591 research outputs found
Profile measurements of plasma columns using microwave resonant cavities
Microwave resonant cavity measurements of radial electron density profile of positive column of gas discharg
Lorentz transformation and vector field flows
The parameter changes resulting from a combination of Lorentz transformation
are shown to form vector field flows. The exact, finite Thomas rotation angle
is determined and interpreted intuitively. Using phase portraits, the
parameters evolution can be clearly visualized. In addition to identifying the
fixed points, we obtain an analytic invariant, which correlates the evolution
of parameters.Comment: 11 pages, 3 figures. Section IV revised and title change
Shear instabilities of freely standing thermotropic smectic-A films
In this Letter we discuss theoretically the instabilities of thermotropic
freely standing smectic-A films under shear flow\cite{re:wu}. We show that, in
Couette geometry, the centrifugal force pushes the liquid crystal toward the
outer boundary and induces smectic layer dilation close to the outer boundary.
Under strong shear, this effect induces a layer buckling instability. The
critical shear rate is proportional to , where is the thickness
of the film.Comment: 12 pages, 2 figure
Texture Specific Mass Matrices and CP violating asymmetry in B^o_d({\bar B}^o_d) -> \psi K_S
In the context of texture 4 - zero and texture 5 - zero hierarchical quark
mass matrices, CP violating asymmetry in
(sin2) has been evaluated by considering quark masses at scale.
For a particular viable texture 4 - zero mass matrix the range of sin2\beta is:
0.27 - 0.60 and for the corresponding texture 5 - zero case it is 0.31 - 0.59.
Further our calculations reveal a crucial dependence of sin2 on light
quark masses as well as the phase in this sector.Comment: 10 latex pages, 4 EPS figure
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Tokamak x ray diagnostic instrumentation
Three classes of x-ray diagnostic instruments enable measurement of a variety of tokamak physics parameters from different features of the x-ray emission spectrum. (1) The soft x-ray (1 to 50 keV) pulse-height-analysis (PHA) diagnostic measures impurity concentrations from characteristic line intensities and the continuum enhancement, and measures the electron temperature from the continuum slope. (2) The Bragg x-ray crystal spectrometer (XCS) measures the ion temperature and neutral-beam-induced toroidal rotation velocity from the Doppler broadening and wavelength shift, respectively, of spectral lines of medium-Z impurity ions. Impurity charge state distributions, precise wavelengths, and inner-shell excitation and recombination rates can also be studied. X rays are diffracted and focused by a bent crystal onto a position-sensitive detector. The spectral resolving power E/..delta..E is greater than 10/sup 4/ and time resolution is 10 ms. (3) The x-ray imaging system (XIS) measures the spatial structure of rapid fluctuations (0.1 to 100 kHZ) providing information on MHD phenomena, impurity transport rates, toroidal rotation velocity, plasma position, and the electron temperature profile. It uses an array of silicon surface-barrier diodes which view different chords of the plasma through a common slot aperture and operate in current (as opposed to counting) mode. The effectiveness of shields to protect detectors from fusion-neutron radiation effects has been studied both theoretically and experimentally
Dephosphorylation of Nucleophosmin by PP1β Facilitates pRB Binding and Consequent E2F1-dependent DNA Repair
We report a new pathway through which PP1β signals to nucleophosmin (NPM) in response to DNA damage. UV induces dephosphorylation of NPM at multiple sites, leading to enhancement of complex formation between NPM and retinoblastoma tumor suppressor protein and the subsequent upregulation of E2F1. Consequently, such signaling pathway potentiates the cellular DNA repair capacity
Testing the predictive ability of technical analysis using a new stepwise test without data snooping bias
In the finance literature, statistical inferences for large-scale testing problems usually suffer from data snooping bias. In this paper we extend the "superior predictive ability" (SPA) test of Hansen (2005, JBES) to a stepwise SPA test that can identify predictive models without potential data snooping bias. It is shown analytically and by simulations that the stepwise SPA test is more powerful than the stepwise Reality Check test of Romano and Wolf (2005, Econometrica). We then apply the proposed test to examine the predictive ability of technical trading rules based on the data of growth and emerging market indices and their exchange traded funds (ETFs). It is found that technical trading rules have significant predictive power for these markets, yet such evidence weakens after the ETFs are introduced. © 2009.preprin
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