Exploring Magnetic Properties as a Potential Pollution Proxy for Monitoring Levels and Bioaccessibility of Lead (Pb) in Playground Sand: a Preliminary Study  

2021 ◽  
Author(s):  
Anna Bourliva ◽  
Elina Aidona ◽  
Carla Patinha
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Measurements ◽  
The European Union ◽  
Soil Dust ◽  
Case Scenario ◽  
Northern Greece ◽  
Development Education ◽  
Worst Case ◽  
Magnetic Phases ◽  
Social Fund

<p>The need to control soil/dust quality in recreation sites of urban agglomerations, especially in those where children are exposed, has been extensively highlighted. Particularly, in children’s play sites it is imperative to quantify the levels of potential harmful elements (PHEs) in soils and dusts. Particularly, lead (Pb) is an element of concern since exposure of children to Pb and the consequently elevated blood Pb levels are linked to severe behavioral disorders and reductions of intellectual function. On the other hand, the use of magnetic methods is proposed as a quick and inexpensive first step in assessing soil/dust pollution by providing qualitative data on its degree and extent. The aim of the present study was to perform magnetic measurements in order to find a relationship between levels and bioaccessibility of Pb in playground sands and sand-bound iron-bearing magnetic phases. For this reason, composite sand samples were collected within the top layer at 37 public playgrounds in the broader area of the city of Thessaloniki, Northern Greece. Sampling conducted from 2-5 spots of the playground not covered by the treetops, nor at the edge of the playground or near to vegetation or urban furniture. The mass specific magnetic susceptibility (χ<sub>lf</sub>) of the playground sands exhibited a range of 51-248.7 x 10<sup>-8</sup> m<sup>3</sup> kg<sup>-1</sup> with a median of 149.8 x10<sup>-8</sup> m<sup>3</sup> kg<sup>-1</sup> indicating a notable amount of sand-bound Fe-bearing magnetic phases. The frequency dependent magnetic susceptibility (χ<sub>fd</sub>) varied among 0.11 to 7.73% with only limited sand samples exhibiting values >5%, suggesting the lack of super paramagnetic magnetite grains within the majority of the studied samples. The total Pb concentrations in playground sands ranged from 18.6 to 46.7 mg kg<sup>-1</sup> with a median of  28.7 mg kg<sup>-1 </sup>and lies within the ranges reported by other researchers. Despite the insignificant differences observed on Pb contents among a sub-set of 12 sands with elevated χ<sub>lf</sub> values (mean Pb 31.3 mg kg<sup>-1</sup> , χ<sub>lf</sub> > 175 x 10<sup>-8</sup> m<sup>3</sup> kg<sup>-1</sup> ) and the rest of the samples (mean Pb 29.7 mg kg<sup>-1</sup>), a moderate correlation coefficient (r=0.685, p<0.05) was recorded between χ<sub>lf</sub> and Pb in the enhanced magnetized sub-set underscoring a probable linkage with the ferrimagnetic particles of playground sand. Bioaccessible Pb concentrations (gastric phase) ranged from 5.73 to 20.7 mg kg<sup>-1</sup> with 22-44% of Pb being in  bioaccessible form in the playground sands. Different lead intake scenarios (based on bioaccessible Pb) underscored no health risk for children through sand ingestion with the exception of a worst case scenario of pica behaviour (intake 20g/d).</p><p><strong>Acknowledgements:</strong> This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning» in the context of the project “Reinforcement of Postdoctoral Researchers - 2<sup>nd</sup> Cycle” (MIS-5033021), implemented by the State Scholarships Foundation (ΙΚΥ).</p>

Venezuela: Political Confrontation and the World Community

2020 ◽  
Vol 12 (2) ◽  
pp. 71-111
Author(s):  
Z. W. Iwanowski ◽  
D. M. Rozental
Keyword(s):  
Latin American ◽  
Hot Spot ◽  
The United States ◽  
World Politics ◽  
The European Union ◽  
Case Scenario ◽  
Worst Case ◽  
Systemic Crisis ◽  
The Government ◽  
External Forces

The paper examines a complex web of domestic and external issues which have both provoked a systemic crisis in Venezuela and, at the same time, determined its specificity in comparison with the wave of protests sweeping across Latin America in 2019.The authors conclude that the escalation of the conflict in Venezuela was caused not only by the standoff between the legislative and the executive branches of the government, but also by the split of the whole society into proponents and opponents of ‘socialism of the 21st century’. The contradictions have led to the formation of the parallel branches of power: two presidents, two parliaments and two supreme courts (one of them in exile) which de facto coexist in the country and each claims exclusive rights and legitimacy.The authors also stress that the situation in Venezuela has obvious regional consequences. The miscalculations of the incumbent president were used in election campaigns in other Latin American countries and became one of the reasons for the defeat of left candidates, the subsequent ‘right drift’ leading to the isolation of the republic. The new political landscape has also affected the architecture of integration associations, which failed to develop a unified position toward the Bolivarian regime.Furthermore, in a current heightened state of international tensions Venezuela has turned into a theatre of international rivalry and conflict involving all the key subjects of world politics. The United States, China, Russia and the European Union compete for the energy resources of the country and pursue their own strategic interests. The inability or unwillingness of external forces to reach compromise and to bring the parties to the negotiating table can pose a threat to peace and international security.As a result, Venezuela has become one of the most turbulent countries in the region. At the same time, the repeated outbursts of protest waves are significantly different from popular uprisings in other Latin American states. In the worst-case scenario, a constantly worsening situation may result in a social explosion which threatens to make the Bolivarian Republic another hot spot of the planet.

scholarly journals Generating unfavourable VaR scenarios under Solvency II with patchwork copulas

2021 ◽  
Vol 9 (1) ◽  
pp. 327-346
Author(s):  
Dietmar Pfeifer ◽  
Olena Ragulina
Keyword(s):  
Value At Risk ◽  
Insurance Industry ◽  
Solvency Ii ◽  
Two Dimensions ◽  
Insurance Companies ◽  
The European Union ◽  
Case Scenario ◽  
Worst Case ◽  
Risk Scenarios ◽  
Copula Approach

Abstract The central idea of the paper is to present a general simple patchwork construction principle for multivariate copulas that create unfavourable VaR (i.e. Value at Risk) scenarios while maintaining given marginal distributions. This is of particular interest for the construction of Internal Models in the insurance industry under Solvency II in the European Union. Besides this, the Delegated Regulation by the European Commission requires all insurance companies under supervision to consider different risk scenarios in their risk management system for the company’s own risk assessment. Since it is unreasonable to assume that the potential worst case scenario will materialize in the company, we think that a modelling of various unfavourable scenarios as described in this paper is likewise appropriate. Our explicit copula approach can be considered as a special case of ordinal sums, which in two dimensions even leads to the technically worst VaR scenario.

On the origin of Ultra-Low Frequency (ULF) waves in sudden and quasiperiodic solar wind dynamic pressure variations penetrating into Earth’s magnetosphere

2021 ◽  
Author(s):  
Marina Georgiou ◽  
Christos Katsavrias ◽  
Ioannis Daglis ◽  
Georgios Balasis ◽  
Alexander Hillaris
Keyword(s):  
Solar Wind ◽  
Wavelet Transform ◽  
Dynamic Pressure ◽  
Low Frequency ◽  
Velocity Shear ◽  
Solar Wind Dynamic Pressure ◽  
Slow Solar Wind ◽  
The European Union ◽  
Development Education ◽  
Social Fund

<p>Several observational studies have shown that external (i.e. solar wind and magnetosheath) dynamic pressure variations can drive quasi-periodic perturbations of the geomagnetic field. In this study, we utilise multi-spacecraft (ARTEMIS, Cluster, GOES, and THEMIS) mission measurements and investigate step-like increases and quasi-periodic variations of solar wind dynamic pressure as the source mechanism of geomagnetic pulsations with frequencies between ~0.5 to 15 mHz. During intervals of slow solar wind and low geomagnetic activity — to exclude waves generated by velocity shear at the magnetopause and substorm contributions — common periodicities in electromagnetic field oscillations inside the magnetosphere and the solar wind driver are detected in Lomb-Scargle periodograms. The causal relationship is examined in frequency and polarisation signatures of waves detected at the various probes using continuous wavelet transform, cross-wavelet spectra and wavelet transform coherence. The observed dependence of wave properties on their localisation offers excellent source verification for ULF Pc4-5  waves originating in dynamic pressure variations in the upstream solar wind and propagating in the dayside magnetosphere through the field line resonance process.</p><p>This research is co-financed by Greece and the European Union (European Social Fund - ESF) through the Operational Programme “Human Resources Development, Education and Lifelong Learning 2014-2020” in the context of the project ULFpulse (MIS: 5048130).</p>

Early Miocene mollusc and fish biodiversity at the Proto-Mediterranean–Paratethys marine corridor

2021 ◽  
Author(s):  
Efterpi Koskeridou ◽  
Konstantina Agiadi ◽  
Danae Thivaiou
Keyword(s):  
Middle Miocene ◽  
Fish Fauna ◽  
Early Miocene ◽  
Marine Biodiversity ◽  
The European Union ◽  
Development Education ◽  
Marine Fauna ◽  
European Social Fund ◽  
Social Fund ◽  
Fish Migrations

<p>Marine biodiversity is controlled by depth, climate, and ocean connectivity. The early Miocene marine fauna of the proto-Mediterranean is particularly important because this is the time when the connection with the Indo-Pacific realm was disrupted , and the marine biodiversity hotspot shifted toward the southeast, marking the onset of a subtropical gradually oligotrophic regime in the proto-Mediterranean Sea. The Mesohellenic basin in particular, at the northern part of the proto-Mediterranean, was located at the intersection with the Paratethys epicontinental sea. Therefore, the fauna in this area was influenced by the conditions in both basins. In this study, we present the mollusc and fish fauna of the Aquitanian Mesohellenic basin and discuss its paleobiogeographic and evolutionary implications. Comparisons and assessment of faunal similarities of the proto-Mediterranean and adjacent provinces is carried out using ordination methods to treat available data from relevant publications and the Paleobiology Database (PBDB).</p><p>This research has been co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme “Human Resources Development, Education and Lifelong Learning 2014–2020” in the context of the project “Mollusc and fish migrations in the dynamic environments of the early to middle Miocene in the Mediterranean” (MIS 5047960). </p>

scholarly journals Φυσικογεωγραφική, ιζηματολογική μελέτη και ανίχνευ-ση των μαγνητικών ιδιοτήτων των ιζημάτων του ‘Μικρού’ σπηλαίου των Επταμύλων Σερρών

2017 ◽  
Vol 44 ◽  
pp. 37
Author(s):  
Σ. Πεχλιβανίδου ◽  
E. Αηδονά ◽  
Κ. Βουβαλίδης ◽  
Χ. Πέννος ◽  
Κ. Αλμπανάκης
Keyword(s):  
Grain Size ◽  
Magnetic Susceptibility ◽  
Magnetic Measurements ◽  
Environmental Magnetism ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Sedimentary Sequence ◽  
Northern Greece ◽  
Depositional Processes ◽  
Clastic Sediments

In the area of Eptamili Village, located at the foothills of the southern-eastern part of Mount Menoikio (Serres Prefecture, Northern Greece) two underground karst cavities were revealed during the works of marble exploitation, named as ‘Mikro’ and ‘Megalo’ Cave of Eptamilon. At the entrance of the ‘Mikro’ Cave there is a naturally deposited sequence of clastic sediments alternating with chemical deposits with a thickness of ~2m, lying uncomfortably on the bedrock marbles. In order to investigate the depositional processes and conditions and to understand the palaeoenvironmental changes during the cave evolution, grain size analysis and magnetic measurements were conducted on sediment samples from the sedimentary sequence. Grain size analysis showed the presence of fine sandy beds alternating with silty and clayey layers. This structure correlates with the magnetic signature of the sediments and especially the magnetic susceptibility (xlf) and the frequency depended magnetic susceptibility (xfd), conducting conclusions concerning the palaeoclimatic conditions and the velocity of the flow during the time of deposition of the sedimentary sequence. This study suggest the use of environmental magnetism as an independent methodology in palaeoenvironmental studies.

scholarly journals Environmental magnetism: Application to cave sediments

2017 ◽  
Vol 47 (2) ◽  
pp. 892 ◽  
Author(s):  
E. Aidona ◽  
S. Pechlivanidou ◽  
Ch. Pennos
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Measurements ◽  
Low Cost ◽  
Environmental Magnetism ◽  
Northern Greece ◽  
Cave Sediments ◽  
Wide Range ◽  
Sediment Records ◽  
Archaeological Artifacts

Environmental magnetism techniques allow a rapid, low cost and sensitive characterization of sediments and can be applied in a wide range of environments. More specific, magnetic properties can be successfully used to reconstruct paleoenvironmental and paleoclimatic conditions in rockshelter and cave sites. Cave sediments, imprint the environmental conditions at the Earth’s surface at the time of deposition since are well protected both at the interior and at the entrance of the cave systems. In addition, many cultural sequences and archaeological artifacts are well preserved in rockshelter and cave sediment records and can be effectively used for paleoenvironmental interpretations. In this study we present data from two different cave sites from Northern Greece. In the first cave (Maronia Cave) magnetic measurements were performed in two cores 80 and 90 cm, respectively, located inside the cave area. High values of magnetic susceptibility are directly linked with the human activity inside the cave, while lower values show deposition under infiltration and fluvial processes. In the second cave (Mikro Eptamilon Cave), magnetic susceptibility and frequency dependent magnetic susceptibility depicted from a sedimentary sequence with a thickness of 200 cm, located in the entrance of the cave. Results lead to conclusions concerning the velocity of the paleo-flow likely related to the paleoclimatic conditions that dominated the broader area.

Effect of Egg Washing on the Cuticle Quality of Brown and White Table Eggs

2011 ◽  
Vol 74 (10) ◽  
pp. 1649-1654 ◽  
Author(s):  
S. LELEU ◽  
W. MESSENS ◽  
K. DE REU ◽  
S. DE PRETER ◽  
L. HERMAN ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Egg Laying ◽  
The European Union ◽  
Case Scenario ◽  
Worst Case ◽  
Consumer Safety ◽  
Washing Process ◽  
Scanning Electron

Egg washing is currently not permitted within the European Union, with few exceptions. This is mainly because there are concerns that cuticle damage could occur during or after the washing process, as a result of a suboptimal operation. In this study, the cuticle coverage levels of 400 washed or unwashed eggs, derived from either a brown or a white egg–laying flock at the end of lay, were compared. The eggs from older hens inherently have poorer cuticle coverage and as a result arguably constitute a greater risk to consumer safety if they are then washed. Thus, the effects of the washing procedure used in this study on cuticle quality were tested under the worst-case scenario. A standard Swedish egg washing process was used. The cuticle coverage of the eggs was assessed by a colorimeter by quantifying the color difference before and after staining with Tartrazine and Green S. The cuticle of an additional 30 eggs from each of the four groups was then visually assessed by scanning electron microscopy. The staining characteristics of the cuticle varied greatly within each group of eggs and showed that the washing process did not lead to cuticle damage. Scanning electron microscopy confirmed that there was no irreversible damage to the cuticle of the washed eggs and that it was not possible to correctly assign the treatment (washed or not) based on a visual assessment. In conclusion, no evidence could be found to suggest that the washing procedure used in this investigation irreversibly changed the quality of the cuticle.

Reducing Probabilistic Weather Forecasts to the Worst Case Scenario: Anchoring Effects

2008 ◽  
Author(s):  
Sonia Savelli ◽  
Susan Joslyn ◽  
Limor Nadav-Greenberg ◽  
Queena Chen
Keyword(s):  
Case Scenario ◽  
Worst Case ◽  
Weather Forecasts ◽  
Worst Case Scenario ◽  
Anchoring Effects

EXPEDITION TO MALI, 2020

2020 ◽  
pp. 12-28
Author(s):  
D. V. Vaniukova ◽  
◽  
P. A. Kutsenkov ◽  
Keyword(s):  
Mass Murder ◽  
The State ◽  
Case Scenario ◽  
Worst Case ◽  
Traditional Art ◽  
Peter The Great ◽  
State Museum ◽  
Bobo Dioulasso ◽  
Oriental Studies ◽  
The Village

The research expedition of the Institute of Oriental studies of the Russian Academy of Sciences has been working in Mali since 2015. Since 2017, it has been attended by employees of the State Museum of the East. The task of the expedition is to study the transformation of traditional Dogon culture in the context of globalization, as well as to collect ethnographic information (life, customs, features of the traditional social and political structure); to collect oral historical legends; to study the history, existence, and transformation of artistic tradition in the villages of the Dogon Country in modern conditions; collecting items of Ethnography and art to add to the collection of the African collection of the. Peter the Great Museum (Kunstkamera, Saint Petersburg) and the State Museum of Oriental Arts (Moscow). The plan of the expedition in January 2020 included additional items, namely, the study of the functioning of the antique market in Mali (the “path” of things from villages to cities, which is important for attributing works of traditional art). The geography of our research was significantly expanded to the regions of Sikasso and Koulikoro in Mali, as well as to the city of Bobo-Dioulasso and its surroundings in Burkina Faso, which is related to the study of migrations to the Bandiagara Highlands. In addition, the plan of the expedition included organization of a photo exhibition in the Museum of the village of Endé and some educational projects. Unfortunately, after the mass murder in March 2019 in the village of Ogossogou-Pel, where more than one hundred and seventy people were killed, events in the Dogon Country began to develop in the worst-case scenario: The incessant provocations after that revived the old feud between the Pel (Fulbe) pastoralists and the Dogon farmers. So far, this hostility and mutual distrust has not yet developed into a full-scale ethnic conflict, but, unfortunately, such a development now seems quite likely.

Risk-Based Robust Bidding Strategies for EVs’ Aggregators in Day-ahead Markets with Uncertainty

2020 ◽  
Author(s):  
Ahmed Abdelmoaty ◽  
Wessam Mesbah ◽  
Mohammad A. M. Abdel-Aal ◽  
Ali T. Alawami
Keyword(s):  
Robust Optimization ◽  
Electricity Market ◽  
Real Life ◽  
Optimization Approach ◽  
Case Scenario ◽  
Worst Case ◽  
Bidding Strategies ◽  
Wind Generators ◽  
Proposed Model ◽  
Optimal Bidding

In the recent electricity market framework, the profit of the generation companies depends on the decision of the operator on the schedule of its units, the energy price, and the optimal bidding strategies. Due to the expanded integration of uncertain renewable generators which is highly intermittent such as wind plants, the coordination with other facilities to mitigate the risks of imbalances is mandatory. Accordingly, coordination of wind generators with the evolutionary Electric Vehicles (EVs) is expected to boost the performance of the grid. In this paper, we propose a robust optimization approach for the coordination between the wind-thermal generators and the EVs in a virtual<br>power plant (VPP) environment. The objective of maximizing the profit of the VPP Operator (VPPO) is studied. The optimal bidding strategy of the VPPO in the day-ahead market under uncertainties of wind power, energy<br>prices, imbalance prices, and demand is obtained for the worst case scenario. A case study is conducted to assess the e?effectiveness of the proposed model in terms of the VPPO's profit. A comparison between the proposed model and the scenario-based optimization was introduced. Our results confirmed that, although the conservative behavior of the worst-case robust optimization model, it helps the decision maker from the fluctuations of the uncertain parameters involved in the production and bidding processes. In addition, robust optimization is a more tractable problem and does not suffer from<br>the high computation burden associated with scenario-based stochastic programming. This makes it more practical for real-life scenarios.<br>

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