15,841 research outputs found
Hearing voices network groups: experiences of eight voice hearers and the connection to group processes and recovery
Voice hearing has a diverse history but is often understood as symptomatic of a psychotic disorder. Alternatives to âtreatmentâ include peer-support âHearing Voices Network groupsâ (HVNGs) which have grown in popularity and exist alongside professional-led hearing voices groups. Few studies have investigated processes underlying change in HVNGs. Established research into therapeutic factors and personal recovery may provide frameworks elucidating change processes.
This study aimed to investigate how HVNG attendees experienced change within the group and how this change influenced their lives. A qualitative design was employed using interpretative phenomenological analysis to elucidate group processes through immersion in the perspectives of group attendees. Semi-structured interviews were conducted with eight voice hearers from two HVNGs. Interviews were recorded and transcribed verbatim. Four superordinate themes emerged: âhealing: connecting with humanityâ; âgroup as an emotional containerâ; âmaking sense of the voices and meâ; and âfreedom to be myself and growâ. Relationships, safety, exploration of voices and group ownership were key components of HVNG, but require further study. These components were consistent with therapeutic factors and known recovery processes, so these established frameworks could be used to further investigate change processes in HVNGs.
Background
Voice hearing (VH) orâauditory hallucinationsâare typically defined as symptoms of psychiatric illnesses requiring treatment. However, research has estimated that 5â28% of people have experienced VH during their lives (De Leede-Smith & Barkus, 2013) and not all of them become âillâ. Those reporting VH accompanied by distress or culturally unusual beliefs often end up in mental health services, diag- nosed with a psychotic illness and treated with medication. Whilst service user experiences of mental health services vary, many have felt failed by âa broken and demoralised system that does not deliver the quality of treatment that is needed for people to recover.â (Schizophrenia Commission, 2012, p. 4).
An alternative approach to VH emerged from the Hearing Voices Movement (HVM) in Holland. Its foundation stemmed from a key study demonstrating that 33% of voice hearers coped with VH experi- ences (Romme & Escher, 1989). This endeavour was driven by social needs and political/emancipatory aims (Romme, Honig, Noorthoorn, & Escher, 1992): empowering voice hearers to explore their experi- ences (Coleman & Smith, 1997); disseminating coping strategies; promoting alternatives to dominant.
CONTACT Tom Payne [email protected] Š 2017 Informa UK Limited, trading as Taylor & Francis Grou
Liberating exomoons in white dwarf planetary systems
Previous studies indicate that more than a quarter of all white dwarf (WD)
atmospheres are polluted by remnant planetary material, with some WDs being
observed to accrete the mass of Pluto in 10^6 years. The short sinking
timescale for the pollutants indicate that the material must be frequently
replenished. Moons may contribute decisively to this pollution process if they
are liberated from their parent planets during the post-main-sequence evolution
of the planetary systems. Here, we demonstrate that gravitational scattering
events among planets in WD systems easily triggers moon ejection. Repeated
close encounters within tenths of a planetary Hill radii are highly destructive
to even the most massive, close-in moons. Consequently, scattering increases
both the frequency of perturbing agents in WD systems, as well as the available
mass of polluting material in those systems, thereby enhancing opportunities
for collision and fragmentation and providing more dynamical pathways for
smaller bodies to reach the WD. Moreover, during intense scattering, planets
themselves have pericenters with respect to the WD of only a fraction of an AU,
causing extreme Hill-sphere contraction, and the liberation of moons into
WD-grazing orbits. Many of our results are directly applicable to exomoons
orbiting planets around main sequence stars.Comment: Published (MNRAS): First published online January 19, 201
The Fate of Exomoons in White Dwarf Planetary Systems
Roughly 1000 white dwarfs are known to be polluted with planetary material,
and the progenitors of this material are typically assumed to be asteroids. The
dynamical architectures which perturb asteroids into white dwarfs are still
unknown, but may be crucially dependent on moons liberated from parent planets
during post-main-sequence gravitational scattering. Here, we trace the fate of
these exomoons, and show that they more easily achieve deep radial incursions
towards the white dwarf than do scattered planets. Consequently, moons are
likely to play a significant role in white dwarf pollution, and in some cases
may be the progenitors of the pollution itself.Comment: 9 pages, 5 figures, accepted for publication in MNRA
Testing hypotheses of the cause of peripheral thinning of the Greenland Ice Sheet: is land-terminating ice thinning at anomalously high rates?
Recent observations have shown that the periphery of the Greenland ice sheet (GrIS) is thinning rapidly and that this thinning is greatest around marine-terminating outlet glaciers. Several theories have been proposed which provide a link between climate and ice thinning. We present surface elevation change (<i>dh/dt</i>) data from NASA's Program for Arctic Regional Climate Assessment (PARCA) laser altimetry surveys for fourteen and eleven of the largest outlet glaciers in Southern Greenland from 1993 to 1998 and 1998 to 2006 respectively to test the applicability of these theories to the GrIS. <br><br> Initially, outlet glacier <i>dh/dt</i> data are compared with data from concurrent surveys over inland ice (slow flowing ice that is not obviously draining into an outlet glacier) to confirm the effect of ice flow on surface thinning rates. Land-terminating and marine-terminating outlet glacier <i>dh/dt</i> data are then compared from 1993 to 1998 and from 1998 to 2006. Finally, ablation anomalies (the difference between the "normal" ablation rate from 1970 to 2000 and the ablation rate in the time period of interest) calculated with a positive degree day model are compared to both marine-terminating and land-terminating outlet glacier <i>dh/dt</i> data. <br><br> Our results support earlier conclusions that certain marine-terminating outlet glaciers have thinned much more than land-terminating outlet glaciers during both time periods. Furthermore we show that these differences are not limited to the largest, fastest-flowing outlet glaciers â almost all marine-terminating outlet glaciers are thinning more than land-terminating outlet glaciers. There was a four fold increase in mean marine-terminating outlet glacier thinning rates below 1000 m elevation between the periods 1993 to 1998 and 1998 to 2006, while thinning rates of land-terminating outlet glaciers remained statistically unchanged. This suggests that a change in a controlling mechanism specific to the thinning rates of marine-terminating outlet glaciers occurred in the late 1990s and that this change did not affect thinning rates of land-terminating outlet glaciers. <br><br> Thinning rates of land-terminating outlet glaciers are statistically the same as ablation anomalies, while thinning rates of marine-terminating outlet glaciers are not. Thinning of land-terminating outlet glaciers therefore seems to be a response to changes in local mass balance (principally increases in air temperature) while thinning of marine-terminating outlet glaciers is principally controlled by ice dynamics. The mechanism by which this dynamic thinning occurs is still not clear although its association with marine-terminating outlet glaciers suggests perturbations at marine termini (calving) as the likely cause
Posterior Distribution of Nondifferentiable Functions
This paper examines the asymptotic behavior of the posterior distribution of a possibly nondifferentiable function g(theta), where theta is a finite dimensional parameter. The main assumption is that the distribution of the maximum likelihood estimator theta_n, its bootstrap approximation, and the Bayesian posterior for theta all agree asymptotically. It is shown that whenever g is Lipschitz, though not necessarily differentiable, the posterior distribution of g(theta) and the bootstrap distribution of g(theta_n) coincide asymptotically. One implication is that Bayesians can interpret bootstrap inference for g(theta) as approximately valid posterior inference in a large sample. Another implicationâbuilt on known results about bootstrap inconsistencyâis that the posterior distribution of g(theta) does not coincide with the asymptotic distribution of g(theta_n) at points of nondifferentiability. Consequently, frequentists cannot presume that credible sets for a nondifferentiable parameter g(theta) can be interpreted as approximately valid confidence sets (even when this relation holds true for theta)
Newly-Discovered Planets Orbiting HD~5319, HD~11506, HD~75784 and HD~10442 from the N2K Consortium
Initially designed to discover short-period planets, the N2K campaign has
since evolved to discover new worlds at large separations from their host
stars. Detecting such worlds will help determine the giant planet occurrence at
semi-major axes beyond the ice line, where gas giants are thought to mostly
form. Here we report four newly-discovered gas giant planets (with minimum
masses ranging from 0.4 to 2.1 MJup) orbiting stars monitored as part of the
N2K program. Two of these planets orbit stars already known to host planets: HD
5319 and HD 11506. The remaining discoveries reside in previously-unknown
planetary systems: HD 10442 and HD 75784. The refined orbital period of the
inner planet orbiting HD 5319 is 641 days. The newly-discovered outer planet
orbits in 886 days. The large masses combined with the proximity to a 4:3 mean
motion resonance make this system a challenge to explain with current formation
and migration theories. HD 11506 has one confirmed planet, and here we confirm
a second. The outer planet has an orbital period of 1627.5 days, and the
newly-discovered inner planet orbits in 223.6 days. A planet has also been
discovered orbiting HD 75784 with an orbital period of 341.7 days. There is
evidence for a longer period signal; however, several more years of
observations are needed to put tight constraints on the Keplerian parameters
for the outer planet. Lastly, an additional planet has been detected orbiting
HD 10442 with a period of 1043 days.Comment: Accepted for publication in Ap
Posterior distribution of nondifferentiable functions
This paper examines the asymptotic behavior of the posterior distribution of a possibly nondifferentiable function g(θ), where θ is a finite-dimensional parameter of either a parametric or semiparametric model. The main assumption is that the distribution of a suitable estimator θ^n, its bootstrap approximation, and the Bayesian posterior for θ all agree asymptotically. It is shown that whenever g is locally Lipschitz, though not necessarily differentiable, the posterior distribution of g(θ) and the bootstrap distribution of g(θ^n) coincide asymptotically. One implication is that Bayesians can interpret bootstrap inference for g(θ) as approximately valid posterior inference in a large sample. Another implicationâbuilt on known results about bootstrap inconsistencyâis that credible intervals for a nondifferentiable parameter g(θ) cannot be presumed to be approximately valid confidence intervals (even when this relation holds true for θ)
General implementation of all possible positive-operator-value measurements of single photon polarization states
Positive Operator Value Measures (POVMs) are the most general class of
quantum measurements. We propose a setup in which all possible POVMs of a
single photon polarization state (corresponding to all possible sets of
two-dimensional Kraus operators) can be implemented easily using linear optics
elements. This method makes it possible to experimentally realize any
projective orthogonal, projective non-orthogonal or non-projective sets of any
number of POVM operators. Furthermore our implementation only requires vacuum
ancillas, and is deterministic rather than probabilistic. Thus it realizes
every POVM with the correct set of output states. We give the settings required
to implement two different well-known non-orthogonal projective POVMs.Comment: 5 pages, newer version with minor addition
Radio Recombination Lines at Decametre Wavelengths: Prospects for the Future
This paper considers the suitability of a number of emerging and future
instruments for the study of radio recombination lines (RRLs) at frequencies
below 200 MHz. These lines arise only in low-density regions of the ionized
interstellar medium, and they may represent a frequency-dependent foreground
for next-generation experiments trying to detect H I signals from the Epoch of
Reionization and Dark Ages ("21-cm cosmology"). We summarize existing
decametre-wavelength observations of RRLs, which have detected only carbon
RRLs. We then show that, for an interferometric array, the primary instrumental
factor limiting detection and study of the RRLs is the areal filling factor of
the array. We consider the Long Wavelength Array (LWA-1), the LOw Frequency
ARray (LOFAR), the low-frequency component of the Square Kilometre Array
(SKA-lo), and a future Lunar Radio Array (LRA), all of which will operate at
decametre wavelengths. These arrays offer digital signal processing, which
should produce more stable and better defined spectral bandpasses; larger
frequency tuning ranges; and better angular resolution than that of the
previous generation of instruments that have been used in the past for RRL
observations. Detecting Galactic carbon RRLs, with optical depths at the level
of 10^-3, appears feasible for all of these arrays, with integration times of
no more than 100 hr. The SKA-lo and LRA, and the LWA-1 and LOFAR at the lowest
frequencies, should have a high enough filling factor to detect lines with much
lower optical depths, of order 10^-4 in a few hundred hours. The amount of
RRL-hosting gas present in the Galaxy at the high Galactic latitudes likely to
be targeted in 21-cm cosmology studies is currently unknown. If present,
however, the spectral fluctuations from RRLs could be comparable to or exceed
the anticipated H I signals.Comment: 9 pages; Astron. & Astrophys., in pres
Validation of the inverted adsorption structure for free-base tetraphenyl porphyrin on Cu(111)
Utilising normal incidence X-ray standing waves we rigourously scrutinise the âinverted modelâ as the adsorption structure of free-base tetraphenyl porphyrin on Cu(111). We demonstrate that the iminic N atoms are anchored at near-bridge adsorption sites on the surface displaced laterally by 1.1 Âą 0.2 Ă
in excellent agreement with previously published calculations
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