On the existence of infinitely many closed geodesics on orbifolds of revolution

Using the theory of geodesics on surfaces of revolution, we introduce the period function. We use this as our main tool in showing that any two-dimensional orbifold of revolution homeomorphic to S^2 must contain an infinite number of geometrically distinct closed geodesics. Since any such orbifold of revolution can be regarded as a topological two-sphere with metric singularities, we will have extended Bangert's theorem on the existence of infinitely many closed geodesics on any smooth Riemannian two-sphere. In addition, we give an example of a two-sphere cone-manifold of revolution which possesses a single closed geodesic, thus showing that Bangert's result does not hold in the wider class of closed surfaces with cone manifold structures.Comment: 21 pages, 4 figures; for a PDF version see http://www.calpoly.edu/~jborzell/Publications/publications.htm

Cross-sectional associations between variations in ankle shape by statistical shape modeling, injury history, and race : the Johnston County Osteoarthritis Project

Rheumatology Research Foundation Medical Student Preceptorship Award (Lateef/Nelson), NIAMS K23 AR061406 (Nelson); NIH/NIAMS P60AR064166 and U01DP003206 (Jordan/Renner), NIH/NIAMS R01AR067743 (Golightly). The funders had no role in study design; collection, analysis, or interpretation of data; writing the manuscript or the decision to submit for publication.Peer reviewedPublisher PD

Individual Differences in Personality Predict Externalizing Versus Internalizing Outcomes Following Sexual Assault

For some women, the experience of being sexually assaulted leads to increases in externalizing behaviors, such as problem drinking and drug use; for other women, the experience of being assaulted leads to increases in internalizing distress, such as depression or anxiety. It is possible that preassault personality traits interact with sexual assault to predict externalizing or internalizing distress. We tested whether concurrent relationships among personality, sexual assault, and distress were consistent with such a model. We surveyed 750 women just prior to their freshman year at a large public university. Consistent with our hypotheses, at low levels of negative urgency (the tendency to act rashly when distressed), sexual assault exposure had little relationship to problem drinking and drug use. At high levels of negative urgency, being sexually assaulted was highly associated with those externalizing behaviors. At low levels of internalizing personality traits, being assaulted had little relationship to depression and anxiety symptoms; at high levels of the traits, assault experience was highly related to those symptoms. Personality assessment could lead to more person-specific postassault interventions

An Exploration of Sexual Victimization and Academic Performance Among College Women

The literature has documented the widespread nature of sexual assault victimization among college women. While the aftermath of violence against university women has also received focus, that is, documenting trauma-related sequelae; risk factors; reporting patterns; and legal interventions, the impact on academic performance has not received adequate attention in the literature. The primary purpose of this study was to explore the association of rape and sexual assault with academic performance among college women. Its specific aims included the following: to compare high school and college sexual assault experiences with collegiate grade point averages (GPAs) at key points in time; to examine any differences in GPA by type of sexual assault; to urge researchers studying retention and persistence patterns or sexual assault among college students to ensure that the relationship between the two is included in research designs; and to recommend that academic institutions expand programming on retention to include rape and sexual assault among the risk factors associated with a lack of persistence

Global monopoles in dilaton gravity

We analyse the gravitational field of a global monopole within the context of low energy string gravity, allowing for an arbitrary coupling of the monopole fields to the dilaton. Both massive and massless dilatons are considered. We find that, for a massless dilaton, the spacetime is generically singular, whereas when the dilaton is massive, the monopole generically induces a long range dilaton cloud. We compare and contrast these results with the literature.Comment: 15 pages, 3 figures, version to appear in Class Quant Gra

The Effects of Climate Change on Interregional Electricity Market Dynamics on the U.S. West Coast

Abstract The United States (U.S.) West Coast power system is strongly influenced by variability and extremes in air temperatures (which drive electricity demand) and streamflows (which control hydropower availability). As hydroclimate changes across the West Coast, a combination of forces may work in tandem to make its bulk power system more vulnerable to physical reliability issues and market price shocks. In particular, a warmer climate is expected to increase summer cooling (electricity) demands and shift the average timing of peak streamflow (hydropower production) away from summer to the spring and winter, depriving power systems of hydropower when it is needed the most. Here, we investigate how climate change could alter interregional electricity market dynamics on the West Coast, including the potential for hydroclimatic changes in one region (e.g., Pacific Northwest (PNW)) to “spill over†and cause price and reliability risks in another (e.g., California). We find that the most salient hydroclimatic risks for the PNW power system are changes in streamflow, while risks for the California system are driven primarily by changes in summer air temperatures, especially extreme heat events that increase peak system demand. Altered timing and amounts of hydropower production in the PNW do alter summer power deliveries into California but show relatively modest potential to impact prices and reliability there. Instead, our results suggest future extreme heat in California could exert a stronger influence on prices and reliability in the PNW, especially if California continues to rely on its northern neighbor for imported power to meet higher summer demands

Nucleotide Frequencies in Human Genome and Fibonacci Numbers

This work presents a mathematical model that establishes an interesting connection between nucleotide frequencies in human single-stranded DNA and the famous Fibonacci's numbers. The model relies on two assumptions. First, Chargaff's second parity rule should be valid, and, second, the nucleotide frequencies should approach limit values when the number of bases is sufficiently large. Under these two hypotheses, it is possible to predict the human nucleotide frequencies with accuracy. It is noteworthy, that the predicted values are solutions of an optimization problem, which is commonplace in many nature's phenomena.Comment: 12 pages, 2 figure

Nonsuicidal Self-injury as a Risk Factor for Purging Onset: Negatively Reinforced Behaviours that Reduce Emotional Distress

Both nonsuicidal self-injury (NSSI) and purging behaviour are thought to involve harm to the self. The acquired capability for self-harm model holds that engaging in one self-harming behaviour increases the capability to tolerate harm to the self, thus increasing risk for engaging on other such behaviours. In addition, both behaviours are thought to serve the similar function of relief from distress. We thus tested whether engagement in one of these behaviours predicts the subsequent onset of the other. In a longitudinal design, 1158 first-year college women were assessed for purging and NSSI at two time points. Engagement in NSSI at time 1 predicted the college onset of purging behaviour 9 months later (OR = 2.20, p \u3c .04, CI = 1.07-4.19) beyond prediction from time 1 binge behaviour, and purging behaviour at time 1 predicted the subsequent onset of NSSI (OR = 6.54, p \u3c .01, CI = 1.71-25.04). These findings are consistent with the acquired capability for harm model and with the possibility that the two behaviours serve a similar function

P4‐154: The Protein Quality Control Protein, Ubiquilin‐2, Regulates Tau Accumulation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152960/1/alzjjalz2019063816.pd