458 research outputs found
Experiments on reinforced brick masonry vaulted light roofs
This paper describes structural tests of thin vaults made of reinforced brick masonry. The experiments consist of concentrated loading tests of 14 full-scale laboratory vaults. These vaults are designed to include common situations such as short- to midspan length, low-mid-high rise, rigid-flexible-sliding supports, instantaneous-sustained loading, low-high strength mortar, point-line loading, central-eccentric loading, point-line supports, hinged-clamped supports, symmetric-asymmetric shape, double layer versus single layer reinforcement, and uniaxial-biaxial bending, among others. The tests mainly aim to obtain the collapse loads and to characterize the pre- and post-peak response. The results show satisfactory structural performance, both in terms of ductility and strength. Moreover, it is possible to predict the structural response with numerical models developed specifically for this purpose. Flat specimens were also tested to determine the punching shear strength of the vaults. This work is part of a larger research project aimed at promoting innovative semi-prefabrication techniques for reinforced brick masonry vaulted light roofs
Wilson-Polchinski exact renormalization group equation for O(N) systems: Leading and next-to-leading orders in the derivative expansion
With a view to study the convergence properties of the derivative expansion
of the exact renormalization group (RG) equation, I explicitly study the
leading and next-to-leading orders of this expansion applied to the
Wilson-Polchinski equation in the case of the -vector model with the
symmetry . As a test, the critical exponents and as well as the subcritical exponent (and higher ones) are estimated
in three dimensions for values of ranging from 1 to 20. I compare the
results with the corresponding estimates obtained in preceding studies or
treatments of other exact RG equations at second order. The
possibility of varying allows to size up the derivative expansion method.
The values obtained from the resummation of high orders of perturbative field
theory are used as standards to illustrate the eventual convergence in each
case. A peculiar attention is drawn on the preservation (or not) of the
reparametrisation invariance.Comment: Dedicated to Lothar Sch\"afer on the occasion of his 60th birthday.
Final versio
Nitrogen deficiency increases basal branching and modifies visual quality of the rose bushes
Rosebush architecture resulting from the spatial organisation of the plant axes induces plant shape and consequently within ornamental horticulture context, its visual quality and commercial value. This architecture can be modulated by environmental conditions, particularly in the horticulture context in which the possibilities to control growing conditions are numerous. The objectives of the study were to determine, in young rose bushes, (1) whether short periods of nitrogen deficiency affect branching and (2) whether this effect is sufficient to modify the visual quality of the plant in a sustainable manner. Between vegetative bud burst and the petal colour visible stage of the generated primary branch, young rooted cuttings of bush rose (cv Radrazz) were subjected to one of three nitrogen regimes: (1) no nitrogen deficiency, (2) continuous nitrogen deficiency, i.e. 35 days of N deficiency, and (3) nitrogen deficiency restricted to the flowering stages, i.e. 18 days of N deficiency. After the petal colour visible stage, all three groups of plants were supplied continuously with nitrogen. We observed the morphology of the axes and the kinetics of axillary bud burst. Twelve weeks after the petal colour visible stage, the visual quality of the rose bushes was evaluated by an expert jury. We found that nitrogen deficiencies (1) increased bud burst ratios in the medial and basal zones of the primary branch, (2) delayed the bud burst in the apical zone of the primary branch and (3) had long-term effects on plant visual quality. The continuous nitrogen deficiency regime produced flatter, more asymmetric and less vigorous rose bushes than the no nitrogen deficiency regime. By contrast, nitrogen deficiency during the flowering stages only resulted in more symmetric, taller and more vigorous rose bushes than the no nitrogen deficiency regime. Based on these results, the role of nitrogen on bud burst was discussed and candidate processes at the origin of the visual quality modification were suggested. This new approach combining ecophysiology and sensory assessment of ornamental plants enabled the identification of some early architecture components to be correlated with later visual quality characteristics and then to better target the physiological processes of interest
Acute pyelonephritis and pregnancy
Las infecciones del tracto urinario en el embarazo abarcan la bacteriuria asintomática, cistitis aguda y pielonefritis aguda. Ésta Ăşltima es una infecciĂłn del parĂ©nquima renal caracterizada por fiebre, dolor costovertebral, náuseas y/o vĂłmitos sin sĂntomas de cistitis. Afecta al 1-2% de los embarazos siendo Ă©ste un factor de riesgo preponderante en la patologĂa por los cambios anatĂłmicos y fisiolĂłgicos que en Ă©l suceden. La pielonefritis aguda causa numerosos ingresos hospitalarios por año y se ha observado un aumento de la casuĂstica por lo que consideramos importante su investigaciĂłn para una mejor prevenciĂłn y tratamiento oportuno
Interventions to facilitate shared decision-making using decision aids with patients in Primary Health Care: A systematic review
BACKGROUND: Shared decision making (SDM) is a process within the physician-patient relationship applicable to any clinical action, whether diagnostic, therapeutic, or preventive in nature. It has been defined as a process of mutual respect and participation between the doctor and the patient. The aim of this study is to determine the effectiveness of decision aids (DA) in primary care based on changes in adherence to treatments, knowledge, and awareness of the disease, conflict with decisions, and patients'' and health professionals'' satisfaction with the intervention. METHODS: A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted in Medline, CINAHL, Embase, the Cochrane Central Register of Controlled Trials, and the NHS Economic Evaluation Database. The inclusion criteria were randomized clinical trials as study design; use of SDM with DA as an intervention; primary care as clinical context; written in English, Spanish, and Portuguese; and published between January 2007 and January 2019. The risk of bias of the included studies in this review was assessed according to the Cochrane Collaboration''s tool. RESULTS: Twenty four studies were selected out of the 201 references initially identified. With the use of DA, the use of antibiotics was reduced in cases of acute respiratory infection and decisional conflict was decreased when dealing with the treatment choice for atrial fibrillation and osteoporosis. The rate of determination of prostate-specific antigen (PSA) in the prostate cancer screening decreased and colorectal cancer screening increased. Both professionals and patients increased their knowledge about depression, type 2 diabetes, and the perception of risk of acute myocardial infarction at 10 years without statins and with statins. The satisfaction was greater with the use of DA in choosing the treatment for depression, in cardiovascular risk management, in the treatment of low back pain, and in the use of statin therapy in diabetes. Blinding of outcomes assessment was the most common bias. CONCLUSIONS: DA used in primary care are effective to reduce decisional conflict and improve knowledge on the disease and treatment options, awareness of risk, and satisfaction with the decisions made. More studies are needed to assess the impact of shared decision making in primary care
Towards Classification of Phase Transitions in Reaction--Diffusion Models
Equilibrium phase transitions are associated with rearrangements of minima of
a (Lagrangian) potential. Treatment of non-equilibrium systems requires
doubling of degrees of freedom, which may be often interpreted as a transition
from the ``coordinate'' to the ``phase'' space representation. As a result, one
has to deal with the Hamiltonian formulation of the field theory instead of the
Lagrangian one. We suggest a classification scheme of phase transitions in
reaction-diffusion models based on the topology of the phase portraits of
corresponding Hamiltonians. In models with an absorbing state such a topology
is fully determined by intersecting curves of zero ``energy''. We identify four
families of topologically distinct classes of phase portraits stable upon RG
transformations.Comment: 14 pages, 9 figure
Mean-field analysis of the q-voter model on networks
We present a detailed investigation of the behavior of the nonlinear q-voter
model for opinion dynamics. At the mean-field level we derive analytically, for
any value of the number q of agents involved in the elementary update, the
phase diagram, the exit probability and the consensus time at the transition
point. The mean-field formalism is extended to the case that the interaction
pattern is given by generic heterogeneous networks. We finally discuss the case
of random regular networks and compare analytical results with simulations.Comment: 20 pages, 10 figure
Comparison of Different Parallel Implementations of the 2+1-Dimensional KPZ Model and the 3-Dimensional KMC Model
We show that efficient simulations of the Kardar-Parisi-Zhang interface
growth in 2 + 1 dimensions and of the 3-dimensional Kinetic Monte Carlo of
thermally activated diffusion can be realized both on GPUs and modern CPUs. In
this article we present results of different implementations on GPUs using CUDA
and OpenCL and also on CPUs using OpenCL and MPI. We investigate the runtime
and scaling behavior on different architectures to find optimal solutions for
solving current simulation problems in the field of statistical physics and
materials science.Comment: 14 pages, 8 figures, to be published in a forthcoming EPJST special
issue on "Computer simulations on GPU
The Src Homology and Collagen A (ShcA) adaptor protein is required for the spatial organization of the costamere/Z-disk network during heart development
ShcA (Src Homology and Collagen A) is an adaptor protein that binds to tyrosine kinase receptors. Its germ line deletion is embryonic lethal with abnormal cardiovascular system formation, and its role in cardiovascular development is unknown. To investigate its functional role in cardiovascular development in mice, ShcA was deleted in cardiomyocytes and vascular smooth muscle cells by crossing ShcA flox mice with SM22a-Cre transgenic mice. Conditional mutant mice developed signs of severe dilated cardiomyopathy, myocardial infarctions, and premature death. No evidence of a vascular contribution to the phenotype was observed. Histological analysis of the heart revealed aberrant sarcomeric Z-disk and M-band structures, and misalignments of T-tubules with Z-disks. We find that not only the ErbB3/Neuregulin signaling pathway but also the baroreceptor reflex response, which have been functionally associated, are altered in the mutant mice. We further demonstrate that ShcA interacts with Caveolin-1 and the costameric protein plasma membrane Ca2+/calmodulin-dependent ATPase (PMCA), and that its deletion leads to abnormal dystrophin signaling. Collectively, these results demonstrate that ShcA interacts with crucial proteins and pathways that link Z-disk and costamere
Far-from-equilibrium quantum many-body dynamics
The theory of real-time quantum many-body dynamics as put forward in Ref.
[arXiv:0710.4627] is evaluated in detail. The formulation is based on a
generating functional of correlation functions where the Keldysh contour is
closed at a given time. Extending the Keldysh contour from this time to a later
time leads to a dynamic flow of the generating functional. This flow describes
the dynamics of the system and has an explicit causal structure. In the present
work it is evaluated within a vertex expansion of the effective action leading
to time evolution equations for Green functions. These equations are applicable
for strongly interacting systems as well as for studying the late-time
behaviour of nonequilibrium time evolution. For the specific case of a bosonic
N-component phi^4 theory with contact interactions an s-channel truncation is
identified to yield equations identical to those derived from the 2PI effective
action in next-to-leading order of a 1/N expansion. The presented approach
allows to directly obtain non-perturbative dynamic equations beyond the widely
used 2PI approximations.Comment: 20 pp., 6 figs; submitted version with added references and typos
corrected
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