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

Non-linear ripple dynamics on amorphous surfaces patterned by ion-beam sputtering

Erosion by ion-beam sputtering (IBS) of amorphous targets at off-normal incidence frequently produces a (nanometric) rippled surface pattern, strongly resembling macroscopic ripples on aeolian sand dunes. Suitable generalization of continuum descriptions of the latter allows us to describe theoretically for the first time the main nonlinear features of ripple dynamics by IBS, namely, wavelength coarsening and non-uniform propagation velocity, that agree with similar results in experiments and discrete models. These properties are seen to be the anisotropic counterparts of in-plane ordering and (interrupted) pattern coarsening in IBS experiments on rotating substrates and at normal incidence.Comment: 5 pages, 3 figure

Symmetry of surface nanopatterns induced by ion-beam sputtering: Role of anisotropic surface diffusion

Ion-beam sputtering (IBS) is a cost-effective technique able to produce ordered nanopatterns on the surfaces of different materials. To date, most theoretical studies of this process have focused on systems which become amorphous under irradiation, e.g., semiconductors at room temperature. Thus, in spite of the large amount of experimental work on metals, or more recently on semiconductors at high temperatures, such experimental contexts have received relatively little theoretical attention. These systems are characterized by transport mechanisms, e.g., surface diffusion, which are anisotropic as a reflection of the crystalline structure not being overruled by the irradiation. Here, we generalize a previous continuum theory of IBS at normal incidence, in order to account for anisotropic surface diffusion. We explore systematically our generalized model in order to understand the role of anisotropy in the space-ordering properties of the resulting patterns.We acknowledge discussions with J.-S. Kim and J.-H. Kim. This work has been funded through MINECO (Spain) Grants No. FIS2012-38866-C05-01, No. FIS2012-32349, No. FIS2013-47949-C2-2, and No. FIS2015-66020-C2-1-P

Nonlinear theory of ion-induced solid flow

[Abstract of]: 25th Conference on Applications of Accelerators in Research and Industry (CAARI 2018), Grapevine, Texas, USA, August 12-17, 2018.Ion beam sputtering (IBS) is a powerful technique employed to induce surface nanopatterns over relatively large areas for a wide range of materials [1]. This approach has many applications in modern technology like magnetic storage, quantum device design or, for example, producing the selective attachment of specific molecules to substrates, with implications in biology and catalysis

Scarcity climate rents under a carbon price with oligopoly competition

Prior research has shown that environmental policy can create scarcity rents. We analyse this phenomenon in the framework of a duopoly that faces a carbon price, considering both Cournot and Stackelberg competition. We identify the different sources of scarcity rents, which we classify in ‘output’ and ‘grandfathering’ scarcity rents. The former depend on the elasticity of the rivals’ output to the carbon price, while the latter is exogenous. We also determine under which conditions these rents can be large enough to increase firms’ profits and, as a policy implication, to what extent the existence of scarcity rents can make the firms agree on a tougher policy. This event is more likely to happen under Cournot than under Stackelberg competition, and the chances increase if the firms are allowed to pollute a large amount without paying a price

Effects of advertising on problem gambling: Neural-cue reactivity as a possible underlying mechanism

Problem gambling has recently been reclassified as a non-substance-associated behavioral addiction. To the associated vital impact (family, social, labor, and economic), we must add its increasing incidence in recent years, which has led to prioritizing the problem from the point of view of public health. Although the effects of advertising on gambling behavior have been explored since the second half of the twentieth century, there is a lack of research regarding its underlying mechanisms. Thus, the objective of this review is to present an update on the effects of advertisements on gambling attitudes and behavioral intentions, as well as to present the neurobiological correlates of gambling-related cues as a possible hypothesis for this effect. Advertisements in various formats may act both as a precipitating factor and as a maintenance factor for the gambling disorder, changing both attitudes and beliefs about gambling. Activation of brain areas related to reward, such as accumbens nucleus, to memory, such as hippocampus or amygdala, and to executive functions could be the underlying mechanism of this effect. Also, ads promoting responsible gambling do not appear to be effective in reducing behavior or encouraging self-control, but the available evidence is scarce. Therefore, the number of studies on this topic needs to increase. In addition, the available evidence questions the effectiveness of responsible gambling policies to promote self-control in this population, as well as to reduce the negative impact of this disorder, so future research on neural-cue reactivity to gambling-related stimuli may serve to improve the design of advertising strategies that increase the impact of these messages

Sufrimiento competitivo y rendimiento en deportes de resistencia

La literatura que trata de relacionar aspectos precompetitivos como la ansiedad o el estado de ánimo con el rendimiento, en deportes de resistencia, es muy extensa. Sin embargo, las medidas precompetitivas han mostrado importantes inconsistencias en los resultados debido a que no tienen en cuenta las fluctuaciones en la respuesta emocional y en los procesos psicológicos del atleta una vez comenzada la competición (Hammersmeister y Burton, 1995). En esta investigación se estudia la relación de aspectos precompetitivos, como la ansiedad, el estado de ánimo y la autoeficacia, y aspectos acaecidos durante la competición, como las percepciones de amenaza y los recursos de afrontamiento,con el rendimiento. Mientras los aspectos precompetitivos se relacionan pobremente con el rendimiento, las percepciones de amenaza y los recursos de afrontamiento tienen un mayor poder explicativo de éste. Los resultados dan validez al concepto de sufrimiento competitivo que aparece cuando el atleta obtiene la certeza, mientras está compitiendo, de que no alcanzará el objetivo por el que está luchando.Research which attempts to relate precompetitive factors like anxiety or mood state with performance in endurance sports is very extensive. However, precompetitive measurements have showed important incongruence in their results because they don't bear in mind the changes in the emotional response and in the psychological processes of the athlete when the competition has begun (Hammersmeister y Burton, 1995). In this research, we study the relationship between precompetitive aspects -like anxiety, mood and self-efficacy-, aspects which arise when the competition has begun - like treath perceptions and coping resources-, and performance. While precompetitive aspects are poorly related with performance, treath perceptions and coping resources have a bigger explicative power over performance. Results give validity to the competitive suffering concept which arises when the athlete discovers, while competing, that he will not reach the goal which he is fighting for

Ansiedad Futura en Adultos Jóvenes Españoles : Propiedades Psicométricas de la Dark Future Scale

Background/Objective:The Dark Future Scale (DFS) is a selfreport instrument which assesses the tendency to think about the future with anxiety, fear, and uncertainty. Although it has been applied in different populations, instrumental studies are scarce, and there is no validated Spanish version. The aim was therefore to develop a Spanish version of the scale (DFS-S) and to analyze its psychometric properties in a sample of young adults. Method:Participants were 1,019 individuals aged from 18 to 24 years. They completed the DFS-S and the IPIP-BFM-20. Validity evidence based on the internal structure, including measurement invariance across gender, as well as on relationships with personality traits was obtained. Reliability and gender differences in DFS-S scores were also examined. Results:Results supported a single-factor structure, χ2(5) = 10.79, CFI = .999, RMSEA = .034, SRMR = .016, that was invariant across gender. Reliability of test scores was satisfactory (ω= .92). In the correlation analysis, future anxiety showed a strong positive correlation with neuroticism (.42) and a moderate negative correlation with extraversion (-.25). Females scored higher than males on future anxiety. Conclusions:The DFS-S has sat-isfactory psychometric properties and it is an adequate tool for measuring future anxiety among young adults.Antecedentes/Objetivo: La Dark Future Scale (DFS) evalúa la tendencia a pensar en el futuro con ansiedad, miedo e incertidumbre. Aunque ha sido usada en diferentes poblaciones, los estudios instrumentales son es-casos y no hay una versión adaptada al español. El objetivo del estudio fue adaptarla al español (DFS-S) y analizar sus propiedades psicométricas en una muestra de adultos jóvenes. Método: Participaron 1.019 jóvenes entre 18 y 24 años. Completaron la DFS-S y el IPIP-BFM-20. Se analizan evidencias de validez basadas en la estructura interna, incluyendo la invarianza de medida según el género, y basadas en las relaciones con rasgos de personalidad, así como análisis de la fiabilidad y de las diferencias de género. Resultados: Los resultados apoyaron una estructura de un solo factor, χ2(5) = 10.79, CFI = .999, RMSEA = .034, SRMR = .016, con invarianza respecto al género, y con coeficiente de fiabilidad satisfactorio (ω= .92). Se encontró correlación positiva fuerte entre ansiedad futura y neuroticismo (.42) y una correlación negativa moderada con extraversión (-.25). Las puntuaciones en ansiedad futura fueron mayores en las mujeres. Conclusiones: Los resultados muestran propiedades psicométricas satisfactorias de la DFS-S, siendo un instrumento adecuado para medir la ansiedad futura en adultos jóvenes