Thermogravimetry as a Method for Distinguishing Various Degrees of Mineralisation in Macromorphologically-defined Humus horizons

Horizons of typical forest humus forms were sampled using the morphological criteria for distinguishing horizons in the field as suggested by Babel (1972). These samples were investigated by thermogravimetric analysis. The resulting characteristic weight losses were associated with the biological components of the organic matrix (cellulose, hemicellulose, lignin). Statistical analysis of these weight losses correlated well with the morphological criteria, and difficulties in characterizing transitional forms in the field could be overcome by the application of thermogravimetric measurements. The present results suggest that thermogravimetry is a good method for the characterization of humus horizons.     

Farming systems approaches to international technical cooperation in agriculture and rural life

A farming systems approach to development has meant many things over the past 15 years, depending on its institutional and ecological setting, its target populations, and the goals motivating its implementation. Despite the diversity of approaches, and the sometimes rancorous discussion over which was best and why, the approach is now recognized in many places as the only one that can identify and respond to the needs of limited resource farm families, especially those in marginal ecosystems. Involving an iterative process of diagnosis, design, testing and extension, the farming system approach to date has done more to change research objectives at national and international institutions than to change actual farmer practices. By legitimizing what limited resource farmers do and why they do it, a farming systems approach lends itself to policy analysis as well. Recent research in farming systems suggests greater attention should be payed to exogenous variables, including policy and infrastructure, as well as to development of technology that really responds to the felt needs of limited resource farmers in improving their level of living.     

Access and control of resources: Lessons from the SANREM CRSP

Attention to differences within communities is important in working toward sustainability of an agro-ecosystem. In the Sustainable Agriculture and Natural Resource Management Collaborative Research Support Program, gender made a difference in terms of access and control over key resources – financial, human, natural, and social capital – critical for project success. Efforts to build social capital among women proved critical in developing both collective and households strategies for sustainability. The sites differed greatly in both landscape and lifescape. Women's position within each landscape provided an important perspective with which to assess and act toward achieving ecosystem, economic, and social sustainability. This revised version was published online in June 2006 with corrections to the Cover Date.     

Mutations in the DJ-1 gene associated with autosomal recessive early-onset parkinsonism

The DJ-1 gene encodes a ubiquitous, highly conserved protein. Here, we show that DJ-1 mutations are associated with PARK7, a monogenic form of human parkinsonism. The function of the DJ-1 protein remains unknown, but evidence suggests its involvement in the oxidative stress response. Our findings indicate that loss of DJ-1 function leads to neurodegeneration. Elucidating the physiological role of DJ-1 protein may promote understanding of the mechanisms of brain neuronal maintenance and pathogenesis of Parkinson's disease.     

Flowering and true seed production in potato (Solanum tuberosum L.). 2. Effects of stem density and pruning of lateral stems

Summary Field experiments were carried out to evaluate the effect of stem density and pruning of lateral stems on flowering and true seed production in potato (Solanum tuberosum L.). Increasing stem density reduced flowering, berry and seed production from every inflorescence in all cultivars. Increasing density increased the proportion of primary flowers in the total number of flowers per plant and reduced the proportion of flowers on lateral stems, but its effect on the quality of the seed production was small. Differences in total seed production were principally determined by differences in flowering. There was an interaction between stem density and cultivars for the number of flowers produced and on the yield of true seed per m². Pruning lateral stems enhanced flowering of the main stem and decreased the total number of flowers per plant, but it did not affect berry and seed production from main-stem inflorescences.     

The orbital period of the ultraluminous x-ray source in M82

The ultraluminous x-ray source (ULX) in the galaxy M82 has been identified as a possible intermediate-mass black hole formed in stellar collisions in the super star cluster MGG 11. The x-ray flux from M82 is modulated, with a peak-to-peak amplitude corresponding to an isotropic luminosity of 2.4 _ 1040 erg s-1 in M82 and a period of 62.0 +/- 2.5 days, which we interpret as the orbital period of the ULX binary. This orbital period implies that the mass-donor star must be a giant or supergiant. Large mass-transfer rates, sufficient to fuel the ULX, are expected for a giant-phase mass donor in an x-ray binary. The giant phase has a short lifetime, indicating that we see the ULX in M82 in a brief and unusual period of its evolution.     

Erratum to: Woody habitats promote pollinators and complexity of plant–pollinator interactions in homegardens located in rice terraces of the Philippine Cordilleras

Paddy and Water Environment -     

Growth,survival, and competitive ability of chestnut (<Emphasis Type="Italic">Castanea</Emphasis> Mill.) seedlings planted across a gradient of light levels

There has been an increased interest in tree breeding for resistance to exotic pests and pathogens, however relatively little research has focused on the reintroduction of these tree species. Understanding the durability of resistance in field settings and the field performance of improved trees is critical for successful species reintroduction. To evaluate methods for reintroducing American chestnut [Castanea dentata (Marsh.) Borkh] to managed forests on the Cumberland Plateau, we quantified four-year survival and growth and three-year competitive ability of chestnut seedlings planted on the Daniel Boone National Forest in southeastern Kentucky, USA. We used a split-plot design to compare chestnut response among three silvicultural treatments spanning a gradient of light levels; midstory removal, thinning, and shelterwood with reserves (2, 24, and 65% available photosynthetically active radiation, respectively) and three chestnut breeding types; American, Chinese (C. mollissima Blume.), and BC₂F₃ hybrid. One of two hybrid families planted had similar survival to American chestnuts, 21 and 27% survival, respectively, while the other had better survival, 57%. Chinese chestnut survival was better than the other breeding generations (90%). High mortality among American and hybrid chestnut seedlings was likely caused by infection from Phytophthora cinnamomi Rands. Incidence of blight infection was low. While chestnut seedling growth was greatest in the high-light treatment, competitive ability of chestnut, evaluated by comparing planted seedling height to height of understory competitors, was maximized in the intermediate light treatment. These results demonstrate the importance of evaluating competition pressure from co-occurring vegetation and field performance of resistant genotypes when assessing methods for reintroducing tree species to forested settings.