OBJECTIVES To evaluate the clinical severity and proportionality of small for gestational age, very low birth weight neonates (< 1,500 g) and to estimate the neonatal mortality risk associated with the condition of being small for gestational age according to the degree of severity and proportionality. METHODS Observational design. All of the NEOCOSUR Collaborative Group's very low birth weig...

In this paper, we sought to document household income volatility as experienced by children over time, as one understudied aspect of household economic circumstances that might contribute to observed socioeconomic differences in children’s achievement. Our analysis of six panels of the nationally representative Survey of Income and Program Participation (SIPP) across a 25-year period reveal tha...

In large sample studies where distributions may be skewed and not readily transformed to symmetry, it may be of greater interest to compare different distributions in terms of percentiles rather than means. For example, it may be more informative to compare two or more populations with respect to their within population distributions by testing the hypothesis that their corresponding respective...

Polydisperse glass microsphere standards were analysed by 25 international teams of particle metrology specialists using unambiguous methods such as microscopy, sedimentation, electroformed sieving and Coulter counting. The nominal size distributions were: 1-10, 3-30, 10-100 and 50-350 microns (m). The Laser Diffraction Proficiency Testing Scheme (LDPTS) then sent the samples to about 65 parti...

A study was carried out in which activity of gamma-glutamyl transpeptidase was measured in 259 samples of amniotic fluid obtained at various weeks of pregnancy. Two hundred and twenty-eight of the babies subsequently delivered had no chromosome abnormality and served as controls, while in 31 various chromosome abnormalities were detected. Mean activity of gamma-glutamyl transpeptidase in the co...

OBJECTIVE To estimate whether the severity of uterine anomaly is associated with the risk of adverse pregnancy outcomes. METHODS Retrospective cohort study of patients delivered by one maternal fetal medicine group from 2005 to 2012. We included 158 patients with a singleton pregnancy and a uterine anomaly, as well as an equal number of randomly selected unexposed singleton pregnancies delive...

This paper studies incumbent price response to entry by low-cost carriers in the U.S. airline industry. I find that legacy carrier incumbents decrease their mean airfare, 10th percentile airfare, and 90th percentile airfare following entry by a low-cost carrier. Airfares decrease by a larger percentage at the right tail of the incumbents’ price distribution than at the left tail, suggesting tha...

Physicians play a critical role in determining medical-care expenditures. In this study, we empirically assess the degree to which physicians exploit their bargaining leverage over insurance carriers as a means to raise service prices. We also examine the degree to which these potentially higher payments may translate into different levels of service utilization. We find that physicians are abl...

Uncritical application of standard weight percentile charts, derived from white infants, to infants from different ethnic groups may result in an overestimate of the incidence of intrauterine growth retardation in those groups. The ratio of mid-arm circumference to occipitofrontal circumference was studied in 194 babies (49 Asian, 58 black, and 87 white). In contrast with birth weight the ratio...

OBJECTIVE To study whether infant weight for gestational age, and gestational age predict mother- and father-rated infant temperament (IBQ) at 6 months. METHODS The sample comprised of family units with both biological parents and infants born at term (n = 152). Data on weight and gestational age were collected form obstetric database. RESULTS Infants born small for gestational age (SGA) (w...