An Evaluation of New Scottish Chemistry Syllabuses

During the early 1960's new syllabuses in Chemistry were intro-:duced into Scottish schools. A research programme was begun to evaluate these new syllabuses by comparing the performance and attitudes of university students reared on the old and new systems. Differences were found in favour of the new syllabus students. Initially, as a subsidiary part of this investigation, a study was made of the syllabus areas which the students reported to be difficult. On analysis, these difficulties fell into two well defined groups (a) topics associated with formulae, equations and the mole, and, (b) organic topics related to hydrolysis and condensation reactions. To trace the source of these problems the investigation moved into schools at 'O' grade, 'H' grade and Sixth Year Studies levels. The same problem areas became evident at all of these levels and as far down as Third Form. Almost all of the calculations were based on the operation of simple proportion, a skill which was taught in primary school. The difficulties with organic were all related to spatial arrangements of molecular models and their corresponding representations as formulae. Remedies were sought in terms of syllabus rearrangements and changes in method and these investigations ore continuing. A close examination of the problems in the light of the developmental work of Piamet has shorn that they are almost certainly linked with maturity barriers. The operation of simple proportion introduced at primary school well before the child has reached the necessary level of maturity (approx. 13) may well be at the root of the trouble with calculations. When this was then brought into contact with the multivariate thinking involved in writing chemical formulae, it was not surprising that problems occurred. When the investigation was being carried out at Sixth Year Studies level the opportunity was taken to gather the views of both students and teachers as to how well the course was fulfilling the objectives around which it was designed. The findings, on the whole, were very favourable towards the syllabus. The work embodied in this entire investigation is now actively being used by the Consultative Committee on the Curriculum in its planning of the "second generation" of new syllabuses

Semiconductor optical amplifiers in avionics

RSOAs have been demonstrated to operate within a WDM PON architectures over a >;60nm wavelength range with large path loss capabilities. Two RSOAs enable contiguous operation over the S, C and L bands; results indicate clearly that WDM architectures suitable for avionics with a PLC of >;25dB are possible with only two devices. Performance at extended temperature ranges will be reported later in detai

Wedge and Bridge: A Note on the Rhetoric of Distinction and Identification

Henry Johnstone (1970 p. 124, 1990) has advanced the slogan Rhetoric is a wedge to suggest the ways in which rhetoric calls attention to hitherto unnoticed consequences or assumptions, or even to features of the physical world that have escaped an audience\u27s attention. Here, however, we intend to supplement the notion of rhetoric as wedge by suggesting the ways in which it is, and also must be, a bridge

Calcite saturation, foraminiferal test mass, and Mg/Ca-based temperatures dissolution corrected using XDX—A 150 ka record from the western Indian Ocean

A record of deep-sea calcite saturation inline image, derived from X-ray computed tomography-based foraminifer dissolution index, XDX, was constructed for the past 150 ka for a core from the deep (4157 m) tropical western Indian Ocean. G. sacculifer and N. dutertrei recorded a similar dissolution history, consistent with the process of calcite compensation. Peaks in calcite saturation (∼15 µmol/kg higher than the present-day value) occurred during deglaciations and early in MIS 3. Dissolution maxima coincided with transitions to colder stages. The mass record of G. sacculifer better indicated preservation than did that of N. dutertrei or G. ruber. Dissolution-corrected Mg/Ca-derived SST records, like other SST records from marginal Indian Ocean sites, showed coolest temperatures of the last 150 ka in early MIS 3, when mixed layer temperatures were ∼4°C lower than present SST. Temperatures recorded by N. dutertrei showed the thermocline to be ∼4°C colder in MIS 3 compared to the Holocene (8 ka B.P.)

Large Area Mapping at 850 Microns. IV. Analysis of the Clump Distribution in the Orion B South Molecular Cloud

We present results from a survey of a 1300 arcmin^2 region of the Orion B South molecular cloud, including NGC 2024, NGC 2023, and the Horsehead Nebula (B33), obtained using the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope. Submillimeter continuum observations at 450 microns and 850 microns are discussed. Using an automated algorithm, 57 discrete emission features (``clumps'') are identified in the 850 micron map. The physical conditions within these clumps are investigated under the assumption that the objects are in quasi-hydrostatic equilibrium. The best fit dust temperature for the clumps is found to be T_d = 18 +/- 4 K, with the exception of those associated with the few known far infrared sources residing in NGC 2024. The latter internally heated sources are found to be much warmer. In the region surrounding NGC 2023, the clump dust temperatures agree with clump gas temperatures determined from molecular line excitation measurements of the CO molecule. The bounding pressure on the clumps lies in the range log(k^-1 P cm^3 K^-1) = 6.1 +/- 0.3. The cumulative mass distribution is steep at the high mass end, as is the stellar Initial Mass Function. The distribution flattens significantly at lower masses, with a turn-over around 3 -- 10 M_sun.Comment: 41 pages, 16 figures, accepted by Ap

Reactivity of TEMPO anion as a nucleophile and its applications for selective transformations of haloalkanes or acyl halides to aldehydes

Sodium 2,2,6,6-tetramethylpiperidine-N-oxide (TEMPO&#8722;Na+), generated by reduction of TEMPO· with sodium naphthalenide in THF, reacted with alkyl halides or acyl halides to produce O-alkylated or acylated TEMPOs, which were in turn oxidized with mCPBA or reduced with DIBAL-H to afford the corresponding aldehydes, thus accomplishing a new protocol for the halides-carbonyls conversion.</p

Evaluating the repeatability and set-up sensitivity of a large field of view distortion phantom and software for magnetic resonance-only radiotherapy

Background and purpose: Magnetic Resonance (MR)-only radiotherapy requires geometrically accurate MR images over the full scanner Field of View (FoV). This study aimed to investigate the repeatability of distortion measurements made using a commercial large FoV phantom and analysis software and the sensitivity of these measurements to small set-up errors. Materials and methods: Geometric distortion was measured using a commercial phantom and software with 2D and 3D acquisition sequences on three different MR scanners. Two sets of repeatability measurements were made: three scans acquired without moving the phantom between scans (single set-up) and five scans acquired with the phantom re-set up in between each scan (repeated set-up). The set-up sensitivity was assessed by scanning the phantom with an intentional 1 mm lateral offset and independently an intentional 1° rotation. Results: The mean standard deviation of distortion for all phantom markers for the repeated set-up scans was for all scanners and sequences. For the lateral offset scan of the markers agreed within two standard deviations of the mean of the repeated set-up scan (median of all scanners and sequences, range 78%–93%). For the 1° rotation scan, 80% of markers agreed within two standard deviations of the mean (range 69%–93%). Conclusions: Geometric distortion measurements using a commercial phantom and associated software appear repeatable, although with some sensitivity to set-up errors. This suggests the phantom and software are appropriate for commissioning a MR-only radiotherapy workflow

Bondi-Hoyle-Lyttleton Accretion onto a Protoplanetary Disk

Young stellar systems orbiting in the potential of their birth cluster can accrete from the dense molecular interstellar medium during the period between the star's birth and the dispersal of the cluster's gas. Over this time, which may span several Myr, the amount of material accreted can rival the amount in the initial protoplanetary disk; the potential importance of this `tail-end' accretion for planet formation was recently highlighted by Throop & Bally (2008). While accretion onto a point mass is successfully modeled by the classical Bondi-Hoyle-Lyttleton solutions, the more complicated case of accretion onto a star-disk system defies analytic solution. In this paper we investigate via direct hydrodynamic simulations the accretion of dense interstellar material onto a star with an associated gaseous protoplanetary disk. We discuss the changes to the structure of the accretion flow caused by the disk, and vice versa. We find that immersion in a dense accretion flow can redistribute disk material such that outer disk migrates inwards, increasing the inner disk surface density and reducing the outer radius. The accretion flow also triggers the development of spiral density features, and changes to the disk inclination. The mean accretion rate onto the star remains roughly the same with and without the presence of a disk. We discuss the potential impact of this process on planet formation, including the possibility of triggered gravitational instability; inclination differences between the disk and the star; and the appearance of spiral structure in a gravitationally stable system.Comment: Accepted to ApJ. Version 2 replaces a mislabeled figure. Animations of the simulations and a version of the paper with slightly less-compressed images can be found at http://origins.colorado.edu/~moeckel/BHLpape

Experience of providing cultural safety in mental health to Aboriginal patients: A grounded theory study

The need for mental health clinicians to practice cultural safety is vital in ensuring meaningful care and in moving towards improving the mental health outcomes for Aboriginal people. The concept of cultural safety is particularly relevant to mental health professionals as it seeks to promote cultural integrity and the promotion of social justice, equity and respect. A substantive theory that explained the experience of providing cultural safety in mental health care to Aboriginal patients was developed using grounded theory methodology. Mental health professionals engaged in a social psychological process, called seeking solutions by navigating the labyrinth to overcome the experience of being unprepared. During this process participants moved from a state of being unprepared to one where they began to navigate the pathway of cultural safety. The findings of this research suggest health professionals have a limited understanding of the concept of cultural safety. The experience of providing cultural safety has not been adequately addressed by organizations, health services, governments, educational providers and policy makers. Health services, organizations and government agencies must work with Aboriginal people to progress strategies that inform and empower staff to practice cultural safety