The electrochemical stability of thiols on gold surfaces

In this paper we present a comparative analysis of the electrochemical stability of alkanethiols, aromatic and heterocyclic thiols on the Au(111) and Au(100) faces in relation to the theoretical energetic data. The peak potential and surface coverage are used as the key parameters to estimate the electrochemical stability while work function changes, adsorption energies and surface free energies calculated from periodic DFT, including van der Waals interactions, are used for the theoretical estimation. We find that the peak potentials do not correlate with work function changes and adsorption energies in particular for aromatic and heterocyclic thiols. In contrast, the reductive desorption potentials for the different thiols show a good correlation with the surface free energy of the SAMs estimated by density functional theory calculations. Surface coverage is a key factor that controls reductive desorption through van der Waals interactions.Fil: Salvarezza, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Carro, Pilar. Universidad de La Laguna; Españ

A simple approach to distributed objects in prolog

We present the design of a distributed object system for Prolog, based on adding remote execution and distribution capabilities to a previously existing object system. Remote execution brings RPC into a Prolog system, and its semantics is easy to express in terms of well-known Prolog builtins. The final distributed object design features state mobility and user-transparent network behavior. We sketch an implementation which provides distributed garbage collection and some degree of tolerance to network failures. We provide a preliminary study of the overhead of the communication mechanism for some test cases

Movers or Stayers? Heterogeneity of Older Adults' Residential Profiles Across Continental Europe

Traditionally, the emotional attachment older adults have to their homes and the economic and health burden caused by residential moves have had a deterrent effect on mobility during old age. In spite of this static general trend, 20% of older Europeans change their residential location after the age of 65. Some studies point out that this percentage will increase in the coming decades along with the onset of baby-boom cohorts reaching older ages. The main objective of this article is to describe the residential mobility trends during old age in some European countries and identify the main features of those elderly that move after 65, using data from the Survey of Health, Ageing and Retirement in Europe (SHARE)

How do you celebrate the dead?

This article was originally published in The Prophet -- a journal created by and for the students at the Boston University School of Theology (BUSTH) to amplify the voices of STH students by promoting and sharing a range of perspectives on matters of concern including, but not limited to, spiritual practices, faith communities and society, the nature of theology, and current affairs. It serves as a platform for STH students to share their academic work, theological reflections, and life experiences with one another and the wider community

A pied-piper situation : do bureaucratic researchers produce more science?

¿Puede un científico confiar en que el gobierno le va a pagar honestamente? En la relación entre la ciencia y el Estado, el gobernante sale ganando si no paga (o si no paga honradamente). Todo científico público, así, afronta el riesgo de que tras una carrera larga y difícil el gobernante cambie las reglas del juego. A pesar de que la solución a este problema de credibilidad es lo que da forma a las instituciones de la ciencia pública el problema ha sido rara vez estudiado teórica o empíricamente en los estudios de la ciencia. En este trabajo proponemos un modelo de esa relación entre gobiernos y científicos de acuerdo con la teoría de juegos que muestra la importancia del tipo de contrato que los vincula, el que sea más o menos burocrático en un sentido weberiano. Hasta cierto punto, los contratos burocráticos —como los de los funcionarios— protegen a los científicos contra el mal comportamiento de los gobernantes. Mediante esas reglas burocráticas, los contratos atan las manos del gobierno con lo que se hace creíble su compromiso a la vez que se protege el delicado sistema de recompensas de la ciencia. De esta manera se estimula la productividad tanto en calidad como en cantidad. Sin embargo, cuando se da el caso de gobiernos fiables los contratos burocráticos limitan los sistemas de incentivos y van en contra tanto de la receptividad de los científicos a las demandas de los gobiernos o de la sociedad como, al final, al interés de los gobiernos por el producto que ofrecen. En este trabajo utilizamos evidencia comparada entre países que confirma las proposiciones del modelo teórico y muestra cómo los contratos burocráticos estimulan la productividad científica en el caso de gobiernos poco confiables —como en el caso de las dictaduras— pero limitan esa productividad con gobiernos más fiables — como las democracias—

Political Regimes, Bureaucracy, and Scientific Productivity

Can a scientist trust that the government is going to pay him or her fairly? In the science–government relationship, an incumbent may be better off if he or she does not provide—or does not provide a fair pay to public scientists. We propose a simple game-theoretic model for understanding the trust problem in the relationship between governments and scientists. The model shows how with reliable governments (democracies), bureaucratic contracts (e.g., secure tenure) are not optimal since they have low-powered incentives (in contrast to the highpowered private-sector type of contracts) and run against scientists’ responsiveness to government demands. However, with nonreliable governments (dictatorships), bureaucratic contracts are second-best solutions because they protect scientists against the possibility of governments’ misbehavior (i.e., ex post opportunistic defections, such as canceling research programs overnight). An empirical analysis confirms the predictions: bureaucratic contracts enhance scientific productivity with nonreliable governments (dictatorships) but hamper scientific productivity with reliable governments (democracies).Publicad

Markets, herding and response to external information

We focus on the influence of external sources of information upon financial markets. In particular, we develop a stochastic agent-based market model characterized by a certain herding behavior as well as allowing traders to be influenced by an external dynamic signal of information. This signal can be interpreted as a time-varying advertising, public perception or rumor, in favor or against one of two possible trading behaviors, thus breaking the symmetry of the system and acting as a continuously varying exogenous shock. As an illustration, we use a well-known German Indicator of Economic Sentiment as information input and compare our results with Germany's leading stock market index, the DAX, in order to calibrate some of the model parameters. We study the conditions for the ensemble of agents to more accurately follow the information input signal. The response of the system to the external information is maximal for an intermediate range of values of a market parameter, suggesting the existence of three different market regimes: amplification, precise assimilation and undervaluation of incoming information.Comment: 30 pages, 8 figures. Thoroughly revised and updated version of arXiv:1302.647

Description and Optimization of Abstract Machines in a Dialect of Prolog

In order to achieve competitive performance, abstract machines for Prolog and related languages end up being large and intricate, and incorporate sophisticated optimizations, both at the design and at the implementation levels. At the same time, efficiency considerations make it necessary to use low-level languages in their implementation. This makes them laborious to code, optimize, and, especially, maintain and extend. Writing the abstract machine (and ancillary code) in a higher-level language can help tame this inherent complexity. We show how the semantics of most basic components of an efficient virtual machine for Prolog can be described using (a variant of) Prolog. These descriptions are then compiled to C and assembled to build a complete bytecode emulator. Thanks to the high level of the language used and its closeness to Prolog, the abstract machine description can be manipulated using standard Prolog compilation and optimization techniques with relative ease. We also show how, by applying program transformations selectively, we obtain abstract machine implementations whose performance can match and even exceed that of state-of-the-art, highly-tuned, hand-crafted emulators.Comment: 56 pages, 46 figures, 5 tables, To appear in Theory and Practice of Logic Programming (TPLP

Rubio de Francia's extrapolation theory: estimates for the distribution function

Let $T$ be an arbitrary operator bounded from $L^{p_0}(w)$ into $L^{p_0, \infty}(w)$ for every weight $w$ in the Muckenhoupt class $A_{p_0}$. It is proved in this article that the distribution function of $Tf$ with respect to any weight $u$ can be essentially majorized by the distribution function of $Mf$ with respect to $u$ (plus an integral term easy to control). As a consequence, well-known extrapolation results, including results in a multilinear setting, can be obtained with very simple proofs. New applications in extrapolation for two-weight problems and estimates on rearrangement invariant spaces are established too.Comment: 29 page