287 research outputs found

    The Learn@Work Socrates-Minerva Research Project 2005-2007

    Get PDF
    This article offers a summary of the goals, activities, products and evaluation of the Socrates-Minerva research project 2005–2007 – Learn@Work. The partners were four higher education providers: Glasgow-Caledonian University (lead), University of Aalborg, University of Innsbruck, and the Dublin Institute of Technology, with one private partner, ATiT, Brussels. The project aim was to develop and test IT-based materials for induction and support for worker-learners using pilot studies in the partner countries, and the development of usable case studies and theoretical models

    A quasi-steady state mathematical model of an integrated ground source heat pump for building space control

    Full text link
    [EN] This paper is concerned with the development of a mathematical model, capable of describing the quasisteady state performance of an integrated ground source heat pump, which is used for heating and cooling of an institutional building located in a Mediterranean climate. The model is structured on functional basis according to the heat pump vapour compression or primary circuit, a secondary ground loop circuit and a secondary building loop circuit. Heat pump heating and cooling capacities, as well as COP, are considered to be dependent variables and are estimated in the model using performance fitted maps. Independent variables include: compressor speed, circulation pump speeds, ground loop return temperature and building circuit return temperature. The model is validated using data from a full-scale ground source heat pump installation. The validated model is used to examine system capacity and performance sensitivity to different control optimisation strategies, including set-point control of room air temperature, room air bandwidth temperature, building loop return water temperature and building loop return bandwidth temperature.This work was supported under the FP7 programme Advanced ground source heat pump systems for heating and cooling in Mediterranean climates (GROUND-MED FP7-ENERGY-2007-2-TREN-218895)CorberĂĄn Salvador, JM.; Finn, D.; Montagud MontalvĂĄ, CI.; Murphy, F.; Edwards, K. (2011). A quasi-steady state mathematical model of an integrated ground source heat pump for building space control. Energy and Buildings. 43(1):82-92. https://doi.org/10.1016/j.enbuild.2010.08.017S829243

    Nonlinear spinor field in Bianchi type-I Universe filled with viscous fluid: numerical solutions

    Full text link
    We consider a system of nonlinear spinor and a Bianchi type I gravitational fields in presence of viscous fluid. The nonlinear term in the spinor field Lagrangian is chosen to be λF\lambda F, with λ\lambda being a self-coupling constant and FF being a function of the invariants II an JJ constructed from bilinear spinor forms SS and PP. Self-consistent solutions to the spinor and BI gravitational field equations are obtained in terms of τ\tau, where τ\tau is the volume scale of BI universe. System of equations for τ\tau and \ve, where \ve is the energy of the viscous fluid, is deduced. This system is solved numerically for some special cases.Comment: 15 pages, 4 figure

    Nac-mediated repression of the serA promoter of Escherichia coli

    Full text link
    Escherichia coli and related bacteria contain two paralogous PII-like proteins involved in nitrogen regulation, the glnB product, PII, and the glnK product, GlnK. Previous studies have shown that cells lacking both PII and GlnK have a severe growth defect on minimal media, resulting from elevated expression of the Ntr regulon. Here, we show that this growth defect is caused by activity of the nac product, Nac, a LysR-type transcription factor that is part of the Ntr regulon. Cells with elevated Ntr expression that also contain a null mutation in nac displayed growth rates on minimal medium similar to the wild type. When expressed from high-copy plasmids, Nac imparts a growth defect to wild-type cells in an expression level-dependent manner. Neither expression of Nac nor lack thereof significantly affected Ntr gene expression, suggesting that the activity of Nac at one or more promoters outside the Ntr regulon was responsible for its effects. The growth defect of cells lacking both PII and GlnK was also eliminated upon supplementation of minimal medium with serine or glycine for solid medium or with serine or glycine and glutamine for liquid medium. These observations suggest that high Nac expression results in a reduction in serine biosynthesis. ÎČ -Galactosidase activity expressed from a Mu d1 insertion in serA was reduced approximately 10-fold in cells with high Nac expression. We hypothesize that one role of Nac is to limit serine biosynthesis as part of a cellular mechanism to reduce metabolism in a co-ordinated manner when cells become starved for nitrogen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72401/1/j.1365-2958.2002.02994.x.pd

    Plane-symmetric inhomogeneous magnetized viscous fluid universe with a variable Λ\Lambda

    Full text link
    The behavior of magnetic field in plane symmetric inhomogeneous cosmological models for bulk viscous distribution is investigated. The coefficient of bulk viscosity is assumed to be a power function of mass density (Ο=Ο0ρn)(\xi =\xi_{0}\rho^{n}). The values of cosmological constant for these models are found to be small and positive which are supported by the results from recent supernovae Ia observations. Some physical and geometric aspects of the models are also discussed.Comment: 18 pages, LaTex, no figur

    The Self Model and the Conception of Biological Identity in Immunology

    Get PDF
    The self/non-self model, first proposed by F.M. Burnet, has dominated immunology for sixty years now. According to this model, any foreign element will trigger an immune reaction in an organism, whereas endogenous elements will not, in normal circumstances, induce an immune reaction. In this paper we show that the self/non-self model is no longer an appropriate explanation of experimental data in immunology, and that this inadequacy may be rooted in an excessively strong metaphysical conception of biological identity. We suggest that another hypothesis, one based on the notion of continuity, gives a better account of immune phenomena. Finally, we underscore the mapping between this metaphysical deflation from self to continuity in immunology and the philosophical debate between substantialism and empiricism about identity

    Search for varying constants of nature from astronomical observation of molecules

    Full text link
    The status of searches for possible variation in the constants of nature from astronomical observation of molecules is reviewed, focusing on the dimensionless constant representing the proton-electron mass ratio ÎŒ=mp/me\mu=m_p/m_e. The optical detection of H2_2 and CO molecules with large ground-based telescopes (as the ESO-VLT and the Keck telescopes), as well as the detection of H2_2 with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope is discussed in the context of varying constants, and in connection to different theoretical scenarios. Radio astronomy provides an alternative search strategy bearing the advantage that molecules as NH3_3 (ammonia) and CH3_3OH (methanol) can be used, which are much more sensitive to a varying ÎŒ\mu than diatomic molecules. Current constraints are âˆŁÎ”ÎŒ/ÎŒâˆŁ<5×10−6|\Delta\mu/\mu| < 5 \times 10^{-6} for redshift z=2.0−4.2z=2.0-4.2, corresponding to look-back times of 10-12.5 Gyrs, and âˆŁÎ”ÎŒ/ÎŒâˆŁ<1.5×10−7|\Delta\mu/\mu| < 1.5 \times 10^{-7} for z=0.88z=0.88, corresponding to half the age of the Universe (both at 3σ\sigma statistical significance). Existing bottlenecks and prospects for future improvement with novel instrumentation are discussed.Comment: Contribution to Workshop "High Performance Clocks in Space" at the International Space Science Institute, Bern 201

    Obesity treatment—more than food and exercise: a qualitative study exploring obese adolescents' and their parents' views on the former's obesity

    Get PDF
    The aim of this study was to explore obese adolescents’ and their parents’ views on the former's obesity; especially to gain knowledge about barriers and motivational factors that influence obese adolescents’ ability to lose weight. This is a qualitative study involving field observation and semi-structured interviews with obese adolescents and their parents. The analysis takes a phenomenological–hermeneutic approach. Fifteen obese adolescents aged 13–16 years and their parents/grandparents participated in this study (one father, seven mothers, five sets of parents and two sets of grandparents). The results showed that obese adolescents’ are aware that they have unhealthy eating habits and they wish they were able to attain to a healthier diet. Although in poor physical shape, obese adolescents perceive their daily level of exercise as moderate. Obese adolescents blame themselves for being obese and blame their parents for an unhealthy diet, and for being unsupportive regarding exercise. Parents blame their obese child of lacking will power to change eating and exercise habits. As a consequence, the homely atmosphere is often characterised by quarrels and negative feelings. The conclusion is that despite obese adolescents’ intention of reducing weight, underlying issues interfere with this goal. This is particularly related to quarrels with parents, self-blame and misguided understanding of eating and exercising habits. These matters need to be addressed when treating obesity among adolescents
    • 

    corecore