Equilibrium Times for the Multicanonical Method

This work measures the time to equilibrium for the multicanonical method on the 2D-Ising system by using a new criterion, proposed here, to find the time to equilibrium, teq, of any sampling procedure based on a Markov process. Our new procedure gives the same results that the usual one, based on the magnetization, for the canonical Metropolis sampling on a 2D-Ising model at several temperatures. For the multicanonical method we found a power-law relationship with the system size, L, of teq=0.27(15) L^2.80(13), and with the number of energy levels to explore, kE, of teq=0.7(13) kE^1.40(11), in perfect agreement with the result just above. In addition, some kind of critical slowing down was observed around the critical energy. Our new procedure is completely general, and can be applied to any sampling method based on a Markov process.Comment: 7 pages, 5 eps figures, to be published in Int. J. Mod. Phys.

Environmental Effects on Cephalopod Life History and Fisheries

Editorial de un número especial de la Revista Aquatic Living ResourcesThe present collection of papers arises from a theme session on “Cephalopod Stocks: Review, Analyses, Assessment, and Sustainable Management” at the 2004 ICES Annual Science Conference, Vigo, Spain. The original proposal for the theme session was justified by the availability of much unpublished information on cephalopod biology and fisheries arising from various CEC-funded R&D projects during the last 15 years. The theme session also related directly to the EC-funded Concerted Action: CEPHSTOCK (Q5CA-2002-00962), and provided a route for dissemination of the review and synthesis work carried out under this project. The theme session was intended to facilitate the wider dissemination and publication of these results, with the long-term aim of informing future management decisions for the major fished stocks of cephalopods in European waters. Any future European research programme, related to cephalopod biology and fisheries, will need to take into account of knowledge acquired on cephalopod populations. The theme session aimed to attract scientists working on cephalopod stocks outside the NE Atlantic as well as those from ICES countries. The scope of the theme session was: • The current state of knowledge on exploited cephalopods (biology, fisheries, environmental relationships, stock identity) in European waters; • Current fishery data collection, stock assessment and management practices for cephalopod capture fisheries world-wide; • The current status of cephalopod culture and the prospects for commercial aquaculture; • Socio-economic issues related to cephalopod fisheries; • Current knowledge of aspects of cephalopod biology and ecology related to their suitability as resource species for capture and culture fisheries, and assessment of environmental factors which affect the immuno-competence and physiology of cephalopods; • Assessment and management options for currently unregulated cephalopod fisheries. The theme session attracted 28 oral presentations and 12 posters that could be broadly divided into those more concerned with biology and ecology, and those focusing on fisheries. Some of these presentations appear elsewhere, e.g. Guerra et al. (2005) on giant squid strandings. The selection of papers presented in Aquatic Living Resources vol. 18, No. 4, 2005, “Environmental effects on cephalopod life history and fisheries”, illustrates how cephalopod studies could contribute to a development of an ecosystem approach to fisheries management (FAO 2003), by analysing a series of environmental effects operating at different scales. Environmental effects on life histories The life-cycle characteristics of cephalopods contribute the main reasons for the large inter-annual fluctuations of population densities (Boyle and Boletzky 1996). In teleost fishes differences in biological parameters have been analysed in relation to fishing, considered sometimes as the main environmental impact (Rochet et al. 2000). As a first step to transposing this approach to cephalopods, substantial biological data sets and new statistical approaches are applied to answer questions about squid life history. Vidal et al. evaluated the influence of food supply on yolk utilization, metabolism and growth of paralarvae of Loligo vulgaris reynaudii while Smith et al. re-examined historical life history data to infer the relationships between nutritional state, growth and maturation in Loligo forbesi. Moreno et al. examined differences in age, size-at-maturity and reproductive investment in different cohorts of Loligo vulgaris in relation to environmental influences. Consequences of such influences on cohort success have to be analysed taking into account the spatial organization of fished populations. Walters et al. (2004) encouraged this approach presenting “spatial life history trajectories” which involve nested designs or time-stepping structures

Water erosion in a Yellow-Red Ultisol under different patterns of simulated rain

Visou-se, neste trabalho, determinar as perdas de solo, água e nutrientes em um Argissolo Vermelho-Amarelo submetido a quatro diferentes padrões de chuva simulada. O estudo foi conduzido no Campo Experimental da Embrapa-Agrobiologia, localizado no município de Seropédica, RJ, e consistiu na aplicação de chuvas simuladas com diferentes padrões caracterizados como avançado (AV), intermediário (IN), atrasado (AT) e constante (CT), em uma área amostral de 0,80 m de largura por 1,0 m de comprimento. As chuvas tiveram duração de 60 min com uma lâmina total aplicada de 30 mm e um pico de 110 mm h-1, para os padrões de intensidade variável. Os resultados obtidos possibilitaram concluir que após 60 min de chuva simulada as perdas de solo e água observadas para o padrão atrasado foram, em média, superiores em 61,6, 46,4 e 13,6%, respectivamente, para o CT, AV e IN (solo), e de 42,0, 19,0 e 19,0%, respectivamente, para o AV, IN e CT (água) e as perdas de nutrientes não diferiram entre os padrões de precipitação, sendo mais influenciadas pelas perdas de água escoada superficialmente que pelo material sólido em suspensão.This study was carried out in order to determine the soil, water and nutrient losses in a Yellow-Red Ultisol, under four different patterns of simulated rainfall. The experiment was conducted at the Embrapa Agrobiologia experimental field, located in the municipality of Seropédica, Rio de Janeiro, Brazil. The study consisted in the application of simulated rains using variable rainfall intensity classified in different patterns as: advanced (AD), intermediate (IN), delayed (DE), and constant (CT), in plots 0.8 m wide and 1.0 m long. The rain had a duration of 60 min, with a total applied depth of 30 mm, and a peak of 110 mm h-1, for the variable intensity patterns. With the results obtained it was possible to verify that after 60 min of simulated DE pattern provided losses higher than CT, AD and IN, in 61.6, 46.4 and 13.6%, respectively (soil), and 42.0, 19.0 and 19.0% (run-off), respectively, for the AD, IN and CT patterns; and the nutrients losses did not differ among the rainfall patterns, being more affected by water run-off than solid material in suspension

GENETIC DIVERGENCE IN COMMON BEAN GENOTYPES CULTIVATED IN NORTH OF MINAS GERAIS, BRAZIL

INTRODUCTION: Common bean (Phaseolus vulgaris L.) presents a very great diversity of grains forms and color. It is a culture of great relevance for the Brazilian economic scenario, since its great importance and preference in the Brazilians food. The advance of genetic breeding has increased the number of cultivars with ideal characteristics of crop. However, the extensive use of one or more genetically similar cultivars provides narrowing of the genetic basis. Genetic diversity provides strategies that avoid the use of genetically similar cultivars and thereby avoid problems of origin mainly of biotic character. Thus, it is required that cultivars are not only adapted and productive, but also genetically divergent. Therefore, the objective of this work was to evaluate the genetic diversity of 25 common bean genotypes evaluated in the VCU tests in the north of Minas Gerais. MATERIAL AND METHODS: The test carried out in Janauba were composed of 25 common bean genotypes of the carioca commercial group, selected among the breeding programs of UFV, UFLA, EPAMIG and EMBRAPA Rice and Bean. Soil preparation was conventional one, with a plowing and two harrowing. The area was then grooved and fertilized using a mechanized seeder adjusted for 0.5 m spacing between rows with a planting density of about 15 plants m-1. The plots consisted of four rows of plants, 4 m in length, and additional irrigation was used. Grain yield, mean number of pods per plant (PPL), average number of grains per pod (GPP) and mass of 100 grains (M100) were evaluated. The data were submitted to analysis of variance for all the studied characteristics. The effect of the genotypes when significant were compared by the Scott- Knott test, at 5%. The generalized distance of Mahalanobis was used for the determinate genetic divergence among genotypes (SINGH, 1981). Tocher optimization method was used for the clustering. The analyzes were performed using the computational application in GENES genetic and statistical

Yield, water use efficiency, and yield response factor in carrot crop under different irrigation depths

The aim of the present study was to evaluate the effect of different irrigation depths on the yield, water use efficiency (WUE), and yield response factor (Ky) of carrot (cv. 'Brasília') in the edaphoclimatic conditions of Baixada Fluminense, RJ, Brazil. Field trials were conducted in a Red-Yellow Argisol in the 2010-2011period. A randomized block design was used, with 5 treatments (depths) and 4 replicates. Depths were applied by drippers with different flow rates, and the irrigation was managed by time domain reflectometry (TDR) technique. The reference (ETo) and crop (ETc) evapotranspiration depths reached 286.3 and 264.1mm in 2010, and 336.0 and 329.9mm in 2011, respectively. The root yield varied from 30.4 to 68.9t ha-1 as a response to treatments without irrigation and 100% replacement of the soil water depth, respectively. Values for WUE in the carrot crop varied from 15 to 31kg m-3 and the mean Ky value was 0.82. The mean values for Kc were obtained in the initial (0.76), intermediate (1.02), and final (0.96) stages. Carrot crop was influenced by different water depths (treatments) applied, and the highest value for WUE was obtained for 63.4% of soil water replacement.Publicada online Online em 5 de abril de 2016