Endocrine disruption in brook trout (Salvelinus fontinalis) exposed to leachate from a public refuse dump

Lake Molnbyggen was previously found to harbour a large number of sexually immature female perch (Perca fluviatilis) suffering from endocrine disruption. In an attempt to pin-point the source of the endocrine-disrupting substance(s) (EDSs), brook trout (Salvelinus fontinalis) from Vadb?cken, a stream contaminated by leachate from a public refuse dump and which empties into Lake Molnbyggen, were investigated. In addition, female perch from Lakes Yxen and Kvarntj?rn, located up-stream and down-stream of Lake Molnbyggen, were investigated. Only 16.7% of the adult female brook trout in Vadb?cken were sexually mature, associated with decreased gonadosomatic index, lower brain aromatase activity, and lower circulating levels of testosterone and 17beta-oestradiol, in comparison to female brook trout from the reference stream Bj?rntj?rnsb?cken. Male brook trout showed decreased gonadosomatic index, in addition to bile duct hyperplasia in the liver, which was also found in female brook trout livers from Vadb?cken. In Lake Molnbyggen, 57.6% of the female perch were found to be sexually immature with high frequencies of skin lesions, such as sores and fin erosion, significantly decreased gonadosomatic index, lower aromatase activity, and lower levels of testosterone and 17beta-oestradiol. No signs of reproductive disorders or endocrine disruption were seen in female perch from Lakes Yxen and Kvarntj?rn compared to female perch from the reference lake, Lake Djursj?n. Since brook trout of both sexes from Vadb?cken displayed the same kind of serious adverse impairment of gonad development and endocrine disruption as perch from Lake Molnbyggen, very strong evidence are provided that the refuse dump is the source for the responsible EDS(s), since both Vadb?cken and Lake Molnbyggen are known to be contaminated by leachate from that dump. The low levels of PAHs and PCBs in the surface sediments of Lake Molnbyggen suggest that these pollutants are not the responsible EDS(s).     

Dredging associated effects: maternally transferred pollutants and DNA adducts in feral fish

This study reports on the bioavailability, maternal transfer, and genotoxicity in feral fish of organic sediment pollutants. Northern pike (Esox lucius) and perch (Perca fluviatilis) were caught in a polluted bay before and during dredging activities and from reference areas. Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were analyzed in ovulating eggs to investigate if the bay sediment posed a threat to early life-stages of fish. On the basis of previous investigations in this area, the level of exposure via maternal transfer and diffusive uptake of water-borne pollutants after hatch is likely sufficient to cause abnormalities in early life-stages of fish. During dredging, hepatic DNA adducts were elevated in adult fish, demonstrating an increased release of genotoxic compounds, which may contribute to adverse effects in aquatic organisms for several years. Although no substantial increase of maternally transferred pollutants were observed during dredging, this is the first time a correlation between hepatic DNA adducts in fish and pollutant burden in their eggs is demonstrated. Our findings underline the importance of combining chemical and toxicological methods as well as a need for greater emphasis on other polycyclic aromatic compounds in environmental risk evaluations.     

The effects of source resolution on resolution enhancement through shifted superimposition projection

Resolution in a projected display is traditionally defined by the number of pixels in the projector's spatial light modulator (SLM). In recent years, different techniques that increase the resolution on the screen above the number of SLM pixels have gained popularity. In one such technique, called pixel‐shifting or shifted‐superimposition, the display physically shifts every n^th frame on the projected screen, and the overlapping pixel grids forms a finer subpixel grid with a higher pixel count. There is still an open question how much this method increases the resolution and how to quantify it. The resolution on the screen also depends upon the resolution of the input image fed to the projector. In this work, we experimentally investigate how the projector performs with resolution enhancement through pixel‐shifting and how this method relates to the source resolution. We also investigate some known methods of resolution measurement and evaluate how these methods perform for the shifted‐superimposition case. We find that the resolution enhancement through shifted‐superimposition enhances the resolution to about 40% over native resolution, and we also find two different measurement methods (grille contrast and least resolvable line pair method) that is relevant for effectively measuring resolution within such systems.     

Metso化学制浆新技术非木材制浆方法

非本材制浆方法 本刊今年前两期介绍了Metso公司开发的先进的木材制浆技术,Metso在非木材制浆工艺与设备方面亦有独到之处……     

Vesicoureteral reflux in children: a phantom study of microwave heating and radiometric thermometry of pediatric bladder

We have investigated the use of microwave heating and radiometry to safely heat urine inside a pediatric bladder. The medical application for this research is to create a safe and reliable method to detect vesicoureteral reflux, a pediatric disorder, where urine flow is reversed and flows from the bladder back up into the kidney. Using fat and muscle tissue models, we have performed both experimental and numerical simulations of a pediatric bladder model using planar dual concentric conductor microstrip antennas at 915 MHz for microwave heating. A planar elliptical antenna connected to a 500 MHz bandwidth microwave radiometer centered at 3.5 GHz was used for noninvasive temperature measurement inside tissue. Temperatures were measured in the phantom models at points during the experiment with implanted fiberoptic sensors, and 2-D distributions in cut planes at depth in the phantom with an infrared camera at the end of the experiment. Cycling between 20 s with 20 Watts power for heating, and 10?s without power to allow for undisturbed microwave radiometry measurements, the experimental results show that the target tissue temperature inside the phantom increases fast and that the radiometer provides useful measurements of spatially averaged temperature of the illuminated volume. The presented numerical and experimental results show excellent concordance, which confirms that the proposed system for microwave heating and radiometry is applicable for safe and reliable heating of pediatric bladder.     

Composition and Refinement of Specifications of Parameterized Data Types

In [5] we introduced a framework for specification of parameterized data types utilizing a generalization of the traditional semantics based on the pushout construction. In the present paper, we address the issue of program development using this framework with particular emphasis on the notion of refinement. Unlike for the loose specifications, refinement does not amount merely to a narrowing of the model class, but primarily to introduction of additional structure into the specified program. We give examples based on the analogues of the classical vertical and horizontal composition of such specifications.     

Prediction of Pressure Drop at the Entry Section from Top Discharge Blow Tank in a Pneumatic Conveying System

Although some literature can be found on the behavior of blow tanks, very few studies could be found on the pressure loss at the entry section to a pipeline (henceforth called entry pressure loss) from a top discharge blow tank in a pneumatic conveying system, even though its magnitude can be significant as compared to the total system pressure drop. This article presents the results of an experimental study carried out to assess this entry pressure loss. The results indicate that it is possible to scale up the entry pressure loss based on laboratory-scale tests with a reasonable degree of accuracy.     

Project management education in Sweden

A postgraduate programme in project management has been implemented at Chalmers University of Technology in Göteborg, Sweden and this paper addresses the structure, educational objectives and future plans surrounding the course. It is shown how a programme that is intended to foster a deeper understanding of the project management field has to be built on a firm theoretical foundation, with an essential ingredient being the utilization of professional experience.