1,463 research outputs found

    Gluon chain formation in presence of static charges

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    We consider the origins of the gluon chain model. The model serves as a realization of the dynamics of the chromoelectric flux between static quark-antiquark sources. The derivation is based on the large-N_C limit of the Coulomb gauge Hamiltonian in the presence of a background field introduced to model magnetic confinement.Comment: 10 pages, 9 figure

    Sudden bilateral loss of vision in a 19-year-old man

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    Introduction: Posterior Reversible Leukoencephalopathy Syndrome (PRES) is caused by ischaemia commonly affecting the posterior cerebral vasculature. It presents with sudden decreased vision, headaches, nausea, vomiting, seizures, and altered mental status. Case presentation: A 19-year-old male presented to the ophthalmic emergency complaining of sudden bilateral loss of vision, which was down to light perception He reported headaches, nausea, and drowsiness since the previous day. He was a known case of hypertension secondary to IgA nephropathy. Magnetic resonance imaging (MRI) with STIR and FLAIR sequences showed foci of hyperintensity within the occipital lobes bilaterally. This confirmed the suspected diagnosis of PRES. Discussion: Aetiological factors of PRES include sudden increase in blood pressure, eclampsia, porphyria, renal disease, and Cushing syndrome. These lead to blood-brain barrier injury either by hyper- or hypoperfusion, endothelial dysfunction, changes in blood vessel morphology, hypocapnea, or immune system activation. Histopathological changes in PRES include activated astrocytes, scattered macrophages and lymphocytes, often in the absence of inflammation or neuronal damage. Conclusion: PRES is usually a reversible neuroophthalmological condition, however prompt recognition and appropriate management is important to prevent permanent brain injury or even death.peer-reviewe

    Blepharitis

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    Blepharitis is a very common and under-appreciated eyelid margin condition which causes non-specific ocular irritation, significant patient distress. Chronic blepharitis is often difficult to manage. The true prevalence of blepharitis is difficult to estimate; figures cited in the literature range from 12%-79% due to the different ways how blepharitis may manifest itself and ill-defined diagnostic criteria.peer-reviewe

    "It's such a battle": A phenomenological account of raising a child on the autistic spectrum - a battle with bureaucracy and behaviour

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    A sharp rise in the prevalence of Autism Spectrum Disorder (ASD), has led to it becoming one of the most widely researched neurodevelopmental conditions. Although the predominant focus in autism research is child centred, research on parent outcomes has highlighted considerable impact, in terms of parent’s mental health and wellbeing. Previous studies have shown that parents of children with autism suffer extremes of distress, in excess of that of parents of children with other disabilities. However, why this is so is less understood. Interpretative phenomenological analysis was used to analyse data, gathered from semi-structured interviews of seven parents raising children diagnosed with autism. Through qualitative investigation of parents' lived experience, four main themes emerged; bureaucracy, behaviour, socio-affective impact and a child-centred focus, with bureaucracy emerging as the superordinate theme. Analysis of the data revealed two key areas underpinning parental distress; a protracted diagnostic and statement-of-education process and an absence of professional support and information to manage challenging behaviour. Suggestions for improvement were discussed, in terms of streamlining bureaucratic processes, through better awareness of autism in frontline health professionals and the provision of parent training

    Unravelling the DNA sequences carried by Streptomyces coelicolor membrane vesicles

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    Membrane vesicles (MVs) are spherical particles with nanoscale dimensions and characterized by the presence of diverse cargos, such as nucleic acids, proteins, lipids, and cellular metabolites. Many examples of (micro)organisms producing MVs are reported in literature. Among them, bacterial MVs are of particular interest because they are now considered as the fourth mechanism of horizontal gene transfer. Streptomyces bacteria are well-known for their ecological roles and ability to synthesize bioactive compounds, with Streptomyces coelicolor being the model organism. It was previously demonstrated that it can produce distinct populations of MVs characterized by different protein and metabolite cargos. In this work we demonstrated for the first time that MVs of S. coelicolor carry both DNA and RNA and that their DNA content represents the entire chromosome of the bacterium. These findings suggest that MV DNA could have a role in the evolution of Streptomyces genomes and that MVs could be exploited in new strain engineering strategies

    Can pterygium excision with mitomycin C leaving bare sclera be salvaged?

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    Purpose The aim of this study was to analyze the recurrence rate of pterygium following excision with intra-operative mitomycin C (MMC) and post-operative scraping of the perilimbal conjunctival defect, and the patients’ satisfaction with this technique. Methods This is a retrospective analysis of a cohort of 33 eyes of 28 patients with primary or recurrent pterygium who underwent simple excision with MMC. They were followed up after a mean of 27.8 months. The main outcomes considered were the recurrence rate and patient satisfaction. A recurrence was defined as any regrowth of conjunctiva over the limbus and any complications were considered significant. The patients were interviewed with a standard questionnaire and examined. Results An objective recurrence was noted in 55% (18 out of 33 eyes). The recurrence rate after excision of primary pterygia was 46% (13 out of 28 eyes), and for recurrent pterygia it was 80% (four out of five eyes). In this study the complications included: six eyes that developed a granuloma, one case of bleeding which persisted for three days post-op, and one eye in which there was a suspected scleral melt at five weeks. 79% of the procedures resulted in a good patient satisfaction (26 out of 33 eyes), and only in 15% (five eyes) was there a subjective recurrence. Conclusions This technique in our study resulted in an unacceptably high recurrence rate, especially in the case of recurrent pterygia. However patients still tended to be satisfied with the outcome.peer-reviewe

    CUMAS: a seafloor multi-sensor module for volcanic hazard monitoring - First long-term experiment and performance assessment

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    A seafloor multi-sensor module with real-time data transmission, named CUMAS (Cabled Underwater Module for Acquisition of Seismological data), has been deployed in January 2008 in the Gulf of Pozzuoli, in the Campi Flegrei caldera (southern Italy), which is one of the most active volcanic areas in the world. The sensors installed in CUMAS were selected to monitor a set of signals related to the local seismicity as well as the ground uplift and subsidence of the seafloor that are related to the bradyseismic phenomenon. In particular, together with a broad-band three-component seismometer and a low-frequency hydrophone, a seafloor water-pressure sensor is used to assess the feasibility of measurements of the slow vertical movement of the seafloor (bradyseism). Further sensors are acquired by two embedded Linux computers, namely tilt and heading sensors for the measure of the actual module orientation on the seafloor, and status sensors that monitor the state of health of the vessel (e.g., internal temperature, power absorption, water intrusion). The underwater acquisition systems are linked to a support infrastructure, a floating buoy (elastic beacon), through an electro-mechanical cable with an Ethernet line. The buoy provides the needed power supply thanks to batteries charged by solar panels and a wind- generator. A Wi-Fi antenna on the buoy is used to transmit the seafloor data from the sea surface to the land acquisition centre in the city of Naples. A meteorological station is also mounted on the buoy, to allow the correlation of the air and seafloor data. CUMAS, although based on commercial sensors, relies on an original system for the centralized management of a wide set of geophysical and physical oceanographic sensors, that handles the continuous data acquisition and real-time data transmission. After the installation in the Gulf of Pozzuoli at about 100 m w.d., and after a test period, CUMAS uninterruptedly operated from May 2008 to June 2009, thus providing continuous geophysical data to the Monitoring Center of the Campi Flegrei volcanic areas, managed by the Istituto Nazionale di Geofisica e Vulcanologia. The long-term operational performance of CUMAS is presented here, together with the first results from the analysis of the geophysical long time-series acquired. Examples of the acquired signals, especially geophysical data, will be presented to point out the high quality in term of signal-to-noise ratio. In particular, earthquake recordings obtained from the hydrophone resulted of comparable quality to the seismic data acquired on land by the permanent network, thus demonstrating the suitability of hydrophones to monitor the seismic activity of the caldera
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