2,139 research outputs found

    Very Low Power Cockcroft-Walton Voltage Multiplier for RF Energy Harvesting Applications

    Get PDF
    A device was required that could harvest the electromagnetic energy present in ambient radio frequency (RF) signals. A part of this device must convert the AC RF signal received by the antenna into a DC signal that can be used in an embedded application. Since the RF signal amplitude is small, it must first be amplified and rectified to become a usable signal. The Cockcroft-Walton voltage multiplier is a subsystem of the design which ideally converts a 100 mV AC signal coming from the antenna to a 350 mV DC signal. The output of the voltage multiplier is used to power another subsystem. At 10 MHz, the Cockcroft-Walton multiplier was able to output a DC voltage of 350 mV given an AC input signal of 140 mV. The results of the testing show verifiable proof-of-concept that the Cockcroft-Walton voltage multiplier has the potential to be used for low power RF energy harvesting applications

    Drug Policy and the HIV Pandemic in Russia and Ukraine

    Get PDF
    Over the past three years Russia and Ukraine have experienced one of the fastest growing HIV pandemics in Europe. In contrast to other parts of the world, the main driver behind the rate of infection is injecting drug use. Recent government policies have placed a heavy emphasis on reducing availability and on harsh punishments for drug users. This approach has not succeeded in significantly reducing the level of drug use. It has pushed the drug scene underground and increased risky behaviours among vulnerable groups. In the absence of measures to reduce infections and reverse the rate of transmission, the long-term impact of HIV/AIDS on population growth and economic development is likely to be grave

    NJ and PA Once Again: What Happened to Employment When the PA-NJ Minimum Wage Differential Disappeared?

    Get PDF
    Card and Krueger's analysis of the impact of the 1992 increase in the NJ state minimum wage is very well known and still controversial. Interestingly, the original NJ-PA natural experiment was followed by another one involving the same two states, an experiment that has not yet been noted or examined. In 1996 and 1997, the federal minimum wage was increased in two steps, from 4.25to4.25 to 5.15, thereby increasing the minimum wage by 0.90inPAbutbyjust0.90 in PA but by just 0.10 in NJ. We use CPS data from 1995 and 1998 to examine the impacts on employment, using difference-in-difference and difference-in-difference-in-difference estimators that exploit within- state and between-state comparisons. We find consistent evidence that employment of “at-risk” groups was negatively impacted in PA relative to other groups in PA and to comparable groups in NJ.Minimum Wage, Card-Krueger

    Ordering the Reidemeister moves of a classical knot

    Full text link
    We show that any two diagrams of the same knot or link are connected by a sequence of Reidemeister moves which are sorted by type.Comment: This is the version published by Algebraic & Geometric Topology on 18 May 200

    Longitudinal Study of Lanana Creek

    Get PDF
    A longitudinal study was done to collect data on the various conditions of LananaCreek in Nacogdoches, Texas over a seven week span from September 14 to November 2, 2018. The part of the creek studies is a 3.5 mile stretch from East Austin Street to Hoya Soccer Complex, mostly located on the campus of Stephen F. Austin State University. There were 6 different testing sites selected along this expanse. Collection of samples was performed by the General Chemistry I Honors class as part of the laboratory experience. Once collected, the samples were transported back to the lab for testing. The tests performed on the samples included determination of the pH, total solids, total dissolved solids, water hardness, anion concentration, and alkalinity. Each of these tests analyzes for a different parameter that is essential in evaluating the health of the ecosystem as a whole and gives a good reflection of the overall health of the creek’s surrounding environment. The results were compared to EPA standards. During the testing period, there were significant rain events generating variable results after each sampling, but the overall study shows that LananaCreek is healthy

    First-Generation College Students & Campus Resources

    Get PDF
    The purpose of this research was to analyze how campus resources at Valparaiso University affect first-generation college students. Specifically, this study looked at the effect campus resources have on feelings of belonging on campus and academic success. First generation college students are defined as students whose parents have not obtained a four-year degree. This study used a questionnaire that was emailed to every known first-generation college student at Valparaiso University. This consisted of five sections: demographics, campus resource use, the campus community, academic preparedness, and experience. The use of campus resources section used a Likert scale to see how often students used different campus resources. The campus community and academic preparedness sections also used a Likert scale to see how much students related to questions such as, “I feel like I fit in at Valpo”. Finally, the experience section allowed for students to write in specific challenges they have faced on Valparaiso University\u27s campus. These results can help further develop the Persistence and Success Program (PSP), a first-generation college student program on campus

    Designing a task-based critical listening construct for listening assessment

    Get PDF
    This study analyzed a task-based construct of critical listening in an academic listening test for placement purposes in a North American university English for Academic Purposes program. As the ability to listen critically in English is one of the outcomes for the program, it is necessary to utilize a placement instrument that can adequately measure this ability. Buck (2001) claims that one way of approaching this idea of critical listening in listening assessment is through the use of tasks that mirror the uses and functions an examinee will encounter in authentic situations. Using Rasch model analysis, this study first examined the current form of the test to identify how items are functioning and whether or not different, distinct constructs are present in the test. The test was revised using new pilot items based on a task-based model, and then analyzed again to determine the extent this construct was represented in the instrument. Based on these analyses, recommendations are made about the effectiveness of the test and the form further revisions of the test might take in future administrations

    Measuring inconsistency in research ethics committee review

    Get PDF
    Abstract Background The review of human participant research by Research Ethics Committees (RECs) or Institutional Review Boards (IRBs) is a complex multi-faceted process that cannot be reduced to an algorithm. However, this does not give RECs/ IRBs permission to be inconsistent in their specific requirements to researchers or in their final opinions. In England the Health Research Authority (HRA) coordinates 67 committees, and has adopted a consistency improvement plan including a process called “Shared Ethical Debate” (ShED) where multiple committees review the same project. Committee reviews are compared for consistency by analysing the resulting minutes. Methods We present a description of the ShED process. We report an analysis of minutes created by research ethics committees participating in two ShED exercises, and compare them to minutes produced in a published “mystery shopper” exercise. We propose a consistency score by defining top themes for each exercise, and calculating the ratio between top themes and total themes identified by each committee for each ShED exercise. Results Our analysis highlights qualitative differences between the ShED 19, ShED 20 and “mystery shopper” exercises. The quantitative measure of consistency showed only one committee across the three exercises with more than half its total themes as top themes (ratio of 0.6). The average consistency scores for the three exercises were 0.23 (ShED19), 0.35 (ShED20) and 0.32 (mystery shopper). There is a statistically significant difference between the ShED 19 exercise, and the ShED 20 and mystery shopper exercises. Conclusions ShED exercises are effective in identifying inconsistency between ethics committees and we describe a scoring method that could be used to quantify this. However, whilst a level of inconsistency is probably inevitable in research ethics committee reviews, studies must move beyond the ShED methodology to understand why inconsistency occurs, and what an acceptable level of inconsistency might be
    corecore