2,948 research outputs found
Diversificação fisiológica e morfológica de Micropogon furnieri (Desmarest, 1822) ao sul de Cabo Frio, Brasil
This paper deals with some aspects of faunistic diversification and refers to part of the distribution area of a sciaenid fish Micropogon furnieri (Desmarest, 1822) Jordan & Evermann 1884, widely distributed. Such species is characteristic of the tropical area and occurs along the Brazilian coast with highest abundance south of Cabo Frio. The analysis of variations of six meristic characters and eight body proportions and of some reproduction and growth features has shown that along the coast between latitudes 23ºS and 33ºS diversifi cation occurs within the species; such diversification implies in the existence of two populations, one occupying the area between 23ºS and 29ºS (area I) and the other between 29ºS and 33ºS (area II). The eco logical differences between the two mentioned areas according to our point of view is the reason for the species diversification in the whole area under observation. The differences recorded as the characteristics studied were suf ficient enough to illustrate the existence of two populations reproductively isolated suggesting that some gene exchange, if any, between both populations occurs in a very low rate. Our results show that abundance estimates of M. furnieri in this area must be made for each population as a whole until further studies on genetic characters are developed which may confirm the existence of gene exchange and if so, the gene flow rate. As the present study does not cover the total area of occurrence of Micropogon furnieri no hypothesis is extended to the general pattern of diversification (eventual presence of sub-species) and no systematic "status" and names are given to the populations identified
Estimativa da abundância relativa de corvina na costa centro-sul do Brasil
The aim of this paper is to evaluate the apparent abundance of the croaker (Micropogon furnieri) along the central and southern coast of Brazil (from 23º50'S to 35ºS). The data on catch and effort of the fish taken in the same area and at the same time, with different gear, are analysed from January 1959 to December 1962. The different gears used were reduced to the same level of efficiency, and the apparent abundance was estimated according to the fishing area (area I - from 23º50'S to 26ºS, and area II - from 26ºS to 35ºS), by quarters and by year. The results allow us to draw the following conclusions: 1 - There is a tendency of increase of the apparent abundance from the beginning to the end of each year and of decrease in following years, in both areas. The decrease is greater in area II. 2 - The levels of apparent abundance, in both areas, was very different. The level in area II is higher. 3 - Variations in the availability during the year, were observed. Data suggest that they are determined in area I by extrinsic factors, and in area II by intrinsic factors. 4 - Different responses of the stock, in both areas, to fishing intensity was verified, supporting the hypothesis of occurrence of two different croaker stocks. The stock of area I probably has reached a state of equilibrium with the fishery while in area II the stock has not yet reached this stage
Ictiofauna da baía de Santos: I. Sciaenidae (Percoidea, Percomorphi)
O presente trabalho constitui parte de um projeto a longo prazo que visa o estudo ecológico da fauna íctica da baía de Santos (23º58'S a 24º02'S 45º19'W a 46º24"W). Foi iniciado pelo levantamento da ictiofauna da região (etapa I) sendo que esta série tem a finalidade de possibilitar uma identificação rápida dos exemplares durante trabalhos de campo. Iniciamos essa série pelos Sciaenidae, por ser esta a família que possui o maior número de espécies representadas na região. Foram organizadas chaves para os gêneros e espécies, descrições sucintas das espécies, notas ecológicas sôbre as espécies em nossas águas, desenho e fotografia. Dos quinze gêneros de Sciaenidae marinhos que ocorrem no Brasil, nove gêneros foram registrados na baía de Santos; êsses nove gêneros encontram-se representados no Brasil por 21 espécies, tendo sido verificada a ocorrência de 12, na baía.Considering the great extension and the diversity of environmental conditions of the Brazilian coast, the study of the fauna of well-delimited regions seems to be advisable, as is the case of the region under study, namely the Bay of Santos, São Paulo, Brazil (from 23º58'S to 24º02'S; from 45º19'W to 46º24'W). This paper comprises part of a long-term program aiming at the ecological study of the ichthyological fauna of the Bay of Santos, which was initiated by the ichthyofauna of the region (1st part). The present series begins with the Scianidae since this is the family with a greater number of species represented in the region. As many as 21 species of 15 Sciaenidae genus recorded for the Brazilian waters, 9 occur in the Bay of Santos, represented by 12 species. Keys are given for the genus and species and also a brief description of the species, ecological notes for those recorded in Brazilian waters, drawings and photos
Micropogon furnieri: fecundidade e tipo de desova
Micropogon furnieri (Desmarest, 1822) Jordan, 1884 is one of the species of fish of commercial importance occurring along the southern coast of Brazil. It has been the subject of several studies and some aspects of its life cicle, behavior and abundance are already known. This is a contribution to the knowledge of some aspects of the reproduction of the species. The type of spawning is discussed and fecundity has been evaluated and shown to be dependent on body length, not on body weight
Migração da corvina, Micropogon furnieri, na costa sul do Brasil
The correlation between the latitude where denser concentrations of the croaker (Micropogon furnieri) occurred and the month of the year were established in this paper. The unit effort production (kg/hour haul) was used as the concentration index and the hauls made within 30' were grouped in the immediate superior latitude. The croaker migrates along the Brazilian coast between 28º S and 33º S, according to the expression: y = 30.6 + 1.85 cos 30 (x - 2), where: y = latitude (ºS) x = 1, 2 .... 12 (months of the year
Análise da pesca da corvina na costa centro-sul do Brasil
This paper presents results obtained in analysis of the data on catch and effort, for croaker (Micropogon furnieri) caught along the southern coast of Brazil, between 23º50'S and 35ºS, in a band of approximately 30 nautical miles, and landed at Santos from January 1959 to December 1962. The unweighted and weighted indexes of density and the concentration index were computed according to gear and to fishing area (I - from 23º50'S to 26ºS, and II - from 26ºS to 35ºS) and the data were grouped by quarters. The results suggest the following conclusions: 1) The croaker catch, to some extent, has been done without directive thus the fishing fleet has operated in the areas with density lower than average. 2) The level of unit-effort production differ largely between areas, suggesting the presence of two separate croaker populations. 3) The decrease in production per unit-effort year after year in the two areas, suggests a decrease in the relative abundance along the studied fishing area
Sôbre o desenvolvimento das ostras e possibilidades da ostreicultura nos arredores de Santos
Studies on wild oyster populations in the Santos region were started in March 1960, and in September of the same year work was begun on experimental culture. Several natural beds were found, the majority in the Bertioga Canal. Both the observations of wild populations and the experiments showed that the Canal is the most favorable location for oyster development. It was possible in the experimental work to show that both growth and survival rates are much higher there than they are in waters of higher salinity. Also the yield of meat per unit weight is higher in the Canal; about 1.5 g per centimeter of total length at the commercial size of approximately 8 cm. Two extended periods of fixation were found in the Canal, one in summer and the other from the end of winter through spring, although in the bay the fixation was practically year round. These results indicate good possibilities for a commercial oyster-culture industry. However, a bacteriological analysis of oysters from Canal beds showed coliform bacteria, so that provisions for purification should be made in any plans for development of oyster culture
Contribuição para o conhecimento da biologia de Cynoscion jamaicensis (Vaillant & Bocourt, 1883), na área entre Cabo de São Tomé (22º04's) e Torres (29º21'S), Brasil
Diel changes in food and feeding activity of sciaenid fishes from the South-western Atlantic, Brazil
El tipo de cambio paralelo constituye una de las principales variables económicas para la toma de decisiones en Venezuela. Para analizar el comportamiento de esta variable tomando en cuenta sus características inherentes, exceso de curtosis, persistencia y asimetría, se hace una síntesis teórica de los principales modelos estocásticos de volatilidad y, se estima un conjunto de modelos. El modelo que mejor ajusta el comportamiento de la variable es un EGARCH (1,1), que captura el efecto asimétrico de las perturbaciones estocásticas sobre la serie. Ante choques negativos (depreciación del tipo de cambio paralelo), la volatilidad asociada se incrementa, pero para choques positivos (apreciación del tipo de cambio paralelo), se mantiene constante
Four cases of progressive multifocal leukoencephalopathy in iatrogenic immunocompromised patients
Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS) caused by John Cunningham Virus (JCV). We report four PML cases in immunocompromised patients, respectively treated with (1) Natalizumab, (2) Rituximab, (3) autologous stem-cell transplantation, and (4) Tacrolimus. All patients underwent neurological examination, magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), JCV-DNA research on biological samples, and lymphocytes subpopulation study. All cases presented with motor, behavioural, and cognitive disorders. Visual, sensitive, and cerebellar deficits developed in three cases. MRI revealed widespread progressive demyelinating areas with active borders; three patients presented contrast enhancement. One patient developed inflammatory reconstitution syndrome (IRIS). At MRS, all cases presented decreased N-acetyl-aspartate (NAA) and three cases showed increased choline (Cho). In one patient, plasma and urine tested positive for JCV-DNA, while cerebrospinal fluid (CSF) analysis confirmed JCV in two patients. The fourth patient had a low JCV-DNA blood titer and brain biopsy showed subacute necrosis. Two patients had abnormal lymphocyte subpopulations. Three patients underwent therapy with Mirtazapine, one of whom received Mefloquine in add-on. No clinical response was registered. Clinical onset, MRI and MRS were highly suggestive of PML in all patients, despite three cases presented contrast enhancement. In three cases JCV-DNA detection in biological samples confirmed the diagnosis. The fourth patient fulfilled diagnosis of “presumptive PML”. Our data confirm the importance to complete the diagnostic workup despite the presence of findings not completely consistent with classical PML. We hypothesize that atypical characteristics could due to the clinical conditions leading to PML
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