288 research outputs found
The Learn@Work Socrates-Minerva Research Project 2005-2007
This article offers a summary of the goals, activities, products and evaluation of the Socrates-Minerva research project 2005â2007 â 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
[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
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 , with being a self-coupling
constant and being a function of the invariants an constructed from
bilinear spinor forms and . Self-consistent solutions to the spinor and
BI gravitational field equations are obtained in terms of , where
is the volume scale of BI universe. System of equations for 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
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
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 . 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
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
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
. The optical detection of H and CO molecules with large
ground-based telescopes (as the ESO-VLT and the Keck telescopes), as well as
the detection of H 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 NH
(ammonia) and CHOH (methanol) can be used, which are much more sensitive to
a varying than diatomic molecules. Current constraints are
for redshift , corresponding to
look-back times of 10-12.5 Gyrs, and for
, corresponding to half the age of the Universe (both at 3
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 treatmentâmore than food and exercise: a qualitative study exploring obese adolescents' and their parents' views on the former's obesity
The aim of this study was to explore obese adolescentsâ and their parentsâ views on the former's obesity; especially to gain knowledge about barriers and motivational factors that influence obese adolescentsâ 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 phenomenologicalâhermeneutic approach. Fifteen obese adolescents aged 13â16 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 adolescentsâ 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 adolescentsâ 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
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