1,456 research outputs found
Letter: reproducible evidence shows that exclusive enteral nutrition significantly reduces faecal calprotectin concentrations in children with active Crohn's Disease
No abstract available
Sum rules for isospin centroids in pick-up reactions on general multishell target states
Sum Rules equations for pick-up reactions are presented for the first time
for the energy centroids of states both for the isospin T_< (\equiv T_0 - 1
\over 2) and T_> (\equiv T_0 + {1 \over 2}) of the final nucleus when a nucleon
is picked up from a general multishell target state with isospin T_0. These
equations contain two-body correlation terms, , which, at the present
moment, are difficult to handle analytically. These terms are managed by
combining these equations with the known stripping reactions equations. Sample
applications of these equations to experimental data are presented.Comment: 11 pages, LaTe
An international comparison of surface texture parameters quantification on polymer artefacts using optical instruments
An international comparison of optical instruments measuring polymer surfaces with arithmetic mean height values in the sub-micrometre range has been carried out. The comparison involved sixteen optical surface texture instruments (focus variation instruments, confocal microscopes and coherent scanning interferometers) from thirteen research laboratories worldwide. Results demonstrated that: (i) Agreement among different instruments could be achieved to a limited extent; (ii) standardised guidelines for uncertainty evaluation of areal surface parameters are needed for users; (iii) it is essential that the performance characteristics (and especially the spatial frequency response) of an instrument is understood prior to a measurement
Five Dimensional Cosmological Models in General Relativity
A Five dimensional Kaluza-Klein space-time is considered in the presence of a
perfect fluid source with variable G and . An expanding universe is
found by using a relation between the metric potential and an equation of
state. The gravitational constant is found to decrease with time as whereas the variation for the cosmological constant follows as
, and
where is the equation of state parameter and is the scale factor.Comment: 13 pages, 4 figures, accepted in Int. J. Theor. Phy
Cross-Correlation Studies with CMB Polarization Maps
The free-electron population during the reionized epoch rescatters CMB
temperature quadrupole and generates a now well-known polarization signal at
large angular scales. While this contribution has been detected in the
temperature-polarization cross power spectrum measured with WMAP data, due to
the large cosmic variance associated with anisotropy measurements at tens of
degree angular scales only limited information related to reionization, such as
the optical depth to electron scattering, can be extracted. The inhomogeneities
in the free-electron population lead to an additional secondary polarization
anisotropy contribution at arcminute scales. While the fluctuation amplitude,
relative to dominant primordial fluctuations, is small, we suggest that a
cross-correlation between arcminute scale CMB polarization data and a tracer
field of the high redshift universe, such as through fluctuations captured by
the 21 cm neutral Hydrogen background or those in the infrared background
related to first proto-galaxies, may allow one to study additional details
related to reionization. For this purpose, we discuss an optimized higher order
correlation measurement, in the form of a three-point function, including
information from large angular scale CMB temperature anisotropies in addition
to arcminute scale polarization signal related to inhomogeneous reionization.
We suggest that the proposed bispectrum can be measured with a substantial
signal-to-noise ratio and does not require all-sky maps of CMB polarization or
that of the tracer field. A measurement such as the one proposed may allow one
to establish the epoch when CMB polarization related to reionization is
generated and to address if the universe was reionized once or twice.Comment: 13 pages, 7 figures; Version in press with Phys. Rev.
Combined CI+MBPT calculations of energy levels and transition amplitudes in Be, Mg, Ca, and Sr
Configuration interaction (CI) calculations in atoms with two valence
electrons, carried out in the V(N-2) Hartree-Fock potential of the core, are
corrected for core-valence interactions using many-body perturbation theory
(MBPT). Two variants of the mixed CI+MBPT theory are described and applied to
obtain energy levels and transition amplitudes for Be, Mg, Ca, and Sr
Weak Field Black Hole Formation in Asymptotically AdS Spacetimes
We use the AdS/CFT correspondence to study the thermalization of a strongly
coupled conformal field theory that is forced out of its vacuum by a source
that couples to a marginal operator. The source is taken to be of small
amplitude and finite duration, but is otherwise an arbitrary function of time.
When the field theory lives on , the source sets up a
translationally invariant wave in the dual gravitational description. This wave
propagates radially inwards in space and collapses to form a black
brane. Outside its horizon the bulk spacetime for this collapse process may
systematically be constructed in an expansion in the amplitude of the source
function, and takes the Vaidya form at leading order in the source amplitude.
This solution is dual to a remarkably rapid and intriguingly scale dependent
thermalization process in the field theory. When the field theory lives on a
sphere the resultant wave either slowly scatters into a thermal gas (dual to a
glueball type phase in the boundary theory) or rapidly collapses into a black
hole (dual to a plasma type phase in the field theory) depending on the time
scale and amplitude of the source function. The transition between these two
behaviors is sharp and can be tuned to the Choptuik scaling solution in
.Comment: 50 pages + appendices, 6 figures, v2: Minor revisions, references
adde
Mesoscopic Fano Effect in a Quantum Dot Embedded in an Aharonov-Bohm Ring
The Fano effect, which occurs through the quantum-mechanical cooperation
between resonance and interference, can be observed in electron transport
through a hybrid system of a quantum dot and an Aharonov-Bohm ring. While a
clear correlation appears between the height of the Coulomb peak and the real
asymmetric parameter for the corresponding Fano lineshape, we need to
introduce a complex to describe the variation of the lineshape by the
magnetic and electrostatic fields. The present analysis demonstrates that the
Fano effect with complex asymmetric parameters provides a good probe to detect
a quantum-mechanical phase of traversing electrons.Comment: REVTEX, 9 pages including 8 figure
Pride and popcorn: consuming the idea of community at film screenings in the Turkish diaspora
A range of studies have revealed the interrelatedness of identity construction, community formation and media among diasporas, mostly focusing on domestic contexts. Seeking to add further nuance to the understanding of the social lives of diasporas, we concentrate on media culture in the public environment of the film theatre. The significance of diasporic film consumption is investigated through a local audience study of Turkish film screenings in Antwerp. The phenomenon of the screenings was analysed through a multi-method approach, including 536 questionnaires among audiences, 19 in-depth interviews and 3 group interviews, along with previous findings (on distribution and exploitation) of the same project. The results show that Turkish films are almost exclusively attended by people with Turkish roots, creating a Turkish diasporic space within the boundaries of the urban and the public. The audience study shows that the screenings fulfil a major social role but also affect understandings of community
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