ABSTRACT
Flux flow was studied over an entire temperature range down to T approximately 2% of T(c) by using intense pulsed current densities to overcome flux-vortex pinning. The resistivity at high vortex velocities is proportional to B and roughly follows rho approximately rho(n)B/H(c2), with a prefactor of order unity. Contrary to some speculation, rho(n) saturates to a finite residual value as T-->0, indicating a metallic (rho-->finite) rather than insulating (rho-->infinity) normal state, and the vortex dissipation continues to be conventional as T-->0.
ABSTRACT
A central objective of the LOIS Community Research Programme was to provide estimates of the land-ocean flux of chemical species from the LOIS study area. In the absence of detailed information on the concentration of most of the dissolved and particulate-associated chemical constituents, it has proved necessary to make use of the relatively infrequent samples collected in the UK Harmonised Monitoring Scheme, in order to estimate chemical fluxes for the LOIS rivers. In these circumstances, standard procedures may provide unreliable results, and a new approach has been developed to derive improved estimates of chemical flux from the LOIS study area. This approach is based on the generation of detailed synthetic time series of concentration, which are used to estimate the likely errors associated with different flux calculation procedures, especially those resulting from differences in the timing of chemographs and hydrographs during storm events. The approach was applied on a river by river and determinand by determinand basis to identify and to employ the best methods for computing fluxes of 45 chemical determinands from the LOIS study area during the period 1992-1996.
ABSTRACT
The purpose of this experiment was to explore the possibility that the inconsistent findings of Brehmer and Hagafors (1986, Organizational Behavior and Human Decision Processes, 38, 181-195), Sniezek and Buckley (1995, Organizational Behavior and Human Decision Processes, 62, 159-174), and leader-member exchange research regarding leaders' propensity to differentially and accurately weight staff input can be explained as a result of experience, the availability to the leader of staff member judgment confidence, and the cumulative past accuracy of each staff member. The availability to the team leader of staff member past judgment accuracy and staff member judgment confidence was provided in an environment in which differential staff weighting was the appropriate staff utilization strategy. Eighty-four leaders of four-person decision-making teams performed 63 decisions on a computerized decision-making task. Both experience and providing leaders with cumulative staff past accuracy information were related to greater staff weighting variability and greater staff weighting accuracy. Although positively related to staff weighting, staff confidence information did not improve leader weighting variability nor actual staff weighting accuracy. Copyright 1999 Academic Press.
ABSTRACT
The akinesia resulting from Parkinson's disease or striatal dopamine depletion in experimental animals can be ameliorated or reversed by inactivation of the subthalamic nucleus. This inactivation might be effective by restoring balance to the basal ganglia motor circuits. Alternatively, new movement-related deficits might be introduced which mask the original impairments (e.g. hyperkinesia might replace hypokinesia). In the present study, striatal dopamine depletion was effected unilaterally, in order to dissociate generalized effects, e. g. hyperkinesia, from response-specific initiation effects. Rats were trained in a lateralized visual reaction time task and then assigned to one of four groups: striatal dopamine depletion; cell body lesion of the subthalamic nucleus; combined striatal dopamine depletion and subthalamic nucleus lesion; or control. As expected, rats with striatal dopamine depletion exhibited slower reaction time and a bias to respond to the ipsilateral side. The subthalamic nucleus lesion resulted in no reaction time change (in particular, there was no evidence of faster reaction times), but there was an increase in anticipatory responding. The group with the combined striatal dopamine depletion and subthalamic nucleus lesion had no reaction time impairment. This group showed an increase in anticipatory errors and a contralateral response bias. These data demonstrate that lesions of the subthalamic nucleus do not merely cancel the akinesia which follows striatal dopamine depletion by the addition of a hyperkinetic impairment. Rather, there appears to be a change in the balance of the motor system.
ABSTRACT
Eulogy given at the Lutheran Church of the Atonement, Wyomissing, Pennsylvania on March 13, 1996
