Tartu, Estonia

Founded in 1938, the Estonian Academy of science is Estonia's national academy of science in Tallinn. As with other national academies, it is an independent group of well-known scientists whose stated aim is to promote research and development, encourage international scientific cooperation, and disseminate knowledge to the public. As of December 2012, it had 75 full members and 15 foreign members. Since November 2004, the president of the Academy is Richard Villems, a biologist from the University of Tartu. Wikipedia.


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Viikmae B.,Tallinn University of Technology | Soomere T.,Tallinn University of Technology | Soomere T.,Estonian Academy of Sciences
Journal of Marine Systems | Year: 2014

The spatial pattern of hits to the nearshore by tracers originating in a major fairway in the Gulf of Finland and transported by surface currents is analysed based on Lagrangian trajectories of water parcels reconstructed using the TRACMASS model from three-dimensional velocity fields by the Rossby Centre circulation model RCO for 1987-1996. The probabilities for a hit to different parts of the nearshore and the ability of different sections of the fairway to serve as starting points of tracers (equivalently, certain type of nearshore pollution) have extensive seasonal variability. The potential of the fairway to impact the nearshore in this manner is roughly inversely proportional to its distance from the nearest coast. A short section of the fairway to the south of Vyborg and a segment to the west of Tallinn are the most probable starting points of tracers. The most frequently hit nearshore areas are short fragments between Hanko and Helsinki, the north-eastern coast of the gulf to the south of Vyborg, and longer segments from Tallinn to Hiiumaa on the southern coast of the gulf. © 2013 Elsevier B.V.


Soomere T.,Tallinn University of Technology | Soomere T.,Estonian Academy of Sciences | Viska M.,Tallinn University of Technology
Journal of Marine Systems | Year: 2014

Alongshore variations in sediment transport along the eastern Baltic Sea coast from the Sambian (Samland) Peninsula up to Pärnu Bay in the Gulf of Riga are analysed using long-term (1970-2007) simulations of the nearshore wave climate and the Coastal Engineering Research Centre (CERC) wave energy flux model applied to about 5.5. km long beach sectors. The local rate of bulk transport is the largest along a short section of the Sambian Peninsula and along the north-western part of the Latvian coast. The net transport has an overall counter-clockwise nature but contains a number of local temporary reversals. The alongshore sediment flux has several divergence and convergence points. One of the divergence points at the Akmenrags Cape divides the sedimentary system of the eastern coast of the Baltic Proper into two almost completely separated compartments in the simulated wave climate. Cyclic relocation of a highly persistent convergence point over the entire Curonian Spit suggests that this landform is in almost perfect dynamical equilibrium in the simulated approximation of the contemporary wave climate. © 2013 Elsevier B.V.


Soomere T.,Tallinn University of Technology | Soomere T.,Estonian Academy of Sciences | Raamet A.,Tallinn University of Technology
Journal of Marine Systems | Year: 2014

The analysis of decadal changes to the average and extreme wave properties in the Baltic Sea is performed based on the wave hindcast for the entire Baltic Sea 1970-2007 using the wave model WAM and adjusted geostrophic winds under the assumption of no ice cover. The overall wave activity in the entire basin has limited variations over the 38. years of simulations. The local wave properties reveal strong decadal-scale signal in many parts of this water body. Its amplitude is up to 15% of the long-term average value of the significant wave height. The typical time interval between episodes of high or low annual average significant wave height is 10-12. years. The analogous interval between episodes of high and low 99%-iles of wave heights is about 5. years. Changes to the wave properties in different sea areas may be completely different in different decades. The overall maximum in the simulated annual mean significant wave height has drifted from an area between Gotland and Öland in the 1970s to the northern Baltic Proper at the turn of the millennium. © 2013 Elsevier B.V.


Soomere T.,Tallinn University of Technology | Soomere T.,Estonian Academy of Sciences | Eelsalu M.,Tallinn University of Technology
Renewable Energy | Year: 2014

We analyse the wave energy resource theoretically and practically available in a semi-sheltered shelf sea of moderate depth and with relatively severe but highly intermittent wave climate on the example of the Baltic Sea. The wave properties along the entire eastern Baltic Sea coast, from the Sambian (Samland) Peninsula to the eastern Gulf of Finland, are reconstructed numerically for 1970-2007 with a spatial resolution of 3 nautical miles (5.5km) and temporal resolution of 1h using the third generation wave model WAM. Owing to the shallowness of the sea (54m on average) the finite-depth dispersion relation is used in the estimates of the wave energy resources in the nearshore, at depths of 7-48m where the WAM model provides adequate results. The average wave energy flux (wave power) over the 38 years in question is about 1.5kW/m (at selected locations up to 2.55kW/m) in the nearshore regions of the eastern Baltic Proper but much smaller, about 0.7kW/m, in the interior of the Gulf of Finland and the Gulf of Riga. The total theoretical wave energy resource in the entire study area is about 1.5GW. The existing and proposed marine protected areas limit the available wave energy resource down to ~840MW. The production of grid energy is complicated because of extremely high intermittency and strong seasonal variation of the wave properties and frequent presence of sea ice. Although the wave energy resources are of obvious interest at some locations, their use for supplying power into the grid is questionable and probably not feasible in the conceivable future. © 2014 Elsevier Ltd.


Delpeche-Ellmann N.C.,Tallinn University of Technology | Soomere T.,Tallinn University of Technology | Soomere T.,Estonian Academy of Sciences
Marine Pollution Bulletin | Year: 2013

The possibility of current-driven propagation of contaminants released along a major fairway polluting the Marine Protected Areas (MPAs) in the Gulf of Finland, the Baltic Sea, is examined using a 3D circulation model, a Lagrangian transport model and statistics. Not surprisingly, the number of hits to the MPA decreases almost linearly with its distance from the fairway. In addition, the potential pollution released during a ship accident with the pollutants carried by currents may affect MPAs at very large distances. Typically, a fairway section approximately 125. km long (covering about 1/3 of the approximate 400-km-long gulf) may serve as a source of pollution for each MPA. The largest MPA (in the Eastern Gulf of Finland) may receive pollution from an approximately 210-km-long section (covering about 1/2 of the entire length of the gulf). This information may be useful in assisting maritime management. © 2012 Elsevier Ltd.


News Article | December 19, 2016
Site: www.eurekalert.org

A new study led by a research scientist at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) highlights a literally shady practice in plant science that has in some cases underestimated plants' rate of growth and photosynthesis, among other traits. The study, published Dec. 19 in Nature Plants, suggests that this problem may stem from a common tendency in fieldwork to report leaf measurements taken in partially shaded conditions as existing in more fully sunlit conditions. As a result, global plant databases and models may require updating to better account for plant responses to full-sun conditions, said Trevor F. Keenan, a research scientist in Berkeley Lab's Earth and Environmental Sciences Area who led the study. "Often when researchers are in the field, it's hard to get to leaves at the top of trees," Keenan said, particularly in densely vegetated areas such as tropical forests where the canopies can reach over 100 feet in height. "In other cases, understory plants grow mostly in the shade, so it is impossible to sample in full sun. Traits vary quite a lot in the canopy, so if you don't sample from the top all of your samples will be biased," he said. In plant fieldwork, full-sun conditions are defined as those in which a plant receives the maximum amount of sunlight, typically at the top of a canopy, but most leaves do not grow in full-sun conditions. Leaves at the bottom of the canopy in a tropical rainforest may receive 100 times less sunlight than those at the top of the canopy, Keenan said. And many leaf characteristics -- which are integral to vital leaf functions such as carbon uptake and photosynthesis -- can vary 20-fold between the top and bottom leaves on the same plant. "For example, the highest concentration in nitrogen is at the top, where you have the most sunlight. Plants allocate a lot of nutrients there so they can 'profit' from it the most," Keenan said. Keenan and U?lo Niinemets, a researcher from the Estonian University of Life Sciences and Estonian Academy of Sciences, evaluated leaf data from several databases -- covering hundreds of plant species and spanning most regions of the world -- in the latest study. They used data from those studies that reported extra information about the specific location of the sampled leaves in the canopy as a benchmark for other studies' data. The research was conducted as Keenan and colleagues were assembling a new global database for plant research. The misreported sun vs. shade conditions are likely most pronounced in tropical regions, Keenan said. Because these regions of tropical vegetation are also considered to be the planet's largest "carbon sinks" in removing carbon dioxide from the atmosphere, "These are some of the most important areas to focus on," he said. Better accounting of light conditions that sampled leaves are growing in could help to improve models that account for plants' total rate of photosynthesis and better quantify their role as a carbon sink, for example, and for plants' adaptability to changing conditions. It can also identify important correlations between which plant traits are most pronounced under different lighting conditions. More accurate sampling methods can ultimately help improve scientists' understanding of whole ecosystem structure and function, and to understand how plants respond to factors such as climate change, the study states. In addition to improved reporting of sunlit conditions, there is also a need for better accounting of plant ages in field studies, as age may affect leaf chemistry and function, according to the study. The study concludes that field studies must take more care in accurately reporting sunlit vs. shaded conditions and age-driven trait responses in leaves. "These results will hopefully help to improve field measurement strategies," Keenan said. More standardized fieldwork, in parallel with new computational tools and theoretical work, will contribute to better global plant models, Keenan said. Researchers will likely tap the supercomputing capabilities of Berkeley Lab's National Energy Research Scientific Computing Center (NERSC) in upcoming modeling work. "We really don't know how plants are going to acclimate to a changing climate," Keenan said, noting that Lab researchers are developing a theory for why plants acclimate and change their allocations of nutrients within the canopy. "We can use this to better understand why trait values vary." New techniques are emerging to improve data collection in the field, Keenan also said. The study notes that some field research has used a shotgun approach to sample leaves at the top of the canopy -- firing a shotgun to clip off leaves that are otherwise out of reach -- though this technique alters the water flow that exists in attached leaves, so it can affect photosynthesis measurements. LIDAR, a laser-based mapping technology, has found more use in plant field work, Keenan noted, by providing 3-D images of forest structure, for example, and physics-based computer simulations are improving in their ability to model how leaves transfer energy from sunlight. "There is definitely a path forward in technological and scientific advances, along with new measurement approaches," he said. "There is a lot of work to be done." NERSC is a DOE Office of Science User Facility. This work was supported by Berkeley Lab's Laboratory Directed Research and Development fund and by DOE's Office of Science. Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit http://www. . DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.


Freiberg A.,University of Tartu | Freiberg A.,Estonian Academy of Sciences | Ratsep M.,University of Tartu | Timpmann K.,University of Tartu
Biochimica et Biophysica Acta - Bioenergetics | Year: 2012

Integral membrane proteins constitute more than third of the total number of proteins present in organisms. Solubilization with mild detergents is a common technique to study the structure, dynamics, and catalytic activity of these proteins in purified form. However beneficial the use of detergents may be for protein extraction, the membrane proteins are often denatured by detergent solubilization as a result of native lipid membrane interactions having been modified. Versatile investigations of the properties of membrane-embedded and detergent-isolated proteins are, therefore, required to evaluate the consequences of the solubilization procedure. Herein, the spectroscopic and kinetic fingerprints have been established that distinguish excitons in individual detergent-solubilized LH2 light-harvesting pigment-protein complexes from them in the membrane-embedded complexes of purple photosynthetic bacteria Rhodobacter sphaeroides. A wide arsenal of spectroscopic techniques in visible optical range that include conventional broadband absorption-fluorescence, fluorescence anisotropy excitation, spectrally selective hole burning and fluorescence line-narrowing, and transient absorption-fluorescence have been applied over broad temperature range between physiological and liquid He temperatures. Significant changes in energetics and dynamics of the antenna excitons upon self-assembly of the proteins into intracytoplasmic membranes are observed, analyzed, and discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. © 2011 Elsevier B.V. All rights reserved.


Niinemets U.,Estonian University of Life Sciences | Niinemets U.,Estonian Academy of Sciences | Sun Z.,Estonian University of Life Sciences
Journal of Experimental Botany | Year: 2015

Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 μmol mol-1 or elevated [CO2] of 780 μmol mol-1. The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size. © The Author 2014.


News Article | December 19, 2016
Site: phys.org

The study, published Dec. 19 in Nature Plants, suggests that this problem may stem from a common tendency in fieldwork to report leaf measurements taken in partially shaded conditions as existing in more fully sunlit conditions. As a result, global plant databases and models may require updating to better account for plant responses to full-sun conditions, said Trevor F. Keenan, a research scientist in Berkeley Lab's Earth and Environmental Sciences Area who led the study. "Often when researchers are in the field, it's hard to get to leaves at the top of trees," Keenan said, particularly in densely vegetated areas such as tropical forests where the canopies can reach over 100 feet in height. "In other cases, understory plants grow mostly in the shade, so it is impossible to sample in full sun. Traits vary quite a lot in the canopy, so if you don't sample from the top all of your samples will be biased," he said. In plant fieldwork, full-sun conditions are defined as those in which a plant receives the maximum amount of sunlight, typically at the top of a canopy, but most leaves do not grow in full-sun conditions. Leaves at the bottom of the canopy in a tropical rainforest may receive 100 times less sunlight than those at the top of the canopy, Keenan said. And many leaf characteristics—which are integral to vital leaf functions such as carbon uptake and photosynthesis—can vary 20-fold between the top and bottom leaves on the same plant. "For example, the highest concentration in nitrogen is at the top, where you have the most sunlight. Plants allocate a lot of nutrients there so they can 'profit' from it the most," Keenan said. Cutting to the root of a data problem Keenan and U?lo Niinemets, a researcher from the Estonian University of Life Sciences and Estonian Academy of Sciences, evaluated leaf data from several databases—covering hundreds of plant species and spanning most regions of the world—in the latest study. They used data from those studies that reported extra information about the specific location of the sampled leaves in the canopy as a benchmark for other studies' data. The research was conducted as Keenan and colleagues were assembling a new global database for plant research. The misreported sun vs. shade conditions are likely most pronounced in tropical regions, Keenan said. Because these regions of tropical vegetation are also considered to be the planet's largest "carbon sinks" in removing carbon dioxide from the atmosphere, "These are some of the most important areas to focus on," he said. Better accounting of light conditions that sampled leaves are growing in could help to improve models that account for plants' total rate of photosynthesis and better quantify their role as a carbon sink, for example, and for plants' adaptability to changing conditions. It can also identify important correlations between which plant traits are most pronounced under different lighting conditions. More accurate sampling methods can ultimately help improve scientists' understanding of whole ecosystem structure and function, and to understand how plants respond to factors such as climate change, the study states. In addition to improved reporting of sunlit conditions, there is also a need for better accounting of plant ages in field studies, as age may affect leaf chemistry and function, according to the study. The study concludes that field studies must take more care in accurately reporting sunlit vs. shaded conditions and age-driven trait responses in leaves. "These results will hopefully help to improve field measurement strategies," Keenan said. More standardized fieldwork, in parallel with new computational tools and theoretical work, will contribute to better global plant models, Keenan said. Researchers will likely tap the supercomputing capabilities of Berkeley Lab's National Energy Research Scientific Computing Center (NERSC) in upcoming modeling work. "We really don't know how plants are going to acclimate to a changing climate," Keenan said, noting that Lab researchers are developing a theory for why plants acclimate and change their allocations of nutrients within the canopy. "We can use this to better understand why trait values vary." New techniques are emerging to improve data collection in the field, Keenan also said. The study notes that some field research has used a shotgun approach to sample leaves at the top of the canopy—firing a shotgun to clip off leaves that are otherwise out of reach—though this technique alters the water flow that exists in attached leaves, so it can affect photosynthesis measurements. LIDAR, a laser-based mapping technology, has found more use in plant field work, Keenan noted, by providing 3-D images of forest structure, for example, and physics-based computer simulations are improving in their ability to model how leaves transfer energy from sunlight. "There is definitely a path forward in technological and scientific advances, along with new measurement approaches," he said. "There is a lot of work to be done." Explore further: Soybean plants with fewer leaves yield more


Tyugu E.,Estonian Academy of Sciences
2011 3rd International Conference on Cyber Conflict, ICCC 2011 - Proceedings | Year: 2011

The speed of processes and the amount of data to be used in defending the cyber space cannot be handled by humans without considerable automation. However, it is difficult to develop software with conventional fixed algorithms (hard-wired logic on decision making level) for effectively defending against the dynamically evolving attacks in networks. This situation can be handled by applying methods of artificial intelligence that provide flexibility and learning capability to software. This paper presents a brief survey of artificial intelligence applications in cyber defense (CD), and analyzes the prospects of enhancing the cyber defense capabilities by means of increasing the intelligence of the defense systems. After surveying the papers available about artificial intelligence applications in CD, we can conclude that useful applications already exist. They belong, first of all, to applications of artificial neural nets in perimeter defense and some other CD areas. From the other side - it has become obvious that many CD problems can be solved successfully only when methods of artificial intelligence are being used. For example, wide knowledge usage is necessary in decision making, and intelligent decision support is one of yet unsolved problems in CD. © 2011 Cooperative Cyber Defenc.

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