A comparison of sound propagation and song frequency in temperate marsh and grassland habitats

Summary Attenuation of pure tones was measured in marsh and grassland habitat. At surface level, in grassland, the ground effect strongly attenuated frequencies below 2.0 kHz (Fig. 2). The ground effect was reduced by increasing source-receiver elevation. In marsh habitat the ground effect did not occur, and low frequencies were optimal for sound propagation (Fig. 3). As predicted from sound propagation tests, analysis of recorded songs of seven grassland and six marsh species indicated that minimum and emphasized frequency were significantly lower in songs of marsh birds. Maximum frequency did not differ between habitats (Table 4). Buzzing songs of yellow-headed blackbirds were broadcast and re-recorded at 1 and 50 m from the speaker in marsh and grassland habitats. Low frequency components attenuated more rapidly than higher frequency components in grassland, and the reverse occurred in marsh. Results suggested that the ground effect restricts the use of low frequencies by grassland birds. This evidence is consistent with the sound window hypothesis of Morton.     

Disability among adults injured in motor-vehicle crashes in the United States

INTRODUCTION: Little population-based information exists about the long-term effects of motor-vehicle crash-related injuries. METHOD: We analyzed data from the 1995 National Health Interview Survey Disability (NHIS-D) Supplement to estimate the prevalence of crash-related disability among noninstitutionalized U.S. adults aged 18 years and older. RESULTS: More than 1.2 million adults were living in their homes with the disabling effects of motor-vehicle crash-related injuries in 1995. The prevalence of crash-related disability was highest for persons in their mid-life years, ages 35-64. Half of the respondents had sustained the injuries more than 5 years before the interview. Forty-one percent of working-aged individuals reported being unable to work because of their disability. CONCLUSIONS: Because crash-related disability is most prevalent during the mid-life years, quality of life and productivity may be affected for decades. These findings highlight the personal and societal burden associated with motor-vehicle crash-related disability in the United States.     

Preventing alcohol-related traffic injury: a health promotion approach

The conditions that give rise to drinking and driving are complex, with multiple and interrelated causes. Prevention efforts benefit from an approach that relies on the combination of multiple interventions. Health promotion provides a useful framework for conceptualizing and implementing actions to reduce drinking and driving since it involves a combination of educational, behavioral, environmental, and policy approaches. This review draws on data from a range of settings to characterize the effectiveness of various interventions embedded within the health promotion approach. Interventions considered part of the health promotion approach include: (1) economic interventions (2) organizational interventions, (3) policy interventions, and (4) health education interventions, including the use of media, school and community education, and public awareness programs. Effective health promotion strengthens the skills and capabilities of individuals to take action and the capacity of groups or communities to act collectively to exert control over the determinants of alcohol-impaired driving. There is strong evidence for the effectiveness of some components of health promotion, including economic and retailer interventions, alcohol taxation, reducing alcohol availability, legal and legislative strategies, and strategies addressing the servers of alcohol. There is also evidence for the effectiveness of sobriety checkpoints, lower BAC laws, minimum legal drinking age laws, and supportive media promotion programs. Other interventions with moderate evidence of effectiveness include restricting alcohol advertising and promotion, and actions involving counter advertising. Health education interventions alone that have insufficient evidence for effectiveness include passive server training programs, school drug and alcohol education programs, community mobilization efforts, and health warnings. Because each intervention builds on the strengths of every other one, ecological approaches to reducing alcohol-impaired driving using all four components of the health promotion model are likely to be the most effective. Settings such as schools, workplaces, cities, and communities offer practical opportunities to implement alcohol-impaired driving prevention programs within this framework.     

Preliminary Studies on Converting Agricultural Waste into Biodegradable Plastics,Part I: Corn Distillers’ Dry Grain

Distillers dry grain (DDG) was derivatized either by carboxymethylation, glutaration, maleiation, phthallation, or succination in order to produce anionic materials suitable for complexation with soy protein isolate. Infrared spectroscopy confirmed that derivatization of DDG by all reagents was successful. Blending of derivatized anionic products with soy protein resulted in instant precipitation of gels. The gels were centrifuged, molded, and dried into solid pellets with tensile strengths as high as 1.67MPa, suggesting that these materials could be promising as biodegradable structural materials. Infrared spectroscopy suggested the possibility of complexes forming between soy protein isolate and each of the derivatized DDG samples.     

Geographic variations in anthropogenic drivers that influence the vulnerability and resilience of social-ecological systems

Across the circumpolar North large disparities in the distribution of renewable and nonrenewable resources, human population density, capital investments, and basic residential and transportation infrastructure combine to create recognizable hotspots of recent and foreseeable change. Northern Fennoscandia exemplifies a relatively benign situation due to its current economic and political stability. Northern Russia is experiencing rapid, mostly negative changes reflecting the general state of crisis since the collapse of the Soviet Union. North America enjoys a relatively stable regulatory structure to mitigate environmental degradation associated with industry, but is on the verge of approving massive new development schemes that would significantly expand the spatial extent of potentially affected social-ecological systems. Institutional or regulatory context influences the extent to which ecosystem services are buffered against environmental change. With or without a warming climate, certain geographic areas appear especially vulnerable to damages that may threaten their ability to supply goods and services in the near future. Climate change may exacerbate this situation in some places but may offer opportunities to enhance resilience in the long term.     

Recent advances in aerial gamma-ray surveying

Aerial gamma-ray surveying uses NaI(Tl) detectors mounted in small aircraft to measure gamma radiation, emitted from the earth's surface. The data are collected as gamma-ray spectra, typically with 1 s counting times, from which are derived K, U and Th concentrations in the ground. Applications of aerial surveying include geological mapping for mineral exploration, soil mapping for agriculture, pollution studies and location of lost sources. Recent advances in applying statistical methods to the spectral data have resulted in large reductions in the noise levels in the surveys. Some of the methods available to do this include noise adjusted singular value decomposition (NASVD) [Proceedings of Exploration 97: Fourth Decennial International Conference on Mineral Exploration (1997) 753] and maximum noise fraction (MNF) and enhanced MNF (eMNF) [Explor. Geophys. 31 (2000) 73]. These methods, in general, apply normalization for variance to the spectra, use a principal component method to obtain the "significant" components of the data and reconstruct cleaned spectra, which are then processed in a standard manner to get radionuclide concentrations. However, they differ in the detail of the application and thus give slightly different results. In this paper, the application of noise reduction methods to various synthetic surveys is used to examine the strengths and weaknesses of the methods. In tests where there are high correlations between U and Th, the eMNF method performs best although the results are improved by prior clustering of the data by the Th/U ratio. If the data show no correlations, then the effectiveness of all the noise removal methods is reduced. If a data set is small (<1500 spectra), then MNF appears to be the better method. Consideration of the various tests suggests an optimum process whereby spectra are sorted into groups by the Th/U ratio of areas identified in a standard processing and then cleaned by eMNF or MNF, depending on the number of spectra in each group.     

UTILIZATION OF LANDSCAPE INDICATORS TO MODEL POTENTIAL PATHOGEN IMPAIRED WATERS1

ABSTRACT: Many water bodies within the United States are contaminated by non‐point source (NPS) pollution, which is defined as those materials posing a threat to water quality arising from a number of individual sources and diffused through hydrologic processes. One such NPS pollutant that is of critical concern are pathogens derived from animal wastes, including humans. The potential presence of pathogens is identified by testing the water for fecal conform, a bacteria also associated with animal wastes. Water contaminated by animal wastes are most often associated with urban and agricultural areas, thus it is postulated that by utilizing land cover indicators, those water bodies that may be at risk of fecal coliform contamination may be identified. This study utilizes land cover information derived from the Multi‐Resolution Land Characterization (MRLC) project to analyze fecal coliform contamination in South Carolina. Also utilized are 14 digit hydro‐logic unit code (HUC) watersheds of the state, a digital elevation model, and test point data stating whether fecal coliform levels exceeded State Water Quality Standards. Proportions of the various land covers are identified within the individual watersheds and then analyzed using a logistic regression. The results reveal that watersheds with large proportions of urban land cover and agriculture on steep slopes had a very high probability of being impaired. (KEY TERMS: Geographic Information Systems; land use planning; nonpoint source pollution; statistical analysis; water quality; watershed management.)     

A comparison of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) for monitoring chlorinated trace organic contaminants in Hong Kong coastal waters

A comparison of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) was carried out at five sites, representing a gradient of contaminant concentrations, in Hong Kong coastal waters. Mussels, originally collected from a “clean” location, were deployed along with SPMDs at each site for 30 days. Analyses for chlorinated pesticides and polychlorinated biphenyls (PCBs) indicated that SPMDs have potential as monitoring tools, and to some extent can overcome the problems associated with mussels, such as natural variability, differing age, sex, and physical condition. However, in most cases, SPMDs failed to rank the sites in the same order as mussels in terms of contaminant concentrations. Nonetheless, in localities where mussels cannot survive – as shown at Kwun Tong in the present experiment – SPMDs may be valuable in providing an indication of potentially bio-available lipophilic pollutants.     

Longevity can buffer plant and animal populations against changing climatic variability

Both means and year-to-year variances of climate variables such as temperature and precipitation are predicted to change. However, the potential impact of changing climatic variability on the fate of populations has been largely unexamined. We analyzed multiyear demographic data for 36 plant and animal species with a broad range of life histories and types of environment to ask how sensitive their long-term stochastic population growth rates are likely to be to changes in the means and standard deviations of vital rates (survival, reproduction, growth) in response to changing climate. We quantified responsiveness using elasticities of the long-term population growth rate predicted by stochastic projection matrix models. Short-lived species (insects and annual plants and algae) are predicted to be more strongly (and negatively) affected by increasing vital rate variability relative to longer-lived species (perennial plants, birds, ungulates). Taxonomic affiliation has little power to explain sensitivity to increasing variability once longevity has been taken into account. Our results highlight the potential vulnerability of short-lived species to an increasingly variable climate, but also suggest that problems associated with short-lived undesirable species (agricultural pests, disease vectors, invasive weedy plants) may be exacerbated in regions where climate variability decreases.     

Phenology of mixed woody-herbaceous ecosystems following extreme events: net and differential responses

Ecosystem responses to key climate drivers are reflected in phenological dynamics such as the timing and degree of "green-up" that integrate responses over spatial scales from individual plants to ecosystems. This integration is clearest in ecosystems dominated by a single species or life form, such as seasonally dynamic grasslands or more temporally constant evergreen forests. Yet many ecosystems have substantial contribution of cover from both herbaceous and woody evergreen plants. Responses of mixed woody-herbaceous ecosystems to climate are of increasing concern due to their extensive nature, the potential for such systems to yield more complex responses than those dominated by a single life form, and projections that extreme climate and weather events will increase in frequency and intensity with global warming. We present responses of a mixed woody-herbaceous ecosystem type to an extreme event: regional-scale pi?on pine mortality following an extended drought and the subsequent herbaceous green-up following the first wet period after the drought. This example highlights how reductions in greenness of the slower, more stable evergreen woody component can rapidly be offset by increases associated with resources made available to the relatively more responsive herbaceous component. We hypothesize that such two-phase phenological responses to extreme events are characteristic of many mixed woody-herbaceous ecosystems.