Self-gravitating Newtonian disks revisited

Recent analytic results concerning stationary, self-gravitating fluids in Newtonian theory are discussed. We give a theorem that forbids infinitely extended fluids, depending on the assumed equation of state and the rotation law. This part extends previous results that have been obtained for static configurations. The second part discusses a Sobolev bound on the mass of the fluid and a rigorous Jeans-type inequality that is valid in the stationary case.Comment: A talk given at the Spanish Relativity Meeting in Portugal 2012. To appear in Progress in Mathematical Relativity, Gravitation and Cosmology, Proceedings of the Spanish Relativity Meeting ERE2012, University of Minho, Guimaraes, Portugal, 3-7 September 2012, Springer Proceedings in Mathematics & Statistics, Vol. 6

Job Creation, Destruction and Transition in Poland, 1988-1998: Panel Evidence

Longitudinal data from interviews with Poles of working age conducted in 1988, 1993 and 1998 present a detailed view of the transition from a state dominated to a market economy. Job loss in state firms and job creation in new private firms are the dominant employment change, other than retirements from the labor force. In the Polish case, a significant proportion of this movement over the 1988 to 1998 period involves a period of unemployment or exit from the labor force before obtaining a private sector job. A second feature of the Polish transition is considerable job competition between workers leaving the state sector and those who were out of the labor force at the beginning of the transition. The likelihood of moving to the private sector was higher for the better educated and for residents of regions with a robust de novo economy, suggesting that the supply of jobs in the private sector combined with higher levels of human capital lead to faster and smoother transitions. Lastly, wage differences between the state sector and the de novo sector appear to have little association with mobility, suggesting that movement is not strongly related to the opportunity to find a higher paying job.http://deepblue.lib.umich.edu/bitstream/2027.42/39887/3/wp502.pd

Politicians in times of transformation: "Transformational correctness" or genuine differences in perception?

The paper presents selected results of the 1996 study of top Polish politicians-members of the 1993-97 Parliament and leaders of those important political parties which failed to get into this Parliament. Presented results pertain to five aspects of politicians' attitudes: (1) opinions on qualities of persons who should be vs. actually are involved in politics, (2) normatively accepted definitions of politics, (3) visions of the good state, (4) visions of democracy, and (5) opinions on what defines political views as being either on the left or on the right. As a result, consistently found across all five domains, there is a strong attitudinal similarity among politicians of differing political parties and of divergent political orientations. This finding is interpreted as reflection of a fundamental track similarity in the way in which Polish politicians perceive the most important tasks confronting the whole political class in times of systemic transformation. Transformational correctness - believing that in such times politicians should have (or at least should display) certain views - might be a strong force behind this similarity. --

Investigation of low-cost fabrication of ablative heat shields

The fabrication, testing, and evaluation of materials and techniques employed in the fabrication of ablative heat shield panels are described. Results of this effort show projected reductions in labor man-hours for dielectric curing of panels when compared to panels molded in a steam-heated press. In addition, panels were fabricated with more than one density within the cross-section. These dual-density panels show significant weight and cost reduction potentials

On the stability of self-gravitating accreting flows

Analytic methods show stability of the stationary accretion of test fluids but they are inconclusive in the case of self-gravitating stationary flows. We investigate numerically stability of those stationary flows onto compact objects that are transonic and rich in gas. In all studied examples solutions appear stable. Numerical investigation suggests also that the analogy between sonic and event horizons holds for small perturbations of compact support but fails in the case of finite perturbations.Comment: 10 pages, accepted for publication in PR

Politicians in times of transformation: "transformational correctness" or genuine differences in perception?

"The paper presents selected results of the 1996 study of top Polish politicians members of the 1993-97 Parliament and leaders of those important political parties which failed to get into this Parliament. Presented results pertain to five aspects of politicians' attitudes: (1) opinions on qualities of persons who should be vs. actually are involved in politics, (2) normatively accepted definitions of politics, (3) visions of the 'good state', (4) visions of democracy, and (5) opinions on what defines political views as being either on the 'left' or on the 'right.' As a result, consistently found across all five domains, there is a strong attitudinal similarity among politicians of differing political parties and of divergent political orientations. This finding is interpreted as reflection of a fundamental 'track similarity' in the way in which Polish politicians perceive the most important tasks confronting the whole political class in times of systemic transformation. 'Transformational correctness' - believing that in such times politicians should have (or at least should display) certain views - might be a strong force behind this similarity." (author's abstract)Es werden ausgewählte Ergebnisse einer größeren Untersuchung maßgeblicher polnischer Politiker präsentiert, und zwar von Mitgliedern des Parlaments von 1993 bis 1997 und Führern von wichtigeren politischen Parteien, die den Einzug in dieses Parlament nicht schafften. Die Untersuchung bezieht sich auf fünf Aspekte der Einstellungen der Politiker: (1) Meinungen über die Eigenschaften von Personen, die in der Politik tätig sein sollten oder es tatsächlich sind; (2) normativ akzeptierte Definitionen von Politik; (3) Vorstellungen vom "guten Staat"; (4) Vorstellungen von Demokratie; (5) Meinungen über die Einstufung politischer Anschauungen als eher "rechts" oder eher "links". Als Gesamtergebnis stellt sich, und zwar konsistent auf sämtlichen fünf Fragegebieten, eine starke Ähnlichkeit in den Einstellungen von Politikern heraus - über unterschiedliche politische Parteien und divergierende politische Orientierungen hinweg. Die Autoren finden hierin eine grundlegende "Verlaufsähnlichkeit" dahingehend widergespiegelt, wie polnische Politiker die wichtigsten Aufgaben wahrnehmen, die der Politik in Zeiten systemischer Transformation gestellt sind. Als starke Kraft hinter dieser Ähnlichkeit wird ein Phänomen "transformationeller Korrektheit" gesehen - die Überzeugung, daß in derartigen Veränderungszeiten ein Politiker bestimmte Auffassungen haben (oder sie zumindest zum Ausdruck bringen) sollte. (HH

Politicians in times of transformation: "Transformational correctness" or genuine differences in perception?

The paper presents selected results of the 1996 study of top Polish politicians-members of the 1993-97 Parliament and leaders of those important political parties which failed to get into this Parliament. Presented results pertain to five aspects of politicians' attitudes: (1) opinions on qualities of persons who should be vs. actually are involved in politics, (2) normatively accepted definitions of politics, (3) visions of the good state, (4) visions of democracy, and (5) opinions on what defines political views as being either on the left or on the right. As a result, consistently found across all five domains, there is a strong attitudinal similarity among politicians of differing political parties and of divergent political orientations. This finding is interpreted as reflection of a fundamental track similarity in the way in which Polish politicians perceive the most important tasks confronting the whole political class in times of systemic transformation. Transformational correctness - believing that in such times politicians should have (or at least should display) certain views - might be a strong force behind this similarity

Cosmological gravitomagnetism and Mach's principle

The spin axes of gyroscopes experimentally define local non-rotating frames. But what physical cause governs the time-evolution of gyroscope axes? We consider linear perturbations of Friedmann-Robertson-Walker cosmologies with k=0. We ask: Will cosmological vorticity perturbations exactly drag the spin axes of gyroscopes relative to the directions of geodesics to quasars in the asymptotic unperturbed FRW space? Using Cartan's formalism with local orthonormal bases we cast the laws of linear cosmological gravitomagnetism into a form showing the close correspondence with the laws of ordinary magnetism. Our results, valid for any equation of state for cosmological matter, are: 1) The dragging of a gyroscope axis by rotational perturbations of matter beyond the Hubble-dot radius from the gyroscope is exponentially suppressed, where dot is the derivative with respect to cosmic time. 2) If the perturbation of matter is a homogeneous rotation inside some radius around a gyroscope, then exact dragging of the gyroscope axis by the rotational perturbation is reached exponentially fast as the rotation radius grows beyond the H-dot radius. 3) For the most general linear cosmological perturbations the time-evolution of all gyroscope spin axes exactly follow a weighted average of the energy currents of cosmological matter. The weight function is the same as in Ampere's law except that the inverse square law is replaced by the Yukawa force with the Hubble-dot cutoff. Our results demonstrate (in first order perturbation theory for FRW cosmologies with k = 0) the validity of Mach's hypothesis that axes of local non-rotating frames precisely follow an average of the motion of cosmic matter.Comment: 18 pages, 1 figure. Comments and references adde