A quantitative study of Vibrio parahaemolyticus (Sakazaki et al) in Etroplus suratensis (Bloch) and Metapenaeus dobsoni (Miers) from Cochin backwater

Seasonal variation of Vibrio parahaemolyticus in fish (Etroplus sauratensis) and prawn (Metapenaeus dobsoni) was monitored from March 1982 to February 1983. Analyses of total viable count, vibrio-like organisms, V. parahaemolyticus like organisms and V. parahaemolyticus showed that they occur more in prawn than in fish. In a more polluted environment, the counts of V. parahaemolyticus associated with fish were found to be higher than in prawn.

Contribución al conocimiento biológico del calamar argentino Illex illecebrosus argentinus

The present work deals with the biological study of the squid Illex illecebrosus argentinus of the Buenos Aires area (Argentina) in the southwest Atlantic ocean. According to recent research (Voss, pers. comm.) the squid obtained in commercial fishing in the waters off Buenos Aires Province (Castellanos), which in proper of the S.W. Atlantic. The material studied comes from commercial fishing done in in two sectors: one ranging from 36~' to 37~' S, and the other from 39~' to 42~' S in latitude, while both extend from 55~' to 62~' W in longitude. The fishing area varies during the years, being located more towards the North in summer and more towards the South in winter, following the fishing of hake. The number of individuals studied was 186. Their total length ranged from 195 mm to 670 mm for both sexes. The sampling showed that the males had lesser length and weight than the females: that is, a secondary sexual dimorphism was observed. At the length of 240 mm the squid reaches its sexual maturity. Sexual activity is observed the year around, but not simultaneously for the whole population, that is to say, spawning does not take place en masse but, on the contrary, it occurs during a prolonged period. In summer, from December to March, the greatest spawning period is observed. This takes place in the same habitat for the whole squid population. The squid herein studied is a cold water species, the water temperature ranging from 5~' to 12~' C in the sites of the largest catches. The squid is caught at depths ranging from 7 to 250 meters with a trawl net. In Patagonian waters, somewhat smaller individual are caught with 'poteras' at depths ranging from 1 to 8 fathoms.

Contribución al estudio biológico de Loligo brasiliensis Bl

A total of 592 individuals of Loligo brasiliensis from the Mar del Plata coastal fishing area (Buenos Aires prov., Argentina) have been studied during the 1961-1964 period. From a morphological point of view the population appears to be uniform and homogeneus. A brief description of this species is given in this paper since references in the literature are scarce from the time at which Blainville (1923) first described it. The only further references are found in D'Orbigny (1835), and Ferrusac (1839), and in Hoyle (1886), and Tyron Pilsbry (1879). In this paper the species was mentioned only as a bibliographical reference on morphological or biological conditions has been found in the literature. The distribution of this species ranges from Cuba, Brazil, Uruguay to the Argentine coast, probably down to the Gulf of San Jorge. The samples had been studied with respect to various body measurements by classifing the individuals in total length classes, since body length was considered the most significant measurement. The condition factor K has been calculated for different sexes and ages, for the various length classes. The results lead to the conclusion that the smaller the length the higher is the value obtained for K and viceversa. This is due to the fact that the length of the tentacle increases considerably with increasing size. Since the tentacle are quite light the factor K diminishes accordingly. The condition factor increases considerably from December to April with an average of 0.42, decrease and becomes stable from March to October, with an average of 0.30. This is a consequence of the ripening of the sex glands. The sex-ratios are as following: year 1961, 42 % female, 42 % male; year 1962, 51 % female, 45 % male; year 1963, 46 % female, 53 % male; year 1964, 26 % female, 42 % male, 32 % indif. The great percentage of 72 undifferentiated young individuals in the 1964 (March) sampling increases the ratio of undifferentiation. A short morphological description of both ovules and spermatozoos is given. An examination of the sex glands leads to the following conclusions: a) male and female sex gland in a preparatory stage during the whole year; b) the highest percentage of ripe glands is found through, November-March; e) the spawning appears to precede rather slowly, but this certain since the spawning environment does not coincide with the natural habitat of the species. Few spawning individuals were found; d) sexual differentiation begins at body lenght from 30 to 40 mm; i.e. a total length of approximately 145 mm. At a body length of 70 mm. the hectocotilication (sexual character) begins to appear. In June 1962, a sample gathered at Rawson (Chubut) was analyzed. The conclusion was reached that the sex glands in this population are in an earlier stage of development in comparison with those from the Mar del Plata area. Also the average for the factor K which were found to be 0.17 for females and 0.19 for male, are rather low for that date. These physiological facts are possibly related to morphological differences which will be pointed out in a forthcoming publication. Some very typical associations with Artemesia longinaris and Percophis brasiliensis were found. Cannibalism has been observed.

Three-dimensional distribution of Al in high-k metal gate: Impact on transistor voltage threshold

The three-dimensional spatial distribution of Al in the high-k metal gates of metal-oxide-semiconductor field-effect-transistors is measured by atom probe tomography. Chemical distribution is correlated with the transistor voltage threshold (VTH) shift generated by the introduction of a metallic Al layer in the metal gate. After a 1050 °C annealing, it is shown that a 2-Å thick Al layer completely diffuses into oxide layers, while a positive VTH shift is measured. On the contrary, for thicker Al layers, Al precipitation in the metal gate stack is observed and the VTH shift becomes negative. © 2012 American Institute of Physics.

应变异质结构(InGaAs/Al)GaAs材料的分子束外延生长.性质及其相关器件的研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z