The Impact of Students\u27 Perceived Computer Experience on Behavior and Performance in an Introductory Information Systems Course

In this study the impact of perceived computer experience on the behavior and performance of students in an introductory information systems (IS) course with both lab and lecture components was examined. Perceived computer experience was predicted to affect behavior and performance in the course because of its relationship to positive internal attitudes towards computers and because students\u27 perceptions of their computer experience are related to their actual level of knowledge about computers. The results of the study showed that higher levels of perceived computer experience positively affected lecture and lab homework and exam performance. In addition, higher levels of positive class behaviors (attendance and extra-credit participation) positively affected both lecture and lab exam performance. Gender and lab/lecture section were included as control variables and both had an impact on behavior and performance. Women participated more in extra-credit opportunities. Lecture and lab sections varied significantly with regard to attendance, extra-credit participation, lab homework, and lab and lecture exam performance. These results are discussed in the context of previous research on factors affecting introductory information systems course performance and prior research on the effects of prior computer experience on learning

Dispatcher: A Theory-Based Design for Study of Real-Time Decision-Making

Dispatcher is a computer simulation being used in a series of experiments involving the study of real-time dynamic decision making. The design of the simulation is based on current theory of providing decision support for this type of decision making task. This paper provides an overview of the process used in designing and implementing Dispatcher, as well as a description of some of the main features of the simulation as they relate to current research efforts in the study of decision support for RTDDM

PERFORMANCE =/= BEHAVIOR: A STUDY IN THE FRAGILITY OF EXPERTISE

The fragility of expertise is a known, but little understood, feature of expert reasoning. Essentially, fragili(y refers to the performance degradation of experts as task properties change. A study is presented in which the fragility of expertise in a complex, real-world task -- reactive scheduling -- is investigated. Six novices (students, trained in the task but with no experience in the domain) and three expert schedulers (ranging from six to 20 years of experience in the domain) each completed six reactive scheduling tasks varying in difficulty. All subjects were run individually and their protocols (verbal and action) were recorded on video-tape. Simple modifications to the task environment were sufficient to degrade the pelfonnance of the experts, sometimes to the level of the novices. However, an analysis of the behavior of the subjects suggests that a problem space characterization of fragility can explain how that degradation occurred. The behavior captured in the video-tapes (both verbal utterances and physical actions) show that, in this task, the primary source of degradation was the inappropriate formation of problem space components. That is, experts were stuck in the wrong problem space. Specifically, the experts would use inadequate search control knowledge while traversing problem spaces and/or repeatedly attempt to implement operators or types of search control knowledge that were not allowed in the experimental task, but were quite valid in the real task setting. We conclude by discussing the concept of expert fragility and how it should be taken into account when designing systems based on the construct of expertise: expert systems

Characterization of Lipid Bioenergetic Markers in Alzheimer's Disease (AD) in Apolipoprotein E4 (<i>APOE</i>) and non-E4 Carriers.

Alzheimer’s disease (AD) is a progressive neurodegenerative disease of ageing with an estimated prevalence of 36 million worldwide. Individuals carrying one ε4 allele of the apolipoprotein E gene (APOE) are 6 times more likely to develop AD than ε3 homozygotes. Further, ε4 carriers have an abnormal increased reliance on fatty acid oxidation (FAO). The L-carnitine system consisting of L-carnitine and its esters (acylcarnitines) plays an important role in FAO. We therefore hypothesized that changes in blood and brain levels of L-carnitine, its metabolites (TMAO and GBB) as well as acylcarnitines would be indicative of dysfunctional FAO in ageing ε4 carriers influencing AD onset and progression. The L-carnitine system was evaluated in blood and brain in association with APOE in multiple cohorts of controls and patients over the continuum of AD. To investigate the influence of age and APOE on this system a mouse model of AD with human APOE was examined. In this model ex vivo cerebrovascular uptake of L-carnitine metabolites and fatty acids (FAs) were also investigated in relation to APOE. Additionally, a 1-week L-carnitine oral challenge was performed to evaluate the influence of APOE on L-carnitine metabolism. These data suggested that the L-carnitine pathway is dysregulated early on in AD, particularly among ε4 carriers. In the brain, changes in the L-carnitine system were related to AD pathology in an APOE-dependent manner. In mouse models APOE did not affect cerebrovascular uptake of L-carnitine metabolites and FAs or the metabolism of L-carnitine after oral challenge. However, acylcarnitines were differentially affected in different genotypes after cerebrovascular uptake of compounds and L-carnitine challenge suggesting altered in FAO flux in different APOE genotypes. Understanding disturbances in the L-carnitine system with age, in relation to APOE genotypes, and their collective contributions to AD will help develop targeted prevention and therapeutic strategies

Linkage between lateral circulation and near-surface vertical mixing in a coastal plain estuary

Microstructure and current velocity measurements were collected at a cross-channel transect in the James River under spring and neap tidal conditions in May 2010 to study cross-estuary variations in vertical mixing. Results showed that near-surface mixing was related to lateral circulation during the ebb phase of a tidal cycle, and that the linkage was somewhat similar from neap to spring tides. During neap tides, near-surface mixing was generated by the straining of lateral density gradients influenced by the advection of fresh, riverine water on the right side (looking seaward) of the transect. Spring tide results revealed similar findings on the right side of the cross section. However, on the left side, the straining by velocity shears acted in concert with density straining. Weak along-estuary velocities over the left shoal were connected to faster velocities in the channel via a clockwise lateral circulation (looking seaward). These results provided evidence that in the absence of direct wind forcing, near-surface vertical mixing can occur from mechanisms uncoupled from bottom friction

Tunable Oscillations in the Purkinje Neuron

In this paper, we study the dynamics of slow oscillations in Purkinje neurons in vitro, and derive a strong association with a forced parametric oscillator model. We demonstrate the precise rhythmicity of the oscillations in Purkinje neurons, as well as a dynamic tunability of this oscillation using a photo-switchable compound. We show that this slow oscillation can be induced in every Purkinje neuron, having periods ranging between 10-25 seconds. Starting from a Hodgkin-Huxley model, we also demonstrate that this oscillation can be externally modulated, and that the neurons will return to their intrinsic firing frequency after the forced oscillation is concluded. These results signify an additional functional role of tunable oscillations within the cerebellum, as well as a dynamic control of a time scale in the brain in the range of seconds.Comment: 12 pages, 5 figure

The role of inhibitory feedback for information processing in thalamocortical circuits

The information transfer in the thalamus is blocked dynamically during sleep, in conjunction with the occurence of spindle waves. As the theoretical understanding of the mechanism remains incomplete, we analyze two modeling approaches for a recent experiment by Le Masson {\sl et al}. on the thalamocortical loop. In a first step, we use a conductance-based neuron model to reproduce the experiment computationally. In a second step, we model the same system by using an extended Hindmarsh-Rose model, and compare the results with the conductance-based model. In the framework of both models, we investigate the influence of inhibitory feedback on the information transfer in a typical thalamocortical oscillator. We find that our extended Hindmarsh-Rose neuron model, which is computationally less costly and thus siutable for large-scale simulations, reproduces the experiment better than the conductance-based model. Further, in agreement with the experiment of Le Masson {\sl et al}., inhibitory feedback leads to stable self-sustained oscillations which mask the incoming input, and thereby reduce the information transfer significantly.Comment: 16 pages, 15eps figures included. To appear in Physical Review

Stable Propagation of a Burst Through a One-Dimensional Homogeneous Excitatory Chain Model of Songbird Nucleus HVC

We demonstrate numerically that a brief burst consisting of two to six spikes can propagate in a stable manner through a one-dimensional homogeneous feedforward chain of non-bursting neurons with excitatory synaptic connections. Our results are obtained for two kinds of neuronal models, leaky integrate-and-fire (LIF) neurons and Hodgkin-Huxley (HH) neurons with five conductances. Over a range of parameters such as the maximum synaptic conductance, both kinds of chains are found to have multiple attractors of propagating bursts, with each attractor being distinguished by the number of spikes and total duration of the propagating burst. These results make plausible the hypothesis that sparse precisely-timed sequential bursts observed in projection neurons of nucleus HVC of a singing zebra finch are intrinsic and causally related.Comment: 13 pages, 6 figure