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The aim of the present study was to assess the sonographic contour of the increased nuchal translucency (NT) and to correlate this with pregnancy outcome. Fifty sonographic images of fetuses with increased NT [>95th centile thickness of the normal range for crown–rump length (CRL) between 38 and 84 mm] were retrospectively assessed. In all the cases a complete pregnancy and even infancy follow-up (<36 months) was available. The NT appearances were subdivided into two forms: a ‘notched’ or ‘uniform’ appearance. The images were correlated with karyotype results [trisomy 21 (DS) vs euploid cases] and pregnancy outcome. Complicated outcomes were classified as being either DS fetuses, miscarriage or termination of pregnancy because of structural anomaly. Thus 30/35 (86%) of the euploid fetuses had a ‘uniformly’ increased NT, whereas 8/13 DS cases (62%) had a ‘notched’ appearance (Fisher's exact test, p=0.004). Additionally, 27/29 fetuses (93%) which had an uneventful pregnancy outcome had a ‘uniform’ increased NT, whereas 12/26 (57%) of the fetuses which had adverse pregnancy outcome had a ‘notched’ appearance of their NT (Fisher's exact test, p<0.001). Although it was not possible to correlate the sonographic data with post-evacuation microdissection findings, it is possible that a uniformly shaped, increased NT may be more representative of a developmental delay in a normal fetus. Conversely, a ‘notched’ nuchal surface may represent abnormal lymphatic or cardiovascular development more commonly seen in DS fetuses. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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Fungal activity is thought to play a direct and effective role in the breakdown and dissolution of primary minerals and in the synthesis of clay minerals in soil environments, with important consequences for plant growth and ecosystem functioning. We have studied primary mineral weathering in volcanic soils developed on trachydacite in southern Tuscany using a combination of qualitative and quantitative mineralogical and microbiological techniques. Specifically, we characterized the weathering and microbiological colonization of the magnetically separated ferromagnesian minerals (biotite and orthopyroxene) and non-ferromagnesian constituents (K-feldspar and volcanic glass) of the coarse sand fraction (250-1,000 microm). Our results show that in the basal horizons of the soils, the ferromagnesian minerals are much more intensively colonized by microorganisms than K-feldspar and glass, but that the composition of the microbial communities living on the two mineral fractions is similar. Moreover, X-ray diffraction, optical and scanning electron microscope observations show that although the ferromagnesian minerals are preferentially associated with an embryonic form of the clay mineral halloysite, they are still relatively fresh. We interpret our results as indicating that in this instance microbial activity, and particularly fungal activity, has not been an effective agent of mineral weathering, that the association with clay minerals is indirect, and that fungal weathering of primary minerals may not be as important a source of plant nutrients as previously claimed. 相似文献
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Ian?H.?RowlandsEmail author 《Mitigation and Adaptation Strategies for Global Change》2011,16(7):749-773
This article analyses the debate associated with the ancillary impacts of climate change mitigation options in developing
countries, with a particular focus upon Africa’s 34 least developed countries. While these countries’ emissions of greenhouse
gases are relatively small (and they do not have emission limitation commitments in the current international regime), inattention
to the mitigation agenda would mean that developing countries both miss potential funding opportunities and fail to ‘climate-proof’
their development strategies. A focus, therefore, upon the short-term, local, developmental impacts that serve to change the
relative attractiveness of different mitigation options from the perspective of the developing country is in these countries’
current strategic interests. In this article, I examine three energy-related climate change mitigation options: improved cookstoves,
carbon-free electricity and improved energy efficiency in industry. Key ancillary impacts are better indoor air quality, better
outdoor air quality and job creation (respectively). Further work to strengthen the evidence base regarding these impacts
needs to be undertaken, potentially drawing upon broader work that has already been completed. Thus, in conclusion, a call
for cross-fertilisation of information between heretofore disparate research communities is made. Additionally, the development
of an integrated research agenda, forging linkages among cookstoves, indoor air quality and climate change mitigation research
communities in Africa’s least developed countries, is identified as a priority. 相似文献
248.
Ian C. Hewitt Alexander G. Fernald Zohrab A. Samani 《Journal of the American Water Resources Association》2018,54(4):962-973
Currently, there is no agreed upon method for estimating evapotranspiration (ET) across large regions such as the state of New Mexico. Remote sensing methods have potential for providing a solution, but require validation. A comparison between field‐scale ET measurements using a portable chamber ET measurement device and modeled ET using the remote sensing Regional Evapotranspiration Estimation Model (REEM) was performed where the model had not been previously evaluated. Data were collected during the growing season of 2015 in three irrigated agricultural valleys of northern New Mexico in agricultural and nonagricultural settings. No statistically significant difference was observed in agricultural datasets between means of measured (M = 3.7 mm/day, SE = 0.31 mm/day) and modeled (M = 4.0 mm/day, SE = 0.01 mm/day) daily ET; t(17) = ?1.50, p = 0.15, α = 0.05. As there was no statistical difference observed between agricultural datasets, results support the use of REEM in irrigated agricultural areas of northern New Mexico. A statistically significant difference was observed in nonagricultural datasets between means of measured (M = 1.7 mm/day, SE = 0.22 mm/day) and modeled (M = 0.0 mm/day, SE = 0.00 mm/day) daily ET; t(9) = 1.79, p = 5.7 × 10?6, α = 0.05. With additional calibrations and air temperature sensors placed outside of agricultural areas, REEM may be suitable for use in nonagricultural areas of northern New Mexico. 相似文献
249.
Emma R. Wilson Kelly L. Smalling Timothy J. Reilly Elmer Gray Laura Bond Lance Steele Prasanna Kandel Alison Chamberlin Justin Gause Nicole Reynolds Ian Robertson Stephen Novak Kevin Feris Merlin M. White 《Journal of the American Water Resources Association》2014,50(2):420-433
Fungicides are moderately hydrophobic and have been detected in water and sediment, particularly in agricultural watersheds, but typically are not included in routine water quality monitoring efforts. This is despite their widespread use and frequent application to combat fungal pathogens. Although the efficacy of these compounds on fungal pathogens is well documented, little is known about their effects on nontarget fungi. This pilot study, a field survey in southwestern Idaho from April to December 2010 on four streams with varying pesticide inputs (two agricultural and two reference sites), was conducted to assess nontarget impact of fungicides on gut fungi, or trichomycetes. Tissues of larval black flies (Diptera: Simuliidae), hosts of gut fungi, were analyzed for pesticide accumulation. Fungicides were detected in hosts from streams within agricultural watersheds but were not detected in hosts from reference streams. Gut fungi from agricultural sites exhibited decreased percent infestation, density and sporulation within the gut, and black fly tissues had elevated pesticide concentrations. Differences observed between the sites demonstrate a potential effect on this symbiotic system. Future research is needed to parse out the details of the complex biotic and abiotic relationships; however, these preliminary results indicate that impacts to nontarget organisms could have far‐reaching consequences within aquatic ecosystems. 相似文献
250.
Kristen M. Hart Autumn R. Sartain Zandy-Marie Hillis-Starr Brendalee Phillips Philippe A. Mayor Kimberly Roberson Roy A. Pemberton Jr. Jason B. Allen Ian Lundgren Susanna Musick 《Marine Biology》2013,160(10):2567-2580
Surveys of juvenile hawksbills around Buck Island Reef National Monument, US Virgin Islands from 1994 to 1999 revealed distributional patterns and resulted in a total of 75 individual hawksbill captures from all years; turtles ranged from 23.2 to 77.7 cm curved carapace length (CCL; mean 42.1 ± 12.3 cm SD). Juveniles concentrated where Zoanthid cover was highest. Length of time between recaptures, or presumed minimum site residency, ranged from 59 to 1,396 days (mean 620.8 ± 402.4 days SD). Growth rates for 23 juveniles ranged from 0.0 to 9.5 cm year?1 (mean 4.1 ± 2.4 cm year?1SD). Annual mean growth rates were non-monotonic, with the largest mean growth rate occurring in the 30–39 cm CCL size class. Gastric lavages indicated that Zoanthids were the primary food source for hawksbills. These results contribute to our understanding of juvenile hawksbill ecology and serve as a baseline for future studies or inventories of hawksbills in the Caribbean. 相似文献