1,800 research outputs found
Predicting the readability of transparent text
Will a simple global masking model based on image detection be successful at predicting the readability of transparent text? Text readability was measured for two types of transparent text: additive (as occurs in head-up displays) and multiplicative (which occurs in see-through liquid crystal display virtual reality displays). Text contrast and background texture were manipulated. Data from two previous experiments were also included (one using very low contrasts on plain backgrounds, and the other using higher-contrast opaque text on both plain and textured backgrounds). All variables influenced readability in at least an interactive manner. When there were background textures, the global masking index (that combines text contrast and background root mean square contrast) was a good predictor of search times (r = 0.89). When the masking was adjusted to include the text pixels as well as the background pixels in computations of mean luminance and contrast variability, predictability improved further (r = 0.91)
Possible multiparticle ridge-like correlations in very high multiplicity proton-proton collisions
The CMS collaboration at the LHC has reported a remarkable and unexpected
phenomenon in very high-multiplicity high energy proton-proton collisions: a
positive correlation between two particles produced at similar azimuthal
angles, spanning a large range in rapidity. We suggest that this "ridge"-like
correlation may be a reflection of the rare events generated by the collision
of aligned flux tubes connecting the valence quarks in the wave functions of
the colliding protons. The "spray" of particles resulting from the approximate
line source produced in such inelastic collisions then gives rise to events
with a strong correlation between particles produced over a large range of both
positive and negative rapidity. We suggest an additional variable that is
sensitive to such a line source which is related to a commonly used measure,
ellipticity.Comment: Updated figure. Version to be published in Physics Letters
THE SYNTHESIS, ASSEMBLY, AND SECRETION OF GAMMA GLOBULIN BY MOUSE MYELOMA CELLS : VI. ASSEMBLY OF IGM PROTEINS
The study of the synthesis, assembly, and secretion of IgM by seven murine myeloma tumors has revealed that free mu chain can be detected intracellularly after release from the ribosome. It combines with light chains to form µL. The major intracellular protein in six of the seven tumors was the 8S subunit. One tumor contained considerable amounts of 19S material intracellularly. Those tumors that did not contain 19S IgM intracellulariy appeared to assemble the subunits outside the cell
Spontaneous fission modes and lifetimes of super-heavy elements in the nuclear density functional theory
Lifetimes of super-heavy (SH) nuclei are primarily governed by alpha decay
and spontaneous fission (SF). Here we study the competing decay modes of
even-even SH isotopes with 108 <= Z <= 126 and 148 <= N <= 188 using the
state-of-the-art self-consistent nuclear density functional theory framework
capable of describing the competition between nuclear attraction and
electrostatic repulsion. The collective mass tensor of the fissioning
superfluid nucleus is computed by means of the cranking approximation to the
adiabatic time-dependent Hartree-Fock-Bogoliubov approach. Along the path to
fission, our calculations allow for the simultaneous breaking of axial and
space inversion symmetries; this may result in lowering SF lifetimes by more
than seven orders of magnitude in some cases. We predict two competing SF
modes: reflection-symmetric and reflection-asymmetric.The shortest-lived SH
isotopes decay by SF; they are expected to lie in a narrow corridor formed by
Hs, Fl, and Uuo that separates the regions of SH
nuclei synthesized in "cold fusion" and "hot fusion" reactions. The region of
long-lived SH nuclei is expected to be centered on Ds with a total
half-life of ?1.5 days.Comment: 6 pages, 4 figure
Powers of the Vandermonde determinant, Schur Functions, and recursive formulas
Since every even power of the Vandermonde determinant is a symmetric
polynomial, we want to understand its decomposition in terms of the basis of
Schur functions. We investigate several combinatorial properties of the
coefficients in the decomposition. In particular, we give recursive formulas
for the coefficient of the Schur function s_{\m} in the decomposition of an
even power of the Vandermonde determinant in variables in terms of the
coefficient of the Schur function s_{\l} in the decomposition of the same
even power of the Vandermonde determinant in variables if the Young diagram
of \m is obtained from the Young diagram of \l by adding a tetris type
shape to the top or to the left. An extended abstract containing the statement
of the results presented here appeared in the Proceedings of FPSAC11Comment: 23 pages; extended abstract appeared in the Proceedings of FPSAC1
A detailed view into the eruption clouds of Santiaguito volcano, Guatemala, using Doppler radar
Using Doppler radar technology we are able to show that eruptions at Santiaguito volcano, Guatemala, are comprised of multiple explosive degassing pulses occurring at a frequency of 0.2 to 0.3 Hz. The Doppler radar system was installed about 2.7 km away from the active dome on the top of Santa Maria volcano. During four days of continuous measurement 157 eruptive events were recorded. The Doppler radar data reveals a vertical uplift of the dome surface of about 50 cm immediately prior to a first degassing pulse. Particle velocities range from 10 to 15 m/s (in the line of sight of the radar). In 80% of the observed eruptions a second degassing pulse emanates from the dome with significantly higher particle velocities (20-25 m/s again line of sight) and increased echo power, which implies an increase in mass flux. We carry out numerical experiments of ballistic particle transport and calculate corresponding synthetic radar signals. These calculations show that the observations are consistent with a pulsed release of material from the dome of Santiaguito volcano
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