A regulatory adjustment process for optimal pricing by multiproduct monopoly firms

This paper describes an incentive mechanism that is shown to enforce the use of Ramsey prices by multiproduct monopolies. The constraint given is simple. It limits information requirements on the regulatory agency to bookkeeping data of the firm. Its implementation could be easily controlled by outside courts or auditors. The process, therefore, makes use of invisible hand properties shifting the workload of welfare optimization from the regulatory agency to the regulated firm. This may lead to the ironical conclusion that regulatory commissions should fire their economists. It, however, becomes both profitable and socially beneficial for the regulated firms to employ them. *University of Bonn and M.I.T. Energy Laboratory, Cambridge, Mass.; University of Bonn and International Institute of Management, Berlin, respectively. We owe thanks to various readers of a previous version. Truman Bewley, Peter Diamond, Jonathan Goodman, Ray Hartman, Martin Hellwig, Roger Sherman, Christian von Weizs'acker and an anonymous referee will find that their suggestions have left traces in this paper

Human impact during the Bronze Age on the vegetation at Lago Lucone (northern Italy)

Lake-sediment records were used to reconstruct human impact on the landscape around Lago Lucone (45°33′N, 10°29′E, 249ma.s.l.), a former lake in the western amphitheatre system of the Lago di Garda. Presence of prehistoric human populations is attested by pile-dwelling settlements from the Early-Middle Bronze Age, with one settlement at a distance of only 100m from the coring site. Pollen, plant-macrofossil and microscopic charcoal analyses were applied to a 250cm sediment core with four dates providing the time control. A mixed oak forest that was important during the Early-Middle Holocene was cleared and replaced by open vegetation during the Bronze Age (∼2000-1100 b.c.) when open lands were estimated to have covered more than 60% of the total relevant pollen-source area. During a phase of high human impact, independent climatic proxies suggest warm and dry climatic conditions. Later, ca. 1100 b.c., palaeobotanical evidence indicates a sharp decrease in human pressure in the Lago Lucone area. The comparison with other sedimentary palaeocultural records shows that the period 1300-1100 b.c. was characterised by general declines of agricultural activities both south and north of the Alps. These declines have been previously attributed to a change towards wetter and colder climatic conditions in and around the Alps. However, the decline in human impact around Lago Lucone cannot be exclusively attributed to climatic variation. Therefore other forcing factors independent of climatic changes, such as cultural crises or changes in spatial organisation of the habitats, cannot be ruled out under the present state of knowledg

Exceptionally high levels of lead pollution in the Balkans from the Early Bronze Age to the Industrial Revolution

The Balkans are considered the birthplace of mineral resource exploitation and metalworking in Europe. However, since knowledge of the timing and extent of metallurgy in southeastern Europe is largely constrained by discontinuous archaeological findings, the long-term environmental impact of past mineral resource exploitation is not fully understood. Here we present a high resolution and continuous geochemical record from a peat bog in western Serbia, providing for the first time a clear indication of extent and magnitude of environmental pollution in this region, and a context in which to place archaeological findings. We observe initial evidence of anthropogenic lead (Pb) pollution during the earliest part of the Bronze Age (c.3600 yr before Common Era (BCE)), the earliest such evidence documented in European environmental records. A steady, almost linear increase in Pb concentration after 600 BCE, until circa 1600 CE is observed, documenting the development in both sophistication and extent of southeastern European metallurgical activity throughout Antiquity and the Medieval Period. This provides a new view on the history of mineral exploitation in Europe, with metal-related pollution not ceasing at the fall of the western Roman Empire, as was the case in western Europe. Further comparison with other Pb pollution records indicates the the amount of Pb deposited in the Balkans during the Medieval Period was if not greater, at least similar to records located close to western European mining regions, suggestive of the key role the Balkans have played in mineral resource exploitation in Europe over the last 5600 years

Early to late Holocene vegetation and fire dynamics at the treeline in the Maritime Alps

We used pollen, plant macrofossil, and charcoal records to investigate local long-term timberline shifts and changes in vegetation composition in relation to fire activity at the modern upper forest limit (ca. 2,000 m a.s.l.) in the Mont Bégo area, Maritime Alps of France and Italy. The area is an important place for Alpine archaeology because it has thousands rock-art carvings whose age cannot be directly assessed. Our new record confirms the occurrence of distinct land use phases (7,450–7,150, 6,200–4,900, and 4,250–3,700 cal bp), as suggested by earlier studies of rock art typology. Moreover, the vegetation reconstruction from macrofossils, with co-dominance of Pinus and Betula, suggests that early Holocene conditions were moister than in drier inner Alpine valleys, where Larix decidua played a more important role, both in the past as well as in modern timberline forests. After 8,000 cal bp, the timberline shifted upwards and mixed Abies alba and Pinus cembra stands established around the study site. These fire sensitive trees were finally replaced during the Bronze Age (around 4,000 cal bp) by L. decidua, which still dominates the subalpine woodlands in the area today. Our study supports the notion that while the range of A. alba has been reduced at the colder end of its natural distribution, that of L. decidua has been widened by land use changes and fire disturbances to create high alpine wood pastures

Rates of palaeoecological change can inform ecosystem restoration

Accelerations of ecosystem transformation raise concerns, to the extent that high rates of ecological change may be regarded amongst the most important ongoing imbalances in the Earth system. Here, we used high-resolution pollen and diatom assemblages and associated ecological indicators (the sum of tree and shrub pollen and diatom-inferred total phosphorus concentrations as proxies for tree cover and lake-water eutrophication, respectively) spanning the past 150 years to emphasise that rate-of-change records based on compositional data may document transformations having substantially different causes and outcomes. To characterize rates of change also in terms of other key ecosystem features, we quantified for both ecological indicators (i) the percentage of change per-unit-time, (ii) the percentage of change relative to a baseline level, and (iii) the rate of percentage change per-unit-time relative to a baseline level, taking into account the irregular spacing of palaeoecological data. These measures document how quickly specific facets of nature changed, their trajectory, as well as their status in terms of palaeoecological indicators. Ultimately, some past accelerations of community transformation may document the potential of ecosystems to rapidly recover important ecological attributes and functions. In this context, insights from palaeoecological records may be useful to accelerate ecosystem restoration

Human impacts and eutrophication patterns during the past ~200 years at Lago Grande di Avigliana (N. Italy)

A short sediment core from Lago Grande di Avigliana (Piedmont, Italy), the second most eutrophied lake in Italy, was analysed for pollen and diatoms to reconstruct land-use changes and to estimate baseline conditions for total phosphorus (TP) in the water column. Varve counts on sediment thin-sections and 210Pb, 226Ra, and 137Cs dating provided a reliable chronology for the past ~200 years. The main pollen-inferred land-use changes showed a sharp decrease of hemp retting around AD 1900, as well as a gradual change to less intensive agriculture and increasing abundance of exotic plants since AD ~1970. Diatom-inferred TP reconstructions indicated stable TP concentrations until AD ~1950, revealing baseline mesotrophic conditions (TP <25 µg l−1). After AD ~1950, TP values increased distinctly and continuously, culminating in the late 1960s with concentrations of 150 µg l−1. Subsequently, diatoms implied a linear decrease of TP, with an inferred value of 40 µg l−1 in the surface sediment sample. Comparison with instrumental TP measurements from the water column since AD 1980 showed a rapid recovery and allowed a direct validation of the diatom TP inference. However, although the TP concentration has decreased considerably, baseline conditions have not yet been reached. When compared to the limnological effects of sewage discharges on inferred-TP concentration, our results indicated that agricultural land use played a minor role in the lake's eutrophicatio

A long-term multi-proxy record of varved sediments suggests climate-induced mixing-regime shift in a large hard-water lake ~5000 years ago

The long-term terrestrial and aquatic ecosystem dynamics spanning between approximately 6200 and 4800 cal BP were investigated using pollen, diatoms, pigments, charcoal, and geochemistry from varved sediments collected in a large stratified perialpine lake, Lago Grande di Avigliana, in the Italian Alps. Marked changes were detected in diatom and pigment assemblages and in sediment composition at ~4900 cal BP. Organic matter rapidly increased and diatom assemblages shifted from oligotrophic to oligo-mesotrophic planktonic assemblages suggesting that nutrients increased at that time. Because land cover, erosion, and fire frequency did not change significantly, external nutrient sources were possibly not essential in controlling the lake-ecosystem dynamics. This is also supported by redundancy analysis, which showed that variables explaining significant amounts of variance in the diatom data were not the ones related to changes in the catchment. Instead, the broad coincidence between the phytoplankton dynamics and rising lake-levels, cooler temperatures, and stronger spring winds in the northern Mediterranean borderlands possibly points to the effects of climate change on the nutrient recycling in the lake by means of the control that climate can exert on mixing depth. We hypothesize that the increased P-release rates and higher organic-matter accumulation rates, proceeded by enhanced precipitation of iron sulphides, were possibly caused by deeper and stronger mixing leading to enhanced input of nutrients from the anoxic hypolimnion into the epilimnion. Although we cannot completely rule out the influence of minor land-cover changes due to human activities, it may be hypothesized that climate-induced cumulative effects related to mixing regime and P-recycling from sediments influenced the aquatic-ecosystem dynamics

Protective copolymers for nonviral gene vectors: synthesis, vector characterization and application in gene delivery

Uncontrolled interactions of gene vectors and drug carriers in and with an in vivo environment pose serious limitations to their applicability. In order to reduce such interactions we have designed, synthesized and applied novel copolymers of poly(ethylene glycol) and reactive linkers which are derivatized with anionic peptides after copolymerization. The anionic copolymer derivatives are used to coat positively charged nonviral gene vectors by electrostatic interactions. The copolymer coat confers to polyelectrolyte colloids of DNA and polycations steric stabilization in their minimal size and prevents salt- and serum albumin-induced aggregation. Furthermore, complement activation and the interaction with serum proteins are drastically reduced or abolished in contrast to unprotected DNA complexes. The designed vectors are compatible with the intracellular steps of gene delivery and can even enhance transfection efficiency as demonstrated with various adherent and nonadherent cell lines in culture. The synthetic concept is amenable to the principles of combinatorial chemistry and the copolymeric products may be applicable beyond gene delivery in targeted drug delivery