Communicating human health risks associated with disinfection by-products in drinking water supplies: a fuzzy-based approach   总被引：1，自引：2，他引：1  

Rehan Sadiq  Manuel J. Rodriguez  Syed A. Imran  Homayoun Najjaran 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(4):341-353

Chlorine used for the disinfection of water supplies can react with naturally occurring organic compounds and form potentially harmful disinfection by-products (DBPs). A risk index for two regulated groups of chlorinated DBPs—trihalomethanes (THMs) and haloacetic acids (HAAs), using fuzzy C-means (FCM) clustering algorithm and fuzzy rule-based modeling is proposed for risk communication. The proposed index evaluates the cancer and non-cancer risks individually for THMs and HAAs using the FCM algorithm. Subsequently, two different fuzzy rule-bases were used to evaluate the overall risk-index based on cancer and non-cancer risks. The overall risk-index will provide drinking water utilities with an effective communication tool for communicating aggregated water quality compliance. Simulated DBP occurrence data obtained from the City of Quebec, Canada, is used to demonstrate the application of this methodology.  相似文献   

深圳LAP-3000型风廓线雷达系统及应用   总被引：1，自引：0，他引：1  

陈元昭王小勇  王明洁胡娟 李辉 《广西气象》2007,28(3):73-76

介绍风廓线雷达的历史、LAP-3000型风廓线雷达的基本原理以及深圳市LAP-3000型风廓线雷达的数据存贮格式、风廓线雷达产品的显示等内容;并给出了几种典型风场在风廓线上的反映及对一次冷空气过程的分析。  相似文献   

Rainfall regionalization on the basis of the precipitation convective features using a raingauge network and weather radar observations     

Maria-Carmen Llasat  Manuel Ceperuelo  Tomeu Rigo 《Atmospheric Research》2007,83(2-4):415-426

The main objective of the present paper is to show a methodology for undertaking rainfall regionalization of a region taking into account the convective features of the precipitation, and useful for establishing homogeneous zones for improving the alert system. This methodology has been applied to a hydrographic region located in northeast Spain, with an area of 16000 km² and characterized by a highly contrasted topography. Information provided by meteorological radar and 5-min precipitation data for 126 automatic raingauges has been used for the period 1996–2002. The previous analysis done on the basis of the 1927–1981 rainfall rate series for the Jardí raingauge, located in Barcelona, has also been considered. To that end, the first step was to draw up a proposal for classification of the pluviometric episodes. Recourse was had for this purpose to definition of the β parameter, related with the greater or lesser convective character of the event and calculated on the basis of the rainfall intensity at the surface (Llasat, 2001) and, when data are available, on the basis of radar reflectivity. Results show that the threshold of 35 mm/h to characterize convective episodes from raingauge data can be corroborated from the radar point of view when convective precipitation is identified using 2-D algorithms with a reflectivity threshold of 43 dBZ. Once the soundness of the β parameter had been corroborated, it was applied to more than 2900 precipitation episodes recorded in the region, in order to discriminate the features of the different subregions and their time and space distribution throughout the entire series of the samples. Using this definition, 92% of the precipitation events recorded in this region, with accumulated rainfall above 35 mm, are classified as convective ones, representing 95% of the precipitation amount. Application of the β parameter combined with monthly rainfall data allows differentiation of 8 regions with different convective precipitation features.  相似文献   

A Mediterranean derecho: Catalonia (Spain), 17th August 2003     

J. Manuel Lpez 《Atmospheric Research》2007,83(2-4):272-283

At approximately 6:10 UTC in the morning of 17th August 2003, a squall line developed over south Catalonia (the northeast region of Spain). During the next 9 h, the squall moved rapidly northeast and crossed Catalonia and the French regions of Languedoc–Roussillon and Province, damaging and uprooting hundreds of trees and blocking trains in the region. Wind gusts reached were recoded up to 52 m/s with evidence of F2 intensity damage. This case study shows the characteristics of a derecho (widespread convectively induced windstorm).Radar observations of the evolving squall line show signatures often correlated with damaging surface winds, including:

a. Bow echoes,

b. Rear inflow notches,

c. Rear inflow jets,

d. Medium altitude radial convergence,

e. Narrow gradient of very marked reflectivity,

f. Development of isolated cells ahead of the convective line,

g. A band of convection off the northern end of the line known as a “warm advection wing”.

When examining the different surface observations, satellite, radar imagery and cloud-to-ground lightning data, this case shows many similarities to those investigated in the United States. The derecho is a hybrid case, but has many characteristics of warm season derechoes. This emanates from a mesoscale convective complex (MCC) moving along a quasi-stationary, low-level thermal boundary in an environment characterized by high potential instability and relatively strong mid-tropospheric winds.  相似文献   

Ages and metallicities of five intermediate-age star clusters projected towards the Small Magellanic Cloud     

Andrés E. Piatti  João F. C. SantosJr  Juan J. Clariá  Eduardo Bica  Ata Sarajedini  Doug Geisler 《Monthly notices of the Royal Astronomical Society》2001,325(2):792-802

Colour–magnitude diagrams are presented for the first time for L32, L38, K28 (L43), K44 (L68) and L116, which are clusters projected on to the outer parts of the Small Magellanic Cloud (SMC). The photometry was carried out in the Washington system C and T ₁ filters, allowing the determination of ages by means of the magnitude difference between the red giant clump and the main-sequence turn-off, and metallicities from the red giant branch locus. The clusters have ages in the range 2–6 Gyr , and metallicities in the range −1.65<[Fe/H]<−1.10, increasing the sample of intermediate-age clusters in the SMC. L116, the outermost cluster projected on to the SMC, is a foreground cluster, and somewhat closer to us than the Large Magellanic Cloud. Our results, combined with those for other clusters in the literature, show epochs of sudden chemical enrichment in the age–metallicity plane, which favour a bursting star formation history as opposed to a continuous one for the SMC.  相似文献   

Metal speciation and environmental impact on sandy beaches due to El Salvador copper mine, Chile   总被引：1，自引：0，他引：1  

Ramirez M  Massolo S  Frache R  Correa JA 《Marine pollution bulletin》2005,50(1):62-72

Several coastal rocky shores in northern Chile have been affected by the discharges of copper mine tailings. The present study aims to analyze the chemical speciation of heavy metals in relation to the diversity of sessile species in the rocky intertidal benthic community on the northern Chilean coast, which is influenced by the presence of copper mine tailings. In particular, the chemical forms of Cd, Cu, Fe, Mn, Ni, Pb and Zn in beach sediment samples collected in the area influenced by El Salvador mine tailings were studied using a sequential chemical extraction method. In general, all the elements present a maximum concentration in the area near the actual discharge point (Caleta Palito). With regard to Cu and Mn, the concentrations range between 7.2-985 and 746-22,739 microg/g respectively, being lower than background levels only in the control site of Caleta Zenteno. Moreover, the correlation coefficients highlight that Fe, Mn and Ni correlate significantly and positively in the studied area, showing a possible common, natural origin, whilst Cu shows a negative correlation with Fe, Mn and Ni. It could be possible that Cu has an anthropogenic origin, coming from mining activity in the area. Cd, Fe, Mn, Ni, Pb and Zn are mostly associated with the residual phase, whilst Cu presents a different speciation pattern, as resulted from selective extractions. In fact, Cu is highly associated with organic and exchangeable phases in contaminated localities, whilst it is mainly bound to the residual phase in control sites. Moreover, our results, compared to local biological diversity, showed that those sites characterized by the highest metal concentrations in bioavailable phase had the lowest biodiversity.  相似文献   

Further details on the applicability of Thellier paleointensity method: The effect of magnitude of laboratory field     

Juan Morales  Avto Goguitchaichvili  Luis M. Alva-Valdivia  Jaime Urrutia-Fucugauchi 《Comptes Rendus Geoscience》2006,338(8):507-513

Twenty years after Tanaka and Kono's pioneering contribution (Tanaka and Kono, 1984), we give some new details on the effect of applied field strength during Thellier paleointensity experiments. Special attention is paid to the relation of magnitude of laboratory field and Coe's quality factors (Coe et al., 1978). Full thermoremanent magnetizations were imparted on natural samples containing low-Ti titanomagnetites of pseudo-single domain structure in a 40-μT magnetic field from 600?°C to room temperature. The samples were subjected to the routine Thellier procedure using a wide range of applied laboratory fields. Results indicate that values of laboratory fields may be accurately reproduced within 2% of standard error. The quality factors, however, decrease when the magnitude of ‘ancient’ field does not match to applied laboratory fields. To cite this article: J. Morales et al., C. R. Geoscience 338 (2006).  相似文献   

The connection between globular cluster systems and the host galaxies     

Duncan A. Forbes  Juan C. Forte 《Monthly notices of the Royal Astronomical Society》2001,322(2):257-261

A large number of early-type galaxies are now known to possess blue and red subpopulations of globular clusters. We have compiled a data base of 28 such galaxies exhibiting bimodal globular cluster colour distributions. After converting to a common V – I colour system, we investigate correlations between the mean colour of the blue and red subpopulations with galaxy velocity dispersion. We support previous claims that the mean colours of the blue globular clusters are unrelated to their host galaxy. They must have formed rather independently of the galaxy potential they now inhabit. The mean blue colour is similar to that for halo globular clusters in our Galaxy and M31. The red globular clusters, on the other hand, reveal a strong correlation with galaxy velocity dispersion. Furthermore, in well-studied galaxies the red subpopulation has similar, and possibly identical, colours to the galaxy halo stars. Our results indicate an intimate link between the red globular clusters and the host galaxy; they share a common formation history. A natural explanation for these trends would be the formation of the red globular clusters during galaxy collapse.  相似文献   

Aftershock tectonics of the 1978 Tabas-e-Golshan (Iran) earthquake sequence: a documented active 'thin-and thick-skinned tectonic' case     

Manuel Berberian 《Geophysical Journal International》1982,68(2):499-530

Summary. In this study a locally recorded aftershock sequence of the 1978 Tabas-e-Golshan earthquake ( M_s = 7.4) was accurately located. Out of 1560 located events, 329 best-located aftershocks passed a strict quality criterion. These well-located aftershocks, which have uncertainties in epicentre and in focal depth of about 1 and 2 km respectively, together with the well-constrained focal mechanisms, provided a detailed picture of active continental deformation during an aftershock sequence.
Almost all aftershocks follow very closely the pattern of the earthquake faults at the surface and lie in the hanging-wall block of the active fault. The hypocentres occurred mainly at depths less than 23 km with a high concentration of seismic activity between 8–14 km depth. The aftershocks clearly demonstrate an active imbricate listric thrust system with fault planes flattening into a basement decollement zone, and the reactivation of different basement reverse faults in response to a considerable amount of shortening of the top sedimentary cover. The sense of motion was almost universally thrusting and the aftershocks shared the same tectonic causes as the main shock.
The study indicates that the development of the young fold-thrust mountain belts necessarily involves basement shortening (thin-and thick-skinned tectonics) and that the 'frontal reverse faults' in young active fold-thrust mountain belts are the most seismically active faults. Geological and seismic data propose that the active frontal reverse fault systems are possibly reactivated old normal faults and may add support to the contention of reversal of fault motion during re thickening of continental crust. The active 'thin-and thick-skinned tectonics' documented in this study may prevail in other young and active fold-thrust mountain belts which are characterized by a thick sequence of telescoped top sedimentary cover over a decollement detachment zone.  相似文献   

Palaeomagnetism of a sequence of Upper Palaeozoic-Lower Mesozoic red beds from Argentina     

Ana M. Sinito  Daniel A. Valencio  Juan F. Vilas 《Geophysical Journal International》1979,58(2):237-247

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