The influence of previous experiences on participant performance during maritime simulation testing

Motion simulation platforms are often used to study the effects of moving environments on the postural stability of maritime workers. During motion simulation studies, the effects of previous experience are not often considered when recruiting control participants. Previous experience in motion simulation studies may violate assumptions of novice participants, and previous experiences in activities that regularly challenge balance may also influence performance. Thus, the purpose of this study was to investigate the effects of previous participation in motion simulation studies or previous skill training (specifically dance) on postural stability and lower limb neuromuscular activity in a simulated ocean environment. Thirty-seven participants were recruited; 12 participants with previous motion bed experience, 13 dancers, and 12 control participants. Results indicated that both motion bed experience and dance training had significantly better postural stability performance and decreased lower limb muscle activity compared to truly inexperienced control subjects during motion simulation testing.     

A killer adversary for quicksort

Quicksort can be made to go quadratic by constructing input on‐the‐fly in response to the sequence of items compared. The technique is illustrated by a specific adversary for the standard C qsort function. The general method works against any implementation of quicksort – even a randomizing one – that satisfies certain very mild and realistic assumptions. Copyright © 1999 John Wiley & Sons, Ltd.     

Synthesis of graphene paper from pyrolyzed asphalt

A new technique for the synthesis of large sheets (>10 cm²) of multi-layered graphene is presented. The condensation onto a heated surface (≈650 °C) of fumes from the thermal decomposition of asphalt in a ceramic crucible produces carbon films with a metallic sheen. Heating was done by a Fisher burner (natural gas/air) flame and the crucible was covered but exposed to laboratory atmosphere. These films were determined to be multi-layered graphene by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), Raman and infrared spectroscopy and X-ray diffraction. XPS indicates that the films are primarily sp² hybridized carbon with small amounts of sp³ C–H and C–O or C–N functionalities. Based on the D band shift (1593 cm⁻¹) and the ratio of D band to G band (1354 cm⁻¹) of 0.93, the Raman spectrum also indicates that the material is sp² C with some nanocrystalline features. The infrared spectrum exhibits A_1U (868 cm⁻¹) and E_1U (1599 cm⁻¹) stretching of the intralayer bonds of graphene. This form of chemical vapor deposition may be a scalable to give much larger surface areas. Furthermore, the process does not require metal substrates. Deposition onto silica nanosprings and diatomites is demonstrated.     

In situ profiling of microbial communities in full-scale aerobic sequencing batch reactors treating winery waste in australia

On-site aerobic sequencing batch reactor (SBR) treatment plants are implemented in many Australian wineries to treat the large volumes of associated wastewater they generate. Yet very little is known about their microbiology. This paper represents the first attempt to analyze the communities of three such systems sampled during both vintage and nonvintage operational periods using molecular methods. Alphaproteobacterial tetrad forming organisms (TFO) related to members of the genus Defluviicoccus and Amaricoccus dominated all three systems in both operational periods. Candidatus 'Alysiosphaera europaea' and Zoogloea were codominant in two communities. Production of high levels of exocellular capsular material by Zoogloea and Amaricoccus is thought to explain the poor settleability of solids in one of these plants. The dominance of these organisms is thought to result from the high COD to N/P ratios that characterize winery wastes, and it is suggested that manipulating this ratio with nutrient dosing may help control the problems they cause.     

Spectral index method for polarized modes in semiconductor ribwaveguides

A fast way of modeling polarized modes in semiconductor rib waveguides is presented and shown to be in excellent agreement with a semivectorial finite-difference computer program. The method uses little storage and has been implemented on a personal computer     

Generalisability of sensory gating during passive movement of the legs

Movement-related gating of somatosensory evoked potentials in the upper limb is restricted mainly to nerve stimulation supplying the moved limb segment. In the lower limb, this principle may not be followed. Tibial nerve (stimulation at the knee) somatosensory evoked potentials (SEPs) and soleus H reflexes exhibit quite similar patterns of modulation during movement. We hypothesised that movement-related gating of initial SEPs in the leg would be generalised from ipsilateral to contralateral leg movement and that such sensory gating would not be generalised to modalities with no functional relevance to the movement. Somatosensory, visual, and auditory evoked potentials (SEPs, VEPs, and AEPs) were recorded from scalp electrodes during unilateral passive movement. Short-latency tibial nerve SEPs, representing the first cortical components, and soleus H reflexes in both the moved leg and the stationary leg were attenuated compared to non-movement controls (p<0.05). Neither VEPs nor middle latency AEPs were modulated (p>0.05). We conclude that sensory gating occurs during contralateral movement. This gating is absent in other sensory modalities with no apparent functional relationship to the imposed movement.     

Bedside safety rails: assessment of strength requirements and the appropriateness of current designs

Bedside safety rails are used extensively throughout hospitals and residential care environments as a safety device to protect people against the risk of falling out of bed. However, several adverse incidents involving body entrapment have been linked to their use, which have resulted in serious injury to the bed occupants and, in more extreme cases, fatalities. Internationally agreed standards (i.e. European Committee for Standardisation (CEN) standards) for the design and testing of bed rails have recently been developed and are targeted at improved safety requirements (European Committee for Standardisation 19972000). The purpose of the present study was to: 1) determine whether the CEN test procedure for assessing bed rail strength and rigidity requirements is consistent with human force exertions to which bed rails may be exposed; 2) carry out loading tests on bed rails currently in use throughout the UK to determine whether they comply with the current safety recommendations proposed by the CEN standards.A laboratory study was conducted to determine the force exertions of 20 participants performing seven tasks (including activities of both bed occupants and care providers), which were considered representative of the forces to which bed rails could be exposed during normal use. Forces exerted by participants were measured using a force platform and distortions of the bed rails leading to potential entrapment zones were measured using linear displacement transducers. Static load tests were then conducted, in which incremental point loading was applied at the most adverse points on each of nine different bed rails (commonly used in UK nursing and residential care homes) in accordance with the test procedure detailed in the current CEN standards.Maximum static forces exerted by participants were found to range between 250 N and 350 N, which were within the 500 N force tolerance requirements set by the standards. Dynamic tasks involving 'rolling aggressively' against the bed rail produced the highest peak force of 722 N. None of the bed rails included in this study met the requirements of the CEN test procedures, principally due to horizontal lateral displacements being in excess of 50 mm for a 500 N applied force and/or the bed rails' inability to withstand inward horizontal forces of 500 N. Bed rails used with divan beds were often unable to withstand forces greater than 300 N due to turning moments exceeding the bed rail's restraining mechanism.Current CEN standards for assessing the strength and rigidity of bedside safety rails appear to be consistent with the human forces that might arise as a consequence of the normal movement and activities of a bed occupant or care provider. Although compliance with existing standards is not compulsory, findings from the tests carried out on the selection of bed rails in current use throughout the UK highlight the need for improvements in the design and manufacture of bed rails.     

Following the cognitive work analysis train of thought: exploring the constraints of modal shift to rail transport

Environmental concerns show that transport is responsible for almost a quarter of all greenhouse gas emissions, and it is also the fastest growing sector. Modal shift towards public transport could help slow down, or even reverse, this trend. There appear to be a number of constraints that are preventing this from happening. This paper explores the constraints to modal shift to rail transport from the perspective of cognitive work analysis, specifically the abstraction hierarchy, the contextual activity template and social organisational and cooperation analyses. Whilst these analyses may not present any new barriers, they do show how the constraints are interlinked in an explicit manner. These interrelations are important for two reasons. First, in consideration of constraint removal, one must anticipate the likely effects on the remainder of the system. Second, by linking functions and situations, new concepts of travel may be identified and explored.

Practitioner Summary: The purpose of this study was to use a semi-structured approach to identifying constraints to modal shift from a variety of perspectives. It is argued that cognitive work analysis offers a new way of thinking about the modal shift problem and helps to generate new insights into potential solutions.