Hocus Pocus: The Magic Within Trade Secret Law

This Note will discuss why trade secret law is the most appropriate form of IP protection for magicians seeking to protect their secrets. First it will discuss the background information on IP protections offered to magicians, specifically within copyright, patent, and trade secret law. After examining previous cases in which magicians have sought protection for their work using each of these different types of IP laws, it will then analyze why trade secret law is the best form of IP protection for magicians

Quaternion normalization in spacecraft attitude determination

Attitude determination of spacecraft usually utilizes vector measurements such as Sun, center of Earth, star, and magnetic field direction to update the quaternion which determines the spacecraft orientation with respect to some reference coordinates in the three dimensional space. These measurements are usually processed by an extended Kalman filter (EKF) which yields an estimate of the attitude quaternion. Two EKF versions for quaternion estimation were presented in the literature; namely, the multiplicative EKF (MEKF) and the additive EKF (AEKF). In the multiplicative EKF, it is assumed that the error between the correct quaternion and its a-priori estimate is, by itself, a quaternion that represents the rotation necessary to bring the attitude which corresponds to the a-priori estimate of the quaternion into coincidence with the correct attitude. The EKF basically estimates this quotient quaternion and then the updated quaternion estimate is obtained by the product of the a-priori quaternion estimate and the estimate of the difference quaternion. In the additive EKF, it is assumed that the error between the a-priori quaternion estimate and the correct one is an algebraic difference between two four-tuple elements and thus the EKF is set to estimate this difference. The updated quaternion is then computed by adding the estimate of the difference to the a-priori quaternion estimate. If the quaternion estimate converges to the correct quaternion, then, naturally, the quaternion estimate has unity norm. This fact was utilized in the past to obtain superior filter performance by applying normalization to the filter measurement update of the quaternion. It was observed for the AEKF that when the attitude changed very slowly between measurements, normalization merely resulted in a faster convergence; however, when the attitude changed considerably between measurements, without filter tuning or normalization, the quaternion estimate diverged. However, when the quaternion estimate was normalized, the estimate converged faster and to a lower error than with tuning only. In last years, symposium we presented three new AEKF normalization techniques and we compared them to the brute force method presented in the literature. The present paper presents the issue of normalization of the MEKF and examines several MEKF normalization techniques

Quaternion normalization in additive EKF for spacecraft attitude determination

This work introduces, examines, and compares several quaternion normalization algorithms, which are shown to be an effective stage in the application of the additive extended Kalman filter (EKF) to spacecraft attitude determination, which is based on vector measurements. Two new normalization schemes are introduced. They are compared with one another and with the known brute force normalization scheme, and their efficiency is examined. Simulated satellite data are used to demonstrate the performance of all three schemes. A fourth scheme is suggested for future research. Although the schemes were tested for spacecraft attitude determination, the conclusions are general and hold for attitude determination of any three dimensional body when based on vector measurements, and use an additive EKF for estimation, and the quaternion for specifying the attitude

Connectivity of proton and carbon spectra of the blue copper protein, plastocyanin, established by two-dimensional nuclear magnetic resonance

AbstractNMR studies of plastocyanin have centered on the ligands to the copper atom at the active site, particularly histidines-37 and -87. Heteronuclear (13C, 1H) J-connectivity spectroscopy has enabled cross assignment of 1H and 13C NMR resonances from the two copper-ligated histidines. In addition to providing assignments of the 13C resonances, the two-dimensional Fourier transform NMR results require the reversal of the original 1H NMR assignments to the ring protons of histidine-37. The line widths of the ring protons of histidine-87 are field-dependent leading to determination of the reduced lifetime of the proton on the Nδ atom (about 400 μs)

Fragment Approach to Constrained Density Functional Theory Calculations using Daubechies Wavelets

In a recent paper we presented a linear scaling Kohn-Sham density functional theory (DFT) code based on Daubechies wavelets, where a minimal set of localized support functions is optimized in situ and therefore adapted to the chemical properties of the molecular system. Thanks to the systematically controllable accuracy of the underlying basis set, this approach is able to provide an optimal contracted basis for a given system: accuracies for ground state energies and atomic forces are of the same quality as an uncontracted, cubic scaling approach. This basis set offers, by construction, a natural subset where the density matrix of the system can be projected. In this paper we demonstrate the flexibility of this minimal basis formalism in providing a basis set that can be reused as-is, i.e. without reoptimization, for charge-constrained DFT calculations within a fragment approach. Support functions, represented in the underlying wavelet grid, of the template fragments are roto-translated with high numerical precision to the required positions and used as projectors for the charge weight function. We demonstrate the interest of this approach to express highly precise and efficient calculations for preparing diabatic states and for the computational setup of systems in complex environments

An MME-based attitude estimator using vector observations

In this paper, an optimal batch estimator and filter based on the Minimum Model Error (MME) approach is developed for three-axis stabilized spacecraft. Three different MME algorithms are developed. The first algorithm estimates the attitude of a spacecraft using rate measurements. The second algorithm estimates the attitude without using rate measurements. The absence of rate data may be a result of intentional design or from unexpected failure of existing gyros. The third algorithm determines input-torque modeling error trajectories. All of the algorithms developed in this paper use attitude sensors (e.g., three-axis magnetometers, sun sensors, star trackers, etc.). Results using these new algorithms indicate that an MME-based approach accurately estimates the attitude, rate, and input torque trajectories of an actual spacecraft

Attitude Estimation Using Modified Rodrigues Parameters

In this paper, a Kalman filter formulation for attitude estimation is derived using the Modified Rodrigues Parameters. The extended Kalman filter uses a gyro-based model for attitude propagation. Two solutions are developed for the sensitivity matrix in the Kalman filter. One is based upon an additive error approach, and the other is based upon a multiplicative error approach. It is shown that the two solutions are in fact equivalent. The Kalman filter is then used to estimate the attitude of a simulated spacecraft. Results indicate that then new algorithm produces accurate attitude estimates by determining actual gyro biases

Two-dimensional concurrent HMQC-COSY as an approach for small molecule chemical shift assignment and compound identification

Chemical shift assignment is the first step toward the structure elucidation of natural products and other chemical compounds. We propose here the use of 2D concurrent HMQC-COSY as an experiment for rapid chemical shift assignment of small molecules. This experiment provides well-dispersed 1H–13C peak patterns that are distinctive for different functional groups plus 1H–1H COSY connectivities that serve to identify adjacent groups. The COSY diagonal peaks, which are phased to be absorptive, resemble 1H–13C HMQC cross peaks. We demonstrate the applicability of this experiment for rapidly and unambiguously establishing correlations between different functional groups through the analysis of the spectrum of a metabolite (jasmonic acid) dissolved in CDCl3. In addition, we show that the experiment can be used to assign spectra of compounds in a mixture of metabolites in D2O

P-Stereogenic, Bicyclic Phosphorus Heterocycles and Temporary Tether Strategies for the Synthesis of Complex Polyols

The development of atom-, redox-, and step-, and pot-economonical strategies for the streamlined synthesis of biologically active small molecules stands at the forefront of modern-day organic synthesis and early-stage drug discovery. In particular, those approaches that employ methods which allow for the reliable, predictable, and high-yielding coupling of a variety of both simple and elaborate chemical fragments to common core structural motifs represent some of the most efficient and versatile strategies to accomplish this goal. Since its first report in 2005, the use of phosphate triesters as temporary tethers has proven to be a powerful method for the facile formation of complex 1,3-skipped polyol-containing small molecules and biologically active natural products. The ability of phosphate tethers to impart differential olefin reactivity (exocyclic versus endocyclic), serve as temporary protecting groups, as well as latent leaving groups, and mediate several reactions in one-pot, sequential reactions continues to provide unique reactivity pathways to stereochemically rich intermediates, while minimizing chemical waste and the need for time-consuming purification. To date, phosphate-tether methods have served as the cornerstone in the total syntheses of dolabelide C, tetrahydrolipstatin, strictifolione, and Sch-725674, the formal synthesis of salicylihalimide A, and synthetic efforts toward lyngbouilloside and spirastrellolide B. Current efforts in the group are focused on the expansion and diversification of phosphate tether-mediated RCM strategies for the two-directional synthesis of biologically active small molecules. This thesis is dedicated to describing synthetic studies that augment previous work reported by our group involving P-stereogenic bicyclic phosphorus heterocycles and temporary tether strategies for the synthesis of complex polyols. Chapter 2 outlines a detailed study on the effects of stereochemical complexity, ring size, and olefin substitution on phosphate tether-mediated RCM. Studies focus on the formation of bicyclo[4.3.1]-, bicyclo[5.3.1]-, bicyclo[7.3.1]-, and bicyclo[8.3.1]phosphates, with a special emphasis on the factors that affect the success and stereochemical outcome of the P-tether mediated RCM event to form 10- and 11-membered bicyclic phosphates. Chapter 3 focuses on the synthesis of P-stereogenic bicyclo[4.3.1]phosphite-borane systems for the two-directional synthesis of complex polyols. These studies highlight the P-tether systems’ ability to facilitate chemoselective olefin functionalization, divergent oxidation strategies that allow access to the corresponding phosphate or thiophosphate, and a stereocontrolled, iterative SN2’-cuprate displacement protocol that marries the chemistry of phosphite borane tethers with that of their all oxygen-containing counterparts to generate polyol stereotetrads that were previously inaccessible via phosphate tether strategies alone. Chapter 4 presents the application of phosphate tether-mediated, one-pot sequential processes toward the total synthesis of 2S-sanctolide A and outlines plans for the application of the method to the total synthesis of 2R-sanctolide A and its analogs

The worldwide Protein Data Bank (wwPDB): ensuring a single, uniform archive of PDB data

The worldwide Protein Data Bank (wwPDB) is the international collaboration that manages the deposition, processing and distribution of the PDB archive. The online PDB archive is a repository for the coordinates and related information for more than 38 000 structures, including proteins, nucleic acids and large macromolecular complexes that have been determined using X-ray crystallography, NMR and electron microscopy techniques. The founding members of the wwPDB are RCSB PDB (USA), MSD-EBI (Europe) and PDBj (Japan) [H.M. Berman, K. Henrick and H. Nakamura (2003) Nature Struct. Biol., 10, 980]. The BMRB group (USA) joined the wwPDB in 2006. The mission of the wwPDB is to maintain a single archive of macromolecular structural data that are freely and publicly available to the global community. Additionally, the wwPDB provides a variety of services to a broad community of users. The wwPDB website at provides information about services provided by the individual member organizations and about projects undertaken by the wwPDB