1,390 research outputs found
Determining source cumulants in femtoscopy with Gram-Charlier and Edgeworth series
Lowest-order cumulants provide important information on the shape of the
emission source in femtoscopy. For the simple case of noninteracting identical
particles, we show how the fourth-order source cumulant can be determined from
measured cumulants in momentum space. The textbook Gram-Charlier series is
found to be highly inaccurate, while the related Edgeworth series provides
increasingly accurate estimates. Ordering of terms compatible with the Central
Limit Theorem appears to play a crucial role even for nongaussian
distributions.Comment: 11 pages, 2 figure
Cooperative gas adsorption without a phase transition in metal-organic frameworks
Cooperative adsorption of gases by porous frameworks permits more efficient
uptake and removal than does the more usual non-cooperative (Langmuir-type)
adsorption. Cooperativity, signaled by a step-like isotherm, is usually
attributed to a phase transition of the framework. However, the class of
metal-organic frameworks mmen-M(dobpdc) exhibit cooperative adsorption of
CO2 but show no evidence of a phase transition. Here we show how cooperativity
emerges in these frameworks in the absence of a phase transition. We use a
combination of quantum and statistical mechanics to show that cooperativity
results from a sharp but finite increase, with pressure, of the mean length of
chains of CO2 molecules that polymerize within the framework. Our study
provides microscopic understanding of the emergent features of cooperative
binding, including the position, slope and height of the isotherm step, and
indicates how to optimize gas storage and separation in these materials.Comment: 18 pages, 11 figure
An instant preparation method for nucleic acids of filamentous fungi
Preparation methods for both DNA and RNA of filamentous fungi often are labour intensive and unreliable. The rapid preparation protocol presented here has been found to work for Schizophyllum commune and other filamentous fungi
Comparison of the NASA Common Research Model European Transonic Wind Tunnel Test Data to NASA Test Data
Experimental aerodynamic investigations of the NASA Common Research Model have been conducted in the NASA Langley National Transonic Facility, the NASA Ames 11-ft wind tunnel, and the European Transonic Wind Tunnel. In the NASA Ames 11-ft wind tunnel, data have been obtained at only a chord Reynolds number of 5 million for a wing/body/tail = 0 degree incidence configuration. Data have been obtained at chord Reynolds numbers of 5, 19.8 and 30 million for the same configuration in the National Transonic Facility and in the European Transonic Facility. Force and moment, surface pressure, wing bending and twist, and surface flow visualization data were obtained in all three facilities but only the force and moment, surface pressure and wing bending and twist data are presented herein
Attenuated renovascular constrictor responses to angiotensin II in adenosine 1 receptor knockout mice
Deflection of Ultra Slow Light by Earth Gravity on Laboratory Length Scale
The high speed of light in vacuo together with the weakness of Earth gravity
rules out any experimental detection of gravitational deflection of light on
the laboratory length scale. Recent advances in coherent optics that produce
ultra slow light in highly dispersive media with the group velocities down to
~102 ms-1, or even less, however, open up this possibility. In this work, we
present a theoretical study for a possible laboratory observation of the
deflection of such an ultra slow light in the highly dispersive medium under
Earth gravity. Our general relativistic calculation is based on the Gordon
optical metric modified so as to include dispersion. The calculated linear
vertical deflection turns out to be ~0.1 mm for a horizontal traversal of 0.1
m, and a group speed vg ~ 102 ms-1. Experimental realizability and some
conceptual points involved will be briefly discussed.Comment: 8 page
Editorial: γδ T Cells in Cancer
Since the discovery of γδ T cells, this rare and unique component of the immune system has been recognized for its potential in cancer immunology and immunotherapy. In the mid-1980s, it became clear that a major component of adaptive immune responses is the ability of T cell receptors (TCR) to undergo somatic recombination in order to recognize multiple antigens
Nanoscale phase quantification in lead-free (Bi1/2Na1/2)TiO3-BaTiO3 relaxor ferroelectrics by means of Na 23 NMR
We address the unsolved question on the structure of relaxor ferroelectrics at the atomic level by characterizing lead-free piezoceramic solid solutions (100-x)(Bi1/2Na1/2)TiO3-xBaTiO3 (BNT-xBT) (for x=1,4,6, and 15). Based on the relative intensity between spectral components in quadrupolar perturbed Na23 nuclear magnetic resonance, we present direct evidence of the coexistence of cubic and polar local symmetries in these relaxor ferroelectrics. In addition, we demonstrate how the cubic phase vanishes whenever a ferroelectric state is induced, either by field cooling or changing the dopant amount, supporting the relation between this cubic phase and the relaxor state.open0
3D Spectrophotometry of Planetary Nebulae in the Bulge of M31
We introduce crowded field integral field (3D) spectrophotometry as a useful
technique for the study of resolved stellar populations in nearby galaxies. As
a methodological test, we present a pilot study with selected extragalactic
planetary nebulae (XPN) in the bulge of M31, demonstrating how 3D spectroscopy
is able to improve the limited accuracy of background subtraction which one
would normally obtain with classical slit spectroscopy. It is shown that due to
the absence of slit effects, 3D is a most suitable technique for
spectrophometry. We present spectra and line intensities for 5 XPN in M31,
obtained with the MPFS instrument at the Russian 6m BTA, INTEGRAL at the WHT,
and with PMAS at the Calar Alto 3.5m Telescope. Using 3D spectra of bright
standard stars, we demonstrate that the PSF is sampled with high accuracy,
providing a centroiding precision at the milli-arcsec level. Crowded field 3D
spectrophotometry and the use of PSF fitting techniques is suggested as the
method of choice for a number of similar observational problems, including
luminous stars in nearby galaxies, supernovae, QSO host galaxies,
gravitationally lensed QSOs, and others.Comment: (1) Astrophysikalisches Institut Potsdam, (2) University of Durham.
18 pages, 11 figures, accepted for publication in Ap
Controlled Assembly of Macromolecular β-Sheet Fibrils
Construction of functional molecular devices by directed assembly processes is one of the main challenges in the field of nanotechnology. Many approaches to this challenge use biological assembly as a source of inspiration for the build up of new materials with controlled organization at the nanoscale. In particular, the self-assembly properties of β-sheet peptides have been used in the design of supramolecular materials, such as tapes, nanotubes, and fibrils
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