Modeling radium and radon transport through soil and vegetation

A one-dimensional flow and transport model was developed to describe the movement of two fluid phases, gas and water, within a porous medium and the transport of 226Ra and 222Rn within and between these two phases. Included in this model is the vegetative uptake of water and aqueous 226Ra and 222Rn that can be extracted from the soil via the transpiration stream. The mathematical model is formulated through a set of phase balance equations and a set of species balance equations. Mass exchange, sink terms and the dependence of physical properties upon phase composition couple the two sets of equations. Numerical solution of each set, with iteration between the sets, is carried out leading to a set-iterative compositional model. The Petrov-Galerkin finite element approach is used to allow for upstream weighting if required for a given simulation. Mass lumping improves solution convergence and stability behavior. The resulting numerical model was applied to four problems and was found to produce accurate, mass conservative solutions when compared to published experimental and numerical results and theoretical column experiments. Preliminary results suggest that the model can be used as an investigative tool to determine the feasibility of phytoremediating radium and radon-contaminated soil.     

Development of the gooseneck barnacle Pollicipes polymerus (Cirripedia: Lepadomorpha): Fertilization through settlement

Pollicipes polymerus (Sowerby, 1833) is a common barnacle in rocky intertidal zones of the West Coast of North America whose development has been previously undescribed in detail. In the present study, certain aspects of the development of P. polymerus are recorded from fertilization through settlement. In vitro fertilization has been accomplished using already-implanted sperm plus ovulating eggs and oviducal gland fluid. The eggs are small (about 100 μ diameter at fertilization; 90 x 140 μ at first cleavage) and somewhat yolky. Embryos obtained from brooding adults and from in vitro fertilization were reared in glass dishes until hatching. Cleavage was total, asynchronous and unequal. Division of the D macromere lagged behind division of the other blastomeres, and gastrulation occurred by epiboly so that blastoderm surrounded the macromeres. The nauplii hatched an average of 25.4 days (range was 20.3 to 30.1 days) after fertilization, and molted within 1 day to Stage II nauplii. From Stages II through VI the nauplii required food. As they grew from stage to stage, the number of setae per appendage increased. Nauplii have feathery and hispid-type setae, previously described only in Chthamalus aestuarii. In contrast to other pedunculate larvae which have been described, P. polymerus nauplii are small and have specialized feathery setae. Cypris-larva settlement was stimulated only when healthy adult peduncles were available, thus showing an affinity for its own species.     

Shell choice in<Emphasis Type="Italic"> Pagurus longicarpus</Emphasis> hermit crabs: does predation threat influence shell selection behavior?

Pagurus longicarpus hermit crabs depend on empty gastropod shells for protection against predation. Hermit crabs avoid gastropod shells in which holes have been drilled by naticid gastropods, and hermit crabs forced to occupy drilled shells are more vulnerable to predation by green crabs, Carcinus maenas. In this study, we examined the effect of predator cues on P. longicarpus shell investigation behavior and shell choice. In paired laboratory shell choice trials, we examined hermit crab response to green crab chemical cues. We compared hermit crabs from two sites differing in the percentage of Littorina littorea shells with drill holes. The percentage of time hermit crabs spent occupying intact shells increased significantly in the presence of predator cues. The effect of predator cues on the amount of time hermit crabs spent investigating shells differed between individuals from the two sites. Predator effluent had a marginal effect on the proportion of hermit crabs initially choosing intact shells and within 15 min most hermit crabs in both treatments occupied intact shells due to shell switching. These results indicate that predation cues alter P. longicarpus shell choice behavior favoring intact shells, which provide greater protection. In summary, predation appears to be a key factor influencing hermit crab shell selection behavior.Communicated by T. Czeschlik     

The ability of conditioned Microplitis croceipes (Hymenoptera: Braconidae) to distinguish between odors of aflatoxigenic and non-aflatoxigenic fungal strains

Summary. The parasitic wasp Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) learns to associate odors with food resources and subsequently exhibits a characteristic food-seeking behavior when encountering the learned odor. Wasps so conditioned, learned and subsequently demonstrated an ability to distinguish among aflatoxigenic and non-aflatoxigenic Aspergillus flavus and A. parasiticus strains. The effects of fungal species, strain, age (5, 10-12, 20, and 30 d) and growth media (potato dextrose agar, peanut agar and corn agar) on the learning and recognition responses of the conditioned wasps were examined. The level of differentiation between fungal strains by conditioned wasps was lowest when working with 5-d-old fungal cultures but increased with age and generally peaked with 20-d-old fungi. Wasps responded generally stronger to the fungal strain conditioned to independent of growth media. This ability of parasitic wasps to learn and distinguish fungal odors can open new avenues in insect learning.     

Lifetime reproductive success in the spotted sandpiper (Actitis macularia) : sex differences and variance components

Summary Lifetime reproductive success (LRS) of male (N=103) and female (N= 66) spotted sandpipers (Actitis macularia) was studied for 13 years of a 17-year study at Little Pelican Island, Leech Lake, Minnesota. There was no sex difference in longevity, but females had significantly more mates, eggs, chicks, fledged young, and young returning in subsequent years than did males. Variance in LRS was partitioned into five life-history components: longevity (L), mates per year (M), eggs per mate (E), proportion eggs hatched (H), and proportion of chicks fledged (F). For both sexes, F accounted for the greatest proportion of variance in LRS (males, 43%; females, 47%), followed by L (males, 26%; females, 43%) and H (males, 21%; females, 28%). Positive covariance between H and F was consistent with predator-caused clutch and brood loss. Contrary to our expectations, males had a higher coefficient of variation in reproductive success than did females. This was because males were relatively more likely than females to produce no young.Offprint requests to: L.W. Oring at the current address     

Conjoined twins

Conjoined twins have been a source of fascination for both the general public and the medical profession since time immemorial. Their birth was initially viewed as an ominous sign of impending disaster. This was followed by a prolonged period through the Middle Ages and into the nineteenth century when they were regarded as freaks or monstrosities and were exhibited with substantial financial reward at circuses and sideshows. Recently, conjoined twins have attracted intense media interest, which has coincided with increasing success in their separation. This article gives an overview of the role of prenatal ultrasound in assessing the prognosis and discusses the post-natal surgical management and outcome. Copyright © 2005 John Wiley & Sons, Ltd.     

The effects of graduated driver licensing on hospitalization rates and charges for 16-and 17-year-olds in North Carolina

OBJECTIVE: To mitigate the high risk of motor vehicle crashes for young beginning drivers, over 40 states and the District of Columbia have implemented graduated driver licensing (GDL) systems that gradually and systematically ease teen drivers into higher risk driving conditions. Evaluations of GDL programs using motor vehicle crash data have demonstrated marked declines in crashes. The objective of this study is to examine the association between the implementation of the North Carolina GDL program and the rate of hospitalization, as well as hospital charges, for 16-and 17-year-old drivers. METHODS: Data were obtained from the North Carolina Hospital Discharge Database for the 26 months before and 46 months after the December 1, 1997, implementation of the GDL program. ARIMA interrupted time series analyses were used to model monthly hospitalization rates, controlling for the hospitalization rates of 25-to 54-year-old drivers. ARIMA analyses were also used to determine whether changes occurred in monthly total hospital charges. RESULTS: Among the 568 16-year-old hospitalized drivers, GDL was associated with a 36.5% decline in the hospitalization rate per population and a 31.2% decline in the total monthly driver hospitalization charges. Although a 12% reduction in the rate of hospitalizations was observed among the 615 17-year-old drivers, the analysis lacked sufficient power to be statistically reliable. No consistent change was observed in the 16-year-old driver total monthly hospital charges. CONCLUSIONS: The North Carolina GDL program was associated with a marked decline in the rate of hospitalizations and hospital charges for 16-year-old drivers. Following the implementation of GDL, over $650,000 in hospital charges have been averted each year for 16-year-old drivers. Analyses suggest these reductions were primarily the result of reduced exposure rather than an improvement in teen driving.     

APCA Is Thriving

Fiscal nineteen seventy three-four was another busy year for the Association. It was a year of expanded services, publications, and meetings. New initiatives on the part of the Board of Directors, the Technical Council and its committees, local APCA Sections and the Headquarters staff were undertaken. All of the statistical reports are positive, and show increased membership, pages published, advertising, meetings, and involvement of members. But of more importance, APCA is filling its role in a positive and meaningful way, and is continuing to attract persons working in the air pollution control profession to its many programs.

As most of you know by now, dues for individual members have been increased from $25 to $35 annually because of the continued inflation in postage, paper, and cost of doing business.