995 resultados para Marine observation
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The objective of this work was to estimate the genetic variability level and distribution in Brazilian broodstocks of marine shrimp (Litopenaeus vannamei). Nine of the country's largest hatcheries were evaluated using codominant and highly polymorphic microsatellite markers. The results obtained from genotyping of ten microsatellite loci are indicative of genetic variability that is compatible with that found in wild populations of L. vannamei in Mexico and Central America. A possible explanation is the highly diversified and relatively recent origin of the available broodstocks. Bayesian analysis detected a signal for five founding populations. The distribution of genetic distances partially reflects geographical location, and this information will be useful for the creation of new broodstocks. Therefore, L. vannamei genetic variability among nine of the largest national hatcheries can be considered high.
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The objective of this work was to evaluate the growth of the mangrove oyster Crassostrea gasar cultured in marine and estuarine environments. Oysters were cultured for 11 months in a longline system in two study sites - São Francisco do Sul and Florianópolis -, in the state of Santa Catarina, Southern Brazil. Water chlorophyll-α concentration, temperature, and salinity were measured weekly. The oysters were measured monthly (shell size and weight gain) to assess growth. At the end of the culture period, the average wet flesh weight, dry flesh weight, and shell weight were determined, as well as the distribution of oysters per size class. Six nonlinear models (logistic, exponential, Gompertz, Brody, Richards, and Von Bertalanffy) were adjusted to the oyster growth data set. Final mean shell sizes were higher in São Francisco do Sul than in Florianópolis. In addition, oysters cultured in São Francisco do Sul were more uniformly distributed in the four size classes than those cultured in Florianópolis. The highest average values of wet flesh weight and shell weight were observed in São Francisco do Sul, whereas dry flesh weight did not differ between the sites. The estuary environment is more promising for the cultivation of oysters.
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The objective of this work was to isolate strains of lactic acid bacteria with probiotic potential from the digestive tract of marine shrimp (Litopenaeus vannamei), and to carry out in vitro selection based on multiple characters. The ideotype (ideal proposed strain) was defined by the highest averages for the traits maximum growth velocity, final count of viable cells, and inhibition halo against nine freshwater and marine pathogens, and by the lowest averages for the traits duplication time and resistance of strains to NaCl (1.5 and 3%), pH (6, 8, and 9), and biliary salts (5%). Mahalanobis distance (D²) was estimated among the evaluated strains, and the best ones were those with the shortest distances to the ideotype. Ten bacterial strains were isolated and biochemically identified as Lactobacillus plantarum (3), L. brevis (3), Weissella confusa (2), Lactococcus lactis (1), and L. delbrueckii (1). Lactobacillus plantarum strains showed a wide spectrum of action and the largest inhibition halos against pathogens, both Gram-positive and negative, high growth rate, and tolerance to all evaluated parameters. In relation to ideotype, L. plantarum showed the lowest Mahalanobis (D²) distance, followed by the strains of W. confusa, L. brevis, L. lactis, and L. delbrueckii. Among the analyzed bacterial strains, those of Lactobacillus plantarum have the greatest potential for use as a probiotic for marine shrimp.
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A new Early Triassic marine fauna is described from the Central Oman Mountains. The fauna is Griesbachian in age, on the basis of abundant conodonts and ammonoids, and was deposited in an oxygenated seamount setting off the Arabian platform margin. It is the first Griesbachian assemblage from a well-oxygenated marine setting and thus provides a test for the hypothesis that widespread anoxia prevented rapid recovery. The earliest Griesbachian (parvus zone) contains a low-diversity benthic fauna dominated by the bivalves Promyalina and Claraia. A similar level of recovery characterizes the immediate postextinction interval worldwide. However, the middle upper Griesbachian sedimentary rocks (isarcica and catinata zones) contain an incredibly diverse benthic fauna of bivalves, gastropods, articulate brachiopods, a new undescribed crinoid, echinoids, and ostracods. This fauna is more diverse and ecologically complex than the typical middle to late Griesbachian faunas described from oxygen-restricted settings worldwide. The level of postextinction recovery observed in the Oman fauna is not recorded elsewhere until the Spathian. These data support the hypothesis that the apparent delay in recovery after the end-Permian extinction event was due to widespread and prolonged benthic oxygen restriction: in the absence of anoxia, marine recovery is much faster.
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Compared to synthetic aperture radars (SARs), the angular resolution of microwave radiometers is quite poor. Traditionally, it has been limited by the physical size of the antenna. However, the angular resolution can be improved by means of aperture synthesis interferometric techniques. A narrow beam is synthesized during the image formation processing of the cross-correlations measured at zero-lag between pairs of signals collected by an array of antennas. The angular resolution is then determined by the maximum antenna spacing normalized to the wavelength (baseline). The next step in improving the angular resolution is the Doppler-Radiometer, somehow related to the super-synthesis radiometers and the Radiometer-SAR. This paper presents the concept of a three-antenna Doppler-Radiometer for 2D imaging. The performance of this instrument is evaluated in terms of angular/spatial resolution and radiometric sensitivity, and an L-band illustrative example is presented.
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Remote diagnostics has become very popular in marine industry. Diagnostic systems are improved all the time and the newest monitoring systems are constantly taken into operation. Most vessels are, however, rigged up by outmoded facilities, which should be updated. In this work the principles of operating of such a remote diagnostic system as the ABB's third generation remote diagnostic system (RDS) and the newest Propulsion Condition Management System (PCMS) are studied. As a result of the thesis the ways of upgrading the old systems of RDS are presented. Specifically, the work focuses on the establishment of the connection between Advant controller AC-110 from the old system and PCMS server, and in other words how to get Modbus data by OPC server.
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Actinobaculum schaalii is a new species that has so far been isolated from human blood, urine and pus. Its importance has probably been underestimated and other Actinobaculum spp. may also have been underdiagnosed. This retrospective study comprises all known cases of A. schaalii infections identified since 2004 in the canton of Neuchâtel (170,000 inhabitants), Switzerland. Strains were cultivated and isolated in the bacteriology laboratory using its routine procedure. Identification included a Rapid ID 32 A strip (bioMérieux) and 16S rRNA gene sequencing. Twenty-one positive samples were found in 19 patients (11 male, 8 female) of all ages (range 16-91 years): 10 from urine (50%), six from blood (30%), one from both blood and urine (5%), and three from pus (15%). Thirteen out of 17 (76%) cases with either blood or urine specimens had underlying genitourinary tract pathologies. When urine cultures were positive for A. schaalii, leucocytes were found in all samples (10/10, 100%) but all nitrite tests were negative (10/10, 100%). The onset of appropriate treatment was delayed due to the diminished sensitivity of A. schaalii to the antibiotics commonly used for UTIs (i.e. ciprofloxacin and trimethoprim/sulfamethoxazole) and to the delay in microbiological diagnosis. A. schaalii should specifically be searched in all cases of leukocyturia with a negative nitrite test but with Gram-positive rods in the Gram stain, in patients with underlying genitourinary tract pathology, instead of dismissing these findings as clinically irrelevant colonization by coryneform bacteria. This infection may be much more common than previously thought.
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Alpine flora and climate change: monitoring of three summits in Valais (Switzerland) during the 20th century Climate change might trigger an upward shift of the flora in the Swiss Alps, especially since these experienced higher change in average than observed on a global scale. Previous investigations in the canton des Grisons (Switzerland) and Austria have revealed an increase of floristic diversity on alpine summits since the beginning of the 20th century. Three summits in Valais were revisited in this study: the Gornergrat (first inventory in 1919), the Torrenthorn (about in 1885) and the Beaufort (about in 1920). Every summit was newly inventoried in 2003 in the framework of the PERMANENT.PLOT.CH project. All showed a strong increase in species richness. On the Gornergrat (3135 m), 16 species were not found anymore, but 35 new ones were observed. The number of species on this exceptionally rich summit rose from 102 to 121. In comparison, the floristic richness increased from 24 to 63 species on the Torrenthorn (2924 m) and from 16 to 48 species on the Beaufort (3048 m). As in previous studies, this increase seems likely to be associated with climate change: the new species prefer, in average, higher temperature conditions than those previously prevailing on the summits. On the Gornergrat and Beaufort, our observations reveal a development of alpine meadows, whereas species typical of rocks and raw soils are predominantly colonising the Torrenthorn. This difference might be related to the important damage caused by wanderers on the vegetation of the Torrenthorn.
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Référence bibliographique : Rol, 59050
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The present study describes the ultrastructure of the mature spermatozoon of Lecithocladium excisum (Rudolphi, 1819) (Digenea: Hemiuroidea: Hemiuridae) from the stomach of the marine teleost Scomber japonicus Houttuyn (Scombridae) captured in the Atlantic Ocean, off Dakar (Senegal). The ultrastructural organization of the spermatozoon of L. excisum follows the general model described in most digeneans. It presents two axonemes of the 9+'1' pattern of the Trepaxonemata, nucleus, mitochondrion and parallel cortical microtubules, among other characters. However, some particularities of the spermatozoon of L. excisum are (i) the presence of a membranous ornamentation not associated with cortical microtubules in its anterior extremity, (ii) the presence of a very reduced number of cortical microtubules located only in the ventral side of the spermatozoon and (iii) the absence of several structures described in most digeneans such as spine-like bodies and cytoplasmic expansions.
Resumo:
The present study describes the ultrastructure of the mature spermatozoon of Lecithocladium excisum (Rudolphi, 1819) (Digenea: Hemiuroidea: Hemiuridae) from the stomach of the marine teleost Scomber japonicus Houttuyn (Scombridae) captured in the Atlantic Ocean, off Dakar (Senegal). The ultrastructural organization of the spermatozoon of L. excisum follows the general model described in most digeneans. It presents two axonemes of the 9+'1' pattern of the Trepaxonemata, nucleus, mitochondrion and parallel cortical microtubules, among other characters. However, some particularities of the spermatozoon of L. excisum are (i) the presence of a membranous ornamentation not associated with cortical microtubules in its anterior extremity, (ii) the presence of a very reduced number of cortical microtubules located only in the ventral side of the spermatozoon and (iii) the absence of several structures described in most digeneans such as spine-like bodies and cytoplasmic expansions.
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Collection : Archives de la linguistique française ; 202