2,961 research outputs found
The Shears Mechanism in 142Gd in the Skyrme-Hartree-Fock Method with the Tilted-Axis Cranking
We report on the first Skyrme-Hartree-Fock calculations with the tilted-axis
cranking in the context of magnetic rotation. The mean field symmetries,
differences between phenomenological and self-consistent methods and the
generation of shears-like structures in the mean field are discussed.
Significant role of the time-odd spin-spin effective interaction is pointed
out. We reproduce the shears mechanism, but quantitative agreement with
experiment is rather poor. It may have to do with too large core polarization,
lack of pairing correlations or properties of the Skyrme force.Comment: Presented at the XXVII Mazurian Lakes School of Physics, September
2-9 2001, Krzyze, Poland, Submitted to Acta Physica Polonic
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Histone Hypervariants H2A.Z.1 and H2A.Z.2 Play Independent and Context-Specific Roles in Neuronal Activity-Induced Transcription of Arc/Arg3.1 and Other Immediate Early Genes.
The histone variant H2A.Z is an essential and conserved regulator of eukaryotic gene transcription. However, the exact role of this histone in the transcriptional process remains perplexing. In vertebrates, H2A.Z has two hypervariants, H2A.Z.1 and H2A.Z.2, that have almost identical sequences except for three amino acid residues. Due to such similarity, functional specificity of these hypervariants in neurobiological processes, if any, remain largely unknown. In this study with dissociated rat cortical neurons, we asked if H2A.Z hypervariants have distinct functions in regulating basal and activity-induced gene transcription. Hypervariant-specific RNAi and microarray analyses revealed that H2A.Z.1 and H2A.Z.2 regulate basal expression of largely nonoverlapping gene sets, including genes that code for several synaptic proteins. In response to neuronal activity, rapid transcription of our model gene Arc is impaired by depletion of H2A.Z.2, but not H2A.Z.1. This impairment is partially rescued by codepletion of the H2A.Z chaperone, ANP32E. In contrast, under a different context (after 48 h of tetrodotoxin, TTX), rapid transcription of Arc is impaired by depletion of either hypervariant. Such context-dependent roles of H2A.Z hypervariants, as revealed by our multiplexed gene expression assays, are also evident with several other immediate early genes, where regulatory roles of these hypervariants vary from gene to gene under different conditions. Together, our data suggest that H2A.Z hypervariants have context-specific roles that complement each other to mediate activity-induced neuronal gene transcription
Evaluation of thermal pattern distributions in racehorse saddles using infrared thermography
The impact of a rider’s and saddle’s mass on saddle thermal pattern distribution was evalu ated using infrared thermography (IRT). Eighteen racehorses were ridden by four riders with
their own saddle. Images of the saddle panels were captured at each of six thermographic
examinations. On each image, six regions of interest (ROIs) were marked on the saddle
panels. The mean temperature for each ROI was extracted. To evaluate the influence of
load on saddle fit, 4 indicators were used: ΔTmax (difference between the mean temperature
of the warmest and coolest ROI); standard deviation of the mean temperature of the six
ROIs; right/left; bridging/rocking and front/back thermal pattern indicator. Incorrect saddle fit
was found in 25 measurements (23.1%) with ΔTmax greater than 2˚C. The relationships
between rider and saddle fit as well as saddle fit and horse were significant (p<0.001). An
average ΔTmax in rider A was significantly higher than in other riders (p<0.001). The right/left
thermal pattern differed significantly from the optimal value for riders A and B; while the
bridging/rocking thermal pattern differed significantly from this value for riders A, C and D
(p<0.05). Front saddle thermal pattern was most frequent for rider A (41.5%), whereas back
saddle thermal pattern was most frequent for rider C (85.7%). Measurement of the mean
temperature in 6 ROIs on saddle panels after training was helpful in assessing the influence
of rider and saddle mass on saddle fit. IRT offered a non-invasive, rapid and simple method
for assessing load on thermal pattern distribution in race saddles.info:eu-repo/semantics/publishedVersio
Prostate-specific antigen testing in inner London general practices: are those at higher risk most likely to get tested?
This study was funded by the Guy’s and St Thomas’ Hospital Charity (Fund 201)
Issues and Opportunities in Exotic Hadrons
The last few years have been witness to a proliferation of new results
concerning heavy exotic hadrons. Experimentally, many new signals have been
discovered that could be pointing towards the existence of tetraquarks,
pentaquarks, and other exotic configurations of quarks and gluons.
Theoretically, advances in lattice field theory techniques place us at the cusp
of understanding complex coupled-channel phenomena, modelling grows more
sophisticated, and effective field theories are being applied to an ever
greater range of situations. It is thus an opportune time to evaluate the
status of the field. In the following, a series of high priority experimental
and theoretical issues concerning heavy exotic hadrons is presented.Comment: White paper from INT workshop, "Modern Exotic Hadrons". References
added. Version to appear in Chinese Physics
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