5,913 research outputs found
Digital filter synthesis computer program
Digital filter synthesis computer program expresses any continuous function of a complex variable in approximate form as a computational algorithm or difference equation. Once the difference equation has been developed, digital filtering can be performed by the program on any input data list
Redundant actuating mechanism Patent
Design and development of release mechanism for spacecraft components, releasable despin weights, and extensible gravity boom
De Facto Judicial Independence and Physical Integrity Rights
Economists, political scientists, and legal scholars have argued that independent judiciaries have an important role to play in promoting economic development and protecting property rights. We argue that judicial independence can also have a positive impact on the protection of human rights. To assess the human rights impact of a de facto independent judiciary, we also argue that scholars must account for the potential of endogeneity between judicial independence and protection of human rights. We examine whether greater de facto independence improves government respect for citizens’ physical integrity rights, using a comprehensive dataset of 193 countries from 1981 to 2010. Employing an instrumental variables approach to control for endogeneity, we find strong support for the argument that greater levels of de facto judicial independence improve government respect for physical integrity rights. These findings are robust to changes in measurement, estimation techniques, and model specification. Failing to account for endogeneity will tend to overemphasize the ability of completely independent courts to improve government respect for physical integrity rights
EUS-Guided Pancreatic Cyst Ablation: a Clinical and Technical Review
Purpose of Review
Pancreatic cystic lesions represent a growing public health dilemma, particularly as our population ages and cross-sectional imaging becomes more sensitive. Mucinous cysts carry a clinically significant risk of developing pancreatic cancer, which carries an extremely poor prognosis. Determining which cysts will develop cancer may be challenging, and surgical resection of the pancreas carries significant morbidity. The goal of this paper is to review the rationale for cyst ablation and discuss prior and current research on cyst ablation techniques and efficacy. Indications, contraindications, and factors related to optimal patient selection are outlined.
Recent Findings
Endoscopic ultrasound-guided chemoablation of pancreatic cysts has been performed in neoplastic cysts, with varying levels of efficacy. Safety concerns arose due to the risk of pancreatitis in alcohol-based treatments; however, the most recent data using a non-alcohol chemoablation cocktail suggests that ablation is effective without the need for alcohol, resulting in a significantly more favorable adverse event profile.
Summary
Endoscopic ultrasound-guided chemoablation of neoplastic pancreatic cysts is a promising, minimally invasive approach for treatment of cysts, with recent significant advances in safety and efficacy, suggesting that it should play a role in the treatment algorithm
An investigation of small-scale motions and the forecasting of wind profiles over short periods of time at Cape Kennedy, Florida
Small scale motions and numerical wind profiles forecasting for short periods at Cape Kenned
The Cognition of Controversy: Examining Policy Elites’ Narrative Cognition and Communication Around Hydraulic Fracturing Practices in the U.S.
The use of hydraulic fracturing (HF) technologies to extract oil and gas in the United States has sparked contentious policy debates, producing inconsistent and inefficient policies that have done little to address the impacts of HF in any comprehensive way. Debates are accompanied by competing policy narratives that position HF as either an environmental threat or an economic opportunity, but little is known about how policy narratives around HF are used by individuals. This dissertation systematically examines how individuals cognitively internalize elements of competing HF policy narratives. Organized into three empirical chapters, this dissertation analyzes narrative cognition (Jones, Shanahan, and McBeth 2014) around HF, providing a rare look at policy elites, those engaged in the energy policy subsystem with the resources and potential to influence HF policy development. The first empirical chapter applies structural topic modeling to examine how policy elites cognitively internalize elements of policy narratives, finding that elite assessment of the overall utility of HF correlates with aspects of the narrative elements used to think about HF. OLS regression analysis and Bayesian Posterior Simulation results indicate that socially constructed worldviews drive policy elites’ narrative cognition in theoretically expected ways regardless of their overall perception of the utility of HF. Building on research that identifies political sophistication as fundamental to belief-driven attitudes (Michaud, Carlisle, and Smith 2009; Ripberger et al. 2012), the second empirical chapter compares cognition patterns of policy elites with members of the general public to examine the role of cognitive sophistication in elite narrative cognition. Empirical evidence supports theoretical expectations, indicating that worldviews have a stronger influence on narrative cognition for those with greater cognitive sophistication. The third empirical chapter builds on recent work by Lawlor and Crow (2018) to analyze how socially constructed risk frames support narrative cognition. Mediation analysis results indicate that socially constructed risk frames support the cognitive internalization of narrative elements and guide assessments of risk and benefit toward HF. Overall, the empirical and theoretical contributions of this dissertation deepen our understanding of policy narrative cognition and contribute to the development of several policy process theories including the Advocacy Coalition Framework, the Narrative Policy Framework, and Cultural Theory. Each empirical chapter discusses relevant practical and methodological implications of the study
Gender Differences in Preference for Learning Environment Among Aviation Education Students
This study investigated whether differences existed between sex, male and female, for the preference of three different syllabi describing three different learning environments. Learning environments consisted of collaborative, and individual, with the individual sub-divided into competitive, and individual while co-varying participants for credit hours. 264 surveys were administered to students in freshman, sophomore, junior, and senior classes in order to collect preference, and demographic data. The surveys were presented as three fictional syllabi differing only in class grading format, and a paragraph on the instructional philosophy of the professor. Instructional philosophies described the proposed environment of the class by enforcing the individual, competitive, or collaborative instructional methods. According to recent literature, women were predicted to prefer collaborative classroom environments to individual/competitive classroom environments and males were predicted to prefer competitive/individual over collaborative classroom environments. Limitations for the present study were discussed as well as suggestions for future research
Effects of Ultra-Clean and centrifugal filtration on rolling-element bearing life
Fatigue tests were conducted on groups of 65-millimeter bore diameter deep-groove ball bearings in a MIL-L-23699 lubricant under two levels of filtration. In one test series, the oil cleanliness was maintained at an exceptionally high level (better than a class "000" per NAS 1638) with a 3 micron absolute barrier filter. These tests were intended to determine the "upper limit" in bearing life under the strictest possible lubricant cleanliness conditions. In the tests using a centrifugal oil filter, contaminants of the type found in aircraft engine filters were injected into the filters' supply line at 125 milligrams per bearing-hour. "Ultra-clean" lubrication produced bearing fatigue lives that were approximately twice that obtained in previous tests with contaminated oil using 3 micron absolute filtration and approximately three times that obtained with 49 micron filtration. It was also observed that the centrifugal oil filter had approximately the same effectiveness as a 30 micron absolute filter in preventing bearing surface damage
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