The role of center of mass kinematics in predicting peak utilized coefficient of friction during walking

Slips frequently occur when the friction required between the foot and floor exceeds available surface slip resistance. To date, the ability to identify variables that predict an individual's friction needs during walking, or utilized coefficient of friction (COFU), remains limited. Understanding COFU in the context of pedestrian/walkway accidents is important as individuals who demonstrate higher COFU are at a greater risk of slipping. This study determined if whole body center of mass (CM) kinematics were predictive of peak COFU during walking. Ground reaction forces and kinematic data were recorded simultaneously as subjects walked. Stepwise regression analysis determined that the combination of the subject's CM-to-center-of-pressure angle and CM anterior (i.e., forward) velocity predicted 62% of the variance in peak COFU during weight acceptance (p < 0.001). The identified relationships between CM kinematics and peak COFU provide insight into how gait and individual anthropometric characteristics may increase risk for slip initiation.     

Estimation of stature from stride length while walking fast

Estimation of stature from various foot and shoe measurements with the help of statistical methods is well known. However, very little work has been reported on stature estimation from stride length. As the stride length may vary in different walking speeds, in the present paper, stride length of individuals were measured while walking fast on smooth substrate has been compared with the stride length in the normal pattern of walking. Although the formulae derived are different for faster pace, the range of error in estimation of stature remains almost the same.     

Differential decomposition patterns in charred versus un-charred remains

Although researchers have examined many aspects of fire modification, the rate and pattern of decomposition in charred remains have not been studied previously. This study utilized 48 domestic pigs, divided into 24 charred (head, neck, and limbs burned to Crow-Glassman level 1 and torso to level 2) and 24 un-charred pig carcasses. Decomposition of control carcasses was scored at 50 accumulated degree days (ADD) intervals, and charred carcasses were also observed and photographed at this time. A Charred Body Scale was subsequently created, and charred carcasses were scored retrospectively for the same ADD intervals. Analysis using a mixed-effect repeated measures model indicated that, while decomposition rate was not statistically different between the two groups (p = 0.2692), the charred remains initially displayed an ostensibly more advanced pattern. Body regions displaying significant charring decomposed at a faster rate (p < 0.001), while areas with very light levels of charring decomposed at a significantly slower rate (p < 0.001).     

Evaluation of the correlation between time corpses spent in in-ground graves and findings at exhumation

To determine how long pathological findings persist after burial and which factors play a role in decomposition of a corpse, we evaluated all bodies exhumed under the auspices of the Institute of Legal Medicine at the Hannover Medical School between 1978 and 1997. A total of 87 exhumations (54 men, 33 women) were performed in this period. The time bodies remained buried varied between 5 days and 16.8 years (mean 1.5 years, median 2.3 months). Fifty-six percent of the bodies were exhumed after at most 3 months, 10% remained buried for greater than 3 years. Pathomorphological changes of the soft tissues and the internal organs remained evident after several months, in some cases after several years of burial. Overall, it was possible to evaluate internal organs after 5 years of burial. Bodies became mostly decomposed after approximately 8 years at the earliest, although it was still possible to evaluate some soft tissue remnants after 16.8 years. In stepwise logistic regression, both the length of time the body was buried (p < 0.00005) and the time of year (p < 0.0019) clearly affected the rate of physical change. The variables of sex (p = 0.33), age (p = 0.61) and changes in the integrity of the body before burial (trauma, autopsy before burial; p = 0.15) did not influence the physical state of the body after exhumation. Our data show that much information may be gained from an exhumation even after significant time has passed since burial.     

Stature and sex estimate using foot and shoe dimensions

The aim of the study was to develop a formula to estimate the stature and sex of an individual using foot and shoe dimensions. To this aim the stature, right and left shoe sizes, and maximum and minimum feet length and width measurements of a target group of 569 individuals were taken. The group was composed of 294 males and 275 females. The highest correlation coefficient was found in length measurements. A notable difference between males and females existed with regard to both right and left foot and shoe length and width averages and shoe sizes (p < 0.001). Among the group, a significant correlation was found in regard to stature and right shoe length (r = 0.591, p < 0.001), with the correlation between stature and right foot length and stature and right shoe length being 0.579 (p < 0.001); as for the female group, there was a significant correlation between stature and right foot length and stature and right shoe length (r = 0.460, p < 0.001). Thus the regression formula obtained are as follows: for the right side: sex = 69.169 + 0.173 (maximum foot length) - 0.368 (maximum foot width) - 0.820 (shoe length) + 0.224 (shoe width) - 1.280 (shoe number). For the left side: sex = 69.551 + 0.276 (maximum foot length) - 0.504 (maximum foot width) - 0.739 (shoe length) + 0.344 (shoe width) - 1.360 (shoe number). In application of the formula, if sex is lower than 0.50, the shoe belongs to a male, if higher, then to female. The formula which was obtained in regression analysis in order to estimate the stature when the measurements of shoe and foot were known. For the right side, stature = 47.93 + 1.083 (maximum foot length) + 0.788 (shoe length) 1.813 (shoe number) (SEE:31.410). For the left side: stature = 47.33 + 1.139 (maximum foot length) + 0.593 (shoe length) x 1.924 (shoe number) (SEE:31.607). It was understood that foot and shoe sizes are a criteria to estimate the stature of a person that there was a strong relationship between foot and shoe length and width and that these can be used to aid estimation. It was found that in sex estimate, foot and shoe lengths are better in helping the estimate than width measurements, and that the use of shoe measurements rather than bare foot measurements are better to obtain meaningful results.     

Sociodemographic and diagnostic characteristics of homicidal and nonhomicidal sexual offenders

The aims of this study were to compare the prevalence of psychiatric disorders and "psychopathy" in homicidal and nonhomicidal sexual offenders and to investigate the specificity of previous studies on psychiatric morbidity of a sample of sexual murderers. Information from court reports of 166 homicidal and 56 nonhomicidal sex offenders was evaluated using standardized instruments (SCID-II, PCL-R) and classification systems (DSM-IV). Sexual murderers were diagnosed more often with a personality disorder (80.1% vs. 50%; p < 0.001), especially schizoid personality disorder (16.3% vs. 5.4%; p < 0.05), as well as with sexual sadism (36.7% vs. 8.9%; p < 0.001) and sexual dysfunctions (21.7% vs. 7.1%; p < 0.05). Additionally, they had more often used alcohol during the offense (63.2% vs. 41%; p < 0.05). The results indicate that sexual murderers have more and a greater variety of psychiatric disorders when compared to nonhomicidal sex offenders.     

回归法推断手印和足迹与身高和体重的关系

目的探讨身高、体重与足迹、手印长宽的关系。方法通过足迹、手印的捺印和测量,大量地收集样本足迹、手印与身高、体重等数据,借助SPSS数理统计软件,进行一元线性回归分析。结果分别建立了由左右足迹、手印全长、掌宽推算身高与体重的10个一元线性回归方程,并对依据各个指标分别推算结果的可靠性进行比较研究。结论本研究建立的回归方程可用于山东地区部分人群的身高与体重推算;依据足迹较依据手印推算身高体重结果更可靠;在左右两侧足迹、手印都可利用的情况下,推断身高时应优先选用右侧;推断体重时应优先选用左侧。     

Co-occurring Psychiatric and Substance Dependence Disorders as Predictors of Parolee Time to Rearrest

An estimated 500,000-plus people are on parole each year, many with serious co-occurring psychiatric and substance use disorders. Using cross sectional, self-report data this study examined the relationships between parolee time to rearrest, serious mental illnesses, and substance dependency (n = 1,121). Regression analyses indicated that after controlling for demographic and criminal justice variables, parolees with serious psychiatric and substance dependence disorders were rearrested faster than non-dually diagnosed parolees (p < .05). An explanation is that compared with parolees without dual diagnoses, parole violations by dually diagnosed parolees are detected and punished more quickly because of closer parole supervision.     

Estimation of stature from footprint and foot outline dimensions in Gujjars of North India

Estimation of individual's stature is an important parameter in forensic examinations. Examination of footprints provides important evidence in a crime scene investigation and helps in estimation of stature of a criminal. Analysis of bare footprints is often carried out in developing countries like India where the footprints are frequently recovered at the scene of crime. The present study attempts to reconstruct stature in a sample of 2080 bilateral footprints and foot outlines collected from 1040 adult male Gujjars of North India ranging in age from 18 to 30 years. Bilateral footprints and foot outlines of each individual were measured for ten and eight measurements, respectively. The results indicate that T-2 length (length of the footprint from heel to 2nd toe) and T-5 length in footprint and T-1 length, T-4 length and breadth at ball in foot outline show statistically significant bilateral asymmetry. Significant and positive correlation coefficients exist between stature and various measurements of footprint and foot outline (P<0.001 and 0.01) except toe 1-5 angle of declination which shows insignificant correlation coefficient. The highest correlation coefficients were shown by the toe length measurements (0.82-0.87) indicating a close relationship between the stature and these measurements. Regression analysis presents smaller mean errors (2.12-3.92cm) in estimation of stature than those of division factor method (3.29-4.66cm), thus, gives better reliability of estimate than the latter. The regression equations were also checked for their accuracy by comparing the actual stature with estimated stature.     

A Test of Three Methods for Estimating Stature from Immature Skeletal Remains Using Long Bone Lengths*

Abstract: In this study, the accuracy of three methods for stature estimation of children from long bone lengths was investigated. The sample utilized consists of nine identified immature skeletons (seven males and two females) of known cadaver length, aged between 1 and 14 years old. Results show that stature (cadaver length) is consistently underestimated by all three methods (from a minimum of 2.9 cm to a maximum of 19.3 cm). The femur/stature ratio provided the least accurate estimates of stature, and predictions were not significantly improved by the other two methods. Differences between true and estimated stature were also greatest when using the length of lower limb bones. Given that the study sample children grew in less than optimal environmental conditions, compared with the children that contributed to the development of the methods, they are stunted and have proportionally shorter legs. This suggests that stature estimation methods are not universally applicable and that environmental differences within a population (e.g., socioeconomic status differences) or differing levels of modernization and social and economic development between nations are an important source of variation in stature and body proportions of children. The fallibility of stature estimation methods, when they do not consider such variation, can be somewhat minimized if stature is estimated from the length of upper limb bones.     

A laboratory incubation method for determining the rate of microbiological degradation of skeletal muscle tissue in soil

A controlled laboratory experiment is described, in principle and practice, which can be used for the of determination the rate of tissue decomposition in soil. By way of example, an experiment was conducted to determine the effect of temperature (12 degrees, 22 degrees C) on the aerobic decomposition of skeletal muscle tissue (Organic Texel x Suffolk lamb (Ovis aries)) in a sandy loam soil. Measurements of decomposition processes included muscle tissue mass loss, microbial CO2 respiration, and muscle tissue carbon (C) and nitrogen (N). Muscle tissue mass loss at 22 degrees C always was greater than at 12 degrees C (p < 0.001). Microbial respiration was greater in samples incubated at 22 degrees C for the initial 21 days of burial (p < 0.01). All buried muscle tissue samples demonstrated changes in C and N content at the end of the experiment. A significant correlation (p < 0.001) was demonstrated between the loss of muscle tissue-derived C (Ct) and microbially-respired C (Cm) demonstrating CO2 respiration may be used to predict mass loss and hence biodegradation. In this experiment Q10 (12 degrees C-22 degrees C) = 2.0. This method is recommended as a useful tool in determing the effect of environmental variables on the rate of decomposition of various tissues and associated materials.     

Population drug use in Australia: a wastewater analysis

Accurate information on drug use in communities is essential if health, social and economic harms associated with illicit drug use are to be addressed efficiently. In most countries population drug use is estimated indirectly via surveys, medical presentations and police and custom seizures. All of these methods have at least some problems due to bias, small samples and/or long time delays between collecting the information and analysing the results. Recently the direct quantification of drug residues in wastewater has shown promise as a means of monitoring drug use in defined geographical areas. In this study we measured 3,4-methylenedioxymethamphetamine (MDMA), methamphetamine and benzoylecgonine in sewage inflows in metropolitan and regional areas of Australia and compared these data with published European data. Cocaine use was small compared to European cities (p<0.001) but was compensated for by much greater consumption of methamphetamine (p<0.001) and MDMA (p<0.05). MDMA was more popular in regional areas (p<0.05) whereas methamphetamine and cocaine were mainly consumed in the city (p<0.05). Greater than 5-fold increases in MDMA use were detected on weekends (p<0.001). This approach has the potential to improve our understanding of drug use in populations and should be further developed to improve prevention and treatment programs.     

Kinematics of four methods of stabbing: a preliminary study

Despite considerable research and development into stab-resistant clothing, no data exists which provides valid data for knife-body contact speeds which may be used to ensure that an appropriate and standard protection level is provided. Such data can only be obtained by a quantitative kinematic analysis of the stabbing movement. Two-dimensional video techniques (50 Hz) were used to record images of subjects (n = 10) performing each of four stabbing actions; Long Over (LO), Long Under (LU), Short Over (SO), Short Under (SU). Images were digitised from a minimum of ten frames pre-, to at least six frames post-blade entry. A two-way analysis of variance applied to selected kinematic parameters revealed significantly higher (P < 0.01) blade entry speeds for LO and LU as compared to SO and SU, respectively. This was due to the extra distance over which knife speed could be increased in the former conditions. Significantly greater shoulder joint angular velocities were found for LU and SU conditions, whilst for the elbow joint, conditions LO and SO were significantly greater (P = 0.000008). This suggests that the entry speeds during LO and SO are derived from a greater contribution from elbow extensor muscles, whilst those for LU and SU are derived from a greater contribution from the shoulder flexors. It was concluded that two separate kinematic strategies were employed by subjects, and that the maximum speed which may be generated during stabbing is influenced by the manner in which the knife is held.     

大鼠尸僵发展过程中肌节长度的变化及其长度测定

目的观察大鼠尸僵发展过程中肌节形态、肌节长度的变化。方法 2 1只大鼠分为 3组 ,每组大鼠分别于死后立即和死后 2h、 4h、 6h、 8h、 12h、 2 4h取材 ,扫描电镜下观察大鼠死后不同时间的肌节形态 ,同时测定肌节长度。结果死后立即取材标本肌原纤维松散 ,纤维间有一定的间隙 ;死后 2h ,肌原纤维间界限模糊 ,出现周期性横纹 ;死后 4h、 6h横纹清晰 ;死后 12h肌原纤维断裂 ,仍可见横纹 ;死后 2 4h肌原纤维断裂、融合。各组大鼠肌节长度与同组立即取材时比较 ,死后 2h、 4h、 6h、 8h均显著变短 (P值均小于 0 0 0 1) ,其中死后 4～ 6h最短 ;死后12h均无显著性差异 (P值均大于 0 0 5 ) ;死后 2 4h ,组 1、组 3无显著性差异 (P值均大于 0 0 5 ) ,组 2差异显著(P值为 0 0 0 7)。结论用扫描电镜测定肌节长度 ,发现肌节长度随尸僵经过时间的延长而发生变化     

Travel, time zones, and sudden cardiac death. Emporiatric pathology

In an 11-year retrospective study of coroner's autopsies on the Hawaiian island of Kauai, it was found that an unusual and apparently unique subset of travelers died suddenly. Death was caused by coronary arteriosclerosis, was characterized by acute coronary changes, and occurred in a group younger than the usual age for sudden cardiac death. Visitors with two-vessel disease had an incidence of sudden death nearly four times that of Kauaians (p less than 0.02), with a ninefold increase of coronary thrombosis (p less than 0.001), a sixfold prevalence of old myocardial infarcts (p less than 0.001), and three times the prevalence of cardiomegaly (p less than 0.001). The circadian pattern of these deaths was different from that previously described in acute myocardial infarction or sudden death, with the number of incidents rising steadily through the day in contrast to the morning peak described in previously published series. The syndrome was expressed in decedents with two-vessel coronary disease either with acute coronary artery lesions--thrombosis, hemorrhage in a plaque, or ruptured coronary artery--or no lesions, presumably spasm. Underlying chronic processes included enlarged heart or old myocardial infarct, which both occurred with a significantly greater incidence in travelers than in local residents, and in a totally different pattern from that occurring in subjects with three-vessel disease. It is postulated that the syndrome is caused by stress related to travel and time zone changes.     

Fatal falls from a height: two case studies

Two case studies are presented involving fatal falls of adult females from a height. One involved a launch at low speed from a balcony, and one involved a launch at high speed from the top of a cliff. Crime scene evidence obtained on the balcony itself provided a strong indication of homicide, but subsequent investigation showed that the fall was accidental. No crime scene evidence was obtained for the cliff fall since the fall initially appeared to be just another suicide from a popular suicide spot. Subsequent investigations indicated homicide based on measurements of cliff height, horizontal distance to the impact, and available runup distance, plus measurements of possible run, jump, and throw speeds. It was found that a female weighing 61 kg (134 lb) can be thrown at speeds up to 4.85 m/s by a strong male, more than enough to account for the estimated launch speed (4.5 m/s). Given the available 4.0 m runup distance, it was found that women of better than average rather than elite athletic ability can dive at speeds of about 3.5 m/s or jump feet first at speeds of about 4.0 m/s, both being less than the estimated launch speed. The decedent had no athletic ability and landed head first after falling through a height of 29 m.     

Predicting the position of the source of blood stains for angled impacts

Droplets of pig's blood were dropped onto paper at different angles to the horizontal to produce blood stains. Impact velocities varied from 1.82 to 5.76 m/sec, drop size from 3.7 to 5.0 mm in diameter, and the surface sloped at angles between 22.7 degrees and 90 degrees to the horizontal. From the data a single equation relating stain size to drop size and velocity for all impact angles was produced; ab = 111.74 (Re(1/2)We(1/4))(0.75)D(o)D(o) + 0.00084 with R(2) = 0.88, where a is the stain width, b the stain length, Re the Reynolds number, and We the Weber number. A second equation related the number of spines, N, to drop size, velocity, and surface slope for all impact angles as N = 0.76 We(0.5) sin(3)theta with R(2) = 0.9, where theta is the impact angle. Combining these equations the impact velocity can be determined and hence the position of the stain's source.     

依据手足印推算身高体重的可行性研究

目的探讨身高、体重与足迹、手印长宽的关系,有助于利用犯罪现场的手印、足迹推断遗留人的身高与体重。方法通过足迹、手印的捺印和测量,大量地收集样本足迹、手印与身高、体重等数据,借助SPSS数理统计软件,进行一元线性回归分析。结果分别建立了由左右足迹、手印全长、掌宽推算身高与体重的十个一元线性回归方程,并对依据左、右侧指标分别推算结果的可靠性进行比较研究。结论可利用回归法由足迹、手印来推算身高、体重。在左右两侧足迹、手印都可利用的情况下,推断身高时应优先选用右侧;推断体重时应优先选用左侧。