Encounter rate and task allocation in harvester ants

As conditions change, social insect colonies adjust the numbers of workers engaged in various tasks, such as foraging and nest work. This process of task allocation operates without central control; individuals respond to simple, local cues. This study investigates one such cue, the pattern of an ant's interactions with other workers. We examined how an ant's tendency to perform midden work, carrying objects to and sorting the refuse pile of the colony, is related to the recent history of the ant's brief antennal contacts, in laboratory colonies of the red harvester ant, Pogonomyrmex barbatus. The probability that an ant performed midden work was related to its recent interactions in two ways. First, the time an ant spent performing midden work was positively correlated with the number of midden workers that ant had met while it was away from the midden. Second, ants engaged in a task other than midden work were more likely to begin to do midden work when their rate of encounter per minute with midden workers was high. Cues based on interaction rate may enable ants to respond to changes in worker numbers even though ants cannot count or assess total numbers engaged in a task. Received: 1 July 1998 / Accepted: 15 November 1998     

(De)legitimating extractivism: the shifting politics of social licence

ABSTRACT

Most scholarly accounts of social licence define it as a public relations strategy to legitimate resource development. In Canadian pipeline politics, however, it has had the opposite effect, crystallizing widespread concerns about industry capture of regulatory processes and affirming the democratic rights of local communities. This assessment of the concept’s critical, counter-hegemonic potential to challenge the policies, practices and logic of state-sponsored extractivist development situates social licence as a key discursive battleground in the struggle between politicization (which accents agonistic confrontation between competing alternative futures) and de-politicization (which defuses conflict and builds consensus around the perception of common interests). Frame analysis of news media and advocacy group texts is used to investigate how opponents of a pipeline project bridged the idea of social licence with movement frames concerning identity, injustice and democratic agency to transform the concept from a public relations term meant to enable corporate activity into a critical trope used to constrain it.     

Thanks but no thanks: A new policy to reduce land conflict

Land conflicts in developing countries are costly both directly and through increased land degradation. An important policy goal is to create respect for borders. This often involves mandatory, expensive interventions. We propose a new policy design, which in theory promotes neighborly relations at low cost. A salient feature is the option to by-pass regulation through consensus. The key idea combines the insight that social preferences transform social dilemmas into coordination problems with the logic of forward induction. As a first, low-cost pass at empirical evaluation, we conduct an experiment among farmers in the Ethiopian highlands, a region exhibiting features typical of countries where borders are often disputed.     

Flash flood mitigation: recommendations for research and applications

Abstract

New technologies promise reduced flash flood losses. However, real-time observations with vast multi-sensor networks, more precise mapping capabilities using remote sensing and GIS, quicker hydrological and meteorological models, and increasing forecast lead times have not reduced losses. In November, 1999, 35 researchers from nine countries met in Ravello, Italy at a NATO sponsored Advanced Study Institute, to discuss these issues and to develop a research agenda that incorporates the various components required to cope with flash floods. The key recommendations from the Institute were: (1) greater emphasis on increasing understanding of the social processes involved in flash flood warning, particularly in the response phases, and (2) the need to reduce vulnerability in sustainable ways compatible with long-term economic and social goals. The relationship between hydrometeorology and social science is seen as critical to advancing our abilities to cope with flash floods.     

Analysis of underlying causes of investigated loss of containment incidents in Dutch Seveso plants using the Storybuilder method

In the Netherlands there are around 400 “Seveso” sites that fall under the Dutch Major Hazards Decree (BRZO) 1999. Between 2006 and 2010 the Dutch Labour Inspectorate's Directorate for Major Hazard Control completed investigations of 118 loss of containment incidents involving hazardous substances from this group. On the basis of investigation reports the incidents were entered in a tailor-made tool called Storybuilder developed for the Dutch Ministry of Social Affairs and Employment for identifying the dominant patterns of technical safety barrier failures, barrier task failures and underlying management causes associated with the resulting loss of control events. The model is a bow-tie structure with six lines of defence, three on either side of the central loss of containment event. In the first line of defence, failures in the safety barriers leading to loss of control events were primarily equipment condition failures, pre start-up and safeguarding failures and process deviations such as pressure and flow failures. These deviations, which should have been recovered while still within the safe envelope of operation, were missed primarily because of inadequate indication signals that the deviations have occurred. Through failures of subsequent lines of defence they are developing into serious incidents. Overall, task failures are principally failures to provide adequate technical safety barriers and failures to operate provided barriers appropriately. Underlying management delivery failures were mainly found in equipment specifications and provisions, procedures and competence. The competence delivery system is especially important for identifying equipment condition, equipment isolation for maintenance, pre-start-up status and process deviations. Human errors associated with operating barriers were identified in fifty per cent of cases, were mostly mistakes and feature primarily in failure to prevent deviations and subsequently recover them. Loss of control associated with loss of containment was primarily due to the containment being bypassed (72% of incidents) and less to material strength failures (28%). Transfer pipework, connections in process plant and relief valves are the most frequent release points and the dominant release material is extremely flammable. It is concluded that the analysis of a large number of incidents in Storybuilder can support the quantification of underlying causes and provide evidence of where the weak points exist in major hazard control in the prevention of major accidents.     

Nestmate recognition in ants is possible without tactile interaction

Ants of the genus Camponotus are able to discriminate recognition cues of colony members (nestmates) from recognition cues of workers of a different colony (non-nestmates) from a distance of 1 cm. Free moving, individual Camponotus floridanus workers encountered differently treated dummies on a T-bar and their behavior was recorded. Aggressive behavior was scored as mandibular threat towards dummies. Dummies were treated with hexane extracts of postpharyngeal glands (PPGs) from nestmates or non-nestmates which contain long-chain hydrocarbons in ratios comparable to what is found on the cuticle. The cuticular hydrocarbon profile bears cues which are essential for nestmate recognition. Although workers were prevented from antennating the dummies, they showed significantly less aggressive behavior towards dummies treated with nestmate PPG extracts than towards dummies treated with non-nestmate PPG extracts. In an additional experiment, we show that cis-9-tricosene, an alkene naturally not found in C. floridanus' cuticular profile, is behaviorally active and can interfere with nestmate recognition when presented together with a nestmate PPG extract. Our study demonstrates for the first time that the complex multi-component recognition cues can be perceived and discriminated by ants at close range. We conclude that contact chemosensilla are not crucial for nestmate recognition since tactile interaction is not necessary.     

Investigating the relationship between air pollution, health and social deprivation in Leeds, UK

This study examines the relationship between air pollution, social deprivation and health in the city of Leeds, UK under a baseline and three distance-based road user charging (RUC) scenarios set at 2 pence, 10 pence and 20 pence/km. Through application of a series of linked models of traffic, emission and pollutant dispersion, air quality was modelled in response to RUC scenarios. The pollutant modelled were NO(2), PM(10), CO, benzene and 1,3-butadiene, though results of NO(2) are used in this study. The RUC scenarios were compared with the 'base' scenario, all set for the year 2005. The RUC initiatives result in the differences in ambient concentrations of NO(2). The study correlates NO(2) concentrations with derived indices of social deprivation and health. The study concludes that positive but weak relationship exists between air quality and social deprivation, and indicates that deprived population groups are disproportionately exposed to higher NO(2) levels. The relationship between air quality and health status of the population is weak. There is a strong relationship between social deprivation and health status of the population. The study concludes that RUC scenarios result in reducing disparity between affluent and deprived populations.     

The Flood Myth in the Age of Global Climate Change

When released, The Day After Tomorrow was widely described by critics and the movie's creators as a pro-environmentalist film. This essay argues that The Day After Tomorrow articulates a variation of apocalyptic discourse identified as a flood myth. The authors conclude that this version of the flood myth largely undermines contemporary environmental discourse that attempts to generate public activism in addressing ecological problems, by replacing an emphasis on human efficacy with symbolic vindication and exchanging collective effort for individual survivalism. The film thus serves as a cautionary tale about the potential consequences of contemporary mythic discourse presented as supporting environmental activism.     

From Environmental Campaigns to Advancing the Public Dialog: Environmental Communication for Civic Engagement

This essay examines the claims of environmental identity campaigns regarding the issue of climate change. Identity campaigns are based on the idea that more effective environmental messages developed through the application of cognitive science by professional communications experts can favorably influence public opinion, and thus support legislative action to remedy this issue. Based on a review of the sociological and psychological literature regarding social change and mobilization, I argue that while this approach may offer short term advantages, it is most likely incapable of developing the large scale mobilization necessary to enact the massive social and economic changes necessary to address global warming. Specifically, theoretical and empirical research on the role of the public sphere, civil society and social movements shows that democratic civic engagement is core to successful social change efforts. However, identity campaigns focus on a communications process that centers on elite led one way communications, which falls to allow for any form of civic engagement and public dialogue. This undermines the creation of a democratic process of change and reinforces the professionalization of political discourse, leading to a weakening of the mobilization capacity over this issue of global warming. The essay concludes with the outlines of an environmental communication process that aims at enhancing civic engagement and democratic decision making.     

New methods for the analysis of invasion processes: multi-criteria evaluation of the invasion of Hydrilla verticillata in Guatemala

The study described in this article incorporates stakeholders' views on aquatic invasion processes and combines expert analysis with information from field work into an evaluation exercise. Management scenarios are designed based on available technical data and stakeholders' perceptions. These scenarios are evaluated using the Social Multi-Criteria Evaluation framework employing the NAIADE model. Two evaluations are carried out, technical and social. Social acceptance of different management scenarios, distribution of costs and benefits, and attribution of responsibility are discussed. The case study was carried out on Lake Izabal, a body of water connected to the Caribbean Sea in Northeastern Guatemala. In 2000, local fishermen reported the presence of an alien species in the lake, the macrophyte Hydrilla verticillata. Two years later, this alien species was established around the entire lakeshore, damaging the ecosystem, endangering native species and the subsistence of local inhabitants through impacts on transportation, fishing practices, and tourism.