Search results for "markets"
showing 10 items of 332 documents
Top-of-Atmosphere Retrieval of Multiple Crop Traits Using Variational Heteroscedastic Gaussian Processes within a Hybrid Workflow.
2021
In support of cropland monitoring, operational Copernicus Sentinel-2 (S2) data became available globally and can be explored for the retrieval of important crop traits. Based on a hybrid workflow, retrieval models for six essential biochemical and biophysical crop traits were developed for both S2 bottom-of-atmosphere (BOA) L2A and S2 top-of-atmosphere (TOA) L1C data. A variational heteroscedastic Gaussian process regression (VHGPR) algorithm was trained with simulations generated by the combined leaf-canopy reflectance model PROSAILat the BOA scale and further combined with the Second Simulation of a Satellite Signal in the Solar Spectrum (6SV) atmosphere model at the TOA scale. Establishe…
A novel method to predict dark diversity using unconstrained ordination analysis
2019
[Questions] Species pools are the product of complex ecological and evolutionary mechanisms, operating over a range of spatial scales. Here, we focus on species absent from local sites but with the potential to establish within communities — known as dark diversity. Methods for estimating dark diversity are still being developed and need to be compared, as well as tested for the type, and amount, of reference data needed to calibrate these methods. [Location] South Bohemia (48°58′ N, 14°28′ E) and Železné Hory (49°52′ N, 15°34′ E), Czech Republic. [Method] We compared a widely accepted algorithm to estimate species pools (Beals smoothing index, based on species co-occurrence) against a nove…
Coupling News Sentiment with Web Browsing Data Improves Prediction of Intra-Day Price Dynamics
2015
The new digital revolution of big data is deeply changing our capability of understanding society and forecasting the outcome of many social and economic systems. Unfortunately, information can be very heterogeneous in the importance, relevance, and surprise it conveys, affecting severely the predictive power of semantic and statistical methods. Here we show that the aggregation of web users' behavior can be elicited to overcome this problem in a hard to predict complex system, namely the financial market. Specifically, our in-sample analysis shows that the combined use of sentiment analysis of news and browsing activity of users of Yahoo! Finance greatly helps forecasting intra-day and dai…
The habitual nature of food purchases at the supermarket: Implications for policy making
2020
Abstract Supermarkets have become the most important provider of food products worldwide. However, empirical evidence about how consumers make their food purchase decisions in this environment is still scarce. The present field study aimed to: i) explore how people make their in-store food purchases, and ii) identify the information they search for when making those purchases. Consumers (n = 144) were intercepted when entering the facilities of three supermarkets in two Uruguayan cities. They were asked to wear a mobile eye-tracker while they made their purchases as they normally do. The great majority of the consumers bought at least one food product or beverage (92%) and, on average, exam…
Motives for buying local, organic food through English box schemes
2018
Purpose The purpose of this paper is to explain the growing interest of English consumers in local organic food sold through box schemes, by providing insights into the motives of customers of such schemes and examining the relationship with their awareness about problems of the agro-food system. Design/methodology/approach A mixed methods approach combined in-depth interviews with 22 box scheme customers with a quantitative survey of 416 consumers, analysed by means of principal component analysis and an ordered logit model. Findings Consumers of small local organic box schemes in England are both altruistically and hedonistically motivated. This includes a strong political motivation to …
Mineral profiles of legumes and fruits through partial least squares energy dispersive X-ray fluorescence
2019
Abstarct Energy dispersive X-ray fluorescence (ED-XRF) has been employed for the determination of mineral elements in 15 varieties of legumes and 14 cherry samples. ED-XRF signals directly obtained from pulverized samples were modelized by partial least squares (PLS) using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) of a selected number of samples, after microwave assisted acid digestion, as reference data. Models were built to predict the concentration of Al, Ca, Cu, Fe, K, Mg, P, Sr and Zn. Average concentrations predicted were 6, 930, 7, 40, 6400, 990, 2100, 4 and 15 μg g−1 for Al, Ca, Cu, Fe, K, Mg, P, Sr and Zn, respectively with relative errors from 7 till 26%. …
Correlation between school dropout and gross domestic product in the emerging countries of Central and Eastern Europe
2020
By school dropout is meant leaving the educational system, regardless of the reached level, before obtaining a qualification or a complete proffesional training or before the end of the study cycle started (Doron & Parot, 2006). Although there are numerous researches on school dropout, we consider that it is necessary to study the relationship it has with the level of development of a country, in order to identify new causes and possible solutions to this phenomenon. In this study we included seven emerging countries of Central and Eastern Europe: Bulgaria, Czech Republic, Poland, Romania, Slovakia, Slovenia and Hungary. Thus, we analyzed the correlation between the annual gross domesti…
The Interactions between COVID-19 Cases in the USA, the VIX Index and Major Stock Markets
2021
With this study, we aimed to determine (1) the effect of the daily new cases and deaths due to the COVID-19 pandemic in the United States on the CBOE volatility index (VIX index) and (2) the effect of the VIX index on the major stock markets during the early stage of the pandemic period. To do this, we collected and analysed the daily new cases and death numbers during the COVID-19 pandemic period in the United States and the country indexes of the USA (DJI), Germany (DAX), France (CAC40), England (FTSE100), Italy (MIB), China (SSEC) and Japan (Nikkei225) to determine the impact of the VIX index on the major stock markets. We then subjected this data to the Johansen co-integration test and …
Estructura de la bolsa española e introducción del mercado de activos derivados sobre el IBEX-35
2001
-Jose.E.Farinos@uv.es -Matilde.Fernandez@uv.es La controversia acerca de si la implantación y negociación de activos derivados afecta a la estabilidad de los respectivos mercados de contado perdura desde hace más de dos décadas. En este trabajo abordamos la problemática anterior desde una nueva perspectiva. Concretamente, analizamos el impacto que sobre la estructura del mercado bursátil ha podido tener la introducción de los mercados de activos derivados sobre el IBEX-35. Para ello, definimos e identificamos la estructura del mercado bursátil para el periodo de estudio, y, a continuación, analizamos el efecto que sobre la misma ha tenido la aparición de los nuevos mercados de derivados. Nu…
Value preserving portfolio strategies and the minimal martingale measure
1998
We consider some relations between the minimal martingale measure and the value preserving martingale measure in a continuous-time securities market. Under the assumption of continuous share prices we show that under a structure condition both these martingale measures exist and indeed coincide. This however does not mean that the corresponding concepts of value preserving portfolio strategies and (local) risk minimisation in the area of option hedging in incomplete markets are identical.