An analysis of the development of home exchange organizations

Dit onderzoek draagt bij aan een beter begrip van het fenomeen woningruil, hierbij is gelet op de historische ontwikkeling van de woningruil, bemiddelingsprocessen, lidmaatschap profielen en de rol van media. Het internet heeft voor een interactiever proces gezorgd en vergemakkelijkt woningruil kernels die, door de manier waarop ze georganiseerd zijn, een zekere mate van zelf-organisatie toestaan. Processen van specialisatie en differentiatie veranderen het ‘Woningruil bemiddelings landschap’

The effectiveness of multifactorial and multicomponent interventions for the prevention of falls for adults in hospital settings: a systematic review and meta-analysis.

The objective of this systematic review and meta-analysis was to evaluate the effectiveness of multicomponent and multifactorial interventions for reducing falls in adult in-patients. Falls are the most common cause of accidental injury in hospitals worldwide, resulting in high human and economic costs. In attempts to reduce the number of falls, a wide range of interventions have been employed, often in combination, either as a package (multicomponent) or tailored to the individual (multifactorial). There is a need to synthesise the findings from primary studies and assess which approach may be more effective. The systematic review included studies comprising adult inpatients aged 18 years and over from any hospital setting including elective, non-elective, day-case and secondary care. Randomized controlled trials (RCT), cluster-randomised trials, quasi-experimental controlled trials and historical controlled trials were included that presented sufficient information regarding the rate or number of falls. This effectiveness review was conducted in accordance with JBI methodology and was guided by an a priori protocol. A comprehensive 3-step search strategy was employed across 14 databases. Screening was conducted by two independent reviewers, and data was extracted using a bespoke data extraction tool designed for this review. Methodological quality was assessed using adapted versions of JBI critical appraisal checklists. Meta-analyses were conducted within a Bayesian framework to interpret results probabilistically and account for covariance in multiple sets of falls data reported in the same study. Effect sizes were calculated by comparing the rate or number of falls in the intervention group compared with usual care. Narrative syntheses were conducted on studies that met the inclusion criteria but did not provide sufficient data for inclusion in meta-analyses. A total of 9,637 records were obtained and following screening 24 studies were included in this review, 21 of which presented sufficient information to be included in meta-analyses. Most studies (n=16) comprised a weaker historical control design with 6 quasi-experimental and only 5 RCT studies. Multifactorial interventions were more common (n=18) than multicomponent (n=6), with the most frequent components including environmental adaptations and assistive aids (75% of studies). Meta-analyses provided evidence that both intervention types were effective at reducing the rate and risk of falls compared to usual care. Evidence was also obtained of greater reductions in rate and risk of falls with multicomponent interventions, however, analyses were potentially confounded by an association between intervention type and study design. Falls interventions routinely employed in hospitals can substantially reduce falls, however, no evidence was obtained in support of tailoring interventions to individual risk factors. Future high-quality RCTs are required that directly compare multicomponent and multifactorial interventions

Rounding, filleting and smoothing of implicit surfaces

© 2017 CAD Solutions, LLC We describe an approach for performing constant radius offsetting and the related operations of filleting, rounding and smoothing for implicit surfaces. The offsetting operation is used as the basic component for defining the remaining operations. These operations are important operations for any modelling system. While it is known how to perform these operations for parametric representation and polygon meshes, there is limited prior work for implicit surfaces and procedural volumetric objects. The proposed approach is based on repeatedly computing the distance to a given implicit surface and its offset surfaces. We illustrate the results obtained by this approach with several examples, including procedurally defined microstructures and CAD objects

Numerical Modeling of Conjugate Thermogravitational Convection in a Closed System with a Radiant Energy Source in Conditions of Convective-Radiative Heat Exchange at the External Boundary

Mathematical modeling of conjugate natural convection in a closed rectangular cavity with a radiant energy source in conditions of convective-radiative heat exchange at the external boundary was conducted. The radiant energy distribution was set by the Lambert’s law. Conduction and convection processes analysis showed that the air masses flow pattern is modified slightly over the time. The temperature increases in the gas cavity, despite the heat removal from the one of the external boundary. According to the results of the integral heat transfer analysis were established that the average Nusselt number (Nu[av]) increasing occurs up to [tau]=200 (dimensionless time). Further Nu[av] has changed insignificantly due to the temperature field equalization near the interfaces "gas – wall"

A 3D Fully Convolutional Neural Network With Top-Down Attention-Guided Refinement for Accurate and Robust Automatic Segmentation of Amygdala and Its Subnuclei

Recent advances in deep learning have improved the segmentation accuracy of subcortical brain structures, which would be useful in neuroimaging studies of many neurological disorders. However, most existing deep learning based approaches in neuroimaging do not investigate the specific difficulties that exist in segmenting extremely small but important brain regions such as the subnuclei of the amygdala. To tackle this challenging task, we developed a dual-branch dilated residual 3D fully convolutional network with parallel convolutions to extract more global context and alleviate the class imbalance issue by maintaining a small receptive field that is just the size of the regions of interest (ROIs). We also conduct multi-scale feature fusion in both parallel and series to compensate the potential information loss during convolutions, which has been shown to be important for small objects. The serial feature fusion enabled by residual connections is further enhanced by a proposed top-down attention-guided refinement unit, where the high-resolution low-level spatial details are selectively integrated to complement the high-level but coarse semantic information, enriching the final feature representations. As a result, the segmentations resulting from our method are more accurate both volumetrically and morphologically, compared with other deep learning based approaches. To the best of our knowledge, this work is the first deep learning-based approach that targets the subregions of the amygdala. We also demonstrated the feasibility of using a cycle-consistent generative adversarial network (CycleGAN) to harmonize multi-site MRI data, and show that our method generalizes well to challenging traumatic brain injury (TBI) datasets collected from multiple centers. This appears to be a promising strategy for image segmentation for multiple site studies and increased morphological variability from significant brain pathology

Measurement of the longitudinal and transverse cross-section in e^+e^- annihilation at sqrt(s)=35-44 GeV

An investigation of the polar angle distribution of charged hadrons is presented using data taken by the JADE experiment at the PETRA e^+e^- collider at centre-of-mass energies of 35 and 44 GeV. From fits to the polar angle distribution the longitudinal, sigma_L, and transverse, sigma_T, cross-section relative to the total hadronic are determined at an average energy scale of 36.6 GeV. The results are sigma_L/sigma_tot = 0.067 +/- 0.013, sigma_T/sigma_tot = 0.933 -/+ 0.013 where total errors are given and the results are exactly anti-correlated. Using the next-to-leading order QCD prediction for the longitudinal cross-section, the value alpha_S(36.6 GeV) = 0.150 +/- 0.025 of the strong coupling constant is obtained in agreement with the world average value of alpha_S evolved to an energy scale of 36.6 GeV.Comment: 12 pages, LaTeX2e, 5 .eps-files included, pennames.sty included, submitted to Phys. Lett.

Geometry of Frictionless and Frictional Sphere Packings

We study static packings of frictionless and frictional spheres in three dimensions, obtained via molecular dynamics simulations, in which we vary particle hardness, friction coefficient, and coefficient of restitution. Although frictionless packings of hard-spheres are always isostatic (with six contacts) regardless of construction history and restitution coefficient, frictional packings achieve a multitude of hyperstatic packings that depend on system parameters and construction history. Instead of immediately dropping to four, the coordination number reduces smoothly from $z=6$ as the friction coefficient $\mu$ between two particles is increased.Comment: 6 pages, 9 figures, submitted to Phys. Rev.

Anomalous tag diffusion in the asymmetric exclusion model with particles of arbitrary sizes

Anomalous behavior of correlation functions of tagged particles are studied in generalizations of the one dimensional asymmetric exclusion problem. In these generalized models the range of the hard-core interactions are changed and the restriction of relative ordering of the particles is partially brocken. The models probing these effects are those of biased diffusion of particles having size S=0,1,2,..., or an effective negative "size" S=-1,-2,..., in units of lattice space. Our numerical simulations show that irrespective of the range of the hard-core potential, as long some relative ordering of particles are kept, we find suitable sliding-tag correlation functions whose fluctuations growth with time anomalously slow ($t^{{1/3}}$), when compared with the normal diffusive behavior ($t^{{1/2}}$). These results indicate that the critical behavior of these stochastic models are in the Kardar-Parisi-Zhang (KPZ) universality class. Moreover a previous Bethe-ansatz calculation of the dynamical critical exponent $z$, for size $S \geq 0$ particles is extended to the case $S<0$ and the KPZ result $z=3/2$ is predicted for all values of $S \in {Z}$.Comment: 4 pages, 3 figure

The Bose-Einstein correlation function C2(Q)C_2(Q) from a Quantum Field Theory point of view

We show that a recently proposed derivation of Bose-Einstein correlations (BEC) by means of a specific version of thermal Quantum Field Theory (QFT), supplemented by operator-field evolution of the Langevin type, allows for a deeper understanding of the possible coherent behaviour of the emitting source and a clear identification of the origin of the observed shape of the BEC function $C_2(Q)$. Previous conjectures in this matter obtained by other approaches are confirmed and have received complementary explanation.Comment: Some misprints corrected. To be publishe in Phys. Rev.

Spectral and Transport Properties of d-Wave Superconductors With Strong Impurities

One of the remarkable features of disordered d-wave superconductors is strong sensitivity of long range properties to the microscopic realization of the disorder potential. Particularly rich phenomenology is observed for the -- experimentally relevant -- case of dilute distributions of isolated impurity centers. Building on earlier diagrammatic analyses, the present paper derives and analyses a low energy effective field theory of this system. Specifically, the results of previous diagrammatic T-matrix approaches are extended into the perturbatively inaccessible low energy regimes, and the long range (thermal) transport behaviour of the system is discussed. It turns out that in the extreme case of a half-filled tight binding band and infinitely strong impurities (impurities at the unitary limit), the system is in a delocalized phase.Comment: 14 pages, two figures include