Biological and aerodynamic problems with the flight of animals

Biological and aerodynamic considerations related to birds and insects are discussed. A wide field is open for comparative biological, physiological, and aerodynamic investigations. Considerable mathematics related to the flight of animals is presented, including 20 equations. The 15 figures included depict the design of bird and insect wings, diagrams of propulsion efficiency, thrust, lift, and angles of attack and photographs of flapping wing free flying wing only models which were built and flown

Parenting and Motocross: The Whoops and Downs

Many studies address the influences of parenting and contextual factors on child development (Belsky, 1984). Although long-term contextual factors such as poverty and abuse have been shown to be associated with both parent and child behaviors (La Placa & Corlyon, 2016; Salzinger et al, 2002), little research exists on the degree to which short-term situational contexts may affect child behavior. The goal of this study is to identify the influence of parenting behavior on child response after a competitive motocross race. Survey data was collected from 33 parents at several child/adolescent competitions held at a motocross track. First, results indicated that hostility exhibited by the trackside parent, or the parent that spends the most time with their child trackside, at a motocross race was positively related to their child crying after a competition. Additionally, achievement orientation and family cohesion were both positively related to having a child celebrate after the race. Results also show that some situational factors have an influence on child behavior over and above the influence of the family environment factors. Specifically, trackside parent hostility significantly predicts crying after a race. This work informs the literature on the degree to which short-term situational contexts may affect child behavior, as well as provides insight into parent-child relationships within the context of motocross

A Bose-Einstein Approach to the Random Partitioning of an Integer

Consider N equally-spaced points on a circle of circumference N. Choose at random n points out of $N$ on this circle and append clockwise an arc of integral length k to each such point. The resulting random set is made of a random number of connected components. Questions such as the evaluation of the probability of random covering and parking configurations, number and length of the gaps are addressed. They are the discrete versions of similar problems raised in the continuum. For each value of k, asymptotic results are presented when n,N both go to infinity according to two different regimes. This model may equivalently be viewed as a random partitioning problem of N items into n recipients. A grand-canonical balls in boxes approach is also supplied, giving some insight into the multiplicities of the box filling amounts or spacings. The latter model is a k-nearest neighbor random graph with N vertices and kn edges. We shall also briefly consider the covering problem in the context of a random graph model with N vertices and n (out-degree 1) edges whose endpoints are no more bound to be neighbors

De Sitter Space and Spatial Topology

Morrow-Jones and Witt have shown that generic spatial topologies admit initial data that evolve to locally de Sitter spacetimes under Einstein's equations. We simplify their arguments, make them a little more general, and solve for the global time evolution of the wormhole initial data considered by them. Finally we give explicit examples of locally de Sitter domains of development whose universal covers cannot be embedded in de Sitter space.Comment: 21 pages, 7 figure

Parenting and Motocross: The Whoops and Downs

Parenting is a key contributor to socialization (Collins, Maccoby, Steinberg, Hetherington, & Bornstein, 2000). Many studies address the influences of parenting and contextual factors on child development (Belsky, 1984). Although long-term contextual factors have been shown to be associated with parenting behaviors (La Placa & Corlyon, 2016), little research exists on the degree to which short-term situational contexts may affect parenting. This study addressed two research questions 1) to identify both predictors and results of changes in parenting behaviors during the high investment sport of motocross bike racing and 2) to understand what effect the activity has on family dynamics. Survey data was collected from 33 parents at several child/adolescent competitions held at a Pronational Motocross track in Minnesota. A series of regression analyses were conducted followed by a path analysis. First, results indicated that levels of family cohesion, conflict, and achievement orientation affected parenting behavior before and after the race. Cohesion was positively related to increases in warmth expressed by the coaching parent, or the parent who spends the most time with the child trackside. Conflict was found to negatively predict expressed warmth by the coaching parent. Second, the results indicated that change in parenting behavior before and after a race was also associated with child behavior after the race