Sociology and Social Theory in Agent Based Social Simulation: A Symposium

A lengthy and intensive debate about the role of sociology in agent based social simulation dominated the email list simsoc@jiscmail.ac.uk during the autumn of 2000. The debate turned on the importance of models being devised to capture the properties of whole social systems and whether those properties should determine agent behaviour or, conversely, whether the properties of social systems should emerge from the behaviour and interaction of the agents and, if so, how that emergence should be represented. The positions of four of the main protagonists concerned specifically with the modelling issues are reprised and extended in this symposium.     

Development of high efficiency, multi-element CdZnTe detectors for portable measurement applications

We describe the development of detector arrays and electronics for large-volume, hand-held CdZnTe detectors with the same counting efficiency as portable NaI(Tl) detectors presently used for nuclear material measurement applications. The pulse-height resolution of the multi-element detectors is at least three times better than NaI(Tl) over a wide energy range (from 100 keV to several MeV), enabling more accurate measurements of gamma-rays emitted by special nuclear material. Arrays of up to eight coplanar grid detectors can be combined to make detectors ranging in size from 4 to 14 cm³. Because the number of spectroscopy channels is small, low-power, hand-held detectors can be manufactured with conventional printed circuit board technology, thus keeping the cost of multi-element detectors to a minimum. The design and performance of an 8-element detector is presented.     

Hexamethoxycyclopropane

Hexamethoxycyclopropane, obtained by reaction of lithiopentamethoxycyclopropane with dimethyl peroxide, decomposes at 200°C to dimethoxycarbene and tetramethoxyethylene.     

On the natural width of the hypersatellite lines

The natural width of a hypersatellite line (K ^?2→K ^?1 L ^?1 transition) has been measured for the first time. In the case of Cu (Z=29) this width has been found equal toΓ = 5 eV, i.e. much larger than that of the diagram (K ^?1→L ^?1) line. This result follows a proposed empirical law assuming this width to be equal to 3Γ _K+Γ_L.     

Cationic di-iron complexes {[η-C5Fe(CO)2]2[μ-(CnH2n1)]}+

The reactions of the complexes [CpFe(CO)₂]₂[μ-(CH₂)_n with Ph₃CPF₆ yield cationic di-iron complexes of the type {[CpFe(C     

A rapid scan interferometer for near millimetre wavelength radiometry

A near millimetre wavelength radiometer has been constructed, based on a rapid scan polarising interferometer. The design and procedure are described, and some results are presented.     

Chlorophyll fluorescence biosensor for the detection of herbicides

A biosensor is described for the detection of triazine and phenylurea herbicides in drinking water by kinetic measurements of endogenous chlorophyll fluorescence in isolated chloroplasts from higher plants. The pocket-size device uses a diode laser for simultaneous excitation of sample and reference channels, and photodiodes for detection of the emitted light. The biological material can be supplied as a freeze-dried powder, stable for 21 days at room temperature, for 6 weeks at 4 ( degrees )C or for at least 9 months at -20 ( degrees )C. The detection of 0.1 microg/l of a single herbicide, as required by European Community legislation on drinking water quality, can be achieved without prior extraction of the sample.