Matching Items (9)
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- All Subjects: Forensics
- Creators: School of Mathematical and Natural Sciences
- Member of: Theses and Dissertations
- Resource Type: Text
Description
Bloodstain pattern analysis can provide telling evidence from a crime scene based on the clues left in the blood, but the field itself is highly problematic since the evidence extracted is dependent upon the interpretation of the analyst. Although some aspects of this type of analysis have been scientifically supported, most are not seen as positively accurate. Since certainty is the basis for acceptance of courtroom testimony, it is important that these unsettled aspects become more understood. This experiment examines the diameter of a weapon and how it affects its cast-off pattern. Weapons with four different diameters were used to generate 5 sample patterns under controlled conditions from each weapon diameter for a total of 20 patterns consisting of 3,367 droplets. The length and width of the pattern, the total number of droplets in the pattern, and the percentage of each droplet type (classified into low-velocity, medium-velocity, and high-velocity droplets) were recorded, averaged, and compared to each other individually using a t-test difference of two means assuming unequal variances. The results reveal that a higher percentage of droplets greater than 4 mm may indicate the use of a weapon with a wider diameter. The data also shows differences between the weapons that may be related to other factors besides the diameter of the weapon such as surface area or the curvature of the weapon. Still, more testing must be conducted to support these theories.
ContributorsBetz, Alexandra Marie (Author) / Kobojek, Kimberly (Thesis director) / Jacobson, David (Committee member) / School of Humanities, Arts, and Cultural Studies (Contributor) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Is it possible to treat the mouth as a natural environment, and determine new methods to keep the microbiome in check? The need for biodiversity in health may suggest that every species carries out a specific function that is required to maintain equilibrium and homeostasis within the oral cavity. Furthermore, the relationship between the microbiome and its host is mutually beneficial because the host is providing microbes with an environment in which they can flourish and, in turn, keep their host healthy. Reviewing examples of larger scale environmental shifts could provide a window by which scientists can make hypotheses. Certain medications and healthcare treatments have been proven to cause xerostomia. This disorder is characterized by a dry mouth, and known to be associated with a change in the composition, and reduction, of saliva. Two case studies performed by Bardow et al, and Leal et al, tested and studied the relationships of certain medications and confirmed their side effects on the salivary glands [2,3]. Their results confirmed a relationship between specific medicines, and the correlating complaints of xerostomia. In addition, Vissink et al conducted case studies that helped to further identify how radiotherapy causes hyposalivation of the salivary glands [4]. Specifically patients that have been diagnosed with oral cancer, and are treated by radiotherapy, have been diagnosed with xerostomia. As stated prior, studies have shown that patients having an ecologically balanced and diverse microbiome tend to have healthier mouths. The oral cavity is like any biome, consisting of commensalism within itself and mutualism with its host. Due to the decreased salivary output, caused by xerostomia, increased parasitic bacteria build up within the oral cavity thus causing dental disease. Every human body contains a personalized microbiome that is essential to maintaining health but capable of eliciting disease. The Human Oral Microbiomics Database (HOMD) is a set of reference 16S rRNA gene sequences. These are then used to define individual human oral taxa. By conducting metagenomic experiments at the molecular and cellular level, scientists can identify and label micro species that inhabit the mouth during parasitic outbreaks or a shifting of the microbiome. Because the HOMD is incomplete, so is our ability to cure, or prevent, oral disease. The purpose of the thesis is to research what is known about xerostomia and its effects on the complex microbiome of the oral cavity. It is important that researchers determine whether this particular perspective is worth considering. In addition, the goal is to create novel experiments for treatment and prevention of dental diseases.
ContributorsHalcomb, Michael Jordan (Author) / Chen, Qiang (Thesis director) / Steele, Kelly (Committee member) / Barrett, The Honors College (Contributor) / College of Letters and Sciences (Contributor)
Created2015-05
Description
Abstract Latent fingerprints are a critical component of the evidence that is captured and analyzed from crime scenes and presented for convictions in court. Although fingerprint science has been used for many years in forensics, it is not without many criticisms and critiques from those that believe it is too subjective. Researchers from many disciplines have tried to refute this claim by completing experiments that would eventually lead to a fingerprint aging technique as well as providing statistical models and mathematical support. In this literature review, the research that has been widely published and talked about in this field was reviewed and analyzed to determine what aspects of the experiments are benefitting the study of degradation. By carefully combing through the methods and results of each study, it can be determined where future focuses should be and what disciplines need to be exploited for knowledge. Lastly, an important aspect of the experiments in recent years have depended on the collaboration with statistics so this evidence was examined to identify what models are realistic in determining error rates and likelihood ratios to support latent fingerprint evidence in court. After a thorough review, it is seen that although large strides have been taken to study the degradation of fingerprints, the day where fingerprints will be able to be definitively aged may be ways away. The current experiments have provided methods such as three-dimensional and visual parameters that could potentially find the solution, but also uncovered methods such as immunolabeling and chemical composition that face major challenges. From the statistically point of view, researchers are very close in developing equations that exploit the likelihood ratios of similarity and even calculate the various possible error rates. The evidence found in this review shows that science is one step closer to the age determination of fingerprints.
ContributorsPorter, Lindsey Jordan (Author) / De Alcaraz Fossoul, Josep (Thesis director) / Mancenido, Michelle (Committee member) / School of Criminology and Criminal Justice (Contributor) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
As human beings we go through the world interpreting – seeing a situation, gathering context, and making a decision on the meaning of the thing we just experienced. The philosopher Martin Heidegger calls this way of being hermeneutics – a practice of interpretation. This method of approach does not ignore a person’s bias, instead bias is highlighted, understood, and possibly even overcome. In the following pages the basic definition and process of hermeneutics will be discussed. Leading into the difference between calculative and meditative thought – scientific and philosophical – in order to later discuss the possibility and need to merge the two in the field of Forensic Science. Forensic Scientist uses hermeneutic thought by way of merging calculative and meditative thinking. In order to support this claim artistic renderings of ‘the pieces of an unknowable whole’ were created to literally illustrate this truth.
Forensic science is tasked with using calculative thinking with scientifically accepted methods of measurement and detection as well as the meditative task of applying their data to messy, real-world events. In order to support my supposition of forensic scientists being hermeneutical workers, three paintings were created. The three paintings can be considered a tryptic of sorts due to the context in which they are presented: forensic science. They each tell a story that is weaved within each other – spatter indicating violence long past, the empty void of a body gone, and the cold decomposition of a victim found. It is the forensic scientist that must interpret each piece separately and is tasked with finding how and why they are put together. The hermeneutical work of the forensic scientist interpreting a crime scene uses the same methods as one who interprets text. A forensic scientist opens possibilities of meaning in the same way that Martin Heidegger’s hermeneutic circle does. There is interplay between the interpreter (the forensic scientist) and the text (the crime scene), questions are formed (what happened here?) and responses are made (evidence found at the scene). This question and response outlook is what make the forensic scientist a hermeneutic thinker.
Forensic science is tasked with using calculative thinking with scientifically accepted methods of measurement and detection as well as the meditative task of applying their data to messy, real-world events. In order to support my supposition of forensic scientists being hermeneutical workers, three paintings were created. The three paintings can be considered a tryptic of sorts due to the context in which they are presented: forensic science. They each tell a story that is weaved within each other – spatter indicating violence long past, the empty void of a body gone, and the cold decomposition of a victim found. It is the forensic scientist that must interpret each piece separately and is tasked with finding how and why they are put together. The hermeneutical work of the forensic scientist interpreting a crime scene uses the same methods as one who interprets text. A forensic scientist opens possibilities of meaning in the same way that Martin Heidegger’s hermeneutic circle does. There is interplay between the interpreter (the forensic scientist) and the text (the crime scene), questions are formed (what happened here?) and responses are made (evidence found at the scene). This question and response outlook is what make the forensic scientist a hermeneutic thinker.
ContributorsCraig, Catherine Anne (Author) / Kobojek, Kimberly (Thesis director) / Watrous, Lisa (Committee member) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The effects that forensic-themed programs such as CSI: Crime Scene Investigation has on the public's understanding and expectations of the criminal justice system has been a main focus of study in recent years. This phenomenon was coined by the media and termed the "CSI Effect." This study aimed to research the correlations between age, gender, and program-watching habits on potential juries' evidence expectations in court. To do so, 70 people were surveyed and asked a series of demographic questions, as well as questions about how often they watch forensic-themed shows and their experience with the criminal justice system. They were given a mock crime scene scenario and asked about their scientific and non-scientific evidence expectations in this particular case. The most notable results showed that a longer exposure time to forensic-themed programs correlated to high evidence expectations. However, how often viewers watch forensic-themed programs did not seem to affect their evidence expectations. It was concluded that the higher evidence expectations by modern jurors may be due to a combination of the "CSI Effect" and the newly hypothesized "Tech Effect," instead of just being the consequence of the watching too much forensic-themed television.
ContributorsJones, Kristin Taylor (Author) / Kobojek, Kimberly (Thesis director) / Lafond, Sue (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Natural Sciences (Contributor)
Created2014-05
Description
Due to the nature of animals, even domesticated pets, animal scavenging of human remains is an important taphonomic factor. This area of study has, however, been undercounted in the current literature. The purpose of this study was to begin the first step in creating a taphonomic profile for urban / household animal scavenging as distinguishable from manmade tool marks. Using volunteered animals and regularly available tools, alterations were made on beef ribs in order to characterize the distinguishing profiles between the two groups. It was found that animal scavenging alterations, in the short term (20 minutes used in this study) have a distinctly different appearance than tool mark alterations. Animal scavenging has less visible alterations, consistent bite morphology across different species, and symmetrical cut marks along the midsection of the long bones. Ultimately, this study was a successful first step in furthering taphonomic alteration database research across various biomes and conditions.
ContributorsLittle, Cody Lee (Author) / Kobojek, Kimberly (Thesis director) / Falsetti, Anthony (Committee member) / Ball, Becky (Committee member) / School of Human Evolution and Social Change (Contributor) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Ancestry estimation in forensic anthropology has been one of the most complex determinations to make from the human skeleton. There is a long history in biological anthropology using different morphological characteristics from the skull and other areas of the skeleton but it remains a difficult estimation that always has some variability. Currently, more studies have been conducted in morphological and metric methods from the skull of ancestry estimation to better the accuracy of the determination. Since most forensic cases are not in the best condition, there also must be other estimation methods from other bones from the remains such as the cervical vertebrae and the femur. These methods have some degree of accuracy but are not as commonly used in forensic cases as the skull is. It seems that the best method for ancestry estimation is to use a combination of multiple methods, having multiple lines of evidence. With the advent of DNA, many researchers have started to study the use of DNA in ancestry estimation. Genetics can be used in ancestry estimation as certain populations have allele frequencies that can be quantified. Using ancestry informative markers (AIMS), DNA can be used to estimate the ancestry of an individual as well as the amount of admixture in the individual. Many different methods have been tested in genetic evaluation of ancestry and have been supported with good accuracy. However, DNA analysis is expensive and time consuming, putting more reliance on osteological methods. Social implications have had a tremendous impact on the fate of ancestry estimation in forensic anthropology. Anthropology has generally rejected the notion of races but it is still used in forensics due to how much it is inculcated into everyday society. Also, the overarching theme of admixture is becoming more prevalent in society. This causes the estimations in forensic anthropology to be extremely difficult. If more research into ancestry estimation does not continue, the determination will almost be impossible to be made.
ContributorsDowell, Kori Kalei (Author) / Falsetti, Anthony (Thesis director) / Kanthaswamy, Sreetharan (Committee member) / School of Human Evolution and Social Change (Contributor) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
The subcategory of evidence deemed trace evidence is frequently seen in crime scenes, and while it is commonly the smallest evidence around, that doesn’t stop it from greatly contributing to the findings at the scene. Blood evidence may be categorized into this group in certain cases at crime scenes, especially in cases of transfer between two objects or people. In this study, the transfer of blood across both porous and non-porous substrates was examined to determine the persistence of blood across both substrates. The resulting stains after each trial of transfers were tested with a presumptive blood test commonly used in crime labs, the Kastle-Meyer test. Throughout all trials of the experiment, it was determined that blood on a non-porous surface typically dries faster as long as there isn’t a pooling effect, which hinders the ability for a stain to be continuously transferred and detected by Kastle-Meyer. Conversely, porous substrates are more likely to absorb and retain the blood in the material, allowing the blood to be released when pressure is applied, causing the stain to transfer more easily and result in a stain that will produce a positive Kastle-Meyer result.
ContributorsKincade, Morgan (Author) / Weidner, Lauren (Thesis director) / Kobojek, Kimberly (Committee member) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
The use of DNA testing has been focused primarily on biological samples such as blood or saliva found at crime scenes. These types of evidence in the forensic field are sometimes difficult to come by, especially when there is no body to find to verify things such as identity or status of a person. In the case of the burial of a body, they can be remote and relocated multiple times depending on each situation. Clandestine burials are not uncommon especially in the Arizona desert by the United States and Mexico border. Since there is no physical body to find the next best avenue to finding a clandestine burial is through search teams which can take weeks to months or other expensive technology such as ground penetrating radar (GPR). A new more interesting avenue to search for bodies is using the most found material–soil. Technology has allowed the possibility of using soil DNA microbiome testing initially to study the varieties of microbes that compose in soil. Microbiomes are unique and plentiful and essentially inescapable as humans are hosts of millions of them. The idea of a microbiome footprint at a crime scene seems out of reach considering the millions of species that can be found in various areas. Yet it is not impossible to get a list of varieties of species that could indicate there was a body in the soil as microbiomes seep through from decomposition. This study determines the viability of using soil microbial DNA as a method of locating clandestine graves by testing 6 different locations of a previous pig decomposition simulation. These two locations give two different scenarios that a body may be found either exposed to the sun in an open field or hidden under foliage such as a tree in the Sonoran Desert. The experiment will also determine more factors that could contribute to a correlation of microbiome specific groups associated with decomposition in soil such as firmicutes. The use of soil microbial DNA testing could open the doors to more interpretation of information to eventually be on par with the forensic use of biological DNA testing which could potentially supplement testimonies on assumed burial locations that occurs frequently in criminal cases of body relocation and reburial.
ContributorsMata Salinas, Jennifer (Author) / Marshall, Pamela (Thesis director) / Bolhofner , Katelyn (Committee member) / Wang, Yue (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Natural Sciences (Contributor) / School of Humanities, Arts, and Cultural Studies (Contributor)
Created2022-05