Are Efficiency Wages Efficient?

Efficiency wage models have been criticized because worker malfeasance can be prevented in a pareto efficient manner by requiring workers to post a bond which they lose if they are caught cheating. However, since it is costly to monitor workers and costless to demand a larger bond, firms should pay nothing for monitoring and demand very large bonds. Since we observe that firms devote considerable resources to monitoring workers, bonds must be limited. Therefore firms must use second best alternatives -- intensive monitoring and/or efficiency wages. The payment of efficiency wages cannot be ruled out on a priori theoretical grounds.

Balloon tank skin strain measurements at liquid-hydrogen temperature on centaur flight vehicle

Balloon tank skin strain measurements at liquid hydrogen temperature on Centaur flight vehicl

Twenty years of the WTO Appellate Body’s “fragmentation jurisprudence”

The World Trade Organisation’s new dispute settlement machinery was one of a number of new international courts and tribunals established during the long decade between the end of the Cold War and the beginning of the new millennium. For international lawyers – long accustomed to life on the margins – the proliferation of new and vibrant specialised regimes of international law was both energising and anxiety producing. At the heart of the anxiety, as Koskenniemi and Leino have described,1 was a concern about the incoherence of international law, famously leading at the end of the 1990s to a debate amongst international lawyers about the dangers of the growing normative incoherence of the system. What would happened when two international tribunals sought to apply inconsistent rules to the same dispute? Could one tribunal legitimately consider rules of law which fell outside its specialised mandate, so as to reduce the chance of conflict? Given its position as one of the most significant, and certainly the most active, of this new generation of international tribunals, the WTO’s Appellate Body has been closely scrutinised for the approach it has taken in cases which appear to raise questions about the relationship between WTO law and so-called ‘non-WTO law’, and a range of views have emerged within WTO scholarship about what the appropriate role that the WTO should play in this respect. This contribution reflects on the first 20 years of the Appellate Body’s jurisprudence, specifically as it relates to questions of normative fragmentation. The first section provides an overview of some of the highlights of the WTO’s jurisprudence in this regard, focussing in particular on the often-discussed issue of the use which has been made of general public international law in the context of WTO dispute settlement. The second section then suggests that the primary driver of the Appellate Body’s approach so far has not been the institutional myopia and normative closure of which they are sometimes accused, but rather a judicial sensibility which valorises the virtues of modesty, caution and self-restraint. In the third section, I offer a related argument, having to do with the causes of fragmentation. It is typically said that the problem of fragmentation arises from the specialised mandates of many international legal regimes, and the lack of institutionalised coordination between them. I note, however, that in fact the mandates, boundaries and specialisms of these regimes are not fixed in advance, but are in part the product of ongoing boundary work – and that the ‘fragmentation’ jurisprudence of the Appellate Body has predictably involved boundary work of a particularly intense kind

Cleaning the USNO-B Catalog through automatic detection of optical artifacts

The USNO-B Catalog contains spurious entries that are caused by diffraction spikes and circular reflection halos around bright stars in the original imaging data. These spurious entries appear in the Catalog as if they were real stars; they are confusing for some scientific tasks. The spurious entries can be identified by simple computer vision techniques because they produce repeatable patterns on the sky. Some techniques employed here are variants of the Hough transform, one of which is sensitive to (two-dimensional) overdensities of faint stars in thin right-angle cross patterns centered on bright (<13 \mag) stars, and one of which is sensitive to thin annular overdensities centered on very bright (<7 \mag) stars. After enforcing conservative statistical requirements on spurious-entry identifications, we find that of the 1,042,618,261 entries in the USNO-B Catalog, 24,148,382 of them (2.3 \percent) are identified as spurious by diffraction-spike criteria and 196,133 (0.02 \percent) are identified as spurious by reflection-halo criteria. The spurious entries are often detected in more than 2 bands and are not overwhelmingly outliers in any photometric properties; they therefore cannot be rejected easily on other grounds, i.e., without the use of computer vision techniques. We demonstrate our method, and return to the community in electronic form a table of spurious entries in the Catalog.Comment: published in A

Quantum phase transitions in the Kane-Mele-Hubbard model

We study the two-dimensional Kane-Mele-Hubbard model at half filling by means of quantum Monte Carlo simulations. We present a refined phase boundary for the quantum spin liquid. The topological insulator at finite Hubbard interaction strength is adiabatically connected to the groundstate of the Kane-Mele model. In the presence of spin-orbit coupling, magnetic order at large Hubbard U is restricted to the transverse direction. The transition from the topological band insulator to the antiferromagnetic Mott insulator is in the universality class of the three-dimensional XY model. The numerical data suggest that the spin liquid to topological insulator and spin liquid to Mott insulator transitions are both continuous.Comment: 13 pages, 10 figures; final version; new Figs. 4(b) and 8(b

Precision CW laser automatic tracking system investigated

Precision laser tracker capable of tracking a low acceleration target to an accuracy of about 20 microradians rms is being constructed and tested. This laser tracking has the advantage of discriminating against other optical sources and the capability of simultaneously measuring range

Effect of the Spatial Dispersion on the Shape of a Light Pulse in a Quantum Well

Reflectance, transmittance and absorbance of a symmetric light pulse, the carrying frequency of which is close to the frequency of interband transitions in a quantum well, are calculated. Energy levels of the quantum well are assumed discrete, and two closely located excited levels are taken into account. A wide quantum well (the width of which is comparable to the length of the light wave, corresponding to the pulse carrying frequency) is considered, and the dependance of the interband matrix element of the momentum operator on the light wave vector is taken into account. Refractive indices of barriers and quantum well are assumed equal each other. The problem is solved for an arbitrary ratio of radiative and nonradiative lifetimes of electronic excitations. It is shown that the spatial dispersion essentially affects the shapes of reflected and transmitted pulses. The largest changes occur when the radiative broadening is close to the difference of frequencies of interband transitions taken into account.Comment: 7 pages, 5 figure

Diffusion in simple fluids

Computed self diffusion coefficients for the Lennard-Jones and hard sphere fluids are related by Dej = DNs(aB) exp (--e/2kB T) where σB=σLJ(2/[1+ii(1+2kBT/ε)])1/6, the effective hard sphere diameter, is the (average) distance of closest approach in collisions between molecules which interact with the positive part of the LJ potential, and the Arrhenius term reflects the influence of the negative part. σLJ and ε are the size and well depth parameters. Measured diffusion coefficients of the halomethane liquids are reproduced by the equation over wide ranges of temperature and density and do not reveal any influence of the inelastic effects associated with molecular anisotropy