3,646 research outputs found

    A new polymorph of N-(prop-2-yn­yl)tricyclo­[3.3.1.13,7]decane-1-carbox­amide

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    The alkynyl bond of the title compound, C14H19NO, has a length of 1.170 (5) Å. The amide function shows a trans conformation with respect to the carbonyl group characterized by the torsion angle O—C—N—H of −176 (2)°. There is an inter­molecular N—H⋯O hydrogen bond between the amide function and the carbonyl group. In addition, weak inter­molecular hydrogen bonds stabilize the crystal structure. A comparison with a polymorphic structure shows conformational differences with regard to the orientation of the carbonyl groups with respect to the adamantyl group [O—C—C—C = 96.2 (3)° in the title compound and 123.7 (2)° in the polymorph] and the orientations of the propargyl groups in relation to the carbonyl groups [O—C—C—C = −87.7 (3) and −58.7 (2)°, respectively]

    Chlorido[3,3′-dibutyl-5,5′-(pyridine-2,6-di­yl)dipyrazol-1-ido]gold(III)

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    The Au atom in the C2-symmetric pincer-type title complex, [AuCl(C19H23N5)], is in the +3 oxidation state. The ligand is composed of one pyridine unit and two n-butyl-substituted pyrazoles (pyrz). Both pyrazoles are deprotonated, thus forming a neutral compound. To the best of our knowledge, this is the first AuIII–bis­pyrazolate complex. According to the special geometry in the N,N′,N′′-tridentate ligand, containing two five-membered heterocycles, the complex deviates from an ideal square-planar coordination geometry; the Npyrz—Au—Npyrz angle is 160.8 (3)°, indicating a distortion of nearly 20°

    Slowing light through Zeeman Coherence Oscillations in a duplicated two-level system

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    We present the theory of a new method to slow a linearly polarized probe pulse as it propagates through a duplicated two-level system driven by an orthogonally polarized control field. The method makes use of Zeeman coherence oscillations (CZO) that arise in the atomic system because of the spatial and temporal modulation of the total polarization. This method exhibits properties similar to those that rely on the electromagnetically induced transparency (EIT) but without the existence of any trapping state. We demonstrated also the propagation of a dark polariton in the mediumComment: Rapid communication in PRA, 4 pages, 3 figures. Phys Rev A, rapid com. accepted (2008

    (Sp)-1-Diphenylphosphanyl-2-{(S)-[2-(diphenylphosphanyl)phenyl]hydroxymethyl}ferrocene

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    The absolute configuration of the title compound, [Fe(C5H5)(C36H29OP2)], is Sp at the ferrocene group and S at the asymmetric C atom. Both P atoms have a trigonal-pyramidal conformation. There is a short intramolecular C-H...P contact with an H...P distance of 2.56 Å. The hydroxy group is involved in an intramolecular O-H...[pi]phenyl interaction. The crystal packing shows five very weak intermolecular C-H...[pi] contacts, with H...Cg distances between 3.26 and 3.39 Å (Cg is the centroid of a phenyl or cyclopentadienyl ring). Key indicators: single-crystal X-ray study; T = 162 K; mean σ(C–C) = 0.004 Å; R factor = 0.038; wR factor = 0.083; data-to-parameter ratio = 22.3

    On the Efficiency tradeoffs in User-Centric Cloud RAN

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    Ambitious targets for aggregate throughput, energy efficiency and ubiquitous user experience are propelling the advent of ultra-dense networks. Intercell interference and high energy consumption in an ultra-dense network are the prime hindering factors in pursuit of these goals. To address the aforementioned challenges, in this paper, we propose a novel user-centric network orchestration solution for Cloud RAN based ultra-dense deployments. In this solution, a cluster (virtual disc) is created around users depending on their service priority. Within the cluster radius, only the best remote radio head (RRH) is activated to serve the user, thereby decreasing interference and saving energy. We use stochastic geometry based approach to quantify the area spectral efficiency (ASE) and RRH power consumption models to quantity energy(EE) efficiency of the proposed user-centric Cloud RAN (UCRAN). Through extensive analysis we observe that the cluster sizes that yield optimal ASE and EE are quite different. We propose a game theoretic self-organizing network (GT-SON) framework that can orchestrate the network between ASE and EE focused operational modes in real-time in response to changes in network conditions and the operator's revenue model, to achieve a Pareto optimal solution. A bargaining game is modeled to investigate the ASE-EE tradeoff through adjustment in the exponential efficiency weightage in the Nash bargaining solution (NBS). Results show that compared to current non-user centric network design, the proposed solution offers the flexibility to operate the network at multiple folds higher ASE or EE along with significant improvement in user experience

    Older adults and the unique role of the radiation therapist: Future directions for improving geriatric oncology training and education.

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    There is widespread recognition that the provision of high quality, appropriate and equitable care to older adults with cancer is a growing challenge in oncology practice. Radiation therapy (RT) is an effective and localised treatment that represents an attractive curative or palliative option for many older adults, and radiation therapists (RTT) play an important role in the delivery, support and quality of care for people during RT. The need to develop an evidence-based, global approach to improving all radiation oncology (RO) professionals' knowledge and clinical practice in geriatric oncology (GO) has been previously identified. This article specifically focusses on the status quo of GO clinical practice and education for RTT worldwide. We explore the unique clinical role that RTT play in the management of older adults with cancer and define multiple clinical care points in which RTT could potentially participate in geriatric screening, geriatric assessment and intervention to optimise the care of older adults, with a focus on dementia. Directions for future efforts to improve the knowledge and clinical skills of RTT in caring for older adults are discussed

    Homogeneous Gold Catalysis through Relativistic Effects: Addition of Water to Propyne

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    In the catalytic addition of water to propyne the Au(III) catalyst is not stable under non-relativistic conditions and dissociates into a Au(I) compound and Cl2. This implies that one link in the chain of events in the catalytic cycle is broken and relativity may well be seen as the reason why Au(III) compounds are effective catalysts.Comment: 12 pages, 3 figures, 1 tabl
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