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We revisit three variants of the well-known Stommel diagrams that have been used to summarize knowledge of characteristic scales in time and space of some important hydrologic phenomena and modified these diagrams focusing on spatiotemporal scaling analyses of the underlying hydrologic processes. In the present paper we focus on soil formation, vegetation growth, and drainage network organization. We use existing scaling relationships for vegetation growth and soil formation, both of which refer to the same fundamental length and timescales defining flow rates at the pore scale but different powers of the power law relating time and space. The principle of a hierarchical organization of optimal subsurface flow paths could underlie both root lateral spread (RLS) of vegetation and drainage basin organization. To assess the applicability of scaling, and to extend the Stommel diagrams, data for soil depth, vegetation root lateral spread, and drainage basin length have been accessed. The new data considered here include timescales out to 150 Myr that correspond to depths of up to 240m and horizontal length scales up to 6400 km and probe the limits of drainage basin development in time, depth, and horizontal extent.

In his paper on net primary productivity of terrestrial communities predicted from climatological data, Rosenzweig (1968) argued that variability in productivity is well accounted for by (evapo)-transpiration, and that water from transpiration is, on global scales, the most variable component in the photosynthesis reaction. The goal of this paper is to investigate whether variability in plant growth on local scales and within species is primarily related to transpiration under several scenarios including different terrain curvature, slope aspect, soil characteristics, and climate ranges. We test the hypothesis that this relationship exists because root growth into the surface soil layers (0–2 m) tends to follow paths with minima in resistance, which in turn maximizes water flow and nutrient delivery rates that regulate growth. The set of all connected paths with individual pore-to-pore flow resistances less than a critical, percolating, value forms a cluster with mass fractal dimensionality, df. We propose that roots follow paths through the 2D percolation cluster, defining the set of all optimal flow paths, making the 2D value of df from percolation relevant to root fractal dimensionality. The tortuosity of such optimal paths as defined in percolation theory should then relate root length to root radial extent, linking the parameters of root tortuosity and plant productivity. Our analysis of large data sets across species implies that root radial extent and tree height are both proportional to cumulative transpiration until trees approached maximum height, and their growth rates are proportional to the transpiration rate, not to the moisture content. Local variations in tree height as functions of the variables investigated appear generally consistent with deduced variations in transpiration. Here this correlation is investigated more closely in the context of studies addressing individual tree species.

The fate of water and water-soluble toxic wastes in the subsurface is of high importance for many scientific and practical applications. Although solute transport is proportional to water flow rates, theoretical and experimental studies show that heavy-tailed (power-law) solute transport distribution can cause chemical transport retardation, prolonging clean-up time-scales greatly. However, no consensus exists as to the physical basis of such transport laws. In percolation theory, the scaling behavior of such transport rarely relates to specific medium characteristics, but strongly to the dimensionality of the connectivity of the flow paths (for example, two- or three-dimensional, as in fractured-porous media or heterogeneous sediments), as well as to the saturation characteristics (i.e., wetting, drying, and entrapped air). In accordance with the proposed relevance of percolation models of solute transport to environmental clean-up, these predictions also prove relevant to transport-limited chemical weathering and soil formation, where the heavy-tailed distributions slow chemical weathering over time. The predictions of percolation theory have been tested in laboratory and field experiments on reactive solute transport, chemical weathering, and soil formation and found accurate. Recently, this theoretical framework has also been applied to the water partitioning at the Earth's surface between evapotranspiration, ET, and run-off, Q, known as the water balance. A well-known phenomenological model by Budyko addressed the relationship between the ratio of the actual evapotranspiration (ET) and precipitation, ET/P, versus the aridity index, ET0/P, with P being the precipitation and ET0 being the potential evapotranspiration. Existing work was able to predict the global fractions of P represented by Q and ET through an optimization of plant productivity, in which downward water fluxes affect soil depth, and upward fluxes plant growth. In the present work, based likewise on the concepts of percolation theory, we extend Budyko's model, and address the partitioning of run-off Q into its surface and subsurface components, as well as the contribution of interception to ET. Using various published data sources on the magnitudes of interception and information regarding the partitioning of Q, we address the variability in ET resulting from these processes. The global success of this prediction demonstrated here provides additional support for the universal applicability of percolation theory for solute transport as well as guidance in predicting the component of subsurface run-off, important for predicting natural flow rates through contaminated aquifers.

Species energy theory suggests that, because of limitations on reproduction efficiency, a minimum density of plant individuals per viable species exists and that this minimum correlates the total number of plant individuals N with the number of species S. The simplest assumption is that the mean energy input per individual plant is independent of the number of individuals, making N, and thus S as well, proportional to the total energy input into the system. The primary energy input to a plant-dominated ecosystem is estimated as its Net Primary Productivity (NPP). Thus, species energy theory draws a direct correspondence from NPP to S. Although investigations have verified a strong connection between S and NPP, strong influences of other factors, such as topography, ecological processes such as competition, and historical contingencies, are also at play. The lack of a simple model of NPP expressed in terms of the principal climate variables, precipitation P, and potential evapotranspiration, PET, introduces unnecessary uncertainty to the understanding of species richness across scales. Recent research combines percolation theory with the principle of ecological optimality to derive an expression for NPP(P, PET). Consistent with assuming S is proportional to NPP, we show here that the new expression for NPP(P, PET) predicts the number of plant species S in an ecosystem as a function of P and PET. As already demonstrated elsewhere, the results are consistent with some additional variation due to non-climatic inputs. We suggest that it may be easier to infer specific deviations from species energy predictions with increased accuracy and generality of the prediction of NPP(P, PET). [ABSTRACT FROM AUTHOR]

Soil depth tends to vary from a few centimeters to several meters, depending on many natural and environmental factors. We hypothesize that the cumulative effect of these factors on soil depth, which is chiefly dependent on the process of biogeochemical weathering, is particularly affected by soil porewater (i.e., solute) transport and infiltration from the land surface. Taking into account evidence for a non-Gaussian distribution of rock weathering rates, we propose a simple mathematical model to describe the relationship between soil depth and infiltration flux. The model was tested using several areas in mostly semi-arid climate zones. The application of this model demonstrates the use of fundamental principles of physics to quantify the coupled effects of the five principal soil-forming factors of Dokuchaev.

The essay describes how a combination of scaling theory from percolation, that relates pore scale flow and transport through catchment scales to global scales (bottom‐up), as well as water fluxes to soil formation and vegetation growth, can be used to support an accurate ecological optimization that (top‐down): solves the central problem of hydrology, that is., "the water balance," and generates critically important derived quantities, namely streamflow response to climate change, net primary productivity, and plant species richness. Moreover, the essay describes how this particular theoretical approach came to be designed and how it, in retrospect, fits in with the vision of the Committee on Opportunities in the Hydrologic Sciences which met 34 years ago to formulate a research, teaching, and infrastructure guide for the community, and "rebrand our science as a geoscience." Finally, it demonstrates how the research satisfies the present desires of the community to unite Darwinian and Newtonian scientific methods in the solution of this central problem and how it relates to present research directions in the fields of hydrologic sciences and ecology. [ABSTRACT FROM AUTHOR]

Aims: Our aim was to determine the absolute bioavailability, mass balance, metabolism and excretion of soticlestat (TAK‐935). Methods: An open‐label, two‐period, single‐site, phase 1 study was conducted in six healthy men. In Period 1, a single 300 mg dose of soticlestat was administered orally, followed by a 15‐min intravenous infusion of [14C]soticlestat 50 μg (~1 μCi) 10 min later. In Period 2, a single 300 mg dose (~100 μCi) of [14C]soticlestat in solution was administered orally. Samples were collected, analysed for radioactivity or unchanged soticlestat, and profiled for metabolites. Results: In Period 1, soticlestat had an absolute bioavailability of 12.6% (90% confidence interval, 7.81–20.23%). In Period 2, there was near‐complete recovery of total radioactivity (TRA) following a 300 mg dose of [14C]soticlestat: urine, 94.8% (standard deviation [SD], 1.35%); faeces, 2.7% (SD, 1.67%). Of TRA, 0.1% (SD, 0.09%) and 0.6% (SD, 0.21%) were recovered as soticlestat and metabolite M‐I in urine, respectively. In plasma, soticlestat and M‐I reached geometric mean maximum observed concentrations of 1352 ng/mL (geometric percent coefficient of variation [gCV%], 61.3) and 253.2 ng/mL (gCV%, 44.1) after 25 min and declined with mean terminal half‐lives (SD) of 5.7 (2.90) and 2.0 (0.15) h, respectively. Soticlestat represented 4.9% of TRA in plasma. Soticlestat was rapidly eliminated primarily via O‐glucuronidation to metabolite M3, which was the dominant species in plasma (92.6%) and urine (86%). Conclusions: This study indicates that soticlestat and its metabolites are rapidly cleared and eliminated, lowering the risk of dose accumulation from repeated dosing and supporting further investigation of soticlestat. [ABSTRACT FROM AUTHOR]

Earth's climate has undergone significant fluctuations in the geologic past. We focus on the glacial episodes that followed the major waves of invasion of land plants. Twice in Earth's history the impacts of land plant innovations on the atmosphere through increased CO2 drawdown have precipitated sufficient cooling to produce ice ages. Each time, however, adaptation of soil ecosystems eventually helped re-establish apparent steady-state conditions, i.e., new equilibrium temperature and atmospheric CO2 content, ending each of the glacial episodes. In each case, the time interval between the initial innovation and the emergence from the glacial episode was approximately 60 Myr. The consistency of the time scale of the response invites an explanation in terms of a universal rate of dispersal of genetic information that encapsulates the biogeochemical cycle of cellulose production and decay. In this paper, we postulate that the long time for adaptation is a consequence of the time required for the spread of an entire clade though the soil to continental scale. Although 60 Myr appears to be a long time, it is very short compared to the time required for diffusion to transport even molecules like HCO3- or sugar through the soil over a continental distance of 5,000 km, which is between 1014 and 1016 years for solutes with such soil diffusion constants in the range 10-11 m²s-1. Horizontal solute transport through heterogeneous media by advection might be considered as a dispersal mechanism, but is also known to require enormous time scales (ca. 150 Myr for 500 m). We also seek a relevant mechanism in the known scaling of plant and fungal growth rates as a function of time, which can facilitate as well the movement of bacteria, and predicted these rates theoretically on the basis of the universal optimal 2D paths tortuosity from percolation. Comparison with actual data pairs (7,000) for plant and fungal growth rates were used to verify these predictions over 13 orders of magnitude of time, from about one minute to 100 kyr; extrapolation over less than three additional orders of time yields a continental-scale transport time of 80 Myr. We now interpret this prediction in terms of Margulis' understanding of emergent behavior of coupled (soil and plant) ecosystems responding to climate shocks induced by plant innovations. [ABSTRACT FROM AUTHOR]

Futibatinib, a selective, irreversible fibroblast growth factor receptor 1–4 inhibitor, was recently approved for FGFR2 rearrangement–positive cholangiocarcinoma. This Phase I study evaluated the mass balance and metabolic profile of 14C‐futibatinib single oral 20‐mg dose in healthy participants (n = 6). Futibatinib was rapidly absorbed; median time to peak drug concentration was 1.0 hours. The mean elimination half‐life in plasma was 2.3 hours for futibatinib, and 11.9 hours for total radioactivity. Mean recovery of total radioactivity was 70% of the dose, with 64% recovered in feces and 6% in urine. The major excretion route was fecal; negligible levels were excreted as parent futibatinib. Futibatinib was the most abundant plasma component, comprising 59% of circulating radioactivity (CRA). The most abundant metabolites were cysteinylglycine‐conjugated futibatinib in plasma (13% CRA) and reduction of desmethyl futibatinib in feces (17% of dose). In human hepatocytes, 14C‐futibatinib metabolites included glucuronide and sulfate of desmethyl futibatinib, whose formation was inhibited by 1‐aminobenzotriazole (a pan‐cytochrome P450 inhibitor), and glutathione‐ and cysteine‐conjugated futibatinib. These data indicate the primary metabolic pathways of futibatinib are O‐desmethylation and glutathione conjugation, with cytochrome P450 enzyme‐mediated desmethylation as the main oxidation pathway. 14C‐futibatinib was well tolerated in this Phase 1 study. [ABSTRACT FROM AUTHOR]