The Effect of Gaze Position on Reaching Movements in an Obstacle Avoidance Task

Numerous studies have addressed the issue of where people look when they perform hand movements. Yet, very little is known about how visuomotor performance is affected by fixation location. Previous studies investigating the accuracy of actions performed in visual periphery have revealed inconsistent results. While movements performed under full visual-feedback (closed-loop) seem to remain surprisingly accurate, open-loop as well as memory-guided movements usually show a distinct bias (i.e. overestimation of target eccentricity) when executed in periphery. In this study, we aimed to investigate whether gaze position affects movements that are performed under full-vision but cannot be corrected based on a direct comparison between the hand and target position. To do so, we employed a classical visuomotor reaching task in which participants were required to move their hand through a gap between two obstacles into a target area. Participants performed the task in four gaze conditions: free-viewing (no restrictions on gaze), central fixation, or fixation on one of the two obstacles. Our findings show that obstacle avoidance behaviour is moderated by fixation position. Specifically, participants tended to select movement paths that veered away from the obstacle fixated indicating that perceptual errors persist in closed-loop vision conditions if they cannot be corrected effectively based on visual feedback. Moreover, measuring the eye-movement in a free-viewing task (Experiment 2), we confirmed that naturally participants’ prefer to move their eyes and hand to the same spatial location.     

Bioinspired Closed-loop CPG-based Control of a Robot Fish for Obstacle Avoidance and Direction Tracking

This paper presents a study on bioinspired closed-loop Central Pattern Generator(CPG)based control of a robot fish for obstacle avoidance and direction tracking.The biomimetic robot fish is made of a rigid head with a pair of pectoral fins,a wire-driven active body covered with soft skin,and a compliant tail.The CPG model consists of four input parameters:the flapping amplitude,the flapping angular velocity,the flapping offset,and the time ratio between the beat phase and the restore phase in flapping.The robot fish is equipped with three infrared sensors mounted on the left,front and right of the robot fish,as well as an inertial measurement unit,from which the surrounding obstacles and moving direction can be sensed.Based on these sensor signals,the closed-loop CPG-based control can drive the robot fish to avoid obstacles and to track designated directions.Four sets of experiments are presented,including avoiding a static obstacle,avoiding a moving obstacle,tracking a designated direction and tracking a designated direction with an obstacle in the path.The experiment results indicated that the presented control strategy worked well and the robot fish can accomplish the obstacle avoidance and direction tracking effectively.     

Obstacle Avoidance,Visual Detection Performance,and Eye-Scanning Behavior of Glaucoma Patients in a Driving Simulator: A Preliminary Study

The objective of this study was to evaluate differences in driving performance, visual detection performance, and eye-scanning behavior between glaucoma patients and control participants without glaucoma. Glaucoma patients (n = 23) and control participants (n = 12) completed four 5-min driving sessions in a simulator. The participants were instructed to maintain the car in the right lane of a two-lane highway while their speed was automatically maintained at 100 km/h. Additional tasks per session were: Session 1: none, Session 2: verbalization of projected letters, Session 3: avoidance of static obstacles, and Session 4: combined letter verbalization and avoidance of static obstacles. Eye-scanning behavior was recorded with an eye-tracker. Results showed no statistically significant differences between patients and control participants for lane keeping, obstacle avoidance, and eye-scanning behavior. Steering activity, number of missed letters, and letter reaction time were significantly higher for glaucoma patients than for control participants. In conclusion, glaucoma patients were able to avoid objects and maintain a nominal lane keeping performance, but applied more steering input than control participants, and were more likely than control participants to miss peripherally projected stimuli. The eye-tracking results suggest that glaucoma patients did not use extra visual search to compensate for their visual field loss. Limitations of the study, such as small sample size, are discussed.     

连作对丹参生长的障碍效应

通过对1～4年不同连作年限地块丹参生长发育情况进行的连续调查分析,结果表明,连作严重危害丹参生长,主要表现在6～9月,丹参生长期的枯苗率大幅度上升,地上、地下部生长量下降,根系数量、直径和长度减小,产世降低。同时由于有效成分含量降低,根系外观畸形,造成商品率下降,从而影响丹参质量。通过对土壤pH测定发现．丹参连作障碍可能与土壤酸性增加有关。     

太子参连作障碍效应研究

以贵州施秉中药材种植基地连作1～12年的太子参和土壤为试验对象,研究了不同连作年限的太子参生长发育状况、产量、土壤肥力、酶活性、以及土壤微生物等的变化规律,以探讨太子参连作障碍的原因.结果表明:(1)连作严重危害太子参生长发育,随着连作年限的延长,根长、根系数量、株高、茎分支数、结实种子数、总生物量呈下降趋势,产量和单个根重明显降低.连作对太子参地上部的危害最大,连作1～12年地上部生物量极显著下降.(2)连作土壤中总磷、总氮含量增加,速效氮、速效钾、速效磷含量降低,土壤pH值变化微小,有机质变化差异较大;连作土壤微量元素(Cu、Mn、B、Zn、Fe)累积,而钼(Mo)降低甚至缺失.(3)连作地土壤细菌数量减少,放线菌数量呈倒"U"型趋势变化;连作使土壤淀粉酶活性降低,磷酸酶活性呈下降后回升趋势变化,但土壤脲酶活性变化微小.连作使土壤中养分、微生物、酶活性等发生变化,不利于太子参生长,根系微生态失衡可能是太子参连作障碍的主要原因之一.     

Interpretation of Appearance: The Effect of Facial Features on First Impressions and Personality

Appearance is known to influence social interactions, which in turn could potentially influence personality development. In this study we focus on discovering the relationship between self-reported personality traits, first impressions and facial characteristics. The results reveal that several personality traits can be read above chance from a face, and that facial features influence first impressions. Despite the former, our prediction model fails to reliably infer personality traits from either facial features or first impressions. First impressions, however, could be inferred more reliably from facial features. We have generated artificial, extreme faces visualising the characteristics having an effect on first impressions for several traits. Conclusively, we find a relationship between first impressions, some personality traits and facial features and consolidate that people on average assess a given face in a highly similar manner.     

Effect of Influenza Virus Proteins Modulate Hemostasis in vitro and in vivo

We studied the effect of influenza virus proteins—hemagglutinin, neuraminidase, nucleoprotein, and membrane protein—on hemostasis in vitro and in vivo. The results demonstrated that envelope proteins hemagglutinin and neuraminidase enhanced the fibrinolytic and anticoagulant activities of blood plasma and the activity of human tissue plasminogen activator. The membrane protein proved to have the highest activity among the core proteins of influenza virus; in contrast to hemagglutinin and neuraminidase, it inhibited fibrinolysis, increased the coagulant activity of blood plasma, and decreased the activity of human tissue plasminogen activator. The combined action of hemagglutinin and neuraminidase increased the plasma fibrinolytic and anticoagulant activities to a greater extent than the individual action of each agent. The combined action of hemagglutinin and membrane protein also increased the plasma fibrinolytic and anticoagulant activities, although to a lesser extent than the action of hemagglutinin alone. These data indicate that viral proteins are physiologically active and can cause influenza-specific disturbances of hemostasis.     

Differential Avoidance of Snake Odours by a Lizard: Evidence for Prioritized Avoidance Based on Risk

Most studies of predator avoidance behaviours have focussed on single‐predator systems, despite the fact that prey often are confronted with predator rich environments. In the presence of more than one predator, prey may have to choose between avoiding one predator over another. How prey cope with exposure to several enemies simultaneously remains largely untested. In this study I set out to investigate if skinks showed preferential avoidance of snake odours based on the relative predation risk posed by different snake species. This relative predation risk was estimated using information on density, diet specificity and foraging habit of each snake species. I tested retreat‐site selection in two‐choice tests, where lizards chose between different combinations of control and snake treated retreat‐sites as well as two retreat‐sites treated with different snake species odours. Lizards preferred control–treated retreat‐sites to those treated with snake odours and showed a differential avoidance response to refuges treated with odours from different snake species. There was strong evidence to suggest that lizards preferentially avoided refuges with the odours of the snake that posed the greatest predation risk, the white‐lipped snake (Drysdalia coronoides). Naïve juvenile lizards were also tested and their response was similar to the adults demonstrating that the behaviour is innate and not the result of higher encounter rates of more common snake odours. To my knowledge this is one of the first studies to demonstrate that prey can prioritize avoidance to a single most dangerous predator in the face of several predators and conflicting avoidance responses.     

Obesity and Alcohol Modulate the Effect of Apolipoprotein E Polymorphism on Lipids and Insulin

Objective: To assess the interaction between apolipoprotein (apo) E polymorphism, alcohol consumption, and BMI on insulin, lipid, and lipoprotein levels in men. Research Methods and Procedures: Cross‐sectional study of 266 healthy men without hypolipidemic or antidiabetic drug treatment. BMI, apo E polymorphisms, insulin, and lipid and lipoprotein levels were assessed. Alcohol consumption was assessed by questionnaire. ?2/?4 carriers were excluded from the analysis. Results: On bivariate analysis, ?2 carriers had lower levels of total and low‐density lipoprotein cholesterol and higher levels of apo E and lipoparticle B:E than ?3 carriers, the opposite being found for ?4 carriers compared with ?3 carriers; ?4 carriers also had significantly higher insulin levels. On multivariate analysis, significant interactions (p < 0.04) between apo E alleles and increased BMI were found for total and low‐density lipoprotein cholesterol and insulin levels, the increase in those parameters with BMI being stronger among ?4 carriers than among ?3 or ?2 carriers. Significant interactions (p < 0.02) between apo E alleles and alcohol consumption were also found for apo B levels, which increased in ?2 carriers but remained relatively stable in ?3 and tended to decrease in ?4 carriers. Discussion: These data suggest that effects of apo E alleles on lipids and insulin levels are partly dependent on environmental variables such as BMI and alcohol intake. These findings highlight the importance of gene × environment interactions on the deleterious effect of obesity on cardiovascular risk factors.     

The Effect of Visual Features on Jumping Spider Movements Across Gaps

Our objective was to determine whether an animal’s decisions to cross inhospitable open space are influenced by the visual characteristics of targets it can see across the space. We studied jumping spiders (Salticidae) in the genus Phidippus. We considered the effect of target size (short vs. tall) and distance (close vs. distant) in no-choice experiments. How often spiders approached close targets, regardless of target size, was not significantly different from how often they approached tall, distant targets, but they approached close targets of either size significantly more often than short, distant targets. When presented simultaneously with short, close and tall, distant targets the spiders’ choices did not differ significantly from random. We also tested for the effects of the contrast of targets with their background and found that the spiders crossed open space to reach green, but not white, targets, regardless of background. Finally, spiders were more likely to approach a green grass-like target rather than a target composed of geometric shapes. We conclude that target size, distance and appearance all influence the spiders’ willingness to cross open space.     

Responsibility as an Obstacle to Good Policy: The Case of Lifestyle Related Disease

There is a lively debate over who is to blame for the harms arising from unhealthy behaviours, like overeating and excessive drinking. In this paper, I argue that given how demanding the conditions required for moral responsibility actually are, we cannot be highly confident that anyone is ever morally responsible. I also adduce evidence that holding people responsible for their unhealthy behaviours has costs: it undermines public support for the measures that are likely to have the most impact on these harms. I claim that these two facts—the fact that we cannot be highly confident that anyone is morally responsible and the fact that holding people responsible for their unhealthy behaviours has costs—interact. Together they give us a powerful reason for believing, or acting as if we believed, that ordinary people are not in fact responsible for their unhealthy behaviours.     

Temperament Traits and Chronic Pain: The Association of Harm Avoidance and Pain-Related Anxiety

Objective

Anxiety symptoms are common in chronic pain patients. High levels of anxiety are associated with increased pain experience and disability. Proneness to anxiety has a large interindividual variation. The aim of the study was to determine whether the anxiety-related temperament trait Harm Avoidance (HA), is associated with pain-related anxiety.

Methods

One hundred chronic pain patients in a multidisciplinary pain clinic participated in the study. The patients were assessed using the HA scale of the Temperament and Character Inventory (TCI) of Cloninger and Pain Anxiety Symptoms Scale-20 (PASS-20). Both the HA total score and the four subscales of HA were analyzed. Current pain intensity was measured using the Visual Analogue Scale (VAS). The Beck Depression Inventory (BDI) was used to control for the influence of depression on the personality measurement.

Results

The HA total score was associated with PASS-20, but the association became non-significant after controlling for depression. The HA4 Fatigability subscale was associated with the PASS scales. Depression did not influence this association. Pain intensity was not correlated with HA or the PASS scales. However, the association between HA4 Fatigability and PASS was influenced by pain intensity. Higher pain intensity was associated with stronger association between the scales.

Conclusion

Harm Avoidance, representing temperament and trait-related anxiety, has relevance in pain-related anxiety. Assessing personality and temperament may deepen the clinician''s understanding of the pain experience and behavior in chronic pain patients.     

The Effect of Approach/Avoidance Training on Alcohol Consumption Is Mediated by Change in Alcohol Action Tendency

Training people to respond to alcohol images by making avoidance joystick movements can affect subsequent alcohol consumption, and has shown initial efficacy as a treatment adjunct. However, the mechanisms that underlie the training’s efficacy are unknown. The present study aimed to determine 1) whether the training’s effect is mediated by a change in action tendency or a change in selective attention, and 2) whether the training’s effect is moderated by individual differences in working memory capacity (WMC). Three groups of social drinkers (total N = 74) completed either approach-alcohol training, avoid-alcohol training or a sham-training on the Approach-Avoidance Task (AAT). Participants’ WMC was assessed prior to training, while their alcohol-related action tendency and selective attention were assessed before and after the training on the recently developed Selective-Attention/Action Tendency Task (SA/ATT), before finally completing an alcohol taste-test. There was no significant main effect of approach/avoidance training on alcohol consumption during the taste-test. However, there was a significant indirect effect of training on alcohol consumption mediated by a change in action tendency, but no indirect effect mediated by a change in selective attention. There was inconsistent evidence of WMC moderating training efficacy, with moderation found only for the effect of approach-alcohol training on the AAT but not on the SA/ATT. Thus approach/avoidance training affects alcohol consumption specifically by changing the underlying action tendency. Multiple training sessions may be required in order to observe more substantive changes in drinking behaviour.