332 research outputs found

    Dimensions and Determinants of Financialisation: Comparing OECD Countries since 1997

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    The financialisation literature has grown over the past decades. Despite a generally accepted definition, financialisation has been used to describe different phenomena. We distinguish between financialisation of non-financial companies, households and the financial sector and use activity and vulnerability measures. We identify seven financialisation hypotheses in the literature and empirically investigate them in a cross-country analysis for 17 OECD countries and two time periods, 1997–2007 as well as 2008–17. We find different financialisation measures are only weakly correlated, suggesting the existence of distinct financialisation processes. There is strong evidence that financialisation is linked to asset price inflation and correlated with a debt-driven demand regime. Financial deregulation encourages financialisation. There is limited evidence that market-based financial systems are more financialised. Foreign financial inflows do not seem a main driver. We do not find indication that an investment slowdown precedes financialisation. Our findings suggest financialisation should be understood as a variegated process, playing out differently across economic sectors and countries

    The Three-Nucleon System Near the N-d Threshold

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    The three-nucleon system is studied at energies a few hundred keV above the N-d threshold. Measurements of the tensor analyzing powers T20T_{20} and T21T_{21} for p-d elastic scattering at Ec.m.=432E_{c.m.}=432 keV are presented together with the corresponding theoretical predictions. The calculations are extended to very low energies since they are useful for extracting the p-d scattering lengths from the experimental data. The interaction considered here is the Argonne V18 potential plus the Urbana three-nucleon potential. The calculation of the asymptotic D- to S-state ratio for 3^3H and 3^3He, for which recent experimental results are available, is also presented.Comment: Latex, 11 pages, 2 figures, to be published in Phy.Lett.

    Precision Measurements of d(d,p)t and d(d,n)^3He Total Cross Sections at Big-Bang Nucleosynthesis Energies

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    Recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements have determined the baryon density of the Universe Ωb\Omega_b with a precision of about 4%. With Ωb\Omega_b tightly constrained, comparisons of Big Bang Nucleosynthesis (BBN) abundance predictions to primordial abundance observations can be made and used to test BBN models and/or to further constrain abundances of isotopes with weak observational limits. To push the limits and improve constraints on BBN models, uncertainties in key nuclear reaction rates must be minimized. To this end, we made new precise measurements of the d(d,p)t and d(d,n)^3He total cross sections at lab energies from 110 keV to 650 keV. A complete fit was performed in energy and angle to both angular distribution and normalization data for both reactions simultaneously. By including parameters for experimental variables in the fit, error correlations between detectors, reactions, and reaction energies were accurately tabulated by computational methods. With uncertainties around 2% +/- 1% scale error, these new measurements significantly improve on the existing data set. At relevant temperatures, using the data of the present work, both reaction rates are found to be about 7% higher than those in the widely used Nuclear Astrophysics Compilation of Reaction Rates (NACRE). These data will thus lead not only to reduced uncertainties, but also to modifications in the BBN abundance predictions.Comment: 15 pages, 11 figures, minor editorial change

    Effects of Thermal Stress on Dual Task Performance and Attention Allocation

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    A visual-visual dual task was designed to test the effect of the thermal environment on dual task performance and attention allocation. The temperatures selected for testing were 20 and 35°C Wet Bulb Globe Temperature (WBGT) in experiment 1 and 25, 30 and 35°C Wet Bulb Globe Temperature (WBGT) in experiment 2. In experiment 1, 34 volunteers were randomly assigned to one of the two temperature conditions. A variable representing accuracy on both tasks was coded such that a correct response was assigned only if the participant answered correctly on both tasks. In experiment 2, 42 volunteers were randomly assigned to one of three temperature conditions and instructed vary the amount of attention allocated to each task. Individual differences in single task performance were controlled by equating the baselines of single task performance. Once individual differences in single task capacity were controlled, statistically significant differences in performance were demonstrated. Mean accuracy was computed over a one-hour testing period in each temperature condition. Participants’ mean accuracy in the 35°C condition (38.18%) was substantially less than in the 20°C condition (50.88%). Further, statistically significant differences in performance were detected: in the ability to equally divide attention, effectively allocate attention, and in the relative divided attention cost under thermal stress

    Evidence for Three Nucleon Force Effects in p-d Elastic Scattering

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    A new measurement of the p-d differential cross section at Ep= 1 MeV has been performed. These new data and older data sets at energies below the deuteron breakup are compared to calculations using the two-nucleon Argonne v18 and the three-nucleon Urbana IX potentials. A quantitative estimate of the capability of these interactions to describe the data is given in terms of a chi^2 analysis. The chi^2 per datum drastically improves when the three-nucleon interaction is included in the Hamiltonian.Comment: 13 pages, 5 figures, to be published in Phys. Rev.

    Photoneutron reaction cross section measurements on 94Mo and 90Zr relevant to the p-process nucleosynthesis

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    The photodisintegration cross sections for the 94Mo({\gamma},n) and 90Zr({\gamma},n) reactions have been experimentally investigated with quasi-monochromatic photon beams at the High Intensity {\gamma}-ray Source (HI{\gamma}S) facility of the Triangle Universities Nuclear Laboratory (TUNL). The energy dependence of the photoneutron reaction cross sections was measured with high precision from the respective neutron emission thresholds up to 13.5 MeV. These measurements contribute to a broader investigation of nuclear reactions relevant to the understanding of the p-process nucleosynthesis. The results are compared with the predictions of Hauser-Feshbach statistical model calculations using two different models for the dipole {\gamma}-ray strength function. The resulting 94Mo({\gamma},n) and 90Zr({\gamma},n) photoneutron stellar reaction rates as a function of temperature in the typical range of interest for the p-process nucleosynthesis show how sensitive the photoneutron stellar reaction rate can be to the experimental data in the vicinity of the neutron threshold

    Low-energy p-d Scattering: High Precision Data, Comparisons with Theory, and Phase-Shift Analyses

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    Angular distributions of sigma(theta), A_y, iT_11, T_20, T_21, and T_22 have been measured for d-p scattering at E_c.m.=667 keV. This set of high-precision data is compared to variational calculations with the nucleon-nucleon potential alone and also to calculations including a three-nucleon (3N) potential. Agreement with cross-section and tensor analyzing power data is excellent when a 3N potential is used. However, a comparison between the vector analyzing powers reveals differences of approximately 40% in the maxima of the angular distributions which is larger than reported at higher energies for both p-d and n-d scattering. Single-energy phase-shift analyses were performed on this data set and a similar data set at E_c.m.=431.3 keV. The role of the different phase-shift parameters in fitting these data is discussed.Comment: 18 pages, 6 figure

    Proton-3^{3}He elastic scattering at low energies

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    We present new accurate measurements of the differential cross section σ(θ)\sigma(\theta) and the proton analyzing power AyA_{y} for proton-3^{3}He elastic scattering at various energies. A supersonic gas jet target has been employed to obtain these low energy cross section measurements. The σ(θ)\sigma(\theta) distributions have been measured at EpE_{p} = 0.99, 1.59, 2.24, 3.11, and 4.02 MeV. Full angular distributions of AyA_{y} have been measured at EpE_{p} = 1.60, 2.25, 3.13, and 4.05 MeV. This set of high-precision data is compared to four-body variational calculations employing realistic nucleon-nucleon (NN) and three-nucleon (3N) interactions. For the unpolarized cross section the agreement between the theoretical calculation and data is good when a 3N3N potential is used. The comparison between the calculated and measured proton analyzing powers reveals discrepancies of approximately 50% at the maximum of each distribution. This is analogous to the existing ``AyA_{y} Puzzle'' known for the past 20 years in nucleon-deuteron elastic scattering.Comment: 22 pages, 9 figures, to be published in Physical Review C, corrected reference 4

    Bellman equations for optimal feedback control of qubit states

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    Using results from quantum filtering theory and methods from classical control theory, we derive an optimal control strategy for an open two-level system (a qubit in interaction with the electromagnetic field) controlled by a laser. The aim is to optimally choose the laser's amplitude and phase in order to drive the system into a desired state. The Bellman equations are obtained for the case of diffusive and counting measurements for vacuum field states. A full exact solution of the optimal control problem is given for a system with simpler, linear, dynamics. These linear dynamics can be obtained physically by considering a two-level atom in a strongly driven, heavily damped, optical cavity.Comment: 10 pages, no figures, replaced the simpler model in section
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