Surface and boundary layer exchanges of volatile organic compounds, nitrogen oxides and ozone during the GABRIEL campaign

We present an evaluation of sources, sinks and turbulent transport of nitrogen oxides, ozone and volatile organic compounds (VOC) in the boundary layer over French Guyana and Suriname during the October 2005 GABRIEL campaign by simulating observations with a single-column chemistry and climate model (SCM) along a zonal transect. Simulated concentrations of O3 and NO as well as NO2 photolysis rates over the forest agree well with observations when a small soil-biogenic NO emission flux was applied. This suggests that the photochemical conditions observed during GABRIEL reflect a pristine tropical low-NOx regime. The SCM uses a compensation point approach to simulate nocturnal deposition and daytime emissions of acetone and methanol and produces daytime boundary layer mixing ratios in reasonable agreement with observations. The area average isoprene emission flux, inferred from the observed isoprene mixing ratios and boundary layer height, is about half the flux simulated with commonly applied emission algorithms. The SCM nevertheless simulates too high isoprene mixing ratios, whereas hydroxyl concentrations are strongly underestimated compared to observations, which can at least partly explain the discrepancy. Furthermore, the model substantially overestimates the isoprene oxidation products methlyl vinyl ketone (MVK) and methacrolein (MACR) partly due to a simulated nocturnal increase due to isoprene oxidation. This increase is most prominent in the residual layer whereas in the nocturnal inversion layer we simulate a decrease in MVK and MACR mixing ratios, assuming efficient removal of MVK and MACR. Entrainment of residual layer air masses, which are enhanced in MVK and MACR and other isoprene oxidation products, into the growing boundary layer poses an additional sink for OH which is thus not available for isoprene oxidation. Based on these findings, we suggest pursuing measurements of the tropical residual layer chemistry with a focus on the nocturnal depletion of isoprene and its oxidation products

Flux estimates of isoprene, methanol and acetone from airborne PTR-MS measurements over the tropical rainforest during the GABRIEL 2005 campaign

Tropical forests are a strong source of biogenic volatile organic compounds (BVOCs) to the atmosphere which can potentially impact the atmospheric oxidation capacity. Here we present airborne and ground-based BVOC measurements representative for the long dry season covering a large area of the northern Amazonian rainforest (6-3° N, 50-59° W). The measurements were conducted during the October 2005 GABRIEL (Guyanas Atmosphere-Biosphere exchange and Radicals Intensive Experiment with the Learjet) campaign. The vertical (35 m to 10 km) and diurnal (09:00-16:00) profiles of isoprene, its oxidation products methacrolein and methyl vinyl ketone and methanol and acetone, measured by PTR-MS (Proton Transfer Reaction Mass Spectrometry), have been used to empirically estimate their emission fluxes from the forest canopy on a regional scale. The mixed layer isoprene emission flux, inferred from the airborne measurements above 300 m, is 5.7 mg isoprene m-2 h-1 after compensating for chemistry and ~6.9 mg isoprene m-2 h-1 taking detrainment into account. This surface flux is in general agreement with previous tropical forest studies. Inferred methanol and acetone emission fluxes are 0.5 mg methanol m¿2 h¿1 and 0.35 mg acetone m-2 h-1, respectively. The BVOC measurements were compared with fluxes and mixing ratios simulated with a single-column chemistry and climate model (SCM). The inferred isoprene flux is substantially smaller than that simulated with an implementation of a commonly applied BVOC emission algorithm in the SCM

VOC and ozone fluxes from a pine forest in the north of Belgium

Plants release large amounts of carbon as Volatile Organic Compounds (VOCs) into the atmosphere. These VOCs play an important role in the chemistry of the troposphere as they can be involved in the mechanisms of ozone and aerosol formation. The key mechanisms underneath biogenic VOC emissions are still not well understood, leading to large uncertainties in BVOC inventories on global and regional scales. Measurements of VOCs, ozone and micro-meteorology are conducted at the ‘De inslag’, a 80-year old mixed pine–oak forest located in the Campine region near Antwerp, Belgium. The forest site is a level-II plot of the European Programme of Intensive Monitoring Forest Ecosystems and is part of the Carboeuro and Nitroeurope-flux research network. The site is equipped with a flux tower that reaches above the 23m canopy. A Proton Transfer Reaction Mass Spectrometer and a Fast Ozone analyser allow determining VOC and ozone fluxes by Eddy Covariance. An analytic footprint model is used to exclude non-forest fluxes. In this study, we will test the accuracy of this footprint model with anthropogenic tracers (benzene and toluene)

Tapentadol Prolonged Release for Long-Term Treatment of Pain in Children

Purpose: Investigation of the efficacy and safety of tapentadol prolonged release (PR) compared with morphine PR for long-term treatment of pain in children. / Patients and Methods: Children aged 6 to < 18 years requiring long-term treatment with opioids were studied in a 12-month, 2-part, multi-center trial: Part 1, 14-day open-label, randomized, active-controlled, parallel group non-inferiority trial comparing twice daily tapentadol PR with morphine PR; Part 2, open-label treatment with tapentadol PR for up to 12 months or no treatment “safety observation period”. Pain intensity was rated with visual analogue scale or Faces Pain Scale-Revised, and non-inferiority was assessed by comparison of “treatment responders” (those completing the 14-day treatment period and showing pre-defined changes in pain rating) in each group. / Results: Twenty-three of 48 centers enrolled 73 patients. In Part 1, 45 and 24 patients received tapentadol or morphine, respectively, of which 40 and 22 completed 14-day treatment. In Part 2, thirty-six and 58 patients entered the tapentadol PR or observation periods, respectively, with 20/36 completing at least 12 weeks of treatment; 10 of the 36 had received morphine in Part 1. Forty-four of the 58 patients in the safety observation period had received tapentadol. Tapentadol PR was non-inferior to morphine PR (lower limit of confidence interval above negative non-inferiority margin of − 0.2) in Part 1. Rates of adverse events were as expected with nausea (22.2%) and constipation (15.6%) in the tapentadol PR group, and with vomiting (33.3%), nausea and constipation (each 16.7%) in the morphine PR group. No new safety issues were identified; the safety profile of tapentadol over the 12 months treatment and observation periods was comparable to that established in subjects > 18 years old. / Conclusion: Tapentadol PR was well tolerated and equivalent to morphine PR for both efficacy and safety in children (6 to < 18 years old) requiring long-term treatment with opioids

Automatic equine activity detection by convolutional neural networks using accelerometer data

In recent years, with a widespread of sensors embedded in all kind of mobile devices, human activity analysis is occurring more often in several domains like healthcare monitoring and fitness tracking. This trend did also enter the equestrian world because monitoring behaviours can yield important information about the health and welfare of horses. In this research, a deep learning-based approach for activity detection of equines is proposed to classify seven activities based on accelerometer data. We propose using Convolutional Neural Networks (CNN) by which features are extracted automatically by using strong computing capabilities. Furthermore, we investigate the impact of the sampling frequency, the time series length and the type of underground on which the data is gathered on the recognition accuracy and evaluate the model on three types of experimental datasets that are compiled of labelled accelerometer data gathered from six different subjects performing seven different activities. Afterwards, a horse-wise cross validation is carried out to investigate the impact of the subjects themselves on the model recognition accuracy. Finally, a slightly adjusted model is validated on different amounts of 50 Hz sensor data. A 99% accuracy can be reached for detecting seven behaviours of a seen horse when the sampling rate is 25 Hz and the time interval is 2.1 s. Four behaviours of an unseen horse can be detected with the same accuracy when the sampling rate is 69 Hz and the time interval is 2.4 s. Moreover, the accuracy of the model for the three datasets decreased on average with about 4.75% when the sampling rate was decreased from 200 Hz to 25 Hz and with 5.27% when the time interval was decreased from 3 s to 0.6 s. In addition, the classification performance of the activity "walk" was not influenced by the type of underground the horse was performing this movement on and even the model could conclude from which underground the data was gathered for three out of four undergrounds with accuracies above 93% at time intervals higher than 1.2 s. This ensures the evaluation of activity patterns in real world circumstances. The performance and ability of the model to generalise is validated on 50 Hz data from different horse types, using ten-fold cross validation, reaching a mean classification accuracy of 97.84% and 96.10% when validated on a lame horse and pony, respectively. Moreover, in this work we show that using data from one sensors is at the cost of only 0.24% reduction in accuracy (99.42% vs 99.66%)

Feasibility of wireless horse monitoring using a kinetic energy harvester model

To detect behavioral anomalies (disease/injuries), 24 h monitoring of horses each day is increasingly important. To this end, recent advances in machine learning have used accelerometer data to improve the efficiency of practice sessions and for early detection of health problems. However, current devices are limited in operational lifetime due to the need to manually replace batteries. To remedy this, we investigated the possibilities to power the wireless radio with a vibrational piezoelectric energy harvester at the leg (or in the hoof) of the horse, allowing perpetual monitoring devices. This paper reports the average power that can be delivered to the node by energy harvesting for four different natural gaits of the horse: stand, walking, trot and canter, based on an existing model for a velocity-damped resonant generator (VDRG). To this end, 33 accelerometer datasets were collected over 4.5 h from six horses during different activities. Based on these measurements, a vibrational energy harvester model was calculated that can provide up to 64.04 mu W during the energetic canter gait, taking an energy conversion rate of 60% into account. Most energy is provided during canter in the forward direction of the horse. The downwards direction is less suitable for power harvesting. Additionally, different wireless technologies are considered to realize perpetual wireless data sensing. During horse training sessions, BLE allows continues data transmissions (one packet every 0.04 s during canter), whereas IEEE 802.15.4 and UWB technologies are better suited for continuous horse monitoring during less energetic states due to their lower sleep current

Global atmospheric budget of acetaldehyde: 3-D model analysis and constraints from in-situ and satellite observations

We construct a global atmospheric budget for acetaldehyde using a 3-D model of atmospheric chemistry (GEOS-Chem), and use an ensemble of observations to evaluate present understanding of its sources and sinks. Hydrocarbon oxidation provides the largest acetaldehyde source in the model (128 Tg a&lt;sup&gt;&amp;minus;1&lt;/sup&gt;, a factor of 4 greater than the previous estimate), with alkanes, alkenes, and ethanol the main precursors. There is also a minor source from isoprene oxidation. We use an updated chemical mechanism for GEOS-Chem, and photochemical acetaldehyde yields are consistent with the Master Chemical Mechanism. We present a new approach to quantifying the acetaldehyde air-sea flux based on the global distribution of light absorption due to colored dissolved organic matter (CDOM) derived from satellite ocean color observations. The resulting net ocean emission is 57 Tg a&lt;sup&gt;&amp;minus;1&lt;/sup&gt;, the second largest global source of acetaldehyde. A key uncertainty is the acetaldehyde turnover time in the ocean mixed layer, with quantitative model evaluation over the ocean complicated by known measurement artifacts in clean air. Simulated concentrations in surface air over the ocean generally agree well with aircraft measurements, though the model tends to overestimate the vertical gradient. PAN:NO&lt;sub&gt;x&lt;/sub&gt; ratios are well-simulated in the marine boundary layer, providing some support for the modeled ocean source. We introduce the Model of Emissions of Gases and Aerosols from Nature (MEGANv2.1) for acetaldehyde and ethanol and use it to quantify their net flux from living terrestrial plants. Including emissions from decaying plants the total direct acetaldehyde source from the land biosphere is 23 Tg a&lt;sup&gt;&amp;minus;1&lt;/sup&gt;. Other terrestrial acetaldehyde sources include biomass burning (3 Tg a&lt;sup&gt;&amp;minus;1&lt;/sup&gt;) and anthropogenic emissions (2 Tg a&lt;sup&gt;&amp;minus;1&lt;/sup&gt;). Simulated concentrations in the continental boundary layer are generally unbiased and capture the spatial gradients seen in observations over North America, Europe, and tropical South America. However, the model underestimates acetaldehyde levels in urban outflow, suggesting a missing source in polluted air. Ubiquitous high measured concentrations in the free troposphere are not captured by the model, and based on present understanding are not consistent with concurrent measurements of PAN and NO&lt;sub&gt;x&lt;/sub&gt;: we find no compelling evidence for a widespread missing acetaldehyde source in the free troposphere. We estimate the current US source of ethanol and acetaldehyde (primary + secondary) at 1.3 Tg a&lt;sup&gt;&amp;minus;1&lt;/sup&gt; and 7.8 Tg a&lt;sup&gt;&amp;minus;1&lt;/sup&gt;, approximately 60{%} and 480% of the corresponding increases expected for a national transition from gasoline to ethanol fuel

Case Report:Bosentan and Sildenafil Exposure in Human Milk - A Contribution From the ConcePTION Project

Introduction: Quantitative information on disposition of maternal medicines in human milk remains a major knowledge gap. This case report presents the clinical and pharmacokinetic data of a single mother-infant pair exposed to bosentan and sildenafil for the treatment of pulmonary arterial hypertension (PAH) during lactation. Case presentation: A 43-year old mother was treated with sildenafil (20 mg, 3x/day) and bosentan (125 mg, 2x/day) for PAH. Her 21-months old infant received breastfeeding in combination with adequate complementary foods. Milk samples were collected over 24 h, at day 637 and 651 after delivery. The observed average steady-state concentrations of sildenafil (2.84 μg/L) and bosentan (49.0 μg/L) in human milk were low. The Daily Infant Dosage ingested by the nursing infant through human milk was 0.02 μg/kg/day for sildenafil and 0.29 μg/kg/day for bosentan at day 637, and 0.03 μg/kg/day and 0.60 μg/kg/day at day 651. The Relative Infant Dose calculated for an exclusively breastfed infant with an estimated milk intake of 150 ml/kg/day, was 0.06% for sildenafil and 0.24% for bosentan. General health outcome of the infant, reported by the mother, was uneventful until the sampling days. Conclusion: Low medicine concentrations were found in human milk expressed 21 months after delivery after maternal intake of 20 mg sildenafil three times daily and 125 mg bosentan twice daily. General health of the nursing infant until sampling was reported as optimal by the mother

Chemistry, transport and dry deposition of trace gases in the boundary layer over the tropical Atlantic Ocean and the Guyanas during the GABRIEL field campaign

We present a comparison of different Lagrangian and chemical box model calculations with measurement data obtained during the GABRIEL campaign over the tropical Atlantic Ocean and the Amazon rainforest in the Guyanas, October 2005. Lagrangian modelling of boundary layer (BL) air constrained by measurements is used to derive a horizontal gradient (&amp;asymp;5.6 pmol/mol km&lt;sup&gt;&amp;minus;1&lt;/sup&gt;) of CO from the ocean to the rainforest (east to west). This is significantly smaller than that derived from the measurements (16&amp;ndash;48 pmol/mol km&lt;sup&gt;&amp;minus;1&lt;/sup&gt;), indicating that photochemical production from organic precursors alone cannot explain the observed strong gradient. It appears that HCHO is overestimated by the Lagrangian and chemical box models, which include dry deposition but not exchange with the free troposphere (FT). The relatively short lifetime of HCHO implies substantial BL-FT exchange. The mixing-in of FT air affected by African and South American biomass burning at an estimated rate of 0.12 h&lt;sup&gt;&amp;minus;1&lt;/sup&gt; increases the CO and decreases the HCHO mixing ratios, improving agreement with measurements. A mean deposition velocity of 1.35 cm/s for H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; over the ocean as well as over the rainforest is deduced assuming BL-FT exchange adequate to the results for CO. The measured increase of the organic peroxides from the ocean to the rainforest (&amp;asymp;0.66 nmol/mol d&lt;sup&gt;&amp;minus;1&lt;/sup&gt;) is significantly overestimated by the Lagrangian model, even when using high values for the deposition velocity and the entrainment rate. Our results point at either heterogeneous loss of organic peroxides and/or their radical precursors, underestimated photodissociation or missing reaction paths of peroxy radicals not forming peroxides in isoprene chemistry. We calculate a mean integrated daytime net ozone production (NOP) in the BL of (0.2&amp;plusmn;5.9) nmol/mol (ocean) and (2.4&amp;plusmn;2.1) nmol/mol (rainforest). The NOP strongly correlates with NO and has a positive tendency in the boundary layer over the rainforest

Hydroxyl radicals in the tropical troposphere over the Suriname rainforest: airborne measurements

Direct measurements of OH and HO&lt;sub&gt;2&lt;/sub&gt; over a tropical rainforest were made for the first time during the GABRIEL campaign in October 2005, deploying the custom-built HORUS instrument (HydrOxyl Radical measurement Unit based on fluorescence Spectroscopy), adapted to fly in a Learjet wingpod. Biogenic hydrocarbon emissions were expected to strongly reduce the OH and HO&lt;sub&gt;2&lt;/sub&gt; mixing ratios as the air is transported from the ocean over the forest. However, surprisingly high mixing ratios of both OH and HO&lt;sub&gt;2&lt;/sub&gt; were encountered in the boundary layer over the rainforest. &lt;br&gt;&lt;br&gt; The HORUS instrumentation and calibration methods are described in detail and the measurement results obtained are discussed. The extensive dataset collected during GABRIEL, including measurements of many other trace gases and photolysis frequencies, has been used to quantify the main sources and sinks of OH. Comparison of these measurement-derived formation and loss rates of OH indicates strong previously overlooked recycling of OH in the boundary layer over the tropical rainforest, occurring in chorus with isoprene emission