The electrostatic process for imaging indentations on documents using the ESDA device is investigated under controlled experimental settings. An in-house modified commercial xerographic developer housing is used to control the uniformity and volume of toner deposition, allowing for reproducible image development. Along with this novel development tool, an electrostatic voltmeter and fixed environmental conditions facilitate an optimization process. Sample documents are preconditioned in a humidity cabinet with microprocessor control, and the significant benefit of humidification above 70% RH on image quality is verified. Improving on the subjective methods of previous studies, image quality analysis is carried out in an objective and reproducible manner using the PIAS-II. For the seven commercial paper types tested, the optimum ESDA operating point is found to be at an electric potential near -400V at the Mylar surface; however, for most paper types, the optimum operating regime is found to be quite broad, spanning relatively small electric potentials between -200 and -550V. At -400V, the film right above an indented area generally carries a voltage which is 30-50V less negative than the non-indented background. In contrast with Seward's findings [G.H. Seward, Model for electrostatic imaging of forensic evidence via discharge through Mylar-paper path, J. Appl. Phys. 83 (3) (1998) 1450-1456; G.H. Seward, Practical implications of the charge transport model for electrostatic detection apparatus (ESDA), J. Forensic Sci. 44 (4) (1999) 832-836], a period of charge decay before image development is not required when operating in this optimal regime. A brief investigation of the role played by paper-to-paper friction during the indentation process is conducted using our optimized development method. 相似文献
Inks from seven black and eight blue ballpoint pens were separated by a high-performance liquid chromatography (HPLC) method utilizing a photodiode array detection (PDA). A classifier flowchart was designed for the chromatographic data based on the presence or absence of certain peaks at different wavelengths to qualitatively discriminate between the inks. The same data were quantitatively classified by principal components analysis (PCA) to estimate the separation between a pair of classes of ink samples. It was found that the black ballpoint pen inks were discriminated satisfactorily utilizing two-dimensional data of the peak areas and retention times at the optimum wavelengths. The blue pens were discriminated by analyzing the chromatographic data at four different wavelengths simultaneously with a cross-validated PCA. The results of this study indicated that HPLC-PDA coupled with chemometrics could make a powerful discriminating tool for the forensic chemist, especially when analyzing extensive and/or complex data. 相似文献
Because of a shortage in the availability of human organs, xenografts have been attempted in humans with cardiac, renal, and hepatic failure, despite limited success. Use of xenografts, however, is regulated under law in various countries. In xenotransplant cases related to violation of transplantation law, determination of species of the source of tissue and organ(s) becomes highly essential. Random amplified polymorphic DNA (RAPD) protocols using six sets of arbitrary short-sequenced primers have been standardized for verifying claims of porcine cardiac and renal grafts in human transplantation cases. Six arbitrary primers used were found to generate unique amplicon patterns at 36 degrees C annealing temperature. Among the selected primers, a single primer set having the sequence 5'- GGTGCGGGAA -3' is found to be the most informative in discerning porcine tissue contamination in humans. The patterns obtained were consistent for a particular genome. The grafted organs in the studied case were analyzed to be of porcine origin. 相似文献
In 2005 Indonesian and European institutes joined to start the first step for the implementation of an Ocean Operational System
in the Indonesian archipelago. The system will support the decision making process for the sustainable use of marine resources,
providing useful information and added value products as well as a service for an improved management of the sea with high
business impact to targeted groups as public authorities and commercial operators (coastal managers, fishermen, shipping companies).
In this paper the System is shortly described with its potential benefits and economic and social impacts.
We discuss global options for initiatives intended to ameliorate adverse impacts of visa and work permit systems used by national
governments around the world. We first describe and document some of their effects, noting the relative lack of other research
work on these issues. We then discuss proposals for a new and supplemental global visa structure which have been made as part
of the Mode 4 GATS negotiations in the WTO, suggesting that the GATS/WTO may be an imperfect institutional location for negotiating
on these matters. We then evaluate other approaches, including what realistically could be possible if a new body specifically
created for global negotiation in the area were to be used.
This paper presents a theoretical framework and some empirical results showing that the level of foreign aid received reduces the supply of terrorist attacks by recipient countries, as does the recipient country’s level of education. Due account is taken of endogeneity problems in producing these results. They suggest that Western democracies, which are the main targets of terrorist attacks, should invest more funds in foreign aid with a special emphasis on supporting education. 相似文献
The flow of foreign direct investment into developing countries varies greatly across countries and over time. The political factors that affect these flows are not well understood. Focusing on the relationship between trade and investment, we argue that international trade agreements—GATT/WTO and preferential trade agreements (PTAs)—provide mechanisms for making commitments to foreign investors about the treatment of their assets, thus reassuring investors and increasing investment. These international commitments are more credible than domestic policy choices, because reneging on them is more costly. Statistical analyses for 122 developing countries from 1970 to 2000 support this argument. Developing countries that belong to the WTO and participate in more PTAs experience greater FDI inflows than otherwise, controlling for many factors including domestic policy preferences and taking into account possible endogeneity. Joining international trade agreements allows developing countries to attract more FDI and thus increase economic growth.相似文献