990 resultados para 333.918


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Canna tandilensis is proposed as a species new to science. Plants grow wild terrestrial, in rocky places exposed to solar radiation forming dense colonies whose individuals of small to medium length, produce reduced inflorescences with large and few yellow to bright orange flowers and narrow and reflexed staminodes. The specific epithet refers to the city of Tandil at the south of Buenos Aires Province where the holotype comes from. It is related to other species having reduced inflorescences, narrow leaves and staminodes, and nectar guides in androecium pieces such as C. lineata. A detailed description of the new species is given, along with a study of the morphological vegetative and floral characters. These characters were compared with those from two other species C. glauca and C. lineata. According to these new evidences two groups of similar species of the genus are suggested. The number of species surveyed until now in Argentina rises to sixteen.

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Phytoplankton observation is the product of a number of trade-offs related to sampling processes, required level of diversity and size spectrum analysis capabilities of the techniques involved. Instruments combining the morphological and high-frequency analysis for phytoplankton cells are now available. This paper presents an application of the automated high-resolution flow cytometer Cytosub as a tool for analysing phytoplanktonic cells in their natural environment. High resolution data from a temporal study in the Bay of Marseille (analysis every 30 min over 1 month) and a spatial study in the Southern Indian Ocean (analysis every 5 min at 10 knots over 5 days) are presented to illustrate the capabilities and limitations of the instrument. Automated high-frequency flow cytometry revealed the spatial and temporal variability of phytoplankton in the size range 1−∼50 μm that could not be resolved otherwise. Due to some limitations (instrumental memory, volume analysed per sample), recorded counts could be statistically too low. By combining high-frequency consecutive samples, it is possible to decrease the counting error, following Poisson’s law, and to retain the main features of phytoplankton variability. With this technique, the analysis of phytoplankton variability combines adequate sampling frequency and effective monitoring of community changes.

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The review compiles, for the first time, data on the communities at 62 shallow-water hydrothermal vent and cold seep sites. ‘Shallow sites’ are defined as sites no deeper than 200 m. The communities at these sites are also compared with communities in reducing sediments at similar depths. Below 200 m, vent and seep obligate species tend to dominate the fauna living in areas where reducing fluids are released from the seabed. At the shallow sites, vent and seep obligate species of fauna are rare, only eight having being reported from shallow vents. No definite seep obligates have been found. Shallow vents and seeps are colonized by communities that consist of a subset of the background fauna, especially those species that are less sensitive to hydrogen sulphide toxicity. Conversely the zones directly surrounding shallow vent and seeps sites with varied topography, substrate type and food supply, often have a higher species diversity than the background area. The reasons for these differences are discussed.

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Se estudian comparativamente los pastizales pioneros vivaces de los suelos serpentínicos de Galicia y del nordeste de Portugal, describiéndose la asociación Sagino merinoi-Plantagínetum radicatae nova.

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The vegetal population of Isla Grosa, island located in the neighbourhood of Mar Menos (Mediterranean Sea), is studies. It is registered the presence of the association Mayteno-Periplocetum. Likewise a registrer of other species is given, being this the first vegetal contribution to this volcanic island.

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Xanthoria parietina, common foliose lichen, growing in its natural habitat, was analysed for the concentration of five heavy metals (Fe, Cr, Zn, Pb and Cu) from different forest sites of North East of Morocco (Kenitra, Sidi Boughaba, Mkhinza, Ceinture Verte near Temara city, Skhirate, Bouznika and Mohammedia). The quantification was carried out by inductively coupled plasma - atomic emission spectrometry (ICP-AES). Results were highly significant p<0,001. The concentration of metals is correlated with the vehicular activity and urbanization. The total metal concentration is highest at the Kenitra area, followed by Ceinture Verte site near Temara city, which experience heavy traffic throughout the year. Scanning electron microscopy (SEM) of particulate matter on lichen of Xanthoria parietina was assessed as a complementary technique to wet chemical analysis for source apportionment of airborne contaminant. Analysis revealed high level of Cu, Cr, Zn and Pb in samples near roads.  

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We present descriptions of a new order (Ranunculo cortusifolii-Geranietalia reuteri and of a new alliance (Stachyo lusitanicae-Cheirolophion sempervirentis) for the herbaceous fringe communities of Macaronesia and of the southwestern Iberian Peninsula, respectively. A new alliance, the Polygalo mediterraneae-Bromion erecti (mesophilous post-cultural grasslands), was introduced for the Peninsular Italy. We further validate and typify the Armerietalia rumelicae (perennial grasslands supported by nutrient-poor on siliceous bedrocks at altitudes characterized by the submediterranean climate of central-southern Balkan Peninsula), the Securigero-Dasypyrion villosae (lawn and fallow-land tall-grass annual vegetation of Italy), and the Cirsio vallis-demoni-Nardion (acidophilous grasslands on siliceous substrates of the Southern Italy). Nomenclatural issues (validity, legitimacy, synonymy, formal corrections) have been discussed and clarified for the following names: Brachypodio-Brometalia, Bromo pannonici-Festucion csikhegyensis, Corynephoro-Plantaginion radicatae, Heleochloion, Hieracio-Plantaginion radicatae, Nardetea strictae, Nardetalia strictae, Nardo-Callunetea, Nardo-Galion saxatilis, Oligo-Bromion, Paspalo-Heleochloetalia, Plantagini-Corynephorion and Scorzoneret alia villosae. 

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Measures of prevention and control against polycyclic aromatic hydrocarbons (PAHs) focus on an official food control, a code of best practice to reduce PAHs levels by controlling industry and in the development of a chemopreventive strategy. Regulation (EU) 835/2011 establishes maximum levels of PAHs for each food group. In addition, Regulations (EU) 333/2007 and 836/2011 set up the methods of sampling and analysis for its official control. Scientific studies prove that the chemopreventive strategy is effective against these genotoxic compounds effects. Most chemopreventive compounds studied with proven protective effects against PAHs are found in fruit and vegetables.

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Se analizan y describen las principales líneas de trabajo de la Web Semántica en el ámbito de los archivos de televisión. Para ello, se analiza y contextualiza la web semántica desde una perspectiva general para posteriormente analizar las principales iniciativas que trabajan con lo audiovisual: Proyecto MuNCH, Proyecto S5T, Semantic Television y VideoActive.

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The use of social work case files as an important research resource is being threatened by the increasing regulation of both the research process and access to personal identifiable information. While these developments can be seen as a reaction to specific incidents of inappropriate research and the misuse of personal information, it is argued that the pendulum has swung too far the other way, and in seeking to protect the rights of vulnerable individuals, the lives of these same individuals may go unstudied with the consequence that they receive less appropriate services. Drawing upon the current research of the authors, this article explores the difficulties encountered in gaining access to social work case files for research purposes without the explicit consent of service users and highlights the uncertainty surrounding this issue. Suggestions are made for improvements in the situation.

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