Topological Phase Transitions in Periodically Modulated Quantized Metal Films

Electronic topological phase transitions (ETT) are predicted for any quantized metal films with a periodically modulated boundary commensurate with the bulk lattice. While the thickness of the film at which ETT occurs is determined almost exclusively by the period of the boundary modulation, the value of the band gaps and the amplitude of the singularities are proportional to the amplitude of the corrugation. The gaps in the energy spectrum lead to a strong anisotropy of conductivity. These novel quantum effects can be detected in measurements of the density of states and conductivity as a function of the film thickness. Experiments that could lead to these observations are proposed

Spatiotemporal Scan and Age-Period-Cohort Analysis of Hepatitis C Virus in Henan, China: 2005–2012

Background: Studies have shown that hepatitis C virus (HCV) infection increased during the past decades in China. However, little evidence is available on when, where, and who were infected with HCV. There are gaps in knowledge on the epidemiological burden and evolution of the HCV epidemic in China. Methods: Data on HCV cases were collected by the disease surveillance system from 2005 to 2012 to explore the epidemic in Henan province. Spatiotemporal scan statistics and age-period-cohort (APC) model were used to examine the effects of age, period, birth cohort, and spatiotemporal clustering. Results: 177,171 HCV cases were reported in Henan province between 2005 and 2012. APC modelling showed that the HCV reported rates significantly increased in people aged > 50 years. A moderate increase in HCV reported rates was observed for females aged about 25 years. HCV reported rates increased over the study period. Infection rates were greatest among people born between 1960 and 1980. People born around 1970 had the highest relative risk of HCV infection. Women born between 1960 and 1980 had a five-fold increase in HCV infection rates compared to men, for the same birth cohort. Spatiotemporal mapping showed major clustering of cases in northern Henan, which probably evolved much earlier than other areas in the province. Conclusions: Spatiotemporal mapping and APC methods are useful to help delineate the evolution of the HCV epidemic. Birth cohort should be part of the criteria screening programmes for HCV in order to identify those at highest risk of infection and unaware of their status. As Henan is unique in the transmission route for HCV, these methods should be used in other high burden provinces to help identify subpopulations at risk

Synthesis of Hollow ZnSnO 3

Hollow ZnSnO3 nanospheres were synthesized by a hydrothermal method using ZnO nanospheres as the hard template and raw material simultaneously. The combined characterizations of X-ray diffraction (XRD), scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HRTEM) confirmed the successful preparation of hollow ZnSnO3 nanospheres. The gas-sensing results indicated that the sensor made from hollow ZnSnO3 nanospheres exhibited high sensitivity, good selectivity, and stability to ethanol at a low operating temperature of 200°C. The sensitivity was about 32 and the response and recovery time were about 4 s and 30 s for 100 ppm ethanol, respectively. The enhancement in gas-sensing properties was attributed to the hollow nanostructures and high specific surface areas of ZnSnO3

A Physical Basis for the Probabilistic Prediction of the Accumulated Tropical Cyclone Kinetic Energy in the Western North Pacific

The relationship between El Nino-Southern Oscillation (ENSO) andtropical storm (TS) activity over the western North Pacific Ocean is examined for the period from 1981 to 2010. In El Nino years, TS genesis locations are generally shifted to the southeast relative to normal years and the passages of TSs tend to recurve to the northeast. TSs of greater duration and more intensity during an El Nino summer induce an increase of the accumulated tropical cyclone kinetic energy (ACE). Based on the strong relationship between the TS properties and ENSO, a probabilistic predictionfor seasonal ACE is investigated using a hybrid dynamical-statistical model. A statistical relationship is developed between the observed ACE and largescale variables taken from the ECMWF seasonal forecast system 4 hindcasts.The ACE correlates positively with the SST anomaly over the central to eastern Pacific and negatively with the vertical wind shear near the date line.The vertical wind shear anomalies over the central and western Pacific are selected aspredictors based on sensitivity tests of ACE predictive skill. The hybrid model performs quite well in forecasting seasonal ACE with a correlation coefficient between the observed and predicted ACE at 0.80 over the30-yr period. A relative operating characteristic analysis also indicates that the ensembles have significant probabilistic skill for both the above-normal and below-normal categories. By comparing the ACE prediction over theperiod from 2003 to 2011, the hybrid model appears more skillful than the forecast from the Tropical Storm Risk consortium.open1