No abstract

Introduction: Staphylococci are the most important agents associated with bovine mastitis. This study aimed at characterizing resistance factors to antimicrobials in Staphylococcus spp. isolated from the milk of cows with subclinical mastitis. Methodology: In vitro resistance of 243 Staphylococcus spp. isolates to antimicrobials commonly used in clinical practice was evaluated. The detection and expression of genes encoding resistance mecA (gene encoding penicillin binding protein 2a) mecALGA251 (mecA homologue), blaZ (gene encoding penicillin resistance), femA and femB (genes encoding essential factors - A and B - for the expression of methicillin resistance) and aacA-aphD (gene encoding for a bifunctional enzyme that confers resistance to gentamicin) using PCR and RT-PCR was investigated. Results: One or more genes encoding resistance to different antimicrobials were detected in 184 Staphylococcus spp. samples. The femA and femB genes were the most frequent. Regarding the variables’ detection (N = number of strains) and expression (% of strains), the following results were obtained: blaZ (N = 40 – 82.5%), femA (N = 147 – 47.6%), aacAaphD (N = 30 – 43.3%), femB (N = 138 – 29.7%), mecA (N = 33 – 27.3%), mecALGA251 (N = 01 – 0.0%). There was a higher occurrence of phenotypic resistant strains for amoxicillin, ampicillin and penicillin in isolates positive for detection and/or expression of blaZ gene when compared with the other genes. Conclusions: The present study provides new information on genotypic traits of Staphylococcus isolates from bovine subclinical mastitis especially regarding the evaluation of expression of genes associated with antimicrobial resistance in Staphylococcus spp. using molecular tools.

This article reports a study on the performance of mutual equity funds in Brazil from January 2002 to August 2012. For the analyses, Carhart's four-factor model is used as the benchmark for performance, and bootstrap procedures are applied to separate skill from luck. The results show that returns of the best performers are more due to luck than skill of their managers. For the bottom ranked funds, on the contrary, there is statistical evidence that their poor performance is caused mainly by bad management, rather than by bad luck. It is also showed that the largest funds perform better than the small or middle-sized funds. ResumoEste artigo analisou o desempenho dos fundos de investimento em ações no Brasil no período de janeiro de 2002 a agosto de 2012. A base para as análises foi o modelo de quatro fatores de Carhart, sobre o qual foram aplicados procedimentos de bootstrap a fim de separar habilidade de sorte nas análises. Os resultados indicaram que os retornos dos fundos de melhor performance se deveram mais à sorte do que propriamente da habilidade de seus gestores. Para os fundos de pior performance, pelo contrário, há evidência estatística de que seu mau desempenho foi causado principalmente pela má gestão, e não por azar. Os resultados indicaram também que os maiores fundos apresentaram desempenho superior ao dos fundos de pequeno e médio porte no período.

This study contributes to research on value investing in Brazil, analyzing the Brazilian funds that adopt this philosophy. The goal is to identify some of the factors that influence the decisions of value investing managers to maintain an asset in their portfolios. The results point out that the variables that influence portfolio managers to maintain a stock in their assets under management are greater stability in earnings per share, high ROA (Return on Assets), high gross margin, company size, and liquidity of the shares.

Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in AbstractThis article reports a study on the performance of mutual equity funds in Brazil from January 2002 to August 2012. For the analyses, Carhart's four-factor model is used as the benchmark for performance, and bootstrap procedures are applied to separate skill from luck. The results show that returns of the best performers are more due to luck than skill of their managers. For the bottom ranked funds, on the contrary, there is statistical evidence that their poor performance is caused mainly by bad management, rather than by bad luck. It is also showed that the largest funds perform better than the small or middle-sized funds. © 2014 National Association of Postgraduate Centers in Economics, ANPEC. Production and hosting by Elsevier B.V. All rights reserved. A base para as análises foi o modelo de quatro fatores de Carhart, sobre o qual foram aplicados procedimentos de bootstrap a fim de separar habilidade de sorte nas análises. Os resultados indicaram que os retornos dos fundos de melhor performance se deveram mais à sorte do que propriamente da habilidade de seus gestores. Para os fundos de pior performance, pelo contrário, há evidência estatística de que seu mau desempenho foi causado principalmente pela má gestão, e não por azar. Os resultados indicaram também que os maiores fundos apresentaram desempenho superior ao dos fundos de pequeno e médio porte no período.