2,194 research outputs found

    Single-attribute utility analysis may be futile, but this can't be the end of the story: causal chain analysis as an aternative

    Full text link
    Research on providing single‐attribute utility analysis has shown moderate or even negative effects on the acceptance of selection and training tests by human resource decision makers. In this study, we contrasted the perceived utility of single‐attribute utility analysis with causal chain analysis as an alternative way of conducting utility analysis. Causal chain analysis focuses on measuring the linkages between HRM interventions and organizational outcomes mediated by employee attitudes and customer perceptions. We compared 144 managers' reactions to both methods of utility analysis concerning the variables understandability, information quality, perceived usefulness, user information satisfaction, and intention to use. Causal chain analysis yielded higher results than single‐attribute analysis for these variables, and a compound measure of these constructs supported this finding. This indicates that causal chain analysis is a valuable alternative method of communicating the utility of HRM interventions

    Theory of Spin Relaxation in Two-Electron Lateral Coupled Si/SiGe Quantum Dots

    Get PDF
    Highly accurate numerical results of phonon-induced two-electron spin relaxation in silicon double quantum dots are presented. The relaxation, enabled by spin-orbit coupling and the nuclei of 29^{29}Si (natural or purified abundance), are investigated for experimentally relevant parameters, the interdot coupling, the magnetic field magnitude and orientation, and the detuning. We calculate relaxation rates for zero and finite temperatures (100 mK), concluding that our findings for zero temperature remain qualitatively valid also for 100 mK. We confirm the same anisotropic switch of the axis of prolonged spin lifetime with varying detuning as recently predicted in GaAs. Conditions for possibly hyperfine-dominated relaxation are much more stringent in Si than in GaAs. For experimentally relevant regimes, the spin-orbit coupling, although weak, is the dominant contribution, yielding anisotropic relaxation rates of at least two order of magnitude lower than in GaAs.Comment: 11 pages, 10 figure

    Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas

    Full text link
    The coupling of the spin of electrons to their motional state lies at the heart of recently discovered topological phases of matter. Here we create and detect spin-orbit coupling in an atomic Fermi gas, a highly controllable form of quantum degenerate matter. We reveal the spin-orbit gap via spin-injection spectroscopy, which characterizes the energy-momentum dispersion and spin composition of the quantum states. For energies within the spin-orbit gap, the system acts as a spin diode. To fully inhibit transport, we open an additional spin gap, thereby creating a spin-orbit coupled lattice whose spinful band structure we probe. In the presence of s-wave interactions, such systems should display induced p-wave pairing, topological superfluidity, and Majorana edge states

    Accurate quadratic-response approximation for the self-consistent pseudopotential of semiconductor nanostructures

    Full text link
    Quadratic-response theory is shown to provide a conceptually simple but accurate approximation for the self-consistent one-electron potential of semiconductor nanostructures. Numerical examples are presented for GaAs/AlAs and InGaAs/InP (001) superlattices using the local-density approximation to density-functional theory and norm-conserving pseudopotentials without spin-orbit coupling. When the reference crystal is chosen to be the virtual-crystal average of the two bulk constituents, the absolute error in the quadratic-response potential for Gamma(15) valence electrons is about 2 meV for GaAs/AlAs and 5 meV for InGaAs/InP. Low-order multipole expansions of the electron density and potential response are shown to be accurate throughout a small neighborhood of each reciprocal lattice vector, thus providing a further simplification that is confirmed to be valid for slowly varying envelope functions. Although the linear response is about an order of magnitude larger than the quadratic response, the quadratic terms are important both quantitatively (if an accuracy of better than a few tens of meV is desired) and qualitatively (due to their different symmetry and long-range dipole effects).Comment: 16 pages, 20 figures; v2: new section on limitations of theor

    Systemic Immune-Inflammation Index (SII) Predicts Poor Survival in Pancreatic Cancer Patients Undergoing Resection

    Get PDF
    Background: The systemic immune-inflammation index based on peripheral neutrophil, lymphocyte, and platelet counts has shown a prognostic impact in several malignancies. The aim of this study was to determine the prognostic role of systemic immune-inflammation index in patients with pancreatic ductal adenocarcinoma undergoing resection. Methods: Consecutive patients who underwent surgical resection at the department of surgery at the Medical University of Vienna between 1995 and 2014 were included into this study. The systemic immune-inflammation index was calculated by the formula platelet*neutrophil/lymphocyte. Optimal cutoffs were determined using Youden's index. Uni-and multivariate analyses were calculated by the Cox proportional hazard regression model for overall survival. Results Three hundred twenty-one patients were included in this study. Clinical data was achieved from a prospective patient database. In univariate survival analysis, elevated systemic immune-inflammation index was found to be significantly associated with shortened patients' overall survival (p = 0.007). In multivariate survival analysis, systemic immune-inflammation index remained an independent prognostic factor for overall survival (p = 0.004). No statistical significance could be found for platelet to lymphocyte ratio and neutrophil to lymphocyte ratio in multivariate analysis. Furthermore, area under the curve analysis showed a higher prognostic significance for systemic immune-inflammation index, compared to platelet to lymphocyte ratio and neutrophil to lymphocyte ratio. Conclusion: A high systemic immune-inflammation index is an independent, preoperative available prognostic factor in patients with resectable pancreatic ductal adenocarcinoma and is superior to platelet to lymphocyte ratio and neutrophil to lymphocyte ratio for predicting overall survival in pancreatic ductal adenocarcinoma patients

    Highly anisotropic g-factor of two-dimensional hole systems

    Full text link
    Coupling the spin degree of freedom to the anisotropic orbital motion of two-dimensional (2D) hole systems gives rise to a highly anisotropic Zeeman splitting with respect to different orientations of an in-plane magnetic field B relative to the crystal axes. This mechanism has no analogue in the bulk band structure. We obtain good, qualitative agreement between theory and experimental data, taken in GaAs 2D hole systems grown on (113) substrates, showing the anisotropic depopulation of the upper spin subband as a function of in-plane B.Comment: 4 pages, 3 figure

    Activation of Sphingomyelinase-Ceramide-Pathway in COVID-19 Purposes Its Inhibition for Therapeutic Strategies

    Get PDF
    Effective treatment strategies for severe coronavirus disease (COVID-19) remain scarce. Hydrolysis of membrane-embedded, inert sphingomyelin by stress responsive sphingomyelinases is a hallmark of adaptive responses and cellular repair. As demonstrated in experimental and observational clinical studies, the transient and stress-triggered release of a sphingomyelinase, SMPD1, into circulation and subsequent ceramide generation provides a promising target for FDA-approved drugs. Here, we report the activation of sphingomyelinase-ceramide pathway in 23 intensive care patients with severe COVID-19. We observed an increase of circulating activity of sphingomyelinase with subsequent derangement of sphingolipids in serum lipoproteins and from red blood cells (RBC). Consistent with increased ceramide levels derived from the inert membrane constituent sphingomyelin, increased activity of acid sphingomyelinase (ASM) accurately distinguished the patient cohort undergoing intensive care from healthy controls. Positive correlational analyses with biomarkers of severe clinical phenotype support the concept of an essential pathophysiological role of ASM in the course of SARS-CoV-2 infection as well as of a promising role for functional inhibition with anti-inflammatory agents in SARS-CoV-2 infection as also proposed in independent observational studies. We conclude that large-sized multicenter, interventional trials are now needed to evaluate the potential benefit of functional inhibition of this sphingomyelinase in critically ill patients with COVID-19

    Bridging animal and clinical research during SARS-CoV-2 pandemic: A new-old challenge

    Get PDF
    Model animal; COVID-19; Recerca preclínicaModelo animal; COVID-19; Investigación preclínicaAnimal model; COVID-19; Pre-clinical researchMany milestones in medical history rest on animal modeling of human diseases. The SARS-CoV-2 pandemic has evoked a tremendous investigative effort primarily centered on clinical studies. However, several animal SARS-CoV-2/COVID-19 models have been developed and pre-clinical findings aimed at supporting clinical evidence rapidly emerge. In this review, we characterize the existing animal models exposing their relevance and limitations as well as outline their utility in COVID-19 drug and vaccine development. Concurrently, we summarize the status of clinical trial research and discuss the novel tactics utilized in the largest multi-center trials aiming to accelerate generation of reliable results that may subsequently shape COVID-19 clinical treatment practices. We also highlight areas of improvement for animal studies in order to elevate their translational utility. In pandemics, to optimize the use of strained resources in a short time-frame, optimizing and strengthening the synergy between the preclinical and clinical domains is pivotal

    Photon pressure induced test mass deformation in gravitational-wave detectors

    Get PDF
    A widely used assumption within the gravitational-wave community has so far been that a test mass acts like a rigid body for frequencies in the detection band, i.e. for frequencies far below the first internal resonance. In this article we demonstrate that localized forces, applied for example by a photon pressure actuator, can result in a non-negligible elastic deformation of the test masses. For a photon pressure actuator setup used in the gravitational wave detector GEO600 we measured that this effect modifies the standard response function by 10% at 1 kHz and about 100% at 2.5 kHz
    corecore