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Critical Inputs (critical + input)
Selected AbstractsNeural plasticity and human development: the role of early experience in sculpting memory systemsDEVELOPMENTAL SCIENCE, Issue 2 2000Charles A. Nelson The concept of sensitive or critical periods in the context of memory development is examined in this paper. I begin by providing examples of the role of experience in influencing sensory, linguistic and emotional functioning. This is followed by a discussion of the role of experience in influencing cognitive functioning, particularly memory. Based on this discussion, speculation is offered that the infant's proclivity for novelty, which makes its appearance shortly after birth, provides critical input into a nervous system that will eventually be set up to learn and remember for the entire lifespan. Because learning and memory are fundamental to the survival of our species, those aspects of the nervous system that permit the encoding and retention of new information are remarkably malleable from the outset, even in the face of some types of neural trauma. This flexibility is retained for many years so long as the learning and memory ,system' is challenged. The implications of this model are discussed in the context of those life events that might undermine the longevity of memory systems. [source] Incentives for Managing Accounting Information: Property-Liability Insurer Stock-Charter ConversionsJOURNAL OF RISK AND INSURANCE, Issue 2 2004David Mayers Incentives to manage accounting information are examined within 63 property-liability insurance company conversions from mutual ownership to common stock charter. In the conversion process, policyholders' embedded equity claims must be valued. Since mutuals have no separately traded equity, accounting numbers are a critical input in this valuation. Incentives for surplus management vary across firms; the strongest evidence of surplus management is observed among firms where the mutual's executives become the firm's principal stockholders following conversion. The evidence suggests that converting firms manage accounting information primarily by adjusting liabilities and selectively establishing investment losses,not by altering claims settlement policy. [source] The Empire Meets the New Deal: Interwar Encounters in Conservation and Regional PlanningGEOGRAPHICAL RESEARCH, Issue 4 2005J.M. POWELL Abstract British imperial and American experiences in conservation and planning are providing fresh interdisciplinary challenges for university teaching and research. The Roosevelt administration's ,New Deal' included government-sponsored interventions in soil erosion and water management and sophisticated regional development agendas. Reviewing samples of the latter areas of concern, this article explores the proposition that, although the British Empire was scarcely bereft of comparable interwar programmes and was becoming somewhat preoccupied with centrifugal tendencies, persistent porosity, exhausting struggles with postwar reconstruction, and comprehensive economic depression, New Deal evangelism was in fact variously anticipated, harnessed, challenged and ignored. A discussion of widely separated national and regional examples locates a layered interplay between uneven imperial and US pulsations, independent local manoeuvres, and critical inputs from key individual agents. The most important filters included the presence of comparatively robust bureaucratic infrastructures and the cultivation of international relationships by scientists and technologists. Encounters with convergent revisionism suggest cautionary leads for students, researchers and teachers alike. Reconstructions of selected contexts underline the presence of familiar posturing, opportunism, and astute patriotic deployment during the emergence of modern styles of globalization. [source] Identification of application-specific critical inputs for the 1991 Johnson and Ettinger vapor intrusion algorithmGROUND WATER MONITORING & REMEDIATION, Issue 1 2005Paul C. Johnson At sites where soil or ground water contains chemicals of concern, there is the potential for chemical vapors to migrate through the subsurface to nearby basements, buildings, and other enclosed spaces. The 1991 Johnson and Ettinger algorithm and subsequent refinements are often used to assess the significance of this pathway and to establish target cleanup levels. To facilitate its use, the U.S. EPA distributes spreadsheets programmed with the 1991 Johnson and Ettinger algorithm. These user-friendly spreadsheets make the equations more accessible; however, the U.S. EPA spreadsheets require a large number of inputs (>20), and as a result, relationships between model inputs and outputs are not well understood and users are not able to identify and focus on the critical inputs. The U.S. EPA spreadsheets also allow users to inadvertently enter inconsistent and unreasonable sets of input values, and these often lead to unreasonable outputs. The objective of this work, therefore, is to help users develop a better understanding of the relationships between inputs and outputs so that they can identify critical inputs and also to ensure reasonableness of inputs and outputs. The 1991 Johnson and Ettinger algorithm is introduced, and differences between it and its U.S. EPA spreadsheet implementation are identified. Next, results from a parametric analysis of the algorithm are used to create a flowchart-based approach for identifying the application-specific critical inputs. Use of the flowchart-based approach is then illustrated and validated through comparison with the results of a more traditional sensitivity analysis for four scenarios. Recommendations are also given for the reformulation of inputs to minimize misapplication of the algorithm and the spreadsheets, and reasonable ranges for reformulated input values are discussed. [source] Simulating daily soil water under foothills fescue grazing with the soil and water assessment tool model (Alberta, Canada)HYDROLOGICAL PROCESSES, Issue 15 2004Emmanuel Mapfumo Abstract Grazing is common in the foothills fescue grasslands and may influence the seasonal soil-water patterns, which in turn determine range productivity. Hydrological modelling using the soil and water assessment tool (SWAT) is becoming widely adopted throughout North America especially for simulation of stream flow and runoff in small and large basins. Although applications of the SWAT model have been wide, little attention has been paid to the model's ability to simulate soil-water patterns in small watersheds. Thus a daily profile of soil water was simulated with SWAT using data collected from the Stavely Range Sub-station in the foothills of south-western Alberta, Canada. Three small watersheds were established using a combination of natural and artificial barriers in 1996,97. The watersheds were subjected to no grazing (control), heavy grazing (2·4 animal unit months (AUM) per hectare) or very heavy grazing (4·8 AUM ha,1). Soil-water measurements were conducted at four slope positions within each watershed (upper, middle, lower and 5 m close to the collector drain), every 2 weeks annually from 1998 to 2000 using a downhole CPN 503 neutron moisture meter. Calibration of the model was conducted using 1998 soil-water data and resulted in Nash,Sutcliffe coefficient (EF or R2) and regression coefficient of determination (r2) values of 0·77 and 0·85, respectively. Model graphical and statistical evaluation was conducted using the soil-water data collected in 1999 and 2000. During the evaluation period, soil water was simulated reasonably with an overall EF of 0·70, r2 of 0·72 and a root mean square error (RMSE) of 18·01. The model had a general tendency to overpredict soil water under relatively dry soil conditions, but to underpredict soil water under wet conditions. Sensitivity analysis indicated that absolute relative sensitivity indices of input parameters in soil-water simulation were in the following order; available water capacity > bulk density > runoff curve number > fraction of field capacity (FFCB) > saturated hydraulic conductivity. Thus these data were critical inputs to ensure reasonable simulation of soil-water patterns. Overall, the model performed satisfactorily in simulating soil-water patterns in all three watersheds with a daily time-step and indicates a great potential for monitoring soil-water resources in small watersheds. Copyright © 2004 John Wiley & Sons, Ltd. [source] An integrated approach to optimization of Escherichia coli fermentations using historical dataBIOTECHNOLOGY & BIOENGINEERING, Issue 3 2003Matthew C. Coleman Abstract Using a fermentation database for Escherichia coli producing green fluorescent protein (GFP), we have implemented a novel three-step optimization method to identify the process input variables most important in modeling the fermentation, as well as the values of those critical input variables that result in an increase in the desired output. In the first step of this algorithm, we use either decision-tree analysis (DTA) or information theoretic subset selection (ITSS) as a database mining technique to identify which process input variables best classify each of the process outputs (maximum cell concentration, maximum product concentration, and productivity) monitored in the experimental fermentations. The second step of the optimization method is to train an artificial neural network (ANN) model of the process input,output data, using the critical inputs identified in the first step. Finally, a hybrid genetic algorithm (hybrid GA), which includes both gradient and stochastic search methods, is used to identify the maximum output modeled by the ANN and the values of the input conditions that result in that maximum. The results of the database mining techniques are compared, both in terms of the inputs selected and the subsequent ANN performance. For the E. coli process used in this study, we identified 6 inputs from the original 13 that resulted in an ANN that best modeled the GFP fluorescence outputs of an independent test set. Values of the six inputs that resulted in a modeled maximum fluorescence were identified by applying a hybrid GA to the ANN model developed. When these conditions were tested in laboratory fermentors, an actual maximum fluorescence of 2.16E6 AU was obtained. The previous high value of fluorescence that was observed was 1.51E6 AU. Thus, this input condition set that was suggested by implementing the proposed optimization scheme on the available historical database increased the maximum fluorescence by 55%. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 274,285, 2003. [source] | ||||||||||