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Faruk Asicioglu M.D. Ph.D. Tugba Tekin M.Sc. Nil Ozbek Ph.D. Filiz Ekim Cevik Ph.D. Mustafa Ozcan Ph.D. Linton A. Mohammed Ph.D. 《Journal of forensic sciences》2019,64(6):1898-1905
Disappearing inks can be used for forgeries in many fields. In this study, thymolphthalein indicator solution was prepared as a disappearing ink. A total of 54 different solutions containing thymolphthalein were prepared at six different concentrations and nine different pH values. Among the prepared solutions, 0.16 g/50 mL and 0.32 g/65 mL thymolphthalein at pH 14 were the optimum solutions that were not distinguishable from regular ink when applied to promissory note. Fountain pens were filled with the abovementioned ink solutions and applied to promissory notes for experimental purposes. After 40 h, ink residues were not visible on promissory notes written with the ink with the optimum pH (pH = 14) value. To decipher the entries that disappeared, an instrumental method (Video Spectral Comparator‐8000) and a chemical method (using NH3 vapor) were used, succeeded at 0.32 g/65 mL, but failed at 0.16 g/50 mL thymolphthalein. Therefore, NH3 had to be sprayed for 0.16 g/50 mL with negligible harm. 相似文献
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F. Andrew Kozel M.D. M.S.C.R. Kevin A. Johnson Ph.D. Emily L. Grenesko B.A. Steven J. Laken Ph.D. Samet Kose M.D. Xinghua Lu M.D. Ph.D. Dean Pollina Ph.D. Andrew Ryan Ph.D. Mark S. George M.D. 《Journal of forensic sciences》2009,54(1):220-231
Abstract: Using Blood Oxygen Level Dependent (BOLD) functional MRI (fMRI) to detect deception is feasible in simple laboratory paradigms. A mock sabotage scenario was used to test whether this technology would also be effective in a scenario closer to a real‐world situation. Healthy, nonmedicated adults were recruited from the community, screened, and randomized to either a Mock‐crime group or a No‐crime group. The Mock‐crime group damaged and stole compact discs (CDs), which contained incriminating video footage, while the No‐crime group did not perform a task. The Mock‐crime group also picked up an envelope from a researcher, while the No‐crime group did not perform this task. Both groups were instructed to report that they picked up an envelope, but did not sabotage any video evidence. Participants later went to the imaging center and were scanned while being asked questions regarding the mock crime. Participants also performed a simple laboratory based fMRI deception testing (Ring‐Watch testing). The Ring‐Watch testing consisted of “stealing” either a watch or a ring. The participants were instructed to report that they stole neither object. We correctly identified deception during the Ring‐Watch testing in 25 of 36 participants (Validated Group). In this Validated Group for whom a determination was made, computer‐based scoring correctly identified nine of nine Mock‐crime participants (100% sensitivity) and five of 15 No‐crime participants (33% specificity). BOLD fMRI presently can be used to detect deception concerning past events with high sensitivity, but low specificity. 相似文献
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The Impact of Child‐Care Subsidies on Child Development: Evidence from Geographic Variation in the Distance to Social Service Agencies 下载免费PDF全文
In this paper, we examine the impact of U.S. child‐care subsidies on the cognitive and behavioral development of children in low‐income female‐headed families. We identify the effect of subsidy receipt by exploiting geographic variation in the distance that families must travel from home to reach the nearest social service agency that administers the subsidy application process. Using data from the Kindergarten cohort of the Early Childhood Longitudinal Study, our instrumental variables estimates suggest that children receiving subsidized child care in the year before kindergarten score lower on tests of cognitive ability and reveal more behavior problems throughout kindergarten. An auxiliary analysis of longer‐run outcomes shows that these negative effects largely disappear by the time children finish first grade. 相似文献