A Dynamic Model of the Environmental Kuznets Curve : Turning Point and Public Poliy

We set up a simple dynamic macroeconomic model with (i) polluting consump- tion and a preference for a clean environment, (ii) increasing returns in abate- ment giving rise to an EKC and (iii) sustained growth resulting from a linear final-output technology. The model captures two sorts of market failures caused by external effects associated with consumption and environmental effort. This model is employed to investigate the determinants of the turning point and the (relative) effectiveness of different public policy measures aimed at a reduction of the environmental burden. Moreover, the model offers a potential explana- tion of an N-shaped pollution-income relation. Finally, it is shown that the model is compatible with most empirical regularities on economic growth and the environment.Environmental Kuznets Curve, Pollution, Abatement, External Ef- fects, Economic Growth, Public Policy

On the evolution of snow roughness during snow fall

The deposition and attachment mechanism of settling snow crystals during snowfall dictates the very initial structure of ice within a natural snowpack. In this letter we apply ballistic deposition as a simple model to study the structural evolution of the growing surface of a snowpack during its formation. The roughness of the snow surface is predicted from the behaviour of the time dependent height correlation function. The predictions are verified by simple measurements of the growing snow surface based on digital photography during snowfall. The measurements are in agreement with the theoretical predictions within the limitations of the model which are discussed. The application of ballistic deposition type growth models illuminates structural aspects of snow from the perspective of formation which has been ignored so far. Implications of this type of growth on the aerodynamic roughness length, density, and the density correlation function of new snow are discusse

Micrometeorological processes driving snow ablation in an Alpine catchment

Mountain snow covers typically become patchy over the course of a melting season. The snow pattern during melt is mainly governed by the end of winter snow depth distribution and the local energy balance. The objective of this study is to investigate micrometeorological processes driving snow ablation in an Alpine catchment. For this purpose we combine a meteorological model (ARPS) with a fully distributed energy balance model (Alpine3D). Turbulent fluxes above melting snow are further investigated by using data from eddy-correlation systems. We compare modelled snow ablation to measured ablation rates as obtained from a series of Terrestrial Laser Scanning campaigns covering a complete ablation season. The measured ablation rates indicate that the advection of sensible heat causes locally increased ablation rates at the upwind edges of the snow patches. The effect, however, appears to be active over rather short distances except for very strong wind conditions. Neglecting this effect, the model is able to capture the mean ablation rates for early ablation periods but strongly overestimates snow ablation once the fraction of snow coverage is below a critical value. While radiation dominates snow ablation early in the season, the turbulent flux contribution becomes important late in the season. Simulation results indicate that the air temperatures appear to overestimate the local air temperature above snow patches once the snow coverage is below a critical value. Measured turbulent fluxes support these findings by suggesting a stable internal boundary layer close to the snow surface causing a strong decrease of the sensible heat flux towards the snow cover. Thus, the existence of a stable internal boundary layer above a patchy snow cover exerts a dominant control on the timing and magnitude of snow ablation for patchy snow covers.<br/

Is the gamma risk of options insurable?

In this article we analyze the risk associated with hedging written call options. We introduce a way to isolate the gamma risk from other risk types and present its loss distribution, which has heavy tails. Moving to an insurance point of view, we define a loss ratio that we find to be well behaved with a slightly negative correlation to traditional lines of insurance business, offering diversification opportunities. The tails of the loss distribution are shown to be much fatter than those of the underlying stock returns. We also show that badly estimated volatility, in the Black-Scholes model, leads to considerably biased values for the replicating portfolio. Operational risk is defined as caused by imperfect delta hedging and is found to be limited in today's markets where the autocorrelation of stock returns is small.Option; Insurance; Risk

Preserving Value in the Post-BAPCPA Era — An Empirical Study

Through the use of a multivariate regression model, this article studies the effect on debtor reorganization values of the shortened reorganization timeframe imposed by the Bankruptcy Abuse Prevention and Consumer Protection Act (“BAPCPA”). The study shows that BAPCPA is positively correlated at a statistically significant level with higher reorganization recoveries. This result is attributed to the increased proportion of prepackaged and prenegotiated bankruptcies observed in the post-2005 era, as these “fast-track” bankruptcy cases entail lower costs and better preserve the firm’s value

Transpiration and water uptake of Senecio medley-woodii and Aloe jucunda under changing environmental conditions: measurements with a potometric water-budget-meter

Transpiration, water uptake by the roots and CO2 exchange of two leaf succulents, Senecio medleywoodii (Asteraceae) and Aloe jucunda (Asphodeliaceae), were monitored simultaneously and continuously with a gas exchange cuvette combined with an apparatus to quantify water uptake (= waterbudget- meter). Measurements, which are primarily valid for plants with a sufficient water supply, were made with the same plant for up to 29 consecutive days. Ambient air temperature varied between 17 and 35 °C with a constant dewpoint temperature of 13°C of the ambient air and a 12 h photoperiod at 400-500µmol m−2s−1 photon irradiance. The net water flux (Jw(net)=water uptake-transpiration) and the water balance (Jw(net) integrated for a timespan) were calculated. Various tests were made to determine the accuracy of the measurements made with this rather complex equipment. In most cases the errors for transpiration and uptake rates were much lower than 8% determined under the conditions of drastically (about 10 K per 30 min) increased or decreased ambient air temperatures. The experimental set-up proved to be a most valuable tool to determine and analyse interactions between transpiration and water uptake, changes in plant water status and the buffering of negative Jwnet). Increasing the temperature of ambient air resulted, for both species investigated, in a quick and considerably enhanced transpiration, but there was only a minor impact on water uptake. Water loss exceeding uptake was buffered by internal water reserves which were refilled within about 1 d after the plant was relieved of heat and drought stress caused by a period of high ambient air temperatures and high water vapour saturation deficits of the air. Repeated simulation of such stress periods showed that the absolute values of transpiration and the water uptake for 24 h can vary, but the diurnal course of the values showed the same pattern if the environmental conditions were identical. Such standardized diurnal transpiration and water uptake curves could be very useful for the validation of mathematical models used to describe plant water relation

Black carbon contributes to organic matter in young soils in the Morteratsch proglacial area (Switzerland)

Most glacier forefields of the European Alps are being progressively exposed since the glaciers reached their maximum expansion in the 1850s. Global warming and climate changes additionally promote the exposure of sediments in previously glaciated areas. In these proglacial areas, initial soils have started to develop so that they may offer a continuous chronosequence from 0 to 150-yr-old soils. The build-up of organic matter is an important factor of soil formation, and not only autochthonous but also distant sources might contribute to its accumulation in young soils and surfaces of glacier forefields. Only little is known about black carbon in soils that develop in glacier forefields, although charred organic matter could be an important component of organic carbon in Alpine soils. The aim of our study was to examine whether black carbon (BC) is present in the initial soils of a proglacial area, and to estimate its relative contribution to soil organic matter. We investigated soil samples from 35 sites distributed over the whole proglacial area of Morteratsch (Upper Engadine, Switzerland), covering a chronosequence from 0 to 150 yr. BC concentrations were determined in fine earth using the benzene polycarboxylic acid (BPCA) marker method. We found that charred organic matter occurred in the whole area, and that it was a main compound of soil organic matter in the youngest soils, where total Corg concentrations were very low. The absolute concentrations of BC in fine earth were generally low but increased in soils that had been exposed for more than 40 yr. Specific initial microbial communities may profit from this additional C source during the first years of soil evolution and potentially promote soil development in its early stage

Long-term Cropping Systems and Tillage Management Effects on Soil Organic Carbon Stock and Steady State Level of C Sequestration Rates in a Semiarid Environment

A calcareous and clayey xeric Chromic Haploxerepts of a long-term (19 years) experimental site in Sicily (Italy) with different land use management and cropping systems were sampled (0-15 cm depth) to study their effect on soil aggregate stability and associated organic carbon (SOC). The experimental site had three tillage managements (no till [NT], dual-layer [DL] and conventional tillage [CT]) and two cropping systems (durum wheat mono-cropping [W] and durum wheat/faba bean rotation [WB]). The whole site covered an area of 4440 m2 with individual plots having 370 m2. The soil was ploughed during the experiment. Samples (2 – 4 kg each) were taken before and after the experiment. The annually sequestered SOC with W was 2.75 times higher than with WB and higher SOC concentrations were measured. The NT management system was the most effective in SOC sequestration whereas with DL no C was sequestered. The differences in SOC concentrations between NT and CT were surprisingly small. Cumulative C input of all cropping and tillage systems and the annually sequestered SOC indicated that a steady state occurred at a sequestration rate of 7.4 Mg C ha-1 yr-1. Independent of the cropping systems, most of the SOC was stored in the silt and clay fraction. This fraction had a high N content which is typical for organic matter interacting strongly with minerals. Macro-aggregates (&gt; 250µm) were influenced by the treatments whereas the finest fractions were not. DL reduced the SOC in macro-aggregates while NT and CT gave rise to much higher SOC contents

Granularzelltumor des Larynx

Zusammenfassung: Granularzelltumoren (GZT) sind subkutan oder submukös gelegene, gutartige Tumoren neurogenen Ursprungs. Sie treten häufig im Kopf-Hals-Bereich auf, insbesondere in der Zunge. Bisher wurden etwa 200 laryngeale GZT beschrieben. Meist sind dabei die Stimmlippen und die posteriore Glottis betroffen. Eine Unterscheidung von einer chronischen Entzündung oder einem Malignom ist nur mittels Biopsie möglich. Als Therapie der Wahl wird die vollständige Exzision empfohlen, wobei Tumorausdehnung und zu erwartende Morbidität die Radikalität des Vorgehens bestimmen. Bei vollständiger Entfernung sind Rezidive selte