Magnetic survey of topsoils in Windsor–Essex County, Canada

Windsor–Essex County is a major cross-border truck and transportation route, with significant localized industrialization as well as rural and farming areas. Magnetic property measurements (in-field and laboratory susceptibility, frequency-dependent susceptibility, hysteresis properties, thermomagnetic and thermosusceptibility curves, anhysteretic and isothermal magnetizations) were made in order to determine the potential for using such variables to distinguish between natural and anthropogenic pollutants. In-field magnetic susceptibility measured on 324 soil sampling sites on a 0.5–2 km grid spacing through Windsor–Essex County ranged from 3.7 × 10^− 6 to 305.2 × 10^− 6 SI (average 36.2 ± 35.8 × 10^− 6 SI), and showed that high magnetic susceptibility values were obtained on soil sampling sites in and around the cities/towns of Windsor, Harrow, Olinda and Oakland and near the beaches of Point Pelee National Park (PPNP) and Deerbrook, whereas lower susceptibility values were observed in near the towns of Lakeshore and Essex. On this grid spacing, Highway 401 (the major truck route) did not show anomalous susceptibility values; however, closer (1–3 m) sampling on other roads did show anomalously high values, suggesting that the coarser grid spacing may have missed anomalies. Laboratory measurements indicated that the dominant magnetic mineral in the Windsor–Essex County soils is magnetite; however, the grain size is variable. Pseudo-single domain (PSD)–multidomain (MD) magnetite is generally found on beaches and in PPNP, whereas single domain (SD)–PSD magnetite has been found near the City of Windsor and other towns. While certain correlations exist between some anthropogenic activities and the measured magnetic susceptibility and magnetic property values, no overall correlation can be made. A variety of geologic and anthropogenic factors must be considered when interpreting the origin of the magnetic signal in a particular area.     

Synthetic scenario generation of monthly streamflows conditioned to the El Niño–Southern Oscillation: application to operation planning of hydrothermal systems

Stochastic Environmental Research and Risk Assessment - The Brazilian Interconnected Power System is hydro dominated and characterized by large reservoirs presenting multi-year regulation...     

The biodegradation efficiency on diesel oil by two psychrotrophic Antarctic marine bacteria during a two-month-long experiment

Two psychrotrophic bacterial strains isolated from Antarctic seawaters were investigated for their capability to degrade commercial diesel oil. The efficiency of hydrocarbon utilization was studied at 4 and 20 degrees C over a period of two-months. Strains were cultured in a mineral liquid medium supplemented with diesel oil as the sole source of carbon and energy. The viable counts for the bacterial abundance estimation and the culture extractions for the subsequent gas-chromatographic analysis were carried out simultaneously. The biodegradation efficiency was higher at 20 degrees C than at 4 degrees C for both strains and the decrease in hydrocarbon concentrations reached more than 85% after 60 days of incubation at 20 degrees C. Our results suggest the possible exploitation of these two bacterial strains in future biotechnological processes, directly as field-released micro-organisms both in cold and temperate contaminated marine environments.     

青海共和盆地达连海湖泊流域的表土孢粉研究

对青海共和盆地内的达连海湖泊流域54个样点进行植被调查及表土花粉分析,研究了植被与表土花粉之间的关系. 结果显示： 表土花粉组合可反映出该区植被的总体特征;达连海湖泊流域花粉沉积来源于整个流域植被,花粉与主要植被类型之间相关性良好,但不能完全反映出群落的建群种、优势种和盖度等. 蒿属和藜科花粉具有超代表性,禾本科表现为低代表性,蒿/藜比具有区域植被生态特点与气候指示意义,在不同的植被区域A/C变化明显;影响达连海湖泊流域表土花粉组合的主要控制因素是风力作用.     

Seasonal and spatial variations of water quality,substrate and aquatic macrophytes based on side scan sonar,in an eastern Mediterranean lagoon (Kaiafas,Ionian Sea)

Temporal and spatial variations of environmental and water quality parameters and their relations with macrobenthic flora were investigated in an eastern Mediterranean lagoon. Kaiafas is a mesohaline lagoon, which is influenced by point and diffused sources from the adjacent agricultural land and the nearby city. Water samples were analyzed for physicochemical parameters, microbial load and primary production, on a seasonal and spatial scale, while heavy metal concentrations were measured into two different sediment cores. An overall analysis of seasonal dynamics of water parameters and Chl-a based on trophic index TSI pointed out the lagoon as eutrophic. According to water quality parameters the lagoon was separated into two parts. The southern sector of the lagoon which was more affected by human activities showed higher nutrients, Chl-a, heavy metals and total Coliforms concentrations. Sediment texture and distribution of macrophytes were detected through the acoustic side scan sonar method, which proved to be a promising tool for defining and monitoring vegetation coverage of shallow lagoons. A number of distinct echo types and three different sediment types were revealed on the basis of the backscatter level and the variability of low and high backscatter areas. Furthermore, the extension and the coverage of Potamogeton pectinatus and Chara hispida f. corfuensis were successively depicted by combining the data of SSS and ground truthing samples. Meadows of P. pectinatus were established to the lagoon limits where high turbidity and silty substrate occurred, while C. hispida f. corfuensis was limited in deep and high transparent waters with sandy substrate.     

Cross-axis sensitivity of accelerographs with pendulum like transducers—mathematical model and the inverse problem

A mathematical model for a three-component accelerograph is presented that accounts for the effects of transducer misalignment and cross-axis sensitivity. The former refers to departures in the alignment of the transducer penduli (typically of the order of few degrees) from an ideal orthogonal system, and the latter to a transducer recording components of motion in directions other than its principal sensitivity axis. Transducer misalignment magnifies the effects of cross-axis sensitivity. These effects are significant only for large amplitude recordings (peak acceleration close to 1g), for example in the near-field of the 1994 Northridge, California, earthquake. The misalignment angles and the angular amplification constant can be determined by a static tilt test, performed in the field, and solving a generalized inverse problem. This paper presents an algorithm for solution of this inverse problem on a routine basis. Practical implementation of the algorithm and results for 76 instruments of the Los Angeles Strong Motion Array are presented in a separate paper. © 1998 John Wiley & Sons, Ltd.     

Nature, distribution and origin of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Olbia harbor (Northern Sardinia, Italy)

The nature, origin and distribution of US EPA polycyclic aromatic hydrocarbons (PAHs) in the sediments of Olbia harbor (North Sardinia, Italy) were investigated by gas-chromatography/mass spectrometry (GCMS). PAH concentrations in the sediments (SigmaPAHs) ranged from 0.16 to 0.77 microg g(-1), indicating a homogeneously low level of pollution. A rather exceptional prevalence of low molecular weight PAHs was substantiated: nearly 80% of SigmaPAHs include naphthalene (15.19%) and phenanthrene (64.47%). Carcinogenic compounds were present in very low (BaP, BkF, BaA and DBA) or negligible (BbF and Inp) concentrations. As indicated by the Phen/Ant molar ratio, the main source of PAHs is petrogenic, probably due to oil spills from shipping. The low/high molecular weight ratio (ranging between 1.2 and 26) distinguishes the sediments of the tourist harbor from those of the commercial/industrial harbor. Moreover, a slight but meaningful pyrolytic contribution to pollution was found in the tourist harbor, which has the most polluted sediments in the whole harbor. Finally, good linear correlations were found between a selected PAH (Phen and Naph) and selected sums of PAHs (i.e. the total amount of the other 15 US EPA and the sum of low molecular weight PAHs).     

Influence of infill distribution and design typology on seismic performance of low- and mid-rise RC buildings

A growing attention has been addressed to the influence of infills on the seismic behavior of Reinforced Concrete buildings, also supported by the observation of damage to infilled RC buildings after severe earthquakes (e.g. L’Aquila 2009, Lorca 2011). In this paper, a numerical investigation on the influence of infills on the seismic behavior of four different case study buildings is carried out: four- and eight-storey buildings, designed for seismic loads according to the current Italian technical code or for gravity loads only according to an obsolete technical code, are considered. Seismic capacity at two Limit States (Damage Limitation and Near Collapse) is assessed through static push-over analyses, within the N2 spectral assessment framework. Different infill configurations are considered (Bare, Uniformly Infilled, Pilotis), and a sensitivity analysis is carried out, thus evaluating the influence of main material and capacity parameters on seismic response, depending on the number of storeys and the design typology. Fragility curves are obtained, through the application of a Response Surface Method. Seismic performance is also expressed in terms of failure probability, given a reference time period.     

Grain-size end-members and environmentally sensitive grain-size components: A comparative study in the mud shelf depocenters off southern Brazil

The current study aims to do a comparative analysis of the results obtained with two End-Member(EM)grain-size modeling techniques(AnalySize and BasEMMA)and the Environmental Sensitive Grain-Size(ESGS)modeling for sediment samples collected in the mudbelts of the southern Brazilian shelf.The methods were compared using grain-size data from the south Brazilian shelf,and the results are discussed here.It is the first time that the concept of ESGS,in its present form,is utilized outside China.The results show that despite its relative ease of use,the ESGS is not fully comparable to the EM analyses,and only two grain-size ESGS classes were recognized as analogous to EMs.The comparison of the AnalySize and BasEMMA procedures also revealed significant differences between the techniques.A comparative analysis between the two EM techniques revealed advantages in the BasEMMA,especially in the better correlation of the end-members with the original grain size distribution.The analysis of the geographical distribution of the EM abundances allowed point sources of sandy populations to be recognized as well as the contribution of the Rio de la Plata as a source of silty sediments to be inferred.