Assessment of metal levels of some refuse dump soils in Ghana

Abstract Concentration levels of tin (Sn), antimony (Sb), titanium (Ti), bismuth (Bi) and thallium (Tl) were assessed in refuse dump and background soils in urban (Accra and Kumasi) and rural (Sataso) communities in Ghana using a ThermoFinnigan Element 2 high resolution inductively coupled plasma mass spectrometric (HR-ICP-MS) instrument. Concentrations of the metals were lower than known normal mineral soil levels, however, based on the Igeo scale the refuse dump soils from Accra and Kumasi (urban communities) were 'Moderate to strongly polluted' with Sn and Sb while that from Sataso a rural community was classified as 'Moderately polluted' with Sn and Sb. The refuse dump soils from the urban communities were 'Unpolluted to moderately polluted' with Ti and that from the rural community was classified as 'Practically unpolluted' with Ti. All the refuse dump soils were, 'Practically unpolluted' with Bi and Tl. Differences in the pollution levels may probably be assigned to differences in population and activities in the communities

Irrational risk‑taking of professionals? The relationship between risk exposures and previous profts

The risk attitude of investors is a key factor determining fnancial asset prices and market trends. Changes in risk attitude may be due to the interference of macro-level (business cycle) and micro-level (individual experience) efects. We investigate the impact of individual experience on the subsequent risk-taking attitude of professionals via the analysis of the trading activity of 351 non-fnancial frms and (non-bank) fnancial institutions (insurance companies, fnancial intermediaries, etc.) covering 57,039 FX forward transactions in a highly volatile period between January 2008 and November 2012. Panel regressions for all frms and institutions do not show signifcant behavioral patterns. When investigating each client separately, however, we fnd that 39.7% of the clients having enough transactions to analyze statistically tend to increase their risk exposure irrationally after large gains or losses which can be the manifestation of the break-even and house-money efects well-documented in the literature for non-professionals. This irrational behavior may destroy value, so both market players and regulators should pay attention to monitor and control it

Útvonalfüggő kockázatvállalás A korábbi nyereség és a kockázatvállalás abszolút szintje közötti kapcsolat egy banki ügyfélportfólió adatbázisán

A szakirodalom alapján összefoglaltuk, hogy milyen összefüggés állhat fenn a korábbi nyereségek és a kockázatvállalási hajlandóság között, majd egy hazai banki adatbázison megvizsgáltuk, hogy a vállalati és intézményi ügyfelek elmúlt időszakban elért nyeresége mennyiben magyarázza a kockázati kitettség abszolút szintjét az EUR/HUF devizapárban 2008 és 2012 között havi időskálán. Azt kaptuk, hogy a veszteségek szignifikánsan negatív, míg a nyereségek enyhén pozitív kapcsolatban állnak a kitettség szintjével. Ez a V-alakú összefüggés konzisztens a kilátáselmélettel, különösen a küszöbérték-hatással és a házpénze-hatással. Mivel az irracionális (viselkedési) hatások egyéni és rendszerszinten is értékrombolók lehetnek, mind a befektetőknek, mind a szabályozónak érdemes figyelmet fordítaniuk erre a jelenségre

Comparison of freshwater biofilms grown on polycarbonate substrata in Lake Velence (Hungary) and Lake Mogan (Turkey)

Freshwater biofilms grown on polycarbonate substrata in Lake Velence (Hungary) and Lake Mogan (Turkey) were studied by applying total reflection X-ray fluorescence spectrometry and taxonomical techniques. Concentration of calcium, which stabilizes the structure of the exopolymer matrix, was identical in the biofilms, independently of the fact that its concentration in the lake waters differs by a factor of 2.5. Enrichment factors calculated as concentration ratios of elements (Ca, K, Fe, Mn, Zn, and Sr) measured in biofilm and water varied from 3�104 to 1.5�102. The highest enrichment factors were observed for micronutrients of manganese and iron. Although the dominant alga species were different in the Hungarian and Turkish biofilms, the enrichment factors for these two elements differ only slightly. These results demonstrate that the accumulation of these micronutrients is similar within the diatom species. The lowest enrichment factors were measured for potassium

Mastering R for quantitative finance

This book is intended for those who want to learn how to use R's capabilities to build models in quantitative finance at a more advanced level. If you wish to perfectly take up the rhythm of the chapters, you need to be at an intermediate level in quantitative finance and you also need to have a reasonable knowledge of R