Perceived value of faculty-developed course websites: A student-faculty comparison

This study is a case-study examination of faculty-developed course websites and their usage within a single mid-western community college environment. Its purpose is to develop an understanding of the perceived value of selected course websites from both student and faculty perspectives based on website design and use. The study analyzes course websites from instructional and technological theoretical perspectives, drawing from literature in the fields of education and technology studies. To understand course websites within the context of their usage, three selected course websites were paired with the instructor and a subset of students to form a case study unit. The case study methodology offered an opportunity for in-depth qualitative data collection through theory-driven examination of website features, observation of website use, and in-depth interviews with students and faculty. Study findings indicate that perceived value is strengthened by the amount and quality of course-specific content while lessened by irrelevant content and/or lack of significant content. Because constructivist strategies embody interactive learning styles, web-enabling interactive content on course websites has the potential to create constructivist learning opportunities. Several factors influence course websites design and perceived value perspectives. Included among these are student involvement in the design process, professional development opportunities that support faculty development of course websites, faculty members technical abilities, and institutional support

Intrabodies Binding the Proline-Rich Domains of Mutant Huntingtin Increase Its Turnover and Reduce Neurotoxicity

Although expanded polyglutamine (polyQ) repeats are inherently toxic, causing at least nine neurodegenerative diseases, the protein context determines which neurons are affected. The polyQ expansion that causes Huntington's disease (HD) is in the first exon (HDx-1) of huntingtin (Htt). However, other parts of the protein, including the 17 N-terminal amino acids and two proline (polyP) repeat domains, regulate the toxicity of mutant Htt. The role of the P-rich domain that is flanked by the polyP domains has not been explored. Using highly specific intracellular antibodies (intrabodies), we tested various epitopes for their roles in HDx-1 toxicity, aggregation, localization, and turnover. Three domains in the P-rich region (PRR) of HDx-1 are defined by intrabodies: MW7 binds the two polyP domains, and Happ1 and Happ3, two new intrabodies, bind the unique, P-rich epitope located between the two polyP epitopes. We find that the PRR-binding intrabodies, as well as VL12.3, which binds the N-terminal 17 aa, decrease the toxicity and aggregation of HDx-1, but they do so by different mechanisms. The PRR-binding intrabodies have no effect on Htt localization, but they cause a significant increase in the turnover rate of mutant Htt, which VL12.3 does not change. In contrast, expression of VL12.3 increases nuclear Htt. We propose that the PRR of mutant Htt regulates its stability, and that compromising this pathogenic epitope by intrabody binding represents a novel therapeutic strategy for treating HD. We also note that intrabody binding represents a powerful tool for determining the function of protein epitopes in living cells

Terramechanics and Machine Learning for the Characterization of Terrain

An instrumented rover wheel can collect vast amounts of data about a planetary surface. Planetary surfaces are changed by complex geological processes which can be better understood with an abundance of surface data and the use of terramechanics. Identifying terrain parameters such as cohesion and angle of friction hold importance for both the rover driver and the planetary scientist. Knowledge of terrain characteristics can warn of unsafe terrain and flag potential interesting scientific sites. The instrumented wheel in this research utilizes a pressure pad to sense load and sinkage, a string potentiometer to measure slip, and records motor current draw. This thesis demonstrates the utilization of the instrumented wheel\u27s data to estimate cohesion, angle of friction and grain size and demonstrates a machine learning solution for classifying terrain types with the same data. Mars simulants available at NASA-JPL were used for the collection of the data. Two machine learning classifiers were explored: Random Forest and Support Vector Machine. Binary and multi-class classification were both demonstrated and it is proposed that the classification model can identify terrain types based on the instrumented wheel data. The Random Forest model performed best in all classification types

Sponges impacts on coral reef nitrogen cycling, Key Largo, Florida

Sponges are potentially important drivers of nitrogen cycling on Caribbean coral reefs due to their capacity to filter large volumes of water, their dense microbial communities, and their large population size. Given the potential role that nitrogen plays in controlling primary production and reef health, it is important to understand and quantify the nitrogen fluxes between sponges, their associated microbial communities, and the surrounding water column. The main goal of this dissertation is to characterize the role of sponges and their microbial assiciates in reef N cycling, specifically: 1) to quantify the flux of dissolved inorganic nitrogen (DIN) to the water column, 2) to investigate the process of nitrification, and 3) to measure nitrogen fixation rates in sponges. Nitrogen fixation rates in sponges were found to be very low relative to the ambient water column; therefore, sponge-hosted nitrogen fixation probably does not contribute significantly to sponge nutrition or to inputs of new nitrogen for the reef. However, sponges were found to be a large source of DIN. The DIN flux from the sponge community was measured using a combination of incubation experiments and a novel in situ method and found to be 660 ± 130 mol m-2 h-1, which is approximately ten times higher than other reported benthic nutrient fluxes. Most of this DIN is released in the form of nitrate due to active communities of ammonia oxidizers and nitrifiers hosted by many of the most abundant sponge species. At present it is unknown whether the ammoniaoxidizing community is dominated by archaea or bacteria, but the results of this study show that the isotopic fractionation and sensitivity to chemical inhibition are consistent with bacterial ammonia oxidizers. Because nitrogen fixation rates were negligible compared to DIN flux rates, spongeiii produced DIN is likely derived from the remineralization of organic matter. Therefore, although sponges do not appear to facilitate fluxes of new nitrogen for the reef, they do appear to regenerate large quantities of inorganic nutrients, and to facilitate the oxidation of ammonium to nitrate

Perturbation with Intrabodies Reveals That Calpain Cleavage Is Required for Degradation of Huntingtin Exon 1

Background: Proteolytic processing of mutant huntingtin (mHtt), the protein that causes Huntington's disease (HD), is critical for mHtt toxicity and disease progression. mHtt contains several caspase and calpain cleavage sites that generate N-terminal fragments that are more toxic than full-length mHtt. Further processing is then required for the degradation of these fragments, which in turn, reduces toxicity. This unknown, secondary degradative process represents a promising therapeutic target for HD. Methodology/Principal Findings: We have used intrabodies, intracellularly expressed antibody fragments, to gain insight into the mechanism of mutant huntingtin exon 1 (mHDx-1) clearance. Happ1, an intrabody recognizing the proline-rich region of mHDx-1, reduces the level of soluble mHDx-1 by increasing clearance. While proteasome and macroautophagy inhibitors reduce turnover of mHDx-1, Happ1 is still able to reduce mHDx-1 under these conditions, indicating Happ1-accelerated mHDx-1 clearance does not rely on these processes. In contrast, a calpain inhibitor or an inhibitor of lysosomal pH block Happ1-mediated acceleration of mHDx-1 clearance. These results suggest that mHDx-1 is cleaved by calpain, likely followed by lysosomal degradation and this process regulates the turnover rate of mHDx-1. Sequence analysis identifies amino acid (AA) 15 as a potential calpain cleavage site. Calpain cleavage of recombinant mHDx-1 in vitro yields fragments of sizes corresponding to this prediction. Moreover, when the site is blocked by binding of another intrabody, V_L12.3, turnover of soluble mHDx-1 in living cells is blocked. Conclusions/Significance: These results indicate that calpain-mediated removal of the 15 N-terminal AAs is required for the degradation of mHDx-1, a finding that may have therapeutic implications

ORFEUS II Far-UV Spectroscopy of AM Herculis

Six high-resolution (\lambda/\Delta\lambda ~ 3000) far-UV (\lambda\lambda = 910-1210 \AA) spectra of the magnetic cataclysmic variable AM Herculis were acquired in 1996 November during the flight of the ORFEUS-SPAS II mission. AM Her was in a high optical state at the time of the observations, and the spectra reveal emission lines of O VI \lambda\lambda 1032, 1038, C III \lambda 977, \lambda 1176, and He II \lambda 1085 superposed on a nearly flat continuum. Continuum flux variations can be described as per Gansicke et al. by a ~ 20 kK white dwarf with a ~ 37 kK hot spot covering a fraction f~0.15 of the surface of the white dwarf, but we caution that the expected Lyman absorption lines are not detected. The O VI emission lines have narrow and broad component structure similar to that of the optical emission lines, with radial velocities consistent with an origin in the irradiated face of the secondary and the accretion funnel, respectively. The density of the narrow- and broad-line regions is n_{nlr} ~ 3\times 10^{10} cm^{-3} and n_{blr} ~ 1\times 10^{12} cm^{-3}, respectively, yet the narrow-line region is optically thick in the O VI line and the broad-line region is optically thin; apparently, the velocity shear in the broad-line region allows the O VI photons to escape, rendering the gas effectively optically thin. Unexplained are the orbital phase variations of the emission-line fluxes.Comment: 15 pages, 6 Postscript figures; LaTeX format, uses aaspp4.sty; table2.tex included separately because it must be printed sideways - see instructions in the file; accepted on April 17, 1998 for publication in The Astrophysical Journa

Biological Implications of Hydroxyapatite Coatings on 3D Printed Titanium Implants

This study sought to determine the growth of and viability of osteoblast cells on hydroxyapatite coatings of 3D-printed titanium implants. The experiment used twenty 3D-printed titanium disks each of which had a determined surface roughness. These disks were printed by Tangible Solutions, LLC (Fairborn, OH) and then sonicated. Ten of the disks were coated with hydroxyapatite through the process of electrodeposition using an open cell and a three lead potentiostat. Using the hydroxyapatite coated titanium disks and uncoated disks, two four-day growth trials were performed. Two trials used five control disks (uncoated titanium disks) and five coated disks each, making an n of 10 for the total experiment. The disks were each placed into the wells of a culture plate and each disk was seeded with 15,000 human osteoblast cells. After four days in the incubator, the cells were removed using trypsin and the counted using the CytoSmart Automated Hemocytometer. The cell count from each disk as well as the viability of the cells from each disk were recorded. Means comparison was performed using Tukey-Kramer method of analysis. Results from the cell count portion of the experiment showed that the mean of the hydroxyapatite group was not significantly greater than the control group (p=0.83). In addition, cell viability of the hydroxyapatite group was also not significantly different than the control group (p=0.31). This data was unexpected but may be due to a change in the surface roughness between the two groups caused by the hydroxyapatite coating decreasing the surface roughness. The surface roughness selected for the experiment was chosen due to it being the most ideal for osteoblast growth, but any less rough surfaces were shown to be less ideal for osteoblast cell growth. Future Experiments will remove the variable of surface roughness

Small scale vegetable oil extraction

The processes required to manufacture human food from oilseeds and nuts vary considerably, depending on the raw materials and the scale of the operation. Large-scale producers can select equipment from a range of manufacturers, but the choice for smaller manufacturers is generally limited. Small-Scale Vegetable Oil Extraction presents the options available for processing a range of common oilseeds from domestic to village scales of operation. Details are provided on the type and source of equipment, and the requirements for financial success are examined. The publication will be of interest both to entrepreneurs and NGOs considering setting up oilseed operations

Development and validation of a spectro-temporal processing test for cochlear-implant listeners.

Psychophysical tests of spectro-temporal resolution may aid the evaluation of methods for improving hearing by cochlear implant (CI) listeners. Here the STRIPES (Spectro-Temporal Ripple for Investigating Processor EffectivenesS) test is described and validated. Like speech, the test requires both spectral and temporal processing to perform well. Listeners discriminate between complexes of sine sweeps which increase or decrease in frequency; difficulty is controlled by changing the stimulus spectro-temporal density. Care was taken to minimize extraneous cues, forcing listeners to perform the task only on the direction of the sweeps. Vocoder simulations with normal hearing listeners showed that the STRIPES test was sensitive to the number of channels and temporal information fidelity. An evaluation with CI listeners compared a standard processing strategy with one having very wide filters, thereby spectrally blurring the stimulus. Psychometric functions were monotonic for both strategies and five of six participants performed better with the standard strategy. An adaptive procedure revealed significant differences, all in favour of the standard strategy, at the individual listener level for six of eight CI listeners. Subsequent measures validated a faster version of the test, and showed that STRIPES could be performed by recently implanted listeners having no experience of psychophysical testing