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631.
Given recent evidence of a possible role of camelids in the epidemiology of diseases caused by mycoplasma species in other ruminants, we examined the prevalence of the mycoplasmas most commonly responsible for contagious agalactia (CA) in small ruminants among the dromedaries (Camelus dromedarius) of Lanzarote. On this island, one of the most arid regions of Spain in which CA is considered endemic, dromedaries and infected small ruminants such as goats and sheep, live in close contact. Specific IgG antibodies against Mycoplasma agalactiae and Mycoplasma mycoides subsp. mycoides (large colony biotype) were determined using two indirect enzyme immunoassays in 28% of the island's dromedary population. None of the serum samples tested were found to have antibodies against the two mycoplasma species, suggesting that the camels are not potential carriers of the main causative agents of CA.  相似文献   
632.
The main goal of this work is to describe the anthropogenic energy flux (Q F) in the city of S?o Paulo, Brazil. The hourly, monthly, and annual values of the anthropogenic energy flux are estimated using the inventory method, and the contributions of vehicular, stationary, and human metabolism sources from 2004 to 2007 are considered. The vehicular and stationary sources are evaluated using the primary consumption of energy based on fossil fuel, bio fuel, and electricity usage by the population. The diurnal evolution of the anthropogenic energy flux shows three relative maxima, with the largest maxima occurring early in the morning (??19.9 Wm?2) and in the late afternoon (??20.3 Wm?2). The relative maximum that occurs around noontime (??19.6 Wm?2) reflects the diurnal pattern of vehicle traffic that seems to be specific to S?o Paulo. With respect to diurnal evolution, the energy flux released by vehicular sources (Q FV) contributes approximately 50% of the total anthropogenic energy flux. Stationary sources (Q FS) and human metabolism (Q FM) represent about 41% and 9% of the anthropogenic energy flux, respectively. For 2007, the monthly values of Q FV, Q FS, Q FM, and Q F are, respectively, 16.8?±?0.25, 14.3?±?0.16, 3.5?±?0.03, and 34.6?±?0.41?MJ?m?2?month?1. The seasonal evolution monthly values of Q FV, Q FS, Q FM, and Q F show a relative minimum during the summer and winter vacations and a systematic and progressive increase associated with the seasonal evolution of the economic activity in S?o Paulo. The annual evolution of Q F indicates that the city of S?o Paulo released 355.2?MJ?m?2?year?1 in 2004 and 415.5?MJ?m?2?year?1 in 2007 in association with an annual rate of increase of 19.6?MJ?m?2?year?1 (from 2004 to 2006) and 30.5?MJ?m?2?year?1 (from 2006 to 2007). The anthropogenic energy flux corresponds to about 9% of the net radiation at the surface in the summer and 15% in the winter. The amplitude of seasonal variation of the maximum hourly value of the diurnal variation increases exponentially with latitude.  相似文献   
633.
Submarine groundwater discharge (SGD) is herein recognized as a significant pathway of material transport from land to the coastal SW Atlantic Ocean and thus, it can be a relevant factor affecting the marine biogeochemical cycles in the region. This paper focuses on the initial measurements of 226Ra, 228Ra and 222Rn made in Patagonia’s coastal zone of Chubut and Santa Cruz provinces (42°S–48°S, Argentina). 226Ra activity ranged from 2.9 to 73.5 dpm 100 L?1, and 228Ra activity ranged from 11.9 to 311.0 dpm 100 L?1 in groundwater wells. The radium activities found in Patagonia’s marine coastal regions and adjacent shelf indicate significant enrichment throughout the coastal waters. Groundwater samples presented the largest 222Rn activity and ranged from 2.66 to 1083 dpm L?1. Conversely, in the coastal marine environment, the 222Rn activity ranged from 1.03 to 6.23 dpm L?1. The Patagonian coastal aquifer showed a larger enrichment in 228Ra than in 226Ra, which is a typical feature for sites where SGD is dominant, probably playing a significant role in the biogeochemistry of these coastal waters.  相似文献   
634.
635.
This paper discusses the questions that emerged from the contact established by Europeans and Indians during the early modern era in what is today Brazil. It aims at demonstrating that dual structuralist models, which overemphasize material arguments of economic expansion and place conquerors and conquered in opposite ends, fail to grasp the rich cultural history embedded in the encounters that took place in that period. Colonization was a multifarious process that involved dealing with incompatible world views and often resulted in a complex history of temporary alliances, of conflict and strife, of negotiation and dialogue. The conquest and appropriation of the Brazilian territory, and the questions that they provoked, did not always put Europeans and Indians one against the other: not rarely, colonization demanded that the Europeans allied themselves to the natives against other Europeans, and that the natives allied themselves to Europeans against other natives. Even the control of the colony by the mother country should not be understood as a top-down movement, for metropolitan policies did not always have the expected answer from the colony or had differentiated social and spatial impacts there. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
636.
Landslides are natural geological disasters causing massive destructions and loss of lives, as well as severe damage to natural resources, so it is essential to delineate the area that probably will be affected by landslides. Landslide susceptibility mapping (LSM) is making increasing implications for GIS-based spatial analysis in combination with multi-criteria evaluation (MCE) methods. It is considered to be an effective tool to understand natural disasters related to mass movements and carry out an appropriate risk assessment. This study is based on an integrated approach of GIS and statistical modelling including fuzzy analytical hierarchy process (FAHP), weighted linear combination and MCE models. In the modelling process, eleven causative factors include slope aspect, slope, rainfall, geology, geomorphology, distance from lineament, distance from drainage networks, distance from the road, land use/land cover, soil erodibility and vegetation proportion were identified for landslide susceptibility mapping. These factors were identified based on the (1) literature review, (2) the expert knowledge, (3) field observation, (4) geophysical investigation, and (5) multivariate techniques. Initially, analytical hierarchy process linked with the fuzzy set theory is used in pairwise comparisons of LSM criteria for ranking purposes. Thereafter, fuzzy membership functions were carried out to determine the criteria weights used in the development of a landslide susceptibility map. These selected thematic maps were integrated using a weighted linear combination method to create the final landslide susceptibility map. Finally, a validation of the results was carried out using a sensitivity analysis based on receiver operator curves and an overlay method using the landslide inventory map. The study results show that the weighted overlay analysis method using the FAHP and eigenvector method is a reliable technique to map landslide susceptibility areas. The landslide susceptibility areas were classified into five categories, viz. very low susceptibility, low susceptibility, moderate susceptibility, high susceptibility, and very high susceptibility. The very high and high susceptibility zones account for 15.11% area coverage. The results are useful to get an impression of the sustainability of the watershed in terms of landsliding and therefore may help decision makers in future planning and mitigation of landslide impacts.  相似文献   
637.
A Gaussian correlation function characterizes smoothly heterogeneous media, while real heterogeneities in the Earth are often non-Gaussian in nature. Using the Born approximation, mean square amplitudes of the scattered waves have been derived for an elastic media characterized by the Von Karman correlation function. Heterogeneities with different power laws can be defined by the Von Karman correlation function. The sensitivity of fore- and backscattering to heterogeneities with different scales and properties (that is velocity and impedance) is discussed in this paper. The analytical expression for total scattered energy for the incident P waves is also derived for a random medium having the Von Karman correlation function. We find that at high frequencies, the scattered power of converted waves is a function of frequency. In the case of codawave excitation by local earthquakes, which must be handled by the full elastic-wave theory, we can define any type of inhomogeneity by the Von Karman correlation function. It also supports the idea that the lithosphere might have multiple-scale inhomogeneities.  相似文献   
638.
In the Soil Conservation Service Curve Number (SCS‐CN) method, the three levels of antecedent moisture condition (AMC) permit unreasonable sudden jumps in curve numbers, which result into corresponding jumps in the estimated runoff. A few recently developed SCS‐CN‐based models obviate this problem, yet they have several limitations. In this study, such a model incorporating a continuous function for antecedent moisture has been presented. It has several advantages over the other existing SCS‐CN‐based models. Its application to a large dataset from US watersheds showed to perform better than the existing SCS‐CN method and the others based on it. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
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