580 research outputs found

    Modular quantum signal processing in many variables

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    Despite significant advances in quantum algorithms, quantum programs in practice are often expressed at the circuit level, forgoing helpful structural abstractions common to their classical counterparts. Consequently, as many quantum algorithms have been unified with the advent of quantum signal processing (QSP) and quantum singular value transformation (QSVT), an opportunity has appeared to cast these algorithms as modules that can be combined to constitute complex programs. Complicating this, however, is that while QSP/QSVT are often described by the polynomial transforms they apply to the singular values of large linear operators, and the algebraic manipulation of polynomials is simple, the QSP/QSVT protocols realizing analogous manipulations of their embedded polynomials are non-obvious. Here we provide a theory of modular multi-input-output QSP-based superoperators, the basic unit of which we call a gadget, and show they can be snapped together with LEGO-like ease at the level of the functions they apply. To demonstrate this ease, we also provide a Python package for assembling gadgets and compiling them to circuits. Viewed alternately, gadgets both enable the efficient block encoding of large families of useful multivariable functions, and substantiate a functional-programming approach to quantum algorithm design in recasting QSP and QSVT as monadic types.Comment: 15 pages + 9 figures + 4 tables + 45 pages supplement. For codebase, see https://github.com/ichuang/pyqsp/tree/bet

    In-plane behaviour of masonry walls: Numerical analysis and design formulations

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    This paper presents the results of several numerical analyses aimed at investigating the in-plane resistance of masonry walls by means of two modelling approaches: a finite element model (FEM) and a discrete macro-element model (DMEM). Non-linear analyses are developed, in both cases, by changing the mechanical properties of masonry (compressive and tensile strengths, fracture energy in compression and tension, shear strength) and the value of the vertical compression stress applied on the walls. The reliability of both numerical models is firstly checked by means of comparisons with experimental tests available in the literature. The analyses show that the numerical results provided by the two modelling approaches are in good agreement, in terms of both failure loads and modes, while some differences are observed in their load-displacement curves, espe-cially in the non-linear field. Finally, the numerical in-plane resistances are compared with the theoretical formulations provided by the Italian building code for both flexural and shear failure modes and an amendment for the shape factor ‘b’ introduced in the code formulation for squat walls is proposed

    Literature review of the in-plane behavior of masonry walls: Theoretical vs. experimental results

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    In-plane strength of masonry walls is affected by the resistant mechanisms activated in the walls, i.e., related to flexural or shear behavior. The latter one can occur in the walls according to different failure modes depending on both mortar and unit strengths and on the type of assembling, i.e., ‘regular’ or ‘irregular’ texture. In this paper, a critical review of the existing design formulations for the in-plane strength of masonry walls is firstly presented, with important information on the achievable failure modes depending on the geometrical and mechanical features of the masonry fabric. Then, experimental tests are collected from the literature and a comparison between theoretical and experimental results is carried out. The presented analyses are aimed to highlight the differences between the existing formulations and to identify the most suitable ones

    Electrochemical C(sp3)-H functionalization of ethers via hydrogen-atom transfer by means of cathodic reduction

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    : The chemo- and stereoselective electrochemical allylation/alkylation of ethers is presented via a C(sp3)-H activation event. The electrosynthetic protocol enables the realization of a large library of functionalized ethers (35 examples) in high yields (up to 84%) via cathodic activation of a new type of redox-active carbonate (RAC), capable of triggering HAT (Hydrogen-Atom-Transfer) events through the generation of electrophilic oxy radicals. The process displayed high functional group tolerance and mild reaction conditions. A mechanistic elucidation via voltammetric analysis completes the study

    Real-world use of oral versus subcutaneous semaglutide in a cohort of type 2 diabetic patients: which option to which patient?

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    Purpose To evaluate the variables influencing the therapeutic choice toward oral versus subcutaneous semaglutide in a cohort of diabetic subjects.Methods We retrospectively collected data of 292 patients followed at the Diabetes Unit of the University Hospital of Siena and the Hospital of Grosseto, who were prescribed oral (n = 115) or subcutaneous (n = 177) semaglutide between October 2021 and October 2022.Results Oral semaglutide was preferentially prescribed in older subjects with longer disease duration in replacement of other antidiabetic drugs, while subcutaneous semaglutide was preferentially prescribed in add-on to metformin in subjects with higher body weight and BMI. After 6 months, both formulations significantly improved glycemic control and body weight, however injectable semaglutide showed a greater efficacy on A1c levels, weight loss, BMI and waist circumference reduction. No differences were found in terms of adverse events.Conclusion In our experience, injectable semaglutide is preferred in patients with excess weight and shorter disease duration, while the oral formulation was used later and especially after therapeutic failure of previous therapies. Follow-up data indicate similar tolerability and efficacy of both formulations, despite subcutaneous semaglutide demonstrated greater efficacy

    Aluminum(III) Salen Complexes as Active Photoredox Catalysts

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    Metallosalen are privileged complexes that have found important applications in catalysis. In addition, their luminescent properties have also been studied and used for sensing and biological applications. Salen metal complexes can be efficient photosensitizers, but they can also participate to electron transfer processes. Indeed, we have found that commercially available [Al(Salen)Cl] is an efficient photoredox catalyst for the synergistic stereoselective reaction of alkyl aldehydes with different bromo ketones and malonates to give the corresponding enantioenriched α-alkylated derivatives. The reaction was performed in the presence of a MacMillan catalyst. [Al(Salen)Cl] is able to replace ruthenium complexes, showing that also aluminum complexes can be used in promoting photoredox catalytic reactions

    Agro-climate tools for a new climate-smart agriculture

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    The way we produce food must adapt to a variable and changing climate. And key to achieving this is to improve the link between climate information and agricultural practices, especially those of smallholder farmers in developing countries. ‘Agro-climate tools’ do just that and some are introduced here

    Photoelectrochemical Valorization of Biomass Derivatives with Hematite Photoanodes Modified by Cocatalysts

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    The solar-driven oxidation of biomass to valuable chemicals is rising as a promising anodic reaction in photoelectrochemical cells, replacing the sluggish oxygen evolution reaction and improving the added value of the energy conversion process. Herein, the photooxidation of 5-hydroxymethylfurfural into furan dicarboxylic acid (FDCA) is performed in basic aqueous environment (borate buffer, pH 9.2), with the addition of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as redox mediator. Because of its good stability, cost-effectiveness, and nontoxicity, titanium-modified hematite (Ti:Fe2O3) photoanodes are investigated to this aim, and their performance is tuned by engineering the semiconductor surface with a thin layer of Co-based cocatalysts, i.e., cobalt iron oxide (CoFeO x ) and cobalt phosphate (CoPi). Interestingly, the electrode modified with CoPi shows improved efficiency and selectivity toward the final product FDCA The source of this enhancement is correlated to the effect of the cocatalyst on the charge carrier dynamics, which is investigated by electrochemical impedance spectroscopy and intensity-modulated photocurrent spectroscopy analysis. In addition, the results of the latter are interpreted through a novel approach called Lasso distribution of relaxation time, revealing that CoPi cocatalyst is effective in the suppression of the recombination processes and in the enhancement of direct hole transfer to TEMPO
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