Informed Consent for the Human Research Subject with a Neurologic Disorder.

The doctrine of informed consent sits at the intersection of law, ethics, and neuroscience, posing unique challenges for human subject research involving neurological patients. These challenges are compounded by the variegated nature of both neurological injury and the law governing research consent. This article provides a framework for investigators likely to encounter subjects with some degree of neurological impairment, whose capacity to consent requires scrupulous assessment prior to enrollment in research trials. We consider several researches and disease contexts-from emergency epilepsy research to long-term dementia research-and clarify the ethical and legal principles governing consent for participation in each. We additionally explore empirical research on consent capacity and survey several areas of emerging ethical import that will require the attention of investigators in decades to come

Fishes of the Mountain Province Section of the Ouachita River

A survey of the fishes of the mountain province section of the Ouachita River from the headwaters to Remmel Dam using field collections, literature records, and museum collections showed the ichthyofauna to be made up of 80 species representing 16 families. Fourteen species not previously reported from the mountain province section of the river were collected in this survey. These species include Ichthyomyzon gagei, Nocomis asper, Notropis ortenburgeri, N. rubellus, Pimephales promelas, Moxostoma carinatum, Noturus taylori, Fundulus notatus, Lepomis humilis, Etheostoma histrio, E. proeliare, Percina maculata, P. nasuta, and P. uranidea. The Nocomis specimens were the first collected from the Ouachita River system and the discovery of Noturus taylori represents a major range extension

Joint-space tracking of workspace trajectories in continuous time

We present a controller for a class of robotics manipulators which provides exponential convergence to a desired end-effector trajectory using gains specified in joint-space. This is accomplished without appeal to the use of discrete inverse-kinematics algorithms, allowing the controller to be posed entirely in continuous time

Control for an Autonomous Bicycle

The control of nonholonomic and underactuated systems with symmetry is illustrated by the problem of controlling a bicycle. We derive a controller which, using steering and rear-wheel torque, causes a model of a riderless bicycle to recover its balance from a near fall as well as converge to a time parameterized path in the ground plane. Our construction utilizes new results for both the derivation of equations of motion for nonholonomic systems with symmetry, as well as the control of underactuated robotic systems

Dynamic inversion and polar decomposition of matrices

Using the recently introduced concept of a "dynamic inverse" of a map, along with its associated analog computational paradigm. we construct continuous-time nonlinear dynamical systems which produce both regular and generalized inverses of time-varying and fixed matrices, as well as polar decompositions

Tracking implicit trajectories

Output tracking of implcitly defined reference trajectories is examined. A continuous-time nonlinear dynamical system is constructed that produces explicit estimates of time-varying implicit trajectories. We prove that incorporation of this "dynamic inverter" into a tracking controller provides exponential output tracking of the implicitly defined trajectory for nonlinear control systems having vector relative degree and well-behaved internal dynanmics

A dynamic inverse for nonlinear maps

We consider the problem of estimating the time-varying root of a time-dependent nonlinear map. We introduce a "dynamic inverse" of a map, another generally time-dependent map which one composes with the original map to form a nonlinear vector-field. The flow of this vector field decays exponentially to the root. We then show how a dynamic inverse may be determined dynamically while being used simultaneously to find a root. We construct a continuous-time analog computational paradigm around the dynamic inverse