Dental fluorosis linked to degassing of Ambrym volcano, Vanuatu: a novel exposure pathway

Ambrym in Vanuatu is a persistently degassing island volcano whose inhabitants harvest rainwater for their potable water needs. The findings from this study indicate that dental fluorosis is prevalent in the population due to fluoride contamination of rainwater by the volcanic plume. A dental survey was undertaken of 835 children aged 6–18 years using the Dean’s Index of Fluorosis. Prevalence of dental fluorosis was found to be 96% in the target area of West Ambrym, 71% in North Ambrym, and 61% in Southeast Ambrym. This spatial distribution appears to reflect the prevailing winds and rainfall patterns on the island. Severe cases were predominantly in West Ambrym, the most arid part of the island, and the most commonly affected by the volcanic plume. Over 50 km downwind, on a portion of Malakula Island, the dental fluorosis prevalence was 85%, with 36% prevalence on Tongoa Island, an area rarely affected by volcanic emissions. Drinking water samples from West Ambrym contained fluoride levels from 0.7 to 9.5 ppm F (average 4.2 ppm F, n = 158) with 99% exceeding the recommended concentration of 1.0 ppm F. The pathway of fluoride-enriched rainwater impacting upon human health as identified in this study has not previously been recognised in the aetiology of fluorosis. This is an important consideration for populations in the vicinity of degassing volcanoes, particularly where rainwater comprises the primary potable water supply for humans or animals.     

The effectiveness of surrogate taxa to conserve freshwater biodiversity

Establishing protected areas has long been an effective conservation strategy and is often based on readily surveyed species. The potential of any freshwater taxa to be a surrogate for other aquatic groups has not been explored fully. We compiled occurrence data on 72 species of freshwater fishes, amphibians, mussels, and aquatic reptiles for the Great Plains, Wyoming (U.S.A.). We used hierarchical Bayesian multispecies mixture models and MaxEnt models to describe species’ distributions and the program Zonation to identify areas of conservation priority for each aquatic group. The landscape‐scale factors that best characterized aquatic species’ distributions differed among groups. There was low agreement and congruence among taxa‐specific conservation priorities (<20%), meaning no surrogate priority areas would include or protect the best habitats of other aquatic taxa. Common, wideranging aquatic species were included in taxa‐specific priority areas, but rare freshwater species were not included. Thus, the development of conservation priorities based on a single freshwater aquatic group would not protect all species in the other aquatic groups.     

Identifying and Evaluating a Suitable Index for Agricultural Drought Monitoring in the Texas High Plains

Drought is a complex and highly destructive natural phenomenon that affects portions of the United States almost every year, and severe water deficiencies can often become catastrophic for agricultural production. Evapotranspiration (ET) by crops is an important component in the agricultural water budget; thus, it is advantageous to include ET in agricultural drought monitoring. The main objectives of this study were to (1) conduct a literature review of drought indices with a focus to identify a simple but simultaneously adequate drought index for monitoring agricultural drought in a semiarid region and (2) using the identified drought index method, develop and evaluate time series of that drought index for the Texas High Plains. Based on the literature review, the Standardized Precipitation‐Evapotranspiration Index (SPEI) was found to satisfy identified constraints for assessing agricultural drought. However, the SPEI was revised by replacing reference ET with potential crop ET to better represent actual water demand. Data from the Texas High Plains Evapotranspiration network was used to calculate SPEIs for the major irrigated crops. Trends and magnitudes of crop‐specific, time‐series SPEIs followed crop water demand patterns for summer crops. Such an observation suggests that a modified SPEI is an appropriate index to monitor agricultural drought for summer crops, but it was found to not account for soil water stored during the summer fallow period for winter wheat.     

Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution.     

Preventing impaired driving using alcohol policy

Considerable progress has been made in the reduction of impaired driving crashes during the last two decades. Much of this progress is attributable to strengthening laws against impaired driving along with vigorous enforcement efforts aimed at deterring impaired driving. In addition, many useful strategies can also be applied that focus on the control of alcohol availability, use, and promotion. Alcohol policies include controls on the price of alcohol, the location, density, and opening hours of sales outlets, controls on the social availability of alcohol, and on the promotion and advertising of alcohol. Enforcement of these policies is an important aspect of their effectiveness. These strategies have been shown to be effective or promising in reducing impaired driving as well as other consequences related to alcohol use and misuse.     

A biosocial model of entrepreneurship: the combined effects of nurture and nature

Why do people get involved in the creation of new ventures? Prior research suggests entrepreneurial behavior has multiple causes. Nurture explanations; often couched in terms of sociological theories like social learning have been popular. Aspects of nascent entrepreneurs' social contexts, notably their family business background, have been associated with new venture creation. But nature also appears to play a role. Other research has linked heritable biological factors, including testosterone, with the career choice to launch a new venture. This study presents theory and evidence linking the combination of both sociological and biological factors with new venture creation: a biosocial model of entrepreneurship. Empirical results indicate new venture creation is more likely among those individuals having a higher testosterone level in combination with a family business background. Copyright © 2007 John Wiley & Sons, Ltd.     

Sustainable sanitary landfills for neglected small cities in developing countries: The semi-mechanized trench method from Villanueva,Honduras

Open dumping is the most common practice for the disposal of urban solid wastes in the least developed regions of Africa, Asia and Latin America. Sanitary landfill design and operation has traditionally focused on large cities, but cities with fewer than 50,000 in population can comprise from 6% to 45% of a given country’s total population. These thousands of small cities cannot afford to operate a sanitary landfill in the way it is proposed for large cities, where heavy equipment is used to spread and compact the waste in daily cells, and then to excavate, transport and apply daily cover, and leachate is managed with collection and treatment systems. This paper presents an alternative approach for small cities, known as the semi-mechanized trench method, which was developed in Villanueva, Honduras. In the semi-mechanized trench method a hydraulic excavator is used for 1–3 days to dig a trench that will last at least a month before it is filled with waste. Trucks can easily unload their wastes into the trench, and the wastes compact naturally due to semi-aerobic biodegradation, after which the trenches are refilled and covered. The exposed surface area is minimal since only the top surface of the wastes is exposed, the remainder being covered by the sides and bottom of the trench. The surplus material from trench excavation can be valorized for use as engineering fill onsite or off. The landfill in Villanueva has operated for 15 years, using a total land area of approximately 11 ha for a population that grew from 23,000 to 48,000, with a land requirement of 0.2 m²/person year, a cover to waste ratio of 0.2, and an estimated soil surplus of 298,000 m³ that is valorized and used onsite. The landfill has been operated solely by the municipality with an operational cost in 2010 estimated at US$4.60 per ton. A modified water balance analysis at Villanueva shows negligible leachate generation from covered trenches and 700 m³/yr (60 m³/ha yr) from the two open trenches required for daily operation. If the site were an open dump, however, leachate generation is estimated to be 3900 m³/ha yr and contaminated runoff 5000 m³/ha yr. A simple model used to estimate dilution of generated leachate based on groundwater flow data and aquifer stratigraphy suggests that the leachate will be diluted by a factor of 0.01 in the aquifer. Leachate contaminants will not accumulate because the aquifer discharges to the Ulua River 2 km south of the landfill. While not suitable for all sites, the Villanueva method nevertheless serves as an excellent example of how a small city landfill with natural compaction of waste and attenuation of leachate can be sustainably operated.     

Pelleted organo-mineral fertilisers from composted pig slurry solids, animal wastes and spent mushroom compost for amenity grasslands

In Ireland, conversion of biodegradable farm wastes such as pig manure spent mushroom compost and poultry litter wastes to pelletised fertilisers is a desirable option for farmers. In this paper, results obtained from the composting of pig waste solids (20% w/w) blended with other locally available biodegradable wastes comprising poultry litter (26% w/w), spent mushroom compost (26% w/w), cocoa husks (18% w/w) and moistened shredded paper (10% w/w) are presented. The resulting 6-mo old 'mature' composts had a nutrient content of 2.3% total N, 1.6% P and 3.1% K, too 'low' for direct use as an agricultural fertiliser. Formulations incorporating dried blood or feather meal amendments enriched the organic N-content, reduced the moisture in mature compost mixtures and aided the granulation process. Inclusion of mineral supplements viz., sulphate of ammonia, rock phosphate and sulphate of potash, yielded slow release fertilisers with nutrient N:P:K ratios of 10:3:6 and 3:5:10 that were suited for amenity grasslands such as golf courses for spring or summer application and autumn dressing, respectively. Rigorous microbiological tests carried out throughout the composting, processing and pelletising phases indicated that the formulated organo-mineral fertilisers were free of vegetative bacterial pathogens.     

Osmotic adjustment and organic solute accumulation in unicellular cyanobacteria from freshwater and marine habitats

The intracellular concentrations of low-molecular weight carbohydrates and quaternary ammonium compounds present in 26 axenic isolates of unicellular cyanobacteria have been studied over a range of external salinity from freshwater up to 300% seawater (100%=35 S). In all cases, a single carbohydrate, either sucrose or glucosylglycerol, was identified as the principal organic osmoticum, showing major variation in response to the external salt concentration; quaternary ammonium compounds were present in osmotically insignificant amounts. Glucosylglycerol was accumulated as primary osmoticum by nine of the isolates from saline habitats and by five of the freshwater isolates; trace amounts of sucrose were also prsent. The remaining twelve freshwater strains accumulated sucrose as sole osmoticum. Glucosylglycerol-accumulating strains grew over the widest salinity range (up to 200 to 250% seawater), whether isolated from saline or non-saline habitats. Sucrose-accumulating strains were more stenohaline, growing only in up to 50 to 100% seawater and showing no sustained growth in hypersaline media (>100% seawater). The data suggest that (1) glycosylglycerol accumulation is not unique to marine cyanobacteria, and (2) the upper salinity limit for growth may be linked to organic solute accumulation, rather than habitat, with glucosylglycerol-accumulating isolates having a greater potential for growth in salt-stressed conditions than sucrose accumulators.