I. D. Reid

A Monte Carlo simulation technique has been used to test the accuracy of electron energy distribution functions and transport coefficients calculated using conventional numerical solutions of Boltzmann's equation based on a two-term approximation. The tests have been applied to a number of model gases, some of which have characteristics close to those of real gases, and include cases where the scattering is anisotropic. The results show that, in general, previous application of the numerical solution to real gases has been valid.

Bimolecular rate constants for the thermal chemical reactions of muonium (Mu) with hydrogen and deuterium—Mu+H2→MuH+H and Mu+D2→MuD+D—over the temperature range 473–843 K are reported. The Arrhenius parameters and 1σ uncertainties for the H2 reaction are log A (cm3 molecule−1 s−1)=−9.605±0.074 and Ea =13.29±0.22 kcal mol−1, while for D2 the values are −9.67±0.12 and 14.73±0.40, respectively. These results are significantly more precise than those reported earlier by Garner et al. For the Mu reaction with H2 our results are in excellent agreement with the 3D quantum mechanical calculations of Schatz on the Liu–Siegbahn–Truhlar–Horowitz potential surface, but the data for both reactions compare less favorably with variational transition-state theory, particularly at the lower temperatures.

The thermally averaged depolarization cross sections, \ensuremath{\sigma}${\ifmmode\bar\else\textasciimacron\fi{}}_{D}$(T), for Mu+${\mathrm{O}}_{2}$ electron spin exchange, have been measured by the muon spin relaxation (\ensuremath{\mu}SR) technique in a ${\mathrm{N}}_{2}$ moderator at total pressures near 1 atm over the temperature range 88--500 K. These values are related to the thermal spin-flip cross sections of interest (\ensuremath{\sigma}${\ifmmode\bar\else\textasciimacron\fi{}}_{\mathrm{SF}}$) by a simple numerical factor. At temperatures \ensuremath{\gtrsim}120 K, \ensuremath{\sigma}${\ifmmode\bar\else\textasciimacron\fi{}}_{D}$(T) is essentially temperature independent [with \ensuremath{\sigma}${\ifmmode\bar\else\textasciimacron\fi{}}_{\mathrm{SF}=(5.7\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\mathrm{\ensuremath{-}}16}}$ ${\mathrm{cm}}^{2}$], though exhibiting a slight tendency to increase with temperature. At lower temperatures, \ensuremath{\sigma}${\ifmmode\bar\else\textasciimacron\fi{}}_{\mathrm{SF}(\mathrm{T}}$) decreases noticeably. Comparison with the only currently available theoretical calculations of Mu(H)+${\mathrm{O}}_{2}$ spin-flip cross sections by Aquilanti, Grossi, and Lagan\`a [Hyperfine Interact. 8, 347 (1981)] on the potential-energy surface of Farantos et al. [Mol. Phys. 34, 947 (1977)] gives poor agreement with the data, particularly in their temperature dependence. The present results for \ensuremath{\sigma}${\ifmmode\bar\else\textasciimacron\fi{}}_{\mathrm{SF}(\mathrm{T}}$) for Mu+${\mathrm{O}}_{2}$ qualitatively exhibit the same trend with temperature as found by Desaintfuscien and Audoin [Phys. Rev. A 13, 2070 (1976)] for H-H spin exchange over a comparable temperature range, but the H-H cross sections are, surprisingly, about four times larger. Comparisons with the experimental H+${\mathrm{O}}_{2}$ spin-exchange cross sections of Anderle et al. [Phys. Rev. A 23, 34 (1981)] and of Gordon et al. [JETP Lett. 17, 395 (1973)], indicate a significant isotope effect, with \ensuremath{\sigma}${\ifmmode\bar\else\textasciimacron\fi{}}_{\mathrm{SF}(\mathrm{H})\mathit{\ensuremath{\gtrsim}}1.5\mathit{\ensuremath{\sigma}}{\ifmmode\bar\else\textasciimacron\fi{}}_{\mathrm{SF}}}$(Mu). While this effect can be qualitatively understood in terms of the differing numbers of partial waves involved, detailed theoretical calculations on more recent potential-energy surfaces for ${\mathrm{HO}}_{2}$ are called for.

Abstract Incorporation of muonium, the ultra‐light isotope of hydrogen with a mass of only one‐ninth the mass of H, leads to pronounced isotope effects in hyperfine coupling constants of radicals. They reflect the mass dependence of the internal dynamics. A detailed analysis is presented for the cyclohexadienyl and the cyclopentyl radicals. It is concluded that the isotope dependent bond length in an anharmonic potential accounts quantitatively for the observed effects in rigid species.

A new tracking detector is under development for use by the CMS experiment at the High-Luminosity LHC (HL-LHC). A crucial requirement of this upgrade is to provide the ability to reconstruct all charged particle tracks with transverse momentum above 2–3 GeV within 4 μs so they can be used in the Level-1 trigger decision. A concept for an FPGA-based track finder using a fully time-multiplexed architecture is presented, where track candidates are reconstructed using a projective binning algorithm based on the Hough Transform, followed by a combinatorial Kalman Filter. A hardware demonstrator using MP7 processing boards has been assembled to prove the entire system functionality, from the output of the tracker readout boards to the reconstruction of tracks with fitted helix parameters. It successfully operates on one eighth of the tracker solid angle acceptance at a time, processing events taken at 40 MHz, each with up to an average of 200 superimposed proton-proton interactions, whilst satisfying the latency requirement. The demonstrated track-reconstruction system, the chosen architecture, the achievements to date and future options for such a system will be discussed.

Values of the electron drift velocity, the longitudinal diffusion coefficient and the transverse diffusion coefficient, for electron swarms in nitrogen over the range 50 Td<or=E/N<or=500 Td have been determined by a method of counting and analysing the photons produced by such an electron swarm in a drift tube. A measure of the nitrogen E state deactivation rate is presented.

The avoided-level-crossing relaxation of a polarized muon spin-label was used to investigate the reorientational dynamics of muonated cyclohexadienyl radicals in NaZSM-5 with SiO2/Al2O3 ratios of 670 and 900 and loadings of one and two benzene molecules per unit cell. It was found that on a critical time scale of about 50 ns the radical performs fast uniaxial rotation about the axis perpendicular to the molecular plane. Superimposed on this there is a two-site jump motion between two orientations that differ by an angle of 110° and 1.0 kJ mol-1 in energy. This causes increasing averaging of the orientations above 50 K. It is particularly extensive but still not isotropic in a temperature range between 200 and 450 K. Below 50 K, the uniaxial rotation slows down below the critical time scale of the experiment, and below 20 K any motion is frozen. It is suggested that such a high reorientational mobility is possible only for the radicals occupying sites at the channel intersections. Above ca. 450 K, the reversible appearance of new broad spectral features suggests that new sites with much lower mobility become thermally accessible. These may be located inside the channels.

Despite the introduction of training salaries for Postgraduate Certificate of Education (PGCE) students, a substantial increase in enquiries (Tabberer, 2000) and some reported increase in the actual number of applications for primary teacher education courses (Campbell, 2000), recruitment overall has declined significantly, from 24,994 applications in 1994 to 9,875 in 1999 (Gates, 1999). Higher entry qualifications will not readily be imposed on a smaller pool of applicants if the educational characteristics of those applicants remain at the same level (generally considered to be low: House of Commons, 1997). Specific subject-knowledge for teaching may be enhanced by increased emphasis on first degrees and thus recruitment to primary PGCE courses, through the discriminating allocation of training salaries and as an outcome of the Secretary of State’s description of the Bachelor of Education (B.Ed.) degree as a ‘sub-degree undergraduate course’ (McAvoy, citing Hansard, 2000), but the PGCE neither ensures adequate coverage of shortage subjects nor the whole curriculum competence required of most primary teachers (Thornton, 1998). Despite the introduction of training salaries for PGCE students, starting in September 2000, recruitment of ethnic minority and male students remains low (Barnard, 2000, reports just a 5 per cent increase in applications from men and a 5 per cent increase in enquiries from ethnic minorities) and there is strong evidence that the teaching profession in England is becoming increasingly feminised (Howson, 1998).

Bimolecular rate constants for the thermal chemical reactions of muonium (Mu) with the halogen gases—Mu+X2→MuX+X—are reported over the temperature ranges from 500 down to 100, 160, and 200 K for X2=F2,Cl2, and Br2, respectively. The Arrhenius plots for both the chlorine and fluorine reactions show positive activation energies Ea over the whole temperature ranges studied, but which decrease to near zero at low temperature, indicative of the dominant role played by quantum tunneling of the ultralight muonium atom. In the case of Mu+F2, the bimolecular rate constant k(T) is essentially independent of temperature below 150 K, likely the first observation of Wigner threshold tunneling in gas phase (H atom) kinetics. A similar trend is seen in the Mu+Cl2 reaction. The Br2 data exhibit an apparent negative activation energy [Ea=(−0.095±0.020) kcal mol−1], constant over the temperature range of ∼200–400 K, but which decreases at higher temperatures, indicative of a highly attractive potential energy surface. This result is consistent with the energy dependence in the reactive cross section found some years ago in the atomic beam data of Hepburn et al. [J. Chem. Phys. 69, 4311 (1978)]. In comparing the present Mu data with the corresponding H atom kinetic data, it is found that Mu invariably reacts considerably faster than H at all temperatures, but particularly so at low temperatures in the cases of F2 and Cl2. The current transition state calculations of Steckler, Garrett, and Truhlar [Hyperfine Interact. 32, 779 (986)] for Mu+X2 account reasonably well for the rate constants for F2 and Cl2 near room temperature, but their calculated value for Mu+Br2 is much too high. Moreover, these calculations seemingly fail to account for the trend in the Mu+F2 and Mu+Cl2 data toward pronounced quantum tunneling at low temperatures. It is noted that the Mu kinetics provide a crucial test of the accuracy of transition state treatments of tunneling on these early barrier HX2 potential energy surfaces.

Teachers obviously serve as the medium for causing the result of policy as they carry it into schools and classrooms and deliver it to pupils. They mediate between education policy and practice. Knowledge of the exact nature and effects of this vital role is limited. Drawing on a range of research and evaluation of both national and local policy in practice, carried out by the authors in England, this paper illustrates how teachers mediate policy and the resulting outcomes. Further, it proposes a typology of teacher adaptation to education policy. The paper argues that as yet the appropriate professional role for teachers within policy‐making and implementation has not been achieved, and outlines what this might be. Finally, it outlines some implications for teacher education.

This paper illustrates some of the tensions and contradictions in schools' attempts to develop parental and family involvement through a case study of parental involvement in an Education Action Zone. It focuses on how schools constructed parental involvement, the kinds of work they engaged in, the issues raised in managing and resourcing parental involvement projects, the perceived benefits of running the projects and the likelihood of the projects being sustainable. It is argued that the models of parental involvement that schools developed had important consequences for the role parents were allowed to play. Varying roles impose different kinds of demands on schools and parents and require different kinds of relationship between schools, parents and the local community. The more expansive the view of parental involvement, the greater the costs in running such projects and, hence, particularly in poor areas, the less chance of them being sustainable. Moreover, there were evident contradictions between the standards and inclusion dimensions of parental involvement projects. In particular, there was, and is, an evident tension for the schools around constructing parents as a resource for schools to tap into in the drive to raise standards and constructing the school as a resource for parents and the wider community to tap into in the drive to promote local regeneration and inclusion. This is being resolved in favour of the standards agenda.

LHC@home was launched as a BOINC project in 2004 as an outreach project for CERN’s 50 years anniversary. Initially focused on the accelerator physics simulation code SixTrack, the project was expanded in 2011 to run other physics simulation codes on Linux thanks to virtualisation. Later on the experiment and theory applications running on the LHC@home platform have evolved to use containers and take advantage of the CVMFS file system as well as content delivery networks. Furthermore, a substantial part of the contributed computing capacity nowadays is provided as opportunistic back-fill from data centers with spare capacity, in addition to enthusiastic volunteers. The paper will address the challenges with this distributed computing model, new applications to exploit GPUs and the future outlook for volunteer computing.

PART ONE: INTRODUCTION The Reform - Ivan Reid Change or Transformation of Initial Teacher Training? Issues and Themes Raised by the Evidence - Roy Griffiths PART TWO: TOWARDS EFFECTIVE PARTNERSHIP PRACTICE The Perceived Values of the Role Activities of Mentors and Curricular, Professional and General Tutors - S Rothwell, E Nardi and D McIntyre Communication and Innovation - Nicholas Foskett, Mary Ratcliffe and David Brunner Managing Further Professional Studies - Hugh Busher and Peter King Students' Perceptions of Consistency and Coherence - Nigel Wright and Jeff Moore Lessons Unlearnt? Aspects of Training Licensed Teachers - Conor Galvin The Extra Pair of Hands Comes with a Free Brain - Derek Haylock I'm Sorry, but There's Not Enough Money for a Third Teaching Practice Visit - Dylan Wiliam PART THREE: MENTORING AND SUPPORTING STUDENT-TEACHERS Mentoring Articled Science Teachers - Bob Campbell and Alastair Horbury 'In at the Beginning' - Kath Aspinwall, Viv Garrett and Gwyneth Owen-Jackson A Pilot Partnership Mentors in English and Mathematics - Pat Drake and Lisa Dart Positive Mentoring and the Novice-Expert - Val Brooks, Terence Fitch and Martin Robinson Student-Teachers and Their Professional Encounters - Hilary Constable and Jerry Norton How Teachers Support Student Learning - Jill Collison and Anne Edwards Peer Support - Kate Hawkey PART FOUR: STUDENTS LEARNING TO TEACH The Importance of 'Bad' Lessons - Rod Bramald et al Student Learning Experiences in Pre- and Post-Reform Courses - Alma Harris Student-Teachers' Thinking - Chris Kyriacou and Mei Lin Withdrawals from PCGE Courses - Margaret Sands and Pam Bishop Agendas in Conflict? - Linda Fursland New Teachers Reflecting on Their Training - Lynn D Newton PART FIVE: HEAD TEACHERS' AND OTHERS' VIEWS OF THE CHANGES Headteachers', Parents', Students' and Tutors' Responses to the Reform of Primary ITE - Andrew Hannan Headteachers' Perspectives on Primary Education Policy - Bruce Carrington and Peter Tymms Off Site, In Tune, On Target - Margaret Alfrey and Carl Parsons PART SIX: CONCLUSION Implementing Change in Teacher Education - Hilary Constable

The reaction kinetics for the addition of the muonium (Mu=μ+e−) atom to C2H4 and C2D4 have been measured over the temperature range 150–500 K at (N2) moderator pressures near 1 atm. A factor of about 8 variation in moderator pressure was carried out for C2H4, with no significant change seen in the apparent rate constant kapp, which is therefore taken to be at the high pressure limit, yielding the bimolecular rate constant kMu for the addition step. This is also expected from the nature of the μSR technique employed, which, in favorable cases, gives kapp=kMu at any pressure. Comparisons with the H atom data of Lightfoot and Pilling, and Sugawara et al. and the D atom data of Sugawara et al. reveal large isotope effects. Only at the highest temperatures, near 500 K, is kMu/kH given by its classical value of 2.9, from the mean velocity dependence of the collision rate but at the lowest temperatures kMu/kH≳30/1 is seen, reflecting the pronounced tunneling of the much lighter Mu atom (mμ=1/9 mp). The present Mu results should provide accurate tests of reaction theories on currently available ab initio surfaces.

The TRIUMF low energy muon channel, M20, was completely rebuilt in 1983. Amongst the features incorporated into the new channel is a 3 m long Wien filter or dc separator. For surface and sub-surface μ+ beams, the magnetic field of this device is sufficient to rotate the muon spin from its natural orientation, antiparallel to the beam momentum, by 90° into a transverse orientation. The performance of this muon “spin rotator” is described.

The authors present measurements of the cross sections for the ejection of electrons from helium atoms by protons, differential in the electron ejection angle and energy. The proton energies range from 20 to 100 keV, while the electron energies range from 5 to 100 eV and the ejection angles from 0 to 100 degrees . The measurements are normalised by comparing the estimates of the total cross section, derived from double integration of the measured distributions, with published absolute values of the ionisation cross section. Although the energy distribution agrees with existing data, there is a substantial divergence in the angular behaviour. As the measurements include the zero-degree region, the electron capture into the continuum (ECC) peak is examined in detail and an estimate of the total cross section for this process is made over a range of proton energies.

Goodness-of-fit statistics measure the compatibility of random samples against some theoretical or reference probability distribution function. The classical one-dimensional Kolmogorov-Smirnov test is a non-parametric statistic for comparing two empirical distributions which defines the largest absolute difference between the two cumulative distribution functions as a measure of disagreement. Adapting this test to more than one dimension is a challenge because there are 2d-1 independent ways of ordering a cumulative distribution function in d dimensions. We discuss Peacock's version of the Kolmogorov-Smirnov test for two-dimensional data sets which computes the differences between cumulative distribution functions in 4n2 quadrants. We also examine Fasano and Franceschini's variation of Peacock's test, Cooke's algorithm for Peacock's test, and ROOT's version of the two-dimensional Kolmogorov-Smirnov test. We establish a lower-bound limit on the work for computing Peacock's test of Ω(n2lgn), introducing optimal algorithms for both this and Fasano and Franceschini's test, and show that Cooke's algorithm is not a faithful implementation of Peacock's test. We also discuss and evaluate parallel algorithms for Peacock's test.

Abstract The LHC@Home BOINC project has provided computing capacity for numerical simulations to researchers at CERN since 2004, and has since 2011 been expanded with a wider range of applications. The traditional CERN accelerator physics simulation code SixTrack enjoys continuing volunteers support, and thanks to virtualisation a number of applications from the LHC experiment collaborations and particle theory groups have joined the consolidated LHC@Home BOINC project. This paper addresses the challenges related to traditional and virtualized applications in the BOINC environment, and how volunteer computing has been integrated into the overall computing strategy of the laboratory through the consolidated LHC@Home service. Thanks to the computing power provided by volunteers joining LHC@Home, numerous accelerator beam physics studies have been carried out, yielding an improved understanding of charged particle dynamics in the CERN Large Hadron Collider (LHC) and its future upgrades. The main results are highlighted in this paper.

The dynamics of the muonium (Mu) adduct to C60 in the crystalline state have been investigated using avoided level crossing muon spin resonance (ALC-μSR). The motion of C60 in the orientationally ordered phase (T < 260 K) is well described by a spherical diffusion or isotropic jump-reorientation motion with an Arrhenius activation energy of 176(1) meV and a frequency factor of 2.95(13) × 10−12 s. This is in striking contrast to the behaviour of MuC70 adducts whose reorientational motion fits well in a pseudo-static model with a temperature dependent order parameter.

TheμSR Facility Instruments presently available at PSI and the envisaged medium- and long-term developments are presented. The plans focus on further upgrades of the existing instruments and the development of new techniques using the very high fluxes becoming available at PSI, in particular the setup of a beamline with a fast kicker for ‘muons on request’ (MORE) and the development of very low energy muon beams.

Positive muons injected into solid ${\mathrm{C}}_{70}$ form a vacuumlike muonium (Mu) state with a 25% probability. This state is attributed to muons inside the ${\mathrm{C}}_{70}$ cage (${\mathrm{C}}_{70}$:Mu). In addition, three different types of muonated free radicals, distinguishable by their hyperfine coupling constants, are observed. These radicals are attributed to muonium addition on the outside of the ${\mathrm{C}}_{70}$ molecule at different sites. The hyperfine parameters of these radicals reflect the different degrees of delocalization of the unpaired electron. The temperature dependence of the depolarization rates yields information on the dynamics of the ${\mathrm{C}}_{70}$ molecules.

The effect of Heisenberg spin exchange on the avoided level crossing (ALC) μSR spectra of organic free radicals is discussed within the framework of a two-state jump model. Numerical expressions are derived which also apply to chemical exchange processes. A simple expression relating ALC amplitude and linewidth to the exchange and chemical reaction rates is inferred from numerical calculations. The theory is applied to the kinetics of the radical-radical reaction between the muonated cyclohexadienyl radical and the diphenylpicrylhydrazyl radical (DPPH•) which is investigated by means of transverse field (TF) and ALC μSR. A total rate constant of 4.7 (5) × 109 M−1 s−1 is found. ALC experiments allow its separation into a spin exchange contribution of ≈ 75% and a chemical contribution of ≈ 25%. The efficiency of the chemical reaction amounts to ≈ 13 per encounter of electron singlet radical pairs. The strong exchange-coupling limit holds true, and 10−10 s is obtained as an upper limit for the radical pair lifetime at room temperature.

This paper traces the dramatic proliferation of leadership roles in English primary and secondar schools, due mainly to central government education policy of the past two decades. This has transformed schools from relatively simple to highly complex organizations and has impacted on the working conditions of, and demands on, teachers, together with many aspects of schooling. These changes are illustrated with typical examples of schools' leadership structures and their functioning. Interview data provide teachers' views on, and reactions to, the changes in school leadership. The paper also reviews the ways in which teacher education institutions have responded in terms of providing initial and in‐service education and training to equip the profession for this new and developing challenge. It examines the reception of such programmes by teachers and the reported impact on schools' management and the role of leadership within it.

Abstract Avoided level crossing muon spin resonance effects are observed with polycrystalline norbornene in its plastic phase and analysed in terms of axial hyperfine anisotropy. The results agree with those of previous single crystal measurements. It is shown that the technique is sensitive to the detection of small anisotropies, and that it is ideally suited for the study of reorientational dynamics in polycrystalline or amorphous environments.

The transport properties of an electron swarm drifting and diffusing in hydrogen as determined from a numerical solution of Boltzmann's equation are compared with those derived previously from a Monte Carlo simulation. The same set of cross sections has been used with each method to calculate transport coefficients in the range 0�5 .;;; EIN.;;; 200 Td. The comparison shows that the Boltzmann analysis is valid in this case whenever ionization is not significant.

Cyclohexadienyl radicals have been observed in Na-X zeolite at ambient temperature by means of the muon spin rotation technique.

A technique has been tested for the first time which combines the advantages of continuous and pulsed muon beams, namely high time resolution and low background in time-differential μSR experiments. In addition, the method allows the muon beam to be split and two μSR experiments run simultaneously at full intensity without any interference between the instruments.

The dynamic behaviour of the cyclohexadienyl radical adsorbed on plain silica and on a silica supported Pd catalyst is investigated by means of the avoided-level-crossing muon spin resonance technique. The influence of benzene coverage and of surface texture on the hyperfine coupling constants, on the signal amplitudes and on the mobility of the radical is studied. Information about surface diffusion is obtained using a theoretical model based on a stochastic Liouville formalism. The radical mobility increases with coverage of the surface with benzene. Arrhenius parameters are discussed within the framework of a hopping model based on transition-state theory for surface diffusion. It is suggested that the dynamics of the surface hydroxyl groups play a crucial role in the diffusion process.

The adduct radicals (ArCHOMu˙) have been formed by muonium addition to the carbonyl group of benzaldehyde and its derivatives. The muon coupling is found to be highly sensitive to the nature of substituents in the benzene ring, being increased by electron releasing groups. This bears relevance to their properties in Group 1 and Group 2 exchange zeolite-X, in which the coupling is decreased by interactions between the aromatic π-electrons and the cation: the effect increasing in the order of decreasing ionic radius, as the electron withdrawing power of the ring is increased by polarization of the π-electrons towards the cation. For the radical derived from benzaldehyde itself, a strong dependence is also found on the solvent in which it is dissolved. It is suggested that this may be used in the study of solvent effects, particularly H-bonding, pertinent to organic and bio-organic media. Electronic substituent effects are also studied in substituted PhCHOMu˙ radicals, and in cyclohexadienyl radicals formed by muonium addition to the aromatic ring, the latter showing evidence of captodative stabilization, when an electron donor substituent is present with the electron accepting CHO group.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReorientational Dynamics of Solid C70 Probed by Positive MuonsRoderick M. Macrae, Kosmas Prassides, Ian M. Thomas, Emil Roduner, Christof Niedermayer, Ulrich Binninger, Christian Bernhard, Anselm Hofer, and Ivan D. ReidCite this: J. Phys. Chem. 1994, 98, 47, 12133–12141Publication Date (Print):November 1, 1994Publication History Published online1 May 2002Published inissue 1 November 1994https://doi.org/10.1021/j100098a005RIGHTS & PERMISSIONSArticle Views63Altmetric-Citations18LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts

Abstract Rate constants have been measured for the reaction of the light hydrogen isotope muonium with benzene and 2,3‐dimethylbutadiene‐1,3 in the gas phase and in several solvents. Comparison with H atom data reveals (1) appreciable kinetic isotope effects, (2) a strong contribution of tunnelling for the activated reaction with benzene, (3) encounter controlled reaction for Mu addition to the diene, (4) a mass dependence of the diffusion constant of hydrogen isotopes in solution, and (5) an enhancement of the rate constant in solution over that in the gas phase by a factor, except for water, of the inverse Ostwald solubility coefficient for hydrogen. The isotope‐dependent reduction of the solvent effect in water is tentatively ascribed to the dynamics of the clathrate‐like structure when the hydrogen atom reacts.

Summary This study shows that Sunday School attendance was related to measurable differences in adolescents' religious and moral attitudes and practice, but only partly related to their knowledge in these areas. This relationship was true of past attendance but particularly strong in relation to current attendance. In respect to past attendance the measures differentiated boys in terms of experience but not girls. No sexual differences were identified in relation to current attendance. The study further revealed significant differences in scores between the scholars of two Sunday Schools. A discussion of possible explanations of these differences and the need for further specific investigation is included.

Abstract Muon Spin Relaxation and Avoided Level Crossing (ALC) measurements of ferrocene are reported. The main features observed are five high field resonances in the ALC spectrum at about 3.26, 2.44, 2.04, 1.19 and 1.17 T, for the low‐temperature phase at 18 K. The high‐temperature phase at 295 K shows that only the last feature shifted down to about 0.49 T and a muon spin relaxation peak at about 0.106 T which approaches zero field when reaching the phase transition temperature of 164 K. A model involving three muoniated radicals, two with muonium addition to the cyclopentadienyl ring and the other to the metal atom, is postulated to rationalise these observations. A theoretical treatment involving spin‐orbit coupling is found to be required to understand the Fe–Mu adduct, where an interesting interplay between the ferrocene ring dynamics and the spin‐orbit coupling of the unpaired electron is shown to be important. The limiting temperature above which the full effect of spin‐orbit interaction is observable in the μSR spectra of ferrocene was estimated to be 584 K. Correlation time for the ring rotation dynamics of the Fe–Mu radical at this temperature is 3.2 ps. Estimated electron g values and the changes in zero‐field splittings for this temperature range are also reported.

The kinetics of the addition reaction of muonium (Mu) to acetylene have been studied in the gas phase at N2 moderator pressures mainly from ∼800 to 1000 Torr and over the temperature range from 168 to 446 K, but also down to 200 Torr at 168 K and over a much higher range of pressures, from 10 to 44 bar at 295 K, demonstrating pressure-independent rate constants, kMu(T). Even at 200 Torr moderator pressure, the kinetics for Mu + C2H2 addition behave as if effectively in the high-pressure limit, giving k∞ = kMu due to depolarization of the muon spin in the MuC2H2 radical formed in the addition step. The rate constants kMu(T) exhibit modest Arrhenius curvature over the range of measured temperatures. Comparisons with data and with calculations for the corresponding H(D) + C2H2 addition reactions reveal a much faster rate for the Mu reaction at the lowest temperatures, by 2 orders of magnitude, in accord with the propensity of Mu to undergo quantum tunneling. Moreover, isotopic atom exchange, which contributes in a major way to the analogous D atom reaction, forming C2HD + H, is expected to be unimportant in the case of Mu addition, a consequence of the much higher zero-point energy and hence weaker C–Mu bond that would form, meaning that the present report of the Mu + C2H2 reaction is effectively the only experimental study of kinetic isotope effects in the high-pressure limit for H-atom addition to acetylene.

A new tracking system is under development for operation in the CMS experiment at the High Luminosity LHC. It includes an outer tracker which will construct stubs, built by correlating clusters in two closely spaced sensor layers for the rejection of hits from low transverse momentum tracks, and transmit them off-detector at 40 MHz. If tracker data is to contribute to keeping the Level-1 trigger rate at around 750 kHz under increased luminosity, a crucial component of the upgrade will be the ability to identify tracks with transverse momentum above 3 GeV/c by building tracks out of stubs. A concept for an FPGA-based track finder using a fully time-multiplexed architecture is presented, where track candidates are identified using a projective binning algorithm based on the Hough Transform. A hardware system based on the MP7 MicroTCA processing card has been assembled, demonstrating a realistic slice of the track finder in order to help gauge the performance and requirements for a full system. This paper outlines the system architecture and algorithms employed, highlighting some of the first results from the hardware demonstrator and discusses the prospects and performance of the completed track finder.

Abstract Activation parameters for the surface dynamics of radicals produced by the addition of muonium to the unsaturated organic substrates cyclopentene, benzene, tetramethylethylene [2,3‐dimethylbut‐2‐ene (TME)] and 2,3‐dimethylbuta‐1,3‐diene (DMBD) adsorbed in the zeolites Na‐mordenite and NaX and on silica have been determined by means of transverse‐field muon spin rotation spectroscopy. This allows the study of the influence of adsorption by the different surfaces on these parameters. The temperature dependences of the muon hyperfine couplings were also studied and were found to be highly sensitive to the type of catalyst, and so to the nature of the adsorption site.

The kinetics of the addition reaction of O2 to the ethyl radical has been investigated as a function of temperature (259−425 K) and pressure (1.5−60 bar) using the muon spin relaxation technique in longitudinal magnetic fields. Within this temperature range at 1.5 bar, the chemical reaction is represented by an Arrhenius rate law with an activation energy of −4.4(4) kJ mol-1 and an apparent frequency factor of 1.3(2) × 10-12 cm3 molecule-1 s-1. The high-pressure limit of the rate constant at 294 K amounts to = 8.7(8) × 10-12 cm3 molecule-1 s-1. Within error, this limit has been reached at 1.5 bar. The rate coefficient for spin exchange, kex = 2.8(2) × 10-10 cm3 molecule-1 s-1, is collision controlled. The results for kch agree well with experimental literature values, but the temperature dependence is more pronounced than that predicted on the basis of a RRKM extrapolation from low-pressure data. The theoretical basis for the analysis of experimental data is given, and the results are discussed.

Thermal (300 K) ion–molecule reaction rates are measured, using the µSR (muon spin rotation) technique, for the muonated rare gas molecular ions HeMu + and NeMu + reacting with NO, O 2 , N 2 O, NH 3 , CF 4 , C 2 H 4 , TMS, and CH 3 NO 2 . In almost every case (excepting O 2 ), both charge transfer (k e ) and muon transfer (k µ ) contribute to the reaction rate. Reaction is believed to occur from ro-vibrational excited states, [HeMu + ]* and [NeMu + ]*, due to the poor efficiency of He and Ne moderators for collisional deactivation. The total experimental rate constants, k exp = k µ + k e , are generally in excellent agreement with total capture rates predicted by the simple ADO theory, regardless of the degree of internal excitation. Comparisons with literature values for corresponding protonated ion reaction rates with O 2 and C 2 H 4 reveal little or no isotope effect, although it is noted that these reactions are dominated by proton transfer, in contrast to the µSR results.

The front end driver (FED), is a 9U 400 mm VME64x card designed for reading out the compact muon solenoid (CMS), silicon tracker signals transmitted by the APV25 analogue pipeline application specific integrated circuits. The FED receives the signals via 96 optical fibers at a total input rate of 3.4 GB/sec. The signals are digitized and processed by applying algorithms for pedestal and common mode noise subtraction. Algorithms that search for clusters of hits are used to further reduce the input rate. Only the cluster data along with trigger information of the event are transmitted to the CMS data acquisition system using the S-LINK64 protocol at a maximum rate of 400 MB/sec. All data processing algorithms on the FED are executed in large on-board field programmable gate arrays. Results on the design, performance, testing and quality control of the FED are presented and discussed

first year of a UK-India Education and Research Initiative (UKIERI), "Widening Participation: Diversity, isolation or integration in Higher Education?"Over a three year period this project will explore issues of diversity and integration, social cohesion and separation, equality and discrimination as experienced by students and staff on higher education (HE) campuses in India and the UK.Initial findings suggest that separation of groups on the HE campuses studied is pervasive and ubiquitous.While some such separation may be for supportive reasons, convenience, or inertia, at other times it is due to overt discrimination on the grounds of race, region, nationality, caste, class, religion, age or gender.However, most respondents said that greater integration was both desirable and possible.

An activation energy of 10.6 ± 1.4 kJ mol−1 was determined for the reorientational diffusion of 1,1-dichloroethyl radicals sorbed in silica gel by transverse-field muon spin rotation (TF-MuSR) spectroscopy, and was confirmed by longitudinal-field muon spin relaxation (LF-MuSRx) measurements, which gave a value of 10.9 ± 0.7 kJ mol−1. Also according to TF-MuSR measurements, the activation energy for this radical sorbed in kaolin powder is 11.0 ± 1.3 kJ mol−1, which was within experimental error of that obtained from an LF-MuSRx study (12.3 ± 0.8 kJ mol−1). The LF-MuSRx method also revealed the presence of an additional, more mobile, fraction of 1,1-dichloroethyl radicals in both silica and kaolin with activation energies of 2.6 ± 0.4 and 2.4 ± 0.2 kJ mol−1, respectively. Copyright © 2000 John Wiley & Sons, Ltd.

We present the first muon spin rotation/relaxation study of a nematic liquid crystal (5CB). We identify four different positions for muonium addition to this compound by correlating the dominant peaks in the Fourier transform of the muon precession signal obtained in an applied transverse magnetic field. Experiments performed in a longitudinal field are used to probe changes in individual molecular dynamics at the solid-nematic transition. High field avoided level crossing spectroscopy reveals four $\ensuremath{\Delta}M=0$ transitions which can be fitted using simplified models of collective molecular dynamics appropriate to the solid, nematic, and liquid phases.

A new drift tube technique incorporating electron density sampling to locate the drifting electron swarms has been used to measure electron drift velocities in the range 0.14–1.4 Td. The data were obtained at several pressures from 0.2 to 0.5 kPa. The estimated accuracy ranges from 2% at 1.4 Td to 5% at 0.14 Td.

Abstract Avoided level crossing muon spin resonance spectra are reported for the muon substituted cyclohexadienyl radical which is formed on irradiation of benzene adsorbed on porous silica and in NaZSM‐5. The shapes of the resonances are discussed in terms of the reorientation dynamics of the adsorbed radical and of freezing of the pore‐confined benzene.

When benzene is sorbed into activated carbon powder, two distinct fractions are found using longitudinal field muon spin relaxation measurements, and are characterized by activation energies of 6 and 26 kJ mol−1 in respect of molecular reorientation. This is due to location of benzene in large (meso and macro) pores and micropores, respectively; escape from the latter is accompanied by a large, positive activation entropy of +52 J mol−1 K−1. Copyright © 2000 John Wiley & Sons, Ltd.

An error has been found in the computer codes used in the Monte Carlo simulations. The correction for this error alters some of the values of Dol by up to several per cent. The conclusions presented in the paper are however not affected.

Spin-restricted Hartree—Fock molecular orbitals calculations have been performed for Cn70 (−6 ⩽ n ⩽ + 6) at a MNDO type semi-empirical level based on the PM3 parameterization. The optimized geometries reveal interesting variations in bond lengths. The neutral molecule and the triplet states of the two ions with n = ± 4 have D5h symmetry, the other ions have lower symmetry. Significant charge polarization results in molecular electric quadrupole moments. The consequences of structure and of charge distribution with respect to selectivity towards chemical reaction and to packing in the solid state are discussed.

Summary The paper explores the important but neglected field of primary schoolchildren's attitudes towards the environment using a specifically designed scale in Arabic and English. It reports attitude differences towards the environment and three domains -- pollution, waste and animals and plants -- according to nationality and gender. Overall the findings show that environmental education programmes produce only slightly positive attitudes. Consideration is given to the further research required to enhance such programmes.

List of Tables. Acknowledgements. Preface. Part I: Social Class and This Book: . Social Class: a Subject for all Seasons. Social Class in Research. About This Book. Part II: The Social Classes in Britain:. The Distribution of Social Class in Britain. How the Public Sees Social Class. Part III: Life--Chances. Birth, Infancy and Childhood. Health. Life--Style and Health:. Use of Health Services. Mortality. Life Expectancy. Overview. Part IV: Income, Wealth, Poverty and Expenditure:. Income. Wealth. Poverty. Expenditure. Part V: Work, Unemployment and Social Mobility:. Work. Unemployment. Social Mobility. Part VI: Family, Children and Home:. The Family. Children. The Home. Part VII:. Education. Adults and Education. Childrena s Schooling and Education. Part VIII: Religion, Crime, Law, Politics and Opinion:. Religion. Crime and the Law. Politics. Opinion. Part IX: Leisure and the Media:. Home--Based Leisure. Out--of--Home Activities. Part X: Class in a Classless Society: . Appendices. References and Author Index. Subject Index.

Abstract The formation of a molecular radical following muon implantation in sulphur S 8 is established experimentally by level crossing resonance. The position of the resonance determines the hyperfine constant as 233 ± 5 MHz. Of various possible assignments evaluated by ab initio molecular orbital calculations, the most promising appears to be the muonic sulfanyl radical, ṠMu.

Abstract Muonium atoms are found to add mainly to the N‐atom and to the ortho and meta positions in pyridine in almost equal amounts, giving pyridinyl and 2‐azacyclohexadienyl radicals and 3‐azacyclohexadienyl radicals, respectively (no addition was observed at the para site); on protonation, as in a sample of PyH + BF 4 − , the reactivity follows the positive charge density, being enhanced for addition to the N (H + ) position, reduced for the ortho / meta positions, and now conferring a significant yield of the para isomer. These results for genuine reactions of hydrogen atoms are discussed in view of studies of radical formation in these materials, made using EPR spectroscopy, when they are exposed to γ‐rays in cryogenic matrices, for which mechanisms involving charge‐neutralization of initial radical ions are proposed. Copyright © 2001 John Wiley &amp; Sons, Ltd.

The relationship between the muon electron hyperfine coupling constant and the CO bond stretching frequency of a series of organic carbonyl compounds at 300K has been investigated. A linear relationship is shown to exist between these two properties, but for the aromatic carbonyl compounds only. This observation is shown to be in agreement with the presently accepted hyperconjugative mechanism of the hyperfine interaction in these systems. Muonium addition to the ring systems of these compounds was also observed and the hyperfine frequencies assigned and discussed.

S ummary . A sample of 520 student teachers (344 females and 176 males) in eight colleges of education, completed an anglicised version of the Mehrabian need for achievement scale, a questionnaire measure in parallel male and female forms, together with other personality and attitudinal schedules. In four separate validation studies the Mehrabian scale was found to differentiate between students in terms of their self‐images, their intellectual achievement responsibility, and their occupational aspirations. The Mehrabian scale is an objectively‐scorable, easily‐administered measure of n'ach against which performance criteria can be established. Its use in future studies of student motivation is recommended.

From a study of imidazole derivatives using transverse-field muon spin rotation (TF-µSR) spectroscopy, it is found that muonium adducts are formed preferentially at the 2- and 5-position, the latter predominating. It is further concluded that muonium is the true precursor of these radicals, and so this approach is valid for the study of organic molecules, of biological relevance, in which muonium acts as a radioactive hydrogen atom probe (tracer) of reactions involving free H-atoms, such as are produced during the radiolysis of aqueous (intracellular) media.

"Primary School Teaching as a Career: The views of the successfully recruited." Journal of Education for Teaching, 27(1), pp. 111–112

A sample of over one thousand British primary schoolchildren completed the Crandall Intellectual Achievement Responsibility questionnaire. Comparisons with earlier American data provided results which suggested similarities. The Crandall scale is more closely related to attainment than to intelligence. Results are seen as indicating that high internalized reinforcement responsibility in academic situations acts as a motivating variable for attainment relatively independent of intelligence.

Abstract The kinetics of the addition reaction of O 2 to the tert ‐butyl radical has been investigated at 1.5 bar as a function of temperature (241–462 K) using the muon spin relaxation technique in longitudinal magnetic fields. The data are represented by k ch = 43 +88 ‐26 X 10 −10 T −0.96±0.21 cm 3 molecules −1 s −1 , or alternatively by an Arrhenius activation energy of −2.4(0.7) kJ mol −1 and an apparent frequency factor of 68(19)x10 −13 cm 3 molecules −1 s −1 . The results of these temperature‐dependent measurements agree well with an experimental literature value at room temperature, but disagree with a more recent estimate by a factor of six.

Magnetic Resonance in ChemistryVolume 38, Issue 13 p. S49-S57 Research Article Hydrogen radioisotopic labelling studies using muonium: properties of thiyl radicals potentially relevant to cellular membrane damage Christopher J. Rhodes, Corresponding Author Christopher J. Rhodes [email protected] School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UKSchool of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK===Search for more papers by this authorTimothy C. Dintinger, Timothy C. Dintinger School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UKSearch for more papers by this authorChantal S. Hinds, Chantal S. Hinds School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UKSearch for more papers by this authorHarry Morris, Harry Morris School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UKSearch for more papers by this authorIvan D. Reid, Ivan D. Reid Muon Spectroscopy Group, Paul Scherrer Institute, CH-5232 Villigen, SwitzerlandSearch for more papers by this author Christopher J. Rhodes, Corresponding Author Christopher J. Rhodes [email protected] School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UKSchool of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK===Search for more papers by this authorTimothy C. Dintinger, Timothy C. Dintinger School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UKSearch for more papers by this authorChantal S. Hinds, Chantal S. Hinds School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UKSearch for more papers by this authorHarry Morris, Harry Morris School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UKSearch for more papers by this authorIvan D. Reid, Ivan D. Reid Muon Spectroscopy Group, Paul Scherrer Institute, CH-5232 Villigen, SwitzerlandSearch for more papers by this author First published: 13 June 2000 https://doi.org/10.1002/1097-458X(200006)38:13<::AID-MRC698>3.0.CO;2-NCitations: 9AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract Thiyl radicals (RS·) are formed labelled with muonium atoms (a radioisotope of hydrogen with a positive muon as the nucleus) and detected using the muon spin rotation (MuSR) method. This approach is shown to be extremely effective in the study of thiyl radicals, in non-aqueous (membrane-like) environments, from which details of the structures of these reactive free radicals and their reaction kinetics were determined. In this regard, the method is superior to conventional ESR spectroscopy, to which thiyl radicals are undetectable in liquid solution, and to pulse-radiolysis experiments, which are limited to aqueous media; the rate constants for the reactions of thiyl radicals with lipids but also with antioxidants such as β-carotene and (SH)glutathione are found to be enhanced in non-aqueous media. Copyright © 2000 John Wiley & Sons, Ltd. REFERENCES 1Kalyanaraman B. Biochem. Soc. Symp. 1995; 61: 55. 2Halliwell B, Gutteridge JMC. Free Radicals in Biology and Medi-cine. Clarendon Press: Oxford, 1989. 3Everett SA, Dennis MF, Patel KB, Maddix S, Kundu SC, Willson RL. J. Biol. Chem. 1996; 271: 3988. 4Mile B, Rowlands CC, Sillman PD, Fildes M. J. Chem. Soc., Perkin Trans. 2 1992; 1431. 5Nelson DJ, Petersen RL, Symons MCR. J. Chem. Soc., Perkin Trans. 2 1977; 2005. 6Symons MCR. J. Chem. Soc., Perkin Trans. 2 1974; 1618. 7Hadley JH, Gordy W. Proc. Natl. Acad. Sci. USA 1974; 71: 3106. 8Roduner E. The Positive Muon as a Probe in Free Radical Chemistry. Springer Berlin, 1988. 9Walker DC. Muon and Muonium Chemistry. Cambridge University Press: Cambridge, 1983. 10Stewart JJP. J. Comput. Chem. 1989; 10: 209, 221. 11Rhodes CJ, Roduner E, Symons MCR. J. Chem. Soc., Chem. Commun. 1988; 3. 12Kochi JK. Adv. Free Rad. Chem. 1975; 5: 304. 13Heller C, McConnell HM. J. Chem. Phys. 1960; 32: 1535. 14Fossey J, Lefort D, Sorba D. Free Radicals in Organic Chemistry. Wiley: Chilchester, 1995. 15Schoneich C, Asmus K-D, Dillinger U, Bruchhausen Fv. Biochem. Biophys. Res. Commun. 1989; 161: 113. 16McGinley L. Wall Street J. 1996; B6; Rowe PM. Lancet 1996; 347: 249. Citing Literature Volume38, Issue13Special Issue: Muon Magnetic ResonanceJune 2000Pages S49-S57 ReferencesRelatedInformation

An electron energy analyser has been designed using the concept of the 'fountain spectrometer' and the 30 degrees plane electrostatic field configuration. The advantages of the design are that measurements at a number of scattering angles from 0 to 120 degrees can be made simultaneously. The performance of the analyser is illustrated by measurements of the electron distributions from H+ on He collisions, which show the processes of charge exchange into the continuum and autoionisation of the doubly excited He atom.

This guide to class differences in Britain today is based on the latest statistical information. It reveals the distribution of wealth and income, the varieties of education, work and leisure activities, peoples' political and religious beliefs, patterns of marriage and structures of households. Ivan Reid is the author of several books including Sociology of School and Education.

The Front End Driver (FED) is a 9U 400mm VME64x card designed for reading out the CMS silicon tracker signals transmitted by the APV25 analogue pipeline ASICs. The signals are transmitted to each FED via 96 optical fibers at a total input rate corresponding to 3 Gbytes/s. The FED digitizes the signals and processes the data digitally by applying algorithms for pedestal and common mode noise subtraction. The input data rate is reduced using algorithms that search for clusters of hits. Only the cluster data along with trigger information of the event are transmitted to the CMS DAQ system using the SLINK-64 protocol at a maximum rate of 640 Mbytes/s. All data processing algorithms on the FED are executed in large on-board Field Programmable Gate Arrays (FPGA). Two FED cards have been manufactured during the last quarter of 2002. Results on the performance of the FED are presented and discussed.

Education Action Zones (EAZs) were launched in the United Kingdom in 1998 as 'the standard bearers in a new crusade … to modernize education in areas of social deprivation, and hailed as a third way in education.' In the light of the authors ' ongoing evaluation of a single EAZ, the article examines the extent to which the ambitious claims made by government have been realised. It assesses the extent to which EAZs can be viewed as part of the British twentieth-century theme in education of tackling inequality. It demonstrates that EAZ policy was riddled with tensions and paradoxes arising out of the eccentric mix of neo-liberal, social democratic and Third Way approaches to addressing educational inequality. The article concludes that EAZs suffered from three types of error: concept, process and outcomes, and hence were a mission impossible. The authors argue that EAZs may, hopefully, be a lesson in making the vision of resolving education inequality possible.

Abstract The 2,4,6‐trimethyl cyclohexadienyl radical adsorbed on a fully hydroxylated silica surface was investigated using the time‐differential and time‐integrated muon spin resonance techniques near avoided crossings of magnetic energy levels in high longitudinal magnetic fields. Information about surface diffusion is obtained from the relaxation resulting from the partial averaging of the hyperfine anisotropy when the adsorbed species diffuses over the surface of a sphere. A Redfield formalism is developed to analyse the stochastic motion in terms of diffusion coefficients. The results agree with those of a stochastic Liouville approach reported previously. Diffusion of the trimethyl‐substituted radical is described by the same Arrhenius frequency factor but a considerably higher activation energy than that of the unsubstituted analogue.

Muonium atom addition to cyclopent-4-ene-1,3-dione I leads to the adduct radical II; in contrast with all other muonium adducts of carbonyl (CO) compounds so far studied, in which the isotropic muon coupling is of positive sign, the temperature dependence of the muon coupling in II reveals that its sign is negative; this may be explained as a consequence of the electronic ‘push–pull’ interaction within the MuO–C–CC–CO system, which reduces the out-of-plane vibrational amplitude of the muon by increasing the MuO–C/MuOC partial π-bond character.

Following the recent suggestion that oxidative damage to lipids might involve the formation of C-2 glyceryl radicals, in addition to main-chain allylic radicals, which are generally thought important, we studied the kinetics of potential ‘repair’ reactions by vitamin E and vitamin K1 (which are lipophilic and tend to locate in cell membranes) with 1,1,2-trimethylallyl and 1-acetoxyprop-2-yl radicals as models of, respectively, main-chain and glyceryl-type radicals. The second-order rate constants for the reaction between trimethylallyl radicals and vitamin E and vitamin K1 are 9.38 × 106 and 3.54 × 108 l mol−1 s−1 and those between 1-acetoxyprop-2-yl radicals and vitamin E and vitamin K1 are 1.76 × 108 and 2.03 × 106 l mol−1 s−1, respectively. The results suggest that direct scavenging of glyceryl radicals by vitamin E should be an efficient process, and of main-chain allylic radicals fairly so. Additionally, it appears that vitamin K1 can act directly as a ‘radical repair agent,’ given its relatively high reactivity with allylic radicals (four times faster than with vitamin E), so prior reduction to the quinol form may be unnecessary. Copyright © 2000 John Wiley & Sons, Ltd.

Measurements have been made of the energy and angular distributions of electrons ejected from H2, N2, 02, CO2, CH4, H20, and Ar by 50 keV protons. The angular range extends from 0 to 100* and the electron energy from 5 to 150 eV. The relative values of the distribution functions for the different gases have been established by determining the relative gas number densities in the gas jet used for the target. Finally, by using previously obtained cross sections for helium, the distributions have been normalized to give absolute differential cross sections. The measurements were made with an apparatus which uses the principle of the 30* parallel plate electro- static analyzer for energy analysis of the electrons at a number of angles simultaneously (2, 3). The number of electrons scattered into each angle and energy coordinate from the intersection of the proton beam and a fine jet of target gas was found by taking the difference between two measurements. In the first measure- ment the beam passed through the jet and through background gas which consisted almost entirely of target gas at a pressure proportional to the rate of inflow through the jet. In the second measurement the background gas pressure was raised by admitting target gas through a standard leak valve, so that the difference between the two measurements represented the electrons ejected from the jet only. The effec- tiveness of capillary arrays has been demonstrated by, for example, Steckelmacher et al. (4). This is sup- ported by calculations (2) that in our apparatus 90% of the target gas is contained within a 2-mm-diameter region at the distance from the capillary at which the beam traverses. We believe that this technique pre-

We have investigated the molecular dynamics in the nematic liquid crystal 5CB using the ALC μSR technique. Our measurements are consistent with a change in the amplitude of director fluctuations at the nematic–isotropic transition and we develop a model to describe this.

Nitroxyl radicals were formed by adding the light hydrogen isotope, muonium to the spin traps DMPO (5,5-dimethyl-1-pyrroline-N-oxide) and PBN (N-tert-butyl-alpha-phenylnitrone) sorbed as 30 wt% ethanol solutions in silica-gel; evidence is presented for a specific hydrogen-bonded interaction between the DMPO adduct and the silica surface; longitudinal-field muon spin relaxation measurements (LF-MuSRx) were performed which identified two distinct motional regimes in both samples.

Pyridinium tetra#uoroborate is a ferroelectric with a paraelectric}ferroelectric phase transition of second order, which is exceptional for multidirectional ferroelectrics. Avoided-level-crossing muon-spin resonance has been used to show that the Mu substituted aza-cyclohexadienyl radical derived from the pyridinium ions undergoes fast uniaxial rotation around the axis perpendicular to the molecular plane, conrming earlier results by Czarnecki et al. The changes in reorientational dynamics between 239 and 244 K also verify the existence of a phase transition in this range, as found by Czarnecki. Furthermore, the results give strong evidence that superimposed on the rotation there is a wobbling motion of the rotational axis which freezes in at the rst transition temperature, „ 1 238.7 K. ( 2000 Elsevier Science B.V. All rights reserved.

The nature of the elusive muonium centre in sulphur is re-examined in the light of new data on its level-crossing resonance and spin–lattice relaxation. The aim is to provide a model for the solid-state chemistry of interstitial hydrogen in this element, which is as yet unknown, as well as to solve one of the longest standing puzzles in μSR spectroscopy, namely the surprisingly strong depolarization of muons mimicking ion-implanted protons in this innocuous non-magnetic material. The paramagnetic muonium (and by inference hydrogen) centre is confirmed to have the character of a molecular radical, but with huge anisotropy at cryogenic temperatures and a striking shift of the resonance at ordinary temperatures, the hyperfine parameters appearing to collapse and vanish towards the melting point. New density-functional supercell calculations identify a number of possible structures for the defect centre, including a novel form of bond-centred muonium in a closed-ring S8Mu complex. Simulations of the spin dynamics and fits to the spectra suggest a dynamical equilibrium or chemical exchange between several configurations, with occupancy of the bond-centre site falling from unity at low cryogenic temperatures to zero near the melting point.

Variations of k-d trees represent a fundamental data structure used in Computational Geometry with numerous applications in science. For example particle track fitting in the software of the LHC experiments, and in simulations of N-body systems in the study of dynamics of interacting galaxies, particle beam physics, and molecular dynamics in biochemistry. The many-body tree methods devised by Barnes and Hutt in the 1980s and the Fast Multipole Method introduced in 1987 by Greengard and Rokhlin use variants of k-d trees to reduce the computation time upper bounds to O(n log n) and even O(n) from O(n2). We present an algorithm that uses the principle of well-separated pairs decomposition to always produce compressed trees in O(n log n) work. We present and evaluate parallel implementations for the algorithm that can take advantage of multi-core architectures.

Summary This paper reviews something of the circumstances and factors which have contributed to the development and present status of the sociology of education in teacher education in England, Wales and Northern Ireland. It reports a survey which presents, through practitioners’ eyes, the discipline's present condition and their view of its future. It contrasts the resulting picture of a demise of the discipline and the pessimism of its practitioners with the condition of the sociology of education outside teacher education. It considers some of the consequences of the decline in the discipline, brought about by a decade of dramatic changes in teacher education.

Radiolabelled free radicals were formed by the addition of muonium--a radioactive hydrogen atom with a positive muon as its nucleus--to benzene, toluene and benzaldehyde, as sorbed in porous carbon. The activation parameters associated with their reorientational motion were measured using longitudinal-field muon spin relaxation (LF-MuSRx). Two distinct sorbed fractions were detected in each sample, characterised by molecular reorientational activation energies of 5.9/25.8 kJ/mol for benzene, 2.5/5.9 kJ/mol for toluene and 2.9/11.5 kJ/mol for benzaldehyde.

S ummary . Enrolment in B.Ed. as opposed to certificate courses in a sample of 168 college of education students matched by sex, academic qualifications, and course requirements was found to be associated with high N Ach, high internalization of responsibility for success, and low internalization of responsibility for failure. Personal orientation towards achievement is suggested as a critical yet relatively unresearched variable in college course choice and selection.