Critical dynamics of phase transition driven by dichotomous Markov noise

An Ising spin system under the critical temperature driven by a dichotomous Markov noise (magnetic field) with a finite correlation time is studied both numerically and theoretically. The order parameter exhibits a transition between two kinds of qualitatively different dynamics, symmetry-restoring and symmetry-breaking motions, as the noise intensity is changed. There exist regions called channels where the order parameter stays for a long time slightly above its critical noise intensity. Developing a phenomenological analysis of the dynamics, we investigate the distribution of the passage time through the channels and the power spectrum of the order parameter evolution. The results based on the phenomenological analysis turn out to be in quite good agreement with those of the numerical simulation.Comment: 27 pages, 12 figure

Influence of severe plastic deformation on the precipitation hardening of a FeSiTi steel

The combined strengthening effects of grain refinement and high precipitated volume fraction (~6at.%) on the mechanical properties of FeSiTi alloy subjected to SPD processing prior to aging treatment were investigated by atom probe tomography and scanning transmission electron microscopy. It was shown that the refinement of the microstructure affects the precipitation kinetics and the spatial distribution of the secondary hardening intermetallic phase, which was observed to nucleate heterogeneously on dislocations and sub-grain boundaries. It was revealed that alloys successively subjected to these two strengthening mechanisms exhibit a lower increase in mechanical strength than a simple estimation based on the summation of the two individual strengthening mechanisms

Determining flooded areas using crowd sensing data and weather radar precipitation : a case study in Brazil

Crowd sensing data (also known as crowdsourcing) are of great significance to support flood risk management. With the growing volume of available data in the past few years, researchers have used in situ sensor data to filter and prioritize volunteers’ information. Nevertheless, stationary, in situ sensors are only capable of monitoring a limited region, and this could hamper proper decision-making. This study investigates the use of weather radar precipitation to support the processing of crowd sensing data with the goal of improving situation awareness in a disaster and early warnings (e.g., floods). Results from a case study carried out in the city of São Paulo, Brazil, demonstrate that weather radar data are able to validate flooded areas identified from clusters of crowd sensing data. In this manner, crowd sensing and weather radar data together can not only help engage citizens, but also generate high-quality data at finer spatial and temporal resolutions to improve the decision-making related to weather-related disaster events

Revealing power dynamics and staging conflicts in agricultural system transitions : Case studies of innovation platforms in New Zealand

Innovation platforms (IPs) that support agricultural innovation to enable transition processes towards more sustainable agriculture provide a space where conflicts of interest among actors in the existing agricultural system (the so called incumbent regime) may play out. Sometimes these conflicts over how actors will benefit from an action are not revealed until actors are brought together. However, a barrier to change occurs when IP actors use their existing power to mobilise resources to influence if and how individual and collective interests are aligned. In the context of agricultural innovation and transitions, this paper uses the power in transitions framework (Avelino and Wittmayer, 2016), along with analytical perspectives on conflicts and role perceptions, to understand how consciously staging or revealing conflicts of interest among IP actors changed role perceptions and power relations among these actors. The paper explores this topic in two IPs addressing agricultural production and sustainability challenges in New Zealand's agricultural sector. Conflicts were staged in IPs when one group of actors mobilised resources that enabled them to move existing power relations from one-sided, to synergistic or a mutual dependency. This enabled conflicts to be acknowledged and solved. In contrast, conflicts were not staged when actors mobilised resources to maintain antagonostic power relations. Our cases demontrate that staging conflicts to change actors' role perceptions is an important intermediary step to forming new power relations in the agricultural system. Our findings highlight the need for IP theory to conceptualise power relations in IPs as context specific, dynamic and a force shaping outcomes, rather than solely a force exerted by actors in the incumbent regime over IP actors.</p

Fluctuating dynamics at the quasiperiodic onset of chaos, Tsallis q-statistics and Mori's q-phase thermodynamics

We analyze the fluctuating dynamics at the golden-mean transition to chaos in the critical circle map and find that trajectories within the critical attractor consist of infinite sets of power laws mixed together. We elucidate this structure assisted by known renormalization group (RG) results. Next we proceed to weigh the new findings against Tsallis' entropic and Mori's thermodynamic theoretical schemes and observe behavior to a large extent richer than previously reported. We find that the sensitivity to initial conditions has the form of families of intertwined q-exponentials, of which we determine the q-indexes and the generalized Lyapunov coefficient spectra. Further, the dynamics within the critical attractor is found to consist of not one but a collection of Mori's q-phase transitions with a hierarchical structure. The value of Mori's `thermodynamic field' variable q at each transition corresponds to the same special value for the entropic index q. We discuss the relationship between the two formalisms and indicate the usefulness of the methods involved to determine the universal trajectory scaling function and/or the ocurrence and characterization of dynamical phase transitions.Comment: Resubmitted to Physical Review E. The title has been changed slightly and the abstract has been extended. There is a new subsection following the conclusions that explains the role and usefulness of the q-statistics in the problem studied. Other minor changes througout the tex

A recent appreciation of the singular dynamics at the edge of chaos

We study the dynamics of iterates at the transition to chaos in the logistic map and find that it is constituted by an infinite family of Mori's $q$-phase transitions. Starting from Feigenbaum's $\sigma$ function for the diameters ratio, we determine the atypical weak sensitivity to initial conditions $\xi _{t}$ associated to each $q$-phase transition and find that it obeys the form suggested by the Tsallis statistics. The specific values of the variable $q$ at which the $q$-phase transitions take place are identified with the specific values for the Tsallis entropic index $q$ in the corresponding $\xi_{t}$. We describe too the bifurcation gap induced by external noise and show that its properties exhibit the characteristic elements of glassy dynamics close to vitrification in supercooled liquids, e.g. two-step relaxation, aging and a relationship between relaxation time and entropy.Comment: Proceedings of: Verhulst 200 on Chaos, Brussels 16-18 September 2004, Springer Verlag, in pres

Incidence of nonextensive thermodynamics in temporal scaling at Feigenbaum points

Recently, in Phys. Rev. Lett. 95, 140601 (2005), P. Grassberger addresses the interesting issue of the applicability of q-statistics to the renowned Feigenbaum attractor. He concludes there is no genuine connection between the dynamics at the critical attractor and the generalized statistics and argues against its usefulness and correctness. Yet, several points are not in line with our current knowledge, nor are his interpretations. We refer here only to the dynamics on the attractor to point out that a correct reading of recent developments invalidates his basic claim.Comment: To be published in Physica

A service-oriented middleware for integrated management of crowdsourced and sensor data streams in disaster management

The increasing number of sensors used in diverse applications has provided a massive number of continuous, unbounded, rapid data and requires the management of distinct protocols, interfaces and intermittent connections. As traditional sensor networks are error-prone and difficult to maintain, the study highlights the emerging role of “citizens as sensors” as a complementary data source to increase public awareness. To this end, an interoperable, reusable middleware for managing spatial, temporal, and thematic data using Sensor Web Enablement initiative services and a processing engine was designed, implemented, and deployed. The study found that its approach provided effective sensor data-stream access, publication, and filtering in dynamic scenarios such as disaster management, as well as it enables batch and stream management integration. Also, an interoperability analytics testing of a flood citizen observatory highlighted even variable data such as those provided by the crowd can be integrated with sensor data stream. Our approach, thus, offers a mean to improve near-real-time applications

EFECTO DEL GENOTIPO ANIMAL SOBRE EL RENDIMIENTO DE LA RES Y CALIDAD DE LA CARNE DE NOVILLOS ALIMENTADOS SOBRE PASTURA Y SUPLEMENTADOS EN EL PERIODO INVERNAL

El estudio fue realizado con el objetivo de determinar el rendimiento de la res y caracterizar la calidad de carne de cuatro genotipos de bovino de carne. Fueron extraídos al azar cuatro cabezas de un total de 30 animales terminados por tratamiento, sometidos a similares condiciones de manejo, sanidad y alimentación, con edad promedio de 24 meses. Los tratamientos fueron: Criollo (Cr, Bos taurus adaptado), Indico (1, Bos indicus), Trihíbrido (Tr, Bos taurus adaptado x Bos indicus x Bos taurus continental) e Híbrido (H, Bos taurus ingles x Bos indicus). El Diseño experimental fue el de bloques completos al azar, los resultados obtenidos fueron sometidos a ANAVA, las diferencias fueron analizadas por el test de Tukey al 5%. Los resultados evidencian pesos superiores de los H y Tr (sin ayuno) con respecto al Cr, mientras con ayuno solamente el H fue estadísticamente superior al Cr. Los tratamientos H, Tre I fueron estadísticamente superiores en el rendimiento en peso de la res al Cr. Los rendimientos como porcentaje del peso vivo sin y con ayuno promediaron 52.3 y 56.3 %, resp. El desbaste promedio fué de 7 %. Los tratamientos H y Tr fueron superiores al Cr en relación al cuarto pistola corto y paleta+costillar, los mismos no arrojaron diferencia como porcentaje del peso vivo sin y con ayuno. El residuo blando y el residuo duro representan el 17.1 y e113.5 % del peso vivo sin ayuno. En cuanto a la calidad de carne los parámetros espesor de grasa y color de carne presentaron diferencias estadísticas, siendo el Cr superior a los demás tratamientos (6 mm y grado 5, resp.), no se encontró diferencias en los otros parámetros. El marmoreado obtenido fue pobre, aunque el color de carne y de grasa se cualificó como muy buena (Según Standard Japonés). Los pesos de cortes de lomito (Psoas mayor) y peceto (Semitendinosus) están en relación directa a los pesos vivos de los animales de cada tratamiento (H&gt;Tr&gt;I&gt;Cr), encontrándose diferencia estadística solamente en el peceto entre H y Cr.