3,816 research outputs found

    AIRNET: A real-time comunications network for aircraft

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    A real-time local area network was developed for use on aircraft and space vehicles. It uses token ring technology to provide high throughput, low latency, and high reliability. The system was implemented on PCs and PC/ATs operating on PCbus, and on Intel 8086/186/286/386s operating on Multibus. A standard IEEE 802.2 logical link control interface was provided to (optional) upper layer software; this permits the controls designer to utilize standard communications protocols (e.g., ISO, TCP/IP) if time permits, or to utilize a very fast link level protocol directly if speed is critical. Both unacknowledged datagram and reliable virtual circuit services are supported. A station operating an 8 MHz Intel 286 as a host can generate a sustained load of 1.8 megabits per second per station, and a 100-byte message can be delivered from the transmitter's user memory to the receiver's user memory, including all operating system and network overhead, in under 4 milliseconds

    Bounded decision-making, teachers’ reflection, and organisational learning: how research can inform teachers and teaching

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    Despite numerous efforts to align educational practice more closely with findings from educational research, there is little clarity about how educational practitioners can, in principle, use research. We propose a conceptualisation based on how research can contribute to practitioners’ thinking: specifically, our framework proposes that research can inform bounded decision‐making, teachers’ reflection and organisational learning. Practitioners can also use research without being aware that they are doing so. We argue that this conceptualisation of research use has potential to inform researchers and practitioner

    Modifications to Chevron N-Layer Computer Program

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    This report documents changes made to the Chevron N-layer computer program to: Include superposition principles. Calculate strain energy density (or work) at specified locations within the pavement structure. Analyze pavement response at specified radii from one circularly loaded area to permit comparison of analyses by the program as originally written with results incorporating superposition principles. Evaluate pavement response to any combination of loads on circular areas defined by XY coordinates on the surface. Loads and contact pressures are permitted to be different from one loaded area to another, but must be constant for any one loaded area. Simulate dynamic loads as the difference between the root mean squares of the maximum and minimum dynamic loads. This analysis is appropriate for constant vibratory testers such as Road Raters and Dynaflects. Moduli of asphaltic concrete must be adjusted for frequency effects

    On the informational content of wage offers

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    This article investigates signaling and screening roles of wage offers in a single-play matching model with two-sided unobservable characteristics. It generates the following predictions as matching equilibrium outcomes: (i) “good” jobs offer premia if “high-quality” worker population is large; (ii) “bad” jobs pay compensating differentials if the proportion of “good” jobs to “low-quality” workers is large; (iii) all firms may offer a pooling wage in markets dominated by “high-quality” workers and firms; or (iv) Gresham’s Law prevails: “good” types withdraw if “bad” types dominate the population. The screening/signaling motive thus has the potential of explaining a variety of wage patterns

    Rate-dependent propagation of cardiac action potentials in a one-dimensional fiber

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    Action potential duration (APD) restitution, which relates APD to the preceding diastolic interval (DI), is a useful tool for predicting the onset of abnormal cardiac rhythms. However, it is known that different pacing protocols lead to different APD restitution curves (RCs). This phenomenon, known as APD rate-dependence, is a consequence of memory in the tissue. In addition to APD restitution, conduction velocity restitution also plays an important role in the spatiotemporal dynamics of cardiac tissue. We present new results concerning rate-dependent restitution in the velocity of propagating action potentials in a one-dimensional fiber. Our numerical simulations show that, independent of the amount of memory in the tissue, waveback velocity exhibits pronounced rate-dependence and the wavefront velocity does not. Moreover, the discrepancy between waveback velocity RCs is most significant for small DI. We provide an analytical explanation of these results, using a system of coupled maps to relate the wavefront and waveback velocities. Our calculations show that waveback velocity rate-dependence is due to APD restitution, not memory.Comment: 17 pages, 7 figure

    In the Interests of clients or commerce? Legal aid, supply, demand, and 'ethical indeterminacy' in criminal defence work

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    As a professional, a lawyer's first duty is to serve the client's best interests, before simple monetary gain. In criminal defence work, this duty has been questioned in the debate about the causes of growth in legal aid spending: is it driven by lawyers (suppliers) inducing unnecessary demand for their services or are they merely responding to increased demand? Research reported here found clear evidence of a change in the handling of cases in response to new payment structures, though in ways unexpected by the policy's proponents. The paper develops the concept of 'ethical indeterminacy' as a way of understanding how defence lawyers seek to reconcile the interests of commerce and clients. Ethical indeterminacy suggests that where different courses of action could each be said to benefit the client, the lawyer will tend to advise the client to decide in the lawyer's own interests. Ethical indeterminacy is mediated by a range of competing conceptions of 'quality' and 'need'. The paper goes on to question the very distinction between 'supply' and 'demand' in the provision of legal services

    Simultaneous dynamic electrical and structural measurements of functional materials

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    A new materials characterization system developed at the XMaS beamline, located at the European Synchrotron Radiation Facility in France, is presented. We show that this new capability allows to measure the atomic structural evolution (crystallography) of piezoelectric materials whilst simultaneously measuring the overall strain characteristics and electrical response to dynamically (ac) applied external stimuli

    The acute effects of continuous and intermittent cycling on executive function in children

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    This study assessed the effect of acute continuous and intermittent physical activity (PA) on children's executive function (EF). Twenty-four participants (14 boys M = 10.32 ± 0.48 years), using a within-subjects design, performed a continuous (70% HRmax) and an intermittent (≄85%HRmax; 12 bouts: 30 s work, 45 s rest) PA bout of cycling, both lasting 15 min. Executive function was assessed using the Stroop task, Digit Span and Corsi Blocks tests and these were administered before and 1 min and 30 min post PA. Comparing both conditions, performance at the Stroop task (i.e., reaction time) improved in the continuous condition after 1 min and after 30 min (congruent stimuli) (mean diff = 126 ms ± 59; p = 0.047 and mean diff = 89 ms ± 38; p = 0.031, respectively). The intermittent condition improved at 30 min post (congruent and incongruent) (mean diff = 116 ms ± 46; p = 0.021 and mean diff = 111 ms ± 49; p = 0.039, respectively) showing a delayed benefit from the PA bout and greater improvements compared to the continuous condition. Verbal memory was improved for the continuous condition 1 min post only and no effects on visual memory were observed for both experimental conditions. The results demonstrated that both acute PA bouts might be a time-efficient approach for enhancing EF, with intermittent PA having a delayed and greater benefit

    The Acute Effects of Cognitively Demanding Physical Activity on Inhibitory and Affective Responses in Children:An Online-Based Mixed Methods Approach

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    This online study investigated the acute effects of a cognitively demanding physical activity (CDPA) vs a simple physical activity (SPA) bout on children’s inhibitory and affective responses. Using a counterbalanced within-subjects’ crossover design, thirty-nine participants aged 9–12 years old (29 boys; M(age) = 11 ± 1 years) performed a CDPA and a SPA bout online (via ZOOM) for 15 min. Inhibition (Stroop test) was measured at the baseline, 1 and 30 min following the physical activity (PA) bouts, and self-report measures of affect, mental and physical exertion were taken prior, during and post-PA. Additionally, 31 children took part in semi-structured focus groups to explore the factors affecting their enjoyment. The quantitative results suggest no significant differences on inhibitory responses, affect and physical exertion (all p > 0.05). However, the CDPA induced more mental exertion than the SPA did (p < 0.05). In the focus groups, four themes were identified: physical exertion (e.g., tiredness), social (e.g., teams/groups), environment (e.g., outdoors and competition) and emotional (e.g., fun/enjoyment). Some children (n = 18) reported that the CDPA condition confused them, and to make these activities more interesting and enjoyable, they suggested performing the activities outdoors (n = 15) and including other children as part of a group/team (n = 19). The findings suggest no additional benefit of a cognitively enriched physical activity compared to an SPA bout on the inhibitory responses, affect and enjoyment. Using the instructions provided and given the low cost, the easy administration and the minimal amount of equipment and time involved, either of the approaches may be used in a diversity of contexts (i.e., online, schools or outdoors), and it is worth exploring the effects of these conditions on other aspects of executive function
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