Current software cost estimation models, such as the 1981 Constructive Cost Model (COCOMO) for software cost estimation and its 1987 Ada COCOMO update, have been experiencing increasing difficulties in estimating the costs of software developed to new life cycle processes and capabilities. These include non-sequential and rapid-development process models; reuse-driven approaches involving commercial off-the*shelf (COTS) packages, re-engineering, applications composition, and applications generation capabilities; object-oriented approaches supported by distributed middleware; and software process maturity initiatives. This paper summarizes research in deriving a baseline COCOMO 2.0 model tailored to these new forms of software development, including rationale for the model decisions. The major new modeling capabilities of COCOMO 2.0 are a tailorable family of software sizing models, involving Object Points, Function Points, and Source Lines of Code; nonlinear models for software reuse and re-engineering; an exponentdriver approach for modeling relative software diseconomies of scale; and several additions, deletions and updates to previous COCOMO effort-multiplier cost drivers. This model is serving as a framework for an extensive current data collection and analysis effort to further refine and calibrate the model's estimation capabilities.

PurposeThe purpose of this paper is to describe the components of a sustainability transdisciplinary education model (STEM), a contemporary approach linking art, science, and community, that were developed to provide university and K‐12 students, and society at large shared learning opportunities. The goals and application of the STEM curriculum will be discussed.Design/methodology/approachThe STEM integrates the sciences, arts and aesthetics, and the university with the greater New Britain community, and beyond. Academic areas included geography, environmental science, communication, art history, aesthetics, and teacher education. The transdisciplinary methodology was integrated in a learner‐centered design. To achieve a cycle of community engagement regarding sustainability, university students were placed within the greater New Britain community. This included interaction with K‐12 urban public schools, the New Britain Museum of American Art (NBMAA), numerous nongovernmental organizations, state and federal governmental elected officials, and the general public.FindingsAs a result of the mutual learning implicit in the STEM, all participants expanded each other's understandings of sustainability. Students were learning from instructors, instructors were learning from students, students were learning from students, instructors were learning from instructors, and all were learning and sharing knowledge with the greater community. As a result, all participants gained a deeper and broader understanding about human‐environment relationships and how humans impact natural resources.Practical implicationsBecause the assignments given to the university students were authentic performance tasks embedded in sustainability issues, students developed a broader disposition for thinking and learning and therefore become metacognitive. The STEM emphasized aesthetic education, integrating science and the arts. As a result, the participants developed their ability to connect academic domains of knowledge and creatively address sustainability challenges.Originality/valueThe convergence of science, art, and aesthetics enabled the participants to develop a deeper spiritual awareness and understanding of eco‐justice for the promotion of a sustainable society. The STEM utilized cultural resources of the university and New Britain community (i.e. institutional members of the NBMAA and The Central Connecticut State University). Students were introduced to the concept of mutual learning with all the communities and organizations involved.

Infusion of radiocontrast agents in vivo results in renal artery constriction and subsequent renal hypoperfusion. To examine the role of endothelin and of prostaglandins in radiocontrast-mediated renal vasoconstriction, rats were treated with an endothelin receptor antagonist, CP170687, and with indomethacin. The dose of CP170687 utilized was sufficient to reverse endothelin1-mediated constriction of isolated aortic rings and of renal blood flow in intact rats. In normal rats there was a transient drop in renal blood flow to 80% of baseline following sodium iothalamate injection, an effect which was not prevented by CP170687. In rats first given indomethacin, the drop in renal blood flow was more pronounced (to 63% of baseline) and was sustained. In this instance, CP170687 fully reversed the sustained decrease of renal perfusion. CP170687 also diminished the rise in systemic blood pressure seen following iothalamate injection. In the absence of indomethacin, iothalamate increased urinary prostaglandin E2 to a maximum of sevenfold above baseline values. In summary, injection of radiocontrast results in an immediate decrease in renal blood flow that is counteracted by an increase in renal prostaglandin formation. When prostaglandin synthesis is inhibited, prolonged endothelin-mediated renal vasoconstriction is observed that is reversed by an endothelin receptor antagonist.

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This study was designed to determine the incidence, etiology and consequences of severe hypermagnesemia. We retrospectively reviewed all hospital admissions over a 5-year period from 1984 to 1989 and identified 8 cases of severe hypermagnesemia (serum Mg ≧ 6.0 mg/dl) due to magnesium ingestion. All but 1 patient were elderly (mean age 70 ± 6 years). The etiology when identified was due to magnesium-containing cathartics (n = 3) or antacids (n = 3). The total amount of magnesium ingested was not excessive, but bowel disorders that may have enhanced absorption (such as active ulcer disease, gastritis, colitis, perforated viscus, massive gastric dilatation) were present in 7 of the 8 patients. Unexpectedly, only 1 had preexisting renal failure. Renal function was found to be normal in 1, only mildly to moderately impaired in 5 (creatinine < 3.6 mg/dl) and severely impaired in 2 (creatinine 7.6, 15.7 mg/dl). Clinical sequelae of hypermagnesemia were hypotension (n = 7), bradycardia (n = 2), respiratory depression (n = 3), EKG abnormalities (n = 6), depressed mental status (n = 5). Hypocalcemia (range 5.7-7.4 mg/dl) more severe than could be attributed to either hypoalbuminemia or acute renal failure was present in 7. A low anion gap (range -2 to 9) was present in 5. Most striking was the fact that despite clinical sequelae, the hypermagnesemia was unsuspected in 6 of the 8 cases. Hypermagnesemia can occur without severe renal insufficiency in association with bowel disease, particularly in elderly individuals, and may be a clinically unrecognized cause of cardiovascular dysfunction, hypocalcemia and neurologic or respiratory depression.

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