The bearable lightness of being

How are philosophical questions about what kinds of things there are to be understood and how are they to be answered? This paper defends broadly Fregean answers to these questions. Ontological categories-such as object, property, and relation-are explained in terms of a prior logical categorization of expressions, as singular terms, predicates of varying degree and level, etc. Questions about what kinds of object, property, etc., there are are, on this approach, reduce to questions about truth and logical form: for example, the question whether there are numbers is the question whether there are true atomic statements in which expressions function as singular terms which, if they have reference at all, stand for numbers, and the question whether there are properties of a given type is a question about whether there are meaningful predicates of an appropriate degree and level. This approach is defended against the objection that it must be wrong because makes what there depend on us or our language. Some problems confronting the Fregean approach-including Frege's notorious paradox of the concept horse-are addressed. It is argued that the approach results in a modest and sober deflationary understanding of ontological commitments

Evolution of the Pairwise Peculiar Velocity Distribution Function in Lagrangian Perturbation Theory

The statistical distribution of the radial pairwise peculiar velocity of galaxies is known to have an exponential form as implied by observations and explicitly shown in N-body simulations. Here we calculate its statistical distribution function using the Zel'dovich approximation assuming that the primordial density fluctuations are Gaussian distributed. We show that the exponential distribution is realized as a transient phenomena on megaparsec scales in the standard cold-dark-matter model.Comment: 19 pages, 8 Postscript figures, AAS LaTe

Delayed feedback as a means of control of noise-induced motion

Time--delayed feedback is exploited for controlling noise--induced motion in coherence resonance oscillators. Namely, under the proper choice of time delay, one can either increase or decrease the regularity of motion. It is shown that in an excitable system, delayed feedback can stabilize the frequency of oscillations against variation of noise strength. Also, for fixed noise intensity, the phenomenon of entrainment of the basic oscillation period by the delayed feedback occurs. This allows one to steer the timescales of noise-induced motion by changing the time delay.Comment: 4 pages, 4 figures. In the replacement file Fig. 2 and Fig. 4(b),(d) were amended. The reason is numerical error found, that affected the quantitative estimates of correlation time, but did not affect the main messag

Quantum Monte Carlo calculations of neutron-alpha scattering

We describe a new method to treat low-energy scattering problems in few-nucleon systems, and we apply it to the five-body case of neutron-alpha scattering. The method allows precise calculations of low-lying resonances and their widths. We find that a good three-nucleon interaction is crucial to obtain an accurate description of neutron-alpha scattering.Comment: 4 pages, 2 figures, submitted to Physical Review Letter

The Euro Crisis in the Mirror of the EMS: How Tying Odysseus to the Mast Avoided the Sirens but Led Him to Charybdi

Why was recovery from the euro area crisis delayed for a decade? The explanation lies in the absence of credible and timely policies to backstop financial intermediaries and sovereign debt markets. In this paper we add light and color to this analysis, contrasting recent experience with the 1992-3 crisis in the European Monetary System, when national central banks and treasuries more successfully provided this backstop. In the more recent episode, the incomplete development of the euro area constrained the ability of the ECB and other European institutions to do likewis

The Euro Crisis in the Mirror of the EMS: How Tying Odysseus to the Mast Avoided the Sirens but Led Him to Charybdis

Why was recovery from the euro area crisis delayed for a decade? The explanation lies in the absence of credible and timely policies to backstop financial intermediaries and sovereign debt markets. In this paper we add light and color to this analysis, contrasting recent experience with the 1992-3 crisis in the European Monetary System, when national central banks and treasuries more successfully provided this backstop. In the more recent episode, the incomplete development of the euro area constrained the ability of the ECB and other European institutions to do likewise.Keynes Fund at Cambridge University. The Making of the Euro-Area Crisis: Lessons from Theory and History (JHLP)

Ground-state Wave Function Of Shallow Donors In Uniaxially Stressed Silicon: Piezohyperfine Constants Determined By Electron-nuclear Double Resonance

Stress-induced changes in the ENDOR spectra of a shallow donor electron interacting with various Si29 nuclei neighboring the donor have been experimentally and theoretically investigated. For each of the three measured donors - As, P, and Sb - the compressional, uniaxial stress was applied along the [001] axis and its magnitude corresponded to strains up to 10-3. To describe the observed linear and quadratic shifts and splitting\u27s of the lines in an ENDOR shell, we have defined a set of piezo hyperfine constants. One piezo hyperfine constant was measured for each axis-class shell; three independent piezo hyperfine constants were measured for each shell of the other shell symmetry classes. Piezo hyperfine constants are reported for more than 15 measured lattice shells about each donor. Analysis of the results shows that the constants for any one shell can be attributed primarily to changes in the Fermi contact hyperfine constants at the various lattice sites within that shell. Consequently, the stress-induced changes are directly related to wave-function density changes at specific points in the lattice. Calculations of these wave-function density changes have been performed using a model based on the valley-repopulation effect and on an effect due to the redistribution of the radial envelope function (RREF effect). The calculations and experimental results are qualitatively in good agreement. The quantitative theoretical accuracy is not sufficient to match all the experimental shells to the actual lattice shells, but a new match of shell Q and the (1,1,5) shell has been determined and other matchings are suggested. The theoretical and experimental results provide information on two intrinsic lattice parameters: the deformation-potential constant Ξu, and the location of the conduction-band minimum k0. Difficulties with assigning a value to Ξu because of the RREF effect are discussed. A revised spin-resonance value for Ξu was found to be 10 ± 1 eV. Applying the above model to the previously matched shells [A and (0,0,4), B and (4,4,0), K and (0,0,8)], one finds an average k0=(0.86±0.02)kmax. © 1970 The American Physical Society