Magnetic properties of the spin S=1/2S=1/2 Heisenberg chain with hexamer modulation of exchange

We consider the spin-1/2 Heisenberg chain with alternating spin exchange %on even and odd sites in the presence of additional modulation of exchange on odd bonds with period three. We study the ground state magnetic phase diagram of this hexamer spin chain in the limit of very strong antiferromagnetic (AF) exchange on odd bonds using the numerical Lanczos method and bosonization approach. In the limit of strong magnetic field commensurate with the dominating AF exchange, the model is mapped onto an effective $XXZ$ Heisenberg chain in the presence of uniform and spatially modulated fields, which is studied using the standard continuum-limit bosonization approach. In absence of additional hexamer modulation, the model undergoes a quantum phase transition from a gapped string order into the only one gapless L\"uttinger liquid (LL) phase by increasing the magnetic field. In the presence of hexamer modulation, two new gapped phases are identified in the ground state at magnetization equal to 1/3 and 2/3 of the saturation value. These phases reveal themselves also in magnetization curve as plateaus at corresponding values of magnetization. As the result, the magnetic phase diagram of the hexamer chain shows seven different quantum phases, four gapped and three gapless and the system is characterized by six critical fields which mark quantum phase transitions between the ordered gapped and the LL gapless phases.Comment: 21 pages, 5 figures, Journal of Physics: Condensed Matter, 24, 116002, (2012

Violating Bell inequality using weak coherent states

We present an experimental investigation of two-photon interference using a continuous-wave laser. We demonstrate the violation of the CHSH inequality using the phase randomized weak coherent states from a continuous wave laser. Our implementation serves as an approach to reveal the quantum nature of a source that is considered to be a classical source.Comment: 6 pages, 2 figure

The gap exponent of XXZ model in a transverse field

We have calculated numerically the gap exponent of the anisotropic Heisenberg model in the presence of the transverse magnetic field. We have implemented the modified Lanczos method to obtain the excited states of our model with the same accuracy of the ground state. The coefficient of the leading term in the perturbation expansion diverges in the thermodynamic limit (N --> infinity). We have obtained the relation between this divergence and the scaling behaviour of the energy gap. We have found that the opening of gap in the presence of transverse field scales with a critical exponent which depends on the anisotropy parameter (Delta). Our numerical results are in well agreement with the field theoretical approach in the whole range of the anisotropy parameter, -1 < Delta < 1.Comment: 6 pages and 4 figure

Epidemiology, incidence and mortality of bladder cancer and their relationship with the development index in the world

Background: Bladder cancer is an international public health problem. It is the ninth most common cancer and the fourteenth leading cause of death due to cancer worldwide. Given aging populations, the incidence of this cancer is rising. Information on the incidence and mortality of the disease, and their relationship with level of economic development is essential for better planning. The aim of the study was to investigate bladder cancer incidence and mortality rates, and their relationship with the the Human Development Index (HDI) in the world. Materials and Methods: Data were obtained from incidence and mortality rates presented by GLOBOCAN in 2012. Data on HDI and its components were extracted from the global bank site. The number and standardized incidence and mortality rates were reported by regions and the distribution of the disease were drawn in the world. For data analysis, the relationship between incidence and death rates, and HDI and its components was measured using correlation coefficients and SPSS software. The level of significance was set at 0.05. Results: In 2012, 429,793 bladder cancer cases and 165,084 bladder death cases occurred in the world. Five countries that had the highest age-standardized incidence were Belgium 17.5 per 100,000, Lebanon 16.6/100,000, Malta 15.8/100,000, Turkey 15.2/100,000, and Denmark 14.4/100,000. Five countries that had the highest age-standardized death rates were Turkey 6.6 per 100,000, Egypt 6.5/100,000, Iraq 6.3/100,000, Lebanon 6.3/100,000, and Mali 5.2/100,000. There was a positive linear relationship between the standardized incidence rate and HDI (r=0.653, P<0.001), so that there was a positive correlation between the standardized incidence rate with life expectancy at birth, average years of schooling, and the level of income per person of population. A positive linear relationship was also noted between the standardized mortality rate and HDI (r=0.308, P<0.001). There was a positive correlation between the standardized mortality rate with life expectancy at birth, average years of schooling, and the level of income per person of population. Conclusions: The incidence of bladder cancer in developed countries and parts of Africa was higher, while the highest mortality rate was observed in the countries of North Africa and the Middle East. The program for better treatment in developing countries to reduce mortality from the cancer and more detaiuled studies on the etiology of are essential

Spatial analysis of breast cancer incidence in Iran

Breast cancer (BC) is the most common cancer in females (27 of the total) and the main cause of death (16) due to cancer in women in developed and developing countries. Variations in its incidence rate among geographical areas are due to various contributing factors. Since there have been a lack of studies on this topic in our country, the present spatial analysis of breast cancer incidence in Iran in 2009 was conducted using data from the national cancer registry system. The reported incidences of the disease were standardized according to the World Health Organization population and the direct method. Then data was inserted into the GIS software and finally, using the Hot Spot Analysis (Geties-Ord Gi), high-risk areas were drawn. Provinces with incidences 1.96 SD higher or lower than the national average were considered as hot spots or cold spots, at the significance level of 0.05. In 2009, a total of 7,582 cases of BC occurred in Iran. The annual incidence was 33.2 per hundred thousand people. Our study showed that the highest incidence of BC in women occurred in the central provinces of the country, Tehran, Isfahan, Yazd, Markazi and Fars. The results of hot spots analysis showed that the distribution of high-risk BC was focused in central parts of Iran, especially Isfahan province (p < 0.01). The other provinces were not significantly different from the national average. The higher incidence in central provinces may be due to greater exposure to carcinogens in urban areas, a Western lifestyle and high prevalence of other risk factors. Further epidemiological studies about the etiology and early detection of BC are essential. © 2016, Asian Pacific Journal of Cancer Prevention

Trend of incidence of gastric cancer in sistan and Baluchestan province, Iran

Objective: Gastric cancer is the fifth most common cancer and the third cause of death from cancers in the world and is known as the most deadly cancer in Iran. Since the knowledge about the epidemiological situation and the trend of incidence of this cancer is essential to plan for the prevention and treatment of cancer, this study was performed with the aim of investigating the epidemiological status, the rate and the trend of gastric cancer incidence in Sistan and Baluchestan province. Methods: This study was conducted using existing data and data extracted from the National Cancer Registry System and the Disease Management Center of Iranian Ministry of Health between 2003 and 2008. Age-Standardized incidence rates (ASIR) were calculated using the world standard population. The crude incidence rate was also computed. Cochran�Armitage test for linear trend was used for evaluation of the incidence trend. Results: The number of 255 cases of gastric cancer occurred in the study period that 188 cases were in men and 67 in women. Accordingly, the incidence of gastric cancer has had an ascending trend in Sistan and Baluchestan (p=0.00) and its incidence in men and women has changed to 1.18 and 2.73 in 2004 to 1.84 and 4.48 in 2008, respectively. Furthermore, with ageing, the incidence of gastric cancer has increased in both sexes and its incidence was higher in men than women. Conclusion: The incidence of gastric cancer has an increasing trend in Sistan and Baluchestan, hence, etiological surveys and programs of early diagnosis are useful in this province to the reduce cancer. © 2016 The Authors. Published by Innovare Academic Sciences Pvt Ltd

Heat capacity of Schottky type in low-dimensional spin system

The heat capacity of low-dimensional spin systems is studied using theoretical and numerical techniques. Keeping only two energy states, the system is mapped onto the two -level-system (TLS) model. Using the low temperature Lanczos method, it is confirmed that the behavior of $T_{M}$ and the energy gap as functions of the control parameter is the same in the two models studied; a conclusion that can probably be extrapolated to the general case of any system that possesses an energy gap.Comment: 7 pages, 5 figure

1D Frustrated Ferromagnetic Model with Added Dzyaloshinskii-Moriya Interaction

The one-dimensional (1D) isotropic frustrated ferromagnetic spin-1/2 model is considered. Classical and quantum effects of adding a Dzyaloshinskii-Moriya (DM) interaction on the ground state of the system is studied using the analytical cluster method and numerical Lanczos technique. Cluster method results, show that the classical ground state magnetic phase diagram consists of only one single phase: "chiral". The quantum corrections are determined by means of the Lanczos method and a rich quantum phase diagram including the gapless Luttinger liquid, the gapped chiral and dimer orders is obtained. Moreover, next nearest neighbors will be entangled by increasing DM interaction and for open chains, end-spins are entangled which shows the long distance entanglement (LDE) feature that can be controlled by DM interaction.Comment: 8 pages, 9 figure