Modification of the simple mass balance equation for calculation of critical loads of acidity.

Over the last few years, the simple mass balance equation for the calculation of critical loads of acidity has been gradually modified as the underlying critical load concepts have developed and as problems with particular forms of the equation have been identified, through application in particular countries. The first major update of the equation took place following a workshop held in Vienna, Austria (Hojesky et al. 1993). The workshop was held to discuss problems which had been identified when the then current form of the equation was applied in countries with high rainfall. The problems had largely arisen because of simplifications and assumptions incorporated into the early formulation of the equation. The equation was reformulated to overcome the problems identified at the workshop. However, further problems were identified when the reformulated equation was applied in the UK in situations with a combination of high rainfall, large marine inputs and widespread occurrence of organic soils. A small workshop was, therefore held in Grange-over-Sands, UK in late 1993 to dicuss the problems and to further re-evaluate the equation. The problems had arisen in the UK because of simplifications and assumptions made in the formulation concerning, in particular, cation leaching and uptake. As a result, a more rigorous treatment of these variables was incorporated into the equation. The reformulation of the equation, as derived at the September 1993 workshop is described below

Sensorimotor temporal recalibration within and across limbs

Deciding precisely when we have acted is challenging, as actions involve a train of neural events spread across both space and time. Repeated delays between actions and consequent events can result in a shift, such that immediate feedback can seem to precede the causative act. Here we examined which neurocognitive representations are affected during such sensorimotor temporal recalibration, by testing if the effect generalizes across limbs and whether it might reflect altered decision criteria for temporal judgments. Hand or foot adaptation phases were interspersed with simultaneity judgments about actions involving the same or opposite limb. Shifts in the distribution of participants' simultaneity responses were quantified using a detection-theoretic model, where a shift of both boundaries together gives a stronger indication that the effect is not simply a result of decision bias. By demonstrating that temporal recalibration occurs in the foot as well as the hand, we confirmed that it is a robust motor phenomenon: Both low and high boundaries shifted reliably in the same-limb conditions. However, in cross-limb conditions only the high boundary shifted reliably. These two patterns are interpreted to reflect a genuine change in how the time of action is represented, and a timing criterion shift, respectively. (PsycINFO Database Record (c) 2013 APA, all rights reserved)

Hydrologic Transport of Dissolved Inorganic Carbon and Its Control on Chemical Weathering

Chemical weathering is one of the major processes interacting with climate and tectonics to form clays, supply nutrients to soil microorganisms and plants, and sequester atmospheric CO2. Hydrology and dissolution kinetics have been emphasized as factors controlling chemical weathering rates. However, the interaction between hydrology and transport of dissolved inorganic carbon (DIC) in controlling weathering has received less attention. In this paper, we present an analytical model that couples subsurface water and chemical molar balance equations to analyze the roles of hydrology and DIC transport on chemical weathering. The balance equations form a dynamical system that fully determines the dynamics of the weathering zone chemistry as forced by the transport of DIC. The model is formulated specifically for the silicate mineral albite, but it can be extended to other minerals, and is studied as a function of percolation rate and water transit time. Three weathering regimes are elucidated. For very small or large values of transit time, the weathering is limited by reaction kinetics or transport, respectively. For intermediate values, the system is transport controlled and is sensitive to transit time. We apply the model to a series of watersheds for which we estimate transit times and identify the type of weathering regime. The results suggest that hydrologic transport of DIC may be as important as reaction kinetics and dilution in determining chemical weathering rates

Note on the correlation of reversing thermometers

Corrections have to be applied to the readings of protected and unprotected reversing thermometers because they are read at a temperature that differs from that at the time of reversal. In deriving these corrections it is generally assumed that Feruglio\u27s (1912) equation [(5) below] is exact. It is shown here that Feruglio\u27s equation is not quite exact, but a close approximation. From this equation practical formulae, equations (6) and (8) below, can be derived very simply without further sacrifice of accuracy

Lateral mixing in the deep water of the South Atlantic Ocean

The deep-sea circulation of the Atlantic has recently been carefully analyzed by Wiist (1935) who, on the basis of the tongue-like distribution of temperature and salinity, has drawn conclusions as to the direction of flow at different depths. He considers that an exchange of deep :water between the North Atlantic Ocean and the Antarctic Ocean is maintained by a flow to the north along the bottom of Antarctic water and a flow to the south at lesser depths of North Atlantic deep water and Mediterranean water

On the process of upwelling

The phenomenon of upwelling which is present along many coasts has been discussed from various points of view. A general explanation of the phenomenon has been given by application of Ekman\u27s theory of winddriven currents (Thorade, 1909; McEwen, 1912), and emphasis has been put on the velocity of the vertical motion (McEwen, 1934) or on the depth from which water is brought to the surface (Gunther, 1936; Sverdrup, 1930)...

O\u27Brien v. Great No. Ry., 400 P.2d 634 (Mont. 1965)

O\u27Brien v. Great No. Ry