Modeled infiltration rate distributions for U.S. housing.

UNLABELLED: A set of 209 dwellings that represent 80% of U.S. housing stock is used to generate frequency distributions of residential infiltration rates. The set of homes is based on an analysis of the 1997 U.S. Department of Energy's Residential Energy Consumption Survey, which documents numerous housing characteristics including type, floor area, number of rooms, type of heating system, foundation type, and year of construction. The infiltration rate distributions are developed using the multizone network airflow model, CONTAM (CONTAMW 2.4 User Guide and Program Documentation, NISTIR 7251. National Institute of Standards and Technology.). In this work, 19 cities are selected to represent U.S. climatic conditions, and CONTAM simulations are performed for each of the 209 houses in these cities to calculate building air change rates for each hour over a year. Frequency distributions are then developed and presented nationally as well as based on house type and region. PRACTICAL IMPLICATIONS: These distributions will support indoor air quality, exposure, and energy analyses based on a truly representative collection of U.S. homes, which has previously not been possible. In addition, the methodology employed can be extended to other countries and other collections of buildings. For U.S.-specific analyses, these homes and their models, can be extended to include occupants, contaminant sources, and other building features to allow a wide range of studies to address other ventilation and indoor air quality issues.

Osteopathic medical education: the introduction of managed care principles into our undergraduate curriculum.

The authors review the strengths of traditional osteopathic medical education, identify the principles that managed care organizations have identified as being essential in preparing physicians to succeed in the current medical marketplace, and discuss the advantages of incorporating the best principles of managed care into osteopathic medical education. They present a strategy and outline proposed by the Department of Family Medicine at the Western University of Health Sciences College of Osteopathic Medicine of the Pacific for the integration of these principles into the undergraduate educational process.

Relationship between academic achievement and COMLEX-USA Level 1 performance: a multisite study.

The purpose of this study was to examine the relationship of performance on the Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) Level 1 with academic performance at colleges accredited by the American Osteopathic Association (AOA). Eighteen (95%) of 19 AOA-accredited colleges and 2146 students (91% of those taking the June 1999 examination) met criteria and participated. Students were classified by school representatives on the basis of academic performance in the first 2 years of the curriculum. The relationships of Level 1 performance with assigned classifications and grade point averages (GPAs) were studied. Of students classified in the highest 20% academically, the Level 1 pass rate was 100%, with a mean score of 599. Of students classified in the lowest 5%, the pass rate was 63.5%, with a mean of 416.3. For 16 schools that provided GPAs, the within-school correlations between Level 1 scores and GPAs ranged from r = 0.76 to r = 0.85, with a mean correlation of r = 0.79. School representatives were also asked to indicate, for each student, whether they expected the student to pass the examination. Pass rate for students in the "sure pass" category was 98.9%; "borderline," 82.5%; and "concerns," 61.5%. Academic performance in the first 2 years of osteopathic medical school was strongly associated with performance on COMPLEX-USA Level 1. The national pass rate for this examination was similar to those in previous years, and it remains unclear why school representatives overpredicted the number of failures. Further research is needed.

The planning, operation, and function of a clinical laboratory in a teaching hospital.

Shortly after World War I, laboratories began to grow in number and complexity in the hospitals throughout the United States. Need dictated the funding and therefore, expansion of these laboratories. In general, very little overall planning was introduced into the development of these laboratories but rather empiricism and reaction to pressure dictated the day-to-day, week-by-week development. Since a great deal of the teaching at that time was done on a one-by-one basis with laboratory learners, and since much of the laboratory work was done by physicians and used directly upon the patient, there was very little need for considering the laboratory as a more global resource for the teaching institution. As the science of medicine advanced and as the diversity and complexity of laboratory occupations increased, it was necessary to place more stress upon careful planning and operation of the clinical laboratory in the teaching institution. The laboratory was approached not only as a training area in its own right but as an adjunct to the undergraduate and postgraduate medical education occurring in the teaching institution. It became paramount then to consider the detail planning necessary to bring about a structural and functional entity that could respond to these more global teaching needs. It was imperative that the laboratory itself respond to its role and responsibility in the tripartite function of a teaching institution -- research, education, and service. In any good planning environment, effort must be expended towards setting goals and objectives; analytical methods applied to making assumptions and establishing premises. Alternate means for achieving goals and objectives were developed. Energy was expended in making forecasts and projecting results. Alternate means were sorted out and choices were made. Implementation guidelines were designed and an evaluation and feedback mechanism was instituted. In more recent years, we have attempted to apply these steps in planning to the development of laboratories and to the installation of operational procedures which would allow the clinical laboratory to truly function as a teaching unit and as a vital resource for the total training program of the institution in which it is housed.

Review of the monotreme fossil record and comparison of palaeontological and molecular data.

Monotremes have traditionally been considered a remnant group of mammals descended from archaic Mesozoic stock, surviving to the present day on the relatively isolated Australian continent. Challenges to this orthodoxy have been spurred by discoveries of 'advanced' Cretaceous monotremes (Steropodon galmani, Archer, M., et al., 1985. First Mesozoic mammal from Australia-an Early Cretaceous monotreme, Nature. 318, 363-366) as well as by results from molecular data linking monotremes to therian mammals (specifically to marsupials in some studies). This paper reviews the monotreme fossil record and briefly discusses significant new information from additional Cretaceous Australian material. Mesozoic monotremes (including S. galmani) were a diverse group as evidenced by new material from the Early Cretaceous of New South Wales and Victoria currently under study. Although most of these new finds are edentulous jaws (limiting dental comparisons and determination of dietary niches), a range of sizes and forms has been determined. Some of these Cretaceous jaws exhibit archaic features-in particular evidence for the presence of a splenial bone in S. galmani-not seen in therian mammals or in post-Mesozoic (Tertiary and Quaternary) monotreme taxa. Tertiary monotremes were either archaic ornithorhynchids (toothed platypuses in the genera Monotrematum and Obdurodon) or tachyglossids (large echidnas in the genera Megalibgwilia and Zaglossus). Quaternary ornithorhynchid material is referable to the sole living platypus species Ornithorhynchus anatinus. Quaternary echidnas, however, were moderately diverse and several forms are known (Megalibgwilia species; 'Zaglossus' hacketti; Zaglossus species and Tachyglossus aculeatus).

New information about the skull and dentary of the Miocene platypus Obdurodon dicksoni, and a discussion of ornithorhynchid relationships.

A reconstruction of the skull, dentary and dentition of the middle Miocene ornithorhynchid Obdurodon dicksoni has been made possible by acquisition of nearly complete cranial and dental material. Access to new anatomical work on the living platypus, Ornithorhynchus anatinus, and the present comparative study of the cranial foramina of Ob. dicksoni and Or. anatinus have provided new insights into the evolution of the ornithorhynchid skull. The hypertrophied bill in Ob. dicksoni is seen here as possibly apomorphic, although evidence from ontogenetic studies of Or. anatinus suggests that the basic form of the bill in Ob. dicksoni (where the rostral crura meet at the midline) may be ancestral to the form of the bill in Or. anatinus (where the rostral crura meet at the midline in the embryonic platypus but diverge in the adult). Differences in the relative positions of cranial structures, and in the relationships of certain cranial foramina, indicate that the cranium may have become secondarily shortened in Or. anatinus, possibly evolving from a more elongate skull type such as that of Ob. dicksoni. The plesiomorphic dentary of Ob. dicksoni, with well-developed coronoid and angular processes, contrasts with the dentary of Or. anatinus, in which the processes are almost vestigial, as well as with the dentary of the late Oligocene, congeneric Ob. insignis, in which the angular process appears to be reduced (the coronoid process is missing). In this regard the dentary of Ob. insignis seems to be morphologically closer to Or. anatinus than is the dentary of the younger Ob. dicksoni. Phylogenetic conclusions differ from previous analyses in viewing the northern Australian Ob. dicksoni as possibly derived in possessing a hypertrophied bill and dorsoventrally flattened skull and dentary, perhaps being a specialized branch of the Obdurodon line rather than ancestral to species of Ornithorhynchus. The presence of functional teeth and the robust, flattened skull and dentary in Ob. dicksoni argue for differences in diet and lifestyle between this extinct ornithorhynchid and the living Ornithorhynchus.