Exact spinor-scalar bound states in a QFT with scalar interactions

We study two-particle systems in a model quantum field theory, in which scalar particles and spinor particles interact via a mediating scalar field. The Lagrangian of the model is reformulated by using covariant Green's functions to solve for the mediating field in terms of the particle fields. This results in a Hamiltonian in which the mediating-field propagator appears directly in the interaction term. It is shown that exact two-particle eigenstates of the Hamiltonian can be determined. The resulting relativistic fermion-boson equation is shown to have Dirac and Klein-Gordon one-particle limits. Analytic solutions for the bound state energy spectrum are obtained for the case of massless mediating fields.Comment: 12 pages, RevTeX, 1 figur

Hole-mediated photoredox catalysis: Tris(: P-substituted)biarylaminium radical cations as tunable, precomplexing and potent photooxidants

As a combination of visible light photoredox catalysis and synthetic organic electrochemistry, electrochemically-mediated photoredox catalysis emerged as a powerful synthetic technique in recent years, overcoming fundamental limitations of electrochemistry and photoredox catalysis in the single electron transfer activation of small organic molecules. Herein we report a tunable class of electroactivated photoredox catalyst, tri(para-substituted)biarylamines, that become superoxidants in their photoexcited states even able to oxidize molecules beyond the solvent window limits of cyclic voltammetry (such as polyfluorobenzene and trifluorotoluene). Furthermore, we demonstrate that precomplexation not only permits the excited state photochemistry of tris(para-substituted)biarylaminium cations to overcome picosecond lifetime, but enables and rationalizes the surprising photochemistry of their higher-order doublet (Dn) excited states, unlocking extremely high oxidative potentials (up to a record-breaking ∼+4.4 V vs. SCE). This journal i

KOtBu : a privileged reagent for electron transfer reactions?

Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive. These reaction classes include coupling reactions of halobenzenes and arenes, reductive cleavages of dithianes and SRN1 reactions. Direct electron transfer would imply that alkali metal alkoxides are willing partners in these electron transfer reactions, but the literature reports provide little or no experimental evidence for this. This paper examines each of these classes of reaction in turn, and contests the roles proposed for KOtBu; instead, it provides new mechanistic information that in each case supports the in situ formation of organic electron donors. We go on to show that direct electron transfer from KOtBu can however occur in appropriate cases, where the electron acceptor has a reduction potential near the oxidation potential of KOtBu, and the example that we use is CBr4. In this case, computational results support electrochemical data in backing a direct electron transfer reaction

The effect of multiple host species on a keystone parasitic plant and its aphid herbivores

1. The exploitation of shared resources by diverse organisms underpins the structure of ecological communities. Hemiparasitic plants and the insect herbivores feeding on them both rely, directly and indirectly, on the resources supplied by the parasite's host plant. Therefore, the identity and number of host plant species providing these resources is likely to be critical for parasite and herbivore performance. 2. We tested the effect of single and multiple host species on the biomass of the generalist parasitic plant Rhinanthus minor and the abundance of its aphid (Aphis gossypii) herbivores. 3. Parasite biomass was proportional to the number of haustorial connections to host roots and was determined by host species identity rather than host functional group. Host species identity was also an important influence on aphid population size, and parasites attached to Lotus corniculatus experienced a considerable reduction in aphid herbivory. 4. The effects on the parasite attaching to multiple hosts depended on the combination of species present. However, host mixtures generally benefitted aphids by diluting the negative effects of particular host species. 5. Our findings suggest that the specificity of host attachment alters the impact of this keystone parasitic plant on its own herbivores and, potentially, on the wider plant and herbivore community

Inventory of ATT system requirements for elderly and disabled drivers and travellers

This Inventory of ATT System Requirements for Elderly and Disabled Drivers and Travellers is the product of the TELSCAN project’s Workpackage 3: Identification and Updating of User Requirements of Elderly and Disabled Travellers. It describes the methods and tools used to identify the needs of elderly and disabled (E&D) travellers. The result of this investigation is a summary of the requirements of elderly and disabled travellers using different modes of transport, including private cars, buses/trams, metros/trains, ships and airplanes. It provides a generic user requirements specification which can guide the design of all transport telematics systems. However, it is important to stress that projects should also capture a more detailed definition of user requirements for their specific application area or system

Current opinions on the management of prolonged ischemic priapism: does penoscrotal decompression outperform corporoglanular tunneling?

Prolonged ischemic priapism presents a treatment challenge given the difficulty in achieving detumescence and effects on sexual function. To evaluate current practice patterns, an open, web-based multi-institutional survey querying surgeons' experience with and perceived efficacy of tunneling maneuvers (corporoglanular tunneling and penoscrotal decompression), as well as impressions of erectile recovery, was administered to members of societies specializing in male genital surgery. Following distribution, 141 responses were received. Tunneling procedures were the favored first-line surgical intervention in the prolonged setting (99/139, 71.2% tunneling vs. 14/139, 10.1% implant, p < .001). Although respondents were more likely to have performed corporoglanular tunneling than penoscrotal decompression (124/138, 89.9% vs. 86/137, 62.8%, p < .001), penoscrotal decompression was perceived as more effective among those who had performed both (47.3% Very or Extremely Effective for penoscrotal decompression vs. 18.7% for corporoglanular tunneling; p < .001). Many respondents who had performed both tunneling procedures felt that most regained meaningful sexual function after either corporoglanular tunneling or penoscrotal decompression (33/75, 44.0% vs. 33/74, 44.6%, p = .942). While further patient-centered investigation is warranted, this study suggests that penoscrotal decompression may outperform corporoglanular tunneling for prolonged priapism, and that recovery of sexual function may be higher than previously thought after tunneling procedures

Mutual aid groups in psychiatry and substance misuse

Background: Mutuality is a feature of many ‘self-help groups’ for people with mental health and/or substance misuse needs. These groups are diverse in terms of membership, aims, organisation and resources. Collectively, in terms of the pathways for seeking help, support, social capital or simply validation as people, mutual aid groups figure at some time in the life story of many psychiatric and/or substance misuse patients. From the viewpoint of clinical services, relations with such groups range from formal collaboration, through incidental shared care, via indifference, to incomprehension, suspicion, or even hostility. How should mental health and substance misuse clinicians relate to this informal care sector, in practice? Aims: To synthesise knowledge about three aspects of the relationship between psychiatric/substance misuse services and mutual aid groups: profile groups' engagement of people with mental health and/or substance misuse needs at all stages of vulnerability, illness or recovery; characterise patterns of health benefit or harm to patients, where such outcome evidence exists; identify features of mutual aid groups that distinguish them from clinical services. Method: A search of both published and unpublished literature with a focus on reports of psychiatric and substance misuse referral routes and outcomes, compiled for meta-synthesis. Results: Negative outcomes were found occasionally, but in general mutual aid group membership was repeatedly associated with positive benefits. Conclusions: Greater awareness of this resource for mental health and substance misuse fields could enhance practice