Prey preference of lingcod (Ophiodon elongatus), a top marine predator: implications for ecosystem-based fisheries management

Many highly exploited ecosystems are managed on the basis of single-species demographic information. This management approach can exacerbate tensions among stakeholders with competing interests who in turn rely on data with notoriously high variance. In this case study, an application of diet and dive survey data was used to describe the prey preference of lingcod (Ophiodon elongatus) in a predictive framework on nearshore reefs off Oregon. The lingcod is a large, fast-growing generalist predator of invertebrates and fishes. In response to concerns that lingcod may significantly reduce diminished populations of rockfishes (Sebastes spp.), the diets of 375 lingcod on nearshore reefs along the Oregon Coast were compared with estimates of relative prey availability from dive surveys. In contrast to the transient pelagic fishes that comprised 46% of lingcod diet by number, rockfishes comprised at most 4.7% of prey items. Rockfishes were the most abundant potential prey observed in dive surveys, yet they were the least preferred. Ecosystem-based fisheries management (EBFM) requires information about primary trophic relationships, as well as relative abundance and distribution data for multiple species. This study shows that, at a minimum, predation relative to prey availability must be considered before predator effects can be understood in a management context

A Critical Review of Ian Barbour's Analysis of Discussions on the Mind/Body Problem

The concepts of mind, soul, and consciousness are key to an understanding of ourselves and how we interact with the universe around us. Ian Barbour names the mind/body problem as one of the major subjects of long-term discussion among religion, philosophy, and science, including cognitive psychology. However, his treatment of the traditional philosophical positions on this topic is wanting. What is most intriguing is that, after years of discussion, newer approaches to the mind/body problem seem to have come full circle, sharing many commonalities with the much older approach of property dualism

Homology of holomorphs of free groups

The holomorph of a free group $F_n$ is the semidirect product $F_n \rtimes Aut(F_n)$. Using the methods of Hatcher and Vogtmann, we derive stability results and calculate the mod-$p$ homology of these holomorphs for odd primes $p$ in dimensions 1 and 2, and their rational homology in dimensions 1 through 5. Calculations of the twisted (where $Aut(F_n)$ acts by first projecting to $Gl_n(\Z)$ and then including in Gl_n(\Q)) homology H_*(Aut(F_n); \Q^n) follow in corresponding dimensions.Comment: Revised using helpful comments of referee. Accepted by J. Algebra. J. Algebra has agreed to host the Maple program files (currently on my web page) on their sit

Classroom-based action research: revisiting the process as customizable and meaningful professional development for educators

The approach historically used for professional development for classroom educators (i.e., a 'one-size-fits-all' delivery model, where the emphasis is on 'training' and not on 'learning') is, quite simply, outdated. Even in our 'on-demand' world, where professional development modules can be purchased and viewed online, the individualized professional development needs of teachers are not appropriately or accurately being met. Classroom-based action research—with its cyclical nature of systematic investigation of teaching and learning, followed by data-driven improvements resulting from the outcomes of the investigations—provides not only a viable, but also valuable, professional development alternative. Following the development of improvement goals, the process of action research can be used to customize a teacher's professional development, allowing for a much more meaningful approach to professional growth. This approach permits teachers to investigate their own practice and to discover what will and will not work for their students in their classrooms. The integration of classroom-based action research with professional collaboration and with teacher evaluation are both discussed. Recommendations for administrative support—focusing on training, availability of time, collaboration, and incentives—for classroom-based action research are also provided

Observation of the Final Boundary Condition: Extragalactic Background Radiation and the Time symmetry of the Universe

This paper examines an observable consequence for the diffuse extragalactic background radiation (EGBR) of the hypothesis that if closed, our universe possesses time symmetric boundary conditions. For simplicity, attention is focused on optical wavelengths. The universe is modeled as closed Friedmann- Roberston-Walker. It is shown that, over a wide range of frequencies, electromagnetic radiation can propagate largely unabsorbed from the present epoch into the recollapsing phase, confirming and demonstrating the generality of results of Davies and Twamley. As a consequence, time symmetric boundary conditions imply that the optical EGBR is at least twice that due to the galaxies on our past light cone, and possibly considerably more. It is therefore possible to test experimentally the notion that if our universe is closed, it may be in a certain sense time symmetric. The lower bound on the "excess" EGBR in a time symmetric universe is consistent with present observations. Nevertheless, better observations and modelling may soon rule it out entirely. In addition, many physical complications arise in attempting to reconcile a transparent future light cone with time symmetric boundary conditions, thereby providing further arguments against the possibility that our universe is time symmetric.Comment: latex 2.09, 30 pages, 1 figure. Figure added, errors corrected. Slight revision of published versio