305 research outputs found

    Synthesis of 2-Alkynoates by Palladium(II)-Catalyzed Oxidative Carbonylation of Terminal Alkynes and Alcohols

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    A homogeneous Pd(II) catalyst, utilizing a simple and inexpensive amine ligand (TMEDA), allows 2‐alkynoates to be prepared in high yields by an oxidative carbonylation of terminal alkynes and alcohols. The catalyst system overcomes many of the limitations of previous palladium carbonylation catalysts. It has an increased substrate scope, avoids large excesses of alcohol substrate and uses a desirable solvent. The catalyst employs oxygen as the terminal oxidant and can be operated under safer gas mixtures

    Combined Oxypalladation/C-H Functionalization: Palladium(II)-Catalyzed Intramolecular Oxidative Oxyarylation of Hydroxyalkenes

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    An efficient protocol has been developed for the intramolecular oxidative oxyarylation using a Pd[superscript II]-catalyzed tandem oxypalladation/C-H functionalization strategy. This methodology allows rapid access to tetrahydro-2H-indeno-[2,1-b]furan frameworks from simple hydroxyalkenes. The reactivity of this process is orthogonal to that of Pd[superscript 0]-catalyzed transformations, enabling the divergent modification of a single molecule.National Institutes of Health (U.S.) (GM46059)National Institutes of Health (U.S.) (Grant 1S10RR13886-01)National Science Foundation (U.S.) (CHE-0946721

    Order and the Virtual: Toward a Deleuzian Cosmology

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    None provided, have taken the following from the "Introduction" Order is a more or less explicit topic for any thinker who undertakes to write about nature. Even those who assert that randomness or chaos is the most fundamental trait of nature are obliged to account for the apparent permanence, organisation and structure we observe around us. No less is true for Gilles Deleuze, who champions the power of chaos through his work. On one reading, Deleuze’s chief impulse is to wrench loose the lynchpins of order; to ‘affirm chaos’ and disarticulate the law of excluded middle; to refuse jurisdiction to laws of nature and render provisional its every constant; to banish identity and negation alike. If we are to be left with no fixed point, we might ask, what remains of order? This study is nevertheless an examination of that notion in Deleuze’s natural philosophy. For me the counter-reading is much more productive and insightful. Deleuze is rather a firm believer in order, even there where he affirms chaos. If we could furnish a ‘Deleuzian Question’ par excellence, it would be; ‘Given that there are no fixed points, how is order expressed in the world?’ This question is implicitly reprised across the entirety of his work and inflected at each stage by fresh vocabulary coined to treat it anew, as though for each new Deleuzian territory a new phrasebook is required

    Wi-Fi based people tracking in challenging environments

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    People tracking is a key building block in many applications such as abnormal activity detection, gesture recognition, and elderly persons monitoring. Video-based systems have many limitations making them ineffective in many situations. Wi-Fi provides an easily accessible source of opportunity for people tracking that does not have the limitations of video-based systems. The system will detect, localise, and track people, based on the available Wi-Fi signals that are reflected from their bodies. Wi-Fi based systems still need to address some challenges in order to be able to operate in challenging environments. Some of these challenges include the detection of the weak signal, the detection of abrupt people motion, and the presence of multipath propagation. In this thesis, these three main challenges will be addressed. Firstly, a weak signal detection method that uses the changes in the signals that are reflected from static objects, to improve the detection probability of weak signals that are reflected from the person’s body. Then, a deep learning based Wi-Fi localisation technique is proposed that significantly improves the runtime and the accuracy in comparison with existing techniques. After that, a quantum mechanics inspired tracking method is proposed to address the abrupt motion problem. The proposed method uses some interesting phenomena in the quantum world, where the person is allowed to exist at multiple positions simultaneously. The results show a significant improvement in reducing the tracking error and in reducing the tracking delay

    Rigorous dimension estimates for Cantor sets arising in Zaremba theory

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    We address the question of the accuracy of bounds used in the study of Zaremba’s conjecture. Specifically, we establish rigorous estimates on the Hausdorff dimension of certain Cantor sets which arise in the analysis of Zaremba’s conjecture in [5, 18, 19, 23]
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