Evaluation of geomorphic changes and retreat rates of a coastal pyroclastic cliff in the Campi Flegrei volcanic district,southern Italy

Geomorphic evolution of sea cliffs has significant impact on coastal settlements worldwide, so that evaluation of cliff instability processes, failure factors, and retreat rates involves a growing number of scientists for coastal risk and management purposes. Aerial photogrammetry and lidar are among the most used techniques for topographic characterization and geomorphic monitoring of coastal environments. A crucial role in the combined use of such techniques is the evaluation of different spatial accuracy and co-registration between derived terrain models, so that a robust error analysis is required. In this study, we present a change detection analysis of the Torrefumo coastal cliff, in the Campi Flegrei volcanic area (Southern Italy). Aerial images taken in 1956 and 1974, processed through digital photogrammetry, and an airborne lidar point cloud acquired in 2008 were used to produce Digital Elevation Models of the cliff. The analysis was based on the multi-temporal comparison of these models and included the calculation of volumetric changes and average retreat rates of the cliff face with reference to the 1956–1974 and 1974–2008 time intervals. The spatially variable elevation uncertainty of each Digital Elevation Model was evaluated with a probabilistic approach based on the fuzzy set theory. The results of this study showed significant eroded volumes during the period 1956–1974 and relatively smaller volumes in the 1974–2008 time span, with mean annual retreat rates of 1.2 m/year and 0.17 m/year, respectively. We infer that the significant decrease of erosion characterizing the second period was induced by the sheltering effect at the base of the cliff produced by the construction of a seawall in the early 80’s.     

When creativity enhances sales effectiveness: The moderating role of leader–member exchange

This study extends research on creativity by exploring the boundary conditions of the creativity–job effectiveness relationship. Building on social exchange theory, we argue that the extent to which employee creativity is related to sales—an objective work effectiveness measure—depends on the quality of leader–member exchange (LMX). We hypothesize that the relationship between creativity and sales is significant and positive when LMX is high, but not when LMX is low. Hierarchical linear modelling analysis provided support for the interaction hypothesis in a sample of 151 sales agents and 26 supervisors drawn from both pharmaceutical and insurance companies. Results showed that sales agents who were more creative generated higher sales only when they had high‐quality LMX. An ad hoc qualitative study provided a more detailed understanding of the moderator role played by LMX. Copyright © 2012 John Wiley & Sons, Ltd.     

“At the water's edge”: community voices on climate change

The photovoice research project, “At the water's edge”, which gives voice to communities exploring the threats and impact of climate change and rising sea levels on coastal communities, was conducted during an environmental art symposium in the Noosa Biosphere Reserve, Australia in June 2009. Photos by participants illustrated both local and global threats and reflected psychological tension between global and local action. This research partnership with the local people demonstrated an innovative visualisation technique which can be used to collaboratively build capacity and consensus about adaptation to climate change. It also contributed to the Biosphere Reserve's educational and cultural aims in relation to climate change.     

Controlling urban air pollution caused by households: uncertainty, prices, and income

We examine the control of air pollution caused by households burning wood for heating and cooking in the developing world. Since the problem is one of controlling emissions from nonpoint sources, regulations are likely to be directed at household choices of wood consumption and combustion technologies. Moreover, these choices are subtractions from, or contributions to, the pure public good of air quality. Consequently, the efficient policy design is not independent of the distribution of household income. Since it is unrealistic to assume that environmental authorities can make lump sum income transfers part of control policies, efficient control of air pollution caused by wood consumption entails a higher tax on wood consumption and a higher subsidy for more efficient combustion technologies for higher income households. Among other difficulties, implementing a policy to promote the adoption of cleaner combustion technologies must overcome the seemingly paradoxical result that efficient control calls for higher technology subsidies for higher income households.     

Microsatellite data reveal fine genetic structure in male Guiana dolphins (<Emphasis Type="Italic">Sotalia guianesis)</Emphasis> in two geographically close embayments at south-eastern coast of Brazil

A large macrogeographic differentiation has been observed among Sotalia guianensis populations along the South American coast. However, no genetic structure has been detected so far in closely distributed populations of this species, even though it has been observed in other cetaceans. Here, we examined the fine scale population structure for the largest populations of S. guianensis inhabiting Sepetiba and Paraty embayments at the south-eastern coast of Rio de Janeiro, Brazil. Analysis of mitochondrial DNA (mtDNA) control region sequences failed to detect variability among sequences. Conversely, evidence of significant male population structure was found on the basis of ten nuclear microsatellite loci. Surprisingly, the microsatellite markers were able to distinguish between individuals from the two embayments located 60 km apart. The results suggest that differences in habitat type and behavioral specializations are likely to explain the patterns of genetic structure. These findings should provide baselines for the management of communities exposed to increasing human-driven habitat loss.     

Lock-release gravity currents propagating over roughness elements

Environmental Fluid Mechanics - The influence of bottom roughness on the development of lock-release gravity currents is investigated through laboratory experiments using Particle Image...     

Bioassay-guided isolation of allelochemicals from Avena sativa L.: allelopathic potential of flavone C-glycosides

The allelopathic potential of oat (Avena sativa L., var. Argentina, Poaceae, Cyperales) was investigated under field and laboratory conditions. In field trials, oat plants provided an effective control of weeds, showing a species-specific impact: the most abundant weed species, Picris echioides was reduced by 94% in number of individuals. Aerial parts of oat plants, harvested immediately before soil incorporation, were utilized in a bioassay-guided isolation, which was aimed at identifying the phytotoxic compounds in a methanol/water extract of the aerial parts of the plants. Further partitions of extract gave an active n-butanol portion composed of flavonoids and saponins. Phytotoxic activity was detected for the flavonoid fraction, whereas no activity was found for the saponin mixture. Germination of an indicator species, lettuce (Lactuca sativa L.), was completely inhibited at flavonoid concentrations of 6.7, 10.0, and 20.0 mg/mL, and conversely the number of abnormal seedlings was greatly increased from 2% of control to over 96% at concentrations equal to 6.7 and 10.0 mg/mL. Analysis of the flavonoid fraction by ESI-MS techniques identified two components of the mixture as isoorientin 2-O-glucoside and isovitexin 2″-O-arabinoside. Saponins were characterized as avenacoside A, avenacoside B, 26-desglucoavenacoside A, and 26-desglucoavenacoside B. Both flavone C-glycosides and saponins were isolated previously from oat.     

Kinetics and thermodynamic studies of Methyl Orange removal by polyvinylidene fluoride-PEDOT mats

We report the preparation of poly(3,4-ethylene dioxythiophene) (PEDOT)-modified polyvinylidene fluoride electrospun fibers and their use as a novel adsorbent material for the removal of the anionic dye Methyl Orange (MO) from aqueous media. This novel adsorbent material can be used to selectively remove MO on a wide pH range (3.0–10.0), with a maximum capacity of 143.8 mg/g at pH 3.0. When used in a recirculating filtration system, the maximum absorption capacity was reached in a shorter time (20 min) than that observed for batch mode experiments (360 min). Based on the analyses of the kinetics and adsorption isotherm data, one can conclude that the predominant mechanism of interaction between the membrane and the dissolved dye molecules is electrostatic. Besides, considering the estimated values for the Gibbs energy, and entropy and enthalpy changes, it was established that the adsorption process is spontaneous and occurs in an endothermic manner. The good mechanical and environmental stability of these membranes allowed their use in at least 20 consecutive adsorption/desorption cycles, without significant loss of their characteristics. We suggest that the physical-chemical characteristics of PEDOT make these hybrid mats a promising adsorbent material for use in water remediation protocols and effluent treatment systems.     

Mapping Adolescents’ Sense of Place and Perceptions of Change in an Urban–Rural Transition Area

Environmental Management - Landscapes are changing, with rural areas becoming increasingly urbanized. Children and adolescents are underrepresented in the sense-of-place literature. Our study aimed...     

The probabilistic tsunami hazard assessment along Karnataka Coast from Makran Subduction Zone,west coast of India

Coastal tsunami amplitudes were calculated to identify areas susceptible to tsunami hazard at selected locations of the coast of Karnataka, west of India, due to earthquakes in the Makran Subduction Zone. This is the first time that the probabilistic tsunami hazard assessment along this study area has been attempted. A series of earthquake source scenarios with magnitudes of Mw 8.0, Mw 8.5, and a mega thrust of Mw 9.1 were modeled by using the Community Model Interface for Tsunami interface with the MOST model of Titov and Synolakis (J. Waterway, Port, Coastal and Ocean Engineering, 121(6), 308–316, 1995). As per the previous occurrences, the two least magnitudes are probable, while Mw 9.1 is a worst-case scenario as described by Heidarzadeh et al. (Ocean Engineering, 36(5), 368–376, 2009) and the same is reported by Burbidge et al. (Geoscience Australia Professional Opinion No. 2009/11) as high magnitude. These are not at all historical earthquakes or specifically from historical catalogues. The results of modeling show that all the seven coastal locations are inundated barely in our worst-case scenario with maximum water levels in the range of 100–200 cm. The first tsunami wave strikes the coast within 4–5 h of earthquake occurrence.