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61.
Pelagic larvae are highly important for maintaining the gene flow among populations of sessile marine invertebrates. Colonial ascidians consist, exclusively, of brooding species, with lecithotrophic larvae that have a limited dispersal. As a result, there is a marked differentiation among populations. In this work, we used allozyme electrophoresis to access the genetic variation in four populations of Symplegma rubra, a colonial ascidian frequently found in the intertidal zone of Southeastern Brazilian coast. High variability was found at three of the four sites sampled, the exception being Praia Grande in the State of Rio de Janeiro. At this site, there was a great preponderance of clones, which possibly reflected the enclosed nature of the location and its low water circulation that reduce the dispersal capabilities of these animals. S. rubra did not conform to expectations for random mating (Hardy–Weinberg equilibrium): there was a deficit of heterozygotes that was more related to the small population size than to inbreeding processes, since F is analysis per locus revealed a deficiency of heterozygotes at only one locus—MDH*. The greatest variation in allele frequency was found for GPI-2*. Analyses of genetic variability revealed moderate differentiation among the populations (F ST=0.051), which was unexpected for a species with a low dispersal capability. Rafting, a frequently underestimated means of dispersal, may be the main mode of gene flow in this species over large areas, since colonies of S. rubra are frequently seen growing on drift material and there is no evidence that the larva survive for a long time in the plankton.  相似文献   
62.
Forty-two fetuses with non-homologous Robertsonian translocations were analyzed for uniparental disomy (UPD). One fetus with a de novo translocation t(13q;14q) had maternal isodisomy of chromosome 14. In a summary of the published data (including the present study), 315 cases were analyzed for UPD after prenatal diagnosis of balanced Robertsonian translocations, of these two fetuses had UPD, giving a risk estimate of 0.65% (CI 0.2–2.3). This risk justifies the recommendation of UPD analysis in fetuses diagnosed prenatally with Robertsonian translocations, with the emphasis on the chromosomes known to contain imprinted genes, such as 14 and 15. We also discuss the possibility of UPD in offspring of Robertsonian translocation carriers with normal karyotype. Based on the risk for UPD in fetuses with Robertsonian translocation we suggest to test these fetuses for UPD and to do so on amniocytes rather than chorionic villi when the risk for unbalanced karyotype is ∼1%, comparable to the risk for UPD. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
63.
Environmental Science and Pollution Research - One of the most widely used antibiotics is amoxicillin (AMX), which is the most widely used in humans and animals, but it is discharged metabolically...  相似文献   
64.
Environmental Science and Pollution Research - Microplastics (MPs) correspond to plastics between 0.1 μm and 5 mm in diameter, and these can be intentionally manufactured to be microscopic or...  相似文献   
65.
Journal of Polymers and the Environment - The objective of this study was to obtain and characterize Nerol essential oil encapsulated in PCL. The miniemulsion and solvent evaporation method was...  相似文献   
66.
A photocatalyst based on CuO/SiO2 was prepared, and evaluated for the degradation of methylene blue in aqueous medium. The photocatalyst was obtained by calcination method of copper salt, in the presence of silica. The characterization by XRD, FTIR, and TPR techniques confirmed the formation of CuO as active phase. SEM studies showed CuO deposited on the surface of SiO2. By ESI-MS, it was demonstrated that the degradation of methylene blue occurs through successive hydroxylations. Photodegradation assays showed that CuO/SiO2 was efficient for degradation, and that the material worked better in the presence of UV light.  相似文献   
67.
This paper details a case study of economic and natural system responses to alternative water management policies in the Cache La Poudre River basin, Colorado, 1980–1994. The case study is presented to highlight the value and application of a conceptual integration of economic, salmonid population, physical habitat, and water allocation models. Five alternative regimes, all intended to increase low winter flows, were investigated. Habitat enhancements created by alternative regimes were translated to population responses and economic benefits. Analysis concluded that instream flows cannot compete on the northern Colorado water rental market; cooperative agreements offer an economically feasible way to enhance instream flows; and establishing an instream flow program on the Cache La Poudre River mainstem is a potentially profitable opportunity. The alliance of models is a dynamic multidisciplinary tool for use in professional settings and offers valuable insight for decision-making processes involved in water management.  相似文献   
68.
Traditionally, in Spain bullfighting represents an ancient and well-respected tradition and a combined brand of sport, art and national identity. However, bullfighting has received considerable criticism from various segments of society, with the concomitant rise of the animal rights movement. The paper reports a survey of the Spanish citizens using a face-to-face survey during January 2016 with a total sample of 2522 citizens (1256 men and 1266 women). The survey asked about degree of liking and approving; culture, art and national identity; socio-economic aspects; emotional perception and animal welfare. The hypothesis proposed that the perception of bullfights may be affected by gender, age, occupation, origin and nationality of the persons surveyed. The hypothesis was confirmed. The majority of citizens surveyed do not like bullfights and great majorities do not attend or watch such events. Two extreme clusters were described: one representing favorable attitude towards bullfighting and other against bullfighting. The proportion of indifferent persons was important. Women and young people showed a more favorable attitude towards animal welfare issues associated with these events. Rural people were more accepting bullfights than urban people. Students were more anti-bullfight than those in other occupations. Additionally, technical economic factors made people favor more bullfights. The growth of claim against bullfights establishes an element of a far more multifaceted phenomenon that animal cruelty per se and support of a new paradigm called social change in countries as Spain.  相似文献   
69.
A population of the cosmopolitan deep-sea ophiuran Ophiomusium lymani was studied by gel electrophoresis, and proved to be highly variable genetically; about 53% of the 15 loci studied are polymorphic, and the average individual is heterozygous at about 17% of the loci. This is approximately the same genetic variability displayed by other species, belonging to other phyla or classes, from the same deep-sea trawl. A similarly high level of genetic variation occurs in deep-sea organisms in general, and in a shallow-water tropical species. Both the deep-sea and the tropics are trophically stable environments. On the other hand, low genetic variabilities have been found in marine species from trophically unstable environments. These data suggest that any phylogenetic effects on genetic variability are secondary, and that the trophic regime may be of major importance in determining genetic strategies of adaptation.This study is no. 5 of a series of reports on the results of Expedition Quagmire.  相似文献   
70.
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