Conditions for collective action: Understanding factors supporting and constraining community-based fish culture in Bangladesh, Cambodia and Vietnam

Flood-prone ecosystems in South and Southeast Asia are traditionally farmed with deepwater rice followed by post-flood rice culture during the dry season. During the flood season, the same land is inundated, creating an open-access water body subject to multiple uses by multiple users. Fish production in these areas is based on the capture of wild fish. In these seasonal flood plains, fish are trapped in rice fields, reproduce and are harvested by farmerfishers or full-time fishers. These flooded areas cover about 4.5 million hectares in Bangladesh, and 1.2-1.4 million hectares (Catling 1992) is deeply flooded in the Mekong Delta of Vietnam and Cambodia for 4 to 6 months each year. One option to improve access to protein and diversified income for local users and to improve water-use efficiency is to integrate fish culture into this system. A number of studies conducted in the 1980s tested the technical feasibility of culturing fish in seasonally flooded rice fields (Roy et al. 1990, Mukhopadhyay et al. 1992, Rothuis et al. 1998a, Rothuis et al. 1998b, Ali et al. 1998). These studies showed that fish production could be increased by more than 1 ton per hectare per year (t/ha/yr) by stocking fish in flooded rice fields in individual plots. Based on these findings, the WorldFish Center implemented between 1997 and 2000 on-farm experimental trials of community-based fish culture (CBFC) on the Ganges and Meghna floodplains of Bangladesh and the Red River and Mekong deltas in Vietnam (WorldFish 2002). Farms are cultivated individually during the dry season, but during the flood season individual landholding boundaries disappear under the water, and water bodies and flooded rice field resources become common property. The project was based on the premise that production from these water bodies could be enhanced by stocking locally important fish species, providing communities with an additional source of income and an increased supply of affordable fish for sale or consumption (e.g., Dey and Prein 2003, IIRR 2000, Sinhababu et al. 1984). The results showed that fish production can be increased, with an average of 226 kilograms (kg)/ha in Vietnam and 863 kg/ha in Bangladesh, with a significant improvement of the household income (Dey et al. 2005). CBFC was found technically and economically sound and socially acceptable. However, the project concluded that further research was needed to understand how the institutional mechanisms needed to support fish culture differ in a range of different contexts. From 2005 to 2010, the Challenge Program on Water and Food project Communitybased Fish Culture in Seasonal Floodplains developed a series of trials to test this technology under different environmental and socioeconomic conditions. The objective of the project was to test the feasibility of this approach to improve water-use efficiency and provide benefits to the various users of seasonally flooded rice fields. Technical and economic aspects were monitored, and locally appropriate group arrangements for fish culture management, benefit sharing and resource access were tested. Although the technical and environmental aspects of culture-based fisheries in various countries are well documented (De Silva 2003, Nguyen et al. 2001, De Silva etal. 2006), CBFC in seasonal floodplains is a relatively new concept, and the suitability of this approach in different contexts remains under question. The project aimed to address this issue by developing onfarm trials in seasonally flooding areas with otherwise contrasting socioeconomic and natural environments. In this report, we focus on a study designed to understand the factors and conditons that support or constrain the feasibility and uptake of community-based fish culture in seasonal floodplains. The aim of the study is to contribute to knowledge on institutions for collective action, and the feasibility of community-based approaches to resource management, based on lessons learned in this 5-year project. The study also offers useful lessons for project implementation in the field of research-for-development. The report begins with an introduction to the Community-based Fish Culture project and a description of the technical intervention. The second part of the report introduces the study to investigate the conditions for collective action in community-based fish culture, beginning with a presentation of the research approach and methodology. The third section presents the findings of the study. Finally, we present a synthesis of the factors supporing and constraining community-based fish culture, key lessons learned and recommendations

The habit-driven life: Accounting for inertia in departure time choices for commuting trips

This paper aims to explicitly account for the impact of inertia (or habit) on departure time decisions, and explore (1) to what extent departure time is influenced by inertia, (2) what influences individuals’ inertia with respect to departure time decisions, and (3) to what extent it impacts transport policies. We estimate an integrated choice and latent variable (ICLV) model using a stated preference survey for morning car commuters in the Greater Copenhagen Area. We interact the rescheduling components in the Scheduling Model (SM) with the latent variable Inertia. The modelling results show that higher levels of inertia yields higher rescheduling penalties and lower willing to shift departure time. Furthermore, we find that inertia in departure time is influenced by gender, presence of children in the household as well as work type. We test the behavioral responses to demand management policies for segments with different inertia, and find that the least inertial segment showed the highest substitution patterns, while the most inertial segment show the lowest substitution patterns. Finally, we compared the ICLV model to a reference model without inertia, and find that the effects of the demand management strategy is overestimated if inertia is neglected

Studies of the winter-time boundary layer over the Baltic Sea based on pilot balloon soundings

Sisältää myös toisen artikkelin: U. Larsson, L. Norling, S. Carlberg, S. Lööf, A. Tolstoy, K. von Bröckl, V. Elizarjeva, W. Kaiser, J. Lassig, I. Mäkinen, T. Melvasalo: Intercalibration of methods for cholorophyll measurements in the Baltic Se

Mixing height determination by ceilometer

International audienceA novel method for estimating the mixing height based on ceilometer measurements is described and tested against commonly used methods for determining mixing height. In this method an idealised backscatter profile is fitted to the observed backscatter profile. The mixing height is one of the idealised backscatter profile parameters. An extensive amount of ceilometer data and vertical soundings data from the Helsinki area in 2002 is utilized to test the applicability of the ceilometer for mixing height determination. The results, including 71 convective and 38 stable cases, show that in clear sky conditions the mixing heights determined from ceilometer based aerosol profiles and BL-height estimates based on sounding data are in a good agreement. Rejected outlier cases corresponded to very low aerosol concentrations in the mixed layer leading to a very weak aerosol backscatter signal in the lowest layer

Localized thinning for strain concentration in suspended germanium membranes and optical method for precise thickness measurement

We deposited Ge layers on (001) Si substrates by molecular beam epitaxy and used them to fabricate suspended membranes with high uniaxial tensile strain. We demonstrate a CMOS-compatible fabrication strategy to increase strain concentration and to eliminate the Ge buffer layer near the Ge/Si hetero-interface deposited at low temperature. This is achieved by a two-steps patterning and selective etching process. First, a bridge and neck shape is patterned in the Ge membrane, then the neck is thinned from both top and bottom sides. Uniaxial tensile strain values higher than 3% were measured by Raman scattering in a Ge membrane of 76 nm thickness. For the challenging thickness measurement on micrometer-size membranes suspended far away from the substrate a characterization method based on pump-and-probe reflectivity measurements was applied, using an asynchronous optical sampling technique.EC/FP7/628197/EU/Heat Propagation and Thermal Conductivity in Nanomaterials for Nanoscale Energy Management/HEATPRONAN