Genetic differentiation in the populations of red piranha, Pygocentrus nattereri Kner (1860) (Characiformes: Serrasalminae), from the river basins of northeastern Brazil.

The red piranha, Pygocentrus nattereri, is an important resource for artisanal and commercial fisheries. The present study determines the genetic differentiation among P. nattereri populations from the northeastern Brazilian state of Maranhão. The DNA was isolated using a standard phenol-chloroform protocol and the Control Region was amplified by PCR. The PCR products were sequenced using the didesoxyterminal method. A sequence of 1039 bps was obtained from the Control Region of 60 specimens, which presented 33 polymorphic sites, 41 haplotypes, Ò» =0.978 and π =0.009. The neutrality tests (D and Fs) were significant (P < 0.05) for most of the populations analyzed. The AMOVA indicated that most of the molecular variation (72%) arises between groups. The fixation index was highly significant (FST = 0.707, P < 0.00001). The phylogenetic analyses indicated that the specimens represented a monophyletic group. Genetic distances between populations varied from 0.8% to 1.9%, and were <0.5% within populations. The degree of genetic differentiation found among the stocks of P. nattereri indicates the need for the development of independent management plans for the different river basins in order to preserve the genetic variability of their populations.

Genetic differentiation in the populations of red piranha, Pygocentrus nattereri Kner (1860) (Characiformes: Serrasalminae), from the river basins of northeastern Brazil / Diferenciação genética em populações da piranha vermelha, Pygocentrus nattereri Kner (1860) (Characiformes: Serrasalminae), em bacias hidrográficas do nordeste do Brasil

Abstract The red piranha, Pygocentrus nattereri, is an important resource for artisanal and commercial fisheries. The present study determines the genetic differentiation among P. nattereri populations from the northeastern Brazilian state of Maranhão. The DNA was isolated using a standard phenol-chloroform protocol and the Control Region was amplified by PCR. The PCR products were sequenced using the didesoxyterminal method. A sequence of 1039 bps was obtained from the Control Region of 60 specimens, which presented 33 polymorphic sites, 41 haplotypes, һ =0.978 and π =0.009. The neutrality tests (D and Fs) were significant (P < 0.05) for most of the populations analyzed. The AMOVA indicated that most of the molecular variation (72%) arises between groups. The fixation index was highly significant (FST = 0.707, P < 0.00001). The phylogenetic analyses indicated that the specimens represented a monophyletic group. Genetic distances between populations varied from 0.8% to 1.9%, and were <0.5% within populations. The degree of genetic differentiation found among the stocks of P. nattereri indicates the need for the development of independent management plans for the different river basins in order to preserve the genetic variability of their populations.

Resumo A piranha vermelha, Pygocentrus nattereri, é um recurso importante para pesca artesanal e comercial. O presente estudo determinou a diferenciação genética entre populações de P. nattereri no nordeste do estado brasileiro do Maranhão. O DNA foi isolado utilizando o protocolo de Fenol-clorofórmio e a Região Controle foi amplificada por PCR. Os produtos da PCR foram sequenciados usando o método didesoxiterminal. Uma sequência de 1039 pbs foi obtida da Região Controle de 60 espécimes, que apresentaram 33 sítios polimórficos, 41 haplótipos, һ= 0.978 e π= 0.009. Os testes de neutralidade (D and Fs) foram significativos (P < 0.05) para a maioria das populações analisadas. A AMOVA indicou que a maior parte da variação molecular (72%) surge entre os grupos. O índice de fixação foi altamente significativo (FST = 0.707, P = < 0.00001). As análises filogenéticas indicaram que os espécimes representam um grupo monofilético. Distâncias genéticas entre as populações variaram de 0.8% a 1.9%, e de <0.5% dentro das populações. O grau de diferenciação genética encontrada entre os estoques de P. nattereri indicam a necessidade para o desenvolvimento de planos de manejo independentes para as diferentes bacias hidrográficas, a fim de preservar a variabilidade genética dessas populações.

Modeling and controller performance assessment for a switched reluctance motor drive based on setpoint relay.

This paper considers the implementation of a current control method for switched reluctance motors (SRMs) and presents a novel approach to the accurate on-line modeling of an SRM drive. A simple autotuning technique for the SRM drives using a PWM controller is considered. Furthermore, conventional PI control and Internal Model Control (IMC) are considered to validate this method and present corresponding robust control analysis for the process. The control structures are comparatively analyzed using standard robustness measures for stability and performance. The proposed PWM controller is simulated and a hardware prototype is then implemented using digital signal processor control to evaluate the method using a 12/8, three-phase SRM. The experimental results of the SRM drive model validates the performance of the current loop.

[Pharmaceutical companies as sponsors of clinical trials--advantages and limitations]. / Firmas da indústria farmacêutica como patrocinadoras de ensaios clínicos--vantagens e limitações.

The therapeutic progress achieved in the second half of this century was made possible only due to the interest taken by the pharmaceutical industry in the research field. It can be considered as the primum movens of the therapeutic revolution which has strongly benefited the humanity in these last decades. The clinical trials of new drugs constitute an integral part of the pharmaceutical and medical research. However its complexity and the costs involved make its execution impossible without the help or sponsorship of the pharmaceutical firms. Even in the more advanced countries it would be unthinkable that clinical trials could be carried out without the assistance of the pharmaceutical industry. The sponsorship by the pharmaceutical firms turns the relationship doctor-firm into a symbiotic association as both the parties reap benefits thereof: the physician because he is able to satisfy his inquisitiveness and his interest for the clinical research and the pharmaceutical firm because through these trials it will collect the information it requires. Besides having to bear the expenses inherent to the research, the sponsoring firms equally contribute for other pursuits usually of academical character and of interest to the investigator. Therefore it is not rare that these firms assume the costs of presence of these investigators in scientific meetings or to contribute for the arrangements of such meetings or even subsidise the acquisition of the equipment for the hospital services, etc.--measures which in countries with poor investments in research sector, such as Portugal, may constitute the only possibility to be carried out.(ABSTRACT TRUNCATED AT 250 WORDS)