1,602 research outputs found
Hard sphere-like dynamics in a non hard sphere liquid
The collective dynamics of liquid Gallium close to the melting point has been
studied using Inelastic X-ray Scattering to probe lengthscales smaller than the
size of the first coordination shell. %(momentum transfers, , 15
nm). Although the structural properties of this partially covalent
liquid strongly deviate from a simple hard-sphere model, the dynamics, as
reflected in the quasi-elastic scattering, are beautifully described within the
framework of the extended heat mode approximation of Enskog's kinetic theory,
analytically derived for a hard spheres system. The present work demonstrates
the applicability of Enskog's theory to non hard- sphere and non simple
liquids.Comment: 5 pages, 2 figures, accepted in Phys. Rev. Let
Tunneling of polarized fermions in 3D double wells
We study the tunneling of a spin polarized Fermi gas in a three-dimensional
double well potential, focusing on the time dynamics starting from an initial
state in which there is an imbalance in the number of particles in the two
wells. Although fermions in different doublets of the double well tunnel with
different frequencies, we point out that (incoherent) oscillations of a large
number of particles can arise, as a consequence of the presence of transverse
degrees of freedom. Estimates of the doublet structure and of the occupation of
transverse eigenstates for a realistic experimental setup are provided.Comment: 10 pages, Typos corrected and figures changed - published in Laser
Physics, issue on the LPHYS'11 conference (Sarajevo, 2011
A Constraint Solver for Flexible Protein Models
This paper proposes the formalization and implementation of a novel class of constraints aimed at modeling problems related to placement of multi-body systems in the 3-dimensional space. Each multi-body is a system composed of body elements, connected by joint relationships and constrained by geometric properties. The emphasis of this investigation is the use of multi-body systems to model native conformations of protein structures---where each body represents an entity of the protein (e.g., an amino acid, a small peptide) and the geometric constraints are related to the spatial properties of the composing atoms. The paper explores the use of the proposed class of constraints to support a variety of different structural analysis of proteins, such as loop modeling and structure prediction.
The declarative nature of a constraint-based encoding provides elaboration tolerance and the ability to make use of any additional knowledge in the analysis studies. The filtering capabilities of the proposed constraints also allow to control the number of representative solutions that are withdrawn from the conformational space of the protein, by means of criteria driven by uniform distribution sampling principles. In this scenario it is possible to select the desired degree of precision and/or number of solutions. The filtering component automatically excludes configurations that violate the spatial and geometric properties of the composing multi-body system. The paper illustrates the implementation of a constraint solver based on the multi-body perspective and its empirical evaluation on protein structure analysis problems
Quantum Quenches in Integrable Field Theories
We study the non equilibrium time evolution of an integrable field theory in
1+1 dimensions after a sudden variation of a global parameter of the
Hamiltonian. For a class of quenches defined in the text, we compute the long
times limit of the one point function of a local operator as a series of form
factors. Even if some subtleties force us to handle this result with care,
there is a strong evidence that for long times the expectation value of any
local operator can be described by a generalized Gibbs ensemble with a
different effective temperature for each eigenmode
On the origin of the -transition in liquid Sulphur
Developing a novel experimental technique, we applied photon correlation
spectroscopy using infrared radiation in liquid Sulphur around ,
i.e. in the temperature range where an abrupt increase in viscosity by four
orders of magnitude is observed upon heating within few degrees. This allowed
us - overcoming photo-induced and absorption effects at visible wavelengths -
to reveal a chain relaxation process with characteristic time in the ms range.
These results do rehabilitate the validity of the Maxwell relation in Sulphur
from an apparent failure, allowing rationalizing the mechanical and
thermodynamic behavior of this system within a viscoelastic scenario.Comment: 5 pages, 4 eps figures, accepted in Phys. Rev. Let
One-dimensional fermionic systems after interaction quenches and their description by bosonic field theories
We show that the dynamics of quenches in one dimension far off equilibrium
can be described by power laws, but with exponents differing from the fully
renormalized ones at lowest energies. Instead they depend on the initial state
and its excitation energy. Furthermore, we found that for quenches to strong
interactions unexpected similarities between systems in one and in infinite
dimensions occur, indicating the dominance of local processes.Comment: This is a distinctly revised version which is focussed on the
description of the dynamics by bosonization technique
a consensus statement for the clinical use of the renal sodium glucose co transporter 2 inhibitor dapagliflozin in patients with type 2 diabetes mellitus
ABSTRACTIntroduction: The present review developed a clinical consensus based on a Delphi method on Dapagliflozin, a selective inhibitor of the renal sodium-glucose co-transporter-2 (SGLT2-I) in the treatment of patients with Type 2 diabetes mellitus.Areas covered: Panel members, using a 5-point scale, were asked to rate 9 statements on pharmakodinamic, mode of action on glycaemic and extra-glycaemic effects, and safety of dapaglifozin, Members also aimed to identify the patient most susceptible to the treatment with dapagliflozin .Expert commentary: Dapagliflozin is effective in lowering the plasma glucose concentration with a good safety profile. Dapagliflozin can be utilized in combination with all other antihyperglycaemic agents at all stages of the disease: however, a reduced GFR limits its efficacy. As for the other drugs of the class, Dapagliflozin positively modifies other risk factors for CV disease: these effects will be tested in the so far largest cardiovascular outcome trial for the SGLT2 inh..
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