955 resultados para Problem solving Study and teaching


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Using theoretical applications, the authors present an overview of theories that highlight approaches for teaching culturally sensitive content, personal experiences as educator and colleague in a predominantly white college campus and strategies for addressing culturally insensitive experiences in and outside the classroom. Presenters focus on the recruitment and retention of people of color and stress the need for today's predominantly white institutions to become more knowledgeable, tolerant and sensitive about their environments in an effort to make them more accepting.

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The objective of this study was to identify the socioeconomic and demographic characteristics of children and adolescents who study and work outside their home. This non-experimental, correlational, cross-sectional study was performed using questionnaires applied to primary education students, enrolled in public schools in Ribeirao Preto (Brazil). Two schools were selected through a draw. Data analysis was performed using Statistical Package for Social Sciences, version 14.0. Of the 133 students who answered the questionnaire, 36 (27.7%) reported working outside their home, 20.6% were between 11 and 13 years of age, and 66.7% were male (p=0.000) and had started working early to help with the family income (p=0.003). The salary they received helped comprise the family income, and it was found that as the family income increased, the need for the youngsters to work was reduced. It was found that many factors contribute to these subjects' early start at work, including family size, structure and poverty.

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A method for the simultaneous quantification of lycopene, beta-carotene, retinol and alpha-tocopherol by high-performance liquid chromatography (HPLC) with Vis/fluorescence detection with isocratic elution was optimized and validated. The method consists of a rapid and simple liquid-liquid extraction procedure and a posterior quantification of extracted supernatants by HPLC. Aliquots of plasma were stored at -20 degrees C for three months for stability study. The methodology was applied to samples from painters and individuals not exposed to paints (n = 75). The assay was linear for all vitamins (r > 0.99). Intra-and inter-run precisions were obtained with coefficient of variation smaller than 5%. The accuracies ranged from 0.29 to -5.80% and recoveries between 92.73 and 101.97%. Plasma samples and extracted supernatants were stable for 60 days at -20 degrees C. A significant decrease of lycopene, beta-carotene and retinol concentrations in plasma from exposed individuals compared to non-exposed individuals (p < 0.05) was observed. The method is simple, reproducible, precise, accurate and sensitive, and can be routinely utilized in clinical laboratories.

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Defining pharmacokinetic parameters and depletion intervals for antimicrobials used in fish represents important guidelines for future regulation by Brazilian agencies of the use of these substances in fish farming. This article presents a depletion study for oxytetracycline (OTC) in tilapias (Orechromis niloticus) farmed under tropical conditions during the winter season. High performance liquid chromatography, with fluorescence detection for the quantitation of OTC in tilapia fillets and medicated feed, was developed and validated. The depletion study with fish was carried out under monitored environmental conditions. OTC was administered in the feed for five consecutive days at daily dosages of 80 mg/kg body weight. Groups of ten fish were slaughtered at 1, 2, 3, 4, 5, 8, 10, 15, 20, and 25 days after medication. After the 8th day posttreatment, OTC concentrations in the tilapia fillets were below the limit of quantitation (13 ng/g) of the method. Linear regression of the mathematical model of data analysis presented a coefficient of 0.9962. The elimination half- life for OTC in tilapia fillet and the withdrawal period were 1.65 and 6 days, respectively, considering a percentile of 99% with 95% of confidence and a maximum residue limit of 100 ng/g. Even though the study was carried out in the winter under practical conditions where water temperature varied, the results obtained are similar to others from studies conducted under controlled temperature.

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Some properties of canna (Canna indica L.) and bore (Alocasia macrorrhiza) starches were evaluated and compared using cassava starch (Manihot esculenta Crantz) as a reference. Proximate analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and viscosity measurements were performed. Canna and bore starches showed a similar degree of purity as that of the cassava starch. Canna starch exhibited higher thermal stability and viscosity of solution values than those of bore and cassava starches. XRD spectra showed that canna starch crystallizes as a B-type structure; however, bore and cassava starches crystallize as an A-type structure. Results proved that canna and bore starches are promising bio(materials), obtained from unconventional sources, to be used for industrial applications, as their physicochemical properties are similar to those of cassava starch, which it is known has potential applications in this area.

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A method for the simultaneous quantification of lycopene, β-carotene, retinol and α-tocopherol by high-performance liquid chromatography (HPLC) with Vis/fluorescence detection with isocratic elution was optimized and validated. The method consists of a rapid and simple liquid-liquid extraction procedure and a posterior quantification of extracted supernatants by HPLC. Aliquots of plasma were stored at -20°C for three months for stability study. The methodology was applied to samples from painters and individuals not exposed to paints (n = 75). The assay was linear for all vitamins (r > 0.99). Intra- and inter-run precisions were obtained with coefficient of variation smaller than 5%. The accuracies ranged from 0.29 to -5.80% and recoveries between 92.73 and 101.97%. Plasma samples and extracted supernatants were stable for 60 days at -20°C. A significant decrease of lycopene, β-carotene and retinol concentrations in plasma from exposed individuals compared to non-exposed individuals (p < 0.05) was observed. The method is simple, reproducible, precise, accurate and sensitive, and can be routinely utilized in clinical laboratories.

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Management and organization literature has extensively noticed the crucial role that improvisation assumes in organizations, both as a learning process (Miner, Bassoff & Moorman, 2001), a creative process (Fisher & Amabile, 2008), a capability (Vera & Crossan, 2005), and a personal disposition (Hmielesky & Corbett, 2006; 2008). My dissertation aims to contribute to the existing literature on improvisation, addressing two general research questions: 1) How does improvisation unfold at an individual level? 2) What are the potential antecedents and consequences of individual proclivity to improvise? This dissertation is based on a mixed methodology that allowed me to deal with these two general research questions and enabled a constant interaction between the theoretical framework and the empirical results. The selected empirical field is haute cuisine and the respondents are the executive chefs of the restaurants awarded by Michelin Guide in 2010 in Italy. The qualitative section of the dissertation is based on the analysis of 26 inductive case studies and offers a multifaceted contribution. First, I describe how improvisation works both as a learning and creative process. Second, I introduce a new categorization of individual improvisational scenarios (demanded creative improvisation, problem solving improvisation, and pure creative improvisation). Third, I describe the differences between improvisation and other creative processes detected in the field (experimentation, brainstorming, trial and error through analytical procedure, trial and error, and imagination). The quantitative inquiry is founded on a Structural Equation Model, which allowed me to test simultaneously the relationships between proclivity to improvise and its antecedents and consequences. In particular, using a newly developed scale to measure individual proclivity to improvise, I test the positive influence of industry experience, self-efficacy, and age on proclivity to improvise and the negative impact of proclivity to improvise on outcome deviation. Theoretical contributions and practical implications of the results are discussed.

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Analytical pyrolysis was used to investigate the formation of diketopiperazines (DKPs) which are cyclic dipeptides formed from the thermal degradation of proteins. A quali/quantitative procedure was developed combining microscale flash pyrolysis at 500 °C with gas chromatography-mass spectrometry (GC-MS) of DKPs trapped onto an adsorbent phase. Polar DKPs were silylated prior to GC-MS. Particular attention was paid to the identification of proline (Pro) containing DKPs due to their greater facility of formation. The GC-MS characteristics of more than 80 original and silylated DKPs were collected from the pyrolysis of sixteen linear dipeptides and four model proteins (e.g. bovine serum albumin, BSA). The structure of a novel DKP, cyclo(pyroglutamic-Pro) was established by NMR and ESI-MS analysis, while the structures of other novel DKPs remained tentative. DKPs resulted rather specific markers of amino acid sequence in proteins, even though the thermal degradation of DKPs should be taken into account. Structural information of DKPs gathered from the pyrolysis of model compounds was employed to the identification of these compounds in the pyrolysate of proteinaceous samples, including intrinsecally unfolded protein (IUP). Analysis of the liquid fraction (bio-oil) obtained from the pyrolysis of microalgae Nannochloropsis gaditana, Scenedesmus spp with a bench scale reactor showed that DKPs constituted an important pool of nitrogen-containing compounds. Conversely, the level of DKPs was rather low in the bio-oil of Botryococcus braunii. The developed micropyrolysis procedure was applied in combination with thermogravimetry (TGA) and infrared spectroscopy (FT-IR) to investigate surface interaction between BSA and synthetic chrysotile. The results showed that the thermal behavior of BSA (e.g. DKPs formation) was affected by the different form of doped synthetic chrysotile. The typical DKPs evolved from collagen were quantified in the pyrolysates of archaeological bones from Vicenne Necropolis in order to evaluate their conservation status in combination with TGA, FTIR and XRD analysis.

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Dystrophin is a subsarcolemmal protein critical for the integrity of muscle fibers by linking the actin cytoskeleton to the extracellular matrix via the dystroglycan complex. It is reported that dystroglycans are also localized in the skin, at dermal-epidermal junction. Here we show that epidermal melanocytes express dystrophin at the interface with the basement membrane. The full-length muscle isoform mDp427 was clearly detectable in epidermis and in melanocyte cultures as assessed by RNA and western blot analysis. Dystrophin was absent in Duchenne Muscular Dystrophy (DMD) patients melanocytes, and the ultrastructural analysis revealed mitochondrial alterations, similar to those occurring in myoblasts from the same patients. Interestingly, mitochondrial dysfunction of DMD melanocytes reflected the alterations identified in dystrophin-deficient muscle cells. In fact, mitochondria of melanocytes from DMD patients accumulated tetramethylrhodamine methyl ester but, on the contrary of control donor, mitochondria of DMD patients readily depolarized upon the addition of oligomycin, suggesting either that they are maintaining the membrane potential at the expense of glycolytic ATP, or that they are affected by a latent dysfunction unmasked by inhibition of the ATP synthase. Melanocyte cultures can be easily obtained by conventional skin biopsies, less invasive procedure than muscular biopsy, so that they may represent an alternative cellular model to myoblast for studying and monitoring dystrophinopathies also in response to pharmacological treatments.