32 resultados para Rare plants
em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain
Resumo:
An analysis is carried out in a sample of 738 industrial plants of the determining factors in the use of internal promotion of blue-collar workers to middle managers and skilled technicians as against their external recruitment. The use of internal promotion is positively correlated with variables indicative of the efforts made by plants to measure employees' skills, and to a lesser extent, with the level of specificity of investments in human capital made by blue-collar workers. Contrary to what was expected, variables related with the use and efficiency of other incentive systems have no significant influence on the increased or decreased use of internal promotion. These results are initial evidence that internal promotions are used to protect and favour specific investments, especially those made by firms in order to discover their workers' skills.
Resumo:
The plant cell wall is a strong fibrillar network that gives each cell its stable shape. It is constituted by a network of cellulose microfibrils embedded in a matrix of polysaccharides, such as xyloglucans. To enlarge, cells selectively loosen this network. Moreover, there is a pectin-rich intercellular material, the middle lamella, cementing together the walls of adjacent plant cells. Xyloglucan endotransglucosylase/hydrolases (XTHs) are a group of enzymes involved in the reorganisation of the cellulose-xyloglucan framework by catalysing cleavage and re-ligation of the xyloglucan chains in the plant cell wall, and are considered cell wall loosening agents. In the laboratory, it has been isolated and characterised a XTH gene, ZmXTH1, from an elongation root cDNA library of maize. To address the cellular function of ZmXTH1, transgenic Arabidopsis thaliana plants over-expressing ZmXTH1 (under the control of the CaMV35S promoter) were generated. The aim of the work performed was therefore the characterisation of these transgenic plants at the ultrastructural level, by transmission electron microscopy (TEM).The detailed cellular phenotype of transgenic plants was investigated by comparing ultra-thin transverse sections of basal stem of 5-weeks old plants of wild type (Col 0) and 35S-ZmXTH1 Arabidopsis plants. Transgenic plants show modifications in the cell walls, particularly a thicker middle lamella layer with respect the wild type plants, supporting the idea that the overexpression of ZmXTH1 could imply a pronounced wall-loosening. In sum, the work carried out reinforces the idea that ZmXTH1 is involved in the cell wall loosening process in maize.
Resumo:
Rare Disease Video Portal (RD Video) is a portal web where contains videos from Youtube including all details from 12 channels of Youtube.
Resumo:
The aim of this book is to survey on different Land Use Planning and safety approaches in vicinity of industrial plants. As this research is associated with three broad fields of Land Use Planning, safety and security, the set principle is to avoid unnecessary and over detailed information, but including the useful ones to provide a comprehensive resource which can be applicable for several purposes. Besides, the proposed method, which is explained in Chapter 7, can initiate a new field for future of Land Use Planning in vicinity of industrial plants.
Resumo:
L’objectiu principal és presentar un nou prototipus d’eina per al disseny de les plantes de tractament d’aigües residuals utilitzant models mecànics dinàmics quantificant la incertesa
Resumo:
Tapinoma pygmaeum is an ant known from seven localities. Five of them are in theprovince of Girona (Spain). The apparent rarity and skewed distribution of this species isprobably an artifact due to the confussion, in field samplings, with a similar speciesPlagiolepis pygmaea
Resumo:
Correspondence analysis, when used to visualize relationships in a table of counts(for example, abundance data in ecology), has been frequently criticized as being too sensitiveto objects (for example, species) that occur with very low frequency or in very few samples. Inthis statistical report we show that this criticism is generally unfounded. We demonstrate this inseveral data sets by calculating the actual contributions of rare objects to the results ofcorrespondence analysis and canonical correspondence analysis, both to the determination ofthe principal axes and to the chi-square distance. It is a fact that rare objects are oftenpositioned as outliers in correspondence analysis maps, which gives the impression that theyare highly influential, but their low weight offsets their distant positions and reduces their effecton the results. An alternative scaling of the correspondence analysis solution, the contributionbiplot, is proposed as a way of mapping the results in order to avoid the problem of outlying andlow contributing rare objects.
Resumo:
The control and prediction of wastewater treatment plants poses an important goal: to avoid breaking the environmental balance by always keeping the system in stable operating conditions. It is known that qualitative information — coming from microscopic examinations and subjective remarks — has a deep influence on the activated sludge process. In particular, on the total amount of effluent suspended solids, one of the measures of overall plant performance. The search for an input–output model of this variable and the prediction of sudden increases (bulking episodes) is thus a central concern to ensure the fulfillment of current discharge limitations. Unfortunately, the strong interrelationbetween variables, their heterogeneity and the very high amount of missing information makes the use of traditional techniques difficult, or even impossible. Through the combined use of several methods — rough set theory and artificial neural networks, mainly — reasonable prediction models are found, which also serve to show the different importance of variables and provide insight into the process dynamics
Resumo:
This paper presents a case study that explores the advantages that can be derived from the use of a design support system during the design of wastewater treatment plants (WWTP). With this objective in mind a simplified but plausible WWTP design case study has been generated with KBDS, a computer-based support system that maintains a historical record of the design process. The study shows how, by employing such a historical record, it is possible to: (1) rank different design proposals responding to a design problem; (2) study the influence of changing the weight of the arguments used in the selection of the most adequate proposal; (3) take advantage of keywords to assist the designer in the search of specific items within the historical records; (4) evaluate automatically thecompliance of alternative design proposals with respect to the design objectives; (5) verify the validity of previous decisions after the modification of the current constraints or specifications; (6) re-use the design records when upgrading an existing WWTP or when designing similar facilities; (7) generate documentation of the decision making process; and (8) associate a variety of documents as annotations to any component in the design history. The paper also shows one possible future role of design support systems as they outgrow their current reactive role as repositories of historical information and start to proactively support the generation of new knowledge during the design process
Resumo:
The Virulundo carbonatite in Angola, one of the biggest in the world, contains pyrochlore as an accessory mineral in all of the carbonatite units (calciocarbonatites, ferrocarbonatites, carbonatite breccias, trachytoids). The composition of the primary pyrochlore crystals is very close to fluornatrocalciopyrochlore in all these units. High-temperature hydrothermal processes caused the pseudomorphic replacement of the above crystals by a second generation of pyrochlore, characterized by lower F and Na contents. Low-temperature hydrothermal replacement of the above pyrochlores, associated with production of quartz-carbonates-fluorite veins, controled the development of a third generation of pyrochlore, characterized by high Sr contents. Finally, supergene processes produced the development of a secondary paragenesis in the carbonatite, consisting in late carbonates, goethite, hollandite and REE minerals (mainly synchysite-(Ce), britholite-(Ce), britholite-(La), cerite-(Ce)). Separation of Ce from the other REE was allowed by oxidizing conditions. Therefore, Ce4+ was also incorporated into a late generation of pyrochlore, which is also strongly enriched in Ba and strongly depleted in Ca and Na
Resumo:
Palaeobotany applied to freshwater plants is an emerging field of palaeontology. Hydrophytic plants reveal evolutionary trends of their own, clearly distinct from those of the terrestrial and marine flora. During the Precambrian, two groups stand out in the fossil record of freshwater plants: the Cyanobacteria (stromatolites) in benthic environments and the prasinophytes (leiosphaeridian acritarchs) in transitional planktonic environments. During the Palaeozoic, green algae (Chlorococcales, Zygnematales, charophytes and some extinct groups) radiated and developed the widest range of morphostructural patterns known for these groups. Between the Permian and Early Cretaceous, charophytes dominated macrophytic associations, with the consequence that over tens of millions of years, freshwater flora bypassed the dominance of vascular plants on land. During the Early Cretaceous, global extension of the freshwater environments is associated with diversification of the flora, including new charophyte families and the appearance of aquatic angiosperms and ferns for the first time. Mesozoic planktonic assemblages retained their ancestral composition that was dominated by coenobial Chlorococcales, until the appearance of freshwater dinoflagellates in the Early Cretaceous. In the Late Cretaceous, freshwater angiosperms dominated almost all macrophytic communities worldwide. The Tertiary was characterised by the diversification of additional angiosperm and aquatic fern lineages, which resulted in the first differentiation of aquatic plant biogeoprovinces. Phytoplankton also diversified during the Eocene with the development of freshwater diatoms and chrysophytes. Diatoms, which were exclusively marine during tens of millions of years, were dominant over the Chlorococcales during Neogene and in later assemblages. During the Quaternary, aquatic plant communities suffered from the effects of eutrophication, paludification and acidification, which were the result of the combined impact of glaciation and anthropogenic disturbance.
Resumo:
The low-temperature isothermal magnetization curves, M(H), of SmCo4 and Fe3Tb thin films are studied according to the two-dimensional correlated spin-glass model of Chudnovsky. We have calculated the magnetization law in approach to saturation and shown that the M(H) data fit well the theory at high and low fields. In our fit procedure we have used three different correlation functions. The Gaussian decay correlation function fits well the experimental data for both samples.
Resumo:
Additions to the vascular flora of the Cadí-Moixeró Natural Park and neighbouring Pre-Pyrenean areas (eastern Iberian Pyrenees) We present about fifty contributions to the catalogue of the vascular flora of the mentioned area, published in 2003. Among the taxa reported, 21 correspond to novelties found in our own field observations or in the literature. We highlight the first records for the Eastern Iberian Pre-Pyrenees of Meconopsis cambrica (L.) Vig. and Omalotheca hoppeana (Koch) Schulz Bip. and F.W. Schulz. Other data refer to rare taxa already included in the catalogue, such as Gagea lutea (L.) Ker Gawl., G. reverchonii Degen, Lappula deflexa (Wahlenb.) Garcke and Minuartia villarii (Balb.) Wilczek and Chenevard.
Resumo:
Catalogue of endemic, rare or threatened vascular plants in Catalonia. I. Endemic taxa. This is the first of a set of papers devoted to rare or threatened plants in Catalonia. We list 279 specific or subspecific taxa which are in a broad sense endemic to the northeastern part of the Iberian Peninsula. We assess them with regard to their conservation status according to IUCN criteria. Assignment of these taxa to established categories has led to the following results: 6 taxa critically endangered (CR), 5 endangered (EN), 32 vulnerable (VU), 5 near threatened (LR nt). 84 least concern (LR lc), 116 not threatened (NT) and 31 data deficient (DD). The small number of taxa that enjoy legal protection in comparison with the number of threatened plants is emphasized. Key words: Endemic plants, Catalonia, Plant conservation, UICN categories.