter higher suspended sediments concentration, is probably related with wind climate, biological activity and coastal wave regime. In general, the fluxes of water and of suspended sediments between the lagoon and the coastal ocean showed a seaward flux that is consistent with the ebb dominance. Under winter neap tide conditions external factors allowed retention of suspended sediments in the lagoon

Data report: diatom and silicoflagellate records of marine isotope Stages 25-27 at IODP Site U1387, Faro Drift

During Integrated Ocean Drilling Program Expedition 339, the shipboard micropaleontological studies of Site U1387 core catcher samples revealed the preservation of diatoms and radiolarians in specific depths from early Pleistocene age (900–1000 ka). To evaluate the ecological significance of those diatoms, we analyzed 98 samples from the intervals of 244 to 274 m along the corrected splice, corresponding to marine isotope Stage (MIS) 25 to MIS 29, for the abundance of diatoms and silicoflagellates. In 6 samples, the composition of the diatom assemblage was determined as well. Although most samples were barren of siliceous microfossils, the downcore record revealed two intervals, 249–252 corrected meters composite depth (cmcd) and 263–265 cmcd, where diatoms and silicoflagellates reach their maximum values. These maxima occurred from the MIS 26/25 transition to interglacial MIS 25, and again during early MIS 27. The diatom assemblage includes 27 identified taxa with Chaetoceros (Hyalochaete) resting spores being dominant and Thalassionema nitzschioides and Paralia sulcata significant. The Chaetoceros spores clearly indicate strong influence of seasonal upwelling and associated high primary productivity. Special to the diatom record is, however, the occurrence of the large-diameter (>125 µm) centric diatoms Coscinodiscus asteromphalus, Coscinodiscus apiculatus, and Coscinodiscus cf. gigas that imply incursions of low-nutrient, open-ocean water into the southern Portuguese coast during MIS 25.FCT: IF/01500/2014. Provided by PTCRIS: 130279. UIDB/04326/2020info:eu-repo/semantics/publishedVersio

Influencia de la Laguna de Aveiro en los contenidos de metales pesados en la plataforma continental adyacente (Portugal)

A chemical analysis of Al, Ca, Fe, Mg, Cu, Pb, Zn, Cr, Co, Ni and Cd was carried out in 22 surface sediment samples of the continental shelf and upper slope between Espinho and Aveiro (Portugal). To reduce the disturbing effects of grain size, all samples were size-normalized by wet sieving (<63 µm). The fine fraction was digested with concentrated acids and analyzed by flame atomic absorption spectrometry. The Al and heavy metal concentrations displayed a similar distribution pattern, decreasing seaward. Exceptions to this general pattern are Ca, Mg and Pb distributions. The Ca contents are related to carbonated biogenic particles that are very abundant in the outer shelf. Multivariate statistical analysis was applied to all data to assess the behaviour and sources of each element analyzed. The results from factor analysis showed that terrigenous supply (from Aveiro Lagoon flow, coastal erosion and littoral drift), grain size (clay) sorting and anthropogenic influences from Aveiro Lagoon are the major factors controlling spatial variations of chemical elements in the continental shelf between Espinho and Aveiro. Unusually high contents of Pb were found in the middle shelf off Furadouro, but we could not determine the possible source of this contamination.Se realizaron análisis químicos de Al, Ca, Fe, Mg, Pb, Zn, Cr, Co, Ni y Cd en 22 muestras de sedimento superficial de la plataforma y vertiente continental entre Espinho y Aveiro (Portugal). Para reducir el efecto de la granulometría del sedimento, se normalizó el tamaño de las muestras mediante tamizado (<63 µm). Se procedió a la digestión de la fracción fina con ácidos concentrados y se analizó mediante espectrometría de absorción atómica con llama. Las concentraciones de Al y metales pesados muestran un patrón de distribución similar, disminuyendo hacia la vertiente. Las excepciones a este patrón general son las distribuciones de Ca, Mg y Pb. El contenido de Ca está relacionado con las partículas biogénicas carbonatadas que son muy abundantes en la plataforma externa. Con el objetivo de determinar el comportamiento y el origen de cada uno de los elementos analizados, se aplicaron técnicas de análisis estadístico multivariante. Los resultados obtenidos muestran que los principales factores que controlan las variaciones espaciales de los elementos químicos en la plataforma continental entre Espinho y Aveiro son los sedimentos terrígenos procedentes de la Laguna de Aveiro, de la erosión costera y de la deriva litoral; el tamaño de grano (tamaño arcillas); y la influencia antropogénica en la Laguna de Aveiro. En la plataforma media, a la altura de Furadouro, se encontraron valores elevados de Pb, aunque no hemos podido determinar la posible fuente de esta contaminación

Tenure matters for team cohesion and performance: The moderating role of trust in the coach

Research question: This study examines team performance as a function of team tenure, cohesion and trust in the coach. Specifically, we propose a moderated-mediation model to explain whether it translates into an objective measure of future team performance. Research methods: The study sample consists of 668 players from 73 professional and top amateur basketball league teams in Catalonia, Spain. Data collection consisted of a survey performed during a regular training session held at the beginning of the second part of the season as well as objective and subjective team performance indicators. Results and findings: Our findings suggest that the indirect effect of team tenure on performance through team cohesion is only significant for high and medium levels of cognitive trust in the coach and low levels of affective trust in the coach. Implications: These findings provide evidence that explains trust’s contribution to fostering team dynamics and how team tenure translates into future team performance. The practical implications of this study suggest that simply promoting team cohesion without taking into account the cognitive trust in the coach will not necessarily increase performance. Therefore, coaches and managers must invest in the amount of work they do with team members and their skills in order to ensure team members have high cognitive trust in them.info:eu-repo/semantics/acceptedVersio

Transformational leadership and team performance in sports teams: A conditional indirect model

This study tests how transformational leadership fosters team performance through team cohesion and how that relationship is moderated by previous team performance and leadership consensus. We computed a moderated-mediation model based on a sample of 690 professional players in 59 top professional teams in interactive team sports leagues (basketball, handball, roller hockey, and indoor football/soccer) in Spain. Our findings suggest that transformational leadership indirectly influences objective team performance through the mediation role of team cohesion and that this indirect effect is more prominent when the level of previous performance is higher. We also found that the indirect effect of transformational leadership on team performance via cohesion is stronger in teams with higher consensus regarding their coaches' leadership. Overall, our results demonstrate the importance of integrating dispersion and contextual variables into research models, in particular, previous performance and leadership consensus.info:eu-repo/semantics/publishedVersio

Pouvoir et leadership dans les écoles: Une étude sociologique dans des contextes défavorisés

Parte-se de uma perspectiva sociológica sobre o poder nas organizações escolares, baseada nas teorias consagradas de Max Weber e Crozier & Friedberg. Esta perspectiva é confrontada com estudos recentes sobre a liderança nas escolas e, posteriormente, é utilizada na análise dos processos de liderança em dois agrupamentos de escolas, localizados em contextos desfavorecidos, em regiões distintas de Portugal. Os “estudos de caso” envolveram a realização de entrevistas a professores com diversos cargos nos dois agrupamentos, um questionário aos docentes e outros aos encarregados de educação, bem como observação participante. A análise destaca a tensão entre lógicas legais e tradicionais de poder, a fragilidade do conselho geral e das lideranças intermédias, assim como hiatos de liderança pedagógica, apontando pistas para a sua superação.info:eu-repo/semantics/publishedVersio

First report on Meloidogyne chitwoodi hatching inhibition activity of essential oils and essential oils fractions

The Columbia root-knot nematode (CRKN), Meloidogyne chitwoodi, is an EPPO A2 type quarantine pest since 1998. This nematode causes severe damage in economically important crops such as potato and tomato, making agricultural products unacceptable for the fresh market and food processing. Commonly used nematicidal synthetic chemicals are often environmentally unsafe. Essential oils (EOs) may constitute safer alternatives against RKN. EOs, isolated from 56 plant samples, were tested against CRKN hatching, in direct contact bioassays. Some of the most successful EOs were fractionated and the hydrocarbon molecules (HM) and oxygen-containing molecules (OCM) fractions tested separately. 24 EOs displayed very strong hatching inhibitions (≥90 %) at 2 µL mL−1 and were further tested at lower concentrations. Dysphaniaambrosioides, Filipendula ulmaria, Ruta graveolens, Satureja montana and Thymbra capitata EOs revealed the lowest EC50 values (<0.15 µL mL−1). The main compounds of these EOs, namely 2-undecanone, ascaridol, carvacrol, isoascaridol, methyl salicylate, p-cymene and/or γ-terpinene, were putatively considered responsible for CRKN hatching inhibition. S. montana and T. capitata OCM fractions showed hatching inhibitions higher than HM fractions. The comparison of EO and corresponding fractions EC50 values suggests interactions between OCM and HM fractions against CRKN hatching. These species EOs showed to be potential environmentally friendly CRKN hatching inhibitors; nonetheless, bioactivity should be considered globally, since its HM and OCM fractions may contribute, diversely, to the full anti-hatching activity

In vitro co-culture of Solanum tuberosum hairy roots with Meloidogyne chitwoodi: structure, growth and production of volatiles

Meloidogyne spp., commonly known as root- knot nematodes (RKNs), are economically important plant sedentary endoparasites that cause galls on susceptible hosts. The Columbia root-knot nematode (CRKN), M. chitwoodi, is a quarantine A2 type pest by the European and Mediterranean Plant Protection Organization since 1998. This nematode has been found associated with economi- cally important crops such as potato and tomato, causing severe damage and making the agricultural products unac- ceptable for the fresh market and food processing. In vitro co-culture of host and parasite offers an advantageous experimental system for studying plant-RKN interactions. The structure, growth and production of volatiles of Sola- num tuberosum hairy roots (HR) and of S. tuberosum HR/ CRKN co-cultures were compared. HR were induced by inoculation of aseptic potato tuber segments with Rhizo- bium rhizogenes. Co-cultures were initiated by inoculating HR with sterilized CRKN eggs. Infection with CRKN induced the RKN symptomatology in the HR and several nematode life stages were observed by light and scanning electron microscopy. Potato HR and HR/CRKN co-culturesexhibited similar growth patterns, evaluated by measuring fresh and dry weight and by the dissimilation method. Volatiles, isolated by distillation–extraction and analyzed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry, revealed that palmitic acid (37–52 %), n–pentadecanal (10–16 %) and linoleic acid (2–16 %) were the main constitutive components of S. tu- berosum HR, and of the HR/CRKN co-cultures (24–44, 8–22 and 4–18 %, respectively). S. tuberosum HR/CRKN co-cultures can be considered a suitable biotechnological tool to study RKN infection mechanism by mimicking what occurs under field conditions