A look at aerosol formation using data mining techniques

International audienceAtmospheric aerosol particle formation is frequently observed throughout the atmosphere, but despite various attempts of explanation, the processes behind it remain unclear. In this study data mining techniques were used to find the key parameters needed for atmospheric aerosol particle formation to occur. A dataset of 8 years of 80 variables collected at the boreal forest station (SMEAR II) in Southern Finland was used, incorporating variables such as radiation, humidity, SO2, ozone and present aerosol surface area. Data analysis were done using clustering and classification methods. The aim of this approach was to gain new parameters independent of any subjective interpretation. This resulted in two key parameters, relative humidity and preexisting aerosol particle surface (condensation sink), capable in explaining 88% of the nucleation events. The inclusion of any further parameters did not improve the results notably. Using these two variables it was possible to derive a nucleation probability function. Interestingly, the two most important variables are related to mechanisms that prevent the nucleation from starting and particles from growing, while parameters related to initiation of particle formation seemed to be less important. Nucleation occurs only with low relative humidity and condensation sink values. One possible explanation for the effect of high water content is that it prevents biogenic hydrocarbon ozonolysis reactions from producing sufficient amounts of low volatility compounds, which might be able to nucleate. Unfortunately the most important biogenic hydrocarbon compound emissions were not available for this study. Another effect of water vapour may be due to its linkage to cloudiness which may prevent the formation of nucleating and/or condensing vapours. A high number of preexisting particles will act as a sink for condensable vapours that otherwise would have been able to form sufficient supersaturation and initiate the nucleation process

Effect of High-Dose Esomeprazole on CYP1A2, CYP2C19, and CYP3A4 Activities in Humans : Evidence for Substantial and Long-lasting Inhibition of CYP2C19

In vitro, esomeprazole is a time-dependent inhibitor of CYP2C19. Additionally, racemic omeprazole induces CYP1A2 and omeprazole and its metabolites inhibit CYP3A4in vitro. In this 5-phase study, 10 healthy volunteers ingested 20 mg pantoprazole, 0.5 mg midazolam, and 50 mg caffeine as respective index substrates for CYP2C19, 3A4, and 1A2 before and 1, 25, 49 (pantoprazole only), and 73 hours after an 8-day pretreatment with 80 mg esomeprazole twice daily. The area under the plasma concentration-time curve (AUC) ofR-pantoprazole increased 4.92-fold (90% confidence interval (CI) 3.55-6.82), 2.31-fold (90% CI 1.85-2.88), and 1.33-fold (90% CI 1.06-1.68) at the 1-hour, 25-hour, and 73-hour phases, respectively, consistent with a substantial and persistent inhibition of CYP2C19. The AUC of midazolam increased up to 1.44-fold (90% CI 1.22-1.72) and the paraxanthine/caffeine metabolic ratio up to 1.19-fold (90% CI 1.04-1.36), when the index substrates were taken 1 hour after esomeprazole. Based on the recovery ofR-pantoprazole oral clearance, the turnover half-life of CYP2C19 was estimated to average 53 hours. Pharmacokinetic simulation based on the observed concentrations of esomeprazole and its metabolites as well as their published CYP2C19 inhibitory constants was well in line with the observed changes inR-pantoprazole pharmacokinetics during the course of the study. Extrapolations assuming linear pharmacokinetics of esomeprazole suggested weak to moderate inhibition at 20 and 40 mg twice daily dosing. In conclusion, high-dose esomeprazole can cause strong inhibition of CYP2C19, but only weakly inhibits CYP3A4 and leads to minor induction of CYP1A2. The enzymatic activity of CYP2C19 recovers gradually in similar to 3-4 days after discontinuation of esomeprazole treatment.Peer reviewe

Is the water footprint an appropriate tool for forestry and forest products: The Fennoscandian case

The water footprint by the Water Footprint Network (WF) is an ambitious tool for measuring human appropriation and promoting sustainable use of fresh water. Using recent case studies and examples from water-abundant Fennoscandia, we consider whether it is an appropriate tool for evaluating the water use of forestry and forest-based products. We show that aggregating catchment level water consumption over a product life cycle does not consider fresh water as a renewable resource and is inconsistent with the principles of the hydrologic cycle. Currently, the WF assumes that all evapotranspiration (ET) from forests is a human appropriation of water although ET from managed forests in Fennoscandia is indistinguishable from that of unmanaged forests. We suggest that ET should not be included in the water footprint of rain-fed forestry and forest-based products. Tools for sustainable water management should always contextualize water use and water impacts with local water availability and environmental sensitivity

UGT1A3 and Sex Are Major Determinants of Telmisartan Pharmacokinetics-A Comprehensive Pharmacogenomic Study

To investigate how variability in multiple pharmacokinetic genes associates with telmisartan exposure, we determined telmisartan single-dose (40 mg) pharmacokinetics and sequenced 379 genes in 188 healthy volunteers. IntronicUGT1Avariants showed the strongest associations with the area under the plasma concentration-time curve from zero hours to infinity (AUC(0-infinity)) and peak plasma concentration (C-max) of telmisartan. These variants were strongly linked with the increased functionUGT1A3*2allele, suggesting that it is the causative allele underlying these associations. In addition, telmisartan plasma concentrations were lower in men than in women. TheUGT1A3*2was associated with a 64% and 63% reduced AUC(0-infinity)of telmisartan inUGT1A3*2heterozygous and homozygous men, respectively (P = 1.21 x 10(-16)and 5.21 x 10(-8)). In women,UGT1A3*2heterozygosity and homozygosity were associated with 57% (P = 1.54 x 10(-11)) and 72% (P = 3.31 x 10(-15)) reduced AUC(0-infinity), respectively. Furthermore, a candidate gene analysis suggested an association ofUGT1A3*3and theSLCO1B3c.767G>C missense variant with telmisartan pharmacokinetics. A genotype score, which reflects the effects of sex and genetic variants on telmisartan AUC(0-infinity), associated with the effect of telmisartan on diastolic blood pressure. These data indicate that sex and UGT1A3 are major determinants and suggest a role for OATP1B3 in telmisartan pharmacokinetics.Peer reviewe

Explicitly accounting for needle sugar pool size crucial for predicting intra-seasonal dynamics of needle carbohydrates delta O-18 and delta C-13

We explore needle sugar isotopic compositions (delta O-18 and delta C-13) in boreal Scots pine (Pinus sylvestris) over two growing seasons. A leaf-level dynamic model driven by environmental conditions and based on current understanding of isotope fractionation processes was built to predict delta O-18 and delta C-13 of two hierarchical needle carbohydrate pools, accounting for the needle sugar pool size and the presence of an invariant pinitol pool. Model results agreed well with observed needle water delta O-18, delta O-18 and delta C-13 of needle water-soluble carbohydrates (sugars + pinitol), and needle sugar delta C-13 (R-2 = 0.95, 0.84, 0.60, 0.73, respectively). Relative humidity (RH) and intercellular to ambient CO2 concentration ratio (C-i/C-a) were the dominant drivers of delta O-18 and delta C-13 variability, respectively. However, the variability of needle sugar delta O-18 and delta C-13 was reduced on diel and intra-seasonal timescales, compared to predictions based on instantaneous RH and C-i/C-a, due to the large needle sugar pool, which caused the signal formation period to vary seasonally from 2 d to more than 5 d. Furthermore, accounting for a temperature-sensitive biochemical O-18-fractionation factor and mesophyll resistance in C-13-discrimination were critical. Interpreting leaf-level isotopic signals requires understanding on time integration caused by mixing in the needle sugar pool.Peer reviewe

Could continuous cover forestry be an economically and environmentally feasible management option on drained boreal peatlands?

Environmental and economic performance of forestry on drained peatlands was reviewed to consider whether continuous cover forestry (CCF) could be a feasible alternative to even-aged management (EM). CCF was regarded feasible particularly because continuously maintaining a tree stand with significant transpiration and interception capacity would decrease the need for ditch network maintenance. Managing CCF forests in such a way that the ground water levels are lower than in clear-cut EM forests but higher than in mature EM forests could decrease greenhouse gas emissions and negative water quality impacts caused both by anoxic redox reactions and oxidation and mineralization of deep peat layers. Regeneration studies indicated potential for satisfactory natural regeneration under CCF on drained peatlands. An economic advantage in CCF over EM is that fewer investments are needed to establish the forest stand and sustain its growth. Thus, even if the growth of trees in CCF forests were lower than in EM forests, CCF could at least in some peatland sites turn out to be a more profitable forest management regime. An advantage of CCF from the viewpoint of socially optimal forest management is that it plausibly reduces the negative externalities of management compared to EM. We propose that future research in drained peatland forests should focus on assessing the economic and environmental feasibility of CCF.Peer reviewe

Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure technigues

Peer reviewe

Effect of High-Dose Esomeprazole on CYP1A2, CYP2C19, and CYP3A4 Activities in Humans: Evidence for Substantial and Long-lasting Inhibition of CYP2C19

In vitro, esomeprazole is a time-dependent inhibitor of CYP2C19. Additionally, racemic omeprazole induces CYP1A2 and omeprazole and its metabolites inhibit CYP3A4in vitro. In this 5-phase study, 10 healthy volunteers ingested 20 mg pantoprazole, 0.5 mg midazolam, and 50 mg caffeine as respective index substrates for CYP2C19, 3A4, and 1A2 before and 1, 25, 49 (pantoprazole only), and 73 hours after an 8-day pretreatment with 80 mg esomeprazole twice daily. The area under the plasma concentration-time curve (AUC) ofR-pantoprazole increased 4.92-fold (90% confidence interval (CI) 3.55-6.82), 2.31-fold (90% CI 1.85-2.88), and 1.33-fold (90% CI 1.06-1.68) at the 1-hour, 25-hour, and 73-hour phases, respectively, consistent with a substantial and persistent inhibition of CYP2C19. The AUC of midazolam increased up to 1.44-fold (90% CI 1.22-1.72) and the paraxanthine/caffeine metabolic ratio up to 1.19-fold (90% CI 1.04-1.36), when the index substrates were taken 1 hour after esomeprazole. Based on the recovery ofR-pantoprazole oral clearance, the turnover half-life of CYP2C19 was estimated to average 53 hours. Pharmacokinetic simulation based on the observed concentrations of esomeprazole and its metabolites as well as their published CYP2C19 inhibitory constants was well in line with the observed changes inR-pantoprazole pharmacokinetics during the course of the study. Extrapolations assuming linear pharmacokinetics of esomeprazole suggested weak to moderate inhibition at 20 and 40 mg twice daily dosing. In conclusion, high-dose esomeprazole can cause strong inhibition of CYP2C19, but only weakly inhibits CYP3A4 and leads to minor induction of CYP1A2. The enzymatic activity of CYP2C19 recovers gradually in similar to 3-4 days after discontinuation of esomeprazole treatment

Dynamic forest trafficability prediction by fusion of open data, hydrologic forecasts and harvester-measured data

FOTETRAF project: www.luke.fi/projektit/fotetraf-sa-paatos-295337. Posteri esillä Marcus Wallenberg-palkintoseremonian yhteydessä pidettävässä nuorten tutkijoiden seminaarissa 26-27.10.2017 Tukholmassa (http://www.mwp.org/yr/).201

Suomen LULUCF-sektorin 2021–2025 velvoitteen toteutuminen

Tämä työ on tehty Luonnonvarakeskuksessa Maa- ja metsätalousministeriön toimeksiannosta. Toimeksianto oli: Laaditaan selvitys syistä, miksi vuotta 2021 koskevissa kasvihuonekaasuinventaarion pikaennakkotiedoissa, jotka julkistettiin 06/2022, maankäyttösektori oli muuttunut päästölähteeksi, ja mitä se tarkoittaa 2021–2025 EU LULUCF-velvoitteen toteutumisen osalta. Ilmasto- ja energiaministeriryhmä tarkastelee selvityksen pohjalta tarvittavia lisätoimia. Toimeksiantoa tarkennettiin siten, että vuoden 2021 tilannetta tarkasteltiin käyttäen kasvihuonekaasuinventaarion ennakkotietoja LULUCF-sektorin päästöistä ja poistumista (14.12.2022) pikaennakkotietojen sijaan. 1. Vuoden 2021 kasvihuonekaasuinventaarion ennakontiedon mukaan LULUCF-sektorin nielujen muuttuminen päästöksi johtuu puuston kasvun ja poistuman erotuksen pienenemisestä lisääntyneiden hakkuiden ja alentuneen kasvun vuoksi. Metsät ovat edelleen nettonielu, mutta se oli laskenut niin alhaiseksi, ettei se kata muiden maankäyttöluokkien päästöjä. 2. Mäntymetsien ikärakenne on kehittynyt siten, että kasvu alenee. Metsien ikärakenne, kaikki puulajit huomioiden, selittää noin viidenneksen VMI12:n ja VMI13:n välillä havaitusta 4,5 miljoonan kuutiometrin kasvun alenemasta. Ikärakenteen puolesta puuston kasvu todennäköisesti pysyy nykyisellä tasolla tai voi edelleen hieman alentua lähivuosina. 3. Männyllä on ollut kolme heikkoa kasvukautta (2018–2020). Etelä-Suomessa nämä kasvukaudet ovat olleet poikkeuksellisen kuivia. Pohjois-Suomessa vain kasvukausi 2018 oli poikkeuksellisen kuiva, mutta vuosien 2019 ja 2020 kasvuntasoa on Pohjois-Suomessa heikentänyt männyn voimakas käpytuotanto. Useamman vuoden heikot kasvukaudet eivät ole todennäköisiä, mutta vaikka lähivuosina kasvukaudet olisivat keskimääräistä parempia, vuosien 2018–2020 heikompi männyn kasvu säilyy VMI13:n kasvutuloksissa. Nykyisellä hakkuiden tasolla kasvu voi lähivuosina nousta vain, jos ympäristötekijät (kasvukauden pituus, lämpösumma, sademäärä) ovat suotuisat. 4. Kasvihuonekaasuinventaarion ennakkotietojen mukaan tililuokan hoidettu metsämaa, sisältäen puutuotteet, hiilinielu oli -11,4 milj. t CO2-ekv., kun metsien vertailutaso kaudelle 2021–2025 on -29,4 milj. t CO2-ekv. vuodessa. Vertailutasoon tullaan tekemään inventaarion ja vertailutasolaskennan menetelmäeroista johtuvia teknisiä korjauksia. 5. Muussa maankäytössä ei arvioida tapahtuvan merkittäviä kauden 2021–2025 laskentatulokseen vaikuttavia muutoksia. Tämä koskee erityisesti EU-LULUCF-tilinpitoa. Vaikka maatalousmaihin kohdistuvat kosteikkotoimenpiteet muuttaisivat alueen maankäytön pois maataloudesta, tilinpidossa se tulee pysymään tililuokissa hoidettu viljelysmaa tai hoidettu ruohikkoalue. Metsityksen lisäämiseksi tehtävät toimet tulevat aikanaan vaikuttamaan hoidetun metsämaan nieluun enemmän kuin tililuokkaan metsitetyt alueet. Metsäkatoa ehkäisevien toimien vaikutus sen sijaan olisi välitön, mutta suunnitellut toimet eivät ennätä vaikuttaa vuosiin 2021–2025. 6. Vuoden 2022 teollisuuspuun hakkuut olivat lokakuun loppuun mennessä 3 prosenttia alemmat kuin vuonna 2021, mutta loppuvuoden 2022 aikana hakkuiden kokonaismäärä voi saavuttaa vuoden 2021 tason. Kotimaisen puun käyttö on lisääntynyt ja lisääntynee lähivuosina edelleen teollisuuden uusien investointipäätösten sekä Venäjältä tapahtuneen puuntuonnin loppumisen myötä. Tämän selvityksen pohjalta arvioidaan, että metsien hiilinielu kaudella 2021–2025 jää 50–100 miljoonaa CO2-ekvivalentti-tonnia pienemmäksi kuin vertailutaso. Arvio ei sisällä vertailutasoon tehtävien ns. teknisten korjausten vaikutusta. 7. Metsien hiilinielun aleneminen vaikeuttaa LULUCF-sektorin velvoitteen saavuttamista kaudella 2021–2025. Toteutuneen metsänielun ollessa 50–100 miljoonaa CO2-ekvivalenttitonnia ja muusta maankäytöstä aiheutuvien päästöjen ollessa nykytasolla, joudutaan metsäjouston ja Suomen erillisjouston lisäksi hankkimaan puuttuvat yksiköt muilta jäsenmailta tai kompensoimaan taakanjakosektorin yksiköillä. Tässä selvityksessä tarve arvioidaan noin 50–80 miljoonaan CO2-ekvivalenttitonnin suuruiseksi