33 research outputs found
The effects of a modest dose of alcohol on executive functioning and prospective memory
Rationale
Acute alcohol intoxication selectively impairs executive functioning and prospective memory (PM). Much previous researches in this area have used laboratory-based tasks that may not mimic functions that individuals with dysexecutive syndrome have problems with in their everyday life. The present study aimed to assess the effects of a modest dose of alcohol on executive functioning and PM using a virtual reality task and investigate the role of executive planning in PM performance.
Methods
Forty healthy participants were administered 0.4âg/kg alcohol or matched placebo in a double-blind design. Executive function and PM were assessed using the JansariâAgnewâAkessonâMurphy (JAAM) task, requiring participants to play the role of an office worker.
Results
Alcohol intoxication selectively impaired executive function and PM. The participants in the alcohol condition performed worse on the planning, prioritisation, creativity and adaptability executive subscales and also on the time-based and event-based PM tasks. However, alcohol did not impair the selection executive function task or the action-based PM task.
Conclusions
The results provide further support for the effects of alcohol on executive functioning and PM. In addition, the results suggest that such deficits may be present at relatively modest doses of alcohol and in the absence of a subjective feeling of intoxication
Comparando os mĂ©todos paramĂ©trico e nĂŁo-paramĂ©trico na determinação do valor crĂtico do teste estatĂstico de mĂ©dias proposto por Hayter e Tsui
Upperâtropospheric inflow layers in tropical cyclones
Three-dimensional numerical simulations of tropical cyclone intensification with sufficient vertical resolution have shown the development of a layer of strong inflow just beneath the upper-tropospheric outflow layer as well as, in some cases, a shallower layer of weaker inflow above the outflow layer. Here we provide an explanation for these inflow layers in the context of the prototype problem for tropical cyclone intensification, which considers the evolution of a vortex on anf-plane in a quiescent environment, starting from an initially symmetric, moist, cloud-free vortex over a warm ocean. We attribute the inflow layers to a subgradient radial force that exists through much of the upper troposphere beyond a certain radius. An alternative explanation that invokes classical axisymmetric balance theory is found to be problematic. We review evidence for the existence of such inflow layers in recent observations. Some effects of the inflow layers on the storm structure are discussed
On event based state estimation
To reduce the amount of data transfer in networked control systems and wireless sensor networks, measurements are usually taken only when an event occurs, rather than at each synchronous sampling instant. However, this complicates estimation and control problems considerably. The goal of this paper is to develop a state estimation algorithm that can successfully cope with event based measurements. Firstly, we propose a general methodology for defining event based sampling. Secondly, we develop a state estimator with a hybrid update, i.e. when an event occurs the estimated state is updated using measurements; otherwise the update makes use of the knowledge that the monitored variable is within a bounded set that defines the event. A sum of Gaussians approach is employed to obtain a computationally tractable algorithm
Mechanical drilling processes for titanium alloys: a literature review
Titanium and its alloys (Ti) are attractive for many applications due to their superior properties. However, they are regarded as hard-to-machine materials. Drilling is an important machining process since it is involved in nearly all Ti applications. It is desirable to develop cost-effective drilling processes for Ti and/or improve the cost-effectiveness of currently-available processes. Such development and improvement will be benefited by a comprehensive literature review of drilling processes for Ti. This paper presents a literature review on mechanical drilling processes for Ti, namely, twist drilling, vibration assisted twist drilling, ultrasonic machining, and rotary ultrasonic machining. It discusses cutting force, cutting temperature, tool wear and tool life, hole quality (diameter and cylindricity, surface roughness, and burr), and chip type when drilling of Ti using these processes