762 research outputs found
Symbiont diversity is not involved in depth acclimation in the Mediterranean sea whip Eunicella singularis
In symbiotic cnidarians, acclimation to depth and lower irradiance can involve physiological changes in the photosynthetic dinoflagellate endosymbiont, such as increased chlorophyll content, or qualitative modifications in the symbiont population in favour of better adapted strains. It has been argued that a lack of capacity to acquire new symbionts could limit the bathymetric distribution of the host species, or compromise its long-term survival in a changing environment. But is that always true? To address this question, we investigated the symbiont genetic diversity in Eunicella singularis, a Mediterranean sea whip species with a wide bathymetric distribution (10 to 50 m depth), which has recently suffered from mass mortalities after periods of abnormally high sea temperatures. We measured symbiont population densities and chlorophyll content in natural populations, and followed the response of the holobionts after reciprocal transplantations to deep and shallow depths. A total of 161 colonies were sampled at 2 depths (10 and 30 m) at 5 sites in the northwestern Mediterranean. All colonies harboured a single ribosomal Symbiodinium clade (A'), but a relatively high within-clade genetic diversity was found among and within colonies. This diversity was not structured by depth, even though the deeper colonies contained significantly lower population densities of symbionts and less chlorophyll. We did, however, reveal host-symbiont specificity among E. singularis and other Mediterranean cnidarian species. Transplantation experiments revealed a limit of plasticity for symbiont population density and chlorophyll content, which in turn questions the importance of the trophic role of Symbiodinium in E. singularis
Contribution of multi-temporal remote sensing images to characterize landslide slip surface ‒ Application to the La Clapière landslide (France)
Landslide activity is partly controlled by the geometry of the slip surface. This activity is traduced at the surface by displacements and topographic variations. Consequently, multi-temporal remote sensing images can be used in order to characterize the geometry of landslide slip surface and its spatial and temporal evolution. Differential Digital Elevation Models (DEMs) are obtained by subtracting two DEMs of different years. A method of multi-temporal images correlation allows to generate displacement maps that can be interpreted in terms of velocity and direction of movements. These data are then used to characterize qualitatively the geometry of the slip surface of the la Clapière landslide (French Southern Alps). Distribution of displacement vectors and of topographic variations are in accordance with a curved slip surface, characterizing a preferential rotational behaviour of this landslide. On the other hand, a spatial and temporal evolution of the geometry of the slip surface is pointed out. Indeed, a propagation of the slip surface under the Iglière bar, in the W part of the landslide, is suspected and can be linked to the acceleration of the landslide in 1987. This study shows the high potential of multi-temporal remote sensing images for slip surface characterization. Although this method could not replace in situ investigations, it can really help to well distribute geophysical profiles or boreholes on unstable areas
The paleoneurology of Ichthyopterygia and Sauropterygia:Diverse Endocranial Anatomies of Secondarily Aquatic Diapsids
Most meso- and megapredatory niches across Mesozoic marine ecosystems were gradually occupied by the secondarily aquatic Ichthyopterygia and Sauropterygia. Although their presumed Early Triassic origins remain obscured, the subsequent radiation and diversification of these diapsid superorders is reasonably well documented in the fossil record. In the first quarter of the twentieth century, the Triassic sauropterygian genera Nothosaurus and Placodus were among the first taxa for which the cranial endocast was extracted and described. The advent of computed tomography, circa 50 years after these pivotal paleoneurological investigations, has led to its adoption as the tool of choice for the non-destructive assessment of neurosensory adaptations in extinct vertebrates. Despite the increasing availability of paleoneurological data on extinct diapsids, Ichthyopterygia and Sauropterygia have received relatively modest, albeit growing, attention since. Here we review paleoneurological insights gleaned from these fossils to date and identify endocranial and neurosensory modifications associated with increasingly pelagic lifestyles and ecological specializations. Nevertheless, a broader ichthyopterygian and sauropterygian sample will be required to facilitate high-resolution taxon-wide comparisons and discern between endocranial changes accompanying progressive adaptation to aquatic niches and conservative features informing on phylogenetic identity. Systematic evaluation will reveal the neurosensory developments that facilitated these Mesozoic ecological success stories in aquatic environments
Towards improved socio-economic assessments of ocean acidification’s impacts
Ocean acidification is increasingly recognized as a component of global change that could have a wide range of impacts on marine organisms, the ecosystems they live in, and the goods and services they provide humankind. Assessment of these potential socio-economic impacts requires integrated efforts between biologists, chemists, oceanographers, economists and social scientists. But because ocean acidification is a new research area, significant knowledge gaps are preventing economists from estimating its welfare impacts. For instance, economic data on the impact of ocean acidification on significant markets such as fisheries, aquaculture and tourism are very limited (if not non-existent), and non-market valuation studies on this topic are not yet available. Our paper summarizes the current understanding of future OA impacts and sets out what further information is required for economists to assess socio-economic impacts of ocean acidification. Our aim is to provide clear directions for multidisciplinary collaborative research
Protection against oxidation, by CVD or SPS coatings of hafnium carbide and silicon carbide, on carbon/carbon composites
protection of carbon/carbon composites against oxidation at high temperatures. However HfC and most of metallic carbides present a non stoechiometric composition with carbon vacancies. As a consequence, the oxidation resistance is poor at low temperatures (500-1000°C). In order to overcome this main drawback the HfC can be associated with silicon carbide (SiC) presenting a better oxidation resistance at lower temperatures.
Two coating routes have been studied; the first one is the Chemical Vapour Deposition which enables to obtain very thin coatings and the second one is the Spark Plasma Sintering technique which permits to get new microstructures of coatings.
On first hand, this study describes the CVD conditions for the deposition of HfC from the metallic hafnium pellets to get hafnium chlorides followed by the reduction of the chlorides by H2 and the deposition of HfC with the methane as carbon precursor. This enables to get an alternated multilayer microstructure made of a first layer of SiC on top of which the first layer of HfC is deposited and so on to a ten alternated layer deposit [1].
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FAO/WHO GIFT (Global Individual Food consumption data Tool): a global repository for harmonised individual quantitative food consumption studies
Knowing who eats what, understanding the various eating habits of different population groups, according to the geographical area, is critical to develop evidence-based policies for nutrition and food safety. The FAO/WHO Global Individual Food consumption data Tool (FAO/WHO GIFT) is a novel open-access online platform, hosted by FAO and supported by WHO, providing access to harmonised individual quantitative food consumption (IQFC) data, especially in low- and middle-income countries (LMIC). FAO/WHO GIFT is a growing repository, which will serve as the global FAO/WHO hub to disseminate IQFC microdata. Currently five datasets from LMIC are available for dissemination, and an additional fifty datasets will be made available by 2022. To facilitate the use of these data by policy makers, ready-to-use food-based indicators are provided for an overview of key data according to population segments and food groups. FAO/WHO GIFT also provides an inventory of existing IQFC data worldwide, which currently contains detailed information on 188 surveys conducted in seventy-two countries. In order for end-users to be able to aggregate the available data, all datasets are harmonised with the European Food Safety Authority's food classification and description system FoodEx2 (modified for global use). This harmonisation is aimed at enhancing the consistency and reliability of nutrient intake and dietary exposure assessments. FAO/WHO GIFT is developed in synergy with other global initiatives aimed at increasing the quality, availability and use of IQFC data in LMIC to enable evidence-based decision-making and policy development for better nutrition and food safety
Flavonoids in phylloclades discriminate endemic Semele androgyna chemotypes from Madeira
Thirty-five randomly-collected Semele androgyna Kunth
samples were screened by RP-HPLC for their phenolic
composition. Fraction analysis allowed the detection of
17 different compounds. According to their retention
times and UV spectra obtained by diode array analysis,
these phenolics represent three classes: phenolic
acids, flavones and flavonols. Co-chromatography with
specific standards enabled identification of quercetin,
rutin and quercitrin in Semele tissues for the first time.
Polymorphism based on phenolic composition was
evaluated using multivariate analysis and showed four
distinct S. androgyna clusters. This polymorphism was
not associated with morphological diversity or different
in ambient light intensities. Biochemical differentiation
is thus present in this species. The application of
multivariate analysis techniques to RP-HPLC data has
allowed the classification of samples into two groups,
previously proposed on the basis of morphological and
cytotaxonomical information. Therefore, the use of
phenolics as chemotaxonomic markers in Semele is
highly recommended because of its diagnostic value,
even at a subspecies level. Discriminant canonical
analysis and Mahalanobis distances confirmed these
clusters as recognisable chemosystematic units.
However, these units do not support the separation of S.
pterygophora.The Portuguese Foundation for Science and
Technology (FCT) funded this work through the Centre of Macaronesian
Studies (CEM). The authors are grateful to the Madeiran Centre of
Science and Technology (CITMA), the Berardo Foundation and
European Social Funding for financial assistance given during execution
of this work. The assistance rendered by Mr Rogério Correia during field
collection is gratefully acknowledged.info:eu-repo/semantics/publishedVersio
Mechanical response of plectonemic DNA: an analytical solution
We consider an elastic rod model for twisted DNA in the plectonemic regime.
The molecule is treated as an impenetrable tube with an effective, adjustable
radius. The model is solved analytically and we derive formulas for the contact
pressure, twisting moment and geometrical parameters of the supercoiled region.
We apply our model to magnetic tweezer experiments of a DNA molecule subjected
to a tensile force and a torque, and extract mechanical and geometrical
quantities from the linear part of the experimental response curve. These
reconstructed values are derived in a self-contained manner, and are found to
be consistent with those available in the literature.Comment: 14 pages, 4 figure
Invasive micropapillary carcinoma of the breast overexpresses MUC4 and is associated with poor outcome to adjuvant trastuzumab in HER2-positive breast cancer
Invasive micropapillary carcinoma of the breast (IMPC) is a histological tumor variant that occurs with low frequency characterized by an inside-out formation of tumor clusters with a pseudopapillary arrangement. IMPC is an aggressive tumor with poor clinical outcome. In addition, this histological subtype usually expresses human epidermal growth factor receptor 2 (HER2) which also correlates with a more aggressive tumor. In this work we studied the clinical significance of IMPC in HER2-positive breast cancer patients treated with adjuvant trastuzumab. We also analyzed mucin 4 (MUC4) expression as a novel biomarker to identify IMPC.Fil: Mercogliano, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Inurrigarro, Gloria. Sanatorio Mater Dei Hermanas de María de Schoenstatt; ArgentinaFil: de Martino, Mara. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Venturutti, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Rivas, Martin Alfredo. Cornell University; Estados UnidosFil: Cordo Russo, Rosalia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Proietti Anastasi, Cecilia Jazmín. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Fernandez, Elmer Andres. Universidad Católica de Córdoba; ArgentinaFil: Frahm, Isabel. Sanatorio Mater Dei Hermanas de María de Schoenstatt; ArgentinaFil: Barchuk, Sabrina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos ; ArgentinaFil: Allemand, Daniel H.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos ; ArgentinaFil: Figurelli, Silvina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos ; ArgentinaFil: Gil Deza, Ernesto. Instituto Oncológico Henry Moore; ArgentinaFil: Ares, Sandra. Instituto Oncológico Henry Moore; ArgentinaFil: Gercovich, Felipe G.. Instituto Oncológico Henry Moore; ArgentinaFil: Cortese, Eduardo. Ministerio de Defensa. Fuerza Aérea Argentina. Hospital Aeronáutico Central ; ArgentinaFil: Amasino, Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Guzmán, Pablo. Universidad de La Frontera; ChileFil: Roa, Juan C.. Universidad de La Frontera; ChileFil: Elizalde, Patricia Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Schillaci, Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin
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