8,258 research outputs found
Inflation and the Taxation of Capital Income in the Corporate Sector
This detailed examination of the effect of inflation on the taxation of capital used by nonfinancial corporations considers not only the tax paid by the corporations them- selves but also the tax paid by the individuals and institutions that provide capital to the corporate sector. Although corporations deduct nominal interest payments that exceed real interest, the additional taxes that lenders pay slightly exceed the tax saving by corporate borrowers. Our calculations indicate that inflation raised the 1977 tax burden on corporate sector capital income by more than $32 billion, a 50 percent increase in the total tax burden.
Probabilistic structural mechanics research for parallel processing computers
Aerospace structures and spacecraft are a complex assemblage of structural components that are subjected to a variety of complex, cyclic, and transient loading conditions. Significant modeling uncertainties are present in these structures, in addition to the inherent randomness of material properties and loads. To properly account for these uncertainties in evaluating and assessing the reliability of these components and structures, probabilistic structural mechanics (PSM) procedures must be used. Much research has focused on basic theory development and the development of approximate analytic solution methods in random vibrations and structural reliability. Practical application of PSM methods was hampered by their computationally intense nature. Solution of PSM problems requires repeated analyses of structures that are often large, and exhibit nonlinear and/or dynamic response behavior. These methods are all inherently parallel and ideally suited to implementation on parallel processing computers. New hardware architectures and innovative control software and solution methodologies are needed to make solution of large scale PSM problems practical
The Mechanics of Embodiment: A Dialogue on Embodiment and Computational Modeling
Embodied theories are increasingly challenging traditional views of cognition by arguing that conceptual representations that constitute our knowledge are grounded in sensory and motor experiences, and processed at this sensorimotor level, rather than being represented and processed abstractly in an amodal conceptual system. Given the established empirical foundation, and the relatively underspecified theories to date, many researchers are extremely interested in embodied cognition but are clamouring for more mechanistic implementations. What is needed at this stage is a push toward explicit computational models that implement sensory-motor grounding as intrinsic to cognitive processes. In this article, six authors from varying backgrounds and approaches address issues concerning the construction of embodied computational models, and illustrate what they view as the critical current and next steps toward mechanistic theories of embodiment. The first part has the form of a dialogue between two fictional characters: Ernest, the �experimenter�, and Mary, the �computational modeller�. The dialogue consists of an interactive sequence of questions, requests for clarification, challenges, and (tentative) answers, and touches the most important aspects of grounded theories that should inform computational modeling and, conversely, the impact that computational modeling could have on embodied theories. The second part of the article discusses the most important open challenges for embodied computational modelling
Evolution of Fermion Pairing from Three to Two Dimensions
We follow the evolution of fermion pairing in the dimensional crossover from
3D to 2D as a strongly interacting Fermi gas of Li atoms becomes confined
to a stack of two-dimensional layers formed by a one-dimensional optical
lattice. Decreasing the dimensionality leads to the opening of a gap in
radio-frequency spectra, even on the BCS-side of a Feshbach resonance. The
measured binding energy of fermion pairs closely follows the theoretical
two-body binding energy and, in the 2D limit, the zero-temperature mean-field
BEC-BCS theory.Comment: 5 pages, 4 figure
Motion of a Solitonic Vortex in the BEC-BCS Crossover
We observe a long-lived solitary wave in a superfluid Fermi gas of Li
atoms after phase-imprinting. Tomographic imaging reveals the excitation to be
a solitonic vortex, oriented transverse to the long axis of the cigar-shaped
atom cloud. The precessional motion of the vortex is directly observed, and its
period is measured as a function of the chemical potential in the BEC-BCS
crossover. The long period and the correspondingly large ratio of the inertial
to the bare mass of the vortex are in good agreement with estimates based on
superfluid hydrodynamics that we derive here using the known equation of state
in the BEC-BCS crossover
Semantic role labeling for protein transport predicates
<p>Abstract</p> <p>Background</p> <p>Automatic semantic role labeling (SRL) is a natural language processing (NLP) technique that maps sentences to semantic representations. This technique has been widely studied in the recent years, but mostly with data in newswire domains. Here, we report on a SRL model for identifying the semantic roles of biomedical predicates describing protein transport in GeneRIFs – manually curated sentences focusing on gene functions. To avoid the computational cost of syntactic parsing, and because the boundaries of our protein transport roles often did not match up with syntactic phrase boundaries, we approached this problem with a word-chunking paradigm and trained support vector machine classifiers to classify words as being at the beginning, inside or outside of a protein transport role.</p> <p>Results</p> <p>We collected a set of 837 GeneRIFs describing movements of proteins between cellular components, whose predicates were annotated for the semantic roles AGENT, PATIENT, ORIGIN and DESTINATION. We trained these models with the features of previous word-chunking models, features adapted from phrase-chunking models, and features derived from an analysis of our data. Our models were able to label protein transport semantic roles with 87.6% precision and 79.0% recall when using manually annotated protein boundaries, and 87.0% precision and 74.5% recall when using automatically identified ones.</p> <p>Conclusion</p> <p>We successfully adapted the word-chunking classification paradigm to semantic role labeling, applying it to a new domain with predicates completely absent from any previous studies. By combining the traditional word and phrasal role labeling features with biomedical features like protein boundaries and MEDPOST part of speech tags, we were able to address the challenges posed by the new domain data and subsequently build robust models that achieved F-measures as high as 83.1. This system for extracting protein transport information from GeneRIFs performs well even with proteins identified automatically, and is therefore more robust than the rule-based methods previously used to extract protein transport roles.</p
Stress-life interrelationships associated with alkaline fuel cells
A review is presented concerning the interrelationships between applied stress and the expected service life of alkaline fuel cells. Only the physical, chemical, and electrochemical phenomena that take place within the fuel cell stack portion of an overall fuel cell system will be discussed. A brief review will be given covering the significant improvements in performance and life over the past two decades as well as summarizing the more recent advances in understanding which can be used to predict the performance and life characteristics of fuel cell systems that have yet to be built
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