Dealing with multiple documents on the WWW: The role of metacognition in the formation of documents models

Drawing on the theory of documents representation (Perfetti et al., Toward a theory of documents representation. In: H. v. Oostendorp & S. R. Goldman (Eds.), The construction of mental representations during reading. Mahwah, NJ: Erlbaum, 1999), we argue that successfully dealing with multiple documents on the World Wide Web requires readers to form documents models; that is, to form a representation of contents and sources. We present a study in which we tested the assumption that the use of metacognitive strategies is crucial to the formation of documents models. A total of 100 participants with little medical knowledge were asked to conduct an Internet research on a medical topic. Participants were randomly assigned to four experimental groups that received different types of metacognitive prompts: participants either received evaluation prompts, monitoring prompts, both types of prompts, or no prompts. A control group took paper-and-pencil notes. Results showed that laypersons receiving evaluation prompts outperformed controls in terms of knowledge about sources and produced more arguments relating to the source of information when justifying credibility judgments. However, laypersons receiving evaluation prompts were not better able to indicate the source of information after Internet research than controls. In addition, laypersons receiving monitoring prompts acquired significantly more knowledge about facts, and performed slightly better on a comprehension test. It is concluded that the results underline the importance of metacognition in dealing with multiple documents.     

Influence of scattering layers on efficiency of dye-sensitized solar cells

Thin titaniumdioxide (TiO₂) semiconductor layer with different scattering layers was investigated in dye-sensitized solar cells (DSSC). Since the cost of the photoactive dye in the DSSC is relatively high, it is reasonable to assume that the price of the dye could be one of the decisive factors in determining the price of the DSSC modules. Use of a thin layer of nanocrystalline TiO₂ would imply reduction in the amount of dye coverage, however, lower amount of dye in the thin films would imply fewer electron generation upon illumination. Thus, it becomes necessary to include a light scattering layer such that the lower photon conversion due to thin layer could be compensated. In the present study up to 80% increase in current density was observed due to inclusion of scattering layers. Reflectance and transmittance measurements were employed in order to study the optical properties of these scattering layers. The scattering layers, which are considered here, are TiO₂-Rutile, zirconiumdioxide (ZrO₂), and layers consisting of these two in various proportions. With a 4 μm thin titanium dioxide semiconductor layer as photo electrode and an additional light scattering layer (consisting of TiO₂-Rutile and ZrO₂ in a ratio of 1:3), efficiencies of 6.8% were achieved.     

MPTP lesion causes neuroinflammation and deficits in object recognition in Wistar rats.

Animal models of Parkinson’s disease with dementia would greatly facilitate research into the underlying causes of this disorder. Here, we showed that bilateral infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into the substantia nigra pars compacta (SNc) of Wistar rats caused degeneration of nigrostriatal dopaminergic neurons, cell loss in the hippocampal CA1 area, as well as microglial activation and increase of interleukin-2 levels in several brain regions. In addition, increase of anxiety-like behavior and impairment of object recognition were observed in the MPTP-lesioned rats. These findings suggest that neuroinflammation may contribute to MPTP-induced neurodegeneration and behavioral deficits, which is suggested as an animal model of Parkinson’s disease dementia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accumulation of storage lipids in species of Rhodococcus and Nocardia and effect of inhibitors and polyethylene glycol

Members of the genera Rhodococcus and Nocardia corallina were investigated for their capability to accumulate storage lipids that occur in the cytoplasm during cultivation of the cells under nitrogen-limiting conditions in the absence or presence of various effectors. All bacteria were able to accumulate triacylglycerols (TAG) as main compounds plus minor amounts of diacylglycerols and wax esters. In addition to neutral lipids, R. fascians, R. erythropolis, and R. opacus MR22 accumulated small amounts of polyhydroxybutyrate (PHB), and N. corallina and R. ruber accumulated significant amounts of polyhydroxyalkanoates (PHA) consisting of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) from glucose or valerate. Alloxan or 3-nitropropionate, which are inhibitors of the citric acid cycle, caused a decrease in the content of odd-numbered fatty acids in the TAG accumulated from acetate by R. opacus PD630. Cerulenin, an inhibitor of the fatty acid de novo synthesis, completely inhibited accumulation of TAG from glucose or gluconate but not from hexadecane in all bacteria investigated. In addition, cerulenin caused an increase of the PHA content and resulted in an increase of the relative amounts of 3HB units in the PHA in R. ruber and N. corallina. Acrylic acid, an inhibitor of fatty acid β-oxidation, completely or partially inhibited accumulation of TAG from hexadecane or valerate, respectively, in R. opacus PD630. In R. ruber, acrylic acid completely inhibited accumulations of TAG from valerate; under these conditions the content of PHA increased twofold, and the polyester consisted exclusively of 3HV. PEG-200 (0.2 to 5%, w/v) caused a decrease in the PHA content, but stimulated the incorporation of 3HV units into the PHA in R. ruber. Therefore, the relative amounts and compositions of both storage lipids can be affected by various compounds in these Gram-positive bacteria.     

A contrast- and brightness-insensitive optoelectronic edge detector

A specialized photodetector structure for optical edge detection and its CMOS-compatible realization are presented. It can detect a single edge with a relative motion to the detector. Because of point symmetry, the edge may be detected regardless of its orientation. Influences of contrast and brightness variations at an edge can be eliminated by subtracting the photocurrents of two photodiodes arranged in a circle/ring structure. The detectors are fabricated in CMOS technology and have been successfully tested.     

Therapeutic results with Cerebrolysin in the treatment of dementia

BACKGROUND: In the present study patients suffering from dementia were treated with an infusion therapy using the neurotrophic drug Cerebrolysin. The effectiveness of the therapy was examined under conditions of daily clinical practice. METHODS: 645 Patients were treated with 30 ml Cerebrolysin daily. The average period of treatment was 17.8 days. Prior to treatment patients were diagnosed according to DSM-III-R. In addition a differential diagnostic examination using the Hachinski Ischemic Score was performed. Clinical symptoms and the Clinical Global Impression (CGI) were determined before and after therapy. RESULTS: Cerebrolysin therapy led to a significant (p < 0.001) improvement in memory for 62% of the patients. 65% showed improvement in concentration, 50% in mood and fatigue, and 47% improved in vertigo. An improvement in the Clinical Global impression was observed in approximately 80% of the patients. The improvement of symptoms was significantly larger (p < 0.05) in younger, less afflicted patients than in the older, more seriously ill patients. The unusual good tolerance of Cerebrolysin was especially noteworthy. CONCLUSIONS: The present study confirms the results of earlier clinical studies with Cerebrolysin in the treatment of Alzheimer patients and patients with vascular dementia in which similar responder rates were observed. The significant dependence of therapeutic success on the length and severity of illness confirms that timely pharmacological intervention leads to best therapeutic results.     

Solid media thermal storage for parabolic trough power plants

For parabolic trough power plants using synthetic oil as the heat transfer medium, the application of solid media sensible heat storage is an attractive option regarding investment and maintenance costs. In the project WESPE that is described in this paper, solid media sensible heat storage materials have been researched. Two storage systems with a storage capacity of about 350 kW h each and maximum temperatures of 390 °C have been developed. The test storage units of WESPE are erected at the Plataforma Solar de Almeria in Spain. The thermal energy is provided by a parabolic trough loop with a maximum thermal power of 480 kW. The first tests were performed at storage temperatures up to 325 °C by March of 2004; testing will be continued during 2004 to achieve the nominal operation conditions of 390 °C and to gain experience for long term behaviour. These storage systems are composed of modules with two different storage materials to identify the characteristics of these materials. A tubular heat exchanger is integrated into the storage material. This heat exchanger demands a significant share of the investment costs. The selection of geometry parameters like tube diameter and number of tubes therefore play an important role in the optimisation. The design of the WESPE test module is based on results provided by a numerical tool for simulation of the transient performance of storage systems.