Исследование сезонной изменчивости циркуляции вод Южной Атлантики по данным спутниковой альтиметрии

Исследован сезонный цикл течений на поверхности Южной Атлантики по данным спутниковой альтиметрии за период с 1992 по 2002 гг. Показано, что западные и восточные течения усиливаются с фазовой разницей в несколько месяцев, тогда как их широтные смещения квазисинхронны. Для течений тропической зоны наблюдается запаздывание сезонного сигнала с запада на восток в среднем на 2 – 3 месяца, в полярных широтах оно увеличивается до 6 месяцев.Seasonal cycle of the currents on the South Atlantic surface is investigated using the satellite altimetry data from 1992 to 2002. It is shown that the western and the eastern currents increase with phase difference in several months whereas their latitudinal displacements are quasi-synchronous. For the currents of the tropical zone the seasonal signal delay from the west to the east on average for 2 – 3 months can be observed; at polar latitudes it increases up to 6 months

Case report: Intrapulmonary tidal volumes in a preterm infant with chest wall rigidity

BACKGROUND Chest wall rigidity is a known side effect of fentanyl use, which is why fentanyl is usually combined with a muscle relaxant such as mivacurium. Verifying endotracheal intubation is difficult in case of a rigid chest wall. CASE PRESENTATION We present the case of a preterm infant (29 completed weeks gestation, birth weight 1,150 g) with a prolonged chest wall rigidity after fentanyl administration for intubation despite adequate doses of mivacurium. This resulted in a pronounced desaturation without any effect on heart rate. Clinically, the infant showed no chest wall movement despite intubation and common tools to verify intubation (including end-tidal carbon dioxide measurement and auscultation) were inconclusive. However, using electrical impedance tomography (EIT), we were able to demonstrate minimal tidal volumes at lung level and thereby, EIT was able to accurately show correct placement of the endotracheal tube. CONCLUSIONS This case may increase vigilance for fentanyl-induced chest wall rigidity in the neonatal population even when simultaneously administering mivacurium. Higher airway pressures exceeding 30 mmHg and the use of μ-receptor antagonists such as naloxone should be considered to reverse opioid-induced chest wall rigidity. Most importantly, our data may imply a relevant clinical benefit of using EIT during neonatal intubation as it may accurately show correct endotracheal tube placement

Estabilidad de las relaciones entre las agrupaciones de peces demersales y los factores ambientales-actividad pesquera a gran escala espacio-temporal en el norte del mar Mediterráneo

Trawling pressure and environmental changes may affect the composition of fish assemblages. Our knowledge on large spatio-temporal patterns of demersal fish composition remains incomplete for the Mediterranean Sea. We investigated (1) the spatio-temporal stability of demersal assemblages, (2) the relationships between these assemblages and potential structuring factors (trawling pressure and environmental conditions) in order to assess the dynamic of the assemblage structure at the scale of the northern Mediterranean Sea. We analysed a dataset of 18062 hauls from 10 to 800 m depth performed annually during the last two decades across 17 Geographical Sub-Areas (GSAs) (MEDITS program). A multi-table analysis (STATICO-CoA) evidenced a strong inter-GSAs stability in the organization of assemblages, with specificities for some GSAs. The most stable structuring factors were linked to combined gradients of chlorophyll a, phytoplancton carbon biomass and temperature, inversely correlated with depth, salinity and nutrient gradients (axis 1 of the STATICO-CoA compromise, 93.74% of the total variability). A common pattern linking the distribution of species to these environmental gradients was evidenced for most of the 17 GSAs. Estimate of trawling pressure showed a minor role in the organization of the assemblages for the spatial scale and years investigated (axis 2, 4.67%).La presión pesquera y los cambios ambientales pueden afectar a la composición de las agrupaciones de peces. En el Mediterráneo, nuestro conocimiento a gran escala sobre los patrones espacio-temporales de la composición de especies de peces demersales sigue siendo incompleto. Investigamos (1) la estabilidad espacio-temporal de las agrupaciones demersales (2) las relaciones entre dichas agrupaciones y los posibles factores estructurantes (presión pesquera de arrastre y condiciones ambientales) para evaluar la dinámica de la estructura de las agrupaciones en el norte del mar Mediterráneo. Analizamos un conjunto de 18062 lances entre 10 y 800 m. de profundidad realizados anualmente, durante las últimas dos décadas, en 17 sub-áreas geográficas (GSAs) (Proyecto MEDITS). El análisis multi-tablas (STATICO-CoA) evidenció una fuerte estabilidad inter-GSAs en la organización de agrupaciones, con especificidades para algunas GSAs. Los factores estructurantes más estables se relacionaron con los gradientes combinados de clorofila a, fitoplancton, carbono y temperatura, correlacionados inversamente con los gradientes de profundidad, salinidad y nutrientes (eje 1 del STATICO-CoA, 93.74% de la variabilidad total). En la mayoría de las GSAs encontramos un patrón común que vincula la distribución de las especies a estos gradientes ambientales. La estimación de la presión pesquera de arrastre mostró un papel menor en la organización de las agrupaciones para la escala espacial y los años investigados (eje 2, 4.67%)

Assessing functional evenness with the FEve index : a word of warning

Functional diversity has recently become a key challenge in community ecology due to its major importance for the understanding of ecosystem processes such as ecosystem productivity, the resilience of ecosystems to disturbances or invasions and regulation of the flux of matter. Some authors have argued that functional diversity can be divided into three independent components: functional richness, functional evenness and functional divergence. Currently, the evenness component of functional diversity is mainly assessed on the basis of the FEve index of Villeger et al. (2008) that quantifies the regularity of interspecies distances and the homogeneity of species abundances. Here, we demonstrate that the FEve index could give values that are not consistent with its claimed properties, and we illustrate this inconsistency with various specific examples. We highlight the fact that the FEve index can give values close to 1, although all species are not regularly spaced and have not the same abundance. We also demonstrate that two communities could have the same FEve index value although they differ in terms of abundance distribution. We assume that these characteristics are due to the fact that FEve index combines in a single value two different components: functional distance and distributions of species abundances. Finally, we propose an alternative solution to overcome the problem of these drawbacks, and thus achieve a more complete and accurate view of the functional evenness of communities

The multi-component structuration of the species diversity of groundfish assemblages of the east coast of Corsica (Mediterranean Sea) : Variation according to the bathymetric strata.

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A multi-component analysis of species diversity of groundfish assemblages on the continental shelf of the Gulf of Lions (north-western Mediteranean Sea)

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Assessment of coral reef fish biodiversity: how to choose the right indices

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Assessing functional diversity: the influence of the number of the functional traits

International audienceThe impact of the variation of the number of functional traits on functional diversity assessment is still poorly known. Although the covariation between these two parameters may be desirable in some situations (e.g. if adding functional traits provides relevant new functional information), it may also result from mathematical artefacts and lead to misinterpretation of the results obtained. Here, we have tested the behaviour of a set of nine indices widely used for assessing the three main components of functional diversity (i.e. functional richness, evenness and divergence), according to the variation in the number of functional traits. We found that the number of functional traits may strongly impact the values of most of the indices considered, whatever the functional information they contain. The FRic, TOP and n-hypervolume indices that have been developed to characterize the functional richness component appeared to be highly sensitive to the variation in the number of traits considered. Regarding functional divergence, most of the indices considered (i.e. Q, FDis and FSpe) also showed a high degree of sensitivity to the number of traits considered. In contrast, we found that indices used to compute functional evenness (FEve and Ru), as well as one of the indices related to functional divergence (FDiv), are weakly influenced by the variation in the number of traits. All these results suggest that interpretation of most of the functional diversity indices considered cannot only be based on their values as they are, but requires taking into account the way in which they have been computed