30,212 research outputs found
The age related prevalence of aggression and self-injury in persons with an intellectual disability: A review
The aim of this study was to analyse statistically published data regarding the age related prevalence of aggression and self-injury in persons with intellectual disability. Studies including prevalence data for aggression and/or self-injury broken down by age band were identified and relative risk analyses conducted to generate indices of age related change. Despite conflicting results, the analysis conducted on included studies considered to be the most methodologically robust indicated that the relative risk of self-injury, and to a lesser extent aggression, increased with age until mid-adulthood, with some indication of a curvilinear relationship for self-injury. These conclusions have implications for the understanding of the development of different forms of challenging behavior and the importance of early intervention strategies
Self-injurious behaviour in individuals with autism spectrum disorder
Background: Autism spectrum disorder (ASD) has been identified as a risk marker for self-injurious behaviour. In this study we aimed to describe the prevalence, topography and correlates of self-injury in individuals with ASD in contrast to individuals with Fragile X and Down syndromes and examine person characteristics associated with self-injury across and within these groups.\ud
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Method: Carers of individuals with ASD (N=149; mean age=9.98, SD=4.86), Fragile X syndrome (N=123; mean age=15.32, SD=8.74) and Down syndrome (N=49; mean age=15.84, SD=12.59) completed questionnaires relating to the presence and topography of self-injury Information was also gathered regarding demographic characteristics, affect, autistic behaviour, hyperactivity, impulsivity and repetitive behaviour.\ud
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Results: Self-injurious behaviour was displayed by 50% of the ASD sample; a significantly higher prevalence than in the Down syndrome group (18.4%) but broadly similar to the prevalence in Fragile X syndrome (54.5%). Self-injury was associated with significantly higher levels of autistic behaviour within the Down and Fragile X syndrome groups. Within the ASD group, the presence of self-injury was associated with significantly higher levels of impulsivity and hyperactivity, negative affect and significantly lower levels of ability and speech.\ud
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Conclusions: Self-injurious behaviour is prevalent in individuals with ASD and the presence of ASD phenomenology increases the risk of self-injury in individuals with known genetic disorders but without a diagnosis of idiopathic autism. Person characteristics associated with self-injury in ASD indicate a role for impaired behavioural inhibition, low levels of ability and negative affect in the development of self-injurious behaviour
Note on new interesting baryon channels to measure the photon polarization in b -> s gamma
At LHC a large number of b-flavored baryons will be produced. In this note we
propose new baryon modes to determine the photon helicity of the penguin
transition . The decay has the
drawback that the , being neutral and long-lived, will escape
detection most of the time. To overcome this difficulty, transitions of the
type have been proposed, where
denotes an excited state decaying strongly within the detector into the clean
mode . The doublet , that decays weakly, has a number of good
features. The charged baryon will decay into the mode ,
where the ground state hyperon , although it will decay most of the time
outside the detector, can be detected because it is charged. We consider also
the decay of into , where a higher mass state
can decay strongly within the detector. We point out that the initial
transverse polarization of has to be known in all cases. To determine
this parameter through the transition , we distinguish
between different cases, and underline that in some situations one needs {\it
theoretical input} on the asymmetry parameter of the primary
decay. {\it A fortiori} the same considerations apply to the case of the
Bound on the curvature of the Isgur-Wise function of the baryon semileptonic decay Lambda_b -> Lambda_c + l + nu
In the heavy quark limit of QCD, using the Operator Product Expansion, the
formalism of Falk for hadrons or arbitrary spin, and the non-forward amplitude,
as proposed by Uraltsev, we formulate sum rules involving the Isgur-Wise
function of the baryon transition , where the light cloud has for both
initial and final baryons. We recover the lower bound for the slope
obtained by Isgur et al., and we
generalize it by demonstrating that the IW function is an
alternate series in powers of , i.e. . Moreover, exploiting systematically the sum rules, we get an improved
lower bound for the curvature in terms of the slope, . This
bound constrains the shape of the Isgur-Wise function and it will be compelling
in the analysis of future precise data on the differential rate of the baryon
semileptonic decay , that
has a large measured branching ratio, of about 5%.Comment: 16 page
Passiv damping on spacecraft sandwich panels
For reusable and expendable launch vehicles as well as for other spacecraft structural
vibration loads are safety critical design drivers impacting mass and lifetime. Here, the
improvement of reliability and safety, the reduction of mass, the extension of service life, as well
as the reduction of cost for manufacturing are desired. Spacecraft structural design in general is a
compromise between lightweight design and robustness with regard to dynamic loads. The
structural stresses and strains due to displacements caused by dynamic loads can be reduced by
mechanical damping based on passive or active measures. Passive damping systems can be
relatively simple and yet are capable of suppressing a wide range of mechanical vibrations.
Concepts are low priced in development, manufacturing and application as well as maintenancefree.
Compared to active damping measures passive elements do not require electronics, control
algorithms, power, actuators, sensors as well as complex maintenance. Moreover, a reliable
application of active dampers for higher temperatures and short response times (e. g. re-entry
environment) is questionable. The physical effect of passive dampers is based on the dissipation of
load induced energy. Recent activities performed by OHB have shown the function of a passive
friction-damping device for a vertical tail model of the German X-vehicle PHÖNIX but also for
general sandwich structures. The present paper shows brand new results from a corresponding
ESA-funded activity where passive damping elements are placed between the face sheets of large
spacecraft relevant composite sandwich panels to demonstrate dynamic load reduction in vibration
experiments on a shaker. Several passive damping measures are investigated and compared
Renormalization Group approach to Gravity: the running of G and L inside galaxies and additional details on the elliptical NGC 4494
We explore the phenomenology of nontrivial quantum effects on low-energy
gravity. These effects come from the running of the gravitational coupling
parameter G and the cosmological constant L in the Einstein-Hilbert action, as
induced by the Renormalization Group (RG). The Renormalization Group corrected
General Relativity (RGGR model) is used to parametrize these quantum effects,
and it is assumed that the dominant dark matter-like effects inside galaxies is
due to these nontrivial RG effects. Here we present additional details on the
RGGR model application, in particular on the Poisson equation extension that
defines the effective potential, also we re-analyse the ordinary elliptical
galaxy NGC 4494 using a slightly different model for its baryonic contribution,
and explicit solutions are presented for the running of G and L. The values of
the NGC 4494 parameters as shown here have a better agreement with the general
RGGR picture for galaxies, and suggest a larger radial anisotropy than the
previously published result.Comment: 9 pages, 2 figs. Based on a talk presented at the VIII International
Workshop on the Dark Side of the Universe, June 10-15, 2012, Buzios, RJ,
Brazil. v2: typos removed, matches published versio
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