The nature of ecstasy-group related deficits in associative learning

Rationale/objectives: Research has revealed associative learning deficits among users of ecstasy; the present study explored the component processes underlying these deficits. Methods: Thirty-five ecstasy users and 62 non-ecstasy users completed a computer-based, verbal paired-associates learning task. Participants attempted to learn eight sequentially presented word pairs. After all eight had been presented, the first member of each pair was displayed and participants attempted to recall the second. Eight trials were administered. Correct responses on each trial, forgetting at various levels of learning, perseveration errors and the rate at which the associations were learned (trials to completion) were all recorded. Results: MANOVA revealed that ecstasy users performed worse overall and subsequent ANOVAs showed that users performed significantly worse on virtually all measures. Regression analysis revealed that over half of the ecstasy-group related variance in trials to completion was attributable to group differences in initial learning and forgetting. In relation to forgetting, it appears that cannabis use may be an important determinant. In relation to rate of learning (trials to completion) and initial learning, both ecstasy and cannabis may be implicated. Conclusions: There appears to be abundant evidence of associative learning deficits among ecstasy users. However, it appears that a range of illicit drugs including cannabis and ecstasy may contribute to these deficits

Rapid solutions for application specific IGBT module design

The electric car, the all electric aircraft and requirements for renewable energy are prime examples of potential technologies needing to be addressed in the world problem of global warming/carbon emission etc. Power electronics are fundamental for the underpinning of these technologies and with the diverse requirements for electrical configurations and the range of environmental conditions, time to market is paramount for module manufacturers and systems designers alike. This paper presents a 'virtual' design methodology together with theoretical and experimental results that demonstrate enhanced product design with improved reliability, performance and cost value within competitive schemes

Learning across business sectors: knowledge sharing between aerospace and construction

This report addresses the extent that managerial practices can be shared between the aerospace and construction sectors. Current recipes for learning from other industries tend to be oversimplistic and often fail to recognise the embedded and contextual nature of managerial knowledge. Knowledge sharing between business sectors is best understood as an essential source of innovation. The process of comparison challenges assumptions and better equips managers to cope with future change. Comparisons between the aerospace and construction sectors are especially useful because they are so different. The two sectors differ hugely in terms of their institutional context, structure and technological intensity. The aerospace sector has experienced extensive consolidation and is dominated by a small number of global companies. Aerospace companies operate within complex networks of global interdependency such that collaborative working is a commercial imperative. In contrast, the construction sector remains highly fragmented and is characterised by a continued reliance on small firms. The vast majority of construction firms compete within localised markets that are too often characterised by opportunistic behaviour. Comparing construction to aerospace highlights the unique characteristics of both sectors and helps explain how managerial practices are mediated by context. Detailed comparisons between the two sectors are made in a range of areas and guidance is provided for the implementation of knowledge sharing strategies within and across organisations. The commonly accepted notion of ‘best practice’ is exposed as a myth. Indeed, universal models of best practice can be detrimental to performance by deflecting from the need to adapt continuously to changing circumstances. Competitiveness in the construction sector too often rests on efficiency in managing contracts, with a particular emphasis on the allocation of risk. Innovation in construction tends to be problem-driven and is rarely shared from project to project. In aerospace, the dominant model of competitiveness means that firms have little choice other than to invest in continuous innovation, despite difficult trading conditions. Research and development (R&D) expenditure in aerospace continues to rise as a percentage of turnovers. A sustained capacity for innovation within the aerospace sector depends crucially upon stability and continuity of work. In the construction sector, the emergence of the ‘hollowed-out’ firm has undermined the industry’s capacity for innovation. Integrated procurement contexts such as prime contracting in construction potentially provide a more supportive climate for an innovation-based model of competitiveness. However, investment in new ways of working depends upon a shift in thinking not only amongst construction contractors, but also amongst the industry’s major clients

Ultraviolet-Resistant Bacterial Spores

A document summarizes a study in which it was found that spores of the SAFR-032 strain of Bacillus pumilus can survive doses of ultraviolet (UV) radiation, radiation, and hydrogen peroxide in proportions much greater than those of other bacteria. The study was part of a continuing effort to understand the survivability of bacteria under harsh conditions and develop means of sterilizing spacecraft to prevent biocontamination of Mars that could interfere with the search for life there

Effects of pH_2O, pH_2 and fO_2 on the diffusion of h-bearing species in lunar basaltic liquid and an iron-free basaltic analog at 1 atm

We have experimentally determined the diffusivity of water in a representative lunar basaltic liquid composition (LG) and in an iron-free analog of a basaltic liquid (AD) at the low water concentrations and low oxygen fugacities (fO_2) relevant to the eruption of lunar basalts. Experiments were conducted at 1 atm and 1350 °C over a range of pH_2/pH_2O from near zero to ∼10 and a range in fO_2 spanning ∼9 orders of magnitude (from 2.2 log units below the iron-wüstite buffer, IW–2.2, to IW+6.7). The water concentrations measured in our quenched experimental glasses by secondary ion mass spectrometry (SIMS) and Fourier transform infrared spectroscopy (FTIR) vary from a few ppm to ∼430 ppm. Water concentration gradients in the majority of our AD experiments are well described by models in which the diffusivity of water (D*_(water)) has a constant value of ∼2×10^(–10) m^2/s, while our LG results indicate that D*_(water) in LG melt has a constant value of ∼6×10^(–10) m^2/s under the conditions of our experiments. Water concentration gradients in hydration and dehydration experiments that were run simultaneously in H_2/CO_2 gas mixtures are well described by the same D*_(water), and water concentrations measured near the melt-vapor interfaces of these experiment pairs are approximately the same. These observations strongly support an equilibrium boundary condition for our experiments containing >70 ppm H_2O. However, dehydration experiments into nominally anhydrous CO_2, N_2, and CO/CO_2 gas mixtures leave some scope for the importance of kinetics during dehydration of melts containing less than a few 10’s of ppm H_2O. Comparison of our results with the modified speciation model (Ni et al., 2013) in which both molecular water and hydroxyl are allowed to diffuse suggests that we have resolved the diffusivity of hydroxyl (D_(OH)) in AD and LG melts. Our results support a positive correlation between D_(OH) and melt depolymerization. Best-fit values of D*_(water) for our LG experiments vary within a factor of ∼2 over a range of pH_2/pH_2O from 0.007 to 9.7 and a range of logf O_2 from IW–2.2 to IW+4.9. The relative insensitivity of our best-fit values of D*_(water) to variations in pH_2 suggests that H_2 diffusion did not control the rate of degassing of H-bearing species from the lunar glasses of Saal et al. (2008); however, we cannot rule out a role for molecular H2 diffusion under lower-temperature and/or higher-pressure conditions than explored in our experiments. The value of D*_(water) chosen by Saal et al. (2008) for modeling the diffusive degassing of the lunar volcanic glasses is within a factor of ∼2 of our measured value in LG melt at 1350 °C. By coupling our LG results at 1350 °C with an activation energy of 220 kJ/mol (Zhang et al. 2017), we obtain the following Arrhenius relationship, which can be used to model syneruptive diffusive water loss from lunar melt beads: D*_(water)(m^2/s) = 7.2×10^(-3)exp(-2.6×10^4/T(K))

The biochemical role of the small G protein Rac1 in cell signalling pathways - Interaction with RhoGDI and the phagocyte NADPH oxidase component, p67phox

Rac is a small G protein with a number of signalling roles. Along with other members of the Rho family of small GTPases, it is involved in the control of the actin cytoskeleton (Hall, 1992) and an apparently separate role in the activation of the NADPH oxidase, an enzymatic mechanism in phagocytes which forms superoxide in response to bacterial infection. In an inactive state, Rho family proteins exist in a complex with a second cytosolic protein, Rho guanine nucleotide dissociation inhibitor, RhoGDI. Activation causes dissociation of the Rac GDI complex and movement of Rac to the membrane. Spectroscopic studies have been used to investigate the interaction of Racl with other molecules, such as p67phox, a component of the NADPH oxidase complex. Complexes of racl with 2'(3')O-(N-methylanthraniloyl) (mant) fluorescent nucleotide analogues (eg. mantGDP) have been used to try to develop methods to study the interaction of Racl and p67phox. Although a previous report indicates a fluorescent change when Racl (complexed to a fluorescent nucleotide analogue) is incubated with p67phox, these experiments could not be repeated. A number of other approaches have been taken to develop a system to monitor the interaction of Rac and p67phox. Fluorescent approaches have also been developed to study the interaction of Rac and RhoGDI. GDI has previously been labelled with the fluorophore N-[2-1-(maleimidyl)ethyl]-7- (diethylamino)coumarin-3-carboxamide (MDCC) on a single cysteine in our laboratory and shows a large fluorescence decrease on Rac binding. Rac requires a lipid modification at the C-terminus to interact with RhoGDI, which presents a number of experimental difficulties. A system has been developed using C-terminally truncated (E.coli expressed) Rac and a farnesylated C-terminal peptide that mimics full length Racl that has been lipid modified in vivo (Newcombe et al., 1999). We are currently using this system to study the interaction of Racl with GDI and a number Racl point mutants have been made in the major regions of divergence between Ras superfamily proteins, based on the crystal structure of Racl (Hirshberg et al., 1997). In addition, a Racl/H-Ras chimaeric protein has been made and expressed in this laboratory. Results indicate that a region of the Racl effector loop is important for the Racl GDI interaction, with mutations in the insertion loop of Racl having little or no affect on the affinity of the Racl GDI interaction (Newcombe, Hunter & Webb, unpublished results). In addition, the interaction of Racl with a number of novel fluorescent nucleotide analogues including 3'-O-[N-[2-(7-diethylaminocoumarin-3-carboxamido)ethyl]carbamoyl] GTP (cou-edaGTP) and coumarin343-edaGTP (but-edaGTP) have been tested, and Racl complexes have shown that the rate of nucleotide hydrolysis and exchange by Racl shows them to be good analogues of GTP. It is hoped that these analogues will be useful to study the interaction of Racl with other proteins, such as GDI and p67phox

Performance of Small Cluster Surveys and the Clustered LQAS Design to estimate Local-level Vaccination Coverage in Mali

<p>Abstract</p> <p>Background</p> <p>Estimation of vaccination coverage at the local level is essential to identify communities that may require additional support. Cluster surveys can be used in resource-poor settings, when population figures are inaccurate. To be feasible, cluster samples need to be small, without losing robustness of results. The clustered LQAS (CLQAS) approach has been proposed as an alternative, as smaller sample sizes are required.</p> <p>Methods</p> <p>We explored (i) the efficiency of cluster surveys of decreasing sample size through bootstrapping analysis and (ii) the performance of CLQAS under three alternative sampling plans to classify local VC, using data from a survey carried out in Mali after mass vaccination against meningococcal meningitis group A.</p> <p>Results</p> <p>VC estimates provided by a 10 × 15 cluster survey design were reasonably robust. We used them to classify health areas in three categories and guide mop-up activities: i) health areas not requiring supplemental activities; ii) health areas requiring additional vaccination; iii) health areas requiring further evaluation. As sample size decreased (from 10 × 15 to 10 × 3), standard error of VC and ICC estimates were increasingly unstable. Results of CLQAS simulations were not accurate for most health areas, with an overall risk of misclassification greater than 0.25 in one health area out of three. It was greater than 0.50 in one health area out of two under two of the three sampling plans.</p> <p>Conclusions</p> <p>Small sample cluster surveys (10 × 15) are acceptably robust for classification of VC at local level. We do not recommend the CLQAS method as currently formulated for evaluating vaccination programmes.</p

Phenotypic microarrays suggest Escherichia coli ST131 is not a metabolically distinct lineage of extra-intestinal pathogenic E. coli

Extraintestinal pathogenic E. coli (ExPEC) are the major aetiological agent of urinary tract infections (UTIs) in humans. The emergence of the CTX-M producing clone E. coli ST131 represents a major challenge to public health worldwide. A recent study on the metabolic potential of E. coli isolates demonstrated an association between the E. coli ST131 clone and enhanced utilisation of a panel of metabolic substrates. The studies presented here investigated the metabolic potential of ST131 and other major ExPEC ST isolates using 120 API test reagents and found that ST131 isolates demonstrated a lower metabolic activity for 5 of 120 biochemical tests in comparison to non-ST131 ExPEC isolates. Furthermore, comparative phenotypic microarray analysis showed a lack of specific metabolic profile for ST131 isolates countering the suggestion that these bacteria are metabolically fitter and therefore more successful human pathogens

Proving Determinacy of the PharOS Real-Time Operating System

International audienceExecutions in the PharOS real-time system are deterministic in the sense that the sequence of local states for every process is independent of the order in which processes are scheduled. The essential ingredient for achieving this property is that a temporal window of execution is associated with every instruction. Messages become visible to receiving processes only after the time window of the sending message has elapsed. We present a high-level model of PharOS in TLA+ and formally state and prove determinacy using the TLA+ Proof System

3D modeling and motion parallax for improved videoconferencing

We consider a face-to-face videoconferencing system that uses a Kinect camera at each end of the link for 3D modeling and an ordinary 2D display for output. The Kinect camera allows a 3D model of each participant to be transmitted; the (assumed static) background is sent separately. Furthermore, the Kinect tracks the receiver’s head, allowing our system to render a view of the sender depending on the receiver’s viewpoint. The resulting motion parallax gives the receivers a strong impression of 3D viewing as they move, yet the system only needs an ordinary 2D display. This is cheaper than a full 3D system, and avoids disadvantages such as the need to wear shutter glasses, VR headsets, or to sit in a particular position required by an autostereo display. Perceptual studies show that users experience a greater sensation of depth with our system compared to a typical 2D videoconferencing system