The Murchison Widefield Array is a Square Kilometre Array Precursor. The telescope is located at the Murchison Radio–astronomy Observatory in Western Australia. The MWA consists of 4 096 dipoles arranged into 128 dual polarisation aperture arrays forming a connected element interferometer that cross-correlates signals from all 256 inputs. A hybrid approach to the correlation task is employed, with some processing stages being performed by bespoke hardware, based on Field Programmable Gate Arrays, and others by Graphics Processing Units housed in general purpose rack mounted servers. The correlation capability required is approximately 8 tera floating point operations per second. The MWA has commenced operations and the correlator is generating 8.3 TB day−1 of correlation products, that are subsequently transferred 700 km from the MRO to Perth (WA) in real-time for storage and offline processing. In this paper, we outline the correlator design, signal path, and processing elements and present the data format for the internal and external interfaces.

The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80–300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3-km diameter area. Novel hybrid hardware/software correlation and a real-time imaging and calibration systems comprise the MWA signal processing backend. In this paper, the as-built MWA is described both at a system and sub-system level, the expected performance of the array is presented, and the science goals of the instrument are summarised.

Functional laryngeal dyskinesia is a disorder that presents with stridor. Failure to recognize its features can result in inappropriate investigation and treatment for a condition that has a psychogenic origin. The key feature in diagnosis is paradoxical vocal fold adduction on inspiration, as seen on fibre-optic nasendoscopy. This phenomenon together with the associated stridor may disappear after distraction techniques or when the patient is asleep. We present five such cases which presented to hospitals in south west London over a 12 month period.

Mycotic aneurysms of the extracranial carotid arteries are extremely rare. A case is reported of a false aneurysm of the left external carotid artery. This developed secondary to cervical lymphadenitis which did not settle with high dose antibiotic therapy. The diagnosis was made on investigation with carotid doppler ultrasound and confirmed with computerized tomography. Digital subtraction angiography was performed to highlight the vascular anatomy. In addition percutaneous balloon catheter control of blood flow in the external carotid artery was used as an adjunct to surgical management.

Laryngeal chondroradionecrosis is an unusual condition which may present many years after the initial radiotherapy. We present a case of late onset chondroradionecrosis which was complicated by invasive candidiasis of the arytenoid cartilages which had themselves been extruded through the laryngeal mucosa.

Flexible nasendoscopy is now an integral part of the diagnostic process in Otorhinolaryngology. Topical local anaesthesia is generally recommended and cocaine is usually the drug of choice in view of its concurrent vasoconstrictor action. However, it is expensive, a controlled drug and serious side effects have been reported. Co-phenylcaine forte is a new preparation which also has both local anaesthetic and vasoconstrictor properties. This study compares the efficacy of cocaine and Co-phenylcaine in flexible nasendoscopy and concludes that they provide similar local anaesthesia and vasoconstriction of the nasal mucosa. Co-phenylcaine forte can therefore be used as an alternative to cocaine in flexible nasendoscopy.

Wegener's granulomatosis is a multi-system disease characterized by granuloma formation and a necrotizing vasculitis. It classically presents with involvement of the upper and lower respiratory and renal systems. However locoregional disease is common and may include otological manifestations. Facial nerve palsy has been reported during the course of the disease process but it is extremely rare for it to be the presenting feature. Previously reported cases have involved a protracted diagnostic process including exploratory tympanotomy, mastoidectomy and facial nerve decompression. We report a case of Wegener's granulomatosis which presented with a facial nerve palsy. An early diagnosis was achieved by measurement of the erythrocyte sedimentation rate (ESR), followed by serological assay of cytoplasmic anti-neutrophil cytoplasmic antibody (cANCA). Histological examination of nasal mucosal biopsies confirmed granuloma formation consistent with a diagnosis of Wegener's granulomatosis. This allowed early treatment with immunosuppressive therapy and avoided unnecessary and potentially hazardous middle ear surgery.