Jet Injection Used to Control Rotating Stall in a High-Speed Compressor

In a joint effort between the Massachusetts Institute of Technology (MIT) and the NASA Lewis Research Center, a new technology was demonstrated to identify and control rotating stall and surge in a single-stage, high-speed compressor. Through the use of highvelocity, high-frequency jet injectors, the instabilities of surge and stall were controlled in a high-speed compressor rig. Through the use of active stall control, modal instabilities that normally occur in the pressure measurements prior to stall were normalized and the range of the compressor was extended. Normally the events of rotating stall and surge instabilities limit the operation of the aeroengine compressor to a region below the surge line. To enhance the performance of the compressor, the Lewis/MIT team used active stall control methods to extend the normal operation of the compressor beyond the original stall point

Purification of a Crenarchaeal ATP Synthase in the Light of the Unique Bioenergetics of Ignicoccus Species

In this study, the ATP synthase of Ignicoccus hospitalis was purified, characterized, and structurally compared to the respective enzymes of the other Ignicoccus species, to shed light on energy conservation in this unique group of archaea. The crenarchaeal genus Ignicoccus comprises three described species, i.e., I. hospitalis and Ignicoccus islandicus from hot marine sediments near Iceland and Ignicoccus pacificus from a hydrothermal vent system in the Pacific Ocean. This genus is unique among all archaea due to the unusual cell envelope, consisting of two membranes that enclose a large intermembrane compartment (IMC). I. hospitalis is the best studied member of this genus, mainly because it is the only known host for the potentially parasitic archaeon Nanoarchaeum equitans. I. hospitalis grows chemolithoautotrophically, and its sole energy-yielding reaction is the reduction of elemental sulfur with molecular hydrogen, forming large amounts of hydrogen sulfide. This reaction generates an electrochemical gradient, which is used by the ATP synthase, located in the outer cellular membrane, to generate ATP inside the IMC. The genome of I. hospitalis encodes nine subunits of an A-type ATP synthase, which we could identify in the purified complex. Although the maximal in vitro activity of the I. hospitalis enzyme was measured around pH 6, the optimal stability of the A(1)A(O) complex seemed to be at pH 9. Interestingly, the soluble A(1) subcomplexes of the different Ignicoccus species exhibited significant differences in their apparent molecular masses in native electrophoresis, although their behaviors in gel filtration and chromatography-mass spectrometry were very similar. IMPORTANCE The Crenarchaeota represent one of the major phyla within the Archaea domain. This study describes the successful purification of a crenarchaeal ATP synthase. To date, all information about A-type ATP synthases is from euryarchaeal enzymes. The fact that it has not been possible to purify this enzyme complex from a member of the Crenarchaeota until now points to significant differences in stability, possibly caused by structural alterations. Furthermore, the study subject I. hospitalis has a particular importance among crenarchaeotes, since it is the only known host of N. equitans. The energy metabolism in this system is still poorly understood, and our results can help elucidate the unique relationship between these two microbes

From Empire to Republic

After the dissolution of the Austro-Hungarian Monarchy, Austria transformed itself from an empire to a small Central European country. Formerly an important player in international affairs, the new republic was quickly sidelined by the European concert of powers. The enormous losses of territory and population in Austria's post-Habsburg state of existence, however, did not result in a political, economic, cultural, and intellectual black hole. The essays in the twentieth anniversary volume of Contemporary Austrian Studies argue that the small Austrian nation found its place in the global arena of the twentieth century and made a mark both on Europe and the world. Be it Freudian psychoanalysis, the “fin-de-siècle” Vienna culture of modernism, Austro-Marxist thought, or the Austrian School of Economics, Austrian hinkers and ideas were still wielding a notable impact on the world. Alongside these cultural and intellectual dimensions, Vienna remained the Austrian capital and reasserted its strong position in Central European and international business and finance. Innovative Austrian companies are operating all over the globe. This volume also examines how the globalizing world of the twentieth century has impacted Austrian demography, society, and political life. Austria's place in the contemporary world is increasingly determined by the forces of the European integration process. European Union membership brings about convergence and a regional orientation with ramifications for Austria's global role. Austria emerges in the essays of this volume as a highly globalized country with an economy, society, and political culture deeply grounded in Europe. The globalization of Austria, it appears, turns out to be in many instances an “Europeanization”.Der Zerfall der Österreichisch-Ungarischen Monarchie hatte zur Folge, dass die einstige Großmacht der Habsburger zu einem Kleinstaat im Herzen Europa wurde. Der enorme Verlust an Territorium und die Verringerung der Bevölkerung hinterließ allerdings keineswegs ein politisches, wirtschaftliches, kulturelles oder intellektuelles Vakuum. Die Aufsätze des 20. Jubiläumsbandes der Contemporary Austrian Studies zeigen vielmehr, dass die Republik Österreich ihren Platz in Europa und der Welt halten konnte: Sei es die Psychoanalyse von Freud, das Wien des fin-de-siècle oder der Austro-Marxismus, österreichische Ideen fanden weltweit Anklang. Auch in der internationalen Geschäfts- und Finanzwelt konnte sich Wien als Hauptstadt behaupten. Heute bestimmen der EU-Beitritt, der europäische Integrationsprozess sowie die Globalisierung das wirtschaftliche, gesellschaftliche und politische Leben Österreichs

From Empire to Republic

After the dissolution of the Austro-Hungarian Monarchy, Austria transformed itself from an empire to a small Central European country. Formerly an important player in international affairs, the new republic was quickly sidelined by the European concert of powers. The enormous losses of territory and population in Austria's post-Habsburg state of existence, however, did not result in a political, economic, cultural, and intellectual black hole. The essays in the twentieth anniversary volume of Contemporary Austrian Studies argue that the small Austrian nation found its place in the global arena of the twentieth century and made a mark both on Europe and the world. Be it Freudian psychoanalysis, the “fin-de-siècle” Vienna culture of modernism, Austro-Marxist thought, or the Austrian School of Economics, Austrian hinkers and ideas were still wielding a notable impact on the world. Alongside these cultural and intellectual dimensions, Vienna remained the Austrian capital and reasserted its strong position in Central European and international business and finance. Innovative Austrian companies are operating all over the globe. This volume also examines how the globalizing world of the twentieth century has impacted Austrian demography, society, and political life. Austria's place in the contemporary world is increasingly determined by the forces of the European integration process. European Union membership brings about convergence and a regional orientation with ramifications for Austria's global role. Austria emerges in the essays of this volume as a highly globalized country with an economy, society, and political culture deeply grounded in Europe. The globalization of Austria, it appears, turns out to be in many instances an “Europeanization”.Der Zerfall der Österreichisch-Ungarischen Monarchie hatte zur Folge, dass die einstige Großmacht der Habsburger zu einem Kleinstaat im Herzen Europa wurde. Der enorme Verlust an Territorium und die Verringerung der Bevölkerung hinterließ allerdings keineswegs ein politisches, wirtschaftliches, kulturelles oder intellektuelles Vakuum. Die Aufsätze des 20. Jubiläumsbandes der Contemporary Austrian Studies zeigen vielmehr, dass die Republik Österreich ihren Platz in Europa und der Welt halten konnte: Sei es die Psychoanalyse von Freud, das Wien des fin-de-siècle oder der Austro-Marxismus, österreichische Ideen fanden weltweit Anklang. Auch in der internationalen Geschäfts- und Finanzwelt konnte sich Wien als Hauptstadt behaupten. Heute bestimmen der EU-Beitritt, der europäische Integrationsprozess sowie die Globalisierung das wirtschaftliche, gesellschaftliche und politische Leben Österreichs

Measuring everyday functional competence using the Rasch assessment of everyday activity limitations (REAL) item bank

Objective: Traditional patient-reported physical function instruments often poorly differentiate patients with mild-to-moderate disability. We describe the development and psychometric evaluation of a generic item bank for measuring everyday activity limitations in outpatient populations. Study design and setting: Seventy-two items generated from patient interviews and mapped to the International Classification of Functioning, Disability and Health (ICF) domestic life chapter were administered to 1128 adults representative of the Dutch population. The partial credit model was fitted to the item responses and evaluated with respect to its assumptions, model fit, and differential item functioning (DIF). Measurement performance of a computerized adaptive testing (CAT) algorithm was compared with the SF-36 physical functioning scale (PF-10). Results: A final bank of 41 items was developed. All items demonstrated acceptable fit to the partial credit model and measurement invariance across age, sex, and educational level. Five- and ten-item CAT simulations were shown to have high measurement precision, which exceeded that of SF-36 physical functioning scale across the physical function continuum. Floor effects were absent for a 10-item empirical CAT simulation, and ceiling effects were low (13.5%) compared with SF-36 physical functioning (38.1%). CAT also discriminated better than SF-36 physical functioning between age groups, number of chronic conditions, and respondents with or without rheumatic conditions. Conclusion: The Rasch assessment of everyday activity limitations (REAL) item bank will hopefully prove a useful instrument for assessing everyday activity limitations. T-scores obtained using derived measures can be used to benchmark physical function outcomes against the general Dutch adult population