8,995 research outputs found
Best practice in undertaking and reporting health technology assessments : Working Group 4 report
[Executive Summary] The aim of Working Group 4 has been to develop and disseminate best practice in undertaking and reporting assessments, and to identify needs for methodologic development. Health technology assessment (HTA) is a multidisciplinary activity that systematically examines the technical performance, safety, clinical efficacy, and effectiveness, cost, costeffectiveness, organizational implications, social consequences, legal, and ethical considerations of the application of a health technology (18). HTA activity has been continuously increasing over the last few years. Numerous HTA agencies and other institutions (termed in this report “HTA doers”) across Europe are producing an important and growing amount of HTA information. The objectives of HTA vary considerably between HTA agencies and other actors, from a strictly political decision making–oriented approach regarding advice on market licensure, coverage in benefits catalogue, or investment planning to information directed to providers or to the public. Although there seems to be broad agreement on the general elements that belong to the HTA process, and although HTA doers in Europe use similar principles (41), this is often difficult to see because of differences in language and terminology. In addition, the reporting of the findings from the assessments differs considerably. This reduces comparability and makes it difficult for those undertaking HTA assessments to integrate previous findings from other HTA doers in a subsequent evaluation of the same technology. Transparent and clear reporting is an important step toward disseminating the findings of a HTA; thus, standards that ensure high quality reporting may contribute to a wider dissemination of results. The EUR-ASSESS methodologic subgroup already proposed a framework for conducting and reporting HTA (18), which served as the basis for the current working group. New developments in the last 5 years necessitate revisiting that framework and providing a solid structure for future updates. Giving due attention to these methodologic developments, this report describes the current “best practice” in both undertaking and reporting HTA and identifies the needs for methodologic development. It concludes with specific recommendations and tools for implementing them, e.g., by providing the structure for English-language scientific summary reports and a checklist to assess the methodologic and reporting quality of HTA reports
Static quantities of the W boson in the SU_L(3) X U_X(1) model with right-handed neutrinos
The static electromagnetic properties of the boson, and
, are calculated in the SU_L(3)} \times U_X(1) model with
right-handed neutrinos. The new contributions from this model arise from the
gauge and scalar sectors. In the gauge sector there is a new contribution from
a complex neutral gauge boson and a singly-charged gauge boson .
The mass of these gauge bosons, called bileptons, is expected to be in the
range of a few hundreds of GeV according to the current bounds from
experimental data. If the bilepton masses are of the order of 200 GeV, the size
of their contribution is similar to that obtained in other weakly coupled
theories. However the contributions to both and are
negligible for very heavy or degenerate bileptons. As for the scalar sector, an
scenario is examined in which the contribution to the form factors is
identical to that of a two-Higgs-doublet model. It is found that this sector
would not give large corrections to and .Comment: New material included. Final version to apppear in Physical Review
Fermion contribution to the static quantities of arbitrarily charged vector bosons
We present an analysis of the one-loop contribution from left- and
right-handed fermions to the static electromagnetic properties of an
arbitrarily charged no self-conjugate vector boson . Particular emphasis is
given to the case of a no self-conjugate neutral boson . Regardless the
electric charge of the boson, a fermionic loop can induce the two CP-even
form factors but only one CP-odd. As a result the corresponding electric dipole
moment is directly proportional to the magnetic quadrupole moment. The CP-odd
form factor might be severely suppressed since it requires the presence of both
left- and right-handed fermions. The behavior of the form factors is analyzed
for several scenarios of the fermion masses in the context of the decoupling
theorem.Comment: 12 pages, 3 figures, submitted to Journal of Physics
A super-Earth orbiting the nearby M-dwarf GJ 536
We report the discovery of a super-Earth orbiting the star GJ 536 based on
the analysis of the radial-velocity time series from the HARPS and HARPS-N
spectrographs. GJ 536 b is a planet with a minimum mass M sin of 5.36 +-
0.69 Me with an orbital period of 8.7076 +- 0.0025 days at a distance of
0.066610(13) AU, and an orbit that is consistent with circular. The host star
is the moderately quiet M1 V star GJ 536, located at 10 pc from the Sun. We
find the presence of a second signal at 43 days that we relate to stellar
rotation after analysing the time series of Ca II H&K and H alpha spectroscopic
indicators and photometric data from the ASAS archive. We find no evidence
linking the short period signal to any activity proxy. We also tentatively
derived a stellar magnetic cycle of less than 3 years.Comment: 14 pages, 14 figures, 5 tables, Accepted in A&
The pair potential of colloidal stars
We report on the construction of colloidal stars: 1 micrometer polystyrene
beads grafted with a dense brush of 1 micrometer long and 10 nm wide
semi-flexible filamentous viruses. The pair interaction potentials of colloidal
stars are measured using an experimental implementation of umbrella sampling, a
technique originally developed in computer simulations in order to probe rare
events. The influence of ionic strength and grafting density on the interaction
is measured. Good agreements are found between the measured interactions and
theoretical predictions based upon the osmotic pressure of counterions.Comment: 5 pages, 3 figures. Changed conten
Quantum Cosmology in Scalar-Tensor Theories With Non Minimal Coupling
Quantization in the minisuperspace of non minimal scalar-tensor theories
leads to a partial differential equation which is non separable. Through a
conformal transformation we can recast the Wheeler-DeWitt equation in an
integrable form, which corresponds to the minimal coupling case, whose general
solution is known. Performing the inverse conformal transformation in the
solution so found, we can construct the corresponding one in the original
frame. This procedure can also be employed with the bohmian trajectories. In
this way, we can study the classical limit of some solutions of this quantum
model. While the classical limit of these solutions occurs for small scale
factors in the Einstein's frame, it happens for small values of the scalar
field non minimally coupled to gravity in the Jordan's frame, which includes
large scale factors.Comment: latex, 18 page
Flavour constraints on scenarios with two or three heavy squark generations
We re-assess constraints from flavour-changing neutral currents in the kaon
system on supersymmetric scenarios with a light gluino, two heavy generations
of squarks and a lighter third generation. We compute for the first time limits
in scenarios with three heavy squark families, taking into account QCD
corrections at the next-to-leading order. We compare our limits with those in
the case of two heavy families. We use the mass insertion approximation and
consider contributions from gluino exchange to constrain the mixing between the
first and second squark generation. While it is not possible to perform a
general analysis, we assess the relevance of each kind of flavour- and
CP-violating parameters. We also provide ready to use magic numbers for the
computation of the Wilson coefficients at 2 GeV for these scenarios.Comment: 23 pages, 14 figures; v3: matches published version (contains
improvements in the presentation and clarifications
Performance of discrete heat engines and heat pumps in finite time
The performance in finite time of a discrete heat engine with internal
friction is analyzed. The working fluid of the engine is composed of an
ensemble of noninteracting two level systems. External work is applied by
changing the external field and thus the internal energy levels. The friction
induces a minimal cycle time. The power output of the engine is optimized with
respect to time allocation between the contact time with the hot and cold baths
as well as the adiabats. The engine's performance is also optimized with
respect to the external fields. By reversing the cycle of operation a heat pump
is constructed. The performance of the engine as a heat pump is also optimized.
By varying the time allocation between the adiabats and the contact time with
the reservoir a universal behavior can be identified. The optimal performance
of the engine when the cold bath is approaching absolute zero is studied. It is
found that the optimal cooling rate converges linearly to zero when the
temperature approaches absolute zero.Comment: 45 pages LaTeX, 25 eps figure
SAPPHiRE: a Small Gamma-Gamma Higgs Factory
A new particle with mass ~ 125 GeV that resembles the Higgs boson has
recently been discovered by ATLAS and CMS. We propose a low-energy gamma-gamma
collider as a cost- and time-efficient option for a Higgs factory capable of
studying this particle in detail. In the past, this option has been suggested
as a possible application of the CLIC two-beam accelerator technology (the CLIC
Higgs Experiment, CLICHE) or as an option for the ILC. Here we propose a design
based on a pair of \sim 10 GeV recirculating Linacs (Small Accelerator for
Photon-Photon Higgs production using Recirculating Electrons, SAPPHiRE) similar
in design to those proposed for the LHeC. We present parameters for the e-
beams and sketch a laser backscattering system capable of producing a
gamma-gamma peak luminosity of 0.36 \times 10^34/cm2/s with E_CM (gamma-gamma)
\sim 125 GeV. A gamma-gamma collider with such a luminosity could be used to
measure accurately the mass, bbar, WW\ast, and gamma-gamma decays of the Higgs
boson. We also comment on possible synergies with other projects such as LHeC,
the ILC or CLIC, and on other physics prospects in gamma-gamma and e-gamma
collisions.Comment: 13 pages, 7 eps figures, Submitted to the European Particle Physics
Strategy Preparatory Grou
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