Evolution of unoccupied resonance during the synthesis of a silver dimer on Ag(111)

Silver dimers were fabricated on Ag(111) by single-atom manipulation using the tip of a cryogenic scanning tunnelling microscope. An unoccupied electronic resonance was observed to shift toward the Fermi level with decreasing atom-atom distance as monitored by spatially resolved scanning tunnelling spectroscopy. Density functional calculations were used to analyse the experimental observations and revealed that the coupling between the adsorbed atoms is predominantly direct rather than indirect via the Ag(111) substrate.Comment: 9 pages, 3 figure

Time-dependent density functional theory calculation of van der Waals coefficient of sodium clusters

In this paper we employ all-electron \textit{ab-initio} time-dependent density functional theory based method to calculate the long range dipole-dipole dispersion coefficient (van der Waals coefficient) $C_{6}$ of sodium atom clusters containing even number of atoms ranging from 2 to 20 atoms. The dispersion coefficients are obtained via Casimir-Polder relation. The calculations are carried out with two different exchange-correlation potentials: (i) the asymptotically correct statistical average of orbital potential (SAOP) and (ii) Vosko-Wilk-Nusair representation of exchange-correlation potential within local density approximation. A comparison with the other theoretical results has been performed. We also present the results for the static polarizabilities of sodium clusters and also compare them with other theoretical and experimental results. These comparisons reveal that the SAOP results for C_{6} and static polarizability are quite accurate and very close to the experimental results. We examine the relationship between volume of the cluster and van der Waals coefficient and find that to a very high degree of correlation C_{6} scales as square of the volume. We also present the results for van der Waals coefficient corresponding to cluster-Ar atom and cluster-N_{2} molecule interactions.Comment: 22 pages including 6 figures. To be published in Journal of Chemical Physic

The effects of swing-leg retraction on running performance: analysis, simulation, and experiment

Using simple running models, researchers have argued that swing-leg retraction can improve running robot performance. In this paper, we investigate whether this holds for a more realistic simulation model validated against a physical running robot. We find that swing-leg retraction can improve stability and disturbance rejection. Alternatively, swing-leg retraction can simultaneously reduce touchdown forces, slipping likelihood, and impact energy losses. Surprisingly, swing-leg retraction barely affected net energetic efficiency. The retraction rates at which these effects are the greatest are strongly model-dependent, suggesting that robot designers cannot always rely on simplified models to accurately predict such complex behaviors

A Simple Theory of Condensation

A simple assumption of an emergence in gas of small atomic clusters consisting of $c$ particles each, leads to a phase separation (first order transition). It reveals itself by an emergence of ``forbidden'' density range starting at a certain temperature. Defining this latter value as the critical temperature predicts existence of an interval with anomalous heat capacity behaviour $c_p\propto\Delta T^{-1/c}$. The value $c=13$ suggested in literature yields the heat capacity exponent $\alpha=0.077$.Comment: 9 pages, 1 figur

German cancer statistics 2004

Background: For years the Robert Koch Institute (RKI) has been annually pooling and reviewing the data from the German population-based cancer registries and evaluating them together with the cause-of-death statistics provided by the statistical offices. Traditionally, the RKI periodically estimates the number of new cancer cases in Germany on the basis of the available data from the regional cancer registries in which registration is complete; this figure, in turn, forms the basis for further important indicators. Methods: This article gives a brief overview of current indicators - such as incidence, prevalence, mortality, survival rates - on the most common types of cancer, as well as important ratios on the risks of developing and dying of cancer in Germany. Results: According to the latest estimate, there were a total of 436,500 new cancer cases in Germany in 2004. The most common cancer in men is prostate cancer with over 58,000 new cases per annum, followed by colorectal and lung cancer. In women, breast cancer remains the most common cancer with an estimated 57,000 new cases every year, also followed by colorectal cancer. These and further findings on selected cancer sites can be found in the current brochure on “Cancer in Germany”, which is regularly published by the RKI together with the Association of Population-based Cancer Registries in Germany (GEKID). In addition, the RKI made cancer-prevalence estimates and calculated current morbidity and mortality risks at the federal level for the first time. According to these figures, the 5-year partial prevalence - i.e. the total number of cancer patients diagnosed over the past five years who are currently still living - exceeds 600,000 in men; the figure is about the same among women. Here, too, the most common cancers are prostate cancer in men and breast cancer in women. The lifetime risk of developing cancer, which is more related to the individual, is estimated to be higher among men (48.5%) than among women (40.3%). In roughly rounded figures, therefore, about every second person in Germany develops cancer in the course of their lives. One in four men and one in five women die of cancer. Conclusions: In recent years, population-based cancer registration in Germany has come significantly closer to the aim of the complete, nationwide coverage of cancer. The continuous improvements in the data situation help describe cancer development in Germany

Project WILAS – West Iberia Lithosphere and Astenosphere Structure

The lithosphere of Iberia has been formed through a number of processes of continental collision and extension: in Lower Paleozoic, the collision of three tectonics blocks produced the Variscan Orogeny, the main event of formation of the lithosphere. The subsequent Mesozoic rifting and breakup of the Pangea had a profound effect on the continental crust of Iberia. Since the Miocene, the southern interaction between Africa and Iberia is characterized by a diffuse convergent margin that originates a vast area of deformation. The impact of this complex tectonic in the structure of the Lithosphere remains an incognito, especially in its western part. Project WILAS (PTDC/CTE-GIX/097946/2008) is a 3 years project funded by FCT in which a temporary network of more than 20 BB seismic stations is being deployed in Portugal between 2010-2012. It will extend to the western border of Iberia the coverage of the TOPO-IBERIA project. The project aims to image the 3D structure beneath W Iberia. The knowledge of the Crust, Lithosphere and Astenosphere seismic structure must be dealt at different scales, involving different but complementary methods