1,675 research outputs found

    Buying Time 2000: Television Advertising in the 2000 Federal Elections

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    Summarizes a study of political television advertising in the 2000 federal primaries and elections with a focus on the use of the issue ad loophole to evade campaign finance laws. Questions the standard used to differentiate issue ads from election ads

    New Relations for Three-Dimensional Supersymmetric Scattering Amplitudes

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    We provide evidence for a duality between color and kinematics in three-dimensional supersymmetric Chern-Simons matter theories. We show that the six-point amplitude in the maximally supersymmetric, N=8, theory can be arranged so that the kinematic factors satisfy the fundamental identity of three-algebras. We further show that the four- and six-point N=8 amplitudes can be "squared" into the amplitudes of N=16 three-dimensional supergravity, thus providing evidence for a hidden three-algebra structure in the dynamics of the supergravity.Comment: 8 pages, 2 figure

    Quantitative Analysis of Non-Linear Probabilistic State Estimation Filters for Deployment on Dynamic Unmanned Systems

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    The work conducted in this thesis is a part of an EU Horizon 2020 research initiative project known as DigiArt. This part of the DigiArt project presents and explores the design, formulation and implementation of probabilistically orientated state estimation algorithms with focus towards unmanned system positioning and three-dimensional (3D) mapping. State estimation algorithms are considered an influential aspect of any dynamic system with autonomous capabilities. Possessing the ability to predictively estimate future conditions enables effective decision making and anticipating any possible changes in the environment. Initial experimental procedures utilised a wireless ultra-wide band (UWB) based communication network. This system functioned through statically situated beacon nodes used to localise a dynamically operating node. The simultaneous deployment of this UWB network, an unmanned system and a Robotic Total Station (RTS) with active and remote tracking features enabled the characterisation of the range measurement errors associated with the UWB network. These range error metrics were then integrated into an Range based Extended Kalman Filter (R-EKF) state estimation algorithm with active outlier identification to outperform the native approach used by the UWB system for two-dimensional (2D) pose estimation.The study was then expanded to focus on state estimation in 3D, where a Six Degreeof-Freedom EKF (6DOF-EKF) was designed using Light Detection and Ranging (LiDAR) as its primary observation source. A two step method was proposed which extracted information between consecutive LiDAR scans. Firstly, motion estimation concerning Cartesian states x, y and the unmanned system’s heading (ψ) was achieved through a 2D feature matching process. Secondly, the extraction and alignment of ground planes from the LiDAR scan enabled motion extraction for Cartesian position z and attitude angles roll (θ) and pitch (φ). Results showed that the ground plane alignment failed when two scans were at 10.5◦ offset. Therefore, to overcome this limitation an Error State Kalman Filter (ES-KF) was formulated and deployed as a sub-system within the 6DOF-EKF. This enabled the successful tracking of roll, pitch and the calculation of z. The 6DOF-EKF was seen to outperform the R-EKF and the native UWB approach, as it was much more stable, produced less noise in its position estimations and provided 3D pose estimation

    Parvovirus B19 infection in pediatric transplant patients

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    Evidence of recent parvovirus virus infection (as determined by the presence of a positive IgM antibody titer) without other identified causes of anemia was found in 5 of 26 pediatric solid-organ transplant recipients evaluated for moderate-to-severe anemia between June 1990 and July 1991. Anemia tended to be chronic (median duration of anemia at the time of diagnosis was 12 weeks) and was associated with normal red blood cell indices in the absence of reticulocytes. The median age of the children at the time of presentation with anemia due to parvovirus was 1.8 years at a median time of 8 months after transplantation. Four of the 5 children were treated with i.v. immunoglobulin because of persistance of anemia requiring blood transfusions. A response characterized by an increase in reticulocyte count and normalization of hemoglobin was seen in each of these patients 2-4 weeks after treatment. The remaining patient experienced a spontaneous recovery from her anemia. Parvovirus infection should be included in the differential diagnosis of solid-organ transplant recipients presenting with severe anemia associated with low or absent reticulocytes

    AN INVESTIGATION INTO THE EFFECTS OF A SIMULATED EFFUSION IN HEALTHY SUBJECTS ON KNEE KINEMATICS AND LOWER LIMB MUSCLE ACTIVITY DURING A SINGLE LEG DROP LANDING

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    Arthrogenic muscle inhibition (AMI) is defined as an ongoing reflex inhibition of the musculature surrounding a joint following distension or damage to the structures of that joint [Hopkins and Ingersoll, 2000]. AMI following joint injury may affect movement and muscle recruitment which may impair rehabilitation and delay the return to activity. Knee angular displacement and velocity as well as lower limb EMG were measured in the period 250 milliseconds pre initial contact to 250 milliseconds post initial contact during a single leg drop jump in 8 healthy subjects before and after a simulated knee joint effusion of 60 millilitres. Repeated measures ANOVA and post hoc testing revealed no statistically significant differences in pre and post effusion in knee kinematic or lower limb EMG measures undertaken. A simulated knee effusion did not result in significant alterations to knee joint mechanics or lower limb muscle activation patterns during a single leg drop landing. The mechanism by which an effusion affects motor control during functional and dynamic weight bearing tasks warrants further investigation

    Light-cone gauge Hamiltonian for AdS_4 x CP^3 superstring

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    It is developed the phase-space formulation for the Type IIA superstring on the AdS_4 x CP^3 background in the kappa-symmetry light-cone gauge for which the light-like directions are taken from the D=3 Minkowski boundary of AdS_4. After fixing bosonic light-cone gauge the superstring Hamiltonian is expressed as a function of the transverse physical variables and in the quadratic approximation corresponds to the light-cone gauge-fixed IIA superstring in flat space.Comment: 12 pages, LaTeX; v2 minor improvements of the text, misprints corrected, reference added; v3: missing terms in Eqs.(8),(53) and (56) adde

    Fatigue induced changes to kinematic and kinetic gait parameters following six minutes of walking in people with Multiple Sclerosis

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Disability and Rehabilitation on 20 May 2015, available online: http://www.tandfonline.com/doi/abs/10.3109/09638288.2015.1047969Purpose: The aim of this study was to examine the effect of 6 min of walking on fatigue, exertion and spatiotemporal, kinematic and kinetic gait parameters in people with multiple sclerosis (MS). Methods: Thirty-four people with MS with moderate levels of disability completed measures of fatigue, exertion and instrumented gait analysis before and after 6-min trials of rest and walking (using a modified 6-min walk test, m6MWT). Ten age- and gender-matched healthy controls completed analysis before and after the m6MWT. Results: The MS group had a significant increase in self-reported fatigue following the m6MWT; however, there was no effect on spatiotemporal gait parameters. During stance on the more affected side ankle dorsiflexion at initial contact decreased, while knee and hip flexor moments and hip power absorption increased. On the less affected side ankle and knee power absorption, and hip extensor moment all increased. Healthy controls showed increases in joint kinetics likely due to increased walking speeds following m6MWT. Conclusion: For people with MS, ankle dorsiflexion angle reduces at initial contact following walking induced fatigue, while increased power absorption at the hip, knee and ankle indicate gait inefficiencies that may contribute to higher levels of fatigue and exertion. Implications for Rehabilitation The modified 6-min walk test (m6MWT) leads to significant increases in self-reported fatigue and exertion in people with MS. Following the m6MWT, there is significantly reduced ankle dorsiflexion angle at initial contact in the more affected leg in people with MS. This reveals an important walking-induced kinematic change that should be the target of future orthotic and strengthening interventions. In people with MS, increased power absorption primarily during the stance phase of gait following the m6MWT reveals important walking-induced muscle weakness that should also be monitored in future strengthening and gait retraining interventions

    Integrating multiple genome annotation databases improves the interpretation of microarray gene expression data

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    <p>Abstract</p> <p>Background</p> <p>The Affymetrix GeneChip is a widely used gene expression profiling platform. Since the chips were originally designed, the genome databases and gene definitions have been considerably updated. Thus, more accurate interpretation of microarray data requires parallel updating of the specificity of GeneChip probes. We propose a new probe remapping protocol, using the zebrafish GeneChips as an example, by removing nonspecific probes, and grouping the probes into transcript level probe sets using an integrated zebrafish genome annotation. This genome annotation is based on combining transcript information from multiple databases. This new remapping protocol, especially the new genome annotation, is shown here to be an important factor in improving the interpretation of gene expression microarray data.</p> <p>Results</p> <p>Transcript data from the RefSeq, GenBank and Ensembl databases were downloaded from the UCSC genome browser, and integrated to generate a combined zebrafish genome annotation. Affymetrix probes were filtered and remapped according to the new annotation. The influence of transcript collection and gene definition methods was tested using two microarray data sets. Compared to remapping using a single database, this new remapping protocol results in up to 20% more probes being retained in the remapping, leading to approximately 1,000 more genes being detected. The differentially expressed gene lists are consequently increased by up to 30%. We are also able to detect up to three times more alternative splicing events. A small number of the bioinformatics predictions were confirmed using real-time PCR validation.</p> <p>Conclusions</p> <p>By combining gene definitions from multiple databases, it is possible to greatly increase the numbers of genes and splice variants that can be detected in microarray gene expression experiments.</p

    Universal school meals and associations with student participation, attendance, academic performance, diet quality, food security, and Body Mass Index: A systematic review

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    The school environment plays an important role in children\u27s diets and overall health, and policies for universal free school meals have the potential to contribute to positive child health outcomes. This systematic review evaluates studies examining the association between universal free school meals and students\u27 school meal participation rates, diets, attendance, academic performance, and Body Mass Index (BMI), as well as school finances. The search was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA). A search for studies published in economically developed countries published through December 2020 was performed in PubMed, Education Resources Information Center (ERIC), Thomson Reuters\u27 Web of Science, and Academic Search Ultimate, followed by examining the references in the resultant literature. A total of 47 studies were identified and the Newcastle-Ottawa Scale (NOS) was applied to assess bias. Nearly all studies examining universal free school meals found positive associations with school meal participation. Most studies examining universal free school meals that included free lunch found positive associations with diet quality, food security, and academic performance; however, the findings of studies examining only universal free breakfast were mixed. Research findings were similarly mixed when examining attendance as an outcome. Concerns about adverse outcomes on student BMI were not supported by the literature; in fact, several studies detected a potentially protective effect of universal free school meals on BMI. Research examining the impact of universal free meals on school finances was limited, but suggest that lower-income school districts in the U.S. may have positive financial outcomes from participation in universal free school meal provisions. Additionally, providing free meals to students may be associated with improved household incomes, particularly among lower-income families with children. Further research is needed to examine the financial implications of universal free meals for both school districts and families. Overall, universal free school meals may have multiple benefits for students and countries should consider universal free school meal provisions with strong nutrition guidelines. (PROSPERO registration: CRD42020221782)

    Alpha oscillatory activity during attentional control in children with Autism Spectrum Disorder (ASD), Attention-Deficit/Hyperactivity Disorder (ADHD), and ASD+ADHD

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    BACKGROUND: Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) share impairments in top-down and bottom-up modulation of attention. However, it is not yet well understood if co-occurrence of ASD and ADHD reflects a distinct or additive profile of attention deficits. We aimed to characterise alpha oscillatory activity (stimulus-locked alpha desynchronisation and prestimulus alpha) as an index of integration of top-down and bottom-up attentional processes in ASD and ADHD. METHODS: Children with ASD, ADHD, comorbid ASD+ADHD, and typically-developing children completed a fixed-choice reaction-time task (‘Fast task’) while neurophysiological activity was recorded. Outcome measures were derived from source-decomposed neurophysiological data. Main measures of interest were prestimulus alpha power and alpha desynchronisation (difference between poststimulus and prestimulus alpha). Poststimulus activity linked to attention allocation (P1, P3), attentional control (N2), and cognitive control (theta synchronisation, 100–600 ms) was also examined. ANOVA was used to test differences across diagnostics groups on these measures. Spearman’s correlations were used to investigate the relationship between attentional control processes (alpha oscillations), central executive functions (theta synchronisation), early visual processing (P1), and behavioural performance. RESULTS: Children with ADHD (ADHD and ASD+ADHD) showed attenuated alpha desynchronisation, indicating poor integration of top-down and bottom-up attentional processes. Children with ADHD showed reduced N2 and P3 amplitudes, while children with ASD (ASD and ASD+ADHD) showed greater N2 amplitude, indicating atypical attentional control and attention allocation across ASD and ADHD. In the ASD group, prestimulus alpha and theta synchronisation were negatively correlated, and alpha desynchronisation and theta synchronisation were positively correlated, suggesting an atypical association between attentional control processes and executive functions. CONCLUSIONS: ASD and ADHD are associated with disorder-specific impairments, while children with ASD+ADHD overall presented an additive profile with attentional deficits of both disorders. Importantly, these findings may inform the improvement of transdiagnostic procedures and optimisation of personalised intervention approaches
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