Electroweak Theory Without Higgs Bosons

A perturbative SU(2)_L X U(1)_Y electroweak theory containing W, Z, photon, ghost, lepton and quark fields, but no Higgs or other fields, gives masses to W, Z and the non-neutrino fermions by means of an unconventional choice for the unperturbed Lagrangian and a novel method of renormalisation. The renormalisation extends to all orders. The masses emerge on renormalisation to one loop. To one loop the neutrinos are massless, the A -> Z transition drops out of the theory, the d quark is unstable and S-matrix elements are independent of the gauge parameter xi.Comment: 27 pages, LaTex, no figures; revised for publication; accepted by Int. J. Mod. Phys. A; includes biographical note on A. F. Nicholso

Substitution in a sense

The Reference Principle (RP) states that co-referring expressions are everywhere intersubstitutable salva congruitate. On first glance, (RP) looks like a truism, but a truism with some bite: (RP) transforms difficult philosophical questions about co-reference into easy grammatical questions about substitutability. This has led a number of philosophers to think that we can use (RP) to make short work of certain longstanding metaphysical debates. For example, it has been suggested that all we need to do to show that the predicate ‘( ) is a horse’ does not refer to a property is point out that ‘( ) is a horse’ and ‘the property of being a horse’ are not everywhere intersubstitutable salva congruitate. However, when we understand ‘substitution’ in the simplest and most straightforward way, (RP) is no truism; in fact, natural languages are full of counterexamples to the principle. In this paper, I introduce a new notion of substitution, and then develop and argue for a version of (RP) that is immune to these counterexamples. Along the way I touch on the following topics: the relation between argument forms and their natural language instances; the reification of sense; the difference between terms and predicates; and the relation between reference and disquotation. I end by arguing that my new version of (RP) cannot be used to settle metaphysical debates quite as easily as some philosophers would like

Mapping the extent and spread of multiple plant invasions can help prioritise management in Galapagos National Park

Mapping is an important tool for the management of plant invasions. If landscapes are mapped in an appropriate way, results can help managers decide when and where to prioritize their efforts. We mapped vegetation with the aim of providing key information for managers on the extent, density and rates of spread of multiple invasive species across the landscape. Our case study focused on an area of Galapagos National Park that is faced with the challenge of managing multiple plant invasions. We used satellite imagery to produce a spatially-explicit database of plant species densities in the canopy, finding that 92% of the humid highlands had some degree of invasion and 41% of the canopy was comprised of invasive plants. We also calculated the rate of spread of eight invasive species using known introduction dates, finding that species with the most limited dispersal ability had the slowest spread rates while those able to disperse long distances had a range of spread rates. Our results on spread rate fall at the lower end of the range of published spread rates of invasive plants. This is probably because most studies are based on the entire geographic extent, whereas our estimates took plant density into account. A spatial database of plant species densities, such as the one developed in our case study, can be used by managers to decide where to apply management actions and thereby help curtail the spread of current plant invasions. For example, it can be used to identify sites containing several invasive plant species, to find the density of a particular species across the landscape or to locate where native species make up the majority of the canopy. Similar databases could be developed elsewhere to help inform the management of multiple plant invasions over the landscape

Locations of marine animals revealed by carbon isotopes

Knowing the distribution of marine animals is central to understanding climatic and other environmental influences on population ecology. This information has proven difficult to gain through capture-based methods biased by capture location. Here we show that marine location can be inferred from animal tissues. As the carbon isotope composition of animal tissues varies with sea surface temperature, marine location can be identified by matching time series of carbon isotopes measured in tissues to sea surface temperature records. Applying this technique to populations of Atlantic salmon (Salmo salar L.) produces isotopically-derived maps of oceanic feeding grounds, consistent with the current understanding of salmon migrations, that additionally reveal geographic segregation in feeding grounds between individual philopatric populations and age-classes. Carbon isotope ratios can be used to identify the location of open ocean feeding grounds for any pelagic animals for which tissue archives and matching records of sea surface temperature are available

Outsourcing the nation-state : a rational choice framework for the provision of public goods

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Ketamine treatment for individuals with treatment-resistant depression: a longitudinal qualitative interview study of patient experiences

Background Ketamine has recently received considerable attention regarding its antidepressant and anti-suicidal effects. Trials have generally focused on short-term effects of single intravenous infusions. Research on patient experiences is lacking. Aims To investigate the experiences over time of individuals receiving ketamine treatment in a routine clinic, including impacts on mood and suicidality. Method Twelve fee-paying patients with treatment-resistant depression (6 females, 6 males, age 21-70 years; 11 reporting suicidality and six self-harm) who were assessed as eligible for ketamine treatment participated in up to three semi-structured interviews: before treatment started, a few weeks into treatment and two or more months later. Data were analysed thematically. Results Most participants hoped that ketamine would provide respite from their depression. All experienced improvement in mood following initial treatments, ranging from negligible to dramatic, and eight a reduction in suicidality. Improvements were transitory for most participants, although two experienced sustained consistent benefit and two had sustained but limited improvement. Some participants described hopelessness when treatment stopped working, paralleled by increased suicidal ideation for three. The transient nature and cost of treatment were problematic. Eleven participants experienced side-effects, which in two cases were significant. Suggestions for improving treatment included closer monitoring and adjunctive psychological therapy. Conclusions Ketamine treatment was generally experienced as effective in improving mood and reducing suicidal ideation in the short-term, but the lack of longer-term benefit was challenging for participants, as was treatment cost. Informed consent procedures should refer to the possibilities of relapse and of associated increased hopelessness and suicidality

Anomalous amplitudes in a thermal bath

I review the implications of the axial anomaly in a thermal bath. I assume that the Adler-Bardeen theorem applies at nonzero temperature, so that the divergence of the axial current remains is independent of temperature. Nevertheless, I argue that while the anomaly doesn't change with temperature, ``anomalous'' mesonic couplings do. This is verified by explicit calculations in a low temperature expansion, and near the chiral phase transition.Comment: 11 pages, PTPTeX, to appear in the Proceedings of YKIS '9

Effects of ketamine treatment on suicidal ideation: a qualitative study of patients’ accounts following treatment for depression in a UK ketamine clinic

Objective It is recognised that ketamine treatment can reduce suicidal ideation (SI) in people with depression, at least in the short term. However, information is lacking on patients’ perspectives on such effects. Studying these can contribute to greater understanding of the mechanisms underlying impact of ketamine treatment on SI. The aim of this study was to investigate patients’ reports of the impact of treatment on their SI, the duration of effects and possible mechanisms. Design and setting This qualitative study consisted of semi-structured interviews with patients who had received ketamine treatment for depression. Interview data were analysed thematically. Participants Fourteen patients (8 females, 6 males, aged 24–64 years) who had received treatment with ketamine for treatment-resistant depression, and had SI at the initiation of treatment. Two participants also had a diagnosis of bipolar type 1 and two of emotionally unstable personality disorder. Eight had a history of self-harm. Results SI reduced following ketamine treatment in 12 out of 14 participants for periods of a few hours following a single treatment to up to three years with ongoing treatment. Reduction of SI was variable in terms of extent and duration, and re-emergence of suicidal thoughts often occurred when treatment ceased. Participants’ accounts indicated that reduced SI was associated with improved mood and reduced anxiety, as were clarity of thought, focus and concentration, and ability to function. Participants reported experiencing some or all of these effects in various orders of occurrence. Conclusion Generally, ketamine treatment was experienced as effective in reducing SI, although duration of effects varied considerably. Patients’ perspectives indicated similarities in the mechanisms of reduction in SI, but some differences in their manifestation, particularly in relation to chronology. Experiences of this cohort suggest that reduced anxiety and improvement in ability to think and function were important mechanisms alongside, or in some cases independently of, improvement in mood. Further studies of patients’ experiences are required to gain enhanced understanding of the variability of effects of ketamine on SI and functionality

Book Reviews

The following publications have been reviewed by the authors;That's Nice! - reviewed by Ian McLintockWorkshop Electrics - reviewed by Alan TruemanCommunicating Design - reviewed by R. FoulgerEngineering Design Methods - reviewed by Chris SnellTechnopacks  - reviewed by Elsie Warre