Search results for "aggregate"
showing 10 items of 287 documents
Dynamic Asset Allocation Strategies Basedon Unexpected Volatility
2014
The author documents that at the aggregate stock market level, unexpected volatility is negatively related to expected future returns, and positively related to future volatility. The author demonstrates how the predictive ability of unexpected volatility can be utilized in dynamic asset allocation strategies that deliver a substantial improvement in terms of risk-adjusted performance as compared to traditional buy-and-hold strategies. In addition, the author shows that active strategies based on unexpected volatility outperform the popular active strategy with a volatility target mechanism, and have some edge over the popular market timing strategy with a 10-month simple moving average rul…
Renewable electricity producing technologies and metal depletion: A sensitivity analysis using the EROI
2015
International audience; More and more attention is being paid to renewable technologies because they are seen as a great opportunity to disengage our society from its dependence on fossil fuels. Such flow-based energy resources that rely on solarenergy are supposed to lead us toward a sustainable energy future. However, because of their high capitalintensity, renewable technologies require large amounts of matter, including both common and rare metals.These metals require energy for their production, and more specifically for their extraction. The energy costassociated with metal extraction is linked to mineral ore grade, meaning that as depletion progresses, energycost increases. In additi…
Inferring Cognitive Heterogeneity From Aggregate Choices
2020
Theories of bounded rationality often assume a rich dataset of choices from many overlapping menus, limiting their practical applicability. In contrast, we study the problem of identifying the distribution of cognitive characteristics in a population of agents from a minimal dataset that consists of aggregate choice shares from a single menu, and includes no observable covariates of any kind. With homogeneous preferences, we find that “consideration capacity” and “consideration probability” distributions can both be recovered effectively if the menu is sufficiently large. This remains true generically when tastes are heterogeneous with a known distribution. When the taste distribution is un…
Aggregate uncertainty and sectoral productivity growth: The role of credit constraints
2016
Abstract We show that an increase in aggregate uncertainty—measured by stock market volatility—reduces productivity growth more in industries that depend heavily on external finance. The mechanism at play is that during periods of high uncertainty, firms that are credit constrained switch the composition of investment by reducing productivity-enhancing investment—such as on ICT capital—which is more subject to liquidity risks (Aghion et al., 2010). The effect is larger during recessions, when financing constraints are more likely to be binding, than during expansions. Our statistical method—a difference-in-difference approach using productivity growth of 25 industries from 18 advanced econo…
Levels of 137Cs in game and soil in Opole Anomaly, Poland in 2012–2020
2021
Abstract Once deposited, radiocesium remains in the environment for a long time, and constantly enters the food chain. Over time, game species tend to accumulate 137Cs by two orders of magnitude more than farm animals. This occurs especially in places heavily contaminated, thus meat products made out of local game should be treated with caution. One of such areas, known as the Opole Anomaly, is located in South-Western Poland and represents one of most 137Cs contaminated regions across Europe after the Chernobyl accident. The aim of the study was to find out the 137Cs activity in soil and local game, the value of the soil-to-game aggregated transfer factor and to assess the effective dose o…
Regional Matching Frictions and Aggregate Unemployment
2006
This study demonstrates that a stochastic frontier approach applied to regional level data offers a convenient and interesting method to examine how regional differences in matching efficiency and structural factors contribute to aggregate unemployment. The study reveals notable and temporally stable differences in matching efficiency across travel-to-work areas in Finland. If all areas were as efficient as the most efficient one, the number of hirings would increase by about 40 per cent. This would reduce the aggregate unemployment rate from the current 8.5 per cent level to 6.0 per cent. If all the areas shared the same structural characteristics as the most favourable area, the aggregate…
Example, please! Comparing the effects of single customer reviews and aggregate review scores on online shoppers' product evaluations
2014
Many websites of online retail stores display two forms of electronic word of mouth on a single product site, namely single customer reviews and aggregate review scores. This study compares the effects of simultaneously presented single customer reviews and aggregate review scores on product evaluations of visitors of online retail stores. We hypothesize that well-argued single customer reviews should be more influential than aggregate review scores that display the mean rating of all published reviews of a product. Drawing on a 2 × 2 factorial online experiment, we show that a single customer review is effective, even when potential buyers do not perceive it as representing overall custome…
An allergen-polymeric nanoaggregate as a new tool for allergy vaccination.
2014
Parietaria pollen is one of the major causes of allergic reaction in southern Europe, affecting about 30% of all allergic patients in this area. Specifi immunotherapy is the only treatment able to modify the natural outcome of the disease by restoring a normal immunity against allergens. The preparation of allergen-solid lipid nanoparticles as delivery vehicles for therapeutic proteins, P. judaica major allergen Par j 2, was investigated. The Par j 2 allergen was expressed in a large amount in Escherichia coli and purifid to homogeneity. Its immunological properties were studied by western blotting and enzyme-linked immunosorbent assay inhibition. Solid lipid nanoparticles were obtained by …
Influence of correlations between stresses on calculated fatigue life of machine elements
1996
The correlation between components of the random stress tensor and its influence on the calculated fatigue life of machine elements were analysed. Three covariance matrices of components of biaxial stress state were considered. They were determined from measurements of strains in an element of a vibrating screen for aggregate, in the back wall of a bus, and in a welded element of excavator fittings. Calculations were made according to four criteria of multiaxial random fatigue. Cycles were counted with the rainflow method, and damage was cumulated with the Palmgren-Miner hypothesis. It was found that convariances of random stress state components strongly influence the calculated fatigue li…
A bottom-up approach for the evaluation of the flexible quota of aggregated loads
2015
The paper presents a bottom-up approach for building the aggregated load profile of numerous passive/active users connected to the low voltage electrical system. The approach is based on the Monte Carlo method and on the knowledge of the single electric and thermal loads, generators and thermal and geometrical characteristics of the building of the single end-user. The method proposed is able to differentiate the quota of flexible and not flexible aggregate load.