986 resultados para Locally Nilpotent Derivations


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We study the dissipative dynamics of two independent arrays of many-body systems, locally driven by a common entangled field. We showthat in the steady state the entanglement of the driving field is reproduced in an arbitrarily large series of inter-array entangled pairs over all distances. Local nonclassical driving thus realizes a scale-free entanglement replication and long-distance entanglement distribution mechanism that has immediate bearing on the implementation of quantum communication networks. 

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A reduction in the time required to locate and restore faults on a utility's distribution network improves the customer minutes lost (CML) measurement and hence brings direct cost savings to the operating company. The traditional approach to fault location involves fault impedance determination from high volume waveform files dispatched across a communications channel to a central location for processing and analysis. This paper examines an alternative scheme where data processing is undertaken locally within a recording instrument thus reducing the volume of data to be transmitted. Processed event fault reports may be emailed to relevant operational staff for the timely repair and restoration of the line.

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Ancient stone monuments (ASMs), such as standing stones and rock art panels, are powerful and iconic expressions of Britain’s rich prehistoric past that have major economic and tourism value. However, ASMs are under pressure due to increasing anthropogenic exposure and changing climatic conditions, which accelerate their rates of disrepair. Although scientific data exists on the integrity of stone monuments, most applies to “built” systems; therefore, additional work specific to ASMs in the countryside is needed to develop better-informed safeguarding strategies. Here, we use Neolithic and Bronze Age rock art panels across Northern England as a case study for delineating ASM management actions required to enhance monument preservation. The state of the rock art is described first, including factors that led to current conditions. Rock art management approaches then are described within the context of future environments, which models suggest to be more dynamic and locally variable. Finally, a Condition Assessment and Risk Evaluation (CARE) scheme is proposed to help prioritise interventions; an example of which is provided based on stone deterioration at Petra in Jordon. We conclude that more focused scientific and behavioural data, specific to deterioration mechanisms, are required for an ASM CARE scheme to be successful.

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The Niger Coal Society (Societé Nigérienne de Charbon – SONICHAR) produces electricity for local consumption in Tefereyre, 75 km north-west from Agadez, Niger. The coal combustion residuals production is about 150,000 tons per year. In order to reduce this environmental burden and to valorize these by-products, a study focusing on their physical and chemical features as well as on the mechanical resistance of compressed brick has been undertaken. Physical characterization of coal slag, chemical and lixiviation tests have been carried out, assessing the material main parameters, verifying the presence of hazardous composites and elements and comparing the obtained results with the findings of an in-deep literary review. Cement powder has been chosen as stabilizing agent as a preliminary option. Four different dosages have been tested and bricks have been produced with a hand-operated press. Compressive strength has been tested at different days of curing. Results show remarkable uniaxial compressive strengths (UCS) for all the mixes after cure, ranging from 4MPa up to more than 20MPa for the highest stabilization ratio. UCS higher than 5MPa have been observed for 20% and 30% cement stabilization ratios after only 7 days of cure, reaching respectively about 11MPa and 13MPa after 45 days. In conclusion obtained bricks show good mechanical resistance and low weight. No health threat has been detected from the obtained sample. Study developments are oriented towards the feasibility of the utilization of low-cost, locally available stabilization means, notably clay and cohesive soils, and on thermal properties assessment.

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An academic–industrial partnership was formed with the aim of constructing a natural stone database for Northern Ireland that could be used by the public and practitioners to understand both the characteristics of the stone used in construction across Northern Ireland and how it has performed in use, and, through a linked database of historical quarries, explore the potential for obtaining locally sourced replacement stone. The aims were to improve the level of conservation specification by those with a duty of care for historical structures, and to enhance the quality of the conservation work undertaken by archi- tects and contractors through their improved knowledge of stone and stone decay processes.

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Healing algorithms play a crucial part in distributed peer-to-peer networks where failures occur continuously and frequently. Whereas there are approaches for robustness that rely largely on built-in redundancy, we adopt a responsive approach that is more akin to that of biological networks e.g. the brain. The general goal of self-healing distributed graphs is to maintain certain network properties while recovering from failure quickly and making bounded alterations locally. Several self-healing algorithms have been suggested in the recent literature [IPDPS'08, PODC'08, PODC'09, PODC'11]; they heal various network properties while fulfilling competing requirements such as having low degree increase while maintaining connectivity, expansion and low stretch of the network. In this work, we augment the previous algorithms by adding the notion of edge-preserving self-healing which requires the healing algorithm to not delete any edges originally present or adversarialy inserted. This reflects the cost of adding additional edges but more importantly it immediately follows that edge preservation helps maintain any subgraph induced property that is monotonic, in particular important properties such as graph and subgraph densities. Density is an important network property and in certain distributed networks, maintaining it preserves high connectivity among certain subgraphs and backbones. We introduce a general model of self-healing, and introduce xheal+, an edge-preserving version of xheal[PODC'11]. © 2012 IEEE.

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Let X be a connected, noetherian scheme and A{script} be a sheaf of Azumaya algebras on X, which is a locally free O{script}-module of rank a. We show that the kernel and cokernel of K(X) ? K(A{script}) are torsion groups with exponent a for some m and any i = 0, when X is regular or X is of dimension d with an ample sheaf (in this case m = d + 1). As a consequence, K(X, Z/m) ? K(A{script}, Z/m), for any m relatively prime to a. © 2013 Copyright Taylor and Francis Group, LLC.

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Ventilator-associated pneumonia (VAP) is characterized by neutrophils infiltrating the alveolar space. VAP is associated with high mortality, and accurate diagnosis remains difficult. We hypothesized that proteolytic enzymes from neutrophils would be significantly increased and locally produced inhibitors of human neutrophil elastase (HNE) would be decreased in BAL fluid (BALF) from patients with confirmed VAP. We postulated that in suspected VAP, neutrophil proteases in BALF may help identify "true" VAP.

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Objectives: This study measured and compared the pharmacokinetics of CMPD167, a small molecule antiretro- viral CCR5 inhibitor with potential as an HIV microbicide, following vaginal, rectal and oral administration in rhe- sus macaques.
Methods: A vaginal hydroxyethylcellulose (HEC) gel, a rectal HEC gel, a silicone elastomer matrix-type vaginal ring and an oral solution, each containing CMPD167, were prepared and administered to rhesus macaques pretreated with Depo-Provera. CMPD167 concentrations in vaginal fluid, vaginal tissue (ring only), rectal fluid and blood plasma were quantified by HPLC–mass spectrometry.
Results: CMPD167 concentrations measured in rectal fluid, vaginal fluid and blood plasma were highly depend- ent on both the route of administration and the formulation type. Although rectal and vaginal fluid concentra- tions were highest when CMPD167 was administered locally (via either gel or ring), lower concentrations of the drug were also measured in these compartments following administration at the remote mucosal site or orally. CMPD167 levels in the vaginal and rectal fluid following oral administration were relatively low compared with local administration.
Conclusions: The study provides clear evidence for vaginal – rectal and rectal – vaginal drug transfer pathways and suggests that oral pre-exposure prophylaxis with CMPD167 may be less efficacious at preventing sexual trans- mission of HIV-1 than topically applied products.

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This paper presents a preliminary study of developing a novel distributed adaptive real-time learning framework for wide area monitoring of power systems integrated with distributed generations using synchrophasor technology. The framework comprises distributed agents (synchrophasors) for autonomous local condition monitoring and fault detection, and a central unit for generating global view for situation awareness and decision making. Key technologies that can be integrated into this hierarchical distributed learning scheme are discussed to enable real-time information extraction and knowledge discovery for decision making, without explicitly accumulating and storing all raw data by the central unit. Based on this, the configuration of a wide area monitoring system of power systems using synchrophasor technology, and the functionalities for locally installed open-phasor-measurement-units (OpenPMUs) and a central unit are presented. Initial results on anti-islanding protection using the proposed approach are given to illustrate the effectiveness.

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A new strategy for remote reconfiguration of an antenna array far field radiation pattern is described. The scheme uses a pilot tone co-transmitted with a carrier signal from a location distant from that of a receive antenna array whose far field pattern is to be reconfigured. By mixing the co-transmitted signals locally at each antenna element in the array an IF signal is formed which defines an equivalent array spacing that can be made variable by tuning the frequency of the pilot tone with respect to the RF carrier. This makes the antenna array factor hence far field spatial characteristic reconfigurable on receive. For a 10 x 1 microstrip patch element array we show that the receive pattern can be made to vary from 35 to 10 degrees half power beam width as the difference frequency between the pilot and the carrier at 2.45 GHz varies between 10 MHz and 500 MHz carrier.