Search results for "Normal"
showing 10 items of 2571 documents
Effective Field Theory
2015
Effective field theories (EFTs) are a highly important topic in Quantum Field Theory. Here we are going to shortly present some important highlights as well as the renormalization group equations for the Wilson coefficients. Afterwards we shall focus on one illustrative example and present the \(\textit{matching}\) procedure at the one-loop level. The infrared behaviour of EFTs is also covered with this example.
Temperature and doping dependence of normal state spectral properties in a two-orbital model for ferropnictides
2016
Using a second-order perturbative Green's functions approach we determined the normal state single-particle spectral function $A(\vec{k},\omega)$ employing a minimal effective model for iron-based superconductors. The microscopic model, used before to study magnetic fluctuations and superconducting properties, includes the two effective tight-binding bands proposed by S.Raghu et al. [Phys. Rev. B 77, 220503 (R) (2008)], and intra- and inter-orbital local electronic correlations, related to the Fe-3d orbitals. Here, we focus on the study of normal state electronic properties, in particular the temperature and doping dependence of the total density of states, $A(\omega)$, and of $A(\vec{k},\o…
Introduction: Treasures and Magic
2012
Treasures were magical. Until the nineteenth century, buried treasures were shrouded with intricate webs of narratives. Most of these narratives had magical elements. Vestiges of that treasure magic have survived. In the summer of 2009, while I worked on this book, the spectacular discovery of an Anglo-Saxon treasure in Staffordshire made headlines. Metal detector enthusiast Terry Herbert, who had searched for treasure troves in vain for years, unearthed about 1500 gold and silver objects dating back to the seventh century. In an interview, Herbert told the press: I have this phrase that I say sometimes — ‘spirits of yesteryear take me where the coins appear’ — but on that day I changed coi…
The cost of equity and exchange listing evidence from the French stock market
1997
We reconsider the behaviour of prices around the period close to the listing on the Marché à Règlement Mensuel (RM). First, an event study based on a sample of 60 firms has been set up to test the existence of the exchange listing effect on the French market. Then we discuss and test the financial reasons which can justify abnormal returns around the announcement day and the day of the listing. We explore four reasons to explain the impact of the stock exchange listings: one is the informative content of the operation which induces an upward revision of the future earnings. Three other hypotheses rely on a decrease in the discount rate originated by less risky cash flows, an increase in tra…
Vegetation Types Mapping Using Multi-Temporal Landsat Images in the Google Earth Engine Platform
2021
Vegetation Types (VTs) are important managerial units, and their identification serves as essential tools for the conservation of land covers. Despite a long history of Earth observation applications to assess and monitor land covers, the quantitative detection of sparse VTs remains problematic, especially in arid and semiarid areas. This research aimed to identify appropriate multi-temporal datasets to improve the accuracy of VTs classification in a heterogeneous landscape in Central Zagros, Iran. To do so, first the Normalized Difference Vegetation Index (NDVI) temporal profile of each VT was identified in the study area for the period of 2018, 2019, and 2020. This data revealed strong se…
Relationships between climatic parameters and forest vegetation: application to burned area in Alicante (Spain)
2000
Abstract The main aims of this study is to examine the variability of normalized difference vegetation index (NDVI) on forest vegetation in Alicante (Spain) between 1984 and 1994 and to analyse the influence of climatic parameters in the regeneration of forest areas burned by fires. The zone of study is located between XUTM (m) 730400-760400 and YUTM (m) 4274000-4304000 and is characterised by a great topographic complexity that leads to diverse microclimatic conditions. In this area, the maximum annual rainfall of the Valencian Community is recorded, reaching 850 mm of average annual rainfall ( Belda, 1997 ). We examined the spatial and temporal analyse of rainfall and soil moisture over t…
Spillovers from the oil sector to the housing market cycle
2017
We assess the spillovers from the oil sector to the housing market cycle using quarterly data for 20 net oil-exporting and -importing industrial countries, and employing continuous- and discrete-time duration models. We do not uncover a statistically significant difference in the average duration of booms and normal times in the housing markets of those net oil-importers and net oil-exporters. Similarly, the degree of exposure to commodity price fluctuations does not seem to significantly affect the housing market cycle. However, we find that housing booms are shorter when oil prices increase than housing busts when oil prices decrease. We also show that the net oil-importers are more vulne…
Market efficiency and price discovery relationships between spot, futures and forward prices: the case of the Iberian Electricity Market (MIBEL)
2016
ABSTRACTThis paper analyses the relationships between prices from three different markets within the Spanish zone of the Iberian Electricity Market (MIBEL), namely futures, spot and over the counter (OTC) forward markets. The study focuses on three items: (i) contrasting the Weak-form efficiency hypothesis of the markets involved in the study, (ii) analysing the Semi-strong-form efficient market hypothesis (EMH) of the MIBEL futures market and (iii) examining the price discovery relationships between the series of prices of the considered markets.The empirical results confirm that 1-month-, 1-quarter-, 1-year-ahead futures and spot markets satisfy, generally, the Weak-form efficiency hypoth…
Interest Rate Sensitivity of Spanish Industries: A Quantile Regression Approach
2015
This paper examines the degree of interest rate exposure of Spanish industries for the period 1993–2012 using the quantile regression methodology. The empirical results show that the Spanish stock market exhibits a significant level of interest rate sensitivity, although there are notable differences across industries and over time. In addition, the impact of changes in interest rates on industry equity returns tends to be more pronounced in extreme market conditions, i.e. during crises or bubbles in stock markets, than in normal periods. This finding may be related to herding behavior of stock investors during periods of market stress.
Weak versus strong dominance of shrinkage estimators
2021
We consider the estimation of the mean of a multivariate normal distribution with known variance. Most studies consider the risk of competing estimators, that is the trace of the mean squared error matrix. In contrast we consider the whole mean squared error matrix, in particular its eigenvalues. We prove that there are only two distinct eigenvalues and apply our findings to the James–Stein and the Thompson class of estimators. It turns out that the famous Stein paradox is no longer a paradox when we consider the whole mean squared error matrix rather than only its trace.