The use of Bayesian Belief Networks (BBNs) to probe deeper into railway safety management systems - Two studies from Great Britain and Italy.

The importance of Safety Management Systems (SMS) to the railway industry is underlined by the fact that all organisations operating on UK railways are required by law to have one. Analysing SMSs can provide a reliable systemic tool to identify hazards and weaknesses within complex systems like the railway, making it possible to significantly increase safety, reducing the odds of near misses and accidents. However, there is little empirical research evidence to determine the impact on safety of a structured SMS. The current paper describes two studies which use Bayesian Belief Networks (BBN) to conceptualise SMSs and their impact on front-line performance. The paper presents the usefulness of BBNs to compare complex systems and reconcile cultural differences within the railway industry, identifying factors that are deemed vital within Italy and Britain. The two studies allowed us to identify the most influential factors within a SMS and how they interact with each other, as well as the strength of the identified relationships. A BBN is particularly useful in estimating how changing some of the node states (e.g., by making safety leadership present) affected the other factors. The current study showed that safety leadership has an impact on the SMSs of the British and Italian railway industries.

A new device (FAQ.FIX®) for orthodontic bracket placement in straight wire technique.

BACKGROUND: In straight wire preadjusted appliances, all the information required to position the teeth in three planes is included in the brackets placed at the midpoint of the facial axis of the clinical crown, defined by facial axis point (FA). Central to this technique is the bracket placement.Preadjusted orthodontic appliances cannot get the right tooth position with a straight wire because of the inaccuracy of bracket placement. Horizontal, axis, vertical, and base are the most common bracket placement errors.The aim of this paper was to describe a bracket positioner to fix the brackets accurately (Q) on FA point (FAQ.FIX®) in direct or indirect bonding. METHODS: After the development of a prototype, a FAQ.FIX® along with a Bracket Placement Clinical Chart was developed and thus described. RESULTS: FAQ.FIX® along with the Bracket Placement Clinical Chart may facilitate the accuracy in bracket placement on FA point avoiding the most common bracket placement errors regardless the operator skill, even in particular or difficult case. CONCLUSIONS: FAQ.FIX®may represent a significant improvement in the bracket placement compared to the bracket eye and the traditional gauges positioning. Further studies will be needed to verify the clinical efficacy.

Giant cell arteritis: the importance of immediate and appropriate diagnosis and treatment for better prognosis.

This article describes the case of a 68-year-old patient suffering from giant cell arteritis (also known as Horton's arteritis or temporal arteritis). The patient came to our attention due to a large and sudden visual loss caused by the occlusion of major retinal arteries. The patient had neuralgic pain in the face. The next day, for a thorough examination, the patient went to the day hospital with a further worsening of the visual loss which required immediate admission to the ophthalmological ward for hospitalization lasting 10 days. During the observation period it was difficult to make an instant diagnosis due to the absence of clinical signs or diagnostic tests for Horton's arteritis. Only after the third day of hospitalization, when corticosteroid therapy was undertaken following the appearance of significant systemic symptoms, did the patient begin to show a gradual improvement in overall clinical status. The case highlights the difficulty in making a rapid diagnosis of giant cell arteritis and the efficacy of early steroid therapy in this vascular autoimmune disease that otherwise may result in irreversible functional and debilitating systemic damage.

Photorefractive keratectomy in the management of refractive accommodative esotropia in young adult patients.

PURPOSE: To evaluate the visual, motor, and sensory outcomes of photorefractive keratectomy (PRK) in the treatment of purely refractive accommodative esotropia in young adult patients. SETTING: Policlinico Umberto I, Department of Ophthalmology, Rome, Italy. METHODS: This prospective study comprised patients with hyperopia and purely accommodative hyperopic esotropia. A complete ophthalmologic examination was performed preoperatively and 1, 3, and 12 months postoperatively. The examination included uncorrected (UDVA) and corrected (CDVA) distance visual acuities and orthoptic and sensory tests. All patients also had keratometry, pachymetry, and corneal topography assessment before and after treatment. Treatment was performed using a Technolas 217 excimer laser. RESULTS: Thirty eyes of 15 patients (mean age 30.8 years) were treated. Preoperatively, the CDVA was 20/30 or better in all eyes and the mean cycloplegic spherical equivalent (SE) was +3.50 diopters (D). One year postoperatively, the UDVA was 20/30 or better in all eyes and the mean SE was -0.01 D. The mean esotropic deviation for distance vision without correction preoperatively was 8.7 prism diopters. At 1 year of follow-up, 12 patients achieved orthophoria and 3 patients had a reduction in the angle of deviation. There were no intraoperative or postoperative complications. Stereopsis was unaffected by treatment in all patients. CONCLUSIONS: Photorefractive keratectomy was effective in the treatment of purely accommodative esotropia in young adult patients at a follow-up of 1 year. There were no cases of visual acuity loss or complications from the laser treatment.