Introdução: Os exames de Raios-X são utlizados para avaliação das curvaturas da coluna vertebral, porém, esses exames podem ser contra indicados em muitos casos, dessa forma a utilização da avaliação não invasiva é incentivada. Essa avaliação é baseada na palpação dos processos espinhosos que estão na superfície da pele, para isso, deve-se verificar se os resultados angulares oriundos dos processos espinhosos podem ser utilizados como forma de avaliação válida e reprodutível. Objetivos: (1) revisar na literatura os métodos invasivos de avaliação da coluna vertebral sagital; (2) desenvolver uma metodologia alternativa de medição das curvaturas sagitais da coluna vertebral, a partir dos processos espinhosos, baseada no cálculo da flecha sagital (f) e no ângulo (AF) das curvaturas originário da f; (3) verificar se essa metodologia é capaz de fornecer informações acuradas e precisas das curvaturas da coluna vertebral de crianças, a partir da avaliação da validade concorrente em relação ao padrão ouro, reprodutibilidade intra e interavaliador, sensibilidade e especificidade; e (4) identificar os limites de normalidade das curvaturas para a f e para o AF. Metodologia: Estudo 1 - A revisão sistemática da literatura foi realizada nas bases: Scopus, Science, Bireme e Pubmed. As palavras-chave utilizadas foram: "Validation Studies" OR “Reproducibility of Results” AND "Thoracic Vertebrae" OR "Lumbar Vertebrae" AND "Radiography”. Os principais desfechos extraídos foram os métodos utilizados para avaliar as curvaturas torácica e lombar da coluna vertebral no plano sagital através de exames de Raios-X. Estudo 2 - Para o estudo de validação, a amostra foi composta por exames de Raios-X da coluna vertebral de crianças, pertencentes a um banco de dados. Foram avaliadas, no plano sagital, as curvaturas torácica (n=90) e lombar (n=89). A análise estatística foi realizada no software SPSS versão 18.0, sendo o nível de significância de 0,05. Para a validade concorrente entre o AF e o AC foram utilizados: Teste de Correlação Produto-Momento de Pearson, Teste t independente, cálculo do erro RMS, Teste de Correlação de Morgan-Pitman e análise gráfica de Bland e Altman. Para a reprodutibilidade intra-avaliador das duas medidas do Av1 (1º dia x 2º dia) e para a reprodutibilidade interavaliador das medidas dos três avaliadores (Av1 x Av2 x Av3) foi utilizado o ICC, MAD, SEM e MDC. Resultados: Estudo 1 - Dos 1383 artigos previamente localizados, 22 artigos foram selecionados, em que, somente 2 apresentaram fraca evidência científica. Foram encontrados nove métodos diferentes. Com relação à reprodutibilidade dos métodos, os estudos mostraram resultados que variaram de moderada a excelente reprodutibilidade. Os artigos de validade mostraram grande correlação do método proposto com o padrão ouro; Estudo 2 - Tanto na região torácica (r= -0,763 com p<0,001), quanto na lombar (r= -0,686 com p<0,001), houve grande e significativa correlação entre o AF ajustado e o AC, o teste t de student não demonstrou diferença significativa entre os dois métodos, o baixo erro RMS determinou boa acurácia do método proposto, e a variância foi significativa na torácica, porém esse resultado não foi verificado na região lombar. A diferença média entre o AC e o AF ajustado (AC-AF) foi de 0°, tanto para a torácica e quanto para a lombar, e o desvio-padrão da média das diferenças na torácica foi de +12,4° e na lombar de +13,9°. AF ajustado e f apresentam boa especificidade e sensibilidade, porém alguns indivíduos foram classificados como falsos negativos na região torácica e alguns falsos positivos na região lombar. Os valores de ICC do AF ajustado foram semelhantes ou melhores do que os valores de ICC do padrão ouro, tanto intra quanto interavaliadores. Ainda, os valores de MAD, SEM e MDC do AF ajustado foram sempre menores do que os do AC,seja na coluna torácica ou na lombar. Os limites de normalidade na região torácica foram: de 0,97 cm à 3,83 cm para f e de 20° à 50° para o AF ajustado. Os limites de normalidade na região lombar foram: de 0,37cm à 3,81cm para a f e de 23,06° à 53,60° para o AF ajustado. Conclusão: O AF ajustado e f são válidos e reprodutíveis para avaliação da cifose torácica e da lordose lombar de crianças, apresentando fortes valores de correlação com o padrão ouro, bem como bons e excelentes valores de reprodutibilidade associados a baixos erros e variabilidade das medidas, indicando ser uma ferramenta precisa e confiável na avaliação da coluna vertebral. / Introduction: The X-ray examinations are utlizados to evaluate spinal curvatures, however, these tests may be contraindicated in many cases, so that the use of noninvasive evaluation is encouraged. This assessment is based on palpation of the spinous processes that are on the skin surface, for this we must verify that the angular results coming from the spinous processes can be used as an assessment tool valid and reproducible.Objectives: (1) review the literature about invasive methods for assessing sagittal spinal column; (2) developing an alternative method of measurement of the sagittal curvature of the spine, from the spinous processes, based on calculation of the sagittal fleche (f) and angle (AF) originating from the curvatures f; (3) verify that the methodology is able to provide accurate and precise information of the curvatures of the spine in children, based on the assessment of concurrent validity with respect to the gold standard, intra- and inter reliability, sensitivity and specificity; and (4) identify the boundaries of normality for f and AF. Methodology: Study 1 - A systematic literature review was performed on databases: Scopus, Science, Bireme and Pubmed. The key words used were: "Validation Studies" OR "Reproducibility of Results" AND "Thoracic Vertebrae" OR "Lumbar Vertebrae" AND "Radiography" The main outcome measures were extracted from the methods used to assess the thoracic and lumbar curvatures of the spine. in the sagittal plane by X-Rays Study 2 - For the validation study, the sample consisted of X-Ray of the spine of children belonging to a database. Toe thoracic curvature (n = 90) and lumbar (n = 89) Statistical analysis was performed using SPSS software version 18.0, and the 0.05 significance level to the concurrent validity between the AF and the AC were used.: Correlation Test Product-Moment Pearson, independent t test, RMS error of calculation, Morgan-Pitman's correlation test and graphical analysis of Bland and Altman. For intra-rater reproducibility of the two Av1 measures (Day 1 x 2nd day ) and for inter-rater reproducibility of the measurements of the three evaluators (Av1 x x Av2 AV3) was used intraclass correlation coefficient (ICC), and the MAD calculation, SEM and MDC. Results: Study 1 - Of the 1383 articles previously located, 22 articles were selected, in which only two showed weak scientific evidence. They found nine different methods. Regarding the reproducibility of the methods, the studies showed results which ranged from moderate to excellent reproducibility. The validity of articles showed high correlation of the proposed method with the gold standard; Study 2 - Both in the thoracic region (r = -0.763 p <0.001) and lumbar (r =-0.686 p <0.001), there was a great and significant correlation between AF and set the AC, the Student t test did not show significant difference between the two methods, low RMS error determined good accuracy of the proposed method, and the variance was significant in the chest, but this effect was not detected in the lumbari region. The average difference between the AC and the set AF (AF-AC) was 0°, both the thoracic and the lumbar for, and the average standard deviation of the differences in the thoracic was +12,4° and lumbar from +13,9°. AF set have good specificity and sensitivity, but some individuals were classified as false negatives in the thoracic region and some false positives in the lumbar region. The AF ICC values set were similar or better than the ICC values of the gold standard, both intra and inter-evaluators. Further, the MAD values, SEM and MDC set AF were always lower than AC, whether in the lumbar or thoracic spine. The normal range in the thoracic region were 0.97 cm to 3.83 cm for f 20° to 50° for the AF adjusted. The normal range in the lumbar were: 0,37cm to 3.81cm to f of 23,06° to 53,60° for AF set. Conclusion: AF adjusted and f are valid and reliable for evaluating clhilren´s thoracic kyphosis and lumbar lordosis, showing strong correlation values with the gold standard, as well as good and excellent reliability values associated with low errors and variability of the measures, indicating be a tool accurately and reliable the evaluation of the spine.

Ten years have passed since Wal-Mart’s public announcement about its RFID technology adoption plan in 2003. Some large competitors of Wal-Mart in the U.S. retail industry jumped on the trend of RFID technology adoption. However, many U.S. retailers do not consider adopting RFID technology because of the uncertainty of return on investment and the lack of business cases demonstrating its profitability, productivity, or efficiency. This study investigates whether RFID companies have better financial performance ratios in the U.S. retail industry. RFID retailers have significantly higher operating margin, lower days-in-inventory, and lower per-employee costs. Compared with pre-RFID, the RFID retailers did not improve profit ratios after they adopted it, but their days-in-inventory ratio and sales efficiency improved significantly. Compared to small RFID retailers, large RFID retailers show greater inventory management efficiency and sales efficiency. Regression analyses show that inventory management efficiency does impact gross margins, but the impact of cost efficiency is negligible. RFID retailers have a positive relationship with gross margin increases. The regression analyses using the Cobb-Douglas production function show that the RFID retailers have a little higher labor productivity than non-RFID retailers. In summary, the analyses reveals that RFID retailers have a better record of maintaining an efficient inventory management and higher labor productivity, but more research is needed to demonstrate the relationship between cost efficiency and profitability.

<p>This thesis develops a computable, non-linear programming, general equilibrium model of the Canadian textile sector for the purpose of addressing certain trade policy issues.</p> <p>One of the unique features of the model is the specification of the objective function a CES nested in a Cobb-Douglas function. This objective function incorporates the assumption of diminishing marginal utility', an assumption which is almost universally accepted in microeconomic theory but which is conspicuously missing in linear programming models. This objective function also allows for imperfect substitutability between domestically produced textiles and imported textiles.</p> <p>The textile sector is significantly disaggregated to allow for the interconnections among the various textile industries in the sector. In addition, unlike partial equilibrium models which do not consider what happens to other industries outside the sector under study, this model is able to shed same light on the behaviour of these industries.</p> <p>The model is solved by an optimization package called MINOS (a modular in-core nonlinear optimization system) and then used to predict the 1979 variables to set a benchmark for the model. The model predicts most variables reasonably well.</p> <p>The results of the experiments confirm Bhagwati's concept of equivalence as applied to general equilibrium models. The results also show that if protection in textiles is removed, imports will pour in, leading to declines in output and employment in the textile industries. The finding that there is considerable anti-protection in the textile sector agrees with the view expressed by other writers. The results also show that, in general, a textile industry at a later stage of processing tends to expand if it is the only one protected and an industry at an early stage of processing tends to contact if it is the only one protected.</p> <p>Given any quota, its tariff equivalent can be computed using the model. With reference to tariffs and subsidies, the results show that one cannot say categorically that one means of protection is generally preferable to the other, a finding which is consistent with the trade distortions literature.</p> / Doctor of Philosophy (PhD)

Considerando as micorregiões do Censo Agropecuário de 1995-1996 e dos Censos Demográficos de 1991 e 2000, este trabalho estima, primeiramente, uma função de produção Cobb-Douglas. Para tal, controla-se o efeito dos preços regionais sobre o valor da produção. São levados em conta fatores tradicionais (mão-de-obra, terra, insumos químicos e capital) e o capital humano (nível de escolaridade formal e conhecimento de mercado). A estimativa foi obtida através do método de mínimos quadrados em três estágios &#150; MQ3E. O método se justifica pelo modelo econômico proposto ser um sistema de equações (estima-se também a demanda por capital e o custo relativo da utilização deste fator) e pela forte presença de heteroscedasticia na estimação em mínimos quadrados ordinários &#150; MQO. Em seguida, estima-se a Produtividade Total dos Fatores &#150; PTF por estado, verificando-se a contribuição relativa do capital humano. / Using data from the Agricultural Census of 1995-96 and the Demographic Censuses of 1991 and 2000, this dissertation first estimate a Cobb-Douglas production function. The value of production is calculated in order to control the effect of regional prices. Traditional factors (labor, land, fertilizers and capital) and human capital (years of schooling and market knowledge) are used as explanatory variables in the production function. The economic model is a simultaneous equations system that considers both decisions to produce and maximize profits. Results of the proposed economic model are obtained by using the three-stage least squares (3-SLS) method due to presence of heteroskedasticity. Afterwards, total productivity factor (TFP) is estimated to each of the Brazilian states and the relative contribution of human capital is analyzed.

The thesis deals with the mathematical modelling of economic processes, particulary production. Basic approach, models and methods of modelling concerning the mentioned area are described. Further, specific characterizations are investigated. Application of selected methods to typical examples is presented. In the final part models on concrete data are constructed.

The elasticity of factor substitution between capital and labor is a crucial parameter in many economic fields. However, despite extensive research, there is no agreement on its value. Utilizing 738 estimates from 41 studies published between 1961 and 2016, this paper provides the first meta-regression analysis of capital-labor substitution elasticities for the U.S. economy. We show that heterogeneity in reported estimates is driven by the choice of estimation equations, the modeling of technological dynamics, and data characteristics. Based on the underlying meta-regression sample and a "best practice" specification, we estimate a long-run elasticity in the range of 0.6 to 0.7. For all estimated elasticities the hypothesis of a Cobb-Douglas production function is rejected.

No description available.

This paper reviews the status quo of the empirical and theoretical literature on the determinants of the elasticity of substitution between capital and labor. Our focus is on the two-input constant elasticity of substitution (CES) production function. By example of the U.S., we highlight the distinctive heterogeneity in empirical estimates of σ at both the aggregate and industrial level and discuss potential methodological explanations for this variation. The main part of this survey then focuses on the determinants of σ. We first review several approaches to the microfoundation of production functions, especially the CES production function. Second, we outline the construction of an aggregate elasticity of substitution (AES) in a multi-sectoral framework and investigate its dependence on underlying sectoral elasticities. Third, we discuss the influence of the institutional framework on the determination of σ. The concluding section of this review identifies a number of potential empirical and theoretical avenues for future research. Overall, we demonstrate that the effective elasticity of substitution (EES), which is typically estimated in empirical studies, is generally not an immutable deep parameter but depends on a multitude of technological, non-technological and institutional determinants.

Submitted by PPG Odontologia (odontologia-pg@pucrs.br) on 2018-03-19T17:16:06Z No. of bitstreams: 1 FERNANDO_DE_OLIVEIRA_ANDRIOLA_DIS.pdf: 1889802 bytes, checksum: 4fbb8e2e462022c1c29eeda8628a848b (MD5) / Approved for entry into archive by Tatiana Lopes (tatiana.lopes@pucrs.br) on 2018-04-03T16:47:33Z (GMT) No. of bitstreams: 1 FERNANDO_DE_OLIVEIRA_ANDRIOLA_DIS.pdf: 1889802 bytes, checksum: 4fbb8e2e462022c1c29eeda8628a848b (MD5) / Made available in DSpace on 2018-04-03T16:52:03Z (GMT). No. of bitstreams: 1 FERNANDO_DE_OLIVEIRA_ANDRIOLA_DIS.pdf: 1889802 bytes, checksum: 4fbb8e2e462022c1c29eeda8628a848b (MD5) Previous issue date: 2018-01-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / The purpose of this study was to evaluate cervical lordosis and head posture changes using lateral cephalographs after bimaxillary orthognathic surgery for mandibular prognatism by null hypothesis. Twenty-five patients with skeletal class III dentofacial deformities (10 men, 15 women; mean age, 29.28 ? 8.22 years; range 18-48 years) were included in this prospective clinical study. Lateral cephalographs were taken in natural head position (NHP) 2 weeks before and 6 months after orthognathic surgery. The reproducibility of the radiographer?s technique of taking radiographs in NHP was investigated using a photographic method and found to be acceptable. All measurements for cervical lordosis (CV1/CV2; CV3/CV7; CV1/CV7), head posture (NSL/OPT; NSL/VER) and other cephalometric values (NSL/Go-Gn; NSL/Ocl; Overjet) were repeated three times by the same investigator at 2- week intervals and the average values of the three measurements were calculated to use in statistical analysis. Intraclass correlation coefficients (ICC) ranged between 0.996 to 1.000, demonstrating a high reliability of the measures. Statistically significant differences were found for CV3/CV7 (P=0.006) and CV1/CV7 (P=0.005) and no significant differences were identified in head posture for both cranio-cervical and cranio-vertical angles. The null hypothesis was rejected. Orthognathic surgery resulted in significant cervical lordosis extension, and a tendency for head extension could also be observed. / O objetivo deste estudo foi avaliar, por hip?tese nula, a lordose cervical e as altera??es da postura da cabe?a usando telerradiografias de perfil ap?s cirurgia ortogn?tica bimaxilar para corre??o de prognatismo mandibular. Vinte e cinco pacientes com deformidades dentofaciais esquel?ticas classe III (10 homens, 15 mulheres, idade m?dia entre 29,28 ? 8,22 anos, intervalo de 18-48 anos) foram inclu?dos neste estudo cl?nico prospectivo. As radiografias laterais dos pacientes foram obtidas na posi??o natural de cabe?a (PNC) 2 semanas antes e 6 meses ap?s a cirurgia ortogn?tica. A reprodutibilidade da t?cnica do radiologista para realizar as tomadas radiogr?ficas na PNC foi investigada usando um m?todo fotogr?fico e considerada aceit?vel. As medidas para lordose cervical (CV1/CV2; CV3/CV7; CV1/CV7), postura da cabe?a (NSL/OPT; NSL/VER) e outros valores cefalom?tricos (NSL/Go-Gn; NSL/Ocl; Overjet) foram repetidas tr?s vezes pelo mesmo investigador em intervalos de 2 semanas e os valores m?dios das tr?s medidas foram calculados para serem usados na an?lise estat?stica. Os coeficientes de correla??o intraclasse (ICC) variaram entre 0,996 e 1,000, demonstrando uma alta confiabilidade das medidas. Foram encontradas diferen?as estatisticamente significativas para CV3/CV7 (P=0,006) e CV1/CV7 (P=0,005). N?o foram identificadas diferen?as significativas na postura da cabe?a para os ?ngulos cr?nio-cervical e cr?niovertical. A hip?tese nula foi rejeitada. A cirurgia ortogn?tica resultou em aumento significativo da lordose cervical (extens?o) e tamb?m em uma tend?ncia ? extens?o da postura da cabe?a.

Thesis (M.Sc. (Plant protection)) --University of Limpopo, 2013. / Studies were initiated to investigate (1) the aggressiveness of the citrus nematode (Tylenchulus semipenetrans Cobb) isolates from two provinces in South Africa (2 experiements ) and (2) the biotype of T. semipenetrans in South Africa. In the aggressive study, isolates from Limpopo and Mpumalanga Provinces were used on Carrizo citrange (Citrus sinensis × Poncirus trifoliata) and rough lemon (Citrus jambhiri) seedling rootstocks under greenhouse conditions (18 experiements). Each seedling was inoculated with 0, 10 000, 20 000, 30 000 and 40 000 J2s of T. semipenetrans isolates, which were arranged in a randomised complete block design, with six replications. At 120 days, the reproductive factor of T. semipenetrans isolate from Mpumalanga Province was significantly higher than that from Limpopo Province. Similarly, due to its higher relative impact on the reproductive factor values, the Mpumalanga isolate reduced plant growth variables more than the Limpopo isolate. Consequently, the Mpumalanga isolate was viewed as being more aggressive than the Limpopo isolate, suggesting that there might be genetic variability and/or adaptation in populations from the two locations. A national study, comprising T. semipenetrans isolates from 18 citrus-producing district municipalities in South Africa was then initiated under greenhouse conditions using isolates from each district – for a total of 18 separate experiments. Three differential hosts, viz. rough lemon, P. trifoliata and olive (Olea europaea), served as treatments, arranged in a randomised complete block design, with 15 replications. Initially, an orchard was randomly selected in each of the six citrus-producing provinces, viz. Eastern Cape, KwaZulu Natal, Limpopo, Mpumalanga, North West and Western Cape. Three-month old differential host seedlings were inoculated with approximately 10 000 J2s of T. semipenetrans and allowed to establish and grow under greenhouse conditions. At 120 days, penetration indices and standardised reproductive potentials/g roots demonstrated that T. semipenetrans failed to reproduce and develop on olive, but reproduced and developed on the other two hosts. Using T. semipenetrans biotype classification system, findings suggested that the biotype in citrus-producing district municipalities was Poncirus biotype. This biotype reproduces on P. trifoliata and hybrid rootstocks, which therefore, suggested that trifoliate orange and its hybrid rootstocks were not suitable for use in managing population nematode densities of T. semipenetrans in South Africa. In conclusion, results of this study demonstrated that the South African T. semipenetrans biotype was Poncirus, which suggested different management decisions and strategies for the citrus industry with regard to the management of this nematode. / By National Research Foundation, National Department of Agriculture, Forestry and Fisheries and the Land Bank Chair of Agriculture − University of Limpopo,