Adoption of healthcare information technology and the impact on clinician behavior

Thesis (S.M.)--Harvard-MIT Division of Health Sciences and Technology, 2009."June 2009." Cataloged from PDF version of thesis.Includes bibliographical references (p. 49-52).It is widely believed that healthcare information technology (health IT) can improve care and lower costs. However, the pattern and uptake of beneficial features of health IT is poorly understood, and is an important part of realizing the full benefits of health IT. This thesis examines the factors relating to adoption and use of reporting features within an outpatient practice management system. A retrospective observational study was performed utilizing web log data from a practice management and electronic health record system vendor. Two years of data were analyzed on the use of features within the system in two different scenarios: the use of a newly released custom reporting feature among existing clients, and the use of a physician-level monthly report among new clients. Among these two different populations and features, the first use and subsequent utilization exhibited similar patterns. Using the Bass model of technology diffusion to quantify the adoption of these features, it was found that adoption had a low social component (coefficient of imitation) and a high personal component (coefficient of innovation). One physician's use of a feature in his practice did not appear to influence whether a new physician joining the same practice would use the feature. In addition, the earliest users of a feature tended to utilize that feature more often. Practices and providers that used these features performed better across three of four operational and financial metrics. The purchase and installation of a health IT system by an organization does not ensure that individuals within it will fully utilize the system and realize all the benefits.(cont.) Incentives for health IT should focus on the advantages gained from these systems, and not merely on their purchase. Health IT vendors should be cognizant of the way they introduce new functionality to their clients in order to ensure maximal use.by Adam Weinstein.S.M

Spectral variational principle for Green's functions

For a suitable approximation ( q, q′, τ ) to the Dirac-Feynman Green's function of a quantummechanical system, the parameter is defined, where ℒ≡ i ∂/∂τ−ℋ. It is shown that Δ ≧0 and Δ →0 as K→K , the exact Green's function, thus providing a criterion on approximate Green's functions analogous in its role to the variational principle for wavefunctions. A second somewhat weaker criterion is also proposed, based on . Recipes are given for projecting out continuum contributions to Δ or ∑ and for analyzing for the discrete eigen-value spectrum. Um zu Näherungen ( q, q′, τ) für die Dirac-Feynman-Greensche Funktion eines quantenmechanischen Systems zu gelangen, wird der Parameter definiert, wobei ℒ≡ i ∂/∂τ−ℋ für iδ/δτ — ℋ steht. Es wird gezeigt, daß Δ ≧0 und Δ →0 wenn K→K , so daß damit ein Kriterium für Näherungen der Green'schen Funktion analog dem Variationsprinzip für Wellenfunktionen gefunden ist. Als zweites, wenn auch schwächeres Kriterium gründet sich auf . Hinweise für das Herausprojizieren der Beträge des Kontinuums aus Δ bzw. ∑ und für die Analyse des diskreten Spektrums werden gegeben.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46453/1/214_2004_Article_BF01007554.pd

Molecular vibration in cold collision theory

Cold collisions of ground state oxygen molecules with Helium have been investigated in a wide range of cold collision energies (from 1 $\mu$K up to 10 K) treating the oxygen molecule first as a rigid rotor and then introducing the vibrational degree of freedom. The comparison between the two models shows that at low energies the rigid rotor approximation is very accurate and able to describe all the dynamical features of the system. The comparison between the two models has also been extended to cases where the interaction potential He - O$_2$ is made artificially stronger. In this case vibration can perturb rate constants, but fine-tuning the rigid rotor potential can alleviate the discrepancies between the two models.Comment: 11 pages, 3 figure

Entanglement preparation using symmetric multiports

We investigate the entanglement produced by a multi-path interferometer that is composed of two symmetric multiports, with phase shifts applied to the output of the first multiport. Particular attention is paid to the case when we have a single photon entering the interferometer. For this situation we derive a simple condition that characterize the types of entanglement that one can generate. We then show how one can use the results from the single photon case to determine what kinds of multi-photon entangled states one can prepare using the interferometer.Comment: 6 pages, 2 figures, accepted for publication in European Journal of Physics

Entanglement preparation using symmetric multiports

We investigate the entanglement produced by a multi-path interferometer that is composed of two symmetric multiports, with phase shifts applied to the output of the first multiport. Particular attention is paid to the case when we have a single photon entering the interferometer. For this situation we derive a simple condition that characterize the types of entanglement that one can generate. We then show how one can use the results from the single photon case to determine what kinds of multi-photon entangled states one can prepare using the interferometer.Comment: 6 pages, 2 figures, accepted for publication in European Journal of Physics

Exploring \pp scattering in the \1N picture

In the large $N_c$ approximation to $QCD$, the leading \pp scattering amplitude is expressed as the sum of an infinite number of tree diagrams. We investigate the possibility that an adequate approximation at energies up to somewhat more than one $GeV$ can be made by keeping diagrams which involve the exchange of resonances in this energy range in addition to the simplest chiral contact terms. In this approach crossing symmetry is automatic but individual terms tend to drastically violate partial wave unitarity. We first note that the introduction of the $\rho$ meson in a chirally invariant manner substantially delays the onset of drastic unitarity violation which would be present for the {\it current algebra} term alone. This suggests a possibility of local (in energy) cancellation which we then explore in a phenomenological way. We include exchanges of leading resonances up to the $1.3 GeV$ region. However, unitarity requires more structure which we model by a four derivative contact term or by a low lying scalar resonance which is presumably subleading in the \1N expansion, but may nevertheless be important. The latter two flavor model gives a reasonable description of the phase shift $\delta^0_0$ up until around $860 MeV$, before the effects associated which the $K\bar{K}$ threshold come into play.Comment: 27 LaTex pages + 13 figures (also available in hard-copy

Discrete Nonholonomic Lagrangian Systems on Lie Groupoids

This paper studies the construction of geometric integrators for nonholonomic systems. We derive the nonholonomic discrete Euler-Lagrange equations in a setting which permits to deduce geometric integrators for continuous nonholonomic systems (reduced or not). The formalism is given in terms of Lie groupoids, specifying a discrete Lagrangian and a constraint submanifold on it. Additionally, it is necessary to fix a vector subbundle of the Lie algebroid associated to the Lie groupoid. We also discuss the existence of nonholonomic evolution operators in terms of the discrete nonholonomic Legendre transformations and in terms of adequate decompositions of the prolongation of the Lie groupoid. The characterization of the reversibility of the evolution operator and the discrete nonholonomic momentum equation are also considered. Finally, we illustrate with several classical examples the wide range of application of the theory (the discrete nonholonomic constrained particle, the Suslov system, the Chaplygin sleigh, the Veselova system, the rolling ball on a rotating table and the two wheeled planar mobile robot).Comment: 45 page

Asymptotic Density of Eigenvalue Clusters for the Perturbed Landau Hamiltonian

We consider the Landau Hamiltonian (i.e. the 2D Schroedinger operator with constant magnetic field) perturbed by an electric potential V which decays sufficiently fast at infinity. The spectrum of the perturbed Hamiltonian consists of clusters of eigenvalues which accumulate to the Landau levels. Applying a suitable version of the anti-Wick quantization, we investigate the asymptotic distribution of the eigenvalues within a given cluster as the number of the cluster tends to infinity. We obtain an explicit description of the asymptotic density of the eigenvalues in terms of the Radon transform of the perturbation potential V.Comment: 30 pages. The explicit dependence on B and V in Theorem 1.6 (i) - (ii) indicated. Typos corrected. To appear in Communications in Mathematical Physic

Integrable structure of Ginibre's ensemble of real random matrices and a Pfaffian integration theorem

In the recent publication [E. Kanzieper and G. Akemann, Phys. Rev. Lett. 95, 230201 (2005)], an exact solution was reported for the probability p_{n,k} to find exactly k real eigenvalues in the spectrum of an nxn real asymmetric matrix drawn at random from Ginibre's Orthogonal Ensemble (GinOE). In the present paper, we offer a detailed derivation of the above result by concentrating on the proof of the Pfaffian integration theorem, the key ingredient of our analysis of the statistics of real eigenvalues in the GinOE. We also initiate a study of the correlations of complex eigenvalues and derive a formula for the joint probability density function of all complex eigenvalues of a GinOE matrix restricted to have exactly k real eigenvalues. In the particular case of k=0, all correlation functions of complex eigenvalues are determined