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71.
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73.
Dr Helen M. Kingston Consultant Clinical Geneticist Umberto Nicolini John Haslam Tony Andrews 《黑龙江环境通报》1993,13(7):637-642
46,XY/47,XY, + 17p + mosaicism was found in two primary amniotic fluid cultures (AFCs). Fetal blood karyotype was normal, but ultrasonography revealed Dandy-Walker malformation and bilateral choroid plexus cysts. Following termination of pregnancy, fetal examination revealed post-axial polydactyly and neuroblastoma-in-situ affecting both adrenals in addition to the cerebellar abnormalities. Mosaicism for the aberrant cell line was confirmed in all fetal tissues sampled and in the placenta. 相似文献
74.
Marion Petrie Marion Hall Tim Halliday Helen Budgey Chris Pierpoint 《Behavioral ecology and sociobiology》1992,31(5):349-358
Summary Approximately 50% of marked peahens (Pavo cristatus) mate more than once with lek males. Some females mate with more than one male, others copulate repeatedly with the same male. The frequency of courtship also shows marked variation. Some females repeatedly engage males in courtship interactions after they have succesfully copulated with them. The likelihood of mating with more than one male increases if a female first mates with a non-preferred (unsuccessful male). There is a non-significant tendency for females to copulate with a more successful male when remating. Peahens may mate with a non-preferred male first if they do not encounter a successful male during their initial period of choice, perhaps because the most successful male on a lek was courting another female and/or was defended by another female. There are more aggressive interactions between females in front of preferred males. Preferred males receive more repetitive courtship behaviour and repeated matings. Dominant females are more likely to engage in repetitive courtship and matings. The number of times a female initiates courtship on any one day increases with the number of other females actively courting males at a lek site on that day. We suggest that there is competition amongst females for access to preferred males and that dominant females try to monopolise these males by repeatedly engaging them in courtship interactions. We discuss the implications of these observations for the idea that female may gain directly from mate choice in a species where males contribute nothing but gametes to their offspring.
Correspondence to: M. Petrie at the present address 相似文献
75.
Graeme J Inglis Helen Hurren John Oldman Rachel Haskew 《Ecological applications》2006,16(4):1377-1390
Eradication and control of invasive species are often possible only if populations are detected when they are small and localized. To be efficient, detection surveys should be targeted at locations where there is the greatest risk of incursions. We examine the utility of habitat suitability index (HSI) and particle dispersion models for targeting sampling for marine pests. Habitat suitability index models are a simple way to identify suitable habitat when species distribution data are lacking. We compared the performance of HSI models with statistical models derived from independent data from New Zealand on the distribution of two nonindigenous bivalves: Theora lubrica and Musculista senhousia. Logistic regression models developed using the HSI scores as predictors of the presence/absence of Theora and Musculista explained 26.7% and 6.2% of the deviance in the data, respectively. Odds ratios for the HSI scores were greater than unity, indicating that they were genuine predictors of the presence/ absence of each species. The fit and predictive accuracy of each logistic model were improved when simulated patterns of dispersion from the nearest port were added as a predictor variable. Nevertheless, the combined model explained, at best, 46.5% of the deviance in the distribution of Theora and correctly predicted 56% of true presences and 50% of all cases. Omission errors were between 6% and 16%. Although statistical distribution models built directly from environmental predictors always outperformed the equivalent HSI models, the gain in model fit and accuracy was modest. High residual deviance in both types of model suggests that the distributions realized by Theora and Musculista in the field data were influenced by factors not explicitly modeled as explanatory variables and by error in the environmental data used to project suitable habitat for the species. Our results highlight the difficulty of accurately predicting the distribution of invasive marine species that exhibit low habitat occupancy and patchy distributions in time and space. Although the HSI and statistical models had utility as predictors of the likely distribution of nonindigenous marine species, the level of spatial accuracy achieved with them may be well below expectations for sensitive surveillance programs. 相似文献
76.
Analysis of shoreline change is often based exclusively upon the littoral cell concept and modelling of hydrodynamic processes.
The Futurecoast study has considered fresh approaches to assessing shoreline evolution, which have been used to provide an
analysis of future long-term evolution for the entire shoreline of England and Wales. This has been based upon an improved
understanding of coastal systems and their behavioural characteristics. The study has included a range of supporting studies,
focussing upon maximizing use of existing information and experience. A number of additional data sets have also been produced.
The integration of leading expertise from different areas of coastal research to collectively consider this information has
been the foundation for the study. The key outputs from this research are: (1) Improved understanding of coastal behaviour;
(2) Assessment of future shoreline evolution; (3) Supporting information and data; (4) Delivery of results on an interactive
CD-ROM. 相似文献
77.
78.
Helen M. Boylan Randy D. Cain H.M. “Skip” Kingston 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1318-1325
Abstract U.S. Environmental Protection Agency (EPA) Method 7473 for the analysis of mercury (Hg) by thermal decomposition, amalgamation, and atomic absorption spectroscopy has proved successful for use in Hg assessment at coal-fired power stations. In an analysis time of ~5 min per sample, this instrumental methodology can directly analyze total Hg—with no discrete sample preparation—in the solid matrices associated with a coal-fired power plant, including coal, fly ash, bottom ash, and flue gas desulfurization (FGD) material. This analysis technique was used to investigate Hg capture by coal combustion byproducts (CCBs) in three different coal-fired power plant configurations. Hg capture and associated emissions were estimated by partial mass balance. The station equipped with an FGD system demonstrated 68% capture on FGD material and an emissions estimate of 18% (11 kg/yr) of total Hg input. The power plant equipped with low oxides of nitrogen burners and an electrostatic precipitator (ESP) retained 43% on the fly ash and emitted 57% (51 kg/yr). The station equipped with conventional burners and an ESP retained less than 1% on the fly ash, emitting an estimated 99% (88 kg/yr) of Hg. Estimated Hg emissions demonstrate good agreement with EPA data for the power stations investigated. 相似文献
79.
Kang CM Koutrakis P Suh HH 《Journal of the Air & Waste Management Association (1995)》2010,60(11):1327-1334
Hourly concentrations of ambient fine particle sulfate and carbonaceous aerosols (elemental carbon [EC], organic carbon [OC], and black carbon [BC]) were measured at the Harvard-U.S. Environmental Protection Agency Supersite in Boston, MA, between January 2007 and October 2008. These hourly concentrations were compared with those made using integrated filter-based measurements over 6-day or 24-hr periods. For sulfate, the two measurement methods showed good agreement. Semicontinuous measurements of EC and OC also agreed (but not as well as for sulfate) with those obtained using 24-hr integrated filter-based and optical BC reference methods. During the study period, 24-hr PM2.5 (particulate matter [PM] < or = 2.5 microm in aerodynamic diameter) concentrations ranged from 1.4 to 37.6 microg/m3, with an average of 9.3 microg/m3. Sulfate as the equivalent of ammonium sulfate accounted for 39.1% of the PM2.5 mass, whereas EC and OC accounted for 4.2 and 35.2%, respectively. Hourly sulfate concentrations showed no distinct diurnal pattern, whereas hourly EC and BC concentrations peaked during the morning rush hour between 7:00 and 9:00 a.m. OC concentrations also exhibited nonpronounced, small peaks during the day, most likely related to traffic, secondary organic aerosol, and local sources, respectively. 相似文献
80.
James J. Keenan Helen Vega Robert I. Krieger 《Journal of environmental science and health. Part. B》2013,48(6):538-545
The magnitude and distribution of cypermethrin from total release, over-the-counter foggers was studied in a test room and in residences to facilitate evaluation of regulatory exposure algorithms and new human exposure assessments based upon urine biomonitoring. Surface residue (SR) was evenly distributed in a small test room (3.6 μ g cypermethrin/cm2) where thorough mixing of the aerosol occurred. In a residence SR was significantly affected by room size and distance from the fogger. Air levels in the residence were as high as 30 μ g cypermethrin/cm3 after 4.5 h. The availability of surface residues was measured with an automated surface cotton cloth wipe and ethyl acetate extraction. Only 5% of the SR was available from nylon carpet. Tile, wood and linoleum resulted in 30, 10, and 10% of SR being available, respectively. These data are used to estimate cypermethrin exposure of children and adults for comparison with existing regulatory reference dosages and exposure assessments based upon biomonitoring. 相似文献