Thermal and force-chain effects in the granular slope experiments of Roering et al. (2001) and Roering (2004) (2007): A simple scalinng of the forces involved in the granular motion in these experiments (Roering et al., 2001, Geology, 29, 143-146; Roering, 2004, Earth Surf. Proc. Land., 29, 1597-1612) suggests that this shearing motion reflects a balance between the rate of production and the rate of disruption of granular force chains.
Rainsplash transport as a novel advection-dispersion process (2007): This describes our efforts to show why soil grain transport by rainsplash is fundamentally an advection-dispersion process. The formulation indicates that gradients in raindrop intensity, and thus grain activity, can be as important as gradients in grain concentration and surface slope in effecting transport.
A logistic equation with resource-modulated carrying capacity (2007): This brief analysis reformulates the classic logistic equation using a Michaelis-Menten description for the rate of nutrient uptake by algae. The formulation offers a new spin on the concept of carrying capacity such that this capacity is, like reproduction, modulated by nutrient availability.
Probabilistic formulation of the Exner sediment continuity equation and the bedload flux for the case of uniform sediment (2006): This is a quick cut at meshing our ongoing interest in probabilistic formulations of sediment particle motions with the related work of Parker et al. (2000, J. Hydraul. Eng., 126, 818-826) and Nikora et al. (2002, Wat. Res. Res., 38, 1081). Important details need to be filled in.
Do Hexagenia (Mayfly larvae) garden their burrows? (2006): This brief analysis, inspired by discussions with Brooke Traynham and Molly Miller, develops the hypothesis that Hexagenia harvest bacteria that colonize their burrows, and suggests the possibility that an "optimal" burrow length exists which balances bacteria production against energy spent in maintaining flow through the burrow.
Nitrogen spiraling in a stream (2005): These notes, inspired by discussions with Mary Power, are a quick look at nitrogen uptake and release by benthic algae, based on a modified Michaelis-Menten formulation of uptake.
Obtaining soil flux from integration of the soil production rate (2005): This is the appendix for the paper by Heimsath et al. (2005, Geology, 33, 949-952), describing the conditions under which transient soil storage can be neglected in estimating the soil flux at arbitray hillslope position by integrating the soil production rate upslope.
Fluid-mechanical insights on gravity-driven intrusion of mafic magma into a felsic host: Development of mafic-felsic layering punctuated by felsic pipes (2005): This contains supporting theory for work inspired by Calvin Miller and his students accompanying field observations and our scaled tank experiments involving intrusion of dense low-viscosity glycerine into less dense high-viscosity silicon gel.
Cool algae and zooplankton behavior according to ideas of Jim Morris (2004): These notes, inspired by discussions with Jim Morris, are a quick look at how algae (the prey) and zooplankton (the predator) might interact in a river-estuarine setting in relation to differences in characteristic reproductive and consumptive timescales, modulated by spatially varying advective flow timescales.
Interactions between seasonal particulate organic matter (POM) loading and flow in a stream (2004): This simple analysis suggests that in-stream POM depends significantly on the timing of high flows relative to the seasonal POM loading.
Tidally induced groundwater circulation in an unconfined coastal aquifer modeled with a Hele-Shaw cell (2004): This is the appendix for the paper by Mango et al. (2004, Geology, 32, 233-236), providing the full justification for the use of a Hele-Shaw cell to mimic nearshore groundwater motions, and clarifying why hydrostatic conditions do not exist in this natural setting.
Conservation of mass of soil-mantled hillslopes (2003): These notes, inspired by discussions with Bill Dietrich, formulate the vertically-integrated equations of soil-mass conservation, showing how the soil thickness becomes a key length scale in the vertically-integrated soil flux, how tectonic motions appear as advective source terms, and how soil production from bedrock explicitly enters the mass balance as a local source term. A more general version of this formulation, including effects of chemical denudation, appears in Mudd and Furbish (2004, JGR–ES, 109, F02001); the most general formulation is provided by Paola and Voller (2005, JGR–ES, 110).
