Use of 137 Cs isotopic technique in soil erosion studies in Central Greece

The 137Cs technique was used to study soil erosion and deposition rates in soils in the Viotia prefecture, central Greece. Three sites with different soil types were selected and studied. Soils were sampled along transects and analyzed for 137Cs. The main goal of this field investigation was to study the 137Cs 3-D distribution pattern within key sites and to apply this information for the assessment of soil redistribution. The erosion and deposition rates were estimated using the proportional and the simplified mass balance models (Walling and He, 1997). Erosion and deposition rates predicted through the spatial distribution of 137Cs depended on the location of the profile studied in the landscape and were determined by the soil plough depth, the soil structure (bulk density), and the calibration model used to conve rt soil 137Cs measurements to estimates of soil redistribution rates. Estimated erosion rates for the Mouriki area site, varied from 16.62 to 102.56 t ha-1 y-1 for the top of the slope soil profile and from 5.37 to 25.68 t ha-1 y-1 for the middle of the slope soil profile. The deposition rates varied from 7.26 to 42.95 t ha-1 y-1 for the bottom of the slope soil profile

DDC (dopa decarboxylase (aromatic L-amino acid decarboxylase))

Review on DDC (dopa decarboxylase (aromatic L-amino acid decarboxylase)), with data on DNA, on the protein encoded, and where the gene is implicated

Use of 137 Cs isotopic technique in soil erosion studies in Central Greece

The 137Cs technique was used to study soil erosion and deposition rates in soils in the Viotia prefecture, central Greece. Three sites with different soil types were selected and studied. Soils were sampled along transects and analyzed for 137Cs. The main goal of this field investigation was to study the 137Cs 3-D distribution pattern within key sites and to apply this information for the assessment of soil redistribution. The erosion and deposition rates were estimated using the proportional and the simplified mass balance models (Walling and He, 1997). Erosion and deposition rates predicted through the spatial distribution of 137Cs depended on the location of the profile studied in the landscape and were determined by the soil plough depth, the soil structure (bulk density), and the calibration model used to conve rt soil 137Cs measurements to estimates of soil redistribution rates. Estimated erosion rates for the Mouriki area site, varied from 16.62 to 102.56 t ha-1 y-1 for the top of the slope soil profile and from 5.37 to 25.68 t ha-1 y-1 for the middle of the slope soil profile. The deposition rates varied from 7.26 to 42.95 t ha-1 y-1 for the bottom of the slope soil profile

The oxidizing power of the dark side: Rapid nocturnal aging of biomass burning as an overlooked source of oxidized organic aerosol

Oxidized organic aerosol (OOA) is a major component of ambient particulate matter, substantially affecting both climate and human health. A considerable body of evidence has established that OOA is readily produced in the presence of daylight, thus leading to the association of high concentrations of OOA in the summer or mid-afternoon. However, this current mechanistic understanding fails to explain elevated OOA concentrations during night or wintertime periods of low photochemical activity, thus leading atmospheric models to under predict OOA concentrations by a factor of 3-5. Here we show that fresh emissions from biomass burning rapidly forms OOA in the laboratory over a few hours and without any sunlight. The resulting OOA chemical composition is consistent with the observed OOA in field studies in major urban areas. To estimate the contribution of nocturnally aged OOA in the ambient atmosphere, we incorporate this nighttime-aging mechanism into a chemical-transport model and find that over much of the United States greater than 75% of the OOA formed from fresh biomass burning emissions underwent nighttime aging processes. Thus, the conceptual framework that OOA is predominantly formed in the presence of daylight fails to account for a substantial and rapid oxidation process occurring in the dark

Effect of the dietary inclusion of the growth promoter avoparcin on the performance and carcass characteristics of growing goat kids

Μελετήθηκε η επίδραση της αβοπαρκίνης ως αυξητικού παράγοντα στην πάχυνση των απογαλακτισμένων εριφίων, ηλικίας 8,5 μέχρι 20,5 εβδομάδων. Χρησιμοποιήθηκαν 32 εγχώρια ερίφια του τΰπου Capra prisca, που διαχωρίστηκαν σε δυο ομάδες (ομάδα μαρτύρων και ομάδα αβοπαρκίνης με αρχικό μέσο σωματικό βάρος 11,61 ± 1,16 kg και 11,57 ± 1,47 kg, αντίστοιχα) των 16 ζώων (8 αρσενικά και 8 θηλυκά) η καθεμιά. Όλα τα ερίφια διατράφηκαν βασικά με το ίδιο σιτηρέσιο, το οποίο αποτελούνταν από σανό μηδικής (μέση ημερήσια κατανάλωση 170 g/ερίφιο) και μίγμα συμπυκνωμένων ζωοτροφών (χορηγούμενο κατά βούληση). Τα ερίφια της ομάδας της αβοπαρκίνης έπαιρναν επιπλέον με την τροφή τους 20 mg αβοπαρκίνης/kg μίγματος συμπυκνωμένων ζωοτροφών. Η πρόσληψη αβοπαρκίνης από τα ερίφια βελτίωσε σημαντικά (Ρ<0,05) το σωματικό βάρος (ΣΒ) των εριφίων της ομάδας της αβοπαρκίνης έναντι εκείνου της ομάδας των μαρτύρων κατά 10,57% (19,24 ± 2,33 kg και 17,40 ± 2,30 kg, αντίστοιχα), την αύξηση σωματικού βάρους κατά 32,30% (7,66 ± 1,42 kg και 5,79 ± 1,74 kg, αντίστοιχα), τη μέση ημερήσια κατανάλωση της τροφής, σε ξηρή ουσία (ΞΟ), κατά 14,24% (551,80 ± 31,60 g ΞΟ και 483,02 ± 28,94 g ΞΟ, αντίστοιχα), το δείκτη μετατρεψιμότητας τροφής των εριφίων κατά 13,62% (6,09 ± 0,47 kg ΞΟ τροφής/kg αύξησης ΣΒ και 7,05 ± 0,56 kg ΞΟ τροφής/kg αύξησης ΣΒ, αντίστοιχα) και το βάρος σφαγίου κατά 14,86% (11,44 ± 1,48 kg και 9,96 ± 1,76 kg, αντίστοιχα). Δεν επηρέασε όμως σημαντικά (Ρ > 0,05) την απόδοση των εριφίων σε σφάγιο και τη χημική σύσταση του οΰτε τις κατά βάρος εκατοστιαίες αναλογίες του λεπτού εντέρου, του μείζονος επίπλου, των πνευμόνων, της καρδιάς, του ήπατος και του σπλήνα στο σωματικό βάρος.A trial was conducted with 32 indigenous goat kids (Capra prisca) 8,5 weeks old to examine the effectiveness of dietary avoparcin as growth promoting factor. The kids were randomly allocated into two groups (control- and avoparcin group with initial mean body weight of 11,61 ±1,16 kg and 11,57±1,47 kg, respectively) comprising of 16 kids (8 male and 8 female) each. For a period of 12 weeks, kids in the control group were given lucerne (alfalfa) hay (mean daily consumption 170 g/head) and an appropriate compound diet (given ad libitum), while kids in the avoparcin group were fed the same diet except that the compound diet was supplemented with avoparcin (20 mg/kg). Avoparcin supplementation significantly (P<0.05) improved final mean body weight by 10.57% (19.24 ± 2.33 kg vs. 17.40 ± 2.30 kg), body weight gain (BWG) by 32.30% (7.66 ± 1.42 kg vs. 5.79 ± 1.74 kg), mean daily feed consumption in dry matter basis (DM) by 14.24% (551.80 ± 31.60 g DM vs. 483.02 ± 28.94 g DM), feed conversion ratio by 13.62% (6.09 ± 0.47 kg DM consumption/kg BWG vs. 7.05 ± 0.56 kg DM consumption/kg BWG) and carcass weight by 14.86% (11.44 ± 1.48 kg vs. 9.96 ± 1.76 kg). Moreover, no significant differences (P>0.05) were noticed neither in carcass yield and carcass chemical composition nor in percentages of small intestine-, major omentum-, lung-,heart-, liver- and spleen weight in the body weight

Sensitivity of predicted ultrafine particle size distributions in Europe to different nucleation rate parameterizations using PMCAMx-UF v2.2

The three-dimensional chemical transport model, PMCAMx-UF v2.2, designed to simulate the ultrafine particle size distribution, was used to investigate the impact of varying nucleation mechanisms on the predicted aerosol number concentration in Europe. Two basic case scenarios were examined: the original ternary H2SO4–NH3–H2O parameterization and a biogenic vapor–sulfuric acid parameterization. Using the organic-based parameterization, PMCAMx-UF predicted higher N10 (particle number above 10 nm) concentrations over Europe by 40 %–60 % on average during the simulated period, which is a relatively small difference, given the differences in the two assumed mechanisms. The low sensitivity of the particle number concentrations to the nucleation mechanisms used in this study may not exist in other regions outside Europe. Adjusting the nucleation rate by an order of magnitude for both mechanisms led to an average change of ±30 % in N10 for the ternary ammonia case and −30 % to 40 % for the biogenic vapor case. In the biogenic organic nucleation scenario, reducing the fresh nuclei diameter from 1.7 to 1 nm resulted in reductions in N10 and N100 by −13 % and −1 %, respectively. Incorporating extremely low-volatility organic compounds (ELVOCs) as the nucleating species resulted in a predicted increase in the N10 concentration by 10 %–40 % over continental Europe compared to the ammonia parameterization. Model predictions were evaluated against field measurements from 26 stations across Europe during the summer of 2012. For N10, the ternary ammonia and ELVOC-based parameterizations were in better agreement with the field data compared to the other tested mechanisms. In the case of N100, all used parameterizations resulted in predictions that were consistent with the available field measurements.</p

Rapid dark aging of biomass burning as an overlooked source of oxidized organic aerosol

To quantify the full implications of biomass burning emissions on the atmosphere, it is essential to accurately represent the emission plume after it has undergone chemical aging in the atmosphere. Atmospheric models typically consider the predominant aging pathway of biomass burning emissions to take place in the presence of sunlight (via the OH radical); however, this mechanism leads to consistent underpredictions of oxidized organic aerosol in wintertime urban areas. Here, we show, through a combination of laboratory experiments, ambient field measurements, and chemical transport modeling, that biomass burning emission plumes exposed to NO2 and O3 age rapidly without requiring any sunlight, thus providing an overlooked source of oxidized organic aerosol previously not accounted for in models

Sources of water-soluble Brown Carbon at a South-Eastern European Site

Atmospheric brown carbon (BrC) is a highly uncertain, but potentially important contributor to light absorption in the atmosphere. Laboratory and field studies have shown that BrC can be produced from multiple sources, including primary emissions from fossil fuel combustion and biomass burning (BB), as well as secondary formation through a number of reaction pathways. It is currently thought that the dominant source of atmospheric BrC is primary emissions from BB, but relatively few studies demonstrate this in environments with complex source profiles. A field campaign was conducted during a month-long wintertime period in 2020 on the campus of the University of Peloponnese in the southwest of Patras, Greece which represents an urban site. During this time, ambient filter samples (a total of 35 filters) were collected from which the water-soluble BrC was determined using a semi-automated system similar to Hecobian et al. (2010), where absorption was measured over a 1 m path length. To measure the BrC, a UV-Vis Spectrophotometer was coupled to a Liquid Waveguide Capillary Cell and the light absorption intensity was recorded at 365 and 700 nm. The latter was used as a reference wavelength. We found that the average BrC absorption in Patras at a wavelength of 365 nm was 8.5 ± 3.9 Mm-1 suggesting that there was significant BrC in the organic aerosol during this period. Attribution of sources of BrC was done using simultaneous chemical composition data observations (primarily organic carbon, black carbon, and nitrate) combined with Positive Matrix Factorization analysis. This analysis showed that in addition to the important role of biomass burning (a contribution of about 20%) and other combustion emissions (also close to 20%), oxidized organic aerosol (approximately 40%) is also a significant contributor to BrC in the study area. Reference Hecobian, A., Zhang, X., Zheng, M., Frank, N., Edgerton, E.S., Weber, R.J., 2010. Water-soluble organic aerosol material and the light-absorption characteristics of aqueous extracts measured over the Southeastern United States. Atmos. Chem. Phys. 10, 5965–5977. https://doi.org/10.5194/acp-10-5965-201

Oxidative Potential of Atmospheric Particles at an Eastern Mediterranean Site

Aerosol oxidative potential (OP; the inherent ability of ambient particles to generate reactive oxygen species in vivo) may be linked to the health effects of population exposure to aerosol and is a metric of their toxicity. The goal of this work was to quantify the water-soluble OP of particles in an urban area in Patras, Greece and to investigate its links with source emissions or components of this particulate matter (PM). A field campaign was conducted during a monthlong wintertime period in 2020 (January 10 to February 13) on the campus of the University of Peloponnese in the southwest of Patras. During this time, ambient filter samples (a total of 35 filters) were collected. To measure the water-soluble OP we used a semiautomated system similar to Fang et al. (2015) based on the dithiothreitol (DTT) assay. The accuracy of our system was validated by measuring the DTT activity of 11 phenanthrequinone (PQN) solutions on both our system and the identical semi-automated validated system at the National Observatory of Athens (NOA). These two sets of analysed DTT activities (current vs. NOA system) were significantly correlated (R2=0.99) with a slope of 1.15 ± 0.04 and an intercept close to zero. We found that the average water-soluble OP in Patras was 1.5 ± 0.3 nmol min-1 m-3, ranging from 0.7 to 2 nmol min-1 m-3. The OP measured in Patras during the campaign is higher than reported values from similar wintertime studies in other urban areas such as Athens (Paraskevopoulou et al., 2019). The average watersoluble OP during a summer study for Patras was significantly lower and equal to 0.18 ± 0.02 nmol min-1 m- 3. Taking into account the average PM1 mass concentrations for these two periods (summer: 6 μg m-3 and winter: 23 μg m-3) it is clear that the increase in OP was two times the increase in PM mass making the wintertime aerosol more toxic. Additionally, the water-soluble brown carbon (BrC) was determined using an offline semi-automated system, where absorption was measured over a 1 m path length. The average BrC absorption in Patras at a wavelength of 365 nm was 8.6 ± 3.9 Mm-1 suggesting that there was significant BrC in the organic aerosol during this period. The coefficients of determination, R2, in Table 1 are used as a metric of the potential relationships between the various carbonaceous aerosol components and the DTT activity. The results suggest that the OP is not dominated by a single source or component, but that there are multiple components contributing to it during the study period. Interestingly, the highest correlation coefficient (R2 = 0.46) was found between the OP and Brown Carbon. This is consistent with recently published results for an urban site in Atlanta where the oxidative potential measured with the DTT method also had stronger correlations with BrC during the winter (Gao et al., 2020)

Chemical evolution of primary and secondary biomass burning aerosols during daytime and nighttime

Primary emissions from wood and pellet stoves were aged in an atmospheric simulation chamber under daytime and nighttime conditions. The aerosol was analyzed with the online Aerosol Mass Spectrometer (AMS) and offline Fourier transform infrared spectroscopy (FTIR). Measurements using the two techniques agreed reasonably well in terms of the organic aerosol (OA) mass concentration, OA:OC trends, and concentrations of biomass burning markers – lignin-like compounds and anhydrosugars. Based on the AMS, around 15 % of the primary organic aerosol (POA) mass underwent some form of transformation during daytime oxidation conditions after 6–10 hours of atmospheric exposure. A lesser extent of transformation was observed during the nighttime oxidation. The decay of certain semi-volatile (e.g., levoglucosan) and less volatile (e.g., lignin-like) POA components was substantial during aging, highlighting the role of heterogeneous reactions and gas-particle partitioning. Lignin-like compounds were observed to degrade under both daytime and nighttime conditions, whereas anhydrosugars degraded only under daytime conditions. Among the marker mass fragments of primary biomass burning OA (bbPOA), heavy ones (higher m/z) were relatively more stable during aging. The biomass burning secondary OA (bbSOA) became more oxidized with continued aging and resembled those of aged atmospheric organic aerosols. The bbSOA formed during daytime oxidation was dominated by acids. Organonitrates were an important product of nighttime reactions in both humid and dry conditions. Our results underline the importance of changes to both the primary and secondary biomass burning aerosols during their atmospheric aging. Heavier AMS fragments seldomly used in atmospheric chemistry can be used as more stable tracers of bbPOA and in combination with the established levoglucosan marker, can provide an indication of the extent of bbPOA aging