5,310 research outputs found

    SCU Courses

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    Registering for classes is a nightmare that students at Santa Clara University undergo three or more times a year while juggling midterm exams. It’s hard to find a schedule that works well for you, balancing the need to take classes that will satisfy degree progress with the need to work around obligations outside of class and avoid getting stuck in an 8am lecture. SCU Courses is a web app where students input their current degree progress and receive a list of possible schedules to take next quarter, collapsing the time-consuming process of carefully crafting a schedule into just one step: choose your favorite

    Wage Posting Without Full Commitment

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    Wage posting models of job search typically assume that firms can commit to paying workers the posted wage. This paper investigates the consequences of relaxing this assumption. Under ``downward'' commitment, firms can commit only to paying at least their advertised wage. We show that wage posting is always an equilibrium, although in special cases other equilibria can exist. Surprisingly, the wage posting equilibrium in our economy is identical to the equilibrium when firms can commit to paying exactly their posted wage. When firms cannot even commit to paying at least their advertised wage, equilibrium exhibits job auctions with wage dispersion which generally is not constrained efficient.

    β-arrestin regulates estradiol membrane-initiated signaling in hypothalamic neurons.

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    Estradiol (E2) action in the nervous system is the result of both direct nuclear and membrane-initiated signaling (EMS). E2 regulates membrane estrogen receptor-α (ERα) levels through opposing mechanisms of EMS-mediated trafficking and internalization. While ß-arrestin-mediated mERα internalization has been described in the cortex, a role of ß-arrestin in EMS, which underlies multiple physiological processes, remains undefined. In the arcuate nucleus of the hypothalamus (ARH), membrane-initiated E2 signaling modulates lordosis behavior, a measure of female sexually receptivity. To better understand EMS and regulation of ERα membrane levels, we examined the role of ß-arrestin, a molecule associated with internalization following agonist stimulation. In the present study, we used an immortalized neuronal cell line derived from embryonic hypothalamic neurons, the N-38 line, to examine whether ß-arrestins mediate internalization of mERα. β-arrestin-1 (Arrb1) was found in the ARH and in N-38 neurons. In vitro, E2 increased trafficking and internalization of full-length ERα and ERαΔ4, an alternatively spliced isoform of ERα, which predominates in the membrane. Treatment with E2 also increased phosphorylation of extracellular-signal regulated kinases 1/2 (ERK1/2) in N-38 neurons. Arrb1 siRNA knockdown prevented E2-induced ERαΔ4 internalization and ERK1/2 phosphorylation. In vivo, microinfusions of Arrb1 antisense oligodeoxynucleotides (ODN) into female rat ARH knocked down Arrb1 and prevented estradiol benzoate-induced lordosis behavior compared with nonsense scrambled ODN (lordosis quotient: 3 ± 2.1 vs. 85.0 ± 6.0; p < 0.0001). These results indicate a role for Arrb1 in both EMS and internalization of mERα, which are required for the E2-induction of female sexual receptivity

    Ergodic Capacity Analysis of Amplify-and-Forward MIMO Dual-Hop Systems

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    This paper presents an analytical characterization of the ergodic capacity of amplify-and-forward (AF) MIMO dual-hop relay channels, assuming that the channel state information is available at the destination terminal only. In contrast to prior results, our expressions apply for arbitrary numbers of antennas and arbitrary relay configurations. We derive an expression for the exact ergodic capacity, simplified closed-form expressions for the high SNR regime, and tight closed-form upper and lower bounds. These results are made possible to employing recent tools from finite-dimensional random matrix theory to derive new closed-form expressions for various statistical properties of the equivalent AF MIMO dual-hop relay channel, such as the distribution of an unordered eigenvalue and certain random determinant properties. Based on the analytical capacity expressions, we investigate the impact of the system and channel characteristics, such as the antenna configuration and the relay power gain. We also demonstrate a number of interesting relationships between the dual-hop AF MIMO relay channel and conventional point-to-point MIMO channels in various asymptotic regimes.Comment: 40 pages, 9 figures, Submitted to to IEEE Transactions on Information Theor

    A Minority of Patients with Type 1 Diabetes Routinely Downloads and Retrospectively Reviews Device Data.

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    BackgroundIn type 1 diabetes (T1D), periodic review of blood glucose and insulin dosing should be performed, but it is not known how often patients review these data on their own. We describe the proportion of patients with T1D who routinely downloaded and reviewed their data at home.Materials and methodsA cross-sectional survey of 155 adults and 185 caregivers of children with T1D at a single academic institution was performed. "Routine Downloaders" (downloaded four or more times in the past year) were also considered "Routine Reviewers" if they reviewed their data most of the time they downloaded from devices. Logistic regression was used to identify factors associated with being a Routine Reviewer.ResultsOnly 31% of adults and 56% of caregivers reported ever downloading data from one or more devices, whereas 20% and 40%, respectively, were considered Routine Downloaders. Only 12% of adults and 27% of caregivers were Routine Reviewers. Mean hemoglobin A1c was lower in Routine Reviewers compared with non-Routine Reviewers (7.2±1.0% vs. 8.1±1.6% [P=0.03] in adults and 7.8±1.4% vs. 8.6±1.7% [P=0.001] in children). In adjusted analysis of adults, the odds ratio of being a Routine Reviewer of one or more devices for every 10-year increase in age was 1.5 (95% confidence interval, 1.1, 2.1 [P=0.02]). For every 10 years since diabetes diagnosis, the odds ratio of being a Routine Reviewer was 1.7 (95% confidence interval, 1.2, 2.4 [P=0.01]). For caregivers, there were no statistically significant factors associated with being a Routine Reviewer.ConclusionsA minority of T1D patients routinely downloads and reviews data from their devices on their own. Further research is needed to understand obstacles, provide better education and tools for self-review, and determine if patient self-review is associated with improved glycemic control

    Viscoelastic characterization of collagen-GAG scaffolds

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    Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (p. 43-45).An experimental study was performed to determine whether or not collagen-GAG scaffolds exhibit linear viscoelastic behavior. Tension tests were performed on dry and hydrated engineered collagen-GAG scaffolds in order to develop a stress-strain curve. Strains that fell in the linear elastic region of these curves were selected and then used in stress relaxation tests that were also performed on dry and hydrated specimens. The relaxation modulus was calculated from the resulting stress relaxation curves at different strain levels and compared to each other to determine viscoelastic linearity. In addition to the determination of viscoelastic linearity, a water bath was designed in the hopes of performing stress relaxation tests in hydrated environment with the temperature maintained at 37°C, the temperature of the human body. These tests will aid in the future studies of how cells contract and apply force to the scaffolds since no previous studies have looked at the time dependent mechanical properties of these scaffolds. Moreover, the data can be used in the future to determine whether the viscoelastic response contributes to cellular processes such as migration speeds, attachment, and contraction.by Matthew Q. Wong.S.B

    Design, Evaluation, and Particle Size Characterization of an In-Duct Flat Media Particle Loading Test System for Nuclear-Grade Asme Ag-1 Hepa Filters

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    The design and performance evaluation of in-duct, isokinetic samplers capable of testing flat sheet, nuclear-grade High Efficiency Particulate Air (HEPA) filters simultaneously with a radial filter testing system is discussed in this study. Evaluations within this study utilize challenge aerosols of varying particle diameters and masses such as hydrated alumina, Arizona test dust, and flame-generated acetylene soot. Accumulated mass and pressure drop for each in-duct sampler is correlated to the full-scale radial filter accumulated mass from initial to 10 in w. c. of loading. SEM imaging of samples at 25%, 50%, 75% and 100% loading verifies particle sizes with instrumentation used, revealing filter clogging resulting from particle impaction and interception. The U.S Department of Energy requires prototype nuclear-grade HEPA filters to be qualified under ASME AG-1 standards. The data obtained can be used to determine baseline performance characteristics on pleated radial filter medium for increased loading integrity and lifecycle endurance

    Energy Harvesting From Exercise Machines - DC-DC Buck Boost Converter (LT3791)

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    Cal Poly’s ongoing Energy Harvesting From Exercise Machines (EHFEM) project proposes sustainability and energy saving costs through modifying exercise machines generating DC power, providing a renewable energy resource through physical exercise. The EHFEM project contains multiple sub-projects involving modifying several different exercise machines. Each machine generates DC power and an inverter converts this power to AC. This AC power returns to the grid. This project addresses an issue involving a previously installed DC-DC converter not returning power properly. When generating DC power, the grid demands a specific AC voltage, but the generated power through the previous DC-DC converter and power inverter encountered several problems. One previous converter outputted the desired DC output, but at the cost of low efficiency
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