124,713 research outputs found
Individual based modeling of North Atlantic common minke whale (Balaenoptera acutorostrata) migratory and foraging behaviour in the Nordic Seas
The North Atlantic common minke whale (Balaenoptera Acutorostrata) is an abundant, top-level marine predator in the Nordic Seas and Barents Sea ecosystems whose large-scale migratory and foraging behaviors are widely unknown. Understanding these behaviors may offer important insight into their life-history and management-unit structuring as defined by the International Whaling Commission. Existing modeling do not incorporate spatially-explicit movements of individual minkes, limiting our ability to investigate their large- scale behaviors. In this study, an individual based model (IBM) for minke whales is developed as an extension of the NORWECOM.E2E ecosystem model to identify behaviors that may contribute to minke distribution in the Nordic Seas. The energetic reward of both their use of migration within predominant currents and four large-scale foraging strategies are investigated. First, the effect on minke migration from ocean circulation and migration path selection are tested by running simulations with variation in activation of currents and paths (into and out of the Nordic Seas) along the Norwegian coast, the Norwegian Sea center, and the Greenland coast. Simulations are then run with variation in foraging strategies: random-walk, migration only, and periodic searching for maximum prey density with either random-walk or migration along the route determined to be optimal. NORWECOM.E2E model output of Norwegian spring-spawning herring, blue whiting, and mackerel are used as prey-fields. The optimal migration route is found to be in along the Norwegian coast and out through the Norwegian Sea center, with mean migration durations of 24.611 ± 0.051 d and 24.997 ± 0.041 d. Foraging that incorporates migration and 10 d periods of maximum prey density searching is found to have the highest foraging efficiency index (2.381 ± 0.435). Random- walk movement with maximum prey density searching had similarly high in- dex (2.256 ± 0.444), along with an increase in mean individual whale movement of 14.159 km d^_1 whale^_1 . The development of a minke IBM is an important addition of a high-level predator in Nordic Seas and Barents Sea modeling efforts, and the results from this study could have implications for minke population structuring and success in these areas. With migration throughout the Nordic Seas being energetically viable, interaction between whales categorized as separate sub-stocks could be possible. As an unvalidated model with key improvements necessary, further development of individual based modeling of minkes with more dynamic data is encouraged.JMAMN-MCLIMCLI39
Non-L\'evy mobility patterns of Mexican Me'Phaa peasants searching for fuelwood
We measured mobility patterns that describe walking trajectories of
individual Me'Phaa peasants searching and collecting fuelwood in the forests of
"La Monta\~na de Guerrero" in Mexico. These one-day excursions typically follow
a mixed pattern of nearly-constant steps when individuals displace from their
homes towards potential collecting sites and a mixed pattern of steps of
different lengths when actually searching for fallen wood in the forest.
Displacements in the searching phase seem not to be compatible with L\'evy
flights described by power-laws with optimal scaling exponents. These findings
however can be interpreted in the light of deterministic searching on heavily
degraded landscapes where the interaction of the individuals with their scarce
environment produces alternative searching strategies than the expected L\'evy
flights. These results have important implications for future management and
restoration of degraded forests and the improvement of the ecological services
they may provide to their inhabitants.Comment: 15 pages, 4 figures. First version submitted to Human Ecology. The
final publication will be available at http://www.springerlink.co
Improving Primo Usability and Teachability with Help from the Users
In the aftermath of a consortium migration to a shared cloud-based resource management and discovery system, a small college library implemented a web usability test to uncover the kinds of difficulties students had with the new interface. Lessons learned from this study led to targeted changes, which simplified aspects of searching, but also enhanced the librarians’ ability to teach more effectively. The authors discuss the testing methods, results, and teaching opportunities, both realized and potential, which arose from implementing changes
Job-search and FDI in a two-sector general equilibrium model
The purpose of this paper is to extend the Fields’ (1989) multi sector job-search model by introducing international trade and capital. Two types of capital are considered: fixed capital and mobile capital. The effects of search intensity and the inflow of foreign capital on the volume and the rate of urban unemployment and on the social welfare are also examined in both of the two cases. The main finding is: more efficient on-the-job search from the rural sector raises unemployment rate when capital is mobile between the two sectors. This is counterproductive to the standard result
HepData reloaded: reinventing the HEP data archive
We describe the status of the HepData database system, following a major
re-development in time for the advent of LHC data. The new HepData system
benefits from use of modern database and programming language technologies, as
well as a variety of high-quality tools for interfacing the data sources and
their presentation, primarily via the Web. The new back-end provides much more
flexible and semantic data representations than before, on which new external
applications can be built to respond to the data demands of the LHC
experimental era. The HepData re-development was largely motivated by a desire
to have a single source of reference data for Monte Carlo validation and tuning
tools, whose status and connection to HepData we also briefly review.Comment: 7 pages, 3 figures, Presented at 13th International Workshop on
Advanced Computing and Analysis Techniques in Physics Research (ACAT 2010),
February 22-27, 2010, Jaipur, Indi
Business as Usual: A Consumer Search Theory of Sticky Prices and Asymmetric Price Adjustment
Empirical evidence suggests that prices are sticky with respect to cost changes. Moreover, prices respond more rapidly to cost increases than to cost decreases. We develop a search theoretic model which is consistent with this evidence and allows for additional testable predictions. Our results are based on the assumption that buyers do not observe the sellers costs, but know that cost changes are positively correlated across sellers. In equilibrium, a change in price is likely to induce consumer search, which explains sticky prices. Moreover, the signal conveyed by a price decrease is different from the signal conveyed by a price increase, which explains asymmetry in price adjustment.
Immigrant Job Search in the UK
Most immigrant groups in the UK experience higher unemployment rates than otherwise similar UK born whites. Empirical research to date has attributed this finding to discrimination, lack of English Language fluency and the (non-) transferability of skills acquired before immigration. In this paper, we investigate how the job search methods of unemployed white and ethnic minority immigrants, and their success in exiting unemployment, compare with the UK born, using the panel element of the Quarterly Labour Force Survey, pooled over 1997-2001. We condition, amongst other things, on some observable immigrant characteristics and discuss the policy implications of our findings.unemployment, job search, immigrants
Digital information support for concept design
This paper outlines the issues in effective utilisation of digital resources in conceptual design. Access to appropriate information acts as stimuli and can lead to better substantiated concepts. This paper addresses the issues of presenting such information in a digital form for effective use, exploring digital libraries and groupware as relevant literature areas, and argues that improved integration of these two technologies is necessary to better support the concept generation task. The development of the LauLima learning environment and digital library is consequently outlined. Despite its attempts to integrate the designers' working space and digital resources, continuing issues in library utilisation and migration of information to design concepts are highlighted through a class study. In light of this, new models of interaction to increase information use are explored
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