Ozone concentration patterns observed during the 1976–1977 long-range transport study

The ozone distribution observed for April to September, 1976 and 1977, have been categorized and analyzed according to episodes. The major characteristics of the 40 ozone episodes are discussed. The major features are: (1) most episodes were associated with high pressure systems that enter the United States of America through Minnesota, (2) they normally have a duration which averages seven days for both years, (3) transported ozone from the midwest affected the northeastern United States and (4) the highest ozone concentrations were usually found in Connecticut. A particular episode, 9–19 May 1977, is examined in detail and shows the production of ozone in the midwestern United States under stagnant conditions and its eventual eastward transport. The first two days of the subsequent episode are shown to demonstrate the local accumulation of ozone in the northeast. The distribution of ozone throughout the entire eastern half of the country is also illustrated.     

Driving performance comparing older versus younger drivers

Objectives: A cross-sectional study was conducted at the Touro University California campus to compare differences in reaction times and driving performance of younger adult drivers (18–40 years) and older adult drivers (60 years and older). Each test group consisted of 38 participants.

Methods: A Simple Visual Reaction Test (SVRT) tool was used to measure reaction times. The STISIM Drive M100 driving simulator was used to assess driving parameters. Driving performance parameters included mean lane position, standard deviation of mean lane position measured, mean speed, standard deviation of mean speed, car-following delay, car-following modulus, car-following coherence, off-road accidents, collisions, pedestrians hit, and traffic light tickets.

Results: Compared to younger participants, older drivers experienced significantly slower reaction times (510.0 ± 208.8 vs. 372.4 ± 96.1 ms, P =.0004), had more collisions (0.18 ± 0.39 vs. none, P =.0044), drove slower (44.6 ± 6.6 vs. 54.9 ± 11.7 mph, P <.0001), deviated less in speed (12.6 ± 4.3 vs. 16.8 ± 6.3, P =.0011), and were less able to maintain a constant distance behind a pace car (0.42 ± 0.23 vs. 0.59 ± 0.24; P =.0025).

Conclusions: Differences exist in driving patterns of older and younger drivers as measured by reaction times and driving simulator outcomes. These results are the first to compare these 2 specific adult age groups' driving performance as measured by a standardized driving simulator scenario. Identifying these differences is essential in addressing them and preventing future traffic injuries.     

Investigation of heavy metal accumulation in Polygonum thunbergii for phytoextraction

In this study, cadmium (II), lead (II), copper (II) and zinc (II) were determined in Polygonum thunbergii and soil from the Mankyung River watershed, Korea. Soil samples contained detectable lead (<17.5 g g(-1)), copper (<8.4 g g(-1)) and zinc (<24.5 g g(-1)), whereas cadmium was undetectable. Whole plants of P. thunbergii contained detectable lead (<320.8 g g(-1)), copper (<863.2 g g(-1)) and zinc (<2427.3 g g(-1)), whereas cadmium was detectable only in the stem (<7.4 g g(-1)) and root (<10.1 g g(-1)). Whole plant concentrations were very different for each metal, particularly in the case of zinc. The mean content of heavy metal in the whole plants increased in the order of cadmium (8.5 g g(-1))相似文献   

Ladybird mothers mitigate offspring starvation risk by laying trophic eggs

A large proportion of ladybird beetle (Coleoptera: Coccinellidae) eggs are apparently infertile—they do not develop an embryo and are consumed by larvae hatching within the egg batch. The predicted benefits of egg consumption for larvae are empirically well supported. An important question, however, remains: are these eggs a maternal strategy to feed offspring (i.e., trophic eggs) or did egg eating evolve to exploit unavoidably infertile eggs? We investigated the adaptive value of infertile eggs in laboratory experiments with multicoloured Asian ladybirds (Harmonia axyridis). Female H. axyridis were assigned to low and high resource environments for brief intervals; we predicted that tactics to facilitate egg cannibalism, such as infertile egg production and hatching asynchrony, would be adopted in low food environments in which starvation risk for offspring is greater. We conducted two experiments in this manner that provided females with information about resource levels through prey feeding or scent. We also observed female oviposition patterns and tested for infertile egg distributions that departed from random. Females produced 56% more infertile eggs in the low vs. the high food treatment; however, hatching synchrony did not change. We consider a potential confound between information and nutrition state unlikely because ladybirds are well able to tolerate low food for 24 h, the duration of trials, and because females were in good condition when trials began. Results suggest that ladybirds use information from prey encounter to manipulate the proportion of trophic eggs in a manner consistent with the adaptive hypothesis, the first evidence of trophic egg plasticity in a non-eusocial insect.     

Air quality impact assessment

Air quality impact assessment (AQIA) is an important technique for determining the relative contribution to ground level pollutant concentrations of specific current or future source emissions at receptor sites. The principal activities in AQIA are air quality modelling and monitoring techniques. The choice of techniques which are applicable to a particular situation is intimately related to the problem to be assessed. A review of relevant modelling techniques has been presented, with emphasis placed on Gaussian plume models because of their ease of use and broad applicability. Alternative modelling techniques have been suggested when departures from the Gaussian form in the atmosphere occurs or when more detailed information on atmospheric chemistry, deposition or long range transport is required. The objectives and techniques of ambient air quality monitoring have been examined and the siting of instruments, duration and frequency of sampling, choice of monitoring rationale (fixed or mobile), minimization of sampling errors, data storage and analysis are discussed. Modelling and monitoring are essential to successful AQIA. An orderly approach to the principles and procedures involved in performing AQIA studies, using these two techniques in conjunction, has been presented.     

Development of a Provisional Physical Habitat Index for Maryland Freshwater Streams

Provisional physical habitat indices were developed and validatedfor Maryland Coastal and Non-Coastal Plain streams using variables (commonly called metrics) that best discriminated reference and degraded conditions based on biological, chemicaland land use data from the 1994–97 Maryland Biological Stream Survey (MBSS). These habitat indices contained variables that described structural, hydrological, vegetative and aesthetic components of stream habitat. Variables with the best discriminatory power for Coastal Plain streams were: instream habitat, velocity/depth diversity, pool/glide/eddy quality, embeddedness, maximum depth and aesthetic rating. Physical habitat variables with the best discriminatory power for Non-Coastal Plain sites were: instream habitat, velocity/depth diversity, riffle/run quality, embeddedness, number of rootwads and aesthetic rating. The overall classification efficiency forindex validation was 76% for both indices pooled over both strata. Scaled physical habitat index values (0–100) for bothstrata identified nearly twice as many good sites (31%) as very poor sites (16%). More than half the Maryland sites werein the poor to fair range (53%).     

DNA fingerprints of orange roughy,Hoplostethus atlanticus: a population comparison

Genetic variability among Hoplostethus atlanticus collected from two spawning grounds east and west of New Zealand was examined using DNA fingerprints as revealed by hybridization with three clonal probes: 33.15, M13 and 3HVR. The 33.15 and 3HVR fingerprints revealed a complex pattern of restriction fragments, apparently refecting a multi-locus system of highly variable minisatellite alleles similar to the pattern of alleles reported in other vertebrates. The M13 fingerprints revealed a distinct pattern of restriction fragments of high molecular weight, reflecting a single-locus system that overlapped with the family of minisatellite alleles observed in 33.15 fingerprints. In a sample of 12 orange roughy collected on a single regional spawning site, the average percent similarity of 33.15 fingerprints was 21.15% (SD=17.75), the average percent similarity of 3HVR fingerprints was 14.32% (SD=14.45) and the inferred average allelic frequency of the M13 single-locus system was 0.071. A comparison of 33.15 and M13 fingerprints from two distant spawning sites ground New Zealand revealed no obvious regional differences. The variability of orange roughy fingerprints was so great, however, that regional comparisons could not be considered conclusive indicators of genetic identity. Our results provide a preliminary assessment of the power and pitfalls of using DNA-level markers for the population analysis of marine fish.     

Improving Objectives for Cleanup Sites

In 1976, the discovery of the Love Canal Superfund Site in New York thrust environmental cleanups into the forefront of the national conscience and essentially launched the remediation industry. Since then, vast efforts have been devoted to improving site remediation. Despite the attention given to key subject areas, such as site characterization, risk assessment, and remediation technologies, relatively little attention has been given to the objectives set forth for conducting cleanups, and they have generally not been rigorously evaluated in the literature. Several of the more common objectives for remediation projects are discussed. © 2014 Wiley Periodicals, Inc.