No abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Biometrika Trust is collaborating with JSTOR to digitize, preserve and extend access to Biometrika. SUMMARY Methods are given for summarizing and comparing the orientations of samples of orientable objects. It is assumed each orientation is characterized by p distinguishable directions in n-space with fixed angles between them. The probability distribution used for the orientations is closely related to the multinormal distribution: this is used for approximating some orientational sampling distributions. The methodology is illustrated with data from the clinical vectorcardiogram.

Air pollution episodes in northern New England often are caused by transport of pollutants over water. Two such episodes in the summer of 2002 are examined (22–23 July and 11–14 August). In both cases, the pollutants that affected coastal New Hampshire and coastal southwest Maine were transported over coastal waters in stable layers at the surface. These layers were at least intermittently turbulent but retained their chemical constituents. The lack of deposition or deep vertical mixing on the overwater trajectories allowed pollutant concentrations to remain strong. The polluted plumes came directly from the Boston, Massachusetts, area. In the 22–23 July case, the trajectories were relatively straight and dominated by synoptic-scale effects, transporting pollution to the Maine coast. On 11–14 August, sea breezes brought polluted air from the coastal waters inland into New Hampshire.

Several studies of styrene-butadiene rubber (SBR) workers have reported excess cancers at various sites; however, little could be concluded concerning specific etiologic agents because of the multiple exposures encountered by these groups. The current study examined cause-specific mortality in a cohort of 2,586 male workers employed for at least 6 months between 1943 and 1979 in a butadiene manufacturing plant that supplied butadiene to two SBR plants. Standardized mortality ratios were calculated using national (NSMR) and local (LSMR) comparison populations. The all-cause NSMR was 80 (p less than 0.05) and the all-cancer NSMR was 84; the corresponding LSMRs were 96 and 76 (p less than 0.05). No significant excesses were observed for any cause of death except lymphosarcoma and reticulum cell sarcoma (NSMR = 235). When the cohort was subdivided into routine, nonroutine, and low-exposure groups, the SMRs were consistently elevated for this cause of death in all three groups. However, direct comparisons between each of the two exposure groups and the low-exposure group were inconsistent. This suggests butadiene may not be responsible for the excess, but the association deserves close attention in future studies.

ExtractUsing the total body plethysmograph, a method for the measurement of lung volume and airway resistance was developed for infants and young children of 1 month-5 years of age. The subjects were studied in a supine position using a reproducible method of sedation. The procedure providing the most consistent results involved use of a Rendell-Baker mask directly controlled by the operator while the subjects were breathing through the nose. Availability of an oscilloscope permitted immediate detection of pressure leaks, artifacts, and abnormal patterns during each determination and minimized potential errors during the study of each subject. Care was required to avoid pressure on the tip of the nose because an abnormally high airway resistance resulted.The logarithmic relation of thoracic gas volume (TGV) at functional residual capacity (FRC) to body length for 52 normal subjects compared well with results obtained on newborn infants and with those obtained on older subjects. The equation was: TGV at FRC, liters = 1.57 x 10-5 x length, cm 2.238 (correlation coefficient = 0.948). The logarithmic relation of airway conductance to TGV was: conductance, liters/sec/cm H,O = 0.1431 TGV, liters 0 . 6441 (correlation coefficient = 0.835). Comparison with older subjects was limited by the difference in airflow rates at which the airway conductance was determined (0.06-0.28 literslsec versus about 0.5 literslsec for adults) and by the use of sedation and nasal breathing in this study; adults are studied awake and during mouth breathing. Comparison of our conductance values with those obtained on unsedated newborns suggests that either sedation alters the airway resistance or that some change occurs in the airway size-lung volume relation during the first weeks of life.Examples of the application of this method to patients with asthmatic bronchitis and cystic fibrosis of the pancreas are provided. SpeculationIt is possible that an airflow-lung volume-airway resistance relation exists throughout life; however, the results presented in this study, combined with those previously presented on newborns for airway resistance, suggest that a change may occur in the relation of the size of the airways to lung volume during early infancy, or that sedation alters airway resistance. Development of this and other methodology should permit more adequate studies of the early changes in pulmonary physiology associated with growth and the acute and chronic pulmonary conditions seen during the first 5 years of life. DOERSHUK, DOWNS, MATTHEWS and LOUGH