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Biogenic volatile organic compound (BVOC) emissions from trees subjected to biotic stress are higher compared to healthy trees, and they may also have a different compound composition. This in turn affects atmospheric chemistry and can lead to either positive or negative feedback to the climate. Climate change favors the abundance of the European spruce bark beetle (Ips typographus) which attacks the bark of Norway spruce (Picea abies) trees, causing induced BVOC emissions from the trees as a response to the insect stress. Here, results are reported from a study analyzing the difference in emission rates between healthy and bark-beetle-infested Norway spruce trees, changes in emission rates over time since the infestation started, and differences in emission rates from bark-beetle-drilled entry and exit holes. Bark chamber measurements on both healthy and infested trees were performed during the summer of 2019 at Hyltemossa and Norunda research stations in Sweden. The measurements showed that induced BVOC emissions following the bark beetle infestation were dominated by entry hole emissions in the early growing season and exit hole emissions in the later season. The results showed a significant difference in emission rates between healthy and infested trees during both seasons. The seasonal average standardized BVOC emission rate of healthy trees was 32 ± 52 µg m−2 h−1 (mean ± standard deviation), while the average standardized BVOC emission rates of infested trees were 6700 ± 6900 and 2000 ± 1300 µg m−2 h−1 during the early and late season respectively. BVOC emission rates were highest at the start of the infestation and decreased exponentially with time, showing induced emission rates for up to 1 year after which the emission rates were similar to those from healthy bark. Constitutive needle emission rates from healthy trees were found to be 11 times higher than bark emissions from healthy trees. However, when Norway spruce trees were infested, the bark emission rates were instead 6 to 20 times higher than the needle emissions, causing substantial increases in the total tree BVOC emission rate. This could lead to high impacts on atmospheric processes, specifically the formation of secondary organic aerosols, which have a higher yield from some monoterpene compounds, which increased from infested trees.

Wildfires have been effectively suppressed in the managed boreal forests of Fennoscandia for over a century. However, recent extremely hot and dry summers have highlighted the vulnerability of these forests to increasing wildfire frequency as a result of climate change. The carbon stored by managed forests plays a key role in many national climate mitigation strategies and more data is needed to assess how forest management shapes the carbon balance of these forests, including those recovering from wildfire. We established two eddy covariance towers in the area burnt by the Ljusdal fire, which affected over 9000 ha during the extreme 2018 wildfire season in Sweden. The two towers measured CO2 fluxes during the first four growing seasons after the fire at two Pinus sylvestris stands with contrasting fire impacts and forest management schemes. At one site, a mature stand had survived low severity fire but was then salvage-logged and reseeded (6 months after the fire), whilst the other site represented a young stand that was killed by high severity fire and replanted with Pinus sylvestris seedlings (2 years after the fire). After the fire, both sites were net CO2 sources at the annual scale. However, the site with dead young trees and replanted seedlings showed a faster recovery towards becoming a CO2 sink, with days of net CO2 uptake during the peak of the growing season three years after the fire. Preliminary results suggest that similar magnitudes of carbon were emitted as CO2 in the first 4 years after the fire compared to the carbon emitted during the fire itself, underlining the importance of monitoring forest CO2 fluxes and the impacts of management decisions during the initial post-fire years.

AIMS: Clinicians and regulatory authorities are placing increasing emphasis on health-related quality of life (HRQoL) and health utilities when evaluating therapeutic efficacy of new agents. We assessed health utility values in the Semaglutide Treatment Effect in People with obesity (STEP) trials.MATERIALS AND METHODS: The STEP 1-4 phase 3a, 68-week, double-blind randomized controlled trials assessed the efficacy and safety of semaglutide 2.4 mg versus placebo in individuals with BMI ≥30 kg/m2 or BMI ≥27 kg/m2 and ≥1 co-morbidity (STEP 1, 3 and 4), or BMI ≥27 kg/m2 and type 2 diabetes (STEP 2). Patients received lifestyle intervention plus intensive behavioural therapy in STEP 3. HRQoL was assessed using the Short Form 36-item Health Survey version 2 (SF-36v2) at baseline and week 68. Scores were converted into Short Form Six-Dimension version 2 (SF-6Dv2) utility scores or mapped onto the European Quality of Life Five-Dimension Three-Level (EQ-5D-3L) utility index using UK health utility weights.RESULTS: At week 68, semaglutide 2.4 mg was associated with minor health utility score improvements from baseline (all trials), while scores for placebo typically decreased. SF-6Dv2 treatment differences by week 68 for semaglutide versus placebo were significant in STEP 1 and 4 (p≤0.001), but not STEP 2 or 3. EQ-5D-3L treatment differences by week 68 for semaglutide versus placebo were significant in STEP 1, 2 and 4 (pCONCLUSIONS: Semaglutide 2.4 mg was associated with improvement in health utility scores compared with placebo, reaching statistical significance in STEP 1, 2 and 4. This article is protected by copyright. All rights reserved.

Purpose The correlation between body mass index (BMI) and utility in patients with overweight or obesity was assessed using health-related quality of life (HRQoL) data collected in two weight-loss interventional studies, SCALE and STEP 1. Methods Short-Form Health Survey 36-Item (SF-36) scores from SCALE and STEP 1 were mapped to EuroQoL-5 dimensions-3 levels (EQ-5D-3L) using an established algorithm to derive utilities for the UK. SF-36 scores from STEP 1 were converted into Short-Form six-dimensions (SF-6D) utilities for Portugal, using the tool developed by the University of Sheffield. Correlations between utility scores and BMI at baseline were assessed by multiple linear regression analyses, controlling for demographic and clinical parameters. Results Higher baseline BMI was correlated with lower EQ-5D-3L/SF-6D utilities in all analyses, although the correlation was nonsignificant. Assuming linearity between BMI ranges 30–40 kg/m2, a unit increase predicted a utility loss of − 0.0041 and − 0.0031 on EQ-5D-3L for males and females, respectively, in SCALE, − 0.0039 and − 0.0047 in STEP 1, and − 0.0027 and − 0.002 on SF-6D males and females, respectively. Presence of hypertension and older age were significantly negatively correlated with SCALE EQ-5D-3L. Age, presence of coronary artery diseases (CADs) and previous smoking were significantly negatively correlated with STEP 1 EQ-5D-3L. Only presence of CADs was significantly negatively correlated with STEP 1 SF-6D. Males had significantly higher utilities compared with females in the UK analyses. Conclusion These findings are useful to inform cost-effectiveness analyses in obesity whereby multiple factors, along with BMI, are used to calculate quality-adjusted life-years.

Emissions of biogenic volatile organic compound (BVOC) from the bark of Norway spruce (Picea abies) trees can be affected by stress, such as infestation of spruce bark beetles (Ips typographus). We studied the difference in emission rates from healthy spruce bark and infested spruce bark, the influence of time since spruce bark beetle infestation started and the difference in emission rates from bark beetle drilled entry holes and exit holes. Bark chamber measurements on both healthy trees and infested trees were performed during the summer of 2019 at two sites in Sweden. To consider the seasonal pattern of the spruce bark beetle, we divided the emission rates from infested trees into two seasons, an early season dominated by entry holes and a late season with mainly exit holes. Our findings show a significant difference in emission rates from healthy and infested trees, independent of season. The seasonal average standardized emission rate from healthy trees was 31.89 ± 51.67 μg m-2 h-1 (mean ± standard deviation), while the average standardized emission rates from infested trees were 6385 μg m-2 h-1 and 2102 μg m-2 h-1 during early and late season respectively. We also found an exponentially decreasing relationship with BVOC emission rates and time since infestation started where the emission rates reached the same level as the constitutive BVOC emission rates from bark after around one year. When comparing bark monoterpene BVOC emission rates with emission rates from needles, we found that the constitutive needle emission rates were 11 times higher than the constitutive bark emissions. However, the emission rates from infested Norway spruce tree bark were instead 6 to 20 times higher than the constitutive needle emissions, causing substantial increases in the total tree BVOC emission rate (550 % to 1900 % increase). This study adds evidence that spruce bark beetle induced bark BVOC emissions are higher than previously thought and highlights the need for further research with more samples more frequently throughout the season to fully understand the impact, which is required to quantify spruce bark beetle infestations impacts on the atmospheric chemistry and climate change.

The effect of once-weekly s.c. semaglutide 2.4 mg (sema) on the risk of developing T2D in people with obesity is unknown. Weight management with sema vs. PBO plus diet/exercise was assessed in participants (pts) with overweight/obesity in STEP 1 (68 wks) and STEP 4 (20-wk run-in on sema, 48-wk randomized withdrawal) . The 10-yr T2D risk was calculated post hoc using Cardiometabolic Disease Staging (CMDS) , a validated Bayesian logistic regression of T2D risk factors. Risk scores decreased after 68 wks from 18% to 7% with sema, and 18% to 16% with PBO (61% vs. 13% reduction [p In summary, treatment with sema reduces the 10-yr risk of T2D by ∼60% regardless of initial glycemic status, with sustained treatment required to maintain this benefit. These data suggest sema could help prevent T2D in people with obesity. Disclosure W. Garvey: Other Relationship; Boehringer Ingelheim International GmbH, Eli Lilly and Company, Epitomee, JAZZ Pharmaceuticals, Novo Nordisk, Novo Nordisk, Pfizer Inc., Pfizer Inc. T. Holst-hansen: Employee; Novo Nordisk A/S, Stock/Shareholder; Novo Nordisk A/S. P. N. Laursen: Employee; Novo Nordisk A/S. A. R. Rinnov: Employee; Novo Nordisk. L. J. Wilkinson: Employee; Novo Nordisk. Funding Novo Nordisk A/S

Infected cells communicate through secreted signaling molecules like cytokines, which carry information about pathogens. How differences in cytokine secretion affect inflammatory signaling over space and how responding cells decode information from propagating cytokines are not understood. By computationally and experimentally studying NF-κB dynamics in cocultures of signal-sending cells (macrophages) and signal-receiving cells (fibroblasts), we find that cytokine signals are transmitted by wave-like propagation of NF-κB activity and create well-defined activation zones in responding cells. NF-κB dynamics in responding cells can simultaneously encode information about cytokine dose, duration, and distance to the cytokine source. Spatially resolved transcriptional analysis reveals that responding cells transmit local cytokine information to distance-specific proinflammatory gene expression patterns, creating "gene expression zones." Despite single-cell variability, the size and duration of the signaling zone are tightly controlled by the macrophage secretion profile. Our results highlight how macrophages tune cytokine secretion to control signal transmission distance and how inflammatory signaling interprets these signals in space and time., Science Advances, 8 (35), ISSN:2375-2548

Tree killing by spruce bark beetles (Ips typographus) is one of the main disturbances to Norway spruce (Picea abies) forests in Europe and the risk of outbreaks is amplified by climate change with effects such as increased risk of storm felling, tree drought stress and an additional generation of spruce bark beetles per year[1]. The warm and dry summer of 2018 triggered large outbreaks in Sweden, the increased outbreaks are still ongoing and affected about 8 million m3 forest in 2020[2]. This is the so far highest record of trees killed by the spruce bark beetle in a single year in Sweden[2]. In 1990-2010, the spruce bark beetle killed on average 150 000 m3 forest per year in southern Sweden[3]. Bark beetles normally seek and attack Norway spruces with lowered defense, i.e. trees that are wind-felled or experience prolonged drought stress[4]. However, as the number of bark beetle outbreaks increase, the risk of attacks on healthy trees also increase[5]. This causes a higher threat to forest industry, and lowers the possibilities to mitigate climate change in terms of potential decreases in carbon uptake if the forests die[4,5]. Norway spruce trees normally defend themselves by drenching the beetles in resin[6]. The resin in turn contains different biogenic volatile organic compounds (BVOCs), which can vary if the spruce is attacked by bark beetles or not [4,6]. The most abundant group of terpenoids (isoprene, monoterpenes and sesquiterpenes), is most commonly emitted from conifers, such as Norway spruce[7,8]. The aim of this study was to enable a better understanding of the direct defense mechanisms of spruce trees by quantifying BVOC emissions and its composition from individual trees under attackTo analyze the bark beetles’ impact on Norway spruce trees a method was developed using tree trunk chambers and adsorbent tubes. This enables direct measurements of the production of BVOCs from individual trees. Three different sites in Sweden, with different environmental conditions were used for the study and samples were collected throughout the growing season of 2019. After sampling, the tubes were analyzed in a lab using automated thermal desorption coupled to a gas chromatograph and a mass spectrometer to identify BVOC species and their quantity.The preliminary results show a strong increase in BVOC emissions from a healthy tree that became infested during the data collection. The finalized results expect to enable better understanding of how spruce trees are affected by insect stress from bark beetles, and if bark beetle infestation will potentially result in increased carbon emission in the form of BVOCs.References[1] Jönsson et al. (2012). Agricultural and Forest Meteorology 166: 188–200[2] Skogsstyrelsen, (2020). https://via.tt.se/pressmeddelande/miljontals-granar-dodades-av-granbarkborren-2020?publisherId=415163&releaseId=3288473[3] Marini et al. (2017). Ecography, 40(12), 1426–1435.[4] Raffa (1991). Photochemical induction by herbivores. pp. 245-276[5] Seidl, et al. (2014). Nature Climate Change, 4(9), 806-810. [6] Ghimire, et al. (2016). Atmospheric Environment, 126, 145-152.[7] Niinemets, U. and Monson, R. (2013). ISBN 978-94-007-6606-8[8] Kesselmeier, J. and Staudt, M. (1999). Journal of Atmospheric Chemistry, 33(1), pp.23-88

The ecosystem-atmosphere flux of biogenic volatile organic compounds (BVOCs) has important impacts on tropospheric oxidative capacity and the formation of secondary organic aerosols, influencing air quality and climate. In particular, this is true in managed boreal forests in the Northern Hemisphere, where BVOC emissions often dominate over anthropogenic sources of VOC.Here we present measurements of BVOCs in a managed boreal forest located at the ICOS station Norunda in Sweden, collected using proton transfer reaction mass spectrometry (PTR-MS). This managed forest consists of a mix of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). These long-term PTR-MS measurements were collected at six heights (4m, 8.5m, 13.5m, 19m, 24.5m, and 33.5m) in the forest canopy over several periods during 2014 to 2016. Ozone concentrations were simultaneously measured in conjunction with these PTR-MS measurements. The main BVOCs investigated with the PTR-MS were isoprene, monoterpenes, methanol, acetaldehyde, and acetone. The distribution of BVOC sources and sinks in the forest canopy was explored using several Lagrangian dispersion matrix methods, including localized and continuous near-field theory. The canopy resistance and deposition velocities for ozone and the BVOCs were investigated, and the results for isoprene and monoterpene emissions were found to agree well with several standard BVOC emission algorithms. These results will have importance for constraining BVOC emission estimates from managed boreal forests in the future.

In 2018, an extreme drought affected large parts of Europe and led to the worst fire season in over a century in Sweden. We investigated the impacts of the Ljusdal fire, the largest fire complex that year, on soil CO2 and CH4 fluxes, nutrient concentrations and microclimate in a Scots pine forest. The measurements were conducted during the first growing season after the fire. In three separate analyses, we compared stands that differed in terms of burn severity (unburnt, low and high burn severity), salvage-logging (logged or unlogged) and stand age (young: 12 years old or mature: ~100 years old at the time of the fire). A mature stand affected by a high severity burn (100% tree mortality) had significantly lower soil respiration compared to a stand affected by a low severity burn (nearly 100% tree survival), but there was no difference in soil respiration between the low burn severity and unburn stands. These results indicate that autotrophic respiration plays a key role in determining post-fire soil respiration. After a high severity burn, salvage logging had no significant effects on forest soils compared to a stand where the dead trees had been left standing, although differences between these two stands are likely to become significant in the future. Stand age had a clear impact on most of the soil properties tested. Despite mean soil temperature being 5 °C warmer at a young site compared to a mature site after a high severity burn, soil respiration was lower at the young site. The young site had been clear-cut and undergone soil scarification and replanting 12 years before the fire, which is likely to have contributed to the lower nutrient availability and thinner soil organic layer there compared to the mature site. Short return intervals between disturbances such as harvesting and wildfire that remove part of the soil organic layer can thus have significant and long-term impacts on nutrient cycling and carbon exchange in the boreal forest. The boreal forest is thus vulnerable to becoming a carbon source, especially in regions where climate change is increasing the frequency of high severity wildfire and commercial timber production is expanding.

Isoprene is a highly reactive volatile organic compound emitted by vegetation, known to be a precursor of secondary organic aerosols and to enhance tropospheric ozone formation under polluted conditions. Isoprene emissions respond strongly to changes in meteorological parameters such as temperature and solar radiation. In addition, the increasing CO2 concentration has a dual effect, as it causes both a direct emission inhibition as well as an increase in biomass through fertilization. In this study we used the MEGAN (Model of Emissions of Gases and Aerosols from Nature) emission model coupled with the MOHYCAN (Model of HYdrocarbon emissions by the CANopy) canopy model to calculate the isoprene fluxes emitted by vegetation in the recent past (1979–2014) and in the future (2070–2099) over Europe at a resolution of 0.1∘×0.1∘. As a result of the changing climate, modeled isoprene fluxes increased by 1.1 % yr−1 on average in Europe over 1979–2014, with the strongest trends found over eastern Europe and European Russia, whereas accounting for the CO2 inhibition effect led to reduced emission trends (0.76 % yr−1). Comparisons with field campaign measurements at seven European sites suggest that the MEGAN–MOHYCAN model provides a reliable representation of the temporal variability of the isoprene fluxes over timescales between 1 h and several months. For the 1979–2014 period the model was driven by the ECMWF ERA-Interim reanalysis fields, whereas for the comparison of current with projected future emissions, we used meteorology simulated with the ALARO regional climate model. Depending on the representative concentration pathway (RCP) scenarios for greenhouse gas concentration trajectories driving the climate projections, isoprene emissions were found to increase by +7 % (RCP2.6), +33 % (RCP4.5), and +83 % (RCP8.5), compared to the control simulation, and even stronger increases were found when considering the potential impact of CO2 fertilization: +15 % (RCP2.6), +52 % (RCP4.5), and +141 % (RCP8.5). However, the inhibitory CO2 effect goes a long way towards canceling these increases. Based on two distinct parameterizations, representing strong or moderate inhibition, the projected emissions accounting for all effects were estimated to be 0–17 % (strong inhibition) and 11–65 % (moderate inhibition) higher than in the control simulation. The difference obtained using the two CO2 parameterizations underscores the large uncertainty associated to this effect.

Approximately 16 % of adult onset asthma is caused by occupational exposure. The need for early detection of irritant caused asthma is key in treating and preventing the progression of the disease. The aim of the work was to investigate if exposure to irritants cause change in gas composition in exhaled breath, the “exhalome”. We studied 15 female hairdressers exposed to a controlled dose of aerosolized bleach powder in a sealed climate chamber. The subjects’ self-reported symptoms, spirometry and gas components were monitored. The exhalome was collected for breath holding times of 2 and 10 seconds from central (400 ml) and peripheral lung (1500 ml), once prior to and twice after exposure. Thus, subjects were their own controls. The composition of the gas was analyzed using a Proton Transfer Reaction – Time of Flight – Mass Spectrometer (PTR-ToF-MS) where volatile organic compounds of mass up to 253 atomic mass units are identified with high time resolution. Preliminary analysis of the data shows a variation of the concentrations of the different gases in exhalome over the course of the day and that levels of isoprene and acetone are higher for longer breath holding time. More analysis is needed to evaluate if the technique is able to detect differences in the exhalome caused by the exposure. Detailed information on the relationships between the exhalome and inflammation processes in the respiratory tract induced by irritants is also required. This may contribute to a deeper understanding of asthma. In the future a PTR-ToF-MS could potentially be used as a real-time non-invasive tool for early detection asthma in exposed workers.

Disproportional warming in the northern high latitudes and large carbon stocks in boreal and (sub)arctic ecosystems have raised concerns as to whether substantial positive climate feedbacks from biogeochemical process responses should be expected. Such feedbacks occur when increasing temperatures lead, for example, to a net release of CO2 or CH4. However, temperature-enhanced emissions of biogenic volatile organic compounds (BVOCs) have been shown to contribute to the growth of secondary organic aerosol (SOA), which is known to have a negative radiative climate effect. Combining measurements in Eastern Siberia with model-based estimates of vegetation and permafrost dynamics, BVOC emissions, and aerosol growth, we assess here possible future changes in ecosystem CO2 balance and BVOC–SOA interactions and discuss these changes in terms of possible climate effects. Globally, the effects of changes in Siberian ecosystem CO2 balance and SOA formation are small, but when concentrating on Siberia and the Northern Hemisphere the negative forcing from changed aerosol direct and indirect effects become notable – even though the associated temperature response would not necessarily follow a similar spatial pattern. While our analysis does not include other important processes that are of relevance for the climate system, the CO2 and BVOC–SOA interplay serves as an example for the complexity of the interactions between emissions and vegetation dynamics that underlie individual terrestrial processes and highlights the importance of addressing ecosystem–climate feedbacks in consistent, process-based model frameworks.

Satellite derived normalized difference vegetation index (NDVI) is a common data source for monitoring regional and global ecosystem properties. In dry lands it has contributed to estimation of inter-annual and seasonal vegetation dynamics and phenology. However, due to the spectral properties of NDVI it can be affected by clouds which can introduce missing data in the time series. Remotely sensed soil moisture has in contrast to NDVI the benefit of being unaffected by clouds due to the measurements being made in the microwave domain. There is therefore a potential in combining the remotely sensed NDVI with remotely sensed soil moisture to enhance the quality and estimate the missing data. We present a step towards the usage of remotely sensed soil moisture for estimation of savannah NDVI. This was done by evaluating the European Space Agency (ESA) Climate Change Initiative (CCI) soil moisture and three of its individual products with respect to their relative performance. The individual products are from the advance scatterometer (ASCAT), Soil Moisture and Ocean Salinity (SMOS), and the Land Parameter Retrieval Model-Advanced Microwave Scanning Radiometer-Earth Observing System (LPRM-AMSR-E). Each dataset was used to simulate NDVI, which was subsequently compared to remotely sensed NDVI from MODIS. Differences in their ability to estimate NDVI indicated that, on average, CCI soil moisture differs from its individual products by showing a higher average correlation with measured NDVI. Overall NDVI modelled from CCI soil moisture gave an average correlation of 0.81 to remotely sensed NDVI which indicates its potential to be used to estimate seasonal variations in savannah NDVI. Our result shows promise for further development in using CCI soil moisture to estimate NDVI. The modelled NDVI can potentially be used together with other remotely sensed vegetation datasets to enhance the phenological information that can be acquired, thereby, improving the estimates of savannah vegetation phenology.

While emissions of many biogenic volatile organic compounds (BVOCs), such as terpenoids, have been studied quite intensively in North American and Scandinavian boreal forests, the vast Siberian boreal forests have remained largely unexplored by experimental emission studies. In this study the shoot-scale terpenoid emission rates from two mature Larix cajanderi trees growing in their natural habitat in eastern Siberia were measured at the Spasskaya Pad flux measurement site (62°15´18.4" N, 129°37´07.9" E) located on the western bank of the Lena river. The measurements were conducted during three campaigns: 3–24 June, 8–26 July, and 14–30 August, in the summer of 2009. A dynamic flow-through enclosure technique was applied for adsorbent sampling, and the samples were analysed offline with a gas chromatograph. Between 29 and 45 samples were taken from each shoot during all three campaigns. Seven different monoterpenes, six different sesquiterpenes, linalool isoprene, and 2-methyl-3-buten-2-ol (MBO) were identified. The monthly median value of the total terpenoid emissions varied between 0.006 and 10.6 μg gdw−1 h−1. The emissions were dominated by monoterpenes, which constituted between 61 and 92% of the total emissions. About half of the monoterpene emissions were comprised of Δ 3-carene; α- and β-pinene had significant emissions as well. Linalool emissions were also substantial, comprising 3–37% of the total emissions, especially in June. Sesquiterpenes accounted for less than 3% and isoprene less than 1% of the total emissions. Based on the measured emission rates, the relative atmospheric concentration of each compound was estimated. Monoterpenes were the species with the highest relative concentration, while linalool and sesquiterpenes had a notably smaller contribution to the estimated atmospheric concentration than to the emission rates. A temperature-dependent pool algorithm with a constant β (0.09 °C−1 for monoterpenes and 0.143 °C−1 for sesquiterpenes) was used to normalize the measured emission data. For monoterpenes the emission potential varied between 0.5 and 18.5 μg gdw−1 h−1 and for sesquiterpenes between 0.02 and 0.4 μg gdw−1 h−1.

English oak (Quercus robur) and European beech (Fagus sylvatica) are amongst the most common tree species growing in Europe, influencing the annual Biogenic Volatile Organic Compound (BVOC) budget in this region. Studies have shown great variability in the emissions from these tree species, originating from both genetic variability and differences in climatic conditions between study sites. In this study, we examine the emission patterns for English oak and European beech in genetically identical individuals and the potential variation within and between sites. Leaf scale BVOC emissions, net assimilation rates and stomatal conductance were measured at the International Phenological Garden sites of Ljubljana (Slovenia), Grafrath (Germany) and Taastrup (Denmark). Sampling was conducted during three campaigns between May and July 2014. Our results show that English oak mainly emitted isoprene whilst European beech released monoterpenes. The relative contribution of the most emitted compounds from the two species remained stable across latitudes. The contribution of isoprene for English oak from Grafrath and Taastrup ranged between 92–97 % of the total BVOC emissions, whilst sabinene and limonene for European beech ranged between 30.5–40.5 % and 9–15 % respectively for all three sites. The relative contribution of isoprene for English oak at Ljubljana was lower (78 %) in comparison to the other sites, most likely caused by frost damage in early spring. The variability in total leaf-level emission rates from the same site was small, whereas there were greater differences between sites. These differences were probably caused by short-term weather events and plant stress. A difference in age did not seem to affect the emission patterns for the selected trees. This study highlights the significance of within-genotypic variation of BVOC emission capacities for English oak and European beech, the influence of climatic variables such as temperature and light on emission intensities and the potential stability in relative compound contribution across a latitudinal gradient.

In this study, we present summertime concentrationsand fluxes of biogenic volatile organic compounds(BVOCs) measured at a sub-arctic wetland in northern Swedenusing a disjunct eddy-covariance (DEC) technique basedon a proton transfer reaction mass spectrometer (PTR-MS).The vegetation at the site was dominated by Sphagnum,Carex and Eriophorum spp. The measurements reportedhere cover a period of 50 days (1 August to 19 September2006), approximately one half of the growing season at thesite, and allowed to investigate the effect of day-to-day variationin weather as well as of vegetation senescence on dailyBVOC fluxes, and on their temperature and light responses.The sensitivity drift of the DEC system was assessed bycomparing H3O+-ion cluster formed with water molecules(H3O+(H2O) at m37) with water vapour concentration measurementsmade using an adjacent humidity sensor, and theapplicability of the DEC method was analysed by a comparisonof sensible heat fluxes for high frequency and DEC dataobtained from the sonic anemometer. These analyses showedno significant PTR-MS sensor drift over a period of severalweeks and only a small flux-loss due to high-frequency spectrumomissions. This loss was within the range expectedfrom other studies and the theoretical considerations. In this study, we present summertime concentrations and fluxes of biogenic volatile organic compounds (BVOCs) measured at a sub-arctic wetland in northern Sweden using a disjunct eddy-covariance (DEC) technique based on a proton transfer reaction mass spectrometer (PTR-MS). The vegetation at the site was dominated by Sphagnum, Carex and \textit{Eriophorum} spp. The measurements reported here cover a period of 50 days (1 August to 19 September 2006), approximately one half of the growing season at the site, and allowed to investigate the effect of day-to-day variation in weather as well as of vegetation senescence on daily BVOC fluxes, and on their temperature and light responses. The sensitivity drift of the DEC system was assessed by comparing H3O+-ion cluster formed with water molecules (H3O+(H2O) at m37) with water vapour concentration measurements made using an adjacent humidity sensor, and the applicability of the DEC method was analysed by a comparison of sensible heat fluxes for high frequency and DEC data obtained from the sonic anemometer. These analyses showed no significant PTR-MS sensor drift over a period of several weeks and only a small flux-loss due to high-frequency spectrum omissions. This loss was within the range expected from other studies and the theoretical considerations.Standardised (20 °C and 1000 μmol m−2 s−1 PAR) summer isoprene emission rates found in this study of 329 μg C m−2 (ground area) h−1 were comparable with findings from more southern boreal forests, and fen-like ecosystems. On a diel scale, measured fluxes indicated a stronger temperature dependence than emissions from temperate or (sub)tropical ecosystems. For the first time, to our knowledge, we report ecosystem methanol fluxes from a sub-arctic ecosystem. Maximum daytime emission fluxes were around 270 μg m−2 h−1 (ca. 100 μg C m−2 h−1), and during most nights small negative fluxes directed from the atmosphere to the surface were observed.

High latitude wetlands play an important role for the surface-atmosphere exchange of carbon dioxide (CO2) and methane (CH4), but fluxes of biogenic volatile organic compounds (BVOC) in these ecosystems have to date not been extensively studied. This is despite BVOC representing a measurable proportion of the total gaseous C fluxes at northern locations and in the face of the high temperature sensitivity of these systems that requires a much improved process understanding to interpret and project possible changes in response to climate warming. We measured emission of isoprene and photosynthetic gas exchange over two growing seasons (2005–2006) in a subarctic wetland in northern Sweden with the objective to identify the physiological and environmental controls of these fluxes on the leaf scale. The sedge species Eriophorum angustifolium and Carex rostrata were both emitters of isoprene. Springtime emissions were first detected after an accumulated diurnal mean temperature above 0°C of about 100 degree days. Maximum measured growing season standardized (basal) emission rates (20°C, 1000 μmol m−2 s−1) were 1075 (2005) and 1118 (2006) μg C m−2 (leaf area) h−1 in E. angustifolium, and 489 (2005) and 396 (2006) μg C m−2 h−1 in C. rostrata. Over the growing season, basal isoprene emission varied in response to the temperature history of the last 48 h. Seasonal basal isoprene emission rates decreased with leaf nitrogen (N), which may be explained by the typical growth and resource allocation pattern of clonal sedges as the leaves age. The observations were used to model emissions over the growing season, accounting for effects of temperature history, links to leaf assimilation rate and the light and temperature dependencies of the cold-adapted sedges.

The short-term limit value for PM10 having become effective in January 2005 was exceeded in many regions within the EU in 2005 and 2006. Therefore, strategies, particularly with respect to traffic control, are discussed, which could cause reduced PM10 concentrations leading to a more effective compliance with the short-term PM10 limit value. These strategies are often justified on PM10 differences between a roadside and an adjacent urban background station. As PM10 is a complex mixture of species originating from different sources, the working hypothesis has been posted that the meteorological exchange conditions strongly affect the PM10 concentration. Therefore, the role of the meteorological exchange conditions with respect to different PM10 patterns, like cycles and PM10 episodes, was investigated on the basis of mean daily PM10 values from air pollution monitoring stations in Baden-Wurttemberg (SW Germany) in the period January 2001 to February 2006. To characterise the meteorological exchange conditions in a spatial resolution, different meteorological variables were used. Partly, they are directly measured at the air pollution monitoring stations or, as for the height of the mixing-layer (MLH) and the stagnation index (SI), they were derived from results of the local model (LM) of the German Weather Service. For periods without precipitation, the results show a statistically significant relationship between PM10 and MLH as well as SI. PM10 increased with decreasing MLH and increasing SI. During periods with precipitation, these relationships were very weak and had no statistical significance. The analysis of the influence of precipitation performed on a daily basis revealed a distinct reduction of PM10 on the first day with precipitation after a period without precipitation. On following days without precipitation, PM10 increased again. Characteristic of the PM10 episodes analysed were remarkably reduced meteorological exchange conditions described by MLH, near-surface wind speed and precipitation. As a case study, two extreme PM10 episodes in January/February 2006 were investigated in detail. As expected, the station-specific variability of the mean daily PM10 values correlated well with daily values of MLH and SI reflecting the pattern of the regional meteorological exchange conditions. Altogether, all results of this investigation point out the main significance of the meteorological exchange conditions on the PM10 level, which is particularly dominant during PM10 episodes. (Less)

The effect of forest management (thinning) on in situ carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) trace gas exchange between soil and atmosphere was studied in three consecutive years at three beech forest sites, which differ in aspect [southwest (SW), northeast (NE), northwest (NW)]. At all sites adjacent thinning plots (“T”) and untreated control plots (“C”) were established. Measurements at the SW and NE sites covered the years 4–6 after thinning while at the NW site measurements covered the year before and the first 2 years after thinning. Mean N2O fluxes were

We assessed seasonal changes of total soluble nonprotein nitrogen compounds (TSNN) in adult European beech trees (Fagus sylvatica, L.) growing under different local climate during the growing season immediately following a thinning treatment and 3 years later. In both years, samples of leaves, xylem sap and phloem exudates from beech trees growing in thinned and unthinned (control) stands on a dry, warm SW exposed and a cooler, moist NE exposed site were collected in May, July and September. In May of both years, asparagine (Asn) and glutamine (Gln) were most abundant in leaves and xylem, respectively, whereas arginine (Arg) dominated in the phloem. In July, TSNN concentrations decreased in all tissues and sites, but differences in water availability between aspects were reflected in TSNN concentrations. In September, differences in the increase of Arg concentration in the phloem were related to differences in the onset of senescence between treatments. Thinning treatment increased amino compound concentrations of beech tissues in July on both aspects, particularly at the NE thinned site. It is supposed that, the N balance of adult beech is favoured by both, the thinning treatments as well as the cool-moist climate prevailing at the NE aspect.

Within the framework of an interdisciplinary project on the impact of climate and forest management on beech dominated deciduous forests, forest meteorological measurements are carried out within and above different beech stands (Fagus sylvatica L.) on opposite slopes of a narrow valley located in the Swabian Jura mountain range (south-west Germany). Referring to test plots on both slopes, the following cycles of radiation components are discussed: (1) Monthly mean values of transmission and extinction of global solar irradiance, photosynthetically active radiation as well as UV-A and UV-B radiation through the canopy, (2) diurnal courses of surface albedo α, net short-wave radiation K*, net long-wave radiation L* and net all-wave radiation Q* for a cloudless day in March (leafless period) and a cloudless day in July (fully-leaved period) above and below the canopy of different beech stands, and (3) monthly mean values of α, K*, L* and Q* for the same stand conditions as for (2). The results point out the combined impact on the investigated radiation components emanating from seasonally variable canopy density (quantified by the plant area index), exposure and sun elevation.

Measurements of the net radiation balance of two forested sites on the opposite slopes of a valley in south-western Germany, made over 3 years, are presented in this study. Radiation sensors were mounted horizontally on two measurement towers above two beech stands. The direct part of the measured short-wave incoming radiation was adjusted according to the slope's angle to convert horizontally measured radiation data into surface-parallel radiation fluxes. During periods when contemporaneous measurements of slope-parallel and horizontal radiation fluxes were available, the calculation of surface-parallel radiation fluxes from the horizontally recorded net radiation components were compared with measured values. The net radiative fluxes parallel to the slopes were calculated for a period of 36 months and analysed. Results show that the different aspects of both sites cause significant differences of the net radiation balance. In June, when the elevation of the sun is highest, incoming solar radiation K downward arrow received on the NE-slope was 9% lower than K downward arrow received on the SW-slope. During the winter months, the differences were much greater and incoming solar radiation to the NE-slope was 50% of that to the SW-slope. Due to the differing solar irradiance, net radiation fluxes were significantly higher on the SW-slope than on the NE-slope. For long-wave radiation only small differences between both slopes could be found. Since radiative fluxes determine the energy balance and hence the microclimate and water balance of a forest stand, these differences in the net radiation balance between the slopes are important for the vegetation.

Within the framework of an interdisciplinary project on the effects of climate and forest management on beech-dominated deciduous forests (Swabian Jura, south-western Germany), forest meteorological investigations are carried out to analyse the influences of exposure and canopy density on the microclimate within various beech stands (Fagus sylvatica L.). This second paper of the series “Microclimate within beech stands” focuses on the thermal conditions that exist mainly in the near-surface layer at different test plots. They were analysed by air temperature, T a, (at 1.5 m a.g.l) and soil temperature, T s, at six depths measured continuously in the period 1999–2003. The main results can be summarized as follows. (1) The thermal situation within the beech stands described by T a depended primarily on the turbulent air-mass exchange conditions which were based on the slope-specific energy balance of the forest floor and advective heat fluxes. (2) The thermal situation within the soil described by T s at 3 and 20 cm depth was governed by the molecular heat transport. Therefore, the heating and cooling rates of T s were always lower than for T a. Higher T a and T s values for the test plots on the SW slope showed that the thermal conditions within the beech stands depended primarily on the exposure. (3) Based on slope-specific differences of daily extremes of T a and T s at 3 cm depth between the silviculturally treated and control plots, the influence of the more pronounced height growth of the understorey vegetation under the near-surface thermal conditions could be clearly verified for the NE slope.

At eight different dates during the 2000 growing season, d d d 13 C and d 18 O were determined in the phloem of adult beech trees growing in natural beech stands in south-west Germany differing in stand density and local climate. In addition, stand transpiration, precipitation, photosynthetic active radiation, relative air humidity, water pressure deficit of the air, air and soil temperature, soil water potential, and sugar concentration of the phloem sap were determined directly and evaporation and canopy stomatal conductance were modelled. All parameters were related to d 13 C. The study aimed to identify the time integral within which the d d d 13 C of organic compounds transported in the phloem is an indicative measure of these environmental influences. d 13 C of soluble carbon transported in the phloem was well correlated with mean stomatal conductance in a two-day integral prior to phloem sampling but did not depend on either light intensity or soil water availability. A strong positive relationship between d 13 C and d 18 O pointed to observed 13

Summary • Here, the effects were assessed of local climate and canopy thinning on the carbon isotope composition (δ13C) signatures of different plant groups in the understorey of a beech (Fagus sylvatica) forest in southern Germany. The relationship between δ13C and environmental parameters, within different time integrals, was also studied. • δ13C was analysed in different tissues of beech regeneration, and herbaceous and woody understorey vegetation, in thinned and untreated control stands differing in aspect and, hence, local climate, on three dates during the growing season. • Generally, tissues were 13C-depleted on the north-east, compared with the south-west aspect. Thinning had variable effects on δ13C, depending on plant group and sampling date. δ13C in beech leaves and roots in control stands was mostly influenced by mean soil water potential in 4- and 8-wk integrals before sampling, respectively, and in leaves, additionally, by mean radiation in a 4-wk time integral. Shoot water potential and transpiration influenced foliar δ13C of beech whereas δ13C in the beech wood was modulated by soil temperature integrated over a 4-wk period before sampling. Above-ground tissues of woody and herbaceous plants were 13C-enriched in mid-summer; their δ13C was poorly related to environmental factors. • δ13C of various tissues of beech regeneration appears to be indicative of recent environmental conditions within the forest understorey and, consequently, this easy-to-determine physiological parameter could be used widely to assess effects of silvicultural treatments.

Forstmeteorologische Untersuchungen werden im sudwestlichen Teil der Schwabischen Alb (Sudwestdeutschland) durchgefuhrt, um die Einflusse von Exposition und Uberschirmung auf das Mikroklima in verschiedenen Rotbuchenbestanden (Fagus sylvatica L.) zu analysieren. Die Untersuchungen sind Bestandteil interdisziplinarer Arbeiten uber die Auswirkungen von Klima und Bewirtschaftung auf Strukturen und Prozesse in buchendominierten Laubwaldern. Grundlage der Untersuchungen bilden Bodenstationen zur kontinuierlichen Erfassung forstmeteorologischer Variablen. Sie wurden in einem engen Tal am NO- und dem gegenuberliegenden SW-Hang auf jeweils einer unbehandelten Kontrollflache und einer starken Schirmhiebflache eingerichtet. Mit Sensoren an zwei Messturmen auf den beiden unbehandelten Kontrollflachen werden zusatzlich die klimatischen Bedingungen uber den Buchenbestanden und in ihren Kronenraumen erfasst. Durch die Anlage der Versuchsflachen ist es moglich, nicht nur die expositionsbedingten Einflusse, sondern uber die Variabilitat des Pflanzenflachenindexes PAI auch die Auswirkungen von waldbaulicher Behandlung und Phanophasen auf das Mikroklima in den verschiedenen Buchenbestanden zu untersuchen. Dieser Artikel konzentriert sich auf die an den Bodenstationen und als Referenz uber den Bestanden gemessene photosynthetisch aktive Strahlung PAR. Sie wird mit horizontal orientierten Sensoren erfasst. Uber den Bestanden lassen sich Unterschiede zur hangparallelen PAR mit Modellrechnungen fur die Globalstrahlung G abschatzen, weil PAR/G uber den Bestanden nahezu konstant ist (1,937 μmol J–1). Als Ergebnisse werden fur PAR und die PAR-Interzeption im Kronenschirm im Jahr 2001 diskutiert: mittlere Tagesgange fur je einen Monat in der laubfreien und belaubten Phase, Tages- und Monatsmittelwerte uber das gesamte Jahr sowie Mittelwerte fur die laubfreie und belaubte Phase. Sie zeigen den Einfluss der Exposition beider Hange in der laubfreien Phase auf PAR an den Bodenstationen und die PAR-Interzeption auf. Er trat in der belaubten Phase deutlich gegenuber dem Einfluss des voll entwickelten Kronenschirms zuruck. Resultate aus Regressionsanalysen fur den gesamten Untersuchungszeitraum deuten mit ansteigendem PAI eine lineare Abnahme von PAR/G unter dem Kronenschirm sowie eine logarithmische Zunahme der PAR-Interzeption im Kronenschirm und eine exponentielle Abnahme der PAR-Transmission durch den Kronenschirm der Buchenbestande an. Auch beim Extinktionskoeffizienten k von PAR besteht die Tendenz einer logarithmischen Abnahme mit ansteigendem PAI.

Linked open data sets are often complex in structure and large in size. Understanding unfamiliar data is a central process when establishing trust with hitherto unknown information. Unfortunately, this can be problematic: manual inspection might be prohibitively time-intensive and would require the complete data set to be available. We propose to investigate the structure and content of data sets using a series of specific queries executed over a given SPARQL endpoint. Within the paper we first define 14 queries, motivate why we created them, and explain how they work. Subsequently, we are demonstrating the feasibility of this approach by applying the queries in the context of a real-world use case study.

We investigated atmospheric aerosol particle dynamics in a boreal forest zone in northern Scandinavia. We used aerosol number size distribution data measured with either a differential mobility particle sizer (DMPS) or scanning mobility particle sizer (SMPS) at three stations (Värriö, Pallas and Abisko), and combined these data with the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) air mass trajectory analysis. We compared three approaches: analysis of new particle formation events, investigation of aerosol particle number size distributions during the air mass transport from the ocean to individual stations with different overland transport times, and analysis of changes in aerosol particle number size distributions during the air mass transport from one measurement station to another. Aitken-mode particles were found to have apparent average growth rates of 0.6–0.7 nm h−1 when the air masses traveled over land. Particle growth rates during the new particle formation (NPF) events were 3–6 times higher than the apparent particle growth during the summer period. When comparing aerosol dynamics for different overland transport times between the different stations, no major differences were found, except that in Abisko the NPF events were observed to take place in air masses with shorter overland times than at the other stations. We speculate that this is related to the meteorological differences along the paths of air masses caused by the land surface topology. When comparing air masses traveling in an east-to-west direction with those traveling in a west-to-east direction, clear differences in the aerosol dynamics were seen. Our results suggest that the condensation growth has an important role in aerosol dynamics even when NPF is not evident.

We performed ambulatory 24-hour esophagus ECG in nine patients with dual chamber pacemakers suspect of transient arrhythmias in order to achieve correct and reliable P wave identification during daily life activities. In all patients episodes were observed with varying atrial artifact to left atrial depolarization sequences. These episodes probably reflected presence of atrial fusion systole, an ECG phenomenon which should be taken into account when analyzing ambulatory esophagus ECG. Thus, the ambulatory esophagus ECG revealed its ability to detect spontaneous atrial depolarization in the presence of pacemaker artifact in patients with DDD(R) pacemakers.

A microwave tip clearance sensor capable of measuring the hottest stages of industrial and aero gas turbines has been developed. This new microwave sensor has been integrated into a commercial package for online real-time monitoring of machine data. However, data analysis of large numbers of tip clearance probes makes standard industry graphic techniques cluttered. A method has been developed to reduce this data and visualize it in order to provide intuitive representations of the data from which a user can quickly draw the right conclusions about machine behavior. The main motivation for the development of a 3D graphical user interface is the density of information that can be shown to the user at one time. Tip clearance measurement is very data-rich, as every individual blade for each sensor mounted around the engine case is available. The result is that it may be difficult to find slight changes within hundreds of clearance trends. Only specialists with long experience in tip clearance measurement can synthesize all the data quickly enough using standard 2D plots. The 3D graphical user interface brings all of this data together to calculate the aggregated blade pattern, rotor positioning, and estimated case shape. All of these measurements are available to the user in a single visualization. Colors indicating alarm or clearance scale quickly draw attention to the most important data such as the minimum clearance point around the engine case where a rub may be likely to occur. This method is based about a case shape fitting algorithm that combines data from multiple sensors to make a case shape estimate based on fitting of a non-uniform rational B-spline (NURB). The scaling is also distorted in order to accentuate the graphics in a way that provides an intuitive understanding of the machine state. The method of applying this data accentuation is important so as to not be misleading. This innovative navigation interface presented in this paper capitalizes on modern advances in computer graphics to aid engineers and operators in understanding, access, monitoring, and analysis of tip clearance and air-gap measurements.

Aerosol particles can modify cloud properties by acting as cloud condensation nuclei (CCN). Predicting CCN properties is still a challenge and not properly incorporated in current climate models. Atmospheric particle number size distributions, hygroscopic growth factors, and polydisperse CCN number concentrations were measured at the remote subarctic Stordalen mire, 200 km north of the Arctic Circle in northern Sweden. The CCN number concentration was highly variable, largely driven by variations in the total number of sufficiently large particles, though the variability of chemical composition was increasingly important for decreasing supersaturation. The hygroscopicity of particles measured by a hygroscopicity tandem differential mobility analyzer (HTDMA) was in agreement with large critical diameters observed for CCN activation (kappa approximate to 0.07-0.21 for D = 50-200 nm). Size distribution and time- and size-resolved HTDMA data were used to predict CCN number concentrations. Agreement of predictions with measured CCN within +/- 11% was achieved using parameterized Kohler theory and assuming a surface tension of pure water. The sensitivity of CCN predictions to various simplifying assumptions was further explored: We found that (1) ignoring particle mixing state did not affect CCN predictions, (2) averaging the HTDMA data in time with retaining the size dependence did not introduce a substantial bias, while individual predictions became more uncertain, and (3) predictions involving the hygroscopicity parameter recommended in literature for continental sites (kappa approximate to 0.3 +/- 0.1) resulted in a significant prediction bias. Future modeling studies should therefore at least aim at using averaged, size-resolved, site-specific hygroscopicity or chemical composition data for predictions of CCN number concentrations. (Less)

Subarctic aerosol was sampled during July 2007 at the Abisko Research Station Stordalen field site operated by the Royal Swedish Academy of Sciences. Located in northern Sweden at 68° latitude and ...

High latitude wetlands play an important role for the surface-atmosphere exchange of carbon dioxide (CO2) and methane (CH4), but fluxes of biogenic volatile organic compounds (BVOC) in these ecosystems have to date not been extensively studied. This is despite BVOC representing a measurable proportion of the total gaseous C fluxes at northern locations and in the face of the high temperature sensitivity of these systems that requires a much improved process understanding to interpret and project possible changes in response to climate warming. We measured emission of isoprene and photosynthetic gas exchange over two growing seasons (2005–2006) in a subarctic wetland in northern Sweden with the objective to identify the physiological and environmental controls of these fluxes on the leaf scale. The sedge species Eriophorum angustifolium and Carex rostrata were both emitters of isoprene, and springtime emissions were first detected after an accumulated diurnal mean temperature above 0°C of about 100 degree days. Maximum measured growing season standardized (basal) emission rates (20°C, 1000 μmol m−2 s−1) were 1075 (2005) and 1118 (2006) μg C m−2 (leaf area) h−1 in E. angustifolium, and 489 (2005) and 396 (2006) μg C m−2 h−1 in C. rostrata. Over the growing season, basal isoprene emission varied in response to the temperature history of the last 48 h. Seasonal basal isoprene emission rates decreased also with leaf nitrogen (N), which may be explained by the typical growth and resource allocation pattern of clonal sedges as the leaves age. The observations were used to model emissions over the growing season, accounting for effects of temperature history, links to leaf assimilation rate and the light and temperature dependencies of the cold-adapted sedges.

Auffaellige Episoden erhoehter PM10-Konzentrationen sind in Baden-Wuerttemberg gehaeuft in den Winterhalbjahren anzutreffen und scheinen keinen eindeutigen Zusammenhang zum Verkehrsaufkommen zu haben. Sie zeichnen sich durch einen mehrtaegigen Konzentrationsanstieg und raschen Konzentrationsabfall aus. Offensichtlich muessen sekundaere Aerosolbildungen stattfinden. Ammoniak, Stickstoffdioxid und Schwefeldioxid sind Vorstufen zur Aerosolbildung. Ihre Quellen sind die Intensivtierhaltung, der Kraftfahrzeugverkehr und Kraftwerke. Im Rahmen der Untersuchung wurden die PM10-Fraktion von Schwebestaub und die Staubinhaltsstoffe (Kohlenstoff, loesliche Anionen und Kationen) bestimmt. Bei der Staubepisode vom Februar 2005 ist ein eindeutiger Zusammenhang mit steuernden meteorologischen Parametern zu erkennen. Die Wettersituation laesst sich als typische winterliche Lage mit einem Hochdruckgebiet ueber Osteuropa, sehr schwachen Druckgradienten und starker bodennaher Inversion kennzeichnen. Ostwinde und hohe Sonneneinstrahlung haben die Ammoniakemissionen erhoeht. Hohe Lufttemperaturen, hohe relative Feuchten und langsame Windgeschwindigkeiten haben die Aerosolbildung beguenstigt. Die Transportrichtungen fuehrten ueber Gebiete mit Intensivtierhaltung. Ein herannahendes Atlantiktief hat die Inversionslage wieder aufgeloest und die PM10-Konzentration gesenkt. Die Staubzusammensetzung hat sich waehrend der Episode geaendert. Ammonium und Nitrat haben im Verhaeltnis zu Russ stark zugenommen. Nach der Episode erfolgte ein Konzentrationsausgleich. Mit Hilfe eines Emissionskatasters wird versucht, die Menge gebildeten Aerosols im Stadtgebiet Stuttgarts theoretisch abzuschaetzen. Es laesst sich zeigen, dass 1. die Aerosolbildung durch Verkehrsemissionen moeglich ist; 2. ein starker regionaler Einfluss von aussen auf die Stadtgebiete vorhanden ist; 3. staedtische Effekte (Strassenschluchteffekt) ergaenzend wirken; 4. laendliche Ammoniakquellen (Intensivtierhaltung) auch im Winter bei entsprechender Wetterlage aktiv sind; 5. die Mischungsschichthoehe ein stark steuernder meteorologischer Parameter ist. Zur eindeutigen Beurteilung der Aerosolbildung fehlen theoretische und messtechnische Daten. Die zum Aerosolanstieg beitragenden Faktoren sind noch zu klaeren. Durch Modellierungen sollen Partikelbildungszeiten abgeschaetzt werden. Winterbedingungen und Stroemungsverhaeltnisse in Strassenschluchten sollen beruecksichtigt werden.

*The largest barrier to effective operation of tip clearance sensors in aero engines has been survivability and sensor accuracy within difficult thermal environments, especially in the turbine area. Thermal cycling, high thermal gradients and total time at temperature often contribute to premature sensor degradation and failure. This paper describes the results of testing a microwave tip clearance sensor designed to operate within either the compressor or turbine. The testing included resolution and linearity measurements along with thermal cycling of the cable in a high temperature furnace. I. Introduction HE measurement of tip clearance within gas turbine engines is normally performed within the context of providing information back to engine designers. It is desired that tip clearances be designed as close as possible, yet still not rub the case as the engine goes through its operating envelope. It has been documented that tip clearance pinch points occur on takeoff and landing as differences in thermal expansions between the case and rotor occur during the full output power condition at takeoff as well as the thermal soak back that occurs immediately after landing. 1 It is difficult to obtain actual tip clearance data in the field, due to the difficulty in getting tip clearances sensors to provide accurate and reliable data for an extended period of time. Therefore, design tip clearances can often be conservative, since it normally desirable to operate at a larger clearance then risk significant mechanical contact between the blades and case. Large tip clearances can have a substantial impact on efficiencies. It has been reported in the literature that a 0.001” the tip clearance can be closed can contribute as much as an additional 0.1% in efficiency improvement. 2 Normal operation of the engine typically causes clearances to increase over time as the blades and case coatings gradually erode due to the gas path or mechanical contact between the blades and case. If an active clearance control system could be designed able to adjust the tip clearances dynamically for the current engine condition, then the clearances could be optimized for the current location within the operating envelope as well as assist in maintaining constant engine performance in-between overhauls. A variety of active tip clearance control methods have been proposed including thermal techniques that control the clearance using compressor bleed air as well as active mechanical techniques that shift the rotor axially or use some type of segmented case to squeeze the case around the blades. New large commercial engine designs use compressor bleed air to actively control the tip clearance. Due to the inability to directly measure clearances in the engine, the tip clearance is scheduled using available data off of the engine combined with various models and algorithms. This technique also has some conservatism within it, which would benefit from actual clearance data to close the loop and thus optimize the control system. To date, the main types of sensors that are used for measuring tip clearance include capacitive, eddy current, optical, and microwave. Each of these different sensing principals has positives and negatives associated with them. The largest barrier to date in implementing a tip clearance sensor on a production engine has been sensor reliability, especially in the hottest areas of the engine. Sensor reliability in the turbine will typically be tens to hundreds of hours without some type of external active cooling, such as nitrogen or circulated water. Therefore, the ability to implement a sensor with long term reliability remains the most significant barrier to improved active clearance control performance. The microwave sensor described in this paper contains some unique characteristics, which make it highly suitable for use in the turbine environment. This paper will describe those characteristics as well as provide the results of performance testing showing the applicability of the sensor for use within an active clearance control system.

For some beech ( Fagus sylvatica L.) stands with different stand densities the plant area index (PAI) was measured by means of a Licor LAI-2000 plant canopy analyser. The stands are located on the slopes of a valley in south-west Germany and had been treated by different types of silvicultural management (heavy shelterwood felling, light shelterwood felling, control plot). The analyser was used (a) to investigate the light conditions on plots of the same thinning regime, (b) to quantify the differences between the different treatments and (c) to obtain absolute values of PAI for interdisciplinary research. PAI was measured at three different phenological stages (leafless, leaf-unfolding and fully leafed season in 2000) and was found to be about 5.2 for the fully developed canopy on the control plots, 3.2 on the light fellings and about 2.0 for the heavy fellings. In the leafless period PAI was between 1.1 (control) and 0.4 (heavy felling). Measurements made in summer 2000 and summer 2002 were compared, and showed an increase of PAI, especially on the thinned plots. Measurements of photosynthetically active radiation (PAR) above and below the canopy in combination with measured PAI were used to apply Beer's Law of radiation extinction to calculate the extinction coefficient k for different sky conditions and for the different growing seasons on the control plots. The extinction coefficient k for the beech stands was found to be between 0.99 and 1.39 in the leafless period, 0.62 to 0.91 during leaf unfolding and between 0.68 and 0.83 in the fully leafed period. Using PAR measurements and the k values obtained, the annual cycle of PAI was modelled inverting Beer's Law.

Bacterial mineralisation of four sulfonylurea herbicides at 20 microg kg(-1) in a sandy soil from nine different depths in a sandy soil horizon (5-780 cm) was investigated in laboratory studies. Metsulfuron-methyl, chlorsulfuron, and tribenuron-methyl were 14C-labelled in the sulfonamide ring, while thifensulfuron-methyl was labelled in the thiophene ring. The highest mineralised amount in 126 days was observed for metsulfuron-methyl (40%) followed by tribenuron-methyl (25%), and thifensulfuron-methyl (11%). Chlorsulfuron showed low mineralisation in all the soils tested (

The influence of atmospheric exchange conditions on near-surface PM 10 concentrations is analysed for four cities in the South-West of Germany in the period from 2001 to 2005. For each city, the PM 10 data originates from roadside stations and Urban Background (UB) stations, that is, two types of official urban air quality monitoring stations characterised by different emission situations. The atmospheric exchange conditions are represented by solar radiation, air temperature, wind speed, mixing-layer height, precipitation and backward-trajectories. The results of the statistical analysis indicate that

Allele number, or zygosity, is a clear determinant of gene expression in diploid cells. However, the relationship between the number of copies of a gene and its expression can be hard to anticipate, especially when the gene in question is embedded in a regulatory circuit that contains feedback. Here, we study this question making use of the natural genetic variability of human populations, which allows us to compare the expression profiles of a receptor protein in natural killer cells among donors infected with human cytomegalovirus with one or two copies of the allele. Crucially, the distribution of gene expression in many of the donors is bimodal, which indicates the presence of a positive feedback loop somewhere in the regulatory environment of the gene. Three separate gene-circuit models differing in the location of the positive feedback loop with respect to the gene can all reproduce the homozygous data. However, when the resulting fitted models are applied to the hemizygous donors, one model (the one with the positive feedback located at the level of gene transcription) is superior in describing the experimentally observed gene-expression profile. In that way, our work shows that zygosity can help us relate the structure and function of gene regulatory networks.