Essays on firm dynamics in the Swedish wholesale trade sector

This thesis consists of a summary and five self-contained papers addressing dynamics of firms in the Swedish wholesale trade sector. Paper [1] focuses upon determinants of new firm formation in the Swedish wholesale trade sector, using two definitions of firms’ relevant markets, markets defined as administrative areas, and markets based on a cost minimizing behavior of retailers. The paper shows that new entering firms tend to avoid regions with already high concentration of other firms in the same branch of wholesaling, while right-of-the-center local government and quality of the infrastructure have positive impacts upon entry of new firms. The signs of the estimated coefficients remain the same regardless which definition of relevant market is used, while the size of the coefficients is generally higher once relevant markets delineated on the cost-minimizing assumption of retailers are used. Paper [2] analyses determinant of firm relocation, distinguishing between the role of the factors in in-migration municipalities and out-migration municipalities. The results of the analysis indicate that firm-specific factors, such as profits, age and size of the firm are negatively related to the firm’s decision to relocate. Furthermore, firms seems to be avoiding municipalities with already high concentration of firms operating in the same industrial branch of wholesaling and also to be more reluctant to leave municipalities governed by right-of-the- center parties. Lastly, firms seem to avoid moving to municipalities characterized with high population density. Paper [3] addresses determinants of firm growth, adopting OLS and a quantile regression technique. The results of this paper indicate that very little of the firm growth can be explained by the firm-, industry- and region-specific factors, controlled for in the estimated models. Instead, the firm growth seems to be driven by internal characteristics of firms, factors difficult to capture in conventional statistics. This result supports Penrose’s (1959) suggestion that internal resources such as firm culture, brand loyalty, entrepreneurial skills, and so on, are important determinants of firm growth rates. Paper [4] formulates a forecasting model for firm entry into local markets and tests this model using data from the Swedish wholesale industry. The empirical analysis is based on directly estimating the profit function of wholesale firms and identification of low- and high-return local markets. The results indicate that 19 of 30 estimated models have more net entry in high-return municipalities, but the estimated parameters is only statistically significant at conventional level in one of our estimated models, and then with unexpected negative sign. Paper [5] studies effects of firm relocation on firm profits of relocating firms, employing a difference-in-difference propensity score matching. Using propensity score matching, the pre-relocalization differences between relocating and non-relocating firms are balanced, while the difference-in-difference estimator controls for all time-invariant unobserved heterogeneity among firms. The results suggest that firms that relocate increase their profits significantly, in comparison to what the profits would be had the firms not relocated. This effect is estimated to vary between 3 to 11 percentage points, depending on the length of the analyzed period. 

Tratamento de soluções de cromo (III) por flotação a ar dissolvido

O presente trabalho estuda a viabilidade da utilização do processo de flotação a ar dissolvido (FAD) no tratamento de efluentes contendo cromo. Tal processo é analisado comparativamente à sedimentação. Urna revisão dos diferentes tipos de processos de separação ou de recuperação do cromo é, também, aqui apresentada. Soluções contendo 200 mg.l" de cromo tri ou hexavalente foram estudadas quanto às condições ideais de precipitação, às características de sedimentação e de flotação a ar dissalvido em regime descontínuo e contlnuo. Agentes poliméricos foram testados no intuito de melhorar as condições de clarificação. O processo de FAD foi o que apresentou melhores resultados no que se refere a cinética de separação sólido/líquido, e em termos de clarificação das soluções. Estudos de separação sólido/líquido de soluções contendo cromo VI foram feitos por estes dois processos empregando sulfato ferroso e sulfito de sódio como agentes redutores. A FAD mostrou ser eficiente para tratar as soluções quando reduzidas com sulfito de sódio. Porém, no caso da utilização do sulfato ferroso como redutor, o rendimento da FAD diminuiu no tratamento de soluções que continham sólidos suspensos acima de uma concentração crítica. Polímeros também foram empregados neste caso, e confirmaram sua atuação melhorando a cinética de separação sólido/líquido e como agentes que beneficiam a clarificação das soluções. Os resultados dos estudos de flotação por ar dissolvido em uma unidade contínua mostraram que é viavel a FAD sem agentes floculantes ou tensoativos. No entanto, estes aumentam os níveis de clarificação das soluções. Apenas os floculantes a base de amido mostraram-se ineficientes nesta aplicação. Conclui-se que o processo de FAD pode ser utilizado no tratamento de efluentes contendo cromo permitindo obter efluentes finais dentro dos padrões de emissão da legislação brasileira.

Efetividade da terapia fisica descongestiva na cicatrização de úlceras venosas

A venous ulcer is the most serious clinical manifestation of chronic venous failure, and the most frequent in lower limbs, accounting for 70% of all ulcers. Patients may suffer from this infirmity for several years without healing of the lesion if treatment is inadequate. The aim of this investigation was to verify the effectiveness of decongestive physical therapy in the healing of venous ulcers. This is a quasi-experimental, interventionist study, with paired, non-probabilistic sampling, composed of 50 patients divided into two groups: control and intervention, each composed of 25 patients. Both groups were identically treated for six months with daily dressings and the latter also underwent complex physical therapy consisting of a combination of the following techniques: manual lymphatic drainage, compression bandaging, lower limb elevation, myolymphokinetic exercises and skin care. The study was approved (Protocol no. 59/2007) by the Ethics Committee of the State University of Southeast Bahia. The Mann-Whitney and Chi-square tests were applied for data analysis. After statistical analysis the patients who underwent therapy showed a statistically significant difference with respect to wound contraction starting in the second month of treatment. Compared to the control, the intervention group showed a greater reduction in both pain and edema starting in the third and fourth month of therapy, respectively. To reinforce these findings, the mean percentage of tissue present at the base of the ulcer (granulation/fibrin ratio) was calculated. The intervention group showed greater granulation at the base of the ulcer compared to the control, significant from the second month of treatment on. It was observed in this study that lymphotherapy, when compared between the intervention and control groups, accelerated the healing process, and reduced pain and edema in the affected limbs. It is expected, therefore, that these results widen scientific knowledge and we suggest that this therapy be used 78 not only to reduce lymphedema, but also as a treatment option for venous ulcers, given its easy application and low cost. The data, therefore, demonstrated the importance of basic care on the part of a multiprofessional and transdisciplinary health team involved in the healing process of these infirmities, thereby contributing to better quality of life in these individuals

Influência do método pilates na força e atividade elétrica dos músculos respiratórios de idosas - ensaio clínico controlado randomizado

The reduction of physiological capacity present in the process of aging causes a marked decline in lung function. The exercise does promote several positive changes in the physical health of people and protect the cardiorespiratory function. The aim of this study was to investigate the effects of a program of Pilates exercices on the strengh and electrical activity of respiratory muscles of elderly. This is a randomized, controlled clinical trial, evaluating 33 elderly aged 65 and 80 (70.88 ± 4.32), healthy, sedentary, without cognitive impairment and able the practice physical activity. The sample was divided into two groups, one experimental group with 16 elderly women who did Pilates exercises and a control group (17) that was not submitted to the exercises, but received educational booklets on aging and health care. The elderly were evaluated initially and after a period of three months, taking into account the Maximal Inspiratory Pressure (MIP) and Maximal Expiratory Pressure (MEP), obtained by Manovacuometry and intensity of EMG activity was measured using the values of Root Mean Square (RMS) for the diaphragm and rectus abdominis muscles, during the course of diaphragmatic breathing and MIP maneuver. Data were analyzed using SPSS version 17.0. For all tests, we used a significance level or p value < 0.05 and confidence interval 95%. RMS in diaphragm and rectus abdominis muscles in both tests increased, but the data were significant for the rectus abdominis during diaphragmatic breathing (p = 0.03) and the diaphragm during the MIP maneuver (p = 0.01). There was no significant variation of the MIP and MEP. Pilates exercises were responsible for increasing the electrical activation of the diaphragm and rectus abdominis muscles in a group of healthy elderly, but had no influence on changes in strength of respiratory muscles

The Conway-Maxwell-Poisson-generalized gamma regression model with long-term survivors

In this paper, we proposed a flexible cure rate survival model by assuming the number of competing causes of the event of interest following the Conway-Maxwell distribution and the time for the event to follow the generalized gamma distribution. This distribution can be used to model survival data when the hazard rate function is increasing, decreasing, bathtub and unimodal-shaped including some distributions commonly used in lifetime analysis as particular cases. Some appropriate matrices are derived in order to evaluate local influence on the estimates of the parameters by considering different perturbations, and some global influence measurements are also investigated. Finally, data set from the medical area is analysed.

Métodos de diagnóstico não-invasivos para avaliação da insuficiência venosa dos membros inferiores

A avaliação clínica dos membros inferiores na insuficiência venosa por si só não identifica os sistemas envolvidos ou os níveis anatômicos, sendo necessários exames complementares. Esses exames podem ser invasivos ou não-invasivos. Os invasivos, como flebografia e pressão venosa ambulatória, apesar de terem boa acurácia, trazem desconforto e complicações. Dentre os não-invasivos, destacam-se: Doppler ultra-som de ondas contínuas, fotopletismografia, pletismografia a ar e mapeamento dúplex. O Doppler ultra-som avalia a velocidade do fluxo sangüíneo de maneira indireta. A fotopletismografia avalia o tempo de reenchimento venoso, fornecendo um parâmetro objetivo de quantificação do refluxo venoso. A pletismografia a ar permite quantificar a redução ou não da capacitância, o refluxo e o desempenho da bomba muscular da panturrilha. O dúplex é considerado padrão-ouro dentre os não-invasivos, porque permite uma avaliação quantitativa e qualitativa, fornecendo informações anatômicas e funcionais, dando avaliação mais completa e detalhada dos sistemas venosos profundo e superficial.

Testes em modelos weibull na forma estendida de Marshall-Olkin

In survival analysis, the response is usually the time until the occurrence of an event of interest, called failure time. The main characteristic of survival data is the presence of censoring which is a partial observation of response. Associated with this information, some models occupy an important position by properly fit several practical situations, among which we can mention the Weibull model. Marshall-Olkin extended form distributions other a basic generalization that enables greater exibility in adjusting lifetime data. This paper presents a simulation study that compares the gradient test and the likelihood ratio test using the Marshall-Olkin extended form Weibull distribution. As a result, there is only a small advantage for the likelihood ratio test

Low appendicular muscle mass is correlated with femoral neck bone mineral density loss in postmenopausal women

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of methyl methacrylate monomer on bond strength of denture base resin to acrylic teeth

Bond failures at the acrylic teeth and denture base resin interface are still a common clinical problem in prosthodontics. The effect of methyl methacrylate (MMA) monomer on the bond strength of three types of denture base resins (Acron MC, Lucitone 550 and QC-20) to two types of acrylic teeth (Biotone and Trilux) was evaluated. Twenty specimens were produced for each denture base resin/acrylic tooth combination and were randomly divided into control (acrylic teeth received no surface treatment) and experimental groups (MMA was applied to the surface of the acrylic teeth for 180 s) and were submitted to shear tests (1 mm/mm). Data (MPa) were analyzed using three-way ANOVA/Student's test (alpha = 0.05). MMA increased the bond strength of Lucitone denture base resins and decreased the bond strength of QC-20. No difference was detected for the bond strength of Acron MC base resin after treatment with MMA. (C) 2008 Elsevier Ltd. All rights reserved.

Caffeine effect on mortality and oviposition in successive generations of Aedes aegypti

OBJETIVO: Experimentos anteriores mostraram que a cafeína bloqueia o desenvolvimento de Aedes aegypti (Diptera, Culicidae) na fase larval, inibindo conseqüentemente a produção de adultos. O objetivo do estudo foi obter dados que pudessem sugerir desenvolvimento de resistência dos mosquitos à cafeína. MÉTODOS: Foi avaliada a produção de adultos em gerações sucessivas, a partir de ovos produzidos na geração anterior e a taxa de oviposição em cada geração, utilizando meios contendo cafeína a 200 e 500 µg/ml e água de torneira proveniente de poço artesiano como controle. Os experimentos foram conduzidos em São José do Rio Preto, entre 2002 e 2005. Nos testes estatísticos foram utilizados a análise exploratória de dados e algoritmos de alisamento. RESULTADOS: Ocorreu redução crescente da produção de adultos, nas duas concentrações, ao longo das gerações, mas apenas no experimento a 200 µg/ml os dados foram estatisticamente significantes. Quanto à oviposição, a análise dos números mostra redução crescente e acentuada na média de ovos por fêmea, no experimento tratado. CONCLUSÕES: Não houve evidência de resistência ao longo das gerações devido ao tratamento com cafeína. Os resultados encontrados podem reforçar a indicação da cafeína como uma alternativa aos principais agentes de controle do Ae. aegypti atualmente usados, contra os quais os mosquitos têm desenvolvido resistência.

The Geometric Birnbaum-Saunders regression model with cure rate

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito de diferentes sais de ferro sobre as características sensoriais do iogurte de soja

The soy-yogurt was used as food vehicle due to its therapeutic and nutritionalproperties and lower cost. The aim of this work was to develop an enriched soy-yogurt with 12 mg of elementary iron/1, with suitable sensory and technological properties. Four iron sources were tested: FeSO 4.7H 2O, NaFeEDTA, Ferrochel® and microencapsulated FeSO 4.7H 2O. The products were evaluated by fermentation time, pH, titratable acidity, viscosity, consistency, iron concentration and sensory properties (difference from the control and acceptance tests). Viscosity and consistency data were submitted to analysis of variance and Tukey's test. Difference from the control data was evaluated by analysis of variance and Dunnett's test and the acceptance test was evaluated by analysis of variance and Tukey's test. For all iron salts used in the enrichment process, only the FeSO 4JH 2O did not work out because of the undesirable sensorial characteristics of the final products. The others sources used in the enrichment process (NaFeEDTA, Ferrochel® and microencapsulated FeSO 4.7H 2O) did not alter the fermentation time, titratable acidity and sensory and reologics properties of the soy-yogurt.

Efeito da temperatura e tempo de austenitização nas transformações de fase da liga 13Cr2Ni0,1C

New classes of martensitic stainless steels, with low carbon levels, have been developed aiming to meet the needs of the petroleum industry segment. However, their use has been restricted due to the fact it is a recent development and many of its properties are still under investigation. This work determines the values of initial and final temperatures for the austenitic transformation and the initial and final temperatures of martensitic formation for alloy 13Cr2Ni0,1C, by means of dilatometric tests under continuous cooling. Based on these results the optimized conditions for quench and temper heat treatments were obtained. The microstructural characterization of the alloys under coarse fusion condition was carried out by optical microscopy and the presence of delta-ferrite in the martensitic matrix was observed.

Determination of critical velocity and anaerobic capacity of running rats

The aim of this study was to validate a non-invasive protocol to determine aerobic and anaerobic capacity of treadmill running rats. Thirteen male Wistar rats (90 days old) were submitted to 4 exercise tests, consisting of running at 25, 30, 35 and 40 m min-1, continuously until exhaustion. For the critical velocity (CV) and anaerobic running capacity (ARC) estimations, the hyperbolic curve (velocity versus time to exhaustion (tlim)) was linearized to V= CV+ARC/tlim, where the CV and ARC were linear and slope coefficients, respectively. In order to verify if the CV was the maximal aerobic intensity, the rats were submitted to the maximal lactate steady state test (MLSS) composed of three 25-minute tests of continuous running trials at 15, 20 and 25 m min-1, with blood collection every 5 minutes. The CV was obtained at 22.8±0.7 m min-1 and the ARC, at 26.80±2.77 m. The MLSS was observed at 20m min-1, with blood lactate 3.84 ± 0.31 mmol L-1. There was a progressive increase in lactate concentration at 25 m min-1. The CV and MLSS were different, but presented a high and significant correlation (r=0.81). These results indicate that the non-invasive protocol can be used for physical evaluation of aerobic running rats, but the ARC should still be further investigated.

Factors affecting the adoption of supply chain management practices: Evidence from the Brazilian electro-electronic sector

This study on the factors affecting the adoption of supply chain management (SCM) practices develops four hypotheses based on a literature review, and tests them using survey data of Brazilian electro-electronic firms. The results reveal the big picture of the SCM practices in the sector and suggest that contextual factors such as size, position and bargaining power affect the adoption of SCM practices, which are also more customer oriented. Sector characteristics are very important in analysing SCM practices. Contrary to the findings of literature, the relationship between competitive priorities and SCM practices was not supported statistically. © 2011.