3,223 research outputs found
The Realization Doctrine in Florida Corporate Income Taxation: A History and an Analysis Since \u3cem\u3eS.R.G.\u3c/em\u3e
The authors analyze the present status of the doctrines of realization and recognition as they exist in Florida corporate income taxation. Relevant legislative history and recent cases, focusing on a conflict between these doctrines, are examined. The resulting problems are analyzed and possible solutions suggested
The Realization Doctrine in Florida Corporate Income Taxation: A History and an Analysis Since \u3cem\u3eS.R.G.\u3c/em\u3e
The authors analyze the present status of the doctrines of realization and recognition as they exist in Florida corporate income taxation. Relevant legislative history and recent cases, focusing on a conflict between these doctrines, are examined. The resulting problems are analyzed and possible solutions suggested
Evaluation of Front Detection Methods for Satellite-Derived SST Data Using In Situ Observations
Sea surface temperature (SST) fronts detected in Advanced Very High Resolution Radiometer (AVHRR) data using automated edge-detection algorithms were compared to fronts found in continuous measurements of SST made aboard a ship of opportunity. Two histograms (a single-image and a multi-image method) and one gradient algorithm were tested for the occurrence of two types of errors: (a) the detection of false fronts and (b) the failure to detect fronts observed in the in situ data. False front error rates were lower for the histogram methods (27%–28%) than for the gradient method (45%). Considering only AVHRR fronts for which the SST gradient along the ship track was greater than 0.1°C km−1, error rates drop to 14% for the histogram methods and 29% for the gradient method. Missed front error rates were lower using the gradient method (16%) than the histogram methods (30%). This error rate drops significantly for the histogram methods (5%–10%) if fronts associated with small-scale SST features (km) are omitted from the comparison. These results suggest that frontal climatologies developed from the application of automated edge-detection methods to long time series of AVHRR images provide acceptably accurate statistics on front occurrence
Private Multiplicative Weights Beyond Linear Queries
A wide variety of fundamental data analyses in machine learning, such as
linear and logistic regression, require minimizing a convex function defined by
the data. Since the data may contain sensitive information about individuals,
and these analyses can leak that sensitive information, it is important to be
able to solve convex minimization in a privacy-preserving way.
A series of recent results show how to accurately solve a single convex
minimization problem in a differentially private manner. However, the same data
is often analyzed repeatedly, and little is known about solving multiple convex
minimization problems with differential privacy. For simpler data analyses,
such as linear queries, there are remarkable differentially private algorithms
such as the private multiplicative weights mechanism (Hardt and Rothblum, FOCS
2010) that accurately answer exponentially many distinct queries. In this work,
we extend these results to the case of convex minimization and show how to give
accurate and differentially private solutions to *exponentially many* convex
minimization problems on a sensitive dataset
Stanford Aerospace Research Laboratory research overview
Over the last ten years, the Stanford Aerospace Robotics Laboratory (ARL) has developed a hardware facility in which a number of space robotics issues have been, and continue to be, addressed. This paper reviews two of the current ARL research areas: navigation and control of free flying space robots, and modelling and control of extremely flexible space structures. The ARL has designed and built several semi-autonomous free-flying robots that perform numerous tasks in a zero-gravity, drag-free, two-dimensional environment. It is envisioned that future generations of these robots will be part of a human-robot team, in which the robots will operate under the task-level commands of astronauts. To make this possible, the ARL has developed a graphical user interface (GUI) with an intuitive object-level motion-direction capability. Using this interface, the ARL has demonstrated autonomous navigation, intercept and capture of moving and spinning objects, object transport, multiple-robot cooperative manipulation, and simple assemblies from both free-flying and fixed bases. The ARL has also built a number of experimental test beds on which the modelling and control of flexible manipulators has been studied. Early ARL experiments in this arena demonstrated for the first time the capability to control the end-point position of both single-link and multi-link flexible manipulators using end-point sensing. Building on these accomplishments, the ARL has been able to control payloads with unknown dynamics at the end of a flexible manipulator, and to achieve high-performance control of a multi-link flexible manipulator
Laboratory Determination of the Infrared Band Strengths of Pyrene Frozen in Water Ice: Implications for the Composition of Interstellar Ices
Broad infrared emission features (e.g., at 3.3, 6.2, 7.7, 8.6, and 11.3
microns) from the gas phase interstellar medium have long been attributed to
polycyclic aromatic hydrocarbons (PAHs). A significant portion (10%-20%) of the
Milky Way's carbon reservoir is locked in PAH molecules, which makes their
characterization integral to our understanding of astrochemistry. In molecular
clouds and the dense envelopes and disks of young stellar objects (YSOs), PAHs
are expected to be frozen in the icy mantles of dust grains where they should
reveal themselves through infrared absorption. To facilitate the search for
frozen interstellar PAHs, laboratory experiments were conducted to determine
the positions and strengths of the bands of pyrene mixed with H2O and D2O ices.
The D2O mixtures are used to measure pyrene bands that are masked by the strong
bands of H2O, leading to the first laboratory determination of the band
strength for the CH stretching mode of pyrene in water ice near 3.25 microns.
Our infrared band strengths were normalized to experimentally determined
ultraviolet band strengths, and we find that they are generally ~50% larger
than those reported by Bouwman et al. based on theoretical strengths. These
improved band strengths were used to reexamine YSO spectra published by Boogert
et al. to estimate the contribution of frozen PAHs to absorption in the 5-8
micron spectral region, taking into account the strength of the 3.25 micron CH
stretching mode. It is found that frozen neutral PAHs contain 5%-9% of the
cosmic carbon budget, and account for 2%-9% of the unidentified absorption in
the 5-8 micron region.Comment: Accepted for publication in ApJ on 14 Feb 201
Comparative biogeochemistry of water in intertidal Onuphis (polychaeta) and Upogebia (crustacea) burrows: temporal patterns and causes
The burrows of macrobenthos represent an important class of sedimentary microenvironments which significantly influence chemical, biological, and physical characteristics of a deposit. In intertidal regions, the time-dependent changes in composition during ebb-tide of water contained in burrows is a sensitive indicator of biogenic and abiogenic chemical reactions in burrow walls and adjacent sediment. Comparison of time series water samples taken from Onuphis jenneri (polychaete) and Upogebia affinis (crustacean) burrows in the same tidal flat demonstrate substantial differences in biogeochemical microenvironments despite the spatial proximity of the two species. Both types of burrows are influenced by the same general kinds of biogeochemical reactions but the relative intensity of these reactions differs in each case. Evidence for both heterotrophic and chemoautotrophic metabolic activity in each burrow type comes from the build-up or consumption patterns in burrow water of solutes such as NH4+, NO3−, Mn++, l−, HPO4−, and HCO3−. Burrow irrigation models and the stoichiometry of solute build-up imply that Upogebia burrows are sites of more intense nitrification-denitrification and microbial activity generally than are Onuphis tubes. Upogebia burrow water is also distinctly undersaturated with respect to carbonate minerals and has high numbers of bacteria relative to Onuphis. In addition to reaction rates, burrow geometry and the adsorption-diffusive permeability properties of the burrow wall also affect transient behavior of solutes. The organic burrow lining of Onuphis shows linear adsorption isotherms for positive, negative, and neutrally charged solutes represented by NH4−, HP04−, and Si(OH)4. Diffusion-reaction modeling demonstrates that adsorption, in particular, can significantly lower the transient state concentrations of burrow water trace solutes even for tube wall thicknesses of only 200 μm. The observed differences between burrow microenvironments of the two species living in close proximity suggest distinct biogeochemical associations between microbes and species specific biogenic structures
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