SIMULATION AS AN AID TO DECISION MAKING IN A WATER UTILITY1

ABSTRACT. Middle and high management levels within water utilities would find their decision making activities greatly enhanced if provided with a set of techniques having the following characteristics: (1) the ability to procure information and knowledge about real-life systems, (2) the ability to promote analysis of the real life system and (3) the capacity to gauge the impact of decisions. A model/simulation is presented, having the capability to mime operational aspects of water supply systems. The simulation produces time series of what are considered relevant operational variables. These series are amenable to analysis of both static and dynamic effects of alternative policies, changing environmental conditions and varying parametric specifications. Because of its modular structure and the ad hoc programming language utilized, it offers great flexibility. The model/simulation allows extensions, deletions and modifications without consequent reformulation or extensive reprogramming. It performs a number of statistical tests useful for its own verification and validation. Also available are a suggested methodology and procedures for model use, possible difficulties with data gathering and operation, plus an idea of what cannot be done with the currently extant model version.     

Effect of formulation on the behavior of 1,3-dichloropropene in soil

The fumigant 1,3-dichloropropene (1,3-D) has been identified as a partial replacement for methyl bromide (CH3Br) in soil fumigation. 1,3-Dichloropropene is formulated for soil fumigation as Telone II (Dow AgroSciences, Indianapolis, IN) for shank application and as an emulsifiable concentrate (EC) (Telone EC or InLine; Dow AgroSciences) for drip application. This study investigated the effect of formulation on the phase partitioning, transformation rate, and volatilization of 1,3-D isomers. Air-water partitioning coefficients (K(H)) were slightly higher for Telone II than for Telone EC, presumably due to the higher apparent water solubility of the EC formulation. Sorption of 1,3-D isomers in two soils was not affected by formulation. Formulation had no significant effect on the rate of 1,3-D transformation in water or soil. In general, differences in the rate of 1,3-D transformation and phase partitioning due to formulation as Telone II or Telone EC were very small. Thus, the effect of formulation on 1,3-D fate may be ignored in transformation and phase partition of 1,3-D in water and soil. Packed soil columns without plastic tarp indicated that with relatively shallow subsurface (10 cm) drip application of Telone EC, emission of 1,3-D isomers was more rapid and produced greater maximum instantaneous flux than deeper (30 cm) shank injection of Telone II. Both application methods resulted in the same cumulative emissions for both isomers, 45% for (E)-1,3-D and approximately 50% for (Z)-1,3-D. These results suggest that for drip application of fumigants to be effective in reducing emissions, the fumigant must be applied at sufficient depths to prevent rapid volatilization from the soil surface if the water application rate does not sufficiently restrict vapor diffusion.     

Environmental marketing's new relationship with corporate environmental management

Issues of environmental marketing track back to issues of environmental management—i.e., to issues of overall corporate environmental commitment and responsibility. It is absolutely essential that a commitment to corporate environmental improvement be in place before an environmental marketing program is launched. Additionally, marketers can and should play a central role in the greening of the corporation. The marketer brings at least two important skills or strengths to the environmental improvement process—strengths of perspective and strengths of skill set.     

A DYNAMIC BACTERIAL MODEL FOR A RECREATIONAL LAKE1

ABSTRACT A dynamic mathematical model was constructed to examine bacterial contamination problems affecting Ford Lake, a small recreational lake in Southeast Michigan. The model was calibrated and verified using summer dry weather averaged data and data from three wet weather surveys. Model simulations demonstrated that the major bacterial contamination was attributable to storm related perturbations affecting two point sources: the Huron River and the Ypsilanti Sewage Treatment Plant. The nonpoint source contribution was relatively minor. The Model is currently being used by the State of Michigan Department of Natural Resources as a management tool for assessing the effectiveness of planned pollution abatement strategies     

Redistributing the world's wealth: Cancun ‘summit’ discord

The aim of the North-South ‘summit’ conference in 1981 was to bridge the wealth gap between the few industrial nations and the hundred-odd poor countries. Unfortunately no firm proposals materialized. The rich nations refused to increase their aid transfers to the developing countries or to correct the growing inequalities in world trade. The multiplication of wealth is the basic concern of the North in an era of recession and unemployment. The division of wealth is an urgent necessity for the South, but their demands for a global reallocation of resources remained unmet. The gap is likely to widen considerably in future.     

Organophosphate flame retardants and plasticizers in indoor air

Analytical methods were developed for a broad range of organophosphate flame retardants and plasticizers in indoor air. Screening was performed of various indoor environments at 12 locations in and around Zurich, Switzerland. Method recoveries ranged from 62% for triphenyl phosphate to 100% for tris(2-ethylhexyl) phosphate. Tris(2-chloro-isopropyl) phosphate was found in the highest concentration (260 ng/m(3)) mainly in cars and furniture stores. Tris(2-ethylhexyl) phosphate and triphenyl phosphate, both up to 3.4 ng/m(3), were also detected in quantifiable concentrations at several sites. Tris(1,3-dichloroisopropyl) phosphate, tricresyl phosphate and tri(2-butoxyethyl) phosphate were below the limit of quantification in all samples. The results of the risk assessment indicate that the observed concentrations are below the predicted threshold for human health effects.     

Beetle adhesive hairs differ in stiffness and stickiness: in vivo adhesion measurements on individual setae

Leaf beetles are able to climb on smooth and rough surfaces using arrays of micron-sized adhesive hairs (setae) of varying morphology. We report the first in vivo adhesive force measurements of individual setae in the beetle Gastrophysa viridula, using a smooth polystyrene substrate attached to a glass capillary micro-cantilever. The beetles possess three distinct adhesive pads on each leg which differ in function and setal morphology. Visualisation of pull-offs allowed forces to be measured for each tarsal hair type. Male discoidal hairs adhered with the highest forces (919?±?104?nN, mean?±?SE), followed by spatulate (582?±?59?nN) and pointed (127?±?19?nN) hairs. Discoidal hairs were stiffer in the normal direction (0.693?±?0.111?N?m^?1) than spatulate (0.364?±?0.039?N?m^?1) or pointed (0.192?±?0.044?N?m^?1) hairs. The greater adhesion on smooth surfaces and the higher stability of discoidal hairs help male beetles to achieve strong adhesion on the elytra of females during copulation. A comparison of pull-off forces measured for single setae and whole pads (arrays) revealed comparable levels of adhesive stress. This suggests that beetles are able to achieve equal load sharing across their adhesive pads so that detachment through peeling is prevented.     

Honeybees learn floral odors while receiving nectar from foragers within the hive

Recent studies showed that nectar odors brought back by honeybee foragers can be learned associatively inside the hive. In the present study, we focused on the learning abilities of bees, which directly interact via trophallaxis with the incoming nectar foragers: the workers that perform nectar-receiving tasks inside the hive. Workers that have received food directly from foragers coming back from a feeder offering either unscented or scented sugar solution [phenylacetaldehyde (PHE) or nonanal diluted] were captured from two observational hives, and their olfactory memories were tested using the proboscis extension response paradigm. Bees that have received scented solution from incoming foragers showed significantly increased response frequencies for the corresponding solution odor in comparison with those that have received unscented solution. No differences in the response frequencies were found between food odors and colonies. The results indicate that first-order receivers learn via trophallaxis the association between the scent and the sugar solution transferred by incoming foragers. The implications of these results should be considered at three levels: the operational cohesion of bees involved in foraging-related tasks, the information propagation inside the hive related to the floral type exploited, and the putative effect of these memories on future preferences for resources.     

The development of self‐efficacy during aviation training

Given that self‐efficacy has been shown to be positively related to training outcomes, a better understanding of factors that affect self‐efficacy in complex training contexts is needed. This study examined the development of self‐efficacy in a flight‐training programme. Results indicate that training performance and self‐esteem predicted self‐efficacy for post‐training flight performance. Furthermore, prior flight experience moderated the relationships between training performance and self‐efficacy, and between self‐esteem and self‐efficacy. Implications regarding the development of self‐efficacy and the design of training programmes are discussed. Copyright © 2000 John Wiley & Sons, Ltd.