Tag: Jeanne McLaughlin

Asymmetry of the Dental Arcade in Six Populations from the Indian Sub-Continent 

Presenter(s): Aimee Herubin − Anthropology

Faculty Mentor(s): Jeanne McLaughlin, Frances White

Poster 76

Research Area: Physical science

Deviations from symmetry that arise during development are defined as fluctuating asymmetry (FA). Greater asymmetry is often related to differences in genetic and environmental factors experienced during development with males showing more asymmetry than females. We measured FA in human dental arcades from different Indian social castes. We hypothesized that men and women would have differing degrees of asymmetry as well as individuals in different castes. We measured samples from the John R. Lukacs Dental Cast Collection at the University of Oregon. Our sample consisted of 177 paired mandibles and maxillae (57 females, 120 males). Individuals were from one of six social castes. Permanent dentition was measured in a three-dimensional plane at the cervix between the first incisors and on the distal surface of premolars and molars. 13 landmarks were digitized using a microscribe-3DX© following the protocol of Frost et al (2003). Dental FA was measured by calculating the Procrustes’ distance between each individual and its mirror image. We compared mean asymmetry by sex and caste using a two-way ANOVA. We found significant differences in both the maxilla and mandible FA between castes (F=51.28, DF=5, p<0.0001 and F=19.40, DF=5, p<0.0001, respectively) but not between sexes with no significant interaction term. Our hypothesis that there would be a difference in asymmetry between sexes was not supported, however, our hypothesis that there would be differences in levels of asymmetry between castes was supported. This suggests that there may be genetic or environmental factors influencing dental arcade development differently in different castes.

Preliminary Decomposition Study within the Willamette Valley of Oregon: Multi-Regional Comparison and Sharp Force Trauma Effects

Presenter(s): Cheyenne Collins − Anthropology

Faculty Mentor(s): Jeanne McLaughlin

Poster 132

Research Area: Social Science

Funding: Extraordinary Expense Thesis Research Grant from the Robert D. Clark Honors College
Ronald E. McNair Scholars Program

Determining time since death (post-mortem interval or PMI) is an essential part of medico-legal death investigations. PMI can give investigators important information about time of death and may help answer questions about the events leading up to death. The purpose of this study is to collect decompositional data from an understudied region (Oregon), and compare these data to better studied regions such as Tennessee, in order to characterize the effects of regional variation on decomposition and taphonomy. Six pig heads will be exposed to the natural environment in the Willamette Valley of Oregon for sixty days. Three of these pig heads will undergo sharp force trauma infliction (SFT) in order to compare rate of decay with remains that have a singular SFT wound. Stage of decomposition, temperature, precipitation, and preliminary entomological data will be collected throughout the sixty-day observation period. These data will be used to calculate Accumulated Degree Days (ADD); evaluate variation between similar studies involving different North American regions; compare and contrast similar studies within the Willamette Valley of Oregon; and analyze the effects of sharp force trauma (SFT) on decomposition rates and insect activity.

Preliminary Identification of fungi presenting on the surface of decomposing porcine heads

Presenter(s): Jennifer Nelson

Faculty Mentor(s): Jeanne McLaughlin

Poster 24

Session: Sciences

Taphonomy is the study of events and processes that affect remains of an organism after death. It is an essential component of medico-legal death investigations and can be used to reconstruct the events leading up to the death as well as time since death. Although fungus is a known decomposer, very little research has been published in relation to the identification and morphology of fungi found on decomposing flesh, which is a potential source of data for estimation of PMI (post mortem interval). The purpose of this study is to identify and indicate the morphology of the fungi found on three Sus scrofa (pig) heads, as pigs are a commonly used proxy for human cadavers in the field of forensic taphonomy. Skin samples with visible fungal growth were taken from the heads of three separate pigs in the same outdoor enclosure, however, each head has exposure to differing amounts of sunlight. Methodology for identification includes culture media for growth and microscopic examination to identify and compare morphological features. The identification of numerous different fungi and growth patterns on decomposing flesh may be useful as an independent line of evidence for establishing PMI and gain ecological information regarding a scene. There has been limited attempts to identify saprophytic fungi on decomposing flesh, and none to this researcher’s knowledge in the Pacific Northwest. This study attempts to identify potentially significant species for further study.

Primary results pending.

Primary conclusion pending.

Significance pending.

Early Observational Data on Arthropods Associated with Winter Decomposition in the Pacific Northwest

Presenter(s): Brittany Falconer

Faculty Mentor(s): Jeanne McLaughlin

Poster 65

Session: Sciences

Forensic Entomology plays an important role within the field of medicolegal death investigations. By studying the presence of certain arthropod species, scientists are able to provide an estimate of post-mortem interval (PMI), or how long an individual has been deceased, for a set of remains in question. This estimate of PMI is based on a known set of growth, development, and succession patterns for necrophagous and predatory arthropods that are associated with remains. Though forensic entomology provides important information for forensic investigators, there are a multitude of factors that can affect succession patterns. Geographic location and temperature are two big factors that can influence how arthropods behave. In a separate research project studying winter decomposition rates using pig heads, insect activity appeared to contradict previously known arthropod succession rates and temperature thresholds. Arthropods exhibit a lower thermal limit, sometimes called a critical thermal minimum, which affects their activity in lower temperatures. Within the research site, maggot activity was present throughout the cold winter temperatures, many days well below freezing. Additionally, female flies needing to lay eggs tend to appear on decomposing remains first, then necrophagous and predatory beetles follow after. The first arthropods observed on the remains were beetles, contradictory to previous observations. Geographic location also influences the behavior of certain species of arthropods and could affect how the arthropods within the research site were behaving.

Starting a Taphonomic Research Facility in the Willamette Valley of Oregon: a joint project between Lane Community College (LCC) and the University of Oregon (UO)

Presenter(s): Cheyenne Collins

Faculty Mentor(s): Jeanne McLaughlin

Oral Session 4 C

Poster 153

Session: Social Sciences & Humanities

Taphonomy is the study of events and processes that affect remains of an organism after death. It is an essential component of medico-legal death investigations and can aid in reconstructing events leading up to the death as well as time since death. The creation of the Anthropological Research Facility, aka “the body farm” in Tennessee changed how taphonomy was perceived and boosted taphonomic study into the field of forensic science through its focus on human decomposition. Recent research has called for more regional studies in order to test widely accepted methodologies in differing environments. The creation of this facility in the Willamette Valley has involved a multi-year effort gaining various institutional approvals, securing grant funding, and planning a pilot project that is the first of its kind in the region. This facility is one of less than ten facilities in the United States and the only one west of the Rocky Mountains. The conclusion of the facilities’ first project has secured a plethora of data on decomposition from this region, as well as yielded new data on animal scavenging, insect activity, and microorganisms. Multiple undergraduate research projects including both LCC and UO students have also stemmed from the pilot study. The incoming data has already demonstrated that additional regional studies are needed in the Willamette Valley, which is a taphonomically unique environment. This presentation will discuss the opening of this unique local outdoor research site, share a variety of the initial outcomes of the pilot project(s), and discuss future plans.