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351.
Stable carbon isotope analysis has proven utility for reconstructing dietary information in humans in past populations. The usefulness of stable carbon for forensic geolocation has been little investigated, largely because of the globalization of the human diet seemingly rendering it inconsequential. This study queried this assumption at a country-wide level on a known sample group. Stable carbon isotope values were obtained from human enamel with known biographical and geographical information to determine whether stable carbon, when paired with stable oxygen isotope values, could differentiate Canadians from non-Canadians. Samples originating outside of Canada were separated into three regions, and a linear discriminant analysis was used to generate discriminant functions that best separate the regions according to the stable carbon and oxygen isotope values. The results revealed two functions, where the first function explained 92.1% and the second 7.9% of the variance. Although some overlap in stable carbon and oxygen values was observed for individuals from both the United States and Canada, differences were observed between those from Canada and other geographical regions. This study demonstrated that pairing the dietary isotope carbon with the geolocator stable oxygen isotope, produced an interesting separation geographically, one that might well be helpful when attempting a geolocation query on unknown human remains. 相似文献
352.
Alex Almeida Chedid BSc Larissa Silva Azevedo PhD Ayla Roberta Borges da Silva Galaço PhD Thiago Rui Casagrande BSc Osvaldo Antonio Serra PhD Marcelo Firmino de Oliveira PhD 《Journal of forensic sciences》2023,68(3):780-789
Currently, SEM-EDS is used to detect gunshot residue (GSR) from the presence of Ba, Pb, and Sb in the sample. However, the development of new nontoxic ammunition (NTA) has prevented conventional metals from being found. In this work, we aim to determine the presence of an inorganic luminescent chemical marker based on rare earth in gunshot residues using the technique of squarewave voltammetry (SWV). After firing, the luminescent complex [(Eu2Zr)(btc)3(Hbtc)0.5.6H2O], which is used as a chemical marker, can be detected under a UV lamp. An aqueous solution with 0.1 mol L−1 KCl as supporting electrolyte can be easily collected on carbon paste electrode surfaces for SWV analysis A = 100 mV, f = 10 Hz, and step potential of 5 mV are required. The luminescent marker incorporated into the carbon paste electrode showed two anodic peak currents in the region of 0.4 V (vs Ag/AgCl) and at 0.75 V (vs Ag/AgCl) and also a cathodic one in 0.4 V (vs Ag/AgCl). SEM-EDS was able to analyze the same voltammetric results for conventional and nontoxic ammunition containing the luminescent marker. Therefore, voltammetry and SEM-EDS are valid for detecting the new residue marker in GSR. Despite this, the electrochemical method is still more advantageous because of its low cost and lack of expensive equipment and supplies in forensic laboratories. 相似文献
353.
Dimple Bhatia MSc Chongtham Nimi MSc Sweety Sharma PhD Abhilash Kumar Das MSc Rajinder Singh PhD 《Journal of forensic sciences》2023,68(6):1982-1990
Sealing wax is used for maintaining the integrity and authenticity of a document or physical evidence. Any tampering with the seal calls into question the overall integrity and authenticity of the tangible evidence or document. In these circumstances, determining the authenticity of the sealing material (physical and chemical) becomes imperative. In this study, ATR-FTIR spectroscopy supported by chemometrics has been used to differentiate sealing wax samples belonging to 12 different brands available across India. All the samples were first melted, cooled, and then analyzed using ATR-FTIR spectroscopy in the mid-infrared region (4000–600 cm−1). The obtained spectra were first examined visually for the presence of different functional groups. Principal component analysis (PCA) and principal component analysis-linear discriminant analysis (PCA-LDA) were employed to analyze the sample clustering patterns and to categorize them into their respective groups, respectively. For classification, a PCA-LDA training model was applied, and it demonstrated 95.83% accuracy. The validation test resulted in an accuracy of 83.33%. PCA-LDA model offered 100% accurate prediction for samples on various substrates, including cloth, cardboard, and paper. A blind study was also performed using five unknown samples, which were accurately classified into their respective groups. PCA-LDA model will be helpful in providing investigative leads by linking a questioned sealing wax sample with its respective group. 相似文献
354.
Gail Cooper PhD 《Journal of forensic sciences》2023,68(5):1675-1685
Forensic toxicology laboratories are navigating a period of time with increasing drug overdose deaths, an opioid epidemic, the impact of the COVID-19 pandemic, and the illicit drug market flooded with novel psychoactive substances. In New York City, the Department of Forensic Toxicology has experienced a 56% increase in postmortem casework in the past decade with fentanyl detected in 80% of all overdose deaths. Over a period of 2.5 years, 15,638 postmortem cases were tested for the presence of fentanyl and fentanyl analogs using liquid-chromatography tandem mass spectrometry (LCMSMS). Fentanyl was detected in approximately one third of cases and of these 4447 cases with femoral blood. A twofold increase in cases with high concentrations of fentanyl (>100 ng/mL) was observed between 2021 and 2022. The minor metabolite and precursor chemical, 4-ANPP (4-anilino-N-phenethylpiperidine) may help differentiate between illicit and licit fentanyl. 4-ANPP blood concentrations were <10 ng/mL in 98% of the cases and the 4-ANPP:fentanyl ratio was <0.67 for 99.1% of blood specimens. Only six cases had 4-ANPP concentrations higher than the corresponding fentanyl blood concentration. This study also highlights, the changing fentanyl analogs found in postmortem cases since 2016 in NYC with the emergence of fluorofentanyl initially identified in 2020 and continuing to dominate in comparison with the prevalence of other analogs, many of which are no longer detected in casework. The detection of one of the latest drugs to be mixed with fentanyl, namely xylazine, has also increased in prevalence by 36.7% in 2022 compared with 2021. 相似文献
355.
Soren Blau PhD Eden Johnstone-Belford MSFS Samantha K. Rowbotham PhD 《Journal of forensic sciences》2023,68(4):1372-1378
In cases where human remains are unidentified because there is no initial identification hypothesis, limited contextual information, and/or poor preservation, radiocarbon (14C) dating may be a useful tool to further assist with identification. Through measuring the amount of 14C remaining in organic material, such as bone, teeth, nail, or hair, radiocarbon dating may provide an estimated year of birth and year of death for a deceased person. This information, may assist in, establishing whether a case of unidentified human remains (UHR) is actually of medicolegal significance and therefore, requires forensic investigation and identification. This case series highlights the application of 14C dating to seven of the 132 UHR cases in Victoria, Australia. Cortical bone was sampled from each case and the level of 14C was measured to provide an estimated year of death. Four of the seven cases analyzed contained the levels of 14C consistent with an archeological timeframe, one contained a level of 14C consistent with a modern (i.e., of medicolegal significance) timeframe, and the results for the remaining two samples were inconclusive. Applying this technique not only reduced the number of UHR cases in Victoria but also has investigative, cultural, and practical implications for medicolegal casework in general. 相似文献
356.
357.
地区间主义研究:成就与缺失 总被引:1,自引:0,他引:1
地区间主义是国际关系的新实践,同时也正在成为国际关系研究的新领域。国外学术界围绕地区间主义的内涵与外延、动力与功能以及其与地区主义和多边主义的关系进行了初步的研究。尽管国内学者在该领域的研究仍在相当程度上延续着西方的议程,然而也有部分学者试图在研究对象、研究方法和研究取向上做出超越。就该议题的未来发展而言,比较分析和理论化应当是两大基本趋势。而对中国学者来说,面临的最大挑战在于把握地区间主义研究的共性与个性,并善于从已有的研究议程中提炼出符合中国国家利益和国际战略需求的新的议程。 相似文献
358.
Beatriz Cuadrado Ballesteros Isabel M. García Sánchez José M. Prado Lorenzo 《International Public Management Journal》2013,16(1):53-84
ABSTRACT The process of local decentralisation of public services delivery has attracted research attention because of the wide range of factors that induce governments to make this decision. Nonetheless, most such studies have focused on economic and financial aspects, ignoring the impact of political factors. The scarce previous research about political factors is the motivation for this study. We used panel data models based on 153 Spanish municipalities with populations over 50,000 for the period 1999–2007. The process of decentralisation is disaggregated according to the legal form of the entities: corporations and foundations. Our results show that more corporatisation processes are carried out in environments where political competition is lower and the party in power enjoyed greater support in the last elections. Additionally, decentralisation processes usually take place in the years immediately following elections, especially through foundations. Furthermore, both forms of decentralisation are more likely to be initiated by right-wing politicians. 相似文献
359.
Evangelos Dragonas MSc Costas Lambrinoudakis PhD Michael Kotsis MSc 《Journal of forensic sciences》2024,69(1):117-130
CCTV surveillance systems are ubiquitous IoT appliances. Their forensic examination has proven critical for investigating crimes. DAHUA Technology is a well-known manufacturer of such products. Despite its global market share, research regarding digital forensics of DAHUA Technology CCTV systems is scarce and currently limited to extracting their video footage, overlooking the potential presence of valuable artifacts within their log records. These pieces of evidence remain unexploited by major commercial forensic software, yet they can hide vital information for an investigation. For instance, these log records document user actions, such as formatting the CCTV system's hard drive or disabling camera recording. This information can assist in attributing nefarious actions to specific users and hence can be invaluable for understanding the sequence of events related to incidents. Therefore, in this paper, several DAHUA Technology CCTV systems are thoroughly analyzed for these unexplored pieces of evidence, and their forensic value is presented. 相似文献
360.
Bradley J. Adams PhD Erin Butler MS Stephanie M. Fuehr MA Fransheska Olivares-Pérez MS Alexandra Semma Tamayo MSc 《Journal of forensic sciences》2024,69(2):391-399
Age estimation is an important component of decedent identification. When assessing adult remains, anthropologists frequently use gross examination of skeletal elements, such as clavicles, ribs, and pubic symphyses. For fleshed bodies, this requires the removal of these elements and maceration prior to analysis. A new method was developed using radiographic imaging to estimate age from degenerative changes of the lower thoracic and upper lumbar vertebrae. This technique will complement anthropological age estimation methods in young and middle-aged adults and may serve as a stand-alone method for older individuals. Digital radiographs from 240 medical examiner cases were evaluated. The sample included 120 females and 120 males between the ages of 18 and 101 years. A 3-phased scoring system was used for the target vertebrae. Transition analysis was conducted on binned average scores and a Bayesian approach was used to assign age intervals. At the 90% credible interval, individuals in Bin 1 were under 36 years of age while those in Bin 3 were over 47 years of age. Individuals in Bin 2 showed too much age variation to be informative. No significant differences were found between males and females. These findings will be especially useful in the age estimation of older adults and may eliminate the need for skeletal sampling in medicolegal cases where advanced degenerative changes are radiographically observed in the lower thoracic and/or upper lumbar vertebrae. This method was developed for use on fleshed individuals but may also be applicable to skeletonized remains. 相似文献