72 research outputs found
Calculating the cost of work-related stress and psychosocial risks
Work-related stress is expensive. Tackling stress and psychosocial risks can be viewed as too costly, but the reality is that it costs more to ignore them. Stress affects performance and leads to absence from work. If prolonged it may result in serious health problems such as cardiovascular or musculoskeletal diseases. All this comes at a cost. This report summarises the studies focusing on calculating costs of work-related stress and psychosocial risks. The main costs for individuals relate to health impairment, lower income and reduced quality of life. Organisations are affected by costs related to absenteeism, presenteeism, reduced productivity or high staff turnover. Health care costs and poorer business outcomes ultimately affect national economies and society
The R-map and the Coupling of N=2 Tensor Multiplets in 5 and 4 Dimensions
We study the dimensional reduction of five dimensional N=2
Yang-Mills-Einstein supergravity theories (YMESGT) coupled to tensor
multiplets. The resulting 4D theories involve first order interactions among
tensor and vector fields with mass terms. If the 5D gauge group, K, does not
mix the 5D tensor and vector fields, the 4D tensor fields can be integrated out
in favor of 4D vector fields and the resulting theory is dual to a standard 4D
YMESGT. The gauge group has a block diagonal symplectic embedding and is a
semi-direct product of the 5D gauge group K with a Heisenberg group of
dimension (2P+1), where 2P is the number of tensor fields in five dimensions.
There exists an infinite family of theories, thus obtained, whose gauge groups
are pp-wave contractions of the simple noncompact groups of type SO*(2M). If,
on the other hand, the 5D gauge group does mix the 5D tensor and vector fields,
the resulting 4D theory is dual to a 4D YMESGT whose gauge group does, in
general,NOT have a block diagonal symplectic embedding and involves additional
topological terms. The scalar potentials of the dimensionally reduced theories
naturally have some of the ingredients that were found necessary for stable de
Sitter ground states. We comment on the relation between the known 5D and 4D,
N=2 supergravities with stable de Sitter ground states.Comment: 42 pages;latex fil
Scaling Cosmologies of N=8 Gauged Supergravity
We construct exact cosmological scaling solutions in N=8 gauged supergravity.
We restrict to solutions for which the scalar fields trace out geodesic curves
on the scalar manifold. Under these restrictions it is shown that the axionic
scalars are necessarily constant. The potential is then a sum of exponentials
and has a very specific form that allows for scaling solutions. The scaling
solutions describe eternal accelerating and decelerating power-law universes,
which are all unstable. An uplift of the solutions to 11-dimensional
supergravity is carried out and the resulting timedependent geometries are
discussed. In the discussion we briefly comment on the fact that N=2 gauged
supergravity allows stable scaling solutions.Comment: 17 pages; referenced added, reportnr changed and some corrections in
section
Turnover, account value and diversification of real traders: evidence of collective portfolio optimizing behavior
Despite the availability of very detailed data on financial market,
agent-based modeling is hindered by the lack of information about real trader
behavior. This makes it impossible to validate agent-based models, which are
thus reverse-engineering attempts. This work is a contribution to the building
of a set of stylized facts about the traders themselves. Using the client
database of Swissquote Bank SA, the largest on-line Swiss broker, we find
empirical relationships between turnover, account values and the number of
assets in which a trader is invested. A theory based on simple mean-variance
portfolio optimization that crucially includes variable transaction costs is
able to reproduce faithfully the observed behaviors. We finally argue that our
results bring into light the collective ability of a population to construct a
mean-variance portfolio that takes into account the structure of transaction
costsComment: 26 pages, 9 figures, Fig. 8 fixe
Stable de Sitter vacua in N=2, D=5 supergravity
We find 5D gauged supergravity theories exhibiting stable de Sitter vacua.
These are the first examples of stable de Sitter vacua in higher-dimensional
(D>4) supergravity. Non-compact gaugings with tensor multiplets and R-symmetry
gauging seem to be the essential ingredients in these models. They are however
not sufficient to guarantee stable de Sitter vacua, as we show by investigating
several other models. The qualitative behaviour of the potential also seems to
depend crucially on the geometry of the scalar manifold.Comment: 26 pages, v2:typos corrected, published versio
Null Deformed Domain Wall
We study null 1/4 BPS deformations of flat domain wall solutions (NDDW) in
N=2, d=5 gauged supergravity with hypermultiplets and vector multiplets
coupled. These are uncharged time-dependent configurations and contain as
special case, 1/2 supersymmetric flat domain walls (DW), as well as 1/2 BPS
null solutions of the ungauged supergravity. Combining our analysis with the
classification method initiated by Gauntlett et al., we prove that all the
possible deformations of the DW have origin in the hypermultiplet sector or/and
are null. Here, we classify all the null deformations: we show that they
naturally organize themselves into "gauging" (v-deformation) and "non gauging"
(u-deformation). They have different properties: only in presence of
v-deformation is the solution supported by a time-dependent scalar potential.
Furthermore we show that the number of possible deformations equals the number
of matter multiplets coupled. We discuss the general procedure for constructing
explicit solutions, stressing the crucial role taken by the integrability
conditions of the scalars as spacetime functions. Two analytical solutions are
presented. Finally, we comment on the holographic applications of the NDDW, in
relation to the recently proposed time-dependent AdS/CFT.Comment: 38 pages; minor changes, references added; text revised, minor
changes, final version published in JHE
Potentiation of thrombus instability: a contributory mechanism to the effectiveness of antithrombotic medications
© The Author(s) 2018The stability of an arterial thrombus, determined by its structure and ability to resist endogenous fibrinolysis, is a major determinant of the extent of infarction that results from coronary or cerebrovascular thrombosis. There is ample evidence from both laboratory and clinical studies to suggest that in addition to inhibiting platelet aggregation, antithrombotic medications have shear-dependent effects, potentiating thrombus fragility and/or enhancing endogenous fibrinolysis. Such shear-dependent effects, potentiating the fragility of the growing thrombus and/or enhancing endogenous thrombolytic activity, likely contribute to the clinical effectiveness of such medications. It is not clear how much these effects relate to the measured inhibition of platelet aggregation in response to specific agonists. These effects are observable only with techniques that subject the growing thrombus to arterial flow and shear conditions. The effects of antithrombotic medications on thrombus stability and ways of assessing this are reviewed herein, and it is proposed that thrombus stability could become a new target for pharmacological intervention.Peer reviewedFinal Published versio
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