Navigation in hypermedia learning systems: Experts vs. novices

With the advancement of Web technology, hypermedia learning systems are becoming more widespread in educational settings. Hypermedia learning systems present course content with non-sequential formats, so students are required to develop learning paths by themselves. Yet, empirical evidence indicates that not all students can benefit from hypermedia learning. Research into individual differences suggests that prior knowledge has significant effects on student learning in hypermedia systems, with experts and novices showing different preferences to the use of hypermedia learning systems and requiring different levels of navigation support. It is therefore essential to develop a mechanism to help designers understand the needs of experts and novices. To address this issue, this paper presents a framework to illustrate the needs of students with different levels of prior knowledge by analyzing the findings of previous research. The overall aim of this framework is to integrate students’ prior knowledge into the design of hypermedia learning systems. Finally, implications for the design of hypermedia learning systems are discussed

Developments in electrochemical processes for recycling lead-acid batteries

The lead-acid battery recycling industry is very well established, but the conventional pyrometallurgical processes are far from environmentally benign. Hence, recent developments of lead-acid battery recycling technologies have focused on low-temperature (electro-)hydrometallurgical processes, the subject of this review, covering modified electrolytes, improved reaction engineering, better reactor design and control of operating conditions

Significance of Pyuria in the Diagnosis of Urinary Tract Infection in Children with Sickle Cell Anaemia in Maiduguri, Nigeria

Urinary tract infection (UTI) is a significant cause of morbidity and mortality in children, especially in those with sickle cell disease, who are at higher risk of infections. It will be useful to have a simple test which can be used in resource limited health facilities as a means of screening such children for UTI with the view to instituting prompt treatment. This study is carried out to determine the usefulness of significant pyuria in detecting UTI in febrile children with sickle cell anaemia (SCA). Two hundred and fifty febrile children with sickle cell anaemia that attended State Specialist Hospital and University of Maiduguri Teaching Hospital (UMTH) were prospectively studied with their consent. Urine sample was collected using standard procedure, examined for pus cells and was cultured at the Microbiology laboratory of UMTH. The study showed UTI prevalence of 26%. Significant pyuria was found to have sensitivity of 55.4%, specificity of 77.8%, the efficacy of the test was 72.0% and the test has low positive predictive value of 46.8% in detecting bacteriuria in SCA patients. The significant pyuria observed in this study support its usefulness in the diagnosis of UTI among children with SCA especially in communities having limited facilities or personnel for carrying out urine culture.Keywords: Sickle Cell Anaemia, Bacteriuria, Pyuri

Catatonic Episodes Related to Substance Use: A Cross-Sectional Study Using Electronic Healthcare Records

OBJECTIVE: Substance use has increasingly been linked to the onset of catatonic episodes; however, no large observational studies have examined this association. This study aimed to identify catatonic episodes temporally associated with acute intoxication, withdrawal or chronic substance use, investigate which substances were involved, and compare clinical characteristics of substance-related and non-substance-related catatonic episodes. METHODS: This study retrospectively identified all catatonic episodes recorded in an electronic case register hosted at a large secondary mental health trust in London, UK. Episodes were categorized as substance-related if the clinical record reported either a positive urine drug screen, an ICD-10 diagnosis of a mental or behavioral disorder due to substance use, or documented substance use between two weeks prior to the catatonic episode and the date of the catatonic episode. RESULTS: 108 of 2130 catatonic episodes (5.1%) were deemed substance-related. The number of contemporaneously reported substance-related episodes increased between 2007 and 2016 [r = 0.72, p = 0.02]. Episodes in the context of acute intoxication (n = 54) were most frequently related to cannabis (n = 31) or cocaine (n = 5) use, whilst those in the context of drug withdrawal (n = 8) were most commonly related to alcohol, opioids and benzodiazepines. There were 50 episodes of catatonia associated with chronic substance use without intoxication or withdrawal, of which the majority were related to cannabis use (n = 37). 21 episodes had overlapping intoxication, withdrawal and chronic use of different substances within an episode. Compared to catatonic episodes not related to substance use, episodes of substance-related catatonia occurred in individuals who were younger (mean age 31.3 years [SD 12.2] vs 35.7 years [SD 16.3], p = 0.01) and more likely to be men (74.0% vs 54.3%, p < 0.001). The clinical features of catatonia were similar between the two groups. CONCLUSIONS: A relatively small proportion of catatonic episodes were temporally associated with reported substance use within their electronic records. Substance-related catatonic episodes were mostly related to cannabis use, but other substances including cocaine, alcohol, opioids and benzodiazepines were sometimes implicated. This is likely an underestimate of substance-related catatonia use due to issues with documentation and appropriate investigation

Psychometric Properties of the Training Parenting Style Scale in a Malaysian Sample of Adolescents: Factor Analysis, Internal Consistency, and Measurement Invariance

The importance of parenting styles on children’s outcomes, including cognitive, social, academic, and values makes this topic a central concern to social researchers and psychologists. However, past research has reported controversial evidence on the relationship between authoritarian parenting and children’s outcomes in non-Western cultural contexts. This raises awareness on the implication of cultural differences in parenting styles. As a result, the training parenting style scale (TPSS) was proposed based on the Confucian concept of ‘Guan’ and ‘Chiao Shu.’ This scale is allegedly more reflective of the Asian parenting style. The present study examined the psychometric properties and measurement invariance of the Malay version of the TPSS across adolescents’ perceived maternal and paternal training and by adolescent gender. Of the 8 items in the original TPSS, confirmatory factor analysis supported 6-item scale with error correlations was the best-fitting model. Internal consistency was also good for the 6-item scale. Furthermore, support for configural, metric, scalar, residual, and structural invariance emerged across adolescents’ perceived maternal and paternal training and across adolescent gender. Results of this study supported the psychometric properties of the 6-item TPSS after taking into account several cautiously considered limitations

Tectonic affinity of the west Qinling terrane (central China): North China or Yangtze?

[33] Neogene (̃14 Ma) basaltic magmatism has occurred in west Qinling, at the northeastern corner of the Tibetan Plateau. Furthermore, U-Pb ages and Hf isotopic data of xenocrystic zircons indicate that the unexposed Neoarchean (2.7-2.5 Ga) basement beneath the Phanerozoic outcrops in west Qinling has affinities with the southern margin of the north China block. The basement has a complex evolution, including the addition of juvenile mantle material at ̃2.7- 2.4 Ga and 1.1-0.8 Ga and reworking at ̃1.8 Ga and possibly at 1.4 Ga. Phanerozoic thermal events at 320-300 Ma, 230 Ma, and 160 Ma also have affected the basement. We interpret the west Qinling orogenic terrane as originally separated from the north China block, joined to the northern Yangtze block during the Meso-Neoproterozoic, and finally involved in the northward subduction and collision of the Yangtze block in the Paleozoic and early Mesozoic and subsequent lithospheric extension in the Jurassic. © 2010 by the American Geophysical Union.published_or_final_versio

Vibration suppression for monopile and spar-buoy offshore wind turbines using the structure-immittance approach

Offshore wind turbines have the potential to capture the high-quality wind resource. However, the significant wind and wave excitations may result in excessive vibrations and decreased reliability. To reduce vibrations, passive structural control devices, such as the tuned mass damper (TMD), have been used. To further enhance the vibration suppression capability, inerter-based absorbers (IBAs) have been studied using the structure-based approach, that is, proposing specific stiffness-damping-inertance elements layouts for investigation. Such an approach has a critical limitation of being only able to cover specific IBA layouts, leaving numerous beneficial configurations not identified. This paper adopts the newly introduced structure-immittance approach, which is able to cover all network layout possibilities with a predetermined number of elements. Linear monopile and spar-buoy turbine models are first established for optimisation. Results show that the performance improvements can be up to 6.5% and 7.3% with four and six elements, respectively, compared with the TMD. Moreover, a complete set of beneficial IBA layouts with explicit element types and numbers have been obtained, which is essential for next-step real-life applications. In order to verify the effectiveness of the identified absorbers with OpenFAST, an approach has been established to integrate any IBA transfer functions. It has been shown that the performance benefits preserve under both the fatigue limit state (FLS) and the ultimate limit state (ULS). Furthermore, results show that the mass component of the optimum IBAs can be reduced by up to 25.1% (7,486 kg) to achieve the same performance as the TMD

The Sunyaev-Zeldovich Effect and Its Cosmological Significance

Comptonization of the cosmic microwave background (CMB) radiation by hot gas in clusters of galaxies - the Sunyaev-Zeldovich (S-Z) effect - is of great astrophysical and cosmological significance. In recent years observations of the effect have improved tremendously; high signal-to-noise images of the effect (at low microwave frequencies) can now be obtained by ground-based interferometric arrays. In the near future, high frequency measurements of the effect will be made with bolomateric arrays during long duration balloon flights. Towards the end of the decade the PLANCK satellite will extensive S-Z surveys over a wide frequency range. Along with the improved observational capabilities, the theoretical description of the effect and its more precise use as a probe have been considerably advanced. I review the current status of theoretical and observational work on the effect, and the main results from its use as a cosmological probe.Comment: Invited review; in proceedings of the Erice NATO/ASI `Astrophysical Sources of High Energy Particles and Radiation'; 11 pages, 3 figure

GdxSi grown with mass-analyzed low energy dual ion beam epitaxy technique

Semiconducting gadolinium silicide GdxSi samples were prepared by mass-analyzed low-energy dual ion beam epitaxy technique. Auger electron spectroscopy depth profiles indicate that the gadolinium ions are implanted into the single-crystal silicon substrate and formed 20 nm thick GdxSi film. X-ray double-crystal diffraction measurement shows that there is no new phase formed. The XPS spectra show that one type of silicon peaks whose binding energy is between that of silicide and silicon dioxide, and the gadolinium peak of binding energy is between that of metal Gd and Gd2O3. All of these results indicate that an amorphous semiconductor is formed. (C) 2002 Elsevier Science B.V. All rights reserved