An evaluation of matching unknown writing inks with the United States International Ink Library

Utilizing a database of standards for forensic casework is a valuable resource. Undoubtedly, as more standards (and corresponding information about the specimens) are collected, there is a greater certainty of identification when a questioned and a known item cannot be distinguished after a series of analyses. The United States Secret Service and the Internal Revenue Service National Forensic Laboratory jointly maintain the largest known forensic collection of writing inks in the world, which is comprised of over 8500 ink standards collected worldwide, dating back to the 1920s. This study was conducted to evaluate the reliability of matching arbitrarily purchased pens with known inks from a database. One hundred pens were randomly obtained from a variety of sources and their respective ink compositions were compared with standards. Eighty-five of the inks were determined to be suitable for comparison utilizing optical examinations and thin-layer chromatography. Three of the inks did not match any of the specimens on record; one of these inks was similar to an ink from an identical brand of pen that was in the database, but had a modified formulation.     

Performance evaluation of the Scent Transfer Unit (STU-100) for organic compound collection and release

The Scent Transfer Unit (STU-100) is a portable vacuum that uses airflow through a sterile gauze pad to capture a volatiles profile over evidentiary items for subsequent canine presentation to assist law enforcement personnel. This device was evaluated to determine its ability to trap and release organic compounds at ambient temperature under controlled laboratory conditions. Gas chromatography-mass spectrometry (GC-MS) analyses using a five-component volatiles mixture in methanol injected directly into a capture pad indicated that compound release could be detected initially and 3 days after the time of collection. Additionally, 15 compounds of a 39-component toxic organic gaseous mixture (10-1000 parts per billion by volume [p.p.b.(v)]) were trapped, released, and detected in the headspace of a volatiles capture pad after being exposed to this mixture using the STU-100 with analysis via GC-MS. Component release efficiencies at ambient temperature varied with the analyte; however, typical values of c. 10% were obtained. Desorption at elevated temperatures of reported human odor/scent chemicals and colognes trapped by the STU-100 pads was measured and indicated that the STU-100 has a significant trapping efficiency at ambient temperature. Multivariate statistical analysis of subsequent mass spectral patterns was also performed.     

Tetrahydrocannabinols in hair of hashish smokers

The study investigates the presence of tetrahydrocannabinols in the head hair and the pubic and axillary hair. The hair samples were obtained from hashish smokers. The concentrations were determined by radioimmunoassay and reflect total tetrahydrocannabinols and metabolites. The values found ranged from 0.4 ng/mg hair up to 3.8 ng/mg hair. The presence of the drug in the hair samples was also demonstrated by GC/MS.     

CROSS-SUBSIDY ANALYSIS WITH MORE THAN TWO SERVICES

Thirty years have passed since the publication of "Cross-Subsidization:Pricing in Public Enterprises." The article rigorously definedcross-subsidization and is now a standard citation of regulatorsand scholars addressing the pricing of regulated multiproductfirms. The incremental cost test and the stand-alone cost test,however, have often been misunderstood and misapplied. Thisarticle answers the most common questions that have arisen inthe application of these tests for cross-subsidization and correctsthe most common errors that have been committed in their application.     

Mara Salvatrucha: The Most Dangerous Street Gang in the Americas?

Mara Salvatrucha (MS‐13), founded in 1980s Los Angeles by Salvadoran immigrant youth, is today one of the largest street gangs in North and Central America. In recent years the group has acquired a reputation for extreme brutality and has ostensibly mutated into a fast‐expanding, transnational organized crime network with possible ties to international terrorists. Drawing on key concepts in gang research and multiple methodological tools, this article seeks to sharpen understanding of MS‐13's structure and activities. While the group is active in many countries, it is transnational only in a symbolic manner, not in its configuration or span of authority. Impelled largely by Central American gang‐suppression policies, MS‐13 has evolved from a traditional street gang into a group with organized crime characteristics, but it remains a social phenomenon rooted in urban marginality. Ultimately, a more nuanced picture of Mara Salvatrucha can inform the search for more effective gang policies.