14,795 research outputs found

    Atomic clouds as distributed sources for the plasma torus

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    Implications of recent developments for the neutral particle environment of Jupiter are considered. The first detection is reported of very hot S+ ions with gyrospeeds comparable to the corotations speed, a phenomenon which results from a neutral sulfur cloud. Evidence supports the hypothesis that extensive neutral clouds of oxygen and sulfur exist and are important sources of ions and energy for the Io torus

    Phase Diagram of the 1D Kondo Lattice Model

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    We determine the boundary of the fully polarized ferromagnetic ground state in the one dimensional Kondo lattice model at partial conduction electron band filling by using a newly developed infinite size DMRG method which conserves the total spin quantum number. The obtained paramagnetic to ferromagnetic phase boundary is below J3.5J \approx 3.5 for the whole range of band filling. By this we solve the controversy in the phase diagram over the extent of the ferromagnetic region close to half filling.Comment: 6 pages, 4 EPS figures. Presented at MOS9

    Review of presentations at the 6th European Lupus Meeting 3-5 March 2005.

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    The 6th European Lupus Meeting was held at the Royal College of Physicians of London and was attended by 450 delegates. The conference brought together leading speakers from Europe and North America who reviewed current knowledge and exciting new developments in both clinical and basic science aspects of systemic lupus erythematosus. This review summarizes the major points covered in each session

    Comparative performance analysis of Vacuum Insulation Panels in thermal window shutters

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    Windows are a major area of heat loss in buildings and can lose up to 10 times more energy than other building elements. In a typical house, around 10% of heat is lost through the windows. Thermal shutters could considerably reduce heat losses through windows and improve the energy performance of buildings. Insulation plays a major role in overall performance of thermal shutters. Advance insulation material such as Vacuum Insulation Panel (VIP) can help in improving the performance of thermal window shutters. VIP with a thermal conductivity of 0.005-0.008 W/mK is a high thermal resistance and energy efficient alternative to conventional thermal insulation materials. In this paper, effect of VIP and conventional insulation has been investigated and compared for enhancing the thermal performance of window shutters using computer simulations. Results indicate significant reduction in heat loss through windows when VIP insulation was employed in internal thermal window shutters. Thermal bridging was found to be the significant factor that deteriorated the performance of the shutter. Reducing heat loss through the frame and surrounding walls could improve the VIP insulated shutter thermal performance by approximately nine times

    Rainfall Incidences and Groundwater Characteristics in the Sedimentary Basin Of Sokoto Metropolis, Nigeria

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    Groundwater fluctuation is an important phenomenon in water supply within semi-arid regions. Sokoto state has a dry season of 8 months and rainy season of 4 months; this has a profound impact on groundwater level. This study examines groundwater fluctuation within Sokoto metropolis. Groundwater levels in selected shallow wells were monitored after 3 incidences of rainfall in 20 shallow water wells between May and June, 2011. Measuring tape and Global Positioning System (GPS) were used as instruments of data collection. The water levels and the GPS values served as input into Surfer 10 Digital Elevation Mapper, using 3D (Dimension) digitizing and one grid vector mapping techniques. Also, digitized map of Sokoto metropolis was imported into Surfer 10 digital elevation Mapper environment to enable the positioning of the sampled sites of water levels for both dry and rainy events. One grid vector was used to classify Sokoto metropolis into areas of high, moderate and low water levels. One way ANOVA statistical technique was used to test differences in rainfall and water level fluctuations in shallow wells of Sokoto metropolis. The results showed that there were no significant variations between levels of groundwater with rainfall events. It also showed that groundwater flow in Sokoto metropolis is in 4 different directions. In addition, Sokoto metropolis was classified into 6 regional groundwater regions. The paper suggests a need for further study

    Juncture prosody across languages: Similar production but dissimilar perception

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    How do speakers of languages with different intonation systems produce and perceive prosodic junctures in sentences with identical structural ambiguity? Native speakers of English and of Mandarin produced potentially ambiguous sentences with a prosodic juncture either earlier in the utterance (e.g., “He gave her # dog biscuits,” “他给她#狗饼干 ”), or later (e.g., “He gave her dog # biscuits,” “他给她狗 #饼干 ”). These productiondata showed that prosodic disambiguation is realised very similarly in the two languages, despite some differences in the degree to which individual juncture cues (e.g., pausing) were favoured. In perception experiments with a new disambiguation task, requiring speeded responses to select the correct meaning for structurally ambiguous sentences, language differences in disambiguation response time appeared: Mandarin speakers correctly disambiguated sentences with earlier juncture faster than those with later juncture, while English speakers showed the reverse. Mandarin-speakers with L2 English did not show their native-language response time pattern when they heard the English ambiguous sentences. Thus even with identical structural ambiguity and identically cued production, prosodic juncture perception across languages can differ

    Q-operator and fusion relations for U<sub>q</sub>(C<sup>(2)</sup>(2))

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    ‘I see the future’: Associations between innovation and resources in the case of an exporting Western Australian regional family firm

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    Purpose – The purpose of this study is to investigate the associations between the resources of a Western Australian regional family firm exporting to Asia and innovation through the lens of the theory of innovation and the resource based view (RBV) of the firm. Design/methodology/approach – In-depth, un-structured telephone and face-to-face interviews were conducted with five members of the firm, including the co-owner. A visit to the business facilities complemented the data collection process. Findings – The importance of tangible and intangible resources, such as forward thinking or investments in technologies, human capital and research is clearly illustrated; these resources positively influence innovative practices. Associations between the findings and the theoretical frameworks were identified. For instance, the imperfectly imitable and non-substitutable attributes comply with the RBV of the firm, and the hypothesised four dimensions of innovation. Importantly, the significance of strategic partnering emerges as an extension of these attributes. Originality/value – This study addresses some knowledge gaps, first, contributing to the body of research on family firms’ adoption of innovation. In addition, the study contributes to the literature on regional Western Australian family firms operating internationally. This state makes a significant contribution to Australia’s economy, and its close geographic proximity to various important consumer markets highlights future opportunities for family firms in international trade. Despite such potential, research on global family firms operating in this state has been almost non-existent

    Non-thermal Origin of the EUV and Soft X-rays from the Coma Cluster - Cosmic Rays in Equipartition with the Thermal Medium

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    The role of cosmic rays (CR) in the formation and evolution of clusters of galaxies has been much debated. It may well be related to other fundamental questions, such as the mechanism which heats and virializes the intracluster medium (ICM), and the frequency at which the ICM is shocked. There is now compelling evidence both from the cluster soft excess (CSE) and the `hard-tail' emissions at energies above 10 keV, that many clusters are luminous sources of inverse-Compton (IC) emission. This is the first direct measurement of cluster CR: the technique is free from our uncertainties in the ICM magnetic field, and is not limited to the small subset of clusters which exhibit radio halos. The CSE emitting electrons fall within a crucial decade of energy where they have the least spectral evolution, and where most of the CR pressure resides. However their survival times do not date them back to the relic CR population. By using the CSE data of the Coma cluster, we demonstrate that the CR are energetically as important as the thermal ICM: the two components are in pressure equiparition. Thus, contrary to previous expectations, CR are a dominant component of the ICM, and their origin and effects should be explored. The best-fit CR spectral index is in agreement with the Galactic value.Comment: ApJ accepted; 10 pages LaTeX; 2 figures and 1 table in PostScrip

    A comparison of Monte Carlo-based Bayesian parameter estimation methods for stochastic models of genetic networks

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    We compare three state-of-the-art Bayesian inference methods for the estimation of the unknown parameters in a stochastic model of a genetic network. In particular, we introduce a stochastic version of the paradigmatic synthetic multicellular clock model proposed by Ullner et al., 2007. By introducing dynamical noise in the model and assuming that the partial observations of the system are contaminated by additive noise, we enable a principled mechanism to represent experimental uncertainties in the synthesis of the multicellular system and pave the way for the design of probabilistic methods for the estimation of any unknowns in the model. Within this setup, we tackle the Bayesian estimation of a subset of the model parameters. Specifically, we compare three Monte Carlo based numerical methods for the approximation of the posterior probability density function of the unknown parameters given a set of partial and noisy observations of the system. The schemes we assess are the particle Metropolis-Hastings (PMH) algorithm, the nonlinear population Monte Carlo (NPMC) method and the approximate Bayesian computation sequential Monte Carlo (ABC-SMC) scheme. We present an extensive numerical simulation study, which shows that while the three techniques can effectively solve the problem there are significant differences both in estimation accuracy and computational efficiency
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