NIST bullet signature measurement system for RM (Reference Material) 8240 standard bullets

A bullet signature measurement system based on a stylus instrument was developed at the National Institute of Standards and Technology (NIST) for the signature measurements of NIST RM (Reference Material) 8240 standard bullets. The standard bullets are developed as a reference standard for bullet signature measurements and are aimed to support the recently established National Integrated Ballistics Information Network (NIBIN) by the Bureau of Alcohol, Tobacco and Firearms (ATF) and the Federal Bureau of Investigation (FBI). The RM bullets are designed as both a virtual and a physical bullet signature standard. The virtual standard is a set of six digitized bullet signatures originally profiled from six master bullets fired at ATF and FBI using six different guns. By using the virtual signature standard to control the tool path on a numerically controlled diamond turning machine at NIST, 40 RM bullets were produced. In this paper, a comparison parameter and an algorithm using auto-and cross-correlation functions are described for qualifying the bullet signature differences between the RM bullets and the virtual bullet signature standard. When two compared signatures are exactly the same (point by point), their cross-correlation function (CCF) value will be equal to 100%. The measurement system setup, measurement program, and initial measurement results are discussed. Initial measurement results for the 40 standard bullets, each measured at six land impressions, show that the CCF values for the 240 signature measurements are higher than 95%, with most of them even higher than 99%. These results demonstrate the high reproducibility for both the manufacturing process and the measurement system for the NIST RM 8240 standard bullets.     

SWGDAM developmental validation of a 19-locus Y-STR system for forensic casework

A Scientific Working Group on DNA Analysis Methods (SWGDAM) developmental validation study was carried out on two Y-STR multiplex systems (MPI and MPII) that collectively permit the co-amplification of 19 Y-STR markers, including DYS393, DYS392, DYS391, DYS389I, DYS389II, Y-GATA-A7.2 (DYS461), DYS438, DYS385a and DYS385b (MPI); DYS425, DYS388, DYS390, DYS439, DYS434, DYS437, Y-GATA-C.4, Y-GATA-A7.1 (DYS460), Y-GATA-H.4, and DYS 19 (MPII). Performance checks subsequent to PCR parameter optimization indicated that MPI and MPII were suitably reproducible, precise and accurate for forensic use. The sensitivity of the systems was such that a full 19-locus Y-STR profile was obtainable with 150-200 pg of male DNA, and some loci were detectable even with as little as 20-30 pg of input DNA. Primate specificity was demonstrated by the lack of cross-reactivity with a variety of commonly encountered bacterial and animal species, with the single exception of a monomorphic canine product that was outside of the size range of human alleles from any of the 19 loci. Not surprisingly, cross-reactivity was observed with a number of male and female nonhuman primates. Environmentally compromised samples produced full or partial Y-STR profiles. For example, a semen stain exposed to the outdoor elements for six months still gave a 13-locus Y-STR profile. Although a limited number of female DNA artifacts were observed in mixed stains in which the male DNA comprised 1/300 of the total, the full 19-locus male profile was easily discernible. Even at a 1500-to-2000-fold dilution of male DNA with female DNA partial Y-STR profiles were obtained. Furthermore, the potential utility of MPI and MPII for forensic casework is exemplified by their ability to dissect out the male haplotype in a variety of case-type samples, including, inter alia, post-coital vaginal swabs, admixed male and female bloodstains, the nonsperm fraction from a differentially extracted semen stain, and determination of the number of male donors in mixed semen stains.     

Laser microdissection separation of pure spermatozoa from epithelial cells for short tandem repeat analysis

Short tandem repeat (STR) analysis is a valuable tool in identifying the source of biological stains, particularly from the investigation of sexual assault crimes. Difficulties in analysis arise primarily in the interpretation of mixed genotypes when cell separation of the sexual assailant's sperm from the victim's cells is incomplete. The forensic community continues to seek improvements in cell separation methods from mixtures for DNA typing. The feasibility of applying laser microdissection (LMD) technology to precisely separate sexual assault cell mixtures by visual inspection coupled with laser dissection was assessed through three experiments. First, various histological stains were evaluated for use with LMD and DNA analysis. Second, different DNA isolation methods were evaluated on LMD-collected cells. Finally, STR analysis was performed on LMD-separated sperm cells from mixtures of semen and female buccal epithelial cells. The results indicated (a) hematoxylin/eosin staining performed best in its ability to differentiate sperm and epithelial cells while exhibiting the least negative effect on further downstream analysis; (b) both QIAamp and Lyse-N-Go methods were useful for recovery of DNA from LMD-collected sperm cells; and (c) LMD separation provided clear STR profiles of the male donor with the absence of any additional alleles from the female donor. This report describes an efficient, low-manipulation LMD method for the efficient separation of spermatozoa from two-donor sperm/epithelial cell mixtures.     

A comparison of carboxyhemoglobin saturation values in postmortem heart blood and peripheral blood specimens

The following is a study conducted to determine whether there was any significant difference in carboxyhemoglobin (COHb) saturation levels between the heart blood and blood collected from a peripheral site. The average heart blood to peripheral blood COHb saturation level ratio in the 42 cases studied was 1.09. Sixty-two percent (26 of 42) of the cases had a heart blood to peripheral blood ratio between 0.9 and 1.1; 74% (31 of 42) had a ratio between 0.8 and 1.2. Eighty-three percent (35 of 42) had a ratio between 0.7 and 1.3. There were four cases where the heart blood to peripheral blood ratio was either below 0.6 or greater than 1.4. The differences between the two sites were not statistically significant.     

Undergraduate justice system education and training at San Jose state university: An historical perspective

Since its inception in 1930, the Administration of Justice Department at San Jose State University has undergone numerous changes. This article develops a curriculum orientation matrix to analyze those changes. The results of the application of the matrix indicate movement from a law enforcement, training emphasis to the present system-oriented, professional-social science mix.     

Information flow from Japan to U.S. researchers in applied and basic energy research fields

A recent study conducted by Pacific Northwest Laboratory (PNL) evaluated technical information transfer from Japan to the United States. This evaluation was part of a larger assessment of international monitoring of energy technology development conducted for the U.S. Department of Energy. For this study, U.S. researchers in each of ten selected technical fields were identified and interviewed to obtain their perceptions of information transfer from Japan. Results from these interviews indicated that, although there are major differences among the technical fields, U.S. researchers generally consider information transfer from Japan to the U.S. to be inadequate. Researchers particularly noted the difficulties they have attending conferences in Japan or visiting Japanese research facilities. In contrast, Japanese researchers attend all major conferences and frequently visit laboratories in the U.S. Researchers recommended several steps to improve technology transfer from Japan, including improving the screening and translation of technical material published in Japan, promoting binational seminars and workshops, and encouraging laboratory visits and exchanges of research personnel.     

Prevalence and patterns of substance use among early adolescents

Prevalence and patterns of substance use are described for a sample of 105 San Francisco East Bay adolescents (age 14). Data are compared with national statistics on substance use among high school seniors. While alcohol use appeared comparable to the national statistics, tobacco use was less prevalent among this younger western sample. Despite the differences in ages, use of marijuana, cocaine, and hallucinogens was similar to national high school prevalence; use of other harder drugs was more extensive among the older, national sample. Contrary to typical findings, males and females were not found to differ in frequency or extent of substance use; females appeared somewhat more involved in substance use at this early age. Initiation of substance use occurred at early grade levels, suggesting that intervention efforts should begin prior to junior high, perhaps as early as fourth or fifth grade.This study was supported by National Institute of Mental Health Grant MH 16080 to Jack Block and Jeanne H. Block.Received her Ph.D. from Harvard University. Main interest is cognitive development and development in adolescence.Received his Ph.D. from Stanford University. Main interest is personality development.     

The criminal investigative process: Toward a conceptual framework

There have been few attempts to develop a conceptual framework of the criminal investigation process. This article attempts to develop such a framework through use of a criminal act continuum to identify intervention points as these relate to investigative techniques and information sources. Criminal investigation is then considered within a political context to identify eight investigative subprocesses, each of which poses varying degrees of risk to democratic social systems.