All-optical driven soft crawler with complexmotion capabilities

The emergence of millimeter-scale soft actuators has signifi-cantly expanded the potential applications in areas such as search and rescue,drug delivery,and human assistance,due to their high flexibility.Despite these advancements,achieving precise control over the intricate movements of soft crawlers poses a significant challenge.In this study,we have developed an all-optical approach that enables manipulation of propul-sive forces by simultaneously modifying the magnitude and direction of friction forces,thereby enabling complex motions of soft actuators.Importantly,the approach is not constrained by specific actuator shapes,and theoretically,any elongated photothermal actuator can be employed.The actuator was designed with an isosceles trapezoid shape,featuring a top width of 2mm,a bottom width of 4 mm,and a length of 8 mm.Through our,manipulation approach,we showcase a proof-of-concept for complex soft robotic motions,including crawling(achieving speeds of up to 2.25 body lengths per minute),turning,avoiding obstacles,handling and trans-ferring objects approximately twice its own weight,and navi-gating narrow spaces along programmed paths.Our results showcasethis all-optical manipulationapproach as a promising,yet unexplored tool for the precision and wireless control for the development of advanced soft actuators.

亲缘选择在植物从营养分配向繁殖分配转变中的潜在作用

根据经典的最优繁殖分配理论,植物生长过程中从营养生长向繁殖分配的转变是突然发生的。一些植物确实如此,这也是农作物产量最大化的一种有效策略。然而,自然界很多植物从营养生长向繁殖分配的转变是渐进发生的。一些修正的生物量分配理论也预测了这种渐变趋势。本研究假设亲缘选择能够改变最优分配理论的预测。通过数学模型,我们研究了正负亲缘选择对植物向繁殖器官分配能量起始时间的影响。基于代价与收益的合理假设,当繁殖器官与营养器官起始生物量比值较高时,处于亲缘选择作用下的植物更可能以一种突变的方式实现从营养生长向繁殖生长的转变。经验数据的观测支持我们的理论预测。这一研究在连接植物生活史与能量分配以及提高农业产量方面具有重要意义。

Advantages and Disadvantages of Rotating Spatial Closures for Managing Fisheries

Marine protected areas are becoming an increasingly important tool in fisheries management.Particularly for species with relatively sedentary adults,the basic approach taken is to permanently close areas to fishing,which allows species to recover inside the reserve and export larvae to outside of it that can eventually be harvested.Two key issues posed are ensuring the movement of larvae outside the reserve to support fisheries and the sociological and economic impact of marine reserves.An alternative approach that addresses these issues is rotational zoning systems,which have been implemented for some fisheries.What has been missing is an analysis of the relative impact of marine reserves versus rotational zoning systems on fisheries yields that could be used to provide important principles to guide management.Using a simplified model with clear assumptions,we show that rotational zoning systems are inferior in fisheries management targeting low-fecundity species or species with a low proliferation rate,especially when the fraction of the coastline protected is relatively small(approximately less than 20%)and the rotational fraction results in landings far below optimal fisheries yields.These results are tested with hypothetical species,providing quantitative guidelines in cases where decisions must be made with limited data as well as a framework for more detailed analyses in cases where more data are available.

Ecogeographical variation of 12 morphological traits within Pinus tabulaeformis: the effects of environmental factors and demographic histories

Aims More data are needed about how genetic variation(GV)and envi-ronmental factors influence phenotypic variation within the natural populations of long-lived species with broad geographic distribu-tions.To fill this gap,we examined the correlations among envi-ronmental factors and phenotypic variation within and among 13 natural populations of Pinus tabulaeformis consisting of four demo-graphically distinct groups within the entire distributional range.Methods Using the Akaike’s information Criterion(AiC)model,we measured 12 morphological traits and constructed alternative candidate models for the relationships between each morphological trait and key climatic variables and genetic groups.We then compared the AiC weight for each candidate model to identify the best approximating model for ecogeographical variation of P.tabulaeformis.The partitioning of vari-ance was assessed subsequently by evaluating the independent vari-ables of the selected best models using partial redundancy analysis.Important Findings Significant phenotypic variation of the morphological traits was observed both within individual populations and among populations.Variation partition analyses showed that most of the phenotypic variation was co-determined by both GV and climatic factors.GV accounted for the largest proportion of reproductive trait variation,whereas local key climatic factors(i.e.actual evapotranspiration,AET)accounted for the largest proportion of phenotypic variation in the remaining investigated traits.Our results indicate that both genetic divergence and key environmental factors affect the phenotypic variation observed among populations of this species,and that reproductive and vegetative traits adaptively respond differently with respect to local environmental conditions.This partitioning of factors can inform those making predictions about phenotypic variation in response to future changes in climatic conditions(particularly those affecting AET).