Using ninhydrin to detect gravesoil

Some death scene investigations commence without knowledge of the location of the body and/or decomposition site. In these cases, it is necessary to locate the remains or the site where the body decomposed prior to movement. We hypothesized that the burial of a mammalian cadaver will result in the release of ninhydrin reactive nitrogen (NRN) into associated soil and that this reaction might have potential as a tool for the identification of clandestine graves. Juvenile rat (Rattus rattus) cadavers were buried in three contrasting soil types in Australian tropical savanna ecosystems and allowed to decompose over a period of 28 days. Soils were sequentially harvested and analyzed for NRN. Cadaver burial resulted in an approximate doubling (mean = 1.7 +/- 0.1) in the concentration of soil NRN. This reaction has great potential to be used as a presumptive test for gravesoil and this use might be greatly enhanced following more detailed research.     

Using STR analysis to detect human DNA from exploded pipe bomb devices

This study investigated the possibility of recovering a bomb assembler's DNA from an exploded pipe bomb device. Metal and polyvinyl chloride (PVC) pipes were examined to determine if one surface type would allow better DNA recovery than the other. Ten subjects each handled components of one metal and one PVC pipe bomb. The bombs were exploded, the fragments were collected and swabbed using the double swab technique, and the samples were extracted, quantified, amplified, and genotyped using polymerase chain reaction/short tandem repeat (PCR/STR). Of the 20 bombs handled by the subjects, four bombs gave reportable results that matched the subject's known DNA profiles. An additional eight profiles, also matching the subject's known DNA profiles, were generated but were below the reportable threshold. There was no difference in the success rate of obtaining DNA profiles related to the use of either PVC or metal in the manufacture of the pipe bomb. The variables that appeared to have the greatest influence on the success of generating a DNA profile were the amount of fragmentation and subsequent recovery of the bomb fragments. It is suspected that successful DNA profiling could also be dependent upon the bomb assembler's propensity to slough skin cells on objects they handled.     

Using brain MERMER testing to detect knowledge despite efforts to conceal

This experiment examined the accuracy and reliability of the memory and encoding related multifaceted electroencephalographic response (MERMER) technique for detecting information related to events subjects have experienced, despite subjects' efforts to conceal that knowledge. Information obtained through interviews was used to develop stimulus sets consisting of words and phrases presented to subjects visually by computer. Sets were composed of three types of stimuli: life experience-related (Probes), stimuli the subject was asked to memorize and respond to (Targets), and irrelevant information (Irrelevants). Each set of stimuli was tested on two individuals: (1) one individual who had participated in the event in question--and thus had the relevant information stored in his/her brain, and (2) one who had not. Six subjects were tested. Electrical brain responses to the stimuli were recorded non-invasively from the scalp and analyzed. MERMERs, (memory and encoding related multifaceted electroencephalographic responses), of which the P300 is a sub-component, were used to determine whether the subject had the relevant information stored in his brain (information present) or not (information absent), thus indicating whether or not each subject had participated in the real-life event in question. Bootstrapping was used to analyze and compare the responses to the three types of stimuli. As predicted, MERMERs were elicited by Probe stimuli only in the subjects who had participated in the investigated event, by Target stimuli in all subjects, and in no case by Irrelevant stimuli. For each of the six subjects, brain MERMER testing correctly determined whether the subject had participated in and consequently knew about the event in question (information present) or had not participated (information absent). The statistical confidence for this determination was 99.9% in five cases and 90.0% in one case. The article concludes with a discussion of areas of future research and the potential for using this new technology as an investigative tool in criminal cases.     

Using indirect questions to detect intimate partner violence: the SAFE-T questionnaire

A screening instrument for detecting intimate partner violence (IPV) was developed using indirect questions. The authors identified 5 of 18 items studied that clearly distinguished victims of IPV from a random group of health conference attendees with a sensitivity of 85% and a specificity of 87%. This 5-item instrument (SAFE-T) was then tested on 435 women presenting to three emergency departments and the results compared to a direct question regarding current abuse. The SAFE-T questions detected only 54% of the women who admitted being abused and correctly classified 81% of the women who said they were not victims. The 1-year prevalence of IPV in this sample of women presenting to an emergency department was 11.6%. The authors conclude that indirect questioning of women appears to be more effective at ruling out IPV in an emergency department population and may be less useful for women "early" in an abusive relationship.     

Failure to detect elevated levels of carboxyhemoglobin in infants dying from SIDS

Carboxyhemoglobin (COHb) levels were determined in stored blood samples from 91 infants diagnosed to have died from the sudden infant death syndrome (SIDS) (0.59+/-0.41%, excluding one outlying value of 10.83%); 48 age-matched controls (0.53+/-0.38%); and three individuals who died from fire related causes (41+/-20%). No statistical differences in COHb levels were detected between blood from SIDS and control infants (p = 0.43).     

微波消解-扫描电镜联用检测脏器内硅藻

目的介绍一种微波消解-扫描电镜联用检测脏器内硅藻的新方法。方法大白兔30只,随机分为生前溺死组（n=15）和死后溺尸组（n=15）。提取兔肺、肝、肾、股骨骨髓和现场珠江水样,采用建立的微波消解-扫描电镜联用法检测脏器组织和水样中的硅藻,并与硝酸乙醇消解-扫描电镜联用的方法进行比较。结果生前溺死组的兔肺、肝、肾、股骨骨髓组织中大多数观测到与现场珠江水样一致的硅藻,微波消解-扫描电镜联用法检测脏器内硅藻的平均含量分别为：2505.2个/2g肺,18.7个/10g肝,6.5个/10g肾,6.3个/0.5g骨髓;肺与肝、肾、骨髓检出硅藻的阳性比例为86.7%,脏器硅藻检出含量和硅藻检验阳性比例均明显高于硝酸乙醇消解-扫描电镜联用法所测值。死后溺尸组的兔脏器组织均未观测到硅藻。结论微波消解-扫描电镜联用法检测脏器内硅藻,高效、安全、环保,硅藻检验灵敏度高,降低了劳动强度,提高了定性定量分析准确度,且能有效避免污染,在法医学溺死鉴定中具有良好的应用价值。     

A rapid method to detect dried saliva stains swabbed from human skin using fluorescence spectroscopy

Saliva on skin is important in forensic trace evidence. If areas where saliva is present can be outlined, this may lead to DNA analysis and identification. This study describes a rapid and non-destructive method to detect dried saliva on the surface of the skin by fluorescence spectroscopy. Eighty-two volunteers deposited samples of their own saliva on the skin of their ventral forearm. A control sample of water was deposited at three different sites on the contralateral arm. Saliva and water control were then allowed to air-dry. Swab samples were taken from dried saliva and control sites and were dissolved in 0.1M KCl solution. Emission spectra were obtained from the solution and were characterized by a principal maximum at 345-355nm with excitation at 282nm. The fluorescence emission intensity was greater than background readings obtained from the control swab site in 80 of 82 volunteers (approximately 97.6%). The fluorescence profile of saliva samples were similar to those obtained from aqueous samples of pure amylase and tryptophan, an endogenous fluorophore in alpha-amylase. The presence of an emission peak at 345-355nm with excitation at 282nm could provide a strong presumptive indication of saliva deposition.     

Interoperability from Electronic Commerce to Litigation Using XML Rules

We used the XML Rule system, earlier described in 7, 14, and16, to simulate litigation arising from electronic commercein a purchase order situation. This work is distinguished byusing XML documents that comply with standards, especially thosefrom OASIS.     

The use of crossover immunoelectrophoresis to detect human blood protein in soil from an ambush scene in Kosovo

This study examines the survivability of human blood proteins in soils from a year and a half old ambush scene in Kosovo. A total of 72 soil samples were collected, a number of which were directly associated with bone fragments or bullet projectiles. The samples were examined using crossover immunoelectrophoresis (CIEP) to determine the presence of blood protein and species affiliation. Human blood proteins were identified in 44 of the 72 samples (61%) with the majority of the positive observations (29 of 44) found 0.0-4.5 cm below ground surface (65%). Chi-squared and two-sample difference of proportions tests confirmed significant differences between samples with and without associated physical evidence and the presence and depth of human blood proteins. While DNA has largely replaced immunological analysis in forensic analyses, our results suggest that in particular situations, CIEP may still be a valuable tool in criminology.     

Using FastID to analyze complex SNP mixtures from indoor dust

Forensically relevant single nucleotide polymorphisms (SNPs) can provide valuable supplemental information to short tandem repeats (STRs) for investigative leads, and genotyping can now be streamlined using massively parallel sequencing (MPS). Dust is an attractive evidence source, as it accumulates on undisturbed surfaces, often is overlooked by perpetrators, and contains sufficient human DNA for analysis. To assess whether SNPs genotyped from indoor dust using MPS could be used to detect known household occupants, 13 households were recruited and provided buccal samples from each occupant and dust from five predefined indoor locations. Thermo Fisher Scientific Precision ID Identity and Ancestry Panels were utilized for SNP genotyping, and sequencing was completed using Illumina^® chemistry. FastID, a software developed to permit mixture analysis and identity searching, was used to assess whether known occupants could be detected from associated household dust samples. A modified “subtraction” method was also used in FastID to estimate the percentage of alleles in each dust sample contributed by known and unknown occupants. On average, 72% of autosomal SNPs were recovered from dust samples. When using FastID, (a) 93% of known occupants were detected in at least one indoor dust sample and could not be excluded as contributors to the mixture, and (b) non-contributor alleles were detected in 54% of dust samples (29 ± 11 alleles per dust sample). Overall, this study highlights the potential of analyzing human DNA present in indoor dust to detect known household occupants, which could be valuable for investigative leads.     

Using accumulated degree-days to estimate the postmortem interval from decomposed human remains

Forensic anthropologists often rely on the state of decomposition to estimate the postmortem interval (PMI) in a human remains case. The state of decomposition can provide much information about the PMI, especially when decomposition is treated as a semi-continuous variable and used in conjunction with accumulated-degree-days (ADD). This preliminary study demonstrates a supplemental method of determining the PMI based on scoring decomposition using a point-based system and taking into account temperatures in which the remains were exposed. This project was designed to examine the ways that forensic anthropologists could improve their PMI estimates based on decomposition by using a more quantitative approach. A total of 68 human remains cases with a known date of death were scored for decomposition and a regression equation was calculated to predict ADD from decomposition score. ADD accounts for approximately 80% of the variation in decomposition. This study indicates that decomposition is best modeled as dependent on accumulated temperature, not just time.     

The verdict is in: how did they decide? Using drivers’ self-reported data to understand officers’ decision making during traffic stop encounters

ABSTRACT

In the United States, traffic stop is the most common form of police-citizen encounter, and for many citizens, it is the only way they will ever interact with the police. The frequency of traffic stop encounters has therefore attracted a significant research interest. In the past several years, researchers have attempted to explain the dynamics of these interactions, with the hope to change attitudes and influence policy formation. To supplement the efforts of previous researchers, the current effort analyzed self-reported data from citizens to understand police decision making at three decision points during traffic stop encounters. Specifically, the present study aims to answer three questions: what variables predict whether an officer will let a citizen go without doing anything or decide to do something? If the officer decides to do something, what influences the officer’s decision to choose an outcome over others? What are the drivers of use of force in traffic stop encounters? Results from the regression models suggest that reasons for the stop, verbal assault, officer and suspect characteristics are important predictors of police decision making behavior during traffic stop interaction. The findings have serious implications for developing better police-citizen relationships as well as improving public attitudes toward the local police.     

运用市场机制配置资源是从源头上防治腐败的有效途径

通过改革和制度创新,可以最大限度地将行政机关可自由支配的权力加以约束,从而消除腐败产生的客观基础,减少腐败机会。具体而言,对于可以由市场自行调节的领域,政府应主动退出,把官员掌握的分配稀缺资源的权力降到最低限度,要最大限度地对行使这种权力的随意性加以削减。     

以社会主义核心价值体系引导网络政治参与

网络政治参与的快速发展使社会管理面临着巨大的挑战,如何使网络政治参与走上健康、积极有序的可持续发展轨道,是一个急需研究和解决的重大问题。网络政治参与需要内在文化的引领,而社会主义核心价值体系是引导网络政治参与的内在精神之魂。     

Using tibia fragments from South Africans of European descent to estimate maximum tibia length and stature

Intact long limb bones have been used in the derivation of regression equations for stature assessment in different population groups. Since intact long bones are not always present for analyses in forensic cases, it has become necessary to derive regression equations for the estimation of stature from the fragments of these bones which are obtained in forensic and archaeological cases. Regression equations have been derived for stature estimation from fragments of the tibia. Since these equations are population specific, it was the aim of this study to derive similar equations for estimation of stature and maximum tibia length from measurements of different fragments of tibia of South Africans of European descent. Analyses were based on a sample of 50 male and 50 female complete skeletons of adult South Africans of European descent. Total skeletal height for the individual skeletons was measured using the Fully's (anatomical) method. Six variables were measured on the tibia which included the medial tibial condyle lengths and breadths, lateral tibial condyle lengths and breadths, proximal breadth and distal breadth. Univariate and multivariate regression equations were formulated for estimation of total skeletal height (and subsequent estimation of living stature) and maximum tibial length from measurements of the tibia. The standard errors of estimate for the equations were higher than those obtained for intact long bones which when present in forensic cases should be used for stature estimation. In the absence of intact long bones, the equations derived from the present study can provide a reliable estimate of skeletal height and living stature.     

Comparing the Scoring of Human Decomposition from Digital Images to Scoring Using On‐site Observations

When in forensic casework or empirical research in‐person assessment of human decomposition is not possible, the sensible substitution is color photographic images. To date, no research has confirmed the utility of color photographic images as a proxy for in situ observation of the level of decomposition. Sixteen observers scored photographs of 13 human cadavers in varying decomposition stages (PMI 2–186 days) using the Total Body Score system (total n = 929 observations). The on‐site TBS was compared with recorded observations from digital color images using a paired samples t‐test. The average difference between on‐site and photographic observations was ?0.20 (t = ?1.679, df = 928, p = 0.094). Individually, only two observers, both students with <1 year of experience, demonstrated TBS statistically significantly different than the on‐site value, suggesting that with experience, observations of human decomposition based on digital images can be substituted for assessments based on observation of the corpse in situ , when necessary.     

使用危险化学品实施放火案件的物证检验1例

随着科技的发展,分析仪器在刑事技术领域的应用越来越广泛,有时往往会忽视对传统化学分析方法的应用。作为检验无机粉末的常用仪器,扫描电镜/能谱仪(SEM/EDS)和X射线衍射仪(XRD)受检出限的影响,无法准确分析样品中的低含量组分。本文在一起危险化学品放火案件检验中,为确定样品中含S元素的物质种类,利用化学分析法对其进行沉淀富集,再使用SEM/EDS和XRD检验,确认其中含有KMnO4和KHSO4,推测嫌疑人使用KMnO4和浓H2SO4等危险化学品实施放火,这在日常工作中比较罕见。通过总结相关工作经验,可为类似案事件的预防、物证提取和检验提供新的思路。     

The Cohort-Size Sample-Size Conundrum: An Empirical Analysis and Assessment Using Homicide Arrest Data from 1960 to 1999

A number of studies use the Age-Period-Cohort Characteristic (APCC) model to address the impact of cohort related factors on the age distribution of homicide offending. Several of these studies treat birth cohorts as spanning several years, an operationalization that most closely matches tenets of cohort theory, yet sharply reduces the number of observations available for analysis. Other studies define birth cohorts as those born within a single year, an operationalization that is theoretically problematic, but provides many more observations for analysis. We address the sample size problem by applying a time-series-cross-section model (panel model) with age-period-specific homicide arrest data from the United States for each year from 1960 to 1999, while operationalizing cohorts as five-year birth cohorts. Our panel model produces results that are very similar to those obtained from traditional multiyear APCC models. Substantively, the results provide a replication of work showing the importance of relative cohort size and cohort variations in family structure for explaining variations in age-period-specific homicide rates. The additional observations provided by our approach allow us to examine these relationships over time, and we find substantively important changes. The year-by-year estimates of the age distribution of homicide offending help us to examine the model during the epidemic of youth homicide.     

Using Spaced Learning Principles to Translate Knowledge into Behavior: Evidence from Investigative Interviews of Alleged Child Abuse Victims

The present study assessed the progress of 13 investigative interviewers (child protection workers and police officers) before, during, and after an intensive training program (n = 132 interviews). Training began with a 2-day workshop covering the principles of child development and child-friendly interviewing. Interviewers then submitted interviews on a bi-weekly basis to which they received written and verbal feedback over an 8-month period. A refresher session took place two months into training. Interestingly, improvements were observed only after the refresher session. Interviews conducted post-refresher training contained proportionally more open-ended questions, more child details in response to open-ended questions, and proportionally fewer closed questions than interviews conducted prior to training and in the first half of the training program. The need for ‘spaced learning’ may underlie why so many training programs have had little effect on practice.