Levels of hopelessness in children and adolescents: A developmental perspective.

We investigated hopelessness at 3 age levels (8-, 12-, and 17-year-olds) in 210 children and adolescents from a community sample derived from public school listings of 4,810 children in a midwestern college town. The sample included 105 boys and 105 girls, and there were 70 subjects in each age group. The major finding was that children with high hopelessness scores are at greater risk not only for suicide and depression as revealed by the Child Assessment Schedule and the Birleson Depression Scale but also for overall psychopathology. This study suggests that hopelessness does not increase from preadolescence to adolescence in a general population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

KINETICS OF THE CLAY ROOFING TILE CONVECTION DRYING

Kinetics of the convection drying process of flat tile has been investigated experimentally in an industrial tunnel dryer. Several velocities of wet tile movement through the dryer were tested to obtain maximum allowable drying rate curve. As there are various models to describe the kinetics of convection drying, finding a model that would fairly well approximate the kinetics of the whole drying process was part of the research. Especially the polynomial and exponential models were tested.

It was found that exponential model of the type: B(t) = (a-B_e. EXP(-bt²) +B_et (-dB(t)/dt) = 2bt(B(t)-B_e significantly correlates the kinetics of the whole tile drying process.

Applying the maximum allowable drying rate curve obtained for flat tile in the first period of drying, a grapho-analytic model for the optimal conducting of the process has been developed.     

Artificial neural networks for flexible manufacturing systems scheduling

Artificial neural networks (ANNs) are information processing systems motivated by the goals of reproducing the cognitive processes and organizational models of neurobiological systems. By virtue of their computational structure, ANN's feature attractive characteristics such as graceful degradation, robust recall with noisy and fragmented data, parallel distributed processing, generalization to patterns outside of the training set, nonlinear modeling capabilities, and learning. These computational features could provide enhanced inferencing functionality and real-time capabilities to develop approaches for traditional difficult problems such as flexible manufacturing system (FMS) scheduling. In this paper three different schemes of ANN's are applied to the FMS scheduling problem. These include a) relaxation-based networks, b) competitive-based schemes, and c) adaptive pattern recognition scheduling.     

Automatic assembly path planning for wiring harness installations

The automotive industry of today is becoming more focused on electrified and hybrid solutions, where both conventional combustion engines and battery supplied electrical engines need to fit in an already densely packed vehicle. Many quality problems are related do flexible parts. In particular, the assembly of electric cables and wiring harnesses is difficult due to its concealed routing, multiple branching points, weights and the flexibility in the material. To avoid late detection of assembly problems, the assembly aspect must be considered early during conceptual design and production preparation with respect to both feasibility and ergonomics. Development of automatic path planning methods in virtual manufacturing tools supporting deformable parts is therefore highly motivated.     

Changes in in vivo metabolism of bile acids in rat after treatment with phenobarbital

The influence of phenobarbital on pool size and turnover of bile acids in rats have been investigated by administration of [24-¹⁴C] cholic acid and tritium labeled chenodeoxycholic acid. Phenobarbital treated rats had a smaller cholic acid pool compared to control rats (6.08±2.09 mg and 23.60±7.66 mg, respectively). The pool size of chenodeoxycholic acid, plus its metabolites (α- and β-muricholic acids), was of the same magnitude in the two groups of animals. Also the daily production of cholic acid was decreased in phenobarbital treated rats compared to control rats (2.12±0.46 mg and 7.24±1.66 mg, respectively). No significant difference was observed between the synthesis of chenodeoxycholic acid in the two groups of animals.     

Investigation of viruses in Diporeia spp. from the Laurentian Great Lakes and Owasco Lake as potential stressors of declining populations

The benthic amphipod Diporeia is an ecologically and biogeochemically important constituent of deep freshwater lakes in North America. The proliferation of dreissenid mussels in the mid-1990s coincided with a sharp decrease in Diporeia populations in several Laurentian Great Lakes; however the ultimate cause and mechanisms of their decline are still unknown. Here we examined the composition of DNA viruses associated with Diporeia collected from populations of Lake Michigan that had declined and stable populations in Lake Superior and Owasco Lake (Finger Lake in central New York State). Viral metagenomic libraries from Owasco Lake and Lake Superior were comprised primarily of bacteriophages, which may infect bacteria within the amphipod microbiome. In contrast, the metagenomic library from Lake Michigan contained well-represented ssDNA circular viral genomes. The prevalence and viral load of one putative Type V ssDNA circular virus (LM29173) that recruited almost 30% of total viral sequence reads in the Lake Michigan library was analyzed by quantitative PCR. The prevalence of LM29173 was over two orders of magnitude greater in Lake Michigan compared to the other two lakes. Although further research is necessary to establish the pathology and epidemiological extent of viral-Diporeia interactions, our data suggest that viruses may be numerically significant constituents of the Diporeia microbiome, and if pathogenic some of these viruses may be a stressor of Great Lakes Diporeia populations. Our data further indicate that special attention should be given to the circovirus that was prevalent in the declining Michigan population but uncommon in the other two lakes.     

Tribochemical Formation of Sulphide Tribofilms from a Ti–C–S Coating Sliding Against Different Counter Surfaces

Tribochemically active Ti–C–S coatings are nanocomposite coatings containing a S-doped titanium carbide, from which S can be released in a tribological contact. This work studies tribochemical reactions between a Ti–C–S coating and various counter surface materials, and their effect on the tribological performance. Tribological tests were performed in a ball-on-disc set-up, using balls of five different materials as sliding partners for the coating: 100Cr6 steel, pure W, WC, 316-L steel and Al₂O₃. For W balls, a WS₂ tribofilm was formed, leading to low friction (down to µ = 0.06). Furthermore, increasing normal load on the W balls was found to lead to a strong decrease in µ and earlier formation of the low-friction WS₂ tribofilm. Similar WS₂ and MoS₂ tribofilms were, however, not formed from WC- and Mo-containing 316-L balls. The performance when using WC and Al₂O₃ balls was significantly worse than for the two steel balls. It is suggested that this is due to sulphide formation from Fe, analogous to formation of anti-seizure tribofilms from S-containing extreme pressure additives and steel surfaces. The tribochemical activity of Ti–C–S coatings, with the possibility of S release, is thus beneficial not only for pure W counter surfaces, but also for Fe-based sliding partners.     

Efficient Depth of Field Rasterization Using a Tile Test Based on Half‐Space Culling

For depth of field (DOF) rasterization, it is often desired to have an efficient tile versus triangle test, which can conservatively compute which samples on the lens that need to execute the sample‐in‐triangle test. We present a novel test for this, which is optimal in the sense that the region on the lens cannot be further reduced. Our test is based on removing half‐space regions of the (u, v) ‐space on the lens, from where the triangle definitely cannot be seen through a tile of pixels. We find the intersection of all such regions exactly, and the resulting region can be used to reduce the number of sample‐in‐triangle tests that need to be performed. Our main contribution is that the theory we develop provides a limit for how efficient a practical tile versus defocused triangle test ever can become. To verify our work, we also develop a conceptual implementation for DOF rasterization based on our new theory. We show that the number of arithmetic operations involved in the rasterization process can be reduced. More importantly, with a tile test, multi‐sampling anti‐aliasing can be used which may reduce shader executions and the related memory bandwidth usage substantially. In general, this can be translated to a performance increase and/or power savings.     

The acceptance of Moodle technology by business administration students

The advent of information technologies to Universities has improved the teaching-learning process. Students can increase their learning skills using information technology. Those using the Moodle platform regularly seem to get better grades than those who rarely or never use it.This paper analyzes students’ intention to use Moodle platforms to improve the teaching-learning process. Its main focus is to analyze the use of the Moodle platform by University students, identifying factors which might influence the intention to use it. Understanding the factors influencing the intention to use Moodle will allow us to determine which actions might be carried out to boost its use by University students, to therefore, improve both their skills and grades.The theoretical grounding for this research is the Technology Acceptance Model (TAM). TAM specifies the causal relationships between perceived usefulness, perceived ease of use and actual usage behavior. The proposed model has six constructs and nine hypotheses have been generated from the connections between these six constructs. These constructs include perceived compatibility with student tasks, perceived usefulness for professors, and training. Our results provide support for a number of relationships in the hypothesized model. In light of these findings, implications for theory and practice are discussed.     

Effect of xylose and nutrients concentration on ethanol production by a newly isolated extreme thermophilic bacterium

An extreme thermophilic ethanol-producing strain was isolated from an ethanol high-yielding mixed culture, originally isolated from a hydrogen producing reactor operated at 70 degrees C. Ethanol yields were assessed with increasing concentrations of xylose, up to 20 g/l. The ability of the strain to grow without nutrient addition (yeast extract, peptone and vitamins) was also assessed. The maximum ethanol yield achieved was 1.28 mol ethanol/mol xylose consumed (77% of the theoretical yield), at 2 g/l of initial xylose concentration. The isolate was able to grow and produce ethanol as the main fermentation product under most of the conditions tested, including in media lacking vitamins, peptone and yeast extract. The results indicate that this new organism is a promising candidate for the development of a second generation bio-ethanol production process.