76 research outputs found
Genomic characterization and gene regulation optimization to further improve an enzymatic mix used as feed additive
A common indigestible fraction of cereal grains, representing a large part of poultry diet, is their content in non-starch polysaccharides (NSP). Talaromyces versatilis is a filamentous fungus presenting the capability to secrete a mixture of enzymes used as animal feed additive (Rovabio® Excel) to enhance hydrolysis of plant cell wall polysaccharides. When incorporated to feed, the nutrients are more efficiently digested leading to a decreased need in agricultural products and hence a more sustainable production of poultry meat. In this context, the genome of T. versatilis was sequenced and annotated with a focus on genes likely to encode glycoside hydrolases, transcription factors and proteins involved in the secretion pathway. We also undertook a genome-wide transcriptome analysis, of the fungus exposed to glucose or milled wheat straw (a complex lignocellulosic material), using RNA-seq. The data revealed that, incubated on glucose and then transferred to wheat straw, the mycellium expressed differentially 926 genes between the two conditions. The differential response in gene expression of key mutants such as △xlnR, △creA or △araR were analysed in order to study their roles in regulating transcription. This approach provides a global view of the network that regulates the expression of the glycoside hydrolyse-encoding genes. More specifically, XlnR was identified as the transcription factor controling expression of genes involved in arabinoxylan degradation. Within the variety of NSP, arabinoxylan is the prominent type for wheat and corn (around 50%). Despite being mainly composed of xylose (X) and arabinose (A), the A:X ratio are different between corn and wheat, with a higher value for corn and a higher proportion of substituted xyloses compared to wheat. Arabinofuranosidase activity enhancement is key to attack arabinoxylans with a high A:X ratio which are recalcitrant to breakdown by single xylanase activity. Therefore, we aimed at improving the Rovabio® Excel in order to improve its capacity to degrade highly branched arabinoxylans, by enriching it in arabinofuranosidases and xylanases. To address such a goal while keeping its enzymatic diversity, we over-expressed the XlnR transcription factor. As a result, we obtained a modified strain of Talaromyces versatilis with on optimized genetic regulation to secrete a higher amount of arabinoxylan degrading enzymes. The resulting product, named Rovabio® Advance, tested in broilers allowed restoring nutrient availability, and so growth performance, even with a nutrient content diluted by 3% compared to a control diet
Preface: Approaches and methods to improve risk management in volcanic areas
Active volcanoes can generate multiple types of
geological hazards. Besides syneruptive threats (e.g., lava,
pyroclastic flows or ash fall), other adverse events such as
landslides or lahars can occur at any time. To manage these
threats efficiently, three key objectives must be jointly addressed:
(1) improving prevention tools, through the collection
and acquisition of data on hazards and risks, and
its dissemination as maps and scenarios; (2) improving crisis
management capabilities, based on monitoring and early
warning systems, but also reliable communications systems;
and (3) reducing people’s vulnerability and developing recovery
and resilience capabilities after an event has occurred.
The special issue “Approaches and methods to improve
risk management in volcanic areas” presents research
results focusing on these three objectives. It demonstrates
the utility of addressing them jointly, and particularly examines
the case of volcanoes where little knowledge is available.
These results were presented at the conference Integrated
Approaches for Volcanic Risk Management (Hohenheim
University, Stuttgart, 11/12 September 2012) of the European
MIAVITA (MItigate and Assess risk from Volcanic
Impact on Terrain and human Activities) project
WebGIS as boundary tools between scientific geoinformation and disaster risk reduction action in volcanic areas
As the amount of spatial data is growing, there is increased interest in
developing tools to explore, visualize and interpret them, with the final
aim of informing decision making efficiently. Within the European MIAVITA
project, we examined this issue in the case of volcanic areas, where
existing geospatial databases are particularly complex due to the number of
threats to be considered, including volcanic (e.g. lava flows, ash fall)
and non-volcanic hazards, such as landslides or tsunamis. We involved a
group of hazard and risk analysts and managers, civil security officers, GIS
analysts and system developers to design a Web-based geographical
information system (WebGIS). We tested the system at the Mount Cameroon
volcano, taking advantage of a complex hazard and risk geographical
database. This study enabled identifying key requirements for such tools in
volcanic areas, such as the need to manage user privileges differently
according to their profile and the status of the volcano. This work also
highlights that, in addition to the development of large geoinformation
clearinghouses, there is a need for site-specific information systems
focused on working procedures of users, in order to fill the last gap
between data producers and users
A method for multi-hazard mapping in poorly known volcanic areas: an example from Kanlaon (Philippines)
Hazard mapping in poorly known volcanic areas is complex since much evidence of volcanic and non-volcanic hazards is often hidden by vegetation and alteration. In this paper, we propose a semi-quantitative method based on hazard event tree and multi-hazard map constructions developed in the frame of the FP7 MIAVITA project. We applied this method to the Kanlaon volcano (Philippines), which is characterized by poor geologic and historical records. We combine updated geological (long-term) and historical (short-term) data, building an event tree for the main types of hazardous events at Kanlaon and their potential frequencies. We then propose an updated multi-hazard map for Kanlaon, which may serve as a working base map in the case of future unrest. The obtained results extend the information already contained in previous volcanic hazard maps of Kanlaon, highlighting (i) an extensive, potentially active ~5 km long summit area striking north–south, (ii) new morphological features on the eastern flank of the volcano, prone to receiving volcanic products expanding from the summit, and (iii) important riverbeds that may potentially accumulate devastating mudflows. This preliminary study constitutes a basis that may help local civil defence authorities in making more informed land use planning decisions and in anticipating future risk/hazards at Kanlaon. This multi-hazard mapping method may also be applied to other poorly known active volcanoes
Climate change-driven coastal erosion modelling in temperate sandy beaches: Methods and uncertainty treatment
Developing future projections of shoreline change requires a good understanding of the driving coastal processes. These processes result primarily from the combination of mean sea level, waves, storm surges and tides, which are affected by global and regional climate change, and whose uncertainty increases with time. This paper reviews the current state of the art of methods used to model climate change-induced coastal erosion focusing on how climate change-related drivers and the associated uncertainty are considered. We identify research gaps, describe and analyse the key components of a comprehensive framework to derive future estimates of shoreline change and make suggestions for good practice. Within the scope of the review, we find that although significant progress has been made over the last decade, most of the studies limit uncertainty sampling to considering ranges of variation of forcing variables and ensembles of emissions scenarios, and applications with high level of probabilistic development remain few. Further research is necessary to fully (a) incorporate projected time series of coastal drivers into the erosion models, including bias correction; (b) sufficiently sample the uncertainty associated with each step of the top-down approach, including the consideration of different emission scenarios, inter- and intra-model variability, and multiple runs of erosion models or model ensembles; and (c) reduce uncertainty in shoreline change estimates by developing better datasets and model parameterisations, and progressing in detection and attribution
Beliefs on the local effects of climate change: causal attribution of flooding and shoreline retreat
Adaptation to climate change is a process that should engage different participants, including not only researchers and technicians but also other stakeholders and local individuals, and, therefore, it is important to understand their beliefs on the local effects of climate change. Recent studies illustrate a linear relation between coastal distance and scepticism, which is lower in coastal zones than in inland. A possible explanation is that people living inland do not experience (or do not perceive) particular natural hazards as being caused by climate change, or attribute the natural hazards to other causes, apart from climate change. This might influence the relative importance of dealing with direct anthropogenic effects and planning adaptation to climate change. Therefore, the goal of this work was to explore this effect by comparing beliefs on the local effects of climate change in Aveiro region (Portugal), specifically in Baixo Vouga Lagunar (BVL, located in the inner side of Ria de Aveiro Coastal Lagoon, 10 km distance from the coast) with the nearby coastal zone between Esmoriz and Vagueira settlements. Stakeholders were interviewed and local individuals were surveyed in order to explore causal attributions towards relevant local environmental problems and compare with data available from the coastal zone. Natural hazards concerned flooding in BVL and shoreline retreat in the coastal zone. Results suggest that in BVL both stakeholders and local residents did not attribute local natural hazards mostly to climate change. However, in the coastal zone, local natural hazards were indeed mostly attributed to climate change. This attribution to climate change was further correlated to a higher risk perception of natural hazards in the coastal zone but not in BVL. Thereby, it is important to consider distance from the shoreline in order to promote local processes of adaptation to climate change.info:eu-repo/semantics/publishedVersio
Probabilistic sea level projections at the coast by 2100
As sea level is rising along many low-lying and densely populated coastal areas, affected communities are investing resources to assess and manage future socio-economic and ecological risks created by current and future sea level rise. Despite significant progress in the scientific understanding of the physical mechanisms contributing to sea level change, projections beyond 2050 remain highly uncertain. Here, we present recent developments in the probabilistic projections of coastal mean sea level rise by 2100, which provides a summary assessment of the relevant uncertainties. Probabilistic projections can be used directly in some of the decision frameworks adopted by coastal engineers for infrastructure design and land use planning. However, relying on a single probability distribution or a set of distributions based upon a common set of assumptions can understate true uncertainty and potentially misinform users. Here, we put the probabilistic projections published over the last 5 years into context
Uncertainty and Bias in Global to Regional Scale Assessments of Current and Future Coastal Flood Risk
This study provides a literature-based comparative assessment of uncertainties and biases in global to world-regional scale assessments of current and future coastal flood risks, considering mean and extreme sea-level hazards, the propagation of these into the floodplain, people and coastal assets exposed, and their vulnerability. Globally, by far the largest bias is introduced by not considering human adaptation, which can lead to an overestimation of coastal flood risk in 2100 by up to factor 1300. But even when considering adaptation, uncertainties in how coastal societies will adapt to sea-level rise dominate with a factor of up to 27 all other uncertainties. Other large uncertainties that have been quantified globally are associated with socio-economic development (factors 2.3–5.8), digital elevation data (factors 1.2–3.8), ice sheet models (factor 1.6–3.8) and greenhouse gas emissions (factors 1.6–2.1). Local uncertainties that stand out but have not been quantified globally, relate to depth-damage functions, defense failure mechanisms, surge and wave heights in areas affected by tropical cyclones (in particular for large return periods), as well as nearshore interactions between mean sea-levels, storm surges, tides and waves. Advancing the state-of-the-art requires analyzing and reporting more comprehensively on underlying uncertainties, including those in data, methods and adaptation scenarios. Epistemic uncertainties in digital elevation, coastal protection levels and depth-damage functions would be best reduced through open community-based efforts, in which many scholars work together in collecting and validating these data
Global no net loss of natural ecosystems
A global goal of no net loss of natural ecosystems or better has recently been proposed, but such a goal would require equitable translation to country-level contributions. Given the wide variation in ecosystem depletion, these could vary from net gain (for countries where restoration is needed), to managed net loss (in rare circumstances where natural ecosystems remain extensive and human development imperative is greatest). National contributions and international support for implementation also must consider non-area targets factors such as the capacity to conserve and the imperative for human development
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