7,809 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
Geometrical approach to tumor growth
Tumor growth has a number of features in common with a physical process known
as molecular beam epitaxy. Both growth processes are characterized by the
constraint of growth development to the body border, and surface diffusion of
cells/particles at the growing edge. However, tumor growth implies an
approximate spherical symmetry that makes necessary a geometrical treatment of
the growth equations. The basic model was introduced in a former article [C.
Escudero, Phys. Rev. E 73, 020902(R) (2006)], and in the present work we extend
our analysis and try to shed light on the possible geometrical principles that
drive tumor growth. We present two-dimensional models that reproduce the
experimental observations, and analyse the unexplored three-dimensional case,
for which new conclusions on tumor growth are derived
Optimal system size for complex dynamics in random neural networks near criticality
In this Letter, we consider a model of dynamical agents coupled through a
random connectivity matrix, as introduced in [Sompolinsky et. al, 1988] in the
context of random neural networks. It is known that increasing the disorder
parameter induces a phase transition leading to chaotic dynamics. We observe
and investigate here a novel phenomenon in the subcritical regime : the
probability of observing complex dynamics is maximal for an intermediate system
size when the disorder is close enough to criticality. We give a more general
explanation of this type of system size resonance in the framework of extreme
values theory for eigenvalues of random matrices.Comment: 11 pages, 2 figure
Enhancing quantum entanglement by photon addition and subtraction
The non-Gaussian operations effected by adding or subtracting a photon on the
entangled optical beams emerging from a parametric down-conversion process have
been suggested to enhance entanglement. Heralded photon addition or subtraction
is, as a matter of fact, at the heart of continuous-variable entanglement
distillation. The use of such processes has recently been experimentally
demonstrated in the context of the generation of optical coherent-state
superpositions or the verification of the canonical commutation relations.
Here, we carry out a systematic study of the effect of local photon additions
or subtractions on a two-mode squeezed vacuum state, showing that the
entanglement generally increases with the number of such operations. This is
analytically proven when additions or subtractions are restricted to one mode
only, while we observe that the highest entanglement is achieved when these
operations are equally shared between the two modes. We also note that adding
photons typically provides a stronger entanglement enhancement than subtracting
photons, while photon subtraction performs better in terms of energy
efficiency. Furthermore, we analyze the interplay between entanglement and
non-Gaussianity, showing that it is more subtle than previously expected.Comment: 10 pages, 6 figure
Influence of processing parameters on the recrystallized microstructure of extra-low-carbon steels
This article deals with the influence of processing parameters of a new procedure for ferritic rolling on the recrystallized microstructure of extra-low-carbon (ELC) steels. Parameters such as coil transfer temperature and degree of reduction during ferritic rolling are shown to control the morphology of cementite particles and the precipitation of AIN process. The recrystallized grain morphology and the percentage of recrystallization after annealing cycles simulating the industrial coiling process are shown to be strongly influenced by processing parameters.Peer Reviewe
Enabling Practical IPsec authentication for the Internet
On the Move to Meaningful Internet Systems 2006: OTM 2006 Workshops (First International Workshop on Information Security (IS'06), OTM Federated Conferences and workshops). Montpellier, Oct,/Nov. 2006There is a strong consensus about the need for IPsec, although its use is not widespread for end-to-end communications. One of the main reasons for this is the difficulty for authenticating two end-hosts that do not share a secret or do not rely on a common Certification Authority. In this paper we propose a modification to IKE to use reverse DNS and DNSSEC (named DNSSEC-to-IKE) to provide end-to-end authentication to Internet hosts that do not share any secret, without requiring the deployment of a new infrastructure. We perform a comparative analysis in terms of requirements, provided security and performance with state-of-the-art IKE authentication methods and with a recent proposal for IPv6 based on CGA. We conclude that DNSSEC-to-IKE enables the use of IPsec in a broad range of scenarios in which it was not applicable, at the price of offering slightly less security and incurring in higher performance costs.Universidad de Montpellier IIPublicad
The complexity of a numerical semigroup
Let S and Delta be numerical semigroups. A numerical semigroup S is an I(Delta)-semigroup if S \ {0} is an ideal of Delta. We denote by J (Delta) = {S vertical bar S is an I(Delta)-semigroupg, and we say that Delta is an ideal extension of S if S is an element of J (Delta). In this work, we present an algorithm to build all the ideal extensions of a numerical semigroup. We recursively denote by J(0) (N) = N; J(1)(N) = J (N) and J(k+1) (N) = J (J(k) (N)) for all k is an element of N: The complexity of a numerical semigroup S is the minimum of the set {k is an element of N vertical bar S is an element of J(k) (N)}. In addition, we introduce an algorithm to compute all the numerical semigroups with fixed multiplicity and complexity.Junta de Andalucia
MTM2017-84890-
A Theoretical Framework for Lagrangian Descriptors
This paper provides a theoretical background for Lagrangian Descriptors
(LDs). The goal of achieving rigourous proofs that justify the ability of LDs
to detect invariant manifolds is simplified by introducing an alternative
definition for LDs. The definition is stated for -dimensional systems with
general time dependence, however we rigorously prove that this method reveals
the stable and unstable manifolds of hyperbolic points in four particular 2D
cases: a hyperbolic saddle point for linear autonomous systems, a hyperbolic
saddle point for nonlinear autonomous systems, a hyperbolic saddle point for
linear nonautonomous systems and a hyperbolic saddle point for nonlinear
nonautonomous systems. We also discuss further rigorous results which show the
ability of LDs to highlight additional invariants sets, such as -tori. These
results are just a simple extension of the ergodic partition theory which we
illustrate by applying this methodology to well-known examples, such as the
planar field of the harmonic oscillator and the 3D ABC flow. Finally, we
provide a thorough discussion on the requirement of the objectivity
(frame-invariance) property for tools designed to reveal phase space structures
and their implications for Lagrangian descriptors
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