Dissolved and particulate trace metals in a Scottish sea loch: an example of a pristine environment?

In the near pristine environment of a silled fjord on the west coast of Scotland samples were taken for the determination of dissolved and particulate trace metals (Fe, Mn, Cu, Ni, Cd, Zn and Pb), together with nutrient and hydrographic data, during 19 surveys carried out over a year. An indication of the pristine nature of the environment are the low concentrations of dissolved silicon, phosphate and nitrate which are considerably lower than those of coastal waters which are subject to larger anthropogenic burdens. Distributions of dissolved Cu, Ni and Cd were found to broadly reflect conservative mixing of freshwater and seawater with both end members having similar concentrations. The concentration of dissolved Cu and Ni in seawater entering upper Loch Linnhe (Cu 0.28 μg l⁻¹; Ni 0.26 μg l⁻¹) was consistent with the 1:1 conservative mix of Irish Sea water and North Atlantic surface water predicted from radio-caesium tracer experiments (Mackay & Baxter, 1985). Atmospheric input of trace metals to upper Loch Linnhe appeared to be a relatively minor term in the mass balance relative to fluvial inputs. Values of distribution coefficients Kd were similar to those previously reported for the coastal environment. Iron showed the strongest affinity for the suspended sediments; with particulate percentages of the total load usually greater than 80%. Lead and Mn showed a similar strong affinity to the particle phase. For Cu, Ni and Zn the mass of the element in the dissolved phase was generally greater than that in the particulate fraction. Cadmium, was least associated with the particles, with typically greater than 90% existing in the dissolved phase.     

Two field applications of the rotating current EM method1

The rotating current EM method has been applied to the delineation of two conductive orebodies, Elura near Cobar, NSW, and Thalanga near Charter's Towers, Queensland. The field data were collected in the form of observations of the vertical magnetic field strength ratio and phase difference using a Turam-style receiver with twin vertical coils. By reconstituting this data back to the ring source field and phase, i.e. the observed H_z, phasor, it is possible to present contoured maps of the EM field. Anomaly phasors are obtained by subtracting theoretical phasors from the observed phasors in the complex plane of the H_z phasor. The theoretical phasors for the finite source are based on horizontally layered, half-space earth models, computed at each point of the survey grids, then normalized to selected points of the observed fields. Use is made of the intrinsic circular symmetry of the method in X–Y plots of field versus source-receiver distance to ascertain geoelectric parameters for the earth models. A steel picket fence at Thalanga is modelled by a line source grounded at each end and its H_z, phasor is removed by the same process. A considerable improvement in anomaly delineation is gained over previous Turam-style anomalies and the two survey examples illustrate the limitations of the method in the presence of a conductive overburden (Elura) and its abilities in the absence of a conductive overburden (Thalanga).     

Social network interactions among mentally ill persons in community housing: research issues and agenda

This paper discusses social network interactions among individuals who have been hospitalized with mental illness and who currently reside in different types of community housing programmes. First, a conceptualisation of social networks that focuses on network interactions, both supportive and non-supportive, between network interactions may be more important influences on successful or unsuccessful adaptation of current and former psychiatric patients to community life than the structural dimensions of social networks more commonly analysed in the literature. The design of a current longitudinal study of social network interactions is presented. The results of two pilot studies that examine social network interactions is presented. The results of two pilot studies that examine social network interactions with data from several community housing programmes in southern Ontario, Canada are reviewed and an agenda is stated for further data collection and analysis.     

The relationship between geothermal gradient and the composition of granitic magmas in orogenic belts

A comparison has been made between the average compositions of the granites in the Variscan, Caledonian, and Alpine orogenic belts of western Europe. Their respective compositions lie near the isobaric minima in the system Q-Or-Ab-H₂O for successively higher water pressures, whereas metamorphic facies series indicate that the three orogenic belts developed under successively lower geothermal gradients. These relationships are consistent with an origin of the granitic magmas by partial melting in the crust.     

Some exact solutions of unsteady boundary layer equations-I

Summary Unsteady boundary layer flows generated in a homogeneous, non-rotating viscous fluid are considered. The method of Laplace transform is used to obtain exact solutions of the unsteady boundary layer equations in a more general situation. The structures of the unsteady velocity field and the associated boundary layers are determined. Several particular solutions are recovered as special cases of the present general theory. The physical implications of the mathematical results are investigated.     

Experimental test of the wind-shear theory. A reply—rocket-borne magnetometers do measure B

The apparent inconsistencies noted by Whitehead ⁽¹⁾ in the ionization, electron density, wind and magnetic field data of the rocket flights SL 130 and 131 (Hall et al. ⁽²⁾) are resolved by the presentation of further experimental detail. Observational accuracy and in particular the heading correction procedure for the magnetic field values are discussed. It is also pointed out that the interaction of the steady EW wind component with the E _g ionization profile provides an additional contribution to the E _g magnetic field. It is concluded that within the experimental limitations the experiment remains a fair test of the wind-shear theory.     

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System identification of a concrete arch dam and calibration of its finite element model

A magnitude 4.3 earthquake occurred near Pacoima Dam on 13 January 2001. An accelerometer array that had been upgraded after the Northridge earthquake recorded the motion with 17 channels on the dam and the dam–foundation interface. Using this data, properties of the first two modes are found from a system identification study. Modal properties are also determined from a forced vibration experiment performed in 2002 and indicate a significantly stiffer system than is estimated from the 2001 earthquake records. The 2001 earthquake, although small, must have induced temporary nonlinearity. This has implications for structural health monitoring. The source of the nonlinear behaviour is believed to be loss of stiffness in the foundation rock. A finite element model of Pacoima Dam is constructed and calibrated to match modal properties determined from the system identification study. A dynamic simulation of the 2001 earthquake response produces computed motions that agree fairly well with the recorded ones. Copyright © 2006 John Wiley & Sons, Ltd.