Spatial Reasoning as Related to Solving Story Type Problems

In this study it was hypothesized that the ability to mentally solve II story type problems, those presented in the form of sentences, is significantly related to one\u27s spatial reasoning ability and that a weakness in this ability, when tested by the story type problems, could be compensated for by training in and utilization of overt paper and pencil manipulations. To test the hypothesis, three measures were used. These were the DAT Verbal Reasoning test--used to control the factor of verbal reasoning, the DAT Space Relations test--used to measure spatial reasoning ability, and two forms of a test composed of story type problems--used to measure problem-solving ability. A large group of college students (146) were first tested on the DAT tests and then 18 pairs were selected which were matched as nearly as possible on verbal reasoning abilities while keeping their spatial reasoning abilities as diverse as possible. The 18 pairs were then tested and retested on the problem-solving tests with half of the pairs receiving problem-solving instructions prior to the retest. Statistical analysis of the results confirmed the hypothesis in that it revealed a substantial positive correlation between spatial reasoning ability and the ability to solve story type problems. Also, an analysis of the results showed, to a significant degree, that a weakness in spatial reasoning ability, when used to solve the type of problems considered, can be compensated for by using paper and pencil manipulations involving graphic procedures

Three Essays on Experimental and Microeconomics

This dissertation contains three chapters on experimental economics and microeconomics. In the first chapter, Dynamic Investment and Preferences over the Resolution of Risk, I report the results of a laboratory experiment which attempts to explain the finding that individuals invest less in risky assets when risk is gradually resolved over time, rather than all at once. Though the literature has traditionally attributed this behavior to a cognitive error, Koszegi and Rabin (2009) recently characterized this finding as the result of non-standard preferences over the resolution of risk. My results reject the traditional "cognitive errors" explanation in favor of Koszegi and Rabin's "non-standard preferences" explanation. In the second chapter, Kidney Co-operative: A Mechanism to Improve on Human Kidney Markets, myself and coauthors propose a mechanism called the kidney co-operative which is designed to provide sufficient incentives to alleviate the human kidney shortage, while at the same time addressing the concerns regarding the potential losers to such a reform. We show that it is reasonable to expect that the number of transplants will be larger under the kidney co-operative mechanism than under either the status quo or the conventional market mechanism. In the third chapter, Charity in the Laboratory:Matching, Competition, and Group Identity, myself and a coauthor study the effects of donation matching, competition, and group membership on charitable donations using a laboratory experiment. We find that providing matching donations to all subjects orhaving individuals compete for the privilege to have their donations matched (we match the top half of donations in each session), raises donation levels modestly. However, arbitrarily assigning subjects to teams which competed for matching funds substantially raised donation levels. We appeal to the notions of group identity and team dynamics to explain our results

Rotary Drum Separator and Pump for the Sabatier Carbon Dioxide Reduction System

A trade study conducted in 2001 selected a rotary disk separator as the best candidate to meet the requirements for an International Space Station (ISS) Carbon Dioxide Reduction Assembly (CRA). The selected technology must provide micro-gravity gasfliquid separation and pump the liquid from 10 psia at the gasfliquid interface to 18 psia at the wastewater bus storage tank. The rotary disk concept, which has pedigree in other systems currently being built for installation on the ISS, failed to achieve the required pumping head within the allotted power. The separator discussed in this paper is a new design that was tested to determine compliance with performance requirements in the CRA. The drum separator and pump @SP) design is similar to the Oxygen Generator Assembly (OGA) Rotary Separator Accumulator (RSA) in that it has a rotating assembly inside a stationary housing driven by a integral internal motor. The innovation of the DSP is the drum shaped rotating assembly that acts as the accumulator and also pumps the liquid at much less power than its predecessors. In the CRA application, the separator will rotate at slow speed while accumulating water. Once full, the separator will increase speed to generate sufficient head to pump the water to the wastewater bus. A proof-of- concept (POC) separator has been designed, fabricated and tested to assess the separation efficiency and pumping head of the design. This proof-of-concept item was flown aboard the KC135 to evaluate the effectiveness of the separator in a microgravity environment. This separator design has exceeded all of the performance requirements. The next step in the separator development is to integrate it into the Sabatier Carbon Dioxide Reduction System. This will be done with the Sabatier Engineering Development Unit at the Johnson Space Center

Predictions of the causal entropic principle for environmental conditions of the universe

The causal entropic principle has been proposed as a superior alternative to the anthropic principle for understanding the magnitude of the cosmological constant. In this approach, the probability to create observers is assumed to be proportional to the entropy production \Delta S in a maximal causally connected region -- the causal diamond. We improve on the original treatment by better quantifying the entropy production due to stars, using an analytic model for the star formation history which accurately accounts for changes in cosmological parameters. We calculate the dependence of \Delta S on the density contrast Q=\delta\rho/\rho, and find that our universe is much closer to the most probable value of Q than in the usual anthropic approach and that probabilities are relatively weakly dependent on this amplitude. In addition, we make first estimates of the dependence of \Delta S on the baryon fraction and overall matter abundance. Finally, we also explore the possibility that decays of dark matter, suggested by various observed gamma ray excesses, might produce a comparable amount of entropy to stars.Comment: RevTeX4, 13pp, 10 figures; v2. clarified introduction, added ref