Statistical Analysis of Student Performance in Mathematics Courses

We examined the effect of taking AP Calculus in high school on final letter grades in Calculus I, II, and III at Valparaiso University. The data used in our study was obtained from the registrar and included demographic information, entrance exam scores (ACT, SAT, AP, etc.), Valpo GPA for each semester, and final letter grades in all math courses from Spring 2008-Summer 2012. We performed multiple statistical analyses, such as chi-square tests, two-sample t-tests, and multiple regressions, using the statistical software package R. Our results show that students who took AP Calculus in high school on average received higher final letter grades in Calculus I at Valpo, even after controlling for differences in ACT/SAT math scores. In Calculus II and Calculus III at Valpo, students who passed out of the previous calculus course due to AP credit on average performed better or at least approximately the same as students who took the previous calculus course at Valpo, again after controlling for other confounding factors. About the Authors: Katie, Hannah, and Nicolle are Mathematics and Education double majors, as well as part of the VU MSEED program. They are rising sophomores and are interested in pursuing careers as high school mathematics teachers. By analyzing the factors that influence student performance in college mathematics courses, they will be better able to prepare their future students for success in college

The Visual Story of Ruby Red Slippers: Costume Design in Children\u27s Theatre

Clothing communities. Even our shoes are continually sending messages. Ruby red slippers conjure visions of Emerald City, Munchkins, and flying monkeys. Blue suede shoes bring to mind Elvis’s rebellious rock and roll, and Cinderella’s glass slipper is instantly equated with classic, fairy tale romance. Countless studies demonstrate that our clothing sends messages to those around us. As we look throughout history of the last 2500 years, we find that theatre is invariably used for the same purpose: to communicate with or send a message to an audience. It comes as no surprise that theatre has employed costume as a medium though which to achieve this objective. Costumes have coexisted with theatre from its very beginnings. My interest lay in the costume of children’s theatre in the United States and Canada. By examining the role of children’s theatre has historically fulfilled within the society of the United States and Canada and thus its goals today, as well as the role of experience in perception, and the basic aesthetic elements of design, I hope to establish an overview of costume design considerations in the children’s theatre. With the belief that costume is a form of visual communication, this paper’s main objective will be a discussion of effective visual communication through costume design for children between the ages of 4 and 11. In order to best create the framework from which to examine this topic, the following introductory overview will discuss the basic role of costume in theatrical production so as to conclude with statements concerning the relevancy of costume in children’s theatre

On sex-ratio and sibling competition : an insight into reproductive decisions in the black-legged kittiwake (Rissa tridactyla)

Au cours d'un évènement de reproduction, les parents font face à plusieurs décisions qui peuvent influencer leur aptitude. Dans cette thèse, je me suis intéressé à la sexe-ratio et à la compétition dans la fratrie chez la mouette tridactyle (Rissa tridactyla). Tout d'abord, j'ai montré que les parents en moins bonne condition ont produit plus de filles que les autres, ce qui semblait dû à leur coût énergétique plus faible et peut-être aussi à leur plus grand retour en investissement en termes de valeur sélective pour les parents comparativement aux fils. Ensuite, mes résultats ont suggéré que l'asynchronie d'éclosion naturelle était celle qui minimisait les coûts pour les parents et pour les poussins cadets, alors que les poussins aînés semblaient être stressés par leur position dominante. Enfin, les mères ont favorisé la compétitivité de leur poussin cadet seulement lorsqu'elles étaient en conflit avec leur poussin aîné à propos de la réduction de taille de nichée. Cette thèse a donc mis en évidence certains moyens par lesquels les parents peuvent maximiser les bénéfices ou réduire les coûts associés à leur reproduction.During a breeding event, parents face several decisions that may impact their fitness. In this thesis, I have been interested in sex-ratio and sibling competition patterns in the black-legged kittiwake (Rissa tridactyla). First, I showed that parents in poorer condition overproduced daughters, which seems to be due to their lower reproductive cost and, possibly, to their higher fitness return for parents as compared to sons. Then, my results suggested that the natural magnitude of hatching asynchrony minimised the costs for parents and younger siblings, while older siblings seemed to be stressed by their dominant position. Finally, mothers favoured their younger chick's competitiveness only when in conflict over brood reduction with their older chick. This thesis thus highlighted some means through which parents could maximise benefits or reduce costs associated with their reproduction

Investigating Prerequisite Grade Requirements in the Calculus Sequence

The Valparaiso University Mathematics and Computer Science Department has been debating a shift from a D- to a C- in the calculus sequence prerequisite grade requirement. We first researched policies at other colleges and universities. Next, we gathered data on students\u27 self-predicted grades by distributing pre- and post-semester surveys and measuring the accuracy of the results in comparison to the actual grade data. Using the surveys, we also associated students\u27 expectations with their majors. In the end, we investigated whether or not prerequisite grades can predict subsequent course performance. Statistical analysis of the past four years of math student data determined that a student who received a C or lower in the prerequisite class generally would not improve in the subsequent course

Carry-over effects of food supplementation on recruitment and breeding performance of long-lived seabirds

Supplementation of food to wild animals is extensively applied as a conservation tool to increase local production of young. However, in long-lived migratory animals, the carry-over effects of food supplementation early in life on the subsequent recruitment of individuals into natal populations and their lifetime reproductive success are largely unknown. We examine how experimental food supplementation early in life affects: (i) recruitment as breeders of kittiwakes Rissa tridactyla born in a colony on Middleton Island (Alaska) between 1996 and 2006 (n = 1629) that bred in the same colony through 2013 (n = 235); and (ii) breeding success of individuals that have completed their life cycle at the colony (n = 56). Birds were raised in nests that were either supplemented with food (Fed) or unsupplemented (Unfed). Fledging success was higher in Fed compared with Unfed nests. After accounting for hatching rank, growth and oceanic conditions at fledging, Fed fledglings had a lower probability of recruiting as breeders in the Middleton colony than Unfed birds. The per-nest contribution of breeders was still significantly higher for Fed nests because of their higher productivity. Lifetime reproductive success of a subset of kittiwakes that thus far had completed their life cycle was not affected by the food supplementation during development. Our results cast light on the carry-over effects of early food conditions on the vital rates of long-lived animals and support food supplementation as an effective conservation strategy for long-lived seabirds

Understanding Nanopore Window Distortions in the Reversible Molecular Valve Zeolite RHO

Molecular valves are becoming popular for potential biomedical applications. However, little is known concerning their performance in energy and environmental areas. Zeolite RHO shows unique pore deformations upon changes in hydration, cation siting, cation type, or temperature-pressure conditions. By varying the level of distortion of double eight-rings, it is possible to control the adsorption properties, which confer a molecular valve behavior to this material. We have employed interatomic potentials-based simulations to obtain a detailed atomistic view of the structural distortion mechanisms of zeolite RHO, in contrast with the averaged and space group restricted information provided by diffraction studies. We have modeled four aluminosilicate structures, containing Li$^+$, Na$^+$, K$^+$, Ca$^{2+}$, and Sr$^{2+}$ cations. The distortions of the three different zeolite rings are coupled, and the six- and eight-membered rings are largely flexible. A large dependence on the polarizing power of the extra-framework cations and with the loading of water has been found for the minimum aperture of the eight-membered rings that control the nanovalve effect. The calculated energy barriers for moving the cations across the eight-membered rings are very high, which explains the experimentally observed slow kinetics of the phase transition as well as the appearance of metastable phases

Smart bactericides, design, synthesis and characterization.

Preventing microbial resistance to antibiotics is one of the most important challenges of our times, because multiresistant microorganisms are increasingly being reported. An approach based on silver nanoparticles is promising, given that this type of particles has been proven to exhibit antimicrobial activity. In addition, green strategies would be desirable, in which harmful chemicals are replaced by natural products to generate nanoparticles. Specifically, tannic acid (a phenolic metabolite present in many plants) has been used in addition to silver, and Coppo E et al. (2014) report their antimicrobial effects against various types of bacteria, including Escherichia coli (bacteria used in the model). Several synthesis methods have been previously described in combination with characterization by Raman spectroscopy (Dadosh 2009; Cao et al. 2014). However, we have found out that it is essential that the tannic acid solution used in the synthesis is neutralized before adding it to the silver solution to obtain the desired nanoparticles in a green synthesis. We have characterized our nanoparticles by UV-Vis spectrophotometry, and measured their hydrodynamic size and electrostatic stability by dynamic light scattering, which revealed an average size of 10-12 nm and a Zeta potential below -30mV. We have measured the antimicrobial activity using the minimum inhibitory concentration method, which, according to our preliminary results, indicate that said nanoparticles have a high antibacterial power against E.coli Dh5-α at low concentrations of the order of (15-20) μg of nanoparticles/ml. Our goals are to further adjust the range of concentrations and determine what would be the optimum concentration to ensure permanent antibacterial activity. With all the aforementioned, it can be stated that this type of nanoparticles is a very interesting proposal for the challenge of microbial resistance to antibiotics

Combination of XANES spectroscopy and molecular dynamics to probe the local structure in disordered systems

Individual configurations obtained from molecular dynamics have been combined with the computation of x-ray absorption near-edge structure (XANES) spectra to obtain a theoretical estimation of the spectrum corresponding to a system in a condensed medium lacking long-range order. The influence of the different geometries on the spectrum is studied. The results obtained indicate that the reproduction of the features of the XANES spectrum requires a good sampling of geometrical arrangements. As a test case, an aqueous solution of Cr(H2O)6 3+ was selected, since its simulation reproduces well structural results. The contribution of the second hydration shell on the shape of the spectrum was determined.Dirección General de Investigación Científica y Técnica IFD97-118

Ab initio x-ray absorption study of copper K -edge XANES spectra in Cu(II) compounds

This work reports a theoretical study of the x-ray absorption near-edge structure spectra at the Cu K edge in several Cu(II) complexes with N -coordinating ligands showing a square-planar arrangement around metal cation. It is shown that single-channel multiple-scattering calculations are not able to reproduce the experimental spectra. The comparison between experimental data and ab initio computations indicates the need of including the contribution of two electronic configurations (3 d9 and 3 d10 L) to account for a proper description of the final state during the photoabsorption process. The best agreement between theory and experiment is obtained by considering a relative weight of 68% and 32% for the two absorption channels 3 d10 L and 3 d9, respectivelyComisión Interministerial de Ciencia y Tecnología MAT2002-04178-C04-03, BQU2002-02217 y BQU2002- 04364-C02-0