988 resultados para 2003-09-BS


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Biogenic calcification is influenced by the concentration of available carbonate ions. The recent confirmation of this for hermatypic corals has raised concern over the future of coral reefs because [CO3] is a decreasing function of increasing pCO2 in the atmosphere. As one of the overriding features of coral reefs is their diversity, understanding the degree of variability between species in their ability to cope with a change in [CO3] is a priority. We cultured four phylogenetically and physiologically different species of hermatypic coral (Acropora verweyi, Galaxea fascicularis, Pavona cactus and Turbinaria reniformis) under 'normal' (280 µmol/kg) and 'low' (140 µmol/kg) carbonate-ion concentrations. The effect on skeletogenesis was investigated quantitatively (by calcification rate) and qualitatively (by microstructural appearance of growing crystalline fibres using scanning electron microscopy (SEM)). The 'low carbonate' treatment resulted in a significant suppression of calcification rate and a tendency for weaker crystallization at the distal tips of fibres. However, while the calcification rate was affected uniformly across species (13-18% reduction), the magnitude of the microstructural response was highly species specific: crystallization was most markedly affected in A. verweyi and least in T. reniformis. These results are discussed in relation to past records and future predictions of carbonate variability in the oceans.

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The phenomenon of the informality has been common in the quarrels that involve Sciences Social and Human. First for not corresponding to a temporary and isolated phenomenon, and on the other hand for dealing with a presente situation in the majority of the Brazilian urban centers. In Cuiabá municipality, the alternative commerce appears as a social answer to the problems caused for the economic crisis of the country and seems to be deep-rooted to the urban landscape. This assignment angles was the street peddlers, in special that ones who develop their in a specific location on lowered of Cuiabá. Researches pretending to fill a blank of information about this subject involve theoritical and empirical levels. The theory searched to raise in a generalized manner given pertinent the informality and the pratical level through field research searched to analyze excellent aspects on the economic and occupational situation of a composed sample for two hundred and theree workers who develope the pratical one of the informal commerce in Shopping Popular in Cuiaba/MT. The analysis of gotten data alllowed to appreciate some excellent aspects with regard to the activity os the peddler, as: origni, formation, income, perspectives with regard to activity among others. In las analysis it still alllowed to verify the factors that condition the permanence these workers in this type of informal activity

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The phenomenon of the informality has been common in the quarrels that involve Sciences Social and Human. First for not corresponding to a temporary and isolated phenomenon, and on the other hand for dealing with a presente situation in the majority of the Brazilian urban centers. In Cuiabá municipality, the alternative commerce appears as a social answer to the problems caused for the economic crisis of the country and seems to be deep-rooted to the urban landscape. This assignment angles was the street peddlers, in special that ones who develop their in a specific location on lowered of Cuiabá. Researches pretending to fill a blank of information about this subject involve theoritical and empirical levels. The theory searched to raise in a generalized manner given pertinent the informality and the pratical level through field research searched to analyze excellent aspects on the economic and occupational situation of a composed sample for two hundred and theree workers who develope the pratical one of the informal commerce in Shopping Popular in Cuiaba/MT. The analysis of gotten data alllowed to appreciate some excellent aspects with regard to the activity os the peddler, as: origni, formation, income, perspectives with regard to activity among others. In las analysis it still alllowed to verify the factors that condition the permanence these workers in this type of informal activity

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The South Carolina Transportation Infrastructure Bank reports to the Office of State Budget its annual accountability report that includes an executive summary, organizational profile including leadership system, program descriptions and budgets, and program results.

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A series of 7 cerium double-decker complexes with various tetrapyrrole ligands including porphyrinates, phthalocyaninates, and 2,3-naphthalocyaninates have been prepared by previously described methodologies and characterized with elemental analysis and a range of spectroscopic methods. The molecular structures of two heteroleptic \[(na)phthalocyaninato](porphyrinato) complexes have also been determined by X-ray diffraction analysis which exhibit a slightly distorted square antiprismatic geometry with two domed ligands. Having a range of tetrapyrrole ligands with very different electronic properties, these compounds have been systematically investigated for the effects of ligands on the valence of the cerium center. On the basis of the spectroscopic (UV−vis, near-IR, IR, and Raman), electrochemical, and structural data of these compounds and compared with those of the other rare earth(III) counterparts reported earlier, it has been found that the cerium center adopts an intermediate valence in these complexes. It assumes a virtually trivalent state in cerium bis(tetra-tert-butylnaphthalocyaninate) as a result of the two electron rich naphthalocyaninato ligands, which facilitate the delocalization of electron from the ligands to the metal center. For the rest of the cerium double-deckers, the cerium center is predominantly tetravalent. The valences (3.59−3.68) have been quantified according to their LIII-edge X-ray absorption near-edge structure (XANES) profiles.

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The effect of mechanochemical activation upon the intercalation of formamide into a high-defect kaolinite has been studied using a combination of X-ray diffraction, thermal analysis, and DRIFT spectroscopy. X-ray diffraction shows that the intensity of the d(001) spacing decreases with grinding time and that the intercalated high-defect kaolinite expands to 10.2 A. The intensity of the peak of the expanded phase of the formamide-intercalated kaolinite decreases with grinding time. Thermal analysis reveals that the evolution temperature of the adsorbed formamide and loss of the inserting molecule increases with increased grinding time. The temperature of the dehydroxylation of the formamide-intercalated high-defect kaolinite decreases from 495 to 470oC with mechanochemical activation. Changes in the surface structure of the mechanochemically activated formamide-intercalated high-defect kaolinite were followed by DRIFT spectroscopy. Fundamentally the intensity of the high-defect kaolinite hydroxyl stretching bands decreases exponentially with grinding time and simultaneously the intensity of the bands attributed to the OH stretching vibrations of water increased. It is proposed that the mechanochemical activation of the high-defect kaolinite caused the conversion of the hydroxyls to water which coordinates the kaolinite surface. Significant changes in the infrared bands assigned to the hydroxyl deformation and amide stretching and bending modes were observed. The intensity decrease of these bands was exponentially related to the grinding time. The position of the amide C&unknown;O vibrational mode was found to be sensitive to grinding time. The effect of mechanochemical activation of the high-defect kaolinite reduces the capacity of the kaolinite to be intercalated with formamide.

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Deficiencies in the design and operation of office buildings can give rise to high social, environmental and economic (triple bottom line) costs. As a result, there are significant pressures and incentives to develop ‘smart building’ technologies that can facilitate improved indoor environment quality (IEQ), and more energy efficient operation of office buildings. IEQ indicators include lighting, ventilation, thermal comfort, indoor air quality and noise. In response to this, the CRC for Construction Innovation commissioned a six-month scoping study (Project no. 2002-043) to examine how different technologies could be used to improve the ‘triple bottom line’ for office buildings. The study was supported by three industry partners, Bovis Lend Lease, Arup, and The Queensland Department of Public Works. The objective of the study was to look at the history, trends, drivers, new technologies and potential application areas related to the operation of healthy and efficient office buildings. The key output from the study was a recommendation for a prototype system for intelligent monitoring and control of an office environment, based on identified market, technical and user requirements and constraints.

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The innovation diffusion and knowledge management literature strongly supports the importance of communities of practice (COP) for enabling knowledge about how to use and adopt innovation initiatives. One of the most powerful tools for innovation diffusion is word-of-mouth wisdom from committed individuals who mentor and support each other. Close proximity for face-to-face interaction is highly effective, however, many organisations are geographically dispersed with projects being virtual linked sub-organisations using ICT to communicate. ICT has also introduced a useful facilitating technology for developing knowledge networks. This paper presents findings from a research program concentrating on ICT innovation diffusion in the Australian construction industry. One way in which ICT diffusion is taking place was found to be through within-company communities of practice. We undertook in-depth unstructured interviews with three of the major 10 to 15 contractors in Australia to discuss their ICT diffusion strategies. We discovered that in all three cases,within company networked communities of practice was a central strategy. Further, effective diffusion of ICT groupware tools can be critical in developing COP where they are geographically dispersed.

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This paper examines knowledge management and innovation in the Australian Construction Industry. A conceptual model is presented, based upon analysis of the literature and a series of preliminary construction industry interviews. Extensive knowledge management (KM) research has focused upon types of knowledge contained within specific organizational settings. However, we argue that a crucial missing link in KM research concerns the interface between flows of knowledge from external sources of innovations and its channelization in and out, and between organizations. This interface, regulating and facilitating knowledge from external sources of innovation into the organisation, operates under the influence of two main forces visualized as “pulling” and “pushing” forces in the model presented in this paper. The premise of the model lies in a hypothesis that as an organization changes itself into a more mature, learning organization (LO) over time, knowledge flows into it through “pull” rather than “push” forces. We conclude that a successful knowledge management initiative installs a learning and knowledge sharing culture, which is easily adaptable to new learning offering little resistance to new knowledge that flows into the organisation. The model bridges the gap between research and its application in construction practice.

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Previous studies have reported that patients with schizophrenia demonstrate impaired performance during working memory (WM) tasks. The current study aimed to determine whether WM impairments in schizophrenia are accompanied by reduced slow wave (SW) activity during on-line maintenance of mnemonic information. Event-related potentials were obtained from patients with schizophrenia and well controls as they performed a visuospatial delayed response task. On 50% of trials, a distractor stimulus was introduced during the delay. Compared with controls, patients with schizophrenia produced less SW memory negativity, particularly over the right hemisphere, together with reduced frontal enhancement of SW memory negativity in response to distraction. The results indicate that patients with schizophrenia generate less maintenance phase neuronal activity during WM performance, especially under conditions of distraction.

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In this paper, we develop the switching controller presented by Lee et al. for the pose control of a car-like vehicle, to allow the use of an omnidirectional vision sensor. To this end we incorporate an extension to a hypothesis on the navigation behaviour of the desert ant, cataglyphis bicolor, which leads to a correspondence free landmark based vision technique. The method we present allows positioning to a learnt location based on feature bearing angle and range discrepancies between the robot's current view of the environment, and that at a learnt location. We present simulations and experimental results, the latter obtained using our outdoor mobile platform.

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In this paper we describe a low-cost flight control system for a small (60 class) helicopter which is part of a larger project to develop an autonomous flying vehicle. Our approach differs from that of others in not using an expensive inertial/GPS sensing system. The primary sensors for vehicle stabilization are a low-cost inertial sensor and a pair of CMOS cameras. We describe the architecture of our flight control system, the inertial and visual sensing subsystems and present some flight control results.

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The ideal dermal matrix should be able to provide the right biological and physical environment to ensure homogenous cell and extracellular matrix (ECM) distribution, as well as the right size and morphology of the neo-tissue required. Four natural and synthetic 3D matrices were evaluated in vitro as dermal matrices, namely (1) equine collagen foam, TissuFleece®, (2) acellular dermal replacement, Alloderm®, (3) knitted poly(lactic-co-glycolic acid) (10:90)–poly(-caprolactone) (PLGA–PCL) mesh, (4) chitosan scaffold. Human dermal fibroblasts were cultured on the specimens over 3 weeks. Cell morphology, distribution and viability were assessed by electron microscopy, histology and confocal laser microscopy. Metabolic activity and DNA synthesis were analysed via MTS metabolic assay and [3H]-thymidine uptake, while ECM protein expression was determined by immunohistochemistry. TissuFleece®, Alloderm® and PLGA–PCL mesh supported cell attachment, proliferation and neo-tissue formation. However, TissuFleece® contracted to 10% of the original size while Alloderm® supported cell proliferation predominantly on the surface of the material. PLGA–PCL mesh promoted more homogenous cell distribution and tissue formation. Chitosan scaffolds did not support cell attachment and proliferation. These results demonstrated that physical characteristics including porosity and mechanical stability to withstand cell contraction forces are important in determining the success of a dermal matrix material.