914 resultados para Third-order correlation


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A cyclic marl-limestone succession of Middle-Late Campanian age has been investigated with respect to a Milankovitch-controlled origin of geochemical data. In general, the major element geochemistry of the marl-limestone rhythmites can be explained by a simple two-component mixing model with the end-members calcium carbonate and 'average shale'-like material. Carbonate content varies from 55 to 90%. Non-carbonate components are clay minerals (illite, smectite) and biogenic silica from sponge spicules, as well as authigenically formed zeolites (strontian heulandite) and quartz. The redox potential suggests oxidizing conditions throughout the section. Trace element and stable isotopic data as well as SEM investigations show that the carbonate mud is mostly composed of low-magnesium calcitic tests of planktic coccolithophorids and calcareous dinoflagellate cysts (calcispheres). Diagenetic overprint results in a decrease of 2% d18O and an increase in Mn of up to 250 ppm. However, the sediment seems to preserve most of its high Sr content compared to the primary low-magnesium calcite of co-occurring belemnite rostra. The periodicity of geochemical cycles is dominated by 413 ka and weak signals between 51 and 22.5 ka, attributable to orbital forcing. Accumulation rates within these cycles vary between 40 and 50 m/Ma. The resulting cyclic sedimentary sequence is the product of (a) changes in primary production of low-magnesium calcitic biogenic material in surface waters within the long eccentricity and the precession, demonstrated by the CaCO3 content and the Mg/Al, Mn/Al and Sr/Al ratios, and (b) fluctuations in climate and continental weathering, which changed the quality of supplied clay minerals (the illite/smectite ratio), demonstrated by the K/Al ratio. High carbonate productivity correlates with smectite-favouring weathering (semi-arid conditions, conspicuously dry and moist seasonal changes in warmer climates). Ti as the proxy indicator for the detrital terrigenous influx, as well as Rb, Si, Zr and Na, shows only low frequency signals, indicating nearly constant rates of supply throughout the more or less pure pelagic carbonate deposition of the long-lasting third-order Middle-Upper Campanian sedimentary cycle.

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This letter proposes a high-linearity reconfigurable lower ultra-wideband (3.1–5.25 GHz) filter with independently controlled dual bandnotch at WiMAX 3.5 GHz band and satellite communication systems 4.2 GHz band. Reconfigurability has been achieved by the implementation of Graphene based switches (simulation only) and PIN diodes (measurements). The simulation and measurement results in OFF state show an entire bandpass response from 3.1 GHz to 5.25 GHz and with a very low insertion loss. In ON state, the results show that sharp rejections at 3.5 GHz and 4.2 GHz are achieved, with a low passband insertion loss. The two bandnotch operate independently of each other; thus allowing to control the behaviour of the required bandnotch. The third order intermodulation products were also measured in OFF and ON states and the linearity results have been presented. The filter is able to achieve a high performance with good linearity and no significant loss.

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Background:  Most qualitative studies exploring the impactof prostate cancer on men and their partners consider the dominant ethnicgroups in the USA, UK, Scandinavia and Australia, with generally concordantfindings.  Other ethnic groups are likelyto have different experiences.

Aims: To explorethe impact of prostate cancer and its treatment on men and their partners fromthe less studied ethnic groups.

Methods: Using meta-ethnographyand textual narrative we synthesised peer reviewed qualitative interview-based studiesdated 2000-2015 focused on less well reported ethnic groups, as a sub-synthesisof a comprehensive metasynthesis on the impact of prostate cancer.

Results: Twenty-twopapers (15 studies) covering 11 ethnic groups were analysed.  Nine studies considered black and minorityethnic groups in the UK and USA, with the remainder in Brazil, the PacificIslands, Israel, Turkey and Japan. We collected first and second order themesfrom the studies to develop conceptual third order themes with the following specificto the US and UK minority groups andPacific Islanders: A spiritual continuum: from the will of God to God ashelpmate; One more obstacle in the lifelong fight against adversity; Developingsensitive talk with a purpose (on disclosingthe cancer to informal networks in culturally appropriate ways). Themes from theother studies were similar to those in the overall metasynthesis.

Conclusions: Healthcare for prostate cancer should takeaccount of contextually and culturally specific coping mechanisms andpsychosocial factors in minority ethnic groups. More studies are needed indiverse ethnic groups.

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This paper presents an extension to the energy vector, well known in the Ambisonics literature, to improve its predictions of localisation at off-centre listening positions. In determining the source direction, a perceptual weight is assigned to each loudspeaker gain, taking into account the relative arrival times, levels, and directions of the loudspeaker signals. The proposed model is evaluated alongside the original energy vector and two binaural models through comparison with the results of recent perceptual studies. The extended version was found to provide results that were at least 50% more accurate than the second best predictor for two experiments involving off-centre listeners with first- and third-order Ambisonics systems.

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The transistor laser is a unique three-port device that operates simultaneously as a transistor and a laser. With quantum wells incorporated in the base regions of heterojunction bipolar transistors, the transistor laser possesses advantageous characteristics of fast base spontaneous carrier lifetime, high differential optical gain, and electrical-optical characteristics for direct “read-out” of its optical properties. These devices have demonstrated many useful features such as high-speed optical transmission without the limitations of resonance, non-linear mixing, frequency multiplication, negative resistance, and photon-assisted switching. To date, all of these devices operate as multi-mode lasers without any type of wavelength selection or stabilizing mechanisms. Stable single-mode distributed feedback diode laser sources are important in many applications including spectroscopy, as pump sources for amplifiers and solid-state lasers, for use in coherent communication systems, and now as TLs potentially for integrated optoelectronics. The subject of this work is to expand the future applications of the transistor laser by demonstrating the theoretical background, process development and device design necessary to achieve singlelongitudinal- mode operation in a three-port transistor laser. A third-order distributed feedback surface grating is fabricated in the top emitter AlGaAs confining layers using soft photocurable nanoimprint lithography. The device produces continuous wave laser operation with a peak wavelength of 959.75 nm and threshold current of 13 mA operating at -70 °C. For devices with cleaved ends a side-mode suppression ratio greater than 25 dB has been achieved.

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This thesis focuses on digital equalization of nonlinear fiber impairments for coherent optical transmission systems. Building from well-known physical models of signal propagation in single-mode optical fibers, novel nonlinear equalization techniques are proposed, numerically assessed and experimentally demonstrated. The structure of the proposed algorithms is strongly driven by the optimization of the performance versus complexity tradeoff, envisioning the near-future practical application in commercial real-time transceivers. The work is initially focused on the mitigation of intra-channel nonlinear impairments relying on the concept of digital backpropagation (DBP) associated with Volterra-based filtering. After a comprehensive analysis of the third-order Volterra kernel, a set of critical simplifications are identified, culminating in the development of reduced complexity nonlinear equalization algorithms formulated both in time and frequency domains. The implementation complexity of the proposed techniques is analytically described in terms of computational effort and processing latency, by determining the number of real multiplications per processed sample and the number of serial multiplications, respectively. The equalization performance is numerically and experimentally assessed through bit error rate (BER) measurements. Finally, the problem of inter-channel nonlinear compensation is addressed within the context of 400 Gb/s (400G) superchannels for long-haul and ultra-long-haul transmission. Different superchannel configurations and nonlinear equalization strategies are experimentally assessed, demonstrating that inter-subcarrier nonlinear equalization can provide an enhanced signal reach while requiring only marginal added complexity.

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We consider a two-dimensional Fermi-Pasta-Ulam (FPU) lattice with hexagonal symmetry. Using asymptotic methods based on small amplitude ansatz, at third order we obtain a eduction to a cubic nonlinear Schr{\"o}dinger equation (NLS) for the breather envelope. However, this does not support stable soliton solutions, so we pursue a higher-order analysis yielding a generalised NLS, which includes known stabilising terms. We present numerical results which suggest that long-lived stationary and moving breathers are supported by the lattice. We find breather solutions which move in an arbitrary direction, an ellipticity criterion for the wavenumbers of the carrier wave, symptotic estimates for the breather energy, and a minimum threshold energy below which breathers cannot be found. This energy threshold is maximised for stationary breathers, and becomes vanishingly small near the boundary of the elliptic domain where breathers attain a maximum speed. Several of the results obtained are similar to those obtained for the square FPU lattice (Butt \& Wattis, {\em J Phys A}, {\bf 39}, 4955, (2006)), though we find that the square and hexagonal lattices exhibit different properties in regard to the generation of harmonics, and the isotropy of the generalised NLS equation.

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Using asymptotic methods, we investigate whether discrete breathers are supported by a two-dimensional Fermi-Pasta-Ulam lattice. A scalar (one-component) two-dimensional Fermi-Pasta-Ulam lattice is shown to model the charge stored within an electrical transmission lattice. A third-order multiple-scale analysis in the semi-discrete limit fails, since at this order, the lattice equations reduce to the (2+1)-dimensional cubic nonlinear Schrödinger (NLS) equation which does not support stable soliton solutions for the breather envelope. We therefore extend the analysis to higher order and find a generalised $(2+1)$-dimensional NLS equation which incorporates higher order dispersive and nonlinear terms as perturbations. We find an ellipticity criterion for the wave numbers of the carrier wave. Numerical simulations suggest that both stationary and moving breathers are supported by the system. Calculations of the energy show the expected threshold behaviour whereby the energy of breathers does {\em not} go to zero with the amplitude; we find that the energy threshold is maximised by stationary breathers, and becomes arbitrarily small as the boundary of the domain of ellipticity is approached.

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Background: The goal of stroke rehabilitation has shifted from mere survival of a victim to how well a survivor can be effectively reintegrated back into the community. Objectives: The present study determined the level of satisfaction with community reintegration (CR) and related factors among Nigerian community-dwelling stroke survivors (CDSS). Methods: This was a cross-sectional survey of 71 volunteering CDSS (35 males, 36 females) from selected South-Eastern Nigerian communities. Reintegration to Normal Living Index was used to assess participants’ CR. Data was analysed using Spearman rank-order correlation, Kruskal-Wallis and Mann-Whitney U tests at p≤0.05. Results: Participants generally had deficits in CR which was either mild/moderate (52.1%) or severe (47.9%). Scores in the CR domains of distance mobility, performance of daily activities, recreational activities and family roles were particularly low (median scores ≤ 4). CR was significantly correlated with and influenced by age (r=-0.35; p=0.00) and presence/absence of diabetes mellitus (u=3.56.50; p=0.01), pre- (k=6.13; p=0.05) and post-stroke employment (k=18.26; p=0.00) status, type of assistive mobility device being used (AMD) (k=25.39; p=0.00) and support from the community (k=7.15; p=0.03) respectively. Conclusion: CR was generally poor for this CDSS sample. Survivors who are older, having diabetes as co-morbidity, using AMD (particularly wheel-chair) and without employment pre- and/or post-stroke may require keener attention. Rehabilitation focus may be targeted at enhancing mobility functions, vocational and social skills.

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The energy equation for turbulent flow of fiber suspensions was derived in terms of second order correlation tensors. Fiber motion of turbulent energy including the correlation between pressure fluctuations and velocity fluctuations was discussed at two points of flow field, at which the correlation tensors were the functions of space coordinates, distance between two points, and time.

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Accurate assessment of physical activity energy expenditure (PAEE) among adolescents is important for surveillance, evaluating interventions, and understanding the relation between energy balance and normal physiological and behavioral growth and development. The purpose of this study was to examine the validity of the Short Questionnaire to Assess Health-Enhancing Physical Activity (SQUASH)13 for measuring PAEE among adolescents. Methods: The participants were seventeen adolescents (9 females; Mean age = 17.53; SD = 0.62). Energy expenditure was measured during a 9-day period with doubly labeled water (DLW). The SQUASH was self-administered on the morning of the 10th day and assessed commuting activities, leisure time activities, household activities, and activities at work and school over the previous 9 days. Results: A Bland-Altman plot indicated that the SQUASH underestimated PAEE compared with DLW by a mean difference of 126 kcal·d-1 (95% limits of agreement:-1,207 to 1,459 kcal·d-1), representative of a 10% underestimation. The Spearman rank order correlation coefficient showed there was a significant association between the SQUASH and DLW (r =.50, P =.04), for estimating PAEE. Conclusion: When using a sample of highly active adolescents, the SQUASH is a valid self-report tool for measuring PAEE at the group and individual rank order level.

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A temática proposta como objeto de estudo na presente tese, é o resultado de uma investigação dedicada ao fenómeno de utilização da imaginária processional nos cortejos de penitência de pendor franciscano, nos séculos XVII a XX na ilha de S. Miguel, Açores. Este tipo de manifestações religiosas, particularmente característico no espaço Iberoamericano, evidencia-se pela originalidade cenográfica, na qual são utilizados vestuário e adereços cénicos como complementos dos respetivos conjuntos escultóricos, as denominadas imagens de vestir. No arquipélago dos Açores, a Venerável Ordem Terceira da Penitência teve um papel de grande importância na organização destes eventos processionais, sendo que as ilhas de S. Miguel e da Terceira representam atualmente um dos últimos redutos na organização de procissões penitenciais, com recurso à utilização de imagens de vestir. No caso especifíco de S. Miguel, este tipo de imaginária pode ser ainda observada nos acervos de algumas das antigas igrejas conventuais da Ordem dos Frades Menores existentes nesta ilha, bem como na única procissão oriunda do espírito penitencial da Ordem Terceira, que se realiza anualmente na cidade da Ribeira Grande. O estudo agora apresentado pretende compreender as diversas componentes da utilização deste tipo de imaginária, bem como o registo do legado patrimonial que os seculares franciscanos perpetuaram até à atualidade, materializado num processo de patrimonialização das suas imagens de vestir, expresso na dicotomia entre os objetos, enquanto matéria, e as suas realidades biográficas, ligadas às comunidades de Terceiros que estiveram por detrás do uso destas imagens processionais; ABSTRACT: Religious sculptures for dressing of the Third Procession: history, concepts, typologies and traditions - A Franciscan heritage legacy in the island of S. Miguel, Azores, between the 17th and 19th centuries. The theme proposed as object of study in this thesis is the result of a research dedicated to the custom of adorning religious sculptures and displaying them in Franciscan penitential processions between the seventeenth and twentieth centuries, in the island of S. Miguel, Azores. This type of religious expression, particularly characteristic in the Ibero-American space, featuring up by scenic originality, in which clothing and scenic props are used to complement the respective sculptural groups, called religious sculptures for dressing. In the Azores, the Venerable Third Order of Penance had a major role in organizing these processional events, and the islands of S. Miguel and Terceira currently represents one of the last holdouts in organizing penitential processions, with the use of religious sculptures for dressing. In the case of S. Miguel, this type of imaginary can still be seen in the collections of some of the ancient Order of the convent churches of the Friars Minor existing on this island, and the only procession coming from the penitential spirit of the Third Order, which is held annually in the city of Ribeira Grande. The study now being presented aims to understand the various components of the use of such imaginary, and the recording of heritage legacy that the Franciscan secular perpetuated to the present day, materialized in a patrimonialization process of their dress images, expressed in the dichotomy between objects, as matter, and their biographical realities, linked to third-party communities that were behind the use of these processional images.

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Glenwood Homes Pty Ltd v Everhard [2008] QSC 192 involved the not uncommon situation where one costs order is made against several parties represented by a single firm of solicitors. Dutney J considered the implications when only some of the parties liable for the payment of the costs file a notice of objection to the costs statement served in respect of those costs.

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Materials with widely varying molecular topologies and exhibiting liquid crystalline properties have attracted considerable attention in recent years. C-13 NMR spectroscopy is a convenient method for studying such novel systems. In this approach the assignment of the spectrum is the first step which is a non-trivial problem. Towards this end, we propose here a method that enables the carbon skeleton of the different sub-units of the molecule to be traced unambiguously. The proposed method uses a heteronuclear correlation experiment to detect pairs of nearby carbons with attached protons in the liquid crystalline core through correlation of the carbon chemical shifts to the double-quantum coherences of protons generated through the dipolar coupling between them. Supplemented by experiments that identify non-protonated carbons, the method leads to a complete assignment of the spectrum. We initially apply this method for assigning the C-13 spectrum of the liquid crystal 4-n-pentyl-4'-cyanobiphenyl oriented in the magnetic field. We then utilize the method to assign the aromatic carbon signals of a thiophene based liquid crystal thereby enabling the local order-parameters of the molecule to be estimated and the mutual orientation of the different sub-units to be obtained.

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Based on the phase-conjugation polarization interference between two two-photon processes, we theoretically investigated the attosecond scale asymmetry sum-frequency polarization beat in four-level system (FASPB). The field correlation has weak influence on the FASPB signal when the laser has narrow bandwidth. Conversely, when the laser has broadband linewidth, the FASPB signal shows resonance-nonresonance cross correlation. The two-photon signal exhibits hybrid radiation-matter detuning terahertz; damping oscillation, i.e., when the laser frequency is off resonance from the two-photon transition, the signal exhibits damping oscillation and the profile of the two-photon self-correlation signal also exhibits zero time-delay asymmetry of the maxima. We have also investigated the asymmetry of attosecond polarization beat caused by the shift of the two-photon self-correlation zero time-delay phenomenon, in which the maxima of the two two-photon signals are shifted from zero time-delay point to opposite directions. As an attosecond ultrafast modulation process, FASPB can be intrinsically extended to any level-summation systems of two dipolar forbidden excited states.