Offshore wind power integration to support weak grid voltage for industrial loads using VSC-HVDC transmission system

This paper investigates the integration of the offshore wind power plant into the grid using voltage source converter high-voltage direct current (VSC-HVDC). The paper proposes both offshore and onshore converter stations control to support voltage variation in grid. Heavy industrial loads result in a weak grid. In this paper, the effect on industrial loads by the grid strength is shown. Then the paper proposes a solution for the grid voltage support for industrial loads connected to weak grids. The results showed that the increase of grid voltage from 0.7 pu to 1 pu at full load condition that provides a continuous operation without any interruption. The system was modelled using MATLAB/Simulink package

The potential for measuring ethnicity and health in a multicultural milieu - the case of type 2 diabetes in Australia

ObjectiveEthnicity influences health in many ways. For example, type 2&nbsp;diabetes (T2DM) is disproportionately prevalent among certain ethnic groups.&nbsp;Assessing ethnicity is difficult, and numerous proxy measures are used to&nbsp;capture its various components. Australian guidelines specify a set of&nbsp;variables for measuring ethnicity, and how such parameters should be&nbsp;categorised. Using T2DM data collections as an illustrative example, this&nbsp;study sought to examine how ethnicity is measured in Australian health&nbsp;databases and, by comparing current practice with Australia&rsquo;s existing&nbsp;benchmark recommendations, to identify potential areas for improvement of&nbsp;the health data landscape.DesignWe identified databases containing information from which ethnic&nbsp;group-specific estimates of T2DM burden may be gleaned. For each&nbsp;database, details regarding ethnicity variables were extracted, and compared&nbsp;with the Australian guidelines.&nbsp;ResultsData collection instruments for 32 relevant databases were reviewed.&nbsp;Birthplace was recorded in 27 databases (84%), but mode of birthplace&nbsp;assessment varied. Indigenous status was commonly recorded (78%, n=25), but&nbsp;only nine databases recorded other aspects of self-perceived race/ethnicity. Of&nbsp;28 survey/audit databases, 14 accommodated linguistic preferences other than&nbsp;English, and 11 either excluded non-English speakers or those for whom a&nbsp;translator was not available, or only offered questionnaires in English.ConclusionsConsiderable variation exists in the measurement of ethnicity in&nbsp;Australian health data- sets. While various markers of ethnicity provide&nbsp;complementary information about the ethnic profile within a data-set, nonuniform&nbsp;measurement renders comparison between data-sets difficult. A&nbsp;standardised approach is necessary, and identifying the ethnicity variables&nbsp;that are particularly relevant to the health sector is warranted. Including self identified&nbsp;ethnicity in Australia&rsquo;s set of recommended indicators and as a core&nbsp;component of the national census should be considered. Globalisation and&nbsp;increasing migration mean that these findings have implications internationally,&nbsp;including for multi-ethnic countries throughout North America and&nbsp;Europe.</div

Thrombophilia gene mutations in relation to recurrent miscarriage

Background: Recurrent pregnancy loss is multifactorial involving clinical and biological risk factors. Evidence addressed the association of inherited thrombophilia with recurrent pregnancy loss and other serious pregnancy complications. However, the relation between thrombophilia associated gene mutations and adverse obstetric outcome is controversial and data in the literature are inconsistent. The aim of this study was to investigate the prevalence of thrombophilia associated gene mutations (factor V Leiden, prothrombin gene G20210A and methylene-tetrahydrofolate reductase MTHFR C677T) in relation to recurrent miscarriage.Methods: Case control study conducted on 200 women recruited from Elshatby Maternity Hospital clinics. The cases group included 100 women with history of three or more unexplained consecutive pregnancy losses, while 100 healthy age matched women with no history of recurrent miscarriages served as controls. Blood samples were collected from all women enrolled in the study for DNA extraction and genotype analysis. Factor V, prothrombin and MTHFR gene mutations were assayed based on polymerase chain reaction (PCR) and reverse-hybridization.Results: The prevalence of Factor V Leiden and prothrombin gene G20210A mutations did not differ significantly between cases and controls. However, MTHFR C667T mutations and the total prevalence of the three gene mutations were significantly increased in the patients group compared to controls (p=0.001, p=0.003 respectively). The prevalence of combined thrombophilia of Factor V Leiden and MTHFR C677T was significantly increased in the patients group compared to controls (p=0.032). Regarding homozygosity of each of the gene mutations, no homozygosity was detected in controls and heterozygotes were significantly increased in the patients group compared to homozygotes.Conclusions: MTHFR mutations and the total prevalence of the three gene mutations were significantly increased in the patients group compared to controls. There was a significant increase in the prevalence of combined thrombophilia (Factor V Leiden and MTHFR C677T) in the patients group compared to controls without involvement of prothrombin gene

Perceptions of Assistant Principals’ and Principals’ of Bahrain Government Schools about the Impact of the Bahrain Teachers College Educational Leadership Program on Their Performance

This article examines the perceptions of school assistant principals and principals who completed the Bahrain Teachers College higher diploma of education leadership program about its impact on their performance. The study sample consisted of 141 program graduates from 9- cohorts. A multilevel concept in measuring the impact of the educational leadership program on the graduates’ performance was employed. The framework consisted of 4 levels: self-learning, changing others, embedding changes in school practices and sustainability of change and scaling up the school performance. The study questionnaire was designed on the basis of this framework. Results show that the Educational Leadership program positively affected its graduates’ performance in the 4 levels. The majority of the program graduates agreed that the program positively affected their personal qualities, leadership styles and practices to support school development, school staff, students’ performance and school ranking. The majority of the program graduates also agreed that the program positively affected their skills in dealing with curriculum innovations, professional development, research, strategic planning, staff appraisal, communication with community, using ICT, improving students’ learning and applying educational ethics. &nbsp; &nbsp; Keywords: Education Leadership, School Principals’ Performance, Leadership Styles, School Practices, Leadership Skill

Measurement of the bb dijet cross section in pp collisions at √s = 7 TeV with the ATLAS detector

Funded by SCOAP3The dijet production cross section for jets containing a b-hadron (b-jets) has been measured in proton–proton collisions with a centre-of-mass energy of √s = 7 TeV, using the ATLAS detector at the LHC. The data used correspond to an integrated luminosity of 4.2 fb−1. The cross section is measured for events with two identified b-jets with a transverse momentum pT > 20 GeV and a minimum separation in the η–φ plane of R = 0.4. At least one of the jets in the event is required to have pT > 270 GeV. The cross section is measured differentially as a function of dijet invariant mass, dijet transverse momentum, boost of the dijet system, and the rapidity difference, azimuthal angle and angular distance between the b-jets. The results are compared to different predictions of leading order and next-to-leading order perturbative quantum chromodynamics matrix elements supplemented with models for parton-showers and hadronization

An effective scalable SQL engine for NoSQL databases

NoSQL databases were initially devised to support a few concrete extreme scale applications. Since the specificity and scale of the target systems justified the investment of manually crafting application code their limited query and indexing capabilities were not a major im- pediment. However, with a considerable number of mature alternatives now available there is an increasing willingness to use NoSQL databases in a wider and more diverse spectrum of applications and, to most of them, hand-crafted query code is not an enticing trade-off. In this paper we address this shortcoming of current NoSQL databases with an effective approach for executing SQL queries while preserving their scalability and schema flexibility. We show how a full-fledged SQL engine can be integrated atop of HBase leading to an ANSI SQL compli- ant database. Under a standard TPC-C workload our prototype scales linearly with the number of nodes in the system and outperforms a NoSQL TPC-C implementation optimized for HBase.(undefined

Vacuum Stability of the wrong sign (−ϕ6)(-\phi^{6}) Scalar Field Theory

We apply the effective potential method to study the vacuum stability of the bounded from above $(-\phi^{6})$ (unstable) quantum field potential. The stability ($\partial E/\partial b=0)$ and the mass renormalization ($\partial^{2} E/\partial b^{2}=M^{2})$ conditions force the effective potential of this theory to be bounded from below (stable). Since bounded from below potentials are always associated with localized wave functions, the algorithm we use replaces the boundary condition applied to the wave functions in the complex contour method by two stability conditions on the effective potential obtained. To test the validity of our calculations, we show that our variational predictions can reproduce exactly the results in the literature for the $\mathcal{PT}$-symmetric $\phi^{4}$ theory. We then extend the applications of the algorithm to the unstudied stability problem of the bounded from above $(-\phi^{6})$ scalar field theory where classical analysis prohibits the existence of a stable spectrum. Concerning this, we calculated the effective potential up to first order in the couplings in $d$ space-time dimensions. We find that a Hermitian effective theory is instable while a non-Hermitian but $\mathcal{PT}$-symmetric effective theory characterized by a pure imaginary vacuum condensate is stable (bounded from below) which is against the classical predictions of the instability of the theory. We assert that the work presented here represents the first calculations that advocates the stability of the $(-\phi^{6})$ scalar potential.Comment: 21pages, 12 figures. In this version, we updated the text and added some figure

Physical properties of thermoelectric zinc antimonide using first-principles calculations

We report first principles calculations of the structural, electronic, elastic and vibrational properties of the semiconducting orthorhombic ZnSb compound. We study also the intrinsic point defects in order to eventually improve the thermoelectric properties of this already very promising thermoelectric material. Concerning the electronic properties, in addition to the band structure, we show that the Zn (Sb) crystallographically equivalent atoms are not exactly equivalent from the electronic point of view. Lattice dynamics, elastic and thermodynamic properties are found to be in good agreement with experiments and they confirm the non equivalency of the zinc and antimony atoms from the vibrational point of view. The calculated elastic properties show a relatively weak anisotropy and the hardest direction is the y direction. We observe the presence of low energy modes involving both Zn and Sb atoms at about 5-6 meV, similarly to what has been found in Zn4Sb3 and we suggest that the interactions of these modes with acoustic phonons could explain the relatively low thermal conductivity of ZnSb. Zinc vacancies are the most stable defects and this explains the intrinsic p-type conductivity of ZnSb.Comment: 33 pages, 8 figure