Rebuilding the Eastern Baltic cod stock under environmental change - a preliminary approach using stock, environmental, and management constraints

The population dynamics of the Eastern Baltic cod (Gadus morhua callarias L.), unlike many other stocks, shows a strong dependency on environmental conditions. To test the implications of different management policies on the stock and the fishery in a system of global environmental change, we apply a spatially disaggregated, discrete time, age-structured model of the Eastern Baltic cod stock in 50 year simulation analyses. The simulation provides an analysis of stock, yield, and revenue development under various management policies and environmental scenarios. The policy analysis, focusing on different regulations of fishing mortality, is embedded into three environmental scenarios, assuming low, medium, or high climate and environmental change. The environmental assumptions are based on simulation results from a coupled atmosphere-ocean regional climate model, which project salinity in the Baltic Sea to decrease by 7-47% in the period 2071-2100 relative to the reference period 1961-1990. Our simulation results show that a significant reduction in fishing mortality is necessary for achieving high long-term economic yields. Moreover, under the presented environmental scenarios, a stock collapse cannot be prevented. It can, however, be postponed by the establishment of a marine reserve in ICES subdivision 25.Baltic cod, climate change, environmental variability, reproductive volume, population dynamics, management, policy, age-structured model, temporal marine reserve

Rebuilding the Eastern Baltic cod stock under environmental change - Part II: The economic viability of a marine protected area

This study adds a cost analysis of the Eastern Baltic cod fishery to the existing model presented in Röckmann et al. (forthcoming). As cost data on this international fishery do not exist, available data from Denmark are extrapolated to the whole international fishery. Additionally, unit and total variable costs are simulated and the sensitivity to a set of different cost-stock and cost-output elasticities is tested. The study supports preliminary conclusions that a temporary marine reserve policy, which focuses on protecting the Eastern Baltic cod spawning stock in ICES subdivision 25, is a valuable fisheries management tool to (a) rebuild the overexploited Eastern Baltic cod stock and (b) increase operating profits. The negative effects of climate change can be postponed for at least 20 years – depending on the assumed rate of future climate change. Including costs in the economic analysis does not change the ranking of management policies as proposed in the previous study where costs were neglected.Development, Baltic cod, cost-stock elasticity, cost-output elasticity, sensitivity analysis, climate change scenario, management, policy, temporal marine reserve

Fluorescence and phosphorescence from individual C60_{60} molecules excited by local electron tunneling

Using the highly localized current of electrons tunneling through a double barrier Scanning Tunneling Microscope (STM) junction, we excite luminescence from a selected C$_{60}$ molecule in the surface layer of fullerene nanocrystals grown on an ultrathin NaCl film on Au(111). In the observed luminescence fluorescence and phosphorescence spectra, pure electronic as well as vibronically induced transitions of an individual C$_{60}$ molecule are identified, leading to unambiguous chemical recognition on the single-molecular scale

Word Problems in the Mathematics Textbook: An Instructional Resource Guide to support writing instruction.

Abstract Mathematics textbooks typically include word problems or story problems that require students to develop extended written responses. Yet, the answers to these prompts can vary so widely that preservice and inservice teachers must be prepared for multiple levels of interpretation of the language used to capture mathematical thinking. Based on an analysis of word problems within two teacher’s editions of elementary mathematics textbooks, we describe a series of strategies and tasks to scaffold teachers’ understanding of planning for word problems during mathematics instruction. We detail the following components; (1) the use of the Instructional Resource Guide, which assists in the decision-making process to support preservice and inservice teachers as they plan and analyze word problem language aiding in the selection of tasks based on specific objectives or instructional goals; (2) the creation of a consistent instructional sequence for integrated literacy instruction during mathematics instruction

Mehrsprachige Jugendliche im Umgang mit Dialekt und Hochsprache in der Deutschen Schweiz

For much too long the study of plurilingual pupils has been focussed on their deficits. In the present study special resources of underprivileged adolescents who are successful in their literal socialization were investigated. From a sample of 1500 15-year-olds 76 were asked to fulfil a writing task measuring their functional-pragmatic writing abilities. The results show only minor differences between mono- and plurilingual adolescents. The same trend can be detected for reading abilities as well, especially when empathic reading competence is included and socio-economic status is controlled for. The authors argue in favour of a concept for reading and writing which, in addition to traditional hard criteria like orthography and grammar for writing or information processing for reading, incorporates soft dimensions like emotional involvement (for reading) or communicative strategies (for writing). Reading and writing socialization viewed in such terms can only succeed if schools find ways to embed reading and writing in their students' lives in a way which is perceived by them as meaningful

Testing the implications of a permanent or seasonal marine reserve on the population dynamics of Eastern Baltic cod under varying environmental conditions

In order to test the implications of the establishment of a marine reserve in the Baltic Sea, a spatially disaggregated, discrete time, age-structured model for the Eastern Baltic cod (Gadus morhua callarias L.) stock was constructed. Functional relationships for recruitment and predation mortality were developed by multiple regression analyses. The resultant model output compares well with observed data from the fishery. The model was then applied to simulate stock development over a 50 year time period using different management policies and a variety of environmental conditions. The investigated management policies reduce fishing mortality and range from a moratorium on the Eastern Baltic cod fishery via the establishment of a permanent or a seasonal marine reserve in ICES subdivision 25 to a fishing as usual scenario. The environmental conditions incorporated were based on the size of the reproductive volume (RV) and comprise a best case and a worst case of reproductive conditions, and two more realistic scenarios, where we assumed that a historic series of RV-sizes reoccurs over the simulation period. Our results show a strong dependence of stock dynamics on the environmental conditions. Under prevailing low RV, our model projects stock extinction by the year 2020, if fishing continues as usual. Under the restrictive scenarios, where fishing mortality is reduced either directly or by implementation of a marine reserve, the stock benefits from an increase in stock size and an improved age-structure. A seasonal closure of SD 25 as opposed to a closure of the entire Baltic Sea appears to be sufficient to prevent the Eastern Baltic cod stock from falling below safe biological limits.Baltic cod, management, age-structured model, population dynamics, MPA, environmental variability, reproductive volume

Long-term performance of organic crop rotations in the tropics: First results from a high and a medium potential site in sub-humid Central Kenya

Organic Agriculture is perceived by many stakeholders as a promising approach to increase food security in developing countries. However, only few attempts have been made so far to assess agronomic and economic performance of Organic Agriculture in these regions in a systematic way. The Research Institute of Organic Agriculture (FiBL), together with its partners, is presently establishing long-term comparisons of farming systems in various agro-ecological and socio-economic contexts to study the different parameters that are essential for sustainable development. To date, three study areas have been selected: (a) a sub-humid area in Kenya where farming is subsistence-oriented; (b) a semi-arid area in India where cotton is produced for the export market; and (c) a humid area in Bolivia where cacao and other perennial products are produced for the export and domestic markets. The key elements are replicated long-term field trials. These are complemented by farm surveys and short-term trials under on-farm conditions. This network of comparison of farming systems in the tropics is expected to (1) put the discussion on the benefits and drawbacks of Organic Agriculture on a rational basis; (2) help to identify challenges for Organic Agriculture that can then be addressed systematically; (3) provide physical reference points for stakeholders in agricultural research and development and thus support agricultural policy dialogue at different levels. In Kenya, the two trials sites are located in a high potential zone in Meru South District (Chuka) and in a medium potential zone in Maragua District (Thika). They consist of four treatments: conventional and organic, each at a low and a high input level, representing subsistence oriented and commercial farming, respectively. Maize, brassicas and maize were planted during the first, second and third season respectively in both organic and conventional plots. In the first three seasons, we found the following results: in Chuka, organic yields of the low input treatments were on average 4% lower than conventional yields. On the high input level, organic yields were 6% lower. In Thika, organic yields were on average 57% (low input level) and 33% (high input level) lower than conventional yields. It is assumed that the organic crops in Chuka could benefit from N and P mobilisation from the soil. In Thika, where N and P were probably less available, the crop depended on the easily soluble nutrients applied in the conventional treatments. The effect of lower nutrient availability in the organic treatments in Thika was possibly aggravated by serious drought spells during the second and third season. The questions of interest are a) whether the organic treatments can keep the yield level of the conventional treatments in Chuka or if they will go through a depression typical for conversion from conventional to Organic Agriculture; and b) if the organic treatments can improve soil fertility and thus the organic yield levels in Thika in the coming years

k-MED - from a local project to a service provider for eLearning

k-MED entwickelte sich von einem fachbezogenen Projekt im Jahr 1999 zu einem e-Learning-Dienstleister mit umfangreichen Lehr-Lernangeboten sowie einer technischen und organisatorischen Infrastruktur für Autoren und Nutzer. Es bietet heute – Mitte 2006 – 5000 Studierenden, v.a. der Humanmedizin, ca. 170 Lernkurse aus 16 medizinischen Fächern. Das Projekt umfasst erfahrenes Fachpersonal und nutzt eine eigene Online-Autorenumgebung sowie eine internetbasierte Lernplattform, deren Funktionalitäten in Abstimmung mit evaluierten Lehr- und Lern-Szenarien ständig weiter entwickelt werden. Die wichtigste Aufgabe ist die Vollversorgung von Bildungseinrichtungen, darunter vor allem medizinische Fakultäten, mit Lehr-Lern- und Kommunikationsinstrumenten. Aktuelle Informationen sind zu finden unter http://www.k-med.org.k-MED evolved from a single medical subject project in 1999 to a provider of comprehensive technology, infrastructure and content for authors and learners. It currently offers about 170 courses covering 16 medical subjects. The k-MED community consists of medical authors and experts for technology, graphical and instructional design. It has its proprietary authoring tools and an internet based learning management system, both being continually improved corresponding to service experiences. k-MED aims at ongoing development as a service provider for educational institutions for undergraduate or continuing medical education. For further information see http://www.k-med.org