The Effect of Perceived Uncertainty on Competitive Behavior

How do people behave in the face of uncertainty? Some studies suggest that even when they are unaware of how others will behave, people default to cooperative behavior; however, other research suggests that uncertainty leads to more competitive behavior. Little research has examined how individual differences moderate such behavioral decisions. This study proposes that a stable (dispositional) sense of justice may, ironically, lead to more competitive behavior. Specifically, people who score highly in belief in a just world, system justification, and religiosity, and low in ambiguity tolerance may be more inclined to compete rather than cooperate because they believe people who experience positive outcomes deserve those outcomes regardless of the means taken to achieve them. Across two studies, participants (N = 288) engaged in a prisoner’s dilemma game — a task where they must choose to compete or cooperate — and completed the aforementioned individual difference measures. Results show that people tended to cooperate, but those high in system justification and belief in a just world were more likely to compete. In other words, people with a strong sense of cosmic justice were likely to exhibit competitive behavior under uncertain conditions. KEYWORDS: Ambiguity Tolerance; Competition; Cooperation; Just World Beliefs; Prisoner’s Dilemma; Prosocial Behavior; Religiosity; System Justification; Uncertainty

Factors Associated with Surgery Among South Asian American and Non-Hispanic White Women with Breast Cancer

South Asian American (SA) women are diagnosed with more aggressive breast cancer than non-Hispanic White (NHW) women. Understanding the factors associated with the types of surgery received by these women sheds light on disease management in these culturally distinct populations. We used data on age at diagnosis, stage, grade, estrogen and progesterone receptors, and surgery from 4,590 SA and 429,030 NHW breast cancer cases in the Surveillance, Epidemiology and End Results (SEER) program. We used logistic regression with surgery as the binary outcome (subcutaneous, total, or radical mastectomy (STRM) versus partial mastectomy, no, unknown or other (PNUM)) and included additive effects of all the variables and interactions of age, stage, grade, and estrogen and progesterone receptors with race/ethnicity. Type I error of 5% was used to assess statistical significance of the effects. SA were significantly more likely than NHW cases to receive STRM relative to PNUM surgery among women diagnosed at or after age 50 years and having localized stage disease (Odds Ratio (OR) = 1.27, 95% Confidence Interval (CI) = 1.06 – 1.52). Further, SA were significantly less likely than NHW cases to receive STRM relative to PNUM surgery among those diagnosed before age 50 years and having regional or distant stage disease (OR = 0.75, 95% CI = 0.59 – 0.95 for age at diagnosis < 40 years; OR = 0.77, 95% CI = 0.62 – 0.95 for age at diagnosis 40-49 years). The type of surgery received by SA and NHW women differ according to age at diagnosis and disease stage. KEYWORDS: Breast Cancer; Surgery; Cancer Health Equity; Disease Characteristics; South Asian American; Non-Hispanic White; Logistic Regression; Interaction

An Optimal Control Experiment for an SEIRS Epidemiological Model

This work studies an optimal control model for a discrete-time Susceptible/Exposed/Infective/Removed/Susceptible (SEIRS) deterministic epidemiological model with a finite time horizon and changing population. The model presented converts a continuous SEIRS model that would typically be solved using differential equations into a discrete model that can be solved using dynamic programming. The discrete approach more closely resembles real life situations, as the number of individuals in a population, the rate of vaccination to be applied, and the time steps are all discrete values. The model utilizes a previously developed algorithm and applies it to the presented SEIRS model. To demonstrate the applicability of the algorithm, a series of numerical results are presented for various parameter values. KEYWORDS: Control; Cost; Discrete; Disease; Epidemiology; Minimization; Modeling; Optimality; SEIRS; Vaccination

Do Warmups Predict Pole Vault Competition Performance?

The aim of this research was to determine the relationship between pole vault warmup and competition performance in a sample of 16 collegiate vaulters over 60 observations. Pole vault athletes are given time to warm up in the same area that the competition will take place. This prompted investigation into whether better warmup performance could indicate better familiarity with the performance environment, and whether this could translate to the competition. The number of warmup vaults taken was also considered. Participants were observed during multiple warmup periods and data was collected on warmup performance. The findings indicate a significant correlation between instances in which participants displayed their best warmup scores and their best competition performances, likewise with their worst. Also, participants who took more warmup vaults performed significantly better on average. Athletes and coaches should consider implementing warmup practices that emphasize familiarizing oneself with their performance environment. KEYWORDS: Pole Vault; Track and Field; Warmups; Warmup Performance; Competition Performance; Performance Environment; Nested Task; Task Constraints

On Packing Thirteen Points in an Equilateral Triangle

The conversation of how to maximize the minimum distance between points - or, equivalently, pack congruent circles- in an equilateral triangle began by Oler in the 1960s. In a 1993 paper, Melissen proved the optimal placements of 4 through 12 points in an equilateral triangle using only partitions and direct applications of Dirichlet’s pigeon-hole principle. In the same paper, he proposed his conjectured optimal arrangements for 13, 14, 17, and 19 points in an equilateral triangle. In 1997, Payan proved Melissen’s conjecture for the arrangement of fourteen points; and, in September 2020, Joos proved Melissen’s conjecture for the optimal arrangement of thirteen points. These proofs completed the optimal arrangements of up to and including fifteen points in an equilateral triangle. Unlike Melissen’s proofs, however, Joos’s proof for the optimal arrangement of thirteen points in an equilateral triangle requires continuous functions and calculus. I propose that it is possible to continue Melissen’s line of reasoning, and complete an entirely discrete proof of Joos’s Theorem for the optimal arrangement of thirteen points in an equilateral triangle. In this paper, we make progress towards such a proof. We prove discretely that if either of two points is fixed, Joos’s Theorem optimally places the remaining twelve. KEYWORDS: optimization; packing; equilateral triangle; distance; circles; points; thirteen; maximize

An Unbiased Mineral Compositional Analysis Technique for Circumstellar Disks

A circumstellar disk that surrounds a star is composed of gas, dust, and rocky objects that are in orbit around it. Around infant stars, this disk can act as a source of material that can be used to form planetesimals, which can then accrete more material and form into planets. Studying the mineral composition of these disks can provide insight into the processes that created our solar system. The purpose of this paper is to analyze the mineral composition of these disks by using a newly created python package, Min-CaLM. This package determines the relative mineral abundance within a disk by using a linear regression technique called non-negative least square minimization. The circumstellar disks that are capable of undergoing compositional analysis must have a spectrum with both a detectable mid-infrared excess and prominent silicate features. From our sample, there are only eight debris disks that qualify to be candidates for the Min-CaLM program. The mineral compositions calculated by Min-CaLM are then compared to the Tholen asteroid classification scheme. HD 23514, HD 105234, HD 15407A, BD+20 307, HD 69830, and HD 172555 are found to have a compositions similar to that expected for C-type asteroids, TYC 9410-532-1 resembles the composition of S-type asteroids, and HD 100546 resembles D-type asteroids. Min-CaLM also calculates the mineral compositions of the comets Tempel 1 and Hale-Bopp, and they are used as a comparison between the material in our early solar system and the debris disk compositions. KEYWORDS: Debris disk; Mineral; Composition; Analysis; Asteroid; Circumstellar; Spectroscopy; Python

A Narrative Literature Review of the Psychological Hindrances Affecting Return to Sport After Injuries

After different sports injuries, athletes may experience various psychological emotions in response to such injuries, which could lead an athlete to feel stressed. These emotions include anger, fear, frustration, anxiety, and depression which may lead to lack of confidence in returning to their sport and/or fear of sustaining a new injury. This narrative review aims to determine the possible psychological hindrances present when an athlete is planning on returning to sport after injury to an anterior cruciate ligament (ACL) or after sustaining a concussion. The synthesized information for this review has been collected from researching the databases PubMed, SportDiscus, PsycInfo, and Google Scholar using search terms including “return to sport”, “ACL injury”, “concussion”, and “psychology”. Journal articles needed to be in English and published in the years 2009-2019; books and unpublished abstracts were excluded. A total of 42 studies were included and analyzed using deductive coding to organize and synthesize relevant articles into themes. The review summarizes the shared common and the different psychological hindrances that may be found in athletes after an ACL injury or concussion. Shared psychological characteristics for returning to sport following either an ACL injury or concussion included fear, self-esteem, control, anxiety, stress, recovery, and social support. Discovering the common and unique psychological barriers which may affect the injured athletes from returning to sport can help educate athletes’ families, coaches, and healthcare professionals, as well as promote discussions for the future to help athletes feel more secure in their return to their respective sport. KEYWORDS: ACL Injuries; Concussions; Sport Injuries; Athletes; Narrative Literature Review; Psychological Hindrances; Psychological Characteristics; Return to Sport; Psychology

Enzymatic and Structural Characterization of Alanine Racemase from Enterococcus faecium by Kinetic and Computational Studies

The surge in vancomycin-resistant enterococci (VRE) strains poses a serious threat to public and clinical health. VRE strains are the leading cause of multi-drug resistant enterococcal infections and are commonly acquired from medical devices. Therefore, it is essential to discover new antibacterial targets and drugs for this pathogen. Alanine racemase could be a valuable drug target due to its crucial role in E. faecium survival. Alr from E. faecium (EF_Alr) was heterologously produced and purified from E. coli., and the steady-state kinetic constants were determined at different pH values. Using a coupled reaction with L-alanine dehydrogenase, rate of production of NADH was measured at 340 nm to observe EF_Alr activity in the D- to L-alanine direction. The highest catalytic efficiency, 8.61 ± 0.5 s-1 mM-1, was found at pH 9. Additionally, the tentative active site residues, Lys40 and Tyr268, for the alanine racemization reaction were assigned by homology modeling and sequence comparison studies. Using UCSF Chimera, the structure of the EF_Alr homology model was superimposed and compared to the crystal structure of Alr from E. faecalis. KEYWORDS: Alanine Racemase; Enterococcus faecium; Vancomycin-Resistant Enterococci; Homology Modeling; pH Optimum; Kinetic Characterization; SWISS-MODEL Server; Steady-State Kinetics

Is Play Sexually Dimorphic in the Polygamous Squirrel Monkey?

Play behavior is widespread in juvenile mammals and may be a mechanism for practicing skills needed in adulthood. In mammals characterized by strong adult male competition over females, juvenile males perform more social play than do females, and such play may assist in later mating competition. This study examined whether social play behavior is sexually dimorphic in a polygamous neotropical primate, the squirrel monkey (Saimiri collinsi), through a six-week field study of two groups of wild monkeys in Eastern Amazonia, Brazil. We hypothesized that males would conduct more rough-and-tumble play than females and that any sex-based play differences would be more evident in older juveniles. We video recorded juvenile play bouts and scored: age category (younger or older juvenile) and sex of players (male or female); and rough-and-tumble play behaviors (i.e., bite, grab, and wrestle). Juvenile males initiated more play bouts than did females. Most players were older juvenile males, while older juvenile females were the least represented. Older juvenile play bouts occurred mostly among males, while younger juvenile bouts consisted of a more even sex distribution. While younger juveniles did not significantly affect the number of rough-and-tumble behaviors in bouts, the number of behaviors was significantly affected by the sex of older individuals. These results indicate that social play is sexually dimorphic in juvenile S. collinsi; specifically, males play more than females and sex differences are more pronounced in older cohorts. KEYWORDS: Squirrel Monkeys; Mating System; Sexual Dimorphism; Juvenile Period; Development; Play Behavior; Social Behavior; Ethology

Treatment Outcomes in a Partial Hospital Program for Patients with Social Anxiety Disorder: The Effects of Comorbid Major Depression

Although previous studies have examined the impact of comorbid major depressive disorder (MDD) on social anxiety disorder (SAD), the results have been somewhat mixed. Furthermore, most studies have been conducted in inpatient or outpatient settings. Given the large body of literature that suggests that this particular comorbidity can have negative effects on treatment efficacy and outcomes, it is important to continue to explore its impact. The present study aims to clarify contradictions in the literature and expands on previous studies by examining patients in a partial hospitalization setting. Patients at Rhode Island Hospital with a diagnosis of SAD were compared to those with comorbid SAD and MDD on pre-treatment and post-treatment measures of anxiety and depression. The results indicated that while the comorbid group showed significantly less improvement post-treatment on anxiety symptoms and constructs related to remission from depression, they did not show significantly less improvement on depression symptoms. The implications of these results for clinical practice are discussed. KEYWORDS: Social Anxiety Disorder; Major Depressive Disorder; Comorbid Anxiety Disorders; Comorbid Mood Disorders; Treatment Outcomes; Partial Hospitalization Program