Aquatic macroinvertebrate responses to native and non-native predators

Non-native species can profoundly affect native ecosystems through trophic interactions with native species. Native prey may respond differently to non-native versus native predators since they lack prior experience. Here we investigate antipredator responses of two common freshwater macroinvertebrates, Gammarus pulex and Potamopyrgus jenkinsi, to olfactory cues from three predators; sympatric native fish (Gasterosteus aculeatus), sympatric native crayfish (Austropotamobius pallipes), and novel invasive crayfish (Pacifastacus leniusculus). G. pulex responded differently to fish and crayfish; showing enhanced locomotion in response to fish, but a preference for the dark over the light in response to the crayfish. P. jenkinsi showed increased vertical migration in response to all three predator cues relative to controls. These different responses to fish and crayfish are hypothesised to reflect the predators’ differing predation types; benthic for crayfish and pelagic for fish. However, we found no difference in response to native versus invasive crayfish, indicating that prey naiveté is unlikely to drive the impacts of invasive crayfish. The Predator Recognition Continuum Hypothesis proposes that benefits of generalisable predator recognition outweigh costs when predators are diverse. Generalised responses of prey as observed here will be adaptive in the presence of an invader, and may reduce novel predators’ potential impacts

Legal and institutional arrangements for urban sanitation and hygiene in Bhutan

This review explores the legal and institutional frameworks guiding urban sanitation and hygiene in Bhutan. It was commissioned in April 2012 to inform the Sustainable Sanitation and Hygiene for All in Small Towns (SSH4A in Small Towns) programme being undertaken by SNV Bhutan and the Ministry of Works and Human Settlements (MoWHS). This review is the product of a desktop review and consultations with key informants to assess the policy, legal and institutional arrangements for urban sanitation and hygiene in Bhutan, with a particular focus on situation in smaller urban centres

Damping Control in Power Systems Under Constrained Communication Bandwidth: A Predictor Corrector Strategy

Damping electromechanical oscillations in power systems using feedback signals from remote sensors is likely to be affected by occasional low bandwidth availability due to increasing use of shared communication in future. In this paper, a predictor corrector (PC) strategy is applied to deal with situations of low-feedback data rate (bandwidth), where conventional feedback (CF) would suffer. Knowledge of nominal system dynamics is used to approximate (predict) the actual system behavior during intervals when data from remote sensors are not available. Recent samples of the states from a reduced observer at the remote location are used to periodically reset (correct) the nominal dynamics. The closed-loop performance deteriorates as the actual operating condition drifts away from the nominal dynamics. Nonetheless, significantly better performance compared to CF is obtained under low-bandwidth situations. The analytical criterion for closed-loop stability of the overall system is validated through a simulation study. It is demonstrated that even for reasonably low data rates the closed-loop stability is usually ensured for a typical power system application confirming the effectiveness of this approach. The deterioration in performance is also quantified in terms of the difference between the nominal and off-nominal dynamics

The challenges of change:Exploring the dynamics of police reform in Scotland

Despite a long tradition of pessimism regarding the scope for meaningful change in police practices, recent structural reforms to police organizations in several European countries suggest that significant change in policing is possible. Drawing on recent research into the establishment and consequences of a national police force in Scotland, this article uses instrumental, cultural and myth perspectives taken from organization theory to examine how change happened and with what effects. It highlights how police reform involves a complex interplay between the strategic aims of government, the cultural norms of police organizations and the importance of alignment with wider views about the nature of the public sector. The article concludes by identifying a set of wider lessons from the experience of organizational change in policing