Adsorció de crom (VI) i crom (III) en solució amb closca de cranc

En l’eliminació del crom en suspensió de les aigües residuals de les indústries es realitzen dos processos: una precipitació en medi àcid on es redueix el crom (VI) a crom (III) en què s’elimina la major part del crom, i el següent tractament es fa per bescanvi iònic o per adsorció. Els adsorbents emprats actualment tenen un elevat cost i s’està estudiant nous adsorbents, com a substituts dels tradicionals, de baix cost. Dins d’aquest adsorbents de baix cost es troben els bioadsorbents, biomaterials amb gran capacitat d’adsorció. L’objectiu del projecte es va centrar en l’estudi de l’adsorció de crom trivalent i hexavalent en solucions aquoses utilitzant com a adsorbent el residu industrial de closca de cranc, provinent d’una indústria alimentària de barretes de cranc

O atendimento educacional especializado para o aluno com paralisia cerebral em uma escola municipal do Nordeste Brasileiro

Ações em torno da efetivação da política de Educação Inclusiva no contexto brasileiro tem sido uma realidade constatada no âmbito da legislação, prevendo ações de qualidade que favoreçam o acesso e a permanência de alunos com deficiência no ensino regular. Dentre essas ações, destaca-se a implantação das Salas de Recursos Multifuncionais (SRMF), visando à garantia do Atendimento Educacional Especializado (AEE). Nessa perspectiva, a presente pesquisa se propõe a descrever o AEE a um aluno com paralisia cerebral em uma escola municipal do Nordeste brasileiro e, também, seus desdobramentos em termos de articulação e atendimento às prerrogativas legais, utilizando-se o método estudo de caso. Participaram do estudo a diretora, a coordenadora pedagógica, as professoras da SRMF e da sala de aula regular, o aluno com paralisia cerebral e a mãe do aluno. Os dados construídos com base em observações e entrevistas, entre outros instrumentos, apontaram, nas análises, para a necessidade de articulação e definição de papéis entre as professoras da Sala de Recursos Multifuncionais e da sala de aula regular, de modo a atender às diretrizes do AEE bem como às ações voltadas para formação continuada e à parceria com a família, com vistas ao fortalecimento do AEE na escola regular.

Leitura e escrita científica : um estudo com alunos do 12º ano de escolaridade de Biologia

Atualmente, os professores de ciências trabalham com alunos que apresentam sérias dificuldades em duas áreas-chave do ensino: a leitura e a escrita. Esta lacuna, dificulta a aquisição e compreensão de determinados conceitos, o que provoca uma necessidade de melhorar os hábitos de leitura e escrita científica. O estudo apresentado neste trabalho pretende analisar a importância da leitura e escrita científica no ensino das ciências no ensino secundário. Objetiva-se que os alunos aprendam e adquiram práticas de escrita e leitura científicas e ainda que despertem para uma parte da ‘ciência real’, como seja o contacto com os artigos elaborados por investigadores, resultantes de trabalhos de pesquisa levados a efeito em instituições ligadas à investigação científica. Para este efeito desenvolveu-se um estudo com alunos de biologia do 12º ano de escolaridade, durante sete meses, em contexto de sala de aula, no qual foi explorada a leitura de artigos científicos e a elaboração de documentos escritos resultantes de uma análise dos mesmos. Os resultados obtidos demonstram que, de uma forma geral, que os conceitos científicos e conteúdos estudados nas aulas de biologia conforme o programa curricular em vigor, foram, com recurso aos artigos científicos, melhor apreendidos e consolidados. Foi ainda verificado um crescente aperfeiçoamento dos hábitos de escrita e leitura dos alunos. Desta forma, pode afirmar-se que o tipo de estratégia apresentada nesta investigação por via da leitura e da escrita promove a compreensão e a retenção dos conteúdos, ou seja, ler e escrever para aprender.

Geochemical changes to dredged canal sediments following land spreading: a review.

This paper brings together some of the recent research on trace metals in dredged sediments, and in particular freshwater canal sediments. Following a description of the general UK background, geochemical processes that affect metal release and retention in dredged canal sediments are considered, particularly the role of redox and sulphur on metal associations, and the use of sequential extraction for the derivation of metal associations in sediments. The review outlines the importance of oxidation on metal-mobility and shows that many studies have illustrated the increase in metal-leachability from sediments during oxidation. Suggestions are given for sediment-testing requirements which should include an examination of both anoxic and oxidised sediment as well as ecotoxicology in order to account for changes to metal-speciation after disposal to land.

Modelling nitrogen fluxes from the land surface to the coastal zone in European systems: the perspective of the INCA project

This paper describes the results and conclusions of the INCA (Integrated Nitrogen Model for European CAtchments) project and sets the findings in the context of the ELOISE (European Land-Ocean Interaction Studies) programme. The INCA project was concerned with the development of a generic model of the major factors and processes controlling nitrogen dynamics in European river systems, thereby providing a tool (a) to aid the scientific understanding of nitrogen transport and retention in catchments and (b) for river-basin management and policy-making. The findings of the study highlight the heterogeneity of the factors and processes controlling nitrogen dynamics in freshwater systems. Nonetheless, the INCA model was able to simulate the in-stream nitrogen concentrations and fluxes observed at annual and seasonal timescales in Arctic, Continental and Maritime-Temperate regimes. This result suggests that the data requirements and structural complexity of the INCA model are appropriate to simulate nitrogen fluxes across a wide range of European freshwater environments. This is a major requirement for the production of coupled fiver-estuary-coastal shelf models for the management of our aquatic environment. With regard to river-basin management, to achieve an efficient reduction in nutrient fluxes from the land to the estuarine and coastal zone, the model simulations suggest that management options must be adaptable to the prevailing environmental and socio-economic factors in individual catchments: 'Blanket approaches' to environmental policy appear too simple. (c) 2004 Elsevier B.V. All rights reserved.

Do construction companies need to match employees' expectations?

Commitment of employees is relatively low in construction. This problem is exasperated by companies inability to attract, motivate, and retain talent that is then often channelled into other more attractive industrial sectors where the prospects, conditions and rewards are perceived to be much higher. The purpose of this study is thus primarily to develop a generic model to maximise employees' engagement, improve their motivation and increase the retention levels. To achieve this aim, the investigation looks into how perceived employment obligations and expectations impact commitment and through that organisational performance. The study is based on the postulations of Luhmann's theory of social systems with communication viewed as a constitutive element of a social system. Consequently expectations of a particular party in an employment relationship are represented in a communicative space requiring the other party's understanding in order to align expectations of both sides in the relationship. Explicitly, alignment of by an employee perceived manager's expectations determines his/ her commitment to fulfil obligations towards the manager. The result of this first stage of research is a conceptual model developed following the substantial supporting evidence in the literature and it forms the framework for mitigation of low commitment, motivation and retention of employees. The model particularly focuses on factors affecting employees' perceived expectations like reneging, incongruence and the process of communication. In the future the model will be validated using empirical data from a combination of observational and enquiry-based research. Once completed, the model will provide a framework for informing Human Resource Management policies with the aim to improve commitment of employees, increase the levels of retention and consequently improve the performance of construction organisations.

Utilisation by ruminants of nitrogen compounds in silage-based diets

This paper considers the various complex changes that occur to nitrogen (N) containing compounds in forages through the processes of ensiling, rumen degradation and microbial synthesis, post-ruminal digestion and absorption and synthesis into milk protein. Particular emphasis is placed on reviewing recent data on the efficiency of utilisation of N-containing compounds in silages by rumen microbes, since low efficiency here is believed to be a major cause of large N losses to the environment on some silage-based diets. Data are reviewed which show that although rumen degradation of N compounds in silage is rapid and extensive, up to 10% of the soluble N can escape the rumen by being associated with the liquid phase. There is now firm evidence that the composition of the amino acids (AAs) absorbed is heavily dependent on the process of ensiling and that witting or use of certain silage additives conserve the initial amino acid profile of the forage. This provides an opportunity to manipulate the amino acid supply to better match demand thus potentially enhancing utilisation. This review confirms that utilisation of the N fractions in grass and legume silages in particular, is poor and the efficiency of microbial protein synthesis (EMPS) is consistently higher on maize silage-based diets. It is concluded that the way in which grass and legume silages in particular are produced and used in the future needs a radical rethink. New research needs to be aimed at enhancing the utilisation of N in the rumen through a better understanding of N/carbohydrate relationships and the ability of forages to supply degraded carbohydrate. Also more emphasis is needed on understanding of the potentially different role of the different N fractions that exist in silages. (C) 2004 Elsevier B.V. All rights reserved.

Improving educational functions in botanic gardens by employing landscape narratives

Landscape narrative, combining landscape and narrative, has been employed to create storytelling layouts and interpretive information in some famous botanic gardens. In order to assess the educational effectiveness of using "landscape narrative" in landscape design, the Heng-Chun Tropical Botanical Garden in Taiwan was chosen as research target for an empirical study. Based on cognitive theory and the affective responses of environmental psychology, computer simulations and video recordings were used to create five themed display areas with landscape narrative elements. Two groups of pupils watched simulated films. The pupils were then given an evaluation test and questionnaire, to determine the effectiveness of the landscape narrative. When the content was well associated and matched with the narrative landscape, the comprehension and retention of content was increased significantly. The results also indicated that visual preference of narrative landscape scenes was increased. This empirical study can be regarded as a successful model of integrating landscape narrative and interpretation practice that can be applied to the design of new theme displays in botanic gardens to improve both the effectiveness of interpretation plans and the visual preference of visitors. (c) 2008 Elsevier B.V. All rights reserved.

The temperature-dependent spectral properties of filter substrate materials in the far-infrared (6-40 mu m)

This paper presents the experimental results on the low temperature absorption and dispersion properties for a variety of frequently used infrared filter substrate materials. Index of refraction (n) and transmission spectra are presented for a range of temperatures 300-50 K for the Group IV materials silicon (Si) and germanium (Ge), and Group II-VI materials zinc selenide (ZnSe), zinc sulphide (ZnS) and cadmium telluride (CdTe). (C) 2003 Elsevier B.V. All rights reserved.

Confocal imaging of pseudomonas syringae pv. phaseolicola colony development in bean reveals reduced multiplication of strains containing the genomic island PPHGI-1.

Pseudomonas syringae pv. phaseolicola is the seed borne causative agent of halo blight in the common bean Phaseolus vulgaris. Pseudomonas syringae pv. phaseolicola race 4 strain 1302A contains the avirulence gene hopAR1 (located on a 106-kb genomic island, PPHGI-1, and earlier named avrPphB), which matches resistance gene R3 in P. vulgaris cultivar Tendergreen (TG) and causes a rapid hypersensitive reaction (HR). Here, we have fluorescently labeled selected Pseudomonas syringae pv. phaseolicola 1302A and 1448A strains (with and without PPHGI-1) to enable confocal imaging of in-planta colony formation within the apoplast of resistant (TG) and susceptible (Canadian Wonder [CW]) P. vulgaris leaves. Temporal quantification of fluorescent Pseudomonas syringae pv. phaseolicola colony development correlated with in-planta bacterial multiplication (measured as CFU/ml) and is, therefore, an effective means of monitoring Pseudomonas syringae pv. phaseolicola endophytic colonization and survival in P. vulgaris. We present advances in the application of confocal microscopy for in-planta visualization of Pseudomonas syringae pv. phaseolicola colony development in the leaf mesophyll to show how the HR defense response greatly affects colony morphology and bacterial survival. Unexpectedly, the presence of PPHGI-1 was found to cause a reduction of colony development in susceptible P. vulgaris CW leaf tissue. We discuss the evolutionary consequences that the acquisition and retention of PPHGI-1 brings to Pseudomonas syringae pv. phaseolicola in planta.

Olive oil increases the number of triacylglycerol-rich chylomicron particles compared with other oils: an effect retained when a second standard meal is fed

Background: Compared with the postprandial events after a single meal, different events occur when a second meal is ingested 4–6 h after a first meal. There is a rapid appearance of chylomicrons in the circulation carrying fat ingested with the first meal, with a peak 1 h after the second meal. Objective: Our goal was to examine whether different dietary oils have effects on the storage of triacylglycerol as a result of differences in their digestion, absorption, and incorporation into chylomicrons. Design: A single-blind, randomized, within-subject crossover design was used to study the effects of palm oil, safflower oil, a mixture of fish and safflower oil, and olive oil on postprandial apolipoprotein (apo) B-48, retinyl ester, and triacylglycerol in the Sf > 400 fraction with the use of a sequential meal protocol. Results: For triacylglycerol, retinyl ester, and apo B-48, the time to reach peak concentration was significantly earlier after the second meal than after the first meal (P < 0.005). This was apparent with each of the dietary oils. The pattern of the apo B-48 response differed significantly among the dietary oils, with olive oil resulting in higher concentrations after both meals (P = 0.003). The ratio of triacylglycerol to apo B-48 was significantly lower after olive oil feeding than after feeding with the other oils (P = 0.02). Conclusions: The rapid entry of chylomicrons after the ingestion of a second meal 5 h after a first meal was seen with all of the oils investigated. The short-term ingestion of olive oil produced more chylomicrons than did the other dietary oils, which may have been due to differences in the metabolic handling of olive oil within the gut.

Lack of influence of test meal fatty acid composition on the contribution of intestinally-derived lipoproteins to postprandial lipaemia

The extent and duration of postprandial lipaemia have been linked to risk of CHD but the influence of dietary variables on, and the relative contributions of, exogenous (chylomicron) and endogenous (VLDL) triacylglycerols to the total lipaemic response have not been comprehensively evaluated. In the present study the triacylglycerol, apolipoprotein (apo) B-48 and retinyl ester (RE) responses to three test meals of varying monounsaturated (MUFA) and saturated fatty acid (SFA) content were measured in the triacylglycerol-rich lipoprotein (TRL) fraction of plasma (r ¼ 1·006 g/ml) for 9 h after meal consumption. Fifteen healthy normolipidaemic young men consumed, on separate occasions, three test meals which were identical apart from their MUFA and SFA contents. Expressed as a percentage of total energy the MUFA/SFA contents of the meals were: (1) 12 %/17 %; (2) 17 %/12% and (3) 24 %/5 %. The contribution of the intestinally-derived lipoproteins (chylomicrons) to the lipaemic response was investigated by determining the time to reach peak concentration and the total and incremental areas under the time response curves (AUC and incremental AUC) for RE, apoB-48 and triacylglycerol in the TRL fraction. No significant differences in these measurements were observed for the three meals. However, visual comparison of the postprandial responses to the three meals suggested that as meal MUFA content increased there was a tendency for the triacylglycerol, apoB-48 and RE responses to become biphasic as opposed to the typical monophasic response seen with the 12% MUFA/17% SFA meal. Comparison of the apoB-48 and RE responses for the three test meals confirmed other workers’ findings of delayed entry of RE relative to apoB-48 in TRL. The value of the two markers in investigating dietary fat absorption and metabolism is discussed.

Consumer robotic products: studying the factors that influence market adoption

The aim of this article is to identify the key factors that are associated with the adoption of a commercial robot in the home. This article is based on the development of the robot product Cybot by the University of Reading in conjunction with a publisher (Eaglemoss International Ltd.). The robots were distributed through a new part-work magazine series (Ultimate Real Robots) that had long-term customer usage and retention. A part-work is a serial publication that is issued periodically (e.g., every two weeks), usually in magazine format, and builds into a complete collection. This magazine focused on robotics and was accompanied by cover-mounted component parts that could be assembled, with instructions, by the user to build a working robot over the series. In total, the product contributed over half a million operational domestic robots to the world market, selling over 20 million robot part-work magazines across 18 countries, thereby providing a unique breadth of insight. Gaining a better understanding of the overall attitudes that customers of this product had toward robots in the home, their perception of what such devices could deliver and how they would wish to interact with them should provide results applicable to the domestic appliance, assistance/care, entertainment, and educational markets.

Slow-release RGD-peptide hydrogel monoliths

We report on the formation of hydrogel monoliths formed by functionalized peptide Fmoc-RGD (Fmoc: fluorenylmethoxycarbonyl) containing the RGD cell adhesion tripeptide motif. The monolith is stable in water for nearly 40 days. The gel monoliths present a rigid porous structure consisting of a network of peptide fibers. The RGD-decorated peptide fibers have a β-sheet secondary structure. We prove that Fmoc-RGD monoliths can be used to release and encapsulate material, including model hydrophilic dyes and drug compounds. We provide the first insight into the correlation between the absorption and release kinetics of this new material and show that both processes take place over similar time scales.