Individual heterogeneity influences the effects of translocation on urban dispersal of an invasive reptile

Background Invasive reptiles pose a serious threat to global biodiversity, but early detection of individuals in an incipient population is often hindered by their cryptic nature, sporadic movements, and variation among individuals. Little is known about the mechanisms that affect the movement of these species, which limits our understanding of their dispersal. Our aim was to determine whether translocation or small-scale landscape features affect movement patterns of brown treesnakes (Boiga irregularis), a destructive invasive predator on the island of Guam. Methods We conducted a field experiment to compare the movements of resident (control) snakes to those of snakes translocated from forests and urban areas into new urban habitats. We developed a Bayesian hierarchical model to analyze snake movement mechanisms and account for attributes unique to invasive reptiles by incorporating multiple behavioral states and individual heterogeneity in movement parameters. Results We did not observe strong differences in mechanistic movement parameters (turning angle or step length) among experimental treatment groups. We found some evidence that translocated snakes from both forests and urban areas made longer movements than resident snakes, but variation among individuals within treatment groups weakened this effect. Snakes translocated from forests moved more frequently from pavement than those translocated from urban areas. Snakes translocated from urban areas moved less frequently from buildings than resident snakes. Resident snakes had high individual heterogeneity in movement probability. Conclusions Our approach to modeling movement improved our understanding of invasive reptile dispersal by allowing us to examine the mechanisms that influence their movement. We also demonstrated the importance of accounting for individual heterogeneity in population-level analyses, especially when management goals involve eradication of an invasive species.

Multidimensional cerebellar computations for flexible kinematic control of movements

Both the environment and our body keep changing dynamically. Hence, ensuring movement precision requires adaptation to multiple demands occurring simultaneously. Here we show that the cerebellum performs the necessary multi-dimensional computations for the flexible control of different movement parameters depending on the prevailing context. This conclusion is based on the identification of a manifold-like activity in both mossy fibers (MF, network input) and Purkinje cells (PC, output), recorded from monkeys performing a saccade task. Unlike MFs, the properties of PC manifolds developed selective representations of individual movement parameters. Error feedback-driven climbing fiber input modulated the PC manifolds to predict specific, error type-dependent changes in subsequent actions. Furthermore, a feed-forward network model that simulated MF-to-PC transformations revealed that amplification and restructuring of the lesser variability in the MF activity is a pivotal circuit mechanism. Therefore, flexible control of movement by the cerebellum crucially depends on its capacity for multi-dimensional computations.

DESIGN AND EXPERIMENTAL STUDY OF FLEXIBLE THRESHING UNIT FOR CHINESE CABBAGE SEEDS

In order to solve the problems of low efficiency of artificial harvesting method and high breakage rate and undepurated rate of traditional threshing method, a new flexible threshing device of Chinese cabbage seeds was designed, which was composed of flexible round head nail teeth and circular tube concave plate. Hertz contact collision theory was used to analyze and determine the structural parameters of the new threshing unit. The interaction force of different threshing elements materials were analyzed by using EDEM. The feasibility of the flexible threshing unit was verified by the comparison test of the distribution of threshed mixture. Finally, the orthogonal test was carried out to study the influence of the movement parameters of each structure on the cleaning rate and the rate of undepurated, and the weight matrix method was used to optimize it. The results indicate that under the condition the rotating speed of the threshing cylinder 750 rpm, the concave clearance 20 mm, and the feeding rate 1.4 kg/s, the threshing performance of the flexible threshing unit was the best. At this time, the breaking rate was 0.064%, and the un-threshing rate was 0.67%, which both met the relevant industry standards.

LAND UNMANNED COMPLEX WITH PASSIVE RANGE MEASUREMENT

The automatic robotic complex will obviously become one of the main subjects in the conduct of military actions in the near future. To control movement parameters, as well as search, target detection and aiming, the complex includes a technical vision system. The minimum sufficient configuration of such a system includes a television search camera with a wide field of view, television and thermal imaging sights, and a rangefinder. The use of laser rangefinders ensures high accuracy of aiming weapons, but generates a powerful unmasking feature. To ensure the secrecy of the functioning of the robotic complex, range finders can operate in a passive mode using information from on-board television cameras. But at the same time, the metrological characteristics of the information measuring channel are significantly deteriorated. Accuracy of five methods of passive distance measurement with application of TV-systems of land unmanned complex is assessed in paper. Classic method of TV-sight external-base range-finder with scale, designed on human height 1,65 m, is ensuring measurement accuracy 135 m on distance 1000 m. External base method, when a range finger scale is forming on remote display as variable length vertical line in process of target framing, is ensuring measurement accuracy 100,3 m on dis-tance 1000 m. Fixed-base range-finder method, when distance between entrance pupils of TV-sight and wide viewing field camera using as base, is ensuring measurement accuracy 76 m on distance 1000 m. Distance measurement method due to displacement of land unmanned complex ensures a measurement accuracy up to 168 m on distance 1000 m. Measurement method due to using zoom-objective is not suitable for land unmanned complex. Proposals have been formulated for the spatial layout of the computer vision system, in which the method of the fixed-base rangefinder is implemented, which ensures the highest measurement accuracy.

Graphological and semantic foregrounding as affecting gaze and speech of impulsive and reflective readers

The study explores the effects of graphological and semantic foregrounding on speech and gaze behavior in textual information construal of subjects with higher and lower impulsivity. Eye movements of sixteen participants were recorded as they read drama texts with interdiscourse switching (semantic foregrounding), with features of typeface distinct from the surrounding text (graphological foregrounding). Discourse modification patterns were analyzed and processed in several steps: specification of participant/object/action/event/perspective modification, parametric annotation of participants’ discourse responses, contrastive analysis of modification parameter activity and parameter synchronized activity. Significant distinctions were found in eye movement parameters (gaze count and initial fixation duration) in subjects with higher and lower impulsivity when reading parts of text with graphical foregrounding. Impulsive subjects tended to visit the areas more often with longer initial fixations than reflective subjects, which is explained in terms of stimulus-driven attention, associated with bottom-up processes. However, these differences in gaze behavior did not result in pronounced distinctions in discourse responses, which were only slightly mediated by impulsivity/reflectivity.

Investigation of the Required Discreteness of Interpolation Movement Parameters in Cyber-physical Systems

Improving the accuracy, reliability, and performance of cyber-physical systems such as high-speed machining, laser cutting, welding and cladding etc. is one of the most pressing challenges in modern industry. CNC system carries out data processing and significantly affect on accuracy of operation such equipment. The paper considers the problem of controlled axes motion differential characteristics data processing in the internal representation of the discrete space of the CNC system. Equations for determining the required discreteness of the differential characteristics position and resolution, such as the speed, acceleration, and jerk are proposed. For the most widely used CNC equipment specific discreteness and resolution values have been determined.

Eye Movement Abnormalities in Amyotrophic Lateral Sclerosis

Background and Purpose It is generally believed that eye movements are completely spared in amyotrophic lateral sclerosis (ALS). Although a series of eye movement abnormalities has been recognized in recent years, the findings are highly controversial, and the corresponding pattern has not yet been established. Furthermore, bulbar disabilities should be considered in relation to eye movement abnormalities. The present study aimed to determine whether eye movement abnormalities are present in ALS and, if so, to investigate their characteristics and their association with bulbar disability in ALS patients. Methods Patients with clinically definite, probable or laboratory-supported probable ALS (n=60) and a control group composed of their caregivers (n=30) underwent clinical assessments and standardized evaluations of the oculomotor system using videonystagmography. The gaze test, reflexive saccade test and smooth pursuit test were administered to all subjects. Results Eye movement abnormalities such as square-wave jerks, abnormal cogwheeling during smooth pursuit, and saccade hypometria were observed in ALS patients. Square-wave jerks (p<0.001) and abnormal cogwheeling during smooth pursuit (p=0.001) were more frequently observed in ALS patients than in the control subjects. In subgroup analyses, square-wave jerks (p=0.004) and abnormal cogwheeling during smooth pursuit (p=0.031) were found to be more common in ALS patients with bulbar involvement (n=44) than in those without bulbar involvement (n=16). There were no significant differences in the investigated eye movement parameters between bulbar-onset (n=12) and spinal-onset patients (n=48). Conclusion ALS patients showed a range of eye movement abnormalities, affecting mainly the ocular fixation and smooth pursuit systems. These abnormalities were observed more common in the ALS patients with bulbar involvement. Our pioneering study indicates that the region of involvement could better indicate the pathophysiological essence of the abnormalities than the type of onset pattern in ALS. Eye movement abnormalities may be potential clinical markers for objectively evaluating upper brainstem or supratentorial cerebral lesion neurodegeneration in ALS.

The Influence of Articulatory Suppression on Reading Among Chinese Children With Developmental Dyslexia: An Eye-Movement Study

Objective: The study aimed to examine how the phonological loop influences reading ability and processing in Chinese children with developmental dyslexia (DD).Methods: This study included 30 children with DD and 37 children without DD. Two types of articles (i.e., scenery prose and narrative story) and two conditions (under the conditions of articulatory-suppression and silent reading) were applied. An eye-link II High-Speed Eye Tracker was used to track a series of eye-movement parameters. The data were analyzed by the linear Mixed-Effects model.Results: Compared with children without DD, Children with DD had lower reading achievement (RA), frequency of saccades (FS) and frequency of fixations (FF), longer reading time (RT) and average fixation duration (AFD), slower reading speed (RS), shorter average saccade amplitude (ASA) and fixation distance (FD), more number of fixations (NF), and number of saccades (NS). There were significant interactions between participant group and articulatory suppression on RT and FD. We also observed interaction effects between article types and articulatory suppression on RA, AFD, ASA, and FS.Conclusion: Children DD exhibit abnormal phonological loop and eye movements while reading. The role of articulatory suppression on reading varies with the presentation of DD and the article type.

Human gait modelling and tracking based on motion functionalisation

This paper proposes a mathematical function movement model based on the gait movement of the human body and, in particular, on the trajectory of the limbs during human movement. The article systematically measures and experimentally deals with the trajectory of the limbs of 40 students in the walking movement. The linear high-order polynomial fitting method eliminates the motion error. Simultaneously, the linear relationship least square method is used to obtain the expression of the limb motion function. Finally, the mathematical model of the limb motion trajectory is obtained. It is verified through experiments that the model proposed in the thesis can calculate the law of limb movement and movement parameters of any person under normal walking movement. This research has high research value for human movement rehabilitation and the design of wearable equipment.

Saccadic Eye Movements in Elderly Depressed Patients With Suicidal Behaviors: An Exploratory Eye-Tracking Study

Suicidal behaviors (SBs) are often associated with impaired performance on neuropsychological executive functioning (EF) measures that encourage the development of more specific and reliable tools. Recent evidence could suggest that saccadic movement using eye tracking can provide reliable information on EF in depressive elderly. The aim of this study was to describe oculomotor performances in elderly depressed patients with SB. To achieve this aim, we compared saccadic eye movement (SEM) performances in elderly depressed patients (N = 24) with SB and with no SB in prosaccade (PS) and antisaccade (AS) tasks under the gap, step, and overlap conditions. All participants also underwent a complete neuropsychological battery. Performances were impaired in patients with SB who exhibited less corrected AS errors and longer time to correct them than patients with no SB. Moreover, both groups had a similar performance for PS latencies and correct AS. These preliminary results suggested higher cognitive inflexibility in suicidal patients compared to non-suicidal. This inflexibility may explain the difficulty of the depressed elderly in generating solutions to the resurgence of suicidal ideation (SI) to respond adequately to stressful environments. The assessment of eye movement parameters in depressed elderly patients may be a first step in identifying high-risk patients for suicide.