Immigration, wages, and compositional amenities

Economists are often puzzled by the stronger public opposition to immigration than trade, since the two policies have symmetric effects on wages. Unlike trade, however, immigration changes the composition of the local population, imposing potential externalities on natives. While previous studies have focused on fiscal spillovers, a broader class of externalities arise because people value the ‘compositional amenities’ associated with the characteristics of their neighbors and co-workers. In this paper we present a new method for quantifying the relative importance of these amenities in shaping attitudes toward immigration. We use data for 21 countries in the 2002 European Social Survey, which included a series of questions on the economic and social impacts of immigration, as well as on the desirability of increasing or reducing immigrant inflows. We find that individual attitudes toward immigration policy reflect a combination of concerns over conventional economic impacts (i.e., on wages and taxes) and compositional amenities, with substantially more weight on composition effects. Most of the difference in attitudes to immigration between more and less educated natives is attributable to heightened concerns over compositional amenities among the less-educated

Understanding Attitudes to Immigration: The Migration and Minority Module of the first European Social Survey

Immigration control is an issue that figures prominently in public policy discussions and election campaigns throughout Europe. Although immigration may have positive effects on economic efficiency and growth in the receiving economy, it is often the negative aspects -or perceived negative aspects - of immigration that attract the most attention. In this paper, we use the immigration module of the European Social Survey (ESS), which we developed in collaboration with the ESS survey team, to investigate public opinions about immigration, and the various dimensions of economic, public and private life that individuals feel are affected by immigration. We show that there is substantial variation in the strength of anti)immigrant opinion across European countries, and that attitudes toward immigration also vary systematically with characteristics such as age, education, and urban/rural location. We propose possible interpretations of some of these regularities

The effect of spatial, spectral and radiometric factors on classification accuracy using thematic mapper data

An experiment of a factorial design was conducted to test the effects on classification accuracy of land cover types due to the improved spatial, spectral and radiometric characteristics of the Thematic Mapper (TM) in comparison to the Multispectral Scanner (MSS). High altitude aircraft scanner data from the Airborne Thematic Mapper instrument was acquired over central California in August, 1983 and used to simulate Thematic Mapper data as well as all combinations of the three characteristics for eight data sets in all. Results for the training sites (field center pixels) showed better classification accuracies for MSS spatial resolution, TM spectral bands and TM radiometry in order of importance

Method of identifying clusters representing statistical dependencies in multivariate data

Approach is first to cluster and then to compute spatial boundaries for resulting clusters. Next step is to compute, from set of Monte Carlo samples obtained from scrambled data, estimates of probabilities of obtaining at least as many points within boundaries as were actually observed in original data

Dynamics of leg muscle function in tammar wallabies (M. eugenii) during level versus incline hopping

The goal of our study was to examine whether the in vivo force-length behavior, work and elastic energy savings of distal muscle-tendon units in the legs of tammar wallabies (Macropus eugenii) change during level versus incline hopping. To address this question, we obtained measurements of muscle activation (via electromyography), fascicle strain (via sonomicrometry) and muscle-tendon force (via tendon buckles) from the lateral gastrocnemius (LG) and plantaris (PL) muscles of tammar wallabies trained to hop on a level and an inclined (10°, 17.4% grade) treadmill at two speeds (3.3 m s^(-1) and 4.2 m s^(-1)). Similar patterns of muscle activation, force and fascicle strain were observed under both level and incline conditions. This also corresponded to similar patterns of limb timing and movement (duty factor, limb contact time and hopping frequency). During both level and incline hopping, the LG and PL exhibited patterns of fascicle stretch and shortening that yielded low levels of net fascicle strain [LG: level, -1.0±4.6% (mean ± s.e.m.) vs incline, 0.6±4.5%; PL: level, 0.1±1.0% vs incline, 0.4±1.6%] and muscle work (LG: level, -8.4±8.4 J kg^(-1) muscle vs incline, -6.8±7.5 J kg^(-1) muscle; PL: level, -2.0±0.6 J kg^(-1) muscle vs incline, -1.4±0.7 J kg^(-1) muscle). Consequently, neither muscle significantly altered its contractile dynamics to do more work during incline hopping. Whereas electromyographic (EMG) phase, duration and intensity did not differ for the LG, the PL exhibited shorter but more intense periods of activation, together with reduced EMG phase (P<0.01), during incline versus level hopping. Our results indicate that design for spring-like tendon energy savings and economical muscle force generation is key for these two distal muscle-tendon units of the tammar wallaby, and the need to accommodate changes in work associated with level versus incline locomotion is achieved by more proximal muscles of the limb

Self-organized escape of oscillator chains in nonlinear potentials

We present the noise free escape of a chain of linearly interacting units from a metastable state over a cubic on-site potential barrier. The underlying dynamics is conservative and purely deterministic. The mutual interplay between nonlinearity and harmonic interactions causes an initially uniform lattice state to become unstable, leading to an energy redistribution with strong localization. As a result a spontaneously emerging localized mode grows into a critical nucleus. By surpassing this transition state, the nonlinear chain manages a self-organized, deterministic barrier crossing. Most strikingly, these noise-free, collective nonlinear escape events proceed generally by far faster than transitions assisted by thermal noise when the ratio between the average energy supplied per unit in the chain and the potential barrier energy assumes small values

Assessment of Thematic Mapper band-to-band registration by the block correlation method

Rectangular blocks of pixels from one band image were statistically correlated against blocks centered on identical pixels from a second band image. The block pairs were shifted in pixel increments both vertically and horizontally with respect to each other and the correlation coefficient to the maximum correlation was taken as the best estimate of registration error for each block pair. For the band combinations of the Arkansas scene studied, the misregistration of TM spectral bands within the noncooled focal plane lie well within the 0.2 pixel target specification. Misregistration between the middle IR bands is well within this specification also. The thermal IR band has an apparent misregistration with TM band 7 of approximately 3 pixels in each direction. The TM band 3 has a misregistration of approximately 0.2 pixel in the across-scan direction and 0.5 pixel in the along-scan direction, with both TM bands 5 and 7

Thematic Mapper image quality: Preliminary results

Based on images analyzed so far, the band to band registration accuracy of the thematic mapper is very good. For bands within the same focal plane, the mean misregistrations are well within the specification, 0.2 pixels. For bands between the cooled and uncooled focal planes, there is a consistent mean misregistration of 0.5 pixels along-scan and 0.2-0.3 pixels across-scan. It exceeds the permitted 0.3 pixels for registration of bands between focal planes. If the mean misregistrations were removed by the data processing software, an analysis of the standard deviation of the misregistration indicates all band combinations would meet the registration specifications except for those including the thermal band. Analysis of the periodic noise in one image indicates a noise component in band 1 with a spatial frequency equivalent to 3.2 pixels in the along-scan direction

Did the Elimination of Mandatory Retirement Affect Faculty Retirement Flows?

A special exemption from the 1986 Age Discrimination Act allowed colleges and universities to enforce mandatory retirement of faculty at age 70 until 1994. We compare faculty turnover rates at a large sample of institutions before and after the federal law change, and at a set of institutions that were covered by earlier state laws prohibiting compulsory retirement. Retirement rates at institutions that enforced mandatory retirement exhibited sharp ?spikes? at ages 70 and 71. About 90 percent of professors who were still teaching at age 70 retired within two years. After the elimination of compulsory retirement the retirement rates of 70 and 71-year-olds fell to levels comparable to 69- year-olds, and over one-half of 70-year-olds were still teaching two years later. These findings indicate that U.S. colleges and universities will experience a rise in the number of older faculty over the coming years. The increase is likely to be larger at private research universities, where a higher fraction of faculty has traditionally remained at work until age 70

The Discovery of XY Sex Chromosomes in a \u3cem\u3eBoa\u3c/em\u3e and \u3cem\u3ePython\u3c/em\u3e

For over 50 years, biologists have accepted that all extant snakes share the same ZW sex chromosomes derived from a common ancestor [1, 2, 3], with different species exhibiting sex chromosomes at varying stages of differentiation. Accordingly, snakes have been a well-studied model for sex chromosome evolution in animals [1, 4]. A review of the literature, however, reveals no compelling support that boas and pythons possess ZW sex chromosomes [2, 5]. Furthermore, phylogenetic patterns of facultative parthenogenesis in snakes and a sex-linked color mutation in the ball python (Python regius) are best explained by boas and pythons possessing an XY sex chromosome system [6, 7]. Here we demonstrate that a boa (Boa imperator) and python (Python bivittatus) indeed possess XY sex chromosomes, based on the discovery of male-specific genetic markers in both species. We use these markers, along with transcriptomic and genomic data, to identify distinct sex chromosomes in boas and pythons, demonstrating that XY systems evolved independently in each lineage. This discovery highlights the dynamic evolution of vertebrate sex chromosomes and further enhances the value of snakes as a model for studying sex chromosome evolution