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11.
Fetal magnetic resonance (MR) imaging was performed at 33 weeks of gestation for investigation of a posterior fossa abnormality found at ultrasound screening. Fetal movements were abolished by vecuronium injected under ultrasound guidance into the umbilical vein. MR images showed atrophy of the left cerebellar lobe with cisternal dilatation. These were confirmed postnatally by CT scan.  相似文献   
12.
The Caribbean sponge, Plakortis simplex, is known to contain a large array of secondary metabolites, including the antimalarial polyketide plakortin, several unusual glycolipids, and some hopanoids, which closely resemble typical bacterial metabolites. The hypothesis that they could be products of bacterial metabolism was tested by localizing specific metabolites in cells using physical separation of sponge cells, bacterial symbionts and supernatant by differential centrifugation. The obtained fractions were analysed separately for the typical P. simplex metabolites by NMR and mass spectrometry, and most of them were shown to be present in the bacterial cells but not in the sponge cells. In addition, PCR screening showed that the biosynthetic pathway for glycosphingolipids was present in the bacterial cells. Isolation of a Sphingomonas strain PS193 from P. simplex and subsequent glycosphingolipid analysis resulted in the detection of a known glycosphingolipid, GSL-1, that did, however, not match the glycosphingolipid profile of P. simplex. Therefore, it is unlikely that Sphingomonas strain PS193 is an abundant member of the microbial community associated with P. simplex. Other glycosphingolipid producing bacteria in P. simplex remain to be identified. In conclusion, this study provides experimental evidence that the glycolipids and hopanoids and possibly also the polyketide plakortin are produced by microbial symbionts rather than the sponge from which the metabolites were originally isolated.  相似文献   
13.
Unsustainable hunting outside protected areas is threatening tropical biodiversity worldwide and requires conservationists to engage increasingly in antipoaching activities. Following the example of ecocertified logging companies, we argue that other extractive industries managing large concessions should engage in antipoaching activities as part of their environmental management plans. Onshore hydrocarbon concessions should also adopt antipoaching protocols as a standard because they represent a biodiversity threat comparable to logging. We examined the spatiotemporal patterns of small‐ and large‐mammal poaching in an onshore oil concession in Gabon, Central Africa, with a Bayesian occupancy model based on signs of poaching collected from 2010 to 2015 on antipoaching patrols. Patrol locations were initially determined based on local intelligence and past patrol successes (adaptive management) and subsequently with a systematic sampling of the concession. We generated maps of poaching probability in the concession and determined the temporal trends of this threat over 5 years. The spatiotemporal patterns of large‐ and small‐mammal poaching differed throughout the concession, and likely these groups will need different management strategies. By elucidating the relationship between site‐specific sampling effort and detection probability, the Bayesian method allowed us to set goals for future antipoaching patrols. Our results indicate that a combination of systematic sampling and adaptive management data is necessary to infer spatiotemporal patterns with the statistical method we used. On the basis of our case study, we recommend hydrocarbon companies interested in implementing efficient antipoaching activities in their onshore concessions to lay the foundation of long‐needed industry standards by: adequately measuring antipoaching effort; mixing adaptive management and balanced sampling; setting goals for antipoaching effort; pairing patrols with large‐mammal monitoring; supporting antipoaching patrols across the landscape; restricting access to their concessions; performing random searches for bushmeat and mammal products at points of entry; controlling urban and agricultural expansion; supporting bushmeat alternatives; and supporting land‐use planning.  相似文献   
14.
Connectivity in benthic marine animals with complex life cycles occurs primarily during the pelagic larval stage and depends deterministically on oceanographic dynamics. The scale of such larval dispersal is highly uncertain due the difficulty of direct measurement and poor knowledge of larval dynamics and ocean flow variability. This study characterizes the pattern of genetic connectivity in the ecosystem engineer Perumytilus purpuratus between latitudes 23°S and 33°S, which includes the ecological discontinuity reported for many taxa north to 32°S at the southeast Pacific. The genetic discontinuity observed in P. purpuratus around 26°S is described herein while that detected at 28°S is in line with the ecological discontinuity (in coverage, recruitment and density) previously reported for this mussel between 28°S and 32°S. Both discontinuities delimitate two major gene pools upon Bayesian inferences on geographical variation of five microsatellite loci. Interestingly, marker Pepu1 was responsible for most variation between pools and was potentially under selection. In fact, inferences excluding Pepu1 produced a single gene pool (k = 1) in central-northern Chile. The IBD connectivity pattern observed among P. purpuratus beds distributed in the interval 23°S–33°S is congruent with processes driven by larval dynamics, and the dominant equatorward Humboldt Current along a coast largely unaffected by ice during the last Pleistocene glaciation. However, the selective scenario unveiled by microsatellite Pepu1 inside the 25°S–28°S ecological discontinuity is consistent with selective processes associated with specific mesoscale properties operating in this area. This study highlights the usefulness of integrating different oceanographic scales, ecological data and population genetics to better understand connectivity of benthic marine species.  相似文献   
15.
Decades of intensive industrial and agricultural practices as well as rapid urbanization have left communities like Pueblo, Colorado facing potential health threats from pollution of its soils, air, water and food supply. To address such concerns about environmental contamination, we conducted an urban geochemical study of the city of Pueblo to offer insights into the potential chemical hazards in soil and inform priorities for future health studies and population interventions aimed at reducing exposures to inorganic substances. The current study characterizes the environmental landscape of Pueblo in terms of heavy metals, and relates this to population distributions. Soil was sampled within the city along transects and analyzed for arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb). We also profiled Pueblo’s communities in terms of their socioeconomic status and demographics. ArcGIS 9.0 was used to perform exploratory spatial data analysis and generate community profiles and prediction maps. The topsoil in Pueblo contains more As, Cd, Hg and Pb than national soil averages, although average Hg content in Pueblo was within reported baseline ranges. The highest levels of As concentrations ranged between 56.6 and 66.5 ppm. Lead concentrations exceeded 300 ppm in several of Pueblo’s residential communities. Elevated levels of lead are concentrated in low-income Hispanic and African-American communities. Areas of excessively high Cd concentration exist around Pueblo, including low income and minority communities, raising additional health and environmental justice concerns. Although the distribution patterns vary by element and may reflect both industrial and non-industrial sources, the study confirms that there is environmental contamination around Pueblo and underscores the need for a comprehensive public health approach to address environmental threats in urban communities.  相似文献   
16.
- DOI: http://dx.doi.org/10.1065/espr2006.01.009 Background, Aims and Scope Most existing models used to describe the fate of chemicals in surface water and sediment generally consider a 'static scenario', in which a contaminant is discharged at a constant rate and environmental input parameters do not change during the simulation time. This approach is not suitable in environmental scenarios characterized by daily or periodic changes of several input parameters. The aim of this study is to estimate approximate emissions of DDT lo Lake Maggiore using a new surface water model, (DynA Model) that describes the fate of a chemical in a dynamic scenario. Methods The model is developed on the grounds of an existing and validated model (QWASI). A numerical solution was adopted to build the fully dynamic version of the model. Results and Discussion The model was applied to Lake Maggiore emitting DDT at a constant rate until steady-state was reached. Emissions were stopped and later sporadic 'pulse' emissions were added. This was done to calculate the amount of DDT needed to simulate concentrations close to those measured in water and sediments. This allowed the evaluation of the order of magnitude of emissions. An uncertainty analysis for sediment resuspension was also performed, given the lack of measured resuspension rates. Conclusion The model showed the time response of the Lake Maggiore system to varying emission scenarios and provided what are regarded as reasonable estimates of DDT emissions. The model demonstrated the importance of sediment-water exchange. Recommendation and Outlook In order to better calculate DDT concentrations the model should be run with different discharge scenarios to clarify the time trends of concentrations, possibly with the use of different sets of measured data (such as biota and sediment deposition/resuspension rates).  相似文献   
17.
A multi-attribute analysis by means of the general multi-attribute analysis (GMAA) decision support system was performed in order to rank different strategies for good water quality with respect to trophic state, and good conditions for waterfowl, in the lagoon Ringkøbing Fjord, Denmark. The remedial strategies included nutrient abatement and the construction of facilities to increase the water exchange between the lagoon and the sea. The analysis showed that it is essential to keep the mean annual salinity level constant, since a drastic change in salinity may cause massive destruction of the macrophyte belt with large effects on the water quality and waterfowl abundance. It may be cost-effective to build and maintain a saltwater pumping station or a second sluice to increase the seawater inflow. Further nutrient abatement may not be cost-effective, at least not on time-scales shorter than 20 years, but the utility from nutrient abatement increases if a second sluice is built additionally. However, all of the remedial strategies, except decreasing the salinity, were projected to cause rather small changes in the effect variables compared to the no action alternative.  相似文献   
18.
Islands harbor a disproportionate amount of the earth's biodiversity, but a significant portion has been lost due in large part to the impacts of invasive mammals. Fortunately, invasive mammals can be routinely removed from islands, providing a powerful tool to prevent extinctions and restore ecosystems. Given that invasive mammals are still present on more than 80% of the world's major islands groups and remain a premier threat to the earth's biodiversity, it is important to disseminate replicable, scaleable models to eradicate invasive mammals from islands. We report on a successful model from western México during the past decade. A collaborative effort between nongovernmental organizations, academic biologists, Mexican government agencies, and local individuals has resulted in major restoration efforts in three island archipelagos. Forty-two populations of invasive mammals have been eradicated from 26 islands. For a cost of USD 21,615 per colony and USD 49,370 per taxon, 201 seabird colonies and 88 endemic terrestrial taxa have been protected, respectively. These conservation successes are a result of an operational model with three main components: i) a tri-national collaboration that integrates research, prioritization, financing, public education, policy work, capacity building, conservation action, monitoring, and evaluation; ii) proactive and dedicated natural resource management agencies; and iii) effective partnerships with academic researchers in Mexico and the United States. What is now needed is a detailed plan to eradicate invasive mammals from the remaining islands in the region that integrates the needed additional financing, capacity, technical advances, and policy issues. Island conservation in western Mexico provides an effective approach that can be readily applied to other archipelagos where conservation efforts have been limited.  相似文献   
19.
The aim of this work was to develop a method to assess the microbial accessibility of native phenanthrene present in soils and sediments. We developed an accelerated biodegradation assay, characterized by (a) inoculation with a sufficient number of phenanthrene-degrading microorganisms, (b) monitoring of the biodegradation activity through 14C-mineralization measurements, and (c) single-step chemical analysis of the native compound in the residue. The use of 14C-labeling allowed the determination of the time period needed for biodegradation of the bioaccessible fraction of the native chemical. The method was tested with environmental samples having a wide range of phenanthrene concentrations, i.e., from background levels (μg kg-1) originating in soil from atmospheric deposition, to acute concentrations (g kg-1) corresponding to industrial pollution of soils and sediments. The results showed a wide range of bioaccessibility (15–95% of the initial amount). The method can be used for the assessment of bioaccessibility involved in the management of polycyclic aromatic hydrocarbon (PAH) pollution.  相似文献   
20.
Many chelonians have colourful dots, patches and stripes throughout their body that are made up, at least in part, of carotenoids. Therefore, turtles are very suitable models to study the evolution and functionality of carotenoid-based colouration. Recent studies suggested a close link between colouration and immune system in these taxa. However, more research is needed to understand the role of these colourful stripes and patches in turtle visual signalling. The purpose of this study was to explore the relationship between growth rate and colouration in European pond turtles. In particular, we wanted to answer the question of whether there is a trade-off between growth and colour expression. We also aimed to explore the effect of body size and age on colour variation. Turtles from a reintroduction-breeding program were recaptured, weighed and measured over an 8-year period to estimate their growth rates and age. We also measured with a spectrometer the reflectance of colour patches in two different body parts: shell and forelimb. We found that turtles with a faster growth rate had brighter limb stripes independently of their age. On the other hand, shell colouration was related to body size with larger turtles having brighter shell stripes and higher values of carotenoid chroma. Our results suggest that fast-growers may afford to express intense colourful limb stripes likely due to their higher intake of carotenoids that would modulate both growth and colour expression. However, shell colouration was related to body size probably due to ontogenetic differences in the diet, as juveniles are strictly carnivorous while adults are omnivorous. Alternatively, shell colouration might be involved in crypsis as the shell is visually exposed to predators.  相似文献   
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