Contribution à l'étude du régime alimentaire, de la croissance et de la fécondité de la perche (Perca fluviatilis L.) dans un lac oligotrophe de région tempérée

La retenue de Sainte-Croix sur te Verdon, mise en eau il y a dix ans, est un lac oligotrophe monomictique chaud de 2 200 ha de surface et de 80 m de profondeur maximum (profondeur moyenne 50 m). Une vidange hivernale partielle en abaisse le niveau de 8 à 16 m selon les années. La température dans l'épilimnion varie de 7 °C en février à 22 °C en juillet, avec une moyenne de plus de 900 degrés/jours au-dessus de 14 °C.Les perches introduites depuis la mise en eau, se nourrissent des plus gros planctontes (Cladocères et Copépodes), des larves benthiques de divers insectes (Chironomides, Ephémères) ainsi que d'alevins. Malgré des conditions thermiques favorables, la croissance des perches est lente en raison de la faible densité des proies et de la concurrence avec des Cyprinidae planctonophages, ablettes et gardons, très bien représentés dans la retenue.La maturité sexuelle est atteinte au terme de ta première année pour la majorité des mâles, la seconde année seulement pour 60 % des femelles. Mesurée sur 15 femelles de 14 à 40 cm, la fécondité variant de 2 500 à 50 000 ovules, est faible.The large-scale hydro-electric reservoir of Lake Sainte-Croix fed by the Verdon river, was dammed in 1974 and holds 765 hm3, spreading over 2 200 ha at 477 meters above sea level. Its average and maximum depths-are 50 and 80 meters and the water level can fall 16 meters in Autumn and Winter, reducing the water cover by a maximum of 23 % during January and February. It is a warm monomictic lake where the hypolimnion is well oxygenated in all seasons. The water has an alkaline pH and is relatively poor in nutritional salts. Controlled by water temperature during the mixing period, the primary production, always tow, is limited by loss of nitrogen in the epilimnion and lack of light in the hypolimnion during the thermal stratified period.The epilimnion temperature varies from 7 °C in February to 22 °C in July, with an average of more than 900 degrees per day per year above 14 °C. In addition to the various indigenous species, perch, roach and bleak are stocked, the latter two species being predominant now. The stomach contents of perch fished with nets and by electrical means during the Winter (December-March) and Summer (August) periods were examined and the animals' ages were determined using the opecularbone method. The scarcity of plankton compels the young as well as the adult perch to feed on macroinvertebrates of benthos. This trophic niche overlap between the two size groups creates intraspecific competition. The availability of benthic prey is conditioned to a great extent by the receeded water line in Winter (Winter tide) which leaves the essential feeding ground dry for several months and limits the development of aquatic vegetation. The existence of an interspecific roach-bleak competition, especially noticeable between the young planktivorous fry, accentuates the effects of the poor nutritional conditions on the rate of perch reproduction which is among the lowest on record. Sexual maturity is reached at the end of the first year for the males, and during the second year for only 50 % of the females. The absolute fertility measured on 15 females between 14 and 40 cm, varied from 2,500 to 50,000 eggs

LAS TECNOLOGÍAS DE LA INFORMACIÓN Y COMUNICACIÓN (TIC) Y SU IMPACTO EN LA EDUCACIÓN DEL SIGLO XXI

En este artículo se describe la evolución de las Tecnologías de Información y Comunicación y los consecuentes efectos en el proceso educativo, sobre la base de lo audiovisual como forma diferenciada de expresión y no como recurso tecnológico. Se muestra la transformación del rol de los docentes y de los estudiantes como consecuencia de las revoluciones educacionales y las implicaciones socioculturales que impulsa estos cambios tecnológicos. Igualmente se analiza la brecha digital, la nueva forma de exclusión social y el control de la información. Adicionalmente se hace un breve análisis diacrónico sobre el modo en que se ha concebido la enseñanza. Es por tanto un ensayo que aproxima una interpretación del cambio cultural que engendran los nuevos medios de comunicación. Finalmente se presentan las conclusiones a manera de reflexiones sobre la base del papel imprescindible que desarrolla el educador del nuevo siglo

Uso del mini nutritional assesment como herramienta de cribaje nutricional en la población mayor de 65 años en el ámbito hospitalario; conveniencia y factibilidad

The high prevalence of malnutrition in the growing population of older adults makes malnutrition screening critical, especially in hospitalized elderly patients. The aim of our study was to evaluate the use of the MNA® Mini Nutritional Assessment in hospitalized older adults for rapid evaluation of nutritional risk. A prospective cohort study was made of 106 patients 65 years old or older admitted to an internal medicine ward of a tertiary-care teaching hospital to evaluate the use of the short form, or screening phase, of the MNA-SF. In the first 48 hours of admission, the full MNA questionnaire was administered and laboratory tests and a dermatologic evaluation were made. The MNA score showed that 77% of the patients were at risk of malnutrition or were frankly malnourished. Low blood levels of albumin, cholesterol and vitamins A and D showed a statistically significant association with malnutrition or risk of malnutrition. Separate evaluation of the MNA-SF showed that it was accurate, sensitive and had predictive value for the screening process. Routine use of the MNA-SF questionnaire by admission nurses to screen patients is recommended. Patients with MNA-SF scores of 11 or lower should be specifically assessed by the nutritional intervention teamEl envejecimiento de la población y la elevada prevalencia de desnutrición en este colectivo hacen que el cribaje de desnutrición sea fundamental, especialmente en ancianos ingresados. Realizamos un estudio prospectivo sobre una población de 106 pacientes mayores de 65 años, ingresados en plantas de Medicina Interna de un hospital terciario, en el que se ha seguido la aplicación sistemática de Minimal Nutritional Assessment (MNA) en las primeras 48 horas de ingreso, así como una evaluación hematológica y dermatológica. Hemos detectado situación nutricional de riesgo (RM) o malnutrición (MN) en el 77% de los casos. Los marcadores biológicos que resultaron asociados estadísticamente a la MN o RM fueron la hipoalbuminemia, hipocolesterolemia, así como la hipovitaminosis A y D. Proponemos el empleo rutinario de la fase de cribaje del MNA por la enfermera de hospitalización, y la valoración específica por equipo especializado (Unidad de Nutrición) en caso de puntuación igual o inferior a 1

Intercalibration of four spectrofluorometric protocols for measuring RNA/DNA ratios in larval and juvenile fish

The ratio of tissue RNA to DNA (R/D) is a widely used index of recent growth and nutritional condition in larval and juvenile fish. To date, however, no standard technique for measuring nucleic acids has been adopted. Because methodological details can affect the estimate of R/D, researchers using different analytical protocols have been unable to compare ratios directly. Here, we report on the results of an international interlaboratory calibration of 4 spectrofluorometric protocols to quantify nucleic acids. Replicate sets of 5 tissue samples and 2 standards (common standards) were supplied to each of 5 researchers for analysis with their own methods and standards. Two approaches were evaluated for mitigating the observed differences in values: 1) the use of common nucleic acid standards and 2) standardizing to a common slope ratio (slope of DNA standard curve/slope of RNA standard curve or mDNA/mRNA). Adopting common standards slightly reduced the variability among protocols but did not overcome the problem. When tissue R/Ds were standardized based on a common mDNA/mRNA slope ratio, the variance attributed to analytical protocol decreased dramatically from 57.1% to 3.4%. We recommend that the ratio of the slopes of the standard curves be provided to facilitate intercomparability of R/D results among laboratories using different spectrofluorometric methods for the analysis of nucleic acids in fish

Active flux seasonality of the small dominant migratory crustaceans and mesopelagic fishes in the Gulf of California during June and October

The biological carbon pump is the process that transports carbon vertically out of the mixed layer in the ocean. Besides the sinking flux of organic particles, active flux due to the daily vertical migration of zooplankton and micronekton promotes a significant carbon transport not fully accounted for or understood in the world’s oceans. The diversity and abundance of epipelagic and mesopelagic species in the Gulf of California has been extensively studied, but the role of micronekton in carbon export has not yet been investigated. We studied the carbon flux promoted by juvenile and adult mesopelagic fishes and crustaceans (Decapoda and Euphausiidae) during the transition from the cold to warm period (June) and the onset of the warm season (October) in 2018. We provide the first estimation of migrant biomass and respiratory flux of the most abundant migratory species of mesopelagic fishes, decapods and euphausiids in the Gulf of California. The micronekton species collected accounted for a large biomass of mesopelagic fishes and pelagic crustaceans. The average migrant biomass estimates were 151.5 ± 101.2 mg C·m−2 during June and 90.9 ± 75.3 mg C·m−2 during October. The enzymatic activity of the electron transfer system (ETS) was measured as an estimate of their respiratory rates. Average specific ETS activity was significantly different between fishes and decapods, and between fishes and euphausiids (p < 0.05). The respiratory flux of fishes was predominant in the Gulf of California, followed by pelagic decapods and euphausiids. Seasonal changes in respiratory flux were observed for fishes (June: 6.1 ± 1.5 mg C·m−2·d−1; October: 3.2 ± 1.8 mg C·m−2·d−1) and decapods (June: 0.4 mg C·m−2·d−1; October: 0.7 ± 0.05 mg C·m−2·d−1). Respiratory flux estimation by crustaceans (decapods and euphausiids) and fishes together was 6.86 mg C·m−2·d−1 during June, and 4.21 mg C·m−2·d−1 during October 2018, suggesting a functional role of this large micronektonic fauna in the biological carbon export in this region.3,26

Large-scale ocean connectivity and planktonic body size

Villarino, Ernesto ... et al.-- 13 pages, 5 figures, 5 tables, supplementary material https://dx.doi.org/10.1038/s41467-017-02535-8Global patterns of planktonic diversity are mainly determined by the dispersal of propagules with ocean currents. However, the role that abundance and body size play in determining spatial patterns of diversity remains unclear. Here we analyse spatial community structure - β-diversity - for several planktonic and nektonic organisms from prokaryotes to small mesopelagic fishes collected during the Malaspina 2010 Expedition. β-diversity was compared to surface ocean transit times derived from a global circulation model, revealing a significant negative relationship that is stronger than environmental differences. Estimated dispersal scales for different groups show a negative correlation with body size, where less abundant large-bodied communities have significantly shorter dispersal scales and larger species spatial turnover rates than more abundant small-bodied plankton. Our results confirm that the dispersal scale of planktonic and micro-nektonic organisms is determined by local abundance, which scales with body size, ultimately setting global spatial patterns of diversityThis research was funded by the project Malaspina 2010 Circumnavigation Expedition (Consolider-Ingenio 2010, CSD2008-00077) and cofounded by the Basque Government (Department Deputy of Agriculture, Fishing and Food Policy). [...] E.V. was supported by a PhD Scholarship granted by the Iñaki Goenaga−Technology Centres FoundationPeer Reviewe

Spatial variability of shear wave velocity: implications for the liquefaction response of a case study from the 2010 Maule Mw 8.8 Earthquake, Chile

Assessing the potential and extent of earthquake-induced liquefaction is paramount for seismic hazard assessment, for the large ground deformations it causes can result in severe damage to infrastructure and pose a threat to human lives, as evidenced by many contemporary and historical case studies in various tectonic settings. In that regard, numerical modeling of case studies, using state-of-the-art soil constitutive models and numerical frameworks, has proven to be a tailored methodology for liquefaction assessment. Indeed, these simulations allow for the dynamic response of liquefiable soils in terms of effective stresses, large strains, and ground displacements to be captured in a consistent manner with experimental and in-situ observations. Additionally, the impact of soil properties spatial variability in liquefaction response can be assessed, because the system response to waves propagating are naturally incorporated within the model. Considering that, we highlight that the effect of shear-wave velocity Vs spatial variability has not been thoroughly assessed. In a case study in Metropolitan Concepción, Chile, our research addresses the influence of Vs spatial variability on the dynamic response to liquefaction. At the study site, the 2010 Maule Mw 8.8 megathrust Earthquake triggered liquefaction-induced damage in the form of ground cracking, soil ejecta, and building settlements. Using simulated 2D Vs profiles generated from real 1D profiles retrieved with ambient noise methods, along with a PressureDependentMultiYield03 sand constitutive model, we studied the effect of Vs spatial variability on pore pressure generation, vertical settlements, and shear and volumetric strains by performing effective stress site response analyses. Our findings indicate that increased Vs variability reduces the median settlements and strains for soil units that exhibit liquefaction-like responses. On the other hand, no significant changes in the dynamic response are observed in soil units that exhibit non-liquefaction behavior, implying that the triggering of liquefaction is not influenced by spatial variability in Vs. We infer that when liquefaction-like behavior is triggered, an increase of the damping at the shallowest part of the soil domain might be the explanation for the decrease in the amplitude of the strains and settlements as the degree of Vs variability increases

Concise Reporting of Benign Endometrial Biopsies is an Acceptable Alternative to Descriptive Reporting

In the United Kingdom, endometrial biopsy reports traditionally consist of a morphologic description followed by a conclusion. Recently published consensus guidelines for reporting benign endometrial biopsies advocate the use of standardized terminology. In this project we aimed to assess the acceptability and benefits of this simplified "diagnosis only" format for reporting non-neoplastic endometrial biopsies. Two consultants reported consecutive endometrial biopsies using 1 of 3 possible formats: (i) diagnosis only, (ii) diagnosis plus an accompanying comment, and (iii) the traditional descriptive format. Service users were asked to provide feedback on this approach via an anonymized online survey. The reproducibility of this system was assessed on a set of 53 endometrial biopsies among consultants and senior histopathology trainees. Of 370 consecutive benign endometrial biopsies, 245 (66%) were reported as diagnosis only, 101 (27%) as diagnosis plus a brief comment, and 24 (7%) as diagnosis following a morphologic description. Of the 43 survey respondents (28 gynecologists, 11 pathologists, and 4 clinical nurse specialists), 40 (93%) preferred a diagnosis only, with 3 (7%) being against/uncertain about a diagnosis only report. Among 3 histopathology consultants and 4 senior trainees there was majority agreement on the reporting format in 53/53 (100%) and 52/53 (98%) biopsies. In summary, we found that reporting benign specimens within standardized, well-understood diagnostic categories is an acceptable alternative to traditional descriptive reporting, with the latter reserved for the minority of cases that do not fit into specific categories. This revised approach has the potential to improve reporting uniformity and reproducibility

Vertical distribution of fish larvae in the Canaries-African coastal transition zone, in summer

13 pages, 6 figures, 2 tables.-- Printed version published Jul 2006.This study reports the vertical distribution of fish larvae during the 1999 summer upwelling season in the Canaries-African Coastal Transition Zone (the Canaries-ACTZ). The transition between the African coastal upwelling and the typical subtropical offshore conditions is a region of intense mesoscale activity that supports a larval fish population dominated by African neritic species. During the study, the thermal stratification extended almost to the surface everywhere, and the surface mixed layer was typically shallow or non-existent. Upwelling occurred on the African shelf in a limited coastal sub-area of our sampling. The vertical distributions of the entire larval fish population, as well as of individual species, were independent of the seasonal thermocline. Fish larvae and mesozooplankton were concentrated at intermediate depths regardless of the thermocline position, probably because of its weak signature and spatial and temporal variability. Day/night vertical distributions suggest that some species did not perform diel vertical migration (DVM), whereas others showed either type I DVM or type II DVM. The opposing DVM patterns of different species compensate for each other resulting in no net DVM for the larval fish population as a whole.Fieldwork was carried out as part of the CANIGO project, funded by the EU, and of the "Pelagic (EU-CICYT 1FD97-1084)" project from the Spanish Ministry of Education and the European Union