Management of Multipurpose Heterogeneous Fishing Fleets Under Uncertainty

This paper describes an approach to modeling fisheries that can be useful in policy analysis when the population dynamics are not well known and the fleet is composed of a variety of multipurpose vessels. An empirical application of the methodology to the northern California Dungeness crab fishery is discussed. A multivariate time-series model provides the intertemporal (year-to-year) relationships for a simulation model describing both within season and year-to-year fleet behavior. Appropriate modifications of the simulation model parameters reflect alternative policy scenarios. The analysis of the simulation outcomes provide insight into fleet response to several management alternatives that have been considered for the crab fishery.Environmental Economics and Policy, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy, Risk and Uncertainty,

MECHANISMS FOR ADDRESSING THIRD-PARTY IMPACTS RESULTING FROM VOLUNTARY WATER TRANSFERS

This research uses laboratory experiments to test alternative water market institutions designed to protect third-party interests. The institutions tested include taxing mechanisms that raise revenue to compensate affected third-parties, and a free market in which third-parties actively participate. We also discuss the likely implications of a command-and-control approach in which there are fixed limits on the volume of water that may be exported from a region. The results indicate that there are some important trade-offs in selecting a policy option. Although theoretically optimal, active third-party participation in the market is likely to result in free-riding that may erode some or all of the efficiency gains, and may introduce volatility into the market. Fixed limits on water exports are likely to result in a more stable market, but the constraints on exports will result in lower levels of social welfare. Taxing transfers and compensating third-parties offers a promising balance of efficiency, equity and market stability.Resource /Energy Economics and Policy,

The effects of entry on incumbent innovation and productivity

How does firm entry affect innovation incentives in incumbent firms? Microdata suggest that there is heterogeneity across industries. Specifically, incumbent productivity growth and patenting is positively correlated with lagged greenfield foreign firm entry in technologically advanced industries, but not in laggard industries. In this paper we provide evidence that these correlations arise from a causal effect predicted by Schumpeterian growth theory—the threat of technologically advanced entry spurs innovation incentives in sectors close to the technology frontier, where successful innovation allows incumbents to survive the threat, but discourages innovation in laggard sectors, where the threat reduces incumbents' expected rents from innovating. We find that the empirical patterns hold using rich micro panel data for the United Kingdom. We control for the endogeneity of entry by exploiting major European and U.K. policy reforms, and allow for endogeneity of additional factors. We complement the analysis for foreign entry with evidence for domestic entry and entry through imports

Motivational orientation and risk taking in elite winter climbers: A qualitative study

Objectives: High risk sports participants have typically been viewed as a homogenous group despite variability in performance characteristics and the level of risk undertaken. Prolonged engagement high risk sports such as winter climbing are relatively underserved within current literature. Elite winter climbers attempt climbs that are outside the scope of the current ‘known’ i.e. unclimbed routes. The majority of the current understanding of motivation in high risk sports is based on quantitative research and the methodologies and instruments used. The purpose of this study was to explore the experiences of elite winter climbers and gain a richer understanding of their motivational orientation and risk taking behaviour. Design: Qualitative – inductive. Method: Four elite male winter climbers (aged 42-49 years old) took part in semi-structured interviews and explore their motivational orientation and risk taking behaviour. A thematic analysis was used. Results: Two super-ordinate themes of enactive mastery and engendered disinhibition emerged from the data. Enactive mastery was interpreted as a composite of two higher order themes; task mastery and self-mastery. Engendered disinhibition was interpreted as a composite of two higher order themes; social cognitive appraisal and self-perception. Conclusion: Enactive mastery and engendered disinhibition emerged as key behavioural and psychological determinants that influenced individuals to attempt more difficult and riskier forms of winter climbing. Goal achievement was their primary motive which was set within a confidence frame encapsulated within these super-ordinate themes

Contextual factors among indiscriminate or larger attacks on food or water supplies, 1946-2015

This research updates previous inventories of malicious attacks on food and water to include data from 1946 through mid-2015. A systematic search of news reports, databases and previous inventories of poisoning events was undertaken. Incidents that threatened or were intended to achieve direct harm to humans, and that were either relatively large (number of victims > 4 or indiscriminate in intent or realisation were included. Agents could be chemical, biological or radio-nuclear. Reports of candidate incidents were subjected to systematic inclusion and exclusion criteria as well as validity analysis (not always clearly undertaken in previous inventories of such attacks). We summarise contextual aspects of the attacks that may be important for scenario prioritisation, modelling and defensive preparedness. Opportunity is key to most realised attacks, particularly access to dangerous agents. The most common motives and relative success rate in causing harm were very different between food and water attacks. The likelihood that people were made ill or died also varied by food/water mode, and according to motive and opportunity for delivery of the hazardous agent. Deaths and illness associated with attacks during food manufacture and prior to sale have been fewer than those in some other contexts. Valuable opportunities for food defence improvements are identified in other contexts, especially food prepared in private or community settings

Common-Envelope Episodes that lead to Double Neutron Star formation

Close double neutron stars have been observed as Galactic radio pulsars, while their mergers have been detected as gamma-ray bursts and gravitational-wave sources. They are believed to have experienced at least one common-envelope episode during their evolution prior to double neutron star formation. In the last decades there have been numerous efforts to understand the details of the common-envelope phase, but its computational modelling remains challenging. We present and discuss the properties of the donor and the binary at the onset of the Roche-lobe overflow leading to these common-envelope episodes as predicted by rapid binary population synthesis models. These properties can be used as initial conditions for detailed simulations of the common-envelope phase. There are three distinctive populations, classified by the evolutionary stage of the donor at the moment of the onset of the Roche-lobe overflow: giant donors with fully-convective envelopes, cool donors with partially-convective envelopes, and hot donors with radiative envelopes. We also estimate that, for standard assumptions, tides would not circularise a large fraction of these systems by the onset of Roche-lobe overflow. This makes the study and understanding of eccentric mass-transferring systems relevant for double neutron star populations.Comment: 26 pages, 10 figures. Includes bug fix. Two new figures and an appendix adde

Determining adrenocortical activity as a measure of stress in African buffalo (Syncerus caffer) based on faecal analysis

Little is known about the levels of stress experienced by African buffalos affected by injury, disease, or socio-ecological and anthropogenic factors. To be able to start filling this gap, we examined the suitability of two 11-oxoaetiocholanolone enzyme-immunoassays (EIAs) detecting 11,17 dioxoandrostanes (11,17-DOA) as well as faecal glucocorticoid metabolites (FGMs) with a 5β-3α-ol-11-one structure (3α,11oxo-CM), respectively, for monitoring stress-related physiological responses in African buffalo. An adrenocorticotrophic hormone (ACTH) challenge in one male and one female housed at Mokopane Biodiversity Conservation Centre, South Africa, showed a threefold increase in circulating cortisol levels in a sample taken 40 min post-injection. Corresponding 11,17-DOA levels increased tenfold (female) and 15-fold (male) above baseline, and 3α,11oxo-CM concentrations increased ninefold (female) and 12-fold (male) above pre-injection levels, indicating that both EIAs are suitable for measuring FGMs in African buffalo.In addition, 11,17-DOA levels monitored during the adaptation process of individual housing revealed an up to 14-fold elevation in FGMs. Storage of faeces at ambient temperature for up to 16 h post-defecation resulted in an significant increase in 11,17-DOA levels 2 h after defecation. Finally, higher individual baseline 11,17-DOA concentrations were found in samples defecated overnight, indicating a possible diurnal effect in excretion of FGMs in African buffalo.http://africanzoology.journals.ac.za/am2013ab201