Event category learning.

This research investigated the learning of event categories, in particular, categories of simple animated events, each involving a causal interaction between 2 characters. Four experiments examined whether correlations among attributes of events are easier to learn when they form part of a rich correlational structure than when they are independent of other correlations. Event attributes (e.g., state change, path of motion) were chosen to reflect distinctions made by verbs. Participants were presented with an unsupervised learning task and were then tested on whether the organization of correlations affected learning. Correlations forming part of a system of correlations were found to be better learned than isolated correlations. This finding of facilitation from correlational structure is explained in terms of a model that generates internal feedback to adjust the salience of attributes. These experiments also provide evidence regarding the role of object information in events, suggesting that this role is mediated by object category representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mineral and trace element composition of the Lokpanta oil shales in the Lower Benue Trough, Nigeria

The concentrations of minerals and trace elements in the Lokpanta oil shale from the Lower Benue Trough, Nigeria have been determined by X-ray diffraction (XRD) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), respectively. X-ray diffraction data were evaluated using the SIROQUANT™ interactive data processing system based on Rietveld interpretation methods. A new method of trace element determination in oil shale, involving LA-ICP-MS analysis of glass beads prepared by fusing oil shale ash on an iridium strip heater was used, and the accuracy of the method was assessed by including a standard shale reference material (SGR-1b) in the analysis program.The minerals in the raw oil shales are mainly quartz, calcite and clay minerals, with the latter being represented by kaolinite and interstratified illite/smectite. Ashes of the oil shale samples prepared at 815 °C have quartz and (in some cases) illite as the dominant mineral phases, along with a significant proportion of amorphous materials. The Lokpanta oil shales are highly enriched in some potentially hazardous trace elements, including V, Cr and Ni, when compared with oil shales from other deposits around the world. The results obtained for the trace elements in the reference material show that the LA-ICP-MS method described in this study is very accurate and precise for the determination of a wide range of trace elements in oil shales.     

Mechanistic studies of proteases and lipases for the detergent industry

The wash performance of three specific proteases (asp, lys/arg and glu specific, respectively) is demonstrated to be comparable to that of commercial unspecific detergent proteases (Alcalase® and Savinase®). A hypothesis for the high performance of these specific proteases is proposed. The influence of pH and ionic strength on protease performance is discussed. The removal of oily stains by lipases in detergent solution is improved only slightly under acidic conditions, whereas pH values >> pK_a of the fatty acids formed results in strongly enhanced removal. Wash trials with Lipolase^TM show very little effect of the lipase after the first wash, but high effect after the second and subsequent washes. This is explained by lipolytic activity under drying. Maximum activity is found when the water content of the cotton swatches is between 10 and 40% (w/w).     

Bacterial community dynamics,lactic acid bacteria species diversity and metabolite kinetics of traditional Romanian vegetable fermentations

BACKGROUND: Artisanal vegetable fermentations are very popular in Eastern European countries. Fresh vegetables undergo a spontaneous fermentation in the presence of salt, which is mainly carried out by lactic acid bacteria (LAB). RESULTS: Culture‐dependent and culture‐independent analyses of end‐samples of various spontaneous vegetable fermentations carried out in houses of the Chiodju region (central Romania) revealed Lactobacillus plantarum and Lactobacillus brevis as the most frequently isolated LAB species. Leuconostoc mesenteroides and Leuconostoc citreum were also found. Furthermore, the community dynamics of spontaneous cauliflower and mixed‐vegetable (green tomatoes, carrots and cauliflower) fermentations revealed three steps: an initial phase characterised by the presence of Enterobacteriaceae and a wide LAB species diversity, encompassing Weissella species; a second phase from day 3 onwards wherein L. citreum and Lb. brevis occurred; and a final phase characterised by the prevalence of Lb. brevis and Lb. plantarum. Metabolite target analysis revealed that glucose and fructose were mostly depleted at the end of fermentation. The main products of carbohydrate metabolism were lactic acid, acetic acid, ethanol and small amounts of mannitol, indicating heterolactate fermentation. CONCLUSION: Given their prevalence at the end of vegetable fermentations, Lb. brevis and Lb. plantarum appear to be good candidate starter cultures for controlled vegetable fermentation processes. © 2012 Society of Chemical Industry     

The CACHE Study: Group Effects in Computer-supported Collaborative Analysis

The present experiment investigates effects of group composition in computer-supported collaborative intelligence analysis. Human cognition, though highly adaptive, is also quite limited, leading to systematic errors and limitations in performance – that is, biases. We experimentally investigated the impact of group composition on an individual’s bias, by composing groups that differ in whether their members initial beliefs are diverse (heterogeneous group) or similar (homogeneous group). We study three-member, distributed, computer-supported teams in heterogeneous, homogeneous, and solo (or nominal) groups. We measured bias in final judgment, and also in the selection and evaluation of the evidence that contributed to the final beliefs. The distributed teams collaborated via CACHE-A, a web-based software environment that supports a collaborative version of Analysis of Competing Hypotheses (or ACH, a method used by intelligence analysts). Individuals in Heterogeneous Groups showed no net process cost, relative to noninteracting individuals. Both heterogeneous and solo (noninteracting) groups debiased strongly, given a stream of balanced evidence. In contrast, individuals in Homogenous Groups did worst, accentuating their initial bias rather than debiasing. We offer suggestions about how CACHE-A supports collaborative analysis, and how experimental investigation in this research area can contribute to design of CSCW systems.     

Chemical characterization by gas chromatography-mass spectrometry and inductively coupled plasma-optical emission spectroscopy of membrane permeates from an industrial dairy ingredient production used as process water

Reusing reverse osmosis (RO) membrane permeate instead of potable water in the dairy industry is a very appealing tactic. However, to ensure safe use, the quality of reclaimed water must be guaranteed. To do this, qualitative and quantitative information about which compounds permeate the membranes must be established. In the present study, we provide a detailed characterization of ultrafiltration, RO, and RO polisher (ROP) permeate with regard to organic and inorganic compounds. Results indicate that smaller molecules and elements (such as phosphate, but mainly urea and boron) pass the membrane, and a small set of larger molecules (long-chain fatty acids, glycerol-phosphate, and glutamic acid) are found as well, though in minute concentrations (<0.2 µM). Growth experiments with 2 urease-positive microorganisms, isolated from RO permeate, showed that the nutrient content in the ROP permeate supports limited growth of 1 of the 2 isolates, indicating that the ROP permeate may not be guaranteed to be stable during protracted storage.     

Unsupervised concept learning and value systematicitiy: A complex whole aids learning the parts.

Ease of learning new concepts may best be understood by simultaneously considering models of learning and theories of how "good" systems of categories are organized. The authors tested the effects on learning of value systematicity, a proposed organizing principle: If 1 attribute is predictive of another, it should predict still more. This principle derives from focused sampling in the internal feedback model (D. Billman & E. Heit, 1988) of unsupervised, or observational, learning. In 3 experiments, the authors tested how the organization of structure in input (value systematicity) affected unsupervised learning of categories about alien animals. Across all experiments, learning a target rule was easier in conditions with high value systematicity, relative to several low systematicity controls. The authors compare results to predictions of several learning models and consider the links between learning and the resulting category structure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acquiring and Combining Overlapping Concepts

This article presents OLOC, an incremental concept formation system that learns and uses overlapping concepts. OLOC learns probabilistic concepts that have overlapping extensions and does so to maximize expected predictive accuracy. When making predictions, OLOC can combine multiple overlapping concepts.