21 research outputs found
Spacetime-Filling Branes and Strings with Sixteen Supercharges
We discuss branes whose worldvolume dimension equals the target spacetime
dimension, i.e. ``spacetime-filling branes''. In addition to the D9-branes,
there are 9-branes in the NS-NS sectors of both the IIA and IIB strings. The
worldvolume actions of these branes are constructed, via duality, from the
known actions of branes with codimension larger than zero. Each of these types
of branes is used in the construction of a string theory with sixteen
supercharges by modding out a type II string by an appropriate discrete
symmetry and adding 32 9-branes. These constructions are related by a web of
dualities and each arises as a different limit of the Horava-Witten
construction.Comment: 43 pages, LaTeX, 8 figures, uses html.sty, version to appear in Nucl.
Phys.
Multifocaal toezicht. Professionalisering van intern en extern toezicht door de ogen van Henk Kesler
Market structure and hospital–insurer bargaining in the Netherlands
In 2005, competition was introduced in part of the hospital market in the Netherlands. Using a unique dataset of transactions and list prices between hospitals and insurers in the years 2005 and 2006, we estimate the influence of buyer and seller concentration on the negotiated prices. First, we use a traditional structure–conduct–performance model (SCP-model) along the lines of Melnick et al. (J Health Econ 11(3): 217–233, 1992) to estimate the effects of buyer and seller concentration on price–cost margins. Second, we model the interaction between hospitals and insurers in the context of a generalized bargaining model similar to Brooks et al. (J Health Econ 16: 417–434, 1997). In the SCP-model, we find that the market shares of hospitals (insurers) have a significantly positive (negative) impact on the hospital price–cost margin. In the bargaining model, we find a significant negative effect of insurer concentration, but no significant effect of hospital concentration. In both models, we find a significant impact of idiosyncratic effects on the market outcomes. This is consistent with the fact that the Dutch hospital sector is not yet in a long-run equilibrium
Superconformal N=2, D=5 matter with and without actions
We investigate N=2, D=5 supersymmetry and matter-coupled supergravity
theories in a superconformal context. In a first stage we do not require the
existence of a Lagrangian. Under this assumption, we already find at the level
of rigid supersymmetry, i.e. before coupling to conformal supergravity, more
general matter couplings than have been considered in the literature. For
instance, we construct new vector-tensor multiplet couplings, theories with an
odd number of tensor multiplets, and hypermultiplets whose scalar manifold
geometry is not hyperkaehler.
Next, we construct rigid superconformal Lagrangians. This requires some extra
ingredients that are not available for all dynamical systems. However, for the
generalizations with tensor multiplets mentioned above, we find corresponding
new actions and scalar potentials. Finally, we extend the supersymmetry to
local superconformal symmetry, making use of the Weyl multiplet. Throughout the
paper, we will indicate the various geometrical concepts that arise, and as an
application we compute the non-vanishing components of the Ricci tensor of
hypercomplex group manifolds. Our results can be used as a starting point to
obtain more general matter-couplings to Poincare supergravity.Comment: 67 pages; v2: title of reference changed and small editing
corrections; v3: small typing errors corrected, version published in JHEP;
v4: typos corrected; v5: additional term in (2.109) and (4.11); v6: change of
order of indices in (2.89
Recontacting patients in clinical genetics services: recommendations of the European Society of Human Genetics
Technological advances have increased the availability of genomic data in research and the clinic. If, over time, interpretation of the significance of the data changes, or new information becomes available, the question arises as to whether recontacting the patient and/or family is indicated. The Public and Professional Policy Committee of the European Society of Human Genetics (ESHG), together with research groups from the UK and the Netherlands, developed recommendations on recontacting which, after public consultation, have been endorsed by ESHG Board. In clinical genetics, recontacting for updating patients with new, clinically significant information related to their diagnosis or previous genetic testing may be justifiable and, where possible, desirable. Consensus about the type of information that should trigger recontacting converges around its clinical and personal utility. The organization of recontacting procedures and policies in current health care systems is challenging. It should be sustainable, commensurate with previously obtained consent, and a shared responsibility between healthcare providers, laboratories, patients, and other stakeholders. Optimal use of the limited clinical resources currently available is needed. Allocation of dedicated resources for recontacting should be considered. Finally, there is a need for more evidence, including economic and utility of information for people, to inform which strategies provide the most cost-effective use of healthcare resources for recontacting