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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The storage of forensic evidence at the forensic science laboratory (FSL) in Pretoria

Van der Walt, Juanita 03 October 2011 (has links)
M.Tech. / It is the responsibility of the Forensic Science Laboratory (FSL) in Pretoria to analyse and store (DNA) evidence. This includes evidence received from the South African Police Service (SAPS), evidence in process and DNA stored for future analysis. Evidence is eventually presented and questioned in court and the flow of the evidence from the crime scene to the courts must be validated by ensuring that contamination does not take place at any point during the evidence supply chain, including the collecting, handling and documenting thereof. Rectifying mistakes in this process could be costly to the judicial system, not only in monetary terms, but in time and resources. The main purpose of this study has therefore been to investigate the FSL as a storage facility and to identify the warehousing activities that take place. In order to fulfil this purpose, the study covers the following aspects: the role and importance of the evidence supply chain the storage of evidence at the FSL the warehousing activities and procedures of the FSL, for example: the tracking and order picking of evidence the storage facilities and systems of the FSL, for example: the Electronic Management System (EMS) the customer service provided by the FSL conclusions and recommendations regarding the flow of DNA evidence from receipt of evidence up to delivering the findings after analysis of evidence at the FSL. The study includes detailed case studies of DNA evidence and its uses, as well as information of the storage and warehousing of DNA evidence at the FSL.
22

The application of DNA profiling to the identification of victims in the Gulf War (1990-1991)

Alenizi, Mohammad Abdullah January 2009 (has links)
This project was designed and developed in response to the need to improve the methodology employed in the DNA profiling of the Kuwaiti victims of the First Gulf War (1990-1991). The main challenges have involved developing the methodology in an attempt to increase the DNA recovery from the skeletal remains and also assess the preservation of DNA in the remains. In addition, work was undertaken to assess two commercial STR amplification kits, the Identifiler® and MiniFilerTM, to establish allele frequency databases for use in Kuwait and to assess the concordance of the two kits. In order to assess the methodology for DNA extraction and prediction of DNA preservation two sources of materials were used: simulated casework samples and actual casework samples. To obtain simulated casework samples, bones from sheep and teeth from human were buried at three different sites within Kuwait. These were sampled over a period of 60 weeks. In addition, samples from the femur and humerus of 25 individuals who were killed during the Gulf War, but had not yet been identified, were taken for analysis. These were exhumed from five gravesites, three in Iraq and two in Kuwait. Previous attempts to generate DNA profiles from the samples had failed. Different extractions protocols and purification methods were assessed including: a phenol:chloroform-based extraction; the GENECLEAN® Kit (Obiogene); QlAquick Gel Extraction kit (Qiagen); the QIAamp DNA Blood Maxi kit (Qiagen), using a protocol based on Davoren et al (2007); and a modified silica-based extraction using the DNeasy® Blood and Tissue Kit (Qiagen). PCR amplification of the extracts and the real-time quantification results showed that the modification of a silica-based method, using the Qiagen DNeasy® kit, was successful in removing inhibitors that were present in the extracts and obtained with all the other extraction methods. This allowed the successful profiling of 19 out of the 25 samples that had previously failed. In an attempt to further improve the DNA extraction efficiency, the effect of Nphenacylthiazolium bromide (PTB) was assessed. PTB has been reported previously to improve DNA extraction from ancient DNA samples (Paabo, 1989; Poinar et al., 1998) by releasing DNA that has become cross-linked with proteins. In this study, the effect of PTB, while statistically significant when used with samples from some sites, was minimal. The power of different methods to allow an effective system of triage (sorting of samples based on the likelihood of successful analysis) was examined. Three parameters were assessed: gross morphology, histology, and chemical status of the bones were compared with the amount and quality of DNA that was recovered from different samples. The simulated casework samples displayed only minor changes in gross morphology and histology over the period of the study, whereas the casework samples displayed varying degrees of change. The samples from Iraqi sites generally displayed good morphological and histological preservation. In contrast, the samples from the two sites within Kuwait displayed an almost complete lack of histological features and changes (pitting/cracks) to the surface. The morphological and histological preservation correlated closely with the success rate when extracting DNA from casework samples that were buried in Iraq and Kuwait. Nitrogen content in all samples was very similar and the results showed that it was not a useful indicator of preservation. The MiniFilertM (Applied Biosystems) is designed for the analysis of degraded DNA. Before applying this to casework, it is important to carry out a concordance study in order to ensure the results with the MiniFilerTM are comparable to the Identifiler® (Applied Biosystems) DNA profiles. The reference database with relatives' DNA profiles are all generated using Identifiler®. To assess the concordance, the MiniFilerTM profiles from 200 unrelated Kuwaiti samples were compared to Identifiler® profiles. Concordance was observed for 99.875% of the compared loci (1598 of 1600). The two discordant profiles displayed allelic dropout: one at the Dl 35317 locus due to non-amplification of allele 10 in the MiniFilerTM profile, and one at the D18S51 locus due to nonamplification of allele 18 in the Identifiler® profile. Finally, since the population of Kuwait is heterogeneous, with a strong tribal system, the possibility of subpopulation effect within the Kuwaiti population was examined. Allele frequencies for the 15 STR loci included in Identifiler® kit were ascertained in a sample population of 502 unrelated Kuwaiti individuals. The results were compared with 6 different populations. The Kuwaiti population was very similar to neighboring Iraqi and Saudi populations. These data are now used in casework undertaken in Kuwait, to calculate the statistical significance of matching DNA profiles (the results of the reference database work are included in Appendix 1 rather than in the main body of the thesis).
23

The development of PCR internal controls (PICs) for forensic DNA analysis

Zahra, Nathalie January 2009 (has links)
Proper interpretation of DNA profiles depends on the quality of the DNA samples, the amplification efficiency and the success of post-PCR processing. Chemicals associated with forensic samples can affect the amplification process while random errors occurring during pipetting and electrokinetic injection can cause variability. This can lead to either a reduced signal or lack of DNA profiles. As recommended by the SWGDAM, laboratories carrying out DNA profiling have to adopt standardise and validate procedures, which lead to high levels of quality assurance and control. During amplification, monitoring is restricted to the use of exogenous controls, which are unable to identify issues associated with individual samples. To address this limitation, four PCR Internal Controls (PJC5) i.e. two Internal Amplification Controls (IACs) and two Internal Non-Amplifiable Control (INAC5), to be used with the AmpFtSTR® SGM Plus® kit were developed. The IACs (90 bp and 410 bp) and INACs (80 bp and 380 bp) fragments were generated from the plasmid pBR322 and added along with human DNA in a 12.5 gl PCR volume. During the reaction the IAC% and 1AC 41 0 are amplified non-competitively with ROX labelled primers, while the pre-labelled INAC80 and 1NAC 380 were not involved with the amplification process. Both sets of fragments were detected as red peaks on the electropherogram flanking the human DNA profile. To study the behaviour of the markers within the system and their effect on the performance and sensitivity of the assay, the PICs were used during the amplification of human DNA of different quantity and quality and with the addition of three common inhibitors. Initial experiments involving the individual development of the fragments showed that both the INACs and IACs can be successfully applied to the amplification of human DNA with SGM Plus® reaction under optimised conditions, without significantly impacting the quality of human DNA profile. As the INACs fragments are designed not to amplify during the reaction, they gave a stable signal that can be used to monitor the post-PCR sample processing. The peak height ratios (PHRs) of human DNA with that of the LNAC8 0 or 1NAC380 can also be used to normalise the signal and assess the amplification efficiency of human DNA samples within replicates of the same sample run under the same conditions. The JACs on the other hand gave more information on the process of the PCR. They were able to monitor changes in the amplification efficiency and detect presence of inhibitors with a minimum inhibitory concentration closer to the SGM Plus® as compared to the Quantifiler® WC system. The IAC90 and 1AC410 ratios were also used to distinguish between partial profiles obtained from degraded DNA and those resulting from partial inhibition. Combining the two sets of fragments together with the amplification of human DNA needed further reaction optimisation, involving the addition of dNTPs and MgCl2. The presence of PICs provided information on the amplification performance and post-PCR processing and can assist with the interpretation of human DNA profiles. The position of the fragments also allowed PICs to be used as sizing standard. Compared to the GSTh 500 ROXTM size standard, PICs showed a slightly lower sizing precision, with standard deviations lower than 0.3 bp. Even though this resulted in allelic bins higher than 1 bp limit for 99.7% confidence, all samples sized with PICs were correctly genotyped. The addition of PICs would be a valuable tool, in particular, for the analysis of compromised DNA. In particular it would be useful when analysing DNA recovered from skeletal remains, which are prone to accumulation of PCR inhibitors and DNA degradation.
24

Evaluation of insertion/deletion polymorphisms (INDELs) applied to forensic casework in Malaysia

Hassan, Nur Haliza Binti January 2017 (has links)
In Malaysia, as well as other forensic laboratories in tropical climates many of the crime scene samples received at the forensic laboratory are less than ideal. They are often present low amounts and/or degraded due to environmental exposure to high temperatures, sun and humidity for days or even months. STR analysis is widely accepted by forensic community, but sometimes this technique gives unreliable results when profiling degraded samples as the amplicons size are relatively larger (100 bp to 450 bp). While, miniSTR is a reduced size of STR amplicons which enables higher recovery of information from degraded samples, but only a few loci are amplified and allele drop out still may occur, as the amplicons are up to 200 bp. The percentage of recovery DNA profile from degraded DNA using mtDNA is much higher due to its present in cells at a much higher copy number than the nuclear DNA. However, the major drawback for mtDNA is labour intensive and has a low information value (i.e. it is not highly discriminating). Insertion/deletion polymorphisms (INDELs) are relatively new class of a DNA marker used in forensic casework; used most commonly as a supplementary method to STR (Short Tandem Repeat) based typing. INDELs, like SNPs (Single Nucleotide Polymorphisms), are particularly useful for the analysis of highly degraded DNA as the amplicon sizes are typically below 160 bp; they can also be valuable as an additional tool to help resolve kinship cases, with the advantage over STRs that do not have high mutation rates. INDELs have an advantage over SNPs in that they are length polymorphisms and so can be analysed by simply measuring the length of the allele(s). The Qiagen Investigator DIPplex® kit is currently one of two commercially available kits for the amplification of INDEL polymorphisms; it amplifies 30 biallellic INDEL loci and the amelogenin locus. The primers used are fluorescence labelled with 6-FAM, BTG, BTY and BTR. This technique is robust, relatively simple, and the results are analysed using the same capillary electrophoresis equipment and software as used for STR typing. The INDEL markers have simple biallelic structure and combine the advantages of STR and SNP assays. This study has established that the INDEL technique, using the Investigator® DIPplex PCR kit, is a simple, informative and sensitive approach for the typing of degraded DNA, as compared to STRs and SNPs. In this research, allele frequencies for 30 autosomal INDEL loci were studied in 500 unrelated individuals (100 each) from Malay, Malay-Chinese (M-Chinese), Malay-Indian (M-Indians), Iban and Bidayuh. The PCR amplification used the Qiagen Investigator® DIPplex kit. These population groups represent the majority of the population in Malaysia. No significant departure from Hardy Weinberg Equilibrium (HWE) expectations were observed for most of the INDEL loci analyzed (p-value >0.05) on the Malaysian population samples. The exceptions were HLD101 for Malay (p = 0.0009), HLD133 for M-Indian (p=0.005), HLD125 for Iban (p=0.028) and HLD93 for Bidayuh (p = 0.014). However, when the Bonferroni correction for multiple testing performed on the population samples, none of the previous p-values was significant. There were no Malaysian population studies was carried out using the Qiagen Investigator® Investigator DIPplex kit at the time of the research. This INDEL assay have undergo an extensive valdidation process and novelty report of the allele frequencies of INDELs would serve as reference database for individual identification in the Malaysian population in the future. Even the match probability of the STR is higher, INDEL still gives an acceptable value for forensic identification; e.g. linking different pieces of evidence or re-association of body parts in the case of human identification. Biological samples received in Malaysia forensic laboratory have often been exposed to unfavourable environmental conditions. This can lead to DNA degradation and end up in incomplete DNA profiles. It is difficult to distinguish between low template DNA that are producing no or partial profiles because of DNA degradation and those that produce no or incomplete profile because of PCR inhibition. Even though real-time PCR methods are available for quantification and detection of PCR inhibitors, the information received is limited as real-time PCR targets amplicons that are much smaller than those typically targeted in forensic analysis. To gain more information on the quality of extracted DNA, a new multiplex PCR assay comprising a Mini 4-plex targeting amplicons of 50 base pairs (bp), 70 bp, 112 bp and 154 bp along with two Internal Amplification Controls (IACs) of 90 bp and 170 bp was developed. The primers were redesigned from a 4 plex & IACs system developed by previous PhD UCLan students. This multiplex was optimised so that it worked efficiently on DNA template as low as 0.009 ng, which highlighted the strength of the Mini 4-plex system. The IACs were effective in detecting PCR inhibitors. The Mini 4-plex system (Mini 4-plex & IACs) was demonstrated to be an effective tool for identifying degraded and inhibited samples, which could be used to triage forensic samples in a casework laboratory. Therefore, this study has led to the improvement of new and novel markers assessing DNA degradation and PCR inhibition on forensic samples. This will demonstrate the compatibility with forensic laboratory workflows. The need of this Mini 4-plex assay in forensic laboratory can reduce time and cost of DNA analysis. Besides it will contribute to a good management samples, where after being assessed the samples can be decided to analyse using appropriate kit (e.g. miniFiler or INDEL). Indirectly, this will increase the quality of the sample itself. In order to increase the power of a 15 Mini-INDEL multiplex, which was developed earlier by UCLan PhD student, a total of 9 autosomal INDEL markers that are not part of the Qiagen Investigator DIPplex® kit were selected and redesigned from (Pereira et al. 2009). In this study a simple and sensitive INDEL multiplex was successfully developed for human identification. However, the discrimination power is still low when compared to STR systems, but has potential value when analysing highly degraded material. By combining the 15 Mini-INDELs and 9 Mini-INDELs allele frequency data, it will give beneficial by increasing the match probability values in future analysis.
25

An evaluation of genetic markers for forensic identification of human body fluids

Afolabi, Olatunde Abimbola January 2017 (has links)
Body fluids are commonly recovered from crime scenes by forensic investigators and their identification are necessary part of forensic casework study. Current body fluid identification techniques rely on enzymatic tests, which have limited sensitivity and specificity, they require large amount of template, use separate assays for various body fluids, and are prone to contamination. Various genes are expressed in different body fluids that could be used as genetic markers for body fluid identification, and are used in forensic investigations. The aim of this study was to use mRNA markers to identify human body fluids, which included blood, semen, saliva, vaginal secretion and menstrual blood. Initially, ten reference genes (UCE, TEF, GAPDH, 18S rRNA, ACTB, B2M, B-Actin, OAZ1, RPS 29 and S15) were studied to establish an appropriate reference gene in body fluid identification. These are constitutive genes used for normalisation of gene expression data and control of variations in experiments. qRT-PCR efficiency, sensitivity and limit of detection (LOD) were investigated using SYBR Green and Taqman probes. The results of the SYBR Green efficiency test experiment displayed five markers, UCE, TEF, ACTB, B2M, and RPS29 with 90-110% efficiency with a slope -3.33 ± 10%. Subsequently, Taqman probes were designed for the five markers and then used for the Taqman probe experiment. Reference gene stability test was carried out on body fluid samples stored up to 6 months at room temperature using the designed Taqman probe assays. The results established ACTB and UCE as best candidate reference gene markers in this study as both were most stable in samples stored for 6 months. Furthermore, to identify each of the five body fluids, thirty-two (32) body fluid specific mRNA markers were evaluated, optimised and validated. The experiment was initially carried out with non-fluorescent makers to determine the specificity of the markers. These were analysed using agarose gel electrophoresis. Further optimization was then carried out using fluorescently labelled markers. This was done in five separate multiplexes for each body fluid; –semen-plex, saliva-plex, vaginal secretion-plex, menstrual blood-plex and blood-plex. An attempt was made to combine all the five-separate multiplex into a single multiplex. All body fluids were identified unambiguously with no cross-reactions of non-target body fluids using the combined multiplex assays. Following further evaluation and validation tests, a total of 14 markers were selected and a capillary electrophoresis (CE) based, multiplex assay was developed to identify blood, saliva, semen and vaginal secretion samples simultaneously. The markers in the developed multiplex assay included ALAS2 and PF4 (blood), STATH and HTN3 (saliva), PRM1, TGM4, MSMB, NKX3-1 (semen), ACTB and UCE (reference genes), CRYP2B7P1, SFTA2, MUC4 and L. crispatus (vaginal secretion). Extensive validation, which include sensitivity, specificity, reduced volume reactions, degradation, reproducibility, mixtures, cycle number and mastermix, was carried out in accordance with the guidelines detailed in Scientific Working Group in DNA Analysis (SWGDAM). The 14-marker CE-based assay displayed high specificity and sensitivity. Each body fluid was detected down to 1:3000 dilution of mRNA except vaginal secretion that was detected down to 1:1500 dilutions of sensitivity. Specificity experiments showed no cross reactions of the assay with non-target body fluids. Reproducibility study displayed similar results reported from an independent laboratory. All body fluids exposed to environmental insult were identified up to at least day 30 of 51, with blood being identified up to day 51. In the mixture study, all body fluids were identified unambiguously using the developed multiplex assay. In conclusion, the results of this study have led to the development of a new and novel capillary electrophoresis-based mRNA marker assay for forensic body fluid identification, demonstrating its compatibility with forensic laboratory workflows. The use of this assay to profile forensic casework samples for body fluid identification would be a future application of this work.
26

Forensic clinics : a comparative study

Armstrong, John Maxwell January 1964 (has links)
The main purpose of this study is to examine the uses of forensic clinics in the administration of criminal justice as devices for the identification, diagnosis of treatment of psychiatric disorder in convicted offenders. A subsidiary aim of the study is to assess the feasibility of the establishment of such a facility in British Columbia. The thesis is introduced by an account of those changes in the criminal law which have resulted in its ceasing to be a simple instrument of deterrence and in increasing attention being paid to the principles of extenuation and rehabilitation. An attempt is then made to survey and evaluate recently published data on the prevalence and distribution of mental disorders in criminal populations, and the conclusion is drawn that approximately one fifth of all persons convicted of an indictable offence in typical North American jurisdictions are suffering from psychiatric problems serious enough to play an important part in their prospects of rehabilitation, even if those problems have had little direct causal significance in the commission of the original crimes. This is followed by a survey of the statutory auspices, administrative structures, clinical programs and financial bases of eight established forensic clinics, seven in the United States and one in Canada. This survey, together with material drawn from the published literature of criminology and public administration, serves as the basis of an attempt to formulate the requirements of an "ideal" forensic clinic. The model synthesized in this fashion is then applied to the local Provincial situation and a series of recommendations are made concerning the procedures to be followed and the principles to be observed in establishing a forensic clinic in British Columbia. The principal desiderata of effectiveness for a forensic clinic identified in the thesis are that: (1) in regard to both staffing arrangements and the character of its program, the clinic should be inter-disclipinary rather than purely psychiatric; (2) it should be expected to give purpose and precision to existing correctional facilities in the penal system, and not to compensate for the fact that none actually exist; (3) it should have no fixed commitment to dealing exclusively with one particular class of offenders (such as sexual offenders), but should hold itself ready to deal with any offenders whose problems and whose treatment it can competently advise on; (4) its workloads should never be such as to reduce its activities to routine levels or raise the dangers of perfunctoriness; (5) it must be sensitive to the working problems and needs of the courts of criminal justice but independent of direct control by the judiciary. / Arts, Faculty of / Social Work, School of / Graduate
27

Violence against women : epidemiology and pathology of femicides and suspected sexual homicides in Cape Town : a 10-year follow-up study

Molefe, Itumeleng January 2016 (has links)
Background: Violence against women (VAW) is the most pervasive human rights abuse and a global health threat. The most extreme forms of physical and sexual violence are the intentional killing of a woman (femicide) and rape, or the combination of both in the form of r ape homicide, preferably termed 'sexual homicide' in this study. Motivation: Martin's research in 1999 reported a rape homicide incidence rate of 12.3/1000 female rapes reported to the police in Cape Town while the National study performed by Abrahams et al in 1999 reported an incidence rate of 10.9/1000 female rapes reported to the police in South Africa (SA). These high incidence rates, definitional problems, methodological limitations, changes in the law, and inconsistent management of suspected sexual homicides motivated the author to undertake this follow - up study. Objectives: To describe the epidemiology and pathology of femicides in Cape Town and thereby identify risk factors, magnitude and criteria for suspected sexual homicides. Design and Methodology : This is a retrospective descriptive study. Data was collected from autopsy reports of female bodies admitted at Salt River Forensic Pathology Laboratory in Cape Town from the years 2000 to 2009. A 10 - year period improves the sample size and the validity of the results. Limitations : Time constraints led to inadequate information on perpetrators of femicides and therefore a report on intimate femicide is limited in this study. Main findings and Discussion: Results showed an average femicide incidence rate of 12.4/100,000 female population in Cape Town Western Metropole which is half the South African national incidence for 1999, equates to the 2009 national rate and is almost five times the global average. Sexual homicide was suspected in 19.9% of all femicides, slightly higher than the 16.3% previously reported by Martin for Cape Town. The median age of victims was 32 years. Most femicide victims died from gunshot injuries (35.2%) followed by those who were stabbed (29.6%), while the majority (35.7 %) of victims of suspected sexual homicide died from asphyxial deaths, including strangulation. Taking specimens for the Sexual Assault Evidence Collection Kit correlated significantly with genital (77.7%) and anal injuries (64.5%), and 41% of femicide victims had alcohol levels above 0.05g%. Conclusion: The incidence of femicide and sexual homicide in Cape Town is higher than previously reported. Gun violence and alcohol abuse are persistent problems. Recommendations : Findings should be used to motivate for intersectoral collaboration in the form of female homicidal death review (FHDR) teams. These teams should aim to develop standardised guidelines for the forensic management, prosecution, prevention and monitoring strategies for femicides and sexual homicides in South Africa.
28

Retrospective analysis of deaths in the Table Mountain National Park 2000-2011

Maistry, Sairita January 2015 (has links)
Includes bibliographical references / Background: The TMNP is one of the more famous of Cape Town's tourist attractions. Stretching across the Peninsula, this conservation site is home to rare indigenous flora and fauna, biodiverse habitats and the spectacular Table Mountain. Despite its seemingly safe infrastructure, there have been media reports of accidents and deaths that have occurred in the TMNP and on Table Mountain. Aim: To determine the number and types of fatalities in the TMNP from 2000-2011. Method: The Salt River Forensic Pathology Laboratory is a state mortuary which serves the Cape Peninsula. Included in its drainage area is the TMNP. Approximately 3000 medico legal investigations are performed per annum, the details of which are stored in databases at the SRFPL and at the Division of Forensic Medicine at the University of Cape Town. These and archival records were retrospectively searched for all deaths that occurred in the National Park between 2000 and 2011. The collected information was categorised and analysed according to the demographic profile of victims, cause and manner of death, blood alcohol levels and activities prior to death. Results: Between 2000 and 2011, there were 98 confirmed deaths in the TMNP. The deaths occurred mostly during the South African summer months and on Fridays and Sundays (weekends). The victims were predominantly Caucasian (59%) and male (90 %) with a mean age of 39.4 years. The majority of victims were local, while 15 % were foreign, European and tourists. Overall accidents contributed to 53% of all unnatural deaths with victims predominantly sustaining head injuries and polytrauma which occurred from falls (71%) during mountain recreational activities. 24% of victims who fell tested positive for alcohol (>0.01g/100ml). Body mass index (BMI) calculations of the 98 victims revealed that 53% had BMI above 25. A p re -existing medical condition (predominantly cardiac) was the cause of the natural deaths. 26 A significant finding of the study was that 22% of deaths were due to suicides that took place on or surrounding Table Mountain. Suicides occurred commonly during summer with Fridays and Mondays being the common suicide days. The victims, all men, in the age range of 30-39 years (mean age of 39 years) were predominantly Caucasian (68%) and used hanging (45%) and jumping (27%) off the mountain as the two most preferred methods of death. 22% of suicide victims tested positive for alcohol at time of death. Conclusion: The TMNP is one of South Africa's most popular tourist attractions, due largely in part to the presence of Table Mountain. A retrospective study of deaths that occurred within the Park and on the mountain range over a 12-year period identified a predominantly Caucasian male victim demographic and found that head and polytrauma sustained from falls while participating in mountain associated activities as the leading cause of death. A significant finding was the high percentage (22%) of suicide deaths that took place. This study has helped to identify Table Mountain as a possible local suicide hotspot and points to a need for TMNP authorities to include in their safety protocols, strategies for suicide prevention. Larger collaborative studies are recommended as this would significantly impact on public health through the improvement of Park and mountain safety.
29

Retrospective review of paediatrics patients involved in pedestrian vehicle accidents in greater cape Town

Moller, Izelle 16 February 2021 (has links)
Pedestrian vehicle injuries are a growing public health threat worldwide. In South Africa, pedestrian accidents are the leading cause of injury related deaths in children younger than 15 years. There is international and national research looking at various aspects of pedestrian vehicle accidents. Previous studies have highlighted the general distribution of injuries sustained in paediatric pedestrian accidents. However, the specific types of injuries sustained by children pedestrians in different age groups have not been widely researched. We conducted a retrospective review of children involved in road traffic accidents as pedestrians in the greater Cape Town area from 2011 to 2015. The study population included patients below the age of 13 years that were admitted to Red Cross Children's Hospital (RCCH), as well as those subjects that died and presented to the Forensic Pathology Laboratory in Salt River also known as Salt River Mortuary (SRM). The age group 0-12 years was selected because RCCH is a referral paediatric hospital that only admits children under the age of 13 years. Data obtained from the study population were analysed according to age, gender, time, date (day of week and month) and area of accident, as well as injuries sustained. Cases were grouped according to age in order to analyse and compare changes in injury patterns for different groups. Age groups 0-4 years, 5-9 years and 10-12 years were selected. Further comparison of the injuries sustained was made between children admitted to RCCH (survivors) and subjects admitted to SRM (deceased). During the 5-year period 552 children were admitted to RCCH and 109 cases were admitted to SRM with 2:1 male to female predominance in both study groups. In our study, the group with the highest number/percentage of deaths was children aged 0 – 4 years, which contrasts with previous research. Most of the accidents (75-80%) occurred in lower socioeconomic areas. Significantly more head injuries occurred in children who died from their injuries than those who survived (96% versus 18%) (p < 0.0001). Out of the children who demised, 27% had spinal injuries, 61% had chest injuries and 43% had abdominal injuries, all of which were significantly higher than children who survived (p < 0.0001 for each). Upper limb injuries were equal between the two groups (12% vs 13%) and lower limb injuries were more common in the survivors (46% vs 24%). These results are the first to be documented in Cape Town and provide insight into the nature of injuries sustained by children involved in pedestrian vehicle accidents.
30

Evaluation of scale placement and camera angle in footwear impression examination

Rodriguez, Marisol 11 October 2019 (has links)
Footwear impressions can be found at any type of crime scene. Footwear impressions are valuable pieces of physical evidence when discovered, properly documented and collected. Two-dimensional footwear impressions can be left behind when the outsole of a shoe comes into contact with a substance and then the substance is transferred to a surface, leaving a positive impression on that surface [1-3]. 2-D impressions can also occur when a shoe steps onto a dusty surface and the dust adheres to the tread elements, which take away the dust leaving behind a negative impression [2,3]. Footwear impression evidence may display class characteristics, such as the type, manufacturer, the approximate size and shape and general description of the shoes [2]. They are most commonly documented and collected through photography, specifically examination quality photographs. The value of the photographs taken depends on the quality of the images and requires the correct placement of the scale and angle of the camera. In order to ensure an accurate representation of the evidence, the camera should be parallel to the impression and a scale must be present in the same plane as the impression. Taking photographs at any other angle can distort the object in the photograph, resulting in incorrect measurements, which can hinder the comparison process between the photographed object and the physical object. Digital imaging applications and software can be used to calibrate images, meaning the scale is used to adjust, or calibrate, the photographed image into a 1:1 image or actual size. Forensic photography guidelines provided by SWGTREAD stress the importance of scale placement and the position of the camera lens, but research on how exact these two steps must be executed to accurately determine the physical size or dimensions of the shoe remains limited [3,4]. The goal of this project was to determine how the positioning of a scale in relationship to the footwear impression can potentially lead to possible distortion of the actual size of the photographed impression. This project seeks to evaluate the extent to which the depth of the scale and impression can vary before the size of the photographed impression becomes measurably distorted as well as evaluate the tolerable range of angle tilt of the scale allowed before the size of the photographed impression becomes distorted. A left counterfeit Nike Air Jordan’s shoe from the Jordan Melo line, US adult size 7.5 was used to make several test impressions and then the best impression with the highest quality was chosen to be photographed. Examination quality photographs of the test impression with the scale in the same plane were taken, followed by an incremental increase in the height/distance (0-66.9 mm) of the scale from the ground and lastly, with an incremental increase in the angle (0-20 degrees) of the camera horizontally, vertically left and right. The photographs were then calibrated using Adobe® Photoshop® and actual size images were printed out. Based on the tread design, ten areas present on the outsole were examined through measurement. The results indicated that if the scale was placed at a height within 5.7 mm of the height of the impression, then there would be no change in estimated shoe size. However, if the scale was placed a distance or height of 7.6 mm or greater from the bottom of the impression, then the image would result in a change of half a shoe size or more. Also, if the angle of the camera was greater than 8 degrees horizontally or greater than 14 degrees vertically to the left there was a change in the apparent shoe size. However, there was no change in the shoe size when the camera angle increased horizontally up to 8 degrees, vertically up to 20 degrees, and vertically up to 14 degrees. It is important to be aware of discrepancies that can exist in size dimensions when the scale placement and camera angle are not in the correct plane and position. The distorted images may result in false measurements, which can lead to inaccurate size interpretations. This would be problematic when comparing a suspect’s shoe to the photographed footwear impression, possibly resulting in false inclusion or exclusion decisions of the questioned footwear impression.

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