5,912 research outputs found
Signatures of Dynamical Tunneling in the Wave function of a Soft-Walled Open Microwave Billiard
Evidence for dynamical tunneling is observed in studies of the transmission,
and wave functions, of a soft-walled microwave cavity resonator. In contrast to
previous work, we identify the conditions for dynamical tunneling by monitoring
the evolution of the wave function phase as a function of energy, which allows
us to detect the tunneling process even under conditions where its expected
level splitting remains irresolvable.Comment: 5 pages, 5 figure
An Investigation of Coach Behaviors, Goal Motives, and Implementation Intentions as Predictors of Well-Being in Sport
The present study aimed to expand upon Smith, Ntoumanis, and Duda’s (2007) research by investigating the influence of coach behaviors and implementation intentions on goal striving in sport. Structural equation modeling analysis with a sample of 108 athletes revealed coach behaviors as predictors of goal motives, which in turn predicted psychological well-being after 8 weeks. Supplementary regression analyses showed no interaction between autonomous goal motives and implementation intentions; however, a synergistic effect was identified for controlled goal motives such that controlled motives furnished with implementation intentions resulted in lower well-being than controlled motives alone. In further analyses, the motives underlying an implementation intention were found to mediate the paths from goal motives to well-being. The findings are discussed in terms of the roles played by goal motives, implementation intentions, and implementation intention motives during goal striving
Directional asymmetries reveal a universal bias in adult vowel perception
published online 21 April 2017Research on cross-language vowel perception in both infants and adults has shown that for many
vowel contrasts, discrimination is easier when the same pair of vowels is presented in one direction
compared to the reverse direction. According to one account, these directional asymmetries
reflect a universal bias favoring “focal” vowels (i.e., vowels whose adjacent formants are close
in frequency, which concentrates acoustic energy into a narrower spectral region). An alternative,
but not mutually exclusive, account is that such effects reflect an experience-dependent
bias favoring prototypical instances of native-language vowel categories. To disentangle the
effects of focalization and prototypicality, the authors first identified a certain location in
phonetic space where vowels were consistently categorized as /u/ by both Canadian-English and
Canadian-French listeners, but that nevertheless varied in their stimulus goodness (i.e., the best
Canadian-French /u/ exemplars were more focal compared to the best Canadian-English /u/
exemplars). In subsequent AX discrimination tests, both Canadian-English and Canadian-French
listeners performed better at discriminating changes from less to more focal /u/’s compared to
the reverse, regardless of variation in prototypicality. These findings demonstrate a universal
bias favoring vowels with greater formant convergence that operates independently of biases
related to language-specific prototype categorization.This research was supported by NSERC Discovery
Grant No. 105397 to L.P. and NSERC Discovery Grant No.
312395 to L.M
NS1 Specific CD8(+) T-Cells with Effector Function and TRBV11 Dominance in a Patient with Parvovirus B19 Associated Inflammatory Cardiomyopathy
Background: Parvovirus B19 (B19V) is the most commonly detected virus in endomyocardial biopsies (EMBs) from patients with inflammatory cardiomyopathy (DCMi). Despite the importance of T-cells in antiviral defense, little is known about the role of B19V specific T-cells in this entity.
Methodology and Principal Findings: An exceptionally high B19V viral load in EMBs (115,091 viral copies/mg nucleic acids), peripheral blood mononuclear cells (PBMCs) and serum was measured in a DCMi patient at initial presentation, suggesting B19V viremia. The B19V viral load in EMBs had decreased substantially 6 and 12 months afterwards, and was not traceable in PBMCs and the serum at these times. Using pools of overlapping peptides spanning the whole B19V proteome, strong CD8(+) T-cell responses were elicited to the 10-amico-acid peptides SALKLAIYKA (19.7% of all CD8(+) cells) and QSALKLAIYK (10%) and additional weaker responses to GLCPHCINVG (0.71%) and LLHTDFEQVM (0.06%). Real-time RT-PCR of IFN gamma secretion-assay-enriched T-cells responding to the peptides, SALKLAIYKA and GLCPHCINVG, revealed a disproportionately high T-cell receptor Vbeta (TRBV) 11 expression in this population. Furthermore, dominant expression of type-1 (IFN gamma, IL2, IL27 and Tbet) and of cytotoxic T-cell markers (Perforin and Granzyme B) was found, whereas gene expression indicating type-2 (IL4, GATA3) and regulatory T-cells (FoxP3) was low.
Conclusions: Our results indicate that B19V Ag-specific CD8(+) T-cells with effector function are involved in B19V associated DCMi. In particular, a dominant role of TRBV11 and type-1/CTL effector cells in the T-cell mediated antiviral immune response is suggested. The persistence of B19V in the endomyocardium is a likely antigen source for the maintenance of CD8(+) T-cell responses to the identified epitopes
An efficient Fredholm method for calculation of highly excited states of billiards
A numerically efficient Fredholm formulation of the billiard problem is
presented. The standard solution in the framework of the boundary integral
method in terms of a search for roots of a secular determinant is reviewed
first. We next reformulate the singularity condition in terms of a flow in the
space of an auxiliary one-parameter family of eigenproblems and argue that the
eigenvalues and eigenfunctions are analytic functions within a certain domain.
Based on this analytic behavior we present a numerical algorithm to compute a
range of billiard eigenvalues and associated eigenvectors by only two
diagonalizations.Comment: 15 pages, 10 figures; included systematic study of accuracy with 2
new figures, movie to Fig. 4,
http://www.quantumchaos.de/Media/0703030media.av
Willing and able: action-state orientation and the relation between procedural justice and employee cooperation
Existing justice theory explains why fair procedures motivate employees to adopt cooperative goals, but it fails to explain how employees strive towards these goals. We study self-regulatory abilities that underlie goal striving; abilities that should thus affect employees’ display of cooperative behavior in response to procedural justice. Building on action control theory, we argue that employees who display effective self-regulatory strategies (action oriented employees) display relatively strong cooperative behavioral responses to fair procedures. A multisource field study and a laboratory experiment support this prediction. A subsequent experiment addresses the process underlying this effect by explicitly showing that action orientation facilitates attainment of the cooperative goals that people adopt in response to fair procedures, thus facilitating the display of actual cooperative behavior. This goal striving approach better integrates research on the relationship between procedural justice and employee cooperation in the self-regulation and the work motivation literature. It also offers organizations a new perspective on making procedural justice effective in stimulating employee cooperation by suggesting factors that help employees reach their adopted goals
Mobility Edge in Aperiodic Kronig-Penney Potentials with Correlated Disorder: Perturbative Approach
It is shown that a non-periodic Kronig-Penney model exhibits mobility edges
if the positions of the scatterers are correlated at long distances. An
analytical expression for the energy-dependent localization length is derived
for weak disorder in terms of the real-space correlators defining the
structural disorder in these systems. We also present an algorithm to construct
a non-periodic but correlated sequence exhibiting desired mobility edges. This
result could be used to construct window filters in electronic, acoustic, or
photonic non-periodic structures.Comment: RevTex, 4 pages including 2 Postscript figure
Playing relativistic billiards beyond graphene
The possibility of using hexagonal structures in general and graphene in
particular to emulate the Dirac equation is the basis of our considerations. We
show that Dirac oscillators with or without restmass can be emulated by
distorting a tight binding model on a hexagonal structure. In a quest to make a
toy model for such relativistic equations we first show that a hexagonal
lattice of attractive potential wells would be a good candidate. First we
consider the corresponding one-dimensional model giving rise to a
one-dimensional Dirac oscillator, and then construct explicitly the
deformations needed in the two-dimensional case. Finally we discuss, how such a
model can be implemented as an electromagnetic billiard using arrays of
dielectric resonators between two conducting plates that ensure evanescent
modes outside the resonators for transversal electric modes, and describe an
appropriate experimental setup.Comment: 23 pages, 8 figures. Submitted to NJ
Mechanisms of nitrogen transfer in a model clover-ryegrass pasture: a 15N-tracer approach
Purpose
Nitrogen (N) transfer from white clover (Trifolium repens cv.) to ryegrass (Lolium perenne cv.) has the potential to meet ryegrass N requirements. This study aimed to quantify N transfer in a mixed pasture and investigate the influence of the microbial community and land management on N transfer.
Methods
Split root 15N-labelling of clover quantified N transfer to ryegrass via exudation, microbial assimilation, decomposition, defoliation and soil biota. Incorporation into the microbial protein pool was determined using compound-specific 15N-stable isotope probing approaches.
Results
N transfer to ryegrass and soil microbial protein in the model system was relatively smallwith one-third arising from root exudation. N transfer to ryegrass increased with no microbial competition but soil microbes also increased N transfer via shoot decomposition. Addition of mycorrhizal fungi did not alter N transfer, due to the source-sink nature of this pathway, whilst weevil grazing on roots decreased
microbial N transfer. N transfer was bidirectional, and
comparable on a short-term scale.
Conclusions
N transfer was low in a model young pasture established from soil from a permanent grassland with long-term N fertilisation. Root exudation and decomposition were major N transfer pathways. N transfer was influenced by soil biota (weevils, mycorrhizae) and land management (e.g. grazing). Previous land management and the role of the microbial community in N transfer must be considered when determining the potential for N transfer to ryegras
Comparison of mesospheric winds from a high-altitude meteorological analysis system and meteor radar observations during the boreal winters of 2009–2010 and 2012–2013
We present a study of horizontal winds in the mesosphere and lower thermosphere (MLT) during the boreal winters of 2009–2010 and 2012–2013 produced with a new high-altitude numerical weather prediction (NWP) system. This system is based on a modified version of the Navy Global Environmental Model (NAVGEM) with an extended vertical domain up to ∼116 km altitude coupled with a hybrid four-dimensional variational (4DVAR) data assimilation system that assimilates both standard operational meteorological observations in the troposphere and satellite-based observations of temperature, ozone and water vapor in the stratosphere and mesosphere. NAVGEM-based MLT analyzed winds are validated using independent meteor radar wind observations from nine different sites ranging from 69°N–67°S latitude. Time-averaged NAVGEM zonal and meridional wind profiles between 75 and 95 km altitude show good qualitative and quantitative agreement with corresponding meteor radar wind profiles. Wavelet analysis finds that the 3-hourly NAVGEM and 1-hourly radar winds both exhibit semi-diurnal, diurnal, and quasi-diurnal variations whose vertical profiles of amplitude and phase are also in good agreement. Wavelet analysis also reveals common time-frequency behavior in both NAVGEM and radar winds throughout the Northern extratropics around the times of major stratospheric sudden warmings (SSWs) in January 2010 and January 2013, with a reduction in semi-diurnal amplitudes beginning around the time of a mesospheric wind reversal at 60°N that precedes the SSW, followed by an amplification of semi-diurnal amplitudes that peaks 10–14 days following the onset of the mesospheric wind reversal. The initial results presented in this study demonstrate that the wind analyses produced by the high-altitude NAVGEM system accurately capture key features in the observed MLT winds during these two boreal winter periods.</p
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