Freezing in random graph ferromagnets

Using T=0 Monte Carlo and simulated annealing simulation, we study the energy relaxation of ferromagnetic Ising and Potts models on random graphs. In addition to the expected exponential decay to a zero energy ground state, a range of connectivities for which there is power law relaxation and freezing to a metastable state is found. For some connectivities this freezing persists even using simulated annealing to find the ground state. The freezing is caused by dynamic frustration in the graphs, and is a feature of the local search-nature of the Monte Carlo dynamics used. The implications of the freezing on agent-based complex systems models are briefly considered.Comment: Published version: 1 reference deleted, 1 word added. 4 pages, 5 figure

Using quantitative dynamic adaptive policy pathways to manage climate change-induced coastal erosion

ABSTRACT: Adaptation requires planning strategies that consider the combined effect of climatic and non-climatic drivers, which are deeply uncertain. This uncertainty arises from many sources, cascades and accumulates in risk estimates. A prominent trend to incorporate this uncertainty in adaptation planning is through adaptive approaches such as the dynamic adaptive policy pathways (DAPP). We present a quantitative DAPP application for coastal erosion management to increase its utilisation in this field. We adopt an approach in which adaptation objectives and actions have continuous quantitative metrics that evolve over time as conditions change. The approach hinges on an adaptation information system that comprises hazard and impact modelling and systematic monitoring to assess changing risks and adaptation signals in the light of adaptation pathway choices. Using an elaborated case study, we force a shoreline evolution model with waves and storm surges generated by means of stochastic modelling from 2010 to 2100, considering uncertainty in extreme weather events, climate variability and mean sea-level rise. We produce a new type of adaptation pathways map showing a set of 90-year probabilistic trajectories that link changing objectives (e.g., no adaptation, limit risk increase, avoid risk increase) and nourishment placement over time. This DAPP approach could be applied to other domains of climate change adaptation bringing a new perspective in adaptive planning under deep uncertainty.Alexandra Toimil acknowledges the financial support from the FENIX Project funded by the Government of Cantabria. This research was also funded by the Spanish Government through the grant RISKCOADAPT (BIA2017-89401-R)

New developments in the forecasting of monthly overnight stays in the North Region of Portugal

The Tourism sector is of strategic importance to the North Region of Portugal and is growing. Forecasting monthly overnight stays in this region is, therefore, a relevant problem. In this paper, we analyze data more recent than those considered in previous studies and use them to develop and compare several forecasting models and methods. We conclude that the best results are achieved by models based on a non-parametric approach not considered so far for these data, the singular spectrum analysis.publishe

Metazoários Parasitos De Lambari Astyanax Altiparanae, Coletados Do Rio Do Peixe, São Paulo, Sudeste Do Brasil

In March 2010, 44 specimens of Astyanax altiparanae Garutti & Britski, 2000, commonly known as “lambari do rabo amarelo”, collected from the Peixe river in the state of São Paulo, Brazil were analyzed. Out of these 44 fishes, 38 had at least one species of metazoan parasite. Fifteen metazoan parasites species were collected and identified: Urocleidoides trinidadensis, Diaphorocleidus kabatai, Diaphorocleidus orthodusus, Diaphorocleidus sp., Urocleidoides sp., Trinibaculum altiparanae, Gyrodactylus sp., Jainus hexops, Contracaecum sp., Procamallanus (Spirocamallanus) inopinatus, Vaigamus sp., Amplexibranchius bryconis, Ergasilus sp., Zonocotyloides haroltravassossi and Henneguya sp. Six species of parasites presented a prevalence of over 10%. Weight and length of fishes didn’t influence the parasitism. All parasites presented an aggregated distribution. The parasite community of Astyanax altiparanae from the Peixe river was characterized as having high richness and low uniformity. © 2016, Universidade Federal de Santa Maria. All rights reserved.46587688

Static Cylindrical Matter Shells

Static cylindrical shells composed of massive particles arising from matching of two different Levi-Civita space-times are studied for the shell satisfying either isotropic or anisotropic equation of state. We find that these solutions satisfy the energy conditions for certain ranges of the parameters.Comment: 9 pages, 3 figures, Latex; Final version, To appear in General Relativity and Gravitatio

Demonstrating the Feasibility of Line Intensity Mapping Using Mock Data of Galaxy Clustering from Simulations

Visbal & Loeb (2010) have shown that it is possible to measure the clustering of galaxies by cross correlating the cumulative emission from two different spectral lines which originate at the same redshift. Through this cross correlation, one can study galaxies which are too faint to be individually resolved. This technique, known as intensity mapping, is a promising probe of the global properties of high redshift galaxies. Here, we test the feasibility of such measurements with synthetic data generated from cosmological dark matter simulations. We use a simple prescription for associating galaxies with dark matter halos and create a realization of emitted radiation as a function of angular position and wavelength over a patch of the sky. This is then used to create synthetic data for two different hypothetical instruments, one aboard the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) and another consisting of a pair of ground based radio telescopes designed to measure the CO(1-0) and CO(2-1) emission lines. We find that the line cross power spectrum can be measured accurately from the synthetic data with errors consistent with the analytical prediction of Visbal & Loeb (2010). Removal of astronomical backgrounds and masking bright line emission from foreground contaminating galaxies do not prevent accurate cross power spectrum measurements.Comment: 12 pages, 6 figures, Submitted to JCA

Glauber dynamics in a single-chain magnet: From theory to real systems

The Glauber dynamics is studied in a single-chain magnet. As predicted, a single relaxation mode of the magnetization is found. Above 2.7 K, the thermally activated relaxation time is mainly governed by the effect of magnetic correlations and the energy barrier experienced by each magnetic unit. This result is in perfect agreement with independent thermodynamical measurements. Below 2.7 K, a crossover towards a relaxation regime is observed that is interpreted as the manifestation of finite-size effects. The temperature dependences of the relaxation time and of the magnetic susceptibility reveal the importance of the boundary conditions.Comment: Submitted to PRL 10 May 2003. Submitted to PRB 12 December 2003; published 15 April 200

Assessment of time limit at lowest speed corresponding to maximal oxygen consumption in the four competitive swimming strokes

Time limit at lowest speed of maximal oxygen consumption (TLim-v O2max) was characterized in the 4 swimming strokes, and related with O2max and anaerobic threshold (AnT). 23 elite swimmers performed an incremental protocol for v O2max assessment. 48 hours later, Tlim-v O2max was assessed. O2 was directly measured BxB (K4 b2, Cosmed, Italy) and AnT was assessed individually (YSI 1500L Sport, USA). Tlim-v O2max values were 238.8±39.0, 246.1±51.9, 277.6±85.6 and 331.4±82.7 s in crawl, backstroke, butterfly, and breaststroke (no differences observed). No correlations were found between Tlim-v O2max and O2max, and AnT. However, inverse relationships were observed between Tlim-v O2max and v O2max (r=-0.63, p<0.01) and vAnT (r=-0.52, p=0.01), pointing out that the higher the velocities commonly related to aerobic proficiency, the lower the TLim- v O2max