Tallinn University of Technology

About: Tallinn University of Technology is a education organization based out in Tallinn, Estonia. It is known for research contribution in the topics: European union & Oil shale. The organization has 3688 authors who have published 10313 publications receiving 145058 citations. The organization is also known as: Tallinn Technical University & Tallinna Tehnikaülikool.

Detection, distribution and control of Potato mop‐top virus, a soil‐borne virus, in northern Europe

Abstract: Potato mop-top virus (PMTV; genus Pomovirus; family Virgaviridae) is transmitted bythesoil-borneSpongosporasubterraneaf.sp.subterranea,aprotoctistthatcauses powdery scab on potato. PMTV is distributed widely in the potato growing areas in South and North America, Japan and northwestern Europe. This article reviews the current knowledge on detection, distribution and control of PMTV with focus on the Baltic Sea region. Since the 1980s, PMTV has caused great economic losses to potato production in the Nordic countries (Norway, Sweden, Denmark and Finland), but its occurrence in other countries of the Baltic Sea region remained unknown. To fill this knowledge gap, harmonised sampling and virus detection procedures including bioassays and serological and molecular methods were employed by 21 research institutions to detect PMTV in potato tubers and soil samples in 2005‐2008. Potato growing areas were widely contaminated with PMTV in the Nordic countries. Only the main seed potato production area in northern Sweden and the High Grade seed potato production zone in Finland were negative for PMTV. Intensive and

Modeling of the mesoscale structure of coupled upwelling/downwelling events and the related input of nutrients to the upper mixed layer in the Gulf of Finland, Baltic Sea

Abstract: [1] A high resolution numerical study is undertaken to simulate an upwelling event along the northern coast of the Gulf of Finland, 21–29 July 1999, which was documented well by in situ and remote measurements. The simulated sequence of SST maps shows a reasonably good resemblance to that of satellite infrared imagery, including both mesoscale coherent structures (filaments or squirts) and the whole process of post-upwelling relaxation of the temperature field. Upwelling along the northern coast of the Gulf is accompanied by downwelling along the southern coast so that two longshore baroclinic jets and related fronts are developed simultaneously. When the strong westerly winds producing the upwelling/downwelling weaken, the longshore jets become unstable and produce transverse jets, cold/warm water squirts. Using pseudo-random simulated fields of temperature and velocity of currents, the apparent lateral diffusivity due to squirts is directly estimated at 500 m2 s−1. The model is also applied to estimate nutrient transport. Simulated phosphate concentration in the surface layer at the cold side of upwelling front is found to be about 0.3 mmol m−3 which is consistent with observations. The total content of phosphorus and nitrogen in the upper 10 m layer of the Gulf introduced by the upwelling event is estimated to be 387 and 36 tons, respectively. It follows, that the upwelling event transports nutrients into the upper layer with clear excess of phosphorus (N:P = 36:387 = 0.093) compared to the Redfield ratio of 7.2. Therefore phosphorus input caused by upwelling during summer most likely promotes nitrogen-fixing cyanobacteria blooms.

A 160,000-year-old history of tectonically controlled methane seepage in the Arctic.

Abstract: The geological factors controlling gas release from Arctic deep-water gas reservoirs through seabed methane seeps are poorly constrained. This is partly due to limited data on the precise chronology of past methane emission episodes. Here, we use uranium-thorium dating of seep carbonates sampled from the seabed and from cores drilled at the Vestnesa Ridge, off West Svalbard (79°N, ~1200 m water depth). The carbonate ages reveal three emission episodes during the Penultimate Glacial Maximum (~160,000 to 133,000 years ago), during an interstadial in the last glacial (~50,000 to 40,000 years ago), and in the aftermath of the Last Glacial Maximum (~20,000 to 5,000 years ago), respectively. This chronology suggests that glacial tectonics induced by ice sheet fluctuations on Svalbard mainly controlled methane release from Vestnesa Ridge. Data corroborate past methane release in response to Northern Hemisphere cryosphere variations and suggest that Arctic deep-water gas reservoirs are sensitive to temperature variations over Quaternary time scales.

Income Underreporting by Households with Business Income. Evidence from Estonia

Abstract: This article estimates the extent of income underreporting by households with business income relative to households of wage earners in Estonia. It uses a modified version of the methodology pioneered by Pissarides and Weber. The extent of income underreporting is estimated by comparing food Engel curves for households with and without reported business income. The baseline result is that the reported total income of households with business income above 20% of total income must be multiplied by 2.6 in order to attain the same propensity to food consumption as households of wage earners. In this sense, households with business income underreport 62% of their ‘true’ total income. Households with reported business income above 0 but below 20% also underreport income but to a lesser extent. The estimates are higher than those found for developed countries but consistent with other studies of unreported activities in transition countries.