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.     

DDLm: A New Dictionary Definition Language

A previous paper [Spadaccini and Hall J. Chem. Inf. Model. doi:10.1021/ci300074v] details extensions to the STAR File [Hall J. Chem. Inf. Comput. Sci.1991, 31, 326-333] syntax that will improve the exchange and archiving of electronic data. This paper describes a dictionary definition language (DDLm) for defining STAR File data items in a domain dictionary. A dictionary that defines the ontology and vocabulary of a discipline is built with DDLm, which is itself implemented in STAR, and is extensible and machine parsable. The DDLm is semantically rich and highly specific; provides strong data typing, data enumerations, and ranges; enables relationship keys between data items; and uses imbedded methods written in dREL [Spadaccini et al. J. Chem. Inf. Model. doi:10.1021/ci300076w] for data validation and evaluation and for refining data definitions. It promotes the modular definition of the discipline ontology and reuse through the ability to import definitions from other local and remote dictionaries, thus encouraging the sharing of data dictionaries within and across domains.     

A multistage linearisation approach to a four-dimensional hyperchaotic system with cubic nonlinearity

This paper reports on a new multistage extension of the successive linearisation method to a four-dimensional chaotic system that generates various complex attractors for different parameter values. The solutions are found by subdividing the domain into several intervals in which the linearisation method is used to find approximate solutions that are then matched across all the intervals. The solutions and phase portraits for the cyclic and chaotic cases are given. Finally we compare this approach to the Runge?CKutta based ode45 solver and other results in the literature to show that the multistage linearisation method gives accurate results.     

Monomeric azaheterofullerene derivatives RC59N: influence of the R moiety on spectroscopic and photophysical properties

We have synthesised nine monomeric azaheterofullerene (AZA) derivatives, RC(59)N, with a wide variety of different side chains R and investigated their spectroscopic and photophysical properties in toluene and o-dichlorobenzene (ODCB). Measurements include their ground-state absorption spectra, molar absorption coefficient (epsilon(G)), fluorescence spectra, fluorescence quantum yields (Phi(F)), singlet-state lifetimes (tau(F)), triplet-state absorption spectra, triplet molar absorption coefficients (epsilon(T)), singlet oxygen (Phi(Delta)), and triplet state (Phi(T)) quantum yields. The replacement of a carbon by a nitrogen atom in the C(60) sphere strongly affects most of the spectroscopic and photophysical properties. The chemical nature of the R moiety has definite effects on these properties in contrast with minor effects on the chemical nature of the addends in [6,6]-ring bridged monoadduct methano[60]fullerene derivatives. These effects concern properties of the ground state, singlet excited state, and triplet states of our nine RC(59)N derivatives and in particular the values of photophysical parameters epsilon(G), epsilon(T), Phi(Delta), and Phi(T), which are significantly lower than those of analogous monoadduct [6,6]-ring bridged methano[60]fullerene derivatives.     

One-pot synthesis of MWW zeolite nanosheets using a rationally designed organic structure-directing agent

A new material MIT-1 comprised of delaminated MWW zeolite nanosheets is made in a one-pot synthesis using a rationally designed organic structure-directing agent (OSDA). The OSDA consists of a hydrophilic head segment that resembles the OSDA used to synthesize the zeolite precursor MCM-22(P), a hydrophobic tail segment that resembles the swelling agent used to swell MCM-22(P), and a di-quaternary ammonium linker that connects both segments. MIT-1 features high crystallinity and surface areas exceeding 500 m² g^–1, and can be synthesized over a wide synthesis window that includes Si/Al ratios ranging from 13 to 67. Characterization data reveal high mesoporosity and acid strength with no detectable amorphous silica phases. Compared to MCM-22 and MCM-56, MIT-1 shows a three-fold increase in catalytic activity for the Friedel–Crafts alkylation of benzene with benzyl alcohol.     

Laser and synchrotron-based sources for excited state intramolecular dynamics studies

Energy ranges and time scales for excitation and relaxation of intramolecular processes are discussed and compared with the operational characteristics of laser and synchrotron radiation sources. The basic physics of synchrotron radiation and undulator emission is presented. It is shown how undulators can be used to generate short wavelength harmonics. Free electron lasers of the Compton and Raman scattering types and the associated electron beam sources are described. The properties and applications of free electron lasers are reviewed.     

Resurrection and Reactivation of Acetylcholinesterase and Butyrylcholinesterase

Organophosphorus (OP) nerve agents and pesticides present significant threats to civilian and military populations. OP compounds include the nefarious G and V chemical nerve agents, but more commonly, civilians are exposed to less toxic OP pesticides, resulting in the same negative toxicological effects and thousands of deaths on an annual basis. After decades of research, no new therapeutics have been realized since the mid-1900s. Upon phosphylation of the catalytic serine residue, a process known as inhibition, there is an accumulation of acetylcholine (ACh) in the brain synapses and neuromuscular junctions, leading to a cholinergic crisis and eventually death. Oxime nucleophiles can reactivate select OP-inhibited acetylcholinesterase (AChE). Yet, the fields of reactivation of AChE and butyrylcholinesterase encounter additional challenges as broad-spectrum reactivation of either enzyme is difficult. Additional problems include the ability to cross the blood brain barrier (BBB) and to provide therapy in the central nervous system. Yet another complication arises in a competitive reaction, known as aging, whereby OP-inhibited AChE is converted to an inactive form, which until very recently, had been impossible to reverse to an active, functional form. Evaluations of uncharged oximes and other neutral nucleophiles have been made. Non-oxime reactivators, such as aromatic general bases and Mannich bases, have been developed. The issue of aging, which generates an anionic phosphylated serine residue, has been historically recalcitrant to recovery by any therapeutic approach—that is, until earlier this year. Mannich bases not only serve as reactivators of OP-inhibited AChE, but this class of compounds can also recover activity from the aged form of AChE, a process referred to as resurrection. This review covers the modern efforts to address all of these issues and notes the complexities of therapeutic development along these different lines of research.