38 research outputs found

    Assessing forest availability for wood supply in Europe

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    The quantification of forests available for wood supply (FAWS) is essential for decision-making with regard to the maintenance and enhancement of forest resources and their contribution to the global carbon cycle. The provision of harmonized forest statistics is necessary for the development of forest associated policies and to support decision-making. Based on the National Forest Inventory (NFI) data from 13 European countries, we quantify and compare the areas and aboveground dry biomass (AGB) of FAWS and forest not available for wood supply (FNAWS) according to national and reference definitions by determining the restrictions and associated thresholds considered at country level to classify forests as FAWS or FNAWS. FAWS represent between 75 and 95 % of forest area and AGB for most of the countries in this study. Economic restrictions are the main factor limiting the availability of forests for wood supply, accounting for 67 % of the total FNAWS area and 56 % of the total FNAWS AGB, followed by environmental restrictions. Profitability, slope and accessibility as economic restrictions, and protected areas as environmental restrictions are the factors most frequently considered to distinguish between FAWS and FNAWS. With respect to the area of FNAWS associated with each type of restriction, an overlap among the restrictions of 13.7 % was identified. For most countries, the differences in the FNAWS areas and AGB estimates between national and reference definitions ranged from 0 to 5 %. These results highlight the applicability and reliability of a FAWS reference definition for most of the European countries studied, thereby facilitating a consistent approach to assess forests available for supply for the purpose of international reportinginfo:eu-repo/semantics/publishedVersio

    Boson gas in a periodic array of tubes

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    We report the thermodynamic properties of an ideal boson gas confined in an infinite periodic array of channels modeled by two, mutually perpendicular, Kronig-Penney delta-potentials. The particle's motion is hindered in the x-y directions, allowing tunneling of particles through the walls, while no confinement along the z direction is considered. It is shown that there exists a finite Bose- Einstein condensation (BEC) critical temperature Tc that decreases monotonically from the 3D ideal boson gas (IBG) value T0T_{0} as the strength of confinement P0P_{0} is increased while keeping the channel's cross section, axaya_{x}a_{y} constant. In contrast, Tc is a non-monotonic function of the cross-section area for fixed P0P_{0}. In addition to the BEC cusp, the specific heat exhibits a set of maxima and minima. The minimum located at the highest temperature is a clear signal of the confinement effect which occurs when the boson wavelength is twice the cross-section side size. This confinement is amplified when the wall strength is increased until a dimensional crossover from 3D to 1D is produced. Some of these features in the specific heat obtained from this simple model can be related, qualitatively, to at least two different experimental situations: 4^4He adsorbed within the interstitial channels of a bundle of carbon nanotubes and superconductor-multistrand-wires Nb3_{3}Sn.Comment: 9 pages, 10 figures, submitte

    Linear-T scattering and pairing from antiferromagnetic fluctuations in the (TMTSF)_2X organic superconductors

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    An exhaustive investigation of metallic electronic transport and superconductivity of organic superconductors (TMTSF)_2PF_6 and (TMTSF)_2ClO_4 in the Pressure-Temperature phase diagram between T=0 and 20 K and a theoretical description based on the weak coupling renormalization group method are reported. The analysis of the data reveals a high temperature domain (T\approx 20 K) in which a regular T^2 electron-electron Umklapp scattering obeys a Kadowaki-Woods law and a low temperature regime (T< 8 K) where the resistivity is dominated by a linear-in temperature component. In both compounds a correlated behavior exists between the linear transport and the extra nuclear spin-lattice relaxation due to antiferromagnetic fluctuations. In addition, a tight connection is clearly established between linear transport and T_c. We propose a theoretical description of the anomalous resistivity based on a weak coupling renormalization group determination of electron-electron scattering rate. A linear resistivity is found and its origin lies in antiferromagnetic correlations sustained by Cooper pairing via constructive interference. The decay of the linear resistivity term under pressure is correlated with the strength of antiferromagnetic spin correlations and T_c, along with an unusual build-up of the Fermi liquid scattering. The results capture the key features of the low temperature electrical transport in the Bechgaard salts

    Assessing forest availability for wood supply in Europe

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    14 Pág.The quantification of forests available for wood supply (FAWS) is essential for decision-making with regard to the maintenance and enhancement of forest resources and their contribution to the global carbon cycle. The provision of harmonized forest statistics is necessary for the development of forest associated policies and to support decision-making. Based on the National Forest Inventory (NFI) data from 13 European countries, we quantify and compare the areas and aboveground dry biomass (AGB) of FAWS and forest not available for wood supply (FNAWS) according to national and reference definitions by determining the restrictions and associated thresholds considered at country level to classify forests as FAWS or FNAWS. FAWS represent between 75 and 95 % of forest area and AGB for most of the countries in this study. Economic restrictions are the main factor limiting the availability of forests for wood supply, accounting for 67 % of the total FNAWS area and 56 % of the total FNAWS AGB, followed by environmental restrictions. Profitability, slope and accessibility as economic restrictions, and protected areas as environmental restrictions are the factors most frequently considered to distinguish between FAWS and FNAWS. With respect to the area of FNAWS associated with each type of restriction, an overlap among the restrictions of 13.7 % was identified. For most countries, the differences in the FNAWS areas and AGB estimates between national and reference definitions ranged from 0 to 5 %. These results highlight the applicability and reliability of a FAWS reference definition for most of the European countries studied, thereby facilitating a consistent approach to assess forests available for supply for the purpose of international reporting.This research was supported by the Specific contract n. 18 “Use of National Forest Inventories data to estimate area and above ground biomass in European forests not available for wood supply” in the context of the Framework contract for the provision of forest data and services supporting the European Forest Data Centre 2012/ S 78-127532 of 21/04/2012 of the Joint Research Centre of the European Commission; the EG-013-72 agreement of the Ministry of Agriculture, Fisheries and Food (MAPA) and the INIA belonging to the Spanish Ministry of Science and Innovation (MICINN); and the project No.APVV-15-0265 granted by the Slovak Research and Development Agency.Peer reviewe

    Improved large-area forest increment information in Europe through harmonisation of National Forest Inventories

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    14 Pág.Consistent knowledge about the increment in European forests gained amplified importance in European policies and decision processes related to forest-based bioeconomy, carbon sequestration, sustainable forest management and environmental changes. Until now, large-area increment information from European countries was lacking international comparability. In this study we present a harmonisation framework in accordance with the principles and the approach established for the harmonisation of National Forest Inventories (NFIs) in Europe. 11 European NFIs, representing a broad range of increment measurement and estimation methods, developed unified reference definitions and methods that were subsequently implemented to provide harmonised increment estimates by NUTS regions (Nomenclature of territorial units for statistics of the European Union), main forest types and tree species groups, and to rate the impact of harmonisation measures. The main emphasis was on gross annual increment (GAI), however, also annual natural losses (ANL) and net annual increment (NAI) were estimated. The data from the latest available NFI cycles were processed. The participating countries represent a forest area of about 130 million ha, and 82% of the European Unions’ (EU) forest area, respectively. The increments were estimated in terms of volume (m³ year−1, m³ ha−1 year−1) and above-ground biomass (t year−1, t ha−1 year−1). The harmonised GAI volume estimates deviate in a range of +12.3% to −26.5% from the estimates according to the national definitions and estimation methods. Within the study area, the harmonised estimates show a considerable range over the NUTS regions for GAI, from 0.6 to 12.3 m³ ha−1 year−1, and 0.8–6.4 t ha−1 year−1, of volume and above-ground biomass, respectively. The largest increment estimates are found in Central Europe and gradually decrease towards the North, South, West and East. In most countries coniferous forests show larger increment estimates per hectare than broadleaved forests while mixed forests are at an intermediate level. However, in some instances, the differences were small or mixed forests revealed the largest increment estimates. The most important tree species groups in the study area are Pinus spp. and Picea spp., contributing 29% and 26% of the estimated total GAI volume, respectively. The shares of the prevalent broadleaved species are smaller with contributions of 9%, 7% and 6% by Quercus spp., Fagus sylvatica and Betula spp. The results underline the importance of harmonisation in international forest statistics. Looking ahead, harmonised large-area increment estimation is pivotal for accurate monitoring and evidence-based policy decisions in the changing context of future forest ecosystems dynamics, management strategies and wood availability.This research was supported by the Specific Contracts No. 20 and 21 “Use of National Forest Inventories data to harmonise and improve the current knowledge on forest increment in Europe” in the context of the “Framework contract for the provision of forest data and services in support to the JRC activities and applications on forest resources (Contract Number 934340)” of the Joint Research Centre of the European Commission.Peer reviewe

    Multiparameter assessment of mouse oogenesis during follicular growth in vitro

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    Data Management for Monitoring Forest Soils in Europe for the Biosoil Project

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    Growing environmental awareness and advances in modelling have generated interest in soil monitoring networks. Data management tools have to be developed in order to store data, check for errors and retrieve data for sharing and for analysis. As a result, we have designed a web application and a database for the Biosoil project that focuses on European forest soils. Integral to the system are authentication of users and access rights to the modules and data. It also logs all activities of each user. During data submission, the system automatically manages data transfer from the flat file (ASCII file) to the database after compliance checks. Then error tracking is followed by automated expert checks. These checks identify potential mistakes that can be corrected or commented on by data providers. The database is intended to cope with the challenges of transnational monitoring and integrates data quality assurance / quality control mechanisms. Benefits from the architecture of the database and from the services provided by the software may be generalized to all soil monitoring databases in order to improve data management and quality control.JRC.H.7-Climate Risk Managemen

    Spontaneous calcium oscillations and nuclear PLC-beta1 in human GV oocytes

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    Our aim was to investigate if human oocytes, like mouse oocytes, exhibit spontaneous Ca(2+) oscillations and nuclear translocation of PLC-beta1 prior to germinal vesicle breakdown (GVBD), and to correlate these events with the evolution of chromatin configuration as a landmark for the meiosis resumption kinetics. Human germinal vesicle (GV) oocytes were either loaded with Fluo-3 probe to record Ca(2+) signals or fixed for subsequent fluorescent labeling of both chromatin and PLC-beta1, and immunogold labeling of PLC-beta1. Here for the first time, we show that human oocytes at the GV-stage exhibit spontaneous Ca(2+) oscillations. Interestingly, only oocytes with a large diameter and characterized by a compact chromatin surrounding the nucleolus of the GV could reveal these kind of oscillations. We also observed a translocation of PLC-beta1 from the cytoplasm towards the nucleus during in vitro maturation of human oocytes. Spontaneous calcium oscillations and nuclear translocation of PLC-beta1 may reflect some degree of oocyte maturity. The impact of our results may be very helpful to understand and resolve many enigmatic problems usually encountered during the in vitro meiotic maturation of human GV oocytes
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