44,098 research outputs found
Exact Recovery for a Family of Community-Detection Generative Models
Generative models for networks with communities have been studied extensively
for being a fertile ground to establish information-theoretic and computational
thresholds. In this paper we propose a new toy model for planted generative
models called planted Random Energy Model (REM), inspired by Derrida's REM. For
this model we provide the asymptotic behaviour of the probability of error for
the maximum likelihood estimator and hence the exact recovery threshold. As an
application, we further consider the 2 non-equally sized community Weighted
Stochastic Block Model (2-WSBM) on -uniform hypergraphs, that is equivalent
to the P-REM on both sides of the spectrum, for high and low edge cardinality
. We provide upper and lower bounds for the exact recoverability for any
, mapping these problems to the aforementioned P-REM. To the best of our
knowledge these are the first consistency results for the 2-WSBM on graphs and
on hypergraphs with non-equally sized community
Medical use of cannabis: italian and european legislation
This review illustrates some brief
considerations of the medical use of cannabis recently
issued in Italy. History and uses of cannabis
throughout centuries and different countries
are illustrated together with a description of botany
and active phytocannabinoids. Then, medical
use of cannabis anti-pain treatment for patients
resistant to conventional therapies is described
in case of chronic neuropathic pain, spasticity,
for anticinetosic and antiemetic effect in nausea
and vomiting caused by chemotherapy, for appetite
stimulating effect in cachexia, anorexia, loss
of appetite in cancer patients or patients with
AIDS and in anorexia nervosa, hypotensive effect
in glaucoma resistant to conventional therapies
and for reduction of involuntary body and facial
movements in Gilles de la Tourette syndrome.
Italian most recent legislation on medical cannabis
is detailed with some law proposals, also
showing the inconsistent legislation within European
Union. Some final considerations of future
studies are also reported
X-ray ionization of the intergalactic medium by quasars
We investigate the impact of quasars on the ionization of the surrounding
intergalactic medium (IGM) with the radiative transfer code \texttt{CRASH4},
now accounting for X-rays and secondary electrons. After comparing with
analytic solutions, we post-process a cosmic volume (
Mpc) containing a ULAS J1120+0641-like quasar (QSO) hosted by a dark matter (DM) halo. We find that: (i)
the average HII region (~pMpc in a lifetime ~yrs) is
mainly set by UV flux, in agreement with semi-analytic scaling relations; (ii)
a largely neutral (), warm (~K) tail
extends up to few Mpc beyond the ionization front, as a result of the X-ray
flux; (iii) LyC-opaque inhomogeneities induce a line of sight (LOS) scatter in
as high as few physical Mpc, consistent with the DLA scenario proposed to
explain the anomalous size of the ULAS J1120+0641 ionized region. On the other
hand, with an ionization rate ~s, the
assumed DLA clustering and gas opacity, only one LOS shows an HII region
compatible with the observed one. We deduce that either the ionization rate of
the QSO is at least one order of magnitude lower or the ULAS J1120+0641 bright
phase is shorter than ~yrs.Comment: Accepted for publication in MNRAS Main Journal, Accepted 2018 May 2
Strengthening gold-gold bonds by complexing gold clusters with noble gases
We report an unexpectedly strong and complex chemical bonding of rare-gas
atoms to neutral gold clusters. The bonding features are consistently
reproduced at different levels of approximation within density-functional
theory and beyond: from GGA, through hybrid and double-hybrid functionals, up
to renormalized second-order perturbation theory. The main finding is that the
adsorption of Ar, Kr, and Xe reduces electron-electron repulsion within gold
dimer, causing strengthening of the Au-Au bond. Differently from the dimer, the
rare-gas adsorption effects on the gold trimer's geometry and vibrational
frequencies are mainly due to electron occupation of the trimer's lowest
unoccupied molecular orbital. For the trimer, the theoretical results are also
consistent with far-infrared multiple photon dissociation experiments.Comment: To be published in Inorganic Chemistry Communication
On a problem of Pillai with k-generalized Fibonacci numbers and powers of 2
For an integer , let be the --generalized Fibonacci sequence which starts with ( terms) and each term afterwards is the sum of the preceding terms. In this paper, we find all integers having at least two presentations as a difference between a --generalized Fibonacci number and a powers of 2 for any fixed . This paper extends previous work from [9] for the case and [6] for the case
Spontaneous breaking of conformal invariance in theories of conformally coupled matter and Weyl gravity
We study the theory of Weyl conformal gravity with matter degrees of freedom
in a conformally invariant interaction. Specifically, we consider a triplet of
scalar fields and SO(3) non-abelian gauge fields, i.e. the Georgi-Glashow model
conformally coupled to Weyl gravity. We show that the equations of motion admit
solutions spontaneously breaking the conformal symmetry and the gauge symmetry,
providing a mechanism for supplying a scale in the theory. The vacuum solution
corresponds to anti-de-Sitter space-time, while localized soliton solutions
correspond to magnetic monopoles in asymptotically anti-de-Sitter space-time.
The resulting effective action gives rise to Einstein gravity and the residual
U(1) gauge theory. This mechanism strengthens the reasons for considering
conformally invariant matter-gravity theory, which has shown promising
indications concerning the problem of missing matter in galactic rotation
curves.Comment: 20 pages, 1 figure, revised and added reference
Universality of the Tearing Phase in Matrix Models
The spontaneous symmetry breaking associated to the tearing of a random
surface, where large dynamical holes fill the surface, was recently analized
obtaining a non-universal critical exponent on a border phase. Here the issue
of universality is explained by an independent analysis. The one hole sector of
the model is useful to manifest the origin of the (limited) non-universal
behaviour, that is the existence of two inequivalent critical points.Comment: 9 pages, 1 figure non include
An LTL Semantics of Business Workflows with Recovery
We describe a business workflow case study with abnormal behavior management
(i.e. recovery) and demonstrate how temporal logics and model checking can
provide a methodology to iteratively revise the design and obtain a correct-by
construction system. To do so we define a formal semantics by giving a
compilation of generic workflow patterns into LTL and we use the bound model
checker Zot to prove specific properties and requirements validity. The working
assumption is that such a lightweight approach would easily fit into processes
that are already in place without the need for a radical change of procedures,
tools and people's attitudes. The complexity of formalisms and invasiveness of
methods have been demonstrated to be one of the major drawback and obstacle for
deployment of formal engineering techniques into mundane projects
- …