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Identifying sources of error in cross-national questionnaires: Application of an error source typology to cognitive interview data
This article evaluates a Cross National Error Source Typology that was developed as a tool for making cross-national questionnaire design more effective. Cross-national questionnaire design has a number of potential error sources that are either not present or are less common in single nation studies. Tools that help to identify these error sources better inform the survey researcher when improving a source questionnaire that serves as the basis for translation. This article outlines the theoretical and practical development of the typology and evaluates an attempt to apply it to cross-national cognitive interviewing findings from the European Social Survey
Modeling Self-Subtraction in Angular Differential Imaging: Application to the HD 32297 Debris Disk
We present a new technique for forward-modeling self-subtraction of spatially
extended emission in observations processed with angular differential imaging
(ADI) algorithms. High-contrast direct imaging of circumstellar disks is
limited by quasi-static speckle noise and ADI is commonly used to suppress
those speckles. However, the application of ADI can result in self-subtraction
of the disk signal due to the disk's finite spatial extent. This signal
attenuation varies with radial separation and biases measurements of the disk's
surface brightness, thereby compromising inferences regarding the physical
processes responsible for the dust distribution. To compensate for this
attenuation, we forward-model the disk structure and compute the form of the
self-subtraction function at each separation. As a proof of concept, we apply
our method to 1.6 and 2.2 micron Keck AO NIRC2 scattered-light observations of
the HD 32297 debris disk reduced using a variant of the "locally optimized
combination of images" (LOCI) algorithm. We are able to recover disk surface
brightness that was otherwise lost to self-subtraction and produce simplified
models of the brightness distribution as it appears with and without
self-subtraction. From the latter models, we extract radial profiles for the
disk's brightness, width, midplane position, and color that are unbiased by
self-subtraction. Our analysis of these measurements indicates a break in the
brightness profile power law at r~110 AU and a disk width that increases with
separation from the star. We also verify disk curvature that displaces the
midplane by up to 30 AU towards the northwest relative to a straight fiducial
midplane.Comment: Accepted for publication in ApJ, 20 pages, 10 figures, 1 tabl
Accelerated HIV testing for PMTCT in maternity and labour wards is vital to capture mothers at a critical point in the programme at district level
TORONTO AIDS Conference 200
Nerve injury and neuropathic pain - A question of age
The effects of peripheral nerve injury on somatosensory processing and pain are highly dependent upon the age at which the damage occurs. Adult nerve injury rapidly triggers neuropathic pain, but this is not so if the same nerve injury is performed in animals below postnatal day (P) 28, consistent with observations in paediatric patients. However, longitudinal studies show that pain hypersensitivity emerges later in life, when the animal reaches adolescence, an observation that could be of clinical importance. Here we discuss the evidence that the central consequences of nerve damage are critically determined by the status of neuroimmune regulation at different ages. In the first postnatal weeks, when spinal somatosensory circuits are undergoing synaptic reorganisation, the 'default' neuroimmune response is skewed in an anti-inflammatory direction, suppressing the excitation of dorsal horn neurons and preventing the onset of neuropathic pain. As animals grow up and the central nervous system matures, the neuroimmune profile shifts in a pro-inflammatory direction, unmasking a 'latent' pain response to an earlier nerve injury. The data predicts that nerve injury in infancy and childhood could go unnoticed at the time, but emerge as clinically 'unexplained' or 'functional' pain in adolescence
Does Antiretroviral Treatment Reduce Case Fatality Among HIV-Positive Patients with Tuberculosis in Malawi?
SETTING: Thyolo district, Malawi. OBJECTIVES: To report on 1) case fatality among human immunodeficiency virus (HIV) positive tuberculosis (TB) patients while on anti-tuberculosis treatment and 2) whether antiretroviral treatment (ART) initiated during the continuation phase of TB treatment reduces case fatality. DESIGN: Retrospective cohort analysis. METHODS: Comparative analysis of treatment outcomes for TB patients registered between January and December 2004. RESULTS: Of 983 newly registered TB patients receiving diagnostic HIV testing, 658 (67%) were HIV-positive. A total of 132 (20%) patients died during the 8-month course of anti-tuberculosis treatment, of whom 82 (62%) died within the first 2 months of treatment when ART was not provided (cumulative incidence 3.0, 95%CI 2.5-3.6 per 100 person-years). A total of 576 TB patients started the continuation phase of anti-tuberculosis treatment, 180 (31%) of whom were started on ART. The case-fatality rate per 100 person-years was not significantly different for patients on ART (1.0, 95%CI 0.6-1.7) and those without ART (1.2, 95%CI 0.9-1.7, adjusted hazard ratio 0.86, 95%CI 0.4-1.6, P = 0.6) CONCLUSIONS: ART provided in the continuation phase of TB treatment does not have a significant impact on reducing case fatality. Reasons for this and possible measures to reduce high case fatality in the initial phase of TB treatment are discussed
Cortical pain responses in human infants
Despite the recent increase in our understanding of the development of pain processing, it is still not known whether premature infants are capable of processing pain at a cortical level. In this study, changes in cerebral oxygenation over the somatosensory cortex were measured in response to noxious stimulation using real-time near-infrared spectroscopy in 18 infants aged between 25 and 45 weeks postmenstrual age. The noxious stimuli were heel lances performed for routine blood sampling; no blood tests were performed solely for the purpose of the study. Noxious stimulation produced a clear cortical response, measured as an increase in total hemoglobin concentration [HbT] in the contralateral somatosensory cortex, from 25 weeks (mean Delta[HbT] = 7.74 mu mol/L; SE, 1.10). Cortical responses were significantly greater in awake compared with sleeping infants, with a mean difference of 6.63 mu mol/L [95% confidence interval (CI) limits: 2.35, 10.91 mu mol/L; mean age, 35.2 weeks]. In awake infants, the response in the contralateral somatosensory cortex increased with age ( regression coefficient, 0.698 mu mol/L/week; 95% CI limits: 0.132, 1.265 mu mol/L/week) and the latency decreased with age (regression coefficient, -0.9861 mu mol/L/week; 95% CI limits: -1.5361, -0.4361 mu mol/L/week; age range, 25-38 weeks). The response was modality specific because no response was detected after non-noxious stimulation of the heel, even when accompanied by reflex withdrawal of the foot. We conclude that noxious information is transmitted to the preterm infant cortex from 25 weeks, highlighting the potential for both higher-level pain processing and pain-induced plasticity in the human brain from a very early age
Theory and Simulation of the diffusion of kinks on dislocations in bcc metals
Isolated kinks on thermally fluctuating (1/2) screw, edge and
(1/2) edge dislocations in bcc iron are simulated under zero stress
conditions using molecular dynamics (MD). Kinks are seen to perform stochastic
motion in a potential landscape that depends on the dislocation character and
geometry, and their motion provides fresh insight into the coupling of
dislocations to a heat bath. The kink formation energy, migration barrier and
friction parameter are deduced from the simulations. A discrete
Frenkel-Kontorova-Langevin (FKL) model is able to reproduce the coarse grained
data from MD at a fraction of the computational cost, without assuming an a
priori temperature dependence beyond the fluctuation-dissipation theorem.
Analytic results reveal that discreteness effects play an essential r\^ole in
thermally activated dislocation glide, revealing the existence of a crucial
intermediate length scale between molecular and dislocation dynamics. The model
is used to investigate dislocation motion under the vanishingly small stress
levels found in the evolution of dislocation microstructures in irradiated
materials
Teaching Teachers for the Future (TTF) Project: Development of the TTF TPACK survey instrument
This paper presents a summary of the key findings of the TTF TPACK Survey developed and administered for the Teaching the Teachers for the Future (TTF) Project implemented in 2011. The TTF Project, funded by an Australian Government ICT Innovation Fund grant, involved all 39 Australian Higher Education Institutions which provide initial teacher education. TTF data collections were undertaken at the end of Semester 1 (T1) and at the end of Semester 2 (T2) in 2011. A total of 12881 participants completed the first survey (T1) and 5809 participants completed the second survey (T2). Groups of like-named items from the T1 survey were subject to a battery of complementary data analysis techniques. The psychometric properties of the four scales: Confidence - teacher items; Usefulness - teacher items; Confidence - student items; Usefulness- student items, were confirmed both at T1 and T2. Among the key findings summarised, at the national level, the scale: Confidence to use ICT as a teacher showed measurable growth across the whole scale from T1 to T2, and the scale: Confidence to facilitate student use of ICT also showed measurable growth across the whole scale from T1 to T2. Additional key TTF TPACK Survey findings are summarised
Effect of grazing on ship rat density in forest fragments of lowland Waikato, New Zealand
Ship rat (Rattus rattus) density was assessed by snap-trapping during summer and autumn in eight indigenous forest fragments (mean 5 ha) in rural landscapes of Waikato, a lowland pastoral farming district of the North Island, New Zealand. Four of the eight were fenced and four grazed. In each set of four, half were connected with hedgerows, gullies or some other vegetative corridor to nearby forest and half were completely isolated. Summer rat density based on the number trapped in the first six nights was higher in fenced (mean 6.5 rats ha–1) than in grazed fragments (mean 0.5 rats ha–1; P = 0.02). Rats were eradicated (no rats caught and no rat footprints recorded for three consecutive nights) from all eight fragments in January–April 2008, but reinvaded within a month; time to eradication averaged 47 nights in fenced and 19 nights in grazed fragments. A second six-night trapping operation in autumn, 1–3 months after eradication, found no effect of fencing (P = 0.73). Connectedness to an adjacent source of immigrants did not influence rat density within a fragment in either season (summer P = 0.25, autumn P = 0.67). An uncalibrated, rapid (one-night) index of ship rat density, using baited tracking tunnels set in a 50 × 50 m grid, showed a promising relationship with the number of rats killed per hectare over the first six nights, up to tracking index values of c. 30% (corresponding to c. 3–5 rats ha–1). The index will enable managers to determine if rat abundance is low enough to achieve conservation benefits. Our results confirm a dilemma for conservation in forest fragments. Fencing protects vegetation, litter and associated ecological processes, but also increases number of ship rats, which destroy seeds, invertebrates and nesting birds. Maximising the biodiversity values of forest fragments therefore requires both fencing and control of ship rats
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