Optimal Gait for Bioinspired Climbing Robots Using Dry Adhesion:A Quasi-Static Investigation

Legged robots relying on dry adhesives for vertical climbing are required to preload their feet against the wall to increase contact surface area and consequently maximize adhesion force. Preloading a foot causes a redistribution of forces in the entire robot, including contact forces between the other feet and the wall. An inappropriate redistribution of these forces can cause irreparable detachment of the robot from the vertical surface. This paper investigates an optimal preloading and detaching strategy that minimizes energy consumption, while retaining safety, during locomotion on vertical surfaces. The gait of a six-legged robot is planned using a quasi-static model that takes into account both the structure of the robot and the characteristics of the adhesive material. The latter was modelled from experimental data collected for this paper. A constrained optimization routine is used, and its output is a sequence of optimal posture and motor torque set-points.     

A cortico-basal ganglia-thalamo-cortical channel underlying short-term memory

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Climate change, connectivity and conservation decision making: back to basics

1.  The challenge of climate change forces us to re-examine the assumptions underlying conservation planning.
2.  Increasing 'connectivity' has emerged as the most favoured option for conservation in the face of climate change.
3.  We argue that the importance of connectivity is being overemphasized: quantifying the benefits of connectivity per se is plagued with uncertainty, and connectivity can be co-incidentally improved by targeting more concrete metrics: habitat area and habitat quality.
4.   Synthesis and applications . Before investing in connectivity projects, conservation practitioners should analyse the benefits expected to arise from increasing connectivity and compare them with alternative investments, to ensure as much biodiversity conservation and resilience to climate change as possible within their budget. Strategies that we expect to remain robust in the face of climate change include maintaining and increasing the area of high quality habitats, prioritizing areas that have high environmental heterogeneity and controlling other anthropogenic threatening processes.     

Strategic planning for instream flow restoration: a case study of potential climate change impacts in the central Columbia River basin

We provide a case study prioritizing instream flow restoration activities by sub‐basin according to the habitat needs of Endangered Species Act (ESA)‐listed salmonids relative to climate change in the central Columbia River basin in Washington State (USA). The objective is to employ scenario analysis to inform and improve existing instream flow restoration projects. We assess the sensitivity of late summer (July, August, and September) flows to the following scenario simulations – singly or in combination: climate change, changes in the quantity of water used for irrigation and possible changes to existing water resource policy. Flows for four sub‐basins were modeled using the Water Evaluation and Planning system (WEAP) under historical and projected conditions of 2020 and 2040 for each scenario. Results indicate that Yakima will be the most flow‐limited sub‐basin with average reductions in streamflow of 41% under climate conditions of 2020 and 56% under 2040 conditions; 1.3–2.5 times greater than those of other sub‐basins. In addition, irrigation plays a key role in the hydrology of the Yakima sub‐basin – with flow reductions ranging from 78% to 90% under severe to extreme (i.e., 20–40%) increases in agricultural water use (2.0–4.4 times the reductions in the other sub‐basins). The Yakima and Okanogan sub‐basins are the most responsive to simulations of flow‐bolstering policy change (providing salmon with first priority water allocation and at biologically relevant flows), as demonstrated by 91–100% target flows attained. The Wenatchee and Methow sub‐basins do not exhibit similar responsiveness to simulated policy changes. Considering climate change only, we conclude that flow restoration should be prioritized first in the Yakima and Wenatchee sub‐basins, and second in the Okanogan and Methow. Considering both climate change and possible policy changes, we recommend that the Yakima sub‐basin receive the highest priority for flow restoration activities to sustain critical instream habitat for ESA‐listed salmonids.     

Place prioritization for biodiversity reserve network design: a comparison of the SITES and ResNet software packages for coverage and efficiency

Abstract. The place prioritization problem in conservation biology is that of establishing a sequentially prioritized list of places on the basis of biodiversity content. Such a list can then be used to select reserve networks that are designed to be fully representative of the biodiversity of an area as efficiently as possible (for instance, with minimum area or cost). The usual goal is the representation of all chosen biodiversity surrogates up to or beyond a required target, or to the greatest available extent. The purpose of this paper is to compare the respective performances of two place prioritization software packages, SITES and ResNet, on four datasets (distributions of termite genera in Namibia, breeding bird species in the Falkland Islands/Islas Malvinas, vertebrate species in Texas and flora and fauna species that are at risk in Québec), to determine their respective merits. The two software packages implement radically different algorithms: SITES is based on a simulated annealing procedure for finding (local) optima; ResNet uses an algorithm based on rarity and complementarity. This analysis indicates that the rarity‐complementarity based algorithm of ResNet surpasses the simulated annealing approach of SITES with respect to time and completeness. SITES, however, contains other features that are useful in conservation planning. Ways in which the two packages can be used together effectively are suggested.     

Making parks make a difference: poor alignment of policy,planning and management with protected-area impact,and ways forward

Policy and practice around protected areas are poorly aligned with the basic purpose of protection, which is to make a difference. The difference made by protected areas is their impact, defined in program evaluation as the outcomes arising from protection relative to the counterfactual of no protection or a different form of protection. Although impact evaluation of programs is well established in fields such as medicine, education and development aid, it is rare in nature conservation. We show that the present weak alignment with impact of policy targets and operational objectives for protected areas involves a great risk: targets and objectives can be achieved while making little difference to the conservation of biodiversity. We also review potential ways of increasing the difference made by protected areas, finding a poor evidence base for the use of planning and management ‘levers’ to better achieve impact. We propose a dual strategy for making protected areas more effective in their basic role of saving nature, outlining ways of developing targets and objectives focused on impact while also improving the evidence for effective planning and management.