4,842 research outputs found

    E6 Models from F-theory

    Full text link
    F-theory is a non-perturbative formulation of type IIB superstring theory which allows for the decoupling of gravity and for the formulation of GUT theories based on the gauge group E6. In this paper we explore F-theory models in which the low energy supersymmetric theory contains the particle content of three 27 dimensional representations of the underlying E6 gauge group, plus two extra right-handed neutrinos predicted from F and D flatness. The resulting TeV scale effective theory resembles either the E6SSM or the NMSSM+, depending on whether an additional Abelian gauge group does or does not survive. However there are novel features compared to both these models as follows: (i) If the additional Abelian gauge group is unbroken then it can have a weaker gauge coupling than in the E6SSM; (ii) If the additional Abelian gauge group is broken then non-perturbative effects can violate the scale invariance of the NMSSM+ leading to a generalised model; (iii) Unification is achieved not at the field theory level but at the F-theory level since the gauge couplings are split by flux effects, negating the need for any additional doublet states which are usually required; (iv) Proton decay is suppressed by the geometric coupling suppression of a singlet state, a mechanism peculiar to F-theory, which effectively suppresses the coupling of the exotic charge -1/3 colour triplet state D to quarks and leptons; (v) The D bar couples to left-handed leptoquarks, providing characteristic and striking signatures at the LHC.Comment: 31 pages, 7 figure

    A Review of the Nurse Consultant Role

    Get PDF
    Background This paper reports the results of a review of the Nurse Consultant role at Nottinghamshire Healthcare NHS Trust the aim of which was to provide a clear picture of the current role remit and impact of each Nurse Consultant to inform recommendations for [any] required revision and ensure that Nurse Consultant’s roles and responsibilities are aligned to the evidence on best practice, reflect the Trusts business priorities, and that there is a well understood model in operation. Methods Using multiple methods of data collection, we investigated perceptions of the impact of Nurse Consultants among general managers and clinical directors, service users and carers, and selected other colleagues using semi-structured interviews and a focus group, as well as exploring with Nurse Consultants their view of the impact of their role via semi-structured interviews. In addition, we evaluated the leadership skills of Nurse Consultants using a 360 degree evaluation. Finally, we examined the activities of Nurse Consultants by analysing their diaries during a three month period. Results Nurse Consultants spend 38% of their activity on expert practice, 26% on professional leadership and practice, 19% on education, training and supervision and 15% on practice development, research and evaluation; 2% is spent on other activities. On the 360 degree evaluations, Nurse Consultants scored highest on enabling others (median 52/60), followed by modelling, encouraging and inspiring others (51/60). They scored lowest on challenging others (47/60). General Managers and Clinical Directors reported the positive impact Nurse Consultants have on clinical leadership and their contribution to improving clinical strategies and service developments. Service users and carers reported that they value the role, but were critical of the absence of Nurse Consultants in acute mental health wards. Conclusions The practices of Nurse Consultants at Nottinghamshire Healthcare Trust reflect the suggested domains of the role, but they fall short of national expectations of the percentage time NC should spend on expert clinical practice. There is widespread recognition of the positive impact of the role on service development and evidence of the positive impact of Nurse Consultants on practice. In general, colleagues recognise that Nurse Consultants are positive role models, who inspire, challenge, encourage and enable others. There is a widespread belief in the untapped potential for Nurse Consultants to play a more strategic leadership role in the Trust. Recommendations are made for the future development of the Nurse Consultant role

    Intrinsic antecedents of academic research productivity of a large South African university

    Get PDF
    Across different contexts, the human resources literature suggests that a range of intrinsic factors – typically measured as psychographic, or intrinsic, variables – are antecedents of individual job performance. What is not clear from this literature, however, is the relative contribution of different dimensions of these factors to research output as a measure of individual job performance in the South African academic context. This research seeks to address this lack of knowledge. A large South African university was comprehensively sampled. Structural equation modelling was used to test a model of these relationships predicted by this body of theory. The fi ndings contest certain predictions of seminal theory. This context is found to potentially be atypical of other work contexts. It is argued that certain theory and research fi ndings might not all necessarily generalise into this context because (i) research productivity as a form of job performance may differ from other forms of job performance, and (ii) a cohort of academics may differ from other professional cohorts in other contexts. New insights into the antecedents of research productivity in this context are offered, and recommendations are made for how academics might increase their research productivity.Key words: job performance, South Africa, research productivity, human resources managemen

    Gauge Coupling Unification in E6 F-Theory GUTs with Matter and Bulk Exotics from Flux Breaking

    Full text link
    We consider gauge coupling unification in E6 F-Theory Grand Unified Theories (GUTs) where E6 is broken to the Standard Model (SM) gauge group using fluxes. In such models there are two types of exotics that can affect gauge coupling unification, namely matter exotics from the matter curves in the 27 dimensional representation of E6 and the bulk exotics from the adjoint 78 dimensional representation of E6. We explore the conditions required for either the complete or partial removal of bulk exotics from the low energy spectrum. In the latter case we shall show that (miraculously) gauge coupling unification may be possible even if there are bulk exotics at the TeV scale. Indeed in some cases it is necessary for bulk exotics to survive to the TeV scale in order to cancel the effects coming from other TeV scale matter exotics which would by themselves spoil gauge coupling unification. The combination of matter and bulk exotics in these cases can lead to precise gauge coupling unification which would not be possible with either type of exotics considered by themselves. The combination of matter and bulk exotics at the TeV scale represents a unique and striking signature of E6 F-theory GUTs that can be tested at the LHC.Comment: 21 pages, 5 figure

    A causal elimination of ordinary objects : do baseballs shatter windows?

    Get PDF

    Investigation of Noise Field and Velocity Profiles of an Afterburning Engine

    Get PDF
    Sound pressure levels, frequency spectrum, and jet velocity profiles are presented for an engine-afterburner combination at various values of afterburner fuel - air ratio. At the high fuel-air ratios, severe low-frequency resonance was encountered which represented more than half the total energy in the sound spectrum. At similar thrust conditions, lower sound pressure levels were obtained from a current fighter air craft with a different afterburner configuration. The lower sound pressure levels are attributed to resonance-free afterburner operation and thereby indicate the importance of acoustic considerations in afterburner design

    A Week Can be a Long Time in Mental Illness

    Get PDF
    An erosion of the Mental Health Act is worrying. The safeguards on our human rights hang by a slender thread. In July last year, everyone in NSW had one such safeguard cut away. Its removal, by a simple bureaucratic manoeuvre, will be hard felt by anyone unfortunate enough to become severely mentally ill. Mental illness can happen to anyone. Severe depression, for example, affects one person in 10 and can strike at any age. The NSW Mental Health Act gives psychiatrists extraordinary powers to lock up and medicate people with severe mental illness, even when the affected person refuses all treatment. These powers are important. They can and do save lives. But, like any extraordinary power, there is always a risk that they might be abused. To make abuse less likely the Mental Health Act only allows a person to be held on a psychiatrist's order for a very short time and demands that the order be quickly and automatically reviewed by an independent tribunal. How quickly? The phrase in the Act is "as soon as practicable". Until July last year "as soon as practicable" was interpreted as within about a week - usually within a few days. Of course, many felt that even a few days was a long time, if you were in a psychiatric hospital and believed you shouldn't be there. However, most people accepted that within about a week was a pretty reasonable definition for "as soon as practicable". It was the definition used for more than 50 years and the system seemed to work very well. In July last year though, everything changed. The Mental Health Review Tribunal took over the independent reviews from magistrates, and the president of the Tribunal, Greg James, advised hospitals that although the Act said that these reviews should happen "as soon as practicable", in some cases people should be made to wait in detention for at least two weeks before their automatic review

    A Week Can be a Long Time in Mental Illness

    Get PDF
    An erosion of the Mental Health Act is worrying. The safeguards on our human rights hang by a slender thread. In July last year, everyone in NSW had one such safeguard cut away. Its removal, by a simple bureaucratic manoeuvre, will be hard felt by anyone unfortunate enough to become severely mentally ill. Mental illness can happen to anyone. Severe depression, for example, affects one person in 10 and can strike at any age. The NSW Mental Health Act gives psychiatrists extraordinary powers to lock up and medicate people with severe mental illness, even when the affected person refuses all treatment. These powers are important. They can and do save lives. But, like any extraordinary power, there is always a risk that they might be abused. To make abuse less likely the Mental Health Act only allows a person to be held on a psychiatrist's order for a very short time and demands that the order be quickly and automatically reviewed by an independent tribunal. How quickly? The phrase in the Act is "as soon as practicable". Until July last year "as soon as practicable" was interpreted as within about a week - usually within a few days. Of course, many felt that even a few days was a long time, if you were in a psychiatric hospital and believed you shouldn't be there. However, most people accepted that within about a week was a pretty reasonable definition for "as soon as practicable". It was the definition used for more than 50 years and the system seemed to work very well. In July last year though, everything changed. The Mental Health Review Tribunal took over the independent reviews from magistrates, and the president of the Tribunal, Greg James, advised hospitals that although the Act said that these reviews should happen "as soon as practicable", in some cases people should be made to wait in detention for at least two weeks before their automatic review
    • …
    corecore