2,261 research outputs found
Global Epidemiology of Lung Cancer.
While lung cancer has been the leading cause of cancer-related deaths for many years in the United States, incidence and mortality statistics - among other measures - vary widely worldwide. The aim of this study was to review the evidence on lung cancer epidemiology, including data of international scope with comparisons of economically, socially, and biologically different patient groups. In industrialized nations, evolving social and cultural smoking patterns have led to rising or plateauing rates of lung cancer in women, lagging the long-declining smoking and cancer incidence rates in men. In contrast, emerging economies vary widely in smoking practices and cancer incidence but commonly also harbor risks from environmental exposures, particularly widespread air pollution. Recent research has also revealed clinical, radiologic, and pathologic correlates, leading to greater knowledge in molecular profiling and targeted therapeutics, as well as an emphasis on the rising incidence of adenocarcinoma histology. Furthermore, emergent evidence about the benefits of lung cancer screening has led to efforts to identify high-risk smokers and development of prediction tools. This review also includes a discussion on the epidemiologic characteristics of special groups including women and nonsmokers. Varying trends in smoking largely dictate international patterns in lung cancer incidence and mortality. With declining smoking rates in developed countries and knowledge gains made through molecular profiling of tumors, the emergence of new risk factors and disease features will lead to changes in the landscape of lung cancer epidemiology
Signaling Virtue or Vulnerability? The Changing Impact of Exchange Rate Regimes on Government Bond Yields
Do exchange rate regimes affect the conditions under which developed countries borrow? This paper argues that they do, but their impact on yields depends on the prevailing macroeconomic context. When investors regard inflation as the most relevant risk to bond holdings, monetary union has a distinct advantage over floating and fixed exchange rates because of its credible in-built mechanism to control inflation. However, once default is seen as the most relevant risk, exchange rate rigidity becomes a liability due to its constraining effect on governments’ ability to respond to adverse shocks. We test our argument with a moving window panel analysis for twenty-three OECD countries from 1980 to 2017. We find that before the late 2000s, inflation was penalized under floating and (to a lesser extent) fixed exchange rate regimes, but not in countries in monetary union. Since the 2010s, inflation carries no penalty under any exchange rate regime. Variables linked to default risk (debt and entitlement spending) did not affect yields under any exchange rate arrangements until the mid-2000s. Afterwards, countries in monetary union (and to a lesser extent in fixed exchange rate regimes) were significantly penalized for public debt and entitlement spending, whereas countries with floating regimes were not. Our results speak to the literatures on governments’ institutional commitments and “room to move.”Haben Wechselkursregime einen Einfluss auf die Konditionen, zu denen entwickelte Länder Staatsanleihen ausgeben können? Wir argumentieren in diesem Beitrag, dass dies der Fall ist, wobei ihre Wirkung auf die Anleiherenditen vom vorherrschenden makroökonomischen Kontext abhängt. Erachten Investoren Inflation als das entscheidende Risiko für Investitionen in Anleihen, so hat eine Währungsunion durch ihren glaubwürdigen integrierten Mechanismus zur Inflationskontrolle klare Vorteile gegenüber flexiblen und festen Wechselkursen. Wird jedoch ein Ausfall der Rückzahlungen als das entscheidende Risiko angesehen, werden starre Wechselkurse zum Nachteil, da sie die Fähigkeit von Regierungen, auf negative Schocks zu reagieren, verringern. Wir testen unser Argument mithilfe einer für den Zeitraum von 1980 bis 2017 mit gleitenden Zeitfenstern durchgeführten Panelanalyse von 23 OECD-Ländern. Die Ergebnisse zeigen, dass Inflation vor den späten 2000er-Jahren in flexiblen und (weniger stark) in festen Wechselkursregimen finanziell abgestraft wurde, jedoch nicht in den Ländern einer Währungsunion. Seit den 2010er-Jahren wirkt sich Inflation in keinem der Wechselkursregime auf die Renditen aus. Mit dem Ausfallrisiko verknüpfte Variablen (Staatsverschuldung und Sozialausgaben) hatten bis zur Mitte der 2000er-Jahre in keinem der Wechselkursregime einen Einfluss auf die Renditen. Danach wurden Länder in einer Währungsunion erheblich (und Länder in festen Wechselkursregimen weniger stark) für Staatsverschuldung und Sozialausgaben abgestraft, während dies bei Ländern in flexiblen Regimen nicht der Fall war. Unsere Ergebnisse tragen zur Literatur über institutionelle Selbstverpflichtungen und Handlungsspielräume von Regierungen bei.Contents 1 Introduction 2 Commitment devices and policy autonomy from a theoretical perspective 3 Inflation risk, default risk, and exchange rate regimes: An analysis of twenty-three OECD countries 4 Results section Results Robustness checks 5 Discussion and conclusion Appendix A Sources used for identifying sample countries’ exchange rate regimes over time Appendix B Results controlling for capital mobility (measured via the Chinn-Ito capital account openness index) Appendix C Results excluding countries with a greater share of foreign currency-denominated debt than 2 percent (Canada and Sweden) Appendix D Results for crawling peg exchange rate regime Appendix E Results excluding heavily indebted EMU countries (Belgium, Greece, and Italy) Appendix F Results excluding EMU countries with the lowest sovereign credit ratings prior to the crisis (Greece, Italy, and Portugal) Reference
Perceptions of Incivility Among Students and Faculty in Entry-Level Health Professional Programs
Purpose: Online education is growing in popularity but has the potential to result in cyber incivility leading to disruptions in the learning environment. There is little known about the differences in attitudes between students and faculty in the online learning experience regarding cyber civility. The purpose of this study was to analytically measure student and faculty perceptions and attitudes of cyber incivility. Methods: A convenience sample of 180 (34 faculty and 146 students) participants from a health care university were recruited. A 27-item survey was given to record the perceptions of students and faculty on issues of cyber civility. An exploratory factor analysis was completed to validate the survey tool and determine the factors that made up the survey. A Mann Whitney U test was conducted to determine significant differences between student and faculty perceptions on the survey items. Results: Four factors were identified of the retained 19 items after the exploratory factor analysis: attitudes, presentation, appearance, and multitasking. There was a significant difference on 10 of the remaining survey items between students and faculty. Conclusions: Faculty perceived unprofessional dress, multitasking, and active display of complaints in the virtual environment more uncivil and disruptive than students. The themes show the differences between students and faculty perceptions in online platforms in healthcare educational programs. These differences highlight the need for healthcare educational programs to focus on strategies that align student and faculty expectations to positively impact the dynamics of the class and enhance learning in the virtual environment
Experimental Analysis and Design Improvements on Combined Viper Expansion Work Recovery Turbine and Flow Phase Separation Device Applied in R410A Heat Pump
In light of recent trends towards energy efficiency and environmental consciousness, the heating, ventilation, air conditioning and refrigeration (HVAC&R) industry has been pushing for technological developments to meet both of these needs. As such, several solutions for harnessing the energy released from refrigerants during the expansion process of a conventional vapor-compression cycle have been developed to increase overall cycle efficiency. The study presented in this paper focuses on investigating the potential impact of installing an energy recovery expansion device known as the Viper Expander into an R410A heat pump. The Viper Expander operates by using a nozzle to accelerate the high pressure R410A into a high velocity jet of fluid impinging on a micro-turbine impeller. The impeller is coupled to a generator, which harvests the kinetic energy of the refrigerant by converting it into electrical energy that can be fed back into one of the system components, such as a fan or compressor motor. Previous Viper Expander iterations have not met performance expectations and thus, a major redesign was pursued. To improve the Viper Expander design, flow visualization of the two-phase refrigerant leaving the nozzle has been performed. Additionally, a housing redesign that will allow the Viper Expander to act as both an expansion work recovery device as well as a flash tank economizer has been proposed and modeled as a system solution
Numerical Analysis of Active Flow Boiling Regime Management Using a Vapor-Compression Cycle Applied to Electronic Processor Cooling
As computing power continues to grow at a rapid rate, the thermal load generated from electronic devices follows. Furthermore, reduced size requirements for electronic devices have driven engineers to produce this increased computing power in smaller packaging than ever before. The combination of these two trends results in high heat flux processors that require innovative cooling techniques. Industry and academia alike have anticipated this trend and have developed several general families of solutions to cooling high-heat flux processors. This work proposes the use of flow boiling in a vapor compression cycle and a spreader to distribute the heat from a high-heat flux source to the evaporator. Specifically, the balance between cycle performance and achievable heat flux is assessed, and operating conditions where the ability of the cycle to control evaporator heat flux and simultaneously achieve a high cycle efficiency are identified. A numerical flow boiling correlation is applied and a microchannel evaporator design model is proposed. Geometric parameters and performance limitations of this technique are analyzed and both quantitative and qualitative results along with future work are presented
Modeling of S-RAM Energy Recover Compressor Integration in a Transcritical Carbon Dioxide Cycle for Application in Electronics Cooling in Varying Gravity
As electronics in military aircraft become increasingly complicated, additional cooling is necessary to enable efficient and high computing performance. Additionally, the varying forces that a military aircraft endure during maneuvering and inverted flight introduce unique design constraints to the electronics cooling systems. Because this cooling system will be in an aircraft, the capacity and unique design constraints must all be met with a design that is as lightweight as possible. This paper presents a study comparing the coefficient of performance (COP) of several cycle architectures with both R134a and carbon dioxide ( ). Cycles with single-stage and two-stage compression with intercooling are compared, and both are modeled with suction-to-liquid line heat exchangers. The cycles utilizing are transcritical in order to reach the required temperatures for heat rejection from the gas cooler. Additionally, cycles with expansion work recovery and an ejector are compared. The cooling requirements are up to 150 kW with a heat source temperature as low as and a heat sink temperature of up to . The purpose of this analysis is to understand which of the above cycles performs with the highest efficiency for the given electronics cooling application
Evaluation of an online fermentation monitoring system
The need to introduce promising bioethanol production technologies calls for advanced laboratory techniques to study experiment designs and to obtain their results in a quick and reliable way. Real time monitoring based on general principles of ethanol fermentation, such as effluent CO2 volume, avoids time consuming steps, long lasting analyses and delivers information about the process directly. A device based on the above features and capable for real time monitoring on parallel channels was developed by the authors and is described in this paper. Both for calibration and for fermentation, test runs were carried out on different days and channels. Statistical evaluation was based on the obtained data. According to the t-test (P=0.05) and Grubbs analysis, the calibration method is reliable regardless of the date of calibration. When evaluating the fermentation results by ANCOVA acceptable standard derivations were obtained as impact of channel (58.8 ml), date (82.1 ml) and incorporating all impacts (116.2 ml). The final ethanol concentrations calculated based on the gas volume were compared to ones determined by HPLC and an average difference of 10% was found. Thus, the device proved to be advantageous in monitoring fermentation
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