Antioxidant contents of bell pepper and melon fruits grown in soil amended with recycled waste

Composting and land application of municipal sewage sludge (SS) and yard waste (YW) compost are increasingly popular ways for using organic waste as a source of organic matter, while decreasing the amount of waste being diverted into landfills. Researchers have largely ignored the effect of SS and SS mixed with YW (SS+YW) compost on the antioxidant contents of vegetables grown under this practice. Accordingly, the main objective of this investigation was to monitor the impact of SS and SS+YW on the nutritional composition of pepper and melon fruits at harvest. Total phenols and ascorbic acid contents of pepper and melons (determined by the Folin-Ciocalteau and the dichlorophenol–indophenol methods, respectively) were greater in pepper than melon fruits. Soil amended with SS or SS+YW significantly elevated the concentrations of ascorbic acid and total phenols in melon fruits compared to no-mulch native soil. The application of SS did not modify the concentration of β-carotene in melon fruits at three harvests. Regardless of soil treatments, ascorbic acid and total phenols concentrations were greater in melon fruits collected at the first harvest compared to harvest three. Pepper fruits collected at harvest three contained the greatest concentrations of ascorbic acid and total phenols; whereas, pepper fruits collected at the second harvest contained the greatest concentrations of soluble sugars.     

Total Factor Productivity Change in the New England Groundfish Fishery: 1964–1993

We develop estimates of total factor productivity (TFP) change in the New England groundfish fishery from 1964 to 1993, using a procedure similar to Squires' (1992, Rand J. Econom.23(2), 221–236) method, which extends standard TFP measurement by including the effect of fluctuations in stock abundance. The results indicate that TFP increased on average by 4.4% per year from 1964 to 1993. A higher average rate of increase occurred between 1964 and 1982, possibly due to new technologies (e.g., fishfinders). TFP declined at 0.33% annually from 1983 to 1993 due to stringent output and effort control measures.     

First-trimester diagnosis of conjoined twins

Conjoined twins are a rare and complex complication of monozygotic twinning, which is associated with high perinatal mortality. Early prenatal diagnosis of conjoined twins allows better counselling of the parents regarding the management options, including continuation of pregnancy with post-natal surgery, termination of pregnancy or selective fetocide in case of a triplet pregnancy. With the introduction of high-resolution and transvaginal ultrasound imaging, accurate prenatal diagnosis of conjoined twins is possible early in pregnancy. We have reviewed the medical literature on the early prenatal diagnosis of suspected conjoined twins using a MEDLINE search. Although first-trimester diagnosis of conjoined twins is feasible, false-positive cases are common before 10 weeks because, earlier in gestation, fetal movements are limited and monoamniotic twins may appear conjoined. As most parents opt for immediate termination of pregnancy at confirmation of the diagnosis, there are limited data on the prenatal follow-up of conjoined twins. When the parents opt for conservative management, half of the fetuses die in utero and another 44% will die during the neonatal period. A detailed analysis of case reports where 3D imaging was used indicates that this modality does not improve on the diagnosis made by 2D ultrasound. Overall, very early prenatal diagnosis and first-trimester 3D imaging provide very little additional practical medical information compared to the 11–14 weeks' ultrasound examination. Copyright © 2005 John Wiley & Sons, Ltd.     

Effects of Habitat Loss and Fragmentation on the Behavior and Demography of Gray-Tailed Voles

We monitored the short term behavioral and demographic responses of gray-tailed voles (Microtus canicaudus) to the reduction and fragmentation of their habitat. Our objectives were (1) to test whether animals perished or moved into remaining fragments after 70% of their habitat was removed; and (2) to test the null hypothesis that the social structure and demography of animals would not differ between habitats consisting of one large continuous fragment (625 m²), a mosaic of 25 small fragments (each 25 m²) separated by 4 m of bare ground, and control, unmanipulated habitats (1850 m²). We conducted the experiment in 12, 0.2-ha enclosures planted with alfalfa with four replicates for each of two manipulated treatments and a control. A 70% reduction in habitat did not adversely affect adult survival, reproductive rate, juvenile recruitment, or population size. However, an influx of unrelated females into habitat fragments resulted in decreased juvenile recruitment in those fragments. Voles from cleared habitat moved into the remaining habitat and did not measurably affect the resident population. Similarly, the demography of voles did not differ significantly among the large-fragment, small-fragment, and control enclosures. Peak density estimates based on the amount of habitat in each enclosure were 545 animals per hectare in control, 1056 in large-fragment, and 2880 in small-fragment enclosures. Reduced movement of animals among the small fragments was the most obvious effect of habitat fragmentation. Six percent of females and 15% of males moved among small fragments within a week compared to approximately 60% moving comparable distances in large-fragment and control enclosures. Rates of juvenile dispersal and sexual maturation declined throughout the summer on all treatments, were associated with season and density, and were only marginally associated with habitat loss and fragmentation. We conclude that at the time of habitat removal and fragmentation, populations were small enough to accommodate a 70% reduction in habitat and still continue to increase in numbers. The social system of gray-tailed voles was sufficiently flexible to accommodate an influx of animals to withstand densities> 1000 voles per ha. The behavioral and demographic features of gray-tailed voles are similar to those reported for other small mammals, thus confirming the use of voles for ecological model systems in habitat fragmentation studies.     

Impact of Channelization on Oyster Production: A Hydrodynamic-Oyster Population Model for Galveston Bay, Texas

A hydrodynamic-oyster population dynamics model was developed to assess the effect of a change in ship channel configuration under different freshwater inflow regimes and different future hydrologies on oyster (Crassostrea virginica) populations in Galveston Bay, Texas. The population dynamics model includes the effects of environmental conditions, predators, and the oyster parasite Perkinsus marinus on oyster populations. The hydrodynamic model includes the effects of wind stress, river runoff, tides, and oceanic exchange on the circulation of the Bay. Simulations were run for low, mean, and high freshwater inflow conditions under the present (1993) hydrology and predicted hydrologies for 2024 and 2049 that include anticipated water diversion projects to satisfy the freshwater demands of population growth in metropolitan Houston, Texas. Simulation results show that oyster biomass was predicted to increase after enlargement of the ship channel. Oyster biomass is expected to increase on about 53% of total reef acreage when averaged over a 50-yr time span. Oyster reef acreage characterized by increased biomass after channel enlargement increases moderately under the present hydrology and the 2049 hydrology, but decreases slightly in 2024. Lower biomass in 2024 is due to reduced freshwater inflow and increased saltwater intrusion that pushes the optimal areas for oyster growth somewhat farther upbay than in 2049. Declines in oyster biomass, noted in most simulations in downbay reaches, were more than balanced by increased oyster biomass upbay. The differential between upbay and downbay reefs can be explained by an increase in mortality from Perkinsus marinus downbay and saltwater intrusion upbay that expands the area characterized by moderate salinities. The 20th century history of Galveston Bay is one of expansion of isohaline structure and increased oyster production as a result of anthropogenic modification of bay physiography. The salinity gradient of the 1990s, however, is not in equilibrium with the distribution of hard substrate required for oyster growth, that reflects an earlier equilibrium with the pre-1900s hydrodynamics. Increased saltwater intrusion is normally disadvantageous to oyster populations; but, in this case, channel enlargement further expands the salinity gradient upbay and outward (east and west) from the channel. As a result, in most years, oyster biomass is increased because moderate salinities cover more of the pre-1900s reef tracts where hard substrate is plentiful.     

Progress in teenage crash risk during the last decade

OBJECTIVE: The purpose of the present study was to examine the most recent data on teenagers' fatal and nonfatal crashes in the United States to determine current crash rates as well as changes in crash rates during the past decade METHODS: Data for calendar years 1996 and 2005 were extracted for fatal crashes from the Fatality Analysis Reporting System and for police-reported crashes from the National Automotive Sampling System/General Estimates System. To calculate crash rates, population data were obtained from the Census Bureau, and mileage data were obtained from the 2001 National Household Travel Survey RESULTS: During 2001-02, the latest year for which mileage data are available, 16 year-old drivers had higher fatal and nonfatal crash rates per mile traveled than all but the very oldest drivers. However, fewer 16 year-olds typically are licensed to drive and they drive fewer miles per year than all but the oldest drivers. Thus, their fatal and nonfatal crash rates per population in 2005 were lower than among other teenagers and among drivers 20-29. During the past decade the most progress has been made in reducing crashes among the youngest drivers. Between 1996 and 2005 both fatal and police-reported crashes per population declined about 40% for 16 year-old drivers, compared with about 25% for 17 year-old drivers and 15-19% for 18 year-old drivers. The greatest reductions for 16 year-olds occurred in nighttime crashes, alcohol-related fatal crashes, and fatal crashes involving multiple teenage passengers. CONCLUSIONS: Substantial progress has been made in reducing fatal and nonfatal crashes per population among 16 year-old drivers. Although this study was not designed to examine the role of graduated licensing, the results are consistent with the increased presence of such laws, many of which restrict nighttime driving and driving with teenage passengers. IMPACT ON INDUSTRY: Restrictions on nighttime driving and driving with teenage passengers should be made a part of all states' graduated licensing systems. Historically, 16 year-olds have had the highest crash risk per licensed driver and per mile traveled. Given the dramatic reductions in per population crash rates among 16 year-olds, it is possible that their per mile and per licensed driver rates also have declined and may no longer be as elevated relative to other ages. However, shortcomings in the licensed driver data and a lack of recent mileage data hamper our ability to examine these issues. If we are to continue to provide a yardstick against which we can measure progress among the youngest drivers, immediate steps need to be taken to restore the availability of reliable exposure data.