15,766 research outputs found
Managing Waiting Times to Predict No-shows and Cancelations at a Children’s Hospital
Purpose: Since long waits in hospitals have been found to be related to high rates of no-shows and cancelations, managing waiting times should be considered as an important tool that hospitals can use to reduce missed appointments. The aim of this study is to analyze patients’ behavior in order to predict no-show and cancelation rates correlated to waiting times.
Design/methodology/approach: This study is based on the data from a US children’s hospital, which includes all the appointments registered during one year of observation. We used the call-appointment interval to establish the wait time to get an appointment. Four different types of appointment-keeping behavior and two types of patients were distinguished: arrival, no-show, cancelation with no reschedule, and cancelation with reschedule; and new and established patients.
Findings: Results confirmed a strong impact of long waiting times on patients’ appointment-keeping behavior, and the logarithmic regression was found as the best-fit function for the correlation between variables in all cases. The correlation analysis showed that new patients tend to miss appointments more often than established patients when the waiting time increases. It was also found that, depending on the patients’ appointment distribution, it might get more complicated for hospitals to reduce missed appointments as the waiting time is reduced.
Originality/value: The methodology applied in our study, which combines the use of regression analysis and patients’ appointment distribution analysis, would help health care managers to understand the initial implications of long waiting times and to address improvement related to patient satisfaction and hospital performance.Peer Reviewe
Quantum Hamiltonians with Quasi-Ballistic Dynamics and Point Spectrum
Consider the family of Schr\"odinger operators (and also its Dirac version)
on or where is a
transformation on (compact metric) , a real Lipschitz function and
a (sufficiently fast) power-decaying perturbation. Under certain conditions
it is shown that presents quasi-ballistic dynamics for
in a dense set. Applications include potentials generated
by rotations of the torus with analytic condition on , doubling map, Axiom A
dynamical systems and the Anderson model. If is a rank one perturbation,
examples of with quasi-ballistic dynamics and point spectrum
are also presented.Comment: 17 pages; to appear in Journal of Differential Equation
Dynamical Delocalization for the 1D Bernoulli Discrete Dirac Operator
An 1D tight-binding version of the Dirac equation is considered; after
checking that it recovers the usual discrete Schr?odinger equation in the
nonrelativistic limit, it is found that for two-valued Bernoulli potentials the
zero mass case presents absence of dynamical localization for specific values
of the energy, albeit it has no continuous spectrum. For the other energy
values (again excluding some very specific ones) the Bernoulli Dirac system is
localized, independently of the mass.Comment: 9 pages, no figures - J. Physics A: Math. Ge
Dynamical Lower Bounds for 1D Dirac Operators
Quantum dynamical lower bounds for continuous and discrete one-dimensional
Dirac operators are established in terms of transfer matrices. Then such
results are applied to various models, including the Bernoulli-Dirac one and,
in contrast to the discrete case, critical energies are also found for the
continuous Dirac case with positive mass.Comment: 18 pages; to appear in Math.
Two repelling random walks on
We consider two interacting random walks on such that the
transition probability of one walk in one direction decreases exponentially
with the number of transitions of the other walk in that direction. The joint
process may thus be seen as two random walks reinforced to repel each other.
The strength of the repulsion is further modulated in our model by a parameter
. When both processes are independent symmetric
random walks on , and hence recurrent. We show that both random
walks are further recurrent if . We also show that these
processes are transient and diverge in opposite directions if . The
case remains widely open. Our results are obtained by
considering the dynamical system approach to stochastic approximations.Comment: 17 pages. Added references and corrected typos. Revised the argument
for the convergence to equilibria of the vector field. Improved the proof for
the recurrence when beta belongs to (0,1); leading to the removal of a
previous conjectur
Stable retrograde orbits around the triple system 2001 SN263
The NEA 2001 SN263 is the target of the ASTER MISSION - First Brazilian Deep
Space Mission. Araujo et al. (2012), characterized the stable regions around
the components of the triple system for the planar and prograde cases. Knowing
that the retrograde orbits are expected to be more stable, here we present a
complementary study. We now considered particles orbiting the components of the
system, in the internal and external regions, with relative inclinations
between , i.e., particles with retrograde
orbits. Our goal is to characterize the stable regions of the system for
retrograde orbits, and then detach a preferred region to place the space probe.
For a space mission, the most interesting regions would be those that are
unstable for the prograde cases, but stable for the retrograde cases. Such
configuration provide a stable region to place the mission probe with a
relative retrograde orbit, and, at the same time, guarantees a region free of
debris since they are expected to have prograde orbits. We found that in fact
the internal and external stable regions significantly increase when compared
to the prograde case. For particles with and , we found
that nearly the whole region around Alpha and Beta remain stable. We then
identified three internal regions and one external region that are very
interesting to place the space probe. We present the stable regions found for
the retrograde case and a discussion on those preferred regions. We also
discuss the effects of resonances of the particles with Beta and Gamma, and the
role of the Kozai mechanism in this scenario. These results help us understand
and characterize the stability of the triple system 2001 SN263 when retrograde
orbits are considered, and provide important parameters to the design of the
ASTER mission.Comment: 11 pages, 8 figures. Accepted for publication in MNRAS - 2015 March
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