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221.
María NAJARRO Enrique PE?ALVER Ricardo PéREZ-DE LA FUENTE Jaime ORTEGA-BLANCO Cesar MENOR-SALVáN Eduardo BARRóN Carmen SORIANO Idoia ROSALES Rafael LóPEZ DEL VALLE Francisco VELASCO Fernando TORNOS Véronique DAVIERO-GOMEZ Bernard GOMEZ Xavier DELCLòS 《《地质学报》英文版》2010,84(4):959-976
<正>El Soplao outcrop,an Early Cretaceous amber deposit recently discovered in northern Spain (Cantabria),has been shown to be the largest site of amber with arthropod inclusions that has been found in Spain so far.Relevant data provided herein for biogeochemistry of the amber,palynology,taphonomy and arthropod bioinclusions complement those previously published.This set of data suggests at least two botanical sources for the amber of El Soplao deposit.The first(type A amber)strongly supports a source related to Cheirolepidiaceae,and the second(type B amber)shows non-specific conifer biomarkers.Comparison of molecular composition of type A amber with Frenelopsis leaves(Cheirolepidiaceae)strongly suggests a biochemical affinity and a common botanical origin.A preliminary palynological study indicates a regional high taxonomical diversity,mainly of pteridophyte spores and gymnosperm pollen grains.According to the preliminary palynological data,the region was inhabited by conifer forests adapted to a dry season under a subtropical climate.The abundant charcoalified wood associated with the amber in the same beds is evidence of paleofires that most likely promoted both the resin production and an intensive erosion of the litter,and subsequent great accumulation of amber plus plant cuticles.In addition,for the first time in the fossil record, charcoalified plant fibers as bioinclusions in amber are reported.Other relevant taphonomic data are the exceptional presence of serpulids and bryozoans on the surfaces of some amber pieces indicating both a long exposure on marine or brackish-water and a mixed assemblage of amber.Lastly,new findings of insect bioinclusions,some of them uncommon in the fossil record or showing remarkable adaptations,are reported.In conclusion,a documented scenario for the origin of the El Soplao amber outcrop is provided. 相似文献
222.
Biological communities in Mexico experienced profound changes in species composition and structure as a consequence of the environmental fluctuations during the Pleistocene. Based on the recent and fossil Mexican mammal checklists, we determine the distribution, composition, diversity, and community structure of late Pleistocene mammalian faunas, and analyze extinction patterns and response of individual species to environmental changes. We conclude that (1) differential extinctions occurred at family, genus, and species level, with a major impact on species heavier than 100 kg, including the extinction all proboscideans and several ruminants; (2) Pleistocene mammal communities in Mexico were more diverse than recent ones; and (3) the current assemblages of species are relatively young. Furthermore, Pleistocene relicts support the presence of biogeographic corridors; important refugia existed as well as centers of speciation in isolated regions. We identified seven corridors: eastern USA–Sierra Madre Oriental corridor, Rocky Mountains–Sierra Madre Occidental corridor, Central United States–Northern Mexico corridor, Transvolcanic Belt–Sierra Madre del Sur corridor, western USA–Baja California corridor, Tamaulipas–Central America gulf lowlands corridor, and Sonora–Central America Pacific lowlands corridor. Our study suggests that present mammalian assemblages are very different than the ones in the late Pleistocene. 相似文献
223.
Eduardo Gonzlez-Partida Antoni Camprubí Francisco Gonzlez-Snchez Jaime Snchez-Torres 《Journal of Geochemical Exploration》2006,89(1-3):143
The most important deposit in the Plomosas–Rosario district, Sinaloa, is the vein tract named Plomositas–Plomosas–Los Arcos. These are NNW–SSE striking veins hosted in rocks of the Lower Volcanic Supergroup (LVS), and also in rocks at the bottom of the Upper Volcanic Supergroup (UVS). Both supergroups belong to the Sierra Madre Occidental. These veins evolved from an early intermediate sulfidation stage (1), rich in base metal sulfides, to a low sulfidation stage (2), rich in silver sulfides and sulfosalts. There is also a 45 m-wide stockwork with native silver and gold. Stage 1 is found in the deeper portion of the veins whereas stage 2 is found in the most shallow portion of the deposit. These stages record fluid inclusion salinities ranging from 7 to 12 wt.% NaCl equiv., and from 0.2 to 3.5 wt.% NaCl equiv., respectively. Homogenization temperatures range from 120 °C for surface samples to 200 °C at a depth of 320 m. The low homogenization temperatures recorded, and the dispersion of veins within host rocks as veinlets, suggest that this deposit formed at shallow depths and was probably blind. 相似文献
224.
Luis Eduardo Antunes Vieira Walter D. Gonzalez Ezequiel Echer Bruce T. Tsurutani 《Solar physics》2004,223(1-2):245-258
In this paper we discuss the main-phase evolution of intense magnetic storms, associated with the passage of different interplanetary magnetic structures. It is shown that their evolution, driven by intense magnetic fields in the sheath region just behind interplanetary shocks, evolves faster (implying physically different magnetospheric configurations) than that associated with intense magnetic fields in the ejecta itself and in corotating streams. The estimated ring-current injection rate for the main phase of intense magnetic storms caused by sheath fields is ∼10 times greater than the estimated injection rate for N–S magnetic clouds. Based on these results, we propose storm-intensity criteria for several classes of the driving interplanetary structures. The time necessary to reach a Dst/SYM index threshold level is an important parameter for a space weather forecast. 相似文献
225.
Eduardo Krüger Patricia Drach Rohinton Emmanuel Oscar Corbella 《Theoretical and Applied Climatology》2013,112(1-2):127-141
From extensive outdoor comfort campaigns, preliminary outdoor comfort ranges have been defined for the local population of Glasgow, UK, in terms of two thermal indices: ‘Temperature Humidity Sun Wind’ (THSW) and ‘Physiological Equivalent Temperature’ (PET). A series of measurements and surveys was carried out from winter through summer 2011 during 19 monitoring campaigns. For data collection, a Davis Vantage Pro2 weather station was used, which was equipped with temperature and humidity sensors, cup anemometer with wind vane, silicon pyranometer and globe thermometer. From concurrent measurements using two weather stations, one located close to the city core and another located at a rural setting, approximately at a 15-km distance from the urban area of Glasgow, comparisons were made with regard to thermal comfort levels and to urban–rural temperature differences for different periods of the year. It was found that the two selected thermal indices (THSW and PET) closely correlate to the actual thermal sensation of respondents. Moreover, results show that the urban site will have fewer days of cold discomfort, more days of ‘neutral’ thermal sensation and slightly higher warm discomfort. The most frequent urban heat island intensity was found to be around 3° C, whereas the fraction of cooling to heating degree-hours for a T base of 65 °F was approximately 1/12th. 相似文献
226.
Shannon E. Brown Jon S. Warland Eduardo A. Santos Claudia Wagner-Riddle Ralf Staebler Meaghan Wilton 《Boundary-Layer Meteorology》2013,147(1):83-102
Analytical Lagrangian equations capable of predicting concentration profiles from known source distributions offer the opportunity to calculate source/sink distributions through inverted forms of these equations. Inverse analytical Lagrangian equations provide a practical means of estimating source profiles using concentration and turbulence measurements. Uncertainty concerning estimates of the essentially immeasurable Lagrangian length scale ( ${\mathcal{L}}$ ), a key input, impedes the operational practicality of this method. The present study evaluates ${\mathcal{L}}$ within a corn canopy by using field measurements to constrain an analytical Lagrangian equation. Measurements of net CO2 flux, soil-to-atmosphere CO2 flux, and in-canopy profiles of CO2 concentration provided the information required to solve for ${\mathcal{L}}$ in a global optimization algorithm for 30-min time intervals. For days when the canopy was a strong CO2 sink, the optimization frequently located ${\mathcal{L}}$ profiles that follow a convex shape. A constrained optimization then fit the profile shape to a smooth sigmoidal equation. Inputting the optimized ${\mathcal{L}}$ profiles in the forward and inverse Lagrangian equations leads to strong correlations between measured and calculated concentrations and fluxes. Coefficients of the sigmoidal equation were specific to each 30-min period and did not scale with any measured variable. Plausible looking ${\mathcal{L}}$ profiles were associated with negative bulk Richardson number values. Once the canopy senesced, a simple eddy diffusivity profile sufficed to relate concentrations and sources in the analytical Lagrangian equations. 相似文献
227.
228.
Julio Iglesias de Ussel Antonio Trinidad Diego RuIz Eduardo Battaner Antonio J. Delgado José M. Rodriguez-Espinosa Eduard Salvador-Solé José M. Torrelles 《Astrophysics and Space Science》1997,257(2):237-248
In this paper the main findings are presented of a recent study made by a team of sociologists from the University of Granada
on the professional astronomers currently working in Spain. Despite the peculiarities of this group – its youth, twentyfold
increase in size over the last 20 years, and extremely high rate of specialization abroad – in comparison with other Spanish
professionals, this is the first time that the sociological characteristics of the group have been studied discretely. The
most significant results of the study are presented in the following sections. Section 1 gives a brief historical background
of the development of Astronomy in Spain. Section 2 analyzes the socio-demographic profile of Spanish Astronomy professionals
(sex, age, marital status, etc.). Sections 3–5 are devoted to the college education and study programs followed by Spanish
astronomers, focusing on the features and evaluations of the training received, and pre- and postdoctoral study trips made
to research centers abroad. The results for the latter clearly show the importance that Spanish astronomers place on having
experience abroad. Special attention is paid to scientific papers published as a result of joint research projects carried
out with colleagues from centers abroad as a result of these study trips. Section 6 describes the situation of Astronomy professionals
within the Spanish job market, the different positions available and the time taken to find a job after graduation. Section
7 examines Astronomy as a discipline in Spain, including the astronomers' own opinions of the social status of the discipline
within Spanish society. Particular attention is paid to how Spanish astronomers view the status of Astronomy in Spain in comparison
with that of other European countries.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
229.
230.
Eduardo M. García-Roger M. del Mar Sánchez-Montoya Rosa Gómez M. Luisa Suárez M. Rosario Vidal-Abarca Jérôme Latron Maria Rieradevall Narcís Prat 《Aquatic Sciences - Research Across Boundaries》2011,73(4):567-579
In this study we examined the importance of seasonal changes in habitat features and aquatic macroinvertebrate responses in
temporary and perennial streams from two different catchments in the Western Mediterranean region in Spain. Macroinvertebrate
sampling was spatially intensive to account for the relative frequency of meso- (i.e., riffles and pools) and micro-habitats
(i.e., different mineral and organic-based substrata) at each site. Samples were collected at two distinctly different phases
of the hydrograph: (1) during the flowing period, when pool-riffle sequences were well-established, and (2) during the dry
phase, when only isolated pools were expected to occur in the temporary streams. During the dry season, both a reduction in
the available total habitat and in microhabitat diversity in all sites studied was observed. As a result, taxon richness decreased
in all streams, but more dramatically at temporary stream sites and particularly so in the infrequently remaining discontinuous
riffles. Macroinvertebrate assemblages differed among catchments (i.e., geographical identity) and sites (perennial vs. temporary).
Invertebrate differences were also strong within and among meso- and micro-habitats, particularly mineral and organic microhabitat
patches, and differences were due to both loss of taxa from some habitats and some taxa exhibiting certain habitat affinities. 相似文献