183 research outputs found
Improving meson two-point functions in lattice QCD
We describe and test a method to compute Euclidean meson two-point functions
in lattice QCD. The contribution from the low-lying eigenmodes of the Dirac
operator is averaged over all positions of the quark sources. The contribution
from the higher modes is estimated in the traditional way with one or a few
source points per lattice. In some channels, we observe a significant
improvement in the two-point functions for small quark masses.Comment: 10 pages, 7 figure
Impact of Different Catheter Lock Strategies on Bacterial Colonization of Permanent Central Venous Hemodialysis Catheters
Thirty-nine hemodialysis patients with permanent central venous catheters were analyzed for bacterial catheter colonization comparing different catheter-lock strategies. The closed needleless Tego connector with sodium chloride lock solution was significantly more frequently colonized with bacteria than the standard catheter caps with antimicrobially active citrate lock solution (odds ratio, 0.22 [95% confidence interval, 0.07-0.71]; P = .011
Neurophysiological correlates of residual inhibition in tinnitus: Hints for trait-like EEG power spectra
Objective
To investigate oscillatory brain activity changes following acoustic stimulation in tinnitus and whether these changes are associated with behavioral measures of tinnitus loudness. Moreover, differences in ongoing brain activity between individuals with and without residual inhibition (RI) are examined (responders vs. non-responders).
Methods
Three different types of noise stimuli were administered for acoustic stimulation in 45 tinnitus patients. Subjects resting state brain activity was recorded before and after stimulation via EEG alongside with subjective measurements of tinnitus loudness.
Results
Delta, theta and gamma band power increased, whereas alpha and beta power decreased from pre to post stimulation. Acoustic stimulation responders exhibited reduced gamma and a trend for enhanced alpha activity with the latter localized in the right inferior temporal gyrus. Post stimulation, individuals experiencing RI showed higher theta, alpha and beta power with a peak power difference in the alpha band localized in the right superior temporal gyrus. Neither correlations with behavioral tinnitus measures nor stimulus-specific changes in EEG activity were present.
Conclusions
Our observations might be indicative of trait-specific forms of oscillatory signatures in different subsets of the tinnitus population related to acoustic tinnitus suppression.
Significance
Results and insights are not only useful to understand basic neural mechanisms behind RI but are also valuable for general neural models of tinnitus
Properties of near-zero modes and chiral symmetry breaking
We study localization and chirality properties of eigenvectors of the lattice
Dirac operator. In particular we focus on the dependence of our observables on
the size of the corresponding eigenvalue, which allows us to study the
transition of a near-zero mode into a bulk mode. We analyze ensembles of
quenched SU(3) configurations using a Dirac operator which is a systematic
expansion in path length of a solution of the Ginsparg-Wilson equation. Our
results support the interpretation of the excitations relevant for chiral
symmetry breaking as interacting instantons and anti-instantons.Comment: Minor changes in the discussion, references added. To appear in
Nuclear Physics
RTMS parameters in tinnitus trials: a systematic review
Over the past few years extensive body of research was produced investigating the effects of repetitive transcranial magnetic stimulation (rTMS) for the treatment of chronic tinnitus with heterogeneous results. This heterogeneity is exemplified by two recently published large-scale clinical trials reporting different outcomes. Technical aspects of rTMS were suspected as a potential source for this incongruency. The aim of this systematic review is to examine the overall efficacy as well as to identify possible technical factors relevant for the effectiveness of rTMS tinnitus trials. Via a literature search appropriate original research papers were identified and rTMS parameters were extracted from each study arm for subsequent statistical analysis with respect to observed effects (significant vs. not significant pre-post rTMS effects). Our findings indicate that verum rTMS is superior to sham rTMS as demonstrated by the proportion of significant pre-post contrasts. Some relevant rTMS parameters (e.g., pulse waveform) are not reported. Lower rTMS stimulation intensity was associated with significant effects in verum rTMS arms. An additional stimulation of the DLPFC to the temporal cortex was not found to promote efficacy. Future research should consider differential effects of rTMS induced by technical parameters and strive for an exhaustive reporting of relevant rTMS parameters
Potentials, challenges and visions for future European organic animal farming
There is a serious need for significant and fundamental improvements to the way we currently produce and consume food if we are going to respond meaningfully to the enormous global environmental challenges that face us. The role of animal farming in particular is faced with the challenge of balancing their potential positive contribution to our food system within an effective circular economy while ensuring that the animals on our farms exist as living, sentient beings that are treated in ways that allow their lives, from their perspective, to be worth living
Strategies And Visions For The Future Of Organic Animal Farming
Based on existing knowledge and current research projects, a number of innovative strategies and approaches are proposed that would enable organic animal farming to contribute to a more sustainable and resilient food systems that also impacts positively on our surrounding socio-ecological landscape. The focus is on 1) integrated, multispecies, diversified systems, 2) sustainable foraging strategies and efficient utilisation of natural resources, 3) home grown protein feed especially for monogastric animals, 4) resilience as the core of health development rather than just freedom of diseases, 5) breeding including multipurpose breeds, and 6) enhanced mother-infant contact
Observation of enhanced chiral asymmetries in the inner-shell photoionization of uniaxially oriented methyloxirane enantiomers
Most large molecules are chiral in their structure: they exist as two
enantiomers, which are mirror images of each other. Whereas the rovibronic
sublevels of two enantiomers are almost identical, it turns out that the
photoelectric effect is sensitive to the absolute configuration of the ionized
enantiomer - an effect termed Photoelectron Circular Dichroism (PECD). Our
comprehensive study demonstrates that the origin of PECD can be found in the
molecular frame electron emission pattern connecting PECD to other fundamental
photophysical effects as the circular dichroism in angular distributions
(CDAD). Accordingly, orienting a chiral molecule in space enhances the PECD by
a factor of about 10
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