Soil carbon stock estimations: methods and a case study of the Maranhão State,Brazil

Environment, Development and Sustainability - Soils feature significant variations in soil carbon stocks through land-use changes, management practices, and intrinsic characteristics. The aim of...     

What is this thing called a safety regulation?

Regulation is generally perceived as an important way to achieve safety. Controversy about enforcing, amending, reforming, reducing, improving, and evaluating safety regulations abounds. Questions about the need for, validity, and effectiveness of safety regulations also continue. This paper explores the nature of a safety regulation, what can be expected of a safety regulation in view of its nature, and what this means to persons affected by safety regulation. The role of regulation in safe task performance is reviewed. Consequences of these findings on regulation promulgation, employee training, and regulatory enforcement programs are discussed. Steps to enhance the effectiveness of safety regulations are suggested.     

Modeling the Ecological Consequences of Land-Use Policies in an Urbanizing Region

Insight into future land use and effective ways to control land-use change is crucial to addressing environmental change. A variety of growth-control policies have been adopted by municipal and regional governments within the United States to try to minimize the ecological impact of continued urbanization, but it is often unclear if those policies can meet the stated ecological goals. Land-use-change models provide a way to generate predictions of future change, while exploring the impact of different land-use policies before irreversible transformations occur. In this article, an approach to modeling land-use policies that focuses on their ecological consequences is described. The policy simulation approach was used to predict future land use in the Barnegat Bay and Mullica River watersheds, in southeastern New Jersey, USA. Four commonly used policies were considered: down-zoning, cluster development, wetlands/water buffers, and open space protection. The results of the analysis suggest that none of the policies modeled were able to alter future land-use patterns, raising questions about the effectiveness of commonly adopted land-use policies. However, the policy modeling approach used in this study proved to be a useful way to determine if adoption of a given policy could improve the likelihood of meeting ecological goals.     

Spatial Distribution of Soil Attributes in the Concórdia River Watershed in Southern Brazil

Using geographic information system, soil sampling, and statistical analysis to map anthropogenic effects on soil     

Effects of sample survey design on the accuracy of classification tree models in species distribution models

We evaluated the effects of probabilistic (hereafter DESIGN) and non-probabilistic (PURPOSIVE) sample surveys on resultant classification tree models for predicting the presence of four lichen species in the Pacific Northwest, USA. Models derived from both survey forms were assessed using an independent data set (EVALUATION). Measures of accuracy as gauged by resubstitution rates were similar for each lichen species irrespective of the underlying sample survey form. Cross-validation estimates of prediction accuracies were lower than resubstitution accuracies for all species and both design types, and in all cases were closer to the true prediction accuracies based on the EVALUATION data set. We argue that greater emphasis should be placed on calculating and reporting cross-validation accuracy rates rather than simple resubstitution accuracy rates. Evaluation of the DESIGN and PURPOSIVE tree models on the EVALUATION data set shows significantly lower prediction accuracy for the PURPOSIVE tree models relative to the DESIGN models, indicating that non-probabilistic sample surveys may generate models with limited predictive capability. These differences were consistent across all four lichen species, with 11 of the 12 possible species and sample survey type comparisons having significantly lower accuracy rates. Some differences in accuracy were as large as 50%. The classification tree structures also differed considerably both among and within the modelled species, depending on the sample survey form. Overlap in the predictor variables selected by the DESIGN and PURPOSIVE tree models ranged from only 20% to 38%, indicating the classification trees fit the two evaluated survey forms on different sets of predictor variables. The magnitude of these differences in predictor variables throws doubt on ecological interpretation derived from prediction models based on non-probabilistic sample surveys.     

Triploidy: Pregnancy complications and clinical findings in seven cases

Seven cases of triploidy were encountered by the Prenatal Diagnosis Program at Dartmouth–Hitchcock Medical Center over an 8-year period through associated pregnancy complications. We describe the characteristic findings that facilitate prenatal diagnosis and management. Our experience includes fetuses with major central nervous system abnormalities (spina bifida aperta, holoprosencephaly) and anterior abdominal wall defects, which are detectable with routine prenatal diagnostic screening examinations (ultrasound and AFP). In addition, we stress the importance of recognizing obstetric complications and associated cystic placental changes, which are quite common among triploid conceptuses. Molar changes associated with triploidy have a more benign prognosis than that associated with diploid moles. Such molar changes may relate to the presence of a diploid paternal chromosome complement. The usefulness of cytofluorometric DNA determinations in helping to confirm a clinical suspicion of triploidy is emphasized. These cases are presented in an effort to facilitate prenatal recognition and management of this common cytogenetic condition and prevent unnecessary Caesarean section deliveries.     

Fine-scale,spatial and temporal assessment methods for feral swine disturbances to sensitive plant communities in south-central Florida

Feral swine are estimated to annually cost hundreds of millions of dollars in economic loss to property and agriculture in the USA, while their ecological consequences remain largely unmeasured. Using submeter-accurate Global Positioning System technology over a multiyear project, we are quantifying in a novel way the spatial and temporal attributes of swine rooting damage within 587 ha of ecologically sensitive wetland plant communities at Avon Park Air Force Range in south-central Florida. We delineated damage polygons from 0.0023 to 4,335 m² and were able to document recurrent damage through time at most sites during each assessment. For each polygon, we also estimated the age of damage and assigned to it a severity index, qualities of the rooting in which we detected changes in proportions over time. Spatially explicit damage assessments at fine scales conducted over several years can assist land managers in determining effects of rooting on rare plant populations, and will allow investigators to hypothesize what factors are driving patterns of this disturbance across ecologically sensitive plant communities.     

Are consumers willing to pay for conservation agriculture? The case of white maize in the Democratic Republic of the Congo

Throughout the low-income world, agricultural producers have a motivation to slash-and-burn rainforests as they cannot afford inorganic fertilizers. Farmers in the Democratic Republic of the Congo (DRC), who are predominantly women, are often forced to walk long distances to cultivate more productive lands, when fertility near their villages is reduced. On their way and while working away from home, women become targets for rape. Adopting conservation agriculture (CA) could help mitigate deforestation and potentially create a safer environment for women. Limited knowledge about the benefits of CA across countries in Sub-Saharan Africa (SSA) has hindered its adoption. Taking these impediments into account, we estimate if consumers in the DRC are willing to pay (WTP) a premium for CA, using maize flour as the medium. By means of a double-bounded dichotomous choice valuation method, 600 consumers in Bukavu, DRC, were surveyed about their willingness-to-pay for CA-produced maize. Our study finds that only those consumers who identify themselves as farmers are WTP a premium. This study indicates that if CA adoption is to spread in the DRC, it will likely need to happen via increased yields or reduced costs before the farm gate and not premiums after the farm gate.