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621.
622.
Ana I. Dittel C.E. Epifanio Juan Bautista Chavarria 《Estuarine, Coastal and Shelf Science》1985,20(5):593-602
Tropical blue crabs Callinectes arcuatus were collected by trawling in the Gulf of Nicoya on the Pacific coast of Costa Rica, Central America. The gulf population was generally dominated by females. Adult females were common in the upper, more estuarine regions of the gulf during rainy season, but appeared to migrate to the lower gulf during dry season for spawning. Biomass varied with seasonal changes in abundance, but was generally similar to biomass of C. sapidus in Chesapeake Bay. Analysis of size frequency indicated that the population is numerically dominated by adults during January and February and that juveniles are common during the remainder of the year. Extrapolation of available data suggests that female crabs reach maturity in approximately one year after hatching. 相似文献
623.
624.
Ana B. González Pablo Martín David J. López 《Celestial Mechanics and Dynamical Astronomy》1999,75(1):29-38
Recently, González, Martín and Farto have developed new numerical methods (RKGM methods) of Runge–Kutta type and fixed step
size for the numerical integration of perturbed oscillators. Moreover, it seems natural to study the behaviour of these new
methods for the accurate integration of orbital problems after the application of linearizing transformation, such us KS or
BF due to the fact that in these variables, the structure of the problem is of the form of perturbed oscillators, for which
the methods constructed are indicated. In this paper, we check the efficiency of these new methods when integrating the satellite
problem. The RKGM methods show a very good behaviour when they compete with other, classical and special, methods.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
625.
Eduardo García-Portugués Ana M. G. Barros Rosa M. Crujeiras Wenceslao González-Manteiga José Pereira 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(5):1261-1275
A nonparametric test for assessing the independence between a directional random variable (circular or spherical, as particular cases) and a linear one is proposed in this paper. The statistic is based on the squared distance between nonparametric kernel density estimates and its calibration is done by a permutation approach. The size and power characteristics of various variants of the test are investigated and compared with those for classical correlation-based tests of independence in an extensive simulation study. Finally, the best-performing variant of the new test is applied in the analysis of the relation between the orientation and size of Portuguese wildfires. 相似文献
626.
Gabriel Granco Marcellus Marques Caldas Jason Scott Bergtold Ana Claudia Sant’Anna 《GeoJournal》2017,82(1):63-80
Within the past decade, the sugarcane ethanol industry in Brazil has increased its production capacity to meet rising domestic demand for ethanol. However, to achieve this growth the industry has had to expand into new frontiers in the Brazilian Cerrado, specifically in the states of Goiás and Mato Grosso do Sul, which is now the second largest producing area of ethanol in Brazil. We argue that the expansion into the Brazilian Cerrado is a result of the interactions between the increase in demand, governmental policies, infrastructure, and factors that have prevented traditional sugarcane producing regions from meeting the increasing demand for ethanol. This paper analyzes the policies that have shaped the sugarcane industry in Brazil and the expansion of the industry across the country. The policies and issues examined include those that led to the concentration and consolidation of the sugarcane industry in the state of São Paulo and the consequences of this consolidation; the influence of governmental policies on the decision-making process of producers and industry; the state-level policies designed to expand the industry into Goiás and Mato Grosso do Sul states; infrastructure development; and the Sugarcane Agroecological Zoning policies. Through this study we conclude that the ethanol industry identified the Cerrado states as an opportunity for investment, given the good agricultural conditions for producing sugarcane, affordable land prices and favorable state-level fiscal incentive policies. In addition, there is a need for further regional development policies as the interaction between the sugarcane sector and regional government is likely to continue into the future. 相似文献
627.
Ana Maria Rodrigues Adília PiresSónia Mendo Victor Quintino 《Estuarine, Coastal and Shelf Science》2009
This paper reports the presence of Diopatra marocensis in European waters, for which Diopatra neapolitana was the only species recognized until recently. Both species coexist in transitional waters, where D. marocensis may be mistaken for young specimens of D. neapolitana. The population of D. marocensis studied in the coastal shelf can be traced back to 1997 and is increasing in density, apparently benefiting from a local anthropogenic organic enrichment source. 相似文献
628.
Ana Da Silva Vincenzo Costanzo-Álvarez Nuri Hurtado Milagrosa Aldana Germán Bayona Oswaldo Guzmán Diego López-Rodríguez 《Studia Geophysica et Geodaetica》2010,54(4):607-631
In this work we have assessed the hybrid algorithm of NeuroFuzzy logic (NFL), to establish a correlation between global climatic
changes (benthic foraminiferal δ18O data), experimental S-ratio (factor characterizing stability of remanent magnetization) and magnetic susceptibility (κ).
Magnetic proxies have been measured in 44 samples of the Colombian stratigraphic well Saltarín 1A (distal Llanos foreland
basin). κ and Sratios were linked to global δ18O data assuming a constant accumulation rate for a 305 meters thick stratigraphic interval flanked by the two palynological
age constrains available. This interval encompasses, from top to base, the bottom of the Guayabo formation, the León, and
the upper unit of the Carbonera formations (lower to middle Miocene). The best inference is accomplished applying a Takagi-Sugeno-Kan
(TSK) fuzzy model with four fuzzy rules and the δ18O, S-ratios and κ data used in a linear form to train the system. These results are interpreted as the outcome of a significant
influence of global climatic changes upon magnetic proxies. A stronger correlation is perhaps prevented by the likely influence
of local and regional tectonic events and climatic changes that could have affected the distal segment of the Colombian Llanos
foreland basin during Miocene times. We argue that late diagenesis of primary magnetic minerals and the assumption of a constant
accumulation rate might have a minor influence on these results. 相似文献
629.
Climate change is a global phenomenon, and its outcomes affect societies around the world. So far, however, studies on media representations of climate change have mostly concentrated on Western societies. This paper goes beyond this limited geographical scope by presenting a comparative analysis of issue attention in 27 countries. The sample includes, among others, countries that have committed themselves to greenhouse gas emission reductions under the Kyoto Protocol such as Germany as well as countries that are strongly affected by the consequences of climate change like India. In a first step, it describes the development of media attention for climate change in these countries from 1996 to 2010. Second, it compares the amount of media attention and explores whether it corresponds with indicators measuring the relevance of climate change and climate policies for a country. The analyses show that climate change coverage has increased in all countries. Still, overall media attention levels, as well as the extent of growth over time, differ strongly between countries. Media attention is especially high in carbon dependent countries with commitments under the Kyoto Protocol. 相似文献
630.