Relational use of an electronic quality of life and practice support system in hospital palliative consult care: a pilot study

Objectives: This study is part of an overarching research initiative on the development and integration of an electronic Quality of Life and Practice Support System (QPSS) that uses patient-reported outcome and experience measures in clinical practice. The current study focused on palliative nurse consultants trialing the QPSS with older hospitalized adults receiving acute care. The primary aim of the study was to better understand consultants’ and patients’ experiences and perspectives of use. Method: The project involved two nurse specialists within a larger palliative outreach consult team (POCT) and consenting older adult patients (age 55+) in a large tertiary acute care hospital in western Canada. User-centered design of the QPSS was informed by three focus groups with the entire POCT team, and implementation was evaluated by direct observation as well as interviews with the POCT nurses and three patients. Thematic analysis of interviews and field notes was informed by theoretical perspectives from social sciences. Result: Over 9 weeks, the POCT nurses used the QPSS at least once with 20 patients, for a total of 47 administrations. The nurses most often assisted patients in using the QPSS. Participants referenced three primary benefits of relational use: enhanced communication, strengthened therapeutic relations, and cocreation of new insights about quality of life and care experiences. The nurses also reported increased visibility of quality of life concerns and positive development as relational care providers. Significance of results: Participants expressed that QPSS use positively influenced relations of care and enhanced practices consistent with person-centered care. Results also indicate that electronic assessment systems may, in some instances, function as actor-objects enabling new knowledge and relations of care rather than merely as a neutral technological platform. This is the first study to examine hospital palliative consult clinicians’ use of a tablet-based system for routine collection of patient-reported outcome and experience measures

Theory of Phonon-Assisted Multimagnon Optical Absorption and Bimagnon States in Quantum Antiferromagnets

We calculate the effective charge for multimagnon infrared (IR) absorption assisted by phonons in a perovskite like antiferromagnet and we compute the spectra for two magnon absorption using interacting spin-wave theory. The full set of equations for the interacting two magnon problem is presented in the random phase approximation for arbitrary total momentum of the magnon pair. The spin wave theory results fit very well the primary peak of recent measured bands in the parent insulating compounds of cuprate superconductors. The line shape is explained as being due to the absorption of one phonon plus a new quasiparticle excitation of the Heisenberg Hamiltonian that consists off a long lived virtual bound state of two magnons (bimagnon). The bimagnon states have well defined energy and momentum in a substantial portion of the Brillouin zone. The higher energy bands are explained as one phonon plus higher multimagnon absorption processes. Other possible experiments for observing bimagnons are proposed. In addition we predict the line shape for the spin one system La$_2$NiO$_4$.Comment: Modified version of the paper to be published in PR

First order algorithms in variational image processing

Variational methods in imaging are nowadays developing towards a quite universal and flexible tool, allowing for highly successful approaches on tasks like denoising, deblurring, inpainting, segmentation, super-resolution, disparity, and optical flow estimation. The overall structure of such approaches is of the form ${\cal D}(Ku) + \alpha {\cal R} (u) \rightarrow \min_u$ ; where the functional ${\cal D}$ is a data fidelity term also depending on some input data $f$ and measuring the deviation of $Ku$ from such and ${\cal R}$ is a regularization functional. Moreover $K$ is a (often linear) forward operator modeling the dependence of data on an underlying image, and $\alpha$ is a positive regularization parameter. While ${\cal D}$ is often smooth and (strictly) convex, the current practice almost exclusively uses nonsmooth regularization functionals. The majority of successful techniques is using nonsmooth and convex functionals like the total variation and generalizations thereof or $\ell_1$-norms of coefficients arising from scalar products with some frame system. The efficient solution of such variational problems in imaging demands for appropriate algorithms. Taking into account the specific structure as a sum of two very different terms to be minimized, splitting algorithms are a quite canonical choice. Consequently this field has revived the interest in techniques like operator splittings or augmented Lagrangians. Here we shall provide an overview of methods currently developed and recent results as well as some computational studies providing a comparison of different methods and also illustrating their success in applications.Comment: 60 pages, 33 figure

Harvesting Information from Captions for Weakly Supervised Semantic Segmentation

Since acquiring pixel-wise annotations for training convolutional neural networks for semantic image segmentation is time-consuming, weakly supervised approaches that only require class tags have been proposed. In this work, we propose another form of supervision, namely image captions as they can be found on the Internet. These captions have two advantages. They do not require additional curation as it is the case for the clean class tags used by current weakly supervised approaches and they provide textual context for the classes present in an image. To leverage such textual context, we deploy a multi-modal network that learns a joint embedding of the visual representation of the image and the textual representation of the caption. The network estimates text activation maps (TAMs) for class names as well as compound concepts, i.e. combinations of nouns and their attributes. The TAMs of compound concepts describing classes of interest substantially improve the quality of the estimated class activation maps which are then used to train a network for semantic segmentation. We evaluate our method on the COCO dataset where it achieves state of the art results for weakly supervised image segmentation

Magnon-mediated interactions between fermions depend strongly on the lattice structure

We propose two new methods to calculate exactly the spectrum of two spin-${1\over 2}$ charge carriers moving in a ferromagnetic background, at zero temperature. We find that if the spins are located on a different sublattice than that on which the fermions move, magnon-mediated effective interactions are very strong and can bind the fermions into low-energy bipolarons with triplet character. This never happens in models where spins and charge carriers share the same lattice, whether they are in the same band or in different bands. This proves that effective one-lattice models do not describe correctly the low-energy part of the two-carrier spectrum of a two-sublattice model, even though they may describe the low-energy single-carrier spectrum appropriately

High-spin polaron in lightly doped CuO2_2 planes

We device and investigate numerically a minimal yet detailed spin polaron model that describes lightly doped CuO$_2$ layers. The low-energy physics of a hole is studied by total-spin-resolved exact diagonalization on clusters of up to 32 CuO$_2$ unit cells, revealing features missed by previous studies. In particular, spin-polaron states with total spin 3/2 are the lowest eigenstates in several regions of the Brillouin zone. In these regions, and also at other points the quasiparticle weight is identically zero, indicating orthogonal states to those represented in the one electron Green's function. This highlights the importance of proper treatment of spin fluctuations in the many-body background.Comment: To appear in Phys. Rev. Lett. Final version and Supplementary Materials will be available at the journal's websit