Early prenatal diagnosis of congenital hypophosphatasia: Case report

Congenital hypophosphatasia is an autosomal recessive disorder, which usually has a fatal outcome during the neonatal period. This report presents the prenatal diagnosis of hypophosphatasia at 16 weeks of gestation. The characteristic ultrasonic findings in this abnormality demonstrate the superiority of ultrasound as compared with radiography.     

Systemic accident risk assessment in air traffic by Monte Carlo simulation

A systemic accident model considers accidents as emergent phenomena from variability and interactions in a complex system. Air traffic risk assessments have predominantly been done by sequential and epidemiological accident models. In this paper we demonstrate that Monte Carlo simulation of safety relevant air traffic scenarios is a viable approach for systemic accident assessment. The Monte Carlo simulations are based on dynamic multi-agent models, which represent the distributed and dynamic interactions of various human operators and technical systems in a safety relevant scenario. The approach is illustrated for a particular runway incursion scenario, which addresses an aircraft taxiing towards the crossing of an active runway while its crew has inappropriate situation awareness. An assessment of the risk of a collision between the aircraft taxiing with an aircraft taking-off is presented, which is based on dedicated Monte Carlo simulations in combination with a validation approach of the simulation results. The assessment particularly focuses on the effectiveness of a runway incursion alert system that warns an air traffic controller, in reducing the safety risk for good and reduced visibility conditions.     

Performance of an in situ passive sampling system for metals in stormwater

A passive sampler has been developed and is demonstrated in situ for urban runoff. The passive sampler is compared to conventional composite (time-dependent and flow-weighted) bottle sampling during and between storm events. The sampling was carried out at established stormwater stations; before and after a stormwater detention pond. In situ deployment of the passive sampler provides the metal concentrations, corresponding to the electrochemically available fraction of total metal, for time-dependent samples collected in parallel. The sampler provides improved accuracy compared to bottle sampling because contamination during sample transport and handling is minimised. Laboratory handling is reduced by direct analysis of the accumulated metals on the receiving membrane by laser ablation inductively coupled plasma mass spectrometry. Passive sampling also solves the problem of metal speciation change during transport to the laboratory, which is a potential problem for bottle samples. The low cost and convenience of the passive sampler and subsequent analysis should allow significantly more extensive spatial and temporal monitoring of metals in the aquatic environment than has previously been possible.     

Developing a framework for safety validation of multi-stakeholder changes in air transport operations

The high volume of air traffic over Europe is expected to double within the next 15 years. This requires changes in the airspace structure and in the organisation of air transport operations that involve multiple stakeholders. Changes, by regulation, require a sufficient safety validation, in order to show that the changed situation is safe and will remain safe during an applicable period. Many methods and techniques exist that can be used to support such safety validation process. However, for air transport operations, the stakeholders involved are numerous and diverse, and there are no guidelines on how to address their roles, responsibilities and goals during development and validation.This paper develops a safety validation framework that emphasises the active roles and collaboration of multiple stakeholders during the development phases of air transport operations. The framework is developed in three steps: First, established validation views from literature are identified and analysed to reveal open issues when it comes to their use for multi-stakeholder changes in air transport operations. Next, validation views emerging beyond the established ones are identified, and evaluated on whether they address the open issues. Finally, the strong points of established and emerging views are combined into a novel framework.     

Social regulation of egg-laying by queenless honeybee workers (Apis mellifera L.)

Summary If a honeybee (Apis mellifera L.) colony loses its queen and remains queenless, a small percentage of the workers will develop into egg-layers and subsequently will produce males. The process of differentiation into laying and non-laying workers is accompanied by a great deal of aggression within the colony. In this study, I tried to establish the relationship between the potential to become egg-layers and behavioural differences at the individual level. To eight observation hives, I introduced 200 individually marked workers of similar age and observed their behavioural differentiation during a queenless period. Shortly after the first egg-laying worker appeared, the marked workers were dissected in order to determine their level of ovarian activation. The future laying-workers seemed to be slightly more involved in the rearing of new queens than other workers. As reported by other authors, aggression was mostly directed towards workers with activated ovaries. Only a very small number of aggressive workers were aggressive; on an average, slightly fewer of these marked workers had activated ovaries. Aggression resulted in physical damage in only a small number of cases. The possible disadvantage of aggression for the bees under attack is discussed, as well as the possible benefit for the aggressors. Evidence is presented that the most detrimental effect of aggression for bees under attack is the fact that they lose considerable quantities of food through trophallaxis to other workers. Workers with activated ovaries withdrew inside empty cells significantly more often than other workers, possibly to avoid attacks. Aggressive workers were (almost) never seen to receive food from the bees they attacked. It is suggested that by preventing other workers from becoming egg-layers, aggressors increase their own chances of future reproduction.