Effects of a diesel spill on freshwater macroinvertebrates in two urban watercourses,Wiltshire, UK

The impacts of a spill of approximately 9800 L of diesel on a small stream and the River Ray (near Swindon, Wiltshire, UK) were examined using kick-net sampling of freshwater macroinvertebrate families at impacted and reference sites. Initial impacts (10 days after the spill) 50 m downstream of the spill were severe, with only 9% survival of individuals (excluding oligochaete worms) and 56% survival of invertebrate families. The percentage survival of macroinvertebrates increased progressing downstream from the spill, with no detectable impacts beyond approximately 4 km downstream. The crustacean families Asellidae and Gammaridae were particularly sensitive to the diesel spill. The recovery of the macroinvertebrate community was assessed 13.5 months after the spill. At this time, recovery was almost complete, with only minor impacts at the sites closest to the spill. The use of live laboratory sorting of samples from impacted sites provided essential information on the impacts of the diesel spill.     

Stability of the mycotoxin deoxynivalenol (DON) during the production of flour-based foods and wheat flake cereal

Deoxynivalenol (DON) is a mycotoxin found in cereal grains and cereal-based foods. DON concentrations in finished products are reduced under some processing conditions, but not others. DON concentrations in flour, wheat and selected foods made from them under commercially relevant conditions were compared by GC with electron capture detection. Average concentrations (n = 9/item) in cookies, crackers and pretzels ranged from 61% (cookies) to 111% (pretzels) compared with flour (100% = 0.46 μg g?1). Lesser amounts were found in donuts and bread: their respective DON concentrations were 44% and 30% that of flour. Mass balance estimates for DON (μg g?1 flour equivalents) ranged from 50% (bread = 0.23 μg g?1 flour equivalents) to 120% (donuts), indicating that dilution by recipe ingredients contributed to DON reductions in bread and accounted for all of the apparent reduction in donuts. Mass balance estimates averaged 76% (crackers) to 107% (pretzels) for the other flour products. DON concentrations were higher in cereal flakes (0.55 μg g?1 in the finished product and 0.58 μmg g?1 on a mass balance basis) than in wheat (0.40 μg g?1), suggesting that DON concentrations might increase during processing of wheat cereals under some conditions. In summary, DON concentrations of finished food products were reduced ≥ 50% only in bread and donuts. Reduction in bread resulted from a combination of DON ‘loss’ and dilution by recipe ingredients whereas the reduction in donuts was due entirely to dilution. These results are further evidence of DON stability during the preparation of popular flour or wheat-based products.     

High-frequency ultrasound annular-array imaging. Part I: array design and fabrication

This is Part I of a series of two papers describing the development of a digital high-frequency, annular-array, ultrasonic imaging system. In this paper, the design and fabrication of a high-frequency annular array as well as its performance will be reported. A six-element, 50 MHz array, which incorporated an acoustic lens to provide an initial focal point, was designed and fabricated. A submicron size grain lead titanate piezoelectric ceramic was used to both reduce lateral coupling and keep the electrical impedance matched close to the 50 ohm receive electronics. The array elements were isolated using laser micromachining to fully separate the annuli, and electrical interconnection was achieved by directly soldering thin wires to the elements. The resulting array attained an average impulse response that exhibited a 43 MHz center frequency, 30% relative bandwidth, and an average insertion loss of 31 dB at 45 MHz. Maximum next-element crosstalk was -27 dB in water.     

Modelling the role of size, edge structure and terminations on the electronic properties of trigonal graphene nanoflakes

Graphene nanoflakes provide a range of opportunities for engineering graphene for future applications, due to the large number of configurational degrees of freedom associated with the addition of different types of corners and edge states in the structure. Since these materials can, in principle, span the molecular to macroscale dimensions, the electronic properties may also be discrete or continuous, depending on the application in mind. However, since the widespread use of graphene nanoflakes will require them to be predictable, stable and robust against variations associated with some degree of structural polydispersivity, the development of a complete understanding of the relationship between structure, properties and property dispersion is essential. In this paper we used electronic structure computer simulations to model the thermodynamic, mechanical and electronic properties of trigonal graphene nanoflakes with acute (highly reactive) corners. We find that these acute corners introduce new features that are different to the obtuse corners characteristic of hexagonal graphene nanoflakes, as well as different electronic states in the vicinity of the Fermi level. The structure and properties are sensitive to size and functionalization, and may provide new insights into the engineering of graphene nanoflake components.     

Use of QEMSCAN® for the characterization of Ni-rich and Ni-poor goethite in laterite ores

Nickel laterites are mineralogically complex, yet increasingly important sources of nickel and cobalt. To be successfully exploited they require accurate characterization of the mineralogy, texture and grade. As spatially resolved mineralogical techniques, automated scanning electron microscopy-based analysis systems (such as QEMSCAN^®) offer significant advantages over traditional bulk compositional and mineralogical methods. This project tests how QEMSCAN^® can be employed to characterize goethite and potentially interfering mineral compounds in nickel laterites. This involves the development and testing of a Species Identification Protocol (SIP) that discriminates goethite on the basis of nickel, chromium, and manganese content. The SIP is calibrated to quantitative compositional data obtained by electron-probe microanalysis (EPMA). The SIP is tested on ore specimens from Çalda? (Turkey), Acoje (the Philippines) and Devolli (Albania). The project demonstrates the advantages of increased X-ray acquisition rate for the characterization of low-Ni concentrations and the significance of EPMA analysis for the quantitative validation of mineral identifications in the SIP.     

Reorientation in a Two-Dimensional Environment: I. Do Adults Encode the Featural and Geometric Properties of a Two-Dimensional Schematic of a Room?

Adults searched for a goal in images of a rectangular environment. The goal's position was constant relative to featural and geometric cues, but the absolute position changed across trials. Participants easily learned to use the featural cues to find the target, but learning to use only geometric information was difficult. Transformation tests revealed that participants used the color and shape of distinct features to encode the goal's position. When the features at the correct and geometrically equivalent corners were removed, participants could use distant features to locate the goal. Accuracy remained above chance when a single distant feature was present, but the feature farthest from the goal yielded lower accuracy than one closer. Participants trained with features spontaneously encoded the geometric information. However, this representation did not withstand orientation transformations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blood Urea Nitrogen Stability: A Feasibility Study for Home Hemodialysis Adequacy Testing Through Mail

Urea kinetic modeling measures the delivered dose of hemodialysis and is used to monitor dialysis adequacy. Obtaining samples for adequacy calculations is a challenge for home hemodialysis (HHD) patients. Ideally, the urea reduction ratio (URR) should be measured at a typical dialysis session; therefore, for HHD patients test specimens should be drawn at home and transferred to a clinical laboratory. Would blood urea nitrogen (BUN) remain stable if samples were mailed to the laboratory? To answer this question, BUN was measured in pre- and postdialysis samples from 20 patients over 8 days of laboratory storage. While BUN values varied among the patient population, neither pre- nor postdialysis values showed any significant variation during the 8-day storage time. These results suggest that BUN values are sufficiently stable for specimens to be drawn at home and mailed to a testing laboratory.     

User and developer common knowledge: Effect on the success of information system development projects

Since Information Systems Development (ISD) project success is difficult to achieve and the literature has shown the relationship between IS developer skills and system success is mixed, this paper isolates and studies the knowledge shared by users and developers and its interaction with group solving practices that may lead to ISD project success. We evaluate developer’s knowledge of application domains and user knowledge of IS development along with the level of group problem solving among users and developers as related to the ultimate success of the project. A survey of 168 ISD professionals indicates that a combination of both user knowledge of IS development and IS developer knowledge of application domains had significant impact on successful project outcomes. The magnitude of this success is moderated by the level of group problem solving activities held by the project implementation teams. Up to a certain point, the more group problem solving interaction the more successful the project outcome. However, if knowledge redundancy is very high then exchange of knowledge is not so essential.     

Reorienting in Images of a Three-Dimensional Environment.

Adult humans searched for a hidden goal in images depicting 3-dimensional rooms. Images contained either featural cues, geometric cues, or both, which could be used to determine the correct location of the goal. In Experiment 1, participants learned to use featural and geometric information equally well. However, men and women showed significant differences in their use of distant featural cues and the spontaneous encoding of geometric information when trained with features present. Transformation tests showed that participants could use either the color or the shape of the features independently to locate the goal. Experiment 2 showed that participants could use either configural or surface geometry when searching for the goal. However, their weighing of these geometric cues was dependent on initial training experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exercise as a treatment for hypertension in low-socioeconomic-status Black children.

Low-socioeconomic-status (SES) Black children have a higher mean blood pressure than most other groups. The antihypertensive effects of a 12-week aerobic exercise program were examined on 11 low-SES Black children, ages 8–12, who had blood pressure above the 95th percentile. A multiple baseline across three groups of children with baseline and exercise conditions was conducted. After the introduction of the exercise program, there were significant decreases in diastolic and systolic blood pressure. Cardiovascular fitness improved concurrently. The results suggest that vigorous exercise can decrease the blood pressure of low-SES hypertensive Black children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)