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排序方式: 共有248条查询结果,搜索用时 15 毫秒
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Simon R. Bacon M.Phil. Jesus J. Ojeda Ph.D. Rory Downham B.Sc. Vaughn G. Sears B.Sc. Benjamin J. Jones Ph.D. C.Phys. 《Journal of forensic sciences》2013,58(6):1486-1494
The effectiveness of latent fingerprint development techniques is heavily influenced by the physical and chemical properties of the deposition surface. The use of powder suspensions is increasing for development of prints on a range of surfaces. We demonstrate that carbon powder suspension development on polymers is detrimentally affected by the presence of common white pigment, titanium dioxide. Scanning electron microscopy demonstrates that patches of the compound are clearly associated with increased levels of powder adhesion. Substrates with nonlocalized titanium dioxide content also exhibit increased levels of carbon powder staining on a surface‐wide basis. Secondary ion mass spectrometry and complementary techniques demonstrate the importance of levels of the pigment within the top 30 nm. The association is independent of fingermark deposition and may be related to surface energy variation. The detrimental effect of the pigment is not observed with small‐particle reagent (MoS2 SPR) or cyanoacrylate (superglue) fuming techniques that exploit different development mechanisms. 相似文献
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Apparatus to produce a spatially and temporally uniform heat source is described and this is used to visualize latent fingerprints deposited onto thermal paper by raising the temperature of the paper. Results show an improvement over previous research when fingerprint deposits are aged or the developed fingerprints faint; visualization being enhanced by the use of a blue LED light source of 465 nm peak wavelength. An investigation of the components in fingerprint sweat likely to affect the solubility and hence color change of the dye present in the thermal paper has shown that polar protic solvents able to donate a proton are favored and a polar amino acid found commonly in eccrine fingerprint sweat (lysine) has been shown able to produce the desired color change. Aged fingerprint deposits on thermal paper from a variety of sources up to 4 years old have been visualized with this technique. 相似文献
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This article evaluates a hybrid seed contract between Indonesian smallholders and Pioneer Hybrid International. A transaction cost approach was used to analyse contract participation, total farm gross margins and labour and chemical use. The empirical results suggest: (a) the contract favours farmers with more irrigated land; (b) the contract improved returns to farm capital and was welfare improving; (c) the contract increased the demand for non-family labour, particularly female labour; and (d) the contract increased the intensity of chemical use. The success of the contract was attributed to the nature of the contracting process, which was between Pioneer and grower groups and not individual smallholders. 相似文献
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The changes in intergovernmental finance which occurred in the 1980s have impacted the traditional roles of state and local governments in many areas. The changing roles of such governments in the financing of infrastructure and public capital investments have been particularly pronounced. Their growing responsibilities in infrastructure finance has led to an enhanced emphasis on capital budgeting and on developing new initiatives in the capital financing arena. This article explores the impact of such changes on the strategies that are and will, probably, be employed by state and local governments to finance future capital acquisitions in a changing economy and intergovernmental fiscal environment. 相似文献
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Sansook Boonseub M.Sc. Greg Johnston Ph.D. Adrian Linacre D.Phil. 《Journal of forensic sciences》2012,57(6):1574-1577
Abstract: We report on the unambiguous identification of protected avian species from as little as one barb of a feather. Many avian species are protected by international agreements and national legislation, yet they are traded illegally because of their high value. Two sections of the avian mitochondrial genome were chosen to identify bird species, being a 561‐bp section of ND2 gene and a 921‐bp section of the ND5 gene. Two different DNA extraction methods were compared for their ability to reliably isolate sufficient DNA to be detected in a subsequent PCR. Using a commercial kit supplied by QIAGEN, a complete sequence was obtained from one barb for the ND2 gene, whereas two barbs were required to reliably sequence the 921‐bp section of the ND5 gene. The process worked on all species tested using feathers from archival museum specimens, resulted in minimal damage to the specimen and can readily be adopted by a forensic science laboratory. 相似文献
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