1+1+2 Electromagnetic perturbations on non-vacuum LRS class II space-times: Decoupling scalar and 2-vector harmonic amplitudes

We use the covariant and gauge-invariant 1+1+2 formalism of Clarkson and Barrett \cite{Clarkson2003} to analyze electromagnetic (EM) perturbations on non-vacuum {\it locally rotationally symmetric} (LRS) class II space-times. Ultimately, we show how to derive six real decoupled equations governing the total of six EM scalar and 2-vector harmonic amplitudes. Four of these are new, and result from expanding the complex EM 2-vector which we defined in \cite{Burston2007} in terms of EM 2-vector harmonic amplitudes. We are then able to show that there are four precise combinations of the amplitudes that decouple, two of these are polar perturbations whereas the remaining two are axial. The remaining two decoupled equations are the generalized Regge-Wheeler equations which were developed previously in \cite{Betschart2004}, and these govern the two EM scalar harmonic amplitudes. However, our analysis generalizes this by including a full description and classification of energy-momentum sources, such as charges and currents.Comment: 9 page

1+1+2 Electromagnetic perturbations on general LRS space-times: Regge-Wheeler and Bardeen-Press equations

We use the, covariant and gauge-invariant, 1+1+2 formalism developed by Clarkson and Barrett, and develop new techniques, to decouple electromagnetic (EM) perturbations on arbitrary locally rotationally symmetric (LRS) space-times. Ultimately, we derive 3 decoupled complex equations governing 3 complex scalars. One of these is a new Regge-Wheeler (RW) equation generalized for LRS space-times, whereas the remaining two are new generalizations of the Bardeen-Press (BP) equations. This is achieved by first using linear algebra techniques to rewrite the first-order Maxwell equations in a new complex 1+1+2 form which is conducive to decoupling. This new complex system immediately yields the generalized RW equation, and furthermore, we also derive a decoupled equation governing a newly defined complex EM 2-vector. Subsequently, a further decomposition of the 1+1+2 formalism into a 1+1+1+1 formalism is developed, allowing us to decompose the complex EM 2-vector, and its governing equations, into spin-weighted scalars, giving rise to the generalized BP equations

‘A flying start’: Wildlife trypanosomes in tissues of Australian tabanids (Diptera: Tabanidae)

Tabanids (syn. horse flies) are biting-flies of medical and veterinary significance because of their ability to transmit a range of pathogens including trypanosomes – some species of which carry a combined health and biosecurity risk. Invertebrate vectors responsible for transmitting species of Trypanosoma between Australian wildlife remains unknown, thus establishing the role of potential vector candidates such as tabanids is of utmost importance. The current study aimed to investigate the presence of indigenous trypanosomes in tabanids from an endemic area of south-west Australia. A total of 148 tabanids were collected, with morphological analysis revealing two subgenera: Scaptia (Pseudoscione) and S. (Scaptia) among collected flies. A parasitological survey using an HRM-qPCR and sequencing approach revealed a high (105/148; 71%) prevalence of trypanosomatid DNA within collected tabanids. Individual tissues - proboscis (labrum, labium and mandibles, hypopharynx), salivary glands, proventriculus, midgut, and hindgut and rectum - were also tested from a subset of 20 tabanids (n = 140 tissues), confirming the presence of Trypanosoma noyesi in 31% of screened tissues, accompanied by T. copemani (3%) and T. vegrandis/T.gilletti (5%). An unconfirmed trypanosomatid sp. was also detected (9%) within tissues. The difference between tissues infected with T. noyesi compared with tissues infected with other trypanosome species was statistically significant (p < 0.05), revealing T. noyesi as the more frequent species detected in the tabanids examined. Fluorescence in situ hybridisation (FISH) and scanning electron microscopy (SEM) confirmed intact parasites within salivary glands and the proboscis respectively, suggesting that both biological and mechanical modes of transmission could occur. This study reveals the presence of Australian Trypanosoma across tabanid tissues and confirms intact parasites within tabanid salivary glands and the proboscis for the first time. Further investigations are required to determine whether tabanids have the vectorial competence to transmit Australian trypanosomes between wildlife

Activation by sub-stoichiometric inhibition

Startling reports described the paradoxical triggering of the human mitogen-activated protein kinase pathway when a small-molecule inhibitor specifically inactivates the BRAF V600E protein kinase but not wt-BRAF. We performed a conceptual analysis of the general phenomenon "activation by inhibition" using bacterial and human HtrA proteases as models. Our data suggest a clear explanation that is based on the classic biochemical principles of allostery and cooperativity. Although substoichiometric occupancy of inhibitor binding sites results in partial inhibition, this effect is overrun by a concomitant activation of unliganded binding sites. Therefore, when an inhibitor of a cooperative enzyme does not reach saturating levels, a common scenario during drug administration, it may cause the contrary of the desired effect. The implications for drug development are discussed

The contribution of spinal glial cells to chronic pain behaviour in the monosodium iodoacetate model of osteoarthritic pain

<p>Abstract</p> <p>Background</p> <p>Clinical studies of osteoarthritis (OA) suggest central sensitization may contribute to the chronic pain experienced. This preclinical study used the monosodium iodoacetate (MIA) model of OA joint pain to investigate the potential contribution of spinal sensitization, in particular spinal glial cell activation, to pain behaviour in this model. Experimental OA was induced in the rat by the intra-articular injection of MIA and pain behaviour (change in weight bearing and distal allodynia) was assessed. Spinal cord microglia (Iba1 staining) and astrocyte (GFAP immunofluorescence) activation were measured at 7, 14 and 28 days post MIA-treatment. The effects of two known inhibitors of glial activation, nimesulide and minocycline, on pain behaviour and activation of microglia and astrocytes were assessed.</p> <p>Results</p> <p>Seven days following intra-articular injection of MIA, microglia in the ipsilateral spinal cord were activated (p < 0.05, compared to contralateral levels and compared to saline controls). Levels of activated microglia were significantly elevated at day 14 and 21 post MIA-injection. At day 28, microglia activation was significantly correlated with distal allodynia (p < 0.05). Ipsilateral spinal GFAP immunofluorescence was significantly (p < 0.01) increased at day 28, but not at earlier timepoints, in the MIA model, compared to saline controls. Repeated oral dosing (days 14-20) with nimesulide attenuated pain behaviour and the activation of microglia in the ipsilateral spinal cord at day 21. This dosing regimen also significantly attenuated distal allodynia (p < 0.001) and numbers of activated microglia (p < 0.05) and GFAP immunofluorescence (p < 0.001) one week later in MIA-treated rats, compared to vehicle-treated rats. Repeated administration of minocycline also significantly attenuated pain behaviour and reduced the number of activated microglia and decreased GFAP immunofluorescence in ipsilateral spinal cord of MIA treated rats.</p> <p>Conclusions</p> <p>Here we provide evidence for a contribution of spinal glial cells to pain behaviour, in particular distal allodynia, in this model of osteoarthritic pain. Our data suggest there is a potential role of glial cells in the central sensitization associated with OA, which may provide a novel analgesic target for the treatment of OA pain.</p

Designs for Heritage Language Learning: A Photography project in the UK Supplementary Education

Supplementary Schools in the UK offer educational opportunities for children and young people outside mainstream school provision. The paper reports an enquiry undertaken by practitioners in Greek Supplementary Schools in the UK to explore how features of mobile technologies may be leveraged to foster heritage language learning. It draws on the view that mobile learning can be a way for learners to explore the language informally and direct their own development (Kukulska-Hulme, 2015) and may also shape the learners’ ‘habits of mind’ (Wong, 2012, p.22) in learning—and consequently their language competencies. The project #ItsAllGreekToUS set to investigate how to create learning designs to incorporate effective use of mobile technologies within language learning and teaching. It draws on action research orientation and uses the idea of ‘Bring Your Own Device’ (BYOD) (JISC, 2013) in educational settings. The study involved several sessions around the concept of ‘loanwords’ and representations of this vocabulary in artefacts created with the use of mobile phones and a popular photography application (e.g. Pinterest). The participants were fourteen students (12-13s) attending a pre-GCSE class in a Greek School in London and nine students (12-14s) attending a GCSE class in a Greek School in Leicester. Evidence from user-generated content, the pupils’ views around the project and the practitioners’ observations are considered. The paper will discuss how students’ practices associated with mobile technologies are integrated into teachers’ practice. Particular attention will be drawn to designing language learning by blending traditional language classroom practices along incorporating the practices of sharing and curating content, as well as allowing ‘visibility’ through artefacts created by the learners

Reconciling the perspective of practitioner and service user: Findings from the Aphasia in Scotland study

Background: It is widely accepted that service users should be actively involved in new service developments, but there remain issues about how best to consult with them and how to reconcile their views with those of service providers. Aims: This paper uses data from The Aphasia in Scotland study, set up by NHS Quality Improvement Scotland to identify the direction of the development of services for people with aphasia in Scotland. It examines the views both of those who provide and of those who receive those services.Methods & Procedures: The study integrated findings from a questionnaire to all speech and language therapists treating people with aphasia across Scotland with findings from focus groups with service users and aphasia practitioners. Outcomes & Results: Three themes were identified: (1) public and professional awareness of the impact of aphasia on the individual and their family; (2) current service provision and gaps in services; and (3) directions for the future development of services and barriers to change. Although the impact of aphasia is well recognized amongst most professionals (that is, not just speech and language therapists), considerable concern was expressed about the level of knowledge amongst professionals who do not specialize in stroke care and about public awareness of aphasia. Service providers indicated a shift in the model of service delivery of which the service users were largely unaware. Although the majority of speech and language therapists spend most of their time providing one-to-one therapy, and this is valued by service users, there is undoubtedly an emerging shift towards a focus on broader social function and the inclusion of the person with aphasia in supportive social networks. This creates tensions because of the existing pressure for individualized models of delivery. Concern was expressed by practitioners, although not echoed by patients, about the transition from the acute sector to primary care. Practitioners also expressed concern about the introduction of more recent services like NHS 24 and e-health initiatives, which rely on means of communication that may be particularly challenging for people with aphasia. Conclusions & Implications: The findings from this study indicate that although there are clearly common perspectives, the views of people with aphasia about services do not necessarily coincide with those of service providers. This is an important consideration when initiating consultation and highlights the need for clarity on the part of practitioners in identifying the aims and objectives of their ervices as far as people with aphasia are concerned. 2010 Royal College of Speech & Language Therapists.CIHR45pub184

Covariant perturbations of f(R) black holes: the Weyl terms

In this paper we revisit non-spherical perturbations of the Schwarzschild black hole in the context of f(R) gravity. Previous studies were able to demonstrate the stability of the f(R) Schwarzschild black hole against gravitational perturbations in both the even and odd parity sectors. In particular, it was seen that the Regge-Wheeler and Zerilli equations in f(R) gravity obey the same equations as their General Relativity counterparts. More recently, the 1+1+2 semi-tetrad formalism has been used to derive a set of two wave equations: one for transverse, trace-free (tensor) perturbations and one for the additional scalar modes that characterise fourth-order theories of gravitation. The master variable governing tensor perturbations was shown to be a modified Regge-Wheeler tensor obeying the same equation as in General Relativity. However, it is well known that there is a non-uniqueness in the definition of the master variable. In this paper we derive a set of two perturbation variables and their concomitant wave equations that describe gravitational perturbations in a covariant and gauge invariant manner. These variables can be related to the Newman-Penrose (NP) Weyl scalars as well as the master variables from the 2+2 formalism