995 research outputs found
Information Markets and the Comovement of Asset Prices
Traditional asset pricing models predict that covariance between prices of different assets should be lower than what we observe in the data. This model generates this high covariance within a rational expectations framework by introducing markets for information about asset payoffs. When information is costly, rational investors will not buy information about all assets; they will learn about a subset. Because information production has high fixed costs, competitive producers charge more for low-demand information than for high-demand information. A price that declines in quantity makes investors want to purchase a common subset of information. If investors price many assets using a common subset of information, then a shock to one signal is passed on as a common shock to many asset prices. These common shocks to asset prices generate `excess covariance.' The cross-sectional and time-series properties of asset price covariance are consistent with this explanation
Media Frenzies in Markets for Financial Information
Emerging equity markets witness occasional surges in the price level (frenzies) and increases in cross-market price dispersion (herds), accompanied by a flood of media coverage. Complementarity in information acquisition can explain these anomalies. Because information has a high fixed cost of production, its equilibrium price is low when quantity is high. Investors all buy the same information because it has the lowest price. By lowering risk, information raises the asset's price. Given two identical assets, investors herd: one price is higher because abundant information about that asset reduces its payoff risk. Transitions between low-information/low-asset-price and high-information/high-asset-price equilibria create price paths resembling periodic frenzies. Using equity data and a new panel data set of news counts for 23 emerging markets, the results show that when asset market volatility increases, news coverage intensifies, and that more news is correlated with higher asset prices and higher cross-market price dispersion
Inventory Existing Risk Scenarios
This report provides an inventory of existing hazard data, spatial data sets and socioeconomic projections to process scenario information and future risk projections for the ENHANCE case studies. As a basis for this inventory, we conducted a small survey across the EHNHANCE cases study on their data needs. Table 1.1 provides a preliminary overview of the hazard- and socioeconomic data and scenario's required within the different case studies. This overview on the case study data needs and the data availability within the different case study partners, was discussed during the project meetings in Venice, May 2013 and Ispra (September 2013).
During the meeting in Ispra, the case studies were offered a 2 days hands on workshop on how to use scenario and risk data or their case studies. This workshop was offered by IVM and JRC.
Since the ENHANCE project follows a risk based approach, we similarly have focused this report on (1) data and projections for different types of natural hazards (Chapter 2) and (2) trends in socioeconomic factors that influence exposure and vulnerability to the natural hazard (Chapter 3). In addition, we have specifically outlined methods to process socioeconomic scenarios (Chapter 4) and probabilistic methods (Chapter 5) to describe extreme events with a very low probability.
The main objectives of this report are to:
- Provide an inventory of dynamic hazard scenarios at the pan-European scale, based on existing information at JRC or other institutes;
- Provide an inventory of socioeconomic data and projections in Europe as well as some global outlook projections, possibly relevant for ENHANCE;
- Develop a probabilistic risk framework for identifying probabilities of extreme events in the case studies
Postprint "Who believes in the storybook image of the scientist?" accepted for publication in Accountability in Research
Do lay people and scientists themselves recognize that scientists are human and therefore prone to human fallibilities such as error, bias, and even dishonesty? In a series of three experimental studies and one correlational study (total N = 3,278) we found that the ‘storybook image of the scientist’ is pervasive: American lay people and scientists from over 60 countries attributed considerably more objectivity, rationality, open-mindedness, intelligence, integrity, and communality to scientists than other highly-educated people. Moreover, scientists perceived even larger differences than lay people did. Some groups of scientists also differentiated between different categories of scientists: established scientists attributed higher levels of the scientific traits to established scientists than to early-career scientists and PhD students, and higher levels to PhD students than to early-career scientists. Female scientists attributed considerably higher levels of the scientific traits to female scientists than to male scientists. A strong belief in the storybook image and the (human) tendency to attribute higher levels of desirable traits to people in one’s own group than to people in other groups may decrease scientists’ willingness to adopt recently proposed practices to reduce error, bias and dishonesty in science
LandbouwOnderzoek (LO): Portfolioanalyse, Resultaten & Effecten
Het IWT is uitvoerder van het programma LandbouwOnderzoek (LO). Dat programma is in 2005 ontstaan, na goedkeuring van de Vlaamse overheid, om toegepast collectief onderzoek voor de land- en tuinbouwsector te financieren. Jaarlijks kunnen uitvoerders (universiteiten, hogescholen, praktijkcentra en onderzoekscentra), alleen of in consortium, voorstellen indienen om kennis te ontwikkelen, te bundelen en te vertalen voor bedrijven uit de Vlaamse primaire sector (en distributie en opslag). De activiteiten in het programma richten zich uitsluitend op de primaire plantaardige productie, evenals de distributie en opslag van deze producten. Het onderzoeksbureau Dialogic heeft de studie naar het portfolio, de werking, resultaten en effecten van LandbouwOnderzoek als instrument toegewezen gekregen. De studie is bovendien gelijktijdig uitgevoerd met het verder uitwerken van de hervorming van het LO-programma door het IWT. De inzichten worden verwerkt in de vernieuwde aanpak van LandbouwOnderzoek naar Landbouw-trajecten
Water dynamics in the seven African countries of Dutch policy focus: Benin, Ghana, Kenya, Mali, Mozambique, Rwanda, South Sudan: report on Benin
ASC – Publicaties niet-programma gebonde
Effect of crude protein concentration and dietary electrolyte balance on litter quality, foot pad dermatitis, growth performance and processing yields in two medium heavy turkey hybrids
1. An experiment was conducted to investigate the effect of crude protein (CP) concentration and dietary electrolyte balance (DEB) on growth performance, processing yields, litter quality and foot pad dermatitis (FPD) in male turkeys from two commercial hybrids. Soya bean meal was replaced by vegetable protein sources selected for lower K concentrations to lower DEB in order to improve litter quality and subsequent quality of foot pads.2. Effects of CP on litter friability and wetness were not consistent during the production period. FPD in turkeys fed on diets with low CP was significantly lower than FPD in turkeys fed on diets with high CP until 84 d. Growth performance was adversely affected at low CP. Processing yields were not affected by CP.3. Litter was significantly dryer in pens of turkeys fed on diets with low DEB than in pens of turkeys fed on diets with high DEB. FPD in turkeys fed on diets with low DEB was significantly lower than in turkeys fed on diets with high DEB. Growth performance and processing yields were adversely affected at low DEB.4. FPD in turkey hybrid A was higher than in turkey hybrid B at 28 d of age. Thereafter, no differences in FPD between turkey hybrids were observed. Growth performance and processing yields were not affected by turkey hybrid.5. Overall, a significant interaction effect of CP × DEB was observed for FCR: in turkeys fed on the high DEB treatment, FCR of turkeys fed on the high CP diets was lower than FCR of turkeys fed on the low CP (LCP) diets whereas on the low DEB treatment, FCR was not affected by CP treatment.6. It was concluded that litter quality can be improved and FPD may be decreased in turkeys fed on diets containing lower CP and DEB levels.<br/
Computational Model for Urban Growth Using Socioeconomic Latent Parameters
Land use land cover changes (LULCC) are generally modeled using multi-scale
spatio-temporal variables. Recently, Markov Chain (MC) has been used to model
LULCC. However, the model is derived from the proportion of LULCC observed over
a given period and it does not account for temporal factors such as
macro-economic, socio-economic, etc. In this paper, we present a richer model
based on Hidden Markov Model (HMM), grounded in the common knowledge that
economic, social and LULCC processes are tightly coupled. We propose a HMM
where LULCC classes represent hidden states and temporal fac-tors represent
emissions that are conditioned on the hidden states. To our knowledge, HMM has
not been used in LULCC models in the past. We further demonstrate its
integration with other spatio-temporal models such as Logistic Regression. The
integrated model is applied on the LULCC data of Pune district in the state of
Maharashtra (India) to predict and visualize urban LULCC over the past 14
years. We observe that the HMM integrated model has improved prediction
accuracy as compared to the corresponding MC integrated modelComment: 12 page
Soil trace gas fluxes along orthogonal precipitation and soil fertility gradients in tropical lowland forests of Panama
Tropical lowland forest soils are significant sources and sinks of trace gases. In order to model soil trace gas flux for future climate scenarios, it is necessary to be able to predict changes in soil trace gas fluxes along natural gradients of soil fertility and climatic characteristics. We quantified trace gas fluxes in lowland forest soils at five locations in Panama, which encompassed orthogonal precipitation and soil fertility gradients. Soil trace gas fluxes were measured monthly for 1 (NO) or 2 (CO2, CH4, N2O) years (2010–2012) using vented dynamic (for NO only) or static chambers with permanent bases. Across the five sites, annual fluxes ranged from 8.0 to 10.2 Mg CO2-C, −2.0 to −0.3 kg CH4-C, 0.4 to 1.3 kg N2O-N and −0.82 to −0.03 kg NO-N ha−1 yr−1. Soil CO2 emissions did not differ across sites, but they did exhibit clear seasonal differences and a parabolic pattern with soil moisture across sites. All sites were CH4 sinks; within-site fluxes were largely controlled by soil moisture, whereas fluxes across sites were positively correlated with an integrated index of soil fertility. Soil N2O fluxes were low throughout the measurement years, but the highest emissions occurred at a mid-precipitation site with high soil N availability. Net negative NO fluxes at the soil surface occurred at all sites, with the most negative fluxes at the low-precipitation site closest to Panama City; this was likely due to high ambient NO concentrations from anthropogenic sources. Our study highlights the importance of both short-term (climatic) and long-term (soil and site characteristics) factors in predicting soil trace gas fluxes
Tropical Andean Forests Are Highly Susceptible to Nutrient Inputs - Rapid Effects of Experimental N and P Addition to an Ecuadorian Montane Forest
Tropical regions are facing increasing atmospheric inputs of nutrients, which will have unknown consequences for the structure and functioning of these systems. Here, we show that Neotropical montane rainforests respond rapidly to moderate additions of N (50 kg ha−1 yr−1) and P (10 kg ha−1 yr−1). Monitoring of nutrient fluxes demonstrated that the majority of added nutrients remained in the system, in either soil or vegetation. N and P additions led to not only an increase in foliar N and P concentrations, but also altered soil microbial biomass, standing fine root biomass, stem growth, and litterfall. The different effects suggest that trees are primarily limited by P, whereas some processes—notably aboveground productivity—are limited by both N and P. Highly variable and partly contrasting responses of different tree species suggest marked changes in species composition and diversity of these forests by nutrient inputs in the long term. The unexpectedly fast response of the ecosystem to moderate nutrient additions suggests high vulnerability of tropical montane forests to the expected increase in nutrient inputs
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