Instars: A Journal of Undergraduate Research (Texas Digital Library - TDL E-Journals)
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The Preference of Common Ant Species to Natural and Artificial Sugars Found in Beverages
No full textAbstract: The species selected to be surveyed are the common pest ants of non-forested areas in Texas: Solenopsis invicta, Camponotus sp., Atta texanus, Tapinoma sessile, Tapinoma melanocephalum, Solenopsis molesta, Dorymyrmex sp., Monomorium pharaonis, Prenolepis imparis, Paratrechina longicornis, Labidus coecus, Crematogaster sp., Pogonomyrmex barbatus, Tetramorium bicarinatum, Pheidole dentata. Ant affinity for five different liquids containing different sugars was tested: water, sugar water (sucrose), Stevia (aspartame), apple juice (fructose), and Coca-Cola (high fructose corn syrup, glucose, manufactured fructose). Traps were set in five different, non-forest locations in Bryan/College Station, Texas to determine to which types of sugars the ants most gravitated. Based on previous experiments and conclusions, it was hypothesized that ants had adapted to equally favor all varieties of sugar found in conventional beverages. The variety of ants that were trapped in experimentation were: red imported fire ants (Solenopsis invicta), carpenter ants (Camponotus vicinus), thief ants (Solenopsis molesta), pharaoh ants (Monomorium pharaonis), acrobat ants (Crematogaster sp.), and ghost ants (Tapinoma melanocephalum). Not all ant species that were planned to be surveyed were collected. From the ants obtained, it was determined which liquid tested for was most frequented, and by which types of ants. A conclusion was made that ants do have a preference in sugar type, which contradicted the original hypothesis of the researchers.
Comparison of Forensic Evidence and Eyewitness Testimony Accuracy and Reliability
No full text
Abstract: In this experiment, the accuracy of forensic evidence and eyewitness testimony is investigated through a group of participants to generalize how the public feels about forensic evidence and eyewitness testimony to explore the reasoning and continued use of eyewitness testimony which may be ultimately less accurate than forensic evidence. Given the first survey, the participants answer if they find forensic evidence or eyewitness testimony more accurate or reliable, which forensic method they find most accurate out five choices, and then asked to describe what they saw in a video. Given the second and last survey, participants are asked to identify a suspect based on the original video. Then depending on the response, participants were asked to answer if they would be willing to change their mind if forensic evidence was found that contradicts their choice. It was found that 95.5% of participants found forensic evidence more accurate, the majority found DNA analysis to be the most accurate method, and 85% of those that picked a suspect from the line up would consider that their memory was flawed or a mistake had been made if DNA analysis contradicted their choice. Forensic evidence was found to be the most accurate and the majority of participants were willing to go back on their eyewitness testimony given forensic evidence that provides a differing solution, meaning that the accuracy of eyewitness testimony is not perceived as being above forensic evidence and the use of eyewitness testimony in court and elsewhere should be cautiously approached.
 
Commensalism in Necrophagous Arthropods May Lead to the Discovery of Clandestine Burials
No full textToday, uncovering illicitly buried persons in homicide cases usually involves ground-penetrating radar and other electronic resistivity methods, and for emergency situations that is unlikely to change. However, taking advantage of what is visible above ground could reveal probative information regarding reduced fields of search of suspected areas. Insects are the most species-rich group of animals on the planet and many species of insect have the ability to dwell above and below ground. Ants, for example, can build nests that are sizeable enough to be noticed above ground but may also extend deep beneath the surface. In this study, insects were surveyed from sites that were designed to mimic clandestine burials related to homicide. Chicken bait was buried over a foot deep and left to decay for several days in a warm, forested area, near areas of noticeable ant activity. Daily observations and identification of insects on the ground surface directly over the burial site were conducted. Ants were the most prevalent at each site, however, they were also the most difficult to discern from far distances. Flies were easily discernable from up to distances of 27 ft, on average, but were only available after colonization of the carrion done by ants. Given these results, it is likely that necrophagous arthropods can be used to aid in the discovery of clandestine burials
The Effect of the Presence of Iron in Common Household Substances on the Luminol Blood Detection Test
No full textAbstract: Forensic science encompasses a multitude of different sub-disciplines. One of these is crime scene investigation, in which investigators collect and analyze evidence found at crime scenes. Blood is a critical piece of evidence found at crime scenes, it can provide investigators with a wealth of information about the case. Luminol is one of the most frequently used presumptive blood tests and determines if a substance may be blood or not. When luminol comes into contact with the hemoglobin in blood, it produces chemiluminescence because of an oxidation reaction. There are some substances that are known to produce false-positives for the luminol test, these include strong oxidants and true peroxidases. This study focused on the presence of iron in the substances tested and whether the iron would produce a false-positive. Half of the substances tested contained iron and the other half didn’t. The substances containing iron didn’t produce a higher level of fluorescence than the substances not containing iron. The results don’t support the assumption that the presence of iron in a substance would affect its fluorescence when sprayed with luminol
Victoria’s Secret Bombshell Perfume’s Effectiveness as Aedes aegypti (Linnaeus) (Diptera: Culicidae) Mosquito Repellent
No full textThere are many vector-borne diseases that mosquitoes spread which pose risks for human health. Different repellents have been formulated to prevent interactions between the host and the vector. In this experiment, Victoria’s Secret Bombshell perfume was evaluated as a repellent of Aedes aegypti (Linnaeus) (Diptera: Culicidae) by comparing it to DEET (N,N-Diethyl-meta-toluamide). The mean number of bites on arms wearing DEET, perfume, and nothing were determined and compared with one another. DEET was observed to prevent the most Aedes aegypti bites whereas the perfume did not prevent as many but did prevent more than the arms with nothing on
Comparison of Fingerprints Between Genders
No full textFingerprints are some of the most common sources of physical evidence in forensic science. This study examined the differences and similarities between fingerprints of different sexes to determine if it is possible to infer the sex of a person based on their fingerprint. Participants in this study included students, males and females between the ages of 18-24. Participants were sent out a form which consisted of instructions on how to take their own fingerprints and questions such as their age and sex. These fingerprints were then analyzed for the pattern, number of ridges and other unique features. It was observed that factors such as ridge density, ridge count, size of the print differ between genders. This led to the conclusion that fingerprints found in crime science investigations can be compared to fingerprints in databases in order to identity these factors and help infer the gender of the person associated with the print
Putrefaction Impact of Bivariate Differences in Decomposition Environments: Substantiated through a Plastic Tarp
No full textThe use of a plastic tarp to dispose of a dead body is portrayed frequently in true crime media and often seen in actual investigated murder cases. In these instances, the suspect wraps a victim\u27s body completely in a plastic tarp and disposes of it, hoping that because the remains are not actively exposed, they will not be discovered. This paper explores the differences between a natural, open decomposition and a closed decomposition in which the body is wrapped in a plastic tarp and analyses the effectiveness of utilizing a plastic tarp for body disposal. Using two wild Texas hogs, Sus Scrofa, as surrogates for human bodies, the decomposition process was monitored biweekly for ten weeks. The temperature, moisture level, insect presence, animal activity, and overall condition of the bodies were measured to determine which decomposition process occurred at a quicker rate and what factors of decomposition had the greatest effect on the rate at which the bodies reached Butyric Fermentation. While the pig wrapped in the tarp underwent faster internal decomposition changes, the presence of increased insect and animal activity to the exposed pig caused its body to deteriorate faster. Therefore, it can be determined that while, in a theoretical, concealed environment, a plastic tarp would be a more effective method to decompose a body because the tarp holds the victim at higher internal temperatures and accumulates moisture. However, because of the importance of insect and animal activity in the decomposition process, leaving a body without covering would help eliminate and scatter the bodily evidence faster and more effectively.
Key Words: Decomposition, Forensic Taphonomy, Forensic Entomolog
Fingerprint Patterns: Genetic or Random?
No full textAbstract: Fingerprints are used for identification in both legal and civil matters. Their use ranges from forensic evidence to identification for important documentation such as a driver’s license. The patterns of friction ridge skin are varied throughout the population with a majority having loops and very few having arches. The aim of this study was to determine the predictability of pattern types and determine if they have genetic significance. The results from this experiment showed that overall pattern types are genetically inherited while distinctive minutiae are due to random environmental stimuli.
Keywords: identification, minutiae, genetic, friction ridge ski
The Effects of Witness Bias on the Identification of Perpetrators within a Photo Lineup
No full textThroughout the history of forensic science, the questioning of the reliability of eyewitness testimony and suspect identification has been prevalent. The purpose of this experiment is to determine the extent to which race affects the results of identifying a suspect in a photo lineup. This experiment particularly aims to determine how cross-race-effect impacts the accuracy of eyewitness identification. This study was carried out by setting up a mock crime with various mock witnesses and suspects. The witnesses were shown a picture of two perpetrators escaping the crime for approximately 20-30 seconds. The mock witnesses were instructed to note down any key characteristics to identify these suspects. After several weeks, the witnesses were sent out an online survey in which they are presented with two photo-lineups. One photo-lineup consisted of suspects from the same ethnic background as the majority of the witnesses and one photo lineup of suspects from a different background from the witness. It should be noted that some witnesses were not of the same ethnic background as either perpetrator. These photo lineups also consisted of cumulative descriptions of what the mock witnesses provided earlier in the experiment. The witnesses were then asked to identify the correct perpetrator from the lineup using this information. It was found that the majority of the mock witnesses accurately identified the perpetrators. However, the witnesses tend to identify the incorrect suspect when the suspect was of a different ethnic background than the witness. This finding is interesting as it implies that race impacts the reliability of eyewitness testimony.
 
The Ability to Affect the Results of a Phenolphthalein Test with Household Chemicals
No full textThe detection of blood at a crime scene can yield great progress for an investigation. The presence of the bodily fluid can lead to the knowledge of whether the blood is in fact human, the amount of people that were present at the scene, and lead to DNA analysis being done and obtaining the identity of which the blood belongs to. A component in blood, hemoglobin, can break down hydrogen peroxide, making the protein a great focus for presumptive blood tests. For this experiment, a few household chemicals were used to test their ability to tamper with a color indicator Phenolphthalein Test. If the swab turned pink rapidly, this meant the stain came back positive for blood. If no color change occurred, the test could not detect if the substance swabbed was blood. Results obtained showed that household products with certain chemicals and percentage of said chemicals can be used denature the composition of hemoglobin in bloodstains