Definition of spatial positions within foraging Greater White-fronted Geese flocks from an individual's perspective:Cost-benefit dynamics change with the distance to flock edge

The costs and benefits of group living are not evenly distributed among individuals that occupy different spatial positions within a group(central or peripheral).However,the definitions of central and peripheral positions may artificially mask the true dynamics of cost and benefit of individuals.Using wintering foraging Greater Whitefronted Geese(Anser albifrons)flocks as our study system,we measured individual spatial position within a flock as distance to the flock edge.First,we tested the effects of distance to edge on the antipredation cost and foraging benefit of individual goose using generalized linear mixed models(GLMMs).Flock size and number of neighbors and their interactions with distance to edge were included as fixed effects in GLMMs.Then we used piecewise regression to determine the threshold value of distance to edge to classify central and peripheral individuals.Our results indicated distance to edge significantly affected percent of time spent on vigilance(vigilance time),percent of time spent on foraging(foraging time)and intake rate(pecks/min),whereas other factors had no effects.We found that the critical distance that predicted changes in behavior was around 2.5 m.Birds 2.5 m or less from the edge of the group were more vigilant,and had less efficient foraging than more central individuals.Behavioral differences between central and peripheral individuals were more easily detected when the birds were classified by the method introduced in this study than by the traditional minimum convex polygon method.Our research provides researchers a dichotomous classification scheme that places individuals into peripheral and central positions from an individual's perspective.

Effects of microtopography on spatial point pattern of forest stands on the semi-arid Loess Plateau,China

Microtopography may affect the distribution of forests through its effect on rain redistribution and soil water distribution on the semi-arid Loess Plateau,China.In this study,we investigated the characteristics of microtopography on two shady slopes（slope A,5 hm2,uniform slope;slope B,5 hm2,microtopography slope） and surveyed the height,the diameter at breast height and the location（x,y coordinates） of all selected individual trees（Robinia pseudoacacia Linn.,Pyrus betulifolia Bunge,Populus hopeiensis Hu ＆ Chow,Armeniaca sibirica Lam.,Populus simonii Carr.and Ulmus pumila Linn.） on slope A and slope B in the watersheds of Wuqi county,Shaanxi province.Subsequently,the effects of microtopography on the spatial pattern of forest stands were analyzed using Ripley＇s K（r） function.The results showed that：（1） The maximal aggregation radiuses of the tree species on the uniform slope（slope A） were larger than 40 m,whereas those of the tree species on the microtopography slope（slope B） were smaller than 30 m.（2） On slope B,the spatial association of R.pseudoacacia with P.betulifolia,A.sibirica,P.simonii and U.pumila varied from being strongly negative to positive at microtopography scales.The spatial association of Populus hopeiensis Hu ＆ Chow with U.pumila also varied from being strongly negative to positive at microtopography scales.However,there was no spatial association between P.betulifolia and P.hopeiensis,P.betulifolia and A.sibirica,P.betulifolia and P.simonii,P.betulifolia and U.pumila,P.hopeiensis and A.sibirica,P.hopeiensis and P.simonii,A.sibirica and P.simonii,A.sibirica and U.pumila,and P.simonii and U.pumila.On slope A,the spatial association between tree species were strongly negative.The results suggest that microtopography may shape tree distribution patterns on the semi-arid Loess Plateau.

MVCE-Net: Multi-View Region Feature and Caption Enhancement Co-Attention Network for Visual Question Answering

Visual question answering(VQA)requires a deep understanding of images and their corresponding textual questions to answer questions about images more accurately.However,existing models tend to ignore the implicit knowledge in the images and focus only on the visual information in the images,which limits the understanding depth of the image content.The images contain more than just visual objects,some images contain textual information about the scene,and slightly more complex images contain relationships between individual visual objects.Firstly,this paper proposes a model using image description for feature enhancement.This model encodes images and their descriptions separately based on the question-guided coattention mechanism.This mechanism increases the feature representation of the model,enhancing the model’s ability for reasoning.In addition,this paper improves the bottom-up attention model by obtaining two image region features.After obtaining the two visual features and the spatial position information corresponding to each feature,concatenating the two features as the final image feature can better represent an image.Finally,the obtained spatial position information is processed to enable the model to perceive the size and relative position of each object in the image.Our best single model delivers a 74.16%overall accuracy on the VQA 2.0 dataset,our model even outperforms some multi-modal pre-training models with fewer images and a shorter time.

Collective decision-making and spatial patterns in orientation of an endemic ungulate on the Tibetan Plateau

Group living animals form striking aggregation patterns and display synchronization,polarization,and collective intelligence.Though many col-lective behavioral studies have been conducted on small animals like insects and fish,research on large animals is still rare due to the limited availability of field collective data.We used drones to record videos and analyzed the decision-making and behavioral spatial patterns in orienta-tion of Kiang(Tibetan wild ass,Equus kiang).Leadership is unevenly distributed among Kiang,with the minority initiating majority behavior-shift decisions.Decisions of individual to join are driven by imitation between group members,and are largely dependent on the number of members who have already joined.Kiang respond to the behavior and position of neighbors through different strategies.They strongly polarize when moving,therefore adopting a linear alignment.When vigilant,orientation deviation increases as they form a tighter group.They remain scattered while feeding and,in that context,adopt a side-by-side alignment.This study reveals partially-shared decision-making among Kiang,whereby copying neighbors provides the wisdom to thrive in harsh conditions.This study also suggests that animals'spatial patterns in orientation depend largely ontheirbehavioral states inachieving synchronization.

A position sensor based on grating projection with spatial filtering and polarization modulation

A position sensor based on grating projection with spatial filtering and polarization modulation is presented. A grating is projected onto the object to be measured through a 4f optical system with a spatial filter. After reflected by the object, the grating projection is imaged on a detection grating through another 4f optical system to form moiré fringes, The polarization modulated moiré signal is detected to obtain the position information of the object. In the position sensor, the moiré signal varies sinusoidally with the position of object. The measurement is independent of the incident intensity on the projection grating and the reflectivity of the object to be measured, In experiments, the effectiveness of the position sensor is proved, and the root mean square （RMS） error at each measurement position is less than 13 nm.

Parental dependence on the nest's spatial cues in offspring recognition decreases with nestling growth in the azure-winged magpie

In altricial birds,to address which cues are used by parents to recognize their offspring,and when they switch between cues during reproduction,it has not been well determined.In this study,we address this questi on in a Tibetan populatio n of the azure-winged magpie Cyanopica cyan us f by examining the dependence of parents on a nest's spatial position in offspring recognition.During the egg and nestling phases,azure-winged magpie nests were translocated to new positions across various distances from their original site,and parental responses to the translocated nests were investigated.Our findings show that a nesfs spatial position is not connected with the survival of its young,but might be used as a cue in parental offspring recognition.When nests are translocated to a new position within a certain distance,parents could recognize their nests and returned to resume their parenting behaviors.Parental dependence on the nest's spatial position in offspring recognition is higher during the egg phase than during the nestling phase,and it decreases with the growth of nestlings.After nestlings reach a certain age,the nest's spatial position was no longer used by pare nts as the single cue for offspring recog nition.These findings suggest that azure-winged magpies switch their cues in offspring recog nition during the differe nt stages of reproduction.After parent-offspring communication has been established,the offspring's phenotypic traits may become a more reliable cue than the nests spatial position in offspring recognition.