Constructing a neutron star in G2-QCD

The inner structure of neutron stars is still an open question. To make progress and understand the qualitative impact of gauge interactions on the neutron star structure we study neutron stars in a modified version of QCD. In this modification the gauge group of QCD is replaced by the exceptional Lie group G$_2$, which has neutrons and is accessible at finite density in lattice calculations. Using an equation of state constructed from lattice calculations we determine the mass-radius-relation for a neutron star in this theory using the Tolman-Oppenheimer-Volkoff equation. The results exhibit an influence of the non-trivial interactions on the mass-radius relation. However, the masses of the quarks are found to have little influence. We also give density profiles and the phase structure inside the neutron star. If the results carry over to full QCD, much of the internal structure of neutron stars could already be inferred from a precise measurement of the mass-radius relation.Comment: (23 pages, 32 figures), Improved presentation, version to appear in European Physical Journal

Equity of health care financing in Iran

This study presents the rst analyses of the equity of health care financing in Iran. Kakwani Progressivity Indices (KPIs) and concentration indices (CIs) are estimated using ten national household expenditure surveys, which were conducted in Iran from 1995/96 to 2004/05. The indices are used to analyze the progressivity of two sources of health care financing: health insurance premium payments and consumer co-payments (and the sum of these), for Iran as a whole, and for rural and urban areas of Iran, separately. The results suggest that health insurance premium payments became more progressive over the study period; however the KPIs for consumer co-payments suggest that these are still mildly regressive or slightly progressive, depending upon whether household income or expenditure data are used to generate the indices. Interestingly, the Urban Inpatient Insurance Scheme (UIIS), which was introduced by the Iranian government in 2000 to extend insurance to uninsured urban dwellers, appears to have had a regressive impact on health care nancing, which is contrary to expectations. This result sounds a cautionary note about the potential for public programs to crowd out private sector, charitable activity, which was prevalent in Iran prior to the introduction of the UIIS.Equity, Health care nancing, Kakwani progressivity index, Iran

Modeling of influential predictors of gastric cancer incidence rates in Golestan Province, North Iran

Golestan province has a reputation for relatively high incidence rates of gastric cancer in Iran. Along with dietary, lifestyle and environmental influential factors, soil selenium and high levels of pesticide used may exert influence in this region. The present study was designed for modeling the influential predictors on incidence of gastric cancer in Golestan. All registered cases of gastric cancer from March 2009 to March 2010 (49 females and 107 males) were investigated. Data were gathered by both check list and researcher made questionnaire (demographic, clinical and lifestyle characteristics) and analysed using logistic regression. Mean (±SD) age at diagnosis was 62.9±13.8 years. CIR and ASR of gastric cancer showed 9.16 and 13.9 per 100,000 people, respectively. Based on univariate logistic regression, a history of smoking (OR= 2.076), unwashed hands after defecation (OR= 2.612), history of cancer in relatives (OR= 2.473), history of gastric cancer in first-degree relatives (OR= 2.278), numbers of gastric cancers in first-degree relatives (OR= 2.078), history of X-ray and dye exposure (OR= 2.395), history of CT scan encounter (OR= 2.915), improper food habits (OR= 3.320), specific eating behavior (OR= 0.740), consumption of probable high risk foods (OR= 2.942), charred flesh (OR= 1.945), and animal fat (OR= 2.716) were confirmed as a risk factors. Changes in lifestyle may be expected to increase gastric cancer incidence dramatically in the near future. Therefore, appropriate educational interventions should be designed and implemented by competent authorities

Gluon and ghost correlation functions of 2-color QCD at finite density

2-color QCD, i. e. QCD with the gauge group SU(2), is the simplest non-Abelian gauge theory without sign problem at finite quark density. Therefore its study on the lattice is a benchmark for other non-perturbative approaches at finite density. To provide such benchmarks we determine the minimal-Landau-gauge 2-point and 3-gluon correlation functions of the gauge sector and the running gauge coupling at finite density. We observe no significant effects, except for some low-momentum screening of the gluons at and above the supposed high-density phase transition.Comment: 7 pages, 10 figures, talk presented at the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spai

Back-to-back Converter Control of Grid-connected Wind Turbine to Mitigate Voltage Drop Caused by Faults

Power electronic converters enable wind turbines, operating at variable speed, to generate electricity more efficiently. Among variable speed operating turbine generators, permanent magnetic synchronous generator (PMSG) has got more attentions due to low cost and maintenance requirements. In addition, the converter in a wind turbine with PMSG decouples the turbine from the power grid, which favors them for grid codes. In this paper, the performance of back-to-back (B2B) converter control of a wind turbine system with PMSG is investigated on a faulty grid. The switching strategy of the grid side converter is designed to improve voltage drop caused by the fault in the grid while the maximum available active power of wind turbine system is injected to the grid and the DC link voltage in the converter is regulated. The methodology of the converter control is elaborated in details and its performance on a sample faulty grid is assessed through simulation