2,619 research outputs found

    The NAIRU - Concept: A Few Remarks

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    This note gives a brief survey of main theoretical and empirical issues with respect to the NAIRU concept. According to modern labour market literature NAIRU is defined as the rate of unemployment at which inflation stabilizes in the absence of any wage-price surprises. Conventional thinking about the equilibrium unemployment rate assumes that in the long run NAIRU is determined solely by supply side factors of the labour market. We show that quite complex adjustment dynamics may arise even in simple log-linear wage-price models. Furthermore we provide a survey on a number of "hysteresis-mechanisms" which could lead to permanent shifts of equilibrium unemployment over time, implying that an unique long run NAIRU may not even exist. In addition to theoretical issues we refer to two serious problems which might arise with empirical applications of the NAIRU concept. First various empirical studies suggest that results highly depend on model specifications. Second a considerable amount of statistical imprecision is inherent in the results obtained from empirical estimates. For these reasons, we argue, that policy conclusions drawn from the NAIRU concept must be judged with utmost care, particularly since in many countries a number of labour market measures as well as monetary policy are based on this concept.NAIRU, Hysteresis Mechanisms

    The Potential of the Timing Method to Detect Evolved Planetary Systems

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    The timing method, using either stellar pulsations or eclipse timing of close binaries as a clock, is proving to be an efficient way to detect planets around stars that have evolved beyond the red giant branch. In this article we present a short review of the recent discoveries and we investigate the potential of the timing method using data both from ground-based facilities as well as from the Kepler and CoRoT space missions.Comment: Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.6606v1, Proc. of the workshop on "Planetary Systems beyond the Main Sequence" (Bamberg, 11-14 August 2010), AIPC in press (eds. S. Schuh, H. Drechsel and U. Heber), 15 pages, 5 figure

    Employment and Growth in an Aging Society. A Simulation Study for Austria

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    In this study we use a long run macroeconomic model for Austria to simulate the effects of aging on employment, output growth, and the solvency of the social security system. By disaggregating the population into six age cohorts and modelling sex specific participation rates for each cohort, we are able to account for the future demographic trends. Apart from a baseline scenario, we perform three alternative simulations that highlight the effects of aging from different perspectives. These include (1) purely demographic developments, (2) increasing labour market imperfections, and (3) higher economic growth due to a productivity shock.Economic growth, Aging, Austria

    News From The Gamma Cephei Planetary System

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    The Gamma Cephei planetary system is one of the most interesting systems due to several reasons: 1.) it is the first planet candidate detected by precise radial velocity (RV) measurements that was discussed in the literature (Campbell et al. 1988); 2.) it is a tight binary system with a ~ 20AU; and 3.) the planet host star is an evolved K-type star. In Hatzes et al. (2003) we confirmed the presence of the planetary companion with a minimum mass of 1.7 M_Jup at 2 AU. In this paper we present additional eight years of precise RV data from the Harlan J. Smith 2.7 m Telescope and its Tull Coude spectrograph at McDonald Observatory. The 900 d signal, that is interpreted as the presence of the giant planetary companion, is strongly confirmed by adding the new data. We present an updated orbital solution for the planet, which shows that the planet is slightly more massive and the orbit more circular than previous results have suggested. An intensive high-cadence week of RV observations in 2007 revealed that Gamma Cep A is a multi-periodic pulsator. We discuss this issue within the context of searching for additional planets in this system.Comment: Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.660

    Spectral Analysis of Mid-IR Excesses of White Dwarfs

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    In our Spitzer 24 \mu m survey of hot white dwarfs (WDs) and archival Spitzer study of pre-WDs, i.e., central stars of planetary nebulae (CSPNs), we found mid-IR excesses for -15 WDs/pre-WDs. These mid-IR excesses are indicative of the presence of circumstellar dust that could be produced by sub-planetary objects. To further assess the nature of these IR-excesses, we have obtained Spitzer IRS, Gemini NIRI and Michelle, and KPNO 4m echelle spectra of these objects. In this paper we present the analysis of these spectroscopic observations and discuss the nature of these IR excesses.Comment: Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.660

    Экспериментальные исследования двухфазных течений в разгонных трубках струйных мельниц

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    Розроблено й виготовлена осесиметричну модель ежектора струминного млина для дослідження двофазних течій у розгінній трубці струминного млина. Схема даної моделі за-снована на класичній схемі ежектора. Відмінність від класичної схеми складається в наяв-ності каналу підведення додаткового потоку. Канал підведення має кільцеву форму й забез-печує подачу рівномірно розподіленого захисного потоку в розгінний канал через щілинний отвір. Проведено дослідження на осесимметричной моделі ежектора, що складалися із декі-лькох етапів, перший з яких полягав у вивченні характеру плину основного потоку в розгінній трубці млина, другий – у виявленні впливу додаткового потоку газу на основний потік, тре-тій – у виявленні впливу додаткового потоку газу, направленого до розгінної трубки під ку-том 30. Аналіз досліджень показав, що додатковий потік газу виконує захисну функцію й запо-бігає впливу основного потоку на стінки розгінного каналу. Знайдені переваги додаткового потоку газу ,підведеного під кутом, меншим 90. Виявлено необхідність досліджувати оптимальний кут підведення додаткового пото-ку газу.Разработана и изготовлена осесимметричная модель эжектора струйной мельницы для исследования двухфазных течений в разгонной трубке струйной мельницы. Схема данной модели основана на классической схеме эжектора. Отличие от классической схемы состо-ит в наличии канала подвода дополнительного потока. Канал подвода имеет кольцевую форму и обеспечивает подачу равномерно распределенного защитного потока в разгонный канал через щелевое отверстие. Проведены исследования на осесимметричной модели эжектора, состоящие из не-скольких этапов, первый из которых заключался в изучении характера течения основного потока в разгонной трубке мельницы, второй – в выявлении влияния дополнительного пер-пендикулярного потока газа на основной поток, третий – в выявлении влияния дополни-тельного потока газа, направленного в разгонную трубку под углом 30. Анализ исследований показал, что дополнительный поток газа выполняет защитную функцию и предотвращает влияние основного потока на стенки разгонного канала. Обна-ружены преимущества дополнительного потока газа, подведенного под углом, меньшим 90. Выявлена необходимость исследовать оптимальный угол подвода дополнительного потока газа.Axisymmetric model of the jet mill ejector are designed and manufactured for studing two-phase flows in jet mill accelerating tube. The scheme of this model is based on the classical scheme of the ejector. Unlike the classical scheme is the inlet channel of an additional flow presence. A channel for supplying has an annular shape and provides the protective uniformly distributed flow in acceler-ating channel through the slotted inlet. The researches on the axisymmetric ejector model are examined. They consisted of several stages, the first of which was to examine the main flow pattern in the mill accelerating tube, the sec-ond was to identify the additional gas flow impact on the main flow, the third – to identify the impact of the additional gas flow directed at an angle of 30 degrees into the accelerating tube. Analyses of studies have shown that the additional gas flow has a protecting function and pre-vents the main flow effect on the accelerating channel walls. The benefits of the additional gas flow fed at an angle of less than 90 degrees are discovered. The need of investigating the optimum angle of the additional gas flow feed is identified

    Planets around Extreme Horizontal Branch Stars

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    We review three main results of our recent study: We show that a proper treatment of the tidal interaction prior to the onset of the common envelope (CE) leads to an enhance mass loss. This might increase the survivability of planets and brown dwarfs that enter a CE phase. From the distribution of planets around main sequence stars, we conclude that around many sdB/sdO stars more than one planet might be present. One of these might have a close orbit and the others at about orbital periods of years or more. We show that the intense ionizing flux of the extreme horizontal branch star might evaporate large quantities of a very close surviving substellar object. Balmer emission lines from the evaporated gas can be detected via their Doppler shifts.Comment: Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.660

    Verflechtungen in der österreichischen Außenwirtschaft

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    Die Analyse (mit einem "Constant Market Shares" Modell) über die Wettbewerbsfähigkeit und Struktur hat ergeben, dass sich in der österreichischen Außenwirtschaft mit Gütern in den vergangenen Jahren die Wettbewerbsfähigkeit verschlechtert hat. Es zeichnen sich auch strukturelle Probleme ab. Hier erscheint es notwendig, neue Märkte zu erobern und das Produktangebot der internationalen Nachfrageentwicklung anzupassen. Das Ergebnis der Untersuchung (mit vektorautoregressiven Prozessen) über die Zusammenhänge im österreichischen Außenhandel zeigt, dass die Exporte kleiner Dienstleistungsbranchen ein Vielfaches an Warenexporten mit sich ziehen. Signifikante Impulse kommen von der Transportbrache, von den Bau- und Finanzdienstleistungen, den EDV- und Informationsdienstleistungen, den Exporten von Patenten und Lizenzen, den sonstigen unternehmensbezogenen Dienstleistungen und vom Bereich operationales Leasing. Das Ergebnis des Gravitationsmodels ist, dass die österreichische Exportwirtschaft in Länder mit einem hohen Einkommen mehr exportiert, dass eine Verringerung der Distanz um 5 Prozent mit einer Steigerung der Exporte um 5 Prozent gerechnet werden kann und dass die Grenzen innerhalb der EU kaum handelsmindernd sind. Werden Grenzkontrollen vermindert, so wirkt sich dies positiv auf die Reiszeit aus.Competitiveness

    Ökonomische Bewertung von Instrumenten der F&E-Förderung

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    Abstract: Two modes of public funding of research and development are examined: namely indirect tax incentives and direct subsidies to private sector firms carrying out R&D. As well as considering the arguments concerning claimed advantages and disadvantages of these policy instruments, attention is paid to international experience of the effectiveness of each approach. In particular, insights are gained from a review of empirical studies of input-additionality, i.e. when public R&D spending leads to an increase of private investment. A macro-level study from the OECD presents a suitable state-of-the-art approach for comparing additionality generated by the two kinds of funding instruments. Additionality is implied in both cases, 70 percent for direct grants etc. and 32 percent for the indirect effects of tax incentives. Using these estimates the worth of long-term extra spending in Austria is around EUR 120 m for direct, and EUR 100 m for indirect R&D support.

    Searching for Planets with White Dwarf Pulsations: Spurious Detections

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    We present 13 years of pulsation timing measurements of the DBV white dwarf EC 2005-5234. Each of the four O-C diagrams mimic the sinusoidal behavior typically attributed to a planet + WD system. However, the amplitude and phase of the O-C variations are inconsistent with each other. We discuss the impact of this result on timing based WD planet searches.Comment: Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.660
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