Combined effect of frustration and dimerization in ferrimagnetic chains and square lattice

Within the zero-temperature linear spin-wave theory we have investigated the effect of frustration and dimerization of a Heisenberg system with alternating spins $s_{1}$ and $s_{2}$ on one- and two-dimensional lattices. The combined effect most visibly appears in the elementary excitation spectra. In contrast to the ground state energy that decreases with dimerization and increases with frustration, the excitation energies are shown to be suppressed in energy by both dimerization and frustration. The threshold value of frustration that signals a transition from a classical ferrimagnetic state to a spiral state, decreases with dimerization, showing that dimerization further helps in the phase transition. The correlation length and sublattice magnetization decrease with both dimerization and frustration indicating the destruction of the long-range classical ferrimagnetic. The linear spin wave theory shows that in the case of a square lattice, dimerization initially opposes the frustration-led transition to a spiral magnetic state, but then higher magnitudes of lattice deformation facilitate the transition. It also shows that the transition to spiral state is inhibited in a square lattice beyond a certain value of dimerization.Comment: 8 pages, latex, 12 postscript figure

Knowledge and Attitudes of Young People toward Mental Illness: A Cross Sectional Study

The aim of the study was to investigate young Jordanians’ knowledge and attitudes toward people who have a mental illness. A cross sectional design was utilized. A convenient sample of 858 participants aged between 15–24 years old completed a survey. Participants under 19 years were accessed through their schools and those 19 years and above were accessed through universities. Results showed that although the majority of university and school students’ responses were generally consistent, they disagreed on 11 items on the survey; for example, 186 (39.3%) of university students agreed that mental illness has a biological origin compared with only 119 (30%) of school students. The majority of young people 737 (85.9%) were willing to learn and 792 (92.3%) felt that they have to help people with mental illness, which make them willing to learn. In conclusion, the findings provide insights for decision makers and researchers in Jordan about young peoples’ knowledge and attitudes toward mental illness. Increasing young adults’ literacy through introducing educational programs such as mental health first aid courses will enrich their knowledge; help change attitudes and reduce stigma toward people living with mental illness

The Reality of Distance Learning Skills among General Education Teachers from the Point of View of Supervisors and School Principals

This study examined the reality of distance learning skills among public education teachers from the point of view of supervisors and principals. The study aimed at identifying statistically significant differences in the average responses of the participants about the reality of distance learning skills among public education teachers in Asir region due to the study variables (job title, years of experience, gender, educational qualification, job rank, number of educational programs). The study used the descriptive approach to achieve the objectives of the study, and a questionnaire was designed for data collection and analysis. The study sample consisted of (245) supervisors and principals. The results of the study showed that the degree to which general education teachers possessed distance learning skills came to a large degree. The findings showed that there were no statistically significant differences in the average responses of respondents about distance learning skills due to the job title variable, and the presence of statistically significant differences in the average responses of the respondents about distance learning skills. The findings also revealed statistically significant differences in the averages of respondents’ responses about distance learning skills due to the variable of gender, with the exception of the field of “skills of using applied programs for information technology”, as well. The results showed that there were no statistically significant differences in the averages of the respondents’ responses about the areas of distance learning skills due to the educational qualification variable. There were statistically significant differences in the averages of the respondents’ responses in the areas of “educational software design skills, skills of using applied programs for information technology” due to the variable of occupational rank. There was a presence of statistically significant differences in the average responses of the respondents in the areas of skills of using application programs for information technology, due to the variable number of training programs

Polyimide-Planarized Vertical-Cavity Surface-Emitting Lasers With 17.0-GHz Bandwidth

Abstract-High-speed oxide-confined polyimide-planarized 850-nm vertical-cavity surface-emitting lasers exhibit 3-dB modulation bandwidths up to 17.0 GHz. The devices are fabricated using a reproducible, simple process incorporating polyimide with good adhesion that does not require implantation or semiinsulating substrates to achieve low capacitance

The hyperfine properties of a hydrogenated Fe/V superlattice

: We study the effect of hydrogen on the electronic, magnetic and hyperfine structures of an iron-vanadium superlattice consisting of three Fe monolayers and nine V monolayers. The contact charge density ({\rho}), the contact hyperfine field (Bhf) and the electronic field gradient (EFG) at the Fe sites for different H locations and H fillings are calculated using the first principle full-potential linear-augmented-plane-wave (FP-LAPW) method . It is found that sizeable changes in the hyperfine properties are obtained only when H is in the interface region.Comment: 6 pages, 2 figures, 3 tables, ICAME 2011 conference (Kobe, Japan

Critically ill patients with diabetes and Middle East respiratory syndrome:a multi-center observational study

Background: Diabetes is a risk factor for infection with coronaviruses. This study describes the demographic, clinical data, and outcomes of critically ill patients with diabetes and Middle East Respiratory Syndrome (MERS).Methods: This retrospective cohort study was conducted at 14 hospitals in Saudi Arabia (September 2012–January 2018). We compared the demographic characteristics, underlying medical conditions, presenting symptoms andsigns, management and clinical course, and outcomes of critically ill patients with MERS who had diabetes compared to those with no diabetes. Multivariable logistic regression analysis was performed to determine ifdiabetes was an independent predictor of 90-day mortality.Results: Of the 350 critically ill patients with MERS, 171 (48.9%) had diabetes. Patients with diabetes were more likely to be older, and have comorbid conditions, compared to patients with no diabetes. They were more likely topresent with respiratory failure requiring intubation, vasopressors, and corticosteroids. The median time to clearance of MERS-CoV RNA was similar (23 days (Q1, Q3: 17, 36) in patients with diabetes and 21.0 days (Q1, Q3: 10, 33) in patients with no diabetes). Mortality at 90 days was higher in patients with diabetes (78.9% versus 54.7%, p <0.0001). Multivariable regression analysis showed that diabetes was an independent risk factor for 90-day mortality(odds ratio, 2.09; 95% confidence interval, 1.18–3.72).Conclusions: Half of the critically ill patients with MERS have diabetes; which is associated with more severe disease. Diabetes is an independent predictor of mortality among critically patients with MERS

Trends of HIV-related cancer mortality between 2001 and 2018: an observational analysis

The burden of AIDS-defining cancers has remained relatively steady for the past two decades, whilst the burden of non-AIDS-defining cancer has increased. Here, we conduct a study to describe mortality trends attributed to HIV-associated cancers in 31 countries. We extracted HIV-related cancer mortality data from 2001 to 2018 from the World Health Organization Mortality Database. We computed age-standardized death rates (ASDRs) per 100,000 population using the World Standard Population. Data were visualized using Locally Weighted Scatterplot Smoothing (LOWESS). Data for females were available for 25 countries. Overall, there has been a decrease in mortality attributed to HIV-associated cancers among most of the countries. In total, 18 out of 31 countries (58.0%) and 14 out of 25 countries (56.0%) showed decreases in male and female mortality, respectively. An increasing mortality trend was observed in many developing countries, such as Malaysia and Thailand, and some developed countries, such as the United Kingdom. Malaysia had the greatest increase in male mortality (+495.0%), and Canada had the greatest decrease (-88.5%). Thailand had the greatest increase in female mortality (+540.0%), and Germany had the greatest decrease (-86.0%). At the endpoint year, South Africa had the highest ASDRs for both males (16.8/100,000) and females (19.2/100,000). The lowest was in Japan for males (0.07/100,000) and Egypt for females (0.028/100,000)

Critically ill patients with diabetes and Middle East respiratory syndrome:a multi-center observational study

Background: Diabetes is a risk factor for infection with coronaviruses. This study describes the demographic, clinical data, and outcomes of critically ill patients with diabetes and Middle East Respiratory Syndrome (MERS).Methods: This retrospective cohort study was conducted at 14 hospitals in Saudi Arabia (September 2012–January 2018). We compared the demographic characteristics, underlying medical conditions, presenting symptoms andsigns, management and clinical course, and outcomes of critically ill patients with MERS who had diabetes compared to those with no diabetes. Multivariable logistic regression analysis was performed to determine ifdiabetes was an independent predictor of 90-day mortality.Results: Of the 350 critically ill patients with MERS, 171 (48.9%) had diabetes. Patients with diabetes were more likely to be older, and have comorbid conditions, compared to patients with no diabetes. They were more likely topresent with respiratory failure requiring intubation, vasopressors, and corticosteroids. The median time to clearance of MERS-CoV RNA was similar (23 days (Q1, Q3: 17, 36) in patients with diabetes and 21.0 days (Q1, Q3: 10, 33) in patients with no diabetes). Mortality at 90 days was higher in patients with diabetes (78.9% versus 54.7%, p <0.0001). Multivariable regression analysis showed that diabetes was an independent risk factor for 90-day mortality(odds ratio, 2.09; 95% confidence interval, 1.18–3.72).Conclusions: Half of the critically ill patients with MERS have diabetes; which is associated with more severe disease. Diabetes is an independent predictor of mortality among critically patients with MERS

Thermodynamic properties of the two-dimensional S=1/2 Heisenberg antiferromagnet coupled to bond phonons

By applying a quantum Monte Carlo procedure based on the loop algorithm we investigate thermodynamic properties of the two-dimensional antiferromagnetic S=1/2 Heisenberg model coupled to Einstein phonons on the bonds. The temperature dependence of the magnetic susceptibility, mean phonon occupation numbers and the specific heat are discussed in detail. We study the spin correlation function both in the regime of weak and strong spin phonon coupling (coupling constants g=0.1, w=8J and g=2, w=2J, respectively). A finite size scaling analysis of the correlation length indicates that in both cases long range Neel order is established in the ground state.Comment: 10 pages, 13 figure