Research has shown that 3 to 4-month-olds with female primary caregivers show visual preferences for female relative to male faces (Quinn, Yahr, Kuhn, Slater, & Pascalis, 2002). Facial experience is likely an important influence on these preferences. From birth, infants' experiences guide face-processing skills. This processing ability influences the development of efficient face recognition later in life. This early pattern of categorization aids in deciphering people and may have long lasting implications regarding face processing. These categorization skills may be a precursor to stereotyping later in life, so understanding how these skills develop and influence an infant’s understanding of their social world is an important area of research. The following study investigated (1) How visual preferences are influenced by real world experience with males and females, and (2) How experience affects older infants' visual preferences (i.e., 10-month-olds). To answer these queries, we tested 10-month-old Swedish infants because Sweden's public policy encourages male caregiving, therefore providing an ideal location to examine infants with a wide range of experience with male and female faces. Infants were recruited via email from a database of eligible infants at Uppsala Universitet. We asked parents to assess detailed interactions between their infant and other individuals for a period of seven days and examined visual interest toward male and female faces in the lab setting. Results indicated that the more time infants spent with non-caregiver females, the less time infants spent looking at the female faces. This pattern of preferences indicates that as infants master processing details of the female face, their attention shifts to the male face, and so begins the process of mastery in that regard. 

The circadian system generates daily oscillations of behavior and physiology including the sleep-wake cycle, rhythms of mood and hormonal release. These oscillations represent a predictable source of variance for neural centers that generate specific motor programs such as walking or hand movements. How and where in the brain this internal 24-h information is integrated to achieve effective motor patterns remains unknown. I hypothesized that the mouse primary motor cortex (PMC), a region responsible for complex motor programs, would show a signature of electrical activity associated with wheel running. I also hypothesized that this wheel running-associated electrical activity pattern would change predictably across the circadian cycle. I implanted electrocorticographic (ECoG) electrodes onto the PMC of mice and recorded brain wave activity while mice ran on the wheel at different circadian times. My results indicate a broad-spectrum power increase in the frequency of PMC electrical signals associated with wheel running. Furthermore, the spectrum frequency associated with wheel running changes predictably throughout the circadian cycle. My results provide a new model system in the use of ECoG in mice to assess circadian components associated with complex behaviors. It sheds new light on neural motor-system control, and it may have immediate application for the design of brain-computer interface devices that can operate accurately throughout the 24-h day.

Underground structures are important in civil infrastructure in modern urban areas to address the growing need for space. They are used in a wide range of engineering applications including building foundations, underground transportation systems, and underground storage facilities. These shallow structures typically require soil excavation from the ground surface. Thus, stability of the excavated ground is a major challenge in the design and construction processes. Bracing approaches have been implemented in the current state-of-practice to ensure the safety of the excavation. One common “Braced Excavation” system involves vertical retaining walls on both sides of the excavated ground held in place using horizontal internal struts. These struts are designed using Peck’s method of pressure distribution envelopes, which considers the strength of the material (i.e. soil and steel) and soil lateral pressures. However, due to uncertainties involved in the material properties and estimation of the soil pressure, the design internal strut loads tend to be higher than the internal strut loads seen in real-world situations. The objective of the research was to compare the induced internal forces on the laterally resisting struts in a braced excavation system found by using Peck’s Method, and measured internal strut loads using centrifuge physical modeling. A target prototype braced excavation system was defined and designed based on Pecks method of pressure distribution envelopes. Then, a scaled physical model was constructed and employed to simulate the prototype system in a geotechnical centrifuge. The insight gained through this project will be valuable in performance-based design engineering of underground structures. In addition, it will provide a comparative assessment of the efficiency of the design procedures, which eventually will lead to lower factors of safety.

Identifying the initiation and subsequent motion of thunderstorms along the Colorado Rocky Mountain Front Range continues to be a focal point in increasing forecast accuracy. There is sparse knowledge of the relationship between convection initiation (CI) and orographic (mountainous) precipitation with weak or strong synoptic scale forcing, or the level of atmospheric destabilization. Therefore, this leads to a low degree of forecast confidence due to the strong dependency of surface atmospheric conditions. CI can be referred to as the onset of thunderstorm activity due to atmospheric instability. We examine the various properties of CI, tying those ideas to cases where thunderstorms are generated by weak or strong synoptic scale forcing. Using archived radar data obtained from the National Climatic Data Center, a qualitative and quantitative representation of convective storm initiation patterns is made based on radar reflectivity observed between May and August of 2009 to 2012 between Denver and Fort Collins, Colorado, with each CI episode studied for a period of 4 hours. Thunderstorms used in the study were detected once the observed reflectivity of any given storm exceeded 35 dBZ. Locations of CI were also linked to topography as well as atmospheric conditions such as upper-level wind flow, surface winds, and moisture content (obtained primarily through the National Renewable Energy Lab archives) to determine thunderstorm characteristics and potential behavior given the initial conditions. Results show that convection develops along the Front Range and then migrates to the east in times of both weak and strong synoptic forcing. Depending on the wind direction, CI occurs on the north side of the Cheyenne Ridge and Palmer Divide for northerly flow and on the east side of the Rocky Mountains for easterly flow.

Understanding the energy expenditure required for the activities of daily living is a critical step in assessing the caloric needs both of those individuals whose body mass exceeds recommended standards and those who are chronically under/malnourished. Knowing how much energy people require to accomplish their activities of daily living, which typically includes walking with burdens (carrying excess weight) and on sloped surfaces, is a critical component in developing guidelines for appropriate caloric intake. Activity energy expenditure is the second largest component of daily energy use, after the energy required to maintain bodily function (usually called resting metabolic rate (RMR)). This study allows us to understand the relationship between burden, gradient and walking which is necessary to accurately account for the daily caloric needs of humans. To evaluate this relationship, data is collected from a large number of female participants. Participants walk at three self-selected velocities (slow, normal, and fast), on five gradients (flat, slight uphill and downhill at a gradient of (6.7%), and steep uphill and downhill at a gradient of (12.6%)) and two burdens (no burden and a burden of a 10 kg backpack).“Self-selected” velocity means that the subjects are able to choose their own pace, be it slow, normal or fast. This approach allows flexibility for the subjects to choose speeds that reflect their normal routine. The energy consumption is measured by the volumetric rate of oxygen consumption (VO2, inspiration) and carbon dioxide (VCO2, expiration) with a portable Cosmed K4b2 device. Unlike previous work that has used treadmills, this study is completed outside in an urban setting. Preliminary results indicate that walking outside requires different energy expenditure than walking on a treadmill. This study provides data collected from real-world experience, thereby providing more accurate understanding of the caloric needs to achieve more day-to-day activities.

Genome-Wide Association Studies (GWAS) determine the places in the genome where differences exist in the genetic sequences of individuals who have a disease as compared to a control group. Combining publicly available data from GWAS increases the ability to identify locations in the genome that may be shared by Autoimmune Diseases and thus share increased risk. It is well-known that many disease traits are polygenic and that it may actually be the smaller, combined contribution of many genes that influences risk and is therefore a better indicator of disease probability. Previously, I elicited the number of genes in common among autoimmune diseases, finding 32 genes associated with a cluster of five diseases and two clusters of two diseases each associated with 22 genes. Aware of the need for a rigorous analysis to determine whether these patterns are both novel and of statistical significance, I am developing multi-locus analytical methods to elicit the additive effects of each genetic location that may underlie the pathway toward disease development. To overcome single locus limitations, I am performing gene enrichment analysis on the genes that show these patterns to discover if single locations associated with these diseases are also associated with biochemical pathways and thus are of biological relevance. Finally, I am examining pair-wise analyses across the autoimmune diseases in question by using Biostatistics software packages such as Generalized Multifactor Dimensionality Reductions (GMDR). Continued identification and further characterization of genetic variants that may be causative for shared biochemical pathways and subsequent triggering of autoimmune diseases can be used to not only improve the health of those currently suffering by developing therapies that may be effective across multiple diseases, but also to develop targeted treatments designed to help prevent their development in those individuals who are genetically predisposed.