Urbanization and rural labor supply: A historical study of Bogotá, Colombia since 1920

The author examines how social and economic changes in rural Colombia have affected urban growth in Bogota in the 1920s and 1930s with growth after 1958. Data from both official statistics and published studies are used.     

Development and Validation of a Technique for Casting Anatomical Features and Toolmarks

Time may elapse between examination of marks inflicted on the body and comparison with a potential weapon. Two‐dimensional photographs may be inadequate for effective comparison of a three‐dimensional mark with a putative instrument. Taking a cast and producing a positive image results in a lasting three‐dimensional record. This project aimed to develop and demonstrate the accuracy of an easy technique for production of long‐lasting positive images (using plaster of Paris and dental alginate). Casts of facial features of embalmed cadavers were used to produce a positive image of the face (death mask). Measurements of distances between facial anatomical landmarks were compared with measurements of distances between the same landmarks on the death masks to assess accuracy of reproduction. There were no significant differences between cadaver and death mask in 6 of 9 measurements, indicating this technique has high accuracy with less mobile facial features, but produces deformation of pliable features.     

Who are the most highly cited forensic scientists in the United States?

The most highly cited forensic practitioners in the United States were identified using a publicly available citation database that used six different citation metrics to calculate each person's composite citation score. The publication and citation data were gleaned from Elsevier's SCOPUS database, which contained information about ~7 million scientist each of whom had at least five entries in the database. Each individual was categorized into 22 scientific fields and 176 subfields, one of which was legal and forensic medicine (LFM). The database contained citation records for 13,388 individuals having LFM as their primary research discipline and 282 of these (2%) were classified as being highly cited. Another 99 individuals in the database had LFM as their secondary discipline, making a total of 381 highly cited forensic practitioners from 35 different countries. The career-long publication records of each individual were compared using their composite citation scores. Of the 381 highly cited scientists, 93 (24%) had an address somewhere in the United States. The various branches of forensics they specialized in were anthropology, criminalistics, DNA/genetics, odontology, pathology, statistics/epidemiology, and toxicology. The two most highly cited scientists, according to their composite citation score, were both specialists in DNA/genetics. Bibliometric methods are widely used for evaluating research performance in academia and a similar approach might be useful in jurisprudence, such as when an expert witness is instructed to testify in court and explain the meaning of scientific evidence.     

Form follows function: Applying photographic content analysis to forensic firearm identification

Drawing forensic conclusions from an image or a video is known as “photographic content analysis.” It involves the analysis of an image, as well as objects, actions, and events depicted in images or video. In recent years, photographic depictions of objects suspected as illegal firearms have substantially increased, appearing on CCTV surveillance footage, captured by mobile phones and shared on social media. However, the law in Israel states that a person can be charged with illegally possessing a firearm only if it can be proven that the object is capable of shooting with lethal bullet energy. This becomes more challenging in cases where the firearm was not physically seized, and the evidence exclusively consists of images and video. In this study, photographic content analysis was applied to images and video where objects suspected as commercial or improvised firearms had been depicted. An image and event sequence reconstruction video databases of both firearms and replicas were created in order to better define firearm-specific functional morphological features. We demonstrate that it is possible to classify an object as a firearm by analyzing the functional, and not only the esthetic, morphology in images and video. It is also shown that event sequence reconstruction in video may be used to infer that an object suspected as a firearm has the capacity to shoot by confirming the occurrence of a shooting act or shooting process. Thus, photographic content analysis may be used to forensically establish that an object depicted in an image or a video is a firearm by ruling out other known scenarios, and without physically seizing it.     

The Capability of Raman Microspectroscopy to Differentiate Printing Inks

This study applies Raman microspectroscopy to differentiate the chemical components in printing inks of different brands, colors, and type using the 532 nm and 785 nm excitation wavelengths. Spectra were collected from 319 inks (78 inkjet, 76 toner, 79 offset, and 86 intaglio) representing various colors. Comparisons were performed to calculate discrimination capability percentages for each ink type. Overall, Raman microspectroscopy differentiates according to the following hierarchy: intaglio (96%), inkjet (92%), offset (90%), and toner (61%). The ability of Raman microspectroscopy to differentiate between same‐colored inks from different brands was dependent on the color and ink analyzed. Based on ink color, the discrimination capability ranged from 75 to 94% (inkjet), 0 to 86% (toner), and 0 to 77% (offset). Copper phthalocyanine was detected in cyan inks and various intaglio inks, while carbon black was identified in black inkjet, offset, and intaglio inks.     

Impacting the Political Landscape: Who Registers and Votes Among Naturalized Americans?

Little is known about the voting behavior of naturalized Americans, primarily due to a lack of good quality data on the national level. Using data from the Voting and Registration Supplement to the November 1996 Current Population Survey (CPS), we examine whether region of origin and length of time spent in the United States affect the likelihood of registering and voting among naturalized citizens, net of other socioeconomic and demographic factors already known to influence electoral behavior. We find that naturalized citizens who have a longer length of time at current residence and in the United States, and those who are older, with more education and higher income are more likely to register and vote. Region of origin is not a major explanatory variable, but there are differences in registering and voting by country of origin among naturalized citizens from Asia and Latin America. Finally, being registered is a necessary but not sufficient condition that predicts voting among naturalized citizens from Asia and from Latin America.