693 research outputs found

    Application of mid-infrared spectroscopy for rapid characterization of key soil properties for engineering land use

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    AbstractMethods for rapid and accurate soil tests are needed for the index properties of material attributes commonly applied in civil engineering. We tested the application of mid-infrared (MIR) spectroscopy for the rapid characterization of selected key stability-related soil properties. Two sample sets, representing different soils from across Lake Victoria basin in Kenya, were used for the study: A model calibration set (n=135) was obtained following a conditioned Latin hypercube sampling, and a validation set (n=120) was obtained from independent sites using a spatially stratified random sampling strategy. Air-dried ground (<0.5mm) soil was scanned using a high-throughput screening accessory for diffuse reflectance attached to a Fourier transform infrared spectrometer. The soil properties were calibrated to smoothed first derivative MIR spectra using partial least-square regression (PLS), and screening tests were developed for various limitation classes applicable in civil works using the soft independent modeling of class analogy (SIMCA). The hold-out full cross-validation coefficient of determination (r2)≥0.8 was obtained for the liquid limit (LL), linear shrinkage (LS), coefficient of linear extensibility (COLE), air-dried moisture content, (W) and cation exchange capacity (CEC). Further independent validation gave r2≥0.73 and the ratio of prediction deviation (RPD) 4.4–2.1 for LL, LS, COLE, W, CEC, plastic limit (PL), plasticity index (PI), and volumetric shrinkage (VS). The independent validation likelihood ratios for the diagnostic screening tests were: LL>55%, 4.2; PI>30%, 2.7; LS>12%, 2.4; exchangeable sodium (eNa)>2cmol (+) kg−1, 2.3; exchangeable sodium percent (ESP)>10%, 1.8; W>8.3%, 1.6, and Activity number (A)>1.25units, 1.5. MIR can provide the rapid assessment of several soil properties that yield stability indices in material testing for engineering land use. Further studies should test the ability of MIR PLS for establishing broader calibrations across more diverse soil types and the direct correlation of MIR to material functional attributes

    Distributed organization of a brain microcircuit analyzed by three-dimensional modeling : the olfactory bulb

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    The functional consequences of the laminar organization observed in cortical systems cannot be easily studied using standard experimental techniques, abstract theoretical representations, or dimensionally reduced models built from scratch. To solve this problem we have developed a full implementation of an olfactory bulb microcircuit using realistic three-dimensional (3D) inputs, cell morphologies, and network connectivity. The results provide new insights into the relations between the functional properties of individual cells and the networks in which they are embedded. To our knowledge, this is the first model of the mitral-granule cell network to include a realistic representation of the experimentally-recorded complex spatial patterns elicited in the glomerular layer (GL) by natural odor stimulation. Although the olfactory bulb, due to its organization, has unique advantages with respect to other brain systems, the method is completely general, and can be integrated with more general approaches to other systems. The model makes experimentally testable predictions on distributed processing and on the differential backpropagation of somatic action potentials in each lateral dendrite following odor learning, providing a powerful 3D framework for investigating the functions of brain microcircuits

    A Study of the \eta \pi^{0} Spectrum and Search for a J^{PC} = 1^{-+} Exotic Meson

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    A partial wave analysis (PWA) of the of the ηπ0\eta \pi ^0 system (where ηγγ\eta \to \gamma \gamma) produced in the charge exchange reaction πpηπ0n\pi ^-p\to \eta \pi ^0n at an incident momentum of 18 GeV/c/c is presented as a function of ηπ0{\eta \pi ^0} invariant mass, mηπ0m_{\eta\pi^0}, and momentum transfer squared, tπηπt_{\pi^{-}\to\eta\pi}, from the incident π\pi^- to the outgoing ηπ0{\eta\pi ^0} system. SS, PP and DD waves were included in the PWA. The a0(980)a_0(980) and a2(1320)a_2(1320) states are clearly observed in the overall ηπ0{\eta\pi ^0} effective mass distribution as well as in the amplitudes associated with SS wave and DD waves respectively after partial wave decomposition. The observed distributions in moments (averages of spherical harmonics) were compared to the results from the PWA and the two are consistent. The distribution in tπηπt_{\pi^{-}\to\eta\pi} for individual DD waves associated with natural and unnatural parity exchange in the tt-channel are consistent with Regge phenomenology. Of particular interest in this study is the PP wave since this leads to an exotic JPC=1+J^{PC}=1^{-+} for the ηπ\eta \pi system. A PP wave is present in the data, however attempts to describe the mass dependence of the amplitude and phase motion with respect to the DD wave as a Breit-Wigner resonance are problematic. This has implications regarding the existence of a reported exotic JPC=1+J^{PC} = 1^{-+} meson decaying into ηπ0\eta \pi^0 with a mass near 1.4 GeV/c2/c^2.Comment: 19 pages, 29 figures, to appear in Phys. Rev.

    How brains make decisions

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    This chapter, dedicated to the memory of Mino Freund, summarizes the Quantum Decision Theory (QDT) that we have developed in a series of publications since 2008. We formulate a general mathematical scheme of how decisions are taken, using the point of view of psychological and cognitive sciences, without touching physiological aspects. The basic principles of how intelligence acts are discussed. The human brain processes involved in decisions are argued to be principally different from straightforward computer operations. The difference lies in the conscious-subconscious duality of the decision making process and the role of emotions that compete with utility optimization. The most general approach for characterizing the process of decision making, taking into account the conscious-subconscious duality, uses the framework of functional analysis in Hilbert spaces, similarly to that used in the quantum theory of measurements. This does not imply that the brain is a quantum system, but just allows for the simplest and most general extension of classical decision theory. The resulting theory of quantum decision making, based on the rules of quantum measurements, solves all paradoxes of classical decision making, allowing for quantitative predictions that are in excellent agreement with experiments. Finally, we provide a novel application by comparing the predictions of QDT with experiments on the prisoner dilemma game. The developed theory can serve as a guide for creating artificial intelligence acting by quantum rules.Comment: Latex file, 20 pages, 3 figure

    Aquatic food security:insights into challenges and solutions from an analysis of interactions between fisheries, aquaculture, food safety, human health, fish and human welfare, economy and environment

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    Fisheries and aquaculture production, imports, exports and equitability of distribution determine the supply of aquatic food to people. Aquatic food security is achieved when a food supply is sufficient, safe, sustainable, shockproof and sound: sufficient, to meet needs and preferences of people; safe, to provide nutritional benefit while posing minimal health risks; sustainable, to provide food now and for future generations; shock-proof, to provide resilience to shocks in production systems and supply chains; and sound, to meet legal and ethical standards for welfare of animals, people and environment. Here, we present an integrated assessment of these elements of the aquatic food system in the United Kingdom, a system linked to dynamic global networks of producers, processors and markets. Our assessment addresses sufficiency of supply from aquaculture, fisheries and trade; safety of supply given biological, chemical and radiation hazards; social, economic and environmental sustainability of production systems and supply chains; system resilience to social, economic and environmental shocks; welfare of fish, people and environment; and the authenticity of food. Conventionally, these aspects of the food system are not assessed collectively, so information supporting our assessment is widely dispersed. Our assessment reveals trade-offs and challenges in the food system that are easily overlooked in sectoral analyses of fisheries, aquaculture, health, medicine, human and fish welfare, safety and environment. We highlight potential benefits of an integrated, systematic and ongoing process to assess security of the aquatic food system and to predict impacts of social, economic and environmental change on food supply and demand

    A measurement of the tau mass and the first CPT test with tau leptons

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    We measure the mass of the tau lepton to be 1775.1+-1.6(stat)+-1.0(syst.) MeV using tau pairs from Z0 decays. To test CPT invariance we compare the masses of the positively and negatively charged tau leptons. The relative mass difference is found to be smaller than 3.0 10^-3 at the 90% confidence level.Comment: 10 pages, 4 figures, Submitted to Phys. Letts.

    Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays

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    The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the production flavour of the B0 mesons was determined using a combination of tags from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d = 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.

    First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons

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    We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/gamma* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/gamma* branching ratio to hadrons to be (0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)egamma* production, this product is found to be (4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters

    WW Production Cross Section and W Branching Fractions in e+e- Collisions at 189 GeV

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    From a data sample of 183 pb^-1 recorded at a center-of-mass energy of roots = 189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are selected. Assuming Standard Model W boson decay branching fractions, the W-pair production cross section is measured to be sigmaWW = 16.30 +- 0.34(stat.) +- 0.18(syst.) pb. When combined with previous OPAL measurements, the W boson branching fraction to hadrons is determined to be 68.32 +- 0.61(stat.) +- 0.28(syst.) % assuming lepton universality. These results are consistent with Standard Model expectations.Comment: 22 pages, 5 figures, submitted to Phys. Lett.

    Genuine Correlations of Like-Sign Particles in Hadronic Z0 Decays

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    Correlations among hadrons with the same electric charge produced in Z0 decays are studied using the high statistics data collected from 1991 through 1995 with the OPAL detector at LEP. Normalized factorial cumulants up to fourth order are used to measure genuine particle correlations as a function of the size of phase space domains in rapidity, azimuthal angle and transverse momentum. Both all-charge and like-sign particle combinations show strong positive genuine correlations. One-dimensional cumulants initially increase rapidly with decreasing size of the phase space cells but saturate quickly. In contrast, cumulants in two- and three-dimensional domains continue to increase. The strong rise of the cumulants for all-charge multiplets is increasingly driven by that of like-sign multiplets. This points to the likely influence of Bose-Einstein correlations. Some of the recently proposed algorithms to simulate Bose-Einstein effects, implemented in the Monte Carlo model PYTHIA, are found to reproduce reasonably well the measured second- and higher-order correlations between particles with the same charge as well as those in all-charge particle multiplets.Comment: 26 pages, 6 figures, Submitted to Phys. Lett.
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