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21.
We present a family who sought prenatal diagnosis in order to bear a healthy child to serve as an HLA–identical bone marrow donor for their son affected with Wiskott–Aldrich syndrome. They intended to abort HLA-incompatible fetuses who would have been unsuitable bone marrow donors. This case led us to conclude that prenatal diagnosis should not be used to benefit a third party or facilitate the conception or abortion of a fetus for the purpose of generating an organ for transplantation. The limits of parental autonomy and physician responsibility are discussed.  相似文献   
22.
Little is known about what limits genetic exchange in highly vagile, open ocean vertebrate species, such as the swordfish Xiphias gladius L. Reduced abundance of swordfish in some regions, and increased fishing pressure in others, has raised concerns and fueled interest in a more complete evaluation of the resource. In this study, global population structure in swordfish was assessed by sequencing a 300 base pair segment of the 5 end of mitochondrial DNA control region from 159 swordfish collected in three ocean basins: the Mediterranean, Atlantic and Pacific, over the years 1988 to 1994. Among the 159 individuals, 95 polymorphic sites delineated 121 unique haplotypes, indicating a high level of polymorphism on a global scale. A phylogenetic analysis of the unique DNA haplotypes revealed two divergent clades with differing geographic distributions. Phylogeographic concordance of this pattern with that of two other pelagic fish species suggests a biogeographic explanation for this structure. An analysis of molecular variance (AMOVA) revealed significant geographic partitioning of molecular variation among the three ocean basins, indicating that swordfish populations are structured on a global scale. Estimates of genetic exchange among populations within an ocean basin were high, indicating panmixia within ocean basins. Since the haplotypic diversity exhibited by the swordfish control regions is extremely high, much larger sample sizes may be necessary to detect subdivision within ocean basins.  相似文献   
23.
Huang KC  Zhao Z  Hoag GE  Dahmani A  Block PA 《Chemosphere》2005,61(4):551-560
This study investigated the extent and treatability of the degradation of 59 volatile organic compounds (VOCs) listed in the EPA SW-846 Method 8260B with thermally activated persulfate oxidation. Data on the degradation of the 59 VOCs (in mixture) reacted with sodium persulfate in concentrations of 1 g l(-1) and 5 g l(-1) and at temperatures of 20 degrees C, 30 degrees C, and 40 degrees C were obtained. The results indicate that persulfate oxidation mechanisms are effective in degrading many VOCs including chlorinated ethenes (CEs), BTEXs and trichloroethanes that are frequently detected in the subsurface at contaminated sites. Most of the targeted VOCs were rapidly degraded under the experimental conditions while some showed persistence to the persulfate oxidation. Compounds with "CC" bonds or with benzene rings bonded to reactive functional groups were readily degraded. Saturated hydrocarbons and halogenated alkanes were much more stable and difficult to degrade. For those highly persulfate-degradable VOCs, degradation was well fitted with a pseudo first-order decay model. Activation energies of reactions of CEs and BTEXs with persulfate were determined. The degradation rates increased with increasing reaction temperature and oxidant concentration. Nevertheless, to achieve complete degradation of persulfate-degradable compounds, the systems required sufficient amounts of persulfate to sustain the degradation reaction.  相似文献   
24.
Three Greenland sharks (Somniosus microcephalus) were tagged with electronic tags, in Baie St. Pancrace, St. Lawrence Estuary, Quebec, Canada. One shark was tagged on 23 July 2004, with an acoustic telemetry tag. Two sharks were each tagged with a pop-up satellite archival tag (PSAT) on 27 August 2004. Two of the sharks remained in or close to the bay, one for 47 days and the other for at least 66 days. The third shark left the bay immediately after tagging on 27 August 2004. This shark entered the main channel of the St. Lawrence Estuary, and had moved 114.9 km upstream by 1 November 2004 when the tag reported to ARGOS satellites. The tags provided a total of 179 days of data on the movement and environmental preferences of Greenland sharks in the St. Lawrence Estuary. Sharks that reported depth and ambient water temperature data from the bay showed significant diel differences in depth preferences and corresponding ambient temperatures. The sharks remained near the bottom of the water column during the day and displayed increased vertical movements at night. The shark that resided in the main channel did not show this pattern, but generally remained at depths between 325 and 352 m. Sharks in the bay experienced water temperatures that ranged from −1.1 to 8.6°C at depths from 0 to 67 m. In the main channel the shark experienced temperatures that ranged from 1.0 to 5.4°C at depths from 132 to 352 m. This is the first report of numerous Greenland sharks inhabiting shallow near shore bays during summer and autumn.  相似文献   
25.
High-resolution satellite locations were obtained from striped marlin using Argos transmitters attached to the upper lobe of the caudal fin. Twenty-six striped marlin were tagged off New Zealand (2005–2007) and tracked as far as the central Pacific Ocean. Caudal fin mounted Argos tags generated 1,524 locations during a total of 659 tracking days [mean 25 (±21.24) days per fish and 2.3 (±2.30) locations per day]. 38% of locations have an estimated accuracy of ±1 km or better. Displacement rates from high quality locations ranged from 2.9 to 170.8 km in a 24 h period, with a mode at 20–30 km and a mean of 45 km/day. The caudal fin attachment methodology and antenna configuration was adjusted each season to improve transmission life and data quality, with the best results obtained in the last year of deployments (2007). The longest track duration was 102 days, with a total displacement of 4,959 km and a total track distance from all locations received of 6,850 km. Tag shedding and antenna failure appear to have limited the duration of tracks from SPOT tags. The high temporal and spatial resolution data revealed behaviours not previously observed in striped marlin, including associations to subsurface bathymetric features. High resolution location data such as these are useful inputs for statistical models used to investigate habitat selection and switching between different behavioural modes. The geolocations calculated using ukfsst estimates from PAT tag data had RMS errors of 1.01° latitude and 0.59° longitude when compared with SPOT tag Argos locations.  相似文献   
26.
27.
Large marine protected areas (MPAs) of unprecedented size have recently been established across the global oceans, yet their ability to meet conservation objectives is debated. Key areas of debate include uncertainty over nations’ abilities to enforce fishing bans across vast, remote regions and the intensity of human impacts before and after MPA implementation. We used a recently developed vessel tracking data set (produced using Automatic Identification System detections) to quantify the response of industrial fishing fleets to 5 of the largest MPAs established in the Pacific Ocean since 2013. After their implementation, all 5 MPAs successfully kept industrial fishing effort exceptionally low. Detected fishing effort was already low in 4 of the 5 large MPAs prior to MPA implementation, particularly relative to nearby regions that did not receive formal protection. Our results suggest that these large MPAs may present major conservation opportunities in relatively intact ecosystems with low immediate impact to industrial fisheries, but the large MPAs we considered often did not significantly reduce fishing effort because baseline fishing was typically low. It is yet to be determined how large MPAs may shape global ocean conservation in the future if the footprint of human influence continues to expand. Continued improvement in understanding of how large MPAs interact with industrial fisheries is a crucial step toward defining their role in global ocean management.  相似文献   
28.
Mark-recapture techniques can be used to estimate white shark (Carcharodon carcharias) population abundance. These frameworks are based on assumptions that marks are conserved and animals are present at the sampling location over the entire duration of the study. Though these assumptions have been validated across short-time scales for white sharks, long-term studies of population trends are dependent on these assumptions being valid across longer periods. We use 22 years of photographic data from aggregation sites in central California to support the use of dorsal fin morphology as long-term individual identifiers. We identified five individuals over 16–22 years, which support the use of dorsal fins as long-time individual identifiers, illustrate strong yearly site fidelity to coastal aggregation sites across extended time periods (decades), and provide the first empirical validation of white shark longevity >22 years. These findings support the use of fin morphology in mark-recapture frameworks for white sharks.  相似文献   
29.
Multiple mating by honeybee queens results in colonies of genotypically diverse workers. Recent studies have demonstrated that increased genetic diversity within a honeybee colony increases the variation in the frequency of tasks performed by workers. We show that genotypically diverse colonies, each composed of 20 subfamilies, collect more pollen than do genotypically similar colonies, each composed of a single subfamily. However, genotypically similar colonies collect greater varieties of pollen than do genotypically diverse colonies. Further, the composition of collected pollen types is less similar among genotypically similar colonies than among genotypically diverse colonies. The response threshold model predicts that genotypic subsets of workers vary in their response to task stimuli. Consistent with this model, our findings suggest that genotypically diverse colonies likely send out fewer numbers of foragers that independently search for pollen sources (scouts) in response to protein demand by the colony, resulting in a lower variety of collected pollen types. The cooperative foraging strategy of honeybees involves a limited number of scouts monitoring the environment that then guide the majority of foragers to high quality food sources. The genetic composition of the colony appears to play an important role in the efficiency of this behavior.  相似文献   
30.
This study analyses the impact of the Prestige oil spill on the mental health and the perception of physical health and functional capacity in the affected population. The sample comprised 926 residents from the section of the Spanish coast affected by the oil spill. The data was collected slightly more than one year after the accident. Scales referring to clinical symptoms (SCL‐36) and health‐related quality of life (SF‐36) were administered. The results suggest that individuals with higher degrees of exposure or residing in areas closest to the spill show lower levels of mental health in comparison to those with lower levels of exposure or living in areas farther away from the spill. This study also finds that women and fishermen tend to suffer more from the consequences of these types of disaster.  相似文献   
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