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591.
A 6-month field intercomparison study on precipitation measurements was performed at Schagerbrug near the west coast in the Netherlands. Twenty bulk sampling systems and two wet-only samplers were evaluated on accuracy, sampling strategy and performance under field conditions. Bulk precipitation fluxes of NO3-, NH4+, H+ and Kjeldahl-N generally could be determined with a greater accuracy than bulk precipitation fluxes of SO4(2-), Na+, Cl-, Mg2+, Ca2+, Alkalinity and H+. Bulk precipitation fluxes of K+ generally had the lowest accuracy. Only 20% of the sampling systems differed less than 10% from the best estimate, whereas most systems (60%) differed more than 20% from the best estimate. The inaccuracy induced by the sampling system appeared to be much larger than that resulting from the analysis of the samples by different laboratories as determined by ring-tests.  相似文献   
592.
The European Raja clavata and the South African R. straeleni are marine skates which exhibit highly conserved morphological and ecological traits. Owing to this, taxonomic and evolutionary relationships between the two taxa have not yet fully elucidated. Here, we have tested the hypothesis that restricted gene flow and genetic divergence between these taxa might be associated with climatic/oceanographic discontinuities by surveying genetic variation in ten geographical samples at control region (CR) and amplified fragment length polymorphism (AFLP) loci. The clustering of CR haplotypes in two reciprocally monophyletic clades consistent with taxon zoogeography and the significant AFLP F values between the European and South African populations indicated the two taxa as recently diverged peripatric sibling species. Within each species, significant spatial genetic heterogeneity among samples at both markers revealed population structuring. We argued that structured populations and isolated sibling species might represent two stages of geographical speciation.  相似文献   
593.
Polygyny and extra-pair paternity are generally thought to enhance sexual selection. However, the extent to which these phenomena increase variance in male reproductive success will depend on the covariance between success at these two strategies. We analysed these patterns over four breeding seasons in facultatively polygynous blue tits Cyanistes caeruleus. We found that both polygyny and extra-pair paternity increased variance in male reproductive success and that standardised variance in annual number of genetic fledglings was 2.6 times higher than standardised variance in apparent success when assuming strict monogamy. Nevertheless, male success at securing within-pair paternity was unrelated to success at gaining extra-pair paternity and, when considering the positive effect of age on extra-pair success and attracting a second female, polygynous males were no more likely to sire extra-pair fledglings. Overall, polygynous males fledged more genetic offspring than monogamous males, but first-year polygynous males lost a greater share of within-pair paternity. A literature review suggests that this adverse effect of polygyny on within-pair paternity is frequent among birds, inconsistent with the prediction that females engage in extra-pair copulation with successful males to obtain good genes. Furthermore, a male's share of paternity was repeatable between years, and among females of polygynous males within years, such that a compatibility function of extra-pair copulations was likewise unsupported. Instead, we suggest that the observed patterns are most consistent with a fertility insurance role for extra-pair copulations, which does not exclude the greater opportunity for sexual selection through differential ability of males to gain paternity.  相似文献   
594.
We present examples of cumulative chemical risk mapping methods developed within the NoMiracle project. The different examples illustrate the application of the concentration addition (CA) approach to pesticides at different scale, the integration in space of cumulative risks to individual organisms under the CA assumption, and two techniques to (1) integrate risks using data-driven, parametric statistical methods, and (2) cluster together areas with similar occurrence of different risk factors, respectively. The examples are used to discuss some general issues, particularly on the conventional nature of cumulative risk maps, and may provide some suggestions for the practice of cumulative risk mapping.  相似文献   
595.
Several soil microorganisms colonizing roots are known to naturally promote the health of plants by controlling a range of plant pathogens, including bacteria, fungi, and nematodes. The use of theses antagonistic microorganisms, recently named plant-probiotics, to control plant-pathogenic fungi is receiving increasing attention, as they may represent a sustainable alternative to chemical pesticides. Many years of research on plant-probiotic microorganisms (PPM) have indicated that fluorescent pseudomonads producing antimicrobial compounds are largely involved in the suppression of the most widespread soilborne pathogens. Phenotype and genotype analysis of plant-probiotic fluorescent pseudomonads (PFP) have shown considerable genetic variation among these types of strains. Such variability plays an important role in the rhizosphere competence and the biocontrol ability of PFP strains. Understanding the mechanisms by which genotypic and phenotypic diversity occurs in natural populations of PFP could be exploited to choose those agricultural practices which best exploit the indigenous PFP populations, or to isolate new plant-probiotic strains for using them as inoculants. A number of different methods have been used to study diversity within PFP populations. Because different resolutions of the existing microbial diversity can be revealed depending on the approach used, this review first describes the most important methods used for the assessment of fluorescent Pseudomonas diversity. Then, we focus on recent data relating how differences in genotypic and phenotypic diversity within PFP communities can be attributed to geographic location, climate, soil type, soil management regime, and interactions with other soil microorganisms and host plants. It becomes evident that plant-related parameters exert the strongest influence on the genotypic and phenotypic variations in PFP populations.  相似文献   
596.
Environmental Fluid Mechanics - Linear stability analysis is used to investigate the behavior of small perturbations of a uniform flow in a straight channel with an erodible bed composed by a...  相似文献   
597.
Environmental Science and Pollution Research - The surface coating present on a marble Piety dating to the Renaissance period and stored at the Castello Sforzesco-Museum of Ancient Art (Milan,...  相似文献   
598.
Environmental Science and Pollution Research - Cyclodextrin nanosponges (CD-NS) are cross-linked cyclodextrin polymers characterized by a nanostructured three-dimensional network. CD-NSs in the...  相似文献   
599.
Journal of Material Cycles and Waste Management - In this work, the synthesis of biochar from several biomass wastes to act as matrix for urea was investigated. The objective was to select the most...  相似文献   
600.

Objective

To evaluate fetal brain development using MRI (magnetic resonance imaging) in CDH (congenital diaphragmatic hernia).

Methods

52 isolated left CDH and 104 control fetuses were imaged using MRI. Brain morphometry (Biparietal diameter—BPD, brain fronto-occipital diameter—BFOD, third ventricle, posterior ventricles, transcerebellar diameter—TCD, anteroposterior and craniocaudal cerebellar vermis diameter—AP and CC) and cortical structures (bilateral cingulate fissure—CF, insular fissure—IF, insular depth - ID) were compared with controls using Mann–Whitney test.

Results

Median gestational age at MRI (p = 0.95)and the median biparietal diameter (p = 0.737) were comparable. Among morphometric parameters, only the brain fronto-occipital diameter was significantly smaller in CDH (p = 0.001) and the third ventricle was significantly greater in CDH (<0.0001). Among cortical structures, the cingulate and insular fissures were significantly deeper in CDH fetuses (p < 0.0001) as the insular depth ID was smaller in CDH (p < 0.03).

Conclusions

CDH fetuses have a smaller fronto-occipital diameter, reduced insular depth, deeper cingulate and insular fissure, and greater third ventricle width as compared to controls. These findings suggest that left CDH may have an impact on fetal brain development with an overall reduction in brain volume.  相似文献   
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