Accepting splicing systems with permitting and forbidding words

Abstract: In this paper we propose a generalization of the accepting splicingsystems introduced in Mitrana et al. (Theor Comput Sci 411:2414?2422,2010). More precisely, the input word is accepted as soon as a permittingword is obtained provided that no forbidding word has been obtained sofar, otherwise it is rejected. Note that in the new variant of acceptingsplicing system the input word is rejected if either no permitting word isever generated (like in Mitrana et al. in Theor Comput Sci 411:2414?2422,2010) or a forbidding word has been generated and no permitting wordhad been generated before. We investigate the computational power ofthe new variants of accepting splicing systems and the interrelationshipsamong them. We show that the new condition strictly increases thecomputational power of accepting splicing systems. Although there areregular languages that cannot be accepted by any of the splicing systemsconsidered here, the new variants can accept non-regular and even non-context-free languages, a situation that is not very common in the case of(extended) finite splicing systems without additional restrictions. We alsoshow that the smallest class of languages out of the four classes definedby accepting splicing systems is strictly included in the class of context-free languages. Solutions to a few decidability problems are immediatelyderived from the proof of this result

in: Damage Control Resuscitation

Airway care of the patient with life threatening haemorrhage presents many challenges during damage control resuscitation. The essential requirements are to maintain oxygenation at all stages of care and when necessary deliver general anaesthesia to facilitate invasive haemorrhage control procedures. In the remote, pre-hospital setting, providers must be able to assess the airway and intervene with a range of strategies to prevent hypoxaemia. These interventions may vary from basic airway opening manoeuvres to advanced techniques such as drug-assisted rapid sequence intubation. The initial delivery of these skills in remote settings will be the responsibility of whichever medical provider is present, and so their training, equipment and decision-making skills must reflect the challenges they will face. Rapid sequence intubation skills may not be widely available in remote environments and so providers must be equipped with alternative airway management strategies including cricothyrotomy and use of extraglottic airway devices. When invasive haemorrhage control procedures are required for patients with life threatening haemorrhage, rapid sequence intubation will need to be performed. This procedure carries significant risk in the presence of haemorrhagic shock. Providers must be aware of the hypotensive effects of induction agents and the adverse impact of positive pressure ventilation upon cardiac output in the presence of life threatening haemorrhage. The risks of intubation should be minimised with appropriate blood production administration and ventilation techniques as part of a coordinated damage control resuscitation strategy