On the analysis and solution of certain geographical optimal covering problems

The article formulates, analyses and suggests solutions to some optimal covering problems that often arise in association with geographical coordinates, albeit their mathematical form may be detached from this background. It shows that under a general formulation no favorable mathematical properties can be deduced beyond the “center of gravity”, and thus that computational algorithms are seemingly the best resort for resolving the problem. An algorithm that is based on the steepest descent approach and that exploits the “center of gravity” property is devised, and is shown as a detector of local minima points. A release from the “locality trap” is provided by a stochastic algorithm.Every part of the paper is accompanied by illustrative examples, either of an analytical nature on a segment of the real line or of a numerical nature by computer programs.     

Topochemistry. Part XXXIX. The Solid-state Photochemistry of some 2′-Nitrochalcones

It is shown that the specific pathway of a complex photochemical reaction in the solid state is governed by the molecular conformation and its retention, and by the molecular packing. 2′-Nitrochalcone and those of its derivatives which are isomorphous with it display the s-trans conformation in the solid state and yield indigos upon irradiation. However, this conformation is not sufficient to ensure photoreactivity: thus the s-trans-4-bromo-derivative does not yield indigo. The same derivative in the s-cis conformation (in a second crystal form) has a crystal structure similar to that of the parent compound, and also does not yield indigo.     

Correlates of employee lateness: Some theoretical considerations.

Using hypothesis-driven meta-analytic procedures on 30 samples containing 118 correlations, researchers examined competing models of the relationship between lateness and assorted work-related variables. Consistent with a progression withdrawal model, the mean corrected lateness-absence correlation, .40, was found to be higher than the lateness-turnover correlation, .27. Hypotheses regarding the relationships between lateness and attitudes, performance, and demographics were generally supported. Methodological issues, including the need for longitudinal designs in the field and the inclusion of other moderators such as organizational and personality variables, were discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal energy storage in columns packed with crosslinked polyethylene tubes

An energy storage system based on solid-solid phase transition of crosslinked polyethylene was constructed and tested. The energy storage unit consisted of a column packed with crosslinked polyethylene tubes. The solid-solid phase transition enables heat transfer by direct contact between the form-stable polymer and the hot (cold) fluid. A theoretical model for the simulation of this system was developed. The heating-cooling characteristics of the energy storage system were simulated by the model, using measured thermodynamic properties of the crosslinked polyethylene. The potential of various crosslinked polyethylene materials for energy storage applications will depend on sufficient high-temperature stability.     

The effect of threat upon interpersonal bargaining.

The effect of threat on the process of bargaining was investigated experimentally by asking Ss to imagine proceeding across a certain route on a map and having various experiences. Threat was seen to affect bargaining detrimentally. In that regard, cooperative ventures were seen to be safer than competitive ones. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relation between limb dominance, acceptance of disability, and the phantom limb phenomenon.

Examined 2 hypotheses regarding the phantom limb sensation (PLS). One predicted that the frequency of PLS would be greater for the dominant than the nondominant limb. The 2nd hypothesized that there is an inverse relation between acceptance of the disability and frequency of PLS. 18 double-amputees who had lost 2 homologous limbs while in military service were administered questionnaires examining limb dominance, frequency of the PLS, and acceptance of disability. Results confirm only the 1st hypothesis. The PLS is discussed in light of the present findings, and it is concluded that the role of physiological factors seems to be clearer than that of psychological ones. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)