Observations related to chronologic and gynecologic age in pregnant adolescents.

A low chronologic age (less than or equal to 15 years) and low gynecologic age (less than or equal to 2 years) have been considered factors that increase medical complications among adolescent pregnant women. Gynecologic age (GA) is defined in this study as age in years at conception minus age at menarche. Two hundred twelve consecutive pregnant teenagers were followed prospectively in the Teen OB Clinic at the University of California, San Diego Medical Center, between August 1978 and July 1981. The clinic population consisted of 37.3 percent Whites, 35.8 percent Hispanics, 20.8 percent Blacks, and 6.1 percent other (mostly Indochinese). Sixty-eight percent of the patients were funded by MediCal. The patient population was divided by chronological age (CA) at conception into those 15 years or less or 16 years or older. A low chronological age was found to be a significant risk factor for premature rupture of membranes. Teenagers with a low gynecologic age (less than or equal to 2) had a lower mean pre-pregnancy weight and body mass index (Kg/M2) than teenagers with a higher gynecologic age. In this study, we did not find that a low CA or GA was correlated with a higher frequency of pregnancy-induced hypertension, prenatal medical problems, obstetrical problems at labor or delivery, or an excessive number of low-birthweight infants

Global trends in exposure to light pollution in natural terrestrial ecosystems

This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.The rapid growth in electric light usage across the globe has led to increasing presence of artificial light in natural and semi-natural ecosystems at night. This occurs both due to direct illumination and skyglow - scattered light in the atmosphere. There is increasing concern about the effects of artificial light on biological processes, biodiversity and the functioning of ecosystems. We combine intercalibrated Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) images of stable night-time lights for the period 1992 to 2012 with a remotely sensed landcover product (GLC2000) to assess recent changes in exposure to artificial light at night in 43 global ecosystem types. We find that Mediterranean-climate ecosystems have experienced the greatest increases in exposure, followed by temperate ecosystems. Boreal, Arctic and montane systems experienced the lowest increases. In tropical and subtropical regions, the greatest increases are in mangroves and subtropical needleleaf and mixed forests, and in arid regions increases are mainly in forest and agricultural areas. The global ecosystems experiencing the greatest increase in exposure to artificial light are already localized and fragmented, and often of particular conservation importance due to high levels of diversity, endemism and rarity. Night time remote sensing can play a key role in identifying the extent to which natural ecosystems are exposed to light pollution.European Research Council/ European Union’s Seventh Framework Programme (FP7/2007–2013