3,377 research outputs found
Subminiature micropower digital recorder
High-density digital data, collected periodically or randomly from multiplicity of sensors, are recorded by subminiature recorder. Magnetic recording head is energized with suitable pulsatile signals to reverse polarization on magnetically-sensitive tape while tape is immobilized at recording head. Prior to next recording, set tape so new area of tape is at recording head
The relationship between Hippocampal asymmetry and working memory processing in combat-related PTSD: a monozygotic twin study
BACKGROUND: PTSD is associated with reduction in hippocampal volume and abnormalities in hippocampal function. Hippocampal asymmetry has received less attention, but potentially could indicate lateralised differences in vulnerability to trauma. The P300 event-related potential component reflects the immediate processing of significant environmental stimuli and has generators in several brain regions including the hippocampus. P300 amplitude is generally reduced in people with PTSD. METHODS: Our study examined hippocampal volume asymmetry and the relationship between hippocampal asymmetry and P300 amplitude in male monozygotic twins discordant for Vietnam combat exposure. Lateralised hippocampal volume and P300 data were obtained from 70 male participants, of whom 12 had PTSD. We were able to compare (1) combat veterans with current PTSD; (2) their non-combat-exposed co-twins; (3) combat veterans without current PTSD and (4) their non-combat-exposed co-twins. RESULTS: There were no significant differences between groups in hippocampal asymmetry. There were no group differences in performance of an auditory oddball target detection task or in P300 amplitude. There was a significant positive correlation between P300 amplitude and the magnitude of hippocampal asymmetry in participants with PTSD. CONCLUSIONS: These findings suggest that greater hippocampal asymmetry in PTSD is associated with a need to allocate more attentional resources when processing significant environmental stimuli.Timothy Hall, Cherrie Galletly, C.R. Clark, Melinda Veltmeyer, Linda J. Metzger, Mark W. Gilbertson, Scott P. Orr, Roger K. Pitman and Alexander McFarlan
The development and technology transfer of software engineering technology at NASA. Johnson Space Center
The United State's big space projects of the next decades, such as Space Station and the Human Exploration Initiative, will need the development of many millions of lines of mission critical software. NASA-Johnson (JSC) is identifying and developing some of the Computer Aided Software Engineering (CASE) technology that NASA will need to build these future software systems. The goal is to improve the quality and the productivity of large software development projects. New trends are outlined in CASE technology and how the Software Technology Branch (STB) at JSC is endeavoring to provide some of these CASE solutions for NASA is described. Key software technology components include knowledge-based systems, software reusability, user interface technology, reengineering environments, management systems for the software development process, software cost models, repository technology, and open, integrated CASE environment frameworks. The paper presents the status and long-term expectations for CASE products. The STB's Reengineering Application Project (REAP), Advanced Software Development Workstation (ASDW) project, and software development cost model (COSTMODL) project are then discussed. Some of the general difficulties of technology transfer are introduced, and a process developed by STB for CASE technology insertion is described
Harm minimisation for the management of self-harm: a mixed-methods analysis of electronic health records in secondary mental healthcare
BACKGROUND:
Prevalence of self-harm in the UK was reported as 6.4% in 2014. Despite sparse evidence for effectiveness, guidelines recommend harm minimisation; a strategy in which people who self-harm are supported to do so safely.
AIMS:
To determine the prevalence, sociodemographic and clinical characteristics of those who self-harm and practise harm minimisation within a London mental health trust.
METHOD:
We included electronic health records for patients treated by South London and Maudsley NHS Trust. Using an iterative search strategy, we identified patients who practise harm minimisation, then classified the approaches using a content analysis. We compared the sociodemographic characteristics with that of a control group of patients who self-harm and do not use harm minimisation.
RESULTS:
In total 22 736 patients reported self-harm, of these 693 (3%) had records reporting the use of harm-minimisation techniques. We coded the approaches into categories: (a) ‘substitution’ (>50% of those using harm minimisation), such as using rubber bands or using ice; (b) ‘simulation’ (9%) such as using red pens; (c) ‘defer or avoid’ (7%) such as an alternative self-injury location; (d) ‘damage limitation’ (9%) such as using antiseptic techniques; the remainder were unclassifiable (24%). The majority of people using harm minimisation described it as helpful (>90%). Those practising harm minimisation were younger, female, of White ethnicity, had previous admissions and were less likely to have self-harmed with suicidal intent.
CONCLUSIONS:
A small minority of patients who self-harm report using harm minimisation, primarily substitution techniques, and the large majority find harm minimisation helpful. More research is required to determine the acceptability and effectiveness of harm-minimisation techniques and update national clinical guidelines
Solution of the Fokker-Planck equation with a logarithmic potential and mixed eigenvalue spectrum
Motivated by a problem in climate dynamics, we investigate the solution of a
Bessel-like process with negative constant drift, described by a Fokker-Planck
equation with a potential V(x) = - [b \ln(x) + a\, x], for b>0 and a<0. The
problem belongs to a family of Fokker-Planck equations with logarithmic
potentials closely related to the Bessel process, that has been extensively
studied for its applications in physics, biology and finance. The Bessel-like
process we consider can be solved by seeking solutions through an expansion
into a complete set of eigenfunctions. The associated imaginary-time
Schroedinger equation exhibits a mix of discrete and continuous eigenvalue
spectra, corresponding to the quantum Coulomb potential describing the bound
states of the hydrogen atom. We present a technique to evaluate the
normalization factor of the continuous spectrum of eigenfunctions that relies
solely upon their asymptotic behavior. We demonstrate the technique by solving
the Brownian motion problem and the Bessel process both with a negative
constant drift. We conclude with a comparison with other analytical methods and
with numerical solutions.Comment: 21 pages, 8 figure
Forces on Bins - The Effect of Random Friction
In this note we re-examine the classic Janssen theory for stresses in bins,
including a randomness in the friction coefficient. The Janssen analysis relies
on assumptions not met in practice; for this reason, we numerically solve the
PDEs expressing balance of momentum in a bin, again including randomness in
friction.Comment: 11 pages, LaTeX, with 9 figures encoded, gzippe
The Association Between Personality Disorder Traits and Suicidality Following Sudden Bereavement: A National Cross-Sectional Survey
Personality disorder is associated with increased risk of suicidal behavior. The authors aimed to investigate the association between number of personality disorder traits and suicidality risk following sudden bereavement. A secondary analysis of cross-sectional data on 3,167 young adults in the United Kingdom who had experienced sudden bereavement investigated the association between number of traits (measured using a standardized screening instrument) and postbereavement suicide attempt and suicidal ideation. Using multivariable logistic regression, the authors found a linear relationship between number of traits and suicide attempt (adjusted odds ratio [AOR] = 1.36, 95% CI [1.23, 1.49]) and suicidal ideation (AOR = 1.31, 95% CI [1.25, 1.38]) following bereavement. This represented an increase in odds by 36% and 31%, respectively, for each additional personality trait. The authors suggest that individuals with a greater number of traits suggestive of a personality disorder diagnosis are at increased risk of suicidality after a negative life event
Generalized Bayesian Record Linkage and Regression with Exact Error Propagation
Record linkage (de-duplication or entity resolution) is the process of
merging noisy databases to remove duplicate entities. While record linkage
removes duplicate entities from such databases, the downstream task is any
inferential, predictive, or post-linkage task on the linked data. One goal of
the downstream task is obtaining a larger reference data set, allowing one to
perform more accurate statistical analyses. In addition, there is inherent
record linkage uncertainty passed to the downstream task. Motivated by the
above, we propose a generalized Bayesian record linkage method and consider
multiple regression analysis as the downstream task. Records are linked via a
random partition model, which allows for a wide class to be considered. In
addition, we jointly model the record linkage and downstream task, which allows
one to account for the record linkage uncertainty exactly. Moreover, one is
able to generate a feedback propagation mechanism of the information from the
proposed Bayesian record linkage model into the downstream task. This feedback
effect is essential to eliminate potential biases that can jeopardize resulting
downstream task. We apply our methodology to multiple linear regression, and
illustrate empirically that the "feedback effect" is able to improve the
performance of record linkage.Comment: 18 pages, 5 figure
Windings of the 2D free Rouse chain
We study long time dynamical properties of a chain of harmonically bound
Brownian particles. This chain is allowed to wander everywhere in the plane. We
show that the scaling variables for the occupation times T_j, areas A_j and
winding angles \theta_j (j=1,...,n labels the particles) take the same general
form as in the usual Brownian motion. We also compute the asymptotic joint laws
P({T_j}), P({A_j}), P({\theta_j}) and discuss the correlations occuring in
those distributions.Comment: Latex, 17 pages, submitted to J. Phys.
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