2,661 research outputs found
On the concept of Bell's local causality in local classical and quantum theory
The aim of this paper is to give a sharp definition of Bell's notion of local
causality. To this end, first we unfold a framework, called local physical
theory, integrating probabilistic and spatiotemporal concepts. Formulating
local causality within this framework and classifying local physical theories
by whether they obey local primitive causality --- a property rendering the
dynamics of the theory causal, we then investigate what is needed for a local
physical theory, with or without local primitive causality, to be locally
causal. Finally, comparing Bell's local causality with the Common Cause
Principles and relating both to the Bell inequalities we find a nice
parallelism: Bell inequalities cannot be derived neither from local causality
nor from a common cause unless the local physical theory is classical or the
common cause is commuting, respectively.Comment: 24 pages, 5 figure
Point-contact spectroscopy of Al- and C-doped MgB2. Superconducting energy gaps and scattering studies
The two-band/two-gap superconductivity in aluminium and carbon doped MgB
has been addressed by the point-contact spectroscopy. Two gaps are preserved in
all samples with down to 22 K. The evolution of two gaps as a function
of the critical temperature in the doped systems suggest the dominance of the
band-filling effects but for the increased Al-doping the enhanced interband
scattering approaching two gaps must be considered. The magnetic field
dependences of the Andreev reflection excess currents as well as zero-energy
density of states determined from the experimental data are used to analyze the
intraband scattering. It is shown, that while the C-doping increases the
intraband scattering in the -band more rapidly then in the band,
the Al-doping does not change their relative weight.Comment: 8 pages, incl. 6 figure
BOOK REVIEW. Dario Bini and Victor Pan: Polynomial and Matrix Computations Volume I . Fundamental Algorithms
The key elements of conducting load-to-fracture mechanical testing on restoration-tooth units in restorative dentistry
Biomimetic restorative dentistry strives to replace lost tooth tissue by biomaterials with similar physical properties. In order to do so, mechanical testing of dental restorative materials on their own and later in dental cavities is highly important. During this process dentists and engineers are collaborating aiming to set the indications of certain restorative materials and application techniques. In vitro fracture resistance testing of a restored tooth is one of the most important tests to be carried out during the indication setting process. However, for this specific test and received results to be valid for clinicians, the group conducting the tests must pay attention to mimic intraoral conditions as much as possible. The article aims at identifying the key elements of fracture resistance tests in dentistry. Adequately conducting this test is a prerequisite for later testing in in vivo conditions the restorative techniques that produced the best results among the in vitro tests
Main-Belt Asteroids in the K2 Engineering Field of View
Unlike NASA's original Kepler Discovery Mission, the renewed K2 Mission will
stare at the plane of the Ecliptic, observing each field for approximately 75
days. This will bring new opportunities and challenges, in particular the
presence of a large number of main-belt asteroids that will contaminate the
photometry. The large pixel size makes K2 data susceptible to the effect of
apparent minor planet encounters. Here we investigate the effects of asteroid
encounters on photometric precision using a sub-sample of the K2 Engineering
data taken in February, 2014. We show examples of asteroid contamination to
facilitate their recognition and distinguish these events from other error
sources. We conclude that main-belt asteroids will have considerable effects on
K2 photometry of a large number of photometric targets during the Mission, that
will have to be taken into account. These results will be readily applicable
for future space photometric missions applying large-format CCDs, such as TESS
and PLATO.Comment: accepted for publication in AJ, 6 page
Kernel hardness and dough reological investigation on different wheat varieties
The aim of this research was the investigation of winter wheat varieties, the kernel hardness and the dough features. We determined the kernel hardness with two dynamic methods. We measured the parameters of flour. The correlations among hardness index and the examined flour parameters were also significant (r=0.816-0.876). We found strong correlation between the grinding energy (eg) and water absorption (r=0.878) of the flour. Hardness Index – wet gluten (r=0.833), and Hardness Index – water absorption (r=0.876), Hardness Index – P value of alveograph (r=0.816) showed also positive correlations. We found correlation the water absorption and P value of alveograph (r=0.873)
Bell's local causality is a d-separation criterion
This paper aims to motivate Bell's notion of local causality by means of
Bayesian networks. In a locally causal theory any superluminal correlation
should be screened off by atomic events localized in any so-called
\textit{shielder-off region} in the past of one of the correlating events. In a
Bayesian network any correlation between non-descendant random variables are
screened off by any so-called \textit{d-separating set} of variables. We will
argue that the shielder-off regions in the definition of local causality
conform in a well defined sense to the d-separating sets in Bayesian networks.Comment: 13 pages, 8 figure
Characterization of preclones by matrix collections
Preclones are described as the closed classes of the Galois connection
induced by a preservation relation between operations and matrix collections.
The Galois closed classes of matrix collections are also described by explicit
closure conditions.Comment: 11 page
- …