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To develop latent classes of exposure to traumatic experiences before the age of 13 years in an urban community sample and to use these latent classes to predict the development of negative behavioral outcomes in adolescence and young adulthood.
A total of 1815 participants in an epidemiologically based, randomized field trial as children completed comprehensive psychiatric assessments as young adults. Reported experiences of nine traumatic experiences before age 13 years were used in a latent class analysis to create latent profiles of traumatic experiences. Latent classes were used to predict psychiatric outcomes at age ⩾13 years, criminal convictions, physical health problems and traumatic experiences reported in young adulthood.
Three latent classes of childhood traumatic experiences were supported by the data. One class (8% of sample), primarily female, was characterized by experiences of sexual assault and reported significantly higher rates of a range of psychiatric outcomes by young adulthood. Another class (8%), primarily male, was characterized by experiences of violence exposure and reported higher levels of antisocial personality disorder and post-traumatic stress. The final class (84%) reported low levels of childhood traumatic experiences. Parental psychopathology was related to membership in the sexual assault group.
Classes of childhood traumatic experiences predict specific psychiatric and behavioral outcomes in adolescence and young adulthood. The long-term adverse effects of childhood traumas are primarily concentrated in victims of sexual and non-sexual violence. Gender emerged as a key covariate in the classes of trauma exposure and outcomes.
The NASA Discovery mission EPOXI, utilizing the Deep Impact flyby spacecraft, comprises two phases: EPOCh (Extrasolar Planet Observation and Characterization) and DIXI (Deep Impact eXtended Investigation). With EPOCh, we use the 30-cm high resolution visible imager to obtain ultraprecise photometric light curves of known transiting planet systems. We will analyze these data for evidence of additional planets, via transit timing variations or transits; for planetary moons or rings; for detection of secondary eclipses and the constraint of geometric planetary albedos; and for refinement of the system parameters. Over a period of four months, EPOCh observed four known transiting planet systems, with each system observed continuously for several weeks. Here we present an overview of EPOCh, including the spacecraft and science goals, and preliminary photometry results.
EPOXI (EPOCh + DIXI) is a NASA Discovery Program Mission of Opportunity using the Deep Impact flyby spacecraft. The EPOCh (Extrasolar Planet Observation and Characterization) Science Investigation will gather photometric time series of known transiting exoplanet systems from January through August 2008. Here we describe the steps in the photometric extraction of the time series and present preliminary results of the first four EPOCh targets.
Investigations in recent years of the ecological structure and processes of the Southern Ocean have almost exclusively taken a bottom-up, forcing-by-physical-processes approach relating various species' population trends to climate change. Just 20 years ago, however, researchers focused on a broader set of hypotheses, in part formed around a paradigm positing interspecific interactions as central to structuring the ecosystem (forcing by biotic processes, top-down), and particularly on a “krill surplus” caused by the removal from the system of more than a million baleen whales. Since then, this latter idea has disappeared from favour with little debate. Moreover, it recently has been shown that concurrent with whaling there was a massive depletion of finfish in the Southern Ocean, a finding also ignored in deference to climate-related explanations of ecosystem change. We present two examples from the literature, one involving gelatinous organisms and the other involving penguins, in which climate has been used to explain species' population trends but which could better be explained by including species interactions in the modelling. We conclude by questioning the almost complete shift in paradigms that has occurred and discuss whether it is leading Southern Ocean marine ecological science in an instructive direction.
We report on a new technique that we used to accurately time
the velocity of a cluster beam. It involves deflecting particles
away from their usual beam path by scattering with an ablation
plume. We were able to time the occurrence of a C60
cluster beam to better than 0.2%. This technique was critical
in recent light-force polarizabilities experiments.
The identification of fluctuating confusion is central to improving the differential diagnosis of the common dementias.
To determine the value of two rating scales to measure fluctuating confusion.
The agreement between the clinician-rated scale and the scale completed by a non-clinician was determined. Correlations between the two scales were calculated; variability in attention was calculated on a computerised cognitive assessment and variability in delta rhythm on an electroencephalogram (EEG).
The Clinician Assessment of Fluctuation and the computerised cognitive assessment were completed for 155 patients (61 Alzheimer's disease, 37 dementia with Lewy bodies, 22 vascular dementia, 35 elderly controls). A subgroup (n=40) received a further evaluation using the One Day Fluctuation Assessment Scale and an EEG. The two scales correlated significantly with each other, and with the neuropsychological and electrophysiological measures of fluctuation.
Both scales are useful instruments for the clinical assessment of fluctuation in dementia.
This study examined the postulate that training
production of syntactically complex sentences results in
generalization to less complex sentences that have processes
in common with treated structures. Three agrammatic aphasic
patients were trained to produce wh-movement structures,
object clefts and/or object extracted who-questions,
while generalization between these structures was tested.
One NP-movement structure, passive sentences, also was
tested for control purposes. Wh-movement occurs
from the direct object position to specifier position
in the complementizer phrase [SPEC, CP] for both
wh-movement structures. In who-questions
movement occurs in the matrix sentence, whereas, in object
clefts movement occurs within an embedded relative clause,
rendering them the most complex. Results showed robust
generalization effects from object clefts to matrix who-question
for 1 participant (D.L.); however, no generalization was
noted from who-questions to object clefts for
another (F.P.), and 1 participant (C.H.) showed acquisition
of who-questions, but not object clefts, during
the baseline condition without direct treatment. As expected,
none of the participants showed improved production of
passives. These findings supported those derived from our
previous studies, indicating that generalization is enhanced
not only when target structures are related along dimensions
articulated by linguistic theory, but also when the direction
of treatment is from more to less complex structures. The
present findings also support proposals that projections
of higher levels in the syntactic treatment are dependent
on successful projection of lower levels. For our participants,
training movement within CP in a lower (embedded) clause
resulted in their ability to project to CP at higher levels.
(JINS, 1998, 4, 661–674.)
To describe phenomena that occur at different time scales,
computational models of the brain must incorporate different levels
of abstraction. At time scales of approximately 1/3 of a second,
orienting movements of the body play a crucial role in cognition and
form a useful computational level – more abstract than that
used to capture natural phenomena but less abstract than what is
traditionally used to study high-level cognitive processes such as
reasoning. At this “embodiment level,” the constraints
of the physical system determine the nature of cognitive operations.
The key synergy is that at time scales of about 1/3 of a second, the
natural sequentiality of body movements can be matched to the natural
computational economies of sequential decision systems through a
system of implicit reference called deictic in which pointing
movements are used to bind objects in the world to cognitive programs.
This target article focuses on how deictic bindings make it possible
to perform natural tasks. Deictic computation provides a mechanism
for representing the essential features that link external sensory
data with internal cognitive programs and motor actions. One of the
central features of cognition, working memory, can be related to
moment-by-moment dispositions of body features such as eye
movements and hand movements.
The majority of commentators agree that the time to focus on
embodiment has arrived and that the disembodied approach that was
taken from the birth of artificial intelligence is unlikely to provide
a satisfactory account of the special features of human intelligence.
In our Response, we begin by addressing the general comments and
criticisms directed at the emerging enterprise of deictic and embodied
cognition. In subsequent sections we examine the topics that
constitute the core of the commentaries: embodiment mechanisms, dorsal
and ventral visual processing, eye movements, and learning.
Robert Perry, Department of Neuropathology, Newcastle General Hospital,Ian McKeith, University of Newcastle upon Tyne,Elaine Perry, MRC Neurochemical Pathology Unit, Newcastle General Hospital
Information regarding non-cognitive symptoms in patients with senile dementia of Lewy body type (SDLT) was abstracted from a number of sources including postmortem, clinical and prospective studies. Psychotic symptoms occur in more than 80% of patients with SDLT. Visual hallucinations are especially common. Visual hallucinations, auditory hallucinations and delusional misidentification occur significantly more often in SDLT than Alzheimer's disease. Major depression occurs in 15% of patients with SDLT and Alzheimer's disease. Falls are common in SDLT occurring in 50% or more of patients, but not all studies find them to be significantly more common in SDLT than Alzheimer's disease. Little is known about the association of psychotic symptoms, depression or falls in SDLT and no effective treatment strategies are established.
Other important symptoms such as anxiety, aggression, wandering and inappropriate sexual activity have not been systematically studied.
It is necessary to set the scene by considering the prevalence rates and the importance of noncognitive features in patients with Alzheimer's disease as there is only rudimentary information available concerning these symptoms in Lewy body dementia (LBD). Fifteen to 30% of patients with Alzheimer's disease in contact with clinical services suffer from concurrent depression and the prevalence rate of psychotic symptoms in clinical samples exceeds 60%. Psychotic symptoms cause distress to carers and to the patients themselves. They reduce the likelihood of people continuing to live in their own homes (Steele et al., 1990), are associated with increased family discord and there is accumulating evidence to suggest that the presence of psychotic symptoms predicts a more rapid rate of cognitive decline (Rosen & Zubenko, 1991).
Little data are available about the course or incidence of depression in dementia sufferers.
Monthly follow-up data over one year is reported regarding depression in a cohort of 124 dementia sufferers. Dementia was diagnosed according to DSM–III–R criteria. Depression was assessed with the Cornell Depression Scale and diagnosed according to RDC criteria. Cognitive functioning was assessed with the CAMCOG.
Eighty-nine of the 124 patients completed the follow-up. The annual incidence rates of RDC major depression and RDC minor depression were 10.6% and 29.8%, respectively. Twenty per cent of patients with depression experienced these symptoms for six months or longer. Patients with vascular dementia were significantly more likely to experience three or more months of depression than patients with other dementias. RDC minor depression was highly persistent among 23.8% of sufferers.
Depression is persistent in patients with vascular dementia. Some patients with minor depression have a dysthymia-like disorder.
There has been discussion about the possible occurrence of post-traumatic stress disorder (PTSD) in mothers after difficult childbirth.
Four cases with a symptom profile suggestive of PTSD commencing within 48 hours of childbirth are presented.
The PTSD was in each case associated with the delivery. In each case, there was an associated depressive illness. All four had persistent disorders, and two had difficulties with mother/infant attachment.
As confirmed by other reports, the prevalence of PTSD associated with childbirth is a matter of concern.
Depth profiles of intrinsic in-plane, biaxial stresses were obtained as a function of τ, the 1/e penetration depth, in a 1.0 um thick planar d. c. magentron sputter deposited molybdenum film using asymmetric grazing incidence x-ray diffraction (GIXD). τ was varied between 20 and 276 Å. The stresses σ11 and σ22 were characterized in the directions parallel and perpendicular to the long axis of the cathode respectively using a cos2φ method. The results show that starting from τ=17Å, σ11 and σ22 are compressive and become rapidly more compressive with a minimum at τ ∼ 20 - 40 Å thereafter increasing gradually toward tensile values. The reasons for the shape of the stress gradient are not well understood but may be related to the relaxation of the stresses at the tops of the columnar Zone T-type microstructure and to the oxygen gradient in the film.
Residual strains and microstresses are evaluated for both phase of a hot-pressed, fine-grained α-alumina reinforced with 25 wt% (29 vol%) single-crystal silicon carbide whiskers at temperatures from 25 to 1000 °C. The sample was maintained in a nonoxidizing environment while measurements of the interplaner spacing of alumina (146) and SiC (511 + 333) were made using X-ray diffraction methods. The residual strains were profiled at temperature increments of 250 °C from which the corresponding microstresses were calculated. Linear extrapolation of the SiC ε33 profile indicates that the strains are completely relaxed at a temperature of approximately 1470 °C. These residual stress relaxation results suggest that elevated temperature toughness and fracture strength of this composite may result from cooperative mechanisms.
A method for using grazing incidence x-ray diffraction (GIXD) for profiling composition changes with depth of photovoltaic quality thin films is presented. The average thickness of the first layer in a multi-layer film of CuIn2Se3.5/CuInSe2/Mo and the variation in solid solution composition of a Cu(In1-xGax)Se2 (CIGS) film with depth are solved using this method. The phase volume fraction and the phase composition profiles are developed from peak intensity and d-spacing measurements respectively at a series of fixed incident angles corresponding to a set of increasing 1/e penetration depths, τ. Inverse Laplace and numerical methods are applied to the τ profiles converting them to true depth profiles. Vegard's law is applied to the d-spacing vs z-profile to obtain x in the formula Cu(In1-xGax)Se2. The results show that an ∼1 μm thick layer of CuIn2Se3.5 is present on the surface of the multi-layer film and that the CIGS film consists of a Ga rich surface layer ∼2000 Å thick followed by a gradual decrease in Ga content with increasing depth. This gradient appears to be desirable for producing photovoltaic quality CIGS films.
Intrinsic stresses as a function of σ, the 1/e penetration depth were measured for a smooth, 1μm thick, fine grained, cylindrical post magnetron sputtered molybdenum film deposited on a vycor glass substrate in the dynamic deposition mode. Using grazing incidence diffraction and the Mo (321) reflection, lattice spacing profiles were determined for τ values from 200-4400 Å. The in-plane intrinsic stresses parallel and perpendicular to the post axis were determined employing the ϕ-integral method and assuming elastic isotropy. The results were related to the surface structure and composition profiles via atomic force microscopy (AFM) and auger electron spectroscopy (AES) respectively.
In situ reinforced (ISR) silicon nitride ceramics have been developed to have microstructures that mimic the best whisker containing ceramic matrix composites. Large, interlocking needle-like grains of beta silicon nitride can be produced throughout these materials to create an isotropic, high-temperature ceramic with high fracture toughness (˜9 MPa√m), good high-temperature strength (4 Pt MOR = 750 MPa at 25°C and 500 MPa at 1375°C), high Weibull modulus (m >20), and low creep at high temperature. Since these materials do not rely on transforming metastable phase inclusions as a toughening mechanism, their fracture resistance is virtually insensitive to temperature. The high crack growth resistance of these ceramics also yields a material which is extremely defect tolerant. Residual MOR strengths of 300–400 MPa are typical after multiple 50-kg Vicker's indentations of the sample tensile surface. After abrasive particle impact, the biaxial strengths of the in situ reinforced ceramics are typically more than twice that of traditional, fine-grained silicon nitrides.
Unlike ceramic composites toughened using whisker additives, the in situ reinforcement approach to silicon nitride development does not require the use of complicated whisker dispersion techniques for green processing, nor is shape-limiting hot pressing required for densification during sintering.
We evaluated trends in the use of echocardiography among residents of Olmsted County, Minnesota, from January 1, 1975, through June 30, 1987. Annual examinations per 100,000 population among Olmsted County residents increased 6-fold from 264 in 1975 to 1,644 in 1986. Given the pattern of echo use in Olmsted County, these population-based data project a potential annual utilization of 4 million echo exams in the United States. Marked increases over time in labeling of patients with regurgitant valvular heart disease were noted following the introduction of Doppler echocardiography. The diagnostic labeling associated with this evolving technology and the resultant apparent epidemic of valvular regurgitation present a significant clinical technology assessment dilemma.
We have made a polarimetric survey of 84 quasi-stellar objects, to supplement published polarization measurements for two samples of quasars identified with flat-spectrum (core-dominant) radio sources in 5 GHz surveys made at Bonn (Kühr 1980) and at the VLA (Perley 1982). The observations were made using the McDonald 2.1m Struve reflector and the polarimeter described by Breger (1979); the typical accuracy is 0.5% for an 18 mag object after half an hour. Earlier surveys, such as those by Stockman, Moore and Angel (1984), included objects of various radio spectral types, and only a small fraction of the objects showed high polarization (> 3%), but our sample of flat-spectrum quasars reveals many more (about half) of the objects to be highly polarized. Some of them are, expectedly, of the BL Lac class, but many of them have strong broad emission lines. There are two striking correlations among the results:
(1)The degree of polarization is strongly correlated with the dominance of the radio core - specifically, with the ratio, R, of core to lobe luminosity (Fig. 1). For example, about 75% of the objects with log R > 1.25 and redshift z < 1 have p > 3%. This relation implies that if the radio core radiation is beamed, as seems likely, then so is the optical synchrotron component.
(2)The fraction of objects with p > 3% is inversely correlated with redshift (e.g. Fig. 2). The most likely interpretation of this result is that quasars' degree of polarization decreases with decreasing rest wavelength, and the shorter wavelengths are shifted into our wide observational passband at higher redshifts.
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