Abrupt vs. gradual visual onsets in go/no-go sustained attention tasks

Two experiments compared both average performance and changes in performance across time in abrupt- and gradual-onset sustained attention tasks. Experiment 1 compared abrupt- and gradual-onset digits. In conditions where the digits onset and offset abruptly and appeared only briefly, similar to typical conditions in the Sustained Attention to Response Task (SART), participants committed more errors on no-go trials and responded faster overall, indicative of a shift in the speed/accuracy tradeoff toward speed. When the digits abruptly onset but remained on-screen for a longer period of time, there were no differences in no-go error rates, hit rates, or reaction time (RT) variability, but participants still emitted faster RTs overall. Experiment 2 compared abrupt- and gradual-onset images. Similar to Experiment 1, abrupt-onset, short-duration images induced more no-go errors and faster RTs, but also more RT variability and reduced hit rates. In the abrupt-onset, long-duration condition, again the only performance difference was a decrease in average RTs. We discuss implications for using these two types of tasks in sustained attention research.

Postextrusion Heating in Three-Dimensional Printing

Stresses result when polymer feed stock is extruded through the nozzle of a three-dimensional (3D) printer, causing undesirable surface roughness called “sharkskin,” which hinders effective bonding to the substrate. A promising method to remove the sharkskin is to reheat the polymer after extrusion. However, questions remain about the appropriate design parameters to guarantee success. A mathematical model is presented for this system, and both amorphous and crystalline polymers are examined. The former is a heat transfer problem; the latter a Stefan problem. Several effectiveness conditions are considered, including exit temperature and a duration condition related to the polymer relaxation time. Our results provide guidance on designing effective postextrusion heaters.

A Review of Ginseng Clinical Trials Registered in the WHO International Clinical Trials Registry Platform

Although ginseng has long been broadly used in clinical settings around the world, few clinical trials on ginseng have been conducted. The objective of this study was to provide a comprehensive evaluation of the characteristics of ginseng clinical trials registered in the WHO International Clinical Trials Registry Platform (ICTRP) as of December 2017 regarding their frequency, design, type of ginseng, dosage, duration, condition, funding sources, and publication status. A total of 134 ginseng clinical studies were registered from 2002 to 2017, of which 60.4% were completed and 23.1% are actively recruiting participants. A large number of trials were associated with aspects of high-quality trial design. Overall, 94% of the trials employed randomized allocation to study arms, 78.4% were double-blind studies using placebo as one of the control groups, and 71% were published as completed trials. Trials whose sample size was restricted to fewer than 100 participants accounted for 74.7% of the total. Of the primary funding sources for ginseng studies, 67.2% were nonindustry organizations. The ginseng clinical trials were heterogeneous with respect to ginseng species and variety, indications, dose, duration, and participant characteristics. Clearly, stricter and methodologically suitable studies are needed to demonstrate the efficacy and safety of ginseng.

The duration of reaching movement is longer than predicted by minimum variance

Whether the central nervous system minimizes variability or effort in planning arm movements can be tested by measuring the preferred movement duration and end-point variability. Here we conducted an experiment in which subjects performed arm reaching movements without visual feedback in fast-, medium-, slow-, and preferred-duration conditions. Results show that 1) total end-point variance was smallest in the medium-duration condition and 2) subjects preferred to carry out movements that were slower than this medium-duration condition. A parsimonious explanation for the overall pattern of end-point errors across fast, medium, preferred, and slow movement durations is that movements are planned to minimize effort as well as end-point error due to both signal-dependent and constant noise.

Kajian Tingkat Kepuasan Pengguna Jasa terhadap Kinerja Pelayanan Angkutan Penyeberangan Lintas Kariangau – Penajam, Balikpapan

The objectives of this study are for knowing costumer satisfaction level of ferry service performance Kariangau– Penajam trajectory, Balikpapan based on customer perception with existence of change of ship operational system from 8:4 (8 ship operated and 4 standby) become 10:2 (10 ship operated and 2 standby) and also for getting alternative solution to overcome problems which there is still after imposed of new ship operational system. This study uses Importance-Performance Analysis (IPA) and Customer Satisfaction Index (CSI)methods. Result of study pursuant to analysis of IPA quadrant, service attributes becoming major priority to be improve repaired by its performance are attribute hygiene of bath room/toilet in ship , accuracy of arrival time in destination port, accuracy of time voyage duration, condition of air circulation in ship and demonstration of usage of safety appliance in ship. CSI calculation result based on customer perception obtained value 69% that representation that assessment of respondent to ferry service performance of Kariangau – Penajam trajectory enter in satisfied category.

Drawing attention to primes increases inhibitory word priming effects.

Inhibitory masked priming effects in the lexical decision task (LDT) have been proven difficult to replicate. If these difficulties are due to individual differences in attention, introducing minor fluctuations in the temporal parameters of prime-target presentation should increase priming effects by drawing attention to the prime. The current study presents two experiments in which we manipulated the duration of prime presentation to this effect. In Experiment 1, we presented subjects (n = 224) with an LDT using form-related and -unrelated word primes. Subjects were assigned to a condition in which all primes were presented for 48ms, or a condition in which one-fourth of the primes were presented for 64ms. Inhibitory priming effects emerged only for the mixed duration condition. Experiment 2 repeated the procedures of the first experiment but with nonword primes. Because nonword primes have no lexical information, target item response latencies should not suffer from the additional processing time required to suppress those representations. Thus, as predicted, Experiment 2 yielded a facilitatory effect of priming. Together, these experiments show that small manipulations of the prime SOA can increase attention to the temporal location of the prime, and that when attention is drawn to the existence of primes in this manner, inhibitory word priming can be observed.

Stability Analysis of High Filling Slope Effected by Precipitation Duration

Aiming at researching on stability of high filling slope effected by precipitation duration. Transient saturated-unsaturated seepage method and slope stability finite element method is combined in this paper. Vadose field of slope is simulated in different precipitation duration condition. On the basis of vadose field author analyses the stability of slope effected by precipitation duration. The research results indicate that change of the pore water pressure is mainly concentrated in the position where the water level changes in the process of precipitation. After the precipitation pore water pressure gradually dissipates. Precipitation duration has great effect on the slope stability. With the precipitation duration increases the slope safety coefficient decreases. The slope safety coefficient decreases in the process of precipitation, but after precipitation, it increases gradually and eventually be more stable. The longer the precipitation duration is, the longer time that the safety coefficient reaches the ultimate stability required.

Comparison of Maximum Tolerated Muscle Torques Produced by 2 Pulse Durations

BackgroundNeuromuscular electrical stimulation (NMES) is an effective therapeutic technique for strengthening weak muscles. A positive dose-response relationship exists between the elicited muscle forces during training and strength (force-generating capacity) gains. Patient discomfort limits NMES muscle forces, potentially compromising efficacy.ObjectiveThe purpose of this study was to compare the NMES muscle torques produced by stimulation trains consisting of 2 different pulse durations.DesignDuring a single testing session, the 2 pulse duration conditions (50 and 200 microseconds) were tested on the opposite lower extremities of the participants.MethodsThe study participants were 10 adults without remarkable medical histories. The maximum tolerated isometric knee extensor torque was the primary dependent variable. The peak currents and phase charges that produced the maximally tolerated torques, as well as the sensory, motor, and pain thresholds for the 2 pulse conditions, were compared.ResultsThe 200-microsecond pulse duration condition resulted in participants tolerating significantly greater muscle torques; it was associated with significantly greater phase charges but significantly lower peak currents.LimitationsThis study only compared muscle torques in response to stimulation trains consisting of pulses with short (50-microsecond) or medium (200-microsecond) durations and did not examine long (∼400- to 600-microsecond) durations. Furthermore, the result of this study may not apply to NMES that uses stimulation patterns other than monophasic, square-wave pulsed current.ConclusionsIt has been suggested that short pulse durations are most appropriate for NMES because they are less likely to recruit nociceptors. The results of this study, however, support the use of a medium pulse duration rather than a short pulse duration when the goal is to produce a maximum torque response from a muscle. These observations may be related to the currents and phase charges for the pain thresholds for the 2 pulse duration conditions.

Task Duration in Contextual Interference

Duration of practice trial on a pursuit rotor task in contextual interference was investigated. Participants practiced at each of 4 angular velocities, with 24 participants completing 28 trials lasting 20 sec., and 24 participants completing 112 trials of 5 sec. Half of the participants in each trial-duration condition practiced in a blocked format and half practiced in a random format. After random practice posttest performance was better than blocked practice when practice-trial duration was 20 sec., but worse when practice-trial duration was 5 sec. This result is not consistent with theoretical explanations of the contextual interference effect and is discussed with reference to the task characteristics and demands of the pursuit rotor.

The Rate of Gain of Perceived Workload in Sustained Attention

Perceived workload was measured via the NASA TLX following a visual vigilance task. Five task durations (10, 20, 30, 40, or 50 min) were combined factorially with two levels of discrimination difficulty (easy, hard) in a between groups design. Detection probability, computed from the final 10 min of watch in each duration condition, varied inversely with signal salience and declined over time. Overall workload varied directly with salience and increased linearly over time. The temporal growth in perceived workload was independent of signal salience. This result suggests that the rate of gain in workload is based upon general features of the vigilance situation rather than specific psychophysical demands such as signal salience.