A comparison of turbulence measurement methods

An experiment is described in which temperature (density) and velocity are measured separately but simultaneously as functions of time so that it is possible to determine the relationships among velocity, density, and the product of density and velocity. Temperatures were measured with a dual-wire thermocouple probe. Velocity data were supplied by a fringe laser-Doppler anemometer. Signals from thermocouples and the laser were recorded on FM magnetic tape for later processing

The Babitsky Trial: Rule of Law?

Bonaparte Louis-Napoléon, Rouland Gustave. Reconnaissance de la Société philotechnique. In: Bulletin administratif de l'instruction publique. Tome 12 n°137, mai 1861. pp. 70-71

Subspace subcodes of Reed-Solomon codes

We introduce a class of nonlinear cyclic error-correcting codes, which we call subspace subcodes of Reed-Solomon (SSRS) codes. An SSRS code is a subset of a parent Reed-Solomon (RS) code consisting of the RS codewords whose components all lie in a fixed ν-dimensional vector subspace S of GF (2m). SSRS codes are constructed using properties of the Galois field GF(2m). They are not linear over the field GF(2ν), which does not come into play, but rather are Abelian group codes over S. However, they are linear over GF(2), and the symbol-wise cyclic shift of any codeword is also a codeword. Our main result is an explicit but complicated formula for the dimension of an SSRS code. It implies a simple lower bound, which gives the true value of the dimension for most, though not all, subspaces. We also prove several important duality properties. We present some numerical examples, which show, among other things, that (1) SSRS codes can have a higher dimension than comparable subfield subcodes of RS codes, so that even if GF(2ν) is a subfield of GF(2m), it may not be the best ν-dimensional subspace for constructing SSRS codes; and (2) many high-rate SSRS codes have a larger dimension than any previously known code with the same values of n, d, and q, including algebraic-geometry codes. These examples suggest that high-rate SSRS codes are promising candidates to replace Reed-Solomon codes in high-performance transmission and storage systems

The Portability of New Immigrants' Human Capital: Language, Education and Occupational Matching

The implications of human capital portability – including interactions between education, language skills and pre- and post-immigration occupational matching – for earnings are explored for new immigrants to Canada. Given the importance of occupation-specific skills, as a precursor we also investigate occupational mobility and observe convergence toward the occupational skill distribution of the domestic population, although four years after landing immigrants remain less likely have a high skilled job. Immigrants who are able to match their source and host country occupations obtain higher earnings. However, surprisingly, neither matching nor language skills have any impact on the return to pre-immigration work experience, which is observed to be statistically significantly negative. Crucially, English language skills are found to have an appreciable direct impact on earnings, and to mediate the return to pre-immigration education but not labour market experience.immigration, human capital portability, occupation, language, education

The Economic Return on New Immigrants' Human Capital: the Impact of Occupational Matching

Using a data set that provides information on source country employment, we examine the effect of source and host country occupational matching on earnings and the economic rate of return to the foreign human capital of immigrants in Canada. Examining occupational distributions we find that immigrants converge very quickly to the skill distribution of the Canadian population in terms of the main job worked, although four years after landing they are still below the source country distribution. We also find that for a large proportion of immigrants, their intended occupation differs from their source country occupation. Although immigrants who are able to match their source and host country occupations obtain higher earnings, successful occupational matching does not have any impact on the return to foreign potential work experience. However, immigrants who match their source and host country occupations do have a higher return to schooling, particularly for females.Immigrants, Occupational Matching, Human Capital, Canada

Optical Random Riemann Waves in Integrable Turbulence

We examine integrable turbulence (IT) in the framework of the defocusing cubic one-dimensional nonlinear Schr\"{o}dinger equation. This is done theoretically and experimentally, by realizing an optical fiber experiment in which the defocusing Kerr nonlinearity strongly dominates linear dispersive effects. Using a dispersive-hydrodynamic approach, we show that the development of IT can be divided into two distinct stages, the initial, pre-breaking stage being described by a system of interacting random Riemann waves. We explain the low-tailed statistics of the wave intensity in IT and show that the Riemann invariants of the asymptotic nonlinear geometric optics system represent the observable quantities that provide new insight into statistical features of the initial stage of the IT development by exhibiting stationary probability density functions

The Portability of New Immigrants' Human Capital: Language, Education and Occupational Matching

The implications of human capital portability -- including interactions between education, language skills and pre- and post-immigration occupational matching -- for earnings are explored for new immigrants to Canada. Given the importance of occupation-specific skills, as a precursor we also investigate occupational mobility and observe convergence toward the occupational skill distribution of the domestic population, although four years after landing immigrants remain less likely have a high skilled job. Immigrants who are able to match their source and host country occupations obtain higher earnings. However, surprisingly, neither matching nor language skills have any impact on the return to pre-immigration work experience, which is observed to be statistically significantly negative. Crucially, English language skills are found to have an appreciable direct impact on earnings, and to mediate the return to pre-immigration education but not labour market experience.Immigration, human capital portability, occupation, education, language