Cohort Analysis Technique for Long-Term Manpower Planning: the Case of a Hong Kong Tertiary Institution

This paper considers the problem of long-term manpower planning on the number of teaching staff for the case of a tertiary institution—the City Polytechnic of Hong Kong (CPHK). Due to the high turnover experienced in recent years, it is found necessary to study the wastage pattern of staff, defined as the number of new appointees who have left CPHK employment, rather than simply addressing just the issue of strength (namely number in post). A cohort analysis technique is therefore applied to characterize statistically the wastage rate as related to the length of service of individual cohorts of staff, being groups of newcomers joining CPHK in the same periods of time. This results in a log-normal model, showing a significant cohort specific effect on the wastage behaviour. Extending this cohort analysis technique, together with double exponential smoothing forecasts, to future retention rates (1 — cumulative wastage rates), a long-term planning model is constructed to study the relation between expected yearly recruitment levels and the target manpower requirements for the future five-year planning horizon. While the idea and model developed here are generally applicable, the present computational results provide valuable decision supports for an actual case study, for CPHK in particular.     

The second and third virial coefficients of a two-dimensional gas

Numerical values of reduced second and third virial coefficients and their temperature derivatives are reported for a two-dimensional gas, for use in interpreting adsorption isotherms of monolayers on isoenergetic substrates. Correct values of the third virial coefficient have not been available before. Examples of earlier treatments of adsorption data are given to demonstrate that values of the higher virial coefficients are essential for adequate discussions of adsorption isotherms. When these are used the high-temperature adsorption isotherms of argon on graphitized carbon black in the monolayer region are completely described in terms of the unperturbed bulk-gas parameters.     

The application of equilibrium dialysis to the determination of drug-cyclodextrin stability constants

The equilibrium dialysis method was applied to the determination of drug-cyclodextrin stability constants using diflunisal and 2-hydroxypropyl--cyclodextrin (HPBCD) as a model system. Analysis of data showed the existence of a linear Scatchard plot, which is indicative of the formation of a 1:1 dlflunisal:LIPBCD complex. The stoichiometry of the complex was verified using the appropriate mass action law equation. The complexation constant (K_c) was 3801 ± 541 M^–1. The K_c obtained using the equilibrium dialysis method was comparable to that obtained using a potentiometric method (5564 ± 56 M^–1).     

Trifluoromethyl-containing pyrazolinyl (p-tolyl) sulfones: The synthesis and structure of promising antimicrobial agents

The regiospecific synthesis of a novel series of nine 4-phenyl- and 3-alkyl(aryl)-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-tosylpyrazoles (pyrazolinyl p-tolyl sulfones), as well as their antimicrobial activity against yeast, such as fungi, bacteria, and alga are reported. The 1-p-tosyl-2-pyrazolines were obtained from the cyclocondensation reaction of 3-phenyl- and 4-alkyl(aryl)-1,1,1-trifluoro-4-alkoxy-3-alken-2-ones, [where alkyl = H, Me and aryl are -C₆H₅, 4-CH₃C₆H₄, 4-OCH₃C₆H₄, 4-FC₆H₄, 4-ClC₆H₄, 4-BrC₆H₄,] with p-tosylhydrazine in a yield of 58-92% when toluene was employed as solvent. The best activity was obtained when the structure possessed a 4-fluorophenyl substituent linked at the carbon-3 of the pyrazoline ring. Subsequently, the dehydration reaction of 3-(4-fluorophenyl) substituted 2-pyrazoline with thionyl chloride/pyridine in benzene as solvent furnished the corresponding 1H-pyrazole in only a moderate yield (49%).     

Crystal structures of two macrocyclic diterpenoid photoproducts

The crystal structures of two macrocyclic diterpenoid photoproducts, the chemistry of which has been described in the preceding paper have been determined at 295 K.Compounds I (C₂₀H₂₆O₃) and II (C₂₂H₃₀O₅) are both orthorhombic, P2₁2₁2₁. In I. a = 24.18(1), b = 11.841 c=5.984(2) Å. Z=4. the structure being refined by least squares to a residual of 0.063 for 1234 “observed” reflections. For II. a = 24.30(1), b = 9.413(5). c = 9.149(5) Å. Z = 4 (R = 0.070, 982 “observed” reflections).     

Interlaboratory comparison of methods for the determination of incurred tilmicosin residues in bovine liver

The objective of this study was to compare 2 methods for the determination of tilmicosin residues in bovine liver samples. Three laboratories participated in the comparison of the 2 methods. The first method was described in a New Animal Drug Application (NADA 140-929), and the second was a modification of that method in which hexane was substituted for carbon tetrachloride in one cleanup step. Each of the 3 laboratories analyzed subsamples of 10 bovine livers containing incurred tilmicosin. Residues ranged from 2.3 to 81 ppm tilmicosin in the 10 liver samples with an 11.8% relative standard deviation obtained by using both methods. In addition, fortified-control liver tissue samples were analyzed concurrently with tissues containing incurred residues by using the modified method in one of the laboratories. The fortification levels ranged from 0.3 to 112 ppm, with recoveries ranging from 76 to 92%. The results from the 3 laboratories were comparable, indicating that the modified method was not only as effective as the original NADA method, but also more desirable because of the change to a less hazardous solvent.     

An optimal fourth-order family of methods for multiple roots and its dynamics

There are few optimal fourth-order methods for solving nonlinear equations when the multiplicity m of the required root is known in advance. Therefore, the principle focus of this paper is on developing a new fourth-order optimal family of iterative methods. From the computational point of view, the conjugacy maps and the strange fixed points of some iterative methods are discussed, their basins of attractions are also given to show their dynamical behavior around the multiple roots. Further, using Mathematica with its high precision compatibility, a variety of concrete numerical experiments and relevant results are extensively treated to confirm the theoretical development.     

Use of cyclohexanedimethanol as a nonflammable organic solvent for industrial scale reversed phase chromatography

This work demonstrates that cyclohexanedimethanol is an effective nonflammable organic solvent for the pilot scale reversed phase chromatography of recombinant apolipoprotein A-I(Milano). Cyclohexanedimethanol has low viscosity in water, enabling the use of conventional low pressure process scale chromatography columns and hardware. Results from pilot scale manufacturing using a 30 cm diameter CG71M packed column indicate that a 5.7 log reduction in E. coli host cell protein with >80% yield can be obtained for the purification of apolipoprotein A-I(Milano).