EXPERIMENTAL EVALUATION OF MULTIPLE CRITERIA DECISION MODELS FOR APPLICATION TO WATER RESOURCES PLANNING1

ABSTRACT: A research project was undertaken for the U.S. Army Corps of Engineers to determine the relative utility and effectiveness of four well-known multicriteria decision making (MCDM) models for applications in realistic water resources planning settings. A series of experiments was devised to examine the impact of rating and ranking procedures on the decision making behavior of users (e.g., planners, managers, analysts, etc.) when faced with situations involving multiple evaluation criteria and numerous alternative planning projects. The four MCDM models tested were MATS-PC, EXPERT CHOICE, ARIADNE, and ELECTRE. Two groups of analysts and decision makers were tested. One group consisted of experienced U.S. Army Corps planners, while the other was comprised of graduate students. Based on a series of nonparametric statistical tests, the results identified EXPERT CHOICE as the preferred MCDM model by both groups based largely on ease of use and understandability. ARIADNE fostered the largest degree of agreement within and among the two groups of individuals tested. The tests also lend support to the claim that rankings are not affected significantly by the choice of decision maker (i.e., who uses any of these MCDM models) or which of these four models is used.     

Effect of ammonia on the survival of Zacco platypus (Temminck and Schlegel) at each developmental stage

The survival rates were studied of fertilized eggs, larvae, fry, and adults of pale chub Zacco platypus (Temminck and Schlegel) exposed to various concentrations of ammonia. There was a decrease in hatching rate and an increase in deformed alevins at a concentration of 0.9 mg liter(-1) of ammonia. All alevins were deformed at a concentration of 1.6 mg liter(-1) of ammonia and no eggs hatched at a concentration of 3.1 mg liter(-1) of ammonia. No larvae survived for 84, 24 and 12 h at concentrations of 1.2, 2.0 and 4.7 mg liter(-1) of ammonia, respectively. Eighty percent of the fry died after 168 h and no fry survived for 24 h at concentrations of 1.6 and 2.1 mg liter(-1) of ammonia, respectively. Eighty percent of the adults died after 24 h and no adult survived for 12 h at concentrations of 1.0 and 1.9 mg liter(-1), respectively. Larger adults were the most susceptible to ammonia. The order of resistance to ammonia was eggs, fry, larvae, and adults.     

Intrauterine mediastinal teratoma associated with non-immune hydrops fetalis

We describe a rare case of non-immune hydrops fetalis caused by mediastinal teratoma. The sonographic appearance was that of a mixed cystic and solid mass in the antero-superior mediastinum. The teratoma, on post mortem, extended cranially to the upper part of the thyroid, exerting pressure and causing deviation of the trachea, oesophagus, and aortic arch. The pathogenesis of non-immune hydrops fetalis suggests obstruction of venous return caused by this tumour.     

Prenatal sonographic signs of possible fetal genital anomalies

The sonographic markers of female and male external genitalia have been documented in early and late gestation. The aim of the present study was to report our experience of possible sonographic markers of fetal genital anomalies. Sonography was performed with a vaginal probe in early gestation and an abdominal sector scanner in advanced gestation. The following genital anomalies were observed: hypospadias, epispadias, ambiguous genitalia, and testicular feminization or Smith-Lemli-Opitz syndrome. It is therefore concluded that prenatal diagnosis of some genital anomalies is now possible.     

Clues and pitfalls in the early prenatal diagnosis of ‘late onset’ infantile polycystic kidney

Infantile polycystic kidney disease (IPKD) is an autosornal recesive inherited disorder, IPKD has been previously diagnosed by us as early as the 14th week of gestation. ‘Late onset’ (third trimester) IPKD has been previously described by several authors. We present here a case of intrauterine detection of ‘late onset’ IPKD, suggesting that elongated hyperechogenic kidneys (with normal transverse and anteroposterior diameters) should be considered as an early sign of ‘late onset’ presenting IPKD.