Search results for "117"
showing 10 items of 539 documents
Carbon isotope stratigraphy, magnetostratigraphy, and 40Ar/39Ar age of the Cretaceous South Atlantic coast, Namibe Basin, Angola
2014
This publication results from Projecto PaleoAngola, an international cooperative research effort among the contributing authors and their institutions, funded by the National Geographic Society, the Petroleum Research Fund of the American Chemical Society, Sonangol E.P., Esso Angola, Fundacao Vida of Angola, LS Films, Maersk, Damco, Safmarine, ISEM at SMU, The Royal Dutch Embassy in Luanda, TAP Airlines, Royal Dutch Airlines, The Saurus Institute, and the Perot Museum of Nature and Science. JS was additionally funded by Yale University and the Alfred Kordelin Foundation. We dedicate this contribution to the late Kalunga Lima, our friend and colleague in Projecto PaleoAngola. We thank Margar…
Compensation of Oxygen Transmittance Effects for Proximal Sensing Retrieval of Canopy–Leaving Sun–Induced Chlorophyll Fluorescence
2018
Estimates of Sun–Induced vegetation chlorophyll Fluorescence (SIF) using remote sensing techniques are commonly determined by exploiting solar and/or telluric absorption features. When SIF is retrieved in the strong oxygen (O 2 ) absorption features, atmospheric effects must always be compensated. Whereas correction of atmospheric effects is a standard airborne or satellite data processing step, there is no consensus regarding whether it is required for SIF proximal–sensing measurements nor what is the best strategy to be followed. Thus, by using simulated data, this work provides a comprehensive analysis about how atmospheric effects impact SIF estimations on proximal sensing, regarding: (…
Comparison of quantitative Holocene temperature reconstructions using multiple proxies from a northern boreal lake
2017
Four biotic proxies (plant macrofossils, pollen, chironomids and diatoms) are employed to quantitatively reconstruct variations in mean July air temperatures ( Tjul) at Lake Loitsana (northern Finland) during the Holocene. The aim is to evaluate the robustness and biases in these temperature reconstructions and to compare the timing of highest Tjul in the individual reconstructions. The reconstructed Tjul values are evaluated in relation to local-scale/site-specific processes associated with the Holocene lake development at Loitsana as these factors have been shown to significantly influence the fossil assemblages found in the Lake Loitsana sediments. While pollen-based temperatures follow…
Photochemical mineralization of terrigenous DOC to dissolved inorganic carbon in ocean
2018
When terrigenous dissolved organic carbon (tDOC) rich in chromophoric dissolved organic matter (tCDOM) enters the ocean, solar radiation mineralizes it partially into dissolved inorganic carbon (DIC). This study addresses the amount and the rates of DIC photoproduction from tDOC and the area of ocean required to photomineralize tDOC. We collected water samples from 10 major rivers, mixed them with artificial seawater, and irradiated them with simulated solar radiation to measure DIC photoproduction and the photobleaching of tCDOM. The linear relationship between DIC photoproduction and tCDOM photobleaching was used to estimate the amount of photoproduced DIC from the tCDOM fluxes of the stu…
Predicting habitat suitability for Ixodes ricinus and Ixodes persulcatus ticks in Finland
2022
AbstractBackgroundTicks are responsible for transmitting several notable pathogens worldwide. Finland lies in a zone where two human-biting tick species co-occur:IxodesricinusandIxodespersulcatus. Tick densities have increased in boreal regions worldwide during past decades, and tick-borne pathogens have been identified as one of the major threats to public health in the face of climate change.MethodsWe used species distribution modelling techniques to predict the distributions ofI.ricinusandI.persulcatus,using aggregated historical data from 2014 to 2020 and new tick occurrence data from 2021. By aiming to fill the gaps in tick occurrence data, we created a new sampling strategy across Fin…
Extracting locations from sport and exercise-related social media messages using a neural network-based bilingual toponym recognition model
2022
Funding: This study is a part of the “Equality in suburban physical activity environments, YLLI” research project (in Finnish: Yhdenvertainen liikunnallinen lähiö, YLLI). The project is being financed by the research program about suburban in Finland “Lähiöohjelma 2020-2022” coordinated by the Ministry of Environment (grant recipient: Dr. Petteri Muukkonen). Sport and exercise contribute to health and well-being in cities. While previous research has mainly focused on activities at specific locations such as sport facilities, “informal sport” that occur at arbitrary locations across the city have been largely neglected. Such activities are more challenging to observe, but this challenge may…
Ethics in biodiversity conservation : The meaning and importance of pluralism
2022
Addressing the global extent of the current biodiversity crisis requires engaging with the existence of multiple equally legitimate values, but also with diverse ethical perspectives underpinning conceptions of right and wrong actions. However, western monist positions have mostly explicitly or implicitly directed conservation strategies by defining the space of legitimate arguments, overlooking solutions that do not fit neatly the chosen approaches. As ignoring diverse ethical positions leads to injustices and reduces the potential of conserving biodiversity, there is a need to recognise and navigate the ethical landscape. Ethical pluralism may provide opportunities to do so. However, the …
Modeling mass transfer in fracture flows with the time domain-random walk method
2019
The time domain-random walk method was developed further for simulating mass transfer in fracture flows together with matrix diffusion in surrounding porous media. Specifically, a time domain-random walk scheme was developed for numerically approximating solutions of the advection-diffusion equation when the diffusion coefficient exhibits significant spatial variation or even discontinuities. The proposed scheme relies on second-order accurate, central-difference approximations of the advective and diffusive fluxes. The scheme was verified by comparing simulated results against analytical solutions in flow configurations involving a rectangular channel connected on one side with a porous ma…
Soiden ennallistamisen suoluonto-, vesistö-, ja ilmastovaikutukset. Vertaisarvioitu raportti.
2021
Tämän selvityksen tarkoituksena on tuottaa kirjallisuuskatsaus ja siihen pohjautuvia johtopäätöksiä soiden ennallistamisen ilmasto-, vesistö- ja suoluontovaikutuksista. Selvitys pyrkii erityisesti kasaamaan yhteen uusimpia tutkimustuloksia ja aineistoja ennallistamisen vaikutuksiin liittyen ja toisaalta muodostamaan kokonaiskuvan laaja-alaisempaa soiden ennallistamisstrategiaa silmällä pitäen. Suoekosysteemit reagoivat kokonai-suutena varsin hyvin perinteisiin ennallistamistoimiin. Ennallistaminen ei kuitenkaan ole ongelmatonta, sillä ennallistamistoimet eli yleensä kaivin- ja metsäkonetyöt sekä ennallistamisen jälkeisen alkuvaiheen voimakkaat ekosysteemin muutokset voivat aiheuttaa yhteisk…
Soiden ennallistamisen suoluonto-, vesistö- ja ilmastovaikutukset : Luontopaneelin yhteenveto ja suositukset luontopolitiikan suunnittelun ja päätöks…
2021
Suomen alkuperäisestä 10,4 miljoonan hehtaarin suoalasta yli puolet on ojitettu metsä- ja maatalouden sekä turvetuotannon tarpeisiin. Etelä-Suomessa ojitus on ollut voimakkainta: keskimäärin noin 75 prosenttia ja monin paikoin vielä suurempi osa soista on ojitettu. Suot ovat Euroopan luontotyypeistä kaikkein uhanalaisin luontotyyppiryhmä ja Suomella on erityisvastuu soiden suojelusta. Kaikkiaan 54 prosenttia Suomen 50 suoluontotyypistä on uhanalaisia ja lisäksi 20 prosenttia on silmällä-pidettäviä. Ensisijaisesti Suomen soilla elävistä lajeista 11 prosenttia eli yhteensä 120 lajia on uhanalaisia. Uhanalaisilla lajeilla ja luontotyypeillä on korkea riski hävitä Suomesta. Mittava ojitus näkyy…