Media Ecologies

In this chapter, we frame the media ecologies that contextualize the youth practices we describe in later chapters. By drawing from case studies that are delimited by locality, institutions, networked sites, and interest groups (see appendices), we have been able to map the contours of the varied social, technical, and cultural contexts that structure youth media engagement. This chapter introduces three genres of participation with new media that have emerged as overarching descriptive frameworks for understanding how youth new media practices are defi ned in relation and in opposition to one another. The genres of participation—hanging out, messing around, and geeking out—refl ect and are intertwined with young people’s practices, learning, and identity formation within these varied and dynamic media ecologies

An investigation of hydraulic-line resonance and its attenuation

An investigation of fluid resonance in high-pressure hydraulic lines has been made with two types of fluid dampers (or filters) installed in the line. One type involved the use of one or more closed-end tubes branching at right angles from a main line, and the other type was a fluid muffler installed in-line. These devices were evaluated in forced vibration tests with oscillatory disturbances over a 1000-Hz range applied to one end of the line and with oscillatory pressures measured at various stations along the main pipe. Limited applications of acoustic-wave theory to the branched systems are also included. Results show varying attenuations of pressure perturbations, depending on the number and location of branches and the type of muffler. Up to three branches were used in the branch-resonator study, and the largest frequency range with maximum attenuation was obtained for a three-branch configuration. The widest frequency ranges with significant attenuations were obtained with two types of fluid mufflers

Trailing Edge Noise Reduction by Passive and Active Flow Controls

This paper presents the results on the use of porous metal foams (passive control) and dielectric barrier surface plasma actuations (active control) for the reduction of vortex shedding tonal noises from the nonflat plate type trailing edge serration in a NACA0012 airfoil previously discussed in Chong et al. (AIAA J. Vol. 51, 2013, pp. 2665-2677). The use of porous metal foams to fill the interstices between adjacent members of the sawtooth can almost completely suppress the vortex shedding tonal noise, whilst the serration effect on the broadband noise reduction is retained. This concept will promote the nonflat plate type serrated trailing edge to become a genuine alternative to the conventional flat plate type serrated trailing edge, which is known to have drawbacks in the structural stability, aerodynamic performances and implementation issues. For the plasma actuators, configuration which produces electric wind in a tangential direction is found to be not very effective in suppressing the vortices emanated from the serration blunt root. On the other hand, for the plasma configuration which produces electric wind in a vertical direction, good level of vortex shedding tonal noise reduction has been demonstrated. However, the self noise produced by the plasma actuators negates the noise benefits on the tonal noise reduction. This characteristic illustrates the need to further develop the plasma actuators in a two pronged approach. First is to increase the electric wind speed, thereby allowing the plasma actuators to be used in a higher free jet velocity which naturally produces a larger level of jet noise. Second, the self noise radiated by the plasma actuators should be reduced

Acute and Chronic Effects of Smoking on Inflammation Markers in Exhaled Breath Condensate in Current Smokers

Background: Long-term cigarette smoking is associated with pulmonary inflammation, but the acute effects of smoking have been less well studied. Analysis of the exhaled breath condensate (EBC) can provide noninvasive markers that might be indicative of inflammation. Objectives: The aim of the study was to determine whether the pH, electrical conductivity and the levels of ammonium and interleukin 8 (IL-8) of EBC were altered in smokers and whether they changed after smoking a single cigarette. Methods: We included 19 healthy nonsmokers (controls), 29 asymptomatic smokers, 10 patients with stable chronic obstructive pulmonary disease (COPD) {[}Global Initiative for Chronic Obstructive Lung Disease stages (GOLD) stages II-III], and 10 patients with exacerbated COPD. In 13 smokers, EBC was also analyzed before and after smoking. EBC was obtained during 10 min tidal breathing with a cooled RTube (TM). pH was determined after deaeration with argon. Results: Acute smoking did not alter the pH or ammonium and IL-8 levels, but raised conductivity. As in COPD patients, the pH was significantly decreased in chronic smokers with a history of at least 10 pack-years compared to controls. Conclusions: EBC can be used to detect the acute and chronic effects of smoking. The increased conductivity of EBC after smoking suggests acute inflammatory effects. The reduced pH in chronic smokers shows cigarette-induced inflammation. Copyright (C) 2009 S. Karger AG, Base

Lohnpolitik heute

Makroökonomisch orientierte Lohnpolitik war weitgehend aus der Mode gekommen. Vorherrschend war vielmehr die Ansicht, dass die Lohnfindung ein Marktprozess wie jeder andere sei. Diese theoretischen Vorstellungen vernachlässigen jedoch wesentliche Aspekte der Lohnbildung. So wird ihre gesamtwirtschaftliche Dimension völlig übersehen. Die Lohnbildung hat aber über ihre Einkommenswirkung und über ihre Verteilungswirkung direkten Einfluss auf die Binnennachfrage. Seit Beginn der Europäischen Währungsunion (EWU) ist ein weiterer wesentlicher, gesamtwirtschaftlicher Aspekt hinzugekommen. Mit der Abschaffung der Wechselkurse stellt sich das Problem struktureller Leistungsbilanzungleichgewichte als Folge unterschiedlicher Wettbewerbsbedungen in den Volkswirtschaften der einzelnen Mitgliedsstaaten. Die Löhne sind hierfür ein wesentlicher Faktor. Im Folgenden wird ein lohnpolitisches Konzept entwickelt, das all diesen Anforderungen Rechnung trägt.Macro-economically oriented wage policies have largely been out of fashion. The predominant view has been that wage bargaining is a market process like any other. Consequently, these theoretical considerations neglect essential aspects of the wage formation process. For example, the macroeconomic dimension is completely overlooked. Wages, however, by influencing the level of income and its distribution, have direct effects on domestic demand. Furthermore, the European Monetary Union (EMU) adds another important macroeconomic component: the abolition of exchange rates poses the problem of structural current-account imbalances in the economies of the member states resulting from differences in competitiveness. Wages are thus a major factor contributing to the imbalances. In the following, we present a wage policy concept that accounts for all these macroeconomic aspects

Temporal Variability of Urinary Phthalate Metabolite Levels in Men of Reproductive Age

Phthalates are a family of multifunctional chemicals widely used in personal care and other consumer products. The ubiquitous use of phthalates results in human exposure through multiple sources and routes, including dietary ingestion, dermal absorption, inhalation, and parenteral exposure from medical devices containing phthalates. We explored the temporal variability over 3 months in urinary phthalate metabolite levels among 11 men who collected up to nine urine samples each during this time period. Eight phthalate metabolites were measured by solid-phase extraction–high-performance liquid chromatography–tandem mass spectrometry. Statistical analyses were performed to determine the between- and within-subject variance apportionment, and the sensitivity and specificity of a single urine sample to classify a subject’s 3-month average exposure. Five of the eight phthalates were frequently detected. Monoethyl phthalate (MEP) was detected in 100% of samples; monobutyl phthalate, monobenzyl phthalate, mono-2-ethylhexyl phthalate (MEHP), and monomethyl phthalate were detected in > 90% of samples. Although we found both substantial day-to-day and month-to-month variability in each individual’s urinary phthalate metabolite levels, a single urine sample was moderately predictive of each subject’s exposure over 3 months. The sensitivities ranged from 0.56 to 0.74. Both the degree of between- and within-subject variance and the predictive ability of a single urine sample differed among phthalate metabolites. In particular, a single urine sample was most predictive for MEP and least predictive for MEHP. These results suggest that the most efficient exposure assessment strategy for a particular study may depend on the phthalates of interest