La gestion des stocks est un élément très important pour les entreprises. Il faut pouvoir satisfaire les clients à moindre coût. Pour cela, il est nécessaire d'être en possession de tous es composants, pour fabriquer les produits demandés et les livrer à la date voulue. En effet, une mauvaise politique d'approvisionnement en composants conduit soit à des retards de livraison, qui engendrent des frais, soit à des stocks inutiles. Dans cette thèse, nous étudions la planification des réapprovisionnements en composants pour les systèmes de production de différentes structures. Nous travaillons avec les nomenclatures à plusieurs niveaux et nous tenons compte des aléas des délais d'approvisionnement. Nous avons choisi comme variables de décision celles qui correspondaient aux paramètres de la méthode MRP, comme le temps de cycle planifié. L'objectif pratique de notre étude étant également de fournir des techniques pour le paramétrage des logiciels MRP en présence de ce type d'aléas. Nous avons proposé des modèles et avons démontré leurs propriétés théoriques intéressantes ainsi que des approches d'optimisation nouvelles pour ce type de problème.

The main objectives of this research were to examine effects of protein modification (protein cleavage and crosslinking) on turkey meat gelation and to evaluate textural properties and water holding capacity of meat gels prepared from normal and PSE (pale, soft, exudative) turkey breast meat.<p>First, the effect of protein degradation on turkey breast meat gelation was studied. To create different extent of proteolysis in the meat, á-chymotrypsin (EC 3.4.21.1) was added to normal and PSE meat batters at 0, 2.5, 5 and 10 ppm levels. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cooked meat gels showed progressive protein hydrolysis with increasing enzyme level. Texture profile analysis and torsional analysis of the cooked meat gels showed an incremental deterioration in texture with increasing enzyme level. This inferior texture caused by proteolysis was similar to that observed in the gels made from PSE turkey meat alone. Pearson correlation coefficients indicated gel textural properties and expressible moisture were highly correlated to the degree of proteolysis, especially to that of myosin heavy chain (p < 0.001).<p>The second study focused on modifying protein size to improve meat gelation, especially PSE meat gelation. Transglutaminase (TGase, EC 2.3.2.13) was chosen due to its ability to catalyze crosslinking of proteins. Pea protein isolate, an alternative to soy protein, was also evaluated as a meat protein extender. Textural profile and torsional gelometry analyses of the cooked meat gels showed TGase alone significantly (p < 0.05) increased gel texture, especially for those made from PSE meat. However, cook yield of the meat gels was compromised possibly due to steric effects. Addition of pea protein isolate alone improved cook yield and gel texture, especially for the gels made from PSE meat. The combination of TGase and pea protein produced the strongest meat gels, while maintaining a similar cook yield to the control. SDS-PAGE showed the disappearance of several protein bands contributed from the meat or pea protein with TGase addition, indicating that these likely were crosslinked and too large to enter the gel. Dynamic rheological analysis revealed TGase altered the viscoelastic properties of the meat or meat-pea protein mixtures and produced more elastic gels on cooling.<p>This research indicated proteolysis had a dramatic impact on textural properties of turkey breast meat gels. Crosslinking of proteins catalyzed by TGase significantly improved gel texture, especially for the gels made from PSE meat. However, TGase-assisted crosslinking of proteins resulted in greater cooking losses unless an extender/adjunct such as pea protein was added.

The main objectives of this research were to examine effects of protein modification (protein cleavage and crosslinking) on turkey meat gelation and to evaluate textural properties and water holding capacity of meat gels prepared from normal and PSE (pale, soft, exudative) turkey breast meat.<p>First, the effect of protein degradation on turkey breast meat gelation was studied. To create different extent of proteolysis in the meat, á-chymotrypsin (EC 3.4.21.1) was added to normal and PSE meat batters at 0, 2.5, 5 and 10 ppm levels. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cooked meat gels showed progressive protein hydrolysis with increasing enzyme level. Texture profile analysis and torsional analysis of the cooked meat gels showed an incremental deterioration in texture with increasing enzyme level. This inferior texture caused by proteolysis was similar to that observed in the gels made from PSE turkey meat alone. Pearson correlation coefficients indicated gel textural properties and expressible moisture were highly correlated to the degree of proteolysis, especially to that of myosin heavy chain (p < 0.001).<p>The second study focused on modifying protein size to improve meat gelation, especially PSE meat gelation. Transglutaminase (TGase, EC 2.3.2.13) was chosen due to its ability to catalyze crosslinking of proteins. Pea protein isolate, an alternative to soy protein, was also evaluated as a meat protein extender. Textural profile and torsional gelometry analyses of the cooked meat gels showed TGase alone significantly (p < 0.05) increased gel texture, especially for those made from PSE meat. However, cook yield of the meat gels was compromised possibly due to steric effects. Addition of pea protein isolate alone improved cook yield and gel texture, especially for the gels made from PSE meat. The combination of TGase and pea protein produced the strongest meat gels, while maintaining a similar cook yield to the control. SDS-PAGE showed the disappearance of several protein bands contributed from the meat or pea protein with TGase addition, indicating that these likely were crosslinked and too large to enter the gel. Dynamic rheological analysis revealed TGase altered the viscoelastic properties of the meat or meat-pea protein mixtures and produced more elastic gels on cooling.<p>This research indicated proteolysis had a dramatic impact on textural properties of turkey breast meat gels. Crosslinking of proteins catalyzed by TGase significantly improved gel texture, especially for the gels made from PSE meat. However, TGase-assisted crosslinking of proteins resulted in greater cooking losses unless an extender/adjunct such as pea protein was added.

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Turkey with pale, soft, exudative (PSE)-like condition is one of the growing concerns in the poultry industry as it affects meat quality due to low ultimate pH at 24 h post mortem (pH24). Hence, there is a need for better utilization of PSE-like meat for the preparation of further processed products. In the first two studies, the biochemical, functional, rheological, and textural properties of proteins in turkey breast meat with different pH24 in fresh and frozen conditions were investigated. These studies revealed that low and normal pH meat had similar properties indicating similar extent of protein denaturation, except for lower water holding capacity (WHC) in low pH meat. High pH meat had similar or better functional properties than normal pH meat. In the third study, improvements in WHC, protein solubility, and gel forming ability of low pH meat was achieved by the application of high pressure processing (HPP). / Food Science and Technology

Submitted by Cibele Nogueira (cibelenogueira@ufgd.edu.br) on 2016-04-28T18:29:46Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) SILVANIZAMACHADO.pdf: 856398 bytes, checksum: 24b40d3291de46504cb667751caf6435 (MD5) / Made available in DSpace on 2016-04-28T18:29:46Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) SILVANIZAMACHADO.pdf: 856398 bytes, checksum: 24b40d3291de46504cb667751caf6435 (MD5) Previous issue date: 2013-08-21 / The aim of this study was to investigate the effect of pre-slaughter handling and transport management on the occurrence of PSE (Pale, Soft and Exudative) meat based on a database of pigs slaughtered in a commercial slaughterhouse located in the region of greater Dourados, MS, Brazil. For that purpose, two evaluation strategies were adopted. The first refers to the application of Integrated Multivariate Analysis in 1,832 carcasses, and the second to the application of Logistic Regression in 854 selected carcasses. For the first study, nine variables were considered which may affect pork quality and, of these, seven are related to pre-slaughter handling. The purpose was to identify which ones of the variables evaluated were the most relevant for the qualitative carcass study. Thus, by means of the Principal Component Analysis, it was seen that the first five components explained 89.28% of total variance. The second study had the purpose of certifying the effect of transportation and environment on the probable risk of occurrence of PSE meat. Therefore, eight variables were considered, adopting pH45 as the dependent variable and the others as explanatory variables: carcass temperature, environment, time of shipment, trip conditions, distance between the farm and the slaughterhouse, average speed during transportation and resting time in the slaughterhouse stalls. Thus, a logistic regression model was prepared in which the dependent variable was constructed by identification of PSE meat in swine carcasses with pH45 values less than or equal to 5.8. The maximum likelihood method for estimation of the parameters and the stepwise technique for selection of explanatory variables were applied to obtain the model with the greatest predictive capability. The model obtained presented predictive ability of 91.8%. / Este trabalho teve como objetivo investigar a influência do manejo pré-abate e das operações de transporte na incidência de carne PSE (Pale, Soft and Exudative), a partir de um banco de dados de suínos abatidos em um frigorifico comercial, localizado na região da grande Dourados-MS. Para tanto, adotou-se duas estratégias de avaliação, a primeira refere-se à aplicação de Análise Multivariada Integrada, em 1.832 carcaças e a segunda à aplicação de Regressão Logística Múltipla em 854 carcaças selecionadas. Para o primeiro estudo foram consideradas nove variáveis que podem influenciar a qualidade da carne suína, sendo que destas, sete estão relacionadas ao manejo pré-abate. A finalidade foi identificar quais das variáveis avaliadas eram mais relevantes para o estudo qualitativo da carcaça. Dessa forma, por meio da Análise de Componentes Principais, observou-se que as cinco primeiras componentes explicaram 89,28% da variância total. O segundo estudo, teve a finalidade de constatar a influência do transporte e da ambiência na probabilidade de risco de incidência de carne PSE, para tanto considerou-se oito variáveis, adotando o pH45 como variável dependente e as demais como variáveis explicativas: temperatura de carcaça, ambiência, tempo de embarque, viagem, distância entre a granja e o abatedouro, velocidade média durante o transporte e tempo de descanso nas baias do frigorífico. Assim, foi elaborado um modelo de regressão logística múltipla, em que a variável dependente foi construída pela identificação de carne PSE em carcaças de suínos com valores de pH45 inferior ou igual a 5,8. Para obtenção do modelo com maior capacidade de predição, aplicou-se o método de máxima verossimilhança para estimação de parâmetros e a técnica stepwise para seleção de variáveis explicativas. O modelo obtido apresentou capacidade de predição de 91,8%.

Self-efficacy was found as a strong predictor of sport performance in many researches. In this paper we focus on self-efficacy in children doing sport and we observe the relationship between self-efficacy, competitive anxiety and sport performance in children. In theoretical part we define self-efficacy, its sources and types of self-efficacy measurements in sport and physical activity. We summarize knowledge from previous researches and we also give some information about sport in children, especially about their physical and mental sport preparation. Empirical part of this paper presents our research done with young swimmers aged 10-15 years. We used Physical Self-efficacy Scale for children PSE and Competitive State Anxiety Inventory for Children CSAI-2C. Despite of our assumptions we didn't find self-efficacy or competitive anxiety to be a strong predictor of objective sport performance. Significance was found in subjective performance and its relationship to self-efficacy (positive correlations) and precompetitive cognitive anxiety (negative correlations). Keywords: Self-efficacy, precompetitive anxiety, sport, adolescence, CSAI-2C, PSE

The thesis is focused on state interventions and regulation on field of stock exchanges. On special examples I show for and against argumentation of real precautions. I repeal the questions of public konvenience of these precautions. In the first part of the thesis I begin with historical genesis of exchange especially in our area including the origin -- private or state. The first part continue with theoretical functions of stock exchange and its fulfilment in case of The Stock Exchange in Prague. In the second part I present dilemma of squeeze-out or expropriation of minority shareholders.There will be arguments of proposers, opponents and also neutral arbiter representing by The Constitutional Court of the Czech Republic. In the third part of the thesis I present an example of foreign regulation. It is Sarbanes-Oxley Act with its impact on different entities. In conclusion I propose some changes and I want to give a support to discussion about state admission to regulation of stock markets.

Amount of rutin and quercetin in bark and leaves from different type of Sambucus nigra was determined in this diploma thesis. Records of amounts were compared with amounts in significant sources of these flavonoids. Matters from raw matrix were obtained with pressurized solvent extraction (PSE) and pressurized hot water extraction (PHWE). There was use temperature 120°C, pressure 150 bar, three times 5-min cycles for PSE. There were used 80°C, 150 bar, three 5-min cycles for rutin extracted with PHWE and the same condition were used for extraction of quercetin only the temperature was changed to 100 °C. Analysis of rutin and quercetin were carry out high performance liquid chromatography (HPLC) with diode array detection (DAD), where was used SUPELCOSILTM LC 8DB column (5µm; 250 x 4.6 mm). Methanol: water: formic acid (36: 61.5: 2.5, pH 2.17 2.28) was used like a mobile phase. The flow of the mobile phase was set up 0.7 ml/min. Size of sample was 10 µl. The most amount of rutin was determined in the leaves of wild kind of Sambucus nigra with methanol extraction and hot water too. Extraction with PHWE was more effectively. There were determined 5.58 mg of rutin in one gram of sample from wild Sambucus nigra. There were determined the smallest amount of rutin in Sambucus nigra Körsör. There was found only 0.13 mg/g with extraction PHWE. The quercetin wasn’t determined in any Sambucus nigra leaves. There were found both of the flavonoids (rutin and quercetin) in the branch of Sambucus nigra. The rutin was determined in the small amount in wild kind but it was found in the important amount in Sambucus nigra cultivar. Whereas the quercetin was found in higher concentration than rutin when was finding the ideal conditions for extraction of branch. The quercetin was chosen like more important in light of amount. In the end the quercetin wasn’t detected in any Sambucus nigra cultivars. The most amount of quercetin was determined in wild sambucus nigra, 0.24 mg/g. The most amount of rutin was found in Sambucus nigra Albida, 2.33 mg/g.