A comparison of structured and unstructured navigation through a CBT package

The advent of hypertext has opened up new possibilities in computer-based training. The design of courseware without any predetermined structure could make the designer's task easier, and allow greater flexibility for the trainee to structure the learning environment to suit their own learning style, This investigation was concerned with the exploration of performance differences in structured and unstructured training environments. In the structured condition, subjects encountered presequenced training and practice modules. For the unstructured condition, subjects determined their own sequence of modules. It was proposed that performance may be better in the unstructured condition. The findings indicate that this depends upon individual differences in cognitive style, some styles seemingly better at exploiting the unstructured learning environment than others

Photoconductive power switches

This paper outlines the advantages and the potential of photoconductive switches applied to high-power systems. The photoconductive effect can be used to switch large amounts of energy by changing the conductivity of a solid-state circuit element many orders of magnitude with a high-power laser. The simplicity of these devices offers many advantages in high-power applications when combined with high-power pulsed lasers. The surge capability, the switched energy gain, and the maximum average power for photoconductive power switches are discussed. In addition, the results of a 100-kV, 100-MW photoconductive switch experiment transferring 20 J in 200 ns are presented

Photoconductor pulse generators and sampling gates for characterization of high-speed devices and transmission lines

We describe photoconductive semiconductor devices developed for application in diagnostics of high-speed electronic devices and circuits. Both pulse generation and sampling functions are provided by these ultrafast photoconductors. The photoresponse of different semiconductor materials (GaAs, InP, Si) that have been ion bombarded (Ar, H, He, Ne, O, Si) was investigated and characterized. Response times as short as 1 picosecond have been observed. High frequency propagation characteristics of microstrip and coplanar waveguide transmission lines have been studied and modelled. Application of this measurement technique to the characterization of a microwave GaAs transistor is presented

Piping elbow irrecoverable pressure loss coefficients for moderately high Reynolds numbers

Test data is described for three different piping elbows. These include 900 elbows with radii of curvature of 12 and 1.5, and a 45{degrees} elbow with a radius of curvature of 1.2. These radii of curvature are sufficiently sharp to cause significant irrecoverable pressure losses to occur. The variation in static wall pressure was measured upstream and downstream of each elbow plus spatially around the elbow itself. Irrecoverable loss coefficients over a range of flows were obtained and correlations for the data are provided. The testing extended the Reynolds number range of the currently existing data base in various handbooks (and other references available in the open literature) by over a factor of five. Comparisons of results to predictions from the correlations of prior studies are provided

Back in Time? A Temporal Autobiographical Approach to Afghan Return Migration

Repatriation programmes for refugees and asylum seekers are based on the assumption that going ‘home’ is the most desirable thing to do to restore the social order that was disrupted by conflict. Yet the often-limited success of these programmes as migration management solutions, shown in poor reintegration results and re-emigration, shows that there is a need for a better understanding of the lived experiences of (return) migrants. This article studies Afghan managed and “spontaneous” return migrants from Europe through an innovative temporal autobiographical approach, using both verbal and creative participatory narrative methods. I find that some migration movements were experienced as disruptive, while others were not, and that return sometimes meant a return to a previous life, sometimes a continuation, and sometimes the start of something new. I conclude that migration management programmes aimed towards “durable solutions” and the wellbeing of returnees should enable rather than constrain post-return mobility

Carbon clusters near the crossover to fullerene stability

The thermodynamic stability of structural isomers of $\mathrm{C}_{24}$, $\mathrm{C}_{26}$, $\mathrm{C}_{28}$ and $\mathrm{C}_{32}$, including fullerenes, is studied using density functional and quantum Monte Carlo methods. The energetic ordering of the different isomers depends sensitively on the treatment of electron correlation. Fixed-node diffusion quantum Monte Carlo calculations predict that a $\mathrm{C}_{24}$ isomer is the smallest stable graphitic fragment and that the smallest stable fullerenes are the $\mathrm{C}_{26}$ and $\mathrm{C}_{28}$ clusters with $\mathrm{C}_{2v}$ and $\mathrm{T}_{d}$ symmetry, respectively. These results support proposals that a $\mathrm{C}_{28}$ solid could be synthesized by cluster deposition.Comment: 4 pages, includes 4 figures. For additional graphics, online paper and related information see http://www.tcm.phy.cam.ac.uk/~prck

Gendering the careers of young professionals: some early findings from a longitudinal study. in Organizing/theorizing: developments in organization theory and practice

Wonders whether companies actually have employees best interests at heart across physical, mental and spiritual spheres. Posits that most organizations ignore their workforce – not even, in many cases, describing workers as assets! Describes many studies to back up this claim in theis work based on the 2002 Employment Research Unit Annual Conference, in Cardiff, Wales

New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk

Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes