Search results for "Adapta"
showing 10 items of 1961 documents
Bacterial endosymbionts of insects: insights from comparative genomics.
2004
The development of molecular techniques for the study of uncultured bacteria allowed the extensive study of the widespread association between insects and intracellular symbiotic bacteria. Most of the bacterial endosymbionts involved in such associations are gamma-proteobacteria, closely related to Escherichia coli. In recent years, five genomes from insect endosymbionts have been sequenced, allowing the performance of extensive genome comparative analysis that, as a complement of phylogenetic studies, and analysis on individual genes, can help to understand the different traits of this particular association, including how the symbiotic process is established, the explanation of the specia…
Dynamics of two competing species in the presence of Lévy noise sources
2010
We consider a Lotka-Volterra system of two competing species subject to multiplicative alpha-stable Lévy noise. The interaction parameter between the species is a random process which obeys a stochastic differential equation with a generalized bistable potential in the presence both of a periodic driving term and an additive alpha-stable Lévy noise. We study the species dynamics, which is characterized by two different regimes, exclusion of one species and coexistence of both. We find quasi-periodic oscillations and stochastic resonance phenomenon in the dynamics of the competing species, analysing the role of the Lévy noise sources.
Pulsed-Resource Dynamics Constrain the Evolution of Predator-Prey Interactions
2011
Although temporal variability in the physical environment plays a major role in population fluctuations, little is known about how it drives the ecological and evolutionary dynamics of species interactions. We studied experimentally how extrinsic resource pulses affect evolutionary and ecological dynamics between the prey bacterium Serratia marcescens and the predatory protozoan Tetrahymena thermophila. Predation increased the frequency of defensive, nonpigmented prey types, which bore competitive costs in terms of reduced maximum growth rate, most in a constant-resource environment. Furthermore, the predator densities of the pulsed-resource environment regularly fluctuated above and below …
Associations between success and failure in a face-to-face competition and psychobiological parameters in young women
2012
Within an evolutionary framework, in recent years some questions have been raised about whether women have a pattern of psychobiological response to social stress similar to that described in men. The main objective of this study was to analyze women's patterns of neuroendocrine, cardiovascular and mood responses to an individual competitive task, taking into account the outcome obtained. For this purpose, we measured salivary testosterone (T) and cortisol (C) levels, heart rate (HR) and blood pressure (BP), in addition to mood changes, in 40 healthy young women before, during and after a face-to-face laboratory competition. We also assessed some relevant psychological traits. Our results i…
RETROFITTING DETENTION BUILDINGS OF HISTORICAL-CULTURAL INTEREST. A CASE STUDY IN ITALY
2021
Penitentiary buildings in Italy include many buildings of undoubted historical and architectural importance. These have been, or will soon be, subject to structural changes necessary to adapt their spaces to the current regulations of prisons. The idea of punishment itself has changed over the centuries, so it is a physiological necessity to adapt existing buildings accordingly. When, however, such buildings date back centuries, they should not be considered a mere container but a historical testimony rich in meaning for the entire nation. The characteristics of the materials, distribution, and what these buildings have represented for the city should be the object of study and protection, …
Modeling and Performance Analysis of Channel Assembling in Multichannel Cognitive Radio Networks With Spectrum Adaptation
2012
[EN] To accommodate spectrum access in multichannel cognitive radio networks (CRNs), the channel-assembling technique, which combines several channels together as one channel, has been proposed in many medium access control (MAC) protocols. However, analytical models for CRNs enabled with this technique have not been thoroughly investigated. In this paper, two representative channel-assembling strategies that consider spectrum adaptation and heterogeneous traffic are proposed, and the performance of these strategies is evaluated based on the proposed continuous-time Markov chain (CTMC) models. Moreover, approximations of these models in the quasistationary regime are analyzed, and closed-fo…
Stackelberg-Cournot and Cournot equilibria in a mixed markets exchange economy
2012
In this note, we compare two strategic general equilibrium concepts: the Stackelberg-Cournot equilibrium and the Cournot equilibrium. We thus consider a market exchange economy including atoms and a continuum of traders, who behave strategically. We show that, when the preferences of the small traders are represented by Cobb-Douglas utility functions and the atoms have the same utility functions and endowments, the Stackelberg-Cournot and the Cournot equilibrium equilibria coincide if and only if the followers’ best responses functions have a zero slope at the SCE.
Switching synchronization in 1-D memristive networks: An exact solution
2017
We study a switching synchronization phenomenon taking place in one-dimensional memristive networks when the memristors switch from the high to low resistance state. It is assumed that the distributions of threshold voltages and switching rates of memristors are arbitrary. Using the Laplace transform, a set of non-linear equations describing the memristors dynamics is solved exactly, without any approximations. The time dependencies of memristances are found and it is shown that the voltage falls across memristors are proportional to their threshold voltages. A compact expression for the network switching time is derived.
Revisitation of Nonorthogonal Spin Adaptation in Coupled Cluster Theory.
2015
The benefits of what is alternatively called a nonorthogonally spin-adapted, spin-free, or orbital representation of the coupled cluster equations is discussed relative to orthogonally spin-adapted, spin-orbital, and spin-integrated theories. In particular, specific linear combinations of the orbital cluster amplitudes, denoted spin-summed amplitudes, are shown to reduce the number of contractions that must be explicitly performed and to simplify the expressions and their derivation. The computational efficiency of the spin-summed approach is discussed and compared to orthogonally spin-adapted and spin-integrated approaches. The spin-summed approach is shown to have significant computationa…
A self-adaptable distributed CBR version of the EquiVox system
2016
Three dimensional (3D) voxel phantoms are numerical representations of human bodies, used by physicians in very different contexts. In the controlled context of hospitals, where from 2 to 10 subjects may arrive per day, phantoms are used to verify computations before therapeutic exposure to radiation of cancerous tumors. In addition, 3D phantoms are used to diagnose the gravity of accidental exposure to radiation. In such cases, there may be from 10 to more than 1000 subjects to be diagnosed simultaneously. In all of these cases, computation accuracy depends on a single such representation. In this paper, we present EquiVox which is a tool composed of several distributed functions and enab…