Fingermark ridge drift: Influencing factors of a not-so-rare aging phenomenon.

Fingermark ridge drift is a random modification of (aged) fingermark patterns at a ridge scale. This phenomenon was previously proven to alter key elements used for identifications, such as the appearance of minutiae. Little is currently reported on the underlying factors contributing to its occurrence. The present study was designed to investigate further the variables of a previous study by including a total of 768 fingermarks from a male and female, two substrates (glazed ceramic tile and plastic), two distinct color powder developers (carbon black and titanium dioxide), three indoor lighting conditions (direct natural light, shade, and darkness), and two secretion types (sebaceous- and eccrine-rich). Fingermarks were aged for 2-72 days, powdered, photographed, and drift detected by three independent observers. All aged fingermarks (672) were compared relative to fresh fingermarks (96), and ridge drift was observed in 42 of 672 (6%) fingermarks, while 168 (25%) were reported as indeterminate results. While ridge drift was detected in multiple fingermarks across all independent variables, statistical analysis using a multinomial logistics model showed that only powder type, secretion type, and the substrate indicated a significant correlation with increased incidences of this phenomenon. There was no significant correlation with the donor, time since deposition, or the environmental lighting conditions used. The highest incidence occurred when carbon black powder was used on a plastic substrate (>10%). The average observation of ridge drift is 6% of samples supporting that this phenomenon is not a rare event, particularly considering the conservative analysis approach implemented.

Evaluation of latent fingermark color contrast as aging parameter under different environmental conditions: A preliminary study.

This research expands previous studies in which color contrast between ridges and furrows of powder-enhanced latent fingermarks was explored as a possible aging parameter. The main goal is to test the sensitivity of the technique across a predetermined set of factors. In this case, experiment factors have included two donors who deposited sebaceous- and eccrine-rich fingermarks onto ceramic tile and polystyrene plastic. These were developed with either black carbon or titanium dioxide powder (TiO2 ) over eight time periods (0-72 days) and aged under three light conditions (direct light, shade, and darkness). The mean intensity (MI) and intensity amplitude (IA) metrics of color were collected from each image for statistical analyses. Results show that color contrast is affected significantly by substrate, secretion, and powder types, with an interaction effect between the substrate and powder type on both MI and IA metrics. The degree of light exposure did not have a noticeable impact on distinguishing aging patterns of fingermarks by neither powder methods. Different aging patterns were detected between sebaceous-rich and their eccrine-rich counterparts for all light conditions using regression analysis. All eccrine-rich fingermarks exhibited little (or minimal) change in IA over time, whereas sebaceous-rich samples showed varied patterns, from significant decreases to slight increases. These findings confirm and expand previous observations on the potential use of MI and IA as metrics to study latent fingermark degradation patterns that could eventually be used to estimate the age of a fingermark.

Abusive head trauma among children in Alaska: a population-based assessment.

BACKGROUND: Serious physical abuse resulting in a traumatic brain injury (TBI) has been implicated as an underreported cause of infant mortality. Nearly 80% of all abusive head trauma (AHT) occurs among children <2 years of age, with infants experiencing an incidence nearly 8 times that of 2-year olds. OBJECTIVE: This study describes the validation of the CDC Pediatric Abusive Head Trauma (PAHT) definitions when applied to a multi-source database at the state level and provides a robust annual incidence estimate of AHT among children <2 years of age in Alaska. DESIGN: AHT cases among children residing in Alaska during 2005-2010 were identified by applying the PAHT coding schema to a multi-source database which included vital death records, the Violent Death Reporting System (AK-VDRS), the Maternal Infant Mortality Review - Child Death Review (MIMR-CDR), the Alaska Trauma Registry (ATR), the inpatient Hospital Discharge Database (HDD) and Medicaid claims. Using these data, we calculated statewide AHT annual incidence rates. RESULTS: The databases with the highest case capture rates were the ATR and Medicaid systems, both at 51%, followed by HDD at 38%. Combined, the ATR, HDD and Medicaid systems captured 91% of all AHT cases. The linkage and use of the PAHT definitions yielded an estimated sensitivity of 91% and specificity of 98%. During the study period, we detected an annual average incidence of 34.4 cases per 100,000 children aged <2 years (95% CI 25.1, 46.1) and a case fatality proportion of 22% (10/45). Among the AHT cases, 82% were infants. Significant differences (p < 0.05) in AHT were noted by age and race, but not by sex. CONCLUSIONS: In Alaska, applying the CDC PAHT definition to the multi-source database enabled us to capture 49% more AHT cases than any of the individual database used in this analysis alone.

Effect of piperonyl butoxide on permethrin toxicity in the amphipod Hyalella azteca.

Piperonyl butoxide (PBO) is a synergist of pyrethroid pesticides found in many products for structural pest control, mosquito control, and home and garden uses. Because both PBO and pyrethroid residues potentially co-occur in urban creeks, this study determined if environmental levels of PBO were capable of synergizing pyrethroids in the environment. Three types of toxicity tests were conducted with the amphipod Hyalella azteca to determine the minimum PBO concentration required to increase toxicity of the pyrethroid permethrin: Sediment was spiked with permethrin only; permethrin and overlying water spiked with PBO; and permethrin, PBO, and overlying water spiked with PBO. In tests with PBO added to both water and sediment, PBO concentrations of 2.3 microg/L in water and 12.5 microg/kg in sediment reduced the permethrin median lethal concentration (LC50) nearly 50% to 7.3 mg/kg organic carbon (OC). Higher concentrations of PBO increased permethrin toxicity up to sevenfold. In exposures with PBO in water alone, 11.3 microg/L was required to increase permethrin toxicity. Urban creek sediments from California and Tennessee, USA, had PBO concentrations in the low microg/kg range; only one water sample was above the detection limit of 0.05 microg/L. Wetlands in northern California also were sampled after application of pyrethrins and PBO for mosquito abatement. Sediment and water PBO concentrations within 12 h of abatement spraying peaked at 3.27 microg/kg and 0.08 microg/L, respectively. These results suggest that environmental PBO concentrations rarely, if ever, reach concentrations needed to increase pyrethroid toxicity to sensitive organisms, though available data on environmental levels are very limited, and additional data are needed to assess definitively the risk.