A review of the accounting treatment for contingencies arising from environmental issues

The purpose of this project is to review the U.S. GAAP treatment of issues arising from environmental contingencies. This review consists of accounting literature and pronouncements issued by the FASB and SEC as well as environmental legislation, most notably CERCLA. The results of this review showed that the accounting industry has been one step behind environmental legislation and continues in its endeavor to provide financial statement users with useful information

Dynamic updating of distributed neural representations using forward models

In this paper, we present a continuous attractor network model that we hypothesize will give some suggestion of the mechanisms underlying several neural processes such as velocity tuning to visual stimulus, sensory discrimination, sensorimotor transformations, motor control, motor imagery, and imitation. All of these processes share the fundamental characteristic of having to deal with the dynamic integration of motor and sensory variables in order to achieve accurate sensory prediction and/or discrimination. Such principles have already been described in the literature by other high-level modeling studies (Decety and Sommerville in Trends Cogn Sci 7:527-533, 2003; Oztop etal. in Neural Netw 19(3):254-271, 2006; Wolpert etal. in Philos Trans R Soc 358:593-602, 2003). With respect to these studies, our work is more concerned with biologically plausible neural dynamics at a population level. Indeed, we show that a relatively simple extension of the classical neural field models can endow these networks with additional dynamic properties for updating their internal representation using external commands. Moreover, an analysis of the interactions between our model and external inputs also shows interesting properties, which we argue are relevant for a better understanding of the neural processes of the brai

Emergent properties of electrically coupled smooth muscle cells

Asynchronous and synchronous calcium oscillations occur in a variety of cells. A well-established pathway for intercellular communication is provided by gap junctions which connect adjacent cells and can mediate electrical and chemical coupling. Several experimental studies report that cells presenting only a transient increase when freshly dispersed may oscillate when they are coupled. Such observations suggest that the role of gap junctions is not only to coordinate calcium oscillations of adjacent cells. Gap junctions may also be important to generate oscillations. Here we illustrate the emergent properties of electrically coupled smooth muscle cells using a model that we recently proposed. A bifurcation analysis in the case of two cells reveals that synchronous and asynchronous calcium oscillations can be induced by electrical coupling. In a larger population of smooth muscle cells, electrical coupling may result in the creation of groups of cells presenting synchronous calcium oscillations. The elements of one group may be distant from each other. Moreover, our results highlight a general mechanism by which gap junctional electrical coupling can give rise to out of phase calcium oscillations in smooth muscle cells that are non-oscillating when uncoupled. All these observations remain true in the case of non-identical cells, except that the solution corresponding to synchronous calcium oscillations disappears and that the formation of groups is sensitive to the degree of heterogeneit

Coevolution of active vision and feature selection

Abstract.: We show that complex visual tasks, such as position- and size-invariant shape recognition and navigation in the environment, can be tackled with simple architectures generated by a coevolutionary process of active vision and feature selection. Behavioral machines equipped with primitive vision systems and direct pathways between visual and motor neurons are evolved while they freely interact with their environments. We describe the application of this methodology in three sets of experiments, namely, shape discrimination, car driving, and robot navigation. We show that these systems develop sensitivity to a number of oriented, retinotopic, visual-feature-oriented edges, corners, height, and a behavioral repertoire to locate, bring, and keep these features in sensitive regions of the vision system, resembling strategies observed in simple insect

Optimization of System Maturity and Equivalent System Mass for Exploration Systems Development Planning

The Exploration Systems Mission Directorate of the National Aeronautics and Space Administration (NASA) is currently pursuing the development of the next generation of human spacecraft and exploration systems throughout the Constellation Program. This includes, among others, habitation technologies for supporting lunar and Mars exploration. The key to these systems is the Exploration Life Support (ELS) system that composes several technology development projects related to atmosphere revitalization, water recovery, waste management and habitation. The proper functioning of these technologies is meant to produce sufficient and balanced resources of water, air, and food to maintain a safe and comfortable environment for long-term human habitation and exploration of space

M-Theory on S^1/Z_2 : New Facts from a Careful Analysis

We carefully re-examine the issues of solving the modified Bianchi identity, anomaly cancellations and flux quantization in the S^1/Z_2 orbifold of M-theory using the boundary-free "upstairs" formalism, avoiding several misconceptions present in earlier literature. While the solution for the four-form G to the modified Bianchi identity appears to depend on an arbitrary parameter b, we show that requiring G to be globally well-defined, i.e. invariant under small and large gauge and local Lorentz transformations, fixes b=1. This value also is necessary for a consistent reduction to the heterotic string in the small-radius limit. Insisting on properly defining all fields on the circle, we find that there is a previously unnoticed additional contribution to the anomaly inflow from the eleven-dimensional topological term. Anomaly cancellation then requires a quadratic relation between b and the combination lambda^6/kappa^4 of the gauge and gravitational coupling constants lambda and kappa. This contrasts with previous beliefs that anomaly cancellation would give a cubic equation for b. We observe that our solution for G automatically satisfies integer or half-integer flux quantization for the appropriate cycles. We explicitly write out the anomaly cancelling terms of the heterotic string as inherited from the M-theory approach. They differ from the usual ones by the addition of a well-defined local counterterm. We also show how five-branes enter our analysis.Comment: 32 pages, version to appear in Nucl. Phys. B, no figures, uses PHYZZ

Multi-hydrogenated compounds monitoring in optical fibre manufacturing process by photoacoustic spectroscopy

Sub-ppm hydrogen chloride (HCl) and water vapour (H2O) monitoring using photoacoustic spectroscopy in optical fibre manufacturing is reported. The development and performance of a sensor based on an acoustic resonant configuration is described, and on-site measurements are presented. Two DFB lasers emitting in the 1370nm and 1740nm range were used for the detection of H2O and HCl, respectively. A detection limit (defined for a SNR=3) of 60ppb for HCl and 40ppb for H2O was achieved. Contamination sources of the carrier gas used for the fibre preform manufacturing are identified and discusse

An investigation of the effects of fabric and stencil on resolution and registration in the screen printed circuit board

Printed circuit boards are a major component of most modern electronic devices. There are currently two major processes by which circuit boards are imaged; dry film and screen printing. This study investigated the screen printed circuit board. The resolution and registration limits are primary concerns of the screen circuit printer. These two factors are greatly influenced by two screen components; fabric and stencil system. The effects that two fabrics and two stencil systems had on the resolution and registration capabilities of a screen circuit printing system were determined. A test target was printed on a circuit substrate by a screen printing press under production conditions. Data on registration variation and line resolution was collected and analyzed statistically to determine if fabric, stencil or an interaction of both had a significant effect. A strong interaction effect of fabric and stencil upon resolution was found to occur when stainless steel mesh was used with the two stencil systems. Stainless steel combined with indirect stencil yielded the best resolution, while steel with capillary direct stencil yielded the worst resolution. A combination of polyester monofilament fabric and either indirect or capillary direct stencil yielded resolution between the two values found with the steel fabric. Registration variability was found to be significantly affected by the factor FABRIC. Steel mesh produced less registration variability than polyester mesh. However, this registration variability of fabrics seems to be significantly related to the condition of the fabric – new or used. Conclusions of the study were that for best resolution and least registration variability, stainless steel fabric combined with indirect stencils should be used. The second choice would be dyed monofilament polyester combined with either indirect or capillary direct stencil systems. The combination of stainless steel and capillary direct stencil should be avoided. It should be noted that run length is a major consideration when choosing fabric/stencil combinations for circuit imaging. Further investigations of registration variability in stainless steel and polyester monofilament fabrics over numerous runs would also yield valuable information for the screen circuit printer