248 research outputs found
Phase separation in coupled chaotic maps on fractal networks
The phase ordering dynamics of coupled chaotic maps on fractal networks are
investigated. The statistical properties of the systems are characterized by
means of the persistence probability of equivalent spin variables that define
the phases. The persistence saturates and phase domains freeze for all values
of the coupling parameter as a consequence of the fractal structure of the
networks, in contrast to the phase transition behavior previously observed in
regular Euclidean lattices. Several discontinuities and other features found in
the saturation persistence curve as a function of the coupling are explained in
terms of changes of stability of local phase configurations on the fractals.Comment: (4 pages, 4 Figs, Submitted to PRE
Dynamics of Coupling Functions in Globally Coupled Maps: Size, Periodicity and Stability of Clusters
It is shown how different globally coupled map systems can be analyzed under
a common framework by focusing on the dynamics of their respective global
coupling functions. We investigate how the functional form of the coupling
determines the formation of clusters in a globally coupled map system and the
resulting periodicity of the global interaction. The allowed distributions of
elements among periodic clusters is also found to depend on the functional form
of the coupling. Through the analogy between globally coupled maps and a single
driven map, the clustering behavior of the former systems can be characterized.
By using this analogy, the dynamics of periodic clusters in systems displaying
a constant global coupling are predicted; and for a particular family of
coupling functions, it is shown that the stability condition of these clustered
states can straightforwardly be derived.Comment: 12 pp, 5 figs, to appear in PR
Illicit drugs consumption evaluation by wastewater-based epidemiology in the urban area of Palermo city (Italy)
Introduction. A wastewater-based epidemiology approach was performed to estimate the drug consumption in Palermo city, the fifth largest city of Italy with a population of 671 696 inhabitants, and to investigate the monthly variability of drug loads in wastewater from different areas of the city. A seven-months detection campaign was conducted at the two wastewater treatment plants of the city. Methods. Following a pre-treatment, 32 samples of wastewater were analyzed by liquid chromatography-tandem mass spectrometry. Results. We estimated a mean cocaine use in Palermo of 0.19 g/day/1000 people, corresponding to 1.90 doses/1000 people and cannabinoids use of 2.85 g/day/1000 people, corresponding to 35.62 doses/1000 people. Amphetamines residues in wastewater were always recovered in concentrations lower than the limit of quantification. Conclusion. Our findings showed that drugs consumption in Palermo is in line with those of other Italian cities and that no significant differences on prevalence on cocaine and cannabinoids consumption were recorded in the different months of the survey, except for the summer period in a wastewater treatment plant of the city
Emergence of patterns in driven and in autonomous spatiotemporal systems
The relationship between a driven extended system and an autonomous
spatiotemporal system is investigated in the context of coupled map lattice
models. Specifically, a locally coupled map lattice subjected to an external
drive is compared to a coupled map system with similar local couplings plus a
global interaction. It is shown that, under some conditions, the emergent
patterns in both systems are analogous. Based on the knowledge of the dynamical
responses of the driven lattice, we present a method that allows the prediction
of parameter values for the emergence of ordered spatiotemporal patterns in a
class of coupled map systems having local coupling and general forms of global
interactions.Comment: 7 pages, 3 figs, submitted to PRE (2002
Comportamento e controle do gafanhoto RHAMMATOCERUS SCHISTOCERCOIDES (REHN, 1906) no Mato Grosso.
- Ern setembro de 1984, verificou-se uma explosão populacional da especie do gafanhoto Rhammatocerus schistocercoides (Rehn, 1906) no estado de Mato Grosso. 0 estudo da biologia em condicoes de laboratorio, casa de vegetario e campo revelou que a postura ocorre ern outubro-novembro e as ninfas emergern ern novembro-dezembro. Cada instar tem, em media, 26 dias, havendo cinco instares nas condicoes de Mato Grosso e seis instares nas condicoes do Distrito Federal. Transformarn-se ern adultos ern abril, n-ligratn ern agosto-setembro, e o acasalamento ocorre em setembro-outubro. Preferência alimentar: 0 R. schistocercoides prefere, ern primeiro lugar, gramineas nativas do cerrado e campo sujo, seguindo-se as culturas de arroz, cana-de-acucar, milho, sorgo, pastagens e, por firn, soja e feijão. Controle quimico: Foram testados para, o Controle do gafanhoto adulto os inseticidas: fenitrothion, malathion, carbaril, esfenvarelate e fenvarelate. 0 carbaril e os piretroides não foram eficientes nas clonagens testadas. 0 fenitrothion e o malathion mostraram acima de 98% da eficiencia nas dosagens de 300 g do i.a. e 800 g do i.a. por ha, respectivamente. Posteriormente se testou o fenitrothion dflufdo ern 61eo de algodão (50%), mostrando uma eficiência de 95% na dosagern de 150 g do La. por ha.Título em inglês: Behavior and control of the locust RHAMMATOCERUS SCHISTOCERCOIDES (REHN, 1906) in Mato Grosso, Brazil
La metodica wastewater based epidemiology come proxy di quantificazione del consumo di sostanze stupefacenti nella popolazione: l\u2019esperienza della citt\ue0 di Palermo.
INTRODUZIONE
Le istituzioni europee e la comunit\ue0 scientifica hanno, recentemente, definito un nuovo modello di sorveglianza attiva della potenziale diffusione delle droghe nella collettivit\ue0, la Wastewater Based Epidemiology (WBE), attraverso la ricerca analitica delle molecole e dei loro metaboliti nelle acque reflue cittadine. Lo scopo di questo lavoro \ue8 stato la valutazione di una preliminare applicazione di METODIca WBE nella citt\ue0 di Palermo, poco studiata in precedenti analisi a livello nazionale e internazionale.
METODI
Sono stati prelevati 28 campioni (2 litri cad) di refluo medio delle 24 ore in ingresso ai due depuratori di Palermo (WP1=45.000 ab. eq.; WP2=330.000 ab. eq.) in un periodo compreso tra giugno e novembre 2015. I campioni sono stati prefiltrati, concentrati ed infine analizzati (200 mml) mediante tecnica di spettrometria di massa LC-MS/MS. Gli analiti ricercati sono stati Cocaina, Benzoilecgonina (BEG), THC-COOH e Amfetamine (MDA, MDE, MDMA, Metamfetamine). \uc8 stato effettuato, inoltre, il calcolo della quantit\ue0 di sostanza stupefacente consumata nella popolazione (gr/die/1.000 abitanti e dosi/die/1.000 abitanti).
RISULTATI
I RISULTATI ottenuti sono illustrati nella tabella 1. I consumi di sostanze stupefacenti registrati nella citt\ue0 di Palermo (gr/die/1000 ab) sono RISULTATI i seguenti = Cocaina=0,145 (1,45 dosi/1000 ab); THC=4,37 (35,00 dosi/1000 ab), Amfetamine=Non quantificabili. CONCLUSIONI
L\u2019applicazione della metodologia WBE pu\uf2 essere considerata uno strumento aggiuntivo ai classici indicatori indiretti del consumo di droghe nella collettivit\ue0 a disposizione delle istituzioni per comprendere meglio il fenomeno delle tossicodipendenze e per attuare azioni di contrasto e politiche di educazione sanitaria pi\uf9 efficaci finalizzate alla prevenzione
Effect of noise on coupled chaotic systems
Effect of noise in inducing order on various chaotically evolving systems is
reviewed, with special emphasis on systems consisting of coupled chaotic
elements. In many situations it is observed that the uncoupled elements when
driven by identical noise, show synchronization phenomena where chaotic
trajectories exponentially converge towards a single noisy trajectory,
independent of the initial conditions. In a random neural network, with
infinite range coupling, chaos is suppressed due to noise and the system
evolves towards a fixed point. Spatiotemporal stochastic resonance phenomenon
has been observed in a square array of coupled threshold devices where a
temporal characteristic of the system resonates at a given noise strength. In a
chaotically evolving coupled map lattice with logistic map as local dynamics
and driven by identical noise at each site, we report that the number of
structures (a structure is a group of neighbouring lattice sites for whom
values of the variable follow certain predefined pattern) follow a power-law
decay with the length of the structure. An interesting phenomenon, which we
call stochastic coherence, is also reported in which the abundance and
lifetimes of these structures show characteristic peaks at some intermediate
noise strength.Comment: 21 page LaTeX file for text, 5 Postscript files for figure
Surface Energy Budgets of Arctic Tundra During Growing Season
This study analyzed summer observations of diurnal and seasonal surface energy budgets across several monitoring sites within the Arctic tundra underlain by permafrost. In these areas, latent and sensible heat fluxes have comparable magnitudes, and ground heat flux enters the subsurface during short summer intervals of the growing period, leading to seasonal thaw. The maximum entropy production (MEP) model was tested as an input and parameter parsimonious model of surface heat fluxes for the simulation of energy budgets of these permafrost‐underlain environments. Using net radiation, surface temperature, and a single parameter characterizing the thermal inertia of the heat exchanging surface, the MEP model estimates latent, sensible, and ground heat fluxes that agree closely with observations at five sites for which detailed flux data are available. The MEP potential evapotranspiration model reproduces estimates of the Penman‐Monteith potential evapotranspiration model that requires at least five input meteorological variables (net radiation, ground heat flux, air temperature, air humidity, and wind speed) and empirical parameters of surface resistance. The potential and challenges of MEP model application in sparsely monitored areas of the Arctic are discussed, highlighting the need for accurate measurements and constraints of ground heat flux.Plain Language SummaryGrowing season latent and sensible heat fluxes are nearly equal over the Arctic permafrost tundra regions. Persistent ground heat flux into the subsurface layer leads to seasonal thaw of the top permafrost layer. The maximum energy production model accurately estimates the latent, sensible, and ground heat flux of the surface energy budget of the Arctic permafrost regions.Key PointThe MEP model is parsimonious and well suited to modeling surface energy budget in data‐sparse permafrost environmentsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150560/1/jgrd55584.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150560/2/jgrd55584_am.pd
In vivo PET imaging of the neuroinflammatory response in rat spinal cord injury using the TSPO tracer [F-18]GE-180 and effect of docosahexaenoic acid
Centre for Trauma Sciences, funded by the Barts & The London Charity, GE Healthcare Ltd, the
Experimental Medicine Awards from the Blizard Institute and the Imaging Centre at the Barts Cancer Institute
Future Perspectives of Bone Tissue Engineering with Special Emphasis on Extracellular Vesicles
Peer reviewe
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