Metabolite-driven mechanisms reveal chemical ecology of Lehmann Lovegrass (Eragrostis lehmanniana) invasion in North American semi-arid ecosystems.

Invasive plants threaten global ecosystems, yet traditional analyses of functional traits cannot fully explain their dominance over co-occurring natives. Metabolomics offers insights into plant invasions, but single-technique studies often miss critical biochemical mechanisms. We employ a multimodal metabolomics approach (¹H NMR, LC MS/MS, FT-ICR-MS, and MALDI-MSI) to investigate the biochemical basis of Lehmann lovegrass (Eragrostis lehmanniana) invasion in semi-arid North America, comparing it with a co-occurring native grass, Arizona cottontop (Digitaria californica).

Effects of Stockpiling on Topsoil Biogeochemistry for Semiarid Mine Reclamation.

Unlabelled: Stockpiling and storage of topsoil for use in reclamation and revegetation are common practices for many mining operations. However, stockpiling can lead to significant changes in topsoil physical and biogeochemical properties that may be detrimental to reclamation. The objective of this research was to assess the effect of long-term stockpiling on soil biogeochemical properties in a semiarid region.

Beyond bulk: Density fractions explain heterogeneity in global soil carbon abundance and persistence.

Understanding the controls on the amount and persistence of soil organic carbon (C) is essential for predicting its sensitivity to global change. The response may depend on whether C is unprotected, isolated within aggregates, or protected from decomposition by mineral associations. Here, we present a global synthesis of the relative influence of environmental factors on soil organic C partitioning among pools, abundance in each pool (mg C g  soil), and persistence (as approximated by radiocarbon abundance) in relatively unprotected particulate and protected mineral-bound pools.

Model cortical association fields account for the time course and dependence on target complexity of human contour perception.

Can lateral connectivity in the primary visual cortex account for the time dependence and intrinsic task difficulty of human contour detection? To answer this question, we created a synthetic image set that prevents sole reliance on either low-level visual features or high-level context for the detection of target objects. Rendered images consist of smoothly varying, globally aligned contour fragments (amoebas) distributed among groups of randomly rotated fragments (clutter). The time course and accuracy of amoeba detection by humans was measured using a two-alternative forced choice protocol with self-reported confidence and variable image presentation time (20-200 ms), followed by an image mask optimized so as to interrupt visual processing.

Surface tension of quantum fluids from molecular simulations.

We present the first molecular simulations of the vapor-liquid surface tension of quantum liquids. The path integral formalism of Feynman was used to account for the quantum mechanical behavior of both the liquid and the vapor. A replica-data parallel algorithm was implemented to achieve good parallel performance of the simulation code on at least 32 processors.