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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 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
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There are unrealistic expectations of the forensic science discipline by the public today. More specifically about the types of evidence that can be recovered from a fired cartridge casing. The common misconception with the evidence that can be recovered from a cartridge casing is that all three types of evidence:

There are unrealistic expectations of the forensic science discipline by the public today. More specifically about the types of evidence that can be recovered from a fired cartridge casing. The common misconception with the evidence that can be recovered from a cartridge casing is that all three types of evidence: DNA, latent prints, and firearms can be recovered from the same cartridge casing. However, just because some analyses are possible does not mean that they are practical. The definition of possibility is that an event can happen. However, the definition of practicality is not only that it can happen, but that the event should occur to optimize the efficiency of a given task. Through literature review of previous studies as well as experimental data, each discipline (DNA, latent prints, and firearms and toolmark analysis) were evaluated. For the experimental trials, three total experiments were carried out. Experiment one focused on the possibility aspect, so in experiment one the best conditions were simulated to receive a positive result. Experiment two focused on creating conditions that would occur at a crime scene, and experiment three refined those variables to serve as middle ground. After evaluation, each discipline was classified as possible and/or practical. These results were then used to determine practical sequential processing for a fired cartridge casing. After both experimentation and review, it was determined that the best possible sequential processing path for a cartridge casing collected at the crime scene to get the quickest information back is as follows: Firearms, DNA, Latent Prints.
ContributorsKephart, Amanda K. (Author) / Armendariz Guajardo, Jose (Thesis director) / Kobojek, Kimberly (Committee member) / Rex, Scott (Committee member) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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Description

Medicolegal forensic entomology is the study of insects to aid with legal investigations (Gemmellaro, 2017). Insect evidence can be used to provide information such as the post-mortem interval (PMI). Blow flies are especially useful as these insects are primary colonizers, quickly arriving at a corpse (Malainey & Anderson, 2020). The

Medicolegal forensic entomology is the study of insects to aid with legal investigations (Gemmellaro, 2017). Insect evidence can be used to provide information such as the post-mortem interval (PMI). Blow flies are especially useful as these insects are primary colonizers, quickly arriving at a corpse (Malainey & Anderson, 2020). The age of blow flies found at a scene is used to calculate the PMI. Blow fly age can be estimated using weather data as these insects are poikilothermic (Okpara, 2018). Morphological analysis also can be used to estimate age; however, it is more difficult with pupal samples as the pupae exterior does not change significantly as development progresses (Bala & Sharma, 2016). Gene regulation analysis can estimate the age of samples. MicroRNAs are short noncoding RNA that regulate gene expression (Cannell et al., 2008). Here, we aim to catalog miRNAs expressed during the development of three forensically relevant blow fly species preserved in several storage conditions. Results demonstrated that various miRNA sequences were differentially expressed across pupation. Expression of miR92b increased during mid pupation, aga-miR-92b expression increased during early pupation, and bantam, miR957, and dana-bantam-RA expression increased during late pupation. These results suggest that microRNA can be used to estimate the age of pupal samples as miRNA expression changes throughout pupation. Future work could develop a statistical model to accurately determine age using miRNA expression patterns.

ContributorsHerrera-Quiroz, Demian David (Author) / Parrott, Jonathan (Thesis director) / Weidner, Lauren (Committee member) / School of Mathematical and Natural Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

Forensic entomology is an important field of forensic science that utilizes insect evidence in criminal investigations. Blow flies (Diptera: Calliphoridae) are among the first colonizers of remains and are therefore frequently used in determining the minimum postmortem interval (mPMI). Blow fly development, however, is influenced by a variety of factors

Forensic entomology is an important field of forensic science that utilizes insect evidence in criminal investigations. Blow flies (Diptera: Calliphoridae) are among the first colonizers of remains and are therefore frequently used in determining the minimum postmortem interval (mPMI). Blow fly development, however, is influenced by a variety of factors including temperature and feeding substrate type. Unfortunately, dietary fat content remains an understudied factor on the development process, which is problematic given the relatively high rates of obesity in the United States. To study the effects of fat content on blow fly development we investigated the survivorship, adult weight and development of Lucilia sericata (Meigen; Diptera: Calliphoridae) and Phormia regina (Meigen; Diptera: Calliphoridae) on ground beef with a 10%, 20%, or 27% fat content. As fat content increased, survivorship decreased across both species with P. regina being significantly impacted. While P. regina adults were generally larger than L. sericata across all fat levels, only L. sericata demonstrated a significant (P < 0.05) difference in weight by sex. Average total development times for P. regina are comparable to averages published in other literature. Average total development times for L. sericata, however, were nearly 50 hours higher. These findings provide insight on the effect of fat content on blow fly development, a factor that should be considered when estimating a mPMI. By understanding how fat levels affect the survivorship and development of the species studied here, we can begin improving the practice of insect evidence analysis in casework.

ContributorsNoblesse, Andrew (Author) / Weidner, Lauren (Thesis director) / Parrott, Jonathan (Committee member) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description

The field of forensic science has been growing and changing with improvements in DNA analysis. One field affected is forensic entomology, which is exploring many ways in which DNA can increase the application of insects in forensic science. One application being explored is the use of insects as a source

The field of forensic science has been growing and changing with improvements in DNA analysis. One field affected is forensic entomology, which is exploring many ways in which DNA can increase the application of insects in forensic science. One application being explored is the use of insects as a source of human DNA in a criminal investigation. Using flies as a source of foreign DNA can also be utilized in ecological research to conduct surveys on the various species present in different environments. This experiment intends to determine if flies can act as a viable source of alternate DNA. This will be accomplished by an ecological survey of DNA extracted from flies. DNA extractions were performed on flies gathered from parts of the greater Phoenix area. The DNA was then amplified with primers targeting different animal species and examined to observe what animals the flies had come in contact with. Several samples had contamination due to human error and were not able to be evaluated. One DNA extraction out of fifteen yielded pig DNA, indicating flies can be used as a source of DNA. Future experiments should use different animal primers and amplify sections of DNA that can determine the different species consumed by flies. Further research into flies as a DNA source can increase the amount of information available to forensic scientists as well as improve ecologist’s observation of an environment’s biodiversity.

ContributorsRiccomini, Brianna (Author) / Parrott, Jonathan (Thesis director) / Marshall, Pamela (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Natural Sciences (Contributor)
Created2023-05
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Description
Forensic entomology is the use of insects in legal investigations, and relies heavily upon calculating the time of colonization (TOC) of insects on remains using temperature-dependent growth rates. If a body is exposed to temperatures that exceed an insect’s critical limit, TOC calculations could be severely affected. The determination of

Forensic entomology is the use of insects in legal investigations, and relies heavily upon calculating the time of colonization (TOC) of insects on remains using temperature-dependent growth rates. If a body is exposed to temperatures that exceed an insect’s critical limit, TOC calculations could be severely affected. The determination of critical thermal limits of forensically-relevant insects is crucial, as their presence or absence could alter the overall postmortem interval (PMI) calculation. This study focuses on the larvae of Phormia regina (Meigen) (Diptera: Calliphoridae), a forensically relevant blow fly common across North America. Three populations were examined (Arizona, Colorado, and New Jersey), and five day old larvae were exposed to one of two temperatures, 39℃ or 45℃, for five hours. Across all colonies, the survival rate was lower at 45℃ than 39℃, in both larval and emerged adult stages. The Arizona colony experienced a harsher drop in survival rates at 45℃ than either the Colorado or New Jersey colonies. This research suggests that the range of 39℃ - 45℃ approaches the critical thermal limit for P. regina, but does not yet exhibit a near or complete failure of survivorship that a critical temperature would cause at this duration of time. However, there is opportunity for further studies to examine this critical temperature by investigating other temperatures within the 39℃ - 45℃ range and at longer durations of time in these temperatures.
ContributorsMcNeil, Tara (Author) / Weidner, Lauren (Thesis director) / Meeds, Andrew (Committee member) / Barrett, The Honors College (Contributor) / School of Humanities, Arts, and Cultural Studies (Contributor) / School of Mathematical and Natural Sciences (Contributor)
Created2022-05