An integral equation approach for 2.5-dimensional forward and inverse electromagnetic scattering     

Aria Abubakar  Peter M van den Berg  Tarek M Habashy 《Geophysical Journal International》2006,165(3):744-762

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Gender and voluntary work in late adulthood in rural communities in the Netherlands     

Joos Droogleever Fortuijn  Marieke van der Meer 《GeoJournal》2006,65(4):381-392

This article discusses the involvement of older women and men in voluntary work in rural communities in the Netherlands. Gender, ageing and civil society form the core concepts in the article. Politicians and policy makers in the Netherlands are worried about the perceived decline of civil society and about the consequences of this decline for specific categories of older women in terms of well-being and social exclusion. The paper presents the results of two surveys of involvement of older women and men in civic organisations, voluntary work and local actions. The surveys indicate high levels of involvement of both women and men. No gender differences are found in activity level. However, the data demonstrate the gendered nature of civil society. Women are more engaged in informal voluntary work and informal local actions, while men are more active in formal organisations and functions. This gender segmentation is not absolute, however. Many older women and men transgress the traditional feminine–masculine boundaries. The surveys highlight the involvement of women and men in rural communities, but indicate lower activity levels in urban areas.  相似文献   

The effect of thermal treatment on the 57Fe Mössbauer spectrum of beryl     

Geraldo Magela da Costa  Gabriel de Oliveira Polli  Márcio A. Kahwage  Eddy de Grave  Antônio Claret Soares Sabioni  Júlio Cesar Mendes 《Physics and Chemistry of Minerals》2006,33(3):161-166

Mössbauer spectra (MS) of blue, green and yellow beryl (ideally Be₃Al₂Si₆O₁₈) containing approximately 1% of iron were obtained at 295 and 500 K. Room temperature (RT) spectra of both blue and green samples showed the presence of an asymmetric Fe²⁺ doublet (ΔE _Q~2.7 mm/s, δ~1.1 mm/s), with a very broad low-velocity peak. There is no clear evidence for the presence of a ferric component. The MS of the yellow sample at RT consists of an intense central absorption with parameters typical for Fe³⁺ (ΔE _Q~0.4 mm/s, δ~0.29 mm/s), plus an apparently symmetrical Fe²⁺ doublet. This sample acquires a light-blue shade upon heating in air at about 620 K. Thermal treatments at high temperatures caused no significant changes in the MS, but the green and yellow beryl acquire a blue colour. All these results are interpreted in relation to the existence of channel water and the distribution of iron among the available crystallographic sites.  相似文献   

Reviews on books, internet and scientific media     

J. Rasanen  Fakhry A. Assaad  A. M. de Grosbois 《Environmental Geology》2006,51(4):655-657

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Book Reviews     

Jörg Matschullat  Anne Marie de Grosbois  Fakhry A Assaad 《Environmental Geology》2006,49(8):1224-1225

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Spatial assessment and redesign of a groundwater quality monitoring network using entropy theory, Gaza Strip, Palestine   总被引：3，自引：0，他引：3  

Y. Mogheir  V. P. Singh  J. L. M. P. de Lima 《Hydrogeology Journal》2006,14(5):700-712

Using entropy theory, a methodology was developed for the evaluation and redesign of groundwater quality monitoring wells in the Gaza Strip in Palestine. Essential to the methodology is the development of a Transinformation Model (TM) which yields the amount of information transfer and the dependency between the wells as a function of distance. The TM parameters, such as the minimum transinformation and the range, were employed for evaluating the network which revealed that most of the distances between wells were less than the range. It also indicated that a high percentage of redundant information existed in the network. Therefore, the network was reduced by superimposing a square pattern over the monitored area and selecting one well per square block in a stratified pattern. The methodology was tested using the chloride data collected from 1972–2000 from 417 groundwater quality monitoring wells in the Gaza Strip. The number of the groundwater quality monitoring wells in the Gaza Strip was reduced by 53%, while there was 26% redundant information based on the minimum existing distance between wells. This methodology is meant to help monitor the groundwater quality (salinity) in the Gaza Strip.  相似文献   

Vertical velocities of European coastal sites derived from continuous GPS observations     

Klaus Kaniuth  Sandra Vetter 《GPS Solutions》2005,9(1):32-40

Vertical velocities of 30 European permanent Global Positioning System (GPS) stations at or close to tide gauge sites are estimated from more than 3 years of continuous observations. The results of two different solution strategies are presented and compared. The first approach accumulates the daily free network normal equations, the second introduces all sets of daily ellipsoidal height estimates and their covariance matrix into a subsequent common least squares adjustment. In both solutions, mean station heights at a reference epoch, linear vertical velocities, height discontinuities and short period height offsets are estimated. The second approach solves in addition for periodic annual signals and for site-specific pressure loading coefficients. The vertical velocities range from +8 mm/year in the center of the Fennoscandian uplift area to –4 mm/year at a few subsiding locations. Apart from these extrema, most of the sites experience only very small vertical motions. The standard deviations from the second approach providing more realistic error estimates are well below 0.15 mm/year. Some specific data problems are discussed.  相似文献   

DMS and SO2 at Baring Head, New Zealand: Implications for the Yield of SO2 from DMS     

Warren J. de Bruyn  Mike Harvey  Jill M. Cainey  Eric S. Saltzman 《Journal of Atmospheric Chemistry》2002,41(2):189-209

Atmospheric dimethyl sulfide (DMS) and sulfur dioxide (SO₂) concentrations were measured at Baring Head, New Zealandduring February and March 2000. Anti-correlated DMS and SO₂ diurnalcycles, consistent with the photochemical production of SO₂ from DMS, were observed in clean southerly air off the ocean. The data is used to infer a yield of SO₂ from DMS oxidation. The estimated yields are highly dependent on assumptions about the DMS oxidation rate. Fitting the measured data in a photochemical box model using model-generated OH levels and the Hynes et al. (1986) DMS + OH rate constant suggests that theSO₂ yield is 50–100%, similar to current estimates for the tropical Pacific.However, the observed amplitude of the DMS diurnal cycle suggests that the oxidation rate is higher than that used by the model, and therefore, that theSO₂ yield is lower in the range of 20–40%.  相似文献   

Are Natural Climate Forcings Able to Counteract the Projected Anthropogenic Global Warming?     

Cédric Bertrand  Jean-Pascal van Ypersele  André Berger 《Climatic change》2002,55(4):413-427

A two-dimensional global climate model is used to assessthe climatic changes associated with the new IPCC SRES emissions scenarios and to determine which kind of changes in total solar irradiance and volcanic perturbations could mask the projected anthropogenic global warming associated to the SRES scenarios. Our results suggest that only extremely unlikely changes in total solar irradiance and/or volcanic eruptions would be able to overcome the simulated anthropogenic global warming over the century. Nevertheless, in the critical interval of the next two decades the externally-driven natural climate variability might possibly confuse the debate about temperature trends and impede detection of the anthropogenic climate change signal.  相似文献   

贵州关岭生物群中植物化石的发现及其意义   总被引：4，自引：1，他引：4  

孟繁松  汪啸风  陈孝红  陈辉明  张振来  徐光洪  陈立德  王传尚  孙亚莉 《地层学杂志》2002,26(3):170-172,T001,T002

关岭生物群是近年来在我国贵州关岭地区瓦窑组中发现的一个十分重要的生物群 ,其中的植物化石经研究计有 Equisetites cf.arenaceus(Jaeger) Bronn.、Ctenozamitessarrani Zeiller。依据植物化石 C.sarrani常见于晚三叠世和 E.cf.arenaceus系似木贼属中较古老的类型 ,指出含植物化石的地层时代为晚三叠世卡尼期。瓦窑组系海相沉积 ,其中的植物化石无疑为异地埋藏 ,但从化石通常保存尚好来看 ,估计搬运的距离不会很远 ,它们可能是从距海岸不远的陆地被河流带到较平静的海湾或海槽而沉积下来的。此外 ,从该组植物茎干化石具清楚的年轮分析 ,推测卡尼期时 ,贵州关岭一带为非热带雨林地区 ,一年中气候不是四季如一 ,而是有明显的季节变化  相似文献