Use of cultivar resistance and crop rotation with Bacillus subtilis for clubroot control in canola

Non-Peer ReviewedThis study was conducted to assess additional strategies potentially complimentary to cultivar resistance or biocontrol in control of clubroot. New granular Bacillus subtilis formulations and a seed dressing method were developed to facilitate biofungicide delivery in field trials. The granular formulations were applied in furrow during seeding at 50 kg/ha to a clubroot resistant (CR) and susceptible (CS) canola cultivar, respectively, in three field trials. The seed dressing applied approximately 1×105 to 5×106 cfu/seed doses of the biocontrol agent, and was evaluated on the CS cultivar seeded to different crop-rotation scenarios where the plots had a 1-year, 3-year, or 11-year break from last canola crop. Clubroot disease pressure was high at all trial sites with disease severity indexes (DSI) ranging from 69% to 98% on the CS cultivar. None of the granular formulations reduced clubroot substantially, whereas the CR cultivar showed a high effect, reducing DSI to below 15% and doubling the yield over that of CS cultivar. Plots of varying rotation showed a pattern of clubroot pathogen pressure, with those of 1-year break from canola being the highest. The DSI for all rotational scenarios was high, reaching 100% in short-rotation plots. Biofungicide seed dressing did not reduce DSI, but longer crop rotation often reduced gall size slightly, showed much milder above-ground damage, and increased the yield significantly relative to short rotation in two separate trials. Even a 3-year break from canola was highly beneficial, with the yield doubled as opposed to that with only 1-year break from canola

Computational Models of Classical Conditioning guest editors’ introduction

In the present special issue, the performance of current computational models of classical conditioning was evaluated under three requirements: (1) Models were to be tested against a list of previously agreed-upon phenomena; (2) the parameters were fixed across simulations; and (3) the simulations used to test the models had to be made available. These requirements resulted in three major products: (a) a list of fundamental classical-conditioning results for which there is a consensus about their reliability; (b) the necessary information to evaluate each of the models on the basis of its ordinal successes in accounting for the experimental data; and (c) a repository of computational models ready to generate simulations. We believe that the contents of this issue represent the 2012 state of the art in computational modeling of classical conditioning and provide a way to find promising avenues for future model development

Dictionaries and their users

It is only recently that dictionary users have become a central consideration in the design of dictionaries, and this focus has both stimulated and benefited from research into dictionary use. The present contribution reviews the major issues in dictionary design from the user perspective, taking stock of the relevant findings from user research, insofar as such research can assist lexicographers in producing improved lexical tools

Isolation and characterization of surfactants from tar sand process water

A sublation technique was used to isolate soluble surfactants and accompanying species in the aqueous phase from the hot water processing of two Utah tar sands, Asphalt Ridge and Whiterocks. Many structural similarities for the isolated surfactants were observed from IR spectra, however, the amount of sublated material form each tar sand sample differed by almost a factor of three. Seven different organic solvents/ solvent blends were selected with increasing polarity in order to obtain fractions of each of the sublated surfactants. These fractions were analyzed by FTR, MS and NMR.The analyses showed that most fractions obtained from column chromatography still consisted of a mixture of many different compounds with a predominance of carboxylic and hydroxylic moieties. These chromatographic fractions differed with respect to their aromatic nature, and the length of their hydrocarbon chains

Wettability of shale rock as an indicator of fracturing fluid composition

Shales have become one of the main unconventional gas resources in the world. However, physicochemical properties of rocks are still at the center of research. There have been conducted major researches in wettability of shales by fluids and advances in understanding and control of shale rock wettability. Also influence of interfacial phenomena on a production capacity of reservoirs have been made. The aim of this study is to find a relationship between type of fracturing fluid used during shale gas recovery and shale rock wettability. The study is the first step to evaluate conditions, under which wetting occurs most intensely, how it can be controlled by changing a composition of fracturing fluid and how this composition effects the wetting mechanism. We present a characterization of porous materials by a capillary rise method to study shale wettability by water, oil and other fluids. This work describes the experimental contributions to understand the shale rock/fluid interactions through inquire of fluid role in wettability of shale rock

Mobility of shale drill cuttings constituents

This study focuses on the abundance and mobility of metals and trace elements from shale drill cuttings into water, being the main component of the hydraulic fracturing fluid. The relationship between composition of the shale rock and the potential element release during standard water-based leaching tests was characterized by means of X-Ray Fluorescence spectroscopy (XRF). The XRF analysis confirmed the assumption of shales constituents mobility due to the water-rocks interaction. The mobility of studied constituents was expressed by means of variations in content of individual elements. Increased pH of leachates obtained as a result of water based leaching medium indicated releasing of alkaline origin components such as Ca, Rb, Mo, Sr. Measurements of TOC of the leachates indicated low levels of dissolved organic carbon

Carbon dioxide sequestration during shale gas recovery

This paper presents literature on theoretical and practical aspects of gas production from shale using carbon dioxide fracturing. Development of technical and environmental aspects of carbon dioxide fracturing technologies is also considered. Patents applicable to carbon dioxide fracturing are reviewed. In this work experiments were also conducted to verify possibility of carbon dioxide sequestration in the shale gas reservoirs. Carbon dioxide and methane (CH4) storage capacity was measured as Langmuir volumes. The adsorption capacities depend on content of organic matter in the shale rocks and pressure. The obtained results indicate that developing of carbon dioxide fracturing is reasonable