56,959 research outputs found
Uniqueness and Logical Disagreement
This paper discusses the uniqueness thesis, a core thesis in the epistemology of disagreement. After presenting uniqueness and clarifying relevant terms, a novel counterexample to the thesis will be introduced. This counterexample involves logical disagreement. Several objections to the counterexample are then considered, and it is argued that the best responses to the counterexample all undermine the initial motivation for uniqueness
An informal analysis of flight control tasks
Issues important in rotorcraft flight control are discussed. A perceptual description is suggested of what is believed to be the major issues in flight control. When the task is considered of a pilot controlling a helicopter in flight, the task is decomposed in several subtasks. These subtasks include: (1) the control of altitude, (2) the control of speed, (3) the control of heading, (4) the control of orientation, (5) the control of flight over obstacles, and (6) the control of flight to specified positions in the world. The first four subtasks can be considered to be primary control tasks as they are not dependent on any other subtasks. However, the latter two subtasks can be considered hierarchical tasks as they are dependent on other subtasks. For example, the task of flight control over obstacles can be decomposed as a task requiring the control of speed, altitude, and heading. Thus, incorrect control of altitude should result in poor control of flight over an obstacle
Increments of Uncorrelated Time Series Can Be Predicted With a Universal 75% Probability of Success
We present a simple and general result that the sign of the variations or
increments of uncorrelated times series are predictable with a remarkably high
success probability of 75% for symmetric sign distributions. The origin of this
paradoxical result is explained in details. We also present some tests on
synthetic, financial and global temperature time series.Comment: 8 pages, 3 figure
DNA extraction from museum specimens of parasitic Hymenoptera.
At the same time that molecular researchers are improving techniques to extract DNA from museum specimens, this increased demand for access to museum specimens has created tension between the need to preserve specimens for maintaining collections and morphological research and the desire to conduct molecular analyses. To address these concerns, we examined the suitability of non-invasive DNA extraction techniques on three species of parasitic Hymenoptera (Braconidae), and test the effects of body size (parasitoid species), age (time since collection), and DNA concentration from each extract on the probability of amplifying meaningful fragments of two commonly used genetic loci. We found that age was a significant factor for determining the probability of success for sequencing both 28S and COI fragments. While the size of the braconid parasitoids significantly affected the total amount of extracted DNA, neither size nor DNA concentration were significant factors for the amplification of either gene region. We also tested several primer combinations of various lengths, but were unable to amplify fragments longer than ~150 base pairs. These short fragments of 28S and COI were however sufficient for species identification, and for the discovery of within species genetic variation
Scaling with respect to disorder in time-to-failure
We revisit a simple dynamical model of rupture in random media with
long-range elasticity to test whether rupture can be seen as a first-order or a
critical transition. We find a clear scaling of the macroscopic modulus as a
function of time-to-rupture and of the amplitude of the disorder, which allows
us to collapse neatly the numerical simulations over more than five decades in
time and more than one decade in disorder amplitude onto a single master curve.
We thus conclude that, at least in this model, dynamical rupture in systems
with long-range elasticity is a genuine critical phenomenon occurring as soon
as the disorder is non-vanishing.Comment: 13 pages, 2 figures, submitted to J.Phys.I (France
Food and nutrition security in Timor-Leste
This report is a literature review on Food and Nutrition Security in Timor-Leste based on data from surveys conducted by the Timor-Leste National Statistics Directorate, as well as from national and international organizations working in Timor-Leste. This review was supported by the Australian Centre for International Agricultural Research (ACIAR)-funded project “Strategy for Investment in Fisheries in East Timor”. This report describes the current food and nutrition situation in Timor-Leste for the purpose of planning and implementing interventions aimed at improving food and nutrition security, especially within aquatic agricultural systems. The potential role of aquaculture in improving food and nutrition security is considered, with reference to the recently endorsed Timor-Leste National Aquaculture Development Strategy (2012-2030) developed by the National Directorate of Fisheries and Agriculture, Ministry of Agriculture and Fisheries
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