28,390 research outputs found
TRUSTWORTHINESS AS AN ECONOMIC ASSET
The evaluation of trust in economic decision making remains on the periphery of mainstream economic analysis and teaching. Yet business managers use trustworthiness in daily exchanges to create competitive advantages for their firms. An exploratory empirical test of Barney and HansenÂ’s three levels of trust (weak, semistrong, and strong) and Lewicki and BunkerÂ’s portfolio of governance mechanisms revealed that strong-form trust exists in day-to-day business relationships along with other governance mechanisms. Identity-based transactions were more prevalent than were weak trust market exchanges in important economic transactions.Institutional and Behavioral Economics, International Relations/Trade,
Coplanar Circumbinary Debris Disks
We present resolved Herschel images of circumbinary debris disks in the alpha
CrB (HD139006) and beta Tri (HD13161) systems. We find that both disks are
consistent with being aligned with the binary orbital planes. Though secular
perturbations from the binary can align the disk, in both cases the alignment
time at the distances at which the disk is resolved is greater than the stellar
age, so we conclude that the coplanarity was primordial. Neither disk can be
modelled as a narrow ring, requiring extended radial distributions. To satisfy
both the Herschel and mid-IR images of the alpha CrB disk, we construct a model
that extends from 1-300AU, whose radial profile is broadly consistent with a
picture where planetesimal collisions are excited by secular perturbations from
the binary. However, this model is also consistent with stirring by other
mechanisms, such as the formation of Pluto-sized objects. The beta Tri disk
model extends from 50-400AU. A model with depleted (rather than empty) inner
regions also reproduces the observations and is consistent with binary and
other stirring mechanisms. As part of the modelling process, we find that the
Herschel PACS beam varies by as much as 10% at 70um and a few % at 100um. The
70um variation can therefore hinder image interpretation, particularly for
poorly resolved objects. The number of systems in which circumbinary debris
disk orientations have been compared with the binary plane is now four. More
systems are needed, but a picture in which disks around very close binaries
(alpha CrB, beta Tri, and HD 98800, with periods of a few weeks to a year) are
aligned, and disks around wider binaries (99 Her, with a 50 yr period) are
misaligned, may be emerging. This picture is qualitatively consistent with the
expectation that the protoplanetary disks from which the debris emerged are
more likely to be aligned if their binaries have shorter periods.Comment: accepted to MNRA
Transforming fixed-length self-avoiding walks into radial SLE_8/3
We conjecture a relationship between the scaling limit of the fixed-length
ensemble of self-avoiding walks in the upper half plane and radial SLE with
kappa=8/3 in this half plane from 0 to i. The relationship is that if we take a
curve from the fixed-length scaling limit of the SAW, weight it by a suitable
power of the distance to the endpoint of the curve and then apply the conformal
map of the half plane that takes the endpoint to i, then we get the same
probability measure on curves as radial SLE. In addition to a non-rigorous
derivation of this conjecture, we support it with Monte Carlo simulations of
the SAW. Using the conjectured relationship between the SAW and radial SLE, our
simulations give estimates for both the interior and boundary scaling
exponents. The values we obtain are within a few hundredths of a percent of the
conjectured values
Transmission resonances and supercritical states in a one dimensional cusp potential
We solve the two-component Dirac equation in the presence of a spatially one
dimensional symmetric cusp potential. We compute the scattering and bound
states solutions and we derive the conditions for transmission resonances as
well as for supercriticality.Comment: 10 pages. Revtex 4. To appear in Phys Rev.
The Length of an SLE - Monte Carlo Studies
The scaling limits of a variety of critical two-dimensional lattice models
are equal to the Schramm-Loewner evolution (SLE) for a suitable value of the
parameter kappa. These lattice models have a natural parametrization of their
random curves given by the length of the curve. This parametrization (with
suitable scaling) should provide a natural parametrization for the curves in
the scaling limit. We conjecture that this parametrization is also given by a
type of fractal variation along the curve, and present Monte Carlo simulations
to support this conjecture. Then we show by simulations that if this fractal
variation is used to parametrize the SLE, then the parametrized curves have the
same distribution as the curves in the scaling limit of the lattice models with
their natural parametrization.Comment: 18 pages, 10 figures. Version 2 replaced the use of "nu" for the
"growth exponent" by 1/d_H, where d_H is the Hausdorff dimension. Various
minor errors were also correcte
Finite Density Algorithm in Lattice QCD -- a Canonical Ensemble Approach
I will review the finite density algorithm for lattice QCD based on finite
chemical potential and summarize the associated difficulties. I will propose a
canonical ensemble approach which projects out the finite baryon number sector
from the fermion determinant. For this algorithm to work, it requires an
efficient method for calculating the fermion determinant and a Monte Carlo
algorithm which accommodates unbiased estimate of the probability. I shall
report on the progress made along this direction with the Pad\'{e} - Z
estimator of the determinant and its implementation in the newly developed
Noisy Monte Carlo algorithm.Comment: Invited talk at Nankai Symposium on Mathematical Physics, Tianjin,
Oct. 2001, 18 pages, 3 figures; expanded and references adde
Mott transition in lattice boson models
We use mathematically rigorous perturbation theory to study the transition
between the Mott insulator and the conjectured Bose-Einstein condensate in a
hard-core Bose-Hubbard model. The critical line is established to lowest order
in the tunneling amplitude.Comment: 20 page
A COMPARISON OF PRE- AND POST-OPERATIVE THREE-DIMENSIONAL HIP KINEMATICS DURING LEVEL WALKING IN PATIENTS WITH CAM FEMOROACETABULAR IMPINGEMENT
Cam femoroacetabular impingement (FAI) is an idiopathic progressive pathological condition of the hip joint characterized by an abnormal bony protuberance on the femoral head-neck junction (Beck, Leunig, Parvizi, Boutier, Wyss & Ganz, 2004). During the limits of hip range of motion (ROM), the protuberance jams into the acetabulum (Ganz, Parvizi, Beck, Leunig, Nötzli & Siebenrock, 2003), resulting in acute hip and groin pain (Beaulé, LeDuff, & Zaragoza, 2007). Impingement has also been shown to occur within normal ROM of the hip during basic tasks such as walking, reducing peak hip abduction angles as well as hip frontal and sagittal ROM (Kennedy, Lamontagne & Beaulé, 2009). Cam FAI primarily affects young and athletic males (Ganz, Parvizi, Beck, Leunig, Nötzli & Siebenrock, 2003), and is common in hockey, football, soccer, rugby, martial arts and tennis athletes (Philippon, Schenker, Briggs & Kuppersmith, 2007). Restricted hip mobility during activities requiring low ROM suggests more pronounced limitations during demanding athletic tasks. Surgical procedures have been developed to remove the bony abnormality from the femoral head-neck junction with the objective of attenuating hip pain and restoring normal hip biomechanics, enabling athletes to return to sport. The purpose of this study is to assess the clinical outcome of cam FAI corrective surgery by comapring pre-operative and post-operative three-dimensional (3-D) hip kinematics during level walking
A new look at C*-simplicity and the unique trace property of a group
We characterize when the reduced C*-algebra of a group has unique tracial
state, respectively, is simple, in terms of Dixmier-type properties of the
group C*-algebra. We also give a simple proof of the recent result by
Breuillard, Kalantar, Kennedy and Ozawa that the reduced C*-algebra of a group
has unique tracial state if and only if the amenable radical of the group is
trivial.Comment: 8 page
Charge-ordered ferromagnetic phase in manganites
A mechanism for charge-ordered ferromagnetic phase in manganites is proposed.
The mechanism is based on the double exchange in the presence of diagonal
disorder. It is modeled by a combination of the Ising double-exchange and the
Falicov-Kimball model. Within the dynamical mean-field theory the charge and
spin correlation function are explicitely calculated. It is shown that the
system exhibits two successive phase transitions. The first one is the
ferromagnetic phase transition, and the second one is a charge ordering. As a
result a charge-ordered ferromagnetic phase is stabilized at low temperature.Comment: To appear in Phys. Rev.
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