Projects for 2008-09

Curriculum-Based Measurement Longitudinal Research with Elementary School English Language Learners

Description: It is frequently difficult to assess English Language Learners’ ongoing progress in the general education curriculum and their acquisition of English language proficiency. While St. Paul utilizes annual state tests (i.e., Test of Emerging Academic English) to assess student English language proficiency, a program of formative assessment is also important to ensure that instruction can be designed to address student needs. It is vital that the assessments teachers give to their students are valid and reliable. A program of such assessment, curriculum-based measurement (CBM) is currently utilized in St. Paul mainly for screening purposes, but special education teachers have been using CBM to adjust instruction to meet the needs of their students. Could ELL teachers similarly utilize CBM to adjust instruction and monitor ELL student progress in school? The first research question for this study is: What is the validity and reliability of curriculum-based writing measures in writing as indicators of general writing performance for elementary-school English language learners? A secondary question is: Can CBM measures be used to progress monitor the English writing development for ELL students? Based on preliminary results from last year, it seems that CBM measures could be used to monitor progress in writing, but the question remains: How should teachers utilize the information gleaned from weekly progress monitoring; how can that inform writing instruction? Nearly weekly data on two different writing CBM prompts were collected on area school children to investigate whether type of prompt or scoring procedure or time allocated to the writing produces a more reliable and valid indicator of writing skill. Interest centers on the average slope of growth across the measures and whether the slope varies based on scores of more “acceptable” measures of writing ability (“standardized” assessments).

Faculty: Heather Campbell, Education

Helpful Background: Stat 316 Multileveling Modeling

Comparing two scaly pearl oyster populations: Are differences in life history strategies evolutionary or physiological responses to environmental stress?

Description: Life history demographics are mathematically complex, and challenging to model. In our study organism Pinctada longisquamosa, the scaly pearl oyster juveniles begin life in a planktonic form and only 0.1 mm in diameter. Within the first month of life they metamorphose into sessile bivalves, attached to the substrate with tough fibers called byssal threads. Sometime during their first year of growth, they achieve a critical mass, and differentiate sexually. Typically, all juvenile Pinctada differentiate as males. During their second year of growth (again approx-imately), these oysters achieve a second critical mass, and half re-differentiate into females. Theory tells us that this strategy allows even very small oysters to begin competing for sexual reproduction in that sperm are metabolically inexpensive and can be produced low-cost, by even very tiny individuals, whereas eggs are relatively costly to produce given their substantial stores of yolk and other macromolecules. Hence, a strategy of protandrous hermaphroditism (male-first followed by sex-change), makes physiological and adaptive sense. Curiously, we have come upon two populations of Pinctada that exhibit different life-history-trajectories. In a protected population, we see the classic protandrous life history. In a neighboring population that is uniquely exposed to repetitive annihilation by hurricane activity, the oysters have abandoned protandry for a dioecious life history (they differentiate both male female individuals immediately upon maturation). This may represent an evolutionary shift in strategy driven by annihilation of the adult (female-biased) population coupled with hurricane driven spawning events. As juveniles settle and mature following a storm, there are few females to breed with (adults having been largely exterminated). Hence, any mutation that favors precocious feminization would be favored in a male-biased population.

To properly model and test this hypothesis (the “hurricane hypothesis”), we should like to pursue quantitative approaches to both ecological and evolutionary parameters. Some possible approaches:

Ecology
1) establish growth curves, modeling if possible, the oyster’s growth dynamics. This will allow us to assign ages to oysters of given dimensions, and more accurately assess the timing of maturation and sex-change, and assess the age at which egg formation can be sustained.

2) evaluate the quality and quantity of food in their natural habitats using fluorimetry, and oxygen consumption of organisms in the water column,

3) quantify feeding rates by following the rate at which algae are cleared from a given volume of water,

4) assess the possibility that environmental estrogens may be playing a larger role than the hurricane phenomena in altering sexual differentiation within the different ponds.

Evolution

1) estimate population sizes (the effective breeding population) for each pond,

2) mathematically model the tipping point at which alleles favoring protandry should be balanced against alleles favoring dioecy, and assess the predictions against real measurements in terms of frequency of gender assignment at maturation.

3) do allele assessment to determine the amount of genetic diversity both within the populations and between populations.

Faculty: Eric Cole, Biology

Natal homing as a factor in sex ratios in freshwater turtle populations

Description: In many animals, sex is determined by the temperature of the nest during incubation, a phenomenon known as environmental sex determination (ESD). Studying the factors affecting maternal nest-site choice under ESD can be critically important in understanding both the evolutionary dynamics of the population sex ratio and the conservation implications of human-induced changes in the environment. Previous field work has revealed that turtles may “transmit” their nest-site location across generations through natal homing, whereby females return to nest at the site from which they were hatched. If ESD species exhibit natal homing, it may cause entire families to inherit similar nesting locations and thus similar offspring sex ratios. This interaction is predicted to impact population sex ratios and the evolutionary dynamics of these species.

This study seeks to examine the role of natal homing on the sex ratios of local populations of freshwater turtles. If females are homing to their natal sites, there is an empirical expectation of high genetic relatedness among females nesting in close geographic proximity. Furthermore, because of the influence of local thermal environment on sex ratios, females nesting in close proximity may have positively correlated nest sex ratios. In an ongoing field study, students are using three sets of tools to collect data from nesting snapping turtles in Southern Minnesota; data loggers to track thermal variation throughout incubation, GPS to record nest location, and genetic analysis to determine relatedness among females. These data sets will allow us to construct distance matrices of temperature, geographic location, and genetic distance for the nests throughout our population. While the Mantel test is traditionally used for testing for correlations among two distance matrices, this study presents the interesting mathematical challenge of testing for correlations among three such matrices. While designing an appropriate method to study these relationships may present some interesting challenges, such an analysis will be a crucial first step in addressing these important questions.

Faculty: Steve Freedberg, Biology

Good Computing: life stories of moral exemplars in the computing profession

Description: Explicit attention to computer ethics began with Norbert Weiner’s (1950) groundbreaking book, The Human Use of Human Beings, and the teaching of computer ethics arguably started in the 1970s with the distribution of Walter Maner’s Starter Kit in Computer Ethics (see Bynum, 2001 for a short history). Since that time, many excellent scholars have entered the field and much work has been done. Work on the philosophical groundwork for computing ethics (Tavani, 2002; Floridi, 2008), the policy difficulties associated with computing (Moor, 1997; Nissenbaum, 1998; Tavani & Moor, 2001), and professional ethics in computing (Gotterbarn, 2001; Friedman, 1997) has multiplied and borne much fruit.

Yet oddly, we still know very little about how computer professionals manage to be ethical in their everyday lives. What skills and strategies do they use to navigate the normal (and the unusual) stresses, the conflicting demands, and the multiple possibilities and difficulties of their careers? In psychological terms we are interested in understanding how individuals achieve continued successful performance of ethical behavior in the field of computing. In philosophical terms we might cast the question as how individuals attain and practice the virtues of the computing profession. Certainly if we could learn something about this, it might influence the way we teach computer ethics to those who will become computer professionals.

One way to begin this inquiry is to follow the life stories of computer scientists who are known for their ethical commitment. We have documented 24 of these life stories in a series of interviews with moral exemplars in computing in the United Kingdom and Scandinavia, people who are successfully integrating ethical concern into their practice of computing (Huff & Rogerson, 2005). This is exploratory work, but still it gives us a multifaceted picture of how moral exemplars in computing structure their lives, make their choices, and implement their plans.

Faculty: Chuck Huff, Psychology

Statistics as a tool to further Tuberculosis Genome Research

Description: TB latently infects 1/3 of humanity, killing millions annually, especially in combination with HIV. The sequence of TB genome offers us the best opportunity in decades to understand and combat this ancient disease. St. Olaf currently runs the largest database in the world showing how TB uses its genes in real time to respond to its environment. This database is a fertile field for statistical discovery and analysis. I’d be delighted to speak with any statistics concentrators who might be interested in learning more about the types of projects available.

Faculty: Rob Rutherford, Biology

Helpful background: Statistics 212, interests in biology and/or computer science would all be helpful, but are not required.

World Health Organization

Description: –

Faculty: James Scott, Statistics

Impacts of Electronic Communication Technology on Human Interaction

Description: Each year, students in SOAN 371 (Foundations of Social Science Research) conduct a random-sample survey of St. Olaf students on a topic of general interest, analyze the data, and present their results in various forums. Recents years’ topics have included student satisfaction, use of electronic communication, and close relationships. This year, we will again analyze survey data from St. Olaf College students. Topic options include health (physical health, mental health, substance use, etc.), values (social/political values and their impact on students’ lives), and the transition to adulthood (under current economic/social conditions).

Faculty: Ryan Sheppard, Sociology