15,935 research outputs found
All quiet on the neuronal front: NMDA receptor inhibition by prion protein
The normal function of the prion protein (PrP)—the causative agent of mad cow or prion disease—has long remained out of reach. Deciphering PrP's function may help to unravel the complex chain of events triggered by PrP misfolding during prion disease. In this issue of the JCB, an exciting paper (Khosravani, H., Y. Zhang, S. Tsutsui, S. Hameed, C. Altier, J. Hamid, L. Chen, M. Villemaire, Z. Ali, F.R. Jirik, and G.W. Zamponi. 2008. J. Cell Biol. 181:551–565) connects diverse observations regarding PrP into a coherent framework whereby PrP dampens the activity of an N-methyl-D-aspartate (NMDA) receptor (NMDAR) subtype and reduces excitotoxic lesions. The findings of this study suggest that understanding the normal function of proteins associated with neurodegenerative disease may elucidate the molecular pathogenesis
Gaussian Sum-Rule Analysis of Scalar Gluonium and Quark Mesons
Gaussian sum-rules, which are related to a two-parameter Gaussian-weighted
integral of a hadronic spectral function, are able to examine the possibility
that more than one resonance makes a significant contribution to the spectral
function. The Gaussian sum-rules, including instanton effects, for scalar
gluonic and non-strange scalar quark currents clearly indicate a distribution
of the resonance strength in their respective spectral functions. Furthermore,
analysis of a two narrow resonance model leads to excellent agreement between
theory and phenomenology in both channels. The scalar quark and gluonic
sum-rules are remarkably consistent in their prediction of masses of
approximately 1.0 GeV and 1.4 GeV within this model. Such a similarity would be
expected from hadronic states which are mixtures of gluonium and quark mesons.Comment: latex2e using amsmath, 11 pages, 4 eps figures embedded in latex
file. Write-up of presentation for the 2003 SUNY IT (Utica) workshop on
scalar meson
Masses of Open-Flavour Heavy-Light Hybrids from QCD Sum-Rules
We use QCD Laplace sum-rules to predict masses of open-flavour heavy-light
hybrids where one of the hybrid's constituent quarks is a charm or bottom and
the other is an up, down, or strange. We compute leading-order, diagonal
correlation functions of several hybrid interpolating currents, taking into
account QCD condensates up to dimension-six, and extract hybrid mass
predictions for all , as well as explore possible
mixing effects with conventional quark-antiquark mesons. Within theoretical
uncertainties, our results are consistent with a degeneracy between the
heavy-nonstrange and heavy-strange hybrids in all channels. We find a
similar mass hierarchy of , , and states (a state
lighter than essentially degenerate and states) in both the
charm and bottom sectors, and discuss an interpretation for the states.
If conventional meson mixing is present the effect is an increase in the hybrid
mass prediction, and we estimate an upper bound on this effect.Comment: 24 pages, 8 figures. Mass predictions updated from previous version
to reflect corrected sign error in sum rule analysis. Mixing analysis and
examination of higher weight sum-rules added. To be published in JHE
Solid State Television Camera (CID)
The design, development and test are described of a charge injection device (CID) camera using a 244x248 element array. A number of video signal processing functions are included which maximize the output video dynamic range while retaining the inherently good resolution response of the CID. Some of the unique features of the camera are: low light level performance, high S/N ratio, antiblooming, geometric distortion, sequential scanning and AGC
Daily Scheduled High Fat Meals Moderately Entrain Behavioral Anticipatory Activity, Body Temperature, and Hypothalamic c-Fos Activation
When fed in restricted amounts, rodents show robust activity in the hours preceding expected meal delivery. This process, termed food anticipatory activity (FAA), is independent of the light-entrained clock, the suprachiasmatic nucleus, yet beyond this basic observation there is little agreement on the neuronal underpinnings of FAA. One complication in studying FAA using a calorie restriction model is that much of the brain is activated in response to this strong hunger signal. Thus, daily timed access to palatable meals in the presence of continuous access to standard chow has been employed as a model to study FAA in rats. In order to exploit the extensive genetic resources available in the murine system we extended this model to mice, which will anticipate rodent high fat diet but not chocolate or other sweet daily meals (Hsu, Patton, Mistlberger, and Steele; 2010, PLoS ONE e12903). In this study we test additional fatty meals, including peanut butter and cheese, both of which induced modest FAA. Measurement of core body temperature revealed a moderate preprandial increase in temperature in mice fed high fat diet but entrainment due to handling complicated interpretation of these results. Finally, we examined activation patterns of neurons by immunostaining for the immediate early gene c-Fos and observed a modest amount of entrainment of gene expression in the hypothalamus of mice fed a daily fatty palatable meal
Performance of the cross-product steering law for the transearth injection phase
Steering law for transearth injection between circular lunar orbit and vector
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