Fatigue as a key human factor in complex sociotechnical systems: Vessel Traffic Services.

Background: Vessel Traffic Services (VTS) are considered a subsystem of people, whose mission is to improve the effectiveness and efficiency of maritime transport within the maritime system. VTS operate as a control system where Vessel Traffic Services Operators (VTSOs) must cope with a complex environment to make up for safe and efficient maritime transport, so it is essential to understand how these operators maintain control through adapting to the uncertain and dynamic environment of maritime traffic. This multidisciplinary study explores how human factors within this complex sociotechnical system, means VTS, play a role in maritime safety, specifically focusing on fatigue, which is considered a key variable for VTSOs' performance. In this context, the research has focused on the assessment of fatigue with psychological and operational instruments to highlight the importance of the human element in CSSs. Objective: To study the intra and inter-individual differences in fatigue ratings and their relationships with other personal and environmental variables: mental workload, work shifts, reaction time, and hours of usual sleep. Methods: The study was conducted in two of the 19 Spanish Maritime Rescue Coordination Centers (MRCCs) with a sample of 23 active VTSOs (82.14% of the staff). Both objective and standardized subjective measures were used to assess fatigue and associated sleepiness (Borg RPE, Nasa-TLX, Stanford Sleepiness Scale, and Self-Assessment Manikin Scale). Results: A significant positive correlation between fatigue and mental workload was found, being more prevalent in the night shift, which shows a bigger variation in these variables. A significant difference was found in the increase in fatigue experienced throughout the shift depending on the hours of usual sleep, being smaller in the group of subjects reporting to sleep more. Conclusion: The human element is key to maritime safety related to Vessel Traffic Services, so it is of paramount importance to consider certain measures to counteract the negative effects of fatigue. A proper organization of duties on/off periods, assessment of work and rest schedules, and the implementation of fatigue management programs based on sleep education are recommended.

Device-associated infection rates in Adult Intensive Care Units in Catalonia: VINCat Program findings.

Hospital-acquired infections are a leading cause of morbidity and mortality, especially in the intensive care unit (ICU). Surveillance of device-associated infections plays a major role in infection control programs. In 2006, the Surveillance Program of Nosocomial Infections in Catalonia (VINCat Program) was started, with the major aim of reducing infection rates through a process of active monitoring. The study period comprised calendar years 2008 (with 21 ICUs participating), 2009 (with 21 ICUs participating), and 2010 (with 28 ICUs participating). Each participating hospital was required to have an infection control team made up of at least one physician, an infection surveillance nurse, and a microbiology laboratory. Hospitals were classified into three groups according to their size. Central venous catheter-associated bloodstream infection (CVC-BSI) and ventilator-associated pneumonia (VAP) were chosen as the device-associated infections to analyze. Incidence rates of device-associated infections were calculated by dividing the total number of device-associated infection (VAP or CVC-BSI) days by the total number of days use for the relevant device. Mechanical ventilation use ranged from 0.10 to 0.85 days (overall, 0.35), and central venous catheter use ranged from 0.18 to 0.98 days (overall, 0.65). Incidence rates of VAP ranged from 7.2 ± 3.7 to 10.7 ± 9.6 episodes of VAP/1000 ventilator days. Incidence rates of CVC-BSl ranged from 1.9 ± 1.6 to 2.7 ± 2.0 episodes of CVC-associated bloodstream infection/1000 central venous catheter days. The implementation of the VINCat Program allowed monitoring of nosocomial device-associated infections in ICUs in Catalonia and enabled corrective measures in ICUs with increased incidences of device-associated infections.

Mechanism of caveolin filament assembly.

Caveolin-1 was the first protein identified that colocalizes with the approximately 10-nm filaments found on the inside surface of caveolae membranes. We have used a combination of electron microscopy (EM), circular dichroism, and analytical ultracentrifugation to determine the structure of the oligomers that form when the first 101 aa of caveolin-1 (Cav(1-101)) are allowed to associate. We determined that amino acids 79-96 in this caveolin-1 fragment are arranged in an alpha-helix. Cav(1-101) oligomers are approximately 11 nm in diameter and contain seven molecules of Cav(1-101). These subunits, in turn, are able to assemble into 50 nm long x 11 nm diameter filaments that closely match the morphology of the filaments in the caveolae filamentous coat. We propose that the heptameric subunit forms in part through lateral interactions between the alpha-helices of the seven Cav(1-101) units. Caveolin-1, therefore, appears to be the structural molecule of the caveolae filamentous coat.