Effects of nanoscale spatial inhomogeneity in strongly correlated systems

We calculate ground-state energies and density distributions of Hubbard superlattices characterized by periodic modulations of the on-site interaction and the on-site potential. Both density-matrix renormalization group and density-functional methods are employed and compared. We find that small variations in the on-site potential $v_i$ can simulate, cancel, or even overcompensate effects due to much larger variations in the on-site interaction $U_i$. Our findings highlight the importance of nanoscale spatial inhomogeneity in strongly correlated systems, and call for reexamination of model calculations assuming spatial homogeneity.Comment: 5 pages, 1 table, 4 figures, to appear in PR

Contact mechanics analysis of a soft robotic fingerpad

The precision grasping capabilities of robotic hands is a key feature which is more and more required in the manipulation of objects in several unstructured fields, as for instance industrial, medical, agriculture and food industry. For this purpose, the realization of soft robotic fingers is crucial to reproduce the human finger skills. From this point of view the fingerpad is the part which is mostly involved in the contact. Particular attention must be paid to the knowledge of the mechanical contact behavior of soft artificial fingerpads. In this paper, artificial silicone fingerpads are applied to the last phalanx of robotic fingers actuated by tendons. The mechanical interaction between the fingerpad and a flat surface is analyzed in terms of deformations, contact areas and indentations. A reliable model of fingertip deformation properties provides important information for understanding robotic hand performance, that can be useful both in the design phase and for defining control strategies. The approach is based on theoretical, experimental, and numerical methods. The results will be exploited for the design of more effective robotic fingers for precision grasping of soft or fragile objects avoiding damages

Magnetic Susceptibility of an integrable anisotropic spin ladder system

We investigate the thermodynamics of a spin ladder model which possesses a free parameter besides the rung and leg couplings. The model is exactly solved by the Bethe Ansatz and exhibits a phase transition between a gapped and a gapless spin excitation spectrum. The magnetic susceptibility is obtained numerically and its dependence on the anisotropy parameter is determined. A connection with the compounds KCuCl3, Cu2(C5H12N2)2Cl4 and (C5H12N)2CuBr4 in the strong coupling regime is made and our results for the magnetic susceptibility fit the experimental data remarkably well.Comment: 12 pages, 12 figures included, submitted to Phys. Rev.

European cancer mortality predictions for the year 2012

Background: Estimating current cancer mortality figures is important for defining priorities for prevention and treatment. Materials and methods: Using logarithmic Poisson count data joinpoint models on mortality and population data from the World Health Organization database, we estimated numbers of deaths and age-standardized rates in 2012 from all cancers and selected cancer sites for the whole European Union (EU) and its six more populated countries. Results: Cancer deaths in the EU in 2012 are estimated to be 1 283 101 (717 398 men and 565 703 women) corresponding to standardized overall cancer death rates of 139/100 000 men and 85/100 000 women. The fall from 2007 was 10% in men and 7% in women. In men, declines are predicted for stomach (−20%), leukemias (−11%), lung and prostate (−10%) and colorectal (−7%) cancers, and for stomach (−23%), leukemias (−12%), uterus and colorectum (−11%) and breast (−9%) in women. Almost stable rates are expected for pancreatic cancer (+2-3%) and increases for female lung cancer (+7%). Younger women show the greatest falls in breast cancer mortality rates in the EU (−17%), and declines are expected in all individual countries, except Poland. Conclusion: Apart for lung cancer in women and pancreatic cancer, continuing falls are expected in mortality from major cancers in the E

European cancer mortality predictions for the year 2015: does lung cancer have the highest death rate in EU women?

Total cancer mortality rates in the EU are predicted to fall 7.5% in men and 6% in women between 2009 and 2015. However, due to population aging, total number of cancer deaths will rise to 1 359 100. Cancer mortality outlook for 2015 remains favourable, except for pancreas in both sexes and female lung that is predicted to overtake breast becoming the female cancer with the highest rate (14.24/100 000

Trends in cancer mortality in the Americas, 1970-2000

Background: Data and statistics on cancer mortality over the last decades are available for most developed countries, while they are more difficult to obtain, in a standardized and comparable format, for countries of Latin America. Patients and methods: Age standardized (world population) mortality rates around the year 2000, derived from the WHO database, are presented for 14 selected cancers and total cancer in 10 countries of Latin America, plus, for comparative purposes, Canada and the USA. Trends in mortality are also given over the period 1970-2000. Results: In 2000, the highest total cancer mortality for males was observed in Argentina and Chile, with rates comparable to those of Canada and the USA, i.e. about 155/100 000. For women, Chile and Cuba had the highest rates in Latin America (114 and 103/100 000, respectively), again comparable to those of North America (around 105/100 000). These reflect the comparatively high mortality from cancer of the stomach (for Chile), lung and intestines (for Argentina) in men, and of stomach and uterus (for Chile), intestines and lung (for Cuba) in women. Colombia, Ecuador and Mexico had the lowest total cancer mortality for men, due to low mortality from stomach, colorectal and lung cancer. For women, the lowest rates were in Brazil and Puerto Rico, reflecting their low stomach and cervical cancer rates. In Argentina, Chile, Colombia, Costa Rica and Venezuela cancer mortality rates tended to decline, particularly in men. Rates were stable in Ecuador and Puerto Rico, and were increasing in Mexico and Cuba. Conclusions: Mortality from some common cancers (including colorectal and lung) is still low in Latin America compared with Canada and the USA, and decreasing trends have been observed in the last decades for some cancer sites (including stomach, uterus, lung and other tobacco-related cancers) in several countries. However, mortality from female lung and breast cancers has been increasing in most countries of Latin America, and several countries still show an extremely elevated mortality from cancer of the cervix. Selected neoplasms amenable to treatment, including testis and leukemias, also show unsatisfactory trends in Latin Americ

Trends in cancer mortality in Mexico, 1970-1999

Background: Few data on cancer mortality have been published for Mexico over the last few decades. It is therefore of interest to conduct a systematic and updated analysis of cancer mortality in this country. Patients and methods: Age-standardised (world population) mortality rates, at all ages and truncated at age 35-64 years, from major cancers and all cancers combined were computed on the basis of certified deaths derived from the World Health Organization database for the period 1970-99. Results: Mortality rates for all neoplasms showed an upward trend in men of all ages (from 58.2/100 000 in 1970-74 to 87.1/100 000 in 1995-99) and in middle-aged men (from 76.1 to 93.7/100 000, respectively). This reflects the rise until the early 1990s in lung cancer mortality (from 8.1/100 000 in 1970-74 to 15.6/100 000 in 1995-99) and prostate cancer (from 5.5 to 12.2/100 000, respectively). In women, overall mortality rates showed an increase between the early 1970s (75.4/100 000) and the late 1990s (82.3/100 000). Total cancer mortality rates remained low, however, compared with other American countries (e.g. 153.3/100 000 men and 108.6/100 000 women in 1999 in the United States). Truncated rates were stable (126.5/100 000 in 1970-74 and 125.8/100 000 in 1995-99), although they were much higher than overall rates, reflecting exceedingly high rates for uterine (mostly cervical) cancer mortality in middle-aged women (29.5/100 000 in 1995-99). Conclusions: Total cancer mortality in Mexico has remained comparably low on a worldwide scale, and the upward trends in mortality rates for lung and other tobacco-related neoplasms have tended to level off over the last decade. However, steady rises have been observed for other major cancers, including prostate and breast. Cervical cancer remains a major health problem in wome