Controlled electrostatic methodology for imaging indentations in documents

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.     

Technical Note: Analyzing the effect of repeated fusing on toner to examine printing alterations made by the same laser printer

With continuous innovations in laser printing technology, the number of cases of falsification using laser printers is increasing annually. Difficulties in identifying printing alternations, especially laser-printed alternations by the same printer are increasing. Effectively, repeated printing on the same page by the same printer means the original toner on the document was fused repeatedly. Thus, this study mainly investigates the effects of second fusing on the microscopic morphology of toner to examine whether documents have been tampered with. To detect the influence of fusing on the microscopic morphology of toner, 170 documents printed by 17 different models of laser printers from 5 brands were studied. It was found that, according to microscopic observations, the micrographs of toner may become brighter, darker or both with repetition of the fusing process. By calculating the average gray value of the micrographs of toner, it was found that, in some laser printers, the gray value of the thermoplastic accumulation area will increase after a second fusing, and the gray value of the toner particle dispersion area will decrease. In conclusion, by comparing the micrographs of toner from suspicious and reliable contents on the same page or in the same document, together with the measurement and analysis of average gray values, it is possible to examine the once- and twice-fused document contents, and further determine whether the document has been altered.     

The Relationship of Chronological Age, Age at Injury, and Duration of Injury to Employment Status in Individuals with Spinal Cord Injury

Employment status following spinal cord injury (SCI) has important implications for financial and psychosocial well-being. Several age-related variables-in particular chronological age, duration of SCI, and age at SCI onset-have been identified as being associated with employment among individuals with SCI. Cross-sectional investigations of this topic are complicated by methodological and statistical issues associated with aging and disability. The purpose of the current study was to examine the associations between three aging variables and employment status in individuals with SCI through a series of regression analyses. Six hundred twenty individuals with SCI completed a survey that included measures of demographic characteristics, pain, psychological functioning, physical functioning, fatigue, and sleep. The results indicated that chronological age and age at SCI onset were significant predictors of employment status. A significantly greater proportion of individuals aged 45-54 were employed compared to those aged 55-64 even after controlling for biopsychosocial variables. Additionally, there was a negative linear relationship between percent employed and age at SCI onset, and this relationship was not accounted for by the biopsychosocial variables. The analyses used in this study provide one method by which to disentangle the effects of different age-related variables on important SCI outcomes in cross-sectional research. Continued research in this area is needed to better understand age-related effects on employment status, which could be used to help maximize the quality of life in individuals with SCI.     

Structural Covariates of Violent Crime Rates in Germany: Exploratory Spatial Analyses of Kreise

This research applies the techniques of exploratory spatial data analysis (ESDA) and spatial regression modeling to explain variation in robbery and assault rates across 413 districts or “Kreise” in Germany. The findings from ESDA reveal a distinct clustering of low rates in southern Germany, especially for robbery. The results of the spatial regression analyses indicate that for the nation at large, Kreise with high robbery and assault rates tend to be those with comparatively high levels of socioeconomic deprivation and a more urbanized environment, findings consistent with those commonly reported with data for areal units in the USA. We also observe net regional effects for the south in the regression models that pose puzzles for further inquiry into the German case, and “null effects” of the eastern region that have implications for more general debates of the potentially criminogenic consequences of the transition to market economies.     

Evaluation and comparison of the electrostatic dust print lifter and the electrostatic detection apparatus on the development of footwear impressions on paper

The Electrostatic Dust Print Lifter (EDPL) and the Electrostatic Detection Apparatus(2) (ESDA(2)) were compared to determine if both processes could be used to develop footwear impressions of the same or similar quality and in what order they should be used to develop the highest quality footwear impression. The sensitivity of each technique was also evaluated. The quality of the footwear impressions developed was determined by comparing 25 individual characteristics present on the known shoe to the footwear impressions developed using each technique. The footwear impressions were made by stepping on paper placed over several different surfaces, which included: linoleum, industrial Berber carpet, nylon carpet placed over a (3/8)-in. pad, ceramic tile, cardboard, 1-in. foam, 4-in. foam, cement, asphalt, grass, and mulch. Each of the papers placed on these surfaces was developed using the EDPL before the ESDA(2) and vice versa. The sensitivity test for the ESDA(2) was conducted by processing 10 sheets of stacked paper that were stepped on with the known shoe, beginning with the top sheet. The sensitivity test for the EDPL was conducted by processing 10 sheets of paper stepped on with the known shoe in succession. This study determined the footwear impressions developed using the EDPL were of better comparative value than impressions developed with the ESDA(2). On average, 72.4% of the individual characteristics from the known impression were identified on images developed when the EDPL was used first compared with an average of 38.9% when the ESDA(2) was used first. Therefore, if only one technique is used, the EDPL should be chosen. The sensitivity test determined the ESDA(2) develops high-quality footwear impressions on only the top sheet of paper. No footwear impressions were developed on any sheets under the top sheet of paper. The sensitivity test also determined the EDPL results increase in quality as the amount of dust residue decreases on the surface.     

Determination of the Sequence of Intersecting Lines Between Toners and Seals by Laser Fluorescence Microscope

Fluorescence microscope is considered to be one of the most effective ways to examine the sequence of intersecting seal and toner lines of questioned documents. In reality, however, the toner (mainly divided into compact and noncompact toners) and seal of a questioned document have such a complex morphology and sequence of crossing lines that current methods cannot meet the requirement of practical document identification. In view of the challenges of document examination, a laser fluorescence microscope and method are developed in this study. The developed microscope provides additional functionality to traditional fluorescence microscopes of transmitted light modality, laser excitation, selectable excitation wavelength, and selectable fluorescence filters. The results obtained from the method of comparisons between transmitted light and fluorescence modalities were positive under most conditions, particularly for noncompact toner examination for which a 100% accuracy rate and 90% detection rate were achieved in blind testing.     

Latent Fingermark Aging Patterns (Part III): Discontinuity Index as One Indicator of Degradation

This article is the third in a series of reports exploring quantifiable visual parameters of the aging process of latent fingermarks. On this occasion, research is focused on the occurrence of ridge discontinuities (i.e. breakages) as a function of time. Experiment variables included type of secretion (eccrine and sebaceous), substrate (glass and plastic), and exposure to natural light (dark, shade, and direct light) over a 6 months period. Fingermarks were sequentially visualized with titanium dioxide powder, photographed, and the number of naturally occurring ridge discontinuities subsequently evaluated. A semi‐quantitative value, named Discontinuity Index, was used to better characterize this aging parameter. Results indicated that ridges of sebaceous depositions on glass were generally less affected by the environmental conditions compared with those on plastic surface. In addition, aging in darkness was not always the best condition for preservation, and the direct exposure to light seemed not to affect the degradation under certain conditions.     

微束X射线荧光分析法鉴别激光打印机墨粉的研究

目的利用微束X射线荧光分析法（μ-XRF）研究激光打印机用墨粉的鉴别。方法利用μ-XRF对9台不同型号激光打印机用墨粉、对应的打印字迹、提取的字迹墨粉所含元素进行定性、半定量的分析。结果根据检出元素种类的不同,可将9台不同型号激光打印机用墨粉、对应的打印字迹、提取的字迹墨粉分成7类、4类、4类,区分率分别为94.4%、75%、69.4%。结论本研究所建立的μ-XRF鉴别激光打印机墨粉方法具有微区、原位无损检验等优点,对提高激光打印文件检验水平具有现实意义。     

The Stability of Collected Human Scent Under Various Environmental Conditions*,†

Abstract: Human scent evidence collected from objects at a crime scene is used for scent discrimination with specially trained canines. Storage of the scent evidence is usually required yet no optimized storage protocol has been determined. Storage containers including glass, polyethylene, and aluminized pouches were evaluated to determine the optimal medium for storing human scent evidence of which glass was determined to be the optimal storage matrix. Hand odor samples were collected on three different sorbent materials, sealed in glass vials and subjected to different storage environments including room temperature, ?80°C conditions, dark storage, and UVA/UVB light exposure over a 7‐week period. Volatile organic compounds (VOCs) in the headspace of the samples were extracted and identified using solid‐phase micro‐extraction–gas chromatography/mass spectrometry (SPME–GC/MS). Three‐dimensional covariance mapping showed that glass containers subjected to minimal UVA/UVB light exposure provide the most stable environment for stored human scent samples.     

Toner Particles as Forensic Evidence: Microanalytical Characterization of Known Toner and Recognition of Toner in Environmental Samples*†‡

Modern printing toners represent a prime example of subvisible particles that can be easily transferred to hands, clothing, and other surfaces. To explore the potential evidentiary value of toner particles, toner samples were collected from known printer cartridges and characterized by various microanalytical techniques to establish the properties most useful for recognition, identification, and comparison. Environmental samples (i.e., dust) were then collected from various locations at varying distances from toner-based printers, using both tape lifts and carbon adhesive stubs, to assess the possibility of detecting toner. By light microscopy, toner can be recognized on the basis of particle size and shape, as well as color. Further examination of the micromorphology in the field emission scanning electron microscope reveals characteristic morphologies and differences in surface texture and shape among toner sources. Raman spectroscopy provides chemical identification of the pigment (or pigment class) and, in some cases, also permits identification of the polymer component. While black and blue pigment chemistry remained constant among toner varieties that were studied (copper phthalocyanine and carbon black), variation in yellow and magenta pigments was observed. Analysis of dust samples collected from various environments demonstrated that while toner is consistently detectable in close proximity to printers (within 2 feet), it also can be detected in dust collected in nearby rooms. This research demonstrates that toner particles can be located, characterized, and discriminated, using a suite of microanalytical methods that are applicable to forensic casework.     

How long after writing can an ESDA image be developed?

ESDA has been used for a number of years as a means of developing indented images on paper and is an essential tool for the document examiner. This paper reports on the results of experiments with various aged documents to determine how long after writing images can be developed with ESDA. The results indicate that the latent image from some writing may remain longer than fifty years. The paper also reports an actual case in which images were developed years after the document was executed, thus dating the preparation of key pages.     

Dental and Chronological Age in Children Under Oncological Treatment

The current oncology treatment has improved the survival of children with several types of cancer, and the effect of radiotherapy and/or chemotherapy treatment on dental maturation in comparison with chronological age is not widely known. The aim of this work was to evaluate and compare the impact of radiotherapy and/or chemotherapy treatment during dental maturation with chronological age in Chilean children diagnosed with cancer. Study Design was cross‐sectional study on children diagnosed with different types of cancer and treated with radiotherapy and/or chemotherapy when they were ages of 0.1 to 13 years. Demirjian tables for both girls and boys are used to determine the dental age. The association between chronological and dental age was highly significant. Nevertheless, a linear relation between chronological and dental age was not observed when the data were stratified by BMI and type of treatment. This study confirmed that dental age is an indicator of chronological age but that other variables, such as body mass index, in children with cancer could be confounder variables. Thus, further studies are necessary to investigate the influence of BMI on tooth eruption/maturation in children under oncological treatment.     

Determining Line-Crossing Sequences Between Laser Printing and Writing Pen Using Coaxial Light

Determining the application sequence of hand-written pen ink and printer toner lines has attracted significant interest in questioned document examination. This study uses coaxial light to determine line-crossing sequences, with intersections observed under a VSC600 forensic document workstation and a Leica M205A Stereo-microscope. Results show that reflected light at intersections and color contrast between intersections and nonintersections was observed when a hand-written ink line passes over a toner line, while a toner line passing over a written line appeared dull, with no color contrast. The procedure was tested under a range of conditions, such as types of writing pens and laser printers, the writer, and writing pressure, with the latter playing an important role in the evaluation. To validate the results, a 90% detection rate and 98% accuracy rate were achieved from 50 samples of blind testing, which is more effective than optical microscopy.     

Determination of the sequence of intersecting lines from laser toner and seal ink by Fourier transform infrared microspectroscopy and scanning electron microscope / energy dispersive X-ray mapping

The aim of this study was to verify that the combination of Fourier transform infrared microspectroscopy and scanning electron microscope / energy dispersive X-ray mapping could be applied to line intersection problems. The spectral data of red seal ink, laser toner and their intersections, such as peak location and peak intensity, were described. Relative peak height ratios of different chemical components in intersecting lines were used to distinguish the sequences. Energy dispersive X-ray mapping characteristics of intersecting areas were also detailed. The results show that both the laser toner and the seal ink appear on the surface of intersections, regardless of the sequence. The distribution of the two inks on the surface is influenced not only by the sequence of heterogeneous lines but also by diffusion. Fourier transform infrared microspectroscopy and scanning electron microscope/energy dispersive X-ray mapping are able to explore the chemical components and the corresponding elemental distribution in the intersections. The combination of these two techniques has provided a reliable method for sequencing intersecting lines of red seal ink and laser toner, and more importantly, this method may be a basis for sequencing superimposed lines from other writing instruments.     

Effects of histological staining on the analysis of human DNA from archived slides

Abstract: Archived slides of cell smears treated with histological stains for sperm detection are often the only source of DNA available when cold cases are reopened. There have been conflicting reports as to the negative effects of particular histological stains on DNA recovery and quality from human cells, making stain selection an important consideration for forensic laboratories. This study investigates the effect of several staining systems on DNA recovery from histological slide samples stored from 0 to 10 weeks. DNA profiles obtained after analysis of these samples with AmpFlSTR^® Identifiler? and increased cycle AmpFlSTR^® SGM Plus? short tandem repeat (STR) profiling systems and the effects that these stains have on DNA quantity and quality over time are described. Results indicate that Christmas Tree and Hematoxylin and Eosin stains do not have significantly different effects on DNA quality after 10‐week storage of slides. This research will assist scientists to select staining systems that have minimal deleterious effects on the DNA recovered.     

New formulae for estimating age-at-death in the Balkans utilizing Lamendin's dental technique and Bayesian analysis

The present study analyzed apical translucency and periodontal recession on single-rooted teeth in order to generate age-at-death estimations using two inverse calibration methods and one Bayesian method. The three age estimates were compared to highlight inherent problems with the inverse calibration methods. The results showed that the Bayesian analysis reduced severity of several problems associated with adult skeletal age-at-death estimations. The Bayesian estimates produced a lower overall mean error, a higher correlation with actual age, reduced aging bias, reduced age mimicry, and reduced the age ranges associated with the most probable age as compared to the inverse calibration methods for this sample. This research concluded that periodontal recession cannot be used as a univariate age indicator, due to its low correlation with chronological age. Apical translucency yielded a high correlation with chronological age and was concluded to be an important age indicator. The Bayesian approach offered the most appropriate statistical analysis for the estimation of age-at-death with the current sample.     

Visualising the past – An evaluation of processes and sequences for fingermark recovery from old documents

This study aimed to collect data on the effectiveness of most of the fingermark visualisation reagents currently used on porous surfaces on fingermarks aged for up to 90?years, significantly extending the timescales for which such information exists. A limited subset of the variables associated with processing of old fingermarks was explored, with a focus on the use of 1,8 diazafluoren-9-one (DFO), 1,2-indandione, ninhydrin, and physical developer. These techniques were used in sequence on batches of cheques between 11 and 32?years old, and on documents dating from the 1920s and 1940s. The potential for applying a physical developer enhancement process (blue toning) as the final step in the sequence was also explored. The benefits of using processing sequences on porous items were clearly demonstrated, with all processes in the sequence adding value in terms of additional marks found on the cheques up to 32?years old. In addition, physical developer was found to be capable of developing fingermarks up to 90?years old, whereas the amino acid reagents appear less effective on documents of 70?years and older. An experimental physical developer formulation with reduced environmental impact was found to be as effective as the existing process in these experiments. Blue toning was found to visualise an additional 10–25% of marks, and its wider use after silver-based deposition processes is recommended based on the evidence from this study.     

论研究船舶污染事故中船员犯罪问题的意义

海洋环境污染已成为国际社会广泛关注的问题.基于海洋对于人类的重要性和海洋环境污染的严重程度,国际社会意识到要为海洋建立一种法律秩序,以便利国际交通和促进海洋的和平用途,海洋资源的公平而有效的利用,海洋生物资源的养护以及研究、保护和保全海洋环境. 这种法律秩序体系庞大,涉及到海洋开发、利用和保护的方方面面.海洋环境污染事故发生后有关行为人犯罪及刑事责任的问题,也当然被包含在这个法律秩序当中.分析研究船舶污染事故中船员犯罪问题的重要意义.     

A Bargaining Model of Holdouts and Takings

The holdout problem is commonly cited as the justification foreminent domain, but the nature of the problem is not well understood.This article models the holdout problem in a bargaining framework,where a developer seeks to acquire several parcels of land fora large-scale development. We show that in the absence of eminentdomain, holdouts are a significant threat, resulting in costlydelay. However, if the developer has the power to use eminentdomain to acquire the land from holdouts, all sellers will bargain,thus avoiding delay. An offsetting cost is that owners may negotiateprices below their true value, possibly resulting in excessivetransfer of land to the developer.