5,892 research outputs found
Mutual help groups for mental health problems: A review of effectiveness studies
This paper reviews empirical studies on whether participating in mutual help groups for people with mental health problems leads to improved psychological and social functioning. To be included, studies had to satisfy four sets of criteria, covering: (1) characteristics of the group, (2) target problems, (3) outcome measures, and (4) research design. The 12 studies meeting these criteria provide limited but promising evidence that mutual help groups benefit people with three types of problems: chronic mental illness, depression/anxiety, and bereavement. Seven studies reported positive changes for those attending support groups. The strongest findings come from two randomized trials showing that the outcomes of mutual help groups were equivalent to those of substantially more costly professional interventions. Five of the 12 studies found no differences in mental health outcomes between mutual help group members and non-members; no studies showed evidence of negative effects. There was no indication that mutual help groups were differentially effective for certain types of problems. The studies varied in terms of design quality and reporting of results. More high-quality outcome research is needed to evaluate the effectiveness of mutual help groups across the spectrum of mental health problems
Individualism-collectivism and interpersonal memory guidance of attention
Recently it has been shown that the allocation of attention by a participant in a visual search task can be affected by memory items that have to be maintained by a co-actor, when similar tasks are jointly engaged by dyads (He, Lever, & Humphreys, 2011). In the present study we examined the contribution of individualism-collectivism to this ‘interpersonal memory guidance’ effect. Actors performed visual search while a preview image was either held by the critical participant, held by a co-actor or was irrelevant to either participant. Attention during search was attracted to stimuli that matched the contents of the co-actor’s memory. This interpersonal effect correlated with the collectivism scores, and was enhanced by priming with a collectivistic scenario. The dimensions of individualism, however, did not contribute to performance. These data suggest that collectivism, but not individualism, modulates interpersonal influences on memory and attention in joint action
Guidelines for composite materials research related to general aviation aircraft
Guidelines for research on composite materials directed toward the improvement of all aspects of their applicability for general aviation aircraft were developed from extensive studies of their performance, manufacturability, and cost effectiveness. Specific areas for research and for manufacturing development were identified and evaluated. Inputs developed from visits to manufacturers were used in part to guide these evaluations, particularly in the area of cost effectiveness. Throughout the emphasis was to direct the research toward the requirements of general aviation aircraft, for which relatively low load intensities are encountered, economy of production is a prime requirement, and yet performance still commands a premium. A number of implications regarding further directions for developments in composites to meet these requirements also emerged from the studies. Chief among these is the need for an integrated (computer program) aerodynamic/structures approach to aircraft design
Onsite analysis of data from the Dynamics Explorer (DE) spacecraft
The tasks performed by ARC Professional Services Group, Inc. fell into five parts: (1) dynamics explorer (DE) data analysis and modeling; (2) DE project support; (3) chemical release observations support; (4) VLF emissions and plasma instability studies; and (5) modeling of planetary radio emissions. Some recommendations for future considerations are also addressed
Indecomposable finite-dimensional representations of a class of Lie algebras and Lie superalgebras
In the article at hand, we sketch how, by utilizing nilpotency to its fullest
extent (Engel, Super Engel) while using methods from the theory of universal
enveloping algebras, a complete description of the indecomposable
representations may be reached. In practice, the combinatorics is still
formidable, though.
It turns out that the method applies to both a class of ordinary Lie algebras
and to a similar class of Lie superalgebras.
Besides some examples, due to the level of complexity we will only describe a
few precise results. One of these is a complete classification of which ideals
can occur in the enveloping algebra of the translation subgroup of the
Poincar\'e group. Equivalently, this determines all indecomposable
representations with a single, 1-dimensional source. Another result is the
construction of an infinite-dimensional family of inequivalent representations
already in dimension 12. This is much lower than the 24-dimensional
representations which were thought to be the lowest possible. The complexity
increases considerably, though yet in a manageable fashion, in the
supersymmetric setting. Besides a few examples, only a subclass of ideals of
the enveloping algebra of the super Poincar\'e algebra will be determined in
the present article.Comment: LaTeX 14 page
GNSS Signal Authentication via Power and Distortion Monitoring
We propose a simple low-cost technique that enables
civil Global Positioning System (GPS) receivers and other civil
global navigation satellite system (GNSS) receivers to reliably
detect carry-off spoofing and jamming. The technique, which
we call the Power-Distortion detector, classifies received signals
as interference-free, multipath-afflicted, spoofed, or jammed
according to observations of received power and correlatio
n
function distortion. It does not depend on external hardware or
a network connection and can be readily implemented on many
receivers via a firmware update. Crucially, the detector can with
high probability distinguish low-power spoofing from ordinary
multipath. In testing against over 25 high-quality empirical data
sets yielding over 900,000 separate detection tests, the detector
correctly alarms on all malicious spoofing or jamming attack
s
while maintaining a
<0.5% single-channel false alarm rate.Aerospace Engineering and Engineering Mechanic
A Method for Evaluating the Cumulative Impact of Ground-Based Logging Systems on Soils
A method for determining the Effective Ground Pressure (EGP) of tracked or wheeled logging machines that can be directly and unambiguously related to their impact on soils is described. When several machines operate together in a logging system, the methodology allows their individual EGP's to be combined to derive a System Effective Ground Pressure (SEGP), which measures the impact of the system as a whole. The methodology has been applied to determine the relative impact of logging systems and influence the choice of machine running gear. Given also the temporal variability in the bearing capacity of soils, it has also been applied to forecasting the minimum level of disruption to operations on flat ground arising from limitations placed on soil disturbance. These applications have led to increased efficiency of operations through a reduction in wood stockpiling during wet weather. The method is sufficiently simplistic at the core, that contractors with the aid of appropriate charts have evaluated the relative impact of machines and systems on soils themselves
The transferability of the low-cost model to long-haul airline operations
Since their emergence in the US in the mid 1970's there has been
significant growth in the low-cost airline sector but with a few notable
exceptions low-cost airlines have operated on short-haul routes. This
paper examines the extent to which the low-cost model is, or could be,
applicable to long-haul operations and whether the recent emergence of
long-haul low-cost carriers is a sustainable phenomenon. The authors
explore the extent to which elements of the so-called low-cost model
might be transferable to long-haul operations. The paper seeks to quantify
the potential cost differentials that might be achievable on a long-haul service. The paper also speculates as to the development and sustainability of the low-cost long-haul operations
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