1,046 research outputs found

    A systematic approach for the implementation of an effective management model for gland service

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    Abstract:The aim of the research was to develop an Effective Management Model (EMM) for a Gland Service System (GSS). The Systematic Approach to Engineering Design focuses on the optimisation of the GSS which is a fundamental pillar for the functionality of the slurry pumps in a tailings plant. The EMM was considered for a wide variety of mining applications to innovatively create a method for the correct design, implementation, control and maintenance of a Gland Service System. A Production Performance Model (PPM) was created utilising the Overall Equipment Effectiveness (OEE) Theory to provide an indication of the production capacity of a tailings plant. The subsystem of the PPM was the EMM, its core focus was on the optimisation of the Gland Service System, which in turn directly relates the improved performance of the tailings plant which ultimately results in the improved capability of the mines production process. Simulink was used to incorporate the optimisation inputs of the GSS, thus forming a model from Qualitative and Quantitative feedback as well as the Experimentation with regard to water quality and its effect on the GSS. By using these data sets, triangulation of the data sampling systems was used. The combination of non-probability sampling, and purpose sampling systems formed the basis of the triangulation system

    On the accretion disc properties in eclipsing dwarf nova EM Cyg

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    In this paper we analyzed the behavior of the unusual dwarf nova EM Cyg using the data obtained in April-October, 2007 in Vyhorlat observatory (Slovak Republic) and in September, 2006 in Crimean Astrophysical Observatory (Ukraine). During our observations EM Cyg has shown outbursts in every 15-40 days. Because on the light curves of EM Cyg the partial eclipse of an accretion disc is observed we applied the eclipse mapping technique to reconstruct the temperature distribution in eclipsed parts of the disc. Calculations of the accretion rate in the system were made for the quiescent and the outburst states of activity for different distances.Comment: 6 pages, 3 figures, accepted in Astrophysics and Space Scienc

    The reaction of cytochrome c with [Fe(EDTA)(H2O)]−

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    AbstractThe interaction of horse ferricytochrome c with the reagents [Fe(EDTA)(H2O)]− and [Cr(CN)6]3− were studied at pH 7 and 25°C by 1H-NMR spectroscopy. Two binding regions near to the heme crevice of cytochrome c were identified. Both regions bound both reagents but they exhibited different selectivities.The relevance of this finding to the electron-transfer function of cytochrome c is discussed

    Risk-adjusted survival for adults following in-hospital cardiac arrest by day of week and time of day: Observational cohort study

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    Background: Internationally, hospital survival is lower for patients admitted at weekends and at night. Data from the UK National Cardiac Arrest Audit (NCAA) indicate that crude hospital survival was worse after in-hospital cardiac arrest (IHCA) at night versus day, and at weekends versus weekdays, despite similar frequency of events. Objective: To describe IHCA demographics during three day/time periods - weekday daytime (Monday to Friday, 08:00 to 19:59), weekend daytime (Saturday and Sunday, 08:00 to 19:59) and night-time (Monday to Sunday, 20:00 to 07:59) - and to compare the associated rates of return of spontaneous circulation (ROSC) for >20 min (ROSC>20 min) and survival to hospital discharge, adjusted for risk using previously developed NCAA risk models. To consider whether any observed difference could be attributed to differences in the case mix of patients resident in hospital and/or the administered care. Methods: We performed a prospectively defined analysis of NCAA data from 27 700 patients aged ≄16 years receiving chest compressions and/or defibrillation and attended by a hospital-based resuscitation team in response to a resuscitation (2222) call in 146 UK acute hospitals. Results: Risk-adjusted outcomes (OR (95% CI)) were worse (p20 min 0.88 (0.81 to 0.95); hospital survival 0.72 (0.64 to 0.80)), and nighttime (ROSC>20 min 0.72 (0.68 to 0.76); hospital survival 0.58 (0.54 to 0.63)) compared with weekday daytime. The effects were stronger for non-shockable than shockable rhythms, but there was no significant interaction between day/ time of arrest and age, or day/time of arrest and arrest location. While many daytime IHCAs involved procedures, restricting the analyses to IHCAs in medical admissions with an arrest location of ward produced results that are broadly in line with the primary analyses. Conclusions: IHCAs attended by the hospital-based resuscitation team during nights and weekends have substantially worse outcomes than during weekday daytimes. Organisational or care differences at night and weekends, rather than patient case mix, appear to be responsible

    Prevalence of sexual harassment among Norwegian female elite athletes in relation to sport type

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    Although it is often assumed that the prevalence of sexual harassment is different in different sports, this assumption has not been empirically tested. This study considers whether the experience of sexual harassment varies by sport. The female elite athletes (N = 553) in the study participated in 56 different sport disciplines. These were grouped as follows :1) team or individual sports; 2) extent to which clothing required for competition is revealing ; 3) gender structure (male-or female dominated membership statistics); and 4) gender culture (masculine, gender-neutral, or feminine). The data show that sexual harassment occurs in every sport group. Female elite athletes who participated in ‘masculine’ sports appear to experience more harassment than women in the other groups. We conclude that, when it comes to female athletes’ experiences of sexual harassment, sport type matters far less than sport participation per se

    MYCN expression induces replication stress and sensitivity to PARP inhibition in neuroblastoma

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    This study investigates the influence expression of the MYCN oncogene has on the DNA damage response, replication fork progression and sensitivity to PARP inhibition in neuroblastoma. In a panel of neuroblastoma cell lines, MYCN amplification or MYCN expression resulted in increased cell death in response to a range of PARP inhibitors (niraparib, veliparib, talazoparib and olaparib) compared to the response seen in non-expressing/amplified cells. MYCN expression slowed replication fork speed and increased replication fork stalling, an effect that was amplified by PARP inhibition or PARP1 depletion. Increased DNA damage seen was specifically induced in S-phase cells. Importantly, PARP inhibition caused a significant increase in the survival of mice bearing MYCN expressing tumours in a transgenic murine model of MYCN expressing neuroblastoma. Olaparib also sensitized MYCN expressing cells to camptothecin- and temozolomide-induced cell death to a greater degree than non-expressing cells. In summary, MYCN expression leads to increased replication stress in neuroblastoma cells. This effect is exaggerated by inhibition of PARP, resulting in S-phase specific DNA damage and ultimately increased tumour cell death. PARP inhibition alone or in combination with classical chemotherapeutics is therefore a potential therapeutic strategy for neuroblastoma and may be more effective in MYCN expressing tumours

    Sub-microsecond correlations in photoluminescence from InAs quantum dots

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    Photon correlation measurements reveal memory effects in the optical emission of single InAs quantum dots with timescales from 10 to 800 ns. With above-band optical excitation, a long-timescale negative correlation (antibunching) is observed, while with quasi-resonant excitation, a positive correlation (blinking) is observed. A simple model based on long-lived charged states is presented that approximately explains the observed behavior, providing insight into the excitation process. Such memory effects can limit the internal efficiency of light emitters based on single quantum dots, and could also be problematic for proposed quantum-computation schemes.Comment: 8 pages, 8 figure

    Fluorescence spectrum of a two-level atom driven by a multiple modulated field

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    We investigate the fluorescence spectrum of a two-level atom driven by a multiple amplitude-modulated field. The driving held is modeled as a polychromatic field composed of a strong central (resonant) component and a large number of symmetrically detuned sideband fields displaced from the central component by integer multiples of a constant detuning. Spectra obtained here differ qualitatively from those observed for a single pair of modulating fields [B. Blind, P.R. Fontana, and P. Thomann, J. Phys. B 13, 2717 (1980)]. In the case of a small number of the modulating fields, a multipeaked spectrum is obtained with the spectral features located at fixed frequencies that are independent of the number of modulating fields and their Rabi frequencies. As the number of the modulating fields increases, the spectrum ultimately evolves to the well-known Mellow triplet with the sidebands shifted from the central component by an effective Rabi frequency whose magnitude depends on the initial relative phases of the components of the driving held. For equal relative phases, the effective Rabi frequency of the driving field can be reduced to zero resulting in the disappearance of fluorescence spectrum, i.e., the atom can stop interacting with the field. When the central component and the modulating fields are 180 degrees out of phase, the spectrum retains its triplet structure with the sidebands located at frequencies equal to the sum of the Rabi frequencies of the component of the driving field. Moreover, we shaw that the frequency of spontaneous emission can be controlled and switched from one frequency to another when the Rabi frequency or initial phase of the modulating fields are varied

    Experiences and Outcomes of Preschool Physical Education: an analysis of developmental discourses in Scottish curricular documentation

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    This article provides an analysis of developmental discourses underpinning preschool physical education in Scotland's Curriculum for Excellence. Implementing a post-structural perspective, the article examines the preschool experiences and outcomes related to physical education as presented in the Curriculum for Excellence ‘health and wellbeing’ documentation. The article interrogates the ways in which developmental discourses are evident throughout this and related documentation and how these discourses might ‘work’ to produce specific effects on practitioners and children as they are deployed and taken up in Scottish preschool education contexts. This analysis involves speculating about potential consequences for practitioners' and children's experiences and subjectivities. In conclusion, it is suggested that practitioners should critically engage with the curriculum, as uncritical acceptance of the discourses underpinning it could lead to practices that may have negative consequences. Furthermore, the article proposes that future research should investigate the ways in which the discourses privileged in the Curriculum for Excellence ‘health and wellbeing’ documentation are taken up and negotiated in Scottish preschool settings
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