Linear, High Dynamic Range Isolated Skin Resistance Transducer Circuit for Neurophysiological Research in Individuals after Spinal Cord Injury

The quantification of skin resistance in individuals after spinal cord injury for the purpose of neurophysiological research is difficult, mainly as a consequence of decreased activity of sweat glands in the injured human organism. In this original work, we propose a custom electrical skin resistance transducer, featuring extremely low patient auxiliary current, linear response and high dynamic range. After the design and fabrication of the prototype device, we conducted preliminary benchmark tests. We found that our prototype transducer was able to linearly report a broad range of resistance presented to its input terminals, which is not usually found in skin resistance research instrumentation. The basic design idea is viable and, following further research, an improved version of presented prototype device may be used for the purpose of neurophysiological research in individuals after spinal cord injury

Expanding the scope of metal-free enantioselective allylic substitutions: Anthrones

The highly enantioselective asymmetric allylic alkylation of Morita–Baylis–Hillman carbonates with anthrones is presented. The reaction is simply catalyzed by cinchona alkaloid derivatives affording the final alkylated products in good yields and excellent enantioselectivities

Linear, High Dynamic Range Isolated Skin Resistance Transducer Circuit for Neurophysiological Research in Individuals after Spinal Cord Injury

The quantification of skin resistance in individuals after spinal cord injury for the purpose of neurophysiological research is difficult, mainly as a consequence of decreased activity of sweat glands in the injured human organism. In this original work, we propose a custom electrical skin resistance transducer, featuring extremely low patient auxiliary current, linear response and high dynamic range. After the design and fabrication of the prototype device, we conducted preliminary benchmark tests. We found that our prototype transducer was able to linearly report a broad range of resistance presented to its input terminals, which is not usually found in skin resistance research instrumentation. The basic design idea is viable and, following further research, an improved version of presented prototype device may be used for the purpose of neurophysiological research in individuals after spinal cord injury

Online Algorithms for Multi-Level Aggregation

International audienceIn the Multi-Level Aggregation Problem (MLAP), requests arrive atthe nodes of an edge-weighted tree T, and have to be served eventually. A service is defined as a subtree X of T that contains its root. This subtree X serves allrequests that are pending in the nodes of X, and the cost of this service isequal to the total weight of X. Each request also incurs waiting costbetween its arrival and service times. The objective is to minimize the totalwaiting cost of all requests plus the total cost of all service subtrees.MLAP is a generalization of some well-studied optimization problems; forexample, for trees of depth 1, MLAP is equivalent to the TCPAcknowledgment Problem, while for trees of depth 2, it is equivalent to theJoint Replenishment Problem. Aggregation problem for trees of arbitrary deptharise in multicasting, sensor networks, communication in organizationhierarchies, and in supply-chain management. The instances of MLAPassociated with these applications are naturally online, in the sense thataggregation decisions need to be made without information about futurerequests.Constant-competitive online algorithms are known for MLAP with one or twolevels. However, it has been open whether there exist constant competitiveonline algorithms for trees of depth more than 2. Addressing this openproblem, we give the first constant competitive online algorithm for networksof arbitrary (fixed) number of levels. The competitive ratio is $O(D^42^D)$,where D is the depth of T. The algorithm works for arbitrary waitingcost functions, including the variant with deadlines.We include several additional results in the paper. We show that a standardlower-bound technique for MLAP, based on so-called Single-Phaseinstances, cannot give super-constant lower bounds (as a function of the treedepth). This result is established by giving an online algorithm with optimalcompetitive ratio 4 for such instances on arbitrary trees. We also study the MLAP variant when the tree is a path, for which we givea lower bound of 4 on the competitive ratio, improving the lower bound known for general MLAP. We complement this with a matching upper bound for the deadline setting