31,377 research outputs found
Assessing and enhancing quality through outcomes-based continuing professional development (CPD): a review of current practice
Numerous professional bodies have questioned whether traditional input-based continuing professional development (CPD) schemes are effective at measuring genuine learning and improving practice performance and patient health. The most commonly used type of long-established CPD activities, such as conferences, lectures and symposia, have been found to have a limited effect on improving practitioner competence and performance, and no significant effect on patient health outcomes. Additionally, it is thought that the impact of many CPD activities is reduced when they are undertaken in isolation outside of a defined structure of directed learning. In contrast, CPD activities which are interactive, encourage reflection on practice, provide opportunities to practice skills, involve multiple exposures, help practitioners to identify between current performance and a standard to be achieved, and are focused on outcomes, are the most effective at improving practice and patient health outcomes
Relativistic models of the universe with pressure equal to zero and time-dependent uniformity
Zero density and approximate, relativistic models of univers
Electromagnetic Scattering from Relativistic Bound States
The quasipotential formalism for elastic scattering from relativistic bound
states is formulated based on the instant constraint in the Breit frame. The
quasipotential electromagnetic current is derived from Mandelstam's five-point
kernel and obeys a two-body Ward identity. Breit-frame wave functions are
obtained directly by solving integral equations with nonzero total
three-momentum, thus accomplishing a dynamical boost. Calculations of
electron-deuteron elastic form factors illustrate the importance of the
dynamical boost versus kinematic boosts of the rest frame wave functions.Comment: RevTeX 3.0 manuscript, 9 pages. UU-file is a single PostScript file
of the manuscript including figures. U. MD PP #93-17
Mercury in the environment
Problems in assessing mercury concentrations in environmental materials are discussed. Data for situations involving air, water, rocks, soils, sediments, sludges, fossil fuels, plants, animals, foods, and man are drawn together and briefly evaluated. Details are provided regarding the toxicity of mercury along with tentative standards and guidelines for mercury in air, drinking water, and food
Publications of the NASA CELSS (Controlled Ecological Life Support Systems) program
Publications on research sponsored by the NASA CELSS (controlled ecological life support systems) Program are listed. The bibliography is divided into four areas: (1) human requirements; (2) food production; (3) waste management; and (4) system management and control. The 210 references cover the period from the inception of the CELSS Program (1979) to the present, as well as some earlier publications during the development of the CELSS Program
Instant Two-Body Equation in Breit Frame
A quasipotential formalism for elastic scattering from relativistic bound
states is based on applying an instant constraint to both initial and final
states in the Breit frame. This formalism is advantageous for the analysis of
electromagnetic interactions because current conservation and four momentum
conservation are realized within a three-dimensional formalism. Wave functions
are required in a frame where the total momentum is nonzero, which means that
the usual partial wave analysis is inapplicable. In this work, the
three-dimensional equation is solved numerically, taking into account the
relevant symmetries. A dynamical boost of the interaction also is needed for
the instant formalism, which in general requires that the boosted interaction
be defined as the solution of a four-dimensional equation. For the case of a
scalar separable interaction, this equation is solved and the Lorentz
invariance of the three-dimensional formulation using the boosted interaction
is verified. For more realistic interactions, a simple approximation is used to
characterize the boost of the interaction.Comment: 20 pages in revtex 3, 3 figures. Fixed reform/tex errors
Transition from hadronic to partonic interactions for a composite spin-1/2 model of a nucleon
A simple model of a composite nucleon is developed in which a fermion and aboson, representing quark and diquark constituents of the nucleon, form a boundstate owing to a contact interaction. Photon and pion couplings to the quarkprovide vertex functions for the photon and pion interactions with thecomposite nucleon. By a suitable choice of cutoff parameters of the model,realistic electromagnetic form factors are obtained. When a pseudoscalarpion-quark coupling is used, the pion-nucleon coupling is predominantlypseudovector. A virtual photopion amplitude is considered in which there aretwo types of contributions: hadronic contributions where the photon and pioninteractions have an intervening propagator of the nucleon or its excitedstates, and contact-like contributions where the photon and pion interactionsoccur within a single vertex. At large Q, the contact-like contributions aredominant. The model nucleon exhibits scaling behavior in deep-inelasticscattering and the normalization of the parton distribution provides a roughnormalization of the contact-like contributions. Calculations for the virtualphotopion amplitude are performed using kinematics appropriate to itsoccurrence as a meson-exchange current in electron-deuteron scattering. Theresults show that the contact-like terms can dominate the meson-exchangecurrent for Q > 1 GeV/c. There is a direct connection of the contact-like termsto the off-forward parton distributions of the model nucleon
Evidence for Rotation in the Galaxy at z=3.15 Responsible for a Damped Lyman-alpha Absorption System in the Spectrum of Q2233+1310
Proof of the existence of a significant population of normal disk galaxies at
redshift z>2 would have profound implications for theories of structure
formation and evolution. We present evidence based on Keck HIRES observations
that the damped Lyman-alpha absorber at z=3.15 toward the quasar Q2233+1310 may
well be such an example. Djorgovski et al have recently detected the
Lyman-alpha emission from the absorber, which we assume is at the systemic
redshift of the absorbing galaxy. By examining the profiles of the metal
absorption lines arising from the absorbing galaxy in relation to its systemic
redshift, we find strong kinematical evidence for rotation. Therefore the
absorber is likely to be a disk galaxy. The inferred circular velocity for the
galaxy is >200 km/s. With a separation of ~17 kpc between the galaxy and the
quasar sightline, the implied dynamic mass for the galaxy is >1.6x10(11) solar
mass. The metallicity of the galaxy is found to be [Fe/H]=-1.4, typical of
damped Lyman-alpha galaxies at such redshifts. However, in another damped
galactic rotation is evident. In the latter case, the damped Lyman-alpha
absorber occurs near the background quasar in redshift so its properties may be
influenced by the background quasar. These represent the only two cases at
present for which the technique used here may be applied. Future applications
of the same technique to a large sample of damped Lyman-alpha galaxies may
allow us to determine if a significant population of disk galaxies already
existed only a few billion years after the Big Bang.Comment: AASTEX, 2 PS figures, accepted by ApJ, 6 pages total, replaced on
1-22-97, the only change is the enlarged figure
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