23,300 research outputs found
Incentives in Religious Performance: a Stochastic Dominance Approach
Using a stochastic dominance approach in an international dataset of about 10,000 Catholic subjects, we show that incentives (based on absolute belief) play a crucial role in religious practice (church attendance and prayer). Furthermore, we find that when both positive (heaven) and negative (hell) incentives are available, the former have a much stronger effect than the latter. The results are confirmed using Kolmogorov-Smirnov tests.Incentives, rewards, punishment, Economics of Religion
Aerodynamic Optimization of High-Speed Trains Nose using a Genetic Algorithm and Artificial Neural Network
An aerodynamic optimization of the train aerodynamic characteristics in term of front wind action sensitivity is carried out in this paper. In particular, a genetic algorithm (GA) is used to perform a shape optimization study of a high-speed train nose. The nose is parametrically defined via BĂ©zier Curves, including a wider range of geometries in the design space as possible optimal solutions. Using a GA, the main disadvantage to deal with is the large number of evaluations need before finding such optimal. Here it is proposed the use of metamodels to replace Navier-Stokes solver. Among all the posibilities, Rsponse Surface Models and Artificial Neural Networks (ANN) are considered. Best results of prediction and generalization are obtained with ANN and those are applied in GA code. The paper shows the feasibility of using GA in combination with ANN for this problem, and solutions achieved are included
The June 2012 transit of Venus. Framework for interpretation of observations
Ground based observers have on 5/6th June 2012 the last opportunity of the
century to watch the passage of Venus across the solar disk from Earth. Venus
transits have traditionally provided unique insight into the Venus atmosphere
through the refraction halo that appears at the planet outer terminator near
ingress/egress. Much more recently, Venus transits have attracted renewed
interest because the technique of transits is being successfully applied to the
characterization of extrasolar planet atmospheres. The current work
investigates theoretically the interaction of sunlight and the Venus atmosphere
through the full range of transit phases, as observed from Earth and from a
remote distance. Our model predictions quantify the relevant atmospheric
phenomena, thereby assisting the observers of the event in the interpretation
of measurements and the extrapolation to the exoplanet case. Our approach
relies on the numerical integration of the radiative transfer equation, and
includes refraction, multiple scattering, atmospheric extinction and solar limb
darkening, as well as an up to date description of the Venus atmosphere. We
produce synthetic images of the planet terminator during ingress/egress that
demonstrate the evolving shape, brightness and chromaticity of the halo.
Guidelines are offered for the investigation of the planet upper haze from
vertically-unresolved photometric measurements. In this respect, the comparison
with measurements from the 2004 transit appears encouraging. We also show
integrated lightcurves of the Venus/Sun system at various phases during transit
and calculate the respective Venus-Sun integrated transmission spectra. The
comparison of the model predictions to those for a Venus-like planet free of
haze and clouds (and therefore a closer terrestrial analogue) complements the
discussion and sets the conclusions into a broader perspective.Comment: 14 pages; 14 figures; Submitted on 02/06/2012; A&A, accepted for
publication on 30/08/201
Characterization and evolution of the sediments of a Mediterranean coastal lagoon located next to a former mining area
Coastal lagoons are ecosystems that are relatively enclosed water bodies under the influence of both the terrestrial and themarine environment, being vulnerable to human impacts. Human activities, such asmining extraction, are significant anthropogenic coastal stressors that can negatively affect ecosystems and communities. In light of the above, the objective of this research is to examine the influence ofmetal mining activities on the composition of sediments of a Mediterranean coastal lagoon, named Mar Menor. This paper presents a comprehensive characterization for grain size, mineralogy, geochemistry and organic matter of sediments of this coastal lagoon, investigating their variation along space and time. Sedimentation dynamics are ruling clearly the grain size predominant in each area of the MarMenor coastal lagoon, determining the existence of entrainment, transport and sedimentation areas. Forminerals, elements and organic matter, sedimentation dynamics are also determining their distribution.The authors would like to thank Fundación Séneca for funding the project 12038/PI/09. In addition, they want to acknowledge the cooperation of J.M. Peñas, R. Baños, J. Saura, M. Saura and B. Villaescusa who helped us to improve this research and to Mr. and Mrs. Purves for their English grammar supervision
Ion induced solid flow
Amorphous solids can flow over very long periods of time. Solid flow can also
be artificially enhanced by creating defects, as by Ion Beam Sputtering (IBS)
in which collimated ions with energies in the 0.1 to 10 keV range impact a
solid target, eroding its surface and inducing formation of nanometric
structures. Recent experiments have challenged knowledge accumulated during the
last two decades so that a basic understanding of self-organized nano-pattern
formation under IBS is still lacking. We show that considering the irradiated
solid to flow like a highly viscous liquids can account for the complex IBS
morphological phase diagram, relegating erosion to a subsidiary role and
demonstrating a controllable instance of solid flow at the nanoscale. This new
perspective can allow for a full harnessing of this bottom-up route to
nanostructuring.Comment: 17 pages, 5 figure
Temporary help agencies and occupational mobility
This paper focuses upon the effect of Temporary Help Agencies (THAs) on occupational mobility through a comparison of the job-to-job upgrading chances of THA and non-THA workers. A screening approach to the role of these labor "brokers" suggests that agency workers can expect greater upgrading chances between two different occupations. Results obtained from a sample of Spanish workers show that working through these intermediaries allows workers in intermediate occupational levels to avoid occupational demotions more easily than non-THA ones. Moreover, THAs improve the probability for high-skilled workers of achieving a permanent contract. The empirical analysis demonstrates that the existence of self-selection is an important explanation for increased occupational mobility among THA workers in Spain
The nineties in Spain: too much flexibility in the youth labour market?
This paper examines movements into and out of employment in the Spanish youth labour market throughout the nineties. We analyze how differences in personal and economic circumstances influence such movements. In addition, we consider the importance of duration dependence in determining them. Our main findings are that: (i) Very young workers, women and those with lower qualification levels are more likely to be affected by high labour turnover; (ii) The existence of unobserved heterogeneity has important consequences in the unemployment hazard rate; (iii) In the 90's, employment hazard rates were substantially affected by the extensive use of fixed-term contracts, although the 1997 labour market reform seems to have reduced this hazard rate; (iv) The intervention of temporary help agencies has a positive impact on the likelihood of leaving unemployment, although only for short-term unemployed individuals; at the same time, however, the employment hazard rate is substantially higher within these agencies
Short-range stationary patterns and long-range disorder in an evolution equation for one-dimensional interfaces
A novel local evolution equation for one-dimensional interfaces is derived in
the context of erosion by ion beam sputtering. We present numerical simulations
of this equation which show interrupted coarsening in which an ordered cell
pattern develops with constant wavelength and amplitude at intermediate
distances, while the profile is disordered and rough at larger distances.
Moreover, for a wide range of parameters the lateral extent of ordered domains
ranges up to tens of cells. This behavior is new in the context of dynamics of
surfaces or interfaces with morphological instabilities. We also provide
analytical estimates for the stationary pattern wavelength and mean growth
velocity
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