683 research outputs found
Self-confirming Inflation Persistence
In this paper we simulate a central bank subject to the misperception that prices are indexed to past inflation in periods when firms are unable to re-optimise. It thinks, in other words, that inflation is intrinsically persistent. The central bank sets monetary policy optimally subject to this belief. The central bank updates its beliefs about inÂŹdexation using a constant gain learning scheme. The data generated by such policy lead to beliefs about inflation persistence being effectively self-confirming in a wide variety of setttings. These results offer a tentative answer to why it appears that inflation is persistent at some times and in some countries, and at others not. The answer is that policymakers sometimes believe inflation to be persistent, and sometimes do not.
Unitarity Cuts: NLO Six-Gluon Amplitudes in QCD
We report on a technique for evaluating finite unitarity cut for one-loop
amplitudes in gauge theories, and discuss its application to the
cut-constructible part of six-gluon amplitude in QCD.Comment: talk given at Loops & Legs 2006, April 23-28, Eisenach (Germany
Improving the accuracy of estimates of animal path and travel distance using GPS drift-corrected dead reckoning
Route taken and distance travelled are important parameters for studies of animal locomotion. They are often measured using a collar equipped with GPS. Collar weight restrictions limit battery size, which leads to a compromise between collar operating life and GPS fix rate. In studies that rely on linear interpolation between intermittent GPS fixes, path tortuosity will often lead to inaccurate path and distance travelled estimates. Here, we investigate whether GPSâcorrected dead reckoning can improve the accuracy of localization and distance travelled estimates while maximizing collar operating life. Customâbuilt tracking collars were deployed on nine freely exercising domestic dogs to collect high fix rate GPS data. Simulations were carried out to measure the extent to which combining accelerometerâbased speed and magnetometer heading estimates (dead reckoning) with low fix rate GPS drift correction could improve the accuracy of path and distance travelled estimates. In our study, median 2âdimensional rootâmeanâsquared (2DâRMS) position error was between 158 and 463Â m (median path length 16.43Â km) and distance travelled was underestimated by between 30% and 64% when a GPS position fix was taken every 5Â min. Dead reckoning with GPS drift correction (1 GPS fix every 5Â min) reduced 2DâRMS position error to between 15 and 38Â m and distance travelled to between an underestimation of 2% and an overestimation of 5%. Achieving this accuracy from GPS alone would require approximately 12 fixes every minute and result in a battery life of approximately 11Â days; dead reckoning reduces the number of fixes required, enabling a collar life of approximately 10Â months. Our results are generally applicable to GPSâbased tracking studies of quadrupedal animals and could be applied to studies of energetics, behavioral ecology, and locomotion. This lowâcost approach overcomes the limitation of low fix rate GPS and enables the longâterm deployment of lightweight GPS collars
Abiotic Factors Contributing to the Survival of Three Tick Species in Southeastern Virginia, \u3ci\u3eAmblyomma Americanum\u3c/i\u3e (Lone Star Tick), \u3ci\u3eDermacentor Variabilis\u3c/i\u3e (American Dog Tick), and \u3ci\u3eAmblyomma Maculatum\u3c/i\u3e (Gulf Coast Tick)
Amblyomma americanum, Amblyomma maculatum, and Dermacentor variabilis are hard-bodied ticks in the Hampton Roads area of southeastern Virginia. This study consisted of two field projects focused on these tick species. To estimate the off-host survival of local tick species, a capture-mark-recapture (CMR) study was performed. An environmental survival study was performed to quantify the ability of these three tick species to survive in situ. Four field sites were used in the Hampton Roads region covering a variety of habitat types and vegetation; specifically two drier, upland field sites and two flood-prone sites. CMR was conducted from May through September at two field sites in 2014 (one dry, one wet), then all four sites in 2015. The environmental survival study was conducted May through September of 2015 at all four sites.
CMR ticks were captured on flags, marked with fingernail polish, and returned to the location of capture. Amblyomma americanum was the dominant species collected (95% in 2014, 87% in 2015) when compared to the other tick species collected: D. variabilis, A. maculatum, and Ixodes spp. In 2014, 1 D. variabilis female and 32 A. americanum ticks were recaptured. One A. americanum nymph and 1 D. variabilis female were recaptured an additional time. For A. americanum, the average time-to-recapture was 30 days with a maximum of 71 and a minimum of 8 days. Only 1 male A. americanum tick was recaptured in 2015, 27days post initial marking.
In the environmental survival study, A. americanum, D. variabilis, and A. maculatum ticks were placed inside environmental containers in situ over four months. The containers were checked at fixed intervals to quantify survival. A Cox Regression survival analysis indicated there is a significant difference in survival between species across all field sites. There is a 50.5-times higher risk of mortality for A. maculatum compared to A. americanum, a 4.3-times higher risk of mortality for A. maculatum compared to D. variabilis, and an 11.9-times higher risk of mortality for D. variabilis compared to A. americanum. There is also significantly higher mortality in field sites prone to flooding than in drier, upland field sites
To what extent is the regulation of sport effective in terms of financial management of clubs? An evaluation of corporate and financial governance, in the context of failing football clubs and salary cap clauses.
The 2018 events surrounding the financial fair play dispute that arose between Manchester City Football Club and UEFA provides the background for this article. Much case law and literature has focused upon professional sport financial issues, including salary caps and financial fair play. Three specific legal issues are discussed here, however, framed by three core questions, and using European football as the primary example: do current professional sports financial management regulations (Financial Fair Play, or hereinafter FFP) provide sufficient deterrence against club financial misconduct? Do football clubsâ corporate governance principles differ to those applicable to other corporate environments? Are salary caps a viable football financial management option? The article will then argue the need for reforms to current football FFP approaches. The opening section offers definitions and explanatory notes on the relevant governance in sport, including what constitutes âfinancial fair play.â Section two looks to the Manchester City Football Club - UEFA dispute, to offer analysis of the current financial regulations - and the long-term football governance consequences â to suggest that FFP has not (yet) translated into improvements for financial sustainability. Section three offer suggestions for reform, including the proposition that a well-constructed salary cap system would perhaps prevent future disputes. The conclusion further argues that an appropriate salary cap model provides for surer, more transparent financial governance than the current FFP system
Supersymmetric Ward Identities and NMHV Amplitudes involving Gluinos
We show how Supersymmetric Ward identities can be used to obtain amplitudes
involving gluinos or adjoint scalars from purely gluonic amplitudes. We obtain
results for all one-loop six-point NMHV amplitudes in \NeqFour Super
Yang-Mills theory which involve two gluinos or two scalar particles. More
general cases are also discussed.Comment: 32 pages, minor typos fixed; one reference adde
A comparison of saccadic and blink suppression in normal observers
Recent research suggests that blink and saccadic suppression are produced by the same mechanism (Volkmann, 1986; Uchikawa & Sato, 1995; Ridder & Tomlinson, 1993, 1995). These studies demonstrated that blink and saccadic suppression have the same effect on various visual functions. However, none of these studies made a comparison of blink and saccadic suppression in the same individual. The purpose of this study was to compare the effects of blink and saccadic suppression on contrast sensitivity functions in the same subject. The effect of saccadic suppression on the contrast sensitivity function in three normal observers was determined. Employing a two-alternative, forced-choice technique, thresholds were measured for seven spatial frequencies. At each spatial frequency, the threshold was determined immediately following detection of a voluntary saccade. The magnitude of suppression was taken as the log ratio of the contrast sensitivities obtained while foveating the stimulus and those obtained during saccades. The magnitude of saccadic suppression was found to increase as the saccade amplitude increased and to be spatial-frequency dependent. Low spatial frequencies were suppressed more than high spatial frequencies. The blink suppression data have been measured previously (Ridder & Tomlinson, 1993). Saccadic and blink suppression were qualitatively similar. A vertical shift of the data brought the saccadic and blink suppression data into register. These results suggest that blink and saccadic suppression are produced by the same or similar mechanisms
Exploiting Twistor Techniques for One-loop QCD Amplitudes
In this talk we describe the recursive Approach to One-loop QCD Matrix
Elements.Comment: Talk presented by David C. Dunbar at Loop and Legs 2006, 5 page
Recursive Approach to One-loop QCD Matrix Elements
We describe the recursive Approach to One-loop QCD Matrix Elements.Comment: 6 pages, to appear in the proceedings of the 7th International
Symposium on Radiative Corrections: Application of Quantum Field Theory to
Phenomenology (RADCOR 2005), Japan, 2-7 Oct 200
EFFECTS OF BALANCING HAMSTRING AND QUADRICEPS MUSCLE TORQUE ON RUNNING TECHNIQUE
It has been suggested that balancing the isokinetic strength of quadriceps (Q) and hamstring (H) muscles can reduce hamstring injuries during running (Croisier et al 2008). The efficacy of this type of intervention has been previously explored. To further the knowledge of the H: Q relationship we have examined the interventionâs affect on running technique as presented here
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