992 resultados para 760 Grafica


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Lack of sulphur nutrition during potato cultivation has been shown to have profound effects on tuber composition, affecting in particular the concentrations of free asparagine, other amino acids and sugars. This is important because free asparagine and sugars react at high temperatures to form acrylamide, a suspect carcinogen. Free amino acids and sugars also form a variety of other compounds associated with colour and flavour. In this study the volatile aroma compounds formed in potato flour heated at 180 °C for 20 min were compared for three varieties of potato grown, with and without sulphur fertiliser. Approximately 50 compounds were quantified in the headspace extracts of the heated flour, of which over 40 were affected by sulphur fertilisation and/or variety. Many of the 41 compounds found at higher concentrations in the sulphur-deficient flour were Strecker aldehydes and compounds formed from their condensation, whereas only one compound, benzaldehyde, behaved in the same way as did acrylamide and was found at higher concentrations in the sulphur-sufficient flour. The reasons for these effects are discussed.

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The relative rate method has been used to measure the room-temperature rate constants for the gasphase reactions of ozone and NO3 with selected monoterpenes and cyclo-alkenes with structural similarities to monoterpenes. Measurements were carried out at 298 ! 2 K and 760 ! 10 Torr. The following rate constants (in units of 10"18 cm3 molecule"1 s"1) were obtained for the reaction with ozone: methyl cyclohexene (132 ! 17), terpinolene (1290 ! 360), ethylidene cyclohexane (223 ! 57), norbornene (860 ! 240), t-butyl isopropylidene cyclohexane (1500 ! 460), cyclopentene (543 ! 94), cyclohexene (81 ! 18), cyclooctene (451 ! 66), dicyclopentadiene (1460 ! 170) and a-pinene (107 ! 13). For the reaction with NO3 the rate constants obtained (in units of 10"12 cm3 molecule"1 s"1) were: methyl cyclohexene (7.92 ! 0.95), terpinolene (47.9 ! 4.0), ethylidene cyclohexane (4.30 ! 0.24), norbornene (0.266 ! 0.029), cyclohexene (0.540 ! 0.017), cyclooctene (0.513 ! 0.029), dicyclopentadiene (1.20 ! 0.10) and a-pinene (5.17 ! 0.62). Errors are quoted as the root mean square of the statistical error (95% con!dence) and the quoted error in the rate constant for the reference compound. Combining these results with previous studies, new recommendations for the rate constants are presented. Molecular orbital energies were calculated for each alkene and the kinetic data are discussed in terms of the deviation from the structureeactivity relationship obtained from the rate constants for a series of simple alkenes. Lifetimes with respect to key initiators of atmospheric oxidation have been calculated suggesting that the studied reactions play dominant roles in the night-time removal of these compounds from the atmosphere.

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This article examines the marginal position of artisanal miners in sub-Saharan Africa, and considers how they are incorporated into mineral sector change in the context of institutional and legal integration. Taking the case of diamond and gold mining in Tanzania, the concept of social exclusion is used to explore the consequences of marginalization on people's access to mineral resources and ability to make a living from artisanal mining. Because existing inequalities and forms of discrimination are ignored by the Tanzanian state, the institutionalization of mineral titles conceals social and power relations that perpetuate highly unequal access to resources. The article highlights the complexity of these processes, and shows that while legal integration can benefit certain wealthier categories of people, who fit into the model of an 'entrepreneurial small-scale miner', for others adverse incorporation contributes to socio-economic dependence, exploitation and insecurity. For the issue of marginality to be addressed within integration processes, the existence of local forms of organization, institutions and relationships, which underpin inequalities and discrimination, need to be recognized.

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BACKGROUND. To use spectra acquired by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) from pre- and post-digital rectal examination (DRE) urine samples to search for discriminating peaks that can adequately distinguish between benign and malignant prostate conditions, and identify the peaks’ underlying biomolecules. METHODS. Twenty-five participants with prostate cancer (PCa) and 27 participants with a variety of benign prostatic conditions as confirmed by a 10-core tissue biopsy were included. Pre- and post-DRE urine samples were prepared for MALDI MS profiling using an automated clean-up procedure. Following mass spectra collection and processing, peak mass and intensity were extracted and subjected to statistical analysis to identify peaks capable of distinguishing between benign and cancer. Logistic regression was used to combine markers to create a sensitive and specific test. RESULTS. A peak at m/z 10,760 was identified as b-microseminoprotein (b-MSMB) and found to be statistically lower in urine from PCa participants using the peak’s average areas. By combining serum prostate-specific antigen (PSA) levels with MALDI MS-measured b-MSMB levels, optimum threshold values obtained from Receiver Operator characteristics curves gave an increased sensitivity of 96% at a specificity of 26%. CONCLUSIONS. These results demonstrate that with a simple sample clean-up followed by MALDI MS profiling, significant differences of MSMB abundance were found in post-DRE urine samples. In combination with PSA serum levels, obtained from a classic clinical assay led to high classification accuracy for PCa in the studied sample set. Our results need to be validated in a larger multicenter prospective randomized clinical trial.

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Sainfoin is a non-bloating temperate forage legume with a moderate-to-high condensed tannin (CT) content. This study investigated whether the diversity of sainfoin accessions in terms of CT structures and contents could be related to rumen in vitro gas and methane (CH4) production and fermentation characteristics. The aim was to identify promising accessions for future investigations. Accessions differed (P < 0·0001) in terms of total gas and CH4 productions. Fermentation kinetics (i.e. parameters describing the shape of the gas production curve and half-time gas production) for CH4 production were influenced by accession (P ≤ 0·038), but not by PEG. Accession, PEG and time affected (P < 0·001) CH4 production, but accession and PEG interaction showed only a tendency (P = 0·08). Increase in CH4 due to PEG addition was not related to CT content. Further analysis of the relationships among multiple traits (nutritional composition, CT structure and CH4 production) using principal component analysis (PCA) based on optimally weighted variables revealed differences among accessions. The first two principal component axes, PC1 (57·6%) and PC2 (18·4%), explained 76·0% of the total variation among accessions. Loading of biplots derived from both PCAs made it possible to establish a relationship between the ratio of prodelphinidin:procyanidin (PD:PC) tannins and CH4 production in some accessions. The PD:PC ratio seems to be an important source of variation that is negatively related to CH4 production. These results suggested that sainfoin accessions collected from across the world exhibited substantial variation in terms of their effects on rumen in vitro CH4 production, revealing some promising accessions for future investigations.

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The redox properties and reactivity of [Mo(CO)2(η3-allyl)(α-diimine)(NCS)] (α-diimine = bis(2,6-dimethylphenyl)-acenaphthenequinonediimine (2,6-xylyl-BIAN) and 2,2′-bipyridine (bpy)) were studied using cyclic voltammetry and IR/UV–Vis spectroelectrochemistry. [Mo(CO)2(η3-allyl)(2,6-xylyl-BIAN)(NCS)] was shown by X-ray crystallography to have an asymmetric (B-type) conformation. The extended aromatic system of the strong π-acceptor 2,6-xylyl-BIAN ligand stabilises the primary 1e−-reduced radical anion, [Mo(CO)2(η3-allyl)(2,6-xylyl-BIAN•−)(NCS)]−, that can be reduced further to give the solvento anion [Mo(CO)2(η3-allyl)(2,6-xylyl-BIAN)(THF)]−. The initial reduction of [Mo(CO)2(η3-allyl)(bpy)(NCS)] in THF at ambient temperature results in the formation of [Mo(CO)2(η3-allyl)(bpy)]2 by reaction of the remaining parent complex with [Mo(CO)2(η3-allyl)(bpy)]− produced by dissociation of NCS− from [Mo(CO)2(η3-allyl)(bpy•−)(NCS)]−. Further reduction of the dimer [Mo(CO)2(η3-allyl)(bpy)]2 restores [Mo(CO)2(η3-allyl)(bpy)]−. In PrCN at 183 K, [Mo(CO)2(η3-allyl)(2,6-xylyl-BIAN•−)(NCS)]− converts slowly to 2e−-reduced [Mo(CO)2(η3-allyl)(2,6-xylyl-BIAN)(PrCN)]− and free NCS−. At room temperature, the reduction path in PrCN involves mainly the dimer [Mo(CO)2(η3-allyl)(bpy)]2; however, the detailed course of the reduction within the spectroelectrochemical cell is complicated and involves a mixture of several unassigned products. Finally, it has been shown that the five-coordinate anion [Mo(CO)2(η3-allyl)(bpy)]− promotes in THF reduction of CO2 to CO and formate via the formation of the intermediate [Mo(CO)2(η3-allyl)(bpy)(O2CH)] and its subsequent reduction.

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This article builds on advances in social ontology to develop a new understanding of how mainstream economic modelling affects reality. We propose a new framework for analysing and describing how models intervene in the social sphere. This framework allows us to identify and articulate three key epistemic features of models as interventions: specificity, portability and formal precision. The second part of the article uses our framework to demonstrate how specificity, portability and formal precision explain the use of moral hazard models in a variety of different policy contexts, including worker compensation schemes, bank regulation and the euro-sovereign debt crisis.

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Briefing phase interactions between clients and designers are recognized as social engagements, characterized by communicative sign use, where conceptual ideas are gradually transformed into potential design solutions. A semiotic analysis of briefing communications between client stakeholders and designers provides evidence of the significance and importance of stakeholder interpretation and understanding of design, empirical data being drawn from a qualitative study of NHS hospital construction projects in the UK. It is contended that stakeholders engage with a project through communicative signs and artefacts of design, referencing personal cognitive knowledge in acts of interpretation that may be different from those of designers and externally appointed client advisers. Such interpretations occur in addition to NHS client and design team efforts to ‘engage’ with and ‘understand’ stakeholders using a variety of methods. Social semiotic theorizations indicate how narrative strategies motivate the formulation of signs and artefacts in briefing work, the role of sign authors and sign readers being elucidated as a result. Findings are contextualized against current understandings of briefing communications and stakeholder management practices, a more socially attuned understanding of briefing countering some of the process-led improvement models that have characterized much of the post-Egan report literature. A stakeholder interpretation model is presented as one potential method to safeguard against unforeseen interpretations occurring, the model aligning with the proposal for a more measured recognition of how designs can trigger interpretations among client stakeholders.

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Sahelian summer rainfall, controlled by the West African monsoon, exhibited large-amplitude multidecadal variability during the twentieth century. Particularly important was the severe drought of the 1970s and 1980s, which had widespread impacts1–6. Research into the causes of this drought has identified anthropogenic aerosol forcing3,4,7 and changes in sea surface temperatures (SSTs; refs 1,2,6,8–11) as the most important drivers. Since the 1980s, there has been some recovery of Sahel rainfall amounts2–6,11–14, although not to the pre-drought levels of the 1940s and 1950s. Here we report on experiments with the atmospheric component of a state-of-the-art global climate model to identify the causes of this recovery. Our results suggest that the direct influence of higher levels of greenhouse gases in the atmosphere was the main cause, with an additional role for changes in anthropogenic aerosol precursor emissions. We find that recent changes in SSTs, although substantial, did not have a significant impact on the recovery. The simulated response to anthropogenic greenhouse-gas and aerosol forcing is consistent with a multivariate fingerprint of the observed recovery, raising confidence in our findings. Although robust predictions are not yet possible, our results suggest that the recent recovery in Sahel rainfall amounts is most likely to be sustained or amplified in the near term.

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Morphing fears (also called transformation obsessions) involve concerns that a person may become contaminated by and acquire undesirable characteristics of others. These symptoms are found in patients with OCD and are thought to be related to mental contamination. Given the high levels of distress and interference morphing fears can cause, a reliable and valid assessment measure is needed. This article describes the development and evaluation of the Morphing Fear Questionnaire (MFQ), a 13-item measure designed to assess for the presence and severity of morphing fears. A sample of 900 participants took part in the research. Of these, 140 reported having a current diagnosis of OCD (SR-OCD) and 760 reported never having had OCD (N-OCD; of whom 24 reported a diagnosis of an anxiety disorder and 23 reported a diagnosis of depression). Factor structure, reliability, and construct and criterion related validity were investigated. Exploratory and confirmatory factor analyses supported a one-factor structure replicable across the N-OCD and SR-OCD group. The MFQ was found to have high internal consistency and good temporal stability, and showed significantly greater associations with convergent measures (assessing obsessive-compulsive symptoms, mental contamination, thought-action fusion and magical thinking) than with divergent measures (assessing depression and anxiety). Moreover, the MFQ successfully discriminated between the SR-OCD sample and the N-OCD group, anxiety disorder sample, and depression sample. These findings suggest that the MFQ has sound psychometric properties and that it can be used to assess morphing fear. Clinical implications are discussed.

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Modified fluorcanasite glasses were fabricated by either altering the molar ratios of Na(2)O and CaO or by adding P(2)O(5) to the parent stoichiometric glass compositions. Glasses were converted to glass-ceramics by a controlled two-stage heat treatment process. Rods (2 mm x 4 mm) were produced using the conventional lost-wax casting technique. Osteoconductive 45S5 bioglass was used as a reference material. Biocompatibility and osteoconductivity were investigated by implantation into healing defects (2 mm) in the midshaft of rabbit femora. Tissue response was investigated using conventional histology and scanning electron microscopy. Histological and histomorphometric evaluation of specimens after 12 weeks implantation showed significantly more bone contact with the surface of 45S5 bioglass implants when compared with other test materials. When the bone contact for each material was compared between experimental time points, the Glass-Ceramic 2 (CaO rich) group showed significant difference (p = 0.027) at 4 weeks, but no direct contact at 12 weeks. Histology and backscattered electron photomicrographs showed that modified fluorcanasite glass-ceramic implants had greater osteoconductivity than the parent stoichiometric composition. Of the new materials, fluorcanasite glass-ceramic implants modified by the addition of P(2)O(5) showed the greatest stimulation of new mineralized bone tissue formation adjacent to the implants after 4 and 12 weeks implantation. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 94A: 760-768, 2010

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The study is based on 141 pregnant Bos indicus cows, from days 20 to 70 post-insemination. First, special attention was given to the macroscopically observable phenomena of attachment of the conceptus to the uterus, i.e. the implantation, from about days 20 to 30 post-insemination up to day 70, and placentome development by growth, vascularization and increase in the number of cotyledons opposite to the endometrial caruncles. Secondly, as for the conceptuses, semiquantitative, statistical analyses were performed of the lengths of chorio-allantois, amnion and yolk sac; and the different parts of the centre and two extremes of the yolk sacs were also analysed. Thirdly, the embryos/foetuses corresponding to their membranes were measured by their greatest length and by weight, and described by the appearance of external developmental phenomena during the investigated period like neurulation, somites, branchial arcs, brain vesicles, limb buds, C-form, pigmented eye and facial grooves. In conclusion, all the data collected in this study from days 20 to 70 of bovine pregnancy were compared extensively with corresponding data of the literature. This resulted in an `embryo/foetal age-scale`, which has extended the data in the literature by covering the first 8 to 70 days of pregnancy. This age-scale of early bovine intrauterine development provides model for studies, even when using slaughtered cows without distinct knowledge of insemination or fertilization time, through macroscopic techniques. This distinctly facilitates research into the cow, which is now being widely used as `an experimental animal` for testing new techniques of reproduction like in vitro fertilization, embryo transfer and cloning.

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A detailed climatology of the cyclogenesis over the Southern Atlantic Ocean (SAO) from 1990 to 1999 and how it is simulated by the RegCM3 (Regional Climate Model) is presented here. The simulation used as initial and boundary conditions the National Centers for Environmental Prediction-Department of Energy (NCEP/DOE) reanalysis. The cyclones were identified with an automatic scheme that searches for cyclonic relative vorticity (zeta(10)) obtained from a 10-m height wind field. All the systems with zeta(10) a parts per thousand currency sign -1.5 x 10(-5) s(-1) and lifetime equal or larger than 24 h were considered in the climatology. Over SAO, in 10 years were detected 2,760 and 2,787 cyclogeneses in the simulation and NCEP, respectively, with an annual mean of 276.0 +/- A 11.2 and 278.7 +/- A 11.1. This result suggests that the RegCM3 has a good skill to simulate the cyclogenesis climatology. However, the larger model underestimations (-9.8%) are found for the initially stronger systems (zeta(10) a parts per thousand currency sign -2.5 x 10(-5) s(-1)). It was noted that over the SAO the annual cycle of the cyclogenesis depends of its initial intensity. Considering the systems initiate with zeta(10) a parts per thousand currency sign -1.5 x 10(-5) s(-1), the annual cycle is not well defined and the higher frequency occurs in the autumn (summer) in the NCEP (RegCM3). The stronger systems (zeta(10) a parts per thousand currency sign -2.5 x 10(-5) s(-1)) have a well-characterized high frequency of cyclogenesis during the winter in both NCEP and RegCM3. This work confirms the existence of three cyclogenetic regions in the west sector of the SAO, near the South America east coast and shows that RegCM3 is able to reproduce the main features of these cyclogenetic areas.