1,076 research outputs found
Wide angle long eye relief eyepiece Patent
Wide angle eyepiece with long eye-relief distanc
Single crystals of metal solid solutions: A study
Report describes growth of silver-alloy crystals under widely varying conditions of growth rate, temperature gradient, and magnetic field. Role of gravitation and convection on crystal substructure is analyzed, as well as influence of magnetic fields applied during crystallization
Investigation of immiscible systems and potential applications
The droplet coalescence kinetics at 0 g and 1 g were considered for two systems which contained liquid droplets in a host liquid. One of these (Al-In) typified a system containing a liquid phase miscibility gap and the order (oil-water) a mixture of two essentially insoluble liquids. A number of coalescence mechanisms potentially prominent at low g in this system were analyzed and explanations are presented for the observed unusual stability of the emulsion. Ground base experiments were conducted on the coalescence of In droplets in and Al-In alloy during cooling through the miscibility gap at different cooling rates. These were in qualitative agreement with the computer simulation. Potential applications for systems with liquid phase miscibility gaps were explored. Possibilities included superconductors, electrical contact materials, superplastic materials, catalysts, magnetic materials, and others. The role of space processing in their production was also analyzed
Phase separation in transparent liquid-liquid miscibility gap systems
A program to be carried out on transparent liquid-phase miscibility gap materials was developed for the purpose of acquiring additional insight into the separation process occurring in these systems. The transparency feature allows the reaction to be viewed directly through light scattering and holographic methods
Diffusive hidden Markov model characterization of DNA looping dynamics in tethered particle experiments
In many biochemical processes, proteins bound to DNA at distant sites are
brought into close proximity by loops in the underlying DNA. For example, the
function of some gene-regulatory proteins depends on such DNA looping
interactions. We present a new technique for characterizing the kinetics of
loop formation in vitro, as observed using the tethered particle method, and
apply it to experimental data on looping induced by lambda repressor. Our
method uses a modified (diffusive) hidden Markov analysis that directly
incorporates the Brownian motion of the observed tethered bead. We compare
looping lifetimes found with our method (which we find are consistent over a
range of sampling frequencies) to those obtained via the traditional
threshold-crossing analysis (which can vary depending on how the raw data are
filtered in the time domain). Our method does not involve any time filtering
and can detect sudden changes in looping behavior. For example, we show how our
method can identify transitions between long-lived, kinetically distinct states
that would otherwise be difficult to discern
Youth and Religion: The Gameboy Generation Goes to Church
Using the secularization theory and the Marxist notion of religion as masking class conscience one would expect the importance of religion and religious involvement today to wane and be limited to lower class members. To challenge this expectation, using a representative national telephone survey of 2004 youth (ages 11–18) and their parents, we attempt to answer the following two questions: How religious are teenagers, and what may explain variation in religious perception and involvement among teens. Findings suggest that religion remains perceived as very important by most teenagers and parents report that about two-thirds of teenagers attended a place of worship at least monthly and that two out of five attended a social group sponsored by a religious organization. These findings do not support the secularization theory. As expected, parental attendance of religious worship, teen’s age, and teen’s ethnicity and gender were significantly associated with three variables of religious behavior and attendance. In contrast to the Marxist notion of religion, measures of socio-economic status indicate that, in the contemporary United States, religious participation, but not beliefs, is largely the domain of the middle-upper classes
Synergistic assembly of human pre-spliceosomes across introns and exons
Most human genes contain multiple introns, necessitating mechanisms to effectively define exons and ensure their proper connection by spliceosomes. Human spliceosome assembly involves both cross-intron and cross-exon interactions, but how these work together is unclear. We examined in human nuclear extracts dynamic interactions of single pre-mRNA molecules with individual fluorescently tagged spliceosomal subcomplexes to investigate how cross-intron and cross-exon processes jointly promote pre-spliceosome assembly. U1 subcomplex bound to the 5\u27 splice site of an intron acts jointly with U1 bound to the 5\u27 splice site of the next intron to dramatically increase the rate and efficiency by which U2 subcomplex is recruited to the branch site/3\u27 splice site of the upstream intron. The flanking 5\u27 splice sites have greater than additive effects implying distinct mechanisms facilitating U2 recruitment. This synergy of 5\u27 splice sites across introns and exons is likely important in promoting correct and efficient splicing of multi-intron pre-mRNAs
Security and Composability of Randomness Expansion from Bell Inequalities
The nonlocal behavior of quantum mechanics can be used to generate guaranteed
fresh randomness from an untrusted device that consists of two nonsignalling
components; since the generation process requires some initial fresh randomness
to act as a catalyst, one also speaks of randomness expansion. Colbeck and Kent
proposed the first method for generating randomness from untrusted devices,
however, without providing a rigorous analysis. This was addressed subsequently
by Pironio et al. [Nature 464 (2010)], who aimed at deriving a lower bound on
the min-entropy of the data extracted from an untrusted device, based only on
the observed non-local behavior of the device. Although that article succeeded
in developing important tools towards the acquired goal, it failed in putting
the tools together in a rigorous and correct way, and the given formal claim on
the guaranteed amount of min-entropy needs to be revisited. In this paper we
show how to combine the tools provided by Pironio et al., as to obtain a
meaningful and correct lower bound on the min-entropy of the data produced by
an untrusted device, based on the observed non-local behavior of the device.
Our main result confirms the essence of the improperly formulated claims of
Pironio et al., and puts them on solid ground. We also address the question of
composability and show that different untrusted devices can be composed in an
alternating manner under the assumption that they are not entangled. This
enables for superpolynomial randomness expansion based on two untrusted yet
unentangled devices.Comment: 12 pages, v3: significant changes: security is proven against
adversaries holding only classical side informatio
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