252 research outputs found
No evidence that prefrontal HD-tDCS influences cue-induced food craving.
This study investigated whether the application of high definition transcranial DC stimulation (HD-tDCS) to the dorsolateral prefrontal cortex reduces cue-induced food craving when combined with food-specific inhibitory control training. Using a within-subjects design, participants (N = 55) received both active and sham HD-tDCS across 2 sessions while completing a Go/No-Go task in which foods were either associated with response inhibition or response execution. Food craving was measured pre and post stimulation using a standardized questionnaire as well as desire to eat ratings for foods associated with both response inhibition and response execution in the training task. Results revealed no effect of HD-tDCS on reducing state food craving or desire to eat. Due to the COVID-19 pandemic, we were unable to achieve our maximum preplanned sample size or our minimum desired Bayesian evidence strength across all a priori hypotheses; however 6 of the 7 hypotheses converged with moderate or stronger evidence in favor of the null hypothesis over the alternative hypothesis. We discuss the importance of individual differences and provide recommendations for future studies with an emphasis on the importance of cognitive interventions
Endoplasmic reticulum targeted GFP reveals ER organization in tobacco NT-1 cells during cell division
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Plant Physiology and Biochemistry, doi:10.1016/j.plaphy.2006.03.003.The endoplasmic reticulum (ER) of plant cells undergoes a drastic reorganization
during cell division. In tobacco NT-1 cells that stably express a GFP construct targeted
to the ER, we have mapped the reorganization of ER that occurs during mitosis and
cytokinesis with confocal laser scanning microscopy. During division, the ER and
nuclear envelope do not vesiculate. Instead, tubules of ER accumulate around the
chromosomes after the nuclear envelope breaks down, with these tubules aligning parallel
to the microtubules of the mitotic spindle. In cytokinesis, the phragmoplast is
particularly rich in ER, and the transnuclear channels and invaginations present in many
interphase cells appear to develop from ER tubules trapped in the developing
phragmoplast. Drug studies, using oryzalin and latrunculin to disrupt the microtubules
and actin microfilaments respectively, demonstrate that during division, the arrangement
of ER is controlled by microtubules and not by actin, which is the reverse of the situation
in interphase cells.Funding for this project included NASA grant # NAGW-4984 to the North
Carolina NSCORT (NASA Specialized Center of Research and Training) (SLG, DAC,
NSA), NSF REU Site Grant #0243930 (NSA), a Sigma Xi Grant-in-Aid Award (SLG),
and Australian Research Council Discovery Grant no. DP0208806 (DAC)
Null orbifolds in AdS, Time Dependence and Holography
We study M/D-branes in a null-brane background. By taking a near horizon
limit, one is left with cosmological models in the corresponding Poincar\'e
patches. To deal with their usual horizons, we either extend these models to
global AdS or remain in the Poincar\'e patch and apply a T-duality
transformation whenever the effective radius of the compact dimension
associated with the null-brane probes distances smaller than the string scale.
The first scenario gives rise to null orbifolds in AdS spaces, which are
described in detail. Their conformal boundaries are singular. The second has a
dual gauge theory description in terms of Super Yang-Mills in the null-brane
background. The latter is a good candidate for a non-perturbative definition of
string theory in a time-dependent background.Comment: 1+25 pages, no figure
On Smooth Time-Dependent Orbifolds and Null Singularities
We study string theory on a non-singular time-dependent orbifold of flat
space, known as the `null-brane'. The orbifold group, which involves only
space-like identifications, is obtained by a combined action of a null Lorentz
transformation and a constant shift in an extra direction. In the limit where
the shift goes to zero, the geometry of this orbifold reproduces an orbifold
with a light-like singularity, which was recently studied by Liu, Moore and
Seiberg (hep-th/0204168). We find that the backreaction on the geometry due to
a test particle can be made arbitrarily small, and that there are scattering
processes which can be studied in the approximation of a constant background.
We quantize strings on this orbifold and calculate the torus partition
function. We construct a basis of states on the smooth orbifold whose tree
level string interactions are nonsingular. We discuss the existence of physical
modes in the singular orbifold which resolve the singularity. We also describe
another way of making the singular orbifold smooth which involves a sandwich
pp-wave.Comment: 24 pages, one figur
Towards actionable international comparisons of health system performance: expert revision of the OECD framework and quality indicators
Objective To review and update the conceptual framework, indicator content and research priorities of the Organisation for Economic Cooperation and Development's (OECD) Health Care Quality Indicators (HCQI) project, after a decade of collaborative work. Design A structured assessment was carried out using a modified Delphi approach, followed by a consensus meeting, to assess the suite of HCQI for international comparisons, agree on revisions to the original framework and set priorities for research and development. Setting International group of countries participating to OECD projects. Participants Members of the OECD HCQI expert group. Results A reference matrix, based on a revised performance framework, was used to map and assess all seventy HCQI routinely calculated by the OECD expert group. A total of 21 indicators were agreed to be excluded, due to the following concerns: (i) relevance, (ii) international comparability, particularly where heterogeneous coding practices might induce bias, (iii) feasibility, when the number of countries able to report was limited and the added value did not justify sustained effort and (iv) actionability, for indicators that were unlikely to improve on the basis of targeted policy interventions. Conclusions The revised OECD framework for HCQI represents a new milestone of a long-standing international collaboration among a group of countries committed to building common ground for performance measurement. The expert group believes that the continuation of this work is paramount to provide decision makers with a validated toolbox to directly act on quality improvement strategie
Time Evolution in Open String Theory
We discuss a general iterative procedure for constructing time dependent
solutions in open string theory describing rolling of a generic tachyon field
away from its maximum. These solutions are characterized by two parameters
labelling the initial position and velocity of the tachyon field, but one of
these parameters can be removed by using time translation symmetry. The Wick
rotated version of the resulting one parameter family of inequivalent solutions
describes a one parameter family of boundary conformal field theories, each
member of which is related to the boundary conformal field theory describing
the original D-brane system by a nearly marginal deformation. We apply this
technique to construct a time dependent solution on a D-brane in bosonic string
theory which can be interpreted as the creation of a lower dimensional brane
during the decay of an unstable D-brane.Comment: LaTeX file, 35 pages, 2 figures, discussion on multiple rolling
tachyons expanded to include the general case, references added; v4: typos
correcte
Chromosomal localization of 15 ion channel genes
Several human Mendelian diseases, including the long-QT syndrome, malignant hyperthermia, and episodic ataxia/myokymia syndrome, have recently been demonstrated to be due to mutations in ion channel genes. Systematic mapping of ion channel genes may therefore reveal candidates for other heritable disorders. In this study, the GenBank and dbEST databases were used to identify members of several ion channel families (voltage-gated calcium and sodium cardiac chloride, and all classes of potassium channels). Genes and ESTs without prior map localization were identified based on GDB and OWL database information and 15 genes and ESTs were selected for mapping. Of these 15, only the serotonin receptor 5HT3R had been previously mapped to a chromosome. A somatic cell hybrid panel (SCH) was screened with an STS from each gene and, if necessary, the results verified by a second SCH panel. For three ESTs, rodent derived PCR products of the same size as the human STS precluded SCH mapping. For these three, human Pl clones were isolated and the genomic location was determined by metaphase FISH. These genes and ESTs can now be further evaluated as candidate genes for inherited cardiac, neuromuscular, and psychiatric disorders mapped to these chromosomes. Furthermore, the ESTs developed in this study can be used to isolate genomic clones, enabling the determination of each transcript's genomic structure and physical map location. This approach may also be applicable to other gene families and may aid in the identification of candidate genes for groups of related heritable disorders.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45548/1/11188_2006_Article_BF02369898.pd
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