Impurity scattering and transport of fractional Quantum Hall edge state

We study the effects of impurity scattering on the low energy edge state dynamic s for a broad class of quantum Hall fluids at filling factor $\nu =n/(np+1)$, for integer $n$ and even integer $p$. When $p$ is positive all $n$ of the edge modes are expected to move in the same direction, whereas for negative $p$ one mode moves in a direction opposite to the other $n-1$ modes. Using a chiral-Luttinger model to describe the edge channels, we show that for an ideal edge when $p$ is negative, a non-quantized and non-universal Hall conductance is predicted. The non-quantized conductance is associated with an absence of equilibration between the $n$ edge channels. To explain the robust experimental Hall quantization, it is thus necessary to incorporate impurity scattering into the model, to allow for edge equilibration. A perturbative analysis reveals that edge impurity scattering is relevant and will modify the low energy edge dynamics. We describe a non-perturbative solution for the random $n-$channel edge, which reveals the existence of a new disorder-dominated phase, characterized by a stable zero temperature renormalization group fixed point. The phase consists of a single propagating charge mode, which gives a quantized Hall conductance, and $n-1$ neutral modes. The neutral modes all propagate at the same speed, and manifest an exact SU(n) symmetry. At finite temperatures the SU(n) symmetry is broken and the neutral modes decay with a finite rate which varies as $T^2$ at low temperatures. Various experimental predictions and implications which follow from the exact solution are described in detail, focusing on tunneling experiments through point contacts.Comment: 19 pages (two column), 5 post script figures appended, 3.0 REVTE

Conceptual Disorganization Weakens Links in Cognitive Pathways: Disentangling Neurocognition, Social Cognition, and Metacognition in Schizophrenia

Disentangling links between neurocognition, social cognition, and metacognition offers the potential to improve interventions for these cognitive processes. Disorganized symptoms have shown promise for explaining the limiting relationship that neurocognition holds with both social cognition and metacognition. In this study, primary aims included: 1) testing whether conceptual disorganization, a specific disorganized symptom, moderated relationships between cognitive processes, and 2) examining the level of conceptual disorganization necessary for links between cognitive processes to break down. To accomplish these aims, comprehensive assessments of conceptual disorganization, neurocognition, social cognition, and metacognition were administered to 67 people with schizophrenia-spectrum disorders. We found that conceptual disorganization significantly moderated the relationship between neurocognition and metacognition, with links between cognitive processes weakening when conceptual disorganization is present even at minimal levels of severity. There was no evidence that conceptual disorganization—or any other specific disorganized symptom—drove the limiting relationship of neurocognition on social cognition. Based on our findings, conceptual disorganization appears to be a critical piece of the puzzle when disentangling the relationship between neurocognition and metacognition. Roles of specific disorganized symptoms in the neurocognition – social cognition relationship were less clear. Findings from this study suggest that disorganized symptoms are an important treatment consideration when aiming to improve cognitive impairments

Low Raman-noise correlated photon-pair generation in a dispersion-engineered chalcogenide As2S3 planar waveguide

We demonstrate low Raman-noise correlated photon-pair generation in a dispersion-engineered 10 mm As2S3 chalcogenide waveguide at room temperature. We show a coincidence-to-accidental ratio (CAR) of 16.8, a 250 times increase compared with previously published results in a chalcogenide waveguide, with a corresponding brightness of 3×105  pairs·s−1·nm−1 generated at the chip. Dispersion engineering of our waveguide enables photon passbands to be placed in the low spontaneous Raman scattering (SpRS) window at 7.4 THz detuning from the pump. This Letter shows the potential for As2S3 chalcogenide to be used for nonlinear quantum photonic devices.This work was supported by the Centre of Excellence, Federation Fellowship, and Discovery Early Career Researcher Award (DECRA) programs of the Australian Research Council (ARC). The Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) is an ARC Centre of Excellence (project number CE110001018)

Adding Spin Functionality to Traditional Optoelectronics via Chiral Perovskite

Spin polarized current generation and injection into semiconductors at room temperature are key to enable a broader range of opto-spintronic functionalities, yet the inherent efficiency of spin injection across commonly used semiconductor-ferromagnet interfaces is limited. Here, we demonstrate efficient spin injection into commercially viable III-V light emitting diodes (LED) by integrating chiral halide perovskite layers with (AlxGa1-x)0.5In0.5P multiple quantum wells (MQW). Spin polarized current is injected via chirality induced spin selectivity (CISS) and the spin accumulation in the III-V semiconductor is detected via the emission of circularly polarized light with a degree of circular polarization of up to ~ 15%. X-ray photoemission spectroscopy (XPS) and transmission electron microscopy (TEM) cross sectional imaging indicate a pristine perovskite/III-V interface. These findings demonstrate chiral perovskite semiconductors transform well-developed semiconductor platforms to enable control over spin, charge, and light

Palliative care early in the care continuum among patients with serious respiratory illness an official ATS/AAHPM/HPNA/SWHPN policy statement

Background: Patients with serious respiratory illness and their caregivers suffer considerable burdens, and palliative care is a fundamental right for anyone who needs it. However, the overwhelming majority of patients do not receive timely palliative care before the end of life, despite robust evidence for improved outcomes. Goals: This policy statement by the American Thoracic Society (ATS) and partnering societies advocates for improved integration of high-quality palliative care early in the care continuum for patients with serious respiratory illness and their caregivers and provides clinicians and policymakers with a framework to accomplish this. Methods: An international and interprofessional expert committee, including patients and caregivers, achieved consensus across a diverse working group representing pulmonary–critical care, palliative care, bioethics, health law and policy, geriatrics, nursing, physiotherapy, social work, pharmacy, patient advocacy, psychology, and sociology. Results: The committee developed fundamental values, principles, and policy recommendations for integrating palliative care in serious respiratory illness care across seven domains: 1) delivery models, 2) comprehensive symptom assessment and management, 3) advance care planning and goals of care discussions, 4) caregiver support, 5) health disparities, 6) mass casualty events and emergency preparedness, and 7) research priorities. The recommendations encourage timely integration of palliative care, promote innovative primary and secondary or specialist palliative care delivery models, and advocate for research and policy initiatives to improve the availability and quality of palliative care for patients and their caregivers. Conclusions: This multisociety policy statement establishes a framework for early palliative care in serious respiratory illness and provides guidance for pulmonary–critical care clinicians and policymakers for its proactive integration

Mechanism and evolution of the Zn-fingernail required for interaction of VARP with VPS29

Funder: Discovery Grants from the Natural Sciences and Engineering Research Council of Canada (RES0043758, RES0046091)Abstract: VARP and TBC1D5 are accessory/regulatory proteins of retromer-mediated retrograde trafficking from endosomes. Using an NMR/X-ray approach, we determined the structure of the complex between retromer subunit VPS29 and a 12 residue, four-cysteine/Zn++ microdomain, which we term a Zn-fingernail, two of which are present in VARP. Mutations that abolish VPS29:VARP binding inhibit trafficking from endosomes to the cell surface. We show that VARP and TBC1D5 bind the same site on VPS29 and can compete for binding VPS29 in vivo. The relative disposition of VPS29s in hetero-hexameric, membrane-attached, retromer arches indicates that VARP will prefer binding to assembled retromer coats through simultaneous binding of two VPS29s. The TBC1D5:VPS29 interaction is over one billion years old but the Zn-fingernail appears only in VARP homologues in the lineage directly giving rise to animals at which point the retromer/VARP/TBC1D5 regulatory network became fully established

In vivo measurement of skin surface strain and sub-surface layer deformation induced by natural tissue stretching.

Stratum corneum and epidermal layers change in terms of thickness and roughness with gender, age and anatomical site. Knowledge of the mechanical and tribological properties of skin associated with these structural changes are needed to aid in the design of exoskeletons, prostheses, orthotics, body mounted sensors used for kinematics measurements and in optimum use of wearable on-body devices. In this case study, optical coherence tomography (OCT) and digital image correlation (DIC) were combined to determine skin surface strain and sub-surface deformation behaviour of the volar forearm due to natural tissue stretching. The thickness of the epidermis together with geometry changes of the dermal-epidermal junction boundary were calculated during change in the arm angle, from flexion (90°) to full extension (180°). This posture change caused an increase in skin surface Lagrange strain, typically by 25% which induced considerable morphological changes in the upper skin layers evidenced by reduction of epidermal layer thickness (20%), flattening of the dermal-epidermal junction undulation (45-50% reduction of flatness being expressed as Ra and Rz roughness profile height change) and reduction of skin surface roughness Ra and Rz (40-50%). The newly developed method, DIC combined with OCT imaging, is a powerful, fast and non-invasive methodology to study structural skin changes in real time and the tissue response provoked by mechanical loading or stretching