7,010 research outputs found
H-Theorems from Autonomous Equations
The H-theorem is an extension of the Second Law to a time-sequence of states
that need not be equilibrium ones. In this paper we review and we rigorously
establish the connection with macroscopic autonomy.
If for a Hamiltonian dynamics for many particles, at all times the present
macrostate determines the future macrostate, then its entropy is non-decreasing
as a consequence of Liouville's theorem. That observation, made since long, is
here rigorously analyzed with special care to reconcile the application of
Liouville's theorem (for a finite number of particles) with the condition of
autonomous macroscopic evolution (sharp only in the limit of infinite scale
separation); and to evaluate the presumed necessity of a Markov property for
the macroscopic evolution.Comment: 13 pages; v1 -> v2: Sec. 1-2 considerably rewritten, minor
corrections in Sec. 3-
Freezing transitions in non-Fellerian particle systems
Non-Fellerian processes show phenomena that are unseen in standard
interacting particle systems. We consider freezing transitions in
one-dimensional non-Fellerian processes which are built from the abelian
sandpile additions to which in one case, spin flips are added, and in another
case, the so called anti-sandpile subtractions. In the first case and as a
function of the sandpile addition rate, there is a sharp transition from a
non-trivial invariant measure to the invariant measure of the sandpile process.
For the combination sandpile plus anti-sandpile, there is a sharp transition
from one frozen state to the other anti-stat
A nonequilibrium extension of the Clausius heat theorem
We generalize the Clausius (in)equality to overdamped mesoscopic and
macroscopic diffusions in the presence of nonconservative forces. In contrast
to previous frameworks, we use a decomposition scheme for heat which is based
on an exact variant of the Minimum Entropy Production Principle as obtained
from dynamical fluctuation theory. This new extended heat theorem holds true
for arbitrary driving and does not require assumptions of local or close to
equilibrium. The argument remains exactly intact for diffusing fields where the
fields correspond to macroscopic profiles of interacting particles under
hydrodynamic fluctuations. We also show that the change of Shannon entropy is
related to the antisymmetric part under a modified time-reversal of the
time-integrated entropy flux.Comment: 23 pages; v2: manuscript significantly extende
De ontwikkeling van een nieuw meetvaartuig voor snelle lodingen in de Noordzee: het B.E.A.S.A.C.-project
Health advantages of transition to batch management system in farrow-to-finish pig herds
Sow batch management systems have become more popular due to advantages in labour planning, piglet batch sizes, all-in all-out practices and health management. The present study investigated the potential health advantages of 10 selected farrow-to-finish pig herds before and after transition from a one week batch management system to a four or five week batch management system. Five different animal categories (gilts, sows, piglets, growers and finishers) were sampled at three time points (T0, T1 and T2) before and after transition to a four or five week batch management system. Different matrices of the animals were collected: blood, nasal swabs and faeces. Several economically important diseases were monitored through serology: Lawsonia intracellularis, Porcine Reproductive and Respiratory Syndrome virus (PRRSv), Mycoplasma hyopneumoniae, Actinobacillus pleuropneurnoniae; and PCR-testing: Pasteurella multocida dermonecrotic toxin (DNT) and Brachyspira species, especially the major pathogenic Brachyspira hyodysenteriae. Following serological analysis, the percentage of positive animals per category and sampling occasion were calculated. Health improvement based on serology was defined as the reduction in the percentage of positive animals for a specific disease in a specified animal category. All samples were negative for P. multocida DNT and B. hyodysenteriae. Little to no improvement could be observed for PRRSv. For L. intracellularis an improvement could be observed in piglets (71%) and growers (56%; P < 0.05). For both of the respiratory pathogens, M. hyopneumoniae and A. pleuropneumoniae, significant improvement was observed in finishers (34 and 24%, respectively). In growers, only M. hyopneumoniae showed a significant improvement (34%). In conclusion, the transition from a one week batch management system to a four or five week batch management system in the present herds resulted in a reduction of the percentage of seropositive animals for three of the monitored economically important diseases: L. intracellularis, M. hyopneumoniae and A. pleuropneumoniae
Nonequilibrium Linear Response for Markov Dynamics, II: Inertial Dynamics
We continue our study of the linear response of a nonequilibrium system. This
Part II concentrates on models of open and driven inertial dynamics but the
structure and the interpretation of the result remain unchanged: the response
can be expressed as a sum of two temporal correlations in the unperturbed
system, one entropic, the other frenetic. The decomposition arises from the
(anti)symmetry under time-reversal on the level of the nonequilibrium action.
The response formula involves a statistical averaging over explicitly known
observables but, in contrast with the equilibrium situation, they depend on the
model dynamics in terms of an excess in dynamical activity. As an example, the
Einstein relation between mobility and diffusion constant is modified by a
correlation term between the position and the momentum of the particle
Illustrating answers: an evaluation of automatically retrieved illustrations of answers to medical questions
In this paper we discuss and evaluate a method for automatic text illustration, applied to answers to medical questions. Our method for selecting illustrations is based on the idea that similarities between the answers and picture-related text (the pictureâs caption or the section/paragraph that includes the picture) can be used as evidence that the picture would be appropriate to illustrate the answer.In a user study, participants rated answer presentations consisting of a textual component and a picture. The textual component was a manually written reference answer; the picture was automatically retrieved by measuring the similarity between the text and either the pictureâs caption or its section. The caption-based selection method resulted in more attractive presentations than the section-based method; the caption-based method was also more consistent in selecting informative pictures and showed a greater correlation between user-rated informativeness and the confidence of relevance of the system.When compared to manually selected pictures, we found that automatically selected pictures were rated similarly to decorative pictures, but worse than informative pictures
Production and evaluation of (multimodal) answers to medical questions
This paper describes two experiments carried out to investigate the production and evaluation of multimodal answer presentations in the context of a medical question answering system. In a production experiment participants had to produce answers to different types of questions. The results show that about one in four produced answers using multiple media. In an evaluation experiment, users had to evaluate different types of multimodal answer presentations. Answers with an informative visual were evaluated as more informative and more attractive than answers with a mere illustrative visual
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