Bioinformatic Analysis Reveals both Oversampled and Underexplored Biosynthetic Diversity in Nonribosomal Peptides.

The traditional natural product discovery approach has accessed only a fraction of the chemical diversity in nature. The use of bioinformatic tools to interpret the instructions encoded in microbial biosynthetic genes has the potential to circumvent the existing methodological bottlenecks and greatly expand the scope of discovery. Structural prediction algorithms for nonribosomal peptides (NRPs), the largest family of microbial natural products, lie at the heart of this new approach. To understand the scope and limitation of the existing prediction algorithms, we evaluated their performances on NRP synthetase biosynthetic gene clusters. Our systematic analysis shows that the NRP biosynthetic landscape is uneven. Phenylglycine and its derivatives as a group of NRP building blocks (BBs), for example, have been oversampled, reflecting an extensive historical interest in the glycopeptide antibiotics family. In contrast, the benzoyl BB, including 2,3-dihydroxybenzoate (DHB), has been the most underexplored, hinting at the possibility of a reservoir of as yet unknown DHB containing NRPs with functional roles other than a siderophore. Our results also suggest that there is still vast unexplored biosynthetic diversity in nature, and the analysis presented herein shall help guide and strategize future natural product discovery campaigns. We also discuss possible ways bioinformaticians and biochemists could work together to improve the existing prediction algorithms.

Traffic and Environmental Cues and Slow-Down Behaviors in Virtual Driving.

This study used a driving simulator to investigate whether the presence of pedestrians and traffic engineering designs that reported to have reduction effects on overall traffic speed at intersections can facilitate drivers adopting lower impact speed behaviors at pedestrian crossings. Twenty-eight men (M age = 39.9 yr., SD = 11.5) with drivers' licenses participated. Nine studied measures were obtained from the speed profiles of each participant. A 14-km virtual road was presented to the participants. It included experimental scenarios of base intersection, pedestrian presence, pedestrian warning sign at intersection and in advance of intersection, and perceptual lane narrowing by hatching lines. Compared to the base intersection, the presence of pedestrians caused drivers to slow down earlier and reach a lower minimum speed before the pedestrian crossing. This speed behavior was not completely evident when adding a pedestrian warning sign at an intersection or having perceptual lane narrowing to the stop line. Additionally, installing pedestrian warning signs in advance of the intersections rather at the intersections was associated with higher impact speeds at pedestrian crossings.

Differences in cognitive process-related skills between taxi and non-taxi drivers between 50 and 70 years old.

This study investigated differences between 50- to 70-yr.-old taxi and non-taxi drivers with respect to cognitive process-related skills. Psychological indicators associated with perceptuomotor, attentional, and spatial memory recall abilities were collected for 173 taxi drivers (7 women, 166 men; M age = 57.5 yr.) and 175 non-taxi drivers (85 women, 90 men; M age = 58.2 yr.). The taxi drivers had shorter reaction times and motor times in response to stimuli in simple stimulus-response tasks. There was an age-related decline in monocular vision detection on both sides, processing speed for fovea stimuli, and higher-level cognition for drivers. Accordingly, the frontal visual information processing speed of the taxi drivers was superior to the non-taxi drivers, but a distinct age-related decline was observed for all drivers.

The use of a quasi-naturalistic riding method to investigate bicyclists' behaviors when motorists pass.

The present study aimed to investigate how motorized vehicle-related factors, road-related factors, and bicyclist-related factors influenced motorists' decisions about initial passing distances and bicyclists' behaviors after the motorists started to pass. A quasi-naturalistic riding method was used for thirty-four participating bicyclists riding an instrumented bicycle in real traffic. The study included 1380 incidents of left-side passing by motorists and revealed that the factors studied influenced both the motorists' initial passing distance and the bicyclists' position (lateral distance from the passing motorists), wheel angle, and speed control behaviors while the motorists passed. Some factors were related to the motorized vehicles; for example, the initial passing distance and the mean lateral distances were smaller when motorcycles passed than when cars and small trucks passed. The bicyclists demonstrated weaker lateral stability when they were passed by buses. In addition, a longer passing time caused the bicyclists to demonstrate cautious but less stable riding behaviors. For road-related factors, a clear and longitudinal solid line separation helped to maintain a greater lateral distance between motorists and bicyclists and assist the bicyclists in riding out of the motorists' path, maintaining a low speed, and remaining stable. Moreover, when bicyclists avoided road surface hazards, they reduced the initial passing distances that the motorists had chosen. Considering bicyclist-related factors, the motorists selected a greater initial passing distance for female bicyclists. There were also gender differences related to the bicyclists' lateral control, and differences in road use experience may explain this gender difference. Furthermore, the bicyclists' wheel angle, speed, and speed variation affected the motorists' initial passing distance. The present study demonstrated that the quasi-naturalistic riding method is capable of collecting rich data concerning bicyclists' behaviors, which could potentially be utilized in various types of studies. However, this method requires a large sample and considerable time and effort for data processing.

The use of mouse and one- and two-finger input methods for searching a large, horizontal display.

A horizontal, table-sized computer display was used to examine one- and two-finger search performances. 31 college students participated in a basic computer operation and target landmark search task. The mean completion times of the target landmark search task were analyzed by a repeated-measures analysis of variance with the following factors: input device, environmental familiarity, and cue. Compared to the mouse, directly touching the computer display with one finger was inefficient when the task required more precise human-computer interactions, such as selecting small objects, or complicated tasks such as searching for targets in a computerized geographic application. However, directly touching the computer display with two fingers, one finger of each hand, appears efficient in complicated tasks. Additionally, familiar and cued environments can aid in the target landmark search task especially when searching within the cued conditions. However, the unfavorable effect of using a one-finger touch technique in searching may eliminate such cue effects.

Effect of visual-verbal load and spatial compatibility on stimulus response.

This study examined the effects of visual-verbalload (as measured by a visually presented reading-memory task with three levels) on a visual/auditory stimulus-response task. The three levels of load were defined as follows: "No Load" meant no other stimuli were presented concurrently; "Free Load" meant that a letter (A, B, C, or D) appeared at the same time as the visual or auditory stimulus; and "Force Load" was the same as "Free Load," but the participants were also instructed to count how many times the letter A appeared. The stimulus-response task also had three levels: "irrelevant," "compatible," and "incompatible" spatial conditions. These required different key-pressing responses. The visual stimulus was a red ball presented either to the left or to the right of the display screen, and the auditory stimulus was a tone delivered from a position similar to that of the visual stimulus. Participants also processed an irrelevant stimulus. The results indicated that participants perceived auditory stimuli earlier than visual stimuli and reacted faster under stimulus-response compatible conditions. These results held even under a high visual-verbal load. These findings suggest the following guidelines for systems used in driving: an auditory source, appropriately compatible signal and manual-response positions, and a visually simplified background.

Measurement of auditory cues in drivers' distraction.

A driving simulator was used to examine the effects on driving performance of auditory cues in an in-vehicle information search task. Drivers' distraction by the search tasks was measured on a peripheral detection task. The difficulty of the search task was systematically varied to test the distraction caused by a quantified visual load. 58 participants completed the task. Performance on both search tasks and peripheral detection tasks was measured by mean response time and percent error. Analyses indicated that in-vehicle information search performance can be severely degraded when a target is located within a group of diverse distractors. Inclusion of an auditory cue in the visual search increased the mean response time as a result of a change in modality from auditory to visual. Inclusion of such an auditory cue seemed to influence distraction as measured by performance on the peripheral detection task; accuracy was lower when auditory cues were provided, and responses were slower when no auditory cues were provided. Distraction by the auditory cue varied according to the difficulty of the search task.

Evidence for the selective attention mechanism and dual-task interference.

In order to explore the selective attention mechanism and the dual-task information-processing model, two experiments were carried out involving a visual search task and a visual detection task. The results showed that the early period of attention selection is controlled in a bottom-up manner. With respect to the dual-task information-processing model, the results showed that the central information-processing model would include a sequence model for tasks that use the same perception resource, causing a bottleneck in information processing. Our study suggests that a simple and prominent signal could be used to attract drivers' attention prior to the emergent events. Moreover, any human-machine interface design in driving-associated systems should consider this information-processing bottleneck. With respect to signal type, targeted and easy to categorize were two useful elements to consider.