Three-axis magnetometer calibration with norm preservation

This thesis proposes a set of methods for the purpose of improving the calibration of three-axis magnetometers. Specifically, these methods aim to improve the accuracy of the bias estimation methods currently in use. The first proposed method utilizes a constrained optimization problem based on norm preserving. The second proposed method finds the same bias estimate as the first method, but in a computationally more efficient manner. The last proposed method tackles the case where the value of the local geomagnetic field is only imprecisely known. Computer simulations demonstrate the viability of the proposed methods

An applied paleoecology case study: Bahia Grande, Texas prior to construction of the Brownsville Ship Channel

Bahia Grande is a large lagoon located within Laguna Atascosa National Wildlife Refuge in Cameron County, Texas. When the Brownsville Ship Channel was built along the southern end of the lagoon in 1936, Bahia Grande was cut off from the marine water of Laguna Madre. Since that time, Bahia Grande has been primarily dry with only ephemeral fresh water coming from heavy rainfall events, resulting in a severe decline in biological productivity. A restoration project led by the U.S. Fish and Wildlife Service has proposed to cut new channels between Bahia Grande and the Ship Channel to restore the connection with Laguna Madre. This is a large-scale project with major implications for the water quality, surrounding ecology, and associated biota in the region. Unfortunately, because very little is known about Bahia Grande prior to isolation, it is difficult to predict whether the results of the restoration will be comparable to the pre-Ship Channel environment. Paleoecological data provide the best opportunity to understand what Bahia Grande was like in the past. This study uses statistical analyses of the molluscan death assemblages from Bahia Grande to gain a better understanding of the environmental conditions in the lagoon before it was isolated. The first question addressed is how does Bahia Grande relate to other water bodies on the Texas coast? This may provide a modern analog to the past conditions in Bahia Grande. The second question inquires whether there are any local patterns or variations within Bahia Grande and several smaller surrounding lagoons. These results provide an important baseline for comparison with the restored lagoon. The results of this investigation show that, in a regional context, Bahia Grande was most similar to Alazan Bay and Baffin Bay, which are mostly enclosed shallow bays with high salinities due to the arid climate and limited freshwater inflow. Within Bahia Grande, there are several distinct molluscan assemblages. Salinity and water coverage are the most likely environmental factors responsible for the differences within Bahia Grande. Additionally, data from surrounding lagoons strongly indicate that some connections with Bahia Grande existed in the past

A Hope Intervention Compared to Friendly Visitors as a Technique to Reduce Depression among Older Nursing Home Residents

Depression is common among older persons. An experimental study was undertaken to test the impact of a four-week hope program on depressed nursing home residents. Residents aged 65 or older, who met the criteria for this pilot study and agreed to participate, were randomly assigned to (a) an intervention group, and provided with weekday hope interventions mainly involving positive messages and pictures or (b) a modified control group, and provided with a friendly weekday greeting. The structured hope intervention was not proven effective for reducing depression or raising hope. Instead, a significant reduction in depression among the control subjects was found, as well as a nonsignificant increase in their level of hope. Although these findings suggest friendly visitors may be a more efficacious nonpharmacological approach for reducing depression, further investigations are needed to confirm this and to explore the impact of other hope interventions

Study of ferritin self-assembly and heteropolymer formation by the use of Fluorescence Resonance Energy Transfer (FRET) technology

The high stability and strong self-assembly properties made ferritins the most used proteins for nanotechnological applications. Human ferritins are made of 24 subunits of the H- and L-type that coassemble in an almost spherical nanocage 12 nm across, delimiting a large cavity. The mechanism and kinetics of ferritin self-assembly and why H/L heteropolymers formation is favored over the homopolymers remain unclarified. In order to study this, we used the Fluorescence Resonance Energy Transfer (FRET) tool by binding multiple donor or acceptor Alexa Fluor fluorophores on the outer surface of human H and L ferritins and then denaturing and reassembling them in different proportions and conditions. The FRET efficiency increase from 0.7 in the assembled allowed to study the assembly kinetics. We found that their assembly was complete in about one hour, and that the initial rate of self-assembly of H/L heteropolymers was slightly faster than that of the H/H homopolymers. Then, by adding various proportions of unlabeled H or L-chains to the FRET system we found that the presence of the L-chains displaced the formation of H-H dimers more efficiently than that of the H-chains. This favored formation of H/L heterodimers, which is the initial step in ferritin self-assembly, contributes to explain the preferred formation of H/L heteropolymers over the H or L homopolymers. Moreover, we found that the H-chains arrange at distant positions on the heteropolymeric shell until they reach a number above eight, when they start to co-localize.This work was partially supported by MIUR grant PRIN10-11 to PA, and by Telethon grant GGP15064 to PA. FC was recipient of a Post-Doc Fellowship from University of Brescia, and was partially supported by CIB (Consorzio Italiano di Biotecnologie)

Numerical Analysis of Penetration Resistance Effects of Metal Matrix Composite Reinforcing in Spaced and Direct Configurations

Towards the pursuit of furthering the understanding of lightweight penetration resistant systems a study regarding metal matrix composite materials in penetration resistant configurations is considered. The metal matrix composite, MMC, studied is Al 6061/SiC and has a density very similar to homogeneous aluminum which is of interest when considering lightweight resistant systems. This effort seeks to by numerical analysis of experimentally validated models determine the effect of MMC inclusion in a system and additionally the effect of different configurations on the performance of the total system. This study focused on common reinforcement applications on aluminum base material targets. While the MMC reinforcement consistently displayed an improvement to the resistance of the system, there was not a significant difference in the resistance of the different configurations.https://scholarsjunction.msstate.edu/fea/1002/thumbnail.jp

Millions of Owners, not Hundreds of Millionaires: An Analysis of the Middle Class as a Requisite Condition for Democracy in Contemporary Russia

Building on Lipset\u27s modernization theory, this thesis makes the argument that a robust, independent middle class is vital for the long term sustenance of liberal democracy in Russia. Following a discussion of scholarly literature on what constitutes democracy and the middle class, a historical analysis compares and contrasts the trajectories of the middle class and democracy in Russia from the late-Soviet Era to the present, This thesis draws on public opinion polling, media reports (both Russian and foreign), and scholarly works to perform a mixed qualitative and quantitative analysis to show that middle class Russians provide the most reliable base of support for democracy and that it has been the weakness of the middle class which has left Russia vulnerable to an illiberal relapse. Moving forward, this suggests that promoting economic growth in the middle class is the best method to encourage democracy in Russia and that any brief forays in to democracy are unlikely to prove sustainable unless they are preceded or accompanied by a corresponding growth of the middle class

Putting information foraging theory to work: Community-based design patterns for programming tools

The design of programming tools is slow and costly. To ease this process, we developed a design pattern catalog aimed at providing guidance for tool designers. This catalog is grounded in Information Foraging Theory (IFT), which empirical studies have shown to be useful for understanding how developers look for information during development tasks. New design patterns, authored by members of the research community for the catalog, concretely explain how to apply IFT in tool design. In our evaluation, qualitative analyses revealed the community-written design patterns compared well in quality to patterns that we had ourselves published in a smaller, peer-reviewed catalog