4,179 research outputs found

    Diamonds are Forever

    Get PDF
    We defend the thesis that every necessarily true proposition is always true. Since not every proposition that is always true is necessarily true, our thesis is at odds with theories of modality and time, such as those of Kit Fine and David Kaplan, which posit a fundamental symmetry between modal and tense operators. According to such theories, just as it is a contingent matter what is true at a given time, it is likewise a temporary matter what is true at a given possible world; so a proposition that is now true at all worlds, and thus necessarily true, may yet at some past or future time be false in the actual world, and thus not always true. We reconstruct and criticize several lines of argument in favor of this picture, and then argue against the picture on the grounds that it is inconsistent with certain sorts of contingency in the structure of time

    Inflammatory or rheumatoid arthritis patients’ perspectives on the effect of arthritis gloves on their hand pain and function (A-GLOVES TRIAL) : a qualitative study

    Get PDF
    Background: Arthritis (compression) gloves are frequently provided to people with inflammatory (IA) or rheumatoid arthritis (RA) in the NHS, to help reduce swelling and alleviate hand pain by providing compression and improving circulation. However evidence for their effectiveness is limited.[1] Objectives: Nested within a randomised controlled trial (RCT) testing the effectiveness of intervention (compression) gloves with control gloves (fitted at least one size too big) in people with RA and IA, this qualitative study aimed to explore patients’ perspectives on the effect of the arthritis gloves on their hand pain and function. Methods: Once randomised, participants were provided joint protection and hand exercise booklets and fitted with either the intervention or the control glove(s) by a trained occupational therapist.[2] Both gloves had similar thermal qualities but control gloves did not apply compression. Semi-structured interviews were conducted with 10 participants, purposively selected from each group (n=20) following 12 weeks of glove wear. Interviews were audio-recorded, transcribed and analysed by three researchers using thematic analysis with a critical realist perspective. Results: Participants’ perspectives on the effects of the arthritis gloves had three emergent sub-themes. These were: Usage: both groups predominantly used the gloves for activities such as wearing them outdoors to keep hands warm, night-time wear to help with sleep, and doing light domestic activities (e.g. dusting). Gloves were not used for cooking or washing-up or for personal activities of daily living (e.g. toileting, grooming) “What didn’t help as such, obviously was with washing etc. and toileting because I had to keep taking them off and putting them back on again”; Symptomatology: while some reported that gloves helped to keep their “hand pain in check” others said that gloves had no effect on their hand pain or that they’d found “it’s made them worse”. Participants from both groups frequently mentioned the warmth element of the gloves, as a positive attribute to help with their symptoms; Aesthetics: participants had opposing views on the appearance of the arthritis gloves. Some felt that the intervention gloves “look a bit ugly with the seams outside” or stated that they “would not want to wear that colour” but did not think they were obtrusive. Most noticeably, patients seemed to view the arthritis gloves as ordinary everyday gloves, rather than a medical device “if it was cold I wore them outside”. Conclusions: Trial participants reported experiencing similar effects from wearing either the intervention or control gloves, with varied perspectives on whether or not gloves affected hand pain and/or function. Overall, patients did not reflect on the compressive but rather the thermal qualities of the gloves, as warmth was the main effect perceived. References: Hammond, et al. Clin Rehabil 2016 30:213–24 Prior, et al. Rheum 2017(Supp1) Acknowledgements: This project was funded by the NIHR Research for Patient Benefit Programme (PB-PG-0214–33010). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health

    Synthesis and antibacterial effects of cobalt–cellulose magnetic nanocomposites

    Get PDF
    © The Royal Society of Chemistry. Green synthesis is employed to prepare cobalt/cellulose nanocomposites with cubic (α-cobalt) cobalt as a main component with antibacterial and magnetic properties. An in situ reduction of aqueous solutions of cobalt ions on a model cellulose substrate surface using hydrogen gas affords spherical, cellulose-stabilised cobalt nanoclusters with magnetic properties and an average diameter of 7 nm that are distributed evenly over the surface of the cellulose fibres. These cobalt/cellulose nanocomposites exhibit good antibacterial action against opportunistic pathogens both Gram-positive (S. aureus) and Gram-negative (E. coli, A. baumannii and P. aeruginosa), with zones of inhibition up to 15 mm, thereby encouraging the deployment of these advanced materials for the treatment of wastewater or within medical dressings. This method of preparation is compared with the analogous in situ reduction of cobalt ions on a cellulose surface using sodium borohydride as reducing agent

    Mid-gut ACTH-secreting neuroendocrine tumor unmasked with (18)F-dihydroxyphenylalanine-positron emission tomography.

    Get PDF
    Ectopic ACTH Cushing's syndrome (EAS) is often caused by neuroendocrine tumors (NETs) of lungs, pancreas, thymus, and other less frequent locations. Localizing the source of ACTH can be challenging. A 64-year-old man presented with rapidly progressing fatigue, muscular weakness, and dyspnea. He was in poor condition and showed facial redness, proximal amyotrophy, and bruises. Laboratory disclosed hypokalemia, metabolic alkalosis, and markedly elevated ACTH and cortisol levels. Pituitary was normal on magnetic resonance imaging (MRI), and bilateral inferior petrosal sinus blood sampling with corticotropin-releasing hormone stimulation showed no significant central-to-periphery gradient of ACTH. Head and neck, thoracic and abdominal computerized tomography (CT), MRI, somatostatin receptor scintigraphy (SSRS), and (18)F-deoxyglucose-positron emission tomography (FDG-PET) failed to identify the primary tumor. (18)F-dihydroxyphenylalanine (F-DOPA)-PET/CT unveiled a 20-mm nodule in the jejunum and a metastatic lymph node. Segmental jejunum resection showed two adjacent NETs, measuring 2.0 and 0.5 cm with a peritoneal metastasis. The largest tumor expressed ACTH in 30% of cells. Following surgery, after a transient adrenal insufficiency, ACTH and cortisol levels returned to normal values and remain normal over a follow-up of 26 months. Small mid-gut NETs are difficult to localize on CT or MRI, and require metabolic imaging. Owing to low mitotic activity, NETs are generally poor candidates for FDG-PET, whereas SSRS shows poor sensitivity in EAS due to intrinsically low tumor concentration of type-2 somatostatin receptors (SST2) or to receptor down regulation by excess cortisol. However, F-DOPA-PET, which is related to amine precursor uptake by NETs, has been reported to have high positive predictive value for occult EAS despite low sensitivity, and constitutes a useful alternative to more conventional methods of tumor localization. LEARNING POINTS: Uncontrolled high cortisol levels in EAS can be lethal if untreated.Surgical excision is the keystone of NETs treatment, thus tumor localization is crucial.Most cases of EAS are caused by NETs, which are located mainly in the lungs. However, small gut NETs are elusive to conventional imaging and require metabolic imaging for detection.FDG-PET, based on tumor high metabolic rate, may not detect NETs that have low mitotic activity. SSRS may also fail, due to absent or low concentration of SST2, which may be down regulated by excess cortisol.F-DOPA-PET, based on amine-precursor uptake, can be a useful method to localize the occult source of ACTH in EAS when other methods have failed

    One-loop self-energy correction to the 1s and 2s hyperfine splitting in H-like systems

    Get PDF
    The one-loop self-energy correction to the hyperfine splitting of the 1s and 2s levels in H-like low-Z atoms is evaluated to all orders in Z\alpha. The results are compared to perturbative calculations. The residual higher-order contribution is evaluated. Implications to the specific difference of the hyperfine structure intervals 8\Delta \nu_2 - \Delta \nu_1 in He^+ are investigated.Comment: 17 pages, RevTeX, 3 figure

    Hennessy-Milner Logic with Greatest Fixed Points as a Complete Behavioural Specification Theory

    Get PDF
    There are two fundamentally different approaches to specifying and verifying properties of systems. The logical approach makes use of specifications given as formulae of temporal or modal logics and relies on efficient model checking algorithms; the behavioural approach exploits various equivalence or refinement checking methods, provided the specifications are given in the same formalism as implementations. In this paper we provide translations between the logical formalism of Hennessy-Milner logic with greatest fixed points and the behavioural formalism of disjunctive modal transition systems. We also introduce a new operation of quotient for the above equivalent formalisms, which is adjoint to structural composition and allows synthesis of missing specifications from partial implementations. This is a substantial generalisation of the quotient for deterministic modal transition systems defined in earlier papers

    A Monte Carlo simulation of the Sudbury Neutrino Observatory proportional counters

    Get PDF
    The third phase of the Sudbury Neutrino Observatory (SNO) experiment added an array of 3He proportional counters to the detector. The purpose of this Neutral Current Detection (NCD) array was to observe neutrons resulting from neutral-current solar neutrino-deuteron interactions. We have developed a detailed simulation of the current pulses from the NCD array proportional counters, from the primary neutron capture on 3He through the NCD array signal-processing electronics. This NCD array Monte Carlo simulation was used to model the alpha-decay background in SNO's third-phase 8B solar-neutrino measurement.Comment: 38 pages; submitted to the New Journal of Physic

    Proof-theoretic semantics, a problem with negation and prospects for modality

    Get PDF
    This paper discusses proof-theoretic semantics, the project of specifying the meanings of the logical constants in terms of rules of inference governing them. I concentrate on Michael Dummett’s and Dag Prawitz’ philosophical motivations and give precise characterisations of the crucial notions of harmony and stability, placed in the context of proving normalisation results in systems of natural deduction. I point out a problem for defining the meaning of negation in this framework and prospects for an account of the meanings of modal operators in terms of rules of inference
    corecore