The efficient frontier for spot and forward purchases: an application to electricity

A local electricity distribution company (LDC) can reduce its exposure to the inherent risks of spot-price volatility and uncertain future demand via forward contracts. Management's problem is to determine the optimal forward-contract purchase. We propose a practical three-stage approach for dealing with the problem. The first stage determines an optimal purchase by solving a cost-constrained risk-minimization problem. The second stage derives the efficient frontier of tradeoffs between expected cost and cost risk from the first-stage solution, at various bounds on the expected cost. The optimal solution is found by melding the frontier with management's risk preferences. In the third stage, the model's parameters are estimated from data typically available to an LDC and used to determine its forward-contract purchase.     

Fluctuating Carbonaceous Networks with a Persistent Molecular Shape: A Saddle‐Shaped Geodesic Framework of 1,3,5‐Trisubstituted Benzene (Phenine)

A saddle‐shaped macromolecule has been synthesized. The molecule was designed as a geodesic saddle with 1,3,5‐trisubstituted benzene (named phenine) as the fundamental unit. The phenines were woven into a polygonal framework that was composed of 168 sp²‐hybridized carbon atoms. The saddle‐shaped structure with unique symmetry showed atypical conformational changes. The biaryl linkages in this molecule had a small energy barrier for rotation, and these structural fluctuations resulted in seven ¹H NMR resonances representing 84 aromatic hydrogen atoms. Nevertheless, the overall saddle shape of the molecule was persistent, and the “up” and “down” orientations of phenine moieties circulated to give average ¹H resonances. The structural characteristics of this molecule, including the anomalous entropy‐driven dimerization, may deepen our understanding of defect‐rich graphitic sheets.     

Synthesis of dl-coriolin

The total synthesis of dl-coriolin has been achieved in a stereoselective way. The key tricyclic intermediate was synthesized from dicyclopentadiene through a route which involved an S_N2 reaction at a neopentylic position.     

Determination of pyrimethamine in animal tissue and egg by liquid chromatography with fluorescence detection

A sensitive and selective liquid chromatographic (LC) assay was developed to determine the concentration of pyrimethamine in animal tissue and egg by fluorescent derivative. Animal samples were extracted with acetonitrile, centrifuged, and purified by hexane. Fluorescent derivatization was performed by reacting pyrimethamine with chloroacetaldehyde and subjected to LC with fluorescence detection (excitation wavelength 300 nm, emission wavelength 420 nm). The limit of detection was 10 ng/g (10 ppb) and the standard calibration curve was linear in the range of 1-100 ppb (0.01-1 ng/10 microL). Recoveries from samples fortified at levels of 0.1 and 1 ppm (microg/g) were 61.0-77.4 and 65.5-81.2%, respectively. The method was applied to the monitoring of marketed samples. Pyrimethamine was not determined in any of the 70 samples: 20 swine muscle; 20 chicken muscle; 10 chicken liver; and 20 egg.     

Magnetic uni- and tri-axial grain-orientation in superconductors with layered structures

We report the grain-orientation effects under a modulated rotation magnetic field for Y-based cuprate superconductors and LaFeAsO (La1111). Tri-axial orientation has been successfully achieved only for orthorhombic Y₂Ba₄Cu₇O_y and YBa₂Cu₄O₈ powders without a twin microstructure, while separation of three crystallographic axes could not be observed in twinned YBa₂Cu₃O_y (Y123) and tetragonal La1111 powders. The morphology of grains, in addition to the symmetry of crystal structures, seriously affects the degrees of tri-axial orientation, which means that the control of twin microstructures is required for the tri-axial magnetic orientation in Y123.     

LP narrowing: A new strategy for finding all solutions of nonlinear equations

An efficient algorithm is proposed for finding all solutions of systems of n nonlinear equations. This algorithm is based on interval analysis and a new strategy called LP narrowing. In the LP narrowing strategy, boxes (n-dimensional rectangles in the solution domain) containing no solution are excluded, and boxes containing solutions are narrowed so that no solution is lost by using linear programming techniques. Since the LP narrowing is very powerful, all solutions can be found very efficiently. By numerical examples, it is shown that the proposed algorithm could find all solutions of systems of 5000-50,000 nonlinear equations in practical computation time.     

Relationship between acetabular labrum evaluation by using radial magnetic resonance imaging and progressive joint space narrowing in mild hip dysplasia

OBJECTIVE: The aim of this study was to investigate the relationship between abnormal acetabular labrum depicted by radial magnetic resonance and progressive joint space narrowing (JSN) of hip dysplasia. METHODS: Subjects were 23 joints [21 patients; mean age: 35.1 years (16-53 years)] that had acetabular dysplasia with lateral center-edge angle of Wiberg (CE angle) greater than 5 degrees and smaller than 25 degrees (mean, 16.4 degrees ), which did not show any arthrotic changes on plain radiograms and were followed up for 3 years or longer. Radial images of acetabular labrum were classified into three stages. RESULTS: Progression of JSN was not significantly related to CE angle but to progression of MRI stage (P=.006). In multivariate analysis, one rank progression of MRI stage was significantly associated with progression of JSN (adjusted OR=11.41, 95% CI: 1.51-86.24, P=.018). CONCLUSION: Our findings showed that in patients whose acetabular dysplasia has 5-25 degrees CE angle, MRI staging based on radial MRI is a better factor for prediction of progression of JSN than CE angle.