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A Review of the IAG GeoPT™ and Certification Programmes,their Protocols,and the Differences between the Original and Potential Modifications to the Certification Protocol 下载免费PDF全文
Jean S. Kane 《Geostandards and Geoanalytical Research》2015,39(4):419-432
The IAG conducts two programmes, the GeoPT ? proficiency test and a certification programme that are closely interconnected. Both support the quality control/quality assurance activities of geochemical laboratories. Each derives an estimate of ‘true value’ for a number of samples, but arrives at that estimate, and its uncertainty, differently. This review discusses the history of the two programmes and compares the ‘true values’ and their uncertainties obtained through each. It then considers ‘fitness‐for‐purpose’ issues related to both GeoPT ? and certification uncertainties. Issues related to potential modification of the IAG protocol for certification are also considered. 相似文献
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Protracted oogenesis and annual reproductive periodicity in the deep‐sea pennatulacean Halipteris finmarchica (Anthozoa,Octocorallia) 下载免费PDF全文
Halipteris finmarchica is one of the most common species of deep‐sea pennatulacean corals in the Northwest Atlantic; it was recently determined to act as a biogenic substrate for other species and as a nursery for fish larvae. Its reproductive cycle was investigated in colonies sampled in 2006 and 2007 along the continental slope of Newfoundland and Labrador (Canada). Halipteris finmarchica exhibits large oocytes (maximum diameter of 1000 μm), which are consistent with lecithotrophic larval development. Female potential fecundity based on mature oocytes just before spawning was ~6 oocytes · polyp?1 (500–6300 oocytes · colony?1); male potential fecundity was 16 spermatocysts · polyp?1 (5500–57,400 spermatocysts · colony?1). Based on statistical analysis of size‐probability frequency distributions, males harboured one cohort of spermatocysts that matured inside 8–11 months, whereas females harboured two distinct cohorts of oocytes; a persistent pool of small ones (≤400 μm) and a small number (~20%) of larger ones that grew from ~400 to >800 μm over a year. Despite this difference in the tempo of oogenesis and spermatogenesis, a synchronic annual spawning was detected. A latitudinal shift in the spawning period occurred from south (April in the Laurentian Channel) to north (May in Grand Banks and July–August in Labrador/Lower Arctic), following the development of the phytoplankton bloom (i.e. sinking of phytodetritus). Prolonged oogenesis with the simultaneous presence of different oocyte classes in a given polyp is likely not uncommon in deep‐sea octocorals and could hamper the detection of annual/seasonal reproduction when sample sizes are low and/or time series discontinued or brief. 相似文献
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Integrative taxonomic description of Plakina kanaky,a new polychromatic sponge species from New Caledonia (Porifera: Homoscleromorpha) 下载免费PDF全文
César Ruiz Julijana Ivanišević Pierre Chevaldonné Alexander V. Ereskovsky Nicole Boury‐Esnault Jean Vacelet Olivier P. Thomas Thierry Pérez 《Marine Ecology》2015,36(4):1129-1143
Four similar sponges of different colors, all unknown to science, were collected in submarine caves of New Caledonia. We aimed at determining whether the four chromotypes represented different species or phenotypic variations of a unique new species. We used an integrative taxonomic approach combining morphologic, molecular and metabolomic analyses. The main traits that define these specimens are a skeleton made of monolophose, trilophose and tetralophose calthrops only, high chemical diversity and a high abundance and diversity of prokaryotic symbionts. The symbiotic community includes two unique prokaryote morphotypes, which are described for the first time in Homoscleromorpha, and appeared to be vertically transmitted. Although several features slightly differ among chromotypes, the most parsimonious conclusion was to propose a single new species Plakina kanaky sp. nov. Our phylogenetic analysis indicated the paraphyly of the Plakina genus, with P. kanaky sp. nov. belonging to a clade that includes Plakina jani and Plakina trilopha. The present work demonstrates that integrative taxonomy should be used in order to revise the entire Plakinidae family and especially the non‐monophyletic genus Plakina. 相似文献
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Geoffrey Caruso Gilles Vuidel Jean Cavailhès Pierre Frankhauser Dominique Peeters Isabelle Thomas 《Journal of Geographical Systems》2011,13(1):31-48
We present a model that simulates the growth of a metropolitan area on a 2D lattice. The model is dynamic and based on microeconomics.
Households show preferences for nearby open spaces and neighbourhood density. They compete on the land market. They travel
along a road network to access the CBD. A planner ensures the connectedness and maintenance of the road network. The spatial
pattern of houses, green spaces and road network self-organises, emerging from agents individualistic decisions. We perform
several simulations and vary residential preferences. Our results show morphologies and transition phases that are similar
to Dieletric Breakdown Models (DBM). Such similarities were observed earlier by other authors, but we show here that it can be deducted from the functioning
of the land market and thus explicitly connected to urban economic theory. 相似文献
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Jean‐Paul van Gestel Kevin D. Best Olav I. Barkved Jan H. Kommedal 《Geophysical Prospecting》2011,59(4):673-681
The frequent time‐lapse observations from the life of field seismic system across the Valhall field provide a wealth of information. The responses from the production and injection wells can be observed through time‐shift and amplitude changes. These observations can be compared to modelled synthetic seismic responses from a reservoir simulation model of the Valhall Field. The observed differences between the observations and the modelling are used to update and improve the history match of the reservoir model. The uncertainty of the resulting model is reduced and a more confident prediction of future reservoir performance is provided. A workflow is presented to convert the reservoir model to a synthetic seismic response and compare the results to the observed time‐lapse responses for any time range and area of interest. Correlation based match quality factors are calculated to quantify the visual differences. This match quality factor allows us to quantitatively compare alternative reservoir models to help identify the parameters that best match the seismic observations. Three different case studies are shown where this workflow has helped to reduce the uncertainty range associated with specific reservoir parameters. By updating various reservoir model parameters we have been able to improve the match to the observations and thereby improve the overall reservoir model predictability. The examples show positive results in a range of different reservoir modelling issues, which indicates the flexibility of this workflow and the ability to have an impact in most reservoir modelling challenges. 相似文献
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Progress in some areas of process‐based aeolian sediment transport research is hampered by limited opportunities for data comparison, synthesis, and integration. This is partially due to a lack of reliable comparison methods. Many comparison methods are forms of calibration that are either restrictive (e.g., time‐averages only) or non‐existent (e.g., for field‐based sediment transport thresholds or vertical mass flux profiles). It is believed that the adoption of standard methods for common measurements may improve inter‐study comparison, add value and longevity to data, and advance integrative modeling efforts. Examples of approaches in allied disciplines where standards are used routinely are reviewed and we discuss how the mutual benefits of standardized data could outweigh perceived disadvantages. Overall, the goal of this commentary is to encourage discussion, self‐assessment, and forethought with regard to measurement methods used in process‐based aeolian geomorphology. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献