1,219 research outputs found
Via Hexagons to Squares in Ferrofluids: Experiments on Hysteretic Surface Transformations under Variation of the Normal Magnetic Field
We report on different surface patterns on magnetic liquids following the
Rosensweig instability. We compare the bifurcation from the flat surface to a
hexagonal array of spikes with the transition to squares at higher fields. From
a radioscopic mapping of the surface topography we extract amplitudes and
wavelengths. For the hexagon--square transition, which is complex because of
coexisting domains, we tailor a set of order parameters like peak--to--peak
distance, circularity, angular correlation function and pattern specific
amplitudes from Fourier space. These measures enable us to quantify the smooth
hysteretic transition. Voronoi diagrams indicate a pinning of the domains. Thus
the smoothness of the transition is roughness on a small scale.Comment: 17 pages, 14 figure
An Investigation of Coach Behaviors, Goal Motives, and Implementation Intentions as Predictors of Well-Being in Sport
The present study aimed to expand upon Smith, Ntoumanis, and Dudaâs (2007) research by investigating the influence of coach behaviors and implementation intentions on goal striving in sport. Structural equation modeling analysis with a sample of 108 athletes revealed coach behaviors as predictors of goal motives, which in turn predicted psychological well-being after 8 weeks. Supplementary regression analyses showed no interaction between autonomous goal motives and implementation intentions; however, a synergistic effect was identified for controlled goal motives such that controlled motives furnished with implementation intentions resulted in lower well-being than controlled motives alone. In further analyses, the motives underlying an implementation intention were found to mediate the paths from goal motives to well-being. The findings are discussed in terms of the roles played by goal motives, implementation intentions, and implementation intention motives during goal striving
Boson-conserving one-nucleon transfer operator in the interacting boson model
The boson-conserving one-nucleon transfer operator in the interacting boson
model (IBA) is reanalyzed. Extra terms are added to the usual form used for
that operator. These new terms change generalized seniority by one unit, as the
ones considered up to now. The results obtained using the new form for the
transfer operator are compared with those obtained with the traditional form in
a simple case involving the pseudo-spin Bose-Fermi symmetry in its limit. Sizeable differences are
found. These results are of relevance in the study of transfer reactions to
check nuclear supersymmetry and in the description of (\beta)-decay within IBA.Comment: 13 pages, 1 table, 0 figures. To be published in Phys. Rev.
E835 at FNAL: Charmonium Spectroscopy in Annihilations
I present preliminary results on the search for in its
and decay modes. We observe an excess of \eta_c\gamma{\cal P} \sim 0.001M=3525.8 \pm 0.2 \pm 0.2
\Gamma\leq10.6\pm 3.7\pm3.4(br) <
\Gamma_{\bar{p}p}B_{\eta_c\gamma} < 12.8\pm 4.8\pm4.5(br) J/\psi\pi^0$ mode.Comment: Presented at the 6th International Conference on Hyperons, Charm and
Beauty Hadrons (BEACH 2004), Chicago(Il), June 27-July 3,200
Measuring the deformation of a ferrogel sphere in a homogeneous magnetic field
A sphere of a ferrogel is exposed to a homogeneous magnetic field. In
accordance to theoretical predictions, it gets elongated along the field lines.
The time-dependence of the elastic shear modulus causes the elongation to
increase with time analogously to mechanic creep experiments, and the rapid
excitation causes the sphere to vibrate. Both phenomena can be well described
by a damped harmonic oscillator model. By comparing the elongation along the
field with the contraction perpendicular to it, we can calculate Poisson's
ratio of the gel. The magnitude of the elongation is compared with the
theoretical predictions for elastic spheres in homogeneous fields.Comment: 5 pages, 8 figure
Interference Study of the chi_c0 (1^3P_0) in the Reaction Proton-Antiproton -> pi^0 pi^0
Fermilab experiment E835 has observed proton-antiproton annihilation
production of the charmonium state chi_c0 and its subsequent decay into pi^0
pi^0. Although the resonant amplitude is an order of magnitude smaller than
that of the non-resonant continuum production of pi^0 pi^0, an enhanced
interference signal is evident. A partial wave expansion is used to extract
physics parameters. The amplitudes J=0 and 2, of comparable strength, dominate
the expansion. Both are accessed by L=1 in the entrance proton-antiproton
channel. The product of the input and output branching fractions is determined
to be B(pbar p -> chi_c0) x B(chi_c0 -> pi^0 pi^0)= (5.09 +- 0.81 +- 0.25) x
10^-7.Comment: 4 pages, 4 figures, Accepted by PRL (July 2003
Entwicklung und Ungleichheit von FÀhigkeiten : Anmerkungen aus ökonomischer Sicht
Nirgends sonst im ökonomischen Handeln fallen Kosten und Nutzen im Zeitablauf und aufgeteilt nach Investoren und NutznieĂern so eklatant auseinander wie bei Bildungsinvestitionen. In dem vorliegenden Beitrag wird argumentiert, dass in der sozialen RealitĂ€t die Bildungsungleichheit im Vorschulalter eine der wichtigsten Ursachen fĂŒr die Ungleichheit von FĂ€higkeiten und Kompetenzen auch im Schulalter und im Erwerbsleben ist. FĂŒr benachteiligte Kinder scheint somit die Bildungsungleichheit vor dem Schulalter bei uns, ebenso wie in anderen LĂ€ndern mit hohen Bildungsausgaben und hoher Wirtschaftskraft ihren schicksalhaften Charakter noch keineswegs verloren zu haben. Um dies zu Ă€ndern, bleibt es eine vordringliche Aufgabe auch der Bildungspolitik, den Zugang zu einer angemessenen emotionalen FĂŒrsorge von Anfang an weiter zu verbessern. DarĂŒber hinaus ist es notwendig, den betroffenen Kindern bis ins Jugendalter altersgemÀà und individuell zur Seite zu stehen
Precision measurements of the total and partial widths of the psi(2S) charmonium meson with a new complementary-scan technique in antiproton-proton annihilations
We present new precision measurements of the psi(2S) total and partial widths
from excitation curves obtained in antiproton-proton annihilations by Fermilab
experiment E835 at the Antiproton Accumulator in the year 2000. A new technique
of complementary scans was developed to study narrow resonances with
stochastically cooled antiproton beams. The technique relies on precise
revolution-frequency and orbit-length measurements, while making the analysis
of the excitation curve almost independent of machine lattice parameters. We
study the psi(2S) meson through the processes pbar p -> e+ e- and pbar p ->
J/psi + X -> e+ e- + X. We measure the width to be Gamma = 290 +- 25(sta) +-
4(sys) keV and the combination of partial widths Gamma_e+e- * Gamma_pbarp /
Gamma = 579 +- 38(sta) +- 36(sys) meV, which represent the most precise
measurements to date.Comment: 17 pages, 3 figures, 3 tables. Final manuscript accepted for
publication in Phys. Lett. B. Parts of the text slightly expanded or
rearranged; results are unchange
Improving the delivery of care for patients with diabetes through understanding optimised team work and organisation in primary care
Peer reviewedPublisher PD
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