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161.
Nile crocodiles undergo a three to five order of magnitude increase in body size during their lifespan. This shift coincides with a change in resource and habitat use which influences the strength, type and symmetry of interactions with other species. Identifying size-specific crocodile groups displaying similar traits is important for conservation planning. Here, we illustrate how stable carbon (δ(13) C) and nitrogen (δ(15) N) isotope analysis of scute keratin, together with breakpoint modelling analysis can be used to characterise ontogenetic niche shifts. Using a sample set of 238 crocodiles from the Okavango Delta, Botswana (35-463?cm total length), we found prominent size-related changes in the scute keratin δ(13) C and δ(15) N profiles close to 40 and 119?cm snout-vent length. The first shift corroborated the findings of a traditional stomach-content study conducted on the same population at the same time, and the second conformed to known crocodile ecology. This approach can be used as a first approximation to identify size-specific groups within crocodile populations, and these can then be investigated further using isotopic or other methods. 相似文献
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163.
Frans J.C. Martins 《Tetrahedron》2009,65(15):2921-2926
Treatment of hexacyclo[7.4.2.01,9.03,7.04,14.06,15]pentadecane-10,12-diene-2,8-dione with aqueous sodium cyanide produced 2,8-dihydroxy-hexacyclo[7.4.2.01,9.03,7.04,14.06,15]pentadecane-10,12-diene-2,8-lactam and with sodium cyanide, ammonium chloride and ammonium hydroxide, 2-amino-8-hydroxy-hexacyclo [7.4.2.01,9.03,7.04,14.06,15]pentadecane-10,12-diene-2,8-lactam was obtained. 10-Hydroxy-hexacyclo [10.2.1.02,11.04,10.04,14.09,13]pentadecane-5,7-diene-3-one was converted into the corresponding aminonitrile and hexacyclo[10.2.1.02,11.04,10.04,14.09,13]pentadecane-5,7-diene-10-hydroxy-3-spiro-5′-hydantoin. Treatment of the latter with barium hydroxide produced exo-3-amino-10-hydroxy-hexacyclo [10.2.1.02,11.04,10.04,14.09,13]pentadecane-5,7-diene-endo-3-carboxylic acid. The isomeric endo-3-amino-10-hydroxy-hexacyclo[10.2.1.02,11.04,10.04,14.09,13]pentadecane-5,7-diene-exo-3-carboxylic acid was obtained from 3-cyano-3-ureido-hexacyclo[10.2.1.02,11.04,10.04,14.09,13]pentadecane-5,7-diene-10-ol. 相似文献
164.
Dirk C. de Graaf Wolfgang Ritter Frans J. Jacobs Marleen Brunain Hein Imberechts Koen Mintiens Yves Van der Stede Bart Verheyden Aud Kari Fauske Patrick Boujon Gabriela Chioveanu Daniel Dezmirean Giovanni Formato Franco Mutinelli Hendrik-Jan Roest Dalibor Titĕra Stephen F. Pernal Katia Knapen 《Accreditation and quality assurance》2009,14(5):273-276
We report on the first proficiency test in the context of honey bee disease testing on a broad international scale. Honey
samples were distributed to 12 participating laboratories for isolation and identification of spores of the etiological agent
of American foulbrood, Paenibacillus larvae. Of the 11 laboratories responding to this proficiency testing event, only 6 (54%) provided data that were in full agreement
with the previously determined status of the honey samples; eight (72%) laboratories fell within the threshold for qualification
as defined a priori in this proficiency test (=level of agreement of at least 90%). Some lessons can now be drawn from the
organizational point of view and will certainly improve new initiatives to be taken. 相似文献
165.
Frans B. Waanders Antoinne F. Mulaba-Bafubiandi Lonzeche Lodya 《Hyperfine Interactions》2014,226(1-3):721-735
South Africa is a country that is very rich in mineral resources but the use of Mössbauer spectroscopy to solve operational industrial problems is however very limited. In the Bushveld Igneous Complex the main minerals extracted from the ore are the platinum group metals and chromium, but secondary recovery of base metals such as nickel, copper and cobalt forms an integral part of the process. Losses of nickel in the slag can amount to about 4 % and subsequent a slag cleaning furnace is used to reduce the loss to less than 0.5 % nickel oxide. The Fe2+/Fe3+ ratio and mineralogy was used to determine the partial oxygen pressure in the furnaces and also the efficiency of the nickel recovery. From the Mössbauer results, augmented with XRD, SEM, EMP-WDX and MLA analyses, optimum conditions were determined to ensure minimum metal losses. The use of Mössbauer spectroscopy in the coal industry, to investigate mineral changes that occur during its use, is also of importance. The main minerals present in coal were determined with the aid of various techniques, such as Mössbauer, XRD, SEM and HR-TEM, with the major iron minerals found to be pyrite, illite, ankerite and jarosite. A large quantity of coal is used to produce syngas via gasification plants for the production of synthetic fuels. The change of the mineral matter during gasification was studied and the changes occurring during the gasification process were followed. The syngas produced, is further treated by means of the Fischer–Tropsch process where an iron catalyst is incorporated in the process. The usefulness and fouling of the catalyst is being studied with the aid of Mössbauer spectroscopy. The calibration of equipment to determine work hardening in mining equipment was also investigated and found to be a useful tool in industry. From the above few examples it is evident that, although used on a limited base, Mössbauer spectroscopy, augmented by various other spectroscopic tools, still ensures optimal recovery and production of the vast resource base of South Africa. 相似文献
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169.
Summary The reactions of D2 with OsHCl(CO)(PCy3)2 and the deuteriation reaction with C2H5OD have been studied. The deuteriation ratios in the PCy3 ligand have been calculated. The reaction mechanism for the deuteriation in C2H5OD is discussed. 相似文献
170.
Frans Lemeire 《Aequationes Mathematicae》1989,38(1):111-112
Problems and solutions 相似文献