7,994 research outputs found
Prevalence of mixed genotype hepatitis C virus infections in the UK as determined by genotype‐specific PCR and deep sequencing
The incidence of mixed genotype hepatitis C virus infections in the UK is largely unknown. As the efficacy of direct acting antivirals is variable across different genotypes, treatment regimens are tailored to the infecting genotype, which may pose issues for the treatment of underlying genotypes within undiagnosed mixed genotype HCV infections. There is therefore a need to accurately diagnose mixed genotype infections prior to treatment. PCR-based diagnostic tools were developed to screen for the occurrence of mixed genotype infections caused by the most common UK genotypes, 1a and 3, in a cohort of 506 individuals diagnosed with either of these genotypes. The overall prevalence rate of mixed infection was 3.8% however this rate was unevenly distributed, with 6.7% of individuals diagnosed with genotype 3 harbouring genotype 1a strains and only 0.8% of samples from genotype 1a patients harbouring genotype 3 (p<0.05). Mixed infection samples consisted of a major and a minor genotype, with the latter constituting less than 21% of the total viral load and, in 67% of cases, less than 1% of the viral load. Analysis of a subset of the cohort by Illumina PCR-next generation sequencing resulted in a much greater incidence rate than obtained by PCR. This may have occurred due to the non-quantitative nature of the technique and despite the designation of false positive thresholds based on negative controls
Alternative Buffer-Layers for the Growth of SrBi2Ta2O9 on Silicon
In this work we investigate the influence of the use of YSZ and CeO2/YSZ as
insulators for Metal- Ferroelectric-Insulator-Semiconductor (MFIS) structures
made with SrBi2Ta2O9 (SBT). We show that by using YSZ only the a-axis oriented
Pyrochlore phase could be obtained. On the other hand the use of a CeO2/YSZ
double-buffer layer gave a c-axis oriented SBT with no amorphous SiO2 inter-
diffusion layer. The characteristics of MFIS diodes were greatly improved by
the use of the double buffer. Using the same deposition conditions the memory
window could be increased from 0.3 V to 0.9 V. From the piezoelectric response,
nano-meter scale ferroelectric domains could be clearly identified in SBT thin
films.Comment: 5 pages, 9 figures, 13 refernece
Teaching children with autism spectrum disorder with restricted interests : a review of evidence for best practice
Inclusive education requires teachers to adapt to children’s learning styles. Children with autism spectrum disorder bring challenges to classroom teach- ing, often exhibiting interests restricted to particular topics. Teachers can be faced with a dilemma either to accommodate these restricted interests (RIs) into teaching or to keep them out of the classroom altogether. In this article, we examined all peer-reviewed studies of teaching children with autism spec- trum disorder with RIs published between 1990 and 2014. We find that posi- tive gains in learning and social skills can be achieved by incorporating children’s RIs into classroom practice: Of 20 published studies that examined 91 children, all reported gains in educational attainment and/or social engagement. Negative consequences were limited to a decrease in task per- formance in one child and a transient increase in perseverative behaviors in two children. The evidence supports the inclusion of RIs into classroom prac- tice. Methods of inclusion of RIs are discussed in light of practical difficulties and ideal outcomes
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The Effect of Probing "Don't Know" Responses on Measurement Quality and Nonresponse in Surveys
In survey interviews, “Don’t know” (DK) responses are commonly treated as missing data. One way to reduce the rate of such responses is to probe initial DK answers with a follow-up question designed to encourage respondents to give substantive, non- DK responses. However, such probing can also reduce data quality by introducing additional or differential measurement error. We propose a latent variable model for analyzing the effects of probing on responses to survey questions. The model makes it possible to separate measurement effects of probing from true differences between respondents who do and do not require probing. We analyze new data from an exper- iment which compared responses to two multi-item batteries of questions with and without probing. In this study, probing reduced the rate of DK responses by around a half. However, it also had substantial measurement effects, in that probed answers were often weaker measures of constructs of interest than were unprobed answers. These effects were larger for questions on attitudes than for pseudo-knowledge ques- tions on perceptions of external facts. The results provide evidence against the use of probing of “Don’t know” responses, at least for the kinds of items and respondents considered in this study
Optimality Theory as a Framework for Lexical Acquisition
This paper re-investigates a lexical acquisition system initially developed
for French.We show that, interestingly, the architecture of the system
reproduces and implements the main components of Optimality Theory. However, we
formulate the hypothesis that some of its limitations are mainly due to a poor
representation of the constraints used. Finally, we show how a better
representation of the constraints used would yield better results
Deep radio images of the HEGRA and Whipple TeV sources in the Cygnus OB2 region
Context. The modern generation of Cherenkov telescopes has revealed a new
population of gamma-ray sources in the Galaxy. Some of them have been
identified with previously known X-ray binary systems while other remain
without clear counterparts a lower energies. Our initial goal here was
reporting on extensive radio observations of the first extended and yet
unidentified source, namely TeV J2032+4130. This object was originally detected
by the HEGRA telescope in the direction of the Cygnus OB2 region and its nature
has been a matter of debate during the latest years.
Aims. We aim to pursue our radio exploration of the TeV J2032+4130 position
that we initiated in a previous paper but taking now into account the latest
results from new Whipple and MILAGRO TeV telescopes.
Methods. Our investigation is mostly based on interferometric radio
observations with the Giant Metre Wave Radio Telescope (GMRT) close to Pune
(India) and the Very Large Array (VLA) in New Mexico (USA). We also conducted
near infrared observations with the 3.5 m telescope and the OMEGA2000 camera at
the Centro Astronomico Hispano Aleman (CAHA) in Almeria (Spain).
Results. We present deep radio maps centered on the TeV J2032+4130 position
at different wavelengths. In particular, our 49 and 20 cm maps cover a field of
view larger than half a degree that fully includes the Whipple position and the
peak of MILAGRO emission. Our most important result here is a catalogue of 153
radio sources detected at 49 cm within the GMRT antennae primary beam with a
full width half maximum (FWHM) of 43 arc-minute. Moreover, our
multi-configuration VLA images reveal the non-thermal extended emission
previously reported by us with improved angular resolution.Comment: 10 pages, 8 figures, 1 online catalogue. Accepted for publication in
Astronomy & Astrophysic
Evidence for moving breathers in a layered crystal insulator at 300K
We report the ejection of atoms at a crystal surface caused by energetic
breathers which have travelled more than 10^7 unit cells in atomic chain
directions. The breathers were created by bombardment of a crystal face with
heavy ions. This effect was observed at 300K in the layered crystal muscovite,
which has linear chains of atoms for which the surrounding lattice has C_2
symmetry. The experimental techniques described could be used to study
breathers in other materials and configurations.Comment: 7 pages, 3 figure
Motor kinematic differences in children with autism sepectrum disorder : ecological gameplay with a sensorised toy
Background Evidence suggests gross motor differences are present in children with Autism Spectrum Disorder (ASD) from birth. Trevarthen and Delafield-Butt (2013) proposed that one of the early markers of ASD are abnormalities in the development of intentional movements, which are present before the manifestations of symptoms typically associated with autism, like deficiencies in social interaction and communication. A growing body of literature demonstrates kinematic and action patterns differences in children and adults with ASD. However, these experiments typically require expensive laboratory-based optical motion tracking systems. Here, we developed bespoke, sensorised wooden cubes for motor assessment of children’s play and report on the kinematic and action pattern differences of the children with autism compared to children developing typically. Objectives A description of ASD-specific action patterns and kinematics using sensorised toys. Methods Participants. Children 3 to 5 years diagnosed with ASD (n = 15) recruited from the Scottish Centre for Autism, Glasgow, UK. Children 3 to 5 years old developing typically recruited from nurseries in Glasgow, UK. Adults 20 to 25 years old without ASD recruited from Glasgow, UK. The study was approved by the University of Strathclyde Ethics Committee and consent obtained from the parents of children or the adults. In the case of the children with ASD, pre-screening with Vineland-II, AQ-Child and Leiter-R Brief IQ was performed. Procedure. The children were seated at a table and instructed to play two simple games that involved moving the cube from one position to another: a Serially Organized Action (SOA) game and a Single Repetitive Action (SRA) game. The first required complex motor sequencing and engagement with the experimenter, while the second consisted of a simple repetitive movement. Each game produced a single measured movement to a goal with 25 iterations or repetitions to yield 50 movements in total. An electronic board inside the cubes was equipped with tri-axial magnetometer, gyroscope and accelerometer wirelessly transferred the cube’s motion data to a laptop. The signal (raw motion data) was extracted through a Matlab-based platform and analysed. Data Analysis. Kinematic features of movement duration; maximum value of acceleration, velocity, and jerk during each movement; time to maximum value; % duration to maximum value; and the acceleration, velocity, and jerk action patterns profiles were calculated. Results The jerk profile of children with ASD was significantly different, showing increased maximum jerk, reduced time to maximum value and & duration to maximum value, and lower variability than typically developing children. Further, movement duration was shorter compared to age-matched typically developing children, and maximum velocity was significantly higher in children with ASD compared to children developing typically. Conclusion The increased jerk values and onset times in the ASD group are a particularly interesting finding that support new data appearing by other groups. It appeared, especially in the SRA game, that when moving the cube from one position to the next, the children with autism impacted on the surface of the table with greater velocity and typically included the resulting force immediately into to the next movement, giving it a greater jerk value in a shorter span of time that typically children. Typically developing children, on the other hand, paused for a moment (>100 ms) before commencing the next movement. Further, children with autism did not enjoy the SRA game, but they did enjoy the simpler, more repetitive SOA one. The repetitive simplicity of the SOA game and its resulting jerk profile appears to report on a particular behavioural motor feature distinct to ASD, namely stopping an action and starting a new one, while also describing an underlying motor difference that may contribute to it
Prognostic Information for Known Genetic Carriers of RB1 Pathogenic Variants (Germline and Mosaic)
OBJECTIVE: To compare the number of tumors per eye for mosaic carriers of RB1 pathogenic variants with full germline variants and the conversion from unilateral to bilateral disease. DESIGN: Retrospective cohort study comparing patients with retinoblastoma and different genetic subtypes (HP: high penetrant, LP: low penetrant & mosaicism). SUBJECTS: Data were analysed between 1992 and 2018 at the Retinoblastoma Unit, Royal London Hospital, London UK. All familial patients had a parent with a known pathogenic variant even if the parent did not manifest the disease. MAIN OUTCOME MEASURES: Number of tumors per eye in children who developed retinoblastoma in that eye. Other outcomes included total number of tumors per patient, age at diagnosis, laterality at presentation and later, sex and stage according to International Intraocular Retinoblastoma Classification RESULTS: 111 patients were included: 64 full germline, familial patients (53 HP and 11 LP) & 47 were mosaic patients. 12 (23%) of HP patients were unilateral and 8 of 12 (67%) developed tumors in their previously unaffected eye. 34 (72%) of mosaic patients were unilateral and only 2 (6%) developed tumors in their unaffected eye. Age at diagnosis was higher in mosaic patients (median 22 months) than HP patients (median 7) (p<0.00002). Number of tumors per eye was fewer in patients with mosaic alleles (median 1.0 range 1-6) compared to patients with HP alleles (median 3.0 range 1-8) (p<0.0003). All three children (4 eyes) with mosaicism and more than 2 tumors per eye had high levels of mosaicism. CONCLUSIONS: Children with mosaic alleles have fewer tumors per eye compared to those with known high penetrant pathogenic variants and are more likely to remain unilateral. The level of mosaicism has an impact on laterality and number of tumors
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