Propagation of gravity waves and spread F in the low-latitude ionosphere over Tucumán, Argentina, by continuous Doppler sounding: first results

Results of systematic analysis of propagation directions and horizontal velocities of gravity waves (GWs) and spread F structures in low-latitude ionosphere (magnetic inclination ~27°) in Tucumán region, Argentina, are presented. Measurements were carried out by multipoint continuous Doppler system during 1 year from December 2012 to November 2013. It was found that meridian propagation of GWs dominated and that southward propagation prevailed in the local summer. Oblique spread structures observed in Doppler shift spectrograms and associated with spread F propagated roughly eastward at velocities from ~70 to ~180 m/s and were observed at night from ~ September to ~ March. The velocities were computed for 182 events and the azimuths for 64 events. Continuous Doppler sounding makes it possible to analyze more events compared to optical observations often used for propagation studies since the measurements do not depend on weather.Fil: Chum, J.. Institute of Atmospheric Physics; República ChecaFil: Miranda Bonomi, Fernando Alberto. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Electricidad, Electrónica y Computación. Laboratorio de Telecomunicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fišer, J.. Institute of Atmospheric Physics; República ChecaFil: Cabrera, M. A.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Electricidad, Electrónica y Computación. Laboratorio de Telecomunicaciones; Argentina. Universidad Tecnológica Nacional. Facultad Regional Tucuman; ArgentinaFil: Ezquer, Rodolfo Gerardo. Universidad Tecnológica Nacional. Facultad Regional Tucuman; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionosfera; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Burešová, D.. Institute of Atmospheric Physics; República ChecaFil: Laštovička, J.. Institute of Atmospheric Physics; República ChecaFil: Baše, J.. Institute of Atmospheric Physics; República ChecaFil: Hruška, F.. Institute of Atmospheric Physics; República ChecaFil: Molina, Maria Graciela. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Ciencias de la Computación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ise, Juan Eduardo. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Electricidad, Electrónica y Computación. Laboratorio de Telecomunicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cangemi, José Ignacio. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Electricidad, Electrónica y Computación. Laboratorio de Telecomunicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Šindelářová, T.. Institute of Atmospheric Physics; República Chec

Positron annihilation spectroscopy study of radiation-induced defects in W and Fe irradiated with neutrons with different spectra

The paper presents new knowledge on primary defect formation in tungsten (W) and iron (Fe) irradiated by fission and high-energy neutrons at near-room temperature. Using a well-established method of positron-annihilation lifetime-spectroscopy (PALS), it was found that irradiation of W in the fission reactor and by high-energy neutrons from the p(35 MeV)-Be generator leads to the formation of small radiation-induced vacancy clusters with comparable mean size. In the case of Fe, smaller mean size of primary radiation-induced vacancy clusters was measured after irradiation with fission neutrons compared to irradiation with high-energy neutrons from the p(35 MeV)-Be generator. It was found that one of the reasons of the formation of the larger size of the defects with lower density in Fe is lower flux in the case of irradiation with high-energy neutrons from the p(35 MeV)-Be source. The second reason is enhanced defect agglomeration and recombination within the energetic displacement cascade at high energy primary knock-on-atoms (PKAs). This is consistent with the concept of the athermal recombination corrected (arc-dpa) model, although the measured dpa cross-section of both fission neutrons and wide-spectrum high-energy neutrons in W is between the conventional Norgett–Robinson–Torrens (NRT-dpa) and arc-dpa predictions. This means that the physics of the primary radiation effects in materials is still not fully known and requires further study through a combination of modeling and experimental efforts. The present data serve as a basis for the development of an improved concept of the displacement process

Changes in soil dissolved organic carbon affect reconstructed history and projected future trends in surface water acidification

Preindustrial (1850s) and future (2060) streamwater chemistry of an anthropogenically acidified small catchment was estimated using the MAGIC model for three different scenarios for dissolved organic carbon (DOC) concentrations and sources. The highest modeled pH = 5.7 for 1850s as well as for 2060 (pH = 4.4) was simulated given the assumption that streamwater DOC concentration was constant at the 1993 level. A scenario accounting for an increase of DOC as an inverse function of ionic strength (IS) of soilwater and streamwater resulted in much lower preindustrial (pH = 4.9) and future recovery to (pH = 4.1) if the stream riparian zone was assumed to be the only DOC source. If upland soilwater (where significant DOC increase was observed at −5 and −15 cm) was also included, DOC was partly neutralized within the soil and higher preindustrial pH = 5.3 and future pH = 4.2 were estimated. The observed DOC stream flux was 2–4 times higher than the potential carbon production of the riparian zone, implying that this is unlikely to be the sole DOC source. Modeling based on the assumption that stream DOC changes are solely attributable to changes in the riparian zone appears likely to underestimate preindustrial pH

Contrasting vulnerability of drained tropical and high-latitude peatlands to fluvial loss of stored carbon

Carbon sequestration and storage in peatlands rely on consistently highwater tables. Anthropogenic pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of peat-forming vegetation and exposure of previously anaerobic peat to aerobic decomposition. This can shift peatlands from net CO2 sinks to large CO2 sources, releasing carbon held for millennia. Peatlands also export significant quantities of carbon via fluvial pathways, mainly as dissolved organic carbon (DOC). We analyzed radiocarbon (14C) levels of DOC in drainage water from multiple peatlands in Europe and Southeast Asia, to infer differences in the age of carbon lost from intact and drained systems. In most cases, drainage led to increased release of older carbon from the peat profile but withmarked differences related to peat type. Very low DOC-14C levels in runoff from drained tropical peatlands indicate loss of very old (centuries to millennia) stored peat carbon. High-latitude peatlands appear more resilient to drainage; 14C measurements from UK blanket bogs suggest that exported DOC remains young (500 year) carbon in high-latitude systems. Rewetting at least partially offsets drainage effects on DOC age

Assessing recovery from acidification of European surface waters in the year 2010: evaluation of projections made with the MAGIC model in 1995

In 1999 we used the MAGIC (Model of Acidification of Groundwater In Catchments) model to project acidification of acid-sensitive European surface waters in the year 2010, given implementation of the Gothenburg Protocol to the Convention on Long-Range Transboundary Air Pollution (LRTAP). A total of 202 sites in 10 regions in Europe were studied. These forecasts can now be compared with measurements for the year 2010, to give a “ground truth” evaluation of the model. The prerequisite for this test is that the actual sulfur and nitrogen deposition decreased from 1995 to 2010 by the same amount as that used to drive the model forecasts; this was largely the case for sulfur, but less so for nitrogen, and the simulated surface water [NO3–] reflected this difference. For most of the sites, predicted surface water recovery from acidification for the year 2010 is very close to the actual recovery observed from measured data, as recovery is predominantly driven by reductions in sulfur deposition. Overall these results show that MAGIC successfully predicts future water chemistry given known changes in acid deposition

Regional assessment of the current extent of acidification of surface waters in Europe and North America

The current status of surface water acidification related to air pollution in Europe and North America has been assessed using country reports, monitoring data, critical loads and exceedance data, acid sensitivity and deposition maps, and data reported under the European Commission’s Water Framework Directive (WFD). Acidification is still observed in many countries, but the extent and severity vary. Maps of acid sensitivity and deposition suggest that surface water acidification is present in regions and countries for which no data or reports were delivered for the current assessment. Existing national monitoring varies in the ability to assess the spatial extent of acidification and the recovery responses of acidified sites. The monitoring requirements under the European Union’s National Emission Ceilings Directive are expected to reverse the recent decline in the number of monitoring sites observed in some countries. The information reported under the WFD is currently of limited value in assessing the extent of acidification of surface waters in Europe. Chemical recovery in response to reductions in acid deposition can be slow, and biological recovery can lag severely behind. Despite large and effective efforts across Europe and North America to reduce surface water acidification, air pollution still constitutes a threat to freshwater ecosystems

Ontogeny of juvenile freshwater pearl mussels, Margaritifera margaritifera (Bivalvia: Margaritiferidae).

The gills of juvenile freshwater bivalves undergo a complex morphogenesis that may correlate with changes in feeding ecology, but ontogenic studies on juvenile mussels are rare. Scanning electron microscopy was used to examine the ultrastructure and ontogeny of 117 juvenile freshwater pearl mussels (Margaritifera margaritifera) ranging in age from 1–44 months and length from 0.49–8.90 mm. Three stages of gill development are described. In Stage 1 (5–9 inner demibranch filaments), only unreflected inner demibranch filaments were present. In Stage 2 (9–17 inner demibranch filaments), inner demibranch filaments began to reflect when shell length exceeded 1.13 mm, at 13–16 months old. Reflection began in medial filaments and then proceeded anterior and posterior. In Stage 3 (28–94 inner demibranch filaments), outer demibranch filaments began developing at shell length > 3.1 mm and about 34 months of age. The oral groove on the inner demibranch was first observed in 34 month old specimens > 2.66 mm but was never observed on the outer demibranch. Shell length (R2 = 0.99) was a better predictor of developmental stage compared to age (R2 = 0.84). The full suite of gill ciliation was present on filaments in all stages. Interfilamentary distance averaged 31.3 μm and did not change with age (4–44 months) or with size (0.75–8.9 mm). Distance between laterofrontal cirri couplets averaged 1.54 μm and did not change significantly with size or age. Labial palp primordia were present in even the youngest individuals but ciliature became more diverse in more developed individuals. Information presented here is valuable to captive rearing programmes as it provides insight in to when juveniles may be particularly vulnerable to stressors due to specific ontogenic changes. The data are compared with two other recent studies of Margaritifera development.N/

Predicting attitudinal and behavioral responses to COVID-19 pandemic using machine learning

At the beginning of 2020, COVID-19 became a global problem. Despite all the efforts to emphasize the relevance of preventive measures, not everyone adhered to them. Thus, learning more about the characteristics determining attitudinal and behavioral responses to the pandemic is crucial to improving future interventions. In this study, we applied machine learning on the multi-national data collected by the International Collaboration on the Social and Moral Psychology of COVID-19 (N = 51,404) to test the predictive efficacy of constructs from social, moral, cognitive, and personality psychology, as well as socio-demographic factors, in the attitudinal and behavioral responses to the pandemic. The results point to several valuable insights. Internalized moral identity provided the most consistent predictive contribution—individuals perceiving moral traits as central to their self-concept reported higher adherence to preventive measures. Similar was found for morality as cooperation, symbolized moral identity, self-control, open-mindedness, collective narcissism, while the inverse relationship was evident for the endorsement of conspiracy theories. However, we also found a non-negligible variability in the explained variance and predictive contributions with respect to macro-level factors such as the pandemic stage or cultural region. Overall, the results underscore the importance of morality-related and contextual factors in understanding adherence to public health recommendations during the pandemic