8,748 research outputs found
Effective operator formalism for open quantum systems
We present an effective operator formalism for open quantum systems.
Employing perturbation theory and adiabatic elimination of excited states for a
weakly driven system, we derive an effective master equation which reduces the
evolution to the ground-state dynamics. The effective evolution involves a
single effective Hamiltonian and one effective Lindblad operator for each
naturally occurring decay process. Simple expressions are derived for the
effective operators which can be directly applied to reach effective equations
of motion for the ground states. We compare our method with the hitherto
existing concepts for effective interactions and present physical examples for
the application of our formalism, including dissipative state preparation by
engineered decay processes.Comment: 11 pages, 6 figure
On possible interactions between upper and lower atmosphere
Geomagnetic data was compared with data on tropospheric and stratospheric circulation characteristics; a statistically significant shrinking was found in areal extent of the stratospheric vortex from the third to the eighth day following a 'geomagnetic storm' The meridionality of the 30 640-m contour line at 10 millibars increases markedly from 5 to 8 days after the storm. During the contraction of the polar vortex edge, the mean height of the vortex central contour decreases only slightly. This indicates that a stratospheric warming event is associated with a steepening of the contour gradient rather than a warming over the entire area of the stratospheric polar vortex. The troposphere reacts to these weak, but significant, stratospheric warming events by a shrinkage of the area of the 500-millibar cold air pool. This shrinkage commences about 3 days after the stratospheric warming. The investigation indicates that the energy input into the stratosphere that is received in conjunction with the geomagnetic disturbance has to come at a propitious time, when the stratospheric-tropospheric circulation system is not already undergoing a major readjustment because of an inherent dynamic instability
Space-contained conflict revision, for geographic information
Using qualitative reasoning with geographic information, contrarily, for
instance, with robotics, looks not only fastidious (i.e.: encoding knowledge
Propositional Logics PL), but appears to be computational complex, and not
tractable at all, most of the time. However, knowledge fusion or revision, is a
common operation performed when users merge several different data sets in a
unique decision making process, without much support. Introducing logics would
be a great improvement, and we propose in this paper, means for deciding -a
priori- if one application can benefit from a complete revision, under only the
assumption of a conjecture that we name the "containment conjecture", which
limits the size of the minimal conflicts to revise. We demonstrate that this
conjecture brings us the interesting computational property of performing a
not-provable but global, revision, made of many local revisions, at a tractable
size. We illustrate this approach on an application.Comment: 14 page
Prebiotic Oligosaccharides Potentiate Host Protective Responses against L. Monocytogenes Infection.
Prebiotic oligosaccharides are used to modulate enteric pathogens and reduce pathogen shedding. The interactions with prebiotics that alter Listeria monocytogenes infection are not yet clearly delineated. L. monocytogenes cellular invasion requires a concerted manipulation of host epithelial cell membrane receptors to initiate internalization and infection often via receptor glycosylation. Bacterial interactions with host glycans are intimately involved in modulating cellular responses through signaling cascades at the membrane and in intracellular compartments. Characterizing the mechanisms underpinning these modulations is essential for predictive use of dietary prebiotics to diminish pathogen association. We demonstrated that human milk oligosaccharide (HMO) pretreatment of colonic epithelial cells (Caco-2) led to a 50% decrease in Listeria association, while Biomos pretreatment increased host association by 150%. L. monocytogenes-induced gene expression changes due to oligosaccharide pretreatment revealed global alterations in host signaling pathways that resulted in differential subcellular localization of L. monocytogenes during early infection. Ultimately, HMO pretreatment led to bacterial clearance in Caco-2 cells via induction of the unfolded protein response and eIF2 signaling, while Biomos pretreatment resulted in the induction of host autophagy and L. monocytogenes vacuolar escape earlier in the infection progression. This study demonstrates the capacity of prebiotic oligosaccharides to minimize infection through induction of host-intrinsic protective responses
The future of the Protestant Church: Estimates for Austria and for the Provinces of Burgenland, Carinthia and Vienna
Secularization and migration have substantially affected the place of the Protestant Church in the Austrian society in the last decades. The number of members has been shrinking markedly from 447 thousand members in 1971 to 278 thousand in 2018. The trend is visible across all provinces, although the magnitude is stronger in Vienna where both disaffiliation and international migration are stronger: In the capital city, the Protestant population diminished from 126 thousand to 47 thousand over the 1971-2018 period. Using population projections of membership to the Protestant Church, we look at the potential future of affiliation to the Protestant Church in Austria, and in three provinces: Burgenland, Carinthia, and Vienna from 2018 to 2048, considering different paths of fertility and disaffiliation. We also look at the impact of different scenarios regarding the composition of international migration flows on affiliation to the Protestant Church. Our findings suggest that in the absence of compensatory flows, the Protestant Church will keep shrinking unless it manages to stop disaffiliation. The projections also show that migrants, especially within mobile Europe, are a potential source of members that is at present not properly contributing to membership in Austria. According to the TREND EUROPE scenario, which is – seen from today – the most likely scenario with a continuation of declining entries and increased exits, the Protestant population in Austria would still decline from 283 thousand in 2018 to 144 thousand in 2048 (-49%). At the level of the three provinces, the decline would be faster in Vienna (-42%, from 47 to 27 thousand) than in Burgenland (-26%, from 32 to 24 thousand) and Carinthia (-37%, from 48 to 30 thousand). According to this scenario, by 2048 the Protestant population would correspond to 1.5% of the total population of Austria(1.3% in Vienna, 7.3% in Burgenland and 5.4% in Carinthia). Other scenarios reflect the potential impact of different religious composition of future migrant flows, as well as changing disaffiliation patterns. Only under the LIFT scenario, which assumes a reduction in exits by 50% and more migrants enrolling to the Protestant Church, we see an end of the haemorrhage and even an increase in the number of Protestants in Vienna
Negative quantum capacitance in graphene nanoribbons with lateral gates
We present numerical simulations of the capacitive coupling between graphene
nanoribbons of various widths and gate electrodes in different configurations.
We compare the influence of lateral metallic or graphene side gate structures
on the overall back gate capacitive coupling. Most interestingly, we find a
complex interplay between quantum capacitance effects in the graphene
nanoribbon and the lateral graphene side gates, giving rise to an
unconventional negative quantum capacitance. The emerging non-linear capacitive
couplings are investigated in detail. The experimentally relevant relative
lever arm, the ratio between the coupling of the different gate structures, is
discussed.Comment: 8 pages, 6 figure
Meteorological application of Apollo photography Final report
Development of meteorological information and parameters based on cloud photographs taken during Apollo 9 fligh
Solid State NMR Characterization of Complex Metal Hydrides systems for Hydrogen Storage Applications
Solid state NMR is widely applied in studies of solid state chemistries for hydrogen storage reactions. Use of ^(11)B
MAS NMR in studies of metal borohydrides (BH_4) is mainly focused, revisiting the issue of dodecaborane formation
and observation of ^(11)B{^1H} Nuclear Overhauser Effect
Dewetting of thin polymer films near the glass transition
Dewetting of ultra-thin polymer films near the glass transition exhibits
unexpected front morphologies [G. Reiter, Phys. Rev. Lett., 87, 186101 (2001)].
We present here the first theoretical attempt to understand these features,
focusing on the shear-thinning behaviour of these films. We analyse the profile
of the dewetting film, and characterize the time evolution of the dry region
radius, , and of the rim height, . After a transient time
depending on the initial thickness, grows like while
increases like . Different regimes of growth are
expected, depending on the initial film thickness and experimental time range.Comment: 4 pages, 5 figures Revised version, published in Physical Review
Letters: F. Saulnier, E. Raphael and P.-G. de Gennes, Phys. Rev. Lett. 88,
196101 (2002
Improved Cardiorespiratory Fitness Is Associated with Increased Cortical Thickness in Mild Cognitive Impairment
Cortical atrophy is a biomarker of Alzheimer’s disease (AD) that correlates with clinical symptoms. This study examined changes in cortical thickness from before to after an exercise intervention in mild cognitive impairment (MCI) and healthy elders. Thirty physically inactive older adults (14 MCI, 16 healthy controls) underwent MRI before and after participating in a 12-week moderate intensity walking intervention. Participants were between the ages of 61 and 88. Change in cardiorespiratory fitness was assessed using residualized scores of the peak rate of oxygen consumption (V̇O2peak) from pre- to post-intervention. Structural magnetic resonance images were processed using FreeSurfer v5.1.0. V̇O2peak increased an average of 8.49%, which was comparable between MCI and healthy elders. Overall, cortical thickness was stable except for a significant decrease in the right fusiform gyrus in both groups. However, improvement in cardiorespiratory fitness due to the intervention (V̇O2peak) was positively correlated with cortical thickness change in the bilateral insula, precentral gyri, precuneus, posterior cingulate, and inferior and superior frontal cortices. Moreover, MCI participants exhibited stronger positive correlations compared to healthy elders in the left insula and superior temporal gyrus. A 12-week moderate intensity walking intervention led to significantly improved fitness in both MCI and healthy elders. Improved V̇O2peak was associated with widespread increased cortical thickness, which was similar between MCI and healthy elders. Thus, regular exercise may be an especially beneficial intervention to counteract cortical atrophy in all risk groups, and may provide protection against future cognitive decline in both healthy elders and MCI
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