Was there a ‘medieval warm period’, and if so,where and when?     

Malcolm K. Hughes  Henry F. Diaz 《Climatic change》1994,26(2-3):109-142

It has frequently been suggested that the period encompassing the ninth to the fourteenth centuries A.D. experienced a climate warmer than that prevailing around the turn of the twentieth century. This epoch has become known as theMedieval Warm Period, since it coincides with the Middle Ages in Europe. In this review a number of lines of evidence are considered, (including climatesensitive tree rings, documentary sources, and montane glaciers) in order to evaluate whether it is reasonable to conclude that climate in medieval times was, indeed, warmer than the climate of more recent times. Our review indicates that for some areas of the globe (for example, Scandinavia, China, the Sierra Nevada in California, the Canadian Rockies and Tasmania), temperatures, particularly in summer, appear to have been higher during some parts of this period than those that were to prevail until the most recent decades of the twentieth century. These warmer regional episodes were not strongly synchronous. Evidence from other regions (for example, the Southeast United States, southern Europe along the Mediterranean, and parts of South America) indicates that the climate during that time was little different to that of later times, or that warming, if it occurred, was recorded at a later time than has been assumed. Taken together, the available evidence does not support aglobal Medieval Warm Period, although more support for such a phenomenon could be drawn from high-elevation records than from low-elevation records.The available data exhibit significant decadal to century scale variability throughout the last millennium. A comparison of 30-year averages for various climate indices places recent decades in a longer term perspective.  相似文献   

Regional modeling of climate change impacts on smallholder agriculture and ecosystems in Central America     

Lee Hannah  Camila I. Donatti  Celia A. Harvey  Eric Alfaro  Daniel Andres Rodriguez  Claudia Bouroncle  Edwin Castellanos  Freddy Diaz  Emily Fung  Hugo G. Hidalgo  Pablo Imbach  Peter Läderach  Jason P. Landrum  Ana Lucía Solano 《Climatic change》2017,141(1):29-45

Climate change will have serious repercussions for agriculture, ecosystems, and farmer livelihoods in Central America. Smallholder farmers are particularly vulnerable due to their reliance on agriculture and ecosystem services for their livelihoods. There is an urgent need to develop national and local adaptation responses to reduce these impacts, yet evidence from historical climate change is fragmentary. Modeling efforts help bridge this gap. Here, we review the past decade of research on agricultural and ecological climate change impact models for Central America. The results of this review provide insights into the expected impacts of climate change and suggest policy actions that can help minimize these impacts. Modeling indicates future climate-driven changes, often declines, in suitability for Central American crops. Declines in suitability for coffee, a central crop in the regional economy, are noteworthy. Ecosystem models suggest that climate-driven changes are likely at low- and high-elevation montane forest transitions. Modeling of vulnerability suggests that smallholders in many parts of the region have one or more vulnerability factors that put them at risk. Initial adaptation policies can be guided by these existing modeling results. At the same time, improved modeling is being developed that will allow policy action specifically targeted to vulnerable groups, crops, and locations. We suggest that more robust modeling of ecological responses to climate change, improved representation of the region in climate models, and simulation of climate influences on crop yields and diseases (especially coffee leaf rust) are key priorities for future research.  相似文献   

Trophic ecology of the Patagonian skate, Bathyraja macloviana, on the Argentine continental shelf     

Scenna  L.B.; Garcia de la Rosa  S.B.; Diaz de Astarloa  J.M. 《ICES Journal of Marine Science》2006,63(5):867-874

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Reproductive biology and abundance of the white-dotted skate, Bathyraja albomaculata, in the Southwest Atlantic     

Ruocco  Natalia L.; Lucifora  Luis O.; Diaz de Astarloa  Juan M.; Wohler  Otto 《ICES Journal of Marine Science》2006,63(1):105-116

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Comparison of acoustic backscatter measurements from a ship-mounted Acoustic Doppler Current Profiler and an EK500 scientific echo-sounder     

Griffiths  Gwyn; Diaz  Jose I. 《ICES Journal of Marine Science》1996,53(2):487-491

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Trophic ecology of the Patagonian skate, Bathyraja macloviana, on the Argentine continental shelf     

Scenna  L.B.; Garcia de la Rosa  S.B.; Diaz de Astarloa  J.M. 《ICES Journal of Marine Science》2006,63(9):1765

When this article was originally published  相似文献   

Perspectives for Distributed Observations of Near-Earth Space Using a Russian–Cuban Observatory     

D. V. Bisikalo  I. S. Savanov  S. A. Naroenkov  M. A. Nalivkin  A. S. Shugarov  N. S. Bakhtigaraev  P. A. Levkina  M. A. Ibragimov  E. Yu. Kil’pio  M. E. Sachkov  A. P. Kartashova  A. M. Fateeva  Marta R. Rodriguez Uratsuka  Ramses Zaldivar Estrada  Antonio Alonsa Diaz  Omar Pons Rodríguez  Fidel Hernandes Figuera  Maritza Garcia Garcia 《Astronomy Reports》2018,62(6):367-377

The creation of a specialized network of large, wide-angle telescopes for distributed observations of near-Earth space using a Russian–Cuban Observatory is considered. An extremely important goal of routine monitoring of near-Earth and near-Sun space is warding off threats with both natural and technogenic origins. Natural threats are associated with asteroids or comets, and technogenic threats with man-made debris in near-Earth space. A modern network of ground-based optical instruments designed to ward off such threats must: (a) have a global and, if possible, uniform geographic distribution, (b) be suitable for wide-angle, high-accuracy precision survey observations, and (c) be created and operated within a single network-oriented framework. Experience at the Institute of Astronomy on the development of one-meter-class wide-angle telescopes and elements of a super-wide-angle telescope cluster is applied to determine preferences for the composition of each node of such a network. The efficiency of distributed observations in attaining maximally accurate predictions of the motions of potentially dangerous celestial bodies as they approach the Earth and in observations of space debris and man-made satellites is estimated. The first estimates of astroclimatic conditions at the proposed site of the future Russian–Cuban Observatory in the mountains of the Sierra del Rosario Biosphere Reserve are obtained. Special attention is given to the possible use of the network to carry out a wide range of astrophysical studies, including optical support for the localization of gravitational waves and other transient events.  相似文献   

Post-processing of sequential indicator simulation realizations for modeling geologic bodies     

Jorge Kazuo Yamamoto  Paulo Milton Barbosa Landim  Antonio Tadashi Kikuda  Claudio Benedito Baptista Leite  Santiago Diaz Lopez 《Computational Geosciences》2015,19(1):257-266

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Accelerating the solution of linear systems appearing in two-phase reservoir simulation by the use of POD-based deflation methods     

Diaz Cortés  Gabriela Berenice  Vuik  Cornelis  Jansen  Jan-Dirk 《Computational Geosciences》2021,25(5):1621-1645

We explore and develop a Proper Orthogonal Decomposition (POD)-based deflation method for the solution of ill-conditioned linear systems, appearing in simulations of two-phase flow through highly heterogeneous porous media. We accelerate the convergence of a Preconditioned Conjugate Gradient (PCG) method achieving speed-ups of factors up to five. The up-front extra computational cost of the proposed method depends on the number of deflation vectors. The POD-based deflation method is tested for a particular problem and linear solver; nevertheless, it can be applied to various transient problems, and combined with multiple solvers, e.g., Krylov subspace and multigrid methods.

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Contaminant concentrations, biochemical and hematological biomarkers in blood of West Indian manatees Trichechus manatus from Brazil     

Anzolin DG  Sarkis JE  Diaz E  Soares DG  Serrano IL  Borges JC  Souto AS  Taniguchi S  Montone RC  Bainy AC  Carvalho PS 《Marine pollution bulletin》2012,64(7):1402-1408

The West Indian manatee Trichechus manatus is threatened with extinction in Brazil, and this study focused on nondestructive blood samples analyzed for metals, polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), as well as biochemical and hematological biomarkers. Studied manatees were kept at Projeto Peixe-Boi headquarters in Pernambuco State, and at two natural areas in estuaries where they are released to the wild. Manatees kept at the natural estuary in Paraiba State have blood concentrations of Al, Pb, Cd, Sn that are 11, 7, 8 and 23 times greater, respectively, than the concentrations found in blood of animals from the same species in Florida, USA. An inhibition of butyrylcholinesterase in manatees kept at the two reintroduction sites in Alagoas and Paraiba States indicated possible exposure of the animals to cholinesterase inhibitor insecticides. PCBs and OCPs were not detected. Results from this study will help delineate conservation efforts in the region.  相似文献