Editorial for special issue: Advances in sedentary behavior research and translation

Sedentary behaviour—essentially low energy sitting time in waking hours—has emerged as an important topic in public health over the past decade or so. Although Morris and colleagues [1] analysed health outcomes of active versus seated occupations over 60 years ago, it was not until studies of TV viewing in children in the 1980s [2] that researchers started to recognise “too much sitting” as a potentially important health behaviour. Even then the rapid rise in the study of sedentary behaviour was not so evident until the early 2000s [3]–[5]. Studies on screen viewing (TV and computers), sitting at work and school, and sitting in cars have all emerged over this period, as well as a general recognition that high levels of sitting may have detrimental effects on health, and possibly be independent of levels of moderate-to-vigorous physical activity (MVPA). In the past 10–15 years there has been an exponential increase in papers addressing sedentary behaviour from the perspective of sitting, noting that many exercise physiologists still use the word 'sedentary' incorrectly by referring to those not meeting a criterion level of “sufficient” physical activity

Cycles of Wage Discrimination

Using CPS data from 1979-2009 we examine how cyclical downturns and industry-specific demand shocks affect wage differentials between white non-Hispanic males and women, Hispanics and African-Americans. Women's and Hispanics' relative earnings are harmed by negative shocks, while the earnings disadvantage of African-Americans may drop with negative shocks. Negative shocks also appear to increase the earnings disadvantage of bad-looking workers. A theory of job search suggests two opposite-signed mechanisms that affect these wage differentials. It suggests greater absolute effects among job-movers, which is verified using the longitudinal component of the CPS.women, minorities, beauty, search models

Beauty, Productivity and Discrimination: Lawyers' Looks and Lucre

We propose several models in which an ascriptive characteristic generates earnings differentials and is sorted across sectors. The general approach shows how to distinguish the ultimate sources of labor-market returns to such characteristics; the specific example uses longitudinal data on a large sample of attorneys who graduated from one law school. Beauty is measured by ratings of their matriculation photographs. 1) Better-looking attorneys who graduated in the 1970s earned more after 5 years of practice than their worse- looking classmates, other things equal, an effect that grew even larger by the fifteenth year of practice. There is no impact of beauty on earnings among 1980s graduates. 2) Attorneys in the private sector are better-looking than those in the public sector, with the differences rising as workers sort across sector based on their beauty. 3) Male attorneys' probability of attaining an early partnership rises with beauty. The results support a theory of dynamic sorting and the role of customer behavior. We cannot determine whether this is because clients discriminate or because better-looking lawyers are able to obtain greater pecuniary gains for their clients.

Beauty and the Labor Market

We develop a theory of sorting across occupations based on looks and derive its implications for testing for the source of earnings differentials related to looks. These differentials are examined using the 1977 Quality of Employment, the 1971 Quality of American Life, and the 1981 Canadian Quality of Life surveys, all of which contain interviewers' ratings of the respondents' physical appearance. Holding constant demographic and labor-market characteristics, plain people earn less than people of average looks, who earn less than the good-looking. The penalty for plainness is 5 to 10 percent, slightly larger than the premium for beauty. The effects are slightly larger for men than women; but unattractive women are less likely than others to participate in the labor force and are more likely to be married to men with unexpectedly low human capital. Better-looking people sort into occupations where beauty is likely to be more productive; but the impact of individuals' looks on their earnings is mostly independent of occupation.

Localization in one-dimensional incommensurate lattices beyond the Aubry-Andr\'e model

Localization properties of particles in one-dimensional incommensurate lattices without interaction are investigated with models beyond the tight-binding Aubry-Andr\'e (AA) model. Based on a tight-binding t_1 - t_2 model with finite next-nearest-neighbor hopping t_2, we find the localization properties qualitatively different from those of the AA model, signaled by the appearance of mobility edges. We then further go beyond the tight-binding assumption and directly study the system based on the more fundamental single-particle Schr\"odinger equation. With this approach, we also observe the presence of mobility edges and localization properties dependent on incommensuration.Comment: 5 pages, 6 figure

Localization in one dimensional lattices with non-nearest-neighbor hopping: Generalized Anderson and Aubry-Andr\'e models

We study the quantum localization phenomena of noninteracting particles in one-dimensional lattices based on tight-binding models with various forms of hopping terms beyond the nearest neighbor, which are generalizations of the famous Aubry-Andr\'e and noninteracting Anderson model. For the case with deterministic disordered potential induced by a secondary incommensurate lattice (i.e. the Aubry-Andr\'e model), we identify a class of self dual models, for which the boundary between localized and extended eigenstates are determined analytically by employing a generalized Aubry-Andr\'e transformation. We also numerically investigate the localization properties of non-dual models with next-nearest-neighbor hopping, Gaussian, and power-law decay hopping terms. We find that even for these non-dual models, the numerically obtained mobility edges can be well approximated by the analytically obtained condition for localization transition in the self dual models, as long as the decay of the hopping rate with respect to distance is sufficiently fast. For the disordered potential with genuinely random character, we examine scenarios with next-nearest-neighbor hopping, exponential, Gaussian, and power-law decay hopping terms numerically. We find that the higher order hopping terms can remove the symmetry in the localization length about the energy band center compared to the Anderson model. Furthermore, our results demonstrate that for the power-law decay case, there exists a critical exponent below which mobility edges can be found. Our theoretical results could, in principle, be directly tested in shallow atomic optical lattice systems enabling non-nearest-neighbor hopping.Comment: 18 pages, 24 figures updated with additional reference