The Bees of A.L. Mangham Jr. Regional Airport, Nacogdoches, Texas

The United States is home to about 4,000 species of native bees, and many are critically important due to the pollination services they provide (Buchman & Nabhan 1996). Most of these are inconspicuous, solitary bees that nest in the ground. In recent years, a number of bee species have been shown to be in decline (Burkle 2013). Due to these declines, it is important to study and provide habitat for local bee populations. As a result of periodic mowing, the surroundings of the A.L. Mangham Jr. Regional Airport in Nacogdoches County, Texas provide a grassy, prairie-like habitat that results in a high diversity of wildflowers. This site may contain high bee diversity as well. In order to explore this possibility, a survey of bees at this location was conducted in the late summer and fall of 2016

The Possible Interstellar Anion CH2CN-: Spectroscopic Constants, Vibrational Frequencies, and Other Considerations

It is hypothesized that the A ^1B_1 <- X ^1A' excitation into the dipole-bound state of the cyanomethyl anion (CH2CN-) is proposed as the carrier for one diffuse interstellar band. However, this particular molecular system has not been detected in the interstellar medium even though the related cyanomethyl radical and the isoelectronic ketenimine molecule have been found. In this study we are employing the use of proven quartic force fields and second-order vibrational perturbation theory to compute accurate spectroscopic constants and fundamental vibrational frequencies for ^1A' CH2CN- in order to assist in laboratory studies and astronomical observations

A comparison of bullying in public and private schools in a small Midwestern community

Little attention has been given to the possible differences in bullying at private and public schools. Little significant research exists on bullying at private schools, its characteristics, and its differences from public schools. Inattention to this segment of the population can lead to broad and inappropriate generalizations that what works in public schools will work in private schools. This dissertation investigated to what degree there were differences between the number of incidences, types of bullying, and locations of bullying that took place at a public and private school in a small Midwestern community. The research examined the following factors and their relationship to bullying: gender, faith affiliation, number of years in residence in the current school system, race, and the socio-economic status of the school. The methodology used to answer these questions was a quantitative based study where 412, sixth through eighth grade students from one public and one private school were surveyed about bullying. Five research questions guided the focus of this dissertation: (1) How many bullying incidences occur in both public and private schools? (2) What types of bullying activities take place in both public and private schools (Physical, verbal, cyber-bullying, etc.)? (3) Where does bullying occur within private and public school buildings and campuses? (4) To what degree are there differences between the number of incidences, types, and locations of bullying that take place at public and private schools? (5) How do traits such as gender, faith affiliation, number of years in residence in the current school system, and race relate to participation in bullying behaviors (Prevalence, type, and location of bullying)? Within the limits of the study, the following conclusions were reached: (1) No statistically significant difference existed between the amount of bullying at the public and private school. (2) A statistically significant difference did exist in some types of bullying between the public and private school. (3) When comparing the two school systems a statistically significant difference did exist in some specific locations where bullying occurred. (4) A variety of relationships existed between certain student characteristics and the survey questions. (5) The lack of a statistically significant difference in the amount of bullying that occurred at the public and private school allows educators to apply research findings from public schools research to private schools within the parameters of this research

Sum Rates, Rate Allocation, and User Scheduling for Multi-User MIMO Vector Perturbation Precoding

This paper considers the multiuser multiple-input multiple-output (MIMO) broadcast channel. We consider the case where the multiple transmit antennas are used to deliver independent data streams to multiple users via vector perturbation. We derive expressions for the sum rate in terms of the average energy of the precoded vector, and use this to derive a high signal-to-noise ratio (SNR) closed-form upper bound, which we show to be tight via simulation. We also propose a modification to vector perturbation where different rates can be allocated to different users. We conclude that for vector perturbation precoding most of the sum rate gains can be achieved by reducing the rate allocation problem to the user selection problem. We then propose a low-complexity user selection algorithm that attempts to maximize the high-SNR sum rate upper bound. Simulations show that the algorithm outperforms other user selection algorithms of similar complexity.Comment: 27 pages with 6 figures and 2 tables. Accepted for publication in IEEE Trans. Wireless Comm

Nonlinear Semi-Analytic Method for Spacecraft Navigation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77318/1/AIAA-2006-6399-190.pd

Nonlinear Mapping of Gaussian Statistics: Theory and Applications to Spacecraft Trajectory Design

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76930/1/AIAA-20177-363.pd

Dysregulation of visual motion inhibition in major depression

Individuals with depression show depleted concentrations of the inhibitory neurotransmitter GABA in occipital (visual) cortex, predicting weakened inhibition within their visual systems. Yet, visual inhibition in depression remains largely unexplored. To fill this gap, we examined the inhibitory process of centersurround suppression (CSS) of visual motion in depressed individuals. Perceptual performance in discriminating the direction of motion was measured as a function of stimulus presentation time and contrast in depressed individuals (n¼27) and controls (n¼22). CSS was operationalized as the accuracy difference between conditions using large (7.5°) and small (1.5°) grating stimuli. Both depressed and control participants displayed the expected advantage in accuracy for small stimuli at high contrast. A significant interaction emerged between subject group, contrast level and presentation time, indicating that alterations of CSS in depression were modulated by stimulus conditions. At high contrast, depressed individuals showed significantly greater CSS than controls at the 66 ms presentation time (where the effect peaked in both groups). The results' specificity and dependence on stimulus features such as contrast, size and presentation time suggest that they arise from changes in early visual processing, and are not the results of a generalized deficit or cognitive bias.Accepted versio