2,288 research outputs found
Psychologists Collaborating With Clergy
If a patient adheres to religious values and practices, should the treating psychologist get input from a clergyperson? How frequent is clergy-psychologist collaboration? What obstacles impede such collaboration? An exploratory survey questionnaire was sent to 200 clergy, 200 psychologists interested in religious issues, and 200 psychologists selected without regard to religious interests or values. Four themes were assessed: types of collaborative activities, frequency of collaboration, obstacles to collaboration, and ways to enhance collaboration. Strategies for promoting clergy-psychologist collaboration include challenging unidirectional referral assumptions, building trust through proximity and familiarity, and considering the importance of shared values and beliefs
Momentum-space engineering of gaseous Bose-Einstein condensates
We show how the momentum distribution of gaseous Bose--Einstein condensates
can be shaped by applying a sequence of standing-wave laser pulses. We present
a theory, whose validity for was demonstrated in an earlier experiment [L.\
Deng, et al., \prl {\bf 83}, 5407 (1999)], of the effect of a two-pulse
sequence on the condensate wavefunction in momentum space. We generalize the
previous result to the case of pulses of arbitrary intensity separated by
arbitrary intervals and show how these parameters can be engineered to produce
a desired final momentum distribution. We find that several momentum
distributions, important in atom-interferometry applications, can be engineered
with high fidelity with two or three pulses.Comment: 13 pages, 4 figure
Probing the circulation of ring-shaped Bose-Einstein condensates
This paper reports the results of a theoretical and experimental study of how
the initial circulation of ring-shaped Bose-Einstein condensates (BECs) can be
probed by time-of-flight (TOF) images. We have studied theoretically the
dynamics of a BEC after release from a toroidal trap potential by solving the
3D Gross-Pitaevskii (GP) equation. The trap and condensate characteristics
matched those of a recent experiment. The circulation, experimentally imparted
to the condensate by stirring, was simulated theoretically by imprinting a
linear azimuthal phase on the initial condensate wave function. The theoretical
TOF images were in good agreement with the experimental data. We find that upon
release the dynamics of the ring--shaped condensate proceeds in two distinct
phases. First, the condensate expands rapidly inward, filling in the initial
hole until it reaches a minimum radius that depends on the initial circulation.
In the second phase, the density at the inner radius increases to a maximum
after which the hole radius begins slowly to expand. During this second phase a
series of concentric rings appears due to the interference of ingoing and
outgoing matter waves from the inner radius. The results of the GP equation
predict that the hole area is a quadratic function of the initial circulation
when the condensate is released directly from the trap in which it was stirred
and is a linear function of the circulation if the trap is relaxed before
release. These scalings matched the data. Thus, hole size after TOF can be used
as a reliable probe of initial condensate circulation. This connection between
circulation and hole size after TOF will facilitate future studies of
atomtronic systems that are implemented in ultracold quantum gases.Comment: 9 pages, 9 figure
Air ambulance outcome measures using Institutes of Medicine and Donabedian quality frameworks: protocol for a systematic scoping review
Background: Dedicated air ambulance services provide a vital link for critically ill and injured patients to higherlevels of care. The recent developments of pre-hospital and retrieval medicine create an opportunity for airambulance providers and policy-makers to utilize a dashboard of quality performance measures to assess serviceperformance. The objective of this scoping systematic review will be to identify and evaluate the range of airambulance outcome measures reported in the literature and help to construct a quality dashboard based on ahealthcare quality framework.
Methods: We will search PubMed, MEDLINE, CINAHL, Scopus, and Cochrane Database of Systematic Reviews (fromJanuary 2001 onwards). Complementary searches will be conducted in selected relevant journals. We will includesystematic reviews and observational studies (cohort, cross-sectional, interrupted time series) in critically ill orinjured patients published in English and focusing on air ambulance delivery and quality measures. Two reviewerswill independently screen all citations, full-text articles, and abstract data. The study methodological quality (or bias)will be appraised using appropriate tools. Analysis of the characteristics associated with outcome measure will bemapped and described according to the proposed healthcare quality framework.
Discussion: This review will contribute to the development of an air ambulance quality dashboard designed tocombine multiple quality frameworks. Our findings will provide a basis for helping decision-making in healthplanning and policy
Insulator-to-Metal Transition in Selenium-Hyperdoped Silicon: Observation and Origin
Hyperdoping has emerged as a promising method for designing semiconductors
with unique optical and electronic properties, although such properties
currently lack a clear microscopic explanation. Combining computational and
experimental evidence, we probe the origin of sub-band gap optical absorption
and metallicity in Se-hyperdoped Si. We show that sub-band gap absorption
arises from direct defect-to-conduction band transitions rather than free
carrier absorption. Density functional theory predicts the Se-induced
insulator-to-metal transition arises from merging of defect and conduction
bands, at a concentration in excellent agreement with experiment. Quantum Monte
Carlo calculations confirm the critical concentration, demonstrate that
correlation is important to describing the transition accurately, and suggest
that it is a classic impurity-driven Mott transition.Comment: 5 pages, 3 figures (PRL formatted
A replication of the 5–7day dream-lag effect with comparison of dreams to future events as control for baseline matching
The dream-lag effect refers to there being, after the frequent incorporation of memory elements from the previous day into dreams (the day-residue), a lower incorporation of memory elements from 2 to 4 days before the dream, but then an increased incorporation of memory elements from 5 to 7 days before the dream. Participants kept a daily diary and a dream diary for 14 days and then rated the level of matching between every dream report and every daily diary record. A significant dream-lag effect for the 5–7 day period, compared to baseline and compared to the 2–4 day period, was found. This may indicate a memory processing function for sleep, which the dream content may reflect. The paper has significant theoretical implications for the time-course of consolidating autobiographical memory
Using modified intention-to-treat as a principal stratum estimator for failure to initiate treatment
Background: A common intercurrent event affecting many trials is when some
participants do not begin their assigned treatment. Many trials use a modified
intention-to-treat (mITT) approach, whereby participants who do not initiate
treatment are excluded from the analysis. However, it is not clear the estimand
being targeted by such an approach or the assumptions necessary for it to be
unbiased.
Methods: We demonstrate that a mITT analysis which excludes participants who
do not begin treatment is estimating a principal stratum estimand (i.e. the
treatment effect in the subpopulation of participants who would begin
treatment, regardless of which arm they were assigned to). The mITT estimator
is unbiased for the principal stratum estimand under the assumption that the
intercurrent event is not affected by the assigned treatment arm, that is,
participants who initiate treatment in one arm would also do so in the other
arm.
Results: We identify two key criteria in determining whether the mITT
estimator is likely to be unbiased: first, we must be able to measure the
participants in each treatment arm who experience the intercurrent event, and
second, the assumption that treatment allocation will not affect whether the
participant begins treatment must be reasonable. Most double-blind trials will
satisfy these criteria, and we provide an example of an open-label trial where
these criteria are likely to be satisfied as well.
Conclusions: A modified intention-to-treat analysis which excludes
participants who do not begin treatment can be an unbiased estimator for the
principal stratum estimand. Our framework can help identify when the
assumptions for unbiasedness are likely to hold, and thus whether modified
intention-to-treat is appropriate or not.Comment: Changes to Introduction and Abstract, minor changes to Method
A simple principal stratum estimator for failure to initiate treatment
A common intercurrent event affecting many trials is when some participants
do not begin their assigned treatment. For example, in a trial comparing two
different methods for fluid delivery during surgery, some participants may have
their surgery cancelled. Similarly, in a double-blind drug trial, some
participants may not receive any dose of study medication. The commonly used
intention-to-treat analysis preserves the randomisation structure, thus
protecting against biases from post-randomisation exclusions. However, it
estimates a treatment policy effect (i.e. addresses the question "what is the
effect of the intervention, regardless of whether the participant actually
begins treatment?"), which may not be the most clinically relevant estimand. A
principal stratum approach, estimating the treatment effect in the
subpopulation of participants who would initiate treatment (regardless of
treatment arm), may be a more clinically relevant estimand for many trials. We
show that a simple principal stratum estimator based on a "modified
intention-to-treat" population, where participants who experience the
intercurrent event are excluded, is unbiased for the principal stratum estimand
under certain assumptions that are likely to be plausible in many trials,
namely that participants who initiate the intervention under one treatment
condition would also do so under the other treatment condition. We provide
several examples of trials where this assumption is plausible, and several
instances where it is not. We conclude that this simple principal stratum
estimator can be a useful strategy for handling failure to initiate treatment
Using modified intention-to-treat as a principal stratum estimator for failure to initiate treatment
BACKGROUND: A common intercurrent event affecting many trials is when some participants do not begin their assigned treatment. For example, in a double-blind drug trial, some participants may not receive any dose of study medication. Many trials use a 'modified intention-to-treat' approach, whereby participants who do not initiate treatment are excluded from the analysis. However, it is not clear (a) the estimand being targeted by such an approach and (b) the assumptions necessary for such an approach to be unbiased. METHODS: Using potential outcome notation, we demonstrate that a modified intention-to-treat analysis which excludes participants who do not begin treatment is estimating a principal stratum estimand (i.e. the treatment effect in the subpopulation of participants who would begin treatment, regardless of which arm they were assigned to). The modified intention-to-treat estimator is unbiased for the principal stratum estimand under the assumption that the intercurrent event is not affected by the assigned treatment arm, that is, participants who initiate treatment in one arm would also do so in the other arm (i.e. if someone began the intervention, they would also have begun the control, and vice versa). RESULTS: We identify two key criteria in determining whether the modified intention-to-treat estimator is likely to be unbiased: first, we must be able to measure the participants in each treatment arm who experience the intercurrent event, and second, the assumption that treatment allocation will not affect whether the participant begins treatment must be reasonable. Most double-blind trials will satisfy these criteria, as the decision to start treatment cannot be influenced by the allocation, and we provide an example of an open-label trial where these criteria are likely to be satisfied as well, implying that a modified intention-to-treat analysis which excludes participants who do not begin treatment is an unbiased estimator for the principal stratum effect in these settings. We also give two examples where these criteria will not be satisfied (one comparing an active intervention vs usual care, where we cannot identify which usual care participants would have initiated the active intervention, and another comparing two active interventions in an unblinded manner, where knowledge of the assigned treatment arm may affect the participant's choice to begin or not), implying that a modified intention-to-treat estimator will be biased in these settings. CONCLUSION: A modified intention-to-treat analysis which excludes participants who do not begin treatment can be an unbiased estimator for the principal stratum estimand. Our framework can help identify when the assumptions for unbiasedness are likely to hold, and thus whether modified intention-to-treat is appropriate or not
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