High power spiral cavity quantum cascade superluminescent emitter.

Quantum Cascade devices with an emission wavelength centered around 5 µm have been shaped into compact, yet long (8 mm and 12 mm) spiral cavities to increase mid-infrared superluminescence (SL) power. Up to ~57 mW of SL power at 250 K is obtained with a Gaussian emission spectrum with a full width at half maximum of 56 cm(-1) and a coherence length of ~107 µm.

Scaling theory of heat transport in quasi-one-dimensional disordered harmonic chains.

We introduce a variant of the banded random matrix ensemble and show, using detailed numerical analysis and theoretical arguments, that the phonon heat current in disordered quasi-one-dimensional lattices obeys a one-parameter scaling law. The resulting ß function indicates that an anomalous Fourier law is applicable in the diffusive regime, while in the localization regime the heat current decays exponentially with the sample size. Our approach opens a new way to investigate the effects of Anderson localization in heat conduction based on the powerful ideas of scaling theory.

A qualitative study exploring the nurse telephone follow-up of patients returning home with a colostomy.

AIM: The aim of this study was to explore and describe the content of telephone intervention conversations conducted by an enterostomal nurse with patients discharged home with a colostomy. BACKGROUND: People discharged home with a new colostomy often encounter stoma-related difficulties. Postdischarge care with telephone follow-up by an enterostomal nurse is a helpful way to provide support for patients and ensure continuity of care. There is a paucity of studies reporting the content of telephone follow-up of colostomy patients. Information on the content of such follow-up is important in helping to formulate telephone call protocols that can help these patients. DESIGN: A qualitative exploratory study conducted in a university-based cancer centre in China. METHODS: The contents of 25 intervention phone calls to colostomy patients from January-August 2009 were subject to qualitative content analysis. RESULTS: Five themes emerged from the qualitative content analysis: 'education for stoma care', 'access to stoma care', 'encouraging stoma self-care', 'resuming normal living' and 'general postoperative problems'. CONCLUSIONS: Colostomy patients experienced stoma-related problems and difficulties after discharge, most of which could be effectively managed via telephone follow-up by an enterostomal nurse. The telephone follow-up satisfied patients' need for information and facilitated their adjustment to the permanent stoma. The findings suggested that patients had unmet needs after discharge and needed follow-up on returning home. RELEVANCE TO CLINICAL PRACTICE: This study provides important information to guide practice and education. The themes extracted from the qualitative content analysis provide a useful framework to guide the nurse in discussing care with the stoma patients and ensuring patients' adjustment to the permanent stoma. Further work can be done using this framework to develop protocols as standards of care and education materials when educating nurse specialists in stoma care.

Heat transport in active harmonic chains.

We show that a harmonic lattice model with amplifying and attenuating elements, when coupled to two thermal baths, exhibits unique heat transport properties. Some of these novel features include anomalous nonequilibrium steady-state heat currents, negative differential thermal conductance, as well as nonreciprocal heat transport. We find that when these elements are arranged in a PT-symmetric manner, the domain of existence of the nonequilibrium steady state is maximized. We propose an electronic experimental setup based on resistive-inductive-capacitive (RLC) transmission lines, where our predictions can be tested.

Probing localization in absorbing systems via Loschmidt echos.

We measure Anderson localization in quasi-one-dimensional waveguides in the presence of absorption by analyzing the echo dynamics due to small perturbations. We specifically show that the inverse participation number of localized modes dictates the decay of the Loschmidt echo, differing from the Gaussian decay expected for diffusive or chaotic systems. Our theory, based on a random matrix modeling, agrees perfectly with scattering echo measurements on a quasi-one-dimensional microwave cavity filled with randomly distributed scatterers.