Levantamento planorbídico do Estado de São Paulo (Brasil): 4ª Região Administrativa Planorbidic survey of the 4th Administrative Region of the State of S. Paulo, Brazil

A fim de conhecer a distribuição dos hospedeiros intermediários de S. mansoni no Estado de São Paulo (Brasil), a Superintendência de Controle de Endemias (SUCEN) procedeu a amplo inquérito malacológico em todos os municípios paulistas que teve a duração de 4 anos. As pesquisas realizadas na 4ª Região Administrativa que tem sede em Sorocaba e que constituem o objeto do presente relato, mostraram que Biomphalaria tenagophila (d'Orbigny, 1835) ocorre em 26 dos 59 municípios nela compreendidos. Biomphalaria glabrata (Say, 1818) é encontrada em 9 municípios e Biomphalaria straminea (Dunker, 1848), em 2. Vários casos de esquistossomose em migrantes já foram observados na área estudada. B. tenagophila parece estar implicada na cadeia natural de transmissão de S. mansoni em Itu e em São Roque, municípios em que foram descobertos os dois únicos casos da doença, até agora considerados como autóctones em toda a região.<br>In order to discover the actual distribution of the intermediate hosts of Schistosoma mansoni in the State of São Paulo, Brazil, a planorbidic survey was made in the 572 counties of the State. Investigation carried out in the State's 4th Administrative Region, which comprises 59 counties, has shown that Biomphalaria tenagophila (d'Orbigny, 1835), Biomphalaria glabrata (Say, 1818) and Biomphalaria straminea (Dunker, 1848) are found, respectively, in twenty nine, nine and two of the counties. Many cases of schistosomiasis were detected among migrants to the Region but, up to the present, only two patients - at Itu and São Roque - could have contracted, the disease in the studied area. It seems that the fluke was intermediated by B. tenagophila

Negative Capacitance of an Electrolytic Cell in the Absence of Bias Potential

We extend the Poisson-Nernst-Planck model to the case of an electrolytic cell limited by ohmic electrodes that are partially polarizable with different affinities for anions and cations. We show that the finite conductivity of the electrodes in combination with the different ionic diffusion coefficients for anions and cations may give rise to negative capacitance behavior of the cell impedance in the absence of any bias. The range where the negative capacitance character of the electrolytic cell appears is localized. When ambipolar diffusion and electrode polarization effects are simultaneously present, the real part of the electrical impedance shows up to three plateau