Universal conductance fluctuations in non-integer dimensions

We propose an Ansatz for Universal conductance fluctuations in continuous dimensions from 0 up to 4. The Ansatz agrees with known formulas for integer dimensions 1, 2 and 3, both for hard wall and periodic boundary conditions. The method is based solely on the knowledge of energy spectrum and standard assumptions. We also study numerically the conductance fluctuations in 4D Anderson model, depending on system size L and disorder W. We find a small plateau with a value diverging logarithmically with increasing L. Universality gets lost just in 4D.Comment: 4 pages, 4 figures submitted to Phys. Rev.

Nonuniversal correlations in multiple scattering

We show that intensity of a wave created by a source embedded inside a three-dimensional disordered medium exhibits a non-universal space-time correlation which depends explicitly on the short-distance properties of disorder, source size, and dynamics of disorder in the immediate neighborhood of the source. This correlation has an infinite spatial range and is long-ranged in time. We suggest that a technique of "diffuse microscopy" might be developed employing spatially-selective sensitivity of the considered correlation to the disorder properties.Comment: 15 pages, 3 postscript figures, accepted to Phys. Rev.

Diffusive and localization behavior of electromagnetic waves in a two-dimensional random medium

In this paper, we discuss the transport phenomena of electromagnetic waves in a two-dimensional random system which is composed of arrays of electrical dipoles, following the model presented earlier by Erdogan, et al. (J. Opt. Soc. Am. B {\bf 10}, 391 (1993)). A set of self-consistent equations is presented, accounting for the multiple scattering in the system, and is then solved numerically. A strong localization regime is discovered in the frequency domain. The transport properties within, near the edge of and nearly outside the localization regime are investigated for different parameters such as filling factor and system size. The results show that within the localization regime, waves are trapped near the transmitting source. Meanwhile, the diffusive waves follow an intuitive but expected picture. That is, they increase with travelling path as more and more random scattering incurs, followed by a saturation, then start to decay exponentially when the travelling path is large enough, signifying the localization effect. For the cases that the frequencies are near the boundary of or outside the localization regime, the results of diffusive waves are compared with the diffusion approximation, showing less encouraging agreement as in other systems (Asatryan, et al., Phys. Rev. E {\bf 67}, 036605 (2003).)Comment: 8 pages 9 figure

Patient-driven healthcare recommendations for adults with esophageal atresia and their families

Background: Adults with esophageal atresia (EA) require a multidisciplinary follow-up approach, taking into account gastroesophageal problems, respiratory problems and psychosocial wellbeing. Too little is known about the full scope of these individuals’ healthcare needs. We aimed to map all medical and psychosocial needs of adults with EA and their family members, and to formulate healthcare recommendations for daily practice. Methods: A qualitative study was performed, using data from recorded semi-structured interviews with two focus groups, one consisting of adult patients with EA (n = 15) and one of their family members (n = 13). After verbatim transcription and computerized thematic analysis, results were organized according to the International Classification of Functioning, Disability and Health. Ethical approval had been obtained. Results: Healthcare needs were described through 74 codes, classified into 20 themes. Most important findings for patients included the impact of gastrointestinal and pulmonary problems on daily life, long-term emotional distress of patients and parents and the need of a standardized multidisciplinary follow-up program during both child- and adulthood. Conclusion: The focus groups revealed numerous physical and mental health problems, as well as social difficulties, that require attention from different healthcare providers. We have formulated several healthcare recommendations that physicians may use in long-term follow-up

Temporal fluctuations of waves in weakly nonlinear disordered media

We consider the multiple scattering of a scalar wave in a disordered medium with a weak nonlinearity of Kerr type. The perturbation theory, developed to calculate the temporal autocorrelation function of scattered wave, fails at short correlation times. A self-consistent calculation shows that for nonlinearities exceeding a certain threshold value, the multiple-scattering speckle pattern becomes unstable and exhibits spontaneous fluctuations even in the absence of scatterer motion. The instability is due to a distributed feedback in the system "coherent wave + nonlinear disordered medium". The feedback is provided by the multiple scattering. The development of instability is independent of the sign of nonlinearity.Comment: RevTeX, 15 pages (including 5 figures), accepted for publication in Phys. Rev.

A study on the robustness of two stiffened composite fuselage panels

The European Commission project COCOMAT aimed at exploiting the large reserve of strength in composite structures through more accurate prediction of collapse. As part of the research program, curved stiffened composite panels of various designs have been manufactured and tested in compression. In the current pool of experiments it is possible to observe the scatter in results caused by manufacturing defects and material variations. In a bid to account for the scatter in design, two qualitative measures of robustness, called Robust Indices, have been derived so that effective comparisons can be made. The first measure quantifies robustness of structures with respect to their input variables while the second measure quantifies the overall robustness of a structure

Collapse Analysis, Defect Sensitivity and Load Paths

An experimental program for collapse of curved stiffened composite shell structures encountered a wide range of initial and deep buckling mode shapes. This paper presents work to determine the significance of the buckling deformations for determining the final collapse loads and to understand the source of the variation. A finite element analysis is applied to predict growth of damage that causes the disbonding of stiffeners and defines a load displacement curve to final collapse. The variability in material properties and geometry is then investigated to identify a range of buckling modes and development of deep postbuckling deformation encountered in the experimental program. Finally the load paths for the damaged panels are used to visualise the load transfer and enhance the physical understanding of the load displacement history

Compositionality in synchronous dataflow: modular code generation from hierarchical SDF graphs

Hierarchical SDF models are not compositional: a composite SDF actor cannot be represented as an atomic SDF actor without loss of information that can lead to rate inconsistency or deadlock. Motivated by the need for incremental and modular code generation from hierarchical SDF models, we introduce in this paper DSSF profiles. DSSF (Deterministic SDF with Shared FIFOs) forms a compositional abstraction of composite actors that can be used for modular compilation. We provide algorithms for automatic synthesis of non-monolithic DSSF profiles of composite actors given DSSF profiles of their sub-actors. We show how different trade-offs can be explored when synthesizing such profiles, in terms of compactness (keeping the size of the generated DSSF profile small) versus reusability (maintaining necessary information to preserve rate consistency and deadlock-absence) as well as algorithmic complexity. We show that our method guarantees maximal reusability and report on a prototype implementation