Electronic coupling between Bi nanolines and the Si(001) substrate: An experimental and theoretical study

Atomic nanolines are one dimensional systems realized by assembling many atoms on a substrate into long arrays. The electronic properties of the nanolines depend on those of the substrate. Here, we demonstrate that to fully understand the electronic properties of Bi nanolines on clean Si(001) several different contributions must be accounted for. Scanning tunneling microscopy reveals a variety of different patterns along the nanolines as the imaging bias is varied. We observe an electronic phase shift of the Bi dimers, associated with imaging atomic p-orbitals, and an electronic coupling between the Bi nanoline and neighbouring Si dimers, which influences the appearance of both. Understanding the interplay between the Bi nanolines and Si substrate could open a novel route to modifying the electronic properties of the nanolines.Comment: 6 pages (main), 2 pages (SI), accepted by Phys. Rev.

Do Walmartians Rule? The Political Influence of the Emerging Middle Class

The present paper tries to answer the following question: did an increase in the consumption of durable goods -such as electric appliances- help the incumbent party to retain the Mexican presidency in 2006? Stated differently, did the middle class vote to support the current economic model? Important data limitations made the use of indirect tests and correlations necessary, rather than causalities -with the associated identification problems. Nonetheless, the paper was not able to reject the hypothesis mentioned above. In a tight election, a small effect could make the difference; and this analysis suggests that this is likely what happenedvoting, welfare, durable goods, middle class

Casimir-like tunneling-induced electronic forces

We study the quantum forces that act between two nearby conductors due to electronic tunneling. We derive an expression for these forces by calculating the flux of momentum arising from the overlap of evanescent electronic fields. Our result is written in terms of the electronic reflection amplitudes of the conductors and it has the same structure as Lifshitz's formula for the electromagnetically mediated Casimir forces. We evaluate the tunneling force between two semiinfinite conductors and between two thin films separated by an insulating gap. We discuss some applications of our results.Comment: 8 pages, 3 figs, submitted to Proc. of QFEXT'05, to be published in J. Phys.

High-multipolar effects on the Casimir force: the non-retarded limit

We calculate exactly the Casimir force or dispersive force, in the non-retarded limit, between a spherical nanoparticle and a substrate beyond the London's or dipolar approximation. We find that the force is a non-monotonic function of the distance between the sphere and the substrate, such that, it is enhanced by several orders of magnitude as the sphere approaches the substrate. Our results do not agree with previous predictions like the Proximity theorem approach.Comment: 7 pages including 2 figures. Submitted to Europjysics Letter

Spectral representation of the Casimir Force Between a Sphere and a Substrate

We calculate the Casimir force in the non-retarded limit between a spherical nanoparticle and a substrate, and we found that high-multipolar contributions are very important when the sphere is very close to the substrate. We show that the highly inhomegenous electromagnetic field induced by the presence of the substrate, can enhance the Casimir force by orders of magnitude, compared with the classical dipolar approximation.Comment: 5 page + 4 figures. Submitted to Phys. Rev. Let

Supporting clinical information management by NFC technology

Tele-monitorization is a problem with aging people living alone since the vital signs control is complicated for them. In this sense, some initiatives by adapting technologies make easy these controls. In this work we present a solution consist of the Near Field Communications technology adaptability. Mobile phones NFC enabled serving as a middleware between measure devices and people. In addition, a proposal for managing clinical information and medicine prescription are presented.Tele-monitorization is a problem with aging people living alone since the vital signs control is complicated for them. In this sense, some initiatives by adapting technologies make easy these controls. In this work we present a solution consist of the Near Field Communications technology adaptability. Mobile phones NFC enabled serving as a middleware between measure devices and people. In addition, a proposal for managing clinical information and medicine prescription are presented

Correlation between obesity and severity of distal radius fractures

Introduction: The incidence of obesity has increased significantly worldwide. Our hypothesis was that patients with obesity have a more severe distal radius fracture and we realized a study to evaluate this correlation between obesity and severity of distal radius fractures caused by low-energy injuries. Materials and methods: A total of 114 patients with distal radius fracture were examined in

DESCRIPCIÓN MORFOMÉTRICA DE DOS POBLACIONES DE Leiosporoceros dussii (STEPHANI) HÄSSEL (LEIOSPOROCEROTACEAE) DE PANAMÁ

Leiosporoceros dussii (Stephani) Hässel is a neotropical genus of hornwort with little exiting morphological information. This is the only hornwort reported with cyanobacterial colonies present in longitudinally oriented schizogenous canals through the thallus, which is a diagnostic feature for its identification. The aim of this study was to describe the morphology of L. dussii using morphometrical analysis of two populations from El Valle de Anton, in the Cocle Province of Panama. Our analysis showed significant variations in both the gametophyte and the sporophyte when the two populations were compared using multivariate and univariate statistical analysis. This description is a valuable source for the identification of sterile plants of the species Leiosporoceros dussii and expand our knowledge of this phylogenetically important species. Leiosporoceros dussii es un antocerote neotropical que comprende colonias de cianobacterias alojadas en canales esquizógenos ramificados dicotómicamente a lo largo del talo, esta particularidad representa un carácter diagnostico utilizado para diferenciar esta especie de otros antocerotes. Este trabajo tiene como objetivo estudiar la variación morfológica de L. dussii, por medio de análisis morfométricos de dos poblaciones, ubicadas en El Valle de Antón, provincia de Coclé, Panamá. Se realizó una descripción completa de la especie y se encontraron variaciones morfométricas entre las dos poblaciones. Se compararon características morfométricas de las poblaciones estudiadas, las cuales mostraron variaciones morfométricas significativas, evidenciadas tanto en el análisis de datos multivariante como univariante. Este estudio proporciona descripciones morfométricas detalladas del gametófito y esporófito de L. dussii, las cuales pueden ser utilizadas para la identificación de especímenes sin estructuras reproductivas

Critical materials supply and risk

Rare earth Elements (REEs) are a subset of Critical materials (CMs) and are found in numerous modern electronic products and advanced technologies where, due to their unique physical and chemical properties, they cannot be substituted. Disruption in their supply chain has the potential to cause devastating impacts on production and consumers. To help manage such disruptions, this research focusses on the areas of critical materials, supply chain resilience, and supply chain risk. Research has established the challenges that can occur from disruptions caused by up-stream suppliers, necessitating supply-side resilience strategies. Supply-side risk factors associated with CMSs differ from conventional material supply chain risk, and it is advocated that they cannot be effectively managed through traditional material supply risk management practices. This study investigates the research on CMs that appears around the periphery of the OM (operations management) field by adopting a systematic literature review. Findings show a dearth of research work directly focused on REEs and CMs from within the OM field. Importantly, a call is made for OM researchers to investigate REEs and CMs based on the imperative that geopolitics, resource scarcity and environmental issues present

U B V R I Photometry of Stellar Structures throughout the Disk of the Barred Galaxy NGC 3367

We report new detailed surface U, B, V, R, and I photometry of 81 stellar structures in the disk of the barred galaxy NGC 3367. The images show many different structures indicating that star formation is going on in the most part of the disk. NGC 3367 is known to have a very high concentration of molecular gas distribution in the central regions of the galaxy and bipolar synchrotron emission from the nucleus with two lobes (at 6 kpc) forming a triple structure similar to a radio galaxy. We have determined the U, B, V, R, and I magnitudes and U - B, B - V, U - V, and V - I colors for the central region (nucleus), a region which includes supernovae 2003 AA, and 79 star associations throughout NGC 3367. Estimation of ages of star associations is very difficult due to several factors, among them: filling factor, metallicity, spatial distribution of each structure and the fact that we estimated the magnitudes with a circular aperture of 16 pixels in diameter, equivalent to $6''.8\sim1.4$ kpc. However, if the colors derived for NGC 3367 were similar to the colors expected of star clusters with theoretical evolutionary star tracks developed for the LMC and had a similar metallicity, NGC 3367 show 51 percent of the observed structures with age type SWB I (few tens of Myrs), with seven sources outside the bright surface brightness visible disk of NGC 3367.Comment: Accepted for publication (abr 2007) in The Astronomical Journal (July 2007 issue