Strain-induced topological phase transition in phosphorene and phosphorene nanoribbons

Using the tight-binding (TB) approximation with inclusion of the spin-orbit interaction, we predict a topological phase transition in the electronic band structure of phosphorene in the presence of axial strains. We derive a low-energy TB Hamiltonian that includes the spin-orbit interaction for bulk phosphorene. Applying a compressive biaxial in-plane strain and perpendicular tensile strain in ranges where the structure is still stable leads to a topological phase transition. We also examine the influence of strain on zigzag phosphorene nanoribbons (zPNRs) and the formation of the corresponding protected edge states when the system is in the topological phase. For zPNRs up to a width of 100 nm the energy gap is at least three orders of magnitude larger than the thermal energy at room temperature.Comment: 10 pages, 6 figure

Health inequalities and development plans in Iran: An analysis of the past three decades (1984–2010)

Introduction: Reducing inequalities in health care is one of the main challenges in all countries. In Iran as in other oil-exporting upper middle income countries, we expected to witness fewer inequalities especially in the health sector with the increase in governmental revenues. Methods: This study presents an inequalities assessment of health care expenditures in Iran. We used data from the Household Income and Expenditure Survey (HIES) in Iran from 1984–2010. The analysis included 308,735 urban and 342,532 rural households. Results: The results suggest heightened inequality in health care expenditures in Iran over the past three decades, including an increase in the gap between urban and rural areas. Furthermore, inflation has affected the poor more than the rich. The Kakwani progressivity index in all years is positive, averaging 0.436 in rural and 0.470 in urban areas during the time period of analysis. Compared to inequality in income distribution over the last 30 years, health expenditures continuously show more inequality and progressivity over the same period of time. Conclusions: According to the result of our study, during this period Iran introduced four National Development Plans (NDPs); however, the NDPs failed to provide sustainable strategies for reducing inequalities in health care expenditures. Policies that protect vulnerable groups should be prioritized

The fatigue in workers of Iran Central Iron Ore Company in Yazd.

AIMS: To evaluate fatigue, sub-dimensions, and job satisfaction among workers of Iran Central Iron Ore Co., and obtain the relationship between them. MATERIALS AND METHODS: In a cross-sectional study, fatigue and the dimensionality were measured using Iranian version of Piper Fatigue Scale questionnaire (PFS). Job satisfaction was estimated with the job satisfaction scale (JSS) as well. RESULTS: The score of severe fatigue in four sub-scale/dimensions and total fatigue scores were: 11.9, 15.2, 11.3, 10.8 and 10.6%, respectively. Furthermore, there was significant difference between total fatigue and all its sub-dimensions in relation to job satisfaction of workers. CONCLUSIONS: Fatigue has caused job dissatisfaction of participants in our study, therefore we should note that the nature of fatigue may affect the psychological aspects of industrial workforce and can be harmful for business activities

Investigation of the effective factors on rate of stemflow for tree species in Hyrcanian forests

The objective of this study was (i) to compare the amount of stemflow in deciduous broadleaved trees (with and without leaves) in accordance with different growth seasons and (ii) to compare the rate of stemflow in coniferous and broadleaved trees in according to the canopy cover area. Stemflow was measured on 20 marked trees using a stemflow collector. Rates were different for the different tree species Beech Fagus orientalis L, Ironwood Parrotia persica L., Alder Alnus subcordata L. and Hornbeam Carpinus betulus L., and were greater in autumn than winter even though trees were then in leaf. The stemflow increased with increasing canopy cover area. Even though canopy cover in conifers (Cupressus sempervirens var. horizontalis) was less than the broad-leaved beech, the rate of stemflow was higher, up to 7 litres per hour with relatively small canopies.Keywords: canopy, seasons, conifers, broad-leaved tree

Development of Production Scheduling Model With Constraint Resources and Parallel Machines

In this paper, a production scheduling model with constraint resources and parallel machines has been investigated. This problem is proposed as a multi-product production problem. Shortage is not allowed and the production horizon is indefinite. The objective is to maximize the level of resource usage and support the management’s standpoint (delays reduction). In this paper, this problem is modeled as the popular Knapsack problem in 0 and 1 programming. Then due to being NP-hard type for this kind of problems to obtain an optimal solution, A heuristic approach has been used to obtain the acceptable solution. By using the branch-and bound method, a near optimal solution is provided. Finally, resultant solutions by the proposed approach have been compared with the optimal solutions of some real-world problems and it has been observed that deviation from the optimal solution is negligible that indicates the accuracy of the proposed approach

Antioxidant and antihemolytic activities of methanol extract of Hyssopus angustifolius

This study was designed to evaluate antioxidant and antihemolytic activities of Hyssopus angustifolius flower, stem and leaf methanol extracts by employing various in vitro assays. The leaf extract showed the best activity in DPPH (63.2 ± 2.3 μg mL-1) and H2O2  (55.6 ± 2.6 μg mL-1) models compared to the other extracts. However, flower extract exhibited the highest Fe2+ chelating activity (131.4 ± 4.4 μg mL-1). The extracts exhibited good antioxidant activity in linoleic acid peroxidation and reducing power assays, but were not comparable to vitamin C. The stem (23.58 ± 0.7 μg mL-1) and leaf (26.21 ± 1 μg mL-1) extracts showed highest level of antihemolytic activity than the flower extract

Effects of sub-lethal concentrations of Euphorbia turcomanica extract on some liver biochemical parameters of Zebra Aphanius (Aphanius dispar)

In the present study, effects of sub-lethal concentrations of Euphorbia turcomanica extract with ranging from 0.00, 0.0055 (5% of LC50), 0.011 (10% of LC50) and 0.022 (20% of LC50) g/lit were investigated over 30 days on biochemical parameters of Zebra Aphanius (Aphanius dispar). The average (±SE) 24, 48, 72 and 96 LC50 rates of E. turcomanica on fish were 0.28±0.14, 0.19±0.06, 0.14±0.03 and 0.11±0.02 g/lit, respectively. The biochemical parameters including aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), creatine phosphokinase (CK), and alkaline phosphatase (ALP) activities in the liver tissue were measured after 15 and 30 days. Significant changes in AST, ALT, ALP, LDH and CK activities were observed in fish exposed to different concentrations of E. turcomanica extract when compared with control group. The significant increase was determined in AST, LDH and ALP while in ALT and CK, significant decrease was revealed. Also in liver total protein, a significant descending trend related to exposure time was demonstrated. In conclusion, the findings from this study provide basic information about toxicity of E. turcomanica extract on Zabra Aphanius, as well as developing guidelines for evaluating the effects of administration of E. turcomanica derivatives in water