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In patients with Down's syndrome, late onset seizures may have a relationship with the clinical onset of dementia.
to explore the profile of patients in Memory Clinic (MC) in Barnet Learning Disability Service.
Retrospective study of case notes of 41 patients with Learning Disability (LD) who were registered in MC from 2004 to 2007.
Among the patients with different level of LD attending MC the gender distribution was as follows 27 (65.9%) were women and 14 (34.1%) were men. Most of the patients 25 (60.9%) were middle aged (35-49 years old). Patients with Down's syndrome consisted of 31(75.6%). 17 (41.5%) patients were diagnosed with dementia. 24(58.5%) showed borderline results. All patients with diagnosis of dementia had Down's syndrome whereas among those without definitive diagnose of dementia predominated people with mild to moderate LD.
Neuropsychological testing included Dementia Questionnaire for Mentally Retarded Persons (DMR), Psychiatric Assessment Schedule for Adults with Developmental Disabilities (PAS-AD).
12 (26.3%) had epilepsy. The seizure started during childhood and at middle age. Those with childhood epilepsy had the better seizure control. In individuals with late onset epilepsy the beginning of the seizures preceded cognitive decline.
The analysis of patients registered in MC showed the prevalence of middle aged persons with Down's syndrome. The dementia was established in 41.5% of patients with Down's syndrome.
A bimodal distribution for seizure onset in childhood and middle age was described. Late onset of epilepsy was associated with clinical onset of dementia.
Background: Focal cortical dysplasias (FCDs) are congenital structural abnormalities of the brain, and represent the most common cause of medication-resistant focal epilepsy in children and adults. Recent studies have shown that somatic mutations (i.e. mutations arising in the embryo) in mTOR pathway genes underlie some FCD cases. Specific therapies targeting the mTOR pathway are available. However, testing for somatic mTOR pathway mutations in FCD tissue is not performed on a clinical basis, and the contribution of such mutations to the pathogenesis of FCD remains unknown. Aim: To investigate the feasibility of screening for somatic mutations in resected FCD tissue and determine the proportion and spatial distribution of FCDs which are due to low-level somatic mTOR pathway mutations. Methods: We performed ultra-deep sequencing of 13 mTOR pathway genes using a custom HaloPlexHS target enrichment kit (Agilent Technologies) in 16 resected histologically-confirmed FCD specimens. Results: We identified causal variants in 62.5% (10/16) of patients at an alternate allele frequency of 0.75–33.7%. The spatial mutation frequency correlated with the FCD lesion’s size and severity. Conclusions: Screening FCD tissue using a custom panel results in a high yield, and should be considered clinically given the important potential implications regarding surgical resection, medical management and genetic counselling.
Interfacial dislocations (IDs) and half-loop arrays (HLAs) present in the
epilayers of 4H-SiC crystal are known to have a deleterious effect on device
performance. Synchrotron X-ray Topography studies carried out on n-type 4H-SiC
offcut wafers before and after epitaxial growth show that in many cases BPD
segments in the substrate are responsible for creating IDs and HLAs during CVD
growth. This paper reviews the behaviors of BPDs in the substrate during the
epitaxial growth in different cases: (1) screw-oriented BPD segments
intersecting the surface replicate directly through the interface during the
epitaxial growth and take part in stress relaxation process by creating IDs and
HLAs (Matthews-Blakeslee model  ); (2) non-screw oriented BPD half loop
intersecting the surface glides towards and replicates through the interface,
while the intersection points convert to threading edge dislocations (TEDs) and
pin the half loop, leaving straight screw segments in the epilayer and then
create IDs and HLAs; (3) edge oriented short BPD segments well below the surface
get dragged towards the interface during epitaxial growth, leaving two long
screw segments in their wake, some of which replicate through the interface and
create IDs and HLAs. The driving force for the BPDs to glide toward the
interface is thermal stress and driving force for the relaxation process to
occur is the lattice parameter difference at growth temperature which results
from the doping concentration difference between the substrate and epilayer.
A review is presented of Synchrotron X-ray Topography and KOH etching studies carried out on n type 4H-SiC offcut substrates before and after homo-epitaxial growth to study defect replication and strain relaxation processes and identify the nucleation sources of both interfacial dislocations (IDs) and half-loop arrays (HLAs) which are known to have a deleterious effect on device performance. We show that these types of defects can nucleate during epilayer growth from: (1) short segments of edge oriented basal plane dislocations (BPDs) in the substrate which are drawn by glide into the epilayer; and (2) segments of half loops of BPD that are attached to the substrate surface prior to growth which also glide into the epilayer. It is shown that the initial motion of the short edge oriented BPD segments that are drawn from the substrate into the epilayer is caused by thermal stress resulting from radial temperature gradients experienced by the wafer whilst in the epi-chamber. This same stress also causes the initial glide of the surface half-loop into the epilayer and through the advancing epilayer surface. These mobile BPD segments provide screw oriented segments that pierce the advancing epilayer surface that initially replicate as the crystal grows. Once critical thickness is reached, according to the Mathews-Blakeslee model , these screw segments glide sideways under the action of the mismatch stress leaving IDs and HLAs in their wake. The origin of the mismatch stress is shown to be associated with lattice parameter differences at the growth temperature, arising from the differences in doping concentration between substrate and epilayer.
Autoimmune-mediated basal ganglia dysfunction is implicated in the pathophysiology of neuropsychiatric disorders commonly manifesting with obsessive–compulsive features (e.g. Sydenham chorea). The relationship between autoimmunity and primary obsessive–compulsive disorder (OCD), however, is less clear.
To pool data on serum and cerebrospinal fluid (CSF) anti-basal ganglia antibody (ABGA) positivity in primary OCD (without neurological or autoimmune comorbidity) relative to controls or neuropsychiatric disorders previously associated with increased odds of ABGA positivity.
We performed electronic database and hand-searches for studies meeting pre-specified eligibility criteria from which we extracted data using a standardised form. We calculated pooled estimates of ABGA positivity using a random-effects model.
Seven case–control studies totalling 844 participants met the eligibility criteria. Meta-analysis showed that a significantly greater proportion of those with primary OCD were ABGA seropositive compared with various controls (odds ratio (OR) = 4.97, 95% CI 2.88–8.55, P<0.00001). This effect was not associated with heterogeneity or publication bias, and remained significant after stratifying the analysis by age, gender, disease severity, illness duration, immunostaining methodology, study quality, publication type, kind of control group, and sample size. There were no significant differences in ABGA seropositivity for comparisons between primary OCD and Tourette syndrome, attention-deficit hyperactivity disorder or paediatric acute-onset neuropsychiatric syndrome. Results of one study testing CSF samples showed that a significantly greater proportion of participants with primary OCD were ABGA CSF-positive compared with healthy controls (OR = 5.60, 95% CI 1.04–30.20, P = 0.045).
Odds of ABGA seropositivity are increased fivefold in primary OCD compared with controls, but are comparable to those associated with disorders previously associated with ABGA, providing circumstantial evidence of autoimmunity in a subset of those with primary OCD. Further experimental studies are needed to ascertain whether this relationship is causal.
Tamarisk (a.k.a. saltcedar, Tamarix spp.) is an invasive plant species that occurs throughout western riparian and wetland ecosystems. It is implicated in alterations of ecosystem structure and function and is the subject of many local control projects, including removal using heavy equipment. We evaluated short-term vegetation responses to mechanical Tamarix spp. removal at sites ranging from 2 to 5 yr post-treatment along the Virgin River in Nevada, USA. Treatments resulted in lower density and cover (but not eradication) of Tamarix spp., increased cover of the native shrub Pluchea sericia (arrow weed), decreased density and cover of all woody species combined, increased density of both native annual forbs and the nonnative annual Salsola tragus (prickly Russian-thistle), and lower density of nonnative annual grasses. The treated plots had lower mean woody species richness, but greater herbaceous species richness and diversity. Among herbaceous species, native taxa increased in richness whereas nonnative species increased in both species richness and diversity. Thus, efforts to remove Tamarix spp. at the Virgin River reduced vegetative cover contributing to fuel loads and probability of fire, and resulted in positive effects for native plant diversity, with mixed effects on other nonnative species. However, absolute abundances of native species and species diversity were very low, suggesting that targets of restoring vegetation to pre-invasion conditions were not met. Longer evaluation periods are needed to adequately evaluate how short-term post-treatment patterns translate to long-term patterns of plant community dynamics.
The example after Theorem 3.2 showed that for a continuous distribution function F such as for U[0, 1], the set of all possible functions √n(Fn − F), even for n = 1, is nonseparable in the sup norm, and all its subsets are closed, including those corresponding to nonmeasurable sets of possible values of the observation X1. Therefore, the classical definition of convergence in law, or weak convergence, which works in separable metric spaces, does not work in this case, So, in Chapter 3, functions f* and upper expectations E* were used to get around measurability problems.
But, in the classical Glivenko–Cantelli theorem, saying that supx |(Fn − F)(x)| → 0 almost surely as n → ∞ for any distribution function F on ℝ and its empirical distribution functions Fn (RAP, Theorem 11.4.2), there is no measurability problem. The supremum is measurable, as it can be restricted to rational x by right-continuity of Fn and F. The collection C of left half-lines (−∞, x] is linearly ordered by inclusion and so has S(C) = 1, and for it, not only the Glivenko–Cantelli theorem but, after suitable formulations (Theorem 1.8 or, less specifically, Chapter 3), the uniform central limit theorem (Donsker property) holds for any probability measure P on the Borel sets of ℝ.
This book developed out of some topics courses given at M.I.T. and my lectures at the St.-Flour probability summer school in 1982. The material of the book has been expanded and extended considerably since then. At the end of each chapter are some problems and notes on that chapter.
Starred sections are not cited later in the book except perhaps in other starred sections. The first edition had several double-starred sections in which facts were stated without proofs. This edition has no such sections.
The following, not proved in the first edition, now are: (i) for Donsker's theorem on the classical empirical process αn := √n(Fn − F), and the Komlós–Major–Tusnády strengthening to give a rate of convergence, the Bretagnolle–Massart proof with specified constants; (ii) Massart's form of the Dvoretzky–Kiefer–Wolfowitz inequality for αn with optimal constant; (iii) Talagrand's generic chaining approach to boundedness of Gaussian processes, which replaces the previous treatment of majorizing measures; (iv) characterization of uniform Glivenko–Cantelli classes of functions (from a paper by Dudley, Giné, and Zinn, but here with a self-contained proof); (v) Giné and Zinn's characterization of uniform Donsker classes of functions; (vi) its consequence that uniformly bounded, suitably measurable classes of functions satisfying Pollard's entropy condition are uniformly Donsker; and (vii) Bousquet, Koltchinskii, and Panchenko's theorem that a convex hull preserves the uniform Donsker property.