21,779 research outputs found

    Entanglement of a qubit with a single oscillator mode

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    We solve a model of a qubit strongly coupled to a massive environmental oscillator mode where the qubit backaction is treated exactly. Using a Ginzburg-Landau formalism, we derive an effective action for this well known localization transition. An entangled state emerges as an instanton in the collective qubit-environment degree of freedom and the resulting model is shown to be formally equivalent to a Fluctuating Gap Model (FGM) of a disordered Peierls chain. Below the transition, spectral weight is transferred to an exponentially small energy scale leaving the qubit coherent but damped. Unlike the spin-boson model, coherent and effectively localized behaviors may coexist.Comment: 4 pages, 1 figure; added calculation of entanglement entrop

    Accounting for Intellectual Property: inconsistencies and challenges

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    The recognition of the rights attached to some forms of intellectual property is a contested domain in legal frameworks, such as the Trade Related Aspects of Intellectual Property Rights Agreement. The same can be said of economic frameworks, such as accounting which attempt to recognise and value intellectual property for the purposes of providing information for decision making. In this paper we explore the discourse of accounting in the recognition of intellectual property as an asset according to the new International Accounting Standards. We then contrast the legal and accounting discourses in which intellectual property rights are acknowledged, concluding that these discourses are not necessarily aligned. The effects and implications of the development of a global regime for accounting for intangibles may eventually harmonise the accounting treatment for intellectual property but does not resolve the contentious issue of the inconsistencies in the recognition of intellectual property rights under different frameworks and the implications for economic decision making

    Evidence of environmental strains on charge injection in silole based organic light emitting diodes

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    Using d. functional theory (DFT) computations, the authors demonstrated a substantial skeletal relaxation when the structure of 2,5-bis-[4-anthracene-9-yl-phenyl]-1,1-dimethyl-3,4-diphenyl-silole (BAS) is optimized in the gas-phase comparing with the mol. structure detd. from monocrystal x-ray diffraction. The origin of such a relaxation is explained by a strong environmental strains induced by the presence of anthracene entities. Also, the estn. of the frontier orbital levels showed that this structural relaxation affects mainly the LUMO that is lowered of 190 meV in the gas phase. To check if these theor. findings would be confirmed for thin films of BAS, the authors turned to UV photoemission spectroscopy and/or inverse photoemission spectroscopy and electrooptical measurements. The study of the c.d. or voltage and luminance or voltage characteristics of an ITO/PEDOT/BAS/Au device clearly demonstrated a very unusual temp.-dependent behavior. Using a thermally assisted tunnel transfer model, this behavior likely originated from the variation of the electronic affinity of the silole deriv. with the temp. The thermal agitation relaxes the mol. strains in thin films as it is shown when passing from the cryst. to the gas phase. The relaxation of the intramol. thus induces an increase of the electronic affinity and, as a consequence, the more efficient electron injection in org. light-emitting diodes

    Competitive Dairy Value Chains in Southeast Asia – Part II : Dairy Expert Roundtable Meeting, December 8 & 9, 2010, Muak Lek, Thailand

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    The regional Dairy Expert Roundtable Meeting on “Competitive Dairy Value Chains in Southeast Asia” provided a forum for participants from six Southeast Asian countries to discuss how dairy value chains in this region can become more competitive and sustainable. The demand for dairy products in these countries is increasing steadily. Countries rely more and more on imports. Inefficiencies in the chain, low productivity, quality issues, as well as institutional obstacles make locally produced dairy products less competitive. International developments, national policies and experiences, lessons learned, and challenges in the value chain were presented and discussed during the meeting. Many countries in the region face similar challenges. Solutions depend much on the local context. Better exchange of experiences and knowledge among the Southeast Asian countries can contribute to more efficient local dairy value chains. This document, Part II, contains the PowerPoint presentations from the workshop and is an annex to the main report (Part I) of the meeting

    Mapping individual electromagnetic field components inside a photonic crystal

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    We present a method to map the absolute electromagnetic field strength inside photonic crystals. We apply the method to map the electric field component Ez of a two-dimensional photonic crystal slab at microwave frequencies. The slab is placed between two mirrors to select Bloch standing waves and a subwavelength spherical scatterer is scanned inside the resulting resonator. The resonant Bloch frequencies shift depending on the electric field at the position of the scatterer. To map the electric field component Ez we measure the frequency shift in the reflection and transmission spectrum of the slab versus the scatterer position. Very good agreement is found between measurements and calculations without any adjustable parameters.Comment: 12 pages, 7 figure

    Heavy-tailed kernels reveal a finer cluster structure in t-SNE visualisations

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    T-distributed stochastic neighbour embedding (t-SNE) is a widely used data visualisation technique. It differs from its predecessor SNE by the low-dimensional similarity kernel: the Gaussian kernel was replaced by the heavy-tailed Cauchy kernel, solving the "crowding problem" of SNE. Here, we develop an efficient implementation of t-SNE for a tt-distribution kernel with an arbitrary degree of freedom ν\nu, with ν\nu\to\infty corresponding to SNE and ν=1\nu=1 corresponding to the standard t-SNE. Using theoretical analysis and toy examples, we show that ν<1\nu<1 can further reduce the crowding problem and reveal finer cluster structure that is invisible in standard t-SNE. We further demonstrate the striking effect of heavier-tailed kernels on large real-life data sets such as MNIST, single-cell RNA-sequencing data, and the HathiTrust library. We use domain knowledge to confirm that the revealed clusters are meaningful. Overall, we argue that modifying the tail heaviness of the t-SNE kernel can yield additional insight into the cluster structure of the data

    Heavy Carriers and Non-Drude Optical Conductivity in MnSi

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    Optical properties of the weakly helimagnetic metal MnSi have been determined in the photon energy range from 2 meV to 4.5 eV using the combination of grazing incidence reflectance at 80 degrees (2 meV to 0.8 eV) and ellipsometry (0.8 to 4.5 eV). As the sample is cooled below 100 K the effective mass becomes strongly frequency dependent at low frequencies, while the scattering rate developes a linear frequency dependence. The complex optical conductivity can be described by the phenomenological relation \sigma(\omega,T) \propto (\Gamma(T)+i\omega)^{-1/2} used for cuprates and ruthenates.Comment: 5 pages, ReVTeX 4, 5 figures in eps forma

    Mild Traumatic Brain Injury in Elderly Patients Receiving Direct Oral Anticoagulants:A Systematic Review and Meta-Analysis

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    The aim of this work was to conduct a systematic review and meta-analysis of studies reporting on the risk of traumatic intracerebral hemorrhage (tICH), the course of tICH, and its treatment and mortality rates in elderly mild traumatic brain injury (mTBI) patients using direct oral anticoagulants (DOACs). We consulted PubMed and Embase for relevant cohort and case-control studies with a control group. Two authors independently selected studies, assessed methodological quality, and extracted outcome data. Estimates were pooled with the Mantel-Haenszel random-effects method. We identified 16 articles comprising 3671 elderly mTBI patients using DOACs. Use of DOACs was associated with a reduced risk of tICH compared to the use of vitamin K antagonists (VKAs; odds ratio [OR], 0.44; 95% confidence interval [CI], 0.29-0.65; I2 = 22%) and a similar risk compared to the use of antiplatelet therapy (APT; OR, 0.98; 95% CI, 0.39-2.44; I2 = 0%). Reversal agent use and neurosurgical intervention rate were lower in patients using DOACs compared to patients using VKAs (OR, 0.10; 95% CI, 0.06-0.16; I2 = 0% and OR, 0.37; 95% CI, 0.21-0.67; I2 = 0%, respectively). There was no significant difference in neurosurgical intervention rate between patients who used DOACs versus patients who used APT (OR, 0.58; 95% CI, 0.15-2.21; I2 = 41%) or no antithrombotic therapy (OR, 0.76; 95% CI, 0.20-2.86; I2 = 23%). ICH progression, risk of delayed ICH, and TBI-related in-hospital mortality were comparable among treatment groups. The present study indicates that elderly patients using DOACs have a lower risk of adverse outcome compared to patients using VKAs and a similar risk compared to patients using APT after mTBI

    Superfluid-insulator transition of the Josephson junction array model with commensurate frustration

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    We have studied the rationally frustrated Josephson-junction array model in the square lattice through Monte Carlo simulations of (2+1)(2+1)D XY-model. For frustration f=1/4f=1/4, the model at zero temperature shows a continuous superfluid-insulator transition. From the measurement of the correlation function and the superfluid stiffness, we obtain the dynamical critical exponent z=1.0z=1.0 and the correlation length critical exponent ν=0.4±0.05\nu=0.4 \pm 0.05. While the dynamical critical exponent is the same as that for cases f=0f=0, 1/2, and 1/3, the correlation length critical exponent is surprisingly quite different. When f=1/5f=1/5, we have the nature of a first-order transition.Comment: RevTex 4, to appear in PR

    Using smartphone-based ecological momentary assessment and personalized feedback for patients with chronic cancer-related fatigue:A proof-of-concept study

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    Introduction Chronic cancer-related fatigue (CCRF) is a complex multidimensional problem warranting person-centered care. Providing patients and therapists personalized feedback based on network analysis applied to ecological momentary assessment (EMA) data could facilitate case conceptualization in psycho-oncological care. The aim was to explore patients' and therapists' experiences of using an EMA app and personalized feedback based on network theory to aid case conceptualization in psycho-oncological care. Methods A n = 5 proof-of-concept study was implemented in routine psycho-oncological care. We purposively selected adult cancer patients suffering from severe CCRF who were on the waitlist for psycho-oncological care. During a 3-week period participants filled out the EMA app Energy InSight (fatigue, mood, activity, responding, and context) five times a day. Participants received a descriptive and network feedback report, which they reflected upon during the first therapy sessions. Thematic analysis was used to analyze user experiences. Results Patients experienced that filling out the Energy InSight app, as well as receiving descriptive and network-based personalized feedback provided them with insight into their CCRF. Although therapists experienced the discussion of network feedback as challenging, it facilitated the case conceptualization. Discussion Using EMA during waitlist for psychological care seemed feasible. Patients experienced beneficial effects from filling out the EMA app and talking over the personalized feedback reports, which in turn aided case conceptualization and personalized care. Based on this evaluation, an improved version of the Energy InSight app and a therapist training for providing network feedback is developed for implementation in psycho-oncological care
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