Correlates of handgun carrying among adolescents in the United States

Weapon-related violence, especially the use of handguns, among adolescents is a serious public health concern. Using public-use data file from the adolescent sample (N = 17,842) in the 2008 National Survey on Drug Use and Health (NSDUH), this study examines the behavioral, parental involvement, and prevention correlates of handgun carrying. Overall, 3.1% of adolescents between the ages of 12 and 17 reported carrying a handgun in the past year. Results from a series of logistic regression models indicated that males, selling and using illicit drugs, were robustly associated with an increased probability of handgun carrying among adolescents. Furthermore, youth who carry handguns were significantly less likely to report a parent being involved in their lives and were significantly more likely to have encountered violence and drug prevention programming compared with youth who did not carry handguns. Implications of these results for prevention and policy are discussed.     

CRIMES, DISORDERS, AND THE DEMAND FOR HANDGUNS: An Empirical Analysis

In a recent paper, Bordua and Lizotte (1979) analyze determinants of firearm ownership using cross-sectional data for Illinois counties. Noting that firearms may be purchased for the purpose of sport, self-protection, or crime, they present clear evidence of sporting demand and limited evidence of defensive motives in the pattern of gun ownership. Crime rates are significant only in the equation explaining gun ownership by women (1979: 161). The purpose of the present article is to supplement the findings of Bordua and Lizotte and earlier empirical studies by focusing on the demand for handguns alone. In particular, the article analyzes the role of crime rates and fear of violence in motivating citizens to buy and keep handguns. For this purpose, aggregate time-series and cross-sectional data on handgun sales were collected and analyzed. Because handguns are durable pieces of equipment, it is necessary to use a model that distinguishes the stock of handguns at any one time from the rate of handgun purchases.     

MEASURING PROTECTIVE HANDGUN OWNERSHIP*

Hill et al. (1985) have suggested a measure of protective handgun ownership that can be implemented in an omnibus survey like the General Social Survey (GSS), which does not ask respondents why they own the gun. Using the 1980 GSS and their refined measure, Hill et al. report (among other things) that fear of crime and prior victimization increase the likelihood that men, but not women, will own handguns for protection. Their analysis, however, is Jawed because (1) they made errors in their analysis and (2) their measure of protective handgun ownership is biased. This paper explains why the measure is biased and shows how the measure alters parameter estimates.     

Mineralogical and elemental data for soil discriminating and geolocation tracing

One of the key tasks of soil analysis in forensic sciences is to provide information about its diversities and geolocation. In fact, soil analysis is relevant for forensic geologists. In this study, a total of 80 soil samples were collected from eight Chinese cities (10 samples per city). Different minerals and their relative percentages were analyzed by the X-ray diffraction (XRD) method. In addition, the relative amounts of montmorillonite, kaolinite, amphibole, feldspar, calcite, and dolomite provided information about the origin of a soil, either if it came from a northern or southern city of China. The oxide weight percentages of 10 elements of Al₂O₃, SiO_2, Fe₂O₃, K₂O, Na₂O, MgO, CaO, P₂O₅, MnO, and TiO₂ were also obtained by using X-ray fluorescence (XRF) from the 80 soil samples. Moreover, principal component analysis (PCA) and hierarchical clustering analysis (HCA) methods were performed for dimensionality reduction, elemental marker identification and soils classification to the city they came from purposes. The eighty soils analyzed in this study could be tracked correctly to their city of origin. The K-Nearest Neighbors (KNN) model was done to evaluate the prediction ability based on the soil elemental composition, and it was confirmed by cross validation methods. The results demonstrated that mineralogical and elemental composition can provide powerful information for soil discrimination and source tracing.     

Transfer of Triazine‐iron(II) Chromic Complexes Left by Iron Items on Textile Background and Human Skin

Abstract: The research is focused on the detection and transfer of iron traces left by iron items on clothing and human skin. The method is based on the formation of colored complexes between ferrous ions and five synthesized, mostly new triazines. Iron traces originally were left by iron rings on slightly wetted (artificial sweat) cotton fabrics and subsequently transferred to a separate textile substrate. Prior to the use of trazines the contact spots were treated with a new inorganic reducing agent (Sn²⁺) to reduce Fe³⁺ to Fe²⁺. The method is sensitive to detect iron traces on wetted canvas after 10 min contact with iron items. More spectacular results were obtained for traces left on human palm even after very short contact (10 sec). The new iron‐trace‐transfer method eliminated the contact of triazines solutions with human skin. Transmission visible spectra of Fe(II)–triazine complexes were determined.     

Development of Latent Fingermarks on Various Surfaces Using ZnO‐SiO2 Nanopowder

Fingermarks are one of the most useful forms of evidence in identification and can provide generalized proof of identity in crime investigation. They are developed using various conventional powders. The novel nanopowder ZnO‐SiO₂ was synthesized via the conventional heating method and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy‐dispersive X‐ray (EDX) analysis, transmission electron microscope (TEM), and X‐ray diffraction (XRD). The mean particle size of ZnO‐SiO₂ nanopowder calculated through TEM was 32.9 nm. The development of fingermarks was carried out by powder dusting and small particle reagent (SPR) methods. Powder dusting method was used for the development of latent fingermarks on various dry, nonporous, and semi‐porous surfaces. The SPR method was also applied to wet nonporous surface. The developed latent fingermarks using ZnO‐SiO₂ nanopowder were found to have excellent quality with very clear third‐level ridges detail and had better visibility than commercially available white powder.     

Elemental analysis of soil samples for forensic purposes by inductively coupled plasma spectrometry — precision considerations

Major and trace elemental composition provides a powerful basis for forensic comparison of soils, sediments and rocks. However, it is important that the potential ‘errors’ associated with the procedures are fully understood and quantified, and that standard protocols are applied for sample preparation and analysis. This paper describes such a standard procedure and reports results both for instrumental measurement precision (repeatability) and overall ‘method’ precision (reproducibility). Results obtained both for certified reference materials and example soils show that the instrumental measurement precision (defined by the coefficient of variation, CV) for most elements is better than 2–3%. When different solutions were prepared from the same sample powder, and from different sub-sample powders prepared from the same parent sample, the CV increased to c. 5–6% for many elements. The largest variation was found in results for certified reference materials generated from 23 instrument runs over an 18 month period (mean CV = c. 11%). Some elements were more variable than others. W was found to be the most variable and the elements V, Cr, Co, Cu, Ni and Pb also showed higher than average variability. SiO₂, CaO, Al₂O₃ and Fe₂O₃, Rb, Sr, La, Ce, Nd and Sm generally showed lower than average variability, and therefore provided the most reliable basis for inter-sample comparison. It is recommended that, whenever possible, samples relating to the same investigation should be analysed in the same sample run, or at least sequential runs.     

A Comparison of Fingerprint Sweat Corrosion of Different Alloys of Brass

Fingerprint sweat from 40 donors was deposited onto samples of five α and α + β phase brasses, comprising five alloys with different copper and zinc concentrations, two of which also had the addition of small concentrations of lead. Visual grading of the visibility of the corrosion revealed that brasses with the least amount of zinc produced the most visible and fully formed fingerprints from the most donors. Consideration of previously reported mechanisms for the corrosion of brass suggests red copper (I) oxide as a likely corrosion product for low zinc brasses, and a consideration of the color, composition, and solubility of fingerprint sweat corrosion products suggests that copper (I) oxide produces good contrast and visibility with the brass substrate. Scanning electron microscope images of the corrosion of all five alloys confirmed the enhanced contrast between corroded and uncorroded areas for low zinc alloys.     

Identification of firearms holders by the [Fe(PDT)3](+2) complex. Quantitative determination of iron transfer to the hand and its dependence on palmar moisture levels

Quantitative data are reported for the first time on the amounts of iron, which are transferred to the hand upon holding a firearm. Iron levels between 21-315 ng/cm2 were found on volunteers' palms after a single holding of a handgun. Determination of the iron traces was accomplished spectrophotometrically using 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT) as a complexing agent. The transfer of iron from firearms to the palm was found to be, by and large a chemical (dissolution) rather than mechanical dislodgement. The prime factor that determines the amount of iron transferred from the firearm to the hand is the moisture level on the palm. These findings are likely to be of importance in courts of law, as well as in the war against terrorism and serious crime.     

A Systematic Study to Understand the Effects of Particle Size Distribution of Magnetic Fingerprint Powders on Surfaces with Various Porosities

This study intends to design magnetite (Fe₃O₄)‐based magnetic fingerprint powders with different particle size distributions. It also investigates the influence of particle size distribution on the visualization of latent fingermarks with as little background staining as possible on the surfaces with various porosities in a systematic way. Two strategies were used to prepare the magnetic fingerprint formulations for this study: milling of coarse magnetite particles for different durations, and mixing of sieved fine particles with different size ranges with coarse particles. Particle size analyses of the prepared magnetic powders, optical microscopy‐based roughness analysis of the surfaces and SEM measurements of the visualized fingerprints and representative powders were performed. Mag2 of the formulations prepared through milling and Mag5 and Mag6 of the formulations prepared through sieving and mixing were more successful in the development of latent prints than the rest of the solutions.     

Nitrous Oxide Determination in Postmortem Biological Samples: A Case of Serial Fatal Poisoning in a Public Hospital*

Abstract: In a public hospital, eight cases of fatal poisoning by nitrous oxide (N₂O) occurred under oxygen administration, due to an erroneous swapping of the lines in the gas system. The aim of the study was to clarify the factors involved in asphyxia by characterizing gases from different lines and measuring N₂O concentrations in postmortem biological samples from bodies exhumed. Analyses carried out on the gas system confirmed the erroneous substitution of O₂ line with N₂O and air line with O₂. Consequently, high N₂O amounts were revealed in several tissues and gaseous biological samples. All specimens were analyzed by headspace gas chromatography technique. A rigorous quantitative analysis was possible only in blood (11.29–2152.04 mg/L) and urine (95.11 mg/L) and in air samples from stomach and trachea (from 5.28 to 83.63 g/m³). This study demonstrates that N₂O can be detected in biological samples even 1 month after death.     

Weapon location following suicidal gunshot wounds

The location of the gun following suicidal gunshot wound was studied by reviewing 574 such deaths in which the scene was investigated by a medical examiner investigator and the body was examined at the Bexar County Medical Examiner's Office in San Antonio, Texas. The position of the gun could not be established in 76 cases. In the remaining 498 cases, the gun remained in the deceased's hand in 24% of the cases. In 69% of the cases, the gun was on or near the body but not in the hand (i.e., touching the body or within 30 cm of the body). The gun was found >30 cm from the body in the remaining 7% of cases. In the case of handguns, the gun was found in the hand in 25.7% of individuals. For individuals using long guns, the firearm was in the hand of the decedent in 19.5% of cases. The gun had a greater chance of remaining in the deceased's hand if the person was lying or sitting when the gunshot wound was received. Variables such as gender of the individual, wound location, and caliber of handgun were not significant in predicting whether the gun stayed in the hand after a suicidal gunshot wound.     

Magnetic Fingerprint Powder from a Mineral Indigenous to Thailand

Abstract: A study was conducted to investigate whether natural magnetite (Fe₃O₄), which is an abundant mineral in Thailand, could be used as a magnetic powder in the detection of latent fingerprints. Because of the presence of impurities, powdered magnetite is only weakly attracted by a magnet and cannot be used as a magnetic fingerprint powder by itself. Mixing a small amount of magnetite powder with nickel powder greatly enhances the magnetic attraction. A mixture of magnetite powder and nickel powder in a mass ratio of approximately 1:100 was found to be suitable for use as a magnetic fingerprint powder. Fingerprints developed using the magnetite/nickel mixture on nonporous surfaces were found to exhibit good adherence and clarity. Using an automated fingerprint identification system, the number of minutiae detected in fingerprints developed by using the prepared powder on nonporous surfaces was found to be comparable to those detected in fingerprints developed by using a commercial black magnetic powder. The cost is lowered by more than 60%.     

Visualization of Latent Fingerprint Corrosion of Brass

Abstract:  Visualization of latent fingerprint deposits on metals by enhancing the fingerprint-induced corrosion is now an established technique. However, the corrosion mechanism itself is less well understood. Here, we describe the apparatus constructed to measure the spatial variation (Δ V ) in applied potential ( V ) over the surface of brass disks corroded by latent fingerprint deposits. Measurement of Δ V for potential of 1400 V has enabled visualization of fingerprint ridges and characteristics in terms of this potential difference with Δ V typically of a few volts. This visualization is consistent with the formation of a Schottky barrier at the brass-corrosion product junction. Measurement of the work function of the corroded brass of up to 4.87 ± 0.03 eV supports previous results that suggested that the corrosion product is composed of p-type copper oxides. A model for the galvanic corrosion of brass by ionic salts present in fingerprint deposits is proposed that is consistent with these experimental results.     

Refining Stable Oxygen and Hydrogen Isoscapes for the Identification of Human Remains in Mississippi,

Isoscape refinement is an essential component for accurately predicting region‐of‐origin in forensic investigations involving isotope analysis of unidentified human remains. Stable oxygen (δ¹⁸O) and hydrogen (δ²H) isotopes were measured from 57 tap water samples collected across Mississippi to model refined isoscapes for the state. A tap water conversion equation, δ¹⁸O_tw=1.64 δ¹⁸Op?31.35, was developed for the southeastern USA to test the prediction accuracy of the δ¹⁸O_tw isoscape using individuals with known residential histories. A local Mississippi resident (USAFA‐134) was assigned with 90% probability to the correct region‐of‐origin reported by the participant. Assignments for Georgia residents (USAFA‐118 and USAFA‐205) had variable results, predicting USAFA‐118 from Mississippi and USAFA‐205 as a nonlocal resident. Stable isotope values often overlap geographically and a multi‐isotope approach should be used when narrowing region(s)‐of‐origin(s). This study demonstrates the utility of refining isoscapes and the importance of tissue calibration in prediction assignments of human remains.     

Gas dispersal potential of bedding as a cause for sudden infant death

We assessed the gas dispersal potential of bedding articles used by 14 infants diagnosed with sudden unexpected infant death at autopsy. Of these cases, eight exhibited FiCO₂ values greater than 10% within 2.5 min, six of which were found prone and two supine. The results demonstrated that these eight beddings had a high rebreathing potential if they covered the babies’ faces. We did not, however, take into account in our model the large tissue stores of CO₂. As some bicarbonate pools will delay or suppress the increase of FiCO₂, the time–FiCO₂ graphs of this study are not true for living infants. This model, however, demonstrated the potential gas dispersal ability of bedding. The higher the FiCO₂ values, the more dangerous the situation for rebreathing infants. In addition, FiO₂ in the potential space around the model's face can be estimated mathematically using FiCO₂ values. The FiO₂ graph pattern for each bedding item corresponded roughly to the inverse of the FiCO₂ time course. The FiO₂ of the above eight cases decreased by 8.5% within 2.5 min. Recent studies using living infants placed prone to sleep reported that some babies exhibited larger decreases in FiO₂ than increases observed in FiCO₂. While the decrease of FiO₂ in our model is still theoretical, CO₂ accumulation and O₂ deprivation are closely related. If a striking O₂ deficiency occurs in a short period, babies can lose consciousness before an arousal response is evoked and all infants could be influenced by the poor gas dispersal of bedding; the main cause of sudden death in infancy would thus be asphyxia. When the bedding is soft, the potential for trapping CO₂ seems to be high; however, it is impossible to assess it by appearance alone. We sought to provide some objective indices for the assessment of respiratory compromise in relation to bedding using our model. When a baby is found unresponsive with his/her face covered with poor gas dispersal bedding, we should consider the possibility of asphyxia.     

HOMICIDE IN DETROIT The Role of Firearms

This study attempts to determine the role of firearms in accounting for the rising homicide rate of one city. Firearms were examined in relation to other weapons and subsequently firearm availability was examined in relation to other variables that could affect the rate of homicides. A majority of the increase in the homicide rate could be attributed to an increase in handgun murders. Firearm availability accounted for one-quarter of the rise in homicides.     

Perceived effects of concealed handgun ownership by private citizens among law enforcement officers in Texas

On January 1, 1996, a new law took effect in Texas granting certain state citizens the privilege to carry a concealed handgun on their person for the first time since 1871. As a result of this dramatic shift in state law, Texas is now among the growing number of states across the nation who have adopted similar statutory provisions in one form or another. While at least one empiricals study of citizen’s attitudes toward concealed handgun ownership was conducted prior to the law’s effective date, no similar efforts were undertakens to assess the beliefs, perceptions and attitudes of the state’s law enforcement officers about this important social policy. The present study was therefore undertaken in response to the lack of serious attention which the issue of concealed handgun ownership among private citizens has received as it directly relates to the law enforcement profession. Subjects for this study (N=327) were drawn from four Texas law enforcement agencies representing various organizational sizes and missions. While the responses of officers who participated in the study indicate optimism about the law’s potential to deter various types of crime, they also reflect a certain degree of concerns about concealed handgun ownership among private citizens especially as this policy directly relates to perceive inadequacies in statemandated requirements and issues affecting officer safety.     

Comparative analysis of 1-phenyl-2-propanone (P2P), an amphetamine-type stimulant precursor, using stable isotope ratio mass spectrometry: Presented in part as a poster at the 2nd meeting of the Joint European Stable Isotope User Meeting (JESIUM), Giens, France, September 2008

The isotope ratios of amphetamine type stimulants (ATS) depend as well on the precursor as the synthetic pathway. For clandestine production of amphetamine and methamphetamine, 1-phenyl-2-propanone (P2P, benzylmethylketone) is a commonly used precursor.Our aim was to determine the variation of the isotope ratios within precursor samples of one manufacturer and to compare seized samples of unknown sources to these values. δ¹³C_V-PDB, δ²H_V-SMOW and δ¹⁸O_V-SMOW isotope ratios were determined using elemental analysis (EA) and gas chromatography (GC) coupled to an isotope ratio mass spectrometer (IRMS). The comparison of all seized samples to the data of the samples of one manufacturer revealed considerable differences. The results show that IRMS provides a high potential in differentiating between precursors from different manufacturers for the clandestine production of ATS and identifying corresponding sources.     

Simple determination of carboxyhemoglobin by double wavelength spectrophotometry of absorbance difference and the comparison with gas chromatographic method

This paper describes the spectrophotometric determination of carboxyhemoglobin (CO-Hb) in blood on the basis of double wavelength spectrophotometry of absorbance difference. Absorbance measurements are made in the 500–600 nm region at a blood dilution of 100–200-fold. Blood is diluted with a solution containing Na₂S₂O₄ to provide two components of CO-Hb and deoxyhemoglobin (deoxy-Hb). Absorbance difference at the two wavelengths at which deoxy-Hb has the same absorbance reflects only the CO-Hb component because the opposite component is nulled out of the mixture. After measurement of the absorbance difference, the measuring solution is saturated with CO gas to make all Hb derivative CO-Hb and remeasured at the same wavelengths. The percent of CO-Hb is considered the absorbance difference ratio. Results obtained by the present method was in satisfactory agreement with gas chromatographic data in blood not containing methemoglobin (Met-Hb). Comparative experiments using the gas chromatographic method and the present method were performed with samples containing Met-Hb. However, while there is a deficiency in the gas chromatographic method when the samples contain Met-Hb, the results of the present method were in close agreement with theoretical values when samples are mixed with CO-Hb, O₂-Hb and Met-Hb. Advantages of this method are that it is simple and accurate, standard curve or equation for calculation and accurate dilution are not necessary.