6,675 research outputs found

    Optically activated magnetic recording tape

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    Optically activated data storage medium visually and electromagnetically reproduces a recorded signal. In an electric field, particles in heat-fluidized thermoplastic layer form a visible image of the recorded signal. Refluidizing the thermoplastic layer erases the signals. Very high data packing densities are achieved

    A bifibrational reconstruction of Lawvere's presheaf hyperdoctrine

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    Combining insights from the study of type refinement systems and of monoidal closed chiralities, we show how to reconstruct Lawvere's hyperdoctrine of presheaves using a full and faithful embedding into a monoidal closed bifibration living now over the compact closed category of small categories and distributors. Besides revealing dualities which are not immediately apparent in the traditional presentation of the presheaf hyperdoctrine, this reconstruction leads us to an axiomatic treatment of directed equality predicates (modelled by hom presheaves), realizing a vision initially set out by Lawvere (1970). It also leads to a simple calculus of string diagrams (representing presheaves) that is highly reminiscent of C. S. Peirce's existential graphs for predicate logic, refining an earlier interpretation of existential graphs in terms of Boolean hyperdoctrines by Brady and Trimble. Finally, we illustrate how this work extends to a bifibrational setting a number of fundamental ideas of linear logic.Comment: Identical to the final version of the paper as appears in proceedings of LICS 2016, formatted for on-screen readin

    In Defense of the Bankruptcy Code\u27s Radical Integration of the Preference Rules Affecting Commercial Financing

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    The passage of the Bankruptcy Reform Act of 1978 significantly changed the statutory foundation of American preference law. Section 547 mixes new, carefully measured concepts with familiar definitional language from old section 60. The new conceptual structure of section 547 is a departure from the abstract framework of its predecessor. Under section 60, worthy transfers were protected by qualifications imaginatively grafted by the judges onto the specific elements of the preference definition. Among the most ingenious, and perhaps most significant, of these qualifications were those designed to protect pre-petition transfers incident to various types of financing arrangements. In contrast, section 547 of the Bankruptcy Code (Code) is a new and radical integration of definition and exception. The exceptions are separately listed in the statute and are not codifications of old case law qualifications. The new statutory test clearly displaces the old approach to worthy transfers. The use of section 60 language in the 547(b) definition of a preference, however, makes the vitality of old case law qualifications of this language an open question. The role of this case law in the new integration is a general concern that runs throughout the following discussion. Another general concern is the mechanics of the new integration when transfers normally incident to commercial financing are involved. What is the proper relationship between definition and exception in the new integration? How do the separate exceptions which may affect commercial financing relate to one another? Although the language of each exception suggests an isolated application, in a typical commercial financing arrangement several exceptions may be brought into play. This Article systematically examines the many specific problems within these broad topic areas in an effort to provide helpful solutions

    Electrometry Using Coherent Exchange Oscillations in a Singlet-Triplet-Qubit

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    Two level systems that can be reliably controlled and measured hold promise in both metrology and as qubits for quantum information science (QIS). When prepared in a superposition of two states and allowed to evolve freely, the state of the system precesses with a frequency proportional to the splitting between the states. In QIS,this precession forms the basis for universal control of the qubit,and in metrology the frequency of the precession provides a sensitive measurement of the splitting. However, on a timescale of the coherence time, T2T_2, the qubit loses its quantum information due to interactions with its noisy environment, causing qubit oscillations to decay and setting a limit on the fidelity of quantum control and the precision of qubit-based measurements. Understanding how the qubit couples to its environment and the dynamics of the noise in the environment are therefore key to effective QIS experiments and metrology. Here we show measurements of the level splitting and dephasing due to voltage noise of a GaAs singlet-triplet qubit during exchange oscillations. Using free evolution and Hahn echo experiments we probe the low frequency and high frequency environmental fluctuations, respectively. The measured fluctuations at high frequencies are small, allowing the qubit to be used as a charge sensor with a sensitivity of 2×108e/Hz2 \times 10^{-8} e/\sqrt{\mathrm{Hz}}, two orders of magnitude better than the quantum limit for an RF single electron transistor (RF-SET). We find that the dephasing is due to non-Markovian voltage fluctuations in both regimes and exhibits an unexpected temperature dependence. Based on these measurements we provide recommendations for improving T2T_2 in future experiments, allowing for higher fidelity operations and improved charge sensitivity

    Tensor products of subspace lattices and rank one density

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    We show that, if MM is a subspace lattice with the property that the rank one subspace of its operator algebra is weak* dense, LL is a commutative subspace lattice and PP is the lattice of all projections on a separable infinite dimensional Hilbert space, then the lattice LMPL\otimes M\otimes P is reflexive. If MM is moreover an atomic Boolean subspace lattice while LL is any subspace lattice, we provide a concrete lattice theoretic description of LML\otimes M in terms of projection valued functions defined on the set of atoms of MM. As a consequence, we show that the Lattice Tensor Product Formula holds for \Alg M and any other reflexive operator algebra and give several further corollaries of these results.Comment: 15 page

    Zero bias anomaly out of equilibrium

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    The non-equilibrium zero bias anomaly (ZBA) in the tunneling density of states of a diffusive metallic film is studied. An effective action describing virtual fluctuations out-of-equilibrium is derived. The singular behavior of the equilibrium ZBA is smoothed out by real processes of inelastic scattering.Comment: 4 page

    GOING FULL CIRCLE: AN ANALYSIS OF END-USER PERSPECTIVES ON THE IMPLEMENTATION OF THE USMC 360-DEGREE FEEDBACK PROGRAM

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    The United States Marine Corps’ counseling and development process requires modernization to remain on the leading edge of talent management and to keep pace with both the public sector and the private sector. The Commandant’s plan, titled Talent Management 2030, states that the Marine Corps will implement a 360-degree feedback program to bridge gaps and to retain the best, brightest, and most capable leaders. The purpose of our research is to analyze end-user perspectives to gauge support for 360-degree feedback in both developmental and evaluative capacities and offer recommendations for who should receive feedback and/or when feedback should be distributed. The sample population for our survey study is comprised of Marine Officers assigned to the Naval Postgraduate School. Most of the sample population consists of captains and majors between the ages of 26 and 35, with 6 to 15 years of military service. The results of our survey suggest that there is support for 360-degree feedback, particularly when utilized in a developmental capacity. Our analysis suggests that 360-degree feedback should be targeted toward junior or mid-career company grade officers and should relate to a significant occasion, such as advancement to a position with substantial oversight or influence. Our implementation and scaling recommendations consider civilian organization “best practices” and try to achieve meaningful results, enable growth, and avoid survey fatigue.Major, United States Marine CorpsMajor, United States Marine CorpsCaptain, United States Marine CorpsApproved for public release. Distribution is unlimited

    Entry in the ADHD drugs market: Welfare impact of generics and me-toos

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    Recent decades have seen a growth in treatments for attention deficit hyperactivity disorder (ADHD) including many branded and generic drugs. In the early 2000's, new drug entry dramatically altered market shares. We estimate a demand system for ADHD drugs and assess the welfare impact of new drugs. We find that entry induced large welfare gains by reducing prices of substitute drugs, and by providing alternative delivery mechanisms for existing molecules. Our results suggest that the success of follow-on patented drugs may come from unanticipated innovations like delivery mechanisms, a factor ignored by proposals to retard new follow-on drug approvals

    Bioluminescence intensity modeling and sampling strategy optimization

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    Author Posting. © American Meteorological Society 2005. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 22 (2005): 1267–1281, doi:10.1175/JTECH1760.1.The focus of this paper is on the development of methodology for short-term (1–3 days) oceanic bioluminescence (BL) predictions and the optimization of spatial and temporal bioluminescence sampling strategies. The approach is based on predictions of bioluminescence with an advection–diffusion–reaction (tracer) model with velocities and diffusivities from a circulation model. In previous research, it was shown that short-term changes in some of the salient features in coastal bioluminescence can be explained and predicted by using this approach. At the same time, it was demonstrated that optimization of bioluminescence sampling prior to the forecast is critical for successful short-term BL predictions with the tracer model. In the present paper, the adjoint to the tracer model is used to study the sensitivity of the modeled bioluminescence distributions to the sampling strategies for BL. The locations and times of bioluminescence sampling prior to the forecast are determined by using the adjoint-based sensitivity maps. The approach is tested with bioluminescence observations collected during August 2000 and 2003 in the Monterey Bay, California, area. During August 2000, BL surveys were collected during a strong wind relaxation event, while in August 2003, BL surveys were conducted during an extended (longer than a week) upwelling-favorable event. The numerical bioluminescence predictability experiments demonstrated a close agreement between observed and model-predicted short-term spatial and temporal changes of the coastal bioluminescence.This work has been supported by the Ocean Optics and Biology and Physical Oceanography Programs of the Office of Naval Research. Shulman’s support is through the NRL “Use of a Circulation Model to Enhance Predictability of Bioluminescence in the Coastal Ocean” project sponsored by the Office of Naval Research

    COVID-19 and non-COVID ARDS patients demonstrate a distinct response to low dose steroids- A retrospective observational study

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    Patients with COVID-19 ARDS have distinct physiological and immunological phenotypes compared to patients with non-COVID ARDS. Patients with COVID-19 ARDS (n = 32) had a significant improvement in PaO2: FiO2 ratio (p = 0.046) following low-dose steroid treatment, unlike patients with non-COVID ARDS (n = 16) (p = 0.529). Patients with COVID-19 ARDS had a greater fall in CRP compared to patients with non-COVID ARDS, albeit not statistically significant (p = 0.07). Our novel findings highlight differences in the underlying physiological and immunological phenotypes between COVID-19 and non-COVID ARDS, with implications for future ARDS studies
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