How complementary are epibenthic assemblages in artificial and nearby natural rocky reefs?

The present study analyses the composition, structure and trophic function of epibenthic assemblages in two artificial reefs (ARs) 16 years after deployment and in nearby natural reefs (NRs), aiming at providing insights on the complementarity between both habitats. Current findings suggest that after 16 years the ARs (concrete blocks), located in southern Portugal, do not act as surrogates for NRs, as epibenthic assemblages differed between reef types in composition, structure and trophic function. NRs showed higher diversity and complementarity (i.e. beta-diversity) than ARs, evidencing higher redundancy. Higher heterogeneity within NRs was also evidenced by the multi-dimensional scaling analysis based on abundance, biomass and trophic composition. NRs presented higher abundance of molluscs and biomass of sponges, resulting in differences in the trophic function: suspension-feeding dominated the NRs, while within ARs there was an ascendency of carnivory. Although not acting as surrogates for NRs and provided that no adverse effects (e.g. establishment of non-native species) were detected, ARs may have a significant contribution for the increase of regional diversity, as evidenced by the highest complementarity levels observed between assemblages in both reefs.     

The diversity and abundance of polychaetes (Annelida) are altered in sediments impacted by alumina refinery discharge in the Northern Territory,Australia

We collected polychaete diversity and abundance data at a range of impacted and reference sites near an alumina refinery in Melville Bay, northern Australia. The aims were to measure the impact of sediment modified by the alumina refinery discharge on polychaete communities and secondly to gather baseline data from which to measure future changes. Polychaete communities in both soft-bottom habitats and subtidal areas adjacent to mangrove forests were studied. We also developed and deployed an artificial substratum device to sample polychaetes associated with hard-substrate habitats. For each habitat, polychaete community composition was different between impacted and reference sites and at multiple time points. The impact of future changes either from bioremediation or management practices can be measured against these baseline data. Indicator species analysis was used to identify polychaete species that were significantly different at the locations tested, and we discuss their potential as indicator species.     

爆破振动测试在矿区的应用

道路铺设、矿山开采、隧道开挖、地震勘探等工程施工免不了要进行炸药爆破,炸药爆破所产生的剧烈振动必然会对周围的环境造成破坏,从而引起不必要的经济损失和纠纷,为了解决矛盾,对振动引起的损失和涉及的范围有个科学的评判,爆破时采用精密的地震勘探仪器进行不同炮距的振动测试,以做出公证的裁决。本文以两个实例来说明地震勘查在振动测试领域的有效应用。     

北京地区地下水人工回灌简介

北京地区开展人工回灌有了近50年的历史,经历了试验和工程实施阶段。试验阶段包括深井、砂石坑、大口井回灌等试验,工程实施包括城市雨洪利用和再生水回灌利用等。     

Optimization and Modeling of the Photocatalytic Degradation of the Insect Repellent DEET in Aqueous TiO2 Suspensions

Response surface methodology (RSM) and artificial neural networks (ANNs) based on a multivariate central composite design (CCD) were applied to model and optimize the photocatalytic degradation of N,N‐diethyl‐m‐toluamide (DEET). The individual and interaction effects of three main operating factors (mass of TiO₂, initial DEET concentration, and irradiation intensity) on process efficiency were estimated, proving their important effect on % DEET removal. Among the independent variables, TiO₂ concentration displayed the highest effect on DEET degradation followed by initial DEET concentration and UV intensity. The optimization and prediction capabilities of ANNs and RSM were compared on the basis of root mean squared error, mean absolute error, absolute average deviation, and correlation coefficient values. Results proved the usefulness and capability of the experimental design strategy for successful investigation and modeling of the photocatalytic process. Moreover, the selected ANN gave better estimation capabilities throughout the range of variables than RSM. Based on the models and the related experimental conditions, the optimal values of each parameter were determined. Under optimum conditions, DEET and total organic carbon (TOC) followed pseudo‐first order kinetics. Nearly complete degradation of DEET took place within 15 min whereas high TOC removal percentages (>85%) was achieved after 90 min irradiation time.     

PERIODIC MARKETS: COMMENTS ON SPATIAL-TEMPORAL RELATIONSHIPS

This work examines the use of an annually updated metropolitan data system as a tool for evaluating benign racial location policies during the first year of the Section 8 Existing Rent Supplement program. Case-study evidence shows that the rent supplement program (with benign locational policies) is ineffective in reducing the isolation faced by minority groups, and that the information used to monitor compliance of the program with benign locational policies lags badly behind the true state of affairs. As a result, new areas of racial concentration have been encouraged and augmented.     

A review of: “National Transfer Format,Release 1.0, January, 1987.” By THE WORKING PARTY TO PRODUCE NATIONAL STANDARDS FOR THE TRANSFER OF NATIONAL DIGITAL MAP DATA. (Southampton: The NTF Secretariat,Ordnance Survey, 1987. [Pp. 191: appendices and looseleaf annex.]

Metonymically used location names (toponyms) refer to other, related entities and thus possess a meaning different from their literal, geographic sense. Metonymic uses are to be treated differently to improve the performance of geographic information retrieval (GIR). Statistics on toponym senses show that 75.06% of all location names are used in their literal sense, 17.05% are used metonymically, and 7.89% have a mixed sense. This article presents a method for disambiguating location names in texts between literal and metonymic senses, based on shallow features.

The evaluation of this method is two‐fold. First, we use a memory‐based learner (TiMBL) to train a classifier and determine standard evaluation measures such as F‐score and accuracy. The classifier achieved an F‐score of 0.842 and an accuracy of 0.846 for identifying toponym senses in a subset of the CoNLL (Conference on Natural Language Learning) data.

Second, we perform retrieval experiments based on the GeoCLEF data (newspaper article corpus and queries) from 2005 and 2006. We compare searching location names in a database index containing both their literal and metonymic senses with searching in an index containing their literal senses only. Evaluation results indicate that removing metonymic senses from the index yields a higher mean average precision (MAP) for GIR. In total, we observed a significant gain in MAP: an increase from 0.0704 to 0.0715 MAP for the GeoCLEF 2005 data, and an increase from 0.1944 to 0.2100 MAP for the GeoCLEF 2006 data.     

Laser-induced breakdown spectroscopy with artificial neural network processing for material identification

Laser-induced breakdown spectroscopy (LIBS) has demonstrated its high potential in measurement of material composition in many areas including space exploration. LIBS instruments will be parts of payloads for the 2011 Mars Science Laboratory NASA-led mission and the ExoMars mission planned by ESA. This paper considers application of artificial neural networks (ANN) for material identification based on LIBS spectra that may be obtained with a portable instrument in ambient conditions. The several classes of materials used in this study included those selected to represent the sites analogues to Mars. In addition, metals and aluminum alloys were used to demonstrate ANN capabilities. Excellent material classification is achieved with single-shot measurements in real time.     

Modelling rock fracturing and blast-induced rock mass failure via advanced discretisation within the discontinuous deformation analysis framework

Rock mass failure is a particularly complex process that involves the opening and sliding of existing discontinuities and the fracturing of the intact rock. This paper adopts an advanced discretisation approach to simulate rock failure problems within the discontinuous deformation analysis (DDA) framework. The accuracy of this approach in continuum analysis is verified first. Then, the advanced discretisation approach for fracturing modelling is presented, and the discretisation strategy is discussed. Sample rock static failures are simulated and the results are compared with experimental results. Thereafter, with a generalised definition of the artificial joints, this approach is further extended and applied in the simulation of blast-induced rock mass failures in which the instant explosion gas pressure obtained by the detonation pressure equation of state is loaded on the main blast chamber walls and the induced surrounding connected fracture surfaces. In the simulation instance of rock mass cast blasting, the whole process, including the blast chamber expansion, explosion gas penetration, rock mass failure and cast, and the formation of the final blasting pile, is wholly reproduced.     

ENVI遥感图像监督分类方法比较

鉴于遥感监督分类方法的普遍应用,本文介绍了五种常用的监督分类方法:平行六面体法、最小距离法、马氏距离法、最大似然法和人工神经网络分类法。就同一地区TM影像应用这五种方法进行了土地利用分类,对比分析了这五种方法的分类精度,发现人工神经网络对土地覆盖与利用的分类精度高于最大似然法,最大似然法分类精度优于平行六面体法、最小距离法和马氏距离法。所得结论对有关遥感图像分类工作具有指导和借鉴意义。