Horizon Valuations for Mathematical Programming in Financial Planning

Using a linear programming model for the financial planning of an organization requires the specification of a horizon date and a valuation of the firm at that date. Given perfect information about future opportunities, an exact valuation procedure should lead to the same optimal solution of the model regardless of the choice of horizon date. Even in the absence of perfect information, conventional valuations fall far shorter of this ideal than they need to. It is shown that for a modest increase in the size of the linear programme, better valuations can be achieved and, most importantly, valuations which consider the impact on the value of the firm of post horizon constraints and liabilities as well as post-horizon opportunities.     

Studies related to the synthesis of maytansinoids.

Two approaches to the partial synthesis of C₁–C₅ of a bis-nor maytansinoid $\text{1}$ have been investigated starting on the one hand with (S)-(?)-malic acid and on the other, with D-(+)-ribonolactone.     

Preparation and x-ray structure of 1,4,2,3,5,6-Dithiatetrazine

Reaction of sulfur dichloride with sym-EtO₂CNHNHCO₂Et 1 gives the title ring system which has been characterised by microanalyses, nmr, and X-Ray crystallography. The X-ray structure of S₂[N(CO₂Et)]₄ 2 reveals that the S₂N₄ ring adopts a chair conformation with all four ester groups in pseudo-axial positions. Bond lengths and angles are compared with 1 and S₄(NR)₂.     

Susceptibility to intraspeech spread of masking in listeners with sensorineural hearing loss

Previous research with speechlike signals has suggested that upward spread of masking from the first formant (F 1) may interfere with the identification of place of articulation information signaled by changes in the upper formants. This suggestion was tested by presenting two-formant stop consonant--vowel syllables varying along a/ba--/da/--/ga/ continuum to hearing-impaired listeners grouped according to etiological basis of the disorder. The syllables were presented monaurally at 80 dB and 100 dB SPL when formant amplitudes were equal and when F 1 amplitude was reduced by 6, 12, and 18 dB. Noise-on-tone masking patterns were also generated using narrow bands of noise at 80 and 100 dB SPL to assess the extent of upward spread of masking. Upward spread of masking could be demonstrated in both speech and nonspeech tasks, irrespective of the subject's age, audiometric configuration, or etiology of hearing impairment. Attenuation of F 1 had different effects on phonetic identification in different subject groups: While listeners with noise-induced hearing loss showed substantial improvement in identifying place of articulation, upward spread of masking did not consistently account for poor place identification in other types of sensorineural hearing impairment.     

Luminescence properties of Tb-activated yttrium gallium garnet phosphors

Comparison of luminescence properties between electron-excited and uv-excited yttrium gallium garnet: Tb phosphors is reported. Although the thermoluminescence and phosphorescence in both cases are quite alike once traps are filled, an apparent difference in the behavior of trap filling has been observed. Small addition of V₂O₃ to these phosphors revealed a unique effect on luminescence properties either with the electron excitation or with the uv excitation.     

Electrochemical studies on three polar diruthenium(II,III) complexes

Electrochemical studies on a new class of diruthenium(II,III) compounds were done. The complexes having a polar arrangement of ligands across the diruthenium unit in Ru₂Cl(hp)₄(Hhp), Ru₂Cl(chp)₄ and Ru₂Cl(PhNpy)₄ where Hhp, Hchp and PhNHpy are 2-hydroxypyridine, 6-chloro-2-hydroxypyridine, and 2-anilinopyridine, respectively, undergo two or more oxidations and reductions. The metal centered reductions in the range of +0.1 to ?0.75 V and oxidations in the range +0.5 to +1.2 V are discussed and compared with diruthenium carboxylato and amidato complexes.     

Novel non-aqueous Fe(III)/Fe(II) redox couple for the catalytic oxidation of hydrogen sulfide to sulfur by air

A series of Fe(III) salts and organic solvents have been screened to develop novel non-aqueous catalysts for the conversion of H2S to sulfur. FeCl3/95% N-methylpyrrolidinone/5% H2O was found to be a most efficient non-aqueous system. The process chemistry, the proposed mechanism of catalytic oxidation of H2S, and the electrochemistry are discussed.     

Solution-phase parallel synthesis of a pyridinium pyrazol-3-olate inner salt library using a three-component reaction

We present here the discovery of a novel, versatile, multicomponent reaction leading to various 4-[4-(pyridinium-1-yl)-2,5-dioxo-2,5-dihydro-1H-pyrrol-3-yl]-2H-pyrazol-3-olate inner salts. The structure of the unusual zwitterionic inner salts was elucidated, and the scope of the novel reaction was investigated. After rapid optimization, the reaction was adapted to parallel synthesis, and an 800-membered compound library was produced.     

Spontaneous formation of vesicles of diblock copolymer EO6BO11 in water: a SANS study

Small angle neutron scattering (SANS) is used to study the structures formed in water by a diblock copolymer EO6BO11 (having 6 ethylene oxide, EO, and 11 butylene oxide, BO, units). The data show that polymer solutions over a broad concentration range (0.05-20 wt %) contain vesicular structures at room temperature. Interestingly, these vesicles could be formed without any external energy input, such as extrusion, which is commonly required for the formation of other block copolymer or lipid vesicles. The EO6BO11 vesicles are predominantly unilamellar at low polymer concentrations, whereas at higher polymer concentrations or temperatures there is a coexisting population of unilamellar and multilamellar vesicles. At a critical concentration and temperature, the vesicular structures fuse into lyotropic arrays of planar lamellar sheets. The findings from this study are in broad agreement with the work of Harris et al. (Langmuir, 2002, 18, 5337), who used electron microscopy to identify the vesicle phase in the same system.