11,291 research outputs found
Implementation of the Crisis Resolution Team model in adult mental health settings: a systematic review.
Crisis Resolution Teams (CRTs) aim to offer an alternative to hospital admission during mental health crises, providing rapid assessment, home treatment, and facilitation of early discharge from hospital. CRTs were implemented nationally in England following the NHS Plan of 2000. Single centre studies suggest CRTs can reduce hospital admissions and increase service users' satisfaction: however, there is also evidence that model implementation and outcomes vary considerably. Evidence on crucial characteristics of effective CRTs is needed to allow team functioning to be optimised. This review aims to establish what evidence, if any, is available regarding the characteristics of effective and acceptable CRTs
Attosecond pulse shaping around a Cooper minimum
High harmonic generation (HHG) is used to measure the spectral phase of the
recombination dipole matrix element (RDM) in argon over a broad frequency range
that includes the 3p Cooper minimum (CM). The measured RDM phase agrees well
with predictions based on the scattering phases and amplitudes of the
interfering s- and d-channel contributions to the complementary photoionization
process. The reconstructed attosecond bursts that underlie the HHG process show
that the derivative of the RDM spectral phase, the group delay, does not have a
straight-forward interpretation as an emission time, in contrast to the usual
attochirp group delay. Instead, the rapid RDM phase variation caused by the CM
reshapes the attosecond bursts.Comment: 5 pages, 5 figure
Yang-Mills gravity in biconformal space
We write a gravity theory with Yang-Mills type action using the biconformal
gauging of the conformal group. We show that the resulting biconformal
Yang-Mills gravity theories describe 4-dim, scale-invariant general relativity
in the case of slowly changing fields. In addition, we systematically extend
arbitrary 4-dim Yang-Mills theories to biconformal space, providing a new arena
for studying flat space Yang-Mills theories. By applying the biconformal
extension to a 4-dim pure Yang-Mills theory with conformal symmetry, we
establish a 1-1, onto mapping between a set of gravitational gauge theories and
4-dim, flat space gauge theories.Comment: 27 pages; paper emphasis shifted to focus on gravity; references
adde
The Convective Urca Process with Implicit Two-Dimensional Hydrodynamics
Consideration of the role of the convective flux in the thermodymics of the
convective Urca neutrino loss process in degenerate, convective, quasi-static,
carbon-burning cores shows that the convective Urca process slows down the
convective current around the Urca-shell, but, unlike the "thermal" Urca
process, does not reduce the entropy or temperature for a given convective
volume. Here we demonstrate these effects with two-dimensional numerical
hydrodynamical calculations. These two-dimensional implicit hydrodynamics
calculations invoke an artificial speeding up of the nuclear and weak rates.
They should thus be regarded as indicative, but still qualitative. We find
that, compared to a case with no Urca-active nuclei, the case with Urca effects
leads to a higher entropy in the convective core because the energy released by
nuclear burning is confined to a smaller volume by the effective boundary at
the Urca shell. All else being equal, this will tend to accelerate the
progression to dynamical runaway. We discuss the open issues regarding the
impact of the convective Urca process on the evolution to the "smoldering
phase" and then to dynamical runaway.Comment: 22 pages, 11 figures, accepted for publication in the Astrophysical
Journa
Phase field modeling of electrochemistry II: Kinetics
The kinetic behavior of a phase field model of electrochemistry is explored
for advancing (electrodeposition) and receding (electrodissolution) conditions
in one dimension. We described the equilibrium behavior of this model in [J. E.
Guyer, W. J. Boettinger, J.A. Warren, and G. B. McFadden, ``Phase field
modeling of electrochemistry I: Equilibrium'', cond-mat/0308173]. We examine
the relationship between the parameters of the phase field method and the more
typical parameters of electrochemistry. We demonstrate ohmic conduction in the
electrode and ionic conduction in the electrolyte. We find that, despite making
simple, linear dynamic postulates, we obtain the nonlinear relationship between
current and overpotential predicted by the classical ``Butler-Volmer'' equation
and observed in electrochemical experiments. The charge distribution in the
interfacial double layer changes with the passage of current and, at
sufficiently high currents, we find that the diffusion limited deposition of a
more noble cation leads to alloy deposition with less noble species.Comment: v3: To be published in Phys. Rev. E v2: Attempt to work around
turnpage bug. Replaced color Fig. 4a with grayscale 13 pages, 7 figures in 10
files, REVTeX 4, SIunits.sty, follows cond-mat/030817
Characterizing Teaching Assistants’ Knowledge and Beliefs Following Professional Development Activities within an Inquiry-Based General Chemistry Context
The purpose of this investigation was to explore changes in undergraduate and graduate teaching assistants’ (TAs’) content knowledge and beliefs about teaching within the context of an inquiry-based laboratory course. TAs received professional development (PD), which was informed by the TA training literature base and was designed for TAs implementing a guided inquiry approach to general chemistry laboratory instruction. TAs engaged in ∼20 h of presemester PD and ∼30 h of weekly follow-up PD during the semester. The study utilized a multiple-methods approach within a social constructivist framework to assess changes in the TAs. Participants included eight graduate TAs and five undergraduate TAs. Data collection included TA pre-PD, post-PD, and semester-end surveys and two interviews of a subset of participants. The quantitative data were analyzed using descriptive and nonparametric statistics, and the qualitative data were analyzed using systematic data analysis. The results indicate that TAs’ content knowledge significantly improved following the PD (mean = 80.22, standard deviation = 11.80) (Z = −2.346, p = 0.019) and was maintained over the semester. Following PD, the TAs shifted their beliefs to be more aligned with inquiry-based instruction. The results of this investigation suggest that TA previous experience and teaching students in an inquiry-based lab may influence TAs’ beliefs. Future research will focus on examining the impact of TAs on student outcomes within a guided inquiry approach to general chemistry laboratory instruction
Gravity and Nonequilibrium Thermodynamics of Classical Matter
Renewed interest in deriving gravity (more precisely, the Einstein equations)
from thermodynamics considerations [1, 2] is stirred up by a recent proposal
that 'gravity is an entropic force' [3] (see also [4]). Even though I find the
arguments justifying such a claim in this latest proposal rather ad hoc and
simplistic compared to the original one I would unreservedly support the call
to explore deeper the relation between gravity and thermodynamics, this having
the same spirit as my long-held view that general relativity is the
hydrodynamic limit [5, 6] of some underlying theories for the microscopic
structure of spacetime - all these proposals, together with that of [7, 8],
attest to the emergent nature of gravity [9]. In this first paper of two we set
the modest goal of studying the nonequilibrium thermodynamics of classical
matter only, bringing afore some interesting prior results, without invoking
any quantum considerations such as Bekenstein-Hawking entropy, holography or
Unruh effect. This is for the sake of understanding the nonequilibrium nature
of classical gravity which is at the root of many salient features of black
hole physics. One important property of gravitational systems, from
self-gravitating gas to black holes, is their negative heat capacity, which is
the source of many out-of-the ordinary dynamical and thermodynamic features
such as the non-existence in isolated systems of thermodynamically stable
configurations, which actually provides the condition for gravitational
stability. A related property is that, being systems with long range
interaction, they are nonextensive and relax extremely slowly towards
equilibrium. Here we explore how much of the known features of black hole
thermodynamics can be derived from this classical nonequilibrium perspective. A
sequel paper will address gravity and nonequilibrium thermodynamics of quantum
fields [10].Comment: 25 pages essay. Invited Talk at Mariofest, March 2010, Rosario,
Argentina. Festschrift to appear as an issue of IJMP
Two-photon decays of hadronic molecules
In many calculations of the two--photon decay of hadronic molecules, the
decay matrix element is estimated using the wave function at the origin
prescription, in analogy to the two-photon decay of parapositronium. We
question the applicability of this procedure to the two-photon decay of
hadronic molecules for it introduces an uncontrolled model dependence into the
calculation. As an alternative approach, we propose an explicit evaluation of
the hadron loop. For shallow bound states, this can be done as an expansion in
powers of the range of the molecule binding force. In the leading order one
gets the well-known point-like limit answer. We estimate, in a self-consistent
and gauge invariant way, the leading range corrections for the two-photon decay
width of weakly bound hadronic molecules emerging from kaon loops. We find them
to be small. The role of possible short-ranged operators and of the width of
the scalars remains to be investigated.Comment: LaTeX2e, 26 pages, new figure and additional appendix added, version
to appear in Phys.Rev.
Investigating the role of a district science coordinator
This study explored the professional responsibilities of district science coordinators, their professional development (PD) experiences, the relationship between their role, responsibilities, district context, and background, and barriers encountered in their work. A national sample (n = 122) of self‐identified science coordinators completed a Science Coordinator Role Survey. Participants’ responses were analyzed using descriptive and correlational statistics. Following analysis of survey data, 16 participants (13.1%) were purposefully selected for semi‐structured follow‐up interviews. Results indicated the majority of respondents identified themselves as Caucasian, female, and had served in their position for less than 10 years. The typical science coordinator held a degree in a science content area and was a former science teacher. Respondents without science degrees tended to hold positions at small, remote, or rural school districts with responsibilities in multiple content areas. Participants also reported barriers of not having enough PD opportunities, lack of time, lack of emphasis on science instruction, and a lack of power to enforce policies within a district. Results characterize the professional responsibilities of coordinators, provide insight into the role of a science coordinator, and into how to create targeted PD for coordinators
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