Adsorption of Xe atoms on metal surfaces: New insights from first-principles calculations

The adsorption of rare gases on metal surfaces serve as the paradigm of weak adsorption where it is typically assumed that the adsorbate occupies maximally coordinated hollow sites. Density-functional theory calculations using the full-potential linearized augmented plane wave method for Xe adatoms on Mg(0001), Al(111), Ti(0001), Cu(111), Pd(111), and Pt(111), show, however, that Xe prefers low-coordination on-top sites in all cases. We identify the importance of polarization and a site-dependent Pauli repulsion in actuating the site preference and the principle nature of the rare-gas atom--metal surface interaction.Comment: 5 pages including 4 figure files. Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

Territorial rights and open borders

Territorial rights consist of the right to jurisdiction, the right to resources and the right to exclude immigrants and are assumed to be essential to state sovereignty. Scholars who have discussed the justification of these rights have mostly focused on the right to jurisdiction. Few engage with the implications of such justification for the right to exclude immigrants. This paper argues that the justification for territorial rights cannot justify the right of states to exclude immigrants. Allowing immigrants to settle within the territory does not undermine any of the interests territorial rights are meant to protect. In addition, the interests of current inhabitants do not provide sufficient reasons to grant the state the right to exclude immigrants from the territory that everyone has equal right to in an original situation. State sovereignty is therefore seen as compatible with open borders

Insightful classification of crystal structures using deep learning

Computational methods that automatically extract knowledge from data are critical for enabling data-driven materials science. A reliable identification of lattice symmetry is a crucial first step for materials characterization and analytics. Current methods require a user-specified threshold, and are unable to detect average symmetries for defective structures. Here, we propose a machine-learning-based approach to automatically classify structures by crystal symmetry. First, we represent crystals by calculating a diffraction image, then construct a deep-learning neural-network model for classification. Our approach is able to correctly classify a dataset comprising more than 100 000 simulated crystal structures, including heavily defective ones. The internal operations of the neural network are unraveled through attentive response maps, demonstrating that it uses the same landmarks a materials scientist would use, although never explicitly instructed to do so. Our study paves the way for crystal-structure recognition of - possibly noisy and incomplete - three-dimensional structural data in big-data materials science.Comment: Nature Communications, in press (2018

The Politicization And Death Of Rebus Sic Stantibus

Rebus sic stantibus is a doctrine which, in simple terms, holds that an agreement may, when certain conditions are met, be partially or wholly abrogated. OPEC nations threaten to use this doctrine to change aggreements with oil consuming trading partners

Using smart growth principles for development in St. Landry Parish

Since the end of World War II, many American cities have seen an outward migration from their core into open spaces along the city’s edge. The urban/suburban sprawl phenomenon not only affects urban cores but the rural lands and open spaces surrounding them. As landscape architects, we study humans and their interactions with the environment and have an important position in making informed decisions about issues of sprawl and unmitigated growth in communities. This study was conducted to provide city and parish officials and planning boards with options for beneficial growth in St. Landry Parish, a rural parish in south central Louisiana. A study of Smart Growth and its ten principles was completed. Also, three areas – Lancaster County Pennsylvania, Talbot County Maryland and the Wasatch Area in Utah - were examined for comparison and insight on how suburban sprawl had been mitigated in their communities. Recommendations for a comprehensive growth plan in St. Landry Parish were made based on the analysis of Smart Growth principles and case studies. It was determined that three Smart Growth principles would benefit the rural character and sense of place in St. Landry Parish. The principles were (1) preserve open space, farmland, natural beauty, and critical environmental areas (2) strengthen and direct development towards existing communities and (3) foster distinctive, attractive communities with a strong sense of place. Community involvement in the planning process and the establishment of community vision and goals were highly encouraged. Smart Growth can be used as a step stone in the planning process for St. Landry Parish

Public Health Ethics and Liberalism

This paper defends a distinctly liberal approach to public health ethics and replies to possible objections. In particular, I look at a set of recent proposals aiming to revise and expand liberalism in light of public health's rationale and epidemiological findings. I argue that they fail to provide a sociologically informed version of liberalism. Instead, they rest on an implicit normative premise about the value of health, which I show to be invalid. I then make explicit the unobvious, republican background of these proposals. Finally, I expand on the liberal understanding of freedom as non-interference and show its advantages over the republican alternative of freedom as non-domination within the context of public health. The views of freedom I discuss in the paper do not overlap with the classical distinction between negative and positive freedom. In addition, my account differentiates the concepts of freedom and autonomy and does not rule out substantive accounts of the latter. Nor does it confine political liberalism to an essentially procedural form

TCMI: a non-parametric mutual-dependence estimator for multivariate continuous distributions

The identification of relevant features, i.e., the driving variables that determine a process or the property of a system, is an essential part of the analysis of data sets whose entries are described by a large number of variables. The preferred measure for quantifying the relevance of nonlinear statistical dependencies is mutual information, which requires as input probability distributions. Probability distributions cannot be reliably sampled and estimated from limited data, especially for real-valued data samples such as lengths or energies. Here, we introduce total cumulative mutual information (TCMI), a measure of the relevance of mutual dependencies based on cumulative probability distributions. TCMI can be estimated directly from sample data and is a non-parametric, robust and deterministic measure that facilitates comparisons and rankings between feature sets with different cardinality. The ranking induced by TCMI allows for feature selection, i.e., the identification of the set of relevant features that are statistical related to the process or the property of a system, while taking into account the number of data samples as well as the cardinality of the feature subsets. We evaluate the performance of our measure with simulated data, compare its performance with similar multivariate dependence measures, and demonstrate the effectiveness of our feature selection method on a set of standard data sets and a typical scenario in materials science

Street crossing behavior in younger and older pedestrians: an eye- and head-tracking study

Background Crossing a street can be a very difficult task for older pedestrians. With increased age and potential cognitive decline, older people take the decision to cross a street primarily based on vehicles’ distance, and not on their speed. Furthermore, older pedestrians tend to overestimate their own walking speed, and could not adapt it according to the traffic conditions. Pedestrians’ behavior is often tested using virtual reality. Virtual reality presents the advantage of being safe, cost-effective, and allows using standardized test conditions. Methods This paper describes an observational study with older and younger adults. Street crossing behavior was investigated in 18 healthy, younger and 18 older subjects by using a virtual reality setting. The aim of the study was to measure behavioral data (such as eye and head movements) and to assess how the two age groups differ in terms of number of safe street crossings, virtual crashes, and missed street crossing opportunities. Street crossing behavior, eye and head movements, in older and younger subjects, were compared with non-parametric tests. Results The results showed that younger pedestrians behaved in a more secure manner while crossing a street, as compared to older people. The eye and head movements analysis revealed that older people looked more at the ground and less at the other side of the street to cross. Conclusions The less secure behavior in street crossing found in older pedestrians could be explained by their reduced cognitive and visual abilities, which, in turn, resulted in difficulties in the decision-making process, especially under time pressure. Decisions to cross a street are based on the distance of the oncoming cars, rather than their speed, for both groups. Older pedestrians look more at their feet, probably because of their need of more time to plan precise stepping movement and, in turn, pay less attention to the traffic. This might help to set up guidelines for improving senior pedestrians’ safety, in terms of speed limits, road design, and mixed physical-cognitive trainings