3,024 research outputs found
Taylor-Lagrange renormalization scheme. Application to light-front dynamics
The recently proposed renormalization scheme based on the definition of field
operators as operator valued distributions acting on specific test functions is
shown to be very convenient in explicit calculations of physical observables
within the framework of light-front dynamics. We first recall the main
properties of this procedure based on identities relating the test functions to
their Taylor remainder of any order expressed in terms of Lagrange's formulae,
hence the name given to this scheme. We thus show how it naturally applies to
the calculation of state vectors of physical systems in the covariant
formulation of light-front dynamics. As an example, we consider the case of the
Yukawa model in the simple two-body Fock state truncation.Comment: 18 pages, 6 figures, introduction changed, corrected typos, to be
published in Physical Review
Telemedicine of family-based treatment for adolescent anorexia nervosa: A protocol of a treatment development study.
BackgroundFamily-based treatment is an efficacious treatment available for adolescents with anorexia nervosa. Yet the implementation of this treatment, at least in the United States, is challenging due to a limited number of trained family-based treatment therapists and the concentration of these therapists in a limited number of urban centers. The use of telemedicine in the delivery of family-based treatment can increase access to this therapy for this patient population.Methods/designThis two-year treatment development study (December 2013-November 2015) follows a two-wave iterative case series design. The study is ongoing and addresses the treatment needs of families in remote, rural, or underrepresented parts of the United States by delivering family-based treatment via telemedicine (video chat). The first six months of the study was dedicated to selecting a cloud-based secure telemedicine portal for use with participants. Recruitment for the first of two consecutive case series (N = 5) began during month seven. After these five patients completed treatment, a systematic review of treatment via feedback from participants and therapists related to the delivery of this model and use of technology was completed. A second wave of recruitment is underway (N = 5). At the end of both waves (N = 10), and after a second review of treatment, we should be able to establish the feasibility and acceptability of family-based treatment delivered via telemedicine for this patient population.DiscussionThis study is the first attempt to deliver family-based treatment for adolescents with anorexia nervosa via telemedicine. If delivering family-based treatment in this format is feasible, it will provide access to an evidence-based treatment for families heretofore unable to participate in specialist treatment for their child's eating disorder
Pretreatment cognitive and neural differences between sapropterin dihydrochloride responders and non-responders with phenylketonuria
Sapropterin dihydrochloride (BH4) reduces phenylalanine (Phe) levels and improves white matter integrity in a subset of individuals with phenylketonuria (PKU) known as “responders.” Although prior research has identified biochemical and genotypic differences between BH4 responders and non-responders, cognitive and neural differences remain largely unexplored. To this end, we compared intelligence and white matter integrity prior to treatment with BH4 in 13 subsequent BH4 responders with PKU, 16 subsequent BH4 non-responders with PKU, and 12 healthy controls. Results indicated poorer intelligence and white matter integrity in non-responders compared to responders prior to treatment. In addition, poorer white matter integrity was associated with greater variability in Phe across the lifetime in non-responders but not in responders. These results underscore the importance of considering PKU as a multi-faceted, multi-dimensional disorder and point to the need for additional research to delineate characteristics that predict response to treatment with BH4
A Web/Grid Services Approach for Integration of Virtual Clinical & Research Environments
Clinicans have responsibilities for audit and research, often participating in projects with basic scientist colleagues. Our work in a regional teaching hospital setting involves collaboration with the medical school computer services and builds upon work developed in computer science department as part of the Collaborative Orthopaedic Research Environment (CORE) project[1]. This has established a pilot study for proof of concept work. Users are mapped to a personal profile implemented using XML and a service oriented architecture (SOA)[2,3]. This bridges the e-Health and e-Science domains, addressing some of the basic questions of security and uptake
The Commission and Its Report: Public Education, Advocacy and Lobbying
Mr. Harris: The question concerning the justification of commissions of inquiry has been raised in the preceding discussions. If their sole justification is having the bulk of their recommendations implemented, the institution probably would have died out long ago. Nevertheless, it must be of considerable concern to commissioners that the record has not been good in terms of implementation and one of the questions that perhaps will determine how successful commissions are in this respect has to do with what happens when the report is delivered and thereafter. These questions will be largely the subject of the panel that we are about to present. You will not be treated to profound, scholarly papers on policy analysis or anything like that in this panel. There will be practical comments and suggestions
Estimating turbulent velocities in the elliptical galaxies NGC 5044 and NGC 5813
The interstellar and intra-cluster medium in giant elliptical galaxies and
clusters of galaxies is often assumed to be in hydrostatic equilibrium.
Numerical simulations, however, show that about 5-30% of the pressure in a
cluster is provided by turbulence induced by, for example, the central AGN and
merger activity. We aim to put constraints on the turbulent velocities and
turbulent pressure in the ICM of the giant elliptical galaxies NGC 5044 and NGC
5813 using XMM-Newton RGS observations. The magnitude of the turbulence is
estimated using the Fe XVII lines at 15.01 A, 17.05 A, and 17.10 A in the RGS
spectra. At low turbulent velocities, the gas becomes optically thick in the
15.01 A line due to resonant scattering, while the 17 A lines remain optically
thin. By comparing the (I(17.05)+I(17.10))/I(15.01) line ratio from RGS with
simulated line ratios for different Mach numbers, the level of turbulence is
constrained. The measurement is limited by systematic uncertainties in the
atomic data, which are at the 20-30% level. We find that the line ratio in NGC
5813 is significantly higher than in NGC 5044. This difference can be explained
by a higher level of turbulence in NGC 5044. The high turbulent velocities and
the fraction of the turbulent pressure support of >40% in NGC 5044, assuming
isotropic turbulence, confirm that it is a highly disturbed system, probably
due to an off-axis merger. The turbulent pressure support in NGC 5813 is more
modest at 15-45%. The (I(17.05)+I(17.10))/I(15.01) line ratio in an optically
thin plasma, calculated using AtomDB v2.0.1, is 2 sigma above the ratio
measured in NGC 5044, which cannot be explained by resonant scattering. This
shows that the discrepancies between theoretical, laboratory, and astrophysical
data on Fe XVII lines need to be reduced to improve the accuracy of the
determination of turbulent velocities using resonant scattering.Comment: 11 pages, 5 figures, accepted for publication in A&
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