2,256 research outputs found
Statistical analysis and modelling of weather radar beam propagation conditions in the Po Valley (Italy)
Ground clutter caused by anomalous propagation (anaprop) can affect seriously radar rain rate estimates, particularly in fully automatic radar processing systems, and, if not filtered, can produce frequent false alarms. A statistical study of anomalous propagation detected from two operational C-band radars in the northern Italian region of Emilia Romagna is discussed, paying particular attention to its diurnal and seasonal variability. The analysis shows a high incidence of anaprop in summer, mainly in the morning and evening, due to the humid and hot summer climate of the Po Valley, particularly in the coastal zone. Thereafter, a comparison between different techniques and datasets to retrieve the vertical profile of the refractive index gradient in the boundary layer is also presented. In particular, their capability to detect anomalous propagation conditions is compared. Furthermore, beam path trajectories are simulated using a multilayer ray-tracing model and the influence of the propagation conditions on the beam trajectory and shape is examined. High resolution radiosounding data are identified as the best available dataset to reproduce accurately the local propagation conditions, while lower resolution standard TEMP data suffers from interpolation degradation and Numerical Weather Prediction model data (Lokal Model) are able to retrieve a tendency to superrefraction but not to detect ducting conditions. Observing the ray tracing of the centre, lower and upper limits of the radar antenna 3-dB half-power main beam lobe it is concluded that ducting layers produce a change in the measured volume and in the power distribution that can lead to an additional error in the reflectivity estimate and, subsequently, in the estimated rainfall rate
Experiments on clinical observation and judgement in the assessment of depression: profiled videotapes and Judgement Analysis
Variations within and between observer-judges reduce the accuracy of clinical research. Judgement Analysis allows strategies to be developed and applied which reduce variation in judgement. The prediction that the removal of important sources of error variance by this means would reduce the likelihood of committing a Type 2 Error was supported by the application of Judgement Analysis to assessments by 15 psychiatrists of 92 patients in a clinical trial of 2 antidepressive treatments. The statistical significance of differences between the effect of the treatments on the severity of depression was increased, and significant differences appeared earlier. Ten stimulated patient profiles were also converted into narrative case histories, enacted by experienced psychiatrists or psychologists and videotaped. The participants' judgements of the overall severity of the depression were in good agreement with those they had made on the original cases. Videotapes so prepared help training to reduce variation in observation, just as Judgement Analysis can lead to reductions in the variation of judgemen
Antidepressant drugs and the response in the placebo group: the real problem lies in our understanding of the issue
In a recent paper, Horder and colleagues (Horder et al., 2010, J Psychopharmacol 25: 1277–1288) have suggested that the mainproblem in the Kirsch analysis is methodological. We argue that the results are similar irrespective of the method used. In our opinion the data suggest that placebo and drug effects are non-additive: antidepressants act independently of depression severity, while the placebo effect is present only in milder cases. While the response in the placebo group is due to unstable ‘noise’ and ‘artefacts’, the medication effect is reliable, valid and stable
Rotated stripe order and its competition with superconductivity in LaSrCuO
We report the observation of a bulk charge modulation in
LaSrCuO (LSCO) with a characteristic in-plane wave-vector
of (0.236, ), with =0.011 r.l.u. The transverse shift of
the ordering wave-vector indicates the presence of rotated charge-stripe
ordering, demonstrating that the charge ordering is not pinned to the Cu-O bond
direction. On cooling through the superconducting transition, we find an abrupt
change in the growth of the charge correlations and a suppression of the charge
order parameter indicating competition between the two orderings. Orthorhombic
LSCO thus helps bridge the apparent disparities between the behavior previously
observed in the tetragonal "214" cuprates and the orthorhombic yttrium and
bismuth-based cuprates and thus lends strong support to the idea that there is
a common motif to charge order in all cuprate families.Comment: 6 pages, 4 figue
Quality of life and well-being of carers of people with dementia: are there differences between working and nonworking carers? Results from the IDEAL program
The aim of this study was to identify the differences in quality of life (QoL) and well-being between working and nonworking dementia carers and the relative contribution of psychological characteristics, caregiving experience, and social support. Multiple regressions modeled the contribution of working status, caregiver experiences, and psychological and social resources to carer QoL (EQ-5D) and well-being (WHO-5). After controlling for age, gender, carer–dyad relationship, and severity of dementia, working status contributed significant variance to EQ-5D (2%) but not to WHO-5 scores. Independent of working status, higher self-esteem and reduced stress contributed to variance in both models. Self-efficacy, social support, and positive perceptions of caregiving additionally contributed to higher WHO-5 scores. Working status associated with higher EQ-5D QoL; this may reflect the sustained sense of independence associated with supported work opportunities for carers. Outside of working status, the findings support the importance of psychological and social factors as targets to improved mental health for dementia carers
The Pharmacopsychometric Triangle to Illustrate the Effectiveness of T-PEMF Concomitant with Antidepressants in Treatment Resistant Patients: A Double-Blind, Randomised, Sham-Controlled Trial Revisited with Focus on the Patient-Reported Outcomes
Background. Our T-PEMF trial has been revisited with focus on the pharmacopsychometric triangle in which effect size is used when comparing wanted versus unwanted clinical effects and quality of life as outcomes. In this analysis, we have especially focused on the self-reported HAM-D6. Methods. The antidepressive medication which the patients were resistant to was kept unchanged during the five weeks of active versus sham T-PEMF. Results. In total 21, patients received active T-PEMF, and 19 patients received sham T-PEMF. The effect size was 1.02 and 0.90, respectively, on HAM-D6 and HAM-D6-S. Concerning side effects, the active T-PEMF reduced the baseline score on concentration problems with an effect size of 0.44 while inducing more autonomic symptoms than sham T-PEMF with an effect size of −0.41. The advantage of active over sham T-PEMF obtained an effect size of 0.48. Conclusion. Active T-PEMF was found superior to sham T-PEMF within the pharmacopsychometric triangle with a clinically significant effect size level above 0.40
On the Phenomenology of Hydrodynamic Shear Turbulence
The question of a purely hydrodynamic origin of turbulence in accretion disks
is reexamined, on the basis of a large body of experimental and numerical
evidence on various subcritical (i.e., linearly stable) hydrodynamic flows.
One of the main points of this paper is that the length scale and velocity
fluctuation amplitude which are characteristic of turbulent transport in these
flows scale like , where is the minimal Reynolds number for
the onset of fully developed turbulence. From this scaling, a simple
explanation of the dependence of with relative gap width in subcritical
Couette-Taylor flows is developed. It is also argued that flows in the shearing
sheet limit should be turbulent, and that the lack of turbulence in all such
simulations performed to date is most likely due to a lack of resolution, as a
consequence of the effect of the Coriolis force on the large scale fluctuations
of turbulent flows.
These results imply that accretion flows should be turbulent through
hydrodynamic processes. If this is the case, the Shakura-Sunyaev
parameter is constrained to lie in the range in accretion
disks, depending on unknown features of the mechanism which sustains
turbulence. Whether the hydrodynamic source of turbulence is more efficient
than the MHD one where present is an open question.Comment: 31 pages, 3 figures. Accepted for publication in Ap
Implementation of the Multiple Point Principle in the Two-Higgs Doublet Model of type II
The multiple point principle (MPP) is applied to the non--supersymmetric
two-Higgs doublet extension of the Standard Model (SM). The existence of a
large set of degenerate vacua at some high energy scale caused by the MPP
results in a few relations between Higgs self-coupling constants which can be
examined at future colliders. The numerical analysis reveals that these MPP
conditions constrain the mass of the SM--like Higgs boson to lie below 180 GeV
for a wide set of MPP scales and .Comment: 26 pages, 3 figures, some minor changes to the tex
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