Search results for " fisheries."
showing 10 items of 1015 documents
Financial contagion through space-time point processes
2020
AbstractWe propose to study the dynamics of financial contagion by means of a class of point process models employed in the modeling of seismic contagion. The proposal extends network models, recently introduced to model financial contagion, in a space-time point process perspective. The extension helps to improve the assessment of credit risk of an institution, taking into account contagion spillover effects.
Evaluating a hierarchical approach to landscape-level harvest scheduling
2018
Forest planning at the landscape level has the potential to become a large intractable problem. In Finland, Metsähallitus (the state enterprise that manages federally owned land) creates strategic plans to determine the appropriate harvest level. While these plans are feasible, they are not implementable in practice as the harvests are scattered temporally and spatially. Requiring that harvests be organized both temporally and spatially for practical implementation can result in an intractable problem. Through a hierarchical approach, the problem can be organized into steps in which the intractable problem is broken down into smaller easily solvable parts. As an approximation technique, th…
A competing risks tale on successful and unsuccessful fiscal consolidations
2019
Abstract This paper analyses the transitions out of fiscal consolidations using annual data for 17 industrial countries over the period 1975-2013 and applying a discrete-time competing risks duration model. Our approach allows us to distinguish the factors behind a successful or an unsuccessful end of fiscal consolidation episodes. The results show that economic and political factors, the size and typology of fiscal adjustments and the occurrence of crises explain the differences in the length and the success/failure of fiscal consolidations. Moreover, while fiscal adjustment programmes that end successfully display positive duration dependence, those that end in an unsuccessful manner are …
Use of Wood Ash in the Forest and its Effect on the Concentration of Essential and Heavy Metallic Elements in Soil and Blueberries <i>(Vacciniu…
2020
The aim of this research is to evaluate the influence of wood ash as an additive fertilizer to forest soil and growing blueberries (Vaccinium myrtillus L.) in terms of metallic element content. To evaluate the effect of wood ash on the forest ecosystem, was selected two forest areas which was fertilized with a certain amount of wood ash (bottom ash and fly ash). The selected forest areas were divided into two types of sampling plots (fertilized with ash and control). Obtained results showed that in the bottom ash dispersion area the concentration of Ca, K, Ni, Cu is almost twice higher in the fertilized plots than control plots. In the blueberries, metallic element content is similar and do…
A reactive nitrogen budget for forest land and wetlands in Latvia and Estonia
2020
Human intervention in global nitrogen cycling has led to excess reactive nitrogen (Nr) flows to the environment, impacting terrestrial ecosystems as well as the quality of the atmosphere and waterb...
Adsorption et desorption de la terbutryne par une montmorillonite-Ca et des acides humiques seuls ou en melanges
1977
Resume: L' effet du pH sur l'adsorption de la terbutryne par des acides humiques, une montmorillonite-Ca ou leurs melanges montre une certaine similitude de comportement entre ces derniers et l'argile seule. Au voisinage de la neutralite, seuls les acides humiques adsorbent la terbutryne. En milieu acide, les isothermes d'adsorption de la terbutryne par les acides humiques et la montmorillonite sont respectivement de type L et S et traduisent une affinite adsorbat-adsorbant differente; les isothermes d'adsorption correspondant aux melanges ont une forme differente et font apparaitre un effet de synergie, en particulier dans le cas des melanges pauvres en acides humiques. La dsorption saccom…
Fishing pressure impacts the abundance gradient of European lobsters across the borders of a newly established marine protected area
2019
Marine protected areas (MPAs) are considered viable fisheries management tools due to their potential benefits of adult spillover and recruitment subsidy to nearby fisheries. However, before–after control–impact studies that explore the biological and fishery effects of MPAs to surrounding fisheries are scarce. We present results from a fine-scale spatial gradient study conducted before and after the implementation of a 5 km 2 lobster MPA in southern Norway. A significant nonlinear response in lobster abundance, estimated as catch-per-unit-effort (CPUE) from experimental fishing, was detected within 2 years of protection. After 4 years, CPUE values inside the MPA had increased by a magnitu…
Proactive avoidance behaviour and pace-of-life syndrome in Atlantic salmon
2019
Individuals in a fish population differ in key life-history traits such as growth rate and body size. This raises the question of whether such traits cluster along a fast-slow growth continuum according to a pace-of-life syndrome (POLS). Fish species like salmonids may develop a bimodal size distribution, providing an opportunity to study the relationships between individual growth and behavioural responsiveness. Here we test whether proactive characteristics (bold behaviour coupled with low post-stress cortisol production) are related to fast growth and developmental rate in Atlantic salmon, Salmo salar . Boldness was tested in a highly controlled two-tank hypoxia test were oxygen levels …
Snowpack concentrations and estimated fluxes of volatile organic compounds in a boreal forest
2012
Abstract. Soil provides an important source of volatile organic compounds (VOCs) to atmosphere, but in boreal forests these fluxes and their seasonal variations have not been characterized in detail. Especially wintertime fluxes are almost completely unstudied. In this study, we measured the VOC concentrations inside the snowpack in a boreal Scots pine (Pinus sylvestris L.) forest in southern Finland, using adsorbent tubes and air samplers installed permanently in the snow profile. Based on the VOC concentrations at three heights inside the snowpack, we estimated the fluxes of these gases. We measured 20 VOCs from the snowpack, monoterpenes being the most abundant group with concentrations …
Sentinel-1 & Sentinel-2 Data for Soil Tillage Change Detection
2018
In this paper, an algorithm using Sentinel-1 (S-1) and Sentinel-2 (S-2) data to identify changes of tillage over agricultural fields at approximately similar to 100m resolution is presented. The methodology implements a multiscale temporal change detection on S-1 VH backscatter in order to single out VH changes due to agricultural practices only. The algorithm can be applied over bare or scarcely vegetated agricultural fields, which are identified from S-2 NDVI measurements. An initial assessment at farm scale using in situ and S-1 and SPOT5-Take5 data, acquired over the Apulian Tavoliere in southern Italy in 2015, is illustrated. A full validation of the approach is in progress over three …