577 research outputs found
Mid-infrared Suspended Waveguide Platform and Building Blocks
In this work we present our recent progress in the development of a platform for the mid-infrared wavelength range, based on suspended silicon waveguide with subwavelength metamaterial cladding. The platform has some intrinsic advantages, which make it a very promising candidate for sensing applications in the fingerprint region. Specifically, it can cover the full transparency window of silicon (up to a wavelength of 8 μm), only requires one lithographic etch-step and can be designed for strong light-matter interaction. Design rules, practical aspects of the fabrication process and experimental results of a complete set of elemental building blocks operating at two very different wavelengths, 3.8 μm and 7.67 μm, will be discussed. Propagation losses as low as 0.82 dB/cm at λo=3.8 μm and 3.1 dB/cm at λo=7.67 μm are attained, for the interconnecting waveguides.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
The spinorial geometry of supersymmetric heterotic string backgrounds
We determine the geometry of supersymmetric heterotic string backgrounds for
which all parallel spinors with respect to the connection with
torsion , the NSNS three-form field strength, are Killing. We find
that there are two classes of such backgrounds, the null and the timelike. The
Killing spinors of the null backgrounds have stability subgroups
K\ltimes\bR^8 in , for , SU(4), , and , and the Killing spinors of the timelike backgrounds have
stability subgroups , SU(3), SU(2) and . The former admit a single
null -parallel vector field while the latter admit a timelike and
two, three, five and nine spacelike -parallel vector fields,
respectively. The spacetime of the null backgrounds is a Lorentzian
two-parameter family of Riemannian manifolds with skew-symmetric torsion.
If the rotation of the null vector field vanishes, the holonomy of the
connection with torsion of is contained in . The spacetime of time-like
backgrounds is a principal bundle with fibre a Lorentzian Lie group and
base space a suitable Riemannian manifold with skew-symmetric torsion. The
principal bundle is equipped with a connection which determines the
non-horizontal part of the spacetime metric and of . The curvature of
takes values in an appropriate Lie algebra constructed from that of
. In addition has only horizontal components and contains the
Pontrjagin class of . We have computed in all cases the Killing spinor
bilinears, expressed the fluxes in terms of the geometry and determine the
field equations that are implied by the Killing spinor equations.Comment: 73pp. v2: minor change
Geometric phases for generalized squeezed coherent states
A simple technique is used to obtain a general formula for the Berry phase
(and the corresponding Hannay angle) for an arbitrary Hamiltonian with an
equally-spaced spectrum and appropriate ladder operators connecting the
eigenstates. The formalism is first applied to a general deformation of the
oscillator involving both squeezing and displacement. Earlier results are shown
to emerge as special cases. The analysis is then extended to multiphoton
squeezed coherent states and the corresponding anholonomies deduced.Comment: 15 page
Plasma matrix metalloproteinases in neonates having surgery for congenital heart disease
During cardiopulmonary-bypass matrix-metalloproteinases released may contribute to ventricular dysfunction. This study was to determine plasma matrix-metalloproteinases in neonates after cardiopulmonary-bypass and their relation to post-operative course. A prospective observational study included 18 neonates having cardiac surgery. Plasma matrix-metalloproteinases-2 and 9 activities were measured by gelatin-zymography pre-operatively, on starting cardiopulmonarybypass, 7–8 min after aortic cross-clamp release, and 1h, 4h, 24h, and 3d after cardiopulmonary-bypass. Plasma concentrations of their tissue inhibitors 1 and 2 were determined by enzyme-linked immunosorbent assay. Cardiac function was assessed by serial echocardiography. Paired t-tests and Wilcoxon tests were used to assess temporal changes, and linear correlation with simultaneous clinical and cardiac function parameters were assessed using Pearson's product-moment correlation coefficient. Plasma matrix-metalloproteinases activities and their tissue inhibitor concentrations decreased during cardiopulmonary-bypass. Matrix-metalloproteinase-2 plasma activity increased progressively starting 1h after cardiopulmonarybypass and returned to pre-operative levels at 24h. Matrix-metalloproteinase-9 plasma activity increased significantly after release of aortic cross-clamp, peaked 7–8min later, and returned to baseline at 24h. Plasma tissueinhibitor 1 and 2 concentrations increased 1h after cardiopulmonary-bypass. Cardiac function improved from 4h to 3d after surgery (p<0.05). There was no evidence of significant correlations between matrix-metalloproteinases or their inhibitors and cardiac function, inotrope scores, organ dysfunction scores, ventilation days, or hospital days. The temporal profile of plasma matrix-metalloproteinases and their inhibitors after cardiopulmonary-bypass in neonates are similar to adults. In neonates, further study should determine whether circulating matrix-metalloproteinases are useful biomarkers of disease activity locally within the myocardium, and hence of clinical outcomes
Finite-time future singularities in modified Gauss-Bonnet and gravity and singularity avoidance
We study all four types of finite-time future singularities emerging in
late-time accelerating (effective quintessence/phantom) era from
-gravity, where and are the Ricci scalar and the
Gauss-Bonnet invariant, respectively. As an explicit example of
-gravity, we also investigate modified Gauss-Bonnet gravity,
so-called -gravity. In particular, we reconstruct the -gravity and
-gravity models where accelerating cosmologies realizing the
finite-time future singularities emerge. Furthermore, we discuss a possible way
to cure the finite-time future singularities in -gravity and
-gravity by taking into account higher-order curvature
corrections. The example of non-singular realistic modified Gauss-Bonnet
gravity is presented. It turns out that adding such non-singular modified
gravity to singular Dark Energy makes the combined theory to be non-singular
one as well.Comment: 35 pages, no figure, published version, references adde
Origin of the submillimeter radio emission during the time-extended phase of a solar flare
Solar flares observed in the 200-400 GHz radio domain may exhibit a slowly
varying and time-extended component which follows a short (few minutes)
impulsive phase and which lasts for a few tens of minutes to more than one
hour. The few examples discussed in the literature indicate that such
long-lasting submillimeter emission is most likely thermal bremsstrahlung. We
present a detailed analysis of the time-extended phase of the 2003 October 27
(M6.7) flare, combining 1-345 GHz total-flux radio measurements with X-ray,
EUV, and H{\alpha} observations. We find that the time-extended radio emission
is, as expected, radiated by thermal bremsstrahlung. Up to 230 GHz, it is
entirely produced in the corona by hot and cool materials at 7-16 MK and 1-3
MK, respectively. At 345 GHz, there is an additional contribution from
chromospheric material at a few 10^4 K. These results, which may also apply to
other millimeter-submillimeter radio events, are not consistent with the
expectations from standard semi-empirical models of the chromosphere and
transition region during flares, which predict observable radio emission from
the chromosphere at all frequencies where the corona is transparent.Comment: 27 pages, 7 figure
The comparative responsiveness of Hospital Universitario Princesa Index and other composite indices for assessing rheumatoid arthritis activity
Objective
To evaluate the responsiveness in terms of correlation of the Hospital Universitario La Princesa Index (HUPI) comparatively to the traditional composite indices used to assess disease activity in rheumatoid arthritis (RA), and to compare the performance of HUPI-based response criteria with that of the EULAR response criteria.
Methods
Secondary data analysis from the following studies: ACT-RAY (clinical trial), PROAR (early RA cohort) and EMECAR (pre-biologic era long term RA cohort). Responsiveness was evaluated by: 1) comparing change from baseline (Delta) of HUPI with Delta in other scores by calculating correlation coefficients; 2) calculating standardised effect sizes. The accuracy of response by HUPI and by EULAR criteria was analyzed using linear regressions in which the dependent variable was change in global assessment by physician (Delta GDA-Phy).
Results
Delta HUPI correlation with change in all other indices ranged from 0.387 to 0.791); HUPI's standardized effect size was larger than those from the other indices in each database used. In ACT-RAY, depending on visit, between 65 and 80% of patients were equally classified by HUPI and EULAR response criteria. However, HUPI criteria were slightly more stringent, with higher percentage of patients classified as non-responder, especially at early visits. HUPI response criteria showed a slightly higher accuracy than EULAR response criteria when using Delta GDA-Phy as gold standard.
Conclusion
HUPI shows good responsiveness in terms of correlation in each studied scenario (clinical trial, early RA cohort, and established RA cohort). Response criteria by HUPI seem more stringent than EULAR''s
The NUPHAC-EU Framework for Nurses' Role in Interprofessional Pharmaceutical Care: Cross-Sectional Evaluation in Europe.
Clear role descriptions promote the quality of interprofessional collaboration. Currently, it is unclear to what extent healthcare professionals consider pharmaceutical care (PC) activities to be nurses' responsibility in order to obtain best care quality. This study aimed to create and evaluate a framework describing potential nursing tasks in PC and to investigate nurses' level of responsibility. A framework of PC tasks and contextual factors was developed based on literature review and previous DeMoPhaC project results. Tasks and context were cross-sectionally evaluated using an online survey in 14 European countries. A total of 923 nurses, 240 physicians and 199 pharmacists responded. The majority would consider nurses responsible for tasks within: medication self-management (86-97%), patient education (85-96%), medication safety (83-95%), monitoring adherence (82-97%), care coordination (82-95%), and drug monitoring (78-96%). The most prevalent level of responsibility was 'with shared responsibility'. Prescription management tasks were considered to be nurses' responsibility by 48-81% of the professionals. All contextual factors were indicated as being relevant for nurses' role in PC by at least 74% of the participants. No task nor contextual factor was removed from the framework after evaluation. This framework can be used to enable healthcare professionals to openly discuss allocation of specific (shared) responsibilities and tasks
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