1,969 research outputs found
Listening to the Promise of a Better You: Considering the Instructional Record
While this article makes explicit connections with forms such as karaoke, it also offers insight into other areas of sonic instruction such as dance, exercise and gaming. More important, it begins to develop an explicit theoretical foothold on questions of record production and reception where the listener is conceived in both the form of the recording and its accompanying narratives by focusing on how many of these instructional objects are designed around specific questions of record production and their accompanying paratextual elements
Suppression of displacement in severely slowed saccades
Severely slowed saccades in <I>spinocerebellar ataxia</I> have previously been shown to be at least partially closed-loop in nature: their long duration means that they can be modified in-flight in response to intrasaccadic target movements. In this study, a woman with these pathologically slowed saccades could modify them in-flight in response to target movements, even when saccadic suppression of displacement prevented conscious awareness of those movements. Thus saccadic suppression of displacement is not complete, in that it provides perceptual information that is sub-threshold to consciousness but which can still be effectively utilised by the oculomotor system
Spiral mechanisms are required to account for summation of complex motion components
AbstractStimuli from one family of complex motions are defined by their spiral pitch, where cardinal axes represent signed expansion and rotation. Intermediate spirals are represented by intermediate pitches. It is well established that vision contains mechanisms that sum over space and direction to detect these stimuli (Morrone et al., Nature 376 (1995) 507) and one possibility is that four cardinal mechanisms encode the entire family. We extended earlier work (Meese & Harris, Vision Research 41 (2001) 1901) using subthreshold summation of random dot kinematograms and a two-interval forced choice technique to investigate this possibility. In our main experiments, the spiral pitch of one component was fixed and that of another was varied in steps of 15° relative to the first. Regardless of whether the fixed component was aligned with cardinal axes or an intermediate spiral, summation to-coherence-threshold between the two components declined as a function of their difference in spiral pitch. Similar experiments showed that none of the following were critical design features or stimulus parameters for our results: superposition of signal dots, limited life-time dots, the presence of speed gradients, stimulus size or the number of dots. A simplex algorithm was used to fit models containing mechanisms spaced at a pitch of either 90° (cardinal model) or 45° (cardinal+model) and combined using a fourth-root summation rule. For both models, direction half-bandwidth was equated for all mechanisms and was the only free parameter. Only the cardinal+model could account for the full set of results. We conclude that the detection of complex motion in human vision requires both cardinal and spiral mechanisms with a half-bandwidth of approximately 46°
Network Inoculation: Heteroclinics and phase transitions in an epidemic model
In epidemiological modelling, dynamics on networks, and in particular
adaptive and heterogeneous networks have recently received much interest. Here
we present a detailed analysis of a previously proposed model that combines
heterogeneity in the individuals with adaptive rewiring of the network
structure in response to a disease. We show that in this model qualitative
changes in the dynamics occur in two phase transitions. In a macroscopic
description one of these corresponds to a local bifurcation whereas the other
one corresponds to a non-local heteroclinic bifurcation. This model thus
provides a rare example of a system where a phase transition is caused by a
non-local bifurcation, while both micro- and macro-level dynamics are
accessible to mathematical analysis. The bifurcation points mark the onset of a
behaviour that we call network inoculation. In the respective parameter region
exposure of the system to a pathogen will lead to an outbreak that collapses,
but leaves the network in a configuration where the disease cannot reinvade,
despite every agent returning to the susceptible class. We argue that this
behaviour and the associated phase transitions can be expected to occur in a
wide class of models of sufficient complexity.Comment: 26 pages, 11 figure
The Link between General Relativity and Shape Dynamics
We show that one can construct two equivalent gauge theories from a linking
theory and give a general construction principle for linking theories which we
use to construct a linking theory that proves the equivalence of General
Relativity and Shape Dynamics, a theory with fixed foliation but spatial
conformal invariance. This streamlines the rather complicated construction of
this equivalence performed previously. We use this streamlined argument to
extend the result to General Relativity with asymptotically flat boundary
conditions. The improved understanding of linking theories naturally leads to
the Lagrangian formulation of Shape Dynamics, which allows us to partially
relate the degrees of freedom.Comment: 19 pages, LaTeX, no figure
The impact of increased antiterrorism/force protection requirements on ships operations fundingh[electronic resource]
Since the terrorist attack on USS COLE (DDG 67) and more recently the attacks on New York City and the Pentagon, Antiterrorism/Force Protection (AT/FP) requirements have increased dramatically throughout the Department of Defense (DOD). As these requirements escalate in scope and number, so do the costs of meeting them. In the Navy, ships are bearing a portion of these costs out of their operations funding. Type Commanders (TYCOMs) fund the operations of all ships and squadrons under their command. In order to have a firm grasp on how these new AT/FP requirements will affect them financially, they must be able to forecast the costs related to them and make appropriate adjustments to their existing ships operations funding model. Acquiring a better grasp on the fiscal impacts of these new requirements will allow Type Commanders to more effectively budget for them in the future. This thesis provides a shipboard AT/FP cost estimation model to aid in forecasting costs associated with these activities.http://archive.org/details/theimpactofincre109456102US Navy (USN) author
Examining Behaviors Using Respondents’ Cell Phones and a Burst Design: Drinking and Activities Across the First Year of College Among Transitioning Freshmen
Purpose
The study of developmental and life-course changes of an individual necessitates longitudinal data. Traditional panel designs, however, that tend to collect data annually or less often may not reflect change experienced by individuals especially in periods of transition. The first year of college likely is one such period in which change takes place at a rapid pace. Methods
We followed approximately 100 residential college students across their freshman year. In an attempt to capture the changes taking place in friendships, activities, and alcohol use, we used a traditional panel design in which we administered structured surveys at the beginning, middle, and end of the academic year. We extended this design by employing a “burst” design to capture data frequently and in real time. Respondents were sent a text message with a link to a short survey asking about their activities. They received our text across 3-day intervals, multiple times within each day, approximately every month of the school year. Results
In this paper, we discuss our approach and demonstrate the utility of burst designs. We show how such data collection schemes can complement more traditional designs by comparing information collected with the two approaches to show what could have been lost had we relied only on surveys at three time points. Conclusions
The developmental transitions of college students occurred at a faster rate than our panel design could capture. Our findings suggest that researchers interested in a wide variety of transitions should employ burst designs alongside other traditional data collection techniques
Einstein gravity as a 3D conformally invariant theory
We give an alternative description of the physical content of general
relativity that does not require a Lorentz invariant spacetime. Instead, we
find that gravity admits a dual description in terms of a theory where local
size is irrelevant. The dual theory is invariant under foliation preserving
3-diffeomorphisms and 3D conformal transformations that preserve the 3-volume
(for the spatially compact case). Locally, this symmetry is identical to that
of Horava-Lifshitz gravity in the high energy limit but our theory is
equivalent to Einstein gravity. Specifically, we find that the solutions of
general relativity, in a gauge where the spatial hypersurfaces have constant
mean extrinsic curvature, can be mapped to solutions of a particular gauge
fixing of the dual theory. Moreover, this duality is not accidental. We provide
a general geometric picture for our procedure that allows us to trade foliation
invariance for conformal invariance. The dual theory provides a new proposal
for the theory space of quantum gravity.Comment: 27 pages. Published version (minor changes and corrections
Measuring exposure to bullying and harassment in health professional students in a clinical workplace environment : Evaluating the psychometric properties of the clinical workplace learning NAQ-R scale
Acknowledgments: The authors would like to thank all of the Associate Deans of Medical Education for Otago Medical School who assisted with the data collection for this questionnaire, as well as Faculty in The School of Nursing at Otago Polytechnic. We would also like to thank Dr Ella Iosua and Michel de Lange for their initial advice on the analysis of this paper. We would also like to thank the students for their time and effort in completing this questionnaire.Peer reviewedPostprin
Close kinship within multiple-genotype malaria parasite infections
Malaria infections containing multiple parasite genotypes are ubiquitous in nature, and play a central role in models of recombination, intra-host dynamics, virulence, sex ratio, immunity and drug resistance evolution in Plasmodium. While these multiple infections (MIs) are often assumed to result from superinfection (bites from multiple infected mosquitoes), we know remarkably little about their composition or generation. We isolated 336 parasite clones from eight patients from Malawi (high transmission) and six from Thailand (low transmission) by dilution cloning. These were genotyped using 384 single-nucleotide polymorphisms, revealing 22 independent haplotypes in Malawi (2–6 per MI) and 15 in Thailand (2–5 per MI). Surprisingly, all six patients from Thailand and six of eight from Malawi contained related haplotypes, and haplotypes were more similar within- than between-infections. These results argue against a simple superinfection model. Instead, the observed kinship patterns may be explained by inoculation of multiple related haploid sporozoites from single mosquito bites, by immune suppression of parasite subpopulations within infections, and serial transmission of related parasites between people. That relatedness is maintained in endemic areas in the face of repeated bites from infected mosquitoes has profound implications for understanding malaria transmission, immunity and intra-host dynamics of co-infecting parasite genotypes
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