Use of rhodizonic acid for rapid detection of root border cell trapping of lead and reversal of trapping with DNase

Premise of the StudyLead (Pb) is a contaminant whose removal from soil remains a challenge. In a previous study, border cells released from root tips were found to trap Pb, alter its chemistry, and prevent root uptake. Rhodizonic acid (RA) is a forensic tool used to reveal gunshot residue, and also to detect Pb within plant tissues. Here we report preliminary observations to assess the potential application of RA in exploring the dynamics of Pb accumulation at the root tip surface. Methods and ResultsCorn root tips were immersed in Pb solution, stained with RA, and observed microscopically. Pb trapping by border cells was evident within minutes. The role of extracellular DNA was revealed when addition of nucleases resulted in dispersal of RA-stained Pb particles. ConclusionsRA is an efficient tool to monitor Pb-root interactions. Trapping by border cells may control Pb levels and chemistry at the root tip surface. Understanding how plants influence Pb distribution in soil may facilitate its remediation.U.S. National Science Foundation [PBI-1457092]Open Access JournalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Glacimarine Sedimentation Processes at Kronebreen and Kongsvegen, Svalbard

Tidewater glaciers deposit sediment at their terminus, thereby reducing the relative water depth. Reduced water depth can lead to increased glacier stability through decreased rates of iceberg calving, glacier thinning and submarine melting. Here we investigate sedimentation processes at the termini of Kronebreen and Kongsvegen, Svalbard. We mapped the fjord floor bathymetry in August 2009 and calculate sedimentation rates based on our bathymetry and that from a similar study in 2005. A grounding-line fan is developing near the current position of the subglacial stream. An older, abandoned grounding-line fan that likely formed between ~1987 and 2001 is degrading near the middle of the ice front. Our findings indicate that sediment gravity flows reduce the height of the sediment mound forming at the glacier terminus. The future impact of glacimarine sedimentation processes on glacier stability will depend on the net balance between the observed gravity flows and sediment deposition

Techno-economic and risk evaluation of a thermal recovery project

Field production data were studied, to derive an overall energy balance for the steamflood, to calculate the steamflood capture efficiency and predict future steamflood performance. Heat-losses due to produced fluids were also calculated. Predicted production schedules from the model were history-matched with field production data The reservoir parameters (porosity, {phi}, net thickness, h{sub n}, initial oil saturation, S{sub oi}, and residual oil saturation, S{sub or}) were evaluated statistically using both Gaussian and triangular distributions. These resulted in distributed recovery predictions. The Gaussian distributions behaved as predicted; but of great importance, the skewed triangular distributions also behaved in much the same manner. The results fit closely with predictions using logical formulas to predict expected values, peak values and standard variations of recoveries. This result is important, for it indicates that complete Monte-Carlo simulations may not be necessary. All steamflood calculations were carried out using a PC-based spreadsheet program. The major results were as follows: The capture efficiency of the Wilmington steamflood was calculated at 60%. This is an acceptable value, taking into account the reservoir geometry and history. The calculated heat balance showed high heat-loss to adjacent formations and through produced fluids. Of the cumulative heat injected at the time of the study, 21% had been lost to vertical conduction and 21% through produced fluids. Predicted production schedules indicated that up to 43% of the oil in place (at steamflood initiation) could be recovered by the steamflood

Teleworking practice in small and medium-sized firms: Management style and worker autonomy

In an empirical study of teleworking practices amongst small and medium-sized enterprises (SMEs) in West London, organisational factors such as management attitudes, worker autonomy and employment flexibility were found to be more critical than technological provision in facilitating successful implementation. Consequently, we argue that telework in most SMEs appears as a marginal activity performed mainly by managers and specialist mobile workers

CT imaging techniques for two-phase and three-phase in-situ saturation measurements

The aim of this research is to use the SUPRI 3D steam injection laboratory model to establish a reliable method for 3-phase in-situ saturation measurements, and thereafter investigate the mechanism of steamflood at residual oil saturation. Demiral et al. designed and constructed a three dimensional laboratory model that can be used to measure temperature, pressure and heat loss data. The model is also designed so that its construction materials are not a limiting factor for CT scanning. We have used this model for our study. In this study, we saturated the model with mineral oil, and carried out waterflood until residual oil saturation. Steamflood was then carried out. A leak appeared at the bottom of the model. Despite this problem, the saturation results, obtained by using 2-phase and 3-phase saturation equations and obtained from the Cat scanner, were compared with the saturations obtained from material balance. The errors thus obtained were compared with those obtained by an error analysis carried out on the saturation equations. This report gives details of the experimental procedures, the data acquisition and data processing computer programs, and the analysis of a steamflood experiment carried out at residual oil saturation

CT measurements of two-phase flow in fractured porous media

The simulation of flow in naturally fractured reservoirs commonly divides the reservoir into two continua - the matrix system and the fracture system. Flow equations are written presuming that the primary flow between grid blocks occurs through the fracture system and that the primary fluid storage is in the matrix system. The dual porosity formulation of the equations assumes that there is no flow between matrix blocks while the dual permeability formulation allows fluid movement between matrix blocks. Since most of the fluid storage is contained in the matrix, recovery is dominated by the transfer of fluid from the matrix to the high conductivity fractures. The physical mechanisms influencing this transfer have been evaluated primarily through numerical studies. Relatively few experimental studies have investigated the transfer mechanisms. Early studies focused on the prediction of reservoir recoveries from the results of scaled experiments on single reservoir blocks. Recent experiments have investigated some of the mechanisms that are dominant in gravity drainage situations and in small block imbibition displacements. The mechanisms active in multiphase flow in fractured media need to be further illuminated, since some of the experimental results appear to be contradictory. This report describes the design, construction, and preliminary results of an experiment that studies imbibition displacement in two fracture blocks. Multiphase (oil/water) displacements will be conducted at the same rate on three core configurations. The configurations are a compact core, a two-block system with a 1 mm spacer between the blocks, and a two-block system with no spacer. The blocks are sealed in epoxy so that saturation measurements can be made throughout the displacement experiments using a Computed Tomography (CT) scanner

Predicting decoherence in discrete models

The general aim of this paper is to supply a method to decide whether a discrete system decoheres or not, and under what conditions decoherence occurs, with no need of appealing to computer simulations to obtain the time evolution of the reduced state. In particular, a lemma is presented as the core of the method.Comment: 8 pages, 2 figure

Fidelity amplitude of the scattering matrix in microwave cavities

The concept of fidelity decay is discussed from the point of view of the scattering matrix, and the scattering fidelity is introduced as the parametric cross-correlation of a given S-matrix element, taken in the time domain, normalized by the corresponding autocorrelation function. We show that for chaotic systems, this quantity represents the usual fidelity amplitude, if appropriate ensemble and/or energy averages are taken. We present a microwave experiment where the scattering fidelity is measured for an ensemble of chaotic systems. The results are in excellent agreement with random matrix theory for the standard fidelity amplitude. The only parameter, namely the perturbation strength could be determined independently from level dynamics of the system, thus providing a parameter free agreement between theory and experiment

Other People’S Money: A Visual Technology for Teaching Corporate Restructuring Cross-Functionally

This article presents a detailed plan for using the movie Other People's Money as an integrative technology to teach organizational behavior and finance concepts crossfunctionally. The movie depicts corporate restructuring issues in a comic manner, while still conveying a message. It incorporates topics such as differing organizational models and perpectives, leadership, managerial goals, and stakeholder needs/wants. It also helps students learn about mergers and acquisitions including topics like takeovers, tender offers, and greenmail while stimulating thinking aout complex ethical issues. This teaching tool can be incorporated in undergraduate or graduate business classes, or as a module for management education in corporate settings. The teaching notes include a vocabulary list, suggested stopping points with discussion questions, and a set of postmovie questions to reinforce related concepts and motivate further study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68685/2/10.1177_105256299902300106.pd