194 research outputs found
Climate and soil microâorganisms drive soil phosphorus fractions in coastal dune systems
1. The importance of soil phosphorus (P) is likely to increase in coming decades due to the growing atmospheric nitrogen (N) deposition originated by industrial and agricultural activities. We currently lack a proper understanding of the main drivers of soil P pools in coastal dunes, which rank among the most valued priority conservation areas worldwide. 2. Here, we evaluated the joint effects of biotic (i.e. microbial abundance and richness, vegetation and cryptogams cover) and abiotic (i.e. pH and aridity) factors on labile, mediumâlability and recalcitrant soil P pools across a wide aridity gradient in the Atlantic coast of the Iberian Peninsula. 3. Climate determined the availability of mediumâlability, recalcitrant and total P, but had a minor net effect on labile P, which was positively and significantly related to the presence of plants, mosses and lichens. Mediumâlability P was significantly influenced by soil bacterial richness and abundance (positively and negatively, respectively). 4. Our results suggest that microâorganisms transfer P from mediumâlability pool to more labile one. At the same time, increases in bacterial richness associated to biofilms might be involved in the thickening of the mediumâlability P pool in our climosequence. 5. These bacterialâmediated transfers would confer resistance to the labile P pool under future climate change and uncover an important role of soil microâorganisms as modulators of the geochemical P cycle.This project was financed by FEDER/Ministerio de Ciencia, InnovaciĂłn y Universidades-Agencia Estatal de InvestigaciĂłn/Proyect (CGL2017-88124-R), European Research Council (ERC Grant Agreement 647038 [BIODESERT]) and the Fundaçã o para CiĂȘncia e Tecnologia (IF/00950/2014) and the FEDER, within the PT2020 Partnership Agreement and COMPETE 2020 (UID/BIA/04004/2013). F.T.M. acknowledges support from Generalitat Valenciana (CIDEGENT/2018/041). B.K.S. acknowledge research support on microbes and ecosystem functions from the Australian Research Council (DP170104634) and Research Award from the Humboldt Foundation
Exploring the relationship between media coverage and participation in entrepreneurship : initial global evidence and research implications
Using a set of variables measured in the Global Entrepreneurship Monitor (GEM) study, our empirical investigation explored the influence of mass media through national culture on national entrepreneurial participation rates in 37 countries over 4 years (2000 to 2003). We found that stories about successful entrepreneurs, conveyed in mass media, were not significantly associated with the rate of nascent (opportunity searching) or the rate of actual (business activities commenced up to 3 months old) start-up activity, but that there was a significant positive association between the volume of entrepreneurship media stories and a nation’s volume of people running a young business (that is in GEM terminology, a business aged greater than 3 but less than 42 months old). More particularly, such stories had strong positive association with opportunity oriented operators of young businesses. Together, these findings are compatible with what in the mass communications theory literature may be called the ‘reinforcement model’. This argues that mass media are only capable of reinforcing their audience’s existing values and choice propensities but are not capable of shaping or changing those values and choices. In the area covered by this paper, policy-makers are committing public resources to media campaigns of doubtful utility in the absence of an evidence base. A main implication drawn from this study is the need for further and more sophisticated investigation into the relationship between media coverage of entrepreneurship, national culture and the rates and nature of people’s participation in the various stages of the entrepreneurial process.<br /
Analysis of subcellular metabolite levels of potato tubers (Solanum tuberosum) displaying alterations in cellular or extracellular sucrose metabolism
The expression of a heterologous invertase in potato tubers (Solanum tuberosum) in either the cytosol or apoplast leads to a decrease in total sucrose content and to an increase in glucose. Depending on the targeting of the enzyme different changes in phenotype and metabolism of the tubers occur: the cytosolic invertase expressing tubers show an increase in the glycolytic flux, accumulation of amino acids and organic acids, and the appearance of novel disaccharides; however, these changes are not observed when the enzyme is expressed in the apoplast [Roessner et al. (2001). Plant Cell, 13, 11-29]. The analysis of these lines raised several questions concerning the regulation of compartmentation of metabolites in potato tubers. In the current study we addressed these questions by performing comparative subcellular metabolite profiling. We demonstrate that: (i) hexoses accumulate in the vacuole independently of their site of production, but that the cytosolic invertase expression led to a strong increase in the cytosolic glucose concentration and decrease in cytosolic sucrose, whereas these effects were more moderate in the apoplastic expressors; (ii) three out of four of the novel compounds found in the cytosolic overexpressors accumulate in the same compartment; (iii) despite changes in absolute cellular content the subcellular distribution of amino acids was invariant in the invertase overexpressing tubers. These results are discussed in the context of current models of the compartmentation of primary metabolism in heterotrophic plant tissues
Dynamics of soil organic carbon following land-use change: insights from stable C-isotope analysis in black soil of Northeast China
Intensive soil tillage is a significant factor in soil organic matter decline in cultivated soils. Both cultivation abandonment and foregoing tillage have been encouraged in the past 30 years to reduce greenhouse gas emissions and soil erosion. However, the dynamic processes of soil organic carbon (SOC) in areas of either continuous cultivation or abandonment remain unclear and inconsistent. Our aims were to assess and model the dynamic processes of SOC under continuous tillage and after cultivation abandonment in the black soil of Northeast China. Soil profiles were collected of cultivated or abandoned land with cultivation history of 0â100 years. An isotope mass balance equation was used to calculate the proportion of SOC derived from corn debris (C4) and from natural vegetation (C3) to deduce the dynamic process. Approximately 40% of SOC in the natural surface soil (0â10 cm) was eroded in the first 5 years of cultivation, increasing to about 75% within 40 years, before a slow recovery. C4 above 30 cm soil depth increased by 4.5%â5% or 0.11â0.12 g·kgâ1 on average per year under continuous cultivation, while it decreased by approximately 0.34% annually in the surface soil after cultivation abandonment. The increase in the percentage of C4 was fitted to a linear equation with given intercepts in the upper 30 cm of soil in cultivated land. A significant relationship between the change of C4 and time was found only in the surface soil after abandonment of cultivation. These results demonstrate the loss and accumulation of corn-derived SOC in surface black soil of Northeast China under continuous tillage or cultivation abandonment
Public health research systems in the European union
<p>Abstract</p> <p>Background</p> <p>Strengthening health research is an important objective for international health organisations, but there has been less attention to support for health research in Europe. We describe the public-health (population and organisational level) research systems in the 27 European Union countries.</p> <p>Methods</p> <p>We developed a typology for describing health research structures based on funding streams and strategies. We drew data from internet sources and asked country informants to review these for consistency and completeness. The structures were described as organograms and narratives in country profiles for each of the 27 EU member states. National public-health research structures included public and independent funding organisations, 'mixed' institutions (which receive funds, and both use and allocate them) and provider institutions.</p> <p>Results</p> <p>Most health research is funded through ministries of science or science councils (and sometimes foundations), while parliaments and regions may also contribute. National institutes of public health are usually funded by ministries of health. Many national research organisations both determine research programmes and undertake health research, but there is a move towards public-health sciences within the universities, and a transition from internal grants to competitive funding. Of 27 national research strategies, 17 referred to health and 11 to public health themes. Although all countries had strategies for public health itself, we found little coherence in public-health research programmes. The European Commission has country contact points for both EU research and health programmes, but they do not coordinate with national health-research programmes.</p> <p>Conclusions</p> <p>Public-health research is broadly distributed across programmes in EU countries. Better understanding of research structures, programmes and results would improve recognition for public health in Europe, and contribute to practice. EU ministries of health should give greater attention to national public-health research strategies and programmes, and the European Union and the World Health Organisation can provide coordination and support.</p
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Diversity in Expression of Phosphorus (P) Responsive Genes in Cucumis melo L
Phosphorus (P) is a major limiting nutrient for plant growth in many soils. Studies in model species have identified genes involved in plant adaptations to low soil P availability. However, little information is available on the genetic bases of these adaptations in vegetable crops. In this respect, sequence data for melon now makes it possible to identify melon orthologues of candidate P responsive genes, and the expression of these genes can be used to explain the diversity in the root system adaptation to low P availability, recently observed in this species
Connectivity of larval stages of sedentary marine communities between hard substrates and offshore structures in the North Sea
Man-made structures including rigs, pipelines, cables, renewable energy devices, and ship wrecks, offer hard substrate in the largely soft-sediment environment of the North Sea. These structures become colonised by sedentary organisms and non-migratory reef fish, and form local ecosystems that attract larger predators including seals, birds, and fish. It is possible that these structures form a system of interconnected reef environments through the planktonic dispersal of the pelagic stages of organisms by ocean currents. Changes to the overall arrangement of hard substrate areas through removal or addition of individual man-made structures will affect the interconnectivity and could impact on the ecosystem. Here, we assessed the connectivity of sectors with oil and gas structures, wind farms, wrecks, and natural hard substrate, using a model that simulates the drift of planktonic stages of seven organisms with sedentary adult stages associated with hard substrate, applied to the period 2001â2010. Connectivity was assessed using a classification system designed to address the function of sectors in the network. Results showed a relatively stable overall spatial distribution of sector function but with distinct variations between species and years. The results are discussed in the context of decommissioning of oil and gas infrastructure in the North Sea
Nitrogen and Carbon Isotopic Dynamics of Subarctic Soils and Plants in Southern Yukon Territory and its Implications for Paleoecological and Paleodietary Studies
We examine here the carbon and nitrogen isotopic compositions of bulk soils (8 topsoil and 7 subsoils, including two soil profiles) and five different plant parts of 79 C3 plants from two main functional groups: herbs and shrubs/subshrubs, from 18 different locations in grasslands of southern Yukon Territory, Canada (eastern shoreline of Kluane Lake and Whitehorse area). The Kluane Lake region in particular has been identified previously as an analogue for Late Pleistocene eastern Beringia. All topsoils have higher average total nitrogen ÎŽ15N and organic carbon ÎŽ13C than plants from the same sites with a positive shift occurring with depth in two soil profiles analyzed. All plants analyzed have an average whole plant ÎŽ13C of â27.5 ± 1.2 â° and foliar ÎŽ13C of ±28.0 ± 1.3 â°, and average whole plant ÎŽ15N of â0.3 ± 2.2 â° and foliar ÎŽ15N of ±0.6 ± 2.7 â°. Plants analyzed here showed relatively smaller variability in ÎŽ13C than ÎŽ15N. Their average ÎŽ13C after suitable corrections for the Suess effect should be suitable as baseline for interpreting diets of Late Pleistocene herbivores that lived in eastern Beringia. Water availability, nitrogen availability, spacial differences and intra-plant variability are important controls on ÎŽ15N of herbaceous plants in the study area. The wider range of ÎŽ15N, the more numerous factors that affect nitrogen isotopic composition and their likely differences in the past, however, limit use of the modern N isotopic baseline for vegetation in paleodietary models for such ecosystems. That said, the positive correlation between foliar ÎŽ15N and N content shown for the modern plants could support use of plant ÎŽ15N as an index for plant N content and therefore forage quality. The modern N isotopic baseline cannot be applied directly to the past, but it is prerequisite to future efforts to detect shifts in N cycling and forage quality since the Late Pleistocene through comparison with fossil plants from the same region
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