Search results for "Variable length"
showing 10 items of 14 documents
Morphological investigation of the deep pineal of the rat.
1980
The results presented here reveal that in adult Sprague-Dawley and Wistar rats the pineal gland represents a complex rather than a single organ. Regularly one can distinguish (i) pineal tissue in the intercommissural region as a deep pineal, (ii) a superficial pineal, which represents the major part of the pineal complex, and (iii) nearly always a parenchymal stalk of variable length. The volume of the deep pineal with the adjacent parenchymal stalk exhibits great interindividual variation. It amounts to 127 +/- 39 X 10(5) mum3 (mean +/- standard deviation). The histological appearance of the deep and superficial pineal tissue is fairly similar. The intrinsic cells of the deep and superfici…
The Magdalenian harpoons from the Iberian Mediterranean, based on pieces from Cova de les Cendres (Teulada-Moraira, Valencian region)
2012
Abstract Harpoons are one of the most characteristic implements of the Upper Magdalenian. However, morphologic differences in barbs and bases mark different regional traditions. This paper gives an account of the main features of harpoons in the Iberian Mediterranean, based on findings from Cova de les Cendres, and compares them with those found in other areas in Western Europe. The specificities of Mediterranean harpoons (a single range of barbs, variable length and number of barbs, and lack of hafting devices on the base) are considered in discussion of their potential functions and possible hafting systems.
Persistent random walks, variable length Markov chains and piecewise deterministic Markov processes *
2013
A classical random walk $(S_t, t\in\mathbb{N})$ is defined by $S_t:=\displaystyle\sum_{n=0}^t X_n$, where $(X_n)$ are i.i.d. When the increments $(X_n)_{n\in\mathbb{N}}$ are a one-order Markov chain, a short memory is introduced in the dynamics of $(S_t)$. This so-called "persistent" random walk is nolonger Markovian and, under suitable conditions, the rescaled process converges towards the integrated telegraph noise (ITN) as the time-scale and space-scale parameters tend to zero (see Herrmann and Vallois, 2010; Tapiero-Vallois, Tapiero-Vallois2}). The ITN process is effectively non-Markovian too. The aim is to consider persistent random walks $(S_t)$ whose increments are Markov chains with…
Design of new DNA-interactive agents by molecular docking and QSPR approach
2010
The design of new series of pyrrolo-pyrimidine derivatives, further annelated with a third heterocycle of different size, which also present several chain shape moieties of variable length and with different physico-chemical character, is reported. In this contribution we showed that the combination of docking-based and QSPR-based methods could lead to good models for ligand-DNA interaction prediction. By means of these computational approaches on 360 proposed inhibitors, we were able to select the most promising candidates as DNA-interactive drugs potentially endowed with antitumor activity.
Mechanical models of amplitude and frequency modulation
2005
This paper presents some mechanical models for amplitude and frequency modulation. The equations governing both modulations are deduced alongside some necessary approximations. Computer simulations of the models are carried out by using available educational software. Amplitude modulation is achieved by using a system of two weakly coupled pendulums, whereas the frequency modulation is obtained by using a pendulum of variable length. Under suitable conditions (small oscillations, appropriate initial conditions, etc) both types of modulation result in significantly accurate and visualized simulations.
Probability and algorithmics: a focus on some recent developments
2017
Jean-François Coeurjolly, Adeline Leclercq-Samson Eds.; International audience; This article presents different recent theoretical results illustrating the interactions between probability and algorithmics. These contributions deal with various topics: cellular automata and calculability, variable length Markov chains and persistent random walks, perfect sampling via coupling from the past. All of them involve discrete dynamics on complex random structures.; Cet article présente différents résultats récents de nature théorique illustrant les interactions entre probabilités et algorithmique. Ces contributions traitent de sujets variés : automates cellulaires et calculabilité, chaînes de Mark…
Context Trees, Variable Length Markov Chains and Dynamical Sources
2012
Infinite random sequences of letters can be viewed as stochastic chains or as strings produced by a source, in the sense of information theory. The relationship between Variable Length Markov Chains (VLMC) and probabilistic dynamical sources is studied. We establish a probabilistic frame for context trees and VLMC and we prove that any VLMC is a dynamical source for which we explicitly build the mapping. On two examples, the "comb" and the "bamboo blossom", we find a necessary and sufficient condition for the existence and the uniqueness of a stationary probability measure for the VLMC. These two examples are detailed in order to provide the associated Dirichlet series as well as the genera…
Recursion at the crossroads of sequence modeling, random trees, stochastic algorithms and martingales
2013
This monograph synthesizes several studies spanning from dynamical systems in the statistical analysis of sequences, to analysis of algorithms in random trees and discrete stochastic processes. These works find applications in various fields ranging from biological sequences to linear regression models, branching processes, through functional statistics and estimates of risk indicators for insurances. All the established results use, in one way or another, the recursive property of the structure under study, by highlighting invariants such as martingales, which are at the heart of this monograph, as tools as well as objects of study.
Variable Length Memory Chains: Characterization of stationary probability measures
2021
Variable Length Memory Chains (VLMC), which are generalizations of finite order Markov chains, turn out to be an essential tool to modelize random sequences in many domains, as well as an interesting object in contemporary probability theory. The question of the existence of stationary probability measures leads us to introduce a key combinatorial structure for words produced by a VLMC: the Longest Internal Suffix. This notion allows us to state a necessary and sufficient condition for a general VLMC to admit a unique invariant probability measure. This condition turns out to get a much simpler form for a subclass of VLMC: the stable VLMC. This natural subclass, unlike the general case, enj…
Subsidizing technology: how to succeed
2011
Examining the database of applications to the Regional Government of Valencia's Institute for Small and Medium-sized Industries (Spain) for subsidies to aid technological development in small and medium-sized enterprises, this study seeks to explain the approval or rejection and the success or failure of projects that look to receive state funding. The independent variables in the database are particularly concerned with reliance on path dependence. The variable length of membership of the Institute, the number of previous applications, technology level, or belonging to a particular geographical area relate to the accumulation of experience and correspond to the study hypotheses. The study …