WorldWideScience

Sample records for extraterrestrial physics garching

  1. Extraterrestrial Solar Neutrino Physics

    CERN Document Server

    Hwang, W-Y Pauchy

    2010-01-01

    We examine the scope of extraterrestrial solar neutrino physics, i.e. solar neutrino physics that could be carried out outside the Earth. We find that, among others, the reactions induced by the ^8B solar neutrinos, in view of the sole high energy nature (E_nu^max=14.03MeV), are most interesting in the solar environment. Two types of experiments are considered - the chemical compositions of the geology type and the matter-enhanced oscillations when the Sun-Venus-Earth eclipse, or the Sun-Mercury-Earth eclipse, occurs or the Satellite experiments (likely to be different from the "day-night" effect on the Earth). These experiments are not beyond current technology limits. In view of the weak-interaction nature, they are likely to be the precision experiments of the next generation or even beyond.

  2. Physical and Chemical Aspects of Fire Suppression in Extraterrestrial Environments

    Science.gov (United States)

    Takahashi, F.; Linteris, G. T.; Katta, V. R.

    2001-01-01

    A fire, whether in a spacecraft or in occupied spaces on extraterrestrial bases, can lead to mission termination or loss of life. While the fire-safety record of US space missions has been excellent, the advent of longer duration missions to Mars, the moon, or aboard the International Space Station (ISS) increases the likelihood of fire events, with more limited mission termination options. The fire safety program of NASA's manned space flight program is based largely upon the principles of controlling the flammability of on-board materials and greatly eliminating sources of ignition. As a result, very little research has been conducted on fire suppression in the microgravity or reduced-gravity environment. The objectives of this study are: to obtain fundamental knowledge of physical and chemical processes of fire suppression, using gravity and oxygen concentration as independent variables to simulate various extraterrestrial environments, including spacecraft and surface bases in Mars and moon missions; to provide rigorous testing of analytical models, which include comprehensive descriptions of combustion and suppression chemistry; and to provide basic research results useful for technological advances in fire safety, including the development of new fire-extinguishing agents and approaches, in the microgravity environment associated with ISS and in the partial-gravity Martian and lunar environments.

  3. Multivariate GARCH models

    DEFF Research Database (Denmark)

    Silvennoinen, Annastiina; Teräsvirta, Timo

    This article contains a review of multivariate GARCH models. Most common GARCH models are presented and their properties considered. This also includes nonparametric and semiparametric models. Existing specification and misspecification tests are discussed. Finally, there is an empirical example...... in which several multivariate GARCH models are fitted to the same data set and the results compared....

  4. Multivariate GARCH models

    DEFF Research Database (Denmark)

    Silvennoinen, Annastiina; Teräsvirta, Timo

    This article contains a review of multivariate GARCH models. Most common GARCH models are presented and their properties considered. This also includes nonparametric and semiparametric models. Existing specification and misspecification tests are discussed. Finally, there is an empirical example...... in which several multivariate GARCH models are fitted to the same data set and the results compared....

  5. Improving Garch Volatility Forecasts

    NARCIS (Netherlands)

    Klaassen, F.J.G.M.

    1998-01-01

    Many researchers use GARCH models to generate volatility forecasts. We show, however, that such forecasts are too variable. To correct for this, we extend the GARCH model by distinguishing two regimes with different volatility levels. GARCH effects are allowed within each regime, so that our model

  6. Limit experiments of GARCH

    CERN Document Server

    Buchmann, Boris; 10.3150/10-BEJ328

    2012-01-01

    GARCH is one of the most prominent nonlinear time series models, both widely applied and thoroughly studied. Recently, it has been shown that the COGARCH model (which was introduced a few years ago by Kl\\"{u}ppelberg, Lindner and Maller) and Nelson's diffusion limit are the only functional continuous-time limits of GARCH in distribution. In contrast to Nelson's diffusion limit, COGARCH reproduces most of the stylized facts of financial time series. Since it has been proven that Nelson's diffusion is not asymptotically equivalent to GARCH in deficiency, in the present paper, we investigate the relation between GARCH and COGARCH in Le Cam's framework of statistical equivalence. We show that GARCH converges generically to COGARCH, even in deficiency, provided that the volatility processes are observed. Hence, from a theoretical point of view, COGARCH can indeed be considered as a continuous-time equivalent to GARCH. Otherwise, when the observations are incomplete, GARCH still has a limiting experiment, which we ...

  7. GARCH Modelling of Cryptocurrencies

    Directory of Open Access Journals (Sweden)

    Jeffrey Chu

    2017-10-01

    Full Text Available With the exception of Bitcoin, there appears to be little or no literature on GARCH modelling of cryptocurrencies. This paper provides the first GARCH modelling of the seven most popular cryptocurrencies. Twelve GARCH models are fitted to each cryptocurrency, and their fits are assessed in terms of five criteria. Conclusions are drawn on the best fitting models, forecasts and acceptability of value at risk estimates.

  8. Realized Beta GARCH

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Lunde, Asger; Voev, Valeri Radkov

    2014-01-01

    We introduce a multivariate generalized autoregressive conditional heteroskedasticity (GARCH) model that incorporates realized measures of variances and covariances. Realized measures extract information about the current levels of volatilities and correlations from high-frequency data, which...... is particularly useful for modeling financial returns during periods of rapid changes in the underlying covariance structure. When applied to market returns in conjunction with returns on an individual asset, the model yields a dynamic model specification of the conditional regression coefficient that is known...... as the beta. We apply the model to a large set of assets and find the conditional betas to be far more variable than usually found with rolling-window regressions based exclusively on daily returns. In the empirical part of the paper, we examine the cross-sectional as well as the time variation...

  9. How likely is extraterrestrial life?

    CERN Document Server

    Halley, J Woods

    2012-01-01

    What does existing scientific knowledge about physics, chemistry, meteorology and biology tell us about the likelihood of extraterrestrial life and civilizations? And what does the fact that there is currently no credible scientific evidence for the existence of extraterrestrial biospheres or civilizations teach  us? This book reviews the various scientific issues that arise in considering the question of how common extraterrestrial life is likely to be in our galaxy and whether humans are likely to detect it. The book stands out because of its very systematic organization and relatively unbiased treatment of the main open question. It covers all relevant aspects of many disciplines required to present the different   possible answers. It has and will provide undergraduates with a stimulating introduction to many of these fields at an early stage in their university careers, when they are still choosing a specialty. The difficulties and the range of possible answers to the title question are carefully addr...

  10. DCC-GARCH modeller med ulike avhengighetsstrukturer

    OpenAIRE

    Aardal, Helene

    2013-01-01

    Hovedfokuset i denne oppgaven er å finne gode metoder for modellering av volatilitet og avhengighetsstruktur i finansielle porteføljer. En spesifikk multivariat GARCH modell, Dynamic Conditional Correlation (DCC-) GARCH, kombineres med copulaer og par-copula-konstruksjoner for å få en mer fleksibel modell til å modellere nettopp dette. GARCH-modeller er verktøy for å predikere og analysere volatiliteten i tidsrekker når denne varierer over tid, mens copulaer gir mulighet til å modellere ...

  11. BayesDccGarch - An Implementation of Multivariate GARCH DCC Models

    OpenAIRE

    Fioruci, Jose A.; Ehlers, Ricardo S.; Louzada, Francisco

    2014-01-01

    Multivariate GARCH models are important tools to describe the dynamics of multivariate times series of financial returns. Nevertheless, these models have been much less used in practice due to the lack of reliable software. This paper describes the {\\tt R} package {\\bf BayesDccGarch} which was developed to implement recently proposed inference procedures to estimate and compare multivariate GARCH models allowing for asymmetric and heavy tailed distributions.

  12. Nonlinear GARCH model and 1 / f noise

    Science.gov (United States)

    Kononovicius, A.; Ruseckas, J.

    2015-06-01

    Auto-regressive conditionally heteroskedastic (ARCH) family models are still used, by practitioners in business and economic policy making, as a conditional volatility forecasting models. Furthermore ARCH models still are attracting an interest of the researchers. In this contribution we consider the well known GARCH(1,1) process and its nonlinear modifications, reminiscent of NGARCH model. We investigate the possibility to reproduce power law statistics, probability density function and power spectral density, using ARCH family models. For this purpose we derive stochastic differential equations from the GARCH processes in consideration. We find the obtained equations to be similar to a general class of stochastic differential equations known to reproduce power law statistics. We show that linear GARCH(1,1) process has power law distribution, but its power spectral density is Brownian noise-like. However, the nonlinear modifications exhibit both power law distribution and power spectral density of the 1 /fβ form, including 1 / f noise.

  13. Multivariate DCC-GARCH Model: -With Various Error Distributions

    OpenAIRE

    Orskaug, Elisabeth

    2009-01-01

    In this thesis we have studied the DCC-GARCH model with Gaussian, Student's $t$ and skew Student's t-distributed errors. For a basic understanding of the GARCH model, the univariate GARCH and multivariate GARCH models in general were discussed before the DCC-GARCH model was considered. The Maximum likelihood method is used to estimate the parameters. The estimation of the correctly specified likelihood is difficult, and hence the DCC-model was designed to allow for two stage estim...

  14. GARCH Option Valuation: Theory and Evidence

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Jacobs, Kris; Ornthanalai, Chayawat

    We survey the theory and empirical evidence on GARCH option valuation models. Our treatment includes the range of functional forms available for the volatility dynamic, multifactor models, nonnormal shock distributions as well as style of pricing kernels typically used. Various strategies...

  15. Ranking multivariate GARCH models by problem dimension

    NARCIS (Netherlands)

    M. Caporin (Massimiliano); M.J. McAleer (Michael)

    2010-01-01

    textabstractIn the last 15 years, several Multivariate GARCH (MGARCH) models have appeared in the literature. The two most widely known and used are the Scalar BEKK model of Engle and Kroner (1995) and Ding and Engle (2001), and the DCC model of Engle (2002). Some recent research has begun to examin

  16. NONLINEAR EXTENSION OF ASYMMETRIC GARCH MODEL WITHIN NEURAL NETWORK FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Josip Arnerić

    2016-05-01

    Full Text Available The importance of volatility for all market participants has led to the development and application of various econometric models. The most popular models in modelling volatility are GARCH type models because they can account excess kurtosis and asymmetric effects of financial time series. Since standard GARCH(1,1 model usually indicate high persistence in the conditional variance, the empirical researches turned to GJR-GARCH model and reveal its superiority in fitting the asymmetric heteroscedasticity in the data. In order to capture both asymmetry and nonlinearity in data, the goal of this paper is to develop a parsimonious NN model as an extension to GJR-GARCH model and to determine if GJR-GARCH-NN outperforms the GJR-GARCH model.

  17. MODELING ROMANIAN EXCHANGE RATE EVOLUTION WITH GARCH, TGARCH, GARCH- IN MEAN MODELS

    Directory of Open Access Journals (Sweden)

    Cociuba Mihail Ioan

    2011-07-01

    Full Text Available In this paper we analyze the return of exchange rate in order to test and analyze the best models which are capable of forecasting accurately there evolution. We apply the GARCH family models on the exchange rate return in order to obtain the best models for there volatility. Financial time series often exhibit abnormal characteristics, such as: serial correlation, non-stationarity, heteroskedasticity, asymmetric and are leptokurtic. Due to these characteristics autoregressive models such as autoregressive (AR, moving average (MA and autoregressive integrated moving-average (ARIMA are unable to capture the evolution of financial series, to represent the special characteristic of financial a hole new range of models where developed : generalized autoregressive conditional heteroskedasticity (GARCH, which are taking into account the heteroskedasticity of the errors term. The GARCH model allows for lags in the autoregressive term and in the variance term incorporates lags of the previous variance and also for the errors. The GARCH family has expanded in the last years in order to incorporate for asymmetry (Threshold GARCH, TGARCH and risk (GARCH -in Mean. We analyze the evolution of exchange rate for: Euro/RON, dollar/RON, yen/RON, British pound/RON, Swiss franc/RON for a period of five years from 2005 till 2011, we observe that in the analyzed period there are 2 sub-periods: 2005-2007 in which the RON appreciated constantly, and 2007-2011 in which the trend is depreciation for RON in respect to all the five currencies and the volatility was sensible higher than in the previous period. We obtain the returns on exchange rate by using the following transformation r=log(curs_t-log(curs_t-1; the five analyzed series display an leptokurtic and asymmetric behavioral. Using the GARCH, TGARCH and GARCH-in Mean models, we explicit the evolution of volatility throw this period, choosing the best model using the following : minimizing the value of the sum of

  18. Applications of GARCH models to energy commodities

    Science.gov (United States)

    Humphreys, H. Brett

    This thesis uses GARCH methods to examine different aspects of the energy markets. The first part of the thesis examines seasonality in the variance. This study modifies the standard univariate GARCH models to test for seasonal components in both the constant and the persistence in natural gas, heating oil and soybeans. These commodities exhibit seasonal price movements and, therefore, may exhibit seasonal variances. In addition, the heating oil model is tested for a structural change in variance during the Gulf War. The results indicate the presence of an annual seasonal component in the persistence for all commodities. Out-of-sample volatility forecasting for natural gas outperforms standard forecasts. The second part of this thesis uses a multivariate GARCH model to examine volatility spillovers within the crude oil forward curve and between the London and New York crude oil futures markets. Using these results the effect of spillovers on dynamic hedging is examined. In addition, this research examines cointegration within the oil markets using investable returns rather than fixed prices. The results indicate the presence of strong volatility spillovers between both markets, weak spillovers from the front of the forward curve to the rest of the curve, and cointegration between the long term oil price on the two markets. The spillover dynamic hedge models lead to a marginal benefit in terms of variance reduction, but a substantial decrease in the variability of the dynamic hedge; thereby decreasing the transactions costs associated with the hedge. The final portion of the thesis uses portfolio theory to demonstrate how the energy mix consumed in the United States could be chosen given a national goal to reduce the risks to the domestic macroeconomy of unanticipated energy price shocks. An efficient portfolio frontier of U.S. energy consumption is constructed using a covariance matrix estimated with GARCH models. The results indicate that while the electric

  19. "Ranking Multivariate GARCH Models by Problem Dimension"

    OpenAIRE

    Caporin, Massimiliano; McAleer, Michael

    2010-01-01

    textabstractIn the last 15 years, several Multivariate GARCH (MGARCH) models have appeared in the literature. The two most widely known and used are the Scalar BEKK model of Engle and Kroner (1995) and Ding and Engle (2001), and the DCC model of Engle (2002). Some recent research has begun to examine MGARCH specifications in terms of their out-of-sample forecasting performance. In this paper, we provide an empirical comparison of a set of MGARCH models, namely BEKK, DCC, Corrected DCC (cDCC) ...

  20. Option valuation with the simplified component GARCH model

    DEFF Research Database (Denmark)

    Dziubinski, Matt P.

    We introduce the Simplified Component GARCH (SC-GARCH) option pricing model, show and discuss sufficient conditions for non-negativity of the conditional variance, apply it to low-frequency and high-frequency financial data, and consider the option valuation, comparing the model performance...

  1. Method of moments estimation of GO-GARCH models

    NARCIS (Netherlands)

    Boswijk, H.P.; van der Weide, R.

    2009-01-01

    We propose a new estimation method for the factor loading matrix in generalized orthogonal GARCH (GO-GARCH) models. The method is based on the eigenvectors of a suitably defined sample autocorrelation matrix of squares and cross-products of the process. The method can therefore be easily applied to

  2. Forecasting Performance of Asymmetric GARCH Stock Market Volatility Models

    Directory of Open Access Journals (Sweden)

    Hojin Lee

    2009-12-01

    Full Text Available We investigate the asymmetry between positive and negative returns in their effect on conditional variance of the stock market index and incorporate the characteristics to form an out-of-sample volatility forecast. Contrary to prior evidence, however, the results in this paper suggest that no asymmetric GARCH model is superior to basic GARCH(1,1 model. It is our prior knowledge that, for equity returns, it is unlikely that positive and negative shocks have the same impact on the volatility. In order to reflect this intuition, we implement three diagnostic tests for volatility models: the Sign Bias Test, the Negative Size Bias Test, and the Positive Size Bias Test and the tests against the alternatives of QGARCH and GJR-GARCH. The asymmetry test results indicate that the sign and the size of the unexpected return shock do not influence current volatility differently which contradicts our presumption that there are asymmetric effects in the stock market volatility. This result is in line with various diagnostic tests which are designed to determine whether the GARCH(1,1 volatility estimates adequately represent the data. The diagnostic tests in section 2 indicate that the GARCH(1,1 model for weekly KOSPI returns is robust to the misspecification test. We also investigate two representative asymmetric GARCH models, QGARCH and GJR-GARCH model, for our out-of-sample forecasting performance. The out-of-sample forecasting ability test reveals that no single model is clearly outperforming. It is seen that the GJR-GARCH and QGARCH model give mixed results in forecasting ability on all four criteria across all forecast horizons considered. Also, the predictive accuracy test of Diebold and Mariano based on both absolute and squared prediction errors suggest that the forecasts from the linear and asymmetric GARCH models need not be significantly different from each other.

  3. Nonstationary ARCH and GARCH with t-distributed Innovations

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Søndergaard; Rahbek, Anders

    Consistency and asymptotic normality are established for the maximum likelihood estimators in the nonstationary ARCH and GARCH models with general t-distributed innovations. The results hold for joint estimation of (G)ARCH effects and the degrees of freedom parameter parametrizing the t-distribut......Consistency and asymptotic normality are established for the maximum likelihood estimators in the nonstationary ARCH and GARCH models with general t-distributed innovations. The results hold for joint estimation of (G)ARCH effects and the degrees of freedom parameter parametrizing the t......-distribution. With T denoting sample size, classic square-root T-convergence is shown to hold with closed form expressions for the multivariate covariances....

  4. DIAGNOSTIC TEST FOR GARCH MODELS BASED ON ABSOLUTE RESIDUAL AUTOCORRELATIONS

    Directory of Open Access Journals (Sweden)

    Farhat Iqbal

    2013-10-01

    Full Text Available In this paper the asymptotic distribution of the absolute residual autocorrelations from generalized autoregressive conditional heteroscedastic (GARCH models is derived. The correct asymptotic standard errors for the absolute residual autocorrelations are also obtained and based on these results, a diagnostic test for checking the adequacy of GARCH-type models are developed. Our results do not depend on the existence of higher moments and is therefore robust under heavy-tailed distributions.

  5. DIAGNOSTIC TEST FOR GARCH MODELS BASED ON ABSOLUTE RESIDUAL AUTOCORRELATIONS

    Directory of Open Access Journals (Sweden)

    Farhat Iqbal

    2013-10-01

    Full Text Available In this paper the asymptotic distribution of the absolute residual autocorrelations from generalized autoregressive conditional heteroscedastic (GARCH models is derived. The correct asymptotic standard errors for the absolute residual autocorrelations are also obtained and based on these results, a diagnostic test for checking the adequacy of GARCH-type models are developed. Our results do not depend on the existence of higher moments and is therefore robust under heavy-tailed distributions.

  6. A GARCH option pricing model with filtered historical simulation

    OpenAIRE

    Mancini, Loriano; Barone-Adesi, Giovanni; Engle, Robert

    2008-01-01

    We propose a new method for pricing options based on GARCH models with filtered historical innovaions. In an incomplete market framework, we allow for different distributions of historical and pricing return dynamics, which enhances the model’s flexibility to fit market option prices. An extensive empirical analysis based on S&P 500 Index options shows that our model outperforms other competing GARCH pricing models and ad hoc Black–Scholes models. We show that the flexible change of me...

  7. Astrophysics with Extraterrestrial Materials

    Science.gov (United States)

    Nittler, Larry R.; Ciesla, Fred

    2016-09-01

    Extraterrestrial materials, including meteorites, interplanetary dust, and spacecraft-returned asteroidal and cometary samples, provide a record of the starting materials and early evolution of the Solar System. We review how laboratory analyses of these materials provide unique information, complementary to astronomical observations, about a wide variety of stellar, interstellar and protoplanetary processes. Presolar stardust grains retain the isotopic compositions of their stellar sources, mainly asymptotic giant branch stars and Type II supernovae. They serve as direct probes of nucleosynthetic and dust formation processes in stars, galactic chemical evolution, and interstellar dust processing. Extinct radioactivities suggest that the Sun's birth environment was decoupled from average galactic nucleosynthesis for some tens to hundreds of Myr but was enriched in short-lived isotopes from massive stellar winds or explosions shortly before or during formation of the Solar System. Radiometric dating of meteorite components tells us about the timing and duration over which solar nebula solids were assembled into the building blocks of the planets. Components of the most primitive meteoritical materials provide further detailed constraints on the formation, processing, and transport of material and associated timescales in the Sun's protoplanetary disk as well as in other forming planetary systems.

  8. Extraterrestrial magnetic minerals

    Science.gov (United States)

    Pechersky, D. M.; Markov, G. P.; Tsel'movich, V. A.; Sharonova, Z. V.

    2012-07-01

    Thermomagnetic and microprobe analyses are carried out and a set of magnetic characteristics are measured for 25 meteorites and 3 tektites from the collections of the Vernadsky Geological Museum of the Russian Academy of Sciences and Museum of Natural History of the North-East Interdisciplinary Science Research Institute, Far Eastern Branch of the Russian Academy of Sciences. It is found that, notwithstanding their type, all the meteorites contain the same magnetic minerals and only differ by concentrations of these minerals. Kamacite with less than 10% nickel is the main magnetic mineral in the studied samples. Pure iron, taenite, and schreibersite are less frequent; nickel, various iron spinels, Fe-Al alloys, etc., are very rare. These minerals are normally absent in the crusts of the Earth and other planets. The studied meteorites are more likely parts of the cores and lower mantles of the meteoritic parent bodies (the planets). Uniformity in the magnetic properties of the meteorites and the types of their thermomagnetic (MT) curves is violated by secondary alterations of the meteorites in the terrestrial environment. The sediments demonstrate the same monotony as the meteorites: kamacite is likely the only extraterrestrial magnetic mineral, which is abundant in sediments and associated with cosmic dust. The compositional similarity of kamacite in iron meteorites and in cosmic dust is due to their common source; the degree of fragmentation of the material of the parent body is the only difference.

  9. Dependence between Croatian and European stock markets - A copula GARCH approach

    National Research Council Canada - National Science Library

    Silvo Dajcman

    2013-01-01

    ... (Austrian, French, German, Italian, and the U.K.'s). We propose a copula GARCH approach, where the return series are modeled as univariate GARCH processes and the dependence structure between the return series is defined by a copula function...

  10. Universalist ethics in extraterrestrial encounter

    Science.gov (United States)

    Baum, Seth D.

    2010-02-01

    If humanity encounters an extraterrestrial civilization, or if two extraterrestrial civilizations encounter each other, then the outcome may depend not only on the civilizations' relative strength to destroy each other but also on what ethics are held by one or both civilizations. This paper explores outcomes of encounter scenarios in which one or both civilizations hold a universalist ethical framework. Several outcomes are possible in such scenarios, ranging from one civilization destroying the other to both civilizations racing to be the first to commit suicide. Thus, attention to the ethics of both humanity and extraterrestrials is warranted in human planning for such an encounter. Additionally, the possibility of such an encounter raises profound questions for contemporary human ethics, even if such an encounter never occurs.

  11. Do fat tails matter in GARCH estimation: testing market efficiency in two transition economies

    OpenAIRE

    Harrison, B.; Paton, D

    2007-01-01

    The use of the GARCH-class of models is commonplace when examining stock market returns. In this paper we use data on stock markets in two transition economies, the Czech Republic and Romania, to demonstrate the importance of using the correct GARCH specification. When residuals are characterised by fat tails or kurtosis, the use of a GARCH-t specification is appropriate. Diagnostic tests suggest that the GARCH-t specification is appropriate for modelling stock market returns in Romania, whil...

  12. Generalized Dynamic Factor Model + GARCH Exploiting Multivariate Information for Univariate Prediction

    OpenAIRE

    Alessi, Lucia; Barigozzi, Matteo; Capasso, Marco

    2006-01-01

    We propose a new model for multivariate forecasting which combines the Generalized Dynamic Factor Model (GDFM)and the GARCH model. The GDFM, applied to a huge number of series, captures the multivariate information and disentangles the common and the idiosyncratic part of each series of returns. In this financial analysis, both these components are modeled as a GARCH. We compare GDFM+GARCH and standard GARCH performance on samples up to 475 series, predicting both levels and volatility of ret...

  13. The Extraterrestrial Life Debate from Antiquity to 1900

    Science.gov (United States)

    Crowe, Michael J.; Dowd, Matthew F.

    This chapter provides an overview of the Western historical debate regarding extraterrestrial life from antiquity to the beginning of the twentieth century. Though schools of thought in antiquity differed on whether extraterrestrial life existed, by the Middle Ages, the Aristotelian worldview of a unified, finite cosmos without extraterrestrials was most influential, though there were such dissenters as Nicholas of Cusa. That would change as the Copernican revolution progressed. Scholars such as Bruno, Kepler, Galileo, and Descartes would argue for a Copernican system of a moving Earth. Cartesian and Newtonian physics would eventually lead to a view of the universe in which the Earth was one of many planets in one of many solar systems extended in space. As this cosmological model was developing, so too were notions of extraterrestrial life. Popular and scientific writings, such as those by Fontenelle and Huygens, led to a reversal of fortunes for extraterrestrials, who by the end of the century were gaining recognition. From 1700 to 1800, many leading thinkers discussed extraterrestrial intelligent beings. In doing so, they relied heavily on arguments from analogy and such broad principles and ideas as the Copernican Principle, the Principle of Plenitude, and the Great Chain of Being. Physical evidence for the existence of extraterrestrials was minimal, and was always indirect, such as the sighting of polar caps on Mars, suggesting similarities between Earth and other places in the universe. Nonetheless, the eighteenth century saw writers from a wide variety of genres—science, philosophy, theology, literature—speculate widely on extraterrestrials. In the latter half of the century, increasing research in stellar astronomy would be carried out, heavily overlapping with an interest in extraterrestrial life. By the end of the eighteenth century, belief in intelligent beings on solar system planets was nearly universal and certainly more common than it would be by

  14. Christian Soteriology and Extraterrestrial Intelligence

    Science.gov (United States)

    Weidemann, C.

    The paper presents an argument for the incompatibility of classical Christian soteriology (doctrine of salvation) with belief in numerous extraterrestrial intelligent life forms (ETI). Four popular answers to the problem are discussed and rejected: a) unlike humanity, extraterrestrial intelligent species are not in need of salvation; b) Jesus of Nazareth has reconciled the entire cosmos to God; c) God or the second person of the Trinity has incarnated (or will incarnate) himself multiple times; d) alien sinners have been or are going to be saved by means different from a divine incarnation. The final section deals with remaining options for rational Christian believers and speculates briefly about consequences for interstellar space flight.

  15. The search for extraterrestrial intelligence.

    Science.gov (United States)

    Wilson, T L

    2001-02-22

    As far as we know, humanity is alone in the Universe: there is no definite evidence for the existence of extraterrestrial life, let alone extraterrestrial civilizations (ETCs) capable of communicating or travelling over interstellar distances. Yet popular speculation about the existence of ETCs abounds, including reports of alien visitations either now or in the past. But there is a middle way. It is now possible to put limits on the existence of ETCs of varying capabilities, within arbitrary distances from the Solar System, and conceive of real-world strategies whereby we might communicate with ETCs, or they with us.

  16. Evaluating multivariate GARCH models in the Nordic electricity markets

    Energy Technology Data Exchange (ETDEWEB)

    Malo, P.; Kanto, A.

    2005-07-01

    This paper considers a variety of specification tests for multivariate GARCH models that are used in dynamic hedging in the electricity markets. The test statistics include the robust conditional moments tests for sign-size bias along with the recently introduced copula tests for an appropriate dependence structure. We consider this effort worthwhile, since quite often the tests of multivariate GARCH models are easily omitted and the models become selected ad-hoc depending on the results they generate. Hedging performance comparisons, in terms of unconditional and conditional ex-post variance portfolio reduction, are conducted. (orig.)

  17. The Search for Extraterrestrial Intelligence.

    Science.gov (United States)

    Jones, Barrie W.

    2003-01-01

    Traces the efforts of Searching for Extraterrestrial Technological Intelligence (SETI) since 1960 when a radio-telescope was used to see if any messages were being sent from the vicinity of two nearby stars. Describes attempts to detect microwave/optical signals and technological modification of the cosmic environment. (Author/KHR)

  18. Outlier detection in the GARCH (1,1) model

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); D.J.C. van Dijk (Dick)

    1999-01-01

    textabstractIn this paper the issue of detecting and handling outliers in the GARCH(1,1) model is addressed. Simulation evidence shows that neglecting even a single outlier has a dramatic on parameter estimates. To detect and correct for outliers, we propose an adaptation of the iterative in Chen an

  19. Crude Oil Hedging Strategies Using Dynamic Multivariate GARCH

    NARCIS (Netherlands)

    R. Tansuchat (Roengchai); C-L. Chang (Chia-Lin); M.J. McAleer (Michael)

    2010-01-01

    textabstractThe paper examines the performance of four multivariate volatility models, namely CCC, VARMA-GARCH, DCC and BEKK, for the crude oil spot and futures returns of two major benchmark international crude oil markets, Brent and WTI, to calculate optimal portfolio weights and optimal hedge

  20. Crude Oil Hedging Strategies Using Dynamic Multivariate GARCH

    NARCIS (Netherlands)

    R. Tansuchat (Roengchai); C-L. Chang (Chia-Lin); M.J. McAleer (Michael)

    2010-01-01

    textabstractThe paper examines the performance of four multivariate volatility models, namely CCC, VARMA-GARCH, DCC and BEKK, for the crude oil spot and futures returns of two major benchmark international crude oil markets, Brent and WTI, to calculate optimal portfolio weights and optimal hedge rat

  1. Robust Ranking of Multivariate GARCH Models by Problem Dimension

    NARCIS (Netherlands)

    M. Caporin (Massimiliano); M.J. McAleer (Michael)

    2012-01-01

    textabstractDuring the last 15 years, several Multivariate GARCH (MGARCH) models have appeared in the literature. Recent research has begun to examine MGARCH specifications in terms of their out-of-sample forecasting performance. We provide an empirical comparison of alternative MGARCH models, namel

  2. Ranking Multivariate GARCH Models by Problem Dimension: An Empirical Evaluation

    NARCIS (Netherlands)

    M. Caporin (Massimiliano); M.J. McAleer (Michael)

    2011-01-01

    textabstractIn the last 15 years, several Multivariate GARCH (MGARCH) models have appeared in the literature. Recent research has begun to examine MGARCH specifications in terms of their out-of-sample forecasting performance. In this paper, we provide an empirical comparison of a set of models, name

  3. Liberty and the Limits to the Extraterrestrial State

    Science.gov (United States)

    Cockell, C. S.

    The physical conditions that inhere in extraterrestrial environments have a tendency to drive society toward collectivist mechanisms of political and economic order to successfully cope with, and prevent possible disaster caused by, the lethal external conditions. Liberty will therefore be eroded by deliberate human action, through extraterrestrial authorities, and through a natural restriction in concepts of liberty that will attend the development and behaviour of people in confined environments. The emergence of extraterrestrial governance that nurtures liberty in outer space will require the formation of many institutions that encourage competition and reduce political and economic monopolies - with the legal system to sustain them. This problem is most clearly manifest in oxygen production. These considerations allow the purpose and limits of the extraterrestrial state and precursor forms of governance to be circumscribed. Far from being a purely speculative enquiry, this discussion allows requirements in physical architecture and social organisation to be identified that can be considered from the earliest stages of space exploration and settlement.

  4. Markov-switching GARCH models in finance: a unifying framework with an application to the German stock market

    OpenAIRE

    Gerrit Reher; Bernd Wilfling

    2011-01-01

    In this paper we develop a unifying Markov-switching GARCH model which enables us (1) to specify complex GARCH equations in two distinct Markov-regimes, and (2) to model GARCH equations of different functional forms across the two Markov-regimes. To give a simple example, our flexible Markov-switching approach is capable of estimating an exponential GARCH (EGARCH) specification in the first and a standard GARCH specification in the second Markov-regime. We derive a maximum likelihood estimati...

  5. ESO Archive Operations in support of Services in Garching

    Science.gov (United States)

    Fourniol, Nathalie

    2015-12-01

    ESO Science Archive Facility (SAF) is the unique access point to the La Silla Paranal Observatory (LPO) raw data. It also services data products created at ESO with state-of-the-art pipelines, or fed back by the external astronomical community. ESO SAF is a big success in the sense that users access the data every single day, and they want their data fast! A copy of the ALMA Science Archive (ASA) is also accessible at Garching to the European ALMA community via the European ALMA Regional Center. A data portal allows users to get access to the data. In this poster we present the Archive Operations in support of services in Garching, from archiving the data to making them available to the community.

  6. Semiparametric Inference in a GARCH-in-Mean Model

    DEFF Research Database (Denmark)

    Christensen, Bent Jesper; Dahl, Christian Møller; Iglesias, Emma M.

    , such as the dividend yield. Using the profile likelihood approach, we show that our estimator under stated conditions is consistent, asymp- totically normal, and efficient, i.e. it achieves the semiparametric lower bound. A sampling experiment provides evidence on finite sample properties as well as comparisons......A new semiparametric estimator for an empirical asset pricing model with general nonpara- metric risk-return tradeoff and a GARCH process for the underlying volatility is introduced. The estimator does not rely on any initial parametric estimator of the conditional mean func- tion, and this feature...... facilitates the derivation of asymptotic theory under possible nonlinearity of unspecified form of the risk-return tradeoff. Besides the nonlinear GARCH-in-mean effect, our specification accommodates exogenous regressors that are typically used as conditioning variables entering linearly in the mean equation...

  7. Modelos ARCH, GARCH y EGARCH: aplicaciones a series financieras

    Directory of Open Access Journals (Sweden)

    Cepeda Cuervo Edilberto

    2008-08-01

    Full Text Available En este artículo se incluye una descripción de los modelos
    ARCH, GARCH y EGARCH, y de los procesos de estimación de sus
    parámetros usando máxima verosimilitud. Se propone un modelo
    alternativo para el análisis de series financieras y se estudian
    las series de precios y de retornos de las acciones de
    Gillette. La selección de modelos usando los criterios AIC y
    BIC permite concluir que, de los modelos considerados el
    GARCH(1,2 es el que mejor explica el comportamiento de los
    precios de las acciones y el EGARCH(2,1 es el que mejor
    explica la serie de los retornos.

  8. The moral status of extraterrestrial life.

    Science.gov (United States)

    Persson, Erik

    2012-10-01

    If we eventually discover extraterrestrial life, do we have any moral obligations for how to treat the life-forms we find; does it matter whether they are intelligent, sentient, or just microbial-and does it matter that they are extraterrestrial? In this paper, I examine these questions by looking at two of the basic questions in moral philosophy: What does it take to be a moral object? and What has value of what kind? I will start with the first of these questions by looking at the most important attempts to answer this question on our own planet and by asking whether and how they could be applied to extraterrestrial life. The results range from a very strong protection of all extraterrestrial life and all extraterrestrial environments, whether inhabited or not, to total exclusion of extraterrestrial life. Subsequently, I also examine whether extraterrestrial life that lacks moral status can have value to human or alien life with moral status, and if that could generate any obligations for how to treat extraterrestrial life. Based on this analysis, I conclude that extraterrestrial life-forms can have both instrumental value and end value to moral objects, which has strong implications for how to treat them.

  9. Real time detection of structural breaks in GARCH models

    OpenAIRE

    He, Zhongfang; Maheu, John M.

    2009-01-01

    This paper proposes a sequential Monte Carlo method for estimating GARCH models subject to an unknown number of structural breaks. We use particle filtering techniques that allow for fast and efficient updates of posterior quantities and forecasts in real-time. The method conveniently deals with the path dependence problem that arises in these type of models. The performance of the method is shown to work well using simulated data. Applied to daily NASDAQ returns, the evidence favors a partia...

  10. A GARCH analysis of dark-pool trades

    OpenAIRE

    De Peretti, Philippe; Tapiero, Oren

    2014-01-01

    The ability to trade in dark-pools without publicly announcing trading orders, concerns regulators and market participants alike. This paper analyzes the information contribution of dark trades to the intraday volatility process. The analysis is conducted by performing a GARCH estimation framework where errors follow the generalized error distribution (GED) and two different proxies for dark trading activity are separately included in the volatility equation. Results indicate that dark trades...

  11. Robust Ranking of Multivariate GARCH Models by Problem Dimension

    OpenAIRE

    McAleer, Michael; Caporin, Massimiliano

    2012-01-01

    textabstractDuring the last 15 years, several Multivariate GARCH (MGARCH) models have appeared in the literature. Recent research has begun to examine MGARCH specifications in terms of their out-of-sample forecasting performance. We provide an empirical comparison of alternative MGARCH models, namely BEKK, DCC, Corrected DCC (cDCC), CCC, OGARCH Exponentially Weighted Moving Average, and covariance shrinking, using historical data for 89 US equities. We contribute to the literature in several ...

  12. Testing for Causality in Variance Usinf Multivariate GARCH Models

    OpenAIRE

    Christian M. Hafner; Herwartz, Helmut

    2008-01-01

    Tests of causality in variance in multiple time series have been proposed recently, based on residuals of estimated univariate models. Although such tests are applied frequently, little is known about their power properties. In this paper we show that a convenient alternative to residual based testing is to specify a multivariate volatility model, such as multivariate GARCH (or BEKK), and construct a Wald test on noncausality in variance. We compare both approaches to testing causality in var...

  13. Testing for causality in variance using multivariate GARCH models

    OpenAIRE

    Hafner, Christian; Herwartz, H.

    2004-01-01

    textabstractTests of causality in variance in multiple time series have been proposed recently, based on residuals of estimated univariate models. Although such tests are applied frequently little is known about their power properties. In this paper we show that a convenient alternative to residual based testing is to specify a multivariate volatility model, such as multivariate GARCH (or BEKK), and construct a Wald test on noncausality in variance. We compare both approaches to testing causa...

  14. Forecasting Tehran stock exchange volatility; Markov switching GARCH approach

    Science.gov (United States)

    Abounoori, Esmaiel; Elmi, Zahra (Mila); Nademi, Younes

    2016-03-01

    This paper evaluates several GARCH models regarding their ability to forecast volatility in Tehran Stock Exchange (TSE). These include GARCH models with both Gaussian and fat-tailed residual conditional distribution, concerning their ability to describe and forecast volatility from 1-day to 22-day horizon. Results indicate that AR(2)-MRSGARCH-GED model outperforms other models at one-day horizon. Also, the AR(2)-MRSGARCH-GED as well as AR(2)-MRSGARCH-t models outperform other models at 5-day horizon. In 10 day horizon, three models of AR(2)-MRSGARCH outperform other models. Concerning 22 day forecast horizon, results indicate no differences between MRSGARCH models with that of standard GARCH models. Regarding Risk management out-of-sample evaluation (95% VaR), a few models seem to provide reasonable and accurate VaR estimates at 1-day horizon, with a coverage rate close to the nominal level. According to the risk management loss functions, there is not a uniformly most accurate model.

  15. Volatility forecasting with the wavelet transformation algorithm GARCH model: Evidence from African stock markets

    Directory of Open Access Journals (Sweden)

    Mohd Tahir Ismail

    2016-06-01

    Full Text Available The daily returns of four African countries' stock market indices for the period January 2, 2000, to December 31, 2014, were employed to compare the GARCH(1,1 model and a newly proposed Maximal Overlap Discreet Wavelet Transform (MODWT-GARCH(1,1 model. The results showed that although both models fit the returns data well, the forecast produced by the GARCH(1,1 model underestimates the observed returns whereas the newly proposed MODWT-GARCH(1,1 model generates an accurate forecast value of the observed returns. The results generally showed that the newly proposed MODWT-GARCH(1,1 model best fits returns series for these African countries. Hence the proposed MODWT-GARCH should be applied on other context to further verify its validity.

  16. Hegel, Analogy, and Extraterrestrial Life

    Science.gov (United States)

    Ross, Joseph T.

    Georg Wilhelm Friedrich Hegel rejected the possibility of life outside of the Earth, according to several scholars of extraterrestrial life. Their position is that the solar system and specifically the planet Earth is the unique place in the cosmos where life, intelligence, and rationality can be. The present study offers a very different interpretation of Hegel's statements about the place of life on Earth by suggesting that, although Hegel did not believe that there were other solar systems where rationality is present, he did in fact suggest that planets in general, not the Earth exclusively, have life and possibly also intelligent inhabitants. Analogical syllogisms are superficial, according to Hegel, insofar as they try to conclude that there is life on the Moon even though there is no evidence of water or air on that body. Similar analogical arguments for life on the Sun made by Johann Elert Bode and William Herschel were considered by Hegel to be equally superficial. Analogical arguments were also used by astronomers and philosophers to suggest that life could be found on other planets in our solar system. Hegel offers no critique of analogical arguments for life on other planets, and in fact Hegel believed that life would be found on other planets. Planets, after all, have meteorological processes and therefore are "living" according to his philosophical account, unlike the Moon, Sun, and comets. Whereas William Herschel was already finding great similarities between the Sun and the stars and had extended these similarities to the property of having planets or being themselves inhabitable worlds, Hegel rejected this analogy. The Sun and stars have some properties in common, but for Hegel one cannot conclude from these similarities to the necessity that stars have planets. Hegel's arguments against the presence of life in the solar system were not directed against other planets, but rather against the Sun and Moon, both of which he said have a different

  17. Galactic extraterrestrial intelligence. I - The constraint on search strategies imposed by the possibility of interstellar travel

    Science.gov (United States)

    Singer, C. E.

    1982-03-01

    The possibility that extraterrestrial intelligence might settle the Galaxy by interstellar travel is investigated. The existence of this possibility is shown to be incompatible with the existence of a large number of potential sources of communication from extraterrestrial intelligences in the Galaxy. A detailed examination of suggested resolutions of this contradiction is presented. These include physical, temporal and sociological explanations. The sociological explanations include the so-called disinterest, self-destruction, fizzle, ZPG, taboo, and private zoo hypotheses. Each of these is carefully shown to require incredible universal ad hoc assumptions about the nature of extraterrestrial intelligence. It is concluded that proposed serial search modes for communication from extraterrestrial intelligence have negligible chance of success. A mathematical formalism for evaluating other search modes is also developed.

  18. Inflation-Theory Implications for Extraterrestrial Visitation

    Science.gov (United States)

    Deardoff, J.; Haisch, B.; Maccabee, B.; Puthoff, H. E.

    It has recently been argued that anthropic reasoning applied to inflation theory reinforces the prediction that we should find ourselves part of a large, galaxy-sized civilisation, thus strengthening Fermi's paradox concerning `Where are they?' Furthermore, superstring and M-brane theory allow for the possibility of parallel universes, some of which in principle could be habitable. In addition, discussion of such exotic transport concepts as `traversable wormholes' now appears in the rigorous physics literature. As a result, the `We are alone' solution to Fermi's paradox, based on the constraints of earlier 20th century viewpoints, appears today to be inconsistent with new developments in our best current physics and astrophysics theories. Therefore we reexamine and reevaluate the present assumption that extraterrestrials or their probes are not in the vicinity of Earth, and argue instead that some evidence of their presence might be found in certain high-quality UFO reports. This study follows up on previous arguments that (1) interstellar travel for advanced civilizations is not a priori ruled out by physical principles and therefore may be practicable, and (2) such advanced civilisations may value the search for knowledge from uncontaminated species more than direct, interspecies communication, thereby accounting for apparent covertness regarding their presence.

  19. The Problem of Extraterrestrial Civilizations and Extrasolar Planets

    Science.gov (United States)

    Mickaelian, A. M.

    2015-07-01

    The problem of extraterrestrial intelligence is the best example of multidisciplinary science. Here philosophy and religion, astronomy, radiophysics, spectrography, space flights and astronautics, geology and planetology, astroecology, chemistry and biology, history and archaeology, psychology, sociology, linguistics, diplomacy, UFOs and peculiar phenomena are involved. Among these many-sided studies, astronomers have probably displayed the most progress by discovering thousands of extrasolar planets. At present, a number of search programs are being accomplished, including those with space telescopes, and planets in so-called "habitable zone" are considered as most important ones, for which various orbital and physical parameters are being calculated. As the discovery of extraterrestrial life is the final goal, a special attention is given to Earth-like planets, for the discovery of which most sensitive technical means are necessary.

  20. GARCH modelling of covariance in dynamical estimation of inverse solutions

    Energy Technology Data Exchange (ETDEWEB)

    Galka, Andreas [Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel (Germany) and Institute of Statistical Mathematics (ISM), Minami-Azabu 4-6-7, Tokyo 106-8569 (Japan)]. E-mail: galka@physik.uni-kiel.de; Yamashita, Okito [ATR Computational Neuroscience Laboratories, Hikaridai 2-2-2, Kyoto 619-0288 (Japan); Ozaki, Tohru [Institute of Statistical Mathematics (ISM), Minami-Azabu 4-6-7, Tokyo 106-8569 (Japan)

    2004-12-06

    The problem of estimating unobserved states of spatially extended dynamical systems poses an inverse problem, which can be solved approximately by a recently developed variant of Kalman filtering; in order to provide the model of the dynamics with more flexibility with respect to space and time, we suggest to combine the concept of GARCH modelling of covariance, well known in econometrics, with Kalman filtering. We formulate this algorithm for spatiotemporal systems governed by stochastic diffusion equations and demonstrate its feasibility by presenting a numerical simulation designed to imitate the situation of the generation of electroencephalographic recordings by the human cortex.

  1. Hedging emerging market stock prices with oil, gold, VIX, and bonds: A comparison between DCC, ADCC and GO-GARCH

    OpenAIRE

    Syed Abul, Basher; Perry, Sadorsky

    2015-01-01

    While much research uses multivariate GARCH to model volatility dynamics and risk measures, one particular type of multivariate GARCH model, GO-GARCH, has been underutilized. This paper uses DCC, ADCC and GO-GARCH to model volatilities and conditional correlations between emerging market stock prices, oil prices, VIX, gold prices and bond prices. A rolling window analysis is used to construct out-of-sample onestep-ahead forecasts of dynamic conditional correlations and optimal hedge rat...

  2. Modeling Markov switching ARMA-GARCH neural networks models and an application to forecasting stock returns.

    Science.gov (United States)

    Bildirici, Melike; Ersin, Özgür

    2014-01-01

    The study has two aims. The first aim is to propose a family of nonlinear GARCH models that incorporate fractional integration and asymmetric power properties to MS-GARCH processes. The second purpose of the study is to augment the MS-GARCH type models with artificial neural networks to benefit from the universal approximation properties to achieve improved forecasting accuracy. Therefore, the proposed Markov-switching MS-ARMA-FIGARCH, APGARCH, and FIAPGARCH processes are further augmented with MLP, Recurrent NN, and Hybrid NN type neural networks. The MS-ARMA-GARCH family and MS-ARMA-GARCH-NN family are utilized for modeling the daily stock returns in an emerging market, the Istanbul Stock Index (ISE100). Forecast accuracy is evaluated in terms of MAE, MSE, and RMSE error criteria and Diebold-Mariano equal forecast accuracy tests. The results suggest that the fractionally integrated and asymmetric power counterparts of Gray's MS-GARCH model provided promising results, while the best results are obtained for their neural network based counterparts. Further, among the models analyzed, the models based on the Hybrid-MLP and Recurrent-NN, the MS-ARMA-FIAPGARCH-HybridMLP, and MS-ARMA-FIAPGARCH-RNN provided the best forecast performances over the baseline single regime GARCH models and further, over the Gray's MS-GARCH model. Therefore, the models are promising for various economic applications.

  3. Modeling Markov Switching ARMA-GARCH Neural Networks Models and an Application to Forecasting Stock Returns

    Directory of Open Access Journals (Sweden)

    Melike Bildirici

    2014-01-01

    Full Text Available The study has two aims. The first aim is to propose a family of nonlinear GARCH models that incorporate fractional integration and asymmetric power properties to MS-GARCH processes. The second purpose of the study is to augment the MS-GARCH type models with artificial neural networks to benefit from the universal approximation properties to achieve improved forecasting accuracy. Therefore, the proposed Markov-switching MS-ARMA-FIGARCH, APGARCH, and FIAPGARCH processes are further augmented with MLP, Recurrent NN, and Hybrid NN type neural networks. The MS-ARMA-GARCH family and MS-ARMA-GARCH-NN family are utilized for modeling the daily stock returns in an emerging market, the Istanbul Stock Index (ISE100. Forecast accuracy is evaluated in terms of MAE, MSE, and RMSE error criteria and Diebold-Mariano equal forecast accuracy tests. The results suggest that the fractionally integrated and asymmetric power counterparts of Gray’s MS-GARCH model provided promising results, while the best results are obtained for their neural network based counterparts. Further, among the models analyzed, the models based on the Hybrid-MLP and Recurrent-NN, the MS-ARMA-FIAPGARCH-HybridMLP, and MS-ARMA-FIAPGARCH-RNN provided the best forecast performances over the baseline single regime GARCH models and further, over the Gray’s MS-GARCH model. Therefore, the models are promising for various economic applications.

  4. Tail behavior and OLS based robust inference in AR-GARCH models

    DEFF Research Database (Denmark)

    Lange, T

    2011-01-01

    The scope of this paper is twofold. We first describe the tail behavior for general AR-GARCH processes and hence extend the results of Basrak, Davis, and Mikosch (2002b) to another empirical relevant model class. Second, and primarily, we study properties for the OLS estimator in general AR-GARCH...

  5. Limit theory for the sample autocorrelations and extremes of a GARCH (1,1) process

    NARCIS (Netherlands)

    Mikosch, T; Starica, C

    2000-01-01

    The asymptotic theory for the sample autocorrelations and extremes of a GARCH(I, 1) process is provided. Special attention is given to the case when the sum of the ARCH and GARCH parameters is close to 1, that is, when one is close to an infinite Variance marginal distribution. This situation has be

  6. A Lagrange Multiplier Test for Testing the Adequacy of the Constant Conditional Correlation GARCH Model

    DEFF Research Database (Denmark)

    Catani, Paul; Teräsvirta, Timo; Yin, Meiqun

    A Lagrange multiplier test for testing the parametric structure of a constant conditional correlation generalized autoregressive conditional heteroskedasticity (CCC-GARCH) model is proposed. The test is based on decomposing the CCC-GARCH model multiplicatively into two components, one of which...

  7. GARCH-GED Model Based-AGA for Financial Risk Measure

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiu-fang

    2013-01-01

    GARCH model under the assumption of generalized error distribution (GED) is used to obtain the daily-volatility of log-return. The parameters are estimated by adaptive genetic algorithm. The tests of VaR and CVaR show that GARCH-GED model is valid for financial risk measure.

  8. A Hybrid Fuzzy GJR-GARCH Modeling Approach for Stock Market Volatility Forecasting

    Directory of Open Access Journals (Sweden)

    Leandro Maciel

    2012-09-01

    Full Text Available Forecasting stock market returns volatility is a challenging task that has attracted the attention of market practitioners, regulators and academics in recent years. This paper proposes a Fuzzy GJR-GARCH model to forecast the volatility of S&P 500 and Ibovespa indexes. The model comprises both the concept of fuzzy inference systems and GJR-GARCH modeling approach in order to consider the principles of time-varying volatility, leverage effects and volatility clustering, in which changes are cataloged by similarity. Moreover, a differential evolution (DE algorithm is suggested to solve the problem of Fuzzy GJR-GARCH parameters estimation. The results indicate that the proposed method offers significant improvements in volatility forecasting performance in comparison with GARCH-type models and with a current Fuzzy-GARCH model reported in the literature. Furthermore, the DE-based algorithm aims to achieve an optimal solution with a rapid convergence rate.

  9. Modelling Multivariate Autoregressive Conditional Heteroskedasticity with the Double Smooth Transition Conditional Correlation GARCH Model

    DEFF Research Database (Denmark)

    Silvennoinen, Annastiina; Teräsvirta, Timo

    In this paper we propose a multivariate GARCH model with a time-varying conditional correlation structure. The new Double Smooth Transition Conditional Correlation GARCH model extends the Smooth Transition Conditional Correlation GARCH model of Silvennoinen and Ter¨asvirta (2005) by including...... another variable according to which the correlations change smoothly between states of constant correlations. A Lagrange multiplier test is derived to test the constancy of correlations against the DSTCC-GARCH model, and another one to test for another transition in the STCC-GARCH framework. In addition......, other specification tests, with the aim of aiding the model building procedure, are considered. Analytical expressions for the test statistics and the required derivatives are provided. The model is applied to a selection of world stock indices, and it is found that time is an important factor affecting...

  10. GARCH-EVT模型在动态VaR中的应用%Application of GARCH-EVT Model in Dynamic VaR

    Institute of Scientific and Technical Information of China (English)

    高莹; 周鑫; 金秀

    2008-01-01

    在综合考虑金融资产收益数据分布的波动集群性和厚尾特征,尤其是波动的条件异方差对动态VaR估计的影响的基础上,运用极值理论(EVT),建立了GARCH-EVT模型,计算了上海证券市场综合指数的动态VaR,并且将GARCH-EVT模型与GARCH-NORMAL模型进行比较.通过实证分析,并利用后验测试,结果表明GARCH-EVT模型优于GARCH-NORMAL模型.GARCH-EVT模型很好地解决了波动集群性和厚尾现象,为管理者和投资者提供了一个控制风险、预测收益的量化工具.

  11. Unidentified flying objects and extraterrestrial life

    Science.gov (United States)

    Marsh, Carole

    Discusses efforts to find intelligent life on other planets and theories on this topic and describes UFO sightings and other phenomena that are given as evidence of extraterrestrial visitors among us.

  12. The Search for Extraterrestrials Intercepting Alien Signals

    CERN Document Server

    Ross, Monte

    2009-01-01

    In The Search for Extraterrestrials, Monte Ross explores in detail the key problems in starting a search, the programs that have failed and those that continue. He includes the fundamental considerations and the physics of the necessary laser, UV, IR and RF technologies, as well as coding and information theory considerations. The author explores future possibilities providing the reader with a comprehensive view of the many ways signals from aliens could be sent and explains why the search using RF leaves more than 99% of the electromagnetic spectrum unexamined. He also demonstrates the many parts of the electromagnetic spectrum, considering the next likely steps in this unique enterprise. Given man’s intrinsic nature to explore, the search will continue in one form or many, until success is achieved, which may be tomorrow or a millennium away. In summary, Monte Ross proposes to get around the failure of a fruitless search at radio frequencies by developing, in a precise way, the argument for searching for...

  13. Raman imaging of extraterrestrial materials

    Science.gov (United States)

    Wang, Alian; Korotev, Randy L.; Jolliff, Bradley L.; Ling, Zongcheng

    2015-07-01

    Laser Raman Spectroscopy has been proposed and is under extensive development for surface exploration missions to planetary bodies of our Solar System. It reveals information on molecular structure and chemistry. The spatial distribution of molecular species in natural geological samples and planetary materials has significance for the geological processes by which they formed. Raman imaging is the best way to combine the molecular identification and characterization of geologic materials with their spatial distribution. This paper reports Raman imaging studies of five types of extraterrestrial materials and three terrestrial samples using a state-of-the-art Raman imaging system. The Raman spectral features of major, minor, and trace species in these samples, together with their spatial correlations revealed by these Raman imaging studies indicate the genetic relationships and the geological processes that these materials have been experienced. For robotic planetary surface exploration mission, a simple yet very useful molecular map of a sample can be generated by using line-scan or grid-scan of an in situ Raman system with tightly focused laser beam.

  14. Realized GARCH: A Complete Model of Returns and Realized Measures of Volatility

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Huang, Zhuo (Albert); Shek, Howard Howan

    of the classical GARCH framework; it implies an ARMA structure for the conditional variance and realized measures of volatility; and models in this class are parsimonious and simple to estimate. A key feature of the Realized GARCH framework is a measurement equation that relates the observed realized measure...... to latent volatility. This equation facilitates a simple modeling of the dependence between returns and future volatility that is commonly referred to as the leverage effect. An empirical application with DJIA stocks and an exchange traded index fund shows that a simple Realized GARCH structure leads...

  15. Modelling world gold prices and USD foreign exchange relationship using multivariate GARCH model

    Science.gov (United States)

    Ping, Pung Yean; Ahmad, Maizah Hura Binti

    2014-12-01

    World gold price is a popular investment commodity. The series have often been modeled using univariate models. The objective of this paper is to show that there is a co-movement between gold price and USD foreign exchange rate. Using the effect of the USD foreign exchange rate on the gold price, a model that can be used to forecast future gold prices is developed. For this purpose, the current paper proposes a multivariate GARCH (Bivariate GARCH) model. Using daily prices of both series from 01.01.2000 to 05.05.2014, a causal relation between the two series understudied are found and a bivariate GARCH model is produced.

  16. Structure and asymptotic theory for nonlinear models with GARCH errors

    Directory of Open Access Journals (Sweden)

    Felix Chan

    2015-01-01

    Full Text Available Nonlinear time series models, especially those with regime-switching and/or conditionally heteroskedastic errors, have become increasingly popular in the economics and finance literature. However, much of the research has concentrated on the empirical applications of various models, with little theoretical or statistical analysis associated with the structure of the processes or the associated asymptotic theory. In this paper, we derive sufficient conditions for strict stationarity and ergodicity of three different specifications of the first-order smooth transition autoregressions with heteroskedastic errors. This is essential, among other reasons, to establish the conditions under which the traditional LM linearity tests based on Taylor expansions are valid. We also provide sufficient conditions for consistency and asymptotic normality of the Quasi-Maximum Likelihood Estimator for a general nonlinear conditional mean model with first-order GARCH errors.

  17. Modeling the Volatility of Exchange Rates: GARCH Models

    Directory of Open Access Journals (Sweden)

    Fahima Charef

    2017-03-01

    Full Text Available The modeling of the dynamics of the exchange rate at a long time remains a financial and economic research center. In our research we tried to study the relationship between the evolution of exchange rates and macroeconomic fundamentals. Our empirical study is based on a series of exchange rates for the Tunisian dinar against three currencies of major trading partners (dollar, euro, yen and fundamentals (the terms of trade, the inflation rate, the interest rate differential, of monthly data, from jan 2000 to dec-2014, for the case of the Tunisia. We have adopted models of conditional heteroscedasticity (ARCH, GARCH, EGARCH, TGARCH. The results indicate that there is a partial relationship between the evolution of the Tunisian dinar exchange rates and macroeconomic variables.

  18. Semiparametric Inference in a GARCH-in-Mean Model

    DEFF Research Database (Denmark)

    Christensen, Bent Jesper; Dahl, Christian Møller; Iglesias, Emma M.

    facilitates the derivation of asymptotic theory under possible nonlinearity of unspecified form of the risk-return tradeoff. Besides the nonlinear GARCH-in-mean effect, our specification accommodates exogenous regressors that are typically used as conditioning variables entering linearly in the mean equation......, such as the dividend yield. Using the profile likelihood approach, we show that our estimator under stated conditions is consistent, asymp- totically normal, and efficient, i.e. it achieves the semiparametric lower bound. A sampling experiment provides evidence on finite sample properties as well as comparisons...... with the fully parametric approach and the iterative semiparametric approach using a parametric initial esti- mate proposed by Conrad and Mammen (2008). An empirical application to the daily S&P 500 stock market returns suggests that the linear relation between conditional expected return and conditional...

  19. In-beam activation analysis facility at MLZ, Garching

    Energy Technology Data Exchange (ETDEWEB)

    Révay, Zs., E-mail: zsolt.revay@frm2.tum.de [Heinz Maier-Leibniz Zentrum (MLZ), Technische Universität München, 85748 Garching (Germany); Kudějová, P.; Kleszcz, K.; Söllradl, S. [Heinz Maier-Leibniz Zentrum (MLZ), Technische Universität München, 85748 Garching (Germany); Genreith, Christoph [Heinz Maier-Leibniz Zentrum (MLZ), Technische Universität München, 85748 Garching (Germany); Institute of Energy and Climate Research, IEK-6: Nuclear Waste and Reactor Safety Fuel Cycle, Forschungszentrum Jülich GmbH in der Helmholtz-Gemeinschaft, 52428 Jülich (Germany)

    2015-11-01

    The reconstruction of the prompt gamma activation analysis facility and the construction of the new low-background counting chamber at MLZ, Garching is presented. The improvement of the shielding and its effect on the radiation background is shown. The setting up and the fine-tuning of the electronics and their characterization are also discussed. The upgraded facility has been demonstrated to be applicable for both PGAA and neutron activation analysis using in-beam activation and decay counting in the low-background counting chamber. - Highlights: • Radiation background at the PGAA facility was efficiently reduced. • In-beam irradiation facility in the strongest neutron beam. • The best signal-to-background ratio at a PGAA facility was achieved.

  20. ARMA-GARCH Model and temporal precedence between stock indices

    Directory of Open Access Journals (Sweden)

    Diego Garcia Angelico

    2016-03-01

    Full Text Available Faced with the need for risk valuation of financial assets, investors demand sophisticated methods of modeling that can judge the variability of their investments. At the same time, financial globalization has been characterized by common movements and trends between different international markets. In this context, the main objective of this paper was to model the statistical volatility of the Bovespa Index (Ibovespa and the Dow Jones Industrial Average Index, using ARMA-GARCH adjustments, in addition to checking the existence of a long- -term balance and temporal precedence between these variables, using the Johansen co-integration and Granger causality tests, respectively. The results established a higher heterogeneous variance for Ibovespa and the existence of temporal precedence for the Dow Jones Index, despite the absence of any long-term balance between the series. It is understood that the latter behavior may have been caused by the existing difference between the conditional heteroscedasticity of each index.

  1. Extraterrestrial Nucleobases in Carbonaceous Chondrites

    Science.gov (United States)

    Martins, Z.; Botta, O.; Fogel, M.; Sephton, M.; Glavin, D.; Watson, J.; Dworkin, J.; Schwartz, A.; Ehrenfreund, P.

    . Our stable carbon isotope measurements clearly demonstrate that the nucleobases in the Murchison meteorite are indigenous to the meteorite, and clearly differ from the values determined for the terrestrial nucleobases measured in the soil collected at the impact site. These results support the hypothesis that nucleobases were exogenously delivered to the early Earth, and may have been important for the prebiotic chemistry on our young planet. With regard to the detection of traces of life on other planets such as Mars it is essential to characterize organic materials that have been exogenously delivered to the early planets. The analysis of the composition and isotopic fractionation of extraterrestrial material using complementary techniques can provide crucial insights into the formation of our Solar System, extraterrestrial delivery processes and subsequent addition and incorporation into the carbonaceous material available on the young planets. Ultimately, these parameters form an essential reference point for interpreting biosignatures that may be left in the ancient rock record on a planetary body. References: [1] Hayatsu R. et al. 1975. Geochimica et Cosmochimica Acta 39: 471- 488. [2] Folsome C. E. et al. 1971. Nature 232: 108-109. [3] Stoks P. G. & Schwartz A. W. 1979. Nature 282: 709-710. [4] Stoks P.G. & Schwartz A. W. 1981. Geochimica et Cosmochimica Acta 45: 563-569. [5] Shimoyama A. et al. 1990. Geochemical Journal 24: 343-348. [6] Martins Z. et al. 2004. Meteoritics & Planetary Science 39: A5145. 2

  2. Which pricing approach for options under GARCH with non-normal innovations?

    DEFF Research Database (Denmark)

    Simonato, Jean-Guy; Stentoft, Lars

    implemented in both pricing frameworks. The model uses a parsimonious GARCH specification with skewed and leptokurtic Johnson Su innovations together with either the equilibrium based framework or the no-arbitrage based framework. Using a large sample of options on the S&P 500 index, we find that the two......Two different pricing frameworks are typically used in the literature when pricing options under GARCH with non-normal innovations: the equilibrium approach and the no-arbitrage approach. Each framework can accommodate various forms of GARCH and innovation distributions, but empirical...... implementation and tests are typically done in one framework or the other because of the computational challenges that are involved in obtaining the relevant pricing parameters. We contribute to the literature by comparing and documenting the empirical performance of a GARCH specification which can be readily...

  3. BANK STOCK VOLATILITY AND CONTAGION: AN EMPIRICAL INVESTIGATION WITH APPLICATION OF MULTIVARIATE GARCH MODELS

    National Research Council Canada - National Science Library

    Wided Ben Moussa

    2014-01-01

      This paper uses a multivariate GARCH modelling to describe the relationship between the systemic risk and the stock return in the banking industry in Thailand, Malaysia, Korea, Indonesia and Philippines...

  4. Improving the Estimations of VaR-GARCH Using Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    WANG Chun-feng; LI Gang

    2001-01-01

    In this paper, genetic algorithm (GA) is put forward to improve the accuracy and robustness of the parameters estimation in GARCH models, and the results are applied to calculate value at risk. The computing examples of Dow Jones Index and exchange rate are presented, and the computation results indicate that VaR-GARCH model based on GA outperformed the conventional numerical method on the aspect of computational robustness and accuracy.

  5. GNAR-GARCH model and its application in feature extraction for rolling bearing fault diagnosis

    Science.gov (United States)

    Ma, Jiaxin; Xu, Feiyun; Huang, Kai; Huang, Ren

    2017-09-01

    Given its simplicity of modeling and sensitivity to condition variations, time series model is widely used in feature extraction to realize fault classification and diagnosis. However, nonlinear and nonstationary characteristics common in fault signals of rolling bearing bring challenges to the diagnosis. In this paper, a hybrid model, the combination of a general expression for linear and nonlinear autoregressive (GNAR) model and a generalized autoregressive conditional heteroscedasticity (GARCH) model, (i.e., GNAR-GARCH), is proposed and applied to rolling bearing fault diagnosis. An exact expression of GNAR-GARCH model is given. Maximum likelihood method is used for parameter estimation and modified Akaike Information Criterion is adopted for structure identification of GNAR-GARCH model. The main advantage of this novel model over other models is that the combination makes the model suitable for nonlinear and nonstationary signals. It is verified with statistical tests that contain comparisons among the different time series models. Finally, GNAR-GARCH model is applied to fault diagnosis by modeling mechanical vibration signals including simulation and real data. With the parameters estimated and taken as feature vectors, k-nearest neighbor algorithm is utilized to realize the classification of fault status. The results show that GNAR-GARCH model exhibits higher accuracy and better performance than do other models.

  6. Estimation of value-at-risk for energy commodities via fat-tailed GARCH models

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Jui-Cheng [Department of Finance, Yuanpei University, N0.306. Yuanpei St. Hsin Chu 300 (China); Lee, Ming-Chih; Liu, Hung-Chun [Department of Banking and Finance, Tamkang University, 151 Ying-Chuan Road, Tamsui 251, Taipei County (China)

    2008-05-15

    The choice of an appropriate distribution for return innovations is important in VaR applications owing to its ability to directly affect the estimation quality of the required quantiles. This study investigates the influence of fat-tailed innovation process on the performance of one-day-ahead VaR estimates using three GARCH models (GARCH-N, GARCH-t and GARCH-HT). Daily spot prices of five energy commodities (WTI crude oil, Brent crude oil, heating oil 2, propane and New York Harbor Conventional Gasoline Regular) are used to compare the accuracy and efficiency of the VaR models. Empirical results suggest that for asset returns that exhibit leptokurtic and fat-tailed features, the VaR estimates generated by the GARCH-HT models have good accuracy at both low and high confidence levels. Additionally, MRSB indicates that the GARCH-HT model is more efficient than alternatives for most cases at high confidence levels. These findings suggest that the heavy-tailed distribution is more suitable for energy commodities, particularly VaR calculation. (author)

  7. The biological universe. The twentieth century extraterrestrial life debate and the limits of science.

    Science.gov (United States)

    Dick, S. J.

    Throughout the twentieth century, from the furor over Percival Lowell's claim of canals on Mars to the sophisticated Search for Extraterrestrial Intelligence, otherworldly life has often intrigued and occasionally consumed science and the public. Does 'biological law' reign throughout the universe? Are there other histories, religions, and philosophies outside of those on Earth? Do extraterrestrial minds ponder the mysteries of the universe? The attempts to answer these often asked questions form one of the most interesting chapters in the history of science and culture, and this is the first book to provide a rich and colorful history of those attempts during the twentieth century. Covering a broad range of topics, including the search for life in the solar system, the origins of life, UFOs, and aliens in science fiction, the author shows how the concept of extraterrestrial intelligence is a world view of its own, a 'biophysical cosmology' that seeks confirmation no less than physical views of the universe.

  8. The biological universe: the twentieth-century extraterrestrial life debate and the limits of science

    Science.gov (United States)

    Dick, Steven J.

    Throughout the twentieth century, from the furor over Percival Lowell's claim of canals on Mars to the sophisticated Search for Extraterrestrial Intelligence, otherworldly life has often intrigued and occasionally consumed science and the public. Does `biological law' reign throughout the universe? Are there other histories, religions, and philosophies outside of those on Earth? Do extraterrestrial minds ponder the mysteries of the universe? The attempts toanswer these often asked questions form one of the most interesting chapters in the history of science and culture, and The Biological Universe is the first book to provide a rich and colorful history of those attempts during the twentieth century. Covering a broad range of topics, including the search for life in the solar system, the origins of life, UFOs, and aliens in science fiction, Steven J. Dick shows how the concept of extraterrestrial intelligence is a world view of its own, a `biophysical cosmology' that seeks confirmation no less than physical views of the universe.

  9. Investigation of Supercritical Water Phenomena for Space and Extraterrestrial Application

    Science.gov (United States)

    Hicks, Michael C.; Hegde, Uday G.; Fisher, John W.

    2012-01-01

    The cost of carrying or resupplying life support resources for long duration manned space exploration missions such as a mission to Mars is prohibitive and requires the development of suitable recycling technologies. Supercritical Water Oxidation (SCWO) has been identified as an attractive candidate for these extended missions because (i) pre-drying of wet waste streams is not required, (ii) product streams are relatively benign, microbially inert, and easily reclaimed, (iii) waste conversion is complete and relatively fast, and (iv) with proper design and operation, reactions can be self-sustaining. Initial work in this area at NASA was carried out at the Ames Research Center in the 1990 s with a focus on understanding the linkages between feed stock preparation (i.e., particle size and distribution) of cellulosic based waste streams and destruction rates under a range of operating temperatures and pressures. More recently, work in SCWO research for space and extra-terrestrial application has been performed at NASA s Glenn Research Center where various investigations, with a particular focus in the gravitational effects on the thermo-physical processes occurring in the bulk medium, have been pursued. In 2010 a collaborative NASA/CNES (the French Space Agency) experiment on the critical transition of pure water was conducted in the long duration microgravity environment on the International Space Station (ISS). A follow-on experiment, to study the precipitation of salt in sub-critical, trans-critical and supercritical water is scheduled to be conducted on the ISS in 2013. This paper provides a brief history of NASA s earlier work in SCWO, discusses the potential for application of SCWO technology in extended space and extraterrestrial missions, describes related research conducted on the ISS, and provides a list of future research activities to advance this technology in both terrestrial and extra-terrestrial applications.

  10. Extraterrestrial Life: Processes, Implications, and Applications.

    Science.gov (United States)

    Molyson, Joseph T.

    Provided are background materials relating the study of extraterrestrial life to common biological principles. A history of the creation of the sun and earth is included, as well as a summary of one current theory regarding the origin of life on earth. Relationships are identified regarding possible origins of life on other planets. Factors…

  11. MCMC simulation of GARCH model to forecast network traffic load

    Directory of Open Access Journals (Sweden)

    Akhter Raza Syed

    2012-05-01

    Full Text Available The performance of a computer network can be enhanced by increasing number of servers, upgrading the hardware, and gaining additional bandwidth but this solution require the huge amount to invest. In contrast to increasing the bandwidth and hardware resources, network traffic modeling play a significant role in enhancing the network performance. As the emphasis of telecommunication service providers shifted towards the high-speed networks providing integrated services at a prescribed Quality of Service (QoS, the role of accurate traffic models in network design and network simulation becomes ever more crucial. We analyze a traffic volume time series of internet requests made to a workstation. This series exhibits a long-range dependence and self-similarity in large time scale and exhibits multifractal in small time scale. In this paper, for this time series, we proposed Generalized Autoregressive Conditional Heteroscedastic, (GARCH model, and practical techniques for model fitting, Markov Chain Monte Carlo simulation and forecasting issues are demonstrated. The proposed model provides us simple and accurate approach for simulating internet data traffic patterns.

  12. Ettore Spalletti: Salle des départs a Garches

    Directory of Open Access Journals (Sweden)

    Andrea Dall'Asta

    2012-06-01

    Full Text Available Ettore Spalletti re-inventa nel 1996 l’obitorio dell’ospedale Raymond Poincaré a Garches - alle porte di Parigi. È uno spazio privo di simboli religiosi, in cui i corpi, posti nella bara, sono esposti all’ultimo sguardo dei familiari e degli amici. È la Salle des départs, sala delle partenze, in cui ogni uomo è chiamato a soggiornare - musulmano, cristiano, non credente – per il breve transito dal mondo della vita a quello della morte, verso una nuova vita. L’intento di Spalletti è quello di umanizzare un luogo che aiuti le persone a elaborare il lutto, infondendo pace e serenità. Da uno spazio anonimo, grazie alla forza espressiva del colore azzurro, come quello del manto di una Madonna che accoglie i suoi figli, l’artista ci fa immergere in un luogo che si presenta come l’incarnazione della purezza, diventando simbolo della promessa della trascendenza e dell’assoluto.

  13. Value at risk estimation using independent component analysis-generalized autoregressive conditional heteroscedasticity (ICA-GARCH) models.

    Science.gov (United States)

    Wu, Edmond H C; Yu, Philip L H; Li, W K

    2006-10-01

    We suggest using independent component analysis (ICA) to decompose multivariate time series into statistically independent time series. Then, we propose to use ICA-GARCH models which are computationally efficient to estimate the multivariate volatilities. The experimental results show that the ICA-GARCH models are more effective than existing methods, including DCC, PCA-GARCH, and EWMA. We also apply the proposed models to compute value at risk (VaR) for risk management applications. The backtesting and the out-of-sample tests validate the performance of ICA-GARCH models for value at risk estimation.

  14. Estimating the Volatility of Cocoa Price Return with ARCH and GARCH Models

    Directory of Open Access Journals (Sweden)

    Lya Aklimawati

    2013-08-01

    Full Text Available Dynamics of market changing as a result of market liberalization have an impact on agricultural commodities price fluctuation. High volatility on cocoa price movement reflect its price and market risk. Because of price and market uncertainty, the market players face some difficulties to make a decision in determining business development. This research was conducted to 1 understand the characteristics of cocoa price movement in cocoa futures trading, and 2analyze cocoa price volatility using ARCH and GARCH type model. Research was carried out by direct observation on the pattern of cocoa price movement in the futures trading and volatility analysis based on secondary data. The data was derived from Intercontinental Exchange ( ICE Futures U.S. Reports. The analysis result showed that GARCH is the best model to predict the value of average cocoa price return volatility, because it meets criteria of three diagnostic checking, which are ARCH-LM test, residual autocorrelation test and residual normality test. Based on the ARCH-LM test, GARCH (1,1did not have heteroscedasticity, because p-value  2 (0.640139and F-statistic (0.640449 were greater than 0.05. Results of residual autocorrelation test indicated that residual value of GARCH (1,1 was random, because the statistic value of Ljung-Box (LBon the 36 th lag is smaller than the statistic value of  2. Whereas, residual normality test concluded the residual of GARCH (1,1 were normally distributed, because AR (29, MA (29, RESID (-1^2, and GARCH (-1 were significant at 5% significance level. Increasing volatility value indicate high potential risk. Price risk can be reduced by managing financial instrument in futures trading such as forward and futures contract, and hedging. The research result also give an insight to the market player for decision making and determining time of hedging. Key words: Volatility, price, cocoa, GARCH, risk, futures trading

  15. Analysis of GARCH modeling in financial markets: an approach based on technical analysis strategies

    Directory of Open Access Journals (Sweden)

    Mircea Cristian Gherman

    2011-08-01

    Full Text Available In this paper we performed an analysis in order the make an evidence of GARCH modeling on the performances of trading rules applied for a stock market index. Our study relays on the overlap between econometrical modeling, technical analysis and a simulation computing technique. The non-linear structures presented in the daily returns of the analyzed index and also in other financial series, together with the phenomenon of volatility clustering are premises for applying a GARCH model. In our approach the standardized GARCH innovations are resampled using the bootstrap method. On the simulated data are then applied technical analysis trading strategies. For all the simulated paths the “p-values” are computed in order to verify that the hypothesis concerning the goodness of fit for GARCH model on the BET index is accepted. The processed data with trading rules are showing evidence that GARCH model is a good choice for econometrical modeling of financial time series including the romanian exchange trade index.

  16. Psycholinguistics and the Search for Extraterrestrial Intelligence

    Directory of Open Access Journals (Sweden)

    Lidija Krotenko

    2017-09-01

    Full Text Available The author of the article reveals the possibilities of psycholinguistics in the identifi cation and interpretation of languages and texts of Alien Civilizations. The author combines modern interdisciplinary research in psycholinguistics with the theory “Evolving Matter” proposed by Oleg Bazaluk and concludes that the identifi cation of languages and texts of Alien Civilizations, as well as the communication of terrestrial civilization with Extraterrestrial Intelligence, is in principle possible. To that end, it is necessary to achieve the required level of the modeling of neurophilosophy and to include these achievements of modern psycholinguistics studies: а language acquisition; b language comprehension; c language production; d second language acquisition. On the one hand, the possibilities of neurophilosophy to accumulate and model advanced neuroscience research; on the other hand, highly specialized psycholinguistic studies in language evolution are able to provide the communication of terrestrial civilization with Extraterrestrial Intelligence.

  17. Targeting estimation of CCC-GARCH models with infinite fourth moments

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Søndergaard

    is required if one wants to perform inference in GARCH models relying on asymptotic normality of the estimator,see Pedersen and Rahbek (2014) and Francq et al. (2011). Such moment conditions may not be satisfied in practice for financial returns highlighting a large drawback of variance targeting estimation......As an alternative to quasi-maximum likelihood, targeting estimation is a much applied estimation method for univariate and multivariate GARCH models. In terms of variance targeting estimation recent research has pointed out that at least finite fourth-order moments of the data generating process....... In this paper we consider the large-sample properties of the variance targeting estimator for the multivariate extended constant conditional correlation GARCH model when the distribution of the data generating process has infinite fourth moments. Using non-standard limit theory we derive new results...

  18. Targeting estimation of CCC-GARCH models with infinite fourth moments

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Søndergaard

    As an alternative to quasi-maximum likelihood, targeting estimation is a much applied estimation method for univariate and multivariate GARCH models. In terms of variance targeting estimation recent research has pointed out that at least finite fourth-order moments of the data generating process...... is required if one wants to perform inference in GARCH models relying on asymptotic normality of the estimator,see Pedersen and Rahbek (2014) and Francq et al. (2011). Such moment conditions may not be satisfied in practice for financial returns highlighting a large drawback of variance targeting estimation....... In this paper we consider the large-sample properties of the variance targeting estimator for the multivariate extended constant conditional correlation GARCH model when the distribution of the data generating process has infinite fourth moments. Using non-standard limit theory we derive new results...

  19. Forecasting crude oil market volatility. Further evidence using GARCH-class models

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yu; Huang, Dengshi [School of Economics and Management, Southwest Jiaotong University (China); Wang, Yudong [Antai College of Economics and Management, Shanghai Jiaotong University (China)

    2010-11-15

    This paper extends the work of Kang et al. (2009). We use a greater number of linear and nonlinear generalized autoregressive conditional heteroskedasticity (GARCH) class models to capture the volatility features of two crude oil markets - Brent and West Texas Intermediate (WTI). The one-, five- and twenty-day out-of-sample volatility forecasts of the GARCH-class models are evaluated using the superior predictive ability test and with more loss functions. Unlike Kang et al. (2009), we find that no model can outperform all of the other models for either the Brent or the WTI market across different loss functions. However, in general, the nonlinear GARCH-class models, which are capable of capturing long-memory and/or asymmetric volatility, exhibit greater forecasting accuracy than the linear ones, especially in volatility forecasting over longer time horizons, such as five or twenty days. (author)

  20. International evidence on crude oil price dynamics. Applications of ARIMA-GARCH models

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Hassan [Department of Economics, Illinois State University, Normal, IL 61790-4200 (United States); Su, Lixian [Graduate Student, Department of Economics, Illinois State University, Normal, IL 61790-4200 (United States)

    2010-09-15

    We examine the usefulness of several ARIMA-GARCH models for modeling and forecasting the conditional mean and volatility of weekly crude oil spot prices in eleven international markets over the 1/2/1997-10/3/2009 period. In particular, we investigate the out-of-sample forecasting performance of four volatility models - GARCH, EGARCH and APARCH and FIGARCH over January 2009 to October 2009. Forecasting results are somewhat mixed, but in most cases, the APARCH model outperforms the others. Also, conditional standard deviation captures the volatility in oil returns better than the traditional conditional variance. Finally, shocks to conditional volatility dissipate at an exponential rate, which is consistent with the covariance-stationary GARCH models than the slow hyperbolic rate implied by the FIGARCH alternative. (author)

  1. Network Traffic Based on GARCH-M Model and Extreme Value Theory

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    GARCH-M (generalized autoregressive conditional heteroskedasticity in the mean) model is used to analyse the volatility clustering phenomenon in mobile communication network traffic.Normal distribution, t distribution and generalized Pareto distribution assumptions are adopted respectively to simulate the random component in the model. The demonstration of the quantile of network traffic series indicates that common GARCH-M model can partially deal with the "fat tail"problem. However, the "fat tail" characteristic of the random component directly affects the accuracy of the calculation. Even t distribution is based on the assumption for all the data. On the other hand, extreme value theory, which only concentrates on the tail distribution, can provide more accurate result for high quantiles. The best result is obtained based on the generalized Pareto distribution assumption for the random component in the GARCH-M model.

  2. Asymptotic Theory for the QMLE in GARCH-X Models with Stationary and Non-Stationary Covariates

    DEFF Research Database (Denmark)

    Han, Heejoon; Kristensen, Dennis

    This paper investigates the asymptotic properties of the Gaussian quasi-maximum-likelihood estimators (QMLE’s) of the GARCH model augmented by including an additional explanatory variable - the so-called GARCH-X model. The additional covariate is allowed to exhibit any degree of persistence as ca...

  3. GARCH based artificial neural networks in forecasting conditional variance of stock returns

    Directory of Open Access Journals (Sweden)

    Josip Arnerić

    2014-12-01

    Full Text Available Portfolio managers, option traders and market makers are all interested in volatility forecasting in order to get higher profits or less risky positions. Based on the fact that volatility is time varying in high frequency data and that periods of high volatility tend to cluster, the most popular models in modelling volatility are GARCH type models because they can account excess kurtosis and asymmetric effects of financial time series. A standard GARCH(1,1 model usually indicates high persistence in the conditional variance, which may originate from structural changes. The first objective of this paper is to develop a parsimonious neural networks (NN model, which can capture the nonlinear relationship between past return innovations and conditional variance. Therefore, the goal is to develop a neural network with an appropriate recurrent connection in the context of nonlinear ARMA models, i.e., the Jordan neural network (JNN. The second objective of this paper is to determine if JNN outperforms the standard GARCH model. Out-of-sample forecasts of the JNN and the GARCH model will be compared to determine their predictive accuracy. The data set consists of returns of the CROBEX index daily closing prices obtained from the Zagreb Stock Exchange. The results indicate that the selected JNN(1,1,1 model has superior performances compared to the standard GARCH(1,1 model. The contribution of this paper can be seen in determining the appropriate NN that is comparable to the standard GARCH(1,1 model and its application in forecasting conditional variance of stock returns. Moreover, from the econometric perspective, NN models are used as a semi-parametric method that combines flexibility of nonparametric methods and the interpretability of parameters of parametric methods.

  4. The relationship between trading volumes, number of transactions, and stock volatility in GARCH models

    Science.gov (United States)

    Takaishi, Tetsuya; Chen, Ting Ting

    2016-08-01

    We examine the relationship between trading volumes, number of transactions, and volatility using daily stock data of the Tokyo Stock Exchange. Following the mixture of distributions hypothesis, we use trading volumes and the number of transactions as proxy for the rate of information arrivals affecting stock volatility. The impact of trading volumes or number of transactions on volatility is measured using the generalized autoregressive conditional heteroscedasticity (GARCH) model. We find that the GARCH effects, that is, persistence of volatility, is not always removed by adding trading volumes or number of transactions, indicating that trading volumes and number of transactions do not adequately represent the rate of information arrivals.

  5. Importance of the macroeconomic variables for variance prediction: A GARCH-MIDAS approach

    DEFF Research Database (Denmark)

    Asgharian, Hossein; Hou, Ai Jun; Javed, Farrukh

    2013-01-01

    This paper aims to examine the role of macroeconomic variables in forecasting the return volatility of the US stock market. We apply the GARCH-MIDAS (Mixed Data Sampling) model to examine whether information contained in macroeconomic variables can help to predict short-term and long-term compone......This paper aims to examine the role of macroeconomic variables in forecasting the return volatility of the US stock market. We apply the GARCH-MIDAS (Mixed Data Sampling) model to examine whether information contained in macroeconomic variables can help to predict short-term and long...

  6. Tracers of the Extraterrestrial Component in Sediments and Inferences for Earth's Accretion History

    Science.gov (United States)

    Kyte, Frank T.

    2003-01-01

    The study of extraterrestrial matter in sediments began with the discovery of cosmic spherules during the HMS Challenger Expedition (1873-1876), but has evolved into a multidisciplinary study of the chemical, physical, and isotopic study of sediments. Extraterrestrial matter in sediments comes mainly from dust and large impactors from the asteroid belt and comets. What we know of the nature of these source materials comes from the study of stratospheric dust particles, cosmic spherules, micrometeorites, meteorites, and astronomical observations. The most common chemical tracers of extraterrestrial matter in sediments are the siderophile elements, most commonly iridium and other platinum group elements. Physical tracers include cosmic and impact spherules, Ni-rich spinels, meteorites, fossil meteorites, and ocean-impact melt debris. Three types of isotopic systems have been used to trace extraterrestrial matter. Osmium isotopes cannot distinguish chondritic from mantle sources, but provide a useful tool in modeling long-term accretion rates. Helium isotopes can be used to trace the long-term flux of the fine fraction of the interplanetary dust complex. Chromium isotopes can provide unequivocal evidence of an extraterrestrial source for sediments with high concentrations of meteoritic Cr. The terrestrial history of impacts, as recorded in sediments, is still poorly understood. Helium isotopes, multiple Ir anomalies, spherule beds, and craters all indicate a comet shower in the late Eocene. The Cretaceous-Tertiary boundary impact event appears to have been caused by a single carbonaceous chondrite projectile, most likely of asteroid origin. Little is known of the impact record in sediments from the rest of the Phanerozoic. Several impact deposits are known in the Precambrian, including several possible mega-impacts in the Early Archean.

  7. Extraterrestrial altruism evolution and ethics in the cosmos

    CERN Document Server

    2014-01-01

    Extraterrestrial Altruism examines a basic assumption of the Search for Extraterrestrial Intelligence (SETI): that extraterrestrials will be transmitting messages to us for our benefit. This question of whether extraterrestrials will be altruistic has become increasingly important in recent years as SETI scientists have begun contemplating transmissions from Earth to make contact. Should we expect altruism to evolve throughout the cosmos, or is this only wishful thinking? Would this make biological sense? Is it dangerous to send messages to other worlds, as Stephen Hawking has suggested? Would extraterrestrial societies be based on different ethical principles? Extraterrestrial Altruism explores these and related questions about the motivations of civilizations beyond Earth, providing new insights that are critical for SETI. Chapters are authored by leading scholars from diverse disciplines—anthropology, astronomy, biology, chemistry, computer science, cosmology, engineering, history of science, law, philos...

  8. 基于GARCH-M模型的人民币汇率预测%Renminbi exchange rate forecast based on GARCH-M Model

    Institute of Scientific and Technical Information of China (English)

    闫海峰; 谢莉莉

    2009-01-01

    在经济全球化的形势下,人民币的走势是关系到中国外贸企业生存、国际地位以及国家金融环境的重要因素,因此对人民币/美元汇率进行预测是十分有必要的.通过对GARCH-M模型在预测人民币美元汇率的可行性,时间序列存在异方差性和自相关性的论证,建立相应的GARCH(1,1)-M模型,并运用模型对美元/人民币汇率进行预测.表明在现实中可以运用GARCH-M模型进行汇率趋势预测,但是由于检验的数据较少,所以不能达到精确的预期目的.

  9. On Diagnostic Checking of Vector ARMA-GARCH Models with Gaussian and Student-t Innovations

    Directory of Open Access Journals (Sweden)

    Yongning Wang

    2013-04-01

    Full Text Available This paper focuses on the diagnostic checking of vector ARMA (VARMA models with multivariate GARCH errors. For a fitted VARMA-GARCH model with Gaussian or Student-t innovations, we derive the asymptotic distributions of autocorrelation matrices of the cross-product vector of standardized residuals. This is different from the traditional approach that employs only the squared series of standardized residuals. We then study two portmanteau statistics, called Q1(M and Q2(M, for model checking. A residual-based bootstrap method is provided and demonstrated as an effective way to approximate the diagnostic checking statistics. Simulations are used to compare the performance of the proposed statistics with other methods available in the literature. In addition, we also investigate the effect of GARCH shocks on checking a fitted VARMA model. Empirical sizes and powers of the proposed statistics are investigated and the results suggest a procedure of using jointly Q1(M and Q2(M in diagnostic checking. The bivariate time series of FTSE 100 and DAX index returns is used to illustrate the performance of the proposed portmanteau statistics. The results show that it is important to consider the cross-product series of standardized residuals and GARCH effects in model checking.

  10. Day of the week effect on the Zimbabwe Stock Exchange: A non-linear GARCH analysis

    Directory of Open Access Journals (Sweden)

    Batsirai Winmore Mazviona

    2015-11-01

    Full Text Available This study analysed the day of the week effect on the Zimbabwe Stock Exchange (ZSE by taking into account volatility of returns. The purpose of the study was to establish whether daily mean returns across a trading week differ from each other. We employ a non-linear approach in modelling the day of the week effects. In particular, we used the Generalised Autoregressive Conditional Heteroscedasticity (GARCH and the Exponential GARCH (EGARCH models. We used industrial and mining daily closing indices data from 19 February 2009 to 31 December 2013. The data was retrieved from the ZSE website. EViews 7 software was utilised for data analysis. In order to test the null hypothesis of equality of daily mean returns, a Wald test was carried out. The Wald F-statistic rejected the null hypothesis of equality of mean returns for the industrial index. We found the traditional negative Monday and positive Friday effect for the industrial index in GARCH (1,1 and EGARCH (1,1 models. The GARCH (1,1 detected a negative Friday effect and the EGARCH (1,1 detected negative Wednesday effect for the mining index. We found evidence of model dependency for the mining index results.

  11. American Option Pricing using GARCH models and the Normal Inverse Gaussian distribution

    DEFF Research Database (Denmark)

    Stentoft, Lars Peter

    In this paper we propose a feasible way to price American options in a model with time varying volatility and conditional skewness and leptokurtosis using GARCH processes and the Normal Inverse Gaussian distribution. We show how the risk neutral dynamics can be obtained in this model, we interpre....... In particular, improvements are found when considering the smile in implied standard deviations....

  12. Do We Really Need Both BEKK and DCC? A Tale of Two Multivariate GARCH Models

    NARCIS (Netherlands)

    M. Caporin (Massimiliano); M.J. McAleer (Michael)

    2010-01-01

    textabstractThe management and monitoring of very large portfolios of financial assets are routine for many individuals and organizations. The two most widely used models of conditional covariances and correlations in the class of multivariate GARCH models are BEKK and DCC. It is well known that BEK

  13. Comprehensive evaluation of ARMA-GARCH(-M) approaches for modeling the mean and volatility of wind speed

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Heping; Erdem, Ergin; Shi, Jing [Department of Industrial and Manufacturing Engineering, North Dakota State University, Dept. 2485, PO Box 6050, Fargo, ND 58108 (United States)

    2011-03-15

    Accurately modeling the mean and volatility of wind speed can be beneficial to effective wind energy utilization. For this purpose, this paper evaluates the effectiveness of autoregressive moving average-generalized autoregressive conditional heteroscedasticity (ARMA-GARCH) approaches for modeling the mean and volatility of wind speed. Five different GARCH approaches are included, and each consists of an original form and a modified form, GARCH-in-mean (GARCH-M). As a result, 10 different model structures are evaluated, based on the 7-year hourly wind speed data collected at four different heights from an observation site in Colorado, USA. Multiple evaluation methods of modeling sufficiency are used. The results show that the ARMA-GARCH(-M) approaches can effectively catch the trend change of the mean and volatility of wind speed. Also, the volatility of wind speed has the nonlinear and asymmetric time-varying feature, and the ARMA-GARCH-M structures can consistently improve the modeling sufficiency of mean wind speed. As the height increases, the explanatory power of all ARMA-GARCH(-M) models slightly deteriorates. On the other hand, no single model structure outperforms the others at all heights, and this confirms that for any wind speed dataset, the potential models should be evaluated to find the most appropriate one for the highest modeling sufficiency. (author)

  14. Musical Structures and Search for Extraterrestrials

    Science.gov (United States)

    Lefebvre, Vladimir A.

    Recent findings in cognitive phsychology indicate connections between human feelings and musical scales, on the one hand, and the laws of thermodynamics, on the other. The existence of such a deep correlations allows us to suggest the hypothesis that music is inherent not only to the human beings but to other sapient creatures as well. It is worth, thus, in our search for extraterrestrial civilizations to conduct a "musical" analysis of the spectra of "suspicious" objects. The results of such analysis of the Doppler spectrum of SS 433 will be presented in this paper.

  15. Radio communications with extra-terrestrial civilizations

    Science.gov (United States)

    Kotelnikov, V. A.

    1974-01-01

    Communications between civilizations within our galaxy at the present level of radio engineering is possible, although civilizations must begin to search for each other to achieve this. If an extra-terrestrial civilization possessing a technology at our level wishes to make itself known and will transmit special radio signals to do this, then it can be picked up by us at a distance of several hundreds of light years using already existing radio telescopes and specially built radio receivers. If it wishes, this civilization can also send us information without awaiting our answer.

  16. Theology after contact: religion and extraterrestrial intelligent life.

    Science.gov (United States)

    Haught, J F

    2001-12-01

    The prospect of encountering extraterrestrial intelligent life raises important questions for religion and theology. Even if an actual encounter with extraterrestrials never actually takes place, or proves impractical, terrestrial religious thought already has resources that can render intelligible and allow us theologically to appreciate such an eventuality.

  17. Extraterrestrial Radiation Chemistry and Molecular Astronomy

    Science.gov (United States)

    Hudson, Reggie L.; Moore, Marla H.

    2009-01-01

    Astronomical observations of both solar system and interstellar regions have revealed a rich chemical inventory that includes most classes of organic molecules and selected inorganics. For example, gas-phase ethylene glycol and SOz have been observed by astronomers, while solidphase detections include OCS, H2O2 , and the cyanate anion.' All of these are found in environments that are, by earthly standards, exceedingly hostile: temperatures of 10 - 100 K, miniscule densities, and near-ubiquitous ionizing-radiation fields. Beyond the simplest chemical species, these conditions have made it difficult-to-impassible to account for the observed molecular abundances using gas-phase chemistry, suggesting solid-phase reactions play an important role. In extraterrestrial environments, cosmic rays, UV photons, and magnetospheric radiation all drive chemical reactions, even at cryogenic temperatures. To study this chemistry, radiation astrochemists conduct experiments on icy materials, frozen under vacuum and exposed to sources such as keV electrons and MeV protons. Compositional changes usually are followed with IR spectroscopy and, in selected cases, more-sensitive mass-spectral techniques. This talk will review some recent results on known and suspected extraterrestrial molecules and ions. Spectra and reaction pathways will be presented, and predictions made for interstellar chemistry and the chemistry of selected solar system objects. Some past radiation-chemical contributions, and future needs, will be explored.

  18. Is Your Gut Conscious? Is an Extraterrestrial?

    Science.gov (United States)

    Vos Post, Jonathan

    2011-10-01

    This paper speculates on questions intending to be taken scientifically rather than metaphysically: "Can the human gut (enteric nervous system) be conscious?"; "Can your immune system think?"; "Could consciousness be coded in DNA?"; "What do we mean when asserting that an Extraterrestrial is Thinking, or is Conscious? We explore through reference to theory, experiment, and computational models by Christof Koch (Caltech), Barbara Wold (Caltech), and Stuart Kauffman (University of Calgary, Tampere University of Technology, Santa Fe Institute). We use a tentative new definition of thinking, designed to be applicable for humans, cetecea, corvids, artificial intelligences, and extraterrestrial intelligences of any substrate (i.e. Life as We Do Not Know It): "Thinking is the occurrence, transformation, and storage in a mind or brain (or simulation thereof) of information-bearing structures (representations) of one kind or another, such as thoughts, concept, percepts, ideas, impressions, notions, rules, schemas, images, phantasms, or subpersonal representations." We use the framework for Consciousness developed by Francis Crick and Christof Koch. We try to describe scientific goals, but discuss Philosophy sufficient to avoid naïve philosophical category errors (thus are careful not to conflate thought, consciousness, and language) Penrose, Hameroff, and Kauffman speculate (differently) that CNS consciousness is a macroscopic quantum phenomenon. Might intestinal, immune system, or genetic regulatory network dynamics exhibit emergent cooperative quantum effects? The speculations are in the context of Evolution by Natural Selection, presumed to operate throughout the Cosmos, and recent work in the foundations of Computational Biology and Quantum Mechanics.

  19. Extraterrestrial Radiation Chemistry and Molecular Astronomy

    Science.gov (United States)

    Hudson, Reggie L.; Moore, Marla H.

    2009-01-01

    Astronomical observations of both solar system and interstellar regions have revealed a rich chemical inventory that includes most classes of organic molecules and selected inorganics. For example, gas-phase ethylene glycol and SOz have been observed by astronomers, while solidphase detections include OCS, H2O2 , and the cyanate anion.' All of these are found in environments that are, by earthly standards, exceedingly hostile: temperatures of 10 - 100 K, miniscule densities, and near-ubiquitous ionizing-radiation fields. Beyond the simplest chemical species, these conditions have made it difficult-to-impassible to account for the observed molecular abundances using gas-phase chemistry, suggesting solid-phase reactions play an important role. In extraterrestrial environments, cosmic rays, UV photons, and magnetospheric radiation all drive chemical reactions, even at cryogenic temperatures. To study this chemistry, radiation astrochemists conduct experiments on icy materials, frozen under vacuum and exposed to sources such as keV electrons and MeV protons. Compositional changes usually are followed with IR spectroscopy and, in selected cases, more-sensitive mass-spectral techniques. This talk will review some recent results on known and suspected extraterrestrial molecules and ions. Spectra and reaction pathways will be presented, and predictions made for interstellar chemistry and the chemistry of selected solar system objects. Some past radiation-chemical contributions, and future needs, will be explored.

  20. Extraterrestrial Intelligence: What Would it Mean?

    Science.gov (United States)

    Impey, Chris

    2015-04-01

    Results from NASA's Kepler mission imply a hundred million Earth-like habitable worlds in the Milky Way galaxy, many of which formed billions of years before the Earth. Each of these worlds is likely to have all of the ingredients needed for biology. The real estate of time and space for the evolution of intelligent life is formidable, begging the question of whether or not we are alone in the universe. The implications of making contact have been explored extensively in science fiction and the popular culture, but less frequently in the serious scientific literature. Astronomers have carried out searches for extraterrestrial intelligence for over half a century, with no success so far. In practice, it is easier to search for alien technology than to discern intelligence of unknown function and form. In this talk, the modes of technology that can currently be detected are summarized, along with the implications of a timing argument than any detected civilization is likely to be much more advanced than ours. Fermi's famous question ``Where Are They?'' is as well posed now as it was sixty years ago. The existence of extraterrestrial intelligence would have profound practical, cultural, and religious implications for humanity.

  1. Our Sky now and then $-$ searches for lost stars and impossible effects as probes of advanced extra-terrestrial civilisations

    OpenAIRE

    Villarroel, Beatriz; Imaz, Iñigo; Bergstedt, Josefine

    2016-01-01

    Searches for extra-terrestrial intelligence (SETI) using large survey data often look for possible signatures of astroengineering. We propose to search for physically impossible effects caused by highly advanced technology, by carrying out a search for disappearing galaxies and Milky Way stars. We select $\\sim$ 10 million objects from USNO-B1.0 with low proper motion ($\\mu$ $

  2. The Search for Extraterrestrial Intelligence in the 1960s: Science in Popular Culture

    Science.gov (United States)

    Smith, Sierra

    2012-01-01

    Building upon the advancement of technology during the Second World War and the important scientific discoveries which have been made about the structure and components of the universe, scientists, especially in radio astronomy and physics, began seriously addressing the possibility of extraterrestrial intelligence in the 1960s. The Search for Extraterrestrial Intelligence (SETI) quickly became one of the most controversial scientific issues in the post Second World War period. The controversy played out, not only in scientific and technical journals, but in newspapers and in popular literature. Proponents for SETI, including Frank Drake, Carl Sagan, and Philip Morrison, actively used a strategy of engagement with the public by using popular media to lobby for exposure and funding. This paper will examine the use of popular media by scientists interested in SETI to popularize and heighten public awareness and also to examine the effects of popularization on SETI's early development. My research has been generously supported by the National Radio Astronomy Observatory.

  3. Searching for extraterrestrial intelligence signals in astronomical spectra, including existing data

    CERN Document Server

    Borra, Ermanno F

    2012-01-01

    The main purpose of this article is to make Astronomers aware that Searches for Extraterrestrial Intelligence can be carried out by analyzing standard astronomical spectra, including those they already have taken. Simplicity is the outstanding advantage of a search in spectra. The spectra can be analyzed by simple eye inspection or a few lines of code that uses Fourier transform software. Theory, confirmed by published experiments, shows that periodic signals in spectra can be easily generated by sending light pulses separated by constant time intervals. While part of this article, like all articles on searches for ETI, is highly speculative the basic physics is sound. In particular, technology now available on Earth could be used to send signals having the required energy to be detected at a target located 1000 light years away. Extraterrestrial Intelligence (ETI) could use these signals to make us aware of their existence. For an ETI, the technique would also have the advantage that the signals could be det...

  4. Measuring the Value-At-Risk of Foreign Exchange Portfolio by a Garch-Evt-Copula Based Model%基于GARCH-EVT-COPULA模型的外汇投资组合风险度量研究

    Institute of Scientific and Technical Information of China (English)

    苟红军; 陈迅; 花拥军

    2015-01-01

    基于巴塞尔协议和商业银行风险管理新视角,本文运用GARCH-EVT-COPULA模型构建了GARCH-EVT-Gaussian-COPULA和GARCH-EVT-t-COPULA两种方法,对美元、欧元、日元和港元四种人民币汇率的等权重投资组合风险进行了度量,优化了极值分布作为COPULA函数边际分布的多序列超阈值比例确定方法,并与历史模拟法、正态方法、蒙特卡罗方法三种传统方法和单用极值方法度量的VaR进行了比较并作返回检验.结果表明:GARCH-EVT-Gaussian-COPULA扣GARCH-EVT-t-COPULA两种方法符合巴塞尔协议的内部模型法(I--)对商业银行风险管理的要求,而且估计结果优于其他四种方法,其中,GARCH-EVT-Gaussian-COPU LA方法的估计结果比GARCH-EVT-t-COPULA方法更有利于节省商业银行的经济资本.

  5. Volatility spillovers of rupee-dollar and rupee-euro exchange rates on Indian stock prices: evidence from GARCH model

    OpenAIRE

    I, Sahadudheen I

    2013-01-01

    This paper examines the effect of volatility in both rupee-dollar and rupee-euro exchange rates on stock prices in India using daily data from 3-Apr-2007 to 30-Mar-2012. Adopting a generalized autoregressive conditional heteroskedasticity (GARCH) and exponential GARCH (EGARCH) model, the study suggests a negative relationship between exchange rate and stock prices in India. Even though India is a major trade partner of European Union, the study couldn’t find any significant statistical effect...

  6. Estimating Price Volatility Structure in Iran’s Meat Market: Application of General GARCH Models

    Directory of Open Access Journals (Sweden)

    Z. Rasouli Birami

    2016-10-01

    Full Text Available Introduction: Over the past few years, the price volatility of agricultural products and food markets has attracted attention of many researchers and policy makers. This growing attention was started from the food price crisis in 2007 and 2008 when major agricultural products faced accelerated price increases and then rapidly decreased. This paper focused on the price volatility of major commodities related to three market levels of Iran’s meat market, including hay (the input level, calf and sheep (the wholesale level and beef and mutton (the retail level. In particular, efforts will made to find more appropriate models for explaining the behavior of volatility of the return series and to identify which return series are more volatile. The effects of good and bad news on the volatility of prices in each return series will also be studied. Materials and Methods: Different GARCH type models have been considered the best for modeling volatility of return series. Nonlinear GARCH models were introduced to capture the effect of good and bad news separately. The paper uses some GARCH type models including GARCH, Exponential GARCH (EGARCH, GJR-GARCH, Threshold GARCH (TGARCH, Simple Asymmetric GARCH (SAGARCH, Power GARCH (PGARCH, Non-linear GARCH (NGARCH, Asymmetric Power GARCH (APGARCH and Non-linear Power GARCH (NPGARCH to model the volatility of hay, calf, sheep, beef and mutton return series. The data on hay, calf, sheep, and beef and mutton monthly prices are published by Iran’s livestock support firm. The paper uses monthly data over the sample period of the May 1992 to the March 2014. Results and Discussion: Descriptive statistics of the studied return series show evidence of skewness and kurtosis. The results here show that all the series has fat tails. The significant p-values for the Ljung-Box Q-statistics mean that the auto-correlation exists in the squared residuals. The presence of unit roots in the return series is confirmed by the

  7. The role of extraterrestrial phenomena in extinction.

    Science.gov (United States)

    Raup, D M

    1988-01-01

    In the several years since the Alvarez report of anomalously high iridium concentrations at the Cretaceous-Tertiary boundary, evidence for the involvement of meteorite impacts in biological extinction has increased dramatically. Much more research will be needed, however, before meteorite impact is established as a general causal factor in extinction. Of ever greater long-term interest is the possibility that other extraterrestrial forces have had important influences on the evolution of life. To recognize the effects of such forces, it will be necessary to coordinate the research of astronomy and paleontology so that testable predictions can be formulated. It is possible that known, systematic changes in the Solar System or Galaxy have had effects on global biology and that these effects have been preserved in the paleontological record.

  8. Can Collimated Extraterrestrial Signals be Intercepted?

    CERN Document Server

    Forgan, Duncan H

    2014-01-01

    The Optical Search for Extraterrestrial Intelligence (OSETI) attempts to detect collimated, narrowband pulses of electromagnetic radiation. These pulses may either consist of signals intentionally directed at the Earth, or signals between two star systems with a vector that unintentionally intersects the Solar System, allowing Earth to intercept the communication. But should we expect to be able to intercept these unintentional signals? And what constraints can we place upon the frequency of intelligent civilisations if we do? We carry out Monte Carlo Realisation simulations of interstellar communications between civilisations in the Galactic Habitable Zone (GHZ) using collimated beams. We measure the frequency with which beams between two stars are intercepted by a third. The interception rate increases linearly with the fraction of communicating civilisations, and as the cube of the beam opening angle, which is somewhat stronger than theoretical expectations, which we argue is due to the geometry of the GHZ...

  9. Stellivore extraterrestrials? Binary stars as living systems

    Science.gov (United States)

    Vidal, Clément

    2016-11-01

    We lack signs of extraterrestrial intelligence (ETI) despite decades of observation in the whole electromagnetic spectrum. Could evidence be buried in existing data? To recognize ETI, we first propose criteria discerning life from non-life based on thermodynamics and living systems theory. Then we extrapolate civilizational development to both external and internal growth. Taken together, these two trends lead to an argument that some existing binary stars might actually be ETI. Since these hypothetical beings feed actively on stars, we call them "stellivores". I present an independent thermodynamic argument for their existence, with a metabolic interpretation of interacting binary stars. The jury is still out, but the hypothesis is empirically testable with existing astrophysical data. article>

  10. The Predictability of GARCH-Type Models on the Returns Volatility of Primary Indonesian Exported Agricultural Commodities

    Directory of Open Access Journals (Sweden)

    Saarce Elsye Hatane

    2011-09-01

    Full Text Available Agricultural sector plays an important role in Indonesia‟s economy; especially for the plantation sub-sector contributing high revenues to Indonesia‟s exporting sectors. The primary agricultural commodities in Indonesian export discussed in this study would be Crude Palm Oil (CPO, Natural Rubber TSR20, Arabica Coffee, Robusta Coffee, Cocoa, White Pepper and Black Pepper. Meanwhile, the returns volatility nature of agricultural commodity is famous. The volatility refers to heteroscedasticity nature of the returns which can be modeled by GARCH-type models. The returns volatility can be describe by the residual of the mean equation and volatility of error variances in the previous periods. The aims of this study are to examine the predictability of GARCH-type models on the returns volatility of those seven agricultural commodities and to determine the best GARCH-type models for each commodity based on the traditional symmetric evaluation statistics. The results find that the predictability of ARCH, GARCH, GARCH-M, EGACRH and TGARCH, as type of GARCH models used in this study, are different for each commodity.

  11. Volatility Nexus Between Stock Market and Macroeconomic Variables in Bangladesh: an Extended GARCH Approach

    Directory of Open Access Journals (Sweden)

    Hasan Md. Abu

    2017-06-01

    Full Text Available This paper examines the volatility of the Bangladesh stock market returns in response to the volatility of the macroeconomic variables employing monthly data of general index of Dhaka Stock Exchange (DSE and four macroeconomic variables (Call Money Rate, Crude Oil Price, Exchange Rate and SENSEX of Bombay Stock Exchange from January 2001 to December 2015. The results of GARCHS models reveal that the volatility of DSE return is significantly guided by the volatility of macroeconomic variables, such as, exchange rate and SENSEX. Specifically, volatility of the DSE is expected to 19% increase by 1% increase of exchange rate. Moreover, the volatility of the Bangladesh stock market returns is expected to dampen down by 2% with an increase in the volatility of Indian stock market of 1%. Thus, we can comment that adding exchange rate or stock returns of India in the GARCH model provides significant knowledge about the behaviour of the DSE volatility.

  12. Conditional Correlation Models of Autoregressive Conditional Heteroskedasticity with Nonstationary GARCH Equations

    DEFF Research Database (Denmark)

    Amado, Cristina; Teräsvirta, Timo

    In this paper we investigate the effects of careful modelling the long-run dynamics of the volatilities of stock market returns on the conditional correlation structure. To this end we allow the individual unconditional variances in Conditional Correlation GARCH models to change smoothly over time......-run and the short-run dynamic behaviour of the volatilities. The structure of the conditional correlation matrix is assumed to be either time independent or to vary over time. We apply our model to pairs of seven daily stock returns belonging to the S&P 500 composite index and traded at the New York Stock Exchange....... The results suggest that accounting for deterministic changes in the unconditional variances considerably improves the fit of the multivariate Conditional Correlation GARCH models to the data. The effect of careful specification of the variance equations on the estimated correlations is variable: in some...

  13. MODEL NON LINIER GARCH (NGARCH UNTUK MENGESTIMASI NILAI VALUE at RISK (VaR PADA IHSG

    Directory of Open Access Journals (Sweden)

    I KOMANG TRY BAYU MAHENDRA

    2015-06-01

    Full Text Available In investment, risk measurement is important. One of risk measure is Value at Risk (VaR. There are many methods that can be used to estimate risk based on VaR framework. One of them Non Linier GARCH (NGARCH model. In this research, determination of VaR used NGARCH model. NGARCH model allowed for asymetric behaviour in the volatility such that “good news” or positive return and “bad news” or negative return. Based on calculations of VaR, the higher of the confidence level and the longer the investment period, the risk was greater. Determination of VaR using NGARCH model was less than GARCH model.

  14. A RBF neural network model with GARCH errors: Application to electricity price forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Leandro dos Santos [Industrial and Systems Engineering Graduate Program, PPGEPS, Pontifical Catholic University of Parana, Imaculada Conceicao, 1155, Zip code 80215-901, Curitiba, Parana (Brazil); Santos, Andre A.P. [Department of Statistics, Universidad Carlos III de Madrid, C/ Madrid, 126, 28903 Getafe, Madrid (Spain)

    2011-01-15

    In this article, we propose a nonlinear forecasting model based on radial basis function neural networks (RBF-NNs) with Gaussian activation functions and robust clustering algorithms to model the conditional mean and a parametric generalized autoregressive conditional heteroskedasticity (GARCH) specification to model the conditional volatility. Instead of calibrating the parameters of the RBF-NNs via numerical simulations, we propose an estimation procedure by which the number of basis functions, their corresponding widths and the parameters of the GARCH model are jointly estimated via maximum likelihood along with a genetic algorithm to maximize the likelihood function. We use this model to provide multi-step-ahead point and direction-of-change forecasts of the Spanish electricity pool prices. (author)

  15. The log-periodic-AR(1)-GARCH(1,1) model for financial crashes

    CERN Document Server

    Gazola, L; Pizzinga, A; Riera, R

    2008-01-01

    This paper intends to meet recent claims for the attainment of more rigorous statistical methodology within the econophysics literature. To this end, we consider an econometric approach to investigate the outcomes of the log-periodic model of price movements, which has been largely used to forecast financial crashes. In order to accomplish reliable statistical inference for unknown parameters, we incorporate an autoregressive dynamic and a conditional heteroskedasticity structure in the error term of the original model, yielding the log-periodic-AR(1)-GARCH(1,1) model. Both the original and the extended models are fitted to financial indices of U. S. market, namely S&P500 and NASDAQ. Our analysis reveal two main points: (i) the log-periodic-AR(1)-GARCH(1,1) model has residuals with better statistical properties and (ii) the estimation of the parameter concerning the time of the financial crash has been improved.

  16. Forecasting the variance and return of Mexican financial series with symmetric GARCH models

    Directory of Open Access Journals (Sweden)

    Fátima Irina VILLALBA PADILLA

    2013-03-01

    Full Text Available The present research shows the application of the generalized autoregresive conditional heteroskedasticity models (GARCH in order to forecast the variance and return of the IPC, the EMBI, the weighted-average government funding rate, the fix exchange rate and the Mexican oil reference, as important tools for investment decisions. Forecasts in-sample and out-of-sample are performed. The covered period involves from 2005 to 2011.

  17. Stock market volatility using GARCH models: Evidence from South Africa and China stock markets

    OpenAIRE

    Cheteni, Priviledge

    2016-01-01

    This study looks into the relationship between stock returns and volatility in South Africa and China stock markets. A Generalized Autoregressive Conditional Heteroscedasticity (GARCH) model is used to estimate volatility of the stock returns, namely, the Johannesburg Stock Exchange FTSE/JSE Albi index and the Shanghai Stock Exchange Composite Index. The sample period is from January 1998 to October 2014. Empirical results show evidence of high volatility in both the JSE market, and the Shang...

  18. Day-ahead electricity price forecasting using wavelet transform combined with ARIMA and GARCH models

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Zhongfu; Zhang, Jinliang; Xu, Jun [North China Electric Power University, Beijing 102206 (China); Wang, Jianhui [Argonne National Laboratory, Argonne, IL 60439 (United States)

    2010-11-15

    This paper proposes a novel price forecasting method based on wavelet transform combined with ARIMA and GARCH models. By wavelet transform, the historical price series is decomposed and reconstructed into one approximation series and some detail series. Then each subseries can be separately predicted by a suitable time series model. The final forecast is obtained by composing the forecasted results of each subseries. This proposed method is examined on Spanish and PJM electricity markets and compared with some other forecasting methods. (author)

  19. Improving Portfolio Optimization by DCC And DECO GARCH: Evidence from Istanbul Stock Exchange

    OpenAIRE

    Yilmaz, Tolgahan

    2010-01-01

    In this paper, the performance of global minimum variance (GMV) portfolios constructed by DCC and DECO-GARCH are compared to that of GMV portfolios constructed by sample covariance and constant correlation methods in terms of reduced volatility. Also, the performance of GMV portfolios are tested against that of equally weighted and cap weighted portfolios. Portfolios are constructed from the stocks listed in Istanbul Stock Exchange 30 index (hereafter, ISE-30). The results show that GMV portf...

  20. Improving Portfolio Optimization by DCC And DECO GARCH: Evidence from Istanbul Stock Exchange

    OpenAIRE

    Yilmaz, Tolgahan

    2010-01-01

    In this paper, the performance of global minimum variance (GMV) portfolios constructed by DCC and DECO-GARCH are compared to that of GMV portfolios constructed by sample covariance and constant correlation methods in terms of reduced volatility. Also, the performance of GMV portfolios are tested against that of equally weighted and cap weighted portfolios. Portfolios are constructed from the stocks listed in Istanbul Stock Exchange 30 index (hereafter, ISE-30). The results show that GMV portf...

  1. Estimation of value at risk in currency exchange rate portfolio using asymmetric GJR-GARCH Copula

    Science.gov (United States)

    Nurrahmat, Mohamad Husein; Noviyanti, Lienda; Bachrudin, Achmad

    2017-03-01

    In this study, we discuss the problem in measuring the risk in a portfolio based on value at risk (VaR) using asymmetric GJR-GARCH Copula. The approach based on the consideration that the assumption of normality over time for the return can not be fulfilled, and there is non-linear correlation for dependent model structure among the variables that lead to the estimated VaR be inaccurate. Moreover, the leverage effect also causes the asymmetric effect of dynamic variance and shows the weakness of the GARCH models due to its symmetrical effect on conditional variance. Asymmetric GJR-GARCH models are used to filter the margins while the Copulas are used to link them together into a multivariate distribution. Then, we use copulas to construct flexible multivariate distributions with different marginal and dependence structure, which is led to portfolio joint distribution does not depend on the assumptions of normality and linear correlation. VaR obtained by the analysis with confidence level 95% is 0.005586. This VaR derived from the best Copula model, t-student Copula with marginal distribution of t distribution.

  2. PERHITUNGAN NILAI BETA DARI BEBERAPA SAHAM UNGGULAN DI INDONESIA DENGAN MENGGUNAKAN METODE GARCH

    Directory of Open Access Journals (Sweden)

    NI KADEK PUSPITAYANTI

    2016-05-01

    Full Text Available The objective of investment in the capital market is to acquire dividends and capital gain. The fact proves that the advantage of investation risky assets is uncertain . This is because of the difficulty in analyzing and predicting Return and stock losses due to factors that affect the movement of the stock price , such as economic factors , political , social , and security. The model can be used by investors in predicting stock returns expected that Generalized Autoregressive Conditional Heteroscedaticity (GARCH. In this study calculations beta value of some leading stocks in Indonesia by using Generalized Autoregressive Conditional Heteroscedaticity (GARCH are presented . The data used this search is secondary data covering daily data sampled 5 shares of PT Unilever Indonesia Tbk , PT Indosat Tbk , PT Indofood Sukses Makmur Tbk , PT Telkom Indonesia Tbk , PT Holcim Indonesia Tbk. From the results described fifth beta value of these shares using the method GARCH beta greater than the market in the period from 23 September 2013 until 24 September 2014.

  3. Uncertainty analysis of hydrological processes based on ARMA——GARCH model

    Institute of Scientific and Technical Information of China (English)

    WANG HongRui; GAO Xiong; QIAN LongXia; YU Song

    2012-01-01

    Uncertainty analysis and risk analysis are two important areas of modern water resource management,in which accurate variance estimation is required.The traditional runoff model is established under the assumption that the variance is a constant or it changes with the seasons.However,hydrological processes in the real world are often heteroscedastic,which can be tested by McLeod-Li test and Engle Lagrange multiplier test.In such cases,the GARCH model of hydrological processes is established in this article.First,the seasonal factors in the sequence are removed.Second,the traditional ARMA model is established.Then,the GARCH model is used to correct the residual.At last,the daily runoff data in 1949 2001 of Yichang Hydrological Station is taken to be an example.The result shows that compared to the traditional ARMA model,the GARCH model has the ability to predict more accurate confidence intervals under the same confidence level.

  4. Model ARIMAX Dan Deteksi GARCH Untuk Peramalan Inflasi Kota Denpasar Tahun 2014

    Directory of Open Access Journals (Sweden)

    Rukini Rukini

    2015-11-01

    Full Text Available Inflation is an important indicator that can provide information on the development of prices of goods and services consumed by public. Forecasting inflation is important in order to assist the government in taking monetary policy to maintain economic stability in the future. In general, forecasting inflation can be done with time series approach, causal approach, and a combination of time series and causal approaches. Models with a combined approach that is widely used for forecasting inflation is ARIMAX model that includes Transfer Function and Intervention Model or also known as dynamic regression models. In addition, Generalized Autoregresive Conditional Heteroscedasticity (GARCH for variance has also been applied to models in forecasting inflation. This study explains the procedure of building the ARIMAX models and GARCH detection using a case study of inflation data in denpasar city. Predictor variables  consist of metric data variable (ie number of foreign tourists and non-metric data variables (the increase of fuel oil (BBM , basic electricity tariff (TDL and  Bali bombings. The best model for in-sample data is intervention model with the smallest value of AIC and SBC, whereas the best model for data out-sample is  transfer function model with the smallest RMSE value. GARCH detection results with Langrange Multiplier test shows no evidence of heteroscedasticity in  ARIMAX model.

  5. Regularidades probabilísticas de las series financieras y la familia de modelos GARCH

    Directory of Open Access Journals (Sweden)

    Armando Sánchez Vargas

    2006-01-01

    Full Text Available Este artículo tiene como objetivo discutir brevemente acerca de algunos modelos de volatilidad de la familia GARCH. Nuestro trabajo enfatiza el papel que han jugado las regularidades empíricas (‘hechos estilizados’ en el desarrollo de nuevos y más complejos modelos de volatilidad. Se argumenta que los modelos GARCH han sido exitosos porque han permitido capturar regularidades empíricas como la dependencia de segundo orden (Volatility Clustering y las colas pesadas (Thick Tails que caracterizan a las series de los retornos financieros. Sin embargo, se concluye que existe una gran veta para investigación sobre el tema de la modelación de la volatilidad, ya que la familia GARCH enfrenta varios problemas para capturar otras regularidades probabilísticas tales como la leptokurtosis de los datos, asimismo presentan problemas de especificación y estimación parsimoniosa de los parámetros.

  6. Advanced Curation For Current and Future Extraterrestrial Sample Collections Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a planned three-year project to develop  extraterrestrial sample curation techniques and equipment to prepare for future human and robotic sample return...

  7. The Search for Extraterrestrial Intelligence: Fact, not Fiction

    Energy Technology Data Exchange (ETDEWEB)

    Tarter, Jill (SETI Institute, Director)

    2009-03-11

    Jill Tarter, director of the Center for SETI (Search for Extraterrestrial Intelligence) Research, will discuss the new Allen Telescope Array being developed for SETI that will provide the first systematic look at the transient radio universe.

  8. The Development of Politics in Extraterrestrial Colonies

    Science.gov (United States)

    Sivier, D. J.

    The existence of feudal or totalitarian interplanetary empires has been a favourite theme in Science Fiction. Although the vast distances between the stars make the emergence of an interstellar empire impossible without the creation of a faster than light drive, this is not necessarily true for the other worlds within our solar system. Environmental constraints on the off-world colonies themselves, and repressive, hierarchical and feudalistic social and commercial institutions and customs inherited from the parent cultures on Earth and a tradition of military rule descending from the foundation of these colonies may all work to bring about a new feudal or totalitarian social order on humanity's extraterrestrial colonies. There are encouraging signs that this may not be the case, however. Already the debate over the projected colonisation of Mars is a factor influencing present controversies over repressive institutions and customs. Nevertheless, those wishing for a free, democratic, and politically, socially and technologically innovative and vigorous human society spreading throughout the solar system should not become complacent.

  9. GARCH(1,1)模型及其在汇率条件波动预测中的应用%GARCH(1,1) Model and Its Application in Forecasting Conditional Volatility of Exchange Rate

    Institute of Scientific and Technical Information of China (English)

    苏岩; 杨振海

    2007-01-01

    检验人民币/日元汇率与波动的时间序列特征,证实存在简单单位根过程及条件异方差性.计算表明,其汇率变化率的ARMA及ARMA/GARCH组合模型的建模不成立,GARCH、EGARCH、 IGARCH模型的建模效果接近,且GARCH(1,1)拟合效果最好.GARCH(1,1)模型的跨度为一年的样本外条件异方差预测,显示出该年末汇率的震荡,与实际情况一致.GARCH(1,1)是汇率数据建娱的首选模型.

  10. GARCH-neural network model for forecasting the volatility of bid-ask spread of the Chinese stock market%GARCH-neural网络模型对股票价格买卖差波动率的预测

    Institute of Scientific and Technical Information of China (English)

    母泽平; 李思明

    2015-01-01

    股票价格买卖差是衡量金融市场流动性和有效性的重要指标,已经得到学术界的广泛研究.相比而言,作为衡量股票市场风险的重要因素的股票价格买卖价差的波动率却没有得到相同的重视.在广义自回归条件异方差(generalized autoregressive conditional heteroscedasticity,GARCH)模型的基础上,提出了GARCH-neural network (GARCH-NN)混合模型分析股票价格买卖价差波动率的动态性.以深圳证券交易所成分股价指数的高频数据为样本对所提模型进行了实证分析.运用GARCH家族模型对股票价格买卖差波动率的动态性进行分析,得出预测效果最优的GARCH模型.在最优GARCH模型的基础上结合神经网络分析方法即GARCH-NN混合模型对样本数据进行了实证分析.比较分析最优GARCH模型和GARCH-NN混合模型对股票价格买卖差波动率的预测效果,并以AIC(Akaike information criterion)和BIC(Bayesian information criterion)作为检验模型预测效果的指标.实证结果表明,提出的GARCH-NN混合模型更优.

  11. Drilling Systems for Extraterrestrial Subsurface Exploration

    Science.gov (United States)

    Zacny, K.; Bar-Cohen, Y.; Brennan, M.; Briggs, G.; Cooper, G.; Davis, K.; Dolgin, B.; Glaser, D.; Glass, B.; Gorevan, S.; Guerrero, J.; McKay, C.; Paulsen, G.; Stanley, S.; Stoker, C.

    2008-06-01

    Drilling consists of 2 processes: breaking the formation with a bit and removing the drilled cuttings. In rotary drilling, rotational speed and weight on bit are used to control drilling, and the optimization of these parameters can markedly improve drilling performance. Although fluids are used for cuttings removal in terrestrial drilling, most planetary drilling systems conduct dry drilling with an auger. Chip removal via water-ice sublimation (when excavating water-ice bound formations at pressure below the triple point of water) and pneumatic systems are also possible. Pneumatic systems use the gas or vaporization products of a high-density liquid brought from Earth, gas provided by an in situ compressor, or combustion products of a monopropellant. Drill bits can be divided into coring bits, which excavate an annular shaped hole, and full-faced bits. While cylindrical cores are generally superior as scientific samples, and coring drills have better performance characteristics, full-faced bits are simpler systems because the handling of a core requires a very complex robotic mechanism. The greatest constraints to extraterrestrial drilling are (1) the extreme environmental conditions, such as temperature, dust, and pressure; (2) the light-time communications delay, which necessitates highly autonomous systems; and (3) the mission and science constraints, such as mass and power budgets and the types of drilled samples needed for scientific analysis. A classification scheme based on drilling depth is proposed. Each of the 4 depth categories (surface drills, 1-meter class drills, 10-meter class drills, and deep drills) has distinct technological profiles and scientific ramifications.

  12. The Scientific Search for Extraterrestrial Intelligence: a Sociological Analysis.

    Science.gov (United States)

    Romesberg, Daniel Ray

    1992-01-01

    This study examines the search for extraterrestrial intelligence, as it has been conducted by scientists over the past century. The following questions are explored: (1) What are the historical patterns of American scientific interest in extraterrestrial intelligence? From a sociology of science perspective, how can these patterns of interest be explained? (2) Who are the most prominent scientists involved in SETI? What are their academic backgrounds? (3) How has the rather exotic idea of extraterrestrial intelligence managed to penetrate the realm of respectable science?. In order to measure the historical fluctuations of scientific interest in extraterrestrial intelligence, a frequency distribution of relevant articles published in American scientific journals over the past century has been constructed. The core scholars of the "extraterrestrial" field have been determined via citation analysis, in a selected portion of the scientific literature. An analysis of recent scientific literature on the Search for Extraterrestrial Intelligence (SETI) has revealed a number of tactics of legitimation and de-legitimation used by SETI proponents, as well as opponents. This study has generated the following findings: (1) Historically, there are three factors which tend to stimulate general scientific interest in extraterrestrial intelligence: First, the strong demonstration of the plausibility of extraterrestrial intelligence, or life, especially in a tangible, and therefore studiable location. Scientific laboratories are primary agents of plausibility here. Second, the organized political activity of SETI scientists. Third, the availability of government funding for searches for extraterrestrial intelligence, or life. (2) Statistically, the leading scholars of modern SETI are Sagan, Drake and Morrison. The field itself tends to be dominated by astronomers and physicists. (3) Because SETI has no concrete data, and is easily stigmatized as an illegitimate scientific activity

  13. Astrobo: Towards a new observatory control system for the Garching Observatory 0.6m

    Science.gov (United States)

    Schweyer, T.; Jarmatz, P.; Burwitz, V.

    2016-12-01

    The recently installed Campus Observatory Garching (COG) 0.6m telescope features a wide array of instruments, including a wide-field imager and a variety of spectrographs. To support all these different instruments and improve time usage, it was decided to develop a new control system from scratch, that will be able to safely observe autonomously as well as manually (for student lab courses). It is built using an hierarchical microservice architecture, which allows well-specified communication between its components regardless of the programming language used. This modular design allows for fast prototyping of components as well as easy implementation of complex instrumentation control software.

  14. Modeling inflation rates and exchange rates in Ghana: application of multivariate GARCH models

    OpenAIRE

    Nortey, Ezekiel NN; Ngoh, Delali D; Doku-Amponsah, Kwabena; Ofori-Boateng, Kenneth

    2015-01-01

    This paper was aimed at investigating the volatility and conditional relationship among inflation rates, exchange rates and interest rates as well as to construct a model using multivariate GARCH DCC and BEKK models using Ghana data from January 1990 to December 2013. The study revealed that the cumulative depreciation of the cedi to the US dollar from 1990 to 2013 is 7,010.2% and the yearly weighted depreciation of the cedi to the US dollar for the period is 20.4%. There was evidence that, t...

  15. Portfolio Risk Analysis using ARCH and GARCH Models in the Context of the Global Financial Crisis

    Directory of Open Access Journals (Sweden)

    Oana Mădălina PREDESCU

    2011-02-01

    Full Text Available This paper examines both the benefits of choosing an internationally diversified portfolio and the evolution of the portfolio risk in the context of the current global financial crisis. The portfolio is comprised of three benchmark indexes from Romania, UK and USA. Study results show that on the background of a global economic climate eroded strongly by the effects of the current financial crisis, international diversification does not reduce risk. Moreover, using ARCH and GARCH models shows that the evolution of portfolio volatility is influenced by the effects of the current global financial crisis.

  16. Modeling inflation rates and exchange rates in Ghana: application of multivariate GARCH models

    OpenAIRE

    Nortey, Ezekiel NN; Ngoh, Delali D; Doku-Amponsah, Kwabena; Ofori-Boateng, Kenneth

    2015-01-01

    This paper was aimed at investigating the volatility and conditional relationship among inflation rates, exchange rates and interest rates as well as to construct a model using multivariate GARCH DCC and BEKK models using Ghana data from January 1990 to December 2013. The study revealed that the cumulative depreciation of the cedi to the US dollar from 1990 to 2013 is 7,010.2% and the yearly weighted depreciation of the cedi to the US dollar for the period is 20.4%. There was evidence that, t...

  17. American Option Pricing using GARCH models and the Normal Inverse Gaussian distribution

    DEFF Research Database (Denmark)

    Stentoft, Lars Peter

    In this paper we propose a feasible way to price American options in a model with time varying volatility and conditional skewness and leptokurtosis using GARCH processes and the Normal Inverse Gaussian distribution. We show how the risk neutral dynamics can be obtained in this model, we interpret...... the effect of the riskneutralization, and we derive approximation procedures which allow for a computationally efficient implementation of the model. When the model is estimated on financial returns data the results indicate that compared to the Gaussian case the extension is important. A study of the model...

  18. Global Risk Evolution and Diversification: a Copula-DCC-GARCH Model Approach

    Directory of Open Access Journals (Sweden)

    Marcelo Brutti Righi

    2012-12-01

    Full Text Available In this paper we estimate a dynamic portfolio composed by the U.S., German, British, Brazilian, Hong Kong and Australian markets, the period considered started on September 2001 and finished in September 2011. We ran the Copula-DCC-GARCH model on the daily returns conditional covariance matrix. The results allow us to conclude that there were changes in portfolio composition, occasioned by modifications in volatility and dependence between markets. The dynamic approach significantly reduced the portfolio risk if compared to the traditional static approach, especially in turbulent periods. Furthermore, we verified that the estimated copula model outperformed the conventional DCC model for the sample studied.

  19. Do We Really Need Both BEKK and DCC? A Tale of Two Multivariate GARCH Models

    OpenAIRE

    Caporin, Massimiliano; McAleer, Michael

    2010-01-01

    textabstractThe management and monitoring of very large portfolios of financial assets are routine for many individuals and organizations. The two most widely used models of conditional covariances and correlations in the class of multivariate GARCH models are BEKK and DCC. It is well known that BEKK suffers from the archetypal “curse of dimensionality”, whereas DCC does not. It is argued in this paper that this is a misleading interpretation of the suitability of the two models for use in pr...

  20. Volatility in crude oil futures. A comparison of the predictive ability of GARCH and implied volatility models

    Energy Technology Data Exchange (ETDEWEB)

    Agnolucci, Paolo [University of Cambridge, Department of Land Economy, Cambridge Centre for Climate Change Mitigation Research (4CMR), 19 Silver Street, Cambridge CB3 9EP (United Kingdom)

    2009-03-15

    The WTI future contract quoted at the NYMEX is the most actively traded instrument in the energy sector. This paper compares the predictive ability of two approaches which can be used to forecast volatility: GARCH-type models where forecasts are obtained after estimating time series models, and an implied volatility model where forecasts are obtained by inverting one of the models used to price options. Although the main scope of the research discussed here is to evaluate which model produces the best forecast of volatility for the WTI future contract, evaluated according to statistical and regression-based criteria, we also investigate whether volatility of the oil futures are affected by asymmetric effects, whether parameters of the GARCH models are influenced by the distribution of the errors and whether allowing for a time-varying long-run mean in the volatility produces any improvement on the forecast obtained from GARCH models. (author)

  1. ACD-GARCH model and its application to Chinese stock market%中国证券市场的ACD-GARCH模型及其应用

    Institute of Scientific and Technical Information of China (English)

    陈敏; 王国明; 吴国富; 蒋学雷

    2003-01-01

    This paper uses a new statistical model (ACD-GARCH) to analysis the high-frequency data which arrive at irregular intervals in China stock market. We use the ACD-GARCH model to analysis the relation among the transactions duration and the returns and variances for the index of Shanghai and Shenzhen stock market.

  2. Global self-weighted and local quasi-maximum exponential likelihood estimators for ARMA--GARCH/IGARCH models

    CERN Document Server

    Zhu, Ke; 10.1214/11-AOS895

    2012-01-01

    This paper investigates the asymptotic theory of the quasi-maximum exponential likelihood estimators (QMELE) for ARMA--GARCH models. Under only a fractional moment condition, the strong consistency and the asymptotic normality of the global self-weighted QMELE are obtained. Based on this self-weighted QMELE, the local QMELE is showed to be asymptotically normal for the ARMA model with GARCH (finite variance) and IGARCH errors. A formal comparison of two estimators is given for some cases. A simulation study is carried out to assess the performance of these estimators, and a real example on the world crude oil price is given.

  3. Science, religion, and the search for extraterrestrial intelligence

    CERN Document Server

    Wilkinson, David

    2013-01-01

    If the discovery of life elsewhere in the universe is just around the corner, what would be the consequences for religion? Would it represent another major conflict between science and religion, even leading to the death of faith? Some would suggest that the discovery of any suggestion of extraterrestrial life would have a greater impact than even the Copernican and Darwinian revolutions. It is now over 50 years since the first modern scientific papers were published on the search for extraterrestrial intelligence (SETI). Yet the religious implications of this search and possible discovery have never been systematically addressed in the scientific or theological arena. SETI is now entering its most important era of scientific development. New observation techniques are leading to the discovery of extra-solar planets daily, and the Kepler mission has already collected over 1000 planetary candidates. This deluge of data is transforming the scientific and popular view of the existence of extraterrestrial intel...

  4. Characterizing Amorphous Silicates in Extraterrestrial Materials

    Science.gov (United States)

    Fu, X.; Wang, A.; Krawczynski, M. J.

    2015-12-01

    Amorphous silicates are common in extraterrestrial materials. They are seen in the matrix of carbonaceous chondrites as well as in planetary materials. Tagish Lake is one of the most primitive carbonaceous meteorites in which TEM and XRD analyses found evidence for poorly crystalline phyllosilicate-like species; Raman spectra revealed amorphous silicates with variable degree of polymerization and low crystallinity. On Mars, CheMin discovered amorphous phases in all analyzed samples, and poorly crystalline smectite in mudstone samples. These discoveries pose questions on the crystallinity of phyllosilicates found by remote sensing on Mars, which is directly relevant to aqueous alteration during geologic history of Mars. Our goal is to use spectroscopy to better characterize amorphous silicates. We use three approaches: (1) using silicate glasses synthesized with controlled chemistry to study the effects of silicate polymerization and (2) using phyllosilicates synthesized with controlled hydrothermal treatment to study the effect of crystallinity on vibrational spectroscopy, finally (3) to use the developed correlations in above two steps to study amorphous phases in meteorites, and those found in future missions to Mars. In the 1st step, silicate glasses were synthesized from pure oxides in a range of NBO/T ratios (from 0 to 4). Depending on the targeted NBO/T and composition of mixed oxides, temperatures for each experiment fell in a range from 1260 to 1520 °C, run for ~ 4 hrs. The melt was quenched in liquid N2 or water. Homogeneity of glass was checked under optical microscopy. Raman spectra were taken over 100 spots on small chips free of bubbles and crystals. We have observed that accompanying an increase of NBO/T, there is a strengthening and a position shift of the Raman peak near 1000 cm-1 (Si-Onon-bridging stretching mode), and the weakening of broad Raman peaks near 500 cm-1 (ring breathing mode) and 700cm-1 (Si-Obridging-Si mode). We are building the

  5. Estimating Risk of Natural Gas Portfolios by Using GARCH-EVT-Copula Model

    Science.gov (United States)

    Tang, Jiechen; Zhou, Chao; Yuan, Xinyu; Sriboonchitta, Songsak

    2015-01-01

    This paper concentrates on estimating the risk of Title Transfer Facility (TTF) Hub natural gas portfolios by using the GARCH-EVT-copula model. We first use the univariate ARMA-GARCH model to model each natural gas return series. Second, the extreme value distribution (EVT) is fitted to the tails of the residuals to model marginal residual distributions. Third, multivariate Gaussian copula and Student t-copula are employed to describe the natural gas portfolio risk dependence structure. Finally, we simulate N portfolios and estimate value at risk (VaR) and conditional value at risk (CVaR). Our empirical results show that, for an equally weighted portfolio of five natural gases, the VaR and CVaR values obtained from the Student t-copula are larger than those obtained from the Gaussian copula. Moreover, when minimizing the portfolio risk, the optimal natural gas portfolio weights are found to be similar across the multivariate Gaussian copula and Student t-copula and different confidence levels. PMID:26351652

  6. Estimating Risk of Natural Gas Portfolios by Using GARCH-EVT-Copula Model.

    Science.gov (United States)

    Tang, Jiechen; Zhou, Chao; Yuan, Xinyu; Sriboonchitta, Songsak

    2015-01-01

    This paper concentrates on estimating the risk of Title Transfer Facility (TTF) Hub natural gas portfolios by using the GARCH-EVT-copula model. We first use the univariate ARMA-GARCH model to model each natural gas return series. Second, the extreme value distribution (EVT) is fitted to the tails of the residuals to model marginal residual distributions. Third, multivariate Gaussian copula and Student t-copula are employed to describe the natural gas portfolio risk dependence structure. Finally, we simulate N portfolios and estimate value at risk (VaR) and conditional value at risk (CVaR). Our empirical results show that, for an equally weighted portfolio of five natural gases, the VaR and CVaR values obtained from the Student t-copula are larger than those obtained from the Gaussian copula. Moreover, when minimizing the portfolio risk, the optimal natural gas portfolio weights are found to be similar across the multivariate Gaussian copula and Student t-copula and different confidence levels.

  7. Forecasting volatility in gold returns under the GARCH, IGARCH and FIGARCH frameworks: New evidence

    Science.gov (United States)

    Bentes, Sonia R.

    2015-11-01

    This study employs three volatility models of the GARCH family to examine the volatility behavior of gold returns. Much of the literature on this topic suggests that gold plays a fundamental role as a hedge and safe haven against adverse market conditions, which is particularly relevant in periods of high volatility. This makes understanding gold volatility important for a number of theoretical and empirical applications, namely investment valuation, portfolio selection, risk management, monetary policy-making, futures and option pricing, hedging strategies and value-at-risk (VaR) policies (e.g. Baur and Lucey (2010)). We use daily data from August 2, 1976 to February 6, 2015 and divide the full sample into two periods: the in-sample period (August 2, 1976-October 24, 2008) is used to estimate model coefficients, while the out-of-sample period (October 27, 2008-February 6, 2015) is for forecasting purposes. Specifically, we employ the GARCH(1,1), IGARCH(1,1) and FIGARCH(1, d,1) specifications. The results show that the FIGARCH(1, d,1) is the best model to capture linear dependence in the conditional variance of the gold returns as given by the information criteria. It is also found to be the best model to forecast the volatility of gold returns.

  8. Estimating Risk of Natural Gas Portfolios by Using GARCH-EVT-Copula Model

    Directory of Open Access Journals (Sweden)

    Jiechen Tang

    2015-01-01

    Full Text Available This paper concentrates on estimating the risk of Title Transfer Facility (TTF Hub natural gas portfolios by using the GARCH-EVT-copula model. We first use the univariate ARMA-GARCH model to model each natural gas return series. Second, the extreme value distribution (EVT is fitted to the tails of the residuals to model marginal residual distributions. Third, multivariate Gaussian copula and Student t-copula are employed to describe the natural gas portfolio risk dependence structure. Finally, we simulate N portfolios and estimate value at risk (VaR and conditional value at risk (CVaR. Our empirical results show that, for an equally weighted portfolio of five natural gases, the VaR and CVaR values obtained from the Student t-copula are larger than those obtained from the Gaussian copula. Moreover, when minimizing the portfolio risk, the optimal natural gas portfolio weights are found to be similar across the multivariate Gaussian copula and Student t-copula and different confidence levels.

  9. Modeling and forecasting the volatility of Islamic unit trust in Malaysia using GARCH model

    Science.gov (United States)

    Ismail, Nuraini; Ismail, Mohd Tahir; Karim, Samsul Ariffin Abdul; Hamzah, Firdaus Mohamad

    2015-10-01

    Due to the tremendous growth of Islamic unit trust in Malaysia since it was first introduced on 12th of January 1993 through the fund named Tabung Ittikal managed by Arab-Malaysian Securities, vast studies have been done to evaluate the performance of Islamic unit trust offered in Malaysia's capital market. Most of the studies found that one of the factors that affect the performance of the fund is the volatility level. Higher volatility produces better performance of the fund. Thus, we believe that a strategy must be set up by the fund managers in order for the fund to perform better. By using a series of net asset value (NAV) data of three different types of fund namely CIMB-IDEGF, CIMB-IBGF and CIMB-ISF from a fund management company named CIMB Principal Asset Management Berhad over a six years period from 1st January 2008 until 31st December 2013, we model and forecast the volatility of these Islamic unit trusts. The study found that the best fitting models for CIMB-IDEGF, CIMB-IBGF and CIMB-ISF are ARCH(4), GARCH(3,3) and GARCH(3,1) respectively. Meanwhile, the fund that is expected to be the least volatile is CIMB-IDEGF and the fund that is expected to be the most volatile is CIMB-IBGF.

  10. Modeling climate effects on hip fracture rate by the multivariate GARCH model in Montreal region, Canada

    Science.gov (United States)

    Modarres, Reza; Ouarda, Taha B. M. J.; Vanasse, Alain; Orzanco, Maria Gabriela; Gosselin, Pierre

    2014-07-01

    Changes in extreme meteorological variables and the demographic shift towards an older population have made it important to investigate the association of climate variables and hip fracture by advanced methods in order to determine the climate variables that most affect hip fracture incidence. The nonlinear autoregressive moving average with exogenous variable-generalized autoregressive conditional heteroscedasticity (ARMA X-GARCH) and multivariate GARCH (MGARCH) time series approaches were applied to investigate the nonlinear association between hip fracture rate in female and male patients aged 40-74 and 75+ years and climate variables in the period of 1993-2004, in Montreal, Canada. The models describe 50-56 % of daily variation in hip fracture rate and identify snow depth, air temperature, day length and air pressure as the influencing variables on the time-varying mean and variance of the hip fracture rate. The conditional covariance between climate variables and hip fracture rate is increasing exponentially, showing that the effect of climate variables on hip fracture rate is most acute when rates are high and climate conditions are at their worst. In Montreal, climate variables, particularly snow depth and air temperature, appear to be important predictors of hip fracture incidence. The association of climate variables and hip fracture does not seem to change linearly with time, but increases exponentially under harsh climate conditions. The results of this study can be used to provide an adaptive climate-related public health program and ti guide allocation of services for avoiding hip fracture risk.

  11. Study on Gold Investment Risk Measurement Based on the GARCH-EVT Model%基于GARCH-EVT模型的黄金投资风险度量研究

    Institute of Scientific and Technical Information of China (English)

    袁吉伟

    2012-01-01

    本文利用1975年1月2日至2012年7月27日国际黄金日收益率时间序列,研究黄金投资风险特征及GARCH-EVT模型刻画黄金投资风险的适用性。研究发现,黄金日收益率时间序列呈现高峰厚尾分布,具有显著的波动集群性。返回检验证明,利用GARCH-EVT模型计量出的黄金投资动态VAR通过Kupiec检验,能够较好的覆盖黄金投资实际损失,预测黄金投资风险的能力较高。%This article aims to study gold investment risk characteristics and GARCH-EVT model' s capability of measuring gold investment risk, using international gold daily return time series from January 2, 1975 to July 27, 2012. Study finds, gold daily return time series display high peak and thick tail distribution, and obvious volatility clustering. Back testing demonstrates that GARCH-EVT model can go through Kupiec test, and has high capacity to predict gold investment risk.

  12. Viable Bacteria in Antarctic Soils and - Two Models for Extraterrestrial Search of Life

    Science.gov (United States)

    Soina, Vera; Vorobyova, Elena; Lysak, Ludmila; Mergelov, Nikita

    Antarctic soils and permafrost are the most convenient models for search life preservation in extraterrestrial cryogenic environment. Study of life activity and preservation of prokaryotes in such extreme environment allow assuming, that those habitats must be viewed as two models for astrobiology extrapolations. Antarctic permafrost due to long term freezing can be regarded as the most stable environment for life preservation and expanding of potential physiological cell activity due to stabilization of cell structures and biomolecules. Antarctic soils seem to be not less attractive as a model for study of life on the surface of Antarctic rocks, but in contrast to permafrost are characterized by less stable external factors. Presumably, it is due to changing cycles of freezing and thawing and high doses of UV radiation, that make such biotopes more extreme for microbial survival. A combination of culture- depended and - independent techniques, including SEM and TEM methods were used to characterize bacteria community in earlier not investigated Antarctic soils in the oases of Larsemann Hills (East Antarctic Coast). Several important characteristics of Antarctic soil and permafrost bacteria as models for possible signs of life in extraterrestrial habitats are discussed (cytomorphological and physiological characteristics of bacteria both in situ, and cells isolated from permafrost and exposed to various external stress factors). Our data indicate that significant discrepancy between indexes of total and viable number of cells and irregularity of such indexes in horizons of developing soils and permafrost sediments can be explained by specification of physical and chemical processes in those habitats. Also, in Antarctic and extraterrestrial investigations is important to take into account the leading role of microbial biofilms, where microorganisms are intimately associated with each other and mineral particles through binding and inclusion within exopolymer matrix

  13. Empirical Results of Modeling EUR/RON Exchange Rate using ARCH, GARCH, EGARCH, TARCH and PARCH models

    Directory of Open Access Journals (Sweden)

    Andreea – Cristina PETRICĂ

    2017-03-01

    Full Text Available The aim of this study consists in examining the changes in the volatility of daily returns of EUR/RON exchange rate using on the one hand symmetric GARCH models (ARCH and GARCH and on the other hand the asymmetric GARCH models (EGARCH, TARCH and PARCH, since the conditional variance is time-varying. The analysis takes into account daily quotations of EUR/RON exchange rate over the period of 04th January 1999 to 13th June 2016. Thus, we are modeling heteroscedasticity by applying different specifications of GARCH models followed by looking for significant parameters and low information criteria (minimum Akaike Information Criterion. All models are estimated using the maximum likelihood method under the assumption of several distributions of the innovation terms such as: Normal (Gaussian distribution, Student’s t distribution, Generalized Error distribution (GED, Student’s with fixed df. Distribution, and GED with fixed parameter distribution. The predominant models turned out to be EGARCH and PARCH models, and the empirical results point out that the best model for estimating daily returns of EUR/RON exchange rate is EGARCH(2,1 with Asymmetric order 2 under the assumption of Student’s t distributed innovation terms. This can be explained by the fact that in case of EGARCH model, the restriction regarding the positivity of the conditional variance is automatically satisfied.

  14. A note on self-normalized Dickey-Fuller test for unit root in autoregressive time series with GARCH errors

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-rong; ZHANG Li-xin

    2008-01-01

    In this article, the unit root test for AR (p) model with GARCH errors is considered. The Dickey-Fuller test statistics are rewritten in the form of self-normalized sums, and the asymptotic distribution of the test statistics is derived under the weak conditions.

  15. Confidence intervals for ARMA-GARCH Value-at-Risk : The case of heavy tails and skewness

    NARCIS (Netherlands)

    Spierdijk, Laura

    2016-01-01

    It is a well-known result that, when the ARMA GARCH model errors lack a finite fourth moment, the asymptotic distribution of the quasi-maximum likelihood estimator may not be Normal. In such a scenario the conventional bootstrap turns out inconsistent. Surprisingly, simulations show that the convent

  16. Confidence intervals for ARMA-GARCH Value-at-Risk : The case of heavy tails and skewness

    NARCIS (Netherlands)

    Spierdijk, Laura

    It is a well-known result that, when the ARMA GARCH model errors lack a finite fourth moment, the asymptotic distribution of the quasi-maximum likelihood estimator may not be Normal. In such a scenario the conventional bootstrap turns out inconsistent. Surprisingly, simulations show that the

  17. The Martian and extraterrestrial UV radiation environment. Part II: further considerations on materials and design criteria for artificial ecosystems.

    Science.gov (United States)

    Cockell, C S

    2001-12-01

    Ultraviolet radiation is an important natural physical influence on organism function and ecosystem interactions. The UV radiation fluxes in extraterrestrial environments are substantially different from those experienced on Earth. On Mars, the moon and in Earth orbit they are more biologically detrimental than on Earth. Based on previously presented fluxes and biologically weighted irradiances, this paper considers in more detail measures to mitigate UV radiation damage and methods to modify extraterrestrial UV radiation environments in artificial ecosystems that use natural sunlight. The transmission characteristics of a Martian material that will mimic the terrestrial UV radiation environment are presented. Transmissivity characteristics of other Martian and lunar materials are described. Manufacturing processes for the production of plastics and glass on the lunar and Martian surface are presented with special emphasis on photobiological requirements. Novel UV absorbing configurations are suggested.

  18. Assessing Efficiency of D-Vine Copula ARMA-GARCH Method in Value at Risk Forecasting: Evidence from PSE Listed Companies

    Directory of Open Access Journals (Sweden)

    Václav Klepáč

    2015-01-01

    Full Text Available The article points out the possibilities of using static D-Vine copula ARMA-GARCH model for estimation of 1 day ahead market Value at Risk. For the illustration we use data of the four companies listed on Prague Stock Exchange in range from 2010 to 2014. Vine copula approach allows us to construct high-dimensional copula from both elliptical and Archimedean bivariate copulas, i.e. multivariate probability distribution, created from process innovations. Due to a deeper shortage of existing domestic results or comparison studies with advanced volatility governed VaR forecasts we backtested D-Vine copula ARMA-GARCH model against the VaR rolling out of sample forecast from October 2012 to April 2014 of chosen benchmark models, e.g. multivariate VAR-GO-GARCH, VAR-DCC-GARCH and univariate ARMA-GARCH type models. Common backtesting via Kupiec and Christoffersen procedures offer generalization that technological superiority of model supports accuracy only in case of an univariate modeling – working with non-basic GARCH models and innovations with leptokurtic distributions. Multivariate VAR governed type models and static Copula Vines performed in stated backtesting comparison worse than selected univariate ARMA-GARCH, i.e. it have overestimated the level of actual market risk, probably due to hardly tractable time-varying dependence structure.

  19. Application of GARCH Model in Research on Price of Agricultural Products

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Taking the price of grain in Guizhou Province as an example, by establishing GARCH model, I calculate VAR of logarithm return of grain price index, in order to conduct research on the variation law of price of the agricultural products. The results show that VAR of grain in Guizhou has variation. After the year 2010, VAR value is gradually increasing, and the price variation risk of grain market tends to increase progressively. Based on the characteristics of grain price variation, a series of corresponding proposals are put forward to stabilize the grain price as follows: strengthen the agricultural infrastructure construction, and promote the agricultural overall production capacity; reinforce the market supervision on the circulation field of agricultural products, and maintain market order; improve regulation system of agricultural products, and stabilize the price of agricultural products; strengthen mobility regulation, and prevent a flood of speculative cash.

  20. Specification and testing of Multiplicative Time-Varying GARCH models with applications

    DEFF Research Database (Denmark)

    Amado, Cristina; Teräsvirta, Timo

    2017-01-01

    In this article, we develop a specification technique for building multiplicative time-varying GARCH models of Amado and Teräsvirta (2008, 2013). The variance is decomposed into an unconditional and a conditional component such that the unconditional variance component is allowed to evolve smoothly...... over time. This nonstationary component is defined as a linear combination of logistic transition functions with time as the transition variable. The appropriate number of transition functions is determined by a sequence of specification tests. For that purpose, a coherent modelling strategy based...... is illustrated in practice with two real examples: an empirical application to daily exchange rate returns and another one to daily coffee futures returns....

  1. Risk Forecasting of Karachi Stock Exchange: A Comparison of Classical and Bayesian GARCH Models

    Directory of Open Access Journals (Sweden)

    Farhat Iqbal

    2016-09-01

    Full Text Available This paper is concerned with the estimation, forecasting and evaluation of Value-at-Risk (VaR of Karachi Stock Exchange before and after the global financial crisis of 2008 using Bayesian method. The generalized autoregressive conditional heteroscedastic (GARCH models under the assumption of normal and heavy-tailed errors are used to forecast one-day-ahead risk estimates. Various measures and backtesting methods are employed to evaluate VaR forecasts. The observed number of VaR violations using Bayesian method is found close to the expected number of violations. The losses are also found smaller than the competing Maximum Likelihood method. The results showed that the Bayesian method produce accurate and reliable VaR forecasts and can be preferred over other methods. 

  2. Impact of global financial crisis on precious metals returns: An application of ARCH and GARCH methods

    Science.gov (United States)

    Ismail, Mohd Tahir; Abdullah, Nurul Ain; Abdul Karim, Samsul Ariffin

    2013-04-01

    This paper is focusing on seeing the resilient of precious metals returns in facing the global financial crisis and provides a new guide for the investors before making investment decisions on precious metals. Four types of precious metals returns which are the variables selected in this study. The precious metals are gold, silver, bronze and platinum. All the variables are transferred to natural logarithm (ln). Daily data over the period 2 January 1995 to 30 December 2011 is used. Unit root tests that involve Augmented Dickey-Fuller (ADF) and Kwiatkowski-Phillips-Schmidt-Shin (KPSS) tests have been employed in determining the stationarity of the variables. Autoregressive Conditional Heteroscedasticity (ARCH) and Generalized Autoregressive Conditional Heteroscedasticity (GARCH) methods have been applied in measuring the impact of global financial crisis on precious metals returns. The result shows that investing in platinum is less risky compared to the other precious metals because it is not influence by the crisis period.

  3. The new structure powder diffractometer at the FRM-II in Garching

    Science.gov (United States)

    Gilles, R.; Artus, G.; Saroun, J.; Boysen, H.; Fuess, H.

    2000-03-01

    SPODI, the structure powder diffractometer, will be installed on beamline SR 8 at the FRM-II in Garching. The instrument has been designed to achieve an ideal compromise of good resolution up to very high 2 θ (by using a monochromator take-off angle of 155°) and high flux with special emphasis on ‘good’ profile shapes and low background. To optimise the parameters of the optical components like coatings of neutron guides, monochromator and soller collimators, Monte Carlo simulations were carried out. To check the results of the simulation calculations two different independent programs (MCSTAS and RESTRAX) were applied. An option for using a small-angle neutron scattering (SANS) device will eventually be included to perform Bragg scattering, SANS and diffuse scattering simultaneously on the sample.

  4. Probabilistic forecasting of the solar irradiance with recursive ARMA and GARCH models

    DEFF Research Database (Denmark)

    David, M.; Ramahatana, F.; Trombe, Pierre-Julien;

    2016-01-01

    of the grid-connected storage systems. If numerous methods for forecasting the mean of the solar irradiance were recently developed, there are only few works dedicated to the evaluation of prediction intervals associated to these point forecasts. Time series of solar irradiance and more specifically of clear...... sky index show some similarities with that of financial time series. The aim of this paper is to assess the performances of a commonly used combination of two linear models (ARMA and GARCH) in econometrics in order to provide probabilistic forecasts of solar irradiance. In addition, a recursive...... estimation of the parameters of the models has been set up in order to provide a framework that can be applied easily in an operational context. A comprehensive testing procedure has been used to assess both point forecasts and probabilistic forecasts. Using only the past records of the solar irradiance...

  5. Determination of the Price Transmission Mechanism in Iran Dates Market (Application of BV GARCH Model

    Directory of Open Access Journals (Sweden)

    H. Sherafatmand

    2016-10-01

    transmission in dates market bivariate GARCH model was used. Developments of ARCH and GARCH models take into account the nature of the phenomenon Volatility in financial and prices error component regression equations. ARCH model was first introduced by Engle and augmented GARCH model was first introduced by Bollerslev. Due to Conditional variance Heteroscedasticity, ARCH and GARCH models are widely used but little attention has been to this interaction. For this purpose, bivariate GARCH models developed. This study determined the mechanism of price transmission in date's market, over the period 1361: 1-1391: 4 with Diagonal VECH Bivariate GARCH model. Results and Discussion: With the implementation of augmented Dickey-Fuller test, it was found that the time series producer price index and the consumer price index over the period 1361:1-1391:4 are stationary in first difference. In this study, also Hegy test used for stationary of variables. In this test the unit root hypothesis tested with different periods (for the monthly data used in this study up to 12 repetitions will examined. Next, Johansen co-integration test results showed that there was a long-term relationship between the producer price index and the consumer price index. Granger causality test results indicated that there was a one-way causal relationship from consumer price index to producer price index. The results of this study indicated that the producer price index volatility with one lag has a positive and significant impact on its current volatility. As the results indicated, the covariance coefficient is statistically significant, indicating the volatility spillover between the two levels of the market. The spillover of volatility indicated uncertainty in the retail market and in producers market. The results also indicated that a one unit increase in the consumer price index cause an increase in producer price index less than unity (0.003. Conclusions: the price transmission in Dates market is incomplete

  6. Dynamic risk measure of securities investment fund via GARCH-EVT model%基于 GARCH-EVT 模型的证券投资基金动态风险测度

    Institute of Scientific and Technical Information of China (English)

    许启发; 陈士俊; 蒋翠侠

    2015-01-01

    Considering a class of financial assets which have more obvious extreme risk characteristics ,and tak-ing equity fund ,hybrid fund and bond fund as research subjects ,the performance of dynamic extreme risk measure estimated by RiskMetrics model ,GARCH model and GARCH-EVT model are comparatively stud-ied ,and the likelihood ratio test and Bootstrap method are used to backtest dynamic VaR risk measure and ES risk measure estimated by three models respectively .The empirical results show that the results of dynamic VaR risk measure and ES risk measure of each fund estimated by GARCH-EVT model are more accurate , which implies that extreme risk may be measured through the integration of GARCH model and extreme value theory ;ES risk measure is more conservative than VaR risk measure and should be used as a supplement to VaR risk measure when measuring the extreme risk .%文章考虑了一类极值风险特征更为明显的金融资产,以股票基金、混合基金和债券基金为研究对象,比较研究了RiskMetrics、GARCH和GARCH-EVT 3类模型在动态极端风险测度上的表现,分别采用似然比检验和Bootstrap方法对3类模型给出的VaR和ES动态风险测度效果进行了返回测试。实证研究表明:基于GARCH-EVT模型给出的各类基金动态VaR和ES风险测度结果更为准确,意味着将GARCH模型与极值理论相结合,能够实现极端风险的准确测度;ES风险测度比VaR风险测度更保守,在测度极端风险时,应采用ES风险测度作为VaR风险测度的补充。

  7. Comparison of forecasting performance between MODWT-GARCH(1,1 and MODWT-EGARCH(1,1 models: Evidence from African stock markets

    Directory of Open Access Journals (Sweden)

    Mohd Tahir Ismail

    2016-12-01

    Full Text Available Many researchers documented that if stock markets' returns series are significantly skewed, linear-GARCH(1,1 grossly underestimates the forecast values of the returns. However, this study showed that the linear Maximal Overlap Discreet Wavelet Transform MODWT-GARCH(1,1 actually gives an accurate forecast value of the returns. The study used the daily returns of four African countries' stock market indices for the period January 2, 2000, to December 31, 2014. The Maximal Overlap Discreet Wavelet Transform-GARCH(1,1 model and the Maximal Overlap Discreet Wavelet Transform-EGARCH(1,1 model are exhaustively compared. The results show that although both models fit the returns data well, the forecast produced by the Maximal Overlap Discreet Wavelet Transform-EGARCH(1,1 model actually underestimates the observed returns whereas the Maximal Overlap Discreet Wavelet Transform-GARCH(1,1 model generates an accurate forecast value of the observed returns.

  8. 基于GARCH-EVT模型的黄金投资风险度量研究%Gold Investment Risk Measurement Study Based on the GARCH-EVT Model

    Institute of Scientific and Technical Information of China (English)

    袁吉伟

    2012-01-01

    本文利用1975年1月2日至2012年7月27日国际黄金市场日收益率时间序列,研究黄金投资的风险特征,以及利用GARCH-EVT模型刻画黄金投资风险的适用性.研究发现,黄金投资日收益率时间序列呈高峰厚尾分布,具有显著的波动集群性.返回检验证明,利用GARCH-EVT模型计量出的黄金投资动态VaR通过Kupiec检验,能够较好地覆盖黄金投资的实际损失,预测黄金投资风险的能力较高.

  9. Philosophical issues in the search for extraterrestrial life and intelligence

    Science.gov (United States)

    Schneider, Jean

    2013-07-01

    In the search for extraterrestrial life and intelligence, it is essential to clarify what is to be meant by `life' and `intelligence'. I first analyse what it means to `define' these words. I will show that some philosophical prejudice is unavoidable. As a working hypothesis, I consider two types of philosophy: `natural philosophy', seeking for some essence of things, and `critical (or analytical) philosophy', devoted to the analysis of the procedures by which we claim to construct a reality. An extension of critical philosophy, epistemo-analysis (i.e. the psycho-analysis of concepts) is presented and applied to the definition of exolife and to extraterrestrial `intelligence'. Some pragmatic conclusions are finally drawn for future search strategies.

  10. Extrasolar Asteroid Mining as Forensic Evidence for Extraterrestrial Intelligence

    OpenAIRE

    Forgan, Duncan; Elvis, Martin

    2011-01-01

    The development of civilisations like ours into spacefaring, multi-planet entities requires significant raw materials to construct vehicles and habitats. Interplanetary debris, including asteroids and comets, may provide such a source of raw materials. In this article we present the hypothesis that extraterrestrial intelligences (ETIs) engaged in asteroid mining may be detectable from Earth. Considering the detected disc of debris around Vega as a template, we explore the observational signat...

  11. HYDROGEN-OXYGEN PRIMARY EXTRATERRESTRIAL (HOPE) FUEL CELL PROGRAM

    Science.gov (United States)

    The HOPE (Hydrogen-Oxygen Primary Extraterrestrial) Fuel Cell Program is a multi-phase effort to advance the state-of-the-art of fuel cells by...configuration fuel cell module. The HOPE spacecraft, fuel supply tanks, pneumatics, and thermal systems were designed and fabricated to provide...verify water removal, thermal design, and 30-day shelf-life of the fuel cell . The 35-cell module was subjected to a series of performance tests

  12. Information theory, animal communication, and the search for extraterrestrial intelligence

    Science.gov (United States)

    Doyle, Laurance R.; McCowan, Brenda; Johnston, Simon; Hanser, Sean F.

    2011-02-01

    We present ongoing research in the application of information theory to animal communication systems with the goal of developing additional detectors and estimators for possible extraterrestrial intelligent signals. Regardless of the species, for intelligence (i.e., complex knowledge) to be transmitted certain rules of information theory must still be obeyed. We demonstrate some preliminary results of applying information theory to socially complex marine mammal species (bottlenose dolphins and humpback whales) as well as arboreal squirrel monkeys, because they almost exclusively rely on vocal signals for their communications, producing signals which can be readily characterized by signal analysis. Metrics such as Zipf's Law and higher-order information-entropic structure are emerging as indicators of the communicative complexity characteristic of an "intelligent message" content within these animals' signals, perhaps not surprising given these species' social complexity. In addition to human languages, for comparison we also apply these metrics to pulsar signals—perhaps (arguably) the most "organized" of stellar systems—as an example of astrophysical systems that would have to be distinguished from an extraterrestrial intelligence message by such information theoretic filters. We also look at a message transmitted from Earth (Arecibo Observatory) that contains a lot of meaning but little information in the mathematical sense we define it here. We conclude that the study of non-human communication systems on our own planet can make a valuable contribution to the detection of extraterrestrial intelligence by providing quantitative general measures of communicative complexity. Studying the complex communication systems of other intelligent species on our own planet may also be one of the best ways to deprovincialize our thinking about extraterrestrial communication systems in general.

  13. EVALUATION OF MICROBIAL SURVIVAL IN EXTRATERRESTRIAL ENVIRONMENTS

    Directory of Open Access Journals (Sweden)

    Betül BULUÇ

    2012-08-01

    Full Text Available In this paper, the space environments where microbial terrestrial life could form and evolve in, were evaluted with the base of the physical and chemical properties. In addition, Earthial microbial life formation conditions in the interstellar medium and the other planets are investigated and the survival of microorganisms in the space environments are questioned. As a result, considering the aspects of terrestrial microbial life, we suggest that the space environment and other planets could not be a habitat for Earthial microorganisms.

  14. Sovereign CDS Contagion in the European Union: A Multivariate GARCH-in-Variables Analysis of Volatility Spill-Overs

    OpenAIRE

    Oliveira, Maria Alberta; Santos, Carlos

    2014-01-01

    GARCH-with-variables model is used to assess volatility contagion in the Eurozone Debt Crisis. Credit Default Swaps on sovereign debt with 3 years maturity are used as a reference financial instrument, covering the sample period from 2008-2013. Daily data on Credit Default Swaps is used. We conclude that there is strong statistical evidence of volatility contagion in CDS spreads from the Eurozone periphery to its core. However, the direction of contagion is contingent on the periphery and cor...

  15. Novel Flourescent Sensors for the Detection of Organic Molecules in Extraterrestrial Samples

    Science.gov (United States)

    Adkin, Roy C.; Bruce, James I.; Pearson, Victoria K.

    2015-04-01

    Organic compounds in extraterrestrial samples have mostly been elucidated by destructive analytical techniques therefore information regarding spatial relationships between minerals and organic species is lost. Minerals form under specific chemical and physical conditions so organic compounds associated with these minerals are likely to have formed under the same conditions. It is therefore possible to infer in which cosmological provinces their chemical evolution took place. We will describe progress towards developing fluorescent sensors that may resolve spatial discrimination. Lanthanide elements such as europium and terbium produce well defined line-like, high intensity and long lived fluorescent emissions. Interactions with organic molecules may alter the luminescent emission characteristics. The lanthanide atom needs to be rendered chemically inert but must remain susceptible to these organic molecule interactions. An organic ligand must be employed to attain this. DOTA (1,4,7,10-tetraazacyclododecanetetracetic acid) was chosen as a plausible organic ligand because its structure, a tetra-substituted cyclen ring, and ability to chelate are well characterized. It is also commercially available. Fluorescent lanthanide-DOTA complexes are used in many biological and analytical imaging applications so it is logical to investigate their applicability to fluorimetric analysis of extraterrestrial organics. Lanthanide-DOTA complexes are very stable because the lanthanide metal atom is enveloped within the DOTA structure. Experimental procedures were designed to investigate lanthanide/analyte interactions and their effect upon fluorescent emissions. A range of compounds were chosen giving a good representation of the organics identified in extraterrestrial samples and whether they may to interact with the lanthanide metal ion. An Europium-DOTA baseline fluorescent spectrum was obtained and compared against Europium-DOTA/analyte mixtures of a range of concentrations

  16. A Study on the Behavior of Volatility in Saudi Arabia Stock Market Using Symmetric and Asymmetric GARCH Models

    Directory of Open Access Journals (Sweden)

    Ahmed Shamiri

    2012-01-01

    Full Text Available Problem statement: This study examines several stylized facts (heavy-tailedness, leverage effect and persistence in volatility of stock price returns exploiting symmetric and asymmetric GARCH family models for Saudi Arabia. Approach: This study is carried out using closing stock market prices over 15 years covering the period 1 January 1994 to 31 March 2009. The sample period is divided into three sub-periods according to the local crisis in 2006. Results: The results reveal that asymmetric models with heavy tailed densities improve overall estimation of the conditional variance equation. Moreover, we find that AR (1-GJR GARCH model with Student-t outperform the other models during and before the local crisis in 2006, while AR (1-GARCH model with GED exhibits a better performance after the crisis. Furthermore, the findings reveal the existence of leverage effect at 1 percent significance level. Conclusion/Recommendations: Finally, the volatility persistent in the samples during and after crises decreases in all models under various distribution assumptions.

  17. Multivariate Time-Varying G-H Copula GARCH Model and Its Application in the Financial Market Risk Measurement

    Directory of Open Access Journals (Sweden)

    Qi-an Chen

    2015-01-01

    Full Text Available Taking full advantage of the strengths of G-H distribution, Copula function, and GARCH model in depicting the return distribution of financial asset, we construct the multivariate time-varying G-H Copula GARCH model which can comprehensively describe “asymmetric, leptokurtic, and heavy-tail” characteristics, the time-varying volatility characteristics, and the extreme-tail dependence characteristics of financial asset return. Based on the conditional maximum likelihood estimator and IFM method, we propose the estimation algorithm of model parameters. Using the quantile function and simulation method, we propose the calculation algorithm of VaR on the basis of this model. To apply this model on studying a real financial market risk, we select the SSCI (China, HSI (Hong Kong, China, TAIEX (Taiwan, China, and SP500 (USA from January 3, 2000, to June 18, 2010, as the samples to estimate the model parameters and to measure the VaRs of various index risk portfolios under different confidence levels empirically. The results of the application example are in line with the actual situation and the risk diversification theory of portfolio. To a certain extent, these results also justify the feasibility and effectiveness of the multivariate time-varying G-H Copula GARCH model in depicting the return distribution of financial assets.

  18. Modeling inflation rates and exchange rates in Ghana: application of multivariate GARCH models.

    Science.gov (United States)

    Nortey, Ezekiel Nn; Ngoh, Delali D; Doku-Amponsah, Kwabena; Ofori-Boateng, Kenneth

    2015-01-01

    This paper was aimed at investigating the volatility and conditional relationship among inflation rates, exchange rates and interest rates as well as to construct a model using multivariate GARCH DCC and BEKK models using Ghana data from January 1990 to December 2013. The study revealed that the cumulative depreciation of the cedi to the US dollar from 1990 to 2013 is 7,010.2% and the yearly weighted depreciation of the cedi to the US dollar for the period is 20.4%. There was evidence that, the fact that inflation rate was stable, does not mean that exchange rates and interest rates are expected to be stable. Rather, when the cedi performs well on the forex, inflation rates and interest rates react positively and become stable in the long run. The BEKK model is robust to modelling and forecasting volatility of inflation rates, exchange rates and interest rates. The DCC model is robust to model the conditional and unconditional correlation among inflation rates, exchange rates and interest rates. The BEKK model, which forecasted high exchange rate volatility for the year 2014, is very robust for modelling the exchange rates in Ghana. The mean equation of the DCC model is also robust to forecast inflation rates in Ghana.

  19. Orthopedic Management of Scoliosis by Garches Brace and Spinal Fusion in SMA Type 2 Children.

    Science.gov (United States)

    Catteruccia, Michela; Vuillerot, Carole; Vaugier, Isabelle; Leclair, Danielle; Azzi, Viviane; Viollet, Louis; Estournet, Brigitte; Bertini, Enrico; Quijano-Roy, Susana

    2015-11-21

    Scoliosis is the most debilitating issue in SMA type 2 patients. No evidence confirms the efficacy of Garches braces (GB) to delay definitive spinal fusion. Compare orthopedic and pulmonary outcomes in children with SMA type 2 function to management. We carried out a monocentric retrospective study on 29 SMA type 2 children who had spinal fusion between 1999 and 2009. Patients were divided in 3 groups: group 1-French patients (12 children) with a preventive use of GB; group 2-French patients (10 children) with use of GB after the beginning of the scoliosis curve; and group 3-Italian patients (7 children) with use of GB after the beginning of the scoliosis curve referred to our centre to perform orthopedic preoperative management. Mean preoperative and postoperative Cobb angle were significantly lower in the group 1 of proactively braced than in group 2 or 3 (Anova p = 0.03; Kruskal Wallis test p = 0.05). Better surgical results were observed in patients with a minor preoperative Cobb angle (r = 0.92 p SMA type 2. Further prospective studies comparing SMA management are needed to confirm these results. Therapeutic Level III. See Instructions to Authors on jbjs.org for a complete description of levels of evidence (Retrospective comparative study).

  20. Forecasting of exported volume for brazilian fruits by time series analysis: an arima/garch approach

    Directory of Open Access Journals (Sweden)

    Abdinardo Moreira Barreto de Oliveira

    2015-06-01

    Full Text Available The aim of this paper was to offer econometric forecasting models to the Brazilian exported volume fruits, with a view to assisting the planning and production control, also motivated by the existence of a few published papers dealing with this issue. In this sense, it was used the ARIMA/GARCH models, considering, likewise, the occurrence of a multiplicative stochastic seasonality in these series. They were collected 300 observations of exported net weight (kg between Jan/1989 and Dec/2013 of the following fruits: pineapple, banana, orange, lemon, apple, papaya, mango, watermelon, melon and grape, which selection criteria was its importance in the exported basket fruit, because they represented 97% of total received dollars, and 99% of total volume sold in 2010, of a population about 28 kinds of exported fruits. The results showed that it was not only observed the existence of a 12 month multiplicative seasonality in banana and mango. On the other hand, they were identified two fruits groups: (1 those which are continuously exported, and (2 those which have export peaks. On the quality of the models, they were considered satisfactory for six of the ten fruits analyzed. On the volatility, it was seen a high persistence in banana and papaya series, pointing to the existence of a structural break in time series, which could be linked to the economic crises happened in the last 17 years.

  1. Prediction of selected Indian stock using a partitioning–interpolation based ARIMA–GARCH model

    Directory of Open Access Journals (Sweden)

    C. Narendra Babu

    2015-07-01

    Full Text Available Accurate long-term prediction of time series data (TSD is a very useful research challenge in diversified fields. As financial TSD are highly volatile, multi-step prediction of financial TSD is a major research problem in TSD mining. The two challenges encountered are, maintaining high prediction accuracy and preserving the data trend across the forecast horizon. The linear traditional models such as autoregressive integrated moving average (ARIMA and generalized autoregressive conditional heteroscedastic (GARCH preserve data trend to some extent, at the cost of prediction accuracy. Non-linear models like ANN maintain prediction accuracy by sacrificing data trend. In this paper, a linear hybrid model, which maintains prediction accuracy while preserving data trend, is proposed. A quantitative reasoning analysis justifying the accuracy of proposed model is also presented. A moving-average (MA filter based pre-processing, partitioning and interpolation (PI technique are incorporated by the proposed model. Some existing models and the proposed model are applied on selected NSE India stock market data. Performance results show that for multi-step ahead prediction, the proposed model outperforms the others in terms of both prediction accuracy and preserving data trend.

  2. Modeling the relationship between climate oscillations and drought by a multivariate GARCH model

    Science.gov (United States)

    Modarres, R.; Ouarda, T. B. M. J.

    2014-01-01

    Typical multivariate time series models may exhibit comovement in mean but not in variance of hydrologic and climatic variables. This paper introduces multivariate generalized autoregressive conditional heteroscedasticity (GARCH) models to capture the comovement of the variance or the conditional covariance between two hydroclimatic time series. The diagonal vectorized and Baba-Engle-Kroft-Kroner models are developed to evaluate the covariance between drought and two atmospheric circulations, Southern Oscillation Index (SOI) and North Atlantic Oscillation (NAO) time series during 1954-2000. The univariate generalized autoregressive conditional heteroscedasticity model indicates a strong persistency level in conditional variance for NAO and a moderate persistency level for SOI. The conditional variance of short-term drought index indicates low level of persistency, while the long-term index drought indicates high level of persistency in conditional variance. The estimated conditional covariance between drought and atmospheric indices is shown to be weak and negative. It is also observed that the covariance between drought and atmospheric indices is largely dependent on short-run variance of atmospheric indices rather than their long-run variance. The nonlinearity and stationarity tests show that the conditional covariances are nonlinear but stationary. However, the degree of nonlinearity is higher for the covariance between long-term drought and atmospheric indices. It is also observed that the nonlinearity of NAO is higher than that for SOI, in contrast to the stationarity which is stronger for SOI time series.

  3. Cultural aspects of the search for extraterrestrial intelligence

    Science.gov (United States)

    Billingham, J.

    SETI is an acronym which stands for the Search for Extraterrestrial Intelligence. The NASA SETI High Resolution Microwave Survey Project is a new and comprehensive search for evidence of microwave signals from extraterrestrial civilizations. It will formally begin on October 12, 1992, and last to the end of the century. The discovery of another form of intelligent life would be an important milestone for our civilization. In addition to the new scientific knowledge that we might acquire on the chemistry, physiology, behavior and evolutionary history of extraterrestrial life forms, we may also learn of the cultural achievements of another civilization, or indeed of many other civilizations. It is likely that the society that we detect will be much in advance of our own, so that they may long ago have passed through the evolutionary stage we are at now. The implications of such a discovery would have important consequences for our own future. This paper presents an analysis of some of the important areas which will require study as we approach the beginning of the NASA search. There are significant questions about the ease or difficulty of incorporating the new knowledge into the belief structures of different religions. Sociological and educational changes over time may equal or exceed those of the Copernican revolution. The status of the other civilization relative to ours is a challenging question for international space law. There are institutional and international questions on who will represent Earth in any future interstellar communication endeavors that we may attempt. There may be challenges in how we absorb the knowledge of an advanced technology. In political science we may have much to learn from their history, and what influence it may have on our own future. Last but not least, there is the effect of the discovery on individual and group psychology. These are the cultural aspects of SETI. Each area warrants further study, and recommendations are made

  4. The Role of Extraterrestrial Materials in the Origin of Life

    Science.gov (United States)

    Sandford, Scott A.

    2016-01-01

    It has been well established for some time now that C-rich organic materials are relatively common in a number of environments in space. This is known through the telescopic detection of these materials using spectroscopy techniques in the infrared and sub-millimeter wavelength ranges and through the identification of organics in extraterrestrial materials. Extraterrestrial materials in which organics have been found include collected meteorites and interplanetary dust particles, and samples returned by NASA spacecraft from comets. These organics are produced by a variety of astrochemical processes. Despite their abiotic origins, these organic materials of are considerable interest to astrobiology for several reasons. First, organic materials of any composition are important as a means of delivering the elements C, H, O, and N to the surfaces of newly formed planets, and these elements are likely critical to the origin and subsequent evolution of life (certainly for life as we know it). In addition, it is clear that at least a portion of the organics found in space are in the form of molecules that play important roles in modern biology - for example, molecules like amino acids, amphiphiles, quinones, etc. Thus, the delivery of extraterrestrial organics to planetary surfaces brings not only bulk C, H, O, and N, but also molecular complexity in forms that are potentially useful for the origin and early evolution of life. This suggests that the production and delivery of cosmic organic compounds may have played key roles in the origin of life on Earth and, by extension, on other planets in the universe.

  5. Adenosine triphosphate (ATP) as a possible indicator of extraterrestrial biology

    Science.gov (United States)

    Chappelle, E. W.; Picciolo, G. L.

    1974-01-01

    The ubiquity of adenosine triphosphate (ATP) in terrestrial organisms provides the basis for proposing the assay of this vital metabolic intermediate for detecting extraterrestrial biological activity. If an organic carbon chemistry is present on the planets, the occurrence of ATP is possible either from biosynthetic or purely chemical reactions. However, ATP's relative complexity minimizes the probability of abiogenic synthesis. A sensitive technique for the quantitative detection of ATP was developed using the firefly bioluminescent reaction. The procedure was used successfully for the determination of the ATP content of soil and bacteria. This technique is also being investigated from the standpoint of its application in clinical medicine.

  6. The Recognition of Extraterrestrial Intelligence - Are Humans up to it

    Science.gov (United States)

    Pugsley, D.

    SETI strategies tend to overlook the uncertain nature of intelligence. How can we search for intelligence when we do not really know what it is? This paper explores the nature of intelligence and tries to identify its essence. It questions the validity of the human model of intelligence that is used to measure intelligence in terrestrial animals and underpins SETI projects. It concludes that we may only be able to recognise intelligence in an extraterrestrial animal from its behaviour and proposes several patterns of behaviour that could be used.

  7. Planetary Protection Knowledge Gaps for Human Extraterrestrial Missions: Workshop Report

    Science.gov (United States)

    Race, Margaret S. (Editor); Johnson, James E. (Editor); Spry, James A. (Editor); Siegel, Bette; Conley, Catharine A.

    2015-01-01

    This report on Planetary Protection Knowledge Gaps for Human Extraterrestrial Missions summarizes the presentations, deliberations and findings of a workshop at NASA Ames Research Center, March 24-26, 2015, which was attended by more than 100 participants representing a diverse mix of science, engineering, technology, and policy areas. The main objective of the three-day workshop was to identify specific knowledge gaps that need to be addressed to make incremental progress towards the development of NASA Procedural Requirements (NPRs) for Planetary Protection during human missions to Mars.

  8. New insights in the bacterial spore resistance to extreme terrestrial and extraterrestrial factors

    Science.gov (United States)

    Moeller, Ralf; Horneck, Gerda; Reitz, Guenther

    Based on their unique resistance to various space parameters, Bacillus endospores are one of the model systems used for astrobiological studies. The extremely high resistance of bacterial endospores to environmental stress factors has intrigued researchers since long time and many characteristic spore features, especially those involved in the protection of spore DNA, have already been uncovered. The disclosure of the complete genomic sequence of Bacillus subtilis 168, one of the often used astrobiological model system, and the rapid development of tran-scriptional microarray techniques have opened new opportunities of gaining further insights in the enigma of spore resistance. Spores of B. subtilis were exposed to various extreme ter-restrial and extraterrestrial stressors to reach a better understanding of the DNA protection and repair strategies, which them to cope with the induced DNA damage. Following physical stress factors of environmental importance -either on Earth or in space -were selected for this thesis: (i) mono-and polychromatic UV radiation, (ii) ionizing radiation, (iii) exposure to ultrahigh vacuum; and (iv) high shock pressures simulating meteorite impacts. To reach a most comprehensive understanding of spore resistance to those harsh terrestrial or simulated extraterrestrial conditions, a standardized experimental protocol of the preparation and ana-lyzing methods was established including the determination of the following spore responses: (i) survival, (ii) induced mutations, (iii) DNA damage, (iv) role of different repair pathways by use of a set of repair deficient mutants, and (v) transcriptional responses during spore germi-nation by use of genome-wide transcriptome analyses and confirmation by RT-PCR. From this comprehensive set of data on spore resistance to a variety of environmental stress parameters a model of a "built-in" transcriptional program of bacterial spores in response to DNA damaging treatments to ensure DNA restoration

  9. 基于GARCH-EVT-POT模型的VaR风险测度研究--以沪深300股指为例

    Institute of Scientific and Technical Information of China (English)

    李行

    2016-01-01

    2015年,中国股票市场风云变幻,跌宕起伏。股票市场的过山车波动,为进一步增强风险管理意识,提高风险测量水平提出了更高的要求。本文以能代表中国股市六层市值的沪深300股指为例,将GARCH模型与极值理论相结合,同时,针对性的运用描述后尾的GARCH-t模型,建立GARCH-t-EVT-POT-VaR模型,对沪深300股指进行风险测度。后验测试发现,GARCH-t-EVT-POT-VaR与GARCH-t-VaR均能较好的描述股市风险,但GARCH-t-EVT-POT-VaR模型的准确性更高,效果更好。

  10. The Ultra short-term prediction of wind power based on ARMA-GARCH model%基于 ARMA-GARCH 模型的超短期风功率预测研究

    Institute of Scientific and Technical Information of China (English)

    田波; 朴在林; 郭丹; 王慧

    2016-01-01

    Wind power prediction is very important to improve the power quality and the safe operation of power sys -tem.The ultra short-term prediction of wind power data is carried out in a wind farm in Chifeng of Inner Mongola based on time series analysis , and the ARMA ( Autoregressive Moving Average ) model of time series is built through the stationary test of data.Through ARCH effect of the residual of ARMA model by Lagrange Multiplier (LM), the corresponding ARMA-GARCH model is set up .Through the comparison of the wind power prediction by using ARMA model , ARMA-ARCH model and ARMA-GARCH model respectively , ARMA-GARCH model possesses higher accura-cy on the residual sequence of the data with the long term correlation .%风功率预测对提高电能质量和电力系统的安全运行具有重要意义。基于时间序列的方法,对内蒙古赤峰地区某风场的风功率数据进行了超短期预测,通过对数据平稳性检验的结果,建立了时间序列的ARMA模型,利用拉格朗日乘子检验的方法,检验ARMA模型具有ARCH效应,并建立适合的ARMA-GARCH模型。结论通过对比ARMA模型,ARMA-ARCH模型和ARMA-GARCH模型的风功率预测精度可知,在解决数据的残差序列异方差函数具有长期相关性时,ARMA-GARCH模型能够有效的提高预测精度。

  11. Carbon option pricing based on fractional Brownian motion combined with GARCH model%基于 GARCH-分形布朗运动模型的碳期权定价研究

    Institute of Scientific and Technical Information of China (English)

    张晨; 彭婷; 刘宇佳

    2015-01-01

    文章将广义自回归条件异方差(generalized autoregressive conditional heteroskedasticity ,GARCH )模型和分形布朗运动结合引入碳金融期权定价研究中。通过对欧洲碳排放配额(European Union Allowance , EUA)期货收盘价的样本数据检验,发现其存在尖峰厚尾、条件异方差性和分形特征;采用GARCH模型拟合并预测碳价收益率波动率;将预测的波动率作为输入值代入分形布朗运动期权定价方法,运用蒙特卡罗模拟对EUA期货期权进行定价,并与B‐S期权定价法(Black‐Scholes Option Pricing Model)比较。结果表明,基于GARCH分形布朗运动模型的碳期权定价法预测精度有显著提高。%This paper introduces the idea of combining generalized autoregressive conditional heteroskedasticity (GARCH) model and fractional Brownian motion into carbon option pricing .Firstly ,the test results from closing price of European Union Allowance (EUA) Futures show that obvious peak and fat tails ,heterosce‐dasticity and fractal feature reside in the data .Secondly ,the GARCH model is used to fit the volatility of EUA Futures price ,which can reasonably describe and forecast the time‐varying volatility .With the forecas‐ted volatility being the input in fractional Brownian motion carbon option pricing ,the Monte Carlo simulation is used to simulate the pricing of EUA Futures options ,and then the pricing result is compared with that of Black‐Scholes option pricing model .The result shows that carbon option pricing based on fractional Brownian motion combined with GARCH model can improve the pricing accuracy .

  12. Anthropological Contributions to the Search for Extraterrestrial Intelligence

    Science.gov (United States)

    Vakoch, D. A.

    2009-12-01

    Three recent annual conferences of the American Anthropological Association (AAA) have included symposia on the Search for Extraterrestrial Intelligence (SETI). This paper reviews these symposia, which dealt with themes associated with the overarching AAA conference themes for each year: in 2004, the SETI session addressed Anthropology, Archaeology, and Interstellar Communication: Science and the Knowledge of Distant Worlds; in 2005, it dealt with Historical Perspectives on Anthropology and SETI; and in 2006, the session examined Culture, Anthropology, and SETI. Among the topics considered in these symposia were analogues for contact with extraterrestrial intelligence (ETI), examining anthropologists’ experience in the field encountering other cultures-past and present. Similarly, the methodologies of archaeologists provide analogies for making contact with temporally distant civilizations, based on reconstructions from fragmentary information. Case studies helped make such analogies concrete in the symposia. The challenges of comprehending intelligences with different mental worlds was explored through a study of the meetings of Neanderthals and Homo sapiens, for example, while the decryption of Mayan hieroglyphics provided lessons on understanding others of own species.

  13. Funding the Search for Extraterrestrial Intelligence with a Lottery Bond

    CERN Document Server

    Haqq-Misra, Jacob

    2013-01-01

    I propose the establishment of a SETI Lottery Bond to provide a continued source of funding for the search for extraterrestrial intelligence (SETI). The SETI Lottery Bond is a fixed rate perpetual bond with a lottery at maturity, where maturity occurs only upon discovery and confirmation of extraterrestrial intelligent life. Investors in the SETI Lottery Bond purchase shares that yield a fixed rate of interest that continues indefinitely until SETI succeeds---at which point a random subset of shares will be awarded a prize from a lottery pool. SETI Lottery Bond shares also are transferable, so that investors can benefact their shares to kin or trade them in secondary markets. The total capital raised this way will provide a fund to be managed by a financial institution, with annual payments from this fund to support SETI research, pay investor interest, and contribute to the lottery fund. Such a plan could generate several to tens of millions of dollars for SETI research each year, which would help to revital...

  14. Religions and extraterrestrial life how will we deal with it?

    CERN Document Server

    Weintraub, David A

    2014-01-01

    In the twenty-first century, the debate about life on other worlds is quickly changing from the realm of speculation to the domain of hard science. Within a few years, as a consequence of the rapid discovery by astronomers of planets around other stars, astronomers very likely will have discovered clear evidence of life beyond the Earth. Such a discovery of extraterrestrial life will change everything.  Knowing the answer as to whether humanity has company in the universe will trigger one of the greatest intellectual revolutions in history, not the least of which will be a challenge for at least some terrestrial religions. Which religions will handle the discovery of extraterrestrial life with ease and which will struggle to assimilate this new knowledge about our place in the universe? Some religions as currently practiced appear to only be viable on Earth. Other religions could be practiced on distant worlds but nevertheless identify both Earth as a place and humankind as a species of singular spiritual re...

  15. Extrasolar asteroid mining as forensic evidence for extraterrestrial intelligence

    Science.gov (United States)

    Forgan, Duncan H.; Elvis, Martin

    2011-10-01

    The development of civilisations like ours into spacefaring, multi-planet entities requires significant raw materials to construct vehicles and habitats. Interplanetary debris, including asteroids and comets, may provide such a source of raw materials. In this article we present the hypothesis that extraterrestrial intelligences (ETIs) engaged in asteroid mining may be detectable from Earth. Considering the detected disc of debris around Vega as a template, we explore the observational signatures of targeted asteroid mining (TAM), such as unexplained deficits in chemical species, changes in the size distribution of debris and other thermal signatures which may be detectable in the spectral energy distribution (SED) of a debris disc. We find that individual observational signatures of asteroid mining can be explained by natural phenomena, and as such they cannot provide conclusive detections of ETIs. But, it may be the case that several signatures appearing in the same system will prove harder to model without extraterrestrial involvement. Therefore signatures of TAM are not detections of ETI in their own right, but as part of "piggy-back" studies carried out in tandem with conventional debris disc research, they could provide a means of identifying unusual candidate systems for further study using other SETI techniques.

  16. The Log Log Prior for the Frequency of Extraterrestrial Intelligences

    CERN Document Server

    Lacki, Brian C

    2016-01-01

    It is unclear how frequently life and intelligence arise on planets. I consider a Bayesian prior for the probability P(ETI) that intelligence evolves at a suitable site, with weight distributed evenly over ln(1 - ln P(ETI)). This log log prior can handle a very wide range of P(ETI) values, from 1 to 10^(-10^122), while remaining responsive to evidence about extraterrestrial societies. It is motivated by our uncertainty in the number of conditions that must be fulfilled for intelligence to arise, and it is related to considerations of information, entropy, and state space dimensionality. After setting a lower limit to P(ETI) from the number of possible genome sequences, I calculate a Bayesian confidence of 18% that aliens exist within the observable Universe. With different assumptions about the minimum P(ETI) and the number of times intelligence can appear on a planet, this value falls between 1.4% and 47%. Overall, the prior leans towards our being isolated from extraterrestrial intelligences, but indicates ...

  17. Orthopedic Management of Scoliosis by Garches Brace and Spinal Fusion in SMA Type 2 Children

    Science.gov (United States)

    Catteruccia, Michela; Vuillerot, Carole; Vaugier, Isabelle; Leclair, Danielle; Azzi, Viviane; Viollet, Louis; Estournet, Brigitte; Bertini, Enrico; Quijano-Roy, Susana

    2015-01-01

    Background: Scoliosis is the most debilitating issue in SMA type 2 patients. No evidence confirms the efficacy of Garches braces (GB) to delay definitive spinal fusion. Objective: Compare orthopedic and pulmonary outcomes in children with SMA type 2 function to management. Method: We carried out a monocentric retrospective study on 29 SMA type 2 children who had spinal fusion between 1999 and 2009. Patients were divided in 3 groups: group 1-French patients (12 children) with a preventive use of GB; group 2-French patients (10 children) with use of GB after the beginning of the scoliosis curve; and group 3-Italian patients (7 children) with use of GB after the beginning of the scoliosis curve referred to our centre to perform orthopedic preoperative management. Results: Mean preoperative and postoperative Cobb angle were significantly lower in the group 1 of proactively braced than in group 2 or 3 (Anova p = 0.03; Kruskal Wallis test p = 0.05). Better surgical results were observed in patients with a minor preoperative Cobb angle (r = 0.92 p <  0.0001). Fewer patients in the group 1 proactively braced required trunk casts and/or halo traction and an additional anterior fusion in comparison with patients in the group 2 and 3. Moreover, major complications tend to be less in the group 1 proactively braced. No significant differences were found between groups in pulmonary outcome measures. Conclusions: A proactive orthotic management may improve orthopedic outcome in SMA type 2. Further prospective studies comparing SMA management are needed to confirm these results. Level of Evidence: Therapeutic Level III. See Instructions to Authors on jbjs.org for a complete description of levels of evidence (Retrospective comparative study). PMID:27858747

  18. THE IMPACT OF POLITICAL AND ECONOMIC NEWS ON THE EURO/RON EXCHANGE RATE: A GARCH APPROACH

    Directory of Open Access Journals (Sweden)

    Mihai Niţoi

    2012-12-01

    Full Text Available Within this study we try to capture the impact of political news and economic news from euro area on the exchange rate between Romanian currency and euro. In order to do this we used a GARCH model. As we observed, both variables influence the exchange rate, this fact implying national currency depreciation and a volatility growth. The political news and the economic news positively affect the euro/ron exchange rate volatility. The two factors conjugation, as it has happened in the recent period is to be avoided because it can have financial and economic consequences with a very high cost for Romania.

  19. Study of the cross-market effects of Brexit based on the improved symbolic transfer entropy GARCH model-An empirical analysis of stock-bond correlations.

    Science.gov (United States)

    Chen, Xiurong; Tian, Yixiang; Zhao, Rubo

    2017-01-01

    In this paper, we study the cross-market effects of Brexit on the stock and bond markets of nine major countries in the world. By incorporating information theory, we introduce the time-varying impact weights based on symbolic transfer entropy to improve the traditional GARCH model. The empirical results show that under the influence of Brexit, flight-to-quality not only commonly occurs between the stocks and bonds of each country but also simultaneously occurs among different countries. We also find that the accuracy of the time-varying symbolic transfer entropy GARCH model proposed in this paper has been improved compared to the traditional GARCH model, which indicates that it has a certain practical application value.

  20. Study of the cross-market effects of Brexit based on the improved symbolic transfer entropy GARCH model—An empirical analysis of stock–bond correlations

    Science.gov (United States)

    Chen, Xiurong; Zhao, Rubo

    2017-01-01

    In this paper, we study the cross-market effects of Brexit on the stock and bond markets of nine major countries in the world. By incorporating information theory, we introduce the time-varying impact weights based on symbolic transfer entropy to improve the traditional GARCH model. The empirical results show that under the influence of Brexit, flight-to-quality not only commonly occurs between the stocks and bonds of each country but also simultaneously occurs among different countries. We also find that the accuracy of the time-varying symbolic transfer entropy GARCH model proposed in this paper has been improved compared to the traditional GARCH model, which indicates that it has a certain practical application value. PMID:28817712

  1. 基于GARCH-EVT-VaR模型的碳市场风险计量实证研究%Value-at-Risk Estimation of Carbon Spot Markets Based on an Integrated GARCH-EVT-VaR Model

    Institute of Scientific and Technical Information of China (English)

    蒋晶晶; 叶斌; 马晓明

    2015-01-01

    对欧盟碳市场风险进行实证研究,在分析碳市场价格波动特征基础上,将条件方差和极值理论纳入VaR计量框架,建立量化碳市场价格波动风险的GARCH-EVT-VaR模型.应用该模型对欧盟碳排放交易市场(EU ETS)进行实证研究,结果显示:碳市场价格波动具有尖峰、厚尾、自相关、波动性聚类和条件方差等典型特征,EUA和CER价格波动呈现显著同步性;碳市场存在显著的极端价格波动风险,GARCH-EVT-VaR模型能够更准确地量化碳市场风险,从而为应对极端事件预留充足的风险储备.

  2. Optimal strategies on management of electricity risks by futures. An empirical analysis by multivariant GARCH-models; Optimale Strategien zum Management von Elektrizitaetsrisiken mit Futures. Eine empirische Analyse mit multivarianten GARCH-Modellen

    Energy Technology Data Exchange (ETDEWEB)

    Rodt, M.

    2003-07-01

    The optimal risk management policy of an electric utility is analyzed both theoretically and empirically. The best strategy is found to be in futures. The theoretical discussion is supplemented by an empirical description and analysis of strategies based on empirical data of the German electricity stock exchange EEX and the scandinavian Nord Pool. Apart from conventional methods, also multivariate GARCH methods are employed. (orig.) [German] In der vorliegenden Arbeit wird die optimale Risikopolitik eines Elektrizitaetshaendlers theoretisch und empirisch analysiert. Eine Diskussion des verfuegbaren risikopolitischen Instrumentariums ergibt, dass boersengehandelte Elektrizitaetsfutures am besten zur Steuerung der betrachteten Risiken geeignet sind. Mittels einer formalen Ableitung werden die optimalen zeitvariierenden Strategien sowie Bedingungen fuer deren Praeferenzfreiheit ermittelt. Hierbei zeigt sich, dass die optimale Absicherung bei Gueltigkeit der Praeferenzfreiheitsbedingungen einer Varianzminimierung entspricht. Eine empirische Ermittlung und Analyse praeferenzfreier optimaler Strategien basierend auf empirischen Daten der deutschen Stromboerse EEX und der skandinavischen Stromboerse Nord Pool ergaenzen die theoretische Betrachtung. Hierbei kommen neben herkoemmlichen Verfahren auch multivariate GARCH-Verfahren zum Einsatz, um zu pruefen, mit welchem Verfahren in den untersuchten Perioden und Maerkten die hoechste Varianzreduzierung erzielt werden kann. (orig.)

  3. Measurement to stock market liquidity risk based on GARCH-VaR model%基于GARCH-VaR模型的股票流动性风险度量

    Institute of Scientific and Technical Information of China (English)

    刘晓青; 杨一文

    2015-01-01

    Based on investigation to liquidity risk before, this paper focuses more on the heterogeneity of stock market. Firstly, it does MODWT to the liquidity scale data, then calculates VaR of each scale using GARCH-VaR model, finally tests the effectiveness of the model. The paper proves risk capacity varies with capital scale, and the various risk pressure long-term and short-term investors face.%在原有流动性风险研究的基础上,充分考虑股票市场异质性,对流动性指标数据进行了最大重复离散小波变换(MODWT),然后运用GARCH-VaR模型分别计算各尺度上的VaR值,并对其进行了有效性检验。通过对各尺度VaR值的统计结果进行分析,验证所投资市场资本规模对风险容纳能力的不同以及长期投资者与短期投资者面对的不同流动性压力。

  4. Siderophilic Cyanobacteria for the Development of Extraterrestrial Photoautotrophic Biotechnologies

    Science.gov (United States)

    Brown, I. I.; McKay, D. S.

    2010-01-01

    In-situ production of consumables (mainly oxygen) using local resources (In-Situ Resource Utilization-ISRU) will significantly facilitate current plans for human exploration and settlement of the solar system, starting with the Moon. With few exceptions, nearly all technologies developed to date have employed an approach based on inorganic chemistry. None of these technologies include concepts for integrating the ISRU system with a bioregenerative life support system and a food production system. Therefore, a new concept based on the cultivation of cyanobacteria (CB) in semi-closed biogeoreactor, linking ISRU, a biological life support system, and food production, has been proposed. The key feature of the biogeoreactor is to use lithotrophic CB to extract many needed elements such as Fe directly from the dissolved regolith and direct them to any technological loop at an extraterrestrial outpost. Our studies showed that siderophilic (Fe-loving) CB are capable to corrode lunar regolith stimulants because they secrete chelating agents and can tolerate [Fe] up to 1 mM. However, lunar and Martian environments are very hostile (very high UV and gamma-radiation, extreme temperatures, deficit of water). Thus, the selection of CB species with high potential for extraterrestrial biotechnologies that may be utilized in 15 years must be sponsored by NASA as soon as possible. The study of the genomes of candidate CB species and the metagenomes of the terrestrial environments which they inhabit is critical to make this decision. Here we provide preliminary results about peculiarities of the genomes of siderophilic CB revealed by analyzing the genome of siderophilic cyanobacterium JSC-1 and the metagenome of iron depositing hot spring (IDHS) Chocolate Pots (Yellowstone National Park, Wyoming, USA). It has been found that IDHS are richer with ferrous iron than the majority of hot springs around the world. Fe2+ is known to increase the magnitude of oxidative stress in prokaryotes

  5. Research in theoretical physics. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Domokos, G.; Kovesi-Domokos, S.

    1998-06-01

    This report summarizes the research carried out under Grant DE-FG02-85ER40211. The main topics covered are: astroparticle physics at very high and ultrahigh energies; search for new physics by means of detectors of ultrahigh energy particles of extraterrestrial origin. Methods for searching in heavy quark decays for signatures of physics beyond the standard model are developed.

  6. Extrasolar Asteroid Mining as Forensic Evidence for Extraterrestrial Intelligence

    CERN Document Server

    Forgan, Duncan

    2011-01-01

    The development of civilisations like ours into spacefaring, multi-planet entities requires significant raw materials to construct vehicles and habitats. Interplanetary debris, including asteroids and comets, may provide such a source of raw materials. In this article we present the hypothesis that extraterrestrial intelligences (ETIs) engaged in asteroid mining may be detectable from Earth. Considering the detected disc of debris around Vega as a template, we explore the observational signatures of targeted asteroid mining (TAM), such as unexplained deficits in chemical species, changes in the size distribution of debris and other thermal signatures which may be detectable in the spectral energy distribution (SED) of a debris disc. We find that individual observational signatures of asteroid mining can be explained by natural phenomena, and as such they cannot provide conclusive detections of ETIs. But, it may be the case that several signatures appearing in the same system will prove harder to model without...

  7. IR Spectroscopy and Photo-Chemistry of Extraterrestrial Ices

    Science.gov (United States)

    Bernstein, Max P.; Mastrapa, Rachel; Elsila, Jamie; Sandford, Scott

    2005-01-01

    Dense molecular clouds from which planetary systems form and the outer Solar System are both cold environments dominated by ices. Infrared (IR) spectroscopy is used to probe these ices, but the IR absorptions of molecules depend on the conditions. As a result appropriate lab data is needed to correctly fit spectra of extraterrestrial ices. Such fits have shown that most of these ices are composed primarily of H2O, but also contain 1-10 percent of other simple molecules such as CO2, CO, CH4, & NH3;. We shall present near IR spectra of ice mixtures of relevance to icy outer Solar System bodies and show that they still hold surprises, such as the Cheshire cat-like CO2 (2v3) overtone near 2.134 micrometers (4685 cm-1) that is absent from spectra of pure CO2 but present in H2O-CO2 mixtures.

  8. A Numerical Testbed for Hypotheses of Extraterrestrial Life and Intelligence

    CERN Document Server

    Forgan, Duncan

    2008-01-01

    The search for extraterrestrial intelligence (SETI) has been heavily influenced by solutions to the Drake Equation, which returns an integer value for the number of communicating civilisations resident in the Milky Way, and by the Fermi Paradox, glibly stated as: "If they are there, where are they?". Both rely on using average values of key parameters, such as the mean signal lifetime of a communicating civilisation. A more accurate answer must take into account the distribution of stellar, planetary and biological attributes in the galaxy, as well as the stochastic nature of evolution itself. This paper outlines a method of Monte Carlo realisation which does this, and hence allows an estimation of the distribution of key parameters in SETI, as well as allowing a quantification of their errors (and the level of ignorance therein). Furthermore, it provides a means for competing theories of life and intelligence to be compared quantitatively.

  9. Arsenic in the evolution of earth and extraterrestrial ecosystems

    Science.gov (United States)

    Oremland, R.S.; Saltikov, C.W.; Wolfe-Simon, Felisa; Stolz, J.F.

    2009-01-01

    If you were asked to speculate about the form extra-terrestrial life on Mars might take, which geomicrobial phenomenon might you select as a model system, assuming that life on Mars would be 'primitive'? Give your reasons. At the end of my senior year at Rensselaer Polytechnic Institute in 1968, I took Professor Ehrlich's final for his Geomicrobiology course. The above question beckoned to me like the Sirens to Odysseus, for if I answered, it would take so much time and thought that I would never get around to the exam's other essay questions and consequently, would be "shipwrecked" by flunking the course. So, I passed it up. With this 41-year perspective in mind, this manuscript is now submitted to Professor Ehrlich for (belated) "extra-credit." R.S. Oremland ?? Taylor & Francis Group, LLC.

  10. At the frontiers of knowledge: some issues of extraterrestrial research

    Science.gov (United States)

    Arnould, Jacques

    In The Structure of Scientific Revolutions, Kuhn demonstrates why scientific development is not an essentially cumulative process and how the major transformations of science are the result of “scientific revolutions”. At the origin of these changes is the discovery of an anomaly that, at a time of history, basically highlights failure science that Kuhn says 'normal', that is built around a “paradigm” that provides methods, standardized, efficient but obtuse scientific tools, as well as socio-economic biases. "The discovery, wrote Kuhn, starts with the consciousness of an anomaly, i.e. the impression that nature, one way or another, contradicts the expected results of the paradigm that governs normal science." Research of a life and an extraterrestrial intelligence has the singular character to include the anomaly as one of its main goals: what are its results in the future, they will contradict or at least jostle the results of scientific works, sometimes too quickly transformed into evidence.

  11. Searching for Extraterrestrial Intelligence SETI Past, Present, and Future

    CERN Document Server

    Shuch, H Paul

    2011-01-01

    This book is a collection of essays written by the very scientists and engineers who have led, and continue to lead, the scientific quest known as SETI, the search for extraterrestrial intelligence. Divided into three parts, the first section, ‘The Spirit of SETI Past’, written by the surviving pioneers of this then emerging discipline, reviews the major projects undertaken during the first 50 years of SETI science and the results of that research. In the second section, ‘The Spirit of SETI Present’, the present-day science and technology is discussed in detail, providing the technical background to contemporary SETI instruments, experiments, and analytical techniques, including the processing of the received signals to extract potential alien communications. In the third and final section, ‘The Spirit of SETI Future’, the book looks ahead to the possible directions that SETI will take in the next 50 years, addressing such important topics as interstellar message construction, the risks and assump...

  12. Detecting extraterrestrial life with the Colossus telescope using photosynthetic biosignatures

    Science.gov (United States)

    Berdyugina, S.; Kuhn, J.; Harrington, D.; Moretto, G.; Langlois, M.; Halliday, D.; Harlingten, C.

    2014-03-01

    We propose to search for life on Earth-like planets in habitable zones using photosynthesis biosignatures. Many life forms on Earth process the solar light and utilize it to support their own activity and to provide a valuable energy source for other life forms. We expect therefore that photosynthesis is very likely to arise on another planet and can produce conspicuous biosignatures. We have recently identified biological polarization effects, e.g., selective light absorption or scattering by photosynthetic molecules which can be used for remote detection of extraterrestrial life. Here we present synthetic spectra and polarization of Earth-like planets with photosynthetic life and evaluate the sensitivity of the Colossus telescope for their remote detection in the solar neighborhood.

  13. Analytical SuperSTEM for extraterrestrial materials research

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, J P; Dai, Z R

    2009-09-08

    Electron-beam studies of extraterrestrial materials with significantly improved spatial resolution, energy resolution and sensitivity are enabled using a 300 keV SuperSTEM scanning transmission electron microscope with a monochromator and two spherical aberration correctors. The improved technical capabilities enable analyses previously not possible. Mineral structures can be directly imaged and analyzed with single-atomic-column resolution, liquids and implanted gases can be detected, and UV-VIS optical properties can be measured. Detection limits for minor/trace elements in thin (<100 nm thick) specimens are improved such that quantitative measurements of some extend to the sub-500 ppm level. Electron energy-loss spectroscopy (EELS) can be carried out with 0.10-0.20 eV energy resolution and atomic-scale spatial resolution such that variations in oxidation state from one atomic column to another can be detected. Petrographic mapping is extended down to the atomic scale using energy-dispersive x-ray spectroscopy (EDS) and energy-filtered transmission electron microscopy (EFTEM) imaging. Technical capabilities and examples of the applications of SuperSTEM to extraterrestrial materials are presented, including the UV spectral properties and organic carbon K-edge fine structure of carbonaceous matter in interplanetary dust particles (IDPs), x-ray elemental maps showing the nanometer-scale distribution of carbon within GEMS (glass with embedded metal and sulfides), the first detection and quantification of trace Ti in GEMS using EDS, and detection of molecular H{sub 2}O in vesicles and implanted H{sub 2} and He in irradiated mineral and glass grains.

  14. Implications of extraterrestrial material on the origin of life

    Science.gov (United States)

    Pasek, Matthew

    2015-08-01

    Stanley Miller's discovery of an abiotic organic synthesis relevant to the early earth provided a route to the scientific consideration of the origin of life. Since the 1950s, several thousands of experiments have shown that the precursor molecules to living biochemical systems could come about naturally. That these processes are active in the universe has been demonstrated by the detection of organic molecules in chondritic meteorites. Indeed, the very delivery of organics by extraterrestrial material may have been a viable source of important prebiotic molecules on the early earth. In this talk I will review the delivery of organics and other elements to the early earth, and will attempt to quantify the mass of material that might have been present from extraterrestrial sources on the early earth.The flux of prebiotic material on the early earth was influenced by the increase in delivery in the early history of the solar system, and by the sources available in the early solar system. Carbonaceous asteroids, comets, stony chondritic bodies, and differentiated asteroids each would have provided different materials to the early earth. The atmosphere would have provided a filter for some of this material, and the amount that reached the earth's surface would have depended on material strength, angle of entry, and atmospheric composition.Previously I reported that carbonaceous chondrites and micrometeorites would have provided a diffuse source of organic molecules on the early earth, whereas differentiated asteroids would have provided concentrated point sources for other materials, such as phosphorus (Pasek and Lauretta, Origins of Life and Evolution of Biospheres 2008). These results are reconsidered in the light of new ideas on the bombardment history of the early solar system, and with new considerations of the composition of source material that reached the earth.

  15. 基于GARCH-EVT-Copula的社保基金投资组合风险测度研究

    Institute of Scientific and Technical Information of China (English)

    江红莉; 何建敏; 庄亚明

    2011-01-01

    社保基金是社会保障事业健康发展的物质基础,安全性是其投资的首要原则.文章基于GARCH-EVT-Copula方法测度了社保基金投资组合的VaR.首先,基于GARCH、EVT对投资组合中各金融资产收益的边缘分布建模,然后,采用极大似然估计法和Bootstrap方法估计尾部的分布函数,接着,基于Copula方法研究组合中金融资产间的相关结构,最后,运用Monte Carlo方法测度投资组合的VaR.Kupiec检验表明,基于GARCH-EVT-Copula模型测度社保基金投资组合的风险是合适的.

  16. Modeling Speed Limit Offenders in Mauritius Using Symmetric and Asymmetric GARCH Models: From Financial Modeling to Traffic Modeling

    Directory of Open Access Journals (Sweden)

    Indranarain Ramlall

    2012-06-01

    Full Text Available Many countries have adopted important policies in view of curbing the number of injuries/fatal road accidents with the most important being speed limit enforcement. In that respect, Mauritius has recently embarked on a strategy of using cameras in view of detecting violations to speed limits. However, the empirical literature on speed limit offenders is still very poor in terms of modeling. In essence, this paper constitutes the very first study that provides sound econometric modeling for speed limit offenders. Findings suggest that vanilla GARCH can be used to model the number of speed limit offenders. Above all, leverage effects are also noted, clearly showing the importance of the type of traffic flow of speed limit offenders which underpins the non-compliance/breach to speed limits. Furthermore, results show the presence of strong weekend effects as confirmed by the dummy variable. The research is expected to provide a momentum in the use of GARCH models for traffic modeling not only for Mauritius but also for other countries in the world.

  17. Curating NASA's Future Extraterrestrial Sample Collections: How Do We Achieve Maximum Proficiency?

    Science.gov (United States)

    McCubbin, Francis; Evans, Cynthia; Zeigler, Ryan; Allton, Judith; Fries, Marc; Righter, Kevin; Zolensky, Michael

    2016-01-01

    The Astromaterials Acquisition and Curation Office (henceforth referred to herein as NASA Curation Office) at NASA Johnson Space Center (JSC) is responsible for curating all of NASA's extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10E "Curation of Extraterrestrial Materials", JSC is charged with "The curation of all extraterrestrial material under NASA control, including future NASA missions." The Directive goes on to define Curation as including "... documentation, preservation, preparation, and distribution of samples for research, education, and public outreach." Here we describe some of the ongoing efforts to ensure that the future activities of the NASA Curation Office are working towards a state of maximum proficiency.

  18. the Ĝ infrared search for extraterrestrial civilizations with large energy supplies. II. Framework, strategy, and first result

    Energy Technology Data Exchange (ETDEWEB)

    Wright, J. T.; Griffith, R. L.; Sigurdsson, S. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA, 16802 (United States); Povich, M. S. [Department of Physics and Astronomy, California State Polytechnic University, Pomona, 3801 West Temple Avenue, Pomona, CA 91768 (United States); Mullan, B. [Blue Marble Space Institution of Science, P.O. Box 85561, Seattle, WA 98145-1561 (United States)

    2014-09-01

    We describe the framework and strategy of the Ĝ infrared search for extraterrestrial civilizations with large energy supplies, which will use the wide-field infrared surveys of WISE and Spitzer to search for these civilizations' waste heat. We develop a formalism for translating mid-infrared photometry into quantitative upper limits on extraterrestrial energy supplies. We discuss the likely sources of false positives, how dust can and will contaminate our search, and prospects for distinguishing dust from alien waste heat. We argue that galaxy-spanning civilizations may be easier to distinguish from natural sources than circumstellar civilizations (i.e., Dyson spheres), although GAIA will significantly improve our capability to identify the latter. We present a zeroth order null result of our search based on the WISE all-sky catalog: we show, for the first time, that Kardashev Type III civilizations (as Kardashev originally defined them) are very rare in the local universe. More sophisticated searches can extend our methodology to smaller waste heat luminosities, and potentially entirely rule out (or detect) both Kardashev Type III civilizations and new physics that allows for unlimited 'free' energy generation.

  19. Miniature Time of Flight Mass Spectrometer for Space and Extraterrestrial Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The PI has developed a miniature time-of-flight mass spectrometer (TOF-MS), which can be op-timized for space and extraterrestrial applications, by using a...

  20. Signal coverage approach to the detection probability of hypothetical extraterrestrial emitters in the Milky Way

    Science.gov (United States)

    Grimaldi, Claudio

    2017-04-01

    The lack of evidence for the existence of extraterrestrial life, even the simplest forms of animal life, makes it is difficult to decide whether the search for extraterrestrial intelligence (SETI) is more a high-risk, high-payoff endeavor than a futile attempt. Here we insist that even if extraterrestrial civilizations do exist and communicate, the likelihood of detecting their signals crucially depends on whether the Earth lies within a region of the galaxy covered by such signals. By considering possible populations of independent emitters in the galaxy, we build a statistical model of the domain covered by hypothetical extraterrestrial signals to derive the detection probability that the Earth is within such a domain. We show that for general distributions of the signal longevity and directionality, the mean number of detectable emitters is less than one even for detection probabilities as large as 50%, regardless of the number of emitters in the galaxy.

  1. Defining a Need for Assessing the Extraterrestrial Environmental Impacts of Lunar Activities

    Science.gov (United States)

    Kramer, W. R.

    2016-11-01

    Protocols guiding an extraterrestrial environmental impact assessment process are warranted. Industry-developed and -managed standards and an environmental code of conduct based, in part, on best management practices are proposed.

  2. 不同GARCH模型对股市风险价值评价的比较研究%The Calculation of VaR in Stock Market Based on Garch Type Models Comparison

    Institute of Scientific and Technical Information of China (English)

    侍成; 赵行为

    2016-01-01

    VaR (value at risk)is a widely-used standard to measure risks in the financial market.By working out four GARCH type models(GARCH-t;EGARCH-t;GJR-GARCH-t;Beta-Skew-t-EGARCH),an empirical study is made of a se-ries of features concerning the logarithmic Return Rate of the four models,and a Kupiec test is then made to verify the VaRs results so as to find out about which model fits best in the reality.%通过给出了四种 GARCH 模型(GARCH-t、EGARCH-t、GJR-GARCHt、Beta-Skew-t-EGARCH),进而实例研究了对数收益率序列的一系列特征,计算了基于不同 GARCH 模型下的风险价值,并对计算出的风险价值进行了Kupiec检验。通过比较发现GJR-GARCH-t模型计算VaR更为准确,而Bata-Skew-t-EGARCH 模型对股市反应较为敏感,在计算 VaR上也有一定的优越性。

  3. Radio Searches for Signatures of Advanced Extraterrestrial Life

    Science.gov (United States)

    Siemion, Andrew

    Over the last several decades, observational astronomy has produced a flood of discoveries that suggest that the building blocks and circumstances that gave rise to life on Earth may be the rule rather than the exception. It has now been conclusively shown that planets are common and that some 5-15% of FGKM stars host planets existing in their host star's habitable zone. Further, terrestrial biology has demonstrated that life on our own planet can thrive in extraordinarily extreme environments, dramatically extending our notion of what constitutes habitability. The deeper question, yet unanswered, is whether or not life in any form has ever existed in an environment outside of the Earth. As humans, we are drawn to an even more profound question, that of whether or not extraterrestrial life may have evolved a curiosity about the universe similar to our own and the technology with which to explore it. Radio astronomy has long played a prominent role in searches for extraterrestrial intelligence (SETI), beginning with the first suggestions by Cocconi and Morrison (1959) that narrow-band radio signals near 1420 MHz might be effective tracers of advanced technology and early experiments along these lines by Frank Drake in 1961, continuing through to more recent investigations searching for several types of coherent radio signals indicative of technology at a wider range of frequencies. The motivations for radio searches for extraterrestrial intelligence have been throughly discussed in the literature, but the salient arguments are the following: 1. coherent radio emission is commonly produced by advanced technology (judging by Earth’s technological development), 2. electromagnetic radiation can convey information at the maximum velocity currently known to be possible, 3. radio photons are energetically cheap to produce, 4. certain types of coherent radio emissions are easily distinguished from astrophysical background sources, especially within the so

  4. Risk Measurement of Open-end Funds Portfolio of China Based on Copula-GARCH-EVT Model%基于Copula-GARCH-EVT的中国开放式基金投资组合风险度量

    Institute of Scientific and Technical Information of China (English)

    杨湘豫; 崔迎媛

    2009-01-01

    文章结合CARCH模型和EVT理论刻画了单个金融资产收益率的波动性和尾部分布,并将Copula函数和Monte Carlo技术应用于证券投资组合的VaR计算方法.通过对光大红利基金的实证研究,得到前十大重仓中单只股票及其投资组合的风险值,结果表明,基于Copula-GARCH-EVT的VaR方法具有重要的经济应用价值.

  5. International law implications of the detection of extraterrestrial intelligent signals

    Science.gov (United States)

    Kopal, Vladimir

    This paper first considers whether the present law of outer space, as it has been enshrined in five United Nations treaties and other legal documents concerning outer space, provides a satisfactory basis for SETI/CETI activities. In the author's opinion, these activities may serve "the common interest of all mankind in the progress of the exploration and use of outer space for peaceful purposes," as recognized in the 1967 Outer Space Treaty. The use of the radio frequency spectrum for SETI/CETI purposes should be in conformity with the legal principles governing this valuable natural resource, as expressed in the International Telecommunication Convention and related documents, and with allocations of the relevant segments of the spectrum by the competent bodies of the International Telecommunication Union. In the second part the author examines the impact that the detection of extraterrestrial intelligent signals may have on the present body of space law. A possible role for the United Nations in this respect is also explored and a timely interest of the world body in discussing questions relating to this subject is recommended. Consideration of these questions could become a tool helping to concentrate the attention of the world community on problems of common concern and thus to strengthen international cooperation. However, the author believes that a law-making process that would aim at elaborating a special regulation of activities in this field would be premature at this stage. It should be initiated only when the boundary between possibilities and realities is crossed. Finally, the paper outlines some likely transformation in our space law thinking that would be the consequence of the detection of extraterrestrial intelligent signals. Elaboration of the principles and norms to govern relations between the international community of our own planet and other intelligent communities in the universe would add a new dimension to the present body of outer space

  6. The Search for Extraterrestrial Intelligence in Earth's Solar Transit Zone.

    Science.gov (United States)

    Heller, René; Pudritz, Ralph E

    2016-04-01

    Over the past few years, astronomers have detected thousands of planets and candidate planets by observing their periodic transits in front of their host stars. A related method, called transit spectroscopy, might soon allow studies of the chemical imprints of life in extrasolar planetary atmospheres. Here, we address the reciprocal question, namely, from where is Earth detectable by extrasolar observers using similar methods. We explore Earth's transit zone (ETZ), the projection of a band around Earth's ecliptic onto the celestial plane, where observers can detect Earth transits across the Sun. ETZ is between 0.520° and 0.537° wide due to the noncircular Earth orbit. The restricted Earth transit zone (rETZ), where Earth transits the Sun less than 0.5 solar radii from its center, is about 0.262° wide. We first compile a target list of 45 K and 37 G dwarf stars inside the rETZ and within 1 kpc (about 3260 light-years) using the Hipparcos catalogue. We then greatly enlarge the number of potential targets by constructing an analytic galactic disk model and find that about 10(5) K and G dwarf stars should reside within the rETZ. The ongoing Gaia space mission can potentially discover all G dwarfs among them (several 10(4)) within the next 5 years. Many more potentially habitable planets orbit dim, unknown M stars in ETZ and other stars that traversed ETZ thousands of years ago. If any of these planets host intelligent observers, they could have identified Earth as a habitable, or even as a living, world long ago, and we could be receiving their broadcasts today. The K2 mission, the Allen Telescope Array, the upcoming Square Kilometer Array, or the Green Bank Telescope might detect such deliberate extraterrestrial messages. Ultimately, ETZ would be an ideal region to be monitored by the Breakthrough Listen Initiatives, an upcoming survey that will constitute the most comprehensive search for extraterrestrial intelligence so far.

  7. Supporting Research and Technology Activities for a Microwave Observing Program to Search for Extraterrestrial Intelligence

    Science.gov (United States)

    Tarter, Jill; Backus, Peter

    1995-01-01

    Curriculum materials based on the search for extraterrestrial intelligence (SETI) were developed for grades 3 through 9 science classes. The project was supported in part by NASA. Six teacher's guides, plus ancillary visuals, addressing topics in astronomy, biology, chemistry, geosciences, and physics as well as mathematics, social sciences, and language arts, were designed by a team of teachers, scientists. curriculum developers, and artists. First drafts were piloted by 10 design team teachers; revised drafts were field tested by 109 teachers in 30 states. Extensive feedback from these teachers and their students and reviews by scientists were used to revise materials prior to submission to the publisher. The field test teachers overall ranking of all guides (data from individual lesson feedback forms) was 431 on a one low to five high scale; 85% found the content appropriate to course and grade level and 75% indicated they had no reservations about using the materials again or recommending them to colleagues. The ratio of liked to disliked student responses (from 1305 student letters) was 70:30. Most recommendations from the teachers, students, and science reviewers were incorporated in the final versions for the guides, published by Libraries Unlimited/Teacher Ideas Press, 1995.

  8. 基于GARCH-EVT模型的人民币汇率风险测度研究

    Institute of Scientific and Technical Information of China (English)

    王宗润; 周艳菊

    2010-01-01

    考虑到金融资产收益序列的时变性和厚尾性,本文采用GARCH模型和EVT模型相结合的方法研究人民币汇率风险测度,求出了相应置信水平下的汇率风险值.返回检验的结果表明,基于GARCH-EVT模型的人民币汇率风险方法要明显优于传统的历史模拟法和极值理论方法,而且在低置信水平下,用条件在险值CVaR来预测汇率风险值会得到更准确的结果.

  9. Fuel prices scenario generation based on a multivariate GARCH model for risk analysis in a wholesale electricity market

    Energy Technology Data Exchange (ETDEWEB)

    Batlle, C.; Barquin, J. [Universidad Pontifica Comillas, Madrid (Spain). Instituto de Investigacion Tecnologica

    2004-05-01

    This paper presents a fuel prices scenario generator in the frame of a simulation tool developed to support risk analysis in a competitive electricity environment. The tool feeds different erogenous risk factors to a wholesale electricity market model to perform a statistical analysis of the results. As the different fuel series that are studied, such as the oil or gas ones, present stochastic volatility and strong correlation among them, a multivariate Generalized Autoregressive Conditional Heteroskedastic (GARCH) model has been designed in order to allow the generation of future fuel prices paths. The model makes use of a decomposition method to simplify the consideration of the multidimensional conditional covariance. An example of its application with real data is also presented. (author)

  10. Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina

    Directory of Open Access Journals (Sweden)

    M.J. Orgeira

    2017-01-01

    Full Text Available The Quaternary infilling of a circular structure located in Bajada del Diablo, Chubut Province, Argentina has been proposed as a crater strewn field in previous studies. Here we report the finding of about 65 microspherules collected in a trench excavated in the center of the structure. The majority of hand-picked specimens are single, but some of them exhibit compound forms. The single specimens are spherical with a mean size of 137 μm, whereas the more complex samples show peduncles and drop shapes. Dendritic crystal growth is recognized in the internal structure of some broken microspherules. Preliminary chemical composition from the surface and center of microspherules was determined by energy dispersive spectrometry employing EDS. Quantitative EMPA and XRD analysis indicate that the microspherules are mainly composed of Fe and O with magnetite, Fe0 with subordinate wüstite. Following consideration of possible anthropogenic and volcanic origins, these spherulites are ascribed to an extraterrestrial input. An accumulation rate of 47 microspherules per m2/yr is estimated for the studied sediments. This value is two orders of magnitude higher than the reference flux for cosmic dust estimated for the last 1 Ma in the Transantarctic Mountains. The microspherules might have been generated as a byproduct of asteroid entry in the atmosphere.

  11. Carbonaceous Meteorites Contain a Wide Range of Extraterrestrial Nucleobases

    Science.gov (United States)

    Callahan, Michael P.; Smith, Karen E.; Cleaves, H. James, II; Ruzicka, Josef; Stern, Jennifer C.; Glavin, Daniel P.; House, Christopher H.; Dworkin, Jason P.

    2011-01-01

    All terrestrial organisms depend on nucleic acids (RNA and DNA), which use pyrimidine and purine nucleobases to encode genetic information. Carbon-rich meteorites may have been important sources of organic compounds required for the emergence of life on the early Earth; however, the origin and formation of nuc1eobases in meteorites has been debated for over 50 y. So far, the few nuc1eobases reported in meteorites are biologically common and lacked the structural diversity typical of other indigenous meteoritic organics. Here, we investigated the abundance and distribution of nucleobases and nucleobase analogs in formic acid extracts of 12 different meteorites by liquid chromatography-mass spectrometry. The Murchison and Lonewolf Nunataks 94102 meteorites contained a diverse suite of nucleobases, which included three unusual and terrestrially rare nucleobase analogs; purine, 2,6-diminopurine, and 6,8-diaminopurine. In a parallel experiment, we found an identical suite of nucleobases and nucleobase analogs generated in reactions of ammonium cyanide. Additionally, these nucleobase analoge were not detected above our parts-per-billion detection limits in any of the procedural blanks, control samples, a terrestrial soil sample, and an Antarctic ice sample. Our results demonstrate that the purines detected in meteorites are consistent with products of ammonium cyanide chemistry, which provides a plausible mechanism for their synthesis in the asteroid parent bodies, and strongly supports an extraterrestrial origin. The discovery of new nucleobase analogs in meteorites also expands the prebiotic molecular inventory available for constructing the first genetic molecules.

  12. Extraterrestrial materials examined by mean of nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Khodja, H., E-mail: hicham.khodja@cea.fr [CEA/IRAMIS/SIS2M/LEEL, F-91191 Gif-sur-Yvette (France); CNRS/UMR 3299/SIS2M/LEEL, F-91191 Gif-sur-Yvette (France); Smith, T. [CEA/IRAMIS/SIS2M/LEEL, F-91191 Gif-sur-Yvette (France); CNRS/UMR 3299/SIS2M/LEEL, F-91191 Gif-sur-Yvette (France); Engrand, C. [CSNSM, Bat 104, F-91405, Orsay Campus (France); Herzog, G. [Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854-8087 (United States); Raepsaet, C. [CEA/IRAMIS/SIS2M/LEEL, F-91191 Gif-sur-Yvette (France); CNRS/UMR 3299/SIS2M/LEEL, F-91191 Gif-sur-Yvette (France)

    2013-07-01

    Comet fragments, micrometeorites, and Interplanetary Dust Particles (IDPs) are small objects (<1 mm) of high scientific interest in cosmochemistry. More particularly, the determination of light element concentrations, such as C and N, in cometary samples is of interest since it gives information on the regions where such materials formed. Analyses of such objects should be performed so as to extract as much information as possible while preserving sample integrity. For this purpose, we need instruments and methods that provide both microanalysis and detailed imaging. In these respects, the nuclear microprobe offers many potential advantages: (i) the spatial resolution, ∼1 μm is well-matched to the typical object dimensions, (ii) with some reservations, it is non-destructive when carefully conducted, (iii) it is quantitative, and especially sensitive for light elements. At the Saclay nuclear microprobe, we have been performing analyses of extraterrestrial objects for many years. We review some of these studies, emphasizing the specific requirements for successful analyses. We also discuss the potential pitfalls that may be encountered.

  13. The SERENDIP III 70 cm Search for Extraterrestrial Intelligence

    CERN Document Server

    Bowyer, Stuart; Korpela, Eric; Cobb, Jeff; Lebofsky, Matt; Werthimer, Dan

    2016-01-01

    We employed the SERENDIP III system with the Arecibo radio telescope to search for possible artificial extraterrestrial signals. Over the four years of this search we covered 93% of the sky observable at Arecibo at least once and 44% of the sky five times or more with a sensitivity of ~3E-25 W/m2. The data were sent to a 4 million channel spectrum analyzer. Information was obtained from over 1E+14 independent data points and the results were then analyzed via a suite of pattern detection algorithms to identify narrow band spectral power peaks that were not readily identifiable as the product of human activity. We separately selected data coincident with interesting nearby G dwarf stars that were encountered by chance in our sky survey for suggestions of excess power peaks. The peak power distributions in both these data sets were consistent with random noise. We report upper limits on possible signals from the stars investigated and provide examples of the most interesting candidates identified in the sky sur...

  14. "Gulliver", an experiment for extraterrestrial life detection and analysis.

    Science.gov (United States)

    Levin, G V; Heim, A H; Thompson, M F; Beem, D R; Horowitz, N H

    1964-01-01

    Based on the probability that extraterrestrial life is biochemically somewhat similar to life on Earth, a life detection experiment is being prepared to explore Mars. The experiment will be performed by an automated device which will carry a microbiological medium being developed to support a wide range of earth microorganisms. Selected ingredients of the medium will be labeled with radioactive isotopes. A sticky string, shot out from and reeled back into the device, will gather a sample of the Martian soil. It is hoped the radioactive atoms in the compounds will be metabolized by the unknown organisms in the soil and evolved in a labelled gas. The gas will be collected by a chemical "getter" and the radioactivity measured for transmission to Earth. A positive response from the test unit and a negative, or lesser, response from a poisoned control unit would constitute evidence of life. The device can also differentiate between photosynthetic and nonphotosynthetic metabolic activity. Data from field tests on Earth are presented.

  15. Designing Extraterrestrial Plant Growth Habitats with Low Pressure Atmospheres

    Science.gov (United States)

    Corey, Kenneth A.

    2002-01-01

    In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

  16. Philosophy and problems of the definition of Extraterrestrial Life

    CERN Document Server

    Schneider, Jean

    2011-01-01

    When we try to search for extraterrestrial life and intelligence, we have to follow some guidelines. The first step is to clarify what is to be meant by "Life" and "intelligence", i.e. an attempt to define these words. The word "definition" refers to two different situations. First, it means an arbitrary convention. On the other hand it also often designates an attempt to clarify the content of a pre-existing word for which we have some spontaneous preconceptions, whatever their grounds, and to catch an (illusory) "essence" of what is defined. It is then made use of pre-existing plain language words which carry an a priori pre-scientific content likely to introduce some confusion in the reader's mind. The complexity of the problem will be analyzed and we will show that some philosophical prejudice is unavoidable. There are two types of philosophy: "Natural Philosophy", seeking for some essence of things, and "Critical (or analytical) Philosophy", devoted to the analysis of the procedures by which we claim to ...

  17. The quest for extraterrestrial life: what about the viruses?

    Science.gov (United States)

    Griffin, Dale Warren

    2013-08-01

    Recently, viruses have been recognized as the most numerous entities and the primary drivers of evolution on Earth. Historically, viruses have been mostly ignored in the field of astrobiology due to the view that they are not alive in the classical sense and if encountered would not present risk due to their host-specific nature. What we currently know of viruses is that we are most likely to encounter them on other life-bearing planets; that while some are exquisitely host-specific, many viruses can utilize hundreds of different host species; that viruses are known to exist in our planet's most extreme environments; and that while many do not survive long outside their hosts, some can survive for extended periods, especially in the cold. In our quest for extraterrestrial life, we should be looking for viruses; and while any encountered may pose no risk, the possibility of an encounter with a virus capable of accessing multiple cell types exists, and any prospective contact with such an organism should be treated accordingly.

  18. Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases.

    Science.gov (United States)

    Callahan, Michael P; Smith, Karen E; Cleaves, H James; Ruzicka, Josef; Stern, Jennifer C; Glavin, Daniel P; House, Christopher H; Dworkin, Jason P

    2011-08-23

    All terrestrial organisms depend on nucleic acids (RNA and DNA), which use pyrimidine and purine nucleobases to encode genetic information. Carbon-rich meteorites may have been important sources of organic compounds required for the emergence of life on the early Earth; however, the origin and formation of nucleobases in meteorites has been debated for over 50 y. So far, the few nucleobases reported in meteorites are biologically common and lacked the structural diversity typical of other indigenous meteoritic organics. Here, we investigated the abundance and distribution of nucleobases and nucleobase analogs in formic acid extracts of 12 different meteorites by liquid chromatography-mass spectrometry. The Murchison and Lonewolf Nunataks 94102 meteorites contained a diverse suite of nucleobases, which included three unusual and terrestrially rare nucleobase analogs: purine, 2,6-diaminopurine, and 6,8-diaminopurine. In a parallel experiment, we found an identical suite of nucleobases and nucleobase analogs generated in reactions of ammonium cyanide. Additionally, these nucleobase analogs were not detected above our parts-per-billion detection limits in any of the procedural blanks, control samples, a terrestrial soil sample, and an Antarctic ice sample. Our results demonstrate that the purines detected in meteorites are consistent with products of ammonium cyanide chemistry, which provides a plausible mechanism for their synthesis in the asteroid parent bodies, and strongly supports an extraterrestrial origin. The discovery of new nucleobase analogs in meteorites also expands the prebiotic molecular inventory available for constructing the first genetic molecules.

  19. Factors affecting production rates of cosmogenic nuclides in extraterrestrial matter

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, R.C., E-mail: reedy@psi.edu

    2015-10-15

    Good production rates are needed for cosmic-ray-produced nuclides to interpret their measurements. Rates depend on many factors, especially the pre-atmospheric object’s size, the location of the sample in that object (such as near surface or deep inside), and the object’s bulk composition. The bulk composition affects rates, especially in objects with very low and very high iron contents. Extraterrestrial materials with high iron contents usually have higher rates for making nuclides made by reactions with energetic particles and lower rates for the capture of thermal neutrons. In small objects and near the surface of objects, the cascade of secondary neutrons is being developed as primary particles are being removed. Deep in large objects, that secondary cascade is fully developed and the fluxes of primary particles are low. Recent work shows that even the shape of an object in space has a small but measureable effect. Work has been done and continues to be done on better understanding those and other factors. More good sets of measurements in meteorites with known exposure geometries in space are needed. With the use of modern Monte Carlo codes for the production and transport of particles, the nature of these effects have been and is being studied. Work needs to be done to improve the results of these calculations, especially the cross sections for making spallogenic nuclides.

  20. Searching for Extraterrestrial Intelligence with the Square Kilometre Array

    CERN Document Server

    Siemion, Andrew P V; Cheng-Jin, Jin; Chennamangalam, Jayanth; Cordes, James; DeBoer, David R; Falcke, Heino; Garrett, Mike; Garrington, Simon; Gurvits, Leonid; Hoare, Melvin; Korpela, Eric J; Lazio, Joseph; Messerschmitt, David; Morrison, Ian S; O'Brien, Tim; Paragi, Zsolt; Penny, Alan; Spitler, Laura; Tarter, Jill; Werthimer, Dan

    2014-01-01

    The vast collecting area of the Square Kilometre Array (SKA), harnessed by sensitive receivers, flexible digital electronics and increased computational capacity, could permit the most sensitive and exhaustive search for technologically-produced radio emission from advanced extraterrestrial intelligence (SETI) ever performed. For example, SKA1-MID will be capable of detecting a source roughly analogous to terrestrial high-power radars (e.g. air route surveillance or ballistic missile warning radars, EIRP (EIRP = equivalent isotropic radiated power, ~10^17 erg sec^-1) at 10 pc in less than 15 minutes, and with a modest four beam SETI observing system could, in one minute, search every star in the primary beam out to ~100 pc for radio emission comparable to that emitted by the Arecibo Planetary Radar (EIRP ~2 x 10^20 erg sec^-1). The flexibility of the signal detection systems used for SETI searches with the SKA will allow new algorithms to be employed that will provide sensitivity to a much wider variety of si...

  1. Astrobiology in culture: the search for extraterrestrial life as "science".

    Science.gov (United States)

    Billings, Linda

    2012-10-01

    This analysis examines the social construction of authority, credibility, and legitimacy for exobiology/astrobiology and, in comparison, the search for extraterrestrial intelligence (SETI), considering English-language conceptions of these endeavors in scientific culture and popular culture primarily in the United States. The questions that define astrobiology as a scientific endeavor are multidisciplinary in nature, and this endeavor is broadly appealing to public audiences as well as to the scientific community. Thus, it is useful to examine astrobiology in culture-in scientific culture, official culture, and popular culture. A researcher may explore science in culture, science as culture, by analyzing its rhetoric, the primary means that people use to construct their social realities-their cultural environment, as it were. This analysis follows this path, considering scientific and public interest in astrobiology and SETI and focusing on scientific and official constructions of the two endeavors. This analysis will also consider whether and how scientific and public conceptions of astrobiology and SETI, which are related but at the same time separate endeavors, converge or diverge and whether and how these convergences or divergences affect the scientific authority, credibility, and legitimacy of these endeavors.

  2. PHYSICS

    CERN Multimedia

    P. Sphicas

    There have been three physics meetings since the last CMS week: “physics days” on March 27-29, the Physics/ Trigger week on April 23-27 and the most recent physics days on May 22-24. The main purpose of the March physics days was to finalize the list of “2007 analyses”, i.e. the few topics that the physics groups will concentrate on for the rest of this calendar year. The idea is to carry out a full physics exercise, with CMSSW, for select physics channels which test key features of the physics objects, or represent potential “day 1” physics topics that need to be addressed in advance. The list of these analyses was indeed completed and presented in the plenary meetings. As always, a significant amount of time was also spent in reviewing the status of the physics objects (reconstruction) as well as their usage in the High-Level Trigger (HLT). The major event of the past three months was the first “Physics/Trigger week” in Apri...

  3. PHYSICS

    CERN Multimedia

    D. Acosta

    2010-01-01

    A remarkable amount of progress has been made in Physics since the last CMS Week in June given the exponential growth in the delivered LHC luminosity. The first major milestone was the delivery of a variety of results to the ICHEP international conference held in Paris this July. For this conference, CMS prepared 15 Physics Analysis Summaries on physics objects and 22 Summaries on new and interesting physics measurements that exploited the luminosity recorded by the CMS detector. The challenge was incorporating the largest batch of luminosity that was delivered only days before the conference (300 nb-1 total). The physics covered from this initial running period spanned hadron production measurements, jet production and properties, electroweak vector boson production, and even glimpses of the top quark. Since then, the accumulated integrated luminosity has increased by a factor of more than 100, and all groups have been working tremendously hard on analysing this dataset. The September Physics Week was held ...

  4. Search for Extraterrestrial Osmium at the Allerod - Younger Dryas Boundary

    Science.gov (United States)

    Beets, C.; Sharma, M.; Kasse, K.; Bohncke, S.

    2008-12-01

    Ir and Os are excellent markers of extraterrestrial impact events, due to their high abundance in ET objects (Alvarez et al., 1980 Science; Turekian, 1982 Geol. Bull. Am. Spec. Pap.). Os has the advantage over Ir, in that the 187Os/188Os ratio also greatly differs between meteorites and upper continental crust (UCC). The combination of [Os] and 187Os/188Os analyses would be superior in detecting any ET contribution. Firestone et al (2007 PNAS) attributed a widespread 12.9 ka Ir containing black carbon layer to a potential extraterrestrial impact at the Allerød-Younger Dryas (A-YD) boundary. In order to test this inference, we measured [Os] and 187Os/188Os on a radiocarbon dated A-YD record (13.210 to 12.788 cal years BP) from the Netherlands. This location is close to Lommel, a Belgian site studied by Firestone et al.(2007). The organic-rich sequence was sampled continuously over a 12 cm interval at 2 cm resolution (~70 years). About 10 g samples were freeze-dried, ground and homogenized in a zirconia ball-mill. The samples mixed with 190Os tracer solutions were dissolved in carius tubes and Os extracted in liquid bromine. Os was further purified using micro-distillation. Os isotopes were measured using N-TIMS on Dartmouth Triton. The procedural blank was 7 fg/g Os with an isotopic composition of 0.41±0.01 The Allerød samples have an order of magnitude higher abundance than UCC (200 vs. 30 pg/g), but similar 187Os/188Os ratios, >1.1. The sample at the base of the YD (12.893±75 cal years BP) contains a similar amount of Os, but has a distinctly lower isotopic signature, 0.53±0.002. The high [Os] in the A-YD section possibly reflects enrichment by preferential partitioning into organic matter. The Os isotope composition of 0.53, sandwiched between values >1.1, implies contribution of a significant amount of non-radiogenic Os. Since the pollen spectra show no reworking, the non-radiogenic Os could only have been delivered as a discrete pulse at 12.893 cal yr BP

  5. PHYSICS

    CERN Multimedia

    J. Incandela

    There have been numerous developments in the physics area since the September CMS week. The biggest single event was the Physics/Trigger week in the end of Octo¬ber, whereas in terms of ongoing activities the “2007 analyses” went into high gear. This was in parallel with participation in CSA07 by the physics groups. On the or¬ganizational side, the new conveners of the physics groups have been selected, and a new database for man¬aging physics analyses has been deployed. Physics/Trigger week The second Physics-Trigger week of 2007 took place during the week of October 22-26. The first half of the week was dedicated to working group meetings. The ple¬nary Joint Physics-Trigger meeting took place on Wednesday afternoon and focused on the activities of the new Trigger Studies Group (TSG) and trigger monitoring. Both the Physics and Trigger organizations are now focused on readiness for early data-taking. Thus, early trigger tables and preparations for calibr...

  6. PHYSICS

    CERN Multimedia

    P. Sphicas

    The CPT project came to an end in December 2006 and its original scope is now shared among three new areas, namely Computing, Offline and Physics. In the physics area the basic change with respect to the previous system (where the PRS groups were charged with detector and physics object reconstruction and physics analysis) was the split of the detector PRS groups (the old ECAL-egamma, HCAL-jetMET, Tracker-btau and Muons) into two groups each: a Detector Performance Group (DPG) and a Physics Object Group. The DPGs are now led by the Commissioning and Run Coordinator deputy (Darin Acosta) and will appear in the correspond¬ing column in CMS bulletins. On the physics side, the physics object groups are charged with the reconstruction of physics objects, the tuning of the simulation (in collaboration with the DPGs) to reproduce the data, the provision of code for the High-Level Trigger, the optimization of the algorithms involved for the different physics analyses (in collaboration with the analysis gr...

  7. The forthcoming EISCAT 3D as an extraterrestrial matter monitor

    Science.gov (United States)

    Pellinen-Wannberg, A.; Kero, J.; Mann, I.; Tjulin, A.

    2014-07-01

    High Power Large Aperture (HPLA) radars such as the tristatic EISCAT UHF combined with the EISCAT VHF have been versatile instruments for studying many properties of the meteoroid population even though not designed for the purpose. The future EISCAT 3D facility can become in many aspects orders of magnitude better for observing the extra-terrestrial matter. Whereas the overall science theme with atmospheric radars is to study how the Earth's atmosphere is coupled to space, meeting the requirements for meteor studies is one of the design goals phrased from the user community. The radar will comprise a phased-array transmitter and several phased-array receivers around Northern Scandinavia. It will work at 233 MHz centre frequency with a power of up to 10 MW and run an advanced signal-processing system. Its measurement techniques have never been combined in one radar system: volumetric-, aperture synthesis- and multistatic imaging and adaptive experiments. The volumetric imaging will increase the observing volumes, the interferometry improve the spatial resolution and orbit determinations. These are important issues for studying filaments in the meteor showers, to compute the dust flux in the Earth's vicinity and to estimate the ejection time of meteoroids accurately for theoretical evolution modelling. Investigations using the 233 MHz VHF frequency will provide higher rates than for example the earlier EISCAT UHF. In addition, the new system will observe a larger volume in space and offers the opportunity for longer observation runs up to continuous monitoring. We give a review of how all these new functions will improve the HPLA radar meteor observations.

  8. Applying Biomimetic Algorithms for Extra-Terrestrial Habitat Generation

    Science.gov (United States)

    Birge, Brian

    2012-01-01

    The objective is to simulate and optimize distributed cooperation among a network of robots tasked with cooperative excavation on an extra-terrestrial surface. Additionally to examine the concept of directed Emergence among a group of limited artificially intelligent agents. Emergence is the concept of achieving complex results from very simple rules or interactions. For example, in a termite mound each individual termite does not carry a blueprint of how to make their home in a global sense, but their interactions based strictly on local desires create a complex superstructure. Leveraging this Emergence concept applied to a simulation of cooperative agents (robots) will allow an examination of the success of non-directed group strategy achieving specific results. Specifically the simulation will be a testbed to evaluate population based robotic exploration and cooperative strategies while leveraging the evolutionary teamwork approach in the face of uncertainty about the environment and partial loss of sensors. Checking against a cost function and 'social' constraints will optimize cooperation when excavating a simulated tunnel. Agents will act locally with non-local results. The rules by which the simulated robots interact will be optimized to the simplest possible for the desired result, leveraging Emergence. Sensor malfunction and line of sight issues will be incorporated into the simulation. This approach falls under Swarm Robotics, a subset of robot control concerned with finding ways to control large groups of robots. Swarm Robotics often contains biologically inspired approaches, research comes from social insect observation but also data from among groups of herding, schooling, and flocking animals. Biomimetic algorithms applied to manned space exploration is the method under consideration for further study.

  9. The role of extraterrestrial particles in the formation of the ozone hole

    Energy Technology Data Exchange (ETDEWEB)

    Rosinski, J. [Ferrara Univ., Ferrara (Italy). Dipt. di Fisica; Kerrigan, T.C. [Intel Corporation, EY2-E3, Hillsboro, OR (United States)

    2001-12-01

    The object of Part I of this paper is to estimate the concentration of extraterrestrial particles in the ozone layer over South Pole, Antarctica, during zone hole formation. This estimate is based on an analysis of microscopic magnetic spherules collected in an extended program of atmospheric sampling. Spherules are shown to be of extraterrestrial origin and serve as markers for the larger class of less distinguished extraterrestrial particles. These particles settle to ground level as aggregates formed in a stratospheric ice crystal coalescence process. Specific spherules arrivals at ground level are strongly associated with apparent ozone depletion episodes during formation of the ozone hole. The origin of these spherules is a major stream of extraterrestrial particles independent of known meteor showers. The variability in its intensity from year to year corresponds to the variability in ozone depletion in the ozone hole itself. A quantitative theory based on these spherules arrivals and this coalescence process implies that the concentration of extraterrestrial particles at ozone hole formation lies between 500 and 2000/m{sup 3}. A mechanism is proposed in Part II of this paper by which particle concentrations in this range are sufficient to produce the ozone hole.

  10. No evidence of extraterrestrial noble metal and helium anomalies at Marinoan glacial termination

    Science.gov (United States)

    Peucker-Ehrenbrink, Bernhard; Waters, Christine A.; Kurz, Mark D.; Hoffman, Paul F.

    2016-03-01

    High concentrations of extraterrestrial iridium have been reported in terminal Sturtian and Marinoan glacial marine sediments and are used to argue for long (likely 3-12 Myr) durations of these Cryogenian glaciations. Reanalysis of the Marinoan sedimentary rocks used in the original study, supplemented by sedimentary rocks from additional terminal Marinoan sections, however, does not confirm the initial report. New platinum group element concentrations, and 187Os/188Os and 3He/4He signatures are consistent with crustal origin and minimal extraterrestrial contributions. The discrepancy is likely caused by different sample masses used in the two studies, with this study being based on much larger samples that better capture the stochastic distribution of extraterrestrial particles in marine sediments. Strong enrichment of redox-sensitive elements, particularly rhenium, up-section in the basal postglacial cap carbonates, may indicate a return to more fully oxygenated seawater in the aftermath of the Marinoan snowball earth. Sections dominated by hydrogenous osmium indicate increasing submarine hydrothermal sources and/or continental inputs that are increasingly dominated by young mantle-derived rocks after deglaciation. Sedimentation rate estimates for the basal cap carbonates yield surprisingly slow rates of a few centimeters per thousand years. This study highlights the importance of using sedimentary rock samples that represent sufficiently large area-time products to properly sample extraterrestrial particles representatively, and demonstrates the value of using multiple tracers of extraterrestrial matter.

  11. PHYSICS

    CERN Document Server

    Submitted by

    Physics Week: plenary meeting on physics groups plans for startup (14–15 May 2008) The Physics Objects (POG) and Physics Analysis (PAG) Groups presented their latest developments at the plenary meeting during the Physics Week. In the presentations particular attention was given to startup plans and readiness for data-taking. Many results based on the recent cosmic run were shown. A special Workshop on SUSY, described in a separate section, took place the day before the plenary. At the meeting, we had also two special DPG presentations on “Tracker and Muon alignment with CRAFT” (Ernesto Migliore) and “Calorimeter studies with CRAFT” (Chiara Rovelli). We had also a report from Offline (Andrea Rizzi) and Computing (Markus Klute) on the San Diego Workshop, described elsewhere in this bulletin. Tracking group (Boris Mangano). The level of sophistication of the tracking software increased significantly over the last few months: V0 (K0 and Λ) reconstr...

  12. 基于 GARCH -VaR 模型下对 ETF 基金风险的测度与分析%The Measurement and Analysis of ETF Fund Risk Based on GARCH-VaR Model

    Institute of Scientific and Technical Information of China (English)

    刘降斌; 张洪建; 费洋

    2016-01-01

    ETF fund, also known as the exchange traded index funds (exchange traded funds), is a traded on the stock ex-change , the fund's share of a VaRiable open fund .ETF fund is operated through market signal , replicating the market index for the purpose of using decentralized investment strategy , reducing the systematic risk and the passive investment management and the transaction costs .So that investors benefit from .Taking the SSE 50 index as a sample , a GARCH model is established to calculate the VaR value and actual income rate difference .We try to find out the best selection methods of risk and return , risk measure-ment.The aim is to supervise and control the operation of the fund .%ETF基金又称交易型开放式指数基金(交易所交易基金),是一种在交易所上市交易的、基金份额可变的开放式基金。 ETF基金是通过追踪市场的信号、复制市场指数,采用分散化的投资策略,降低非系统风险的同时又通过被动的投资管理基金,最大限度地降低交易成本,从而使投资者从中获益。试采取上证50指数为样本,从收益的波动性出发,建立GARCH 族模型,计算并分析VaR 值与实际收益率的差别,作为判断风险的依据,为基金管理者、监督者进行基金风险测度、分析和控制提供有效性的参考。

  13. Avaliação da habilidade preditiva entre modelos Garch multivariados : uma análise baseada no critério Model Confidence Set

    OpenAIRE

    Bruna Kasprzak Borges

    2012-01-01

    Esta dissertação analisa a questão da seleção de modelos GARCH multivariados em termos da perfomance de previsão da matriz de covariância condicional. A aplicação empírica é realizada com 7 retornos de índices de ações envolvendo um conjunto de 34 especificações de modelos para os quais computamos as previsões da variância condicional um passo a frente para uma amostra com 60 observações para cada especificação dos modelos GARCH multivariados. A comparação entre os modelos é baseada no proced...

  14. Who owns the Moon? extraterrestrial aspects of land and mineral resources ownership

    CERN Document Server

    Pop, Virgiliu

    2008-01-01

    This work investigates the permissibility and viability of property rights on the celestial bodies, particularly the extraterrestrial aspects of land and mineral resources ownership. In lay terms, it aims to find an answer to the question "Who owns the Moon?" After critically analyzing and dismantling with legal arguments the trivial issue of sale of extraterrestrial real estate, the book addresses the apparent silence of the law in the field of landed property in outer space, scrutinizing whether the factual situation on the extraterrestrial realms calls for legal regulations. The legal status of asteroids and the relationship between appropriation under international law and civil law appropriation are duly examined, as well as different property patterns – such as the commons regime, the Common Heritage of the Mankind, and the Frontier paradigm. Virgiliu Pop is one of world's specialists in the area of space property rights. A member of the International Institute of Space Law, Virgiliu has authored seve...

  15. The Societal Impact of Extraterrestrial Life: The Relevance of History and the Social Sciences

    Science.gov (United States)

    Dick, Steven J.

    This chapter reviews past studies on the societal impact of extraterrestrial life and offers four related ways in which history is relevant to the subject: the history of impact thus far, analogical reasoning, impact studies in other areas of science and technology, and studies on the nature of discovery and exploration. We focus particularly on the promise and peril of analogical arguments, since they are by necessity widespread in the field. This chapter also summarizes the relevance of the social sciences, particularly anthropology and sociology, and concludes by taking a closer look at the possible impact of the discovery of extraterrestrial life on theology and philosophy. In undertaking this study we emphasize three bedrock principles: (1) we cannot predict the future; (2) society is not monolithic, implying many impacts depending on religion, culture and worldview; (3) the impact of any discovery of extraterrestrial life is scenario-dependent.

  16. Fear, pandemonium, equanimity and delight: human responses to extra-terrestrial life.

    Science.gov (United States)

    Harrison, Albert A

    2011-02-13

    How will people respond to the discovery of extra-terrestrial life? Potentially useful resources for addressing this question include historical prototypes, disaster studies and survey research. Reactions will depend on the interplay of the characteristics of the newly found life, the unfolding of the discovery, the context and content of the message and human information processing as shaped by biology, culture and psychology. Pre-existing images of extra-terrestrials as god-like, demonic, or artificial will influence first impressions that may prove highly resistant to change. Most probably people will develop comprehensive images based on minimal information and assess extra-terrestrials in the same ways that they assess one another. Although it is easy to develop frightening scenarios, finding microbial life in our Solar System or intercepting a microwave transmission from many light years away are less likely to be met with adverse reactions such as fear and pandemonium than with positive reactions such as equanimity and delight.

  17. 基于GARCH-EVT-VaR模型的碳市场风险研究--以欧盟为例

    Institute of Scientific and Technical Information of China (English)

    杨翱

    2014-01-01

    本文选取最具代表性的欧盟碳排放权交易体系为研究对象,选用2008年3月3日至2012年12月31日洲际交易所官方网站公布的每日欧盟碳减排配额(EUA)期货市场价格作为分析对象,用 GARCH 模型估计厚尾分布下的EUA日收益率的波动性,并运用极值理论对收益率的尾部进行建模,得到在不同置信水平下有效而准确的VaR估计和ES估计,利用阈值法建立厚尾分布(GED 分布)下GARCH-EVT-VaR动态模型,并对该模型进行返回检验,进一步验证了该模型的准确性。结果表明基于极值理论的GARCH-EVT-VaR模型比传统模型更适合度量厚尾分布下的金融时间序列,是刻画碳市场尾部风险的有效工具。

  18. THE LEVERAGE EFFECT AND THE ASYMMETRY OF THE ERROR DISTRIBUTION IN GARCH-BASED MODELS: THE CASE OF BRAZILIAN MARKET RELATED SERIES

    Directory of Open Access Journals (Sweden)

    Daniel de Almeida

    2014-05-01

    Full Text Available Traditional GARCH models fail to explain at least two of the stylized facts found in financial series: the asymmetry of the distribution of errors and the leverage effect. The leverage effect stems from the fact that losses have a greater influence on future volatilities than do gains. Asymmetry means that the distribution of losses has a heavier tail than the distribution of gains. We test whether these features are present in some series related to the Brazilian market. To test for the presence of these features, the series were fitted by GARCH(1,1, TGARCH(1,1, EGARCH(1,1, and GJR-GARCH(1,1 models with standardized Student t distribution errors with and without asymmetry. Information criteria and statistical tests of the significance of the symmetry and leverage parameters are used to compare the models. The estimates of the VaR (value-at-risk are also used in the comparison. The conclusion is that both stylized facts are present in some series, mostly simultaneously.

  19. Empirical Analysis of Shanghai Stock Exchange Index Based on GARCH Model%基于GARCH模型的上证指数实证分析

    Institute of Scientific and Technical Information of China (English)

    唐俊波; 杨四香; 何树红

    2012-01-01

    在对GARCH模型进行探究的基础上,针对上证指数收益率的波动特征进行GARCH建模,最后通过对所得模型结果的分析得出了我国股市与其他发达国家的股市具有一些共同的地方,即我国的上证指数收益率序列具有显著的异方差特征,且收益率波动的大小与其自身过去的波动大小有非常明显的关系,因此说我国的大盘指数也可以采用GARCH模型来进行拟合和解释。%Based on the research on GARCH Model, GARCH Model is constructed based on the fluctuation of Shanghai Stock Exchange Index earning ratio, the analysis of the results from s Stock Market has characteristics similar to those of developed countries, i the obtained model e. Shanghai Stock shows that China' Exchange earning ratio sequence has significant heteroscedasticity characteristics and the size of earning ratio fluctuations is significantly related to the size of their own past vibrations. Thus, GARCH Model can be used to fit and explain China' s Stock Market Index.

  20. Investment Portfolio Risk Analysis of Gold, Stock and Bond Based on Copula-GARCH Theory%基于 Copula-GARCH 模型的黄金、股票与债券投资组合风险分析

    Institute of Scientific and Technical Information of China (English)

    曹培慎; 武昭; 张静

    2012-01-01

      由于金融危机影响,国际金价强势攀升,黄金已经与股票、债券一样,成为一种非常重要的投资工具.因此,本文基于Copula函数和GARCH模型[1],先建立Copula-GARCH-t模型对黄金、股票以及债券的投资组合风险进行实证研究分析.结果表明,Copula-GARCH-t模型对数据描述较为准确,因而在刻画投资组合风险方面效果较好.再运用蒙特卡洛模拟法,在风险最小情况下,计算出三种资产的投资比例,并计算出资产组合的VaR.%  For the influence of the financial crisis and the continuous rising of gold price, gold has been a very important investment tool together with stock and bond. This paper constructs a Copula-GARCH-t Model based on Copula functions and the GARCH model to make an empirical research on and analysis of the investment portfolio risk of gold, stock and bond. The results show that the Copula-GARCH-t model can make an accurate description of the data, comparatively speaking. Thus it has a good ability to depict the portfolio risk. What’s more, it supplies an investment ratio of the three assets in the case of the minimized risk.

  1. PHYSICS

    CERN Multimedia

    D. Futyan

    A lot has transpired on the “Physics” front since the last CMS Bulletin. The summer was filled with preparations of new Monte Carlo samples based on CMSSW_3, the finalization of all the 10 TeV physics analyses [in total 50 analyses were approved] and the preparations for the Physics Week in Bologna. A couple weeks later, the “October Exercise” commenced and ran through an intense two-week period. The Physics Days in October were packed with a number of topics that are relevant to data taking, in a number of “mini-workshops”: the luminosity measurement, the determination of the beam spot and the measurement of the missing transverse energy (MET) were the three main topics.   Physics Week in Bologna The second physics week in 2009 took place in Bologna, Italy, on the week of Sep 7-11. The aim of the week was to review and establish (we hoped) the readiness of CMS to do physics with the early collisions at the LHC. The agenda of the...

  2. PHYSICS

    CERN Multimedia

    D. Futyan

    A lot has transpired on the “Physics” front since the last CMS Bulletin. The summer was filled with preparations of new Monte Carlo samples based on CMSSW_3, the finalization of all the 10 TeV physics analyses [in total 50 analyses were approved] and the preparations for the Physics Week in Bologna. A couple weeks later, the “October Exercise” commenced and ran through an intense two-week period. The Physics Days in October were packed with a number of topics that are relevant to data taking, in a number of “mini-workshops”: the luminosity measurement, the determination of the beam spot and the measurement of the missing transverse energy (MET) were the three main topics.  Physics Week in Bologna The second physics week in 2009 took place in Bologna, Italy, on the week of Sep 7-11. The aim of the week was to review and establish how ready we are to do physics with the early collisions at the LHC. The agenda of the week was thus pac...

  3. GEOLOGICAL MARKS OF A POSSIBLE EXTRATERRESTRIAL IMPACT EVENT ON THE BOUNDARY BETWEEN SINIAN/CAMBRIAN IN TIANMENSHAN IN WESTERN HUNAN

    Institute of Scientific and Technical Information of China (English)

    HUANG Huaiyong; WANG Daojing; CHEN Guanghao; YIN Hanhui

    2004-01-01

    Geologic marks related to extraterrestrial impact events, such as impact split gravels, impact brecciate layers, impact dikes, microirghizites, microtektites, especially meteoritic residues, were discovered on the boundary between Sinian/Cambrian at Tianmenshan of Western Hunan, which may possibly demonstrate that an extraterrestrial impact event has ever occurred there on the S/C boundary.

  4. Optimum conditions for prebiotic evolution in extraterrestrial environments

    Science.gov (United States)

    Abbas, Ousama H.

    The overall goal of the dissertation was to devise synthetic pathways leading to the production of peptides and amino acids from smaller organic precursors. To this end, eight different zeolites were tested in order to determine their catalytic potential in the conversion of amino acids to peptides. The zeolites tested were either synthetic or naturally occurring. Acidic solutions of amino acids were prepared with or without zeolites and their reactivity was monitored over a four-week time interval. The kinetics and feasibility of peptide synthesis from selected amino acid combinations was investigated via the paper chromatography technique. Nine different amino acids were tested. The nature and extent of product were measured at constant time intervals. It was found that two ZSM-5 synthetic zeolites as well as the Fisher Scientific zeolite mix without alumina salts may have a catalytic potential in the conversion of amino acids to peptides. The conversion was verified by matching the paper chromatogram of the experimental product with that of a known peptide. The experimental results demonstrate that the optimum solvent system for paper chromatographic analysis of the zeolite-catalyzed self-assembly of the amino acids L-aspartic acid, L- asparagine, L-histidine, and L-serine is a 50:50 mixture of 1-butanol and acetone by volume. For the amino acids L-alanine, L-glycine, and L-valine, the optimum solvent was found to be a 30:70 mixture of ammonia and propanol by volume. A mathematical model describing the distance traveled (spot position) versus reaction time was constructed for the zeolite-catalyzed conversion of L- leucine and L-tyrosine and was found to approximately follow the function f(t) = 25 ln t. Two case studies for prebiotic synthesis leading to the production of amino acids or peptides in extraterrestrial environments were discussed: one involving Saturn's moon Titan, and the other involving Jupiter's moon Europa. In the Titan study, it was determined

  5. Reducing Extra-Terrestrial Excavation Forces with Percussion

    Science.gov (United States)

    Schuler, Jason; Mueller, Robert; Smith, Drew; Nick, Andrew; Lippitt, Thomas

    2012-01-01

    reduction of as much as 72%. This paper will examine the effects of impact energy, frequency, scaling and their effect on excavation forces in a dry granular material such as lunar regolith. The past several years have shown an increasing interest in mining space resources both for exploration and commercial enterprises. This work studied the benefits and risks of percussive excavation and preliminry results indicate that this technique may become an enabling technology for extra-terrestrial excavation of regolith and ice.

  6. The forthcoming EISCAT_3D as an extra-terrestrial matter monitor

    Science.gov (United States)

    Pellinen-Wannberg, Asta; Kero, Johan; Häggström, Ingemar; Mann, Ingrid; Tjulin, Anders

    2016-04-01

    It is important to monitor the extra-terrestrial dust flux in the Earth's environment and into the atmosphere. Meteoroids threaten the infrastructure in space as hypervelocity hits by micron-sized granules continuously degrade the solar panels and other satellite surfaces. Through their orbital elements meteoroids can be associated to the interplanetary dust cloud, comets, asteroids or the interstellar space. The ablation products of meteoroids participate in many physical and chemical processes at different layers in the atmosphere, many of them occurring in the polar regions. High-power large-aperture (HPLA) radars, such as the tristatic EISCAT UHF together with the EISCAT VHF, have been versatile instruments for studying many properties of the meteoroid population, even though they were not initially designed for this purpose. The future EISCAT_3D will comprise a phased-array transmitter and several phased-array receivers distributed in northern Scandinavia. These will work at 233 MHz centre frequency with power up to 10 MW and run advanced signal processing systems. The facility will in many aspects be superior to its predecessors as the first radar to combine volumetric-, aperture synthesis- and multistatic imaging as well as adaptive experiments. The technical design goals of the radar respond to the scientific requests from the user community. The VHF frequency and the volumetric imaging capacity will increase the collecting volume compared to the earlier UHF, the high transmitter power will increase the sensitivity of the radar, and the interferometry will improve the spatial resolution of the orbit estimates. The facility will be able to observe and define orbits to about 10% of the meteors from the established mass flux distribution that are large or fast enough to produce an ionization mantle around the impacting meteoroid within the collecting volume. The estimated annual mean of about 190 000 orbits per day with EISCAT_3D gives many orders of magnitude

  7. The search for extraterrestrial intelligence: Listening for life in the cosmos

    Science.gov (United States)

    McDonough, Thomas R.

    The reasons for and the activities of SETI (Search for Extraterrestrial Intelligence) are discussed. The history of the notion of intelligent life existing on other worlds is reviewed, and ideas of aliens in modern popular culture are examined. Arguments for and against the existence of intelligent life elsewhere are considered. Reports of extraterrestrial intelligence that turned out to be false are described, as are the messages sent out from earth to any aliens that may find them. The fight to maintain SETI funding and the related efforts in other countries are discussed. The arguments about UFOs are reviewed.

  8. Shifted Excitation Raman Difference Spectroscopy applied to extraterrestrial particles returned from the asteroid Itokawa

    Science.gov (United States)

    Böttger, U.; Maiwald, M.; Hanke, F.; Braune, M.; Pavlov, S. G.; Schröder, S.; Weber, I.; Busemann, H.; Sumpf, B.; Tränkle, G.; Hübers, H.-W.

    2017-09-01

    Two extraterrestrial particles from the asteroid Itokawa are investigated applying Shifted Excitation Raman Difference Spectroscopy (SERDS). These particles were returned by the Hayabusa mission of the Japanese Space Agency JAXA. For SERDS a diode laser based microsystem light source at 488 nm is used for excitation. It has been found that fluorescence signals masking the Raman spectral features of interest can be substantially separated by applying SERDS. Therefore, SERDS improves the information obtained from the Raman spectra and enables a reliable analysis for investigations on extraterrestrial samples.

  9. PHYSICS

    CERN Multimedia

    Joe Incandela

    There have been two plenary physics meetings since the December CMS week. The year started with two workshops, one on the measurements of the Standard Model necessary for “discovery physics” as well as one on the Physics Analysis Toolkit (PAT). Meanwhile the tail of the “2007 analyses” is going through the last steps of approval. It is expected that by the end of January all analyses will have converted to using the data from CSA07 – which include the effects of miscalibration and misalignment. January Physics Days The first Physics Days of 2008 took place on January 22-24. The first two days were devoted to comprehensive re¬ports from the Detector Performance Groups (DPG) and Physics Objects Groups (POG) on their planning and readiness for early data-taking followed by approvals of several recent studies. Highlights of POG presentations are included below while the activities of the DPGs are covered elsewhere in this bulletin. January 24th was devo...

  10. PHYSICS

    CERN Multimedia

    J. Incandela

    The all-plenary format of the CMS week in Cyprus gave the opportunity to the conveners of the physics groups to present the plans of each physics analysis group for tackling early physics analyses. The presentations were complete, so all are encouraged to browse through them on the Web. There is a wealth of information on what is going on, by whom and on what basis and priority. The CMS week was followed by two CMS “physics events”, the ICHEP08 days and the physics days in July. These were two weeks dedicated to either the approval of all the results that would be presented at ICHEP08, or to the review of all the other Monte-Carlo based analyses that were carried out in the context of our preparations for analysis with the early LHC data (the so-called “2008 analyses”). All this was planned in the context of the beginning of a ramp down of these Monte Carlo efforts, in anticipation of data.  The ICHEP days are described below (agenda and talks at: http://indic...

  11. Physics

    CERN Document Server

    Cullen, Katherine

    2005-01-01

    Defined as the scientific study of matter and energy, physics explains how all matter behaves. Separated into modern and classical physics, the study attracts both experimental and theoretical physicists. From the discovery of the process of nuclear fission to an explanation of the nature of light, from the theory of special relativity to advancements made in particle physics, this volume profiles 10 pioneers who overcame tremendous odds to make significant breakthroughs in this heavily studied branch of science. Each chapter contains relevant information on the scientist''s childhood, research, discoveries, and lasting contributions to the field and concludes with a chronology and a list of print and Internet references specific to that individual.

  12. Value-at-risk estimations of energy commodities via long-memory, asymmetry and fat-tailed GARCH models

    Energy Technology Data Exchange (ETDEWEB)

    Aloui, Chaker; Mabrouk, Samir [International Finance-Group Tunisia, Faculty of Management and Economic Sciences of Tunis El Manar University. Boulevard du 7 novembre, El Manar, B.P. 248, C.P. 2092, Tunis Cedex (Tunisia)

    2010-05-15

    In this paper, we evaluate the value-at-risk (VaR) and the expected shortfalls for some major crude oil and gas commodities for both short and long trading positions. Classical VaR estimations as well as RiskMetrics and other extensions to cases considering for long-range memory, asymmetry and fat-tail in energy markets volatility were conducted. We computed the VaR for three ARCH/GARCH-type models including FIGARCH, FIAPARCH and HYGARCH. These models were estimated in the presence of three alternative innovation's distributions: normal, Student and skewed Student. Our results show that considering for long-range memory, fat-tails and asymmetry performs better in predicting a one-day-ahead VaR for both short and long trading positions. Moreover, the FIAPARCH model outperforms the other models in the VaR's prediction. These results present several potential implications for energy markets risk quantifications and hedging strategies. (author)

  13. PHYSICS

    CERN Multimedia

    Guenther Dissertori

    The time period between the last CMS week and this June was one of intense activity with numerous get-together targeted at addressing specific issues on the road to data-taking. The two series of workshops, namely the “En route to discoveries” series and the “Vertical Integration” meetings continued.   The first meeting of the “En route to discoveries” sequence (end 2007) had covered the measurements of the Standard Model signals as necessary prerequisite to any claim of signals beyond the Standard Model. The second meeting took place during the Feb CMS week and concentrated on the commissioning of the Physics Objects, whereas the third occurred during the April Physics Week – and this time the theme was the strategy for key new physics signatures. Both of these workshops are summarized below. The vertical integration meetings also continued, with two DPG-physics get-togethers on jets and missing ET and on electrons and photons. ...

  14. PHYSICS

    CERN Multimedia

    Chris Hill

    2012-01-01

    The months that have passed since the last CMS Bulletin have been a very busy and exciting time for CMS physics. We have gone from observing the very first 8TeV collisions produced by the LHC to collecting a dataset of the collisions that already exceeds that recorded in all of 2011. All in just a few months! Meanwhile, the analysis of the 2011 dataset and publication of the subsequent results has continued. These results come from all the PAGs in CMS, including searches for the Higgs boson and other new phenomena, that have set the most stringent limits on an ever increasing number of models of physics beyond the Standard Model including dark matter, Supersymmetry, and TeV-scale gravity scenarios, top-quark physics where CMS has overtaken the Tevatron in the precision of some measurements, and bottom-quark physics where CMS made its first discovery of a new particle, the Ξ*0b baryon (candidate event pictured below). Image 2:  A Ξ*0b candidate event At the same time POGs and PAGs...

  15. PHYSICS

    CERN Multimedia

    D. Acosta

    2011-01-01

    Since the last CMS Week, all physics groups have been extremely active on analyses based on the full 2010 dataset, with most aiming for a preliminary measurement in time for the winter conferences. Nearly 50 analyses were approved in a “marathon” of approval meetings during the first two weeks of March, and the total number of approved analyses reached 90. The diversity of topics is very broad, including precision QCD, Top, and electroweak measurements, the first observation of single Top production at the LHC, the first limits on Higgs production at the LHC including the di-tau final state, and comprehensive searches for new physics in a wide range of topologies (so far all with null results unfortunately). Most of the results are based on the full 2010 pp data sample, which corresponds to 36 pb-1 at √s = 7 TeV. This report can only give a few of the highlights of a very rich physics program, which is listed below by physics group...

  16. Multiplication of microbes below 0.690 water activity : implications for terrestrial and extraterrestrial life

    NARCIS (Netherlands)

    Stevenson, Andrew; Burkhardt, Jürgen; Cockell, Charles S; Cray, Jonathan A; Dijksterhuis, Jan; Fox-Powell, Mark; Kee, Terence P; Kminek, Gerhard; McGenity, Terry J; Timmis, Kenneth N; Timson, David J; Voytek, Mary A; Westall, Frances; Yakimov, Michail M; Hallsworth, John E

    2015-01-01

    Since a key requirement of known life forms is available water (water activity; aw ), recent searches for signatures of past life in terrestrial and extraterrestrial environments have targeted places known to have contained significant quantities of biologically available water. However, early life

  17. Abundances of lanthanoids, Th and U in extraterrestrial matters and their cosmochemical implications

    Energy Technology Data Exchange (ETDEWEB)

    Ebihara, M. [Tokyo Metropolitan Univ., Tokyo (Japan)

    2002-03-01

    Lanthanoid and actinoid abundances in the extraterrestrial materials are highly informative in discussing differentiation of planetary materials and cosmochronology at the early solar system. After briefly explaining analytical methods applicable to their determination, three research themes, two of which have been already in progress, are introduced and the significance of lanthanoids and actinoids in cosmochemical materials is emphasized. (author)

  18. SPE (tm) regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications

    Science.gov (United States)

    Mcelroy, J. F.

    1990-01-01

    Viewgraphs on SPE regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications are presented. Topics covered include: hydrogen-oxygen regenerative fuel cell energy storage system; electrochemical cell reactions; SPE cell voltage stability; passive water removal SPE fuel cell; fuel cell performance; SPE water electrolyzers; hydrophobic oxygen phase separator; hydrophilic/electrochemical hydrogen phase separator; and unitized regenerative fuel cell.

  19. Search for extraterrestrial antineutrino sources with the KamLAND detector

    NARCIS (Netherlands)

    Abe, S.; et al., [Unknown; Decowski, M.P.

    2012-01-01

    We present the results of a search for extraterrestrial electron antineutrinos ( 's) in the energy range 8.3 MeV < Eve < 31.8 MeV using the KamLAND detector. In an exposure of 4.53 kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most important

  20. PHYSICS

    CERN Multimedia

    the PAG conveners

    2011-01-01

    The delivered LHC integrated luminosity of more than 1 inverse femtobarn by summer and more than 5 by the end of 2011 has been a gold mine for the physics groups. With 2011 data, we have submitted or published 14 papers, 7 others are in collaboration-wide review, and 75 Physics Analysis Summaries have been approved already. They add to the 73 papers already published based on the 2010 and 2009 datasets. Highlights from each physics analysis group are described below. Heavy ions Many important results have been obtained from the first lead-ion collision run in 2010. The published measurements include the first ever indications of Υ excited state suppression (PRL synopsis), long-range correlation in PbPb, and track multiplicity over a wide η range. Preliminary results include the first ever measurement of isolated photons (showing no modification), J/ψ suppression including the separation of the non-prompt component, further study of jet fragmentation, nuclear modification factor...

  1. PHYSICS

    CERN Multimedia

    C. Hill

    2012-01-01

      The period since the last CMS Bulletin has been historic for CMS Physics. The pinnacle of our physics programme was an observation of a new particle – a strong candidate for a Higgs boson – which has captured worldwide interest and made a profound impact on the very field of particle physics. At the time of the discovery announcement on 4 July, 2012, prominent signals were observed in the high-resolution H→γγ and H→ZZ(4l) modes. Corroborating excess was observed in the H→W+W– mode as well. The fermionic channel analyses (H→bb, H→ττ), however, yielded less than the Standard Model (SM) expectation. Collectively, the five channels established the signal with a significance of five standard deviations. With the exception of the diphoton channel, these analyses have all been updated in the last months and several new channels have been added. With improved analyses and more than twice the i...

  2. PHYSICS

    CERN Multimedia

    D. Acosta

    2010-01-01

    The Physics Groups are actively engaged on analyses of the first data from the LHC at 7 TeV, targeting many results for the ICHEP conference taking place in Paris this summer. The first large batch of physics approvals is scheduled for this CMS Week, to be followed by four more weeks of approvals and analysis updates leading to the start of the conference in July. Several high priority analysis areas were organized into task forces to ensure sufficient coverage from the relevant detector, object, and analysis groups in the preparation of these analyses. Already some results on charged particle correlations and multiplicities in 7 TeV minimum bias collisions have been approved. Only one small detail remains before ICHEP: further integrated luminosity delivered by the LHC! Beyond the Standard Model measurements that can be done with these data, the focus changes to the search for new physics at the TeV scale and for the Higgs boson in the period after ICHEP. Particle Flow The PFT group is focusing on the ...

  3. PHYSICS

    CERN Multimedia

    C. Hill

    2012-01-01

      2012 has started off as a very busy year for the CMS Physics Groups. Planning for the upcoming higher luminosity/higher energy (8 TeV) operation of the LHC and relatively early Rencontres de Moriond are the high-priority activities for the group at the moment. To be ready for the coming 8-TeV data, CMS has made a concerted effort to perform and publish analyses on the 5 fb−1 dataset recorded in 2011. This has resulted in the submission of 16 papers already, including nine on the search for the Higgs boson. In addition, a number of preliminary results on the 2011 dataset have been released to the public. The Exotica and SUSY groups approved several searches for new physics in January, such as searches for W′ and exotic highly ionising particles. These were highlighted at a CERN seminar given on 24th  January. Many more analyses, from all the PAGs, including the newly formed SMP (Standard Model Physics) and FSQ (Forward and Small-x QCD), were approved in February. The ...

  4. PHYSICS

    CERN Multimedia

    Darin Acosta

    2010-01-01

    The collisions last year at 900 GeV and 2.36 TeV provided the long anticipated collider data to the CMS physics groups. Quite a lot has been accomplished in a very short time. Although the delivered luminosity was small, CMS was able to publish its first physics paper (with several more in preparation), and commence the commissioning of physics objects for future analyses. Many new performance results have been approved in advance of this CMS Week. One remarkable outcome has been the amazing agreement between out-of-the-box data with simulation at these low energies so early in the commissioning of the experiment. All of this is testament to the hard work and preparation conducted beforehand by many people in CMS. These analyses could not have happened without the dedicated work of the full collaboration on building and commissioning the detector, computing, and software systems combined with the tireless work of many to collect, calibrate and understand the data and our detector. To facilitate the efficien...

  5. PHYSICS

    CERN Multimedia

    L. Demortier

    Physics-wise, the CMS week in December was dominated by discussions of the analyses that will be carried out in the “next six months”, i.e. while waiting for the first LHC collisions.  As presented in December, analysis approvals based on Monte Carlo simulation were re-opened, with the caveat that for this work to be helpful to the goals of CMS, it should be carried out using the new software (CMSSW_2_X) and associated samples.  By the end of the week, the goal for the physics groups was set to be the porting of our physics commissioning methods and plans, as well as the early analyses (based an integrated luminosity in the range 10-100pb-1) into this new software. Since December, the large data samples from CMSSW_2_1 were completed. A big effort by the production group gave a significant number of events over the end-of-year break – but also gave out the first samples with the fast simulation. Meanwhile, as mentioned in December, the arrival of 2_2 meant that ...

  6. EmPirical Study on Investment Risk of Gold and Oil Based on GARCH-VaR Model%基于GARCH-VaR模型的黄金和石油投资风险实证研究

    Institute of Scientific and Technical Information of China (English)

    钱凯; 伍笑萍

    2014-01-01

    We made simPle descriPtive statistics on gold an d oil Price firstly and did emPirical analy-sis on the value of risk returns of gold and oil with GARCH model and Parameter VaR method,then tested the results. It shows that the investment risk of oil is bigger than gold,and oil risk volatility is also larger in a certain time interval,but the average yield of oil is higher than gold. It is clear that high income always accomPanies with high risk. At the same time we Put forward some relevant sug-gestions on the Problems,so as to Provide reference information for investors in making investment de-cisions.%首先对黄金和石油序列进行了简单的描述性统计,然后运用GARCH模型和参数VaR法对黄金和石油收益率的风险价值进行实证分析,并对结果进行检验。结果表明:石油比黄金的投资风险要大,而且在一定时间区间内,石油的风险价值波动幅度也较大,但石油的平均收益率高于黄金。可见,高收益伴随着高风险。同时,对出现的问题提出相关建议,为机构投资者在进行投资决策时提供参考信息。

  7. 基于 ARMA -GARCH 的股指期货实证分析%An Empirical Research of Stock Index Futures in China Based on ARMA-GARCH Model

    Institute of Scientific and Technical Information of China (English)

    李丹; 郑伟; 张伟伟; 徐天群

    2014-01-01

    Based on the series data of 300 stock indexes in Shanghai and Shenzhen Stock Market , the stability of the return series was studied;and ARMA-GARCH model for the return series was established .According to the mean equation and vola-tility equation in the model , it was found that the initial futures trading tend to be risk adverse players , and the business cycle of income was about 3.6 days, and the stock index futures market volatility presented ARCH effect and the characteristics of long memory.It showed that the feedback of information of the market is very sensitive and rapid at beginning and the group effect and chain behavior would increase market risks .%基于沪深300股票指数期货的时间序列数据,研究了股指期货收益序列的平稳性,建立了ARMA-GARCH模型,通过模型中的均值方程和波动方程,发现初期期货市场上的交易状况偏向于风险厌恶型,得到了收益变化的循环周期大约为3.6天,股指期货市场的波动存在ARCH效应和长记忆性特点。说明市场初期交易者对市场的信息反馈非常敏感和迅速,并且呈现出群体效应和连锁行为,有增大市场风险的可能。

  8. PHYSICS

    CERN Multimedia

    J. D'Hondt

    The Electroweak and Top Quark Workshop (16-17th of July) A Workshop on Electroweak and Top Quark Physics, dedicated on early measurements, took place on 16th-17th July. We had more than 40 presentations at the Workshop, which was an important milestone for 2007 physics analyses in the EWK and TOP areas. The Standard Model has been tested empirically by many previous experiments. Observables which are nowadays known with high precision will play a major role for data-based CMS calibrations. A typical example is the use of the Z to monitor electron and muon reconstruction in di-lepton inclusive samples. Another example is the use of the W mass as a constraint for di-jets in the kinematic fitting of top-quark events, providing information on the jet energy scale. The predictions of the Standard Model, for what concerns proton collisions at the LHC, are accurate to a level that the production of W/Z and top-quark events can be used as a powerful tool to commission our experiment. On the other hand the measure...

  9. PHYSICS

    CERN Multimedia

    C. Hill

    2013-01-01

    In the period since the last CMS Bulletin, the LHC – and CMS – have entered LS1. During this time, CMS Physics Analysis Groups have performed more than 40 new analyses, many of which are based on the complete 8 TeV dataset delivered by the LHC in 2012 (and in some cases on the full Run 1 dataset). These results were shown at, and well received by, several high-profile conferences in the spring of 2013, including the inaugural meeting of the Large Hadron Collider    Physics Conference (LHCP) in Barcelona, and the 26th International Symposium on Lepton Photon Interactions at High Energies (LP) in San Francisco. In parallel, there have been significant developments in preparations for Run 2 of the LHC and on “future physics” studies for both Phase 1 and Phase 2 upgrades of the CMS detector. The Higgs analysis group produced five new results for LHCP including a new H-to-bb search in VBF production (HIG-13-011), ttH with H to γ&ga...

  10. PHYSICS

    CERN Multimedia

    C. Hill

    2013-01-01

    The period since the last CMS bulletin has seen the end of proton collisions at a centre-of-mass energy 8 TeV, a successful proton-lead collision run at 5 TeV/nucleon, as well as a “reference” proton run at 2.76 TeV. With these final LHC Run 1 datasets in hand, CMS Physics Analysis Groups have been busy analysing these data in preparation for the winter conferences. Moreover, despite the fact that the pp run only concluded in mid-December (and there was consequently less time to complete data analyses), CMS again made a strong showing at the Rencontres de Moriond in La Thuile (EW and QCD) where nearly 40 new results were presented. The highlight of these preliminary results was the eagerly anticipated updated studies of the properties of the Higgs boson discovered in July of last year. Meanwhile, preparations for Run 2 and physics performance studies for Phase 1 and Phase 2 upgrade scenarios are ongoing. The Higgs analysis group produced updated analyses on the full Run 1 dataset (~25 f...

  11. PHYSICS

    CERN Multimedia

    Christopher Hill

    2013-01-01

    Since the last CMS Bulletin, the CMS Physics Analysis Groups have completed more than 70 new analyses, many of which are based on the complete Run 1 dataset. In parallel the Snowmass whitepaper on projected discovery potential of CMS for HL-LHC has been completed, while the ECFA HL-LHC future physics studies has been summarised in a report and nine published benchmark analyses. Run 1 summary studies on b-tag and jet identification, quark-gluon discrimination and boosted topologies have been documented in BTV-13-001 and JME-13-002/005/006, respectively. The new tracking alignment and performance papers are being prepared for submission as well. The Higgs analysis group produced several new results including the search for ttH with H decaying to ZZ, WW, ττ+bb (HIG-13-019/020) where an excess of ~2.5σ is observed in the like-sign di-muon channel, and new searches for high-mass Higgs bosons (HIG-13-022). Search for invisible Higgs decays have also been performed both using the associ...

  12. 基于GJR-GARCH-DCC模型的沪深港股市的联动性研究

    Institute of Scientific and Technical Information of China (English)

    姚琼

    2012-01-01

    以沪深港三地股票市场指数数据为样本,通过构建三元GJR-GARCH-DCC模型对沪深港股市之间的联动效应进行了分析。首先选择向量自回归(VAR)模型作为条件均值方程的形式,并在此基础上进行了格兰杰因果关系检验和脉冲响应分析,然后考察了条件方差方程和DCC方程,最后刻画出沪深港股市的动态相关系数图。分析结果表明,沪深港股市之间存在明显的联动性,股权分置改革之后,中国内地股市更加国际化,市场之间的关系存在非对称性,沪市在三个市场之间已经起到了主导作用,市场间的动态相关性呈现增加的趋势。投资者可以利用股市联动性的增强对股市的走势进行预测,同时监管部门也应该完善股市的制度,建立危机预警机制,以防止由联动性导致的国内外股市风险。

  13. 基于Copula-GARCH-EVT的开放式基金投资组合风险度量探析

    Institute of Scientific and Technical Information of China (English)

    吴智麟; 刘照龙

    2010-01-01

    结合GARCH模型和EVT理论刻画了单个金融资产收益率的波动性和尾部分布,并将Copula函数和Monte Carlo技术应用于证券投资组合的VaR计算方法,通过对广发聚丰基金的实证研究,得到前十大重仓股票投资组合的风险价值,结果表明基于Copula-GARCH-EVT的VaR方法具有重要的应用价值.

  14. Fama-French-ARMA-GJR-GARCH-AEPD定价模型——基于次贷危机影响下美股收益率的实证研究

    Institute of Scientific and Technical Information of China (English)

    郭小稚; 张晓峒

    2015-01-01

    在Fama-French四因子定价模型的基础上,运用Fama-French-ARMAGJR-GARCH-AEPD模型进行实证分析,结果表明此模型不仅能更好地拟合次贷危机影响下下跌的美股与复苏美股的收益率、消除自相关与ARCH效应问题,而且AEPD分布既能捕捉到残差的偏度又能获得残差的左尾和右尾分布情况。以"日"为单位,用固定长度的滚动时间窗口的预测方法,Fama-French-ARMA-GJR-GARCH-AEPD模型的预测值要好于Fama-French-ARMA-GJR-GARCH-Normal模型的预测值。

  15. Transmission of prices and price volatility in Australian electricity spot markets: a multivariate GARCH analysis

    Energy Technology Data Exchange (ETDEWEB)

    Worthington, A.; Kay-Spratley, A.; Higgs, H. [Queensland University of Technology, Brisbane (Australia). School of Economics and Finance

    2005-03-01

    This paper examines the transmission of spot electricity prices and price volatility among the five regional electricity markets in the Australian National Electricity Market: namely, New South Wales, Queensland, South Australia, the Snowy Mountains Hydroelectric Scheme and Victoria. A multivariate generalised autoregressive conditional heteroskedasticity model is used to identify the source and magnitude of price and price volatility spillovers. The results indicate the presence of positive own mean spillovers in only a small number of markets and no mean spillovers between any of the markets. This appears to be directly related to the physical transfer limitations of the present system of regional interconnection. Nevertheless, the large number of significant own-volatility and cross-volatility spillovers in all five markets indicates the presence of strong autoregressive conditional heteroskedasticity and generalised autoregressive conditional heteroskedasticity effects. This indicates that shocks in some markets will affect price volatility in others. Finally, and contrary to evidence from studies in North American electricity markets, the results also indicate that Australian electricity spot prices are stationary. (author)

  16. Transmission of prices and price volatility in Australian electricity spot markets. A multivariate GARCH analysis

    Energy Technology Data Exchange (ETDEWEB)

    Worthington, Andrew; Kay-Spratley, Adam; Higgs, Helen [School of Economics and Finance, Queensland University of Technology, G.P.O. Box 2434, Brisbane, Qld 4001 (Australia)

    2005-03-15

    This paper examines the transmission of spot electricity prices and price volatility among the five regional electricity markets in the Australian National Electricity Market: namely, New South Wales, Queensland, South Australia, the Snowy Mountains Hydroelectric Scheme and Victoria. A multivariate generalised autoregressive conditional heteroskedasticity model is used to identify the source and magnitude of price and price volatility spillovers. The results indicate the presence of positive own mean spillovers in only a small number of markets and no mean spillovers between any of the markets. This appears to be directly related to the physical transfer limitations of the present system of regional interconnection. Nevertheless, the large number of significant own-volatility and cross-volatility spillovers in all five markets indicates the presence of strong autoregressive conditional heteroskedasticity and generalised autoregressive conditional heteroskedasticity effects. This indicates that shocks in some markets will affect price volatility in others. Finally, and contrary to evidence from studies in North American electricity markets, the results also indicate that Australian electricity spot prices are stationary.

  17. PHYSICS

    CERN Multimedia

    V.Ciulli

    2011-01-01

    The main programme of the Physics Week held between 16th and 20th May was a series of topology-oriented workshops on di-leptons, di-photons, inclusive W, and all-hadronic final states. The goal of these workshops was to reach a common understanding for the set of objects (ID, cleaning...), the handling of pile-up, calibration, efficiency and purity determination, as well as to revisit critical common issues such as the trigger. Di-lepton workshop Most analysis groups use a di-lepton trigger or a combination of single and di-lepton triggers in 2011. Some groups need to collect leptons with as low PT as possible with strong isolation and identification requirements as for Higgs into WW at low mass, others with intermediate PT values as in Drell-Yan studies, or high PT as in the Exotica group. Electron and muon reconstruction, identification and isolation, was extensively described in the workshop. For electrons, VBTF selection cuts for low PT and HEEP cuts for high PT were discussed, as well as more complex d...

  18. Ion exchange substrates for plant cultivation in extraterrestrial stations and space crafts

    Science.gov (United States)

    Soldatov, Vladimir

    2012-07-01

    Ion exchange substrates Biona were specially designed at the Belarus Academy of Sciences for plants cultivation in spacecrafts and extraterrestrial stations. The first versions of such substrates have been successfully used in several space experiments and in a long-term experiment in which three soviet test-spacemen spent a full year in hermetic cabin imitating a lunar station cabin (1067-1968). In this experiment the life support system included a section with about one ton of the ion exchange substrate, which was used to grow ten vegetations of different green cultures used in the food of the test persons. Due to failure of a number of Soviet space experiments, decay of the Soviet Union and the following economic crisis the research in this field carried out in Belarus were re-directed to the needs of usual agriculture, such as adaptation of cell cultures, growing seedlings, rootage of cuttings etc. At present ion exchange substrate Biona are produced in limited amounts at the experimental production plant of the Institute of Physical Organic Chemistry and used in a number of agricultural enterprises. New advanced substrates and technologies for their production have been developed during that time. In the presentation scientific principles of preparation and functioning of ion exchange substrates as well as results of their application for cultivation different plants are described. The ion exchange substrate is a mixture of cation and anion exchangers saturated in a certain proportions with all ions of macro and micro elements. These chemically bound ions are not released to water and become available for plants in exchange to their root metabolites. The substrates contain about 5% mass of nutrient elements far exceeding any other nutrient media for plants. They allow generating 3-5 kg of green biomass per kilogram of substrate without adding any fertilizers; they are sterile by the way of production and can be sterilized by usual methods; allow regeneration

  19. Beyond the Drake Equation: On the Probability of the Nature of Extraterrestrial Life Forms in Our Galaxy Today

    Science.gov (United States)

    Geller, Harold A.

    2014-01-01

    I will discuss my research into the issues associated with the nature of any extraterrestrials that may be encountered in the future in our galaxy. This research was sparked by statements made by Stephen Hawking in 2010 regarding his fear of emitting radiation from our Earth so that an extraterrestrial intelligent civilization may be alerted to our existence in the galaxy today. While addressing issues of extraterrestrial altruism, a probabilistic equation was developed which addresses the number of extraterrestrial intelligent life forms that may exist in our galaxy today, who could use our bodies for nourishment or reproductive purposes. The equation begins with the results from a Drake Equation calculation, and proceeds by addressing such biochemical parameters as the fraction of ETIs with: dextro sugar stereo-isomers; levo amino acid stereo-isomers; similar codon interpretation; chromosomal length and, similar cell membrane structure to allow egg penetration.

  20. 基于 ARMA-GARCH 模型的恒指隐含波动率指数预测及其在期权交易中的应用%Forecasting Hang Seng Implied Volatility Index Based on ARMA-GARCH Model and Its Application in Option Trading

    Institute of Scientific and Technical Information of China (English)

    陈彦晖

    2014-01-01

    This paper investigated whether the implied volatility index can be predicted with mean-reversion,spillover effect and day-of-week effect by using ARMA-GARCH model.The results show that Hong Kong Stock market is mean-rever-sion and S&P 500 index shows significant spillover effect to VHSI.Refer to the day-of-week effect,Hang Seng implied volatil-ity Index (VHSI)tends to rise on Mondays and decline on Fridays.Finally,this research explores whether the prediction of implied volatility can provide additional value to practitioners and retail investors alike.The result suggests that option trading based on volatility prediction is practical for option traders.%基于 ARMA-GARCH 模型,并结合均值回归效应,溢出效应和周内效应,本文研究了恒指隐含波动率指数(VHSI)能否被预测及预测是否有助于期权投资实践的问题。研究结果验证了香港股市具有均值回归的特性,标准普尔500指数对恒指隐含波动率指数有明显的溢出效应。此外,恒指隐含波动率指数呈现出周一上涨,周五下跌的特征,具有明显的周内效应。最后,本文运用 ARMA-GARCH 模型对恒指隐含波动率指数进行预测,并结合实际的市场数据做了期权交易模拟。结果显示,ARMA-GARCH 模型比ARMA 模型更适合对恒指隐含波动率进行建模;考虑了均值回归效应,溢出效应和周内效应之后,ARMA-GARCH 模型对恒指隐含波动率指数的预测能力显著提高,并且预测结果有助于期权交易获得较好的收益。

  1. Alien Mindscapes—A Perspective on the Search for Extraterrestrial Intelligence

    Science.gov (United States)

    Cabrol, Nathalie A.

    2016-09-01

    Advances in planetary and space sciences, astrobiology, and life and cognitive sciences, combined with developments in communication theory, bioneural computing, machine learning, and big data analysis, create new opportunities to explore the probabilistic nature of alien life. Brought together in a multidisciplinary approach, they have the potential to support an integrated and expanded Search for Extraterrestrial Intelligence (SETI1), a search that includes looking for life as we do not know it. This approach will augment the odds of detecting a signal by broadening our understanding of the evolutionary and systemic components in the search for extraterrestrial intelligence (ETI), provide more targets for radio and optical SETI, and identify new ways of decoding and coding messages using universal markers.

  2. Search For Evidence Of Extraterrestrial Life: Societal Issues And Concerns A Panel Discussion

    Science.gov (United States)

    Race, M.; Schwehm, G.; Horneck, G.

    2003-04-01

    The search for evidence of extraterrestrial life is an important scientific theme that fascinates the public and encourages interest in space exploration, both within the solar system and beyond. The rapid pace of mass media communication allows the public to share mission results and new discoveries almost simultaneously with the scientific community. As the science community continues its multi-pronged efforts to detect evidence of extraterrestrial life, it must be mindful of more than just science and technology. It is important to understand public perceptions, misperceptions, beliefs, concerns, and potential legal complications associated with the search for life beyond our home planet. This session with invited panelists is designed to provide brief overviews of some important non-scientific areas with the potential to impact future missions and astrobiological exploration. The brief presentations will be followed by open discussion and audience participation.

  3. First search for extraterrestrial neutrino-induced cascades with IceCube

    CERN Document Server

    Kiryluk, J

    2009-01-01

    We report on the first search for extra-terrestrial neutrino-induced cascades in IceCube. The analyzed data were collected in the year 2007 when 22 detector strings were installed and operated. We will discuss the analysis methods used to reconstruct cascades and to suppress backgrounds. Simulated neutrino signal events with a E-2 energy spectrum, which pass the background rejection criteria, are reconstructed with a resolution dlogE ~ 0.27 in the energy range from ~20 TeV to a few PeV. We present the range of the diffuse flux of extra-terrestrial neutrinos in the cascade channel in IceCube within which we expect to be able to put a limit.

  4. Limits on diffuse fluxes of high energy extraterrestrial neutrinos with the AMANDA-B10 detector

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, J.; Bai, X.; Barwick, S.W.; Bay, R.C.; Becka, T.; Becker, K.-H.; Bernardini, E.; Bertrand, D.; Binon, F.; Boeser, S.; Botner, O.; Bouchta, A.; Bouhali, O.; Burgess, T.; Carius, S.; Castermans, T.; Chirkin, D.; Conrad, J.; Cooley, J.; Cowen, D.F.; Davour, A.; De Clercq, C.; DeYoung, T.; Desiati, P.; Doksus, P.; Ekstrom, P.; Feser, T.; Gaisser, T.K.; Ganugapati, R.; Gaug, M.; Geenen, H.; Gerhardt, L.; Goldschmidt, A.; Hallgren, A.; Halzen, F.; Hanson, K.; Hardtke, R.; Hauschildt, T.; Hellwig, M.; Herquet, P.; Hill, G.C.; Hulth, P.O.; Hughey, B.; Hultqvist, K.; Hundertmark, S.; Jacobsen, J.; Karle, A.; Kuehn, K.; Kim, J.; Kopke, L.; Kowalski, M.; Lamoureux, J.I.; Leich, H.; Leuthold, M.; Lindahl, P.; Liubarsky, I.; Madsen, J.; Mandli, K.; Marciniewski, P.; Matis, H.S.; McParland, C.P.; Messarius, T.; Miller, T.C.; Minaeva, Y.; Miocinovic, P.; Mock, P.C.; Morse, R.; Neunhoffer, T.; Niessen, P.; Nygren, D.R.; Ogelman, H.; Olbrechts, P.; Perez de los Heros, C.; Pohl, A.C.; Porrata, R.; Price, P.B.; Przybylski, G.T.; Rawlins, K.; Resconi, E.; Rhode, W.; Ribordy, M.; Richter, S.; Rodriguez Martino, J.; Romenesko, P.; Ross, D.; Sander, H.-G.; Schlenstedt, S.; Schinarakis, K.; Schmidt, T.; Schneider, D.; Schwarz, R.; Silvestri, A.; Solarz, M.; Stamatikos, M.; Spiczak, G.M.; Spiering, C.; Steele, D.; Steffen, P.; Stokstad, R.G.; Sulanke, K.-H.; Taboada, I.; Tilav, S.; Wagner, W.; Walck, C.; Wang, Y.-R.; Wiebusch, C.H.; Wiedemann, C.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Wu, W.; Yodh, G.; Young, S.

    2003-03-11

    Data from the AMANDA-B10 detector taken during the austral winter of 1997 have been searched for a diffuse flux of high energy extraterrestrial muon-neutrinos, as predicted from, e.g., the sum of all active galaxies in the universe. This search yielded no excess events above those expected from the background atmospheric neutrinos, leading to upper limits on the extraterrestrial neutrino flux. For an assumed E{sup -2} spectrum, a 90 percent classical confidence level upper limit has been placed at a level E{sup 2} Phi(E) = 8.4 x 10{sup -7} GeV cm{sup -2} s{sup -1}1 sr{sup -1} (for a predominant neutrino energy range 6-1000 TeV) which is the most restrictive bound placed by any neutrino detector. When specific predicted spectral forms are considered, it is found that some are excluded.

  5. First search for extraterrestrial neutrino-induced cascades with IceCube

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Kiryluk, Joanna

    2009-05-22

    We report on the first search for extraterrestrial neutrino-induced cascades in IceCube.The analyzed data were collected in the year 2007 when 22 detector strings were installed and operated. We will discuss the analysis methods used to reconstruct cascades and to suppress backgrounds. Simulated neutrino signal events with a E-2 energy spectrum, which pass the background rejection criteria, are reconstructed with a resolution Delta(log E) ~;; 0.27 in the energy range from ~;; 20 TeV to a few PeV. We present the range of the diffuse flux of extra-terrestrial neutrinos in the cascade channel in IceCube within which we expect to be able to put a limit.

  6. Basic elements of an international terrestrial reply following the detection of a signal from extraterrestrial intelligence

    Science.gov (United States)

    Reijnen, G. C. M.

    One of the most tantalizing questions human intelligence has posed itself since the beginnings of time is whether we are alone in the Universe. And if not, where are "the others," and is it possible that these "others" may contact us, with or without our knowledge? Scientific literature abounds with theories pro and con, and if any subject ever lent itself to make-believe it is this one. Connected with the scientific theories on the subject, which are so often misunderstood, popular belief has led to a steady stream of publications which have done nothing if they have not greatly hampered the real issue. In legal circles the subject of possible contacts with extraterrestrial intelligence was first discussed in the literature in the early 1960's when, among others, Andrew Haley wrote, in 1965, about "Space Law and Government." This publication appeared in the midst of the United Nations preparations for what was to become, in 1967, the Outer Space Treaty. Though the idea of an international protocol governing actions after the detection of a signal from extraterrestrial intelligence has never been on the agenda of the United Nations Committee on the Peaceful Uses of Outer Space, space lawyers continue to think and to write about that subject. Recent advances in spaceflight, in particular the Voyager missions to the outer planets of our solar system, give the subject a new impetus. The present paper is intended to dwell upon present scientific thoughts about the likelihood that a signal from extraterrestrial intelligence will be detected in the near future. Although this likelihood appears to be remote, it seems, nevertheless, worthwhile that discussion continues in space legal circles regarding the formulation of an international protocol for activities following the detection of a signal from extraterrestrial intelligence. Since the confirmed detection of a signal from extraterrestrial intelligence could well be of crucial importance for the continuing existence of

  7. The Use of Extraterrestrial Resources to Facilitate Space Science and Exploration

    CERN Document Server

    Crawford, Ian A; Carpenter, James

    2016-01-01

    To-date, all human economic activity has depended on the resources of a single planet, and it has long been recognized that developments in space exploration could in principle open our closed planetary economy to external resources of energy and raw materials. Recently, there has been renewed interest in these possibilities, with several private companies established with the stated aim of exploiting extraterrestrial resources. Space science and exploration are among the potential beneficiaries of space resources because their use may permit the construction and operation of scientific facilities in space that will be unaffordable if all the required material and energy resources have to be lifted out of Earth's gravity. Examples may include the next generation of large space telescopes, sample return missions to the outer Solar System, and human research stations on the Moon and Mars. These potential scientific benefits of extraterrestrial resource utilisation were the topic of a Royal Astronomical Society ...

  8. Finding extraterrestrial life using ground-based high-resolution spectroscopy

    CERN Document Server

    Snellen, Ignas; Poole, Rudolf Le; Brogi, Matteo; Birkby, Jayne

    2013-01-01

    Exoplanet observations promise one day to unveil the presence of extraterrestrial life. Atmospheric compounds in strong chemical disequilibrium would point to large-scale biological activity just as oxygen and methane do in the Earth's atmosphere. The cancellation of both the Terrestrial Planet Finder and Darwin missions means that it is unlikely that a dedicated space telescope to search for biomarker gases in exoplanet atmospheres will be launched within the next 25 years. Here we show that ground-based telescopes provide a strong alternative for finding biomarkers in exoplanet atmospheres through transit observations. Recent results on hot Jupiters show the enormous potential of high-dispersion spectroscopy to separate the extraterrestrial and telluric signals making use of the Doppler shift of the planet. The transmission signal of oxygen from an Earth-twin orbiting a small red dwarf star is only a factor 3 smaller than that of carbon monoxide recently detected in the hot Jupiter tau Bootis b, albeit such...

  9. Origin of spherule samples recovered from antarctic ice sheet-Terrestrial or extraterrestrial?

    Energy Technology Data Exchange (ETDEWEB)

    Sekimoto, Shun; Takamiya, Koichi; Shibata, Seiichi [Research Reactor Institute, Kyoto University, Osaka (Japan); Kobayashi, Takayuki [College of Humanities and Sciences, Nihon University, Tokyo (Japan); Ebihara, Mitsuru [Dept. of Chemistry, Tokyo Metropolitan University, Tokyo (Japan)

    2016-04-15

    Thirty-eight spherules from the Antarctic ice sheet were analyzed using neutron activation analysis under two different conditions to investigate their origin. In almost all of these spherules, the contents of iron, cobalt, and manganese were determined to be 31% to 88%, 17 mg/kg to 810 mg/kg, and 0.017% to 7%, respectively. A detectable iridium content of 0.84 mg/kg was found in only one spherule, which was judged to be extraterrestrial in origin. A comparison of elemental compositions of the Antarctic spherules analyzed in this study with those of deep-sea sediment spherules and those of terrestrial materials revealed that most of the Antarctic spherules except for the sample in which iridium was detected could not be identified as extraterrestrial in origin.

  10. Our Sky Now and Then: Searches for Lost Stars and Impossible Effects as Probes of Advanced Extraterrestrial Civilizations

    Science.gov (United States)

    Villarroel, Beatriz; Imaz, Inigo; Bergstedt, Josefine

    2016-09-01

    Searches for extraterrestrial intelligence using large survey data often look for possible signatures of astroengineering. We propose searching for physically impossible effects caused by highly advanced technology by carrying out a search for disappearing galaxies and Milky Way stars. We select ˜10 million objects from USNO-B1.0 with low proper motions (μ search for objects not found at the expected positions in the Sloan Digital Sky Survey (SDSS) by visually examining images of ˜290,000 USNO-B1.0 objects with no counterpart in the SDSS. We identify some spurious targets in the USNO-B1.0. We find one candidate of interest for follow-up photometry, although it is very uncertain. If the candidate eventually is found, it defines the probability of observing a disappearing-object event in the last decade to less than one in one million in the given samples. Nevertheless, because the complete USNO-B1.0 data set is 100 times larger than any of our samples, we propose an easily accessible citizen science project in search of USNO-B1.0 objects that have disappeared from the SDSS.

  11. Our Sky now and then $-$ searches for lost stars and impossible effects as probes of advanced extra-terrestrial civilisations

    CERN Document Server

    Villarroel, Beatriz; Bergstedt, Josefine

    2016-01-01

    Searches for extra-terrestrial intelligence (SETI) using large survey data often look for possible signatures of astroengineering. We propose to search for physically impossible effects caused by highly advanced technology, by carrying out a search for disappearing galaxies and Milky Way stars. We select $\\sim$ 10 million objects from USNO-B1.0 with low proper motion ($\\mu$ $<$ 20 milli arcseconds / year) imaged on the sky in two epochs. We search for objects not found at the expected positions in the Sloan Digital Sky Survey (SDSS) by visually examining images of $\\sim$ 290 000 USNO-B1.0 objects with no counterpart in the SDSS. We identify some spurious targets in the USNO-B1.0. We find one candidate of interest for follow-up photometry, although it is very uncertain. If the candidate eventually is found, it defines the probability of observing a disappearing-object event the last decade to less than one in one million in the given samples. Nevertheless, since the complete USNO-B1.0 dataset is 100 times l...

  12. The nations united in the scientific and political debate of the Search for Extraterrestrial Intelligence (SETI)

    Science.gov (United States)

    Reijnen, Bess

    Since 1959 (Cocconi and Morrison), the item of the search for extra-terrestrial intelligence (SETI) has continuously been debated in scientific fora. Since the 1970's (Fasan, 1970; Reijnen 1976), political and legal experts have regularly written on the subject while, in 1977, the UNCOPUOS published a review on SETI (UN Doc. A/AC. 105/206, of 18.10.77) entitled: 'Messages to extraterrestrial Civilizations'. In the mid-1980 s, international agreements as well as legal principles relating to contact and communication with ETI were proposed (Acta Astronautica, 1990). Though there is, as yet, no confirmed evidence of an extra-terrestrial contact with Earth ever having been established, the search continues. The international political and legal framework as well as the contents of a potential terrestrial reply also remains an issue of continuous discussions (Acta Astronautica, 1990). The time seems ripe for a concerted effort by humankind to address the societal and, principally, political decisions to be taken in international governmental bodies equipped to deal with the multitude of scientific and political questions and implications to be solved. The political/legal questions will be investigated, the main remaining issues addressed, and suggestions presented for implementation of the issue in intergovernmental and non-governmental bodies. 'SETI essentially is a philosophical venture and, perhaps, the most important man has ever contemplated'. (Coffey, 1980).

  13. Extraterrestrial Organic Chemistry: From the Interstellar Medium to the Origins of Life

    Science.gov (United States)

    Pohorille, Andrew; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Extraterrestrially delivered organics in the origin of cellular life. Various processes leading to the emergence of cellular life from organics delivered from space to earth or other planetary bodies in the solar system will be reviewed. The focus will be on: (1) self-assembly of amphiphilic material to vesicles and other structures, such as micelles and multilayers, and its role in creating environments suitable for chemical catalysis, (2) a possible role of extraterrestrial delivery of organics in the formation of the simplest bioenergetics (3) mechanisms leading from amino acids or their precursors to simple peptides and, subsequently, to the evolution of metabolism. These issues will be discussed from two opposite points of view: (1) Which molecules could have been particularly useful in the protobiological evolution; this may provide focus for searching for these molecules in interstellar media. (2) Assuming that a considerable part of the inventory of organic matter on the early earth was delivered extraterrestrially, what does relative abundance of different organics in space tell us about the scenario leading to the origin of life.

  14. The Nomad Explorer assembly assist vehicle: An architecture for rapid global extraterrestrial base infrastructure establishment

    Science.gov (United States)

    Thangavelu, Madhu

    1994-01-01

    Traditional concepts of lunar bases describe scenarios where components of the bases are landed on the lunar surface, one at a time, and then put together to form a complete stationary lunar habitat. Recently, some concepts have described the advantages of operating a mobile or 'roving' lunar base. Such a base vastly improves the exploration range from a primary lunar base. Roving bases would also allow the crew to first deploy, test, operationally certify, and then regularly maintain, service, and evolve long life-cycle facilities like observatories or other science payload platforms that are operated far apart from each other across the extraterrestrial surface. The Nomad Explorer is such a mobile lunar base. This paper describes the architectural program of the Nomad Explorer, its advantages over a stationary lunar base, and some of the embedded system concepts which help the roving base to speedily establish a global extraterrestrial infrastructure. A number of modular autonomous logistics landers will carry deployable or erectable payloads, service, and logistically resupply the Nomad Explorer at regular intercepts along the traverse. Starting with the deployment of science experiments and telecommunication networks, and the manned emplacement of a variety of remote outposts using a unique EVA Bell system that enhances manned EVA, the Nomad Explorer architecture suggests the capability for a rapid global development of the extraterrestrial body. The Moon and Mars are candidates for this 'mission oriented' strategy. The lunar case is emphasized in this paper.

  15. DCC-GARCH-CVaR模型与中国外汇储备结构动态优化

    Institute of Scientific and Technical Information of China (English)

    马杰; 张灿

    2012-01-01

    在欧美债务危机不断发酵与国际金融环境持续动荡中,如何通过资产结构连续调整来缓解中国3.3万亿外汇储备价值缩水,是我国急需解决的现实技术问题。本文构建了新的“DCC—GARCH-CVaR”优化模型,从三方面作了改进:利用DCC—GARCH模型度量方差协方差矩阵;采用可刻画超额损失的CVaR模型来度量风险;将不可比货币收益转换为可比收益。以2002年1月-2011年3月期间利率与汇率数据为样本,分别对“不考虑贸易外债结构等约束的无约束情况”和“在贸易外债等结构约束条件下”的最优外储结构调整问题展开研究。研究表明,与以往许多研究不同,无论是否施加结构约束,中国最优外汇储备结构均具有明显时变特征。本文还得到了一些相当有趣的发现,如欧元等资产与美元之间确实有“跷跷板”效应,预期最低组合收益变化对外储最优结构影响力十分有限,英镑与日元仍应在中国外汇储备中占有一席之地等。

  16. 基于Clayton Copula-GARCH模型投资组合VaR的度量%Estimation of Portfolio VaR under Clayton Copula-GARCH model

    Institute of Scientific and Technical Information of China (English)

    李明; 刘喜波; 何慧; 姚沛

    2013-01-01

    运用Copula方法研究了含股指期货的投资组合的风险度量问题.首先采用不同的GARCH模型对单个资产收益率建模,然后选择Clayton Copula函数来描述投资组合各资产之间的相关结构,建立联合分布模型,进而采用Monte Carlo方法模拟产生各资产的收益率序列,计算出投资组合的VaR.Kupiec检验表明,ClaytonCopula-GARCH模型在投资组合风险度量上具有较高的准确性.%In this paper,we use Copula method to measure VaR of portfolio which contain stock index futures.First,choose different GARCH models to fit each asset return series,second,select Clayton Copula function to describe the relational structure between each asset of the portfolio and build joint distribution model,third,use Monte Carlo method to produce each return sequence of the assets,and then calculate VaR of the portfolio.Kupiec inspection showed that the VaR measure method based on Clayton Copula-GARCH model is effective.

  17. Estimating 'Value at Risk' of crude oil price and its spillover effect using the GED-GARCH approach

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Ying; Wei, Yi-Ming [Center for Energy and Environmental Policy Research, Institute of Policy and Management, Chinese Academy of Sciences, Beijing, 100080 (China); Zhang, Yue-Jun [Center for Energy and Environmental Policy Research, Institute of Policy and Management, Chinese Academy of Sciences, Beijing, 100080 (China); Graduate University of the Chinese Academy of Sciences, Beijing, 100080 (China); Tsai, Hsien-Tang [College of Management, National Sun Yat-sen University, Kaohsiung 80424 (China)

    2008-11-15

    Estimation has been carried out using GARCH-type models, based on the Generalized Error Distribution (GED), for both the extreme downside and upside Value-at-Risks (VaR) of returns in the WTI and Brent crude oil spot markets. Furthermore, according to a new concept of Granger causality in risk, a kernel-based test is proposed to detect extreme risk spillover effect between the two oil markets. Results of an empirical study indicate that the GED-GARCH-based VaR approach appears more effective than the well-recognized HSAF (i.e. historical simulation with ARMA forecasts). Moreover, this approach is also more realistic and comprehensive than the standard normal distribution-based VaR model that is commonly used. Results reveal that there is significant two-way risk spillover effect between WTI and Brent markets. Supplementary study indicates that at the 99% confidence level, when negative market news arises that brings about a slump in oil price return, historical information on risk in the WTI market helps to forecast the Brent market. Conversely, it is not the case when positive news occurs and returns rise. Historical information on risk in the two markets can facilitate forecasts of future extreme market risks for each other. These results are valuable for anyone who needs evaluation and forecasts of the risk situation in international crude oil markets. (author)

  18. 基于Realized GARCH模型的沪深300指数波动率研究%Shanghai-Shenzhen 300 Index Volatility Study Based on Realized GARCH Model

    Institute of Scientific and Technical Information of China (English)

    关璐; 郭名媛

    2016-01-01

    Based on Chinese Shanghai-Shenzhen 300 Index and use the 5 minutes high frequency data to calculate and take the realized range as the volatility estimated value.Establish the Realized GARCH model and assume the yield rate residual error respectively obey the normal distribution and generalized hyperbol-ic distribution.Empirical results show that no matter take realized variance or realized range as the realized measure,the fitting results of Realized GARCH model that obey the generalized hyperbolic distribution is always better than it of Realized GARCH model that obey the normal distribution.No matter the residual error obeys the normal distribution or generalized hyperbolic distribution,the fitting results of Realized GARCH model that take realized range as the realized measure is always better than it of Realized GARCH model that take realized variance as the realized measure.On the other hand,in the term of improvement of likelihood value,changing the volatility estimated value will bring out higher improvement of likelihood value than changing residual error distribution,it means that select a appropriate volatility estimated value has significant influence on the fitting results of Realized GARCH model.%基于中国沪深300指数,采用5 min 高频数据计算已实现极差作为波动率估计量。建立Realized GARCH 模型,并假设收益率残差分别服从正态分布和广义双曲线分布。实证结果表明:无论是选择已实现方差还是已实现极差作为已实现测度,服从广义双曲线分布的 Realized GARCH模型拟合效果都比服从正态分布的Realized GARCH 模型要好。无论残差服从广义双曲线分布还是正态分布,采用已实现极差作为已实现测度的Realized GARCH 模型的拟合效果都比采用已实现方差作为已实现测度的Realized GARCH 模型要好。另一方面,从似然值提高的程度来看,改变波动率估计量比改变残差分布带来更大的似然值提

  19. Assessing Geologic Image Interpretation Errors Occurring in Extraterrestrial Robotic Exploration

    Science.gov (United States)

    Wagner, J.; Anderson, R. C.; Thomas, G.; Cabrol, N.; Grin, E.; Glasgow, J.

    2003-12-01

    Robotic exploration of the Martian surface requires numerous interpretations of imaged data, where incorrect results can have drastic consequences. The imaging process transforms and reduces the amount of information available. Three experiments measured the differences in interpretation between imaged sediments and physical sediments. Three characteristics were analyzed: grain length, grain shape, and grain distribution. The results found the difference between the grain length measured on an image and the true length to +/- 2.333 pixels (p <0.0001); the difference is similar to the amount of blurring introduced by the camera. Both grain roundness and grain sphericity were classified on a scale from 1 to 6 in the shape experiment. The roundness classification differed by 0.114 categories (p = 0.0082) with the imaged grains being rounder. The sphericity classification differed by 0.151 categories (p = 0.0010) with the imaged grains being less spherical. In the distribution experiment, the subjects determined the percentage of the total image area covered by grains in six specified size ranges. The average error for each size range was 11.112 % of the total area (p < 0.0001). In all three experiments, the measurements taken using the imaged specimens significantly differed from the measurements taken using the physical specimens. The magnitudes of the differences were small and may not be scientifically significant.

  20. The probability of extraterrestrial life; La probabilidad de vida extraterrestre

    Energy Technology Data Exchange (ETDEWEB)

    Chavez B, A

    1991-06-15

    Since beginning of times, human beings need to live in the company of other humans, beings developing what we now know as human societies. According to this idea there has been speculation, specially in the present century, about the possibility that human society has company of the other thinking creatures living in other planets somewhere in our galaxy. In this talk we will only use reliable data from scientific observers in order to establish a probability. We will explain the analysis on the physico-chemical principles which allow the evolution of organic molecules in our planet and establish these as the forerunners of life in our planet. On the other hand, the physical process governing stars, their characteristics and their effects on planets will also be explained as well as the amount of energy that a planet receives, its mass, atmosphere and kind of orbit. Finally, considering all this information, a probability of life from outer space will be given. (Author)

  1. Glossary to ARCH (GARCH)

    DEFF Research Database (Denmark)

    Bollerslev, Tim

    The literature on modeling and forecasting time-varying volatility is ripe with acronyms and abbreviations used to describe the many different parametric models that have been put forth since the original linear ARCH model introduced in the seminal Nobel Prize winning paper by Engle (1982......).  The present paper provides an easy-to-use encyclopedic reference guide to this long list of ARCH acronyms.  In addition to the acronyms associated with specific parametric models, I have also included descriptions of various abbreviations associated with more general statistical procedures and ideas...

  2. Glossary to ARCH (GARCH)

    DEFF Research Database (Denmark)

    Bollerslev, Tim

    The literature on modeling and forecasting time-varying volatility is ripe with acronyms and abbreviations used to describe the many different parametric models that have been put forth since the original linear ARCH model introduced in the seminal Nobel Prize winning paper by Engle (1982......).  The present paper provides an easy-to-use encyclopedic reference guide to this long list of ARCH acronyms.  In addition to the acronyms associated with specific parametric models, I have also included descriptions of various abbreviations associated with more general statistical procedures and ideas...

  3. Wind Power Forecasting Base on ARMAX-GARCH for a Microgrid%基于ARMAX-GARCH模型的微电网风功率预测

    Institute of Scientific and Technical Information of China (English)

    黄磊; 舒杰; 崔琼; 姜桂秀

    2013-01-01

    目前风功率预测多为风功率期望的点预测,且以采样间隑较大的功率序列作为建模序列,这样会降低预测模型对风功率时序特征模拟的准确度和可信度。文中基于小采样间隑风功率序列,提出 ARMAX-GARCH 风功率预测模型。通过构造风功率新息序列,结合小时平均风功率序列,建立ARMAX点预测模型,采用BIC最小信息准则和相关性分析实现模型定阶和外生变量选择;采用GARCH模型模拟残差的波动特性实现区间预测。以海岛微电网实测风功率数据为例,迚行提前1 h风功率预测。结果表明,与持续法、ARMA和RBF神经网络相比,该预测模型能显著提高风功率期望的点预测精度幵具有较好的区间预测效果。%Wind power forecasting models are often built for point forecasting using wind power series with large sampling intervals, which reduces the accuracy and reliability of the forecasting models. Based on wind power series with small sampling interval, this paper proposes an ARMAX-GARCH wind power forecasting model. The ARMAX model is built for point forecasting by combining the constructed innovation series of wind power and the hourly-average wind power series. The model identification and exogenous covariates selection are based on Bayesian information criterion (BIC) and correlation analysis. The GARCH model is used for interval forecasting to simulate the fluctuation characteristic of the residual series. To demonstrate the effectiveness, the model for 1 h ahead forecasting is applied and tested on a microgrid located on an island in the south of China. Comparing with persistent method, ARMA and RBF neural network, simulation results demonstrate that the proposed forecasting model improves the accuracy of point forecasting significantly and has a better interval forecasting result.

  4. Titan Submarine : AUV Design for Cryogenic Extraterrestrial Seas of Hydrocarbons

    Science.gov (United States)

    Lorenz, Ralph D.; Oleson, Steven; Colozza, Tony; Hartwig, Jason; Schmitz, Paul; Landis, Geoff; Paul, Michael; Walsh, Justin

    2016-04-01

    to date, which brought together power/propulsion/space systems expertise from NASA Glenn Research Center, with hydrodynamics, propulsion and operations from the Penn State Applied Research Lab, and the latest Titan understanding from the JHU Applied Physics Lab.

  5. Mainstream Media and Social Media Reactions to the Discovery of Extraterrestrial Life

    Science.gov (United States)

    Jones, Morris

    The rise of online social media (such as Facebook and Twitter) has overturned traditional top-down and stovepiped channels for mass communications. As social media have risen, traditional media sources have been steadily crippled by economic problems, resulting in a loss of capabilities and credibility. Information can propagate rapidly without the inclusion of traditional editorial checks and controls. Mass communications strategies for any type of major announcement must account for this new media landscape. Scientists announcing the discovery of extraterrestrial life will trigger a multifaceted and unpredictable percolation of the story through the public sphere. They will also potentially struggle with misinformation, rumours and hoaxes. The interplay of official announcements with the discussions of an extraterrestrial discovery on social media has parallels with traditional theories of mass communications. A wide spectrum of different messages is likely to be received by different segments of the community, based on their usage patterns of various media and online communications. The presentation and interpretation of a discovery will be hotly debated and contested within online media environments. In extreme cases, this could lead to "editorial wars" on collaborative media projects as well as cyber-attacks on certain online services and individuals. It is unlikely that a clear and coherent message can be propagated to a near-universal level. This has the potential to contribute to inappropriate reactions in some sectors of the community. Preventing unnecessary panic will be a priority. In turn, the monitoring of online and social media will provide a useful tool for assessing public reactions to a discovery of extraterrestrial life. This will help to calibrate public communications strategies following in the wake of an initial announcement.

  6. What should we say to extraterrestrial intelligence?: An analysis of responses to “Earth Speaks”

    Science.gov (United States)

    Vakoch, Douglas A.; Lower, Timothy A.; Niles, Britton A.; Rast, Katrina A.; DeCou, Christopher

    2013-05-01

    If scientists engaged in the Search for Extraterrestrial Intelligence (SETI) detect a signal from an extraterrestrial civilization, one of the most pressing issues facing humankind will be "Should we reply, and if so, what should we say?" Building on an infrastructure that the SETI Institute used to gather over 50,000 messages from around the world to send onboard the Kepler mission, Earth Speaks invites people to submit online their text messages, pictures, and sounds, as they ponder what they would want to say to an extraterrestrial civilization. Participants for the study have been recruited from 68 nations, from all walks of life. By tracking demographic variables for each person submitting a message, we have identified commonalities and differences in message content that are related to such factors as age and gender. Similarly, by tracking the date on which messages were submitted and the location from which the message was sent, we have also identified the way in which message content is related to time and geographic location. Furthermore, when we compare previous themes derived from textual messages to our current categorical analysis of submitted images, we find our textual themes to be concurrently validated. In doing so, we find the Earth Speaks Website not only allows for the construction of interstellar messages, but also functions as a projective psychological assessment of species-level human identity. We next proceed to demonstrate the generative power of our method by showing how we can synthesize artificial messages from the Earth Speaks messages. We then discuss how these artificially generated messages can be tailored to represent both commonality and diversity in human thought as it is revealed through our data. We end by discussing our method's utility for cross-disciplinary research in the social sciences and humanities.

  7. The asymmetric reactions of mean and volatility of stock returns to domestic and international information based on a four-regime double-threshold GARCH model

    Science.gov (United States)

    Chen, Cathy W. S.; Yang, Ming Jing; Gerlach, Richard; Jim Lo, H.

    2006-07-01

    In this paper, we investigate the asymmetric reactions of mean and volatility of stock returns in five major markets to their own local news and the US information via linear and nonlinear models. We introduce a four-regime Double-Threshold GARCH (DTGARCH) model, which allows asymmetry in both the conditional mean and variance equations simultaneously by employing two threshold variables, to analyze the stock markets’ reactions to different types of information (good/bad news) generated from the domestic markets and the US stock market. By applying the four-regime DTGARCH model, this study finds that the interaction between the information of domestic and US stock markets leads to the asymmetric reactions of stock returns and their variability. In addition, this research also finds that the positive autocorrelation reported in the previous studies of financial markets may in fact be mis-specified, and actually due to the local market's positive response to the US stock market.

  8. Estimating risk of foreign exchange portfolio: Using VaR and CVaR based on GARCH-EVT-Copula model

    Science.gov (United States)

    Wang, Zong-Run; Chen, Xiao-Hong; Jin, Yan-Bo; Zhou, Yan-Ju

    2010-11-01

    This paper introduces GARCH-EVT-Copula model and applies it to study the risk of foreign exchange portfolio. Multivariate Copulas, including Gaussian, t and Clayton ones, were used to describe a portfolio risk structure, and to extend the analysis from a bivariate to an n-dimensional asset allocation problem. We apply this methodology to study the returns of a portfolio of four major foreign currencies in China, including USD, EUR, JPY and HKD. Our results suggest that the optimal investment allocations are similar across different Copulas and confidence levels. In addition, we find that the optimal investment concentrates on the USD investment. Generally speaking, t Copula and Clayton Copula better portray the correlation structure of multiple assets than Normal Copula.

  9. Testing for Expected Return and Market Price of Risk in Chinese A-B Share Market: A Geometric Brownian Motion and Multivariate GARCH Model Approach

    DEFF Research Database (Denmark)

    Zhu, Jie

    There exist dual-listed stocks which are issued by the same company in some stock markets. Although these stocks bare the same firm-specific risk and enjoy identical dividends and voting policies, they are priced differently. Some previous studies show this seeming deviation from the law of one...... price can be solved due to different ex- pected return and market price of risk for investors holding heterogeneous beliefs. This paper provides empirical evidence for that argument by testing the expected return and market price of risk between Chinese A and B shares listed in Shanghai and Shenzhen...... stock markets. Models with dynamic of Geometric Brownian Motion are adopted, multivariate GARCH models are also introduced to capture the feature of time-varying volatility in stock returns. The results suggest that the different pric- ing can be explained by the difference in expected returns between...

  10. Testing for Expected Return and Market Price of Risk in Chinese A-B Share Market: A Geometric Brownian Motion and Multivariate GARCH Model Approach

    DEFF Research Database (Denmark)

    Zhu, Jie

    There exist dual-listed stocks which are issued by the same company in some stock markets. Although these stocks bare the same firm-specific risk and enjoy identical dividends and voting policies, they are priced differently. Some previous studies show this seeming deviation from the law of one...... price can be solved due to different ex- pected return and market price of risk for investors holding heterogeneous beliefs. This paper provides empirical evidence for that argument by testing the expected return and market price of risk between Chinese A and B shares listed in Shanghai and Shenzhen...... stock markets. Models with dynamic of Geometric Brownian Motion are adopted, multivariate GARCH models are also introduced to capture the feature of time-varying volatility in stock returns. The results suggest that the different pric- ing can be explained by the difference in expected returns between...

  11. Distribución condicional de los retornos de la tasa de cambio colombiana: un ejercicio empírico a partir de modelos GARCH univariados.

    Directory of Open Access Journals (Sweden)

    Santiago Gallón Gómez

    2010-05-01

    Full Text Available Un conjunto de modelos GARCH multivariados son estimados y su validez empírica comparada a partir del cálculo de la medida VaR, para los retornos diarios de la tasa de cambio nominal del peso colombiano con respecto al dólar americano, euro, libra esterlina y yen japonés en el periodo 1999–2005. La comparación de las estimaciones para la matriz de covarianza condicional y los resultados obtenidos para la proporción de fallo y el contraste de cuantil dinámico de Engle y Manganelli (2004 presentan evidencia a favor del modelo de correlación condicional constante.

  12. Impact event at the Permian-Triassic boundary: evidence from extraterrestrial noble gases in fullerenes.

    Science.gov (United States)

    Becker, L; Poreda, R J; Hunt, A G; Bunch, T E; Rampino, M

    2001-02-23

    The Permian-Triassic boundary (PTB) event, which occurred about 251.4 million years ago, is marked by the most severe mass extinction in the geologic record. Recent studies of some PTB sites indicate that the extinctions occurred very abruptly, consistent with a catastrophic, possibly extraterrestrial, cause. Fullerenes (C60 to C200) from sediments at the PTB contain trapped helium and argon with isotope ratios similar to the planetary component of carbonaceous chondrites. These data imply that an impact event (asteroidal or cometary) accompanied the extinction, as was the case for the Cretaceous-Tertiary extinction event about 65 million years ago.

  13. Would contact with extraterrestrials benefit or harm humanity? A scenario analysis

    CERN Document Server

    Baum, Seth D; Domagal-Goldman, Shawn D; 10.1016/j.actaastro.2010.10.012

    2011-01-01

    While humanity has not yet observed any extraterrestrial intelligence (ETI), contact with ETI remains possible. Contact could occur through a broad range of scenarios could occur that have varying consequences for humanity. However, many discussions of this question assume that contact will follow a particular scenario that derives from the hopes and fears of the author. In this paper, we analyze a broad range of contact scenarios in terms of whether contact with ETI would benefit or harm humanity. This type of broad analysis can help us prepare for actual contact with ETI even if the details of contact do not fully resemble any specific scenario.

  14. The detection of extra-terrestrial life and the consequences for science and society.

    Science.gov (United States)

    Dominik, Martin; Zarnecki, John C

    2011-02-13

    Astronomers are now able to detect planets orbiting stars other than the Sun where life may exist, and living generations could see the signatures of extra-terrestrial life being detected. Should it turn out that we are not alone in the Universe, it will fundamentally affect how humanity understands itself--and we need to be prepared for the consequences. A Discussion Meeting held at the Royal Society in London, 6-9 Carlton House Terrace, on 25-26 January 2010, addressed not only the scientific but also the societal agenda, with presentations covering a large diversity of topics.

  15. Strategic considerations in SETI, and a microwave approach. [Search for ExtraTerrestrial Intelligence

    Science.gov (United States)

    Seeger, C. L.

    1977-01-01

    Plausible options in the search for extraterrestrial intelligence (SETI), and the need to reserve a suitable portion of the EM (microwave) spectrum for SETI research, are discussed. Reasons for selection of a portion of the spectrum, specifically the 'water hole' near 1.5 GHz in the terrestrial microwave window (1-25 GHz), are presented, and competition with various emitters for that band (existing satellite downlink transmissions) is discussed. SETI search policies and options are summarized in a table. Speculative considerations guiding initial phases of the SETI pursuit are discussed.

  16. Amino Acids from Icy Amines: A Radiation-Chemical Approach to Extraterrestrial Synthesis

    Science.gov (United States)

    Dworkin, J. P.; Moore, M. H.

    2010-01-01

    Detections of amino acids in meteorites go back several decades, with at least 100 such compounds being reported for the Murchison meteorite alone. The presence of these extraterrestrial molecules raises questions as to their formation, abundance, thermal stability, racemization, and possible subsequent reactions. Although all of these topics have been studied in laboratories, such work often involves many variables and unknowns. This has led us to seek out model systems with which to uncover reaction products, test chemical predictions, and sited light on underlying reaction mechanisms. This presentation will describe one such study, focusing on amino-acid formation in ices.

  17. 基于GARCH族模型的我国股市波动性分析%Analysis on the Volatility of Chinese Stock Market Based on GARCH Model

    Institute of Scientific and Technical Information of China (English)

    汤祥凤

    2016-01-01

    Taking Shanghai composite index and Shenzhen component index as the study obj ects,using GARCH class models of Shanghai and Shenzhen,the empirical analysis research has been carried on about volatility of asymmetry and volatility spillover effect,the empirical result shows that:(1)There is a sig-nificant role effect of the ARCH in the two cities,Shenzhen being at more risk on premium than in Shang-hai;(2 )There is a significant leverage effect showing a stronger fluctuation from bad news than good news in Shanghai and Shenzhen markets;(3)Both cities have one-way volatility spillover effect,and the fluctuations from Shanghai stock market can cause the fluctuations of Shenzhen.%以上证指数和深圳成指为研究对象,运用 GARCH 类模型对沪深两市的波动性、非对称性以及波动溢出效应进行了实证分析研究。实证表明:(1)两市存在显著的 ARCH 效应,且深市的风险溢价要高于沪市;(2)两市的杠杆效应较为显著,表明沪深市场上坏消息比好消息更能引起股市的剧烈波动;(3)两市存在单向的波动溢出效应,且沪市的波动会导致深市的波动。

  18. 50th Anniversary of the World's First Extraterrestrial Sample Receiving Laboratory: The Apollo Program's Lunar Receiving Laboratory

    Science.gov (United States)

    Calaway, M. J.; Allton, J. H.; Zeigler, R. A.; McCubbin, F. M.

    2017-01-01

    The Apollo program's Lunar Receiving Laboratory (LRL), building 37 at NASA's Manned Spaceflight Center (MSC), now Johnson Space Center (JSC), in Houston, TX, was the world's first astronaut and extraterrestrial sample quarantine facility (Fig. 1). It was constructed by Warrior Construction Co. and Warrior-Natkin-National at a cost of $8.1M be-tween August 10, 1966 and June 26, 1967. In 1969, the LRL received and curated the first collection of extra-terrestrial samples returned to Earth; the rock and soil samples of the Apollo 11 mission. This year, the JSC Astromaterials Acquisition and Curation Office (here-after JSC curation) celebrates 50 years since the opening of the LRL and its legacy of laying the foundation for modern curation of extraterrestrial samples.

  19. Exploring the Human Ecology of the Younger Dryas Extraterrestrial Impact Event

    Science.gov (United States)

    Kennett, D. J.; Erlandson, J. M.; Braje, T. J.; Culleton, B. J.

    2007-05-01

    Several lines of evidence now exist for a major extraterrestrial impact event in North America at 12.9 ka (the YDB). This impact partially destabilized the Laurentide and Cordilleran ice sheets, triggered abrupt Younger Dryas cooling and extensive wildfires, and contributed to megafaunal extinction. This event also occurred soon after the well established colonization of the Americas by anatomically modern humans. Confirmation of this event would represent the first near-time extraterrestrial impact with significant effects on human populations. These likely included widespread, abrupt human mortality, population displacement, migration into less effected or newly established habitats, loss of cultural traditions, and resource diversification in the face of the massive megafaunal extinction and population reductions in surviving animal populations. Ultimately, these transformations established the context for the special character of plant and animal domestication and the emergence of agricultural economies in North America. We explore the Late Pleistocene archaeological record in North America within the context of documented major biotic changes associated with the YDB in North America and of the massive ecological affects hypothesized for this event.

  20. Creatures in the Classroom: Preservice Teacher Beliefs About Fantastic Beasts, Magic, Extraterrestrials, Evolution and Creationism

    Science.gov (United States)

    Losh, Susan Carol; Nzekwe, Brandon

    2011-05-01

    Faculty have long expressed concern about pseudoscience belief among students. Most US research on such beliefs examines evolution-creation issues among liberal arts students, the general public, and occasionally science educators. Because of their future influence on youth, we examined basic science knowledge and several pseudoscience beliefs among 540 female and 123 male upperclass preservice teachers, comparing them with representative samples of comparably educated American adults. Future teachers resembled national adults on basic science knowledge. Their scores on evolution; creationism; intelligent design; fantastic beasts; magic; and extraterrestrials indices depended on the topic. Exempting science education, preservice teachers rejected evolution, accepting Biblical creation and intelligent design accounts. Sizable minorities "awaited more evidence" about fantastic beasts, magic, or extraterrestrials. Although gender, disciplinary major, grade point average, science knowledge, and two religiosity measures related to beliefs about evolution-creation, these factors were generally unassociated with the other indices. The findings suggest more training is needed for preservice educators in the critical evaluation of material evidence. We also discuss the judicious use of pseudoscience beliefs in such training.

  1. Habitability and the Possibility of Extraterrestrial Life in the Early Telescope Era

    Science.gov (United States)

    Reynolds, Sarah

    2014-01-01

    Early telescopic observations of the Moon and planets prompted great interest in the already-existing debate about the possibility of life on the Moon and other worlds. New observations of the lunar surface, revealing an apparently Earth-like terrain and possibly the presence of bodies of water, were often considered in relation to their implications for the existence of lunar inhabitants. This depended upon establishing what constituted the fundamental requirements for life and the boundaries of habitability. The growing support for the heliocentric Copernican astronomy was also changing perceptions of the relationships between the Earth, the Moon, and the planets. Works such as Johannes Kepler’s Somnium and John Wilkins’ The Discovery of a World in the Moone presented views of extraterrestrial life that were shifting from the supernatural to the natural, in correspondence with the celestial bodies’ new positions in the cosmos. This paper considers how these and other works from the early telescope era reveal changes in the nature of astronomical speculation about extraterrestrial life and the conditions construed as “habitability,” and what significance that history has for us today in the new era of extrasolar planet discovery.

  2. Isotopic evidence for extraterrestrial non-racemic amino acids in the Murchison meteorite.

    Science.gov (United States)

    Engel, M H; Macko, S A

    1997-09-18

    Many amino acids contain an asymmetric centre, occurring as laevorotatory, L, or dextrorotatory, D, compounds. It is generally assumed that abiotic synthesis of amino acids on the early Earth resulted in racemic mixtures (L- and D-enantiomers in equal abundance). But the origin of life required, owing to conformational constraints, the almost exclusive selection of either L- or D-enantiomers, and the question of why living systems on the Earth consist of L-enantiomers rather than D-enantiomers is unresolved. A substantial fraction of the organic compounds on the early Earth may have been derived from comet and meteorite impacts. It has been reported previously that amino acids in the Murchison meteorite exhibit an excess of L-enantiomers, raising the possibility that a similar excess was present in the initial inventory of organic compounds on the Earth. The stable carbon isotope compositions of individual amino acids in Murchison support an extraterrestrial origin -- rather than a terrestrial overprint of biological amino acids-although reservations have persisted. Here we show that individual amino-acid enantiomers from Murchison are enriched in 15N relative to their terrestrial counterparts, so confirming an extraterrestrial source for an L-enantiomer excess in the Solar System that may predate the origin of life on the Earth.

  3. FINDING EXTRATERRESTRIAL LIFE USING GROUND-BASED HIGH-DISPERSION SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Snellen, I. A. G.; Le Poole, R.; Brogi, M.; Birkby, J. [Leiden Observatory, Leiden University, Postbus 9513, 2300-RA Leiden (Netherlands); De Kok, R. J. [SRON, Sorbonnelaan 2, 3584-CA Utrecht (Netherlands)

    2013-02-20

    Exoplanet observations promise one day to unveil the presence of extraterrestrial life. Atmospheric compounds in strong chemical disequilibrium would point to large-scale biological activity just as oxygen and methane do in the Earth's atmosphere. The cancellation of both the Terrestrial Planet Finder and Darwin missions means that it is unlikely that a dedicated space telescope to search for biomarker gases in exoplanet atmospheres will be launched within the next 25 years. Here we show that ground-based telescopes provide a strong alternative for finding biomarkers in exoplanet atmospheres through transit observations. Recent results on hot Jupiters show the enormous potential of high-dispersion spectroscopy to separate the extraterrestrial and telluric signals, making use of the Doppler shift of the planet. The transmission signal of oxygen from an Earth-twin orbiting a small red dwarf star is only a factor of three smaller than that of carbon monoxide recently detected in the hot Jupiter {tau} Booetis b, albeit such a star will be orders of magnitude fainter. We show that if Earth-like planets are common, the planned extremely large telescopes can detect oxygen within a few dozen transits. Ultimately, large arrays of dedicated flux-collector telescopes equipped with high-dispersion spectrographs can provide the large collecting area needed to perform a statistical study of life-bearing planets in the solar neighborhood.

  4. Gaussian/non-Gaussian distributions and the identification of terrestrial and extraterrestrial intelligence objects

    Directory of Open Access Journals (Sweden)

    Sergey Haitun

    2015-06-01

    Full Text Available Statistical criteria used today in the analysis of radio signals suspected on reasonable extraterrestrial origin, are based on the assumption that all the radio signals of natural origin are described by a Gaussian distribution, which is traditionally understood as the Gauss distribution. Usually the normal (Gauss distribution is opposed to all the others. However, this is difficult to recognize the reasonable, because in nature there are many different distributions. The article offers a more realistic dichotomy: the Gaussian distributions, obeying the central limiting theorem, dominate in nature, while non-Gaussian ones, obeying the Gnedenko-Doeblin limiting theorem, are generated by intelligent beings. When identifying objects belonging to an extraterrestrial civilization described by a non-Gaussian distribution is preferable to use the rank form distributions. Using this criterion is associated with certain difficulties: (1 in nature there are also non-Gaussian distributions; (2 in their activities animals generate non-Gaussian distributions like humans; (3 the identification of non-Gaussian distributions in the rank form is hampered sometimes by the rank distortion effect of mathematical nature.

  5. The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. I. Background and Justification

    Science.gov (United States)

    Wright, J. T.; Mullan, B.; Sigurdsson, S.; Povich, M. S.

    2014-09-01

    We motivate the Ĝ infrared search for extraterrestrial civilizations with large energy supplies. We discuss some philosophical difficulties of the search for extraterrestrial intelligence (SETI), and how communication SETI circumvents them. We review "Dysonian SETI," the search for artifacts of alien civilizations, and find that it is highly complementary to traditional communication SETI; the two together might succeed where either one alone has not. We discuss the argument of Hart that spacefaring life in the Milky Way should be either galaxy-spanning or non-existent, and examine a portion of his argument that we call the "monocultural fallacy." We discuss some rebuttals to Hart that invoke sustainability and predict long Galaxy colonization timescales. We find that the maximum Galaxy colonization timescale is actually much shorter than previous work has found (counter-arguments to Hart's thesis suffer from the monocultural fallacy. We extend Hart's argument to alien energy supplies and argue that detectably large energy supplies can plausibly be expected to exist because life has the potential for exponential growth until checked by resources or other limitations, and intelligence implies the ability to overcome such limitations. As such, if Hart's thesis is correct, then searches for large alien civilizations in other galaxies may be fruitful; if it is incorrect, then searches for civilizations within the Milky Way are more likely to succeed than Hart argued. We review some past Dysonian SETI efforts and discuss the promise of new mid-infrared surveys, such as that of WISE.

  6. Prebiotic significance of extraterrestrial ice photochemistry: detection of hydantoin in organic residues.

    Science.gov (United States)

    de Marcellus, Pierre; Bertrand, Marylène; Nuevo, Michel; Westall, Frances; Le Sergeant d'Hendecourt, Louis

    2011-11-01

    The delivery of extraterrestrial organic materials to primitive Earth from meteorites or micrometeorites has long been postulated to be one of the origins of the prebiotic molecules involved in the subsequent apparition of life. Here, we report on experiments in which vacuum UV photo-irradiation of interstellar/circumstellar ice analogues containing H(2)O, CH(3)OH, and NH(3) led to the production of several molecules of prebiotic interest. These were recovered at room temperature in the semi-refractory, water-soluble residues after evaporation of the ice. In particular, we detected small quantities of hydantoin (2,4-imidazolidinedione), a species suspected to play an important role in the formation of poly- and oligopeptides. In addition, hydantoin is known to form under extraterrestrial, abiotic conditions, since it has been detected, along with various other derivatives, in the soluble part of organic matter of primitive carbonaceous meteorites. This result, together with other related experiments reported recently, points to the potential importance of the photochemistry of interstellar "dirty" ices in the formation of organics in Solar System materials. Such molecules could then have been delivered to the surface of primitive Earth, as well as other telluric (exo-) planets, to help trigger first prebiotic reactions with the capacity to lead to some form of primitive biomolecular activity.

  7. The G-HAT Search for Advanced Extraterrestrial Civilizations: The Reddest Extended WISE Sources

    Science.gov (United States)

    Maldonado, Jessica; Povich, Matthew S.; Wright, Jason; Griffith, Roger; Sigurdsson, Steinn; Mullan, Brendan L.

    2015-01-01

    Freeman Dyson (1960) theorized how to identify possible signatures of advanced extra-terrestrial civilizations by their waste heat, an inevitable byproduct of a civilization using a significant fraction of the luminosity from their host star. If a civilizations could tap the starlight throughout their host galaxy their waste heat would be easily detectable by recent infrared surveys. The Glimpsing Heat from Alien Technologies (G-HAT) pilot project aims to place limits on the existence of extraterrestrial civilizations at pan-galactic scales. We present results from the G-HAT cleaned catalog of 563 extremely red, extended high Galactic latitude (|b| ≥ 10) sources from the WISE All-Sky Catalog. Our catalog includes sources new to the scientific literature along with well-studied objects (e.g. starburst galaxies, AGN, and planetary nebulae) that exemplify extreme WISE colors. Objects of particular interest include a supergiant Be star (48 Librae) surrounded by a resolved, mid-infrared nebula, possibly indicating dust in the stellar wind ejecta, and a curious cluster of seven extremely red WISE sources (associated with IRAS 04287+6444) that have no optical counterparts.

  8. Understanding prebiotic chemistry through the analysis of extraterrestrial amino acids and nucleobases in meteorites.

    Science.gov (United States)

    Burton, Aaron S; Stern, Jennifer C; Elsila, Jamie E; Glavin, Daniel P; Dworkin, Jason P

    2012-08-21

    The discoveries of amino acids of extraterrestrial origin in many meteorites over the last 50 years have revolutionized the Astrobiology field. A variety of non-terrestrial amino acids similar to those found in life on Earth have been detected in meteorites. A few amino acids have even been found with chiral excesses, suggesting that meteorites could have contributed to the origin of homochirality in life on Earth. In addition to amino acids, which have been productively studied for years, sugar-like molecules, activated phosphates, and nucleobases have also been determined to be indigenous to numerous meteorites. Because these molecules are essential for life as we know it, and meteorites have been delivering them to the Earth since accretion, it is plausible that the origin(s) of life on Earth were aided by extraterrestrially-synthesized molecules. Understanding the origins of life on Earth guides our search for life elsewhere, helping to answer the question of whether biology is unique to Earth. This tutorial review focuses on meteoritic amino acids and nucleobases, exploring modern analytical methods and possible formation mechanisms. We will also discuss the unique window that meteorites provide into the chemistry that preceded life on Earth, a chemical record we do not have access to on Earth due to geologic recycling of rocks and the pervasiveness of biology across the planet. Finally, we will address the future of meteorite research, including asteroid sample return missions.

  9. Sources of Extraterrestrial Rare Earth Elements:To the Moon and Beyond

    Science.gov (United States)

    McLeod, C. L.; Krekeler, M. P. S.

    2017-08-01

    The resource budget of Earth is limited. Rare-earth elements (REEs) are used across the world by society on a daily basis yet several of these elements have up to 3% of the PKT. Other lunar REE-bearing lunar phases include monazite, yittrobetafite (up to 94,500 ppm yttrium), and tranquillityite (up to 4.6 wt % yttrium, up to 0.25 wt % neodymium), however, lunar sample REE abundances are low compared to terrestrial ores. At present, there is no geological, mineralogical, or chemical evidence to support REEs being present on the Moon in concentrations that would permit their classification as ores. However, the PKT region has not yet been mapped at high resolution, and certainly has the potential to yield higher REE concentrations at local scales (date, constituting <0.6% of the total sample. Nonetheless, they dominate a samples REE budget with their abundances typically 1-2 orders of magnitude enriched relative to their host rock. As with the Moon, though phases which host REEs have been identified, no extraterrestrial REE resource, or ore, has been identified yet. At present extraterrestrial materials are therefore not suitable REE-mining targets. However, they are host to other resources that will likely be fundamental to the future of space exploration and support the development of in situ resource utilization, for example: metals (Fe, Al, Mg, PGEs) and water.

  10. X-Ray Data on Extraterrestrial CA Dialuminate (CaAl4O7)

    Science.gov (United States)

    Weber, D.; Ross, C. R., II; Bischoff, A.

    1993-07-01

    After the first discovery of Ca-dialuminate (CaAl4O7) in Allende [1], in recent years this phase has been found in several carbonaceous chondrites. Ca- dialuminate is a major phase in Ca,Al-rich inclusions from ALH85085 (e.g., [2]) and a dominating phase in CAIs from Acfer 182 ([3,4]). X-ray data on Ca-dialuminate are known from synthetic (e.g., [5-8]; cell constants) and terrestrial CaAl4O7 ([9]; only d-spacings), but are not available from extraterrestrial Ca-dialuminate. We report here the results of the first X-ray study of extraterrestrial Ca- dialuminate. The data (Table 1) were obtained by microdiffraction using a Rigaku PSPC microdiffractometer at the Bayerisches Geoinstitut. Ni-filtered Cr radiation was used with a direct beam diameter of about 50 micrometers. This powder diffraction method allows in situ measurement of polycrystalline Ca- dialuminate in a thin section. The CaAl4O7-rich inclusion 022/9 described in [4], consisting of a ~200-micrometer-sized core of Ca-dialuminate surrounded by layers of melilite and Ca-pyroxene, was chosen for analysis. The polycrystalline core contains only a small number of tiny inclusions (especially perovskite) and is therefore an excellent candidate for an X-ray study. For determination of the d-spacings of Ca-dialuminate an external standard (Ag6Ge10P12) was used for detector calibration. A large number of reflections could be indexed based upon comparison with the X-ray pattern of synthetic CaAl4O7 available in the JCPDS compilation [7]. The comparison was simplified because of the high purity of CaAl4O7 in inclusion 022/9 [4], and suggests the same structure for synthetic and extraterrestrial Ca-dialuminate. For determination of lattice parameters (cell constants, cell volume) refinement calculations were made based on 14 reflections (Table 1). The data for extraterrestrial CaAl4O7 shown in Table 1 indicate a close similarity to those obtained for synthetic CaAl4O7. The cell constants a, b, and therefore the cell

  11. Extraterrestrial hydrogeology

    Science.gov (United States)

    Baker, Victor R.; Dohm, James M.; Fairén, Alberto G.; Ferré, Ty P. A.; Ferris, Justin C.; Miyamoto, Hideaki; Schulze-Makuch, Dirk

    2005-03-01

    Subsurface water processes are common for planetary bodies in the solar system and are highly probable for exoplanets (planets outside the solar system). For many solar system objects, the subsurface water exists as ice. For Earth and Mars, subsurface saturated zones have occurred throughout their planetary histories. Earth is mostly clement with the recharge of most groundwater reservoirs from ample precipitation during transient ice- and hot-house conditions, as recorded through the geologic and fossilized records. On the other hand, Mars is mostly in an ice-house stage, which is interrupted by endogenic-driven activity. This activity catastrophically drives short-lived hydrological cycling and associated climatic perturbations. Regional aquifers in the Martian highlands that developed during past, more Earth-like conditions delivered water to the northern plains. Water was also cycled to the South Polar Region during changes in climate induced by endogenic activity and/or by changes in Mars' orbital parameters. Venus very likely had a warm hydrosphere for hundreds of millions of years, before the development of its current extremely hot atmosphere and surface. Subsequently, Venus lost its hydrosphere as solar luminosity increased and a run-away moist greenhouse took effect. Subsurface oceans of water or ammonia-water composition, induced by tidal forces and radiogenic heating, probably occur on the larger satellites Europa, Ganymede, Callisto, Titan, and Triton. Tidal forces operating between some of the small bodies of the outer solar system could also promote the fusion of ice and the stability of inner liquid-water oceans. Les processus de subsurface impliquant l'eau sont communs pour les corps planétaires du système solaire et sont très probables sur les exoplanètes (planètes en dehors du système solaire). Pour plusieurs objets du systèmes solaire, l'eau de subsurface est présente sous forme de glace. Pour la Terre et Mars, les zones saturées de subsurface apparaissent à travers toute leur histoire planétaire. La Terre est particulièrement clémente avec la recharge des réservoirs, avec de amples précipitations, des conditions glaciaires et de fortes chaleurs, comme l'atteste les enregistrements géologiques et paléontologiques. D'un autre côté, Mars se trouve dans une phase essentiellement glaciaire, qui est interrompue par des activités contraintes par les phénomènes endogéniques. Cette activité conduit de manière catastrophique à des cycles hydrologiques et à des perturbations climatiques brutaux. Les aquifères régionaux dans les haute terres martiennes qui se sont formés dans des conditions similaires aux conditions terrestres, alimentent les plaines du Nord. L'eau a également été déplacée vers le Pôle Sud martien durant des changements marqués par une forte activité endogénique et une modification des paramètres de l'orbite de Mars. Venus possèdait vrais emblablement une hydrosphère chaude durant des millions d'année, avant le développement de son atmosphère et sa surface particulièrement chaude. Par après Venus a perdit son hydrosphère alors que la luminosité solaire augmentait et qu'une humidité liée à un effet de serre s'installait. Les océans de subsurface d'eau ou d'eau ammoniacale, induits par les forces de marée et le chauffage radiogénique, apparaissent probablement sur les satellites les plus importants (Europa, Ganymede, Callisto, Titan, Triton). Les forces de marée entre les petits corps externes du système solaire peuvent également occasionner la fusion de glace et la stabilité des océans internes d'eau liquide. Los procesos hídricos subsuperficiales son comunes en cuerpos planetarios del sistema solar y son altamente probables para exoplanetas (planetas fuera del sistema solar). Para muchos cuerpos del sistema solar, el agua subsuperficial existe como hielo. Para la Tierra y Marte han ocurrido zonas saturadas subsuperficiales a través de sus historias planetarias. La Tierra es principalmente generosa con la recarga de la mayoría de reservorios de aguas subterráneas a partir de amplia precipitación reconocida en condiciones transitorias calientes y heladas, tal y como aparece en los registros fósiles y geológicos. Por otro lado, Marte se encuentra principalmente en una etapade cámara de hielo la cual es interrumpida por actividad de tipo endogénico. Esta actividad pone en funcionamiento catastróficamente ciclos hidrológicos de vida corta y perturbaciones climáticas asociadas. Acuíferos regionales en las montañas de Marte que se desarrollaron en el pasado en condiciones similares a la Tierra distribuyen agua a las planicies del norte. El agua ha sido transportada hacia el sur de la región polar durante cambios en el clima inducidos por actividad endogénica y/o cambios en los parámetros orbitales de Marte. Venus muy probablemente tuvo una hidrósfera caliente durante cientos de millones de años, antes de que se desarrollara su atmósfera y superficie actual extremadamente caliente. Subsecuentemente, Venus perdió su hidrósfera a medida que la luminosidad solar aumentó y un efecto de invernadero húmedo escapatorio se llevó a cabo. Océanos subsuperficiales de composición agua o amoniaco-agua, inducidos por fuerzas de marea y calentamiento radiogénico, probablemente ocurren en los satélites más grandes como Europa, Ganimeda, Callisto, Titan y Triton. Las fuerzas de marea que operan entre los cuerpos pequeños del sistema solar externo podrían también promover la fusión de hielo y la estabilidad de líquido interno-aguas de los océanos.

  12. EXTRATERRESTRIAL GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>20070001 Liang Ying (State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China); Wang Henian Petrology-Mineralogy and Classification of Eleven Ordinary Chondrites from the Grove Mountains in Antarctica (Geological Journal of China Universities, ISSN1006-7493, CN32-1440/P,12(1), 2006, p.53-61, 6 illus., 4 tables, 21 refs.) Key words: meteorites, Antarctica

  13. Prediction of Stock Return Rate and Relationship Between Risk and Return——Based on ARMA-GARCH Model and High-frequency Data%股票收益率预测及风险与收益关系研究——基于ARMA-GARCH模型和高频数据

    Institute of Scientific and Technical Information of China (English)

    张银雪; 杨德平; 李聪

    2013-01-01

    By using the high-frequency data of the CSI 300 index, ARMA model and GARCH(1 ,1)-T model are applied to fit and forecast the rate of return. In addition, GARCH-M model is selected to measure the relationship between risk and return. Experimental results show that the change of return rate has the feature with conditional heteroskedasticity; ARMA model is suitable for the long term prediction and GARCH(1,1)-T model is suitable for the short term prediction; As risk and return don't present positive relationship, our stock market isn't ripe.%以沪深300指数的—分钟为间隔的实时价格为研究样本,利用ARMA模型和基于T分布的GARCH(1,1)模型,对其收益率进行了拟合和预测,同时运用GARCH-M模型,分析风险和收益之间的关系.研究表明,股指波动存在条件异方差性;ARMA模型长期预测效果较好,而GARCH(1,1)-T模型短期预测效果较好;沪深300指数的风险和收益不呈正比,说明我国股市发展不成熟.

  14. Neutrino Physics with JUNO

    CERN Document Server

    An, Fengpeng; An, Qi; Antonelli, Vito; Baussan, Eric; Beacom, John; Bezrukov, Leonid; Blyth, Simon; Brugnera, Riccardo; Avanzini, Margherita Buizza; Busto, Jose; Cabrera, Anatael; Cai, Hao; Cai, Xiao; Cammi, Antonio; Cao, Guofu; Cao, Jun; Chang, Yun; Chen, Shaomin; Chen, Shenjian; Chen, Yixue; Chiesa, Davide; Clemenza, Massimiliano; Clerbaux, Barbara; Conrad, Janet; D'Angelo, Davide; De Kerret, Herve; Deng, Zhi; Deng, Ziyan; Ding, Yayun; Djurcic, Zelimir; Dornic, Damien; Dracos, Marcos; Drapier, Olivier; Dusini, Stefano; Dye, Stephen; Enqvist, Timo; Fan, Donghua; Fang, Jian; Favart, Laurent; Ford, Richard; Goger-Neff, Marianne; Gan, Haonan; Garfagnini, Alberto; Giammarchi, Marco; Gonchar, Maxim; Gong, Guanghua; Gong, Hui; Gonin, Michel; Grassi, Marco; Grewing, Christian; Guan, Mengyun; Guarino, Vic; Guo, Gang; Guo, Wanlei; Guo, Xin-Heng; Hagner, Caren; Han, Ran; He, Miao; Heng, Yuekun; Hsiung, Yee; Hu, Jun; Hu, Shouyang; Hu, Tao; Huang, Hanxiong; Huang, Xingtao; Huo, Lei; Ioannisian, Ara; Jeitler, Manfred; Ji, Xiangdong; Jiang, Xiaoshan; Jollet, Cecile; Kang, Li; Karagounis, Michael; Kazarian, Narine; Krumshteyn, Zinovy; Kruth, Andre; Kuusiniemi, Pasi; Lachenmaier, Tobias; Leitner, Rupert; Li, Chao; Li, Jiaxing; Li, Weidong; Li, Weiguo; Li, Xiaomei; Li, Xiaonan; Li, Yi; Li, Yufeng; Li, Zhi-Bing; Liang, Hao; Lin, Guey-Lin; Lin, Tao; Lin, Yen-Hsun; Ling, Jiajie; Lippi, Ivano; Liu, Dawei; Liu, Hongbang; Liu, Hu; Liu, Jianglai; Liu, Jianli; Liu, Jinchang; Liu, Qian; Liu, Shubin; Liu, Shulin; Lombardi, Paolo; Long, Yongbing; Lu, Haoqi; Lu, Jiashu; Lu, Jingbin; Lu, Junguang; Lubsandorzhiev, Bayarto; Ludhova, Livia; Luo, Shu; Lyashuk, Vladimir; Mollenberg, Randolph; Ma, Xubo; Mantovani, Fabio; Mao, Yajun; Mari, Stefano M; McDonough, William F; Meng, Guang; Meregaglia, Anselmo; Meroni, Emanuela; Mezzetto, Mauro; Miramonti, Lino; Mueller, Thomas; Naumov, Dmitry; Oberauer, Lothar; Ochoa-Ricoux, Juan Pedro; Olshevskiy, Alexander; Ortica, Fausto; Paoloni, Alessandro; Peng, Haiping; Peng, Jen-Chieh; Previtali, Ezio; Qi, Ming; Qian, Sen; Qian, Xin; Qian, Yongzhong; Qin, Zhonghua; Raffelt, Georg; Ranucci, Gioacchino; Ricci, Barbara; Robens, Markus; Romani, Aldo; Ruan, Xiangdong; Ruan, Xichao; Salamanna, Giuseppe; Shaevitz, Mike; Sinev, Valery; Sirignano, Chiara; Sisti, Monica; Smirnov, Oleg; Soiron, Michael; Stahl, Achim; Stanco, Luca; Steinmann, Jochen; Sun, Xilei; Sun, Yongjie; Taichenachev, Dmitriy; Tang, Jian; Tkachev, Igor; Trzaska, Wladyslaw; van Waasen, Stefan; Volpe, Cristina; Vorobel, Vit; Votano, Lucia; Wang, Chung-Hsiang; Wang, Guoli; Wang, Hao; Wang, Meng; Wang, Ruiguang; Wang, Siguang; Wang, Wei; Wang, Yi; Wang, Yifang; Wang, Zhe; Wang, Zheng; Wang, Zhigang; Wang, Zhimin; Wei, Wei; Wen, Liangjian; Wiebusch, Christopher; Wonsak, Bjorn; Wu, Qun; Wulz, Claudia-Elisabeth; Wurm, Michael; Xi, Yufei; Xia, Dongmei; Xie, Yuguang; Xing, Zhi-zhong; Xu, Jilei; Yan, Baojun; Yang, Changgen; Yang, Chaowen; Yang, Guang; Yang, Lei; Yang, Yifan; Yao, Yu; Yegin, Ugur; Yermia, Frederic; You, Zhengyun; Yu, Boxiang; Yu, Chunxu; Yu, Zeyuan; Zavatarelli, Sandra; Zhan, Liang; Zhang, Chao; Zhang, Hong-Hao; Zhang, Jiawen; Zhang, Jingbo; Zhang, Qingmin; Zhang, Yu-Mei; Zhang, Zhenyu; Zhao, Zhenghua; Zheng, Yangheng; Zhong, Weili; Zhou, Guorong; Zhou, Jing; Zhou, Li; Zhou, Rong; Zhou, Shun; Zhou, Wenxiong; Zhou, Xiang; Zhou, Yeling; Zhou, Yufeng; Zou, Jiaheng

    2015-01-01

    The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy as a primary physics goal. It is also capable of observing neutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, solar neutrinos, as well as exotic searches such as nucleon decays, dark matter, sterile neutrinos, etc. We present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. By detecting reactor antineutrinos from two power plants at 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4 sigma significance with six years of running. The measurement of antineutrino spectrum will also lead to the precise determination of three out of the six oscillation parameters to an accuracy of better than 1\\%. Neutrino burst from a typical cor...

  15. Research on volatility of public opinion of coal mine safety incidents based on GARCH model%基于GARC H类模型的煤矿安全事件舆情波动性研究∗

    Institute of Scientific and Technical Information of China (English)

    张华; 杨雪; 李松华; 王菲

    2015-01-01

    GARCH econometric model is used to analyze volatility characteristics of public o-pinion evolution of coal mine safety incidents. Based on an empirical study on weekly average data of coal mine incidents from January 1,2011 to May 16,2014 in Baidu search index,it can be found that:the volatility of public opinion evolution of coal mine safety incidents shows aggrega-tion effect;the model residual error is examined by ARCH effect,and it shows that the volatility of coal mine incidents search index has ARCH effect. Therefore,GARCH model is applicable to the study on the volatility of public opinion evolution of coal mine safety incidents,and the model results can provide prerequisite information for the warning of public opinion of coal mine safety incidents.%运用GARCH 类计量经济学模型,分析了煤矿安全事件舆情演化的波动性特征,基于2011年1月1日-2014年5月16日的煤矿事故百度搜索指数的周平均数据的实证研究发现:煤矿安全事件舆情演化的波动性呈现出聚集效应;通过对模型残差进行条件异方差即ARCH 效应检验,发现煤矿事故搜索指数的波动性具有ARCH 效应,因此,对煤矿安全事件舆情演化波动性的研究适用 GARCH 类模型,模型结果可以为煤矿安全事件舆情的预警提供先决信息。

  16. 二元GED-GARCH模型的利率与汇率波动溢出效应研究%Spillover Effects between Exchange Rate and Interest Rate Based on the Binary GED-GARCH

    Institute of Scientific and Technical Information of China (English)

    陈守东; 高艳

    2012-01-01

    分别运用二元N-GARCH模型和二元GED-GARCH模型,对金融危机前后利率和汇率的波动溢出效应进行研究,通过自适应绝对偏差和自适应均方误差的平方根2种标准进行评价.研究认为,二元GED-GARCH预测效果更好,在金融危机前利率与汇率之间存在着由汇率到利率的溢出效应;在金融危机之后,利率与汇率具有双向的波动溢出效应.%We use binary N-GARCH and GED-GARCH models to analyze the Spillover Effects between Exchange Rate and Interest Rate before and after financial crisis respectively, and then valu-ate the two models by adaptive mean absolute deviation and adaptive root of mean square error criterion. As a result, we found out that the forecasting effect of binary GED-GARCH is better, and there is no Spillover Effects between Exchange Rate and Interest Rate before financial crisis, but there are two-way Spillover Effects between them after financial crisis.

  17. Bayesian Inference on Structure Change in GARCH Models Based on MCMC%基于MCMC的贝叶斯变结构金融时序GARCH模型研究

    Institute of Scientific and Technical Information of China (English)

    朱慧明; 曾惠芳; 郝立亚

    2011-01-01

    针对变结构GARCH模型没有解析形式的条件后验分布的问题。借助辅助变量把没有具体解析形式的后验分布转化为一系列完全条件分布,实现了变结构GARCH模型参数的贝叶斯估计。中国外汇市场波动性的实证研究,表明了辅助变量-Gibbs抽样有效的解决了贝叶斯变结构GARCH模型中的高维数值计算问题,并发现其波动持续性是由时间序列的状态转移引起的。%In the GARCH model with structural changes, simple Gibbs sampler is not feasible to simulate its posterior densities directly, because the analytical knowledge of conditional posterior densities is not available. After the introduction of auxiliary variables, the full conditionals can substitute for the awkward forms of conditional posterior densities to implement Gibbs iteration, which carried out the estimation of the GARCH model. The empirical analysis of the Chinese foreign exchange market illustrates that auxiliary sampler resolved the difficulties of the high dimension numerical integral in structure changing GARCH model effectively and the serious pseudo-persistence is caused by regime switching of the time series.

  18. 基于两重门限GARCH模型的短期负荷预测%Short term load forecasting based on double-threshold GARCH models

    Institute of Scientific and Technical Information of China (English)

    王玉荣; 万秋兰; 陈昊

    2011-01-01

    针对负荷时间序列的非线性和波动性特征,在研究负荷时间序列波动性门限特征的基础上,引入冲量门限的概念,提出了一种基于两重门限GARCH模型的短期负荷预测新方法.利用条件极大似然估计方法,估计了模型参数.同时,考虑到负荷时间序列波动的厚尾效应,将模型推广为服从非高斯分布假设下的情形,建立了2种基于厚尾假设的两重门限GARCH类负荷预测模型.利用所提出的混合信息冲击曲面,分析了不同性质的冲击和冲量对负荷时间序列波动性的影响.实际算例基于南京地区日用电量数据进行了短期负荷预测,验证了模型及方法的可行性和有效性.算例结果表明,服从广义误差分布的两重门限GARCH模型预测效果满意.%Considering the nonlinearity and volatility of load time series, threshold characteristics in load time series are analyzed. The concept of momentum threshold is employed and a novel double-threshold generalized auto-regressive conditional heteroskedasticity (DT-GARCH) model is proposed for short term load forecasting. By using the conditional maximum likelihood estimation (CMLE) , the parameters are estimated. In addition, with fat-tail effect in volatility, the proposed models with non-Gaussian distributions are highlighted and estimated. Furthermore, the hybrid news impact surface is proposed to help analyze the impact of different shocks and momentums to the load time series. In case study, short term load forecasting is carried out based on the historical daily power consumption data of Nanjing, which validates the feasibility and effectiveness of the proposed model. Numerical results indicate that the DT-GARCH model with generalized error distribution provides satisfying forecasting results.

  19. High molecular diversity of extraterrestrial organic matter in Murchison meteorite revealed 40 years after its fall.

    Science.gov (United States)

    Schmitt-Kopplin, Philippe; Gabelica, Zelimir; Gougeon, Régis D; Fekete, Agnes; Kanawati, Basem; Harir, Mourad; Gebefuegi, Istvan; Eckel, Gerhard; Hertkorn, Norbert

    2010-02-16

    Numerous descriptions of organic molecules present in the Murchison meteorite have improved our understanding of the early interstellar chemistry that operated at or just before the birth of our solar system. However, all molecular analyses were so far targeted toward selected classes of compounds with a particular emphasis on biologically active components in the context of prebiotic chemistry. Here we demonstrate that a nontargeted ultrahigh-resolution molecular analysis of the solvent-accessible organic fraction of Murchison extracted under mild conditions allows one to extend its indigenous chemical diversity to tens of thousands of different molecular compositions and likely millions of diverse structures. This molecular complexity, which provides hints on heteroatoms chronological assembly, suggests that the extraterrestrial chemodiversity is high compared to terrestrial relevant biological- and biogeochemical-driven chemical space.

  20. Polyphase-discrete Fourier transform spectrum analysis for the Search for Extraterrestrial Intelligence sky survey

    Science.gov (United States)

    Zimmerman, G. A.; Gulkis, S.

    1991-01-01

    The sensitivity of a matched filter-detection system to a finite-duration continuous wave (CW) tone is compared with the sensitivities of a windowed discrete Fourier transform (DFT) system and an ideal bandpass filter-bank system. These comparisons are made in the context of the NASA Search for Extraterrestrial Intelligence (SETI) microwave observing project (MOP) sky survey. A review of the theory of polyphase-DFT filter banks and its relationship to the well-known windowed-DFT process is presented. The polyphase-DFT system approximates the ideal bandpass filter bank by using as few as eight filter taps per polyphase branch. An improvement in sensitivity of approx. 3 dB over a windowed-DFT system can be obtained by using the polyphase-DFT approach. Sidelobe rejection of the polyphase-DFT system is vastly superior to the windowed-DFT system, thereby improving its performance in the presence of radio frequency interference (RFI).

  1. Extraterrestrial intelligence and human imagination SETI at the intersection of science, religion, and culture

    CERN Document Server

    Traphagan, John

    2015-01-01

    The search for extraterrestrial intelligence (SETI) represents one of the most significant crossroads at which the assumptions and methods of scientific inquiry come into direct contact with—and in many cases conflict with—those of religion. Indeed, at the core of SETI is the same question that motivates many interested in religion: What is the place of humanity in the universe? Both scientists involved with SETI (and in other areas) and those interested in and dedicated to some religious traditions are engaged in contemplating these types of questions, even if their respective approaches and answers differ significantly. This book explores this intersection with a focus on three core points: 1) the relationship between science and religion as it is expressed within the framework of SETI research, 2) the underlying assumptions, many of which are tacitly based upon cultural values common in American society, that have shaped the ways in which SETI researchers have conceptualized the nature of their endeavo...

  2. Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube Detector

    CERN Document Server

    Aartsen, M G; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Bechet, S; Tjus, J Becker; Becker, K -H; Benabderrahmane, M L; BenZvi, S; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Bertrand, D; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose, D; Böser, S; Botner, O; Brayeur, L; Bretz, H -P; Brown, A M; Bruijn, R; Brunner, J; Carson, M; Casey, J; Casier, M; Chirkin, D; Christov, A; Christy, B; Clark, K; Clevermann, F; Coenders, S; Cohen, S; Cowen, D F; Silva, A H Cruz; Danninger, M; Daughhetee, J; Davis, J C; Day, M; De Clercq, C; De Ridder, S; Desiati, P; de Vries, K D; de With, M; DeYoung, T; Díaz-Vélez, J C; Dunkman, M; Eagan, R; Eberhardt, B; Eichmann, B; Eisch, J; Ellsworth, R W; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grandmont, D T; Grant, D; Groß, A; Ha, C; Ismail, A Haj; Hallen, P; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Jagielski, K; Japaridze, G S; Jero, K; Jlelati, O; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kiryluk, J; Kläs, J; Klein, S R; Köhne, J -H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Krings, K; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Leute, J; Lünemann, J; Madsen, J; Maggi, G; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; O'Murchadha, A; Paul, L; Pepper, J A; Heros, C Pérez de los; Pfendner, C; Pieloth, D; Pinat, E; Posselt, J; Price, P B; Przybylski, G T; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Reimann, R; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Sestayo, Y; Seunarine, S; Shanidze, R; Sheremata, C; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tešić, G; Tilav, S; Toale, P A; Toscano, S; Unger, E; Usner, M; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Weaver, Ch; Wellons, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zoll, M

    2013-01-01

    We report on results of an all-sky search for high-energy neutrino events interacting within the IceCube neutrino detector conducted between May 2010 and May 2012. The search follows up on the previous detection of two PeV neutrino events, with improved sensitivity and extended energy coverage down to approximately 30 TeV. Twenty-six additional events were observed, substantially more than expected from atmospheric backgrounds. Combined, both searches reject a purely atmospheric origin for the twenty-eight events at the $4\\sigma$ level. These twenty-eight events, which include the highest energy neutrinos ever observed, have flavors, directions, and energies inconsistent with those expected from the atmospheric muon and neutrino backgrounds. These properties are, however, consistent with generic predictions for an additional component of extraterrestrial origin.

  3. Fermi's paradox, extraterrestrial life and the future of humanity: a Bayesian analysis

    CERN Document Server

    Verendel, Vilhelm

    2015-01-01

    The Great Filter interpretation of Fermi's great silence asserts that $Npq$ is not a very large number, where $N$ is the number of potentially life-supporting planets in the observable universe, $p$ is the probability that a randomly chosen such planet develops intelligent life to the level of present-day human civilization, and $q$ is the conditional probability that it then goes on to develop a technological supercivilization visible all over the observable universe. Evidence suggests that $N$ is huge, which implies that $pq$ is very small. Hanson (1998) and Bostrom (2008) have argued that the discovery of extraterrestrial life would point towards $p$ not being small and therefore a very small $q$, which can be seen as bad news for humanity's prospects of colonizing the universe. Here we investigate whether a Bayesian analysis supports their argument, and the answer turns out to depend critically on the choice of prior distribution.

  4. Measuring the effect of an astrobiology course on student optimism regarding extraterrestrial life

    Science.gov (United States)

    Morgan, David L.

    2017-07-01

    Students in an introductory undergraduate Astrobiology course were given a pre/post-test based on the Drake Equation in an attempt to measure changes in their perceptions regarding the prevalence of life in the Galaxy after taking the course. The results indicated that, after taking the course, the students were considerably more optimistic, by a 2 to 1 margin or more, about the prospect of habitable planets, the origin of life, and the evolution of intelligence in other planetary systems. The results suggest that, while it may not be the explicit goal of an astrobiology course to change student beliefs about the abundance or rarity of extraterrestrial life, such changes in opinion can and do occur.

  5. Internalizing Null Extraterrestrial "Signals": An Astrobiological App for a Technological Society

    CERN Document Server

    Chaisson, Eric J

    2014-01-01

    One of the beneficial outcomes of searching for life in the Universe is that it grants greater awareness of our own problems here on Earth. Lack of contact with alien beings to date might actually comprise a null "signal" pointing humankind toward a viable future. Astrobiology has surprising practical applications to human society; within the larger cosmological context of cosmic evolution, astrobiology clarifies the energetic essence of complex systems throughout the Universe, including technological intelligence that is intimately dependent on energy and likely will be for as long as it endures. The "message" contained within the "signal" with which today's society needs to cope is reasonably this: Only solar energy can power our civilization going forward without soiling the environment with increased heat yet robustly driving the economy with increased per capita energy usage. The null "signals" from extraterrestrials also offer a rational solution to the Fermi paradox as a principle of cosmic selection l...

  6. Fermi's paradox, extraterrestrial life and the future of humanity: a Bayesian analysis

    Science.gov (United States)

    Verendel, Vilhelm; Häggström, Olle

    2017-01-01

    The Great Filter interpretation of Fermi's great silence asserts that Npq is not a very large number, where N is the number of potentially life-supporting planets in the observable universe, p is the probability that a randomly chosen such planet develops intelligent life to the level of present-day human civilization, and q is the conditional probability that it then goes on to develop a technological supercivilization visible all over the observable universe. Evidence suggests that N is huge, which implies that pq is very small. Hanson (1998) and Bostrom (2008) have argued that the discovery of extraterrestrial life would point towards p not being small and therefore a very small q, which can be seen as bad news for humanity's prospects of colonizing the universe. Here we investigate whether a Bayesian analysis supports their argument, and the answer turns out to depend critically on the choice of prior distribution.

  7. The Murray Springs Clovis site, Pleistocene extinction, and the question of extraterrestrial impact.

    Science.gov (United States)

    Haynes, C Vance; Boerner, J; Domanik, K; Lauretta, D; Ballenger, J; Goreva, J

    2010-03-02

    Some of the evidence for the recent hypothesis of an extraterrestrial impact that caused late Pleistocene megafaunal extinctions [Firestone et al. (2007) Proc Natl Acad Sci USA 104:16016-16021] was based upon samples collected at Murray Springs, a Clovis archaeological site in southeastern Arizona. Here we describe sampling and analyses of magnetic separates from within, above, and below the lower Younger Dryas boundary (LYDB) black mat at Murray Springs, as well as radiation measurements from the LYDB at Murray Springs and two other well-stratified Clovis sites. The main magnetic fraction at Murray Springs is maghemite. Magnetic microspherules have terrestrial origins but also occur as cosmic dust particles. We failed to find iridium or radiation anomalies. The evidence for massive biomass burning at Murray Springs is addressed and found to be lacking. We could not substantiate some of the claims by Firestone and others, but our findings do not preclude a terminal Pleistocene cosmic event.

  8. The \\^G Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. I. Background and Justification

    CERN Document Server

    Wright, J T; Sigurðsson, S; Povich, M S

    2014-01-01

    We motivate the \\^G infrared search for extraterrestrial civilizations with large energy supplies. We discuss some philosophical difficulties of SETI, and how communication SETI circumvents them. We review "Dysonian SETI", the search for artifacts of alien civilizations, and find that it is highly complementary to traditional communication SETI; the two together might succeed where either one, alone, has not. We discuss the argument of Hart (1975) that spacefaring life in the Milky Way should be either galaxy-spanning or non-existent, and examine a portion of his argument that we dub the "monocultural fallacy". We discuss some rebuttals to Hart that invoke sustainability and predict long Galaxy colonization timescales. We find that the maximum Galaxy colonization timescale is actually much shorter than previous work has found ($< 10^9$ yr), and that many "sustainability" counter-arguments to Hart's thesis suffer from the monocultural fallacy. We extend Hart's argument to alien energy supplies, and argue th...

  9. A study of extraterrestrial antineutrino sources with the KamLAND detector

    Energy Technology Data Exchange (ETDEWEB)

    The KamLAND Collaboration; Gando, A.; Gando, Y.; Ichimura, K.; Ikeda, H.; Inoue, K.; Kibe, Y.; Kishimoto, Y.; Koga, M.; Minekawa, Y.; Mitsui, T.; Morikawa, T.; Nagai, N.; Nakajima, K.; Nakamura, K.; Narita, K.; Shimizu, I.; Shimizu, Y.; Shirai, J.; Suekane, F.; Suzuki, A.; Takahashi, H.; Takahashi, N.; Takemoto, Y.; Tamae, K.; Watanabe, H.; Xu, B. D.; Yabumoto, H.; Yoshida, H.; Yoshida, S.; Enomoto, S.; Kozlov, A.; Murayama, H.; Grant, C.; Keefer, G.; Piepke, A.; Banks, T. I.; Bloxham, T.; Detwiler, J. A.; Freedman, S. J.; Fujikawa, B. K.; Han, K.; Kadel, R.; O' Donnell, T.; Steiner, H. M.; Dwyer, D. A.; McKeown, R. D.; Zhang, C.; Berger, B. E.; Lane, C. E.; Maricic, J.; Miletic, T.; Batygov, M.; Learned, J. G.; Matsuno, S.; Sakai, M.; Horton-Smith, G. A.; Downum, K. E.; Gratta, G.; Efremenko, Y.; Kamyshkov, Y.; Perevozchikov, O.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Heeger, K. M.; Decowski, M. P.

    2011-05-18

    We present the results of a search for extraterrestrial electron antineutrinos ({bar {nu}}{sub e}'s) in the energy range 8.3 MeV < E{sub {bar {nu}}}{sub e} < 30.8 MeV using the KamLAND detector. In an exposure of 4.53 kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting an upper limit on the probability of {sup 8}B solar {nu}{sub e}'s converting into {bar {nu}}{sub e}'s at 5.3 x 10{sup -5} (90% C.L.). The present data also allows us to set more stringent limits on the diffuse supernova neutrino flux and on the annihilation rates for light dark matter particles.

  10. The nature of fossil bacteria: A guide to the search for extraterrestrial life

    Science.gov (United States)

    Westall, Frances

    1999-07-01

    In an attempt to establish reliable criteria for the identification of potential fossil life in extraterrestrial materials, the fossilizable characteristics of bacteria, namely, size, shape, cell wall texture, association, and colony formation, are described, and an overview is given of the ways in which fossil bacteria are preserved (as compressions in fine-grained sediments; preservation in amber; permineralized by silica; replacement by minerals such as silica, pyrite, Fe/Mn oxides, calcite, phosphate, and siderite; or as molds in minerals). The problem of confounding minerally replaced bacteria with non biological structures having a bacterial morphology is addressed. Examples of fossilized bacteria from the Early Archaean through to the Recent are used to illustrate the various modes of preservation and the morphology of fossil bacteria.

  11. Crystallographic Characterization of Extraterrestrial Materials by Energy-Scanning X-ray Diffraction

    Science.gov (United States)

    Hagiya, Kenji; Mikouchi, Takashi; Ohsumi, Kazumasa; Terada, Yasuko; Yagi, Naoto; Komatsu, Mutsumi; Yamaguchi, Shoki; Hirata, Arashi; Kurokawa, Ayaka; Zolensky, Michael E. (Principal Investigator)

    2016-01-01

    We have continued our long-term project using X-ray diffraction to characterize a wide range of extraterrestrial samples. The stationary sample method with polychromatic X-rays is advantageous because the irradiated area of the sample is always same and fixed, meaning that all diffraction spots occur from the same area of the sample, however, unit cell parameters cannot be directly obtained by this method though they are very important for identification of mineral and for determination of crystal structures. In order to obtain the cell parameters even in the case of the sample stationary method, we apply energy scanning of a micro-beam of monochromatic SR at SPring-8.

  12. A new empirical approach in the Search for Extraterrestrial Intelligence: Astrobiological nonlocality at the cosmological level

    CERN Document Server

    Thaheld, F H

    2006-01-01

    Over a period of several decades a concerted effort has been made to determine whether intelligent life exists outside of our solar system, known as the Search for Extraterrestrial Intelligence or SETI. This has been based primarily upon attempting to intercept possible radio transmissions at different frequencies with arrays of radio telescopes. In addition, astrophysical observations have also been undertaken to see if other worlds or solar systems exist with similar conditions such as ours, which might be conducive to life. And, numerous papers have been written exploring different possibilities for the existence of life or why we have not observed it as of yet, since none of these approaches have been successful. It may now be possible to explore this issue from another standpoint. Recent theoretical and experimental results in the field of biophysics appear to indicate the possibility of quantum entanglement and nonlocality at the biological level, between spatially separated pairs of human subjects and ...

  13. From Fossils to Astrobiology Records of Life on Earth and Search for Extraterrestrial Biosignatures

    CERN Document Server

    Seckbach, Joseph

    2008-01-01

    From Fossils to Astrobiology reviews developments in paleontology and geobiology that relate to the rapidly-developing field of Astrobiology, the study of life in the Universe. Many traditional areas of scientific study, including astronomy, chemistry and planetary science, contribute to Astrobiology, but the study of the record of life on planet Earth is critical in guiding investigations in the rest of the cosmos. In this varied book, expert scientists from 15 countries present peer-reviewed, stimulating reviews of paleontological and astrobiological studies. The overviews of established and emerging techniques for studying modern and ancient microorganisms on Earth and beyond, will be valuable guides to evaluating biosignatures which could be found in the extraterrestrial surface or subsurface within the Solar System and beyond. This volume also provides discussion on the controversial reports of "nanobacteria" in the Martian meteorite ALH84001. It is a unique volume among Astrobiology monographs in focusi...

  14. The Ĝ infrared search for extraterrestrial civilizations with large energy supplies. I. Background and justification

    Energy Technology Data Exchange (ETDEWEB)

    Wright, J. T.; Mullan, B.; Sigurdsson, S. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Povich, M. S. [Department of Physics and Astronomy, California State Polytechnic University, Pomona, 3801 West Temple Avenue, Pomona, CA 91768 (United States)

    2014-09-01

    We motivate the Ĝ infrared search for extraterrestrial civilizations with large energy supplies. We discuss some philosophical difficulties of the search for extraterrestrial intelligence (SETI), and how communication SETI circumvents them. We review 'Dysonian SETI', the search for artifacts of alien civilizations, and find that it is highly complementary to traditional communication SETI; the two together might succeed where either one alone has not. We discuss the argument of Hart that spacefaring life in the Milky Way should be either galaxy-spanning or non-existent, and examine a portion of his argument that we call the 'monocultural fallacy'. We discuss some rebuttals to Hart that invoke sustainability and predict long Galaxy colonization timescales. We find that the maximum Galaxy colonization timescale is actually much shorter than previous work has found (<10{sup 9} yr), and that many 'sustainability' counter-arguments to Hart's thesis suffer from the monocultural fallacy. We extend Hart's argument to alien energy supplies and argue that detectably large energy supplies can plausibly be expected to exist because life has the potential for exponential growth until checked by resources or other limitations, and intelligence implies the ability to overcome such limitations. As such, if Hart's thesis is correct, then searches for large alien civilizations in other galaxies may be fruitful; if it is incorrect, then searches for civilizations within the Milky Way are more likely to succeed than Hart argued. We review some past Dysonian SETI efforts and discuss the promise of new mid-infrared surveys, such as that of WISE.

  15. The Gˆ Mid-Infrared Search for Extraterrestrial Civilizations with Large Power Supplies: First Results

    Science.gov (United States)

    Povich, M. S.; Wright, J. T.; Griffith, R.; Sigurdsson, S.; Maldonado, J. T.; Mullan, B.

    2014-03-01

    We present initial results from the Glimpsing Heat from Alien Technologies ("G-HAT" or Gˆ), in which we use the WISE all-sky mid-infrared (MIR) Source Catalog to search for and place constraints on the abundance of extraterrestrial civilizations with large power supplies. A civilization consuming a significant fraction of the luminous power of their host star (Kardashev type II civilization or K2; Kardashev 1964) or galaxy (K3) and operating at a temperature similar to the equilibrium temperatures in or near stellar habitable zones will produce MIR excess emission in the form of waste heat. Searches for such MIR excesses from K2s have been performed in the past, notably by Carrigan (2009) using the IRAS source catalog. Taking advantage of the 103 improvement in sensitivity over IRAS provided by WISE, Gˆ has enabled the first systematic search for waste heat from galaxy-spanning K3 civilizations and will search for K2s throughout a significant fraction of the Milky Way's volume. We find that a galaxy-spanning (K III) civilization with an power supply of more than about one percent of its stellar luminosity will have detectable mid-infrared excess. We have produced a catalog of 32,000 WISE extended sources and visually reviewed the data and literature on the reddest 4000 of them, identifying several hundred candidates worthy of detailed observational follow-up. Mid-infrared spectra, far-infrared photometry, and radio emission from CO could be used to distinguish extraterrestrial mid-infrared radiation from dust. We will extend this analysis to WISE point sources to search for K2s.

  16. Extraterrestrial Amino Acids Identified in Metal-Rich CH and CB Carbonaceous Chondrites from Antarctica

    Science.gov (United States)

    Burton, Aaron S.; Elsila, Jamie E.; Hein, Jason E.; Glavin, Daniel P.; Dworkin, Jason P.

    2013-01-01

    Carbonaceous chondrites contain numerous indigenous organic compounds and could have been an important source of prebiotic compounds required for the origin of life on Earth or elsewhere. Extraterrestrial amino acids have been reported in five of the eight groups of carbonaceous chondrites and are most abundant in CI, CM, and CR chondritesbut are also present in the more thermally altered CV and CO chondrites. We report the abundance, distribution, and enantiomeric and isotopic compositions of simple primary amino acids in six metal-rich CH and CB carbonaceous chondrites that have not previously been investigated for amino acids: Allan Hills (ALH) 85085 (CH3), Pecora Escarpment(PCA) 91467 (CH3), Patuxent Range (PAT) 91546 (CH3), MacAlpine Hills (MAC) 02675(CBb), Miller Range (MIL) 05082 (CB), and Miller Range (MIL) 07411 (CB). Amino acid abundances and carbon isotopic values were obtained by using both liquid chromatography time-of-flight mass spectrometry and fluorescence, and gas chromatography isotope ratiomass spectrometry. The (delta D, delta C-13, delta N-15) ratios of multiple amino acids fall outside of the terrestrial range and support their extraterrestrial origin. Extracts of CH chondrites were found to be particularly rich in amino acids (1316 parts per million, ppm) while CB chondrite extracts had much lower abundances (0.22 ppm). The amino acid distributions of the CH and CB chondrites were distinct from the distributions observed in type 2 and 3 CM and CR chondrites and contained elevated levels of beta-, gamma-, and delta-amino acids compared to the corresponding alpha-amino acids, providing evidence that multiple amino acid formation mechanisms were important in CH and CB chondrites.

  17. Physical physics

    CERN Multimedia

    Schulman, Mark

    2006-01-01

    "Protons, electrons, positrons, quarks, gluons, muons, shmuons! I should have paid better attention to my high scholl physics teacher. If I had, maybe I could have understood even a fration of what Israeli particle physicist Giora Mikenberg was talking about when explaining his work on the world's largest science experiment." (2 pages)

  18. GaBoDS: The Garching-Bonn Deep Survey -- I. Anatomy of galaxy clusters in the background of NGC 300

    CERN Document Server

    Schirmer, M; Schneider, P; Pietrzynski, G; Gieren, W; Micol, A; Pierfederici, F; Schirmer, Mischa; Erben, Thomas; Schneider, Peter; Pietrzynski, Grzesiek; Gieren, Wolfgang; Micol, Alberto; Pierfederici, Francesco

    2003-01-01

    The Garching-Bonn Deep Survey (GaBoDS) is a virtual 12 square degree cosmic shear and cluster lensing survey, conducted with the WFI@2.2m MPG/ESO telescope at La Silla. It consists of shallow, medium and deep random fields taken in R-band in subarcsecond seeing conditions at high galactic latitude. A substantial amount of the data was taken from the ESO archive, by means of a dedicated ASTROVIRTEL program. In the present work we describe the main characteristics and scientific goals of GaBoDS. Our strategy for mining the ESO data archive is introduced, and we comment on the Wide Field Imager data reduction as well. In the second half of the paper we report on clusters of galaxies found in the background of NGC 300, a random archival field. We use weak gravitational lensing and the red cluster sequence method for the selection of these objects. Two of the clusters found were previously known and already confirmed by spectroscopy. Based on the available data we show that there is significant evidence for substr...

  19. GaBoDS: The Garching-Bonn Deep Survey. I. Anatomy of galaxy clusters in the background of NGC 300

    Science.gov (United States)

    Schirmer, M.; Erben, T.; Schneider, P.; Pietrzynski, G.; Gieren, W.; Carpano, S.; Micol, A.; Pierfederici, F.

    2003-09-01

    The Garching-Bonn Deep Survey (GaBoDS) is a virtual 12 square degree cosmic shear and cluster lensing survey, conducted with the WFI@2.2 m MPG/ESO telescope at La Silla. It consists of shallow, medium and deep random fields taken in R-band in subarcsecond seeing conditions at high galactic latitude. A substantial amount of the data was taken from the ESO archive, by means of a dedicated ASTROVIRTEL program. In the present work we describe the main characteristics and scientific goals of GaBoDS. Our strategy for mining the ESO data archive is introduced, and we comment on the Wide Field Imager data reduction as well. In the second half of the paper we report on clusters of galaxies found in the background of NGC 300, a random archival field. We use weak gravitational lensing and the red cluster sequence method for the selection of these objects. Two of the clusters found were previously known and already confirmed by spectroscopy. Based on the available data we show that there is significant evidence for substructure in one of the clusters, and an increasing fraction of blue galaxies towards larger cluster radii. Two other mass peaks detected by our weak lensing technique coincide with red clumps of galaxies. We estimate their redshifts and masses, and check for possible X-ray counterparts in deep XMM observations. Based on observations made with ESO Telescopes at the La Silla Observatory.

  20. Forecasting returns on a stock market using Artificial Neural Networks and GARCH family models: Evidence of stock market S&P 500

    Directory of Open Access Journals (Sweden)

    Nadhem Selmi

    2015-04-01

    Full Text Available In the area of financial stock market forecasting, many studies have focused on application of Artificial Neural Networks (ANNs. Due to its high rate of uncertainty and volatility, the stock markets returns forecasting by conventional methods became a difficult task. The ANNs is a relatively new and have been reported as good methods to predict financial stock market levels and can model flexible linear or non-linear relationship among variables. The aim of the study is to employ an ANN models to estimate and predict the dynamic volatility of the daily of S&P500 market returns. Results of ANN models will be compared with time series model using GARCH family models. The use of the novel model for conditional stock markets returns volatility can handle the vast amount of nonlinear data, simulate their relationship and give a moderate solution for the hard problem. The forecasts of stock index returns in the paper will be evaluated and compared, considering the MSE, RMSE and MAE forecasts statistic.

  1. Modelacion del Efecto del Día de la Semana para los Indices Accionarios de Colombia mediante un Modelo STAR GARCH.

    Directory of Open Access Journals (Sweden)

    David Mauricio Rivera Palacio

    2010-05-01

    Full Text Available En este trabajo se estudia el comportamiento de los retornos de los tres principales índices bursátiles de Colombia: el IBB de la Bolsa de Bogotá, el IBOMED de la Bolsa de Medellin, y el IGBC de Bolsa de Valores de Colombia. A través de un modelo STAR GARCH se identifican dos estados o regiones extremos; mientras en el primero los rendimientos de los índices son, en términos absolutos, bajos y los procesos son estacionarios, en el segundo se tienen grandes pérdidas o ganancias, donde los efectos de los choques son permanentes. Aunque en cada uno de los regímenes el efecto del día de la semana es diferente, los resultados indican que para los tres índices existe un efecto del día de la semana en la media, y un efecto del día en la varianza para la Bolsa de Bogotá y Bolsa de Valores de Colombia. Los resultados contradicen la hipótesis de un mercado de acciones efciente en información.

  2. The application of foreign exchange portfolio selection based on GARCH model%基于GARCH模型的外汇投资组合应用

    Institute of Scientific and Technical Information of China (English)

    雷震; 韦增欣

    2014-01-01

    This article uses time series model to analyze theforeign exchange rate of seven main cur-rencies, which contain EUR/USD、GBP/USD、USD/CHF、USD/JPY、AUD/USD、USD/CAD、NZD/USD . The GARCH model was used to forecast the rate of every currency, using the rate can calcu-late the profit expectation and usingresidual variance of every model to measure the risk. When mak-ing investment strategy, whether the leverage exists or not should be considered, then the “Mean-variance” model of Markowitz’s was used to get strategy for next day.%对于外汇市场主要7个货币对欧元/美元,英镑/美元,美元/瑞士法郎,美元/日元,澳元/美元,美元/加元,纽元/美元的汇率运用时间序列分析方法,分别运用GARCH模型对汇率进行建模预测,计算得到收益期望,以GARCH模型残差方差作为风险度量。对投资过程中有无杠杆,运用马可维茨的“均值-方差”模型进行投资决策,得到下一日的投资策略。

  3. The evolution of spillover effects between oil and stock markets across multi-scales using a wavelet-based GARCH-BEKK model

    Science.gov (United States)

    Liu, Xueyong; An, Haizhong; Huang, Shupei; Wen, Shaobo

    2017-01-01

    Aiming to investigate the evolution of mean and volatility spillovers between oil and stock markets in the time and frequency dimensions, we employed WTI crude oil prices, the S&P 500 (USA) index and the MICEX index (Russia) for the period Jan. 2003-Dec. 2014 as sample data. We first applied a wavelet-based GARCH-BEKK method to examine the spillover features in frequency dimension. To consider the evolution of spillover effects in time dimension at multiple-scales, we then divided the full sample period into three sub-periods, pre-crisis period, crisis period, and post-crisis period. The results indicate that spillover effects vary across wavelet scales in terms of strength and direction. By analysis the time-varying linkage, we found the different evolution features of spillover effects between the Oil-US stock market and Oil-Russia stock market. The spillover relationship between oil and US stock market is shifting to short-term while the spillover relationship between oil and Russia stock market is changing to all time scales. That result implies that the linkage between oil and US stock market is weakening in the long-term, and the linkage between oil and Russia stock market is getting close in all time scales. This may explain the phenomenon that the US stock index and the Russia stock index showed the opposite trend with the falling of oil price in the post-crisis period.

  4. Microbial Contamination of Allende and Murchison Carbonaceous Chondrites; Developing a Protocol for Life Detection in Extraterrestrial Materials Using Biotechnology

    Science.gov (United States)

    Steele, A.; Whitby, C.; Griffin, C.; Toporski, J. K. W.; Westall, F.; Saunders, J. R.; McKay, D. S.

    2001-01-01

    The arguments used to refute the McKay et al., (1996) hypothesis of possible Martian life in ALH84001 failed to use contamination of the meteorite as a source. This has worrying implications for our ability to detect terrestrial microbiota in meteorites and therefore any potential extraterrestrial biosignatures in both meteorites and possible returned samples. We report on imaging and microbial culturing of both Allende and Murchison carbonaceous chondrites and on the use of molecular biology techniques on a sample of Allende. Contaminating fungi and bacteria were observed (in the case of Murchison) and cultured from both meteorites. DNA was successfully extracted and subsequent PCR showed the presence of both bacterial and fungal DNA although no Archaea were detected. These results show that it is possible to use molecular biological techniques on very small quantities (300 mg) of extraterrestrial material.

  5. The \\^G Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. II. Framework, Strategy, and First Result

    CERN Document Server

    Wright, J T; Sigurðsson, S; Povich, M S; Mullan, B

    2014-01-01

    We describe the framework and strategy of the \\^G infrared search for extraterrestrial civilizations with large energy supplies, which will use the wide-field infrared surveys of WISE and Spitzer to search for these civilizations' waste heat. We develop a formalism for translating mid-infrared photometry into quantitative upper limits on extraterrestrial energy supplies. We discuss the likely sources of false positives, how dust can and will contaminate our search, and prospects for distinguishing dust from alien waste heat. We argue that galaxy-spanning civilizations may be easier to distinguish from natural sources than circumstellar civilizations (i.e., Dyson spheres), although Gaia will significantly improve our capability to identify the latter. We present a "zeroth order" null result of our search based on the WISE all-sky catalog: we show, for the first time, that Kardashev Type III civilizations (as Kardashev originally defined them) are very rare in the local universe. More sophisticated searches can...

  6. On the potential of seismic rotational motion measurements for extraterrestrial seismology

    Science.gov (United States)

    Schmelzbach, Cedric; Sollberger, David; Khan, Amir; Greenhalgh, Stewart; Van Renterghem, Cederic; Robertsson, Johan

    2017-04-01

    Classically, seismological recordings consist of measurements of translational ground motion only. However, in addition to three vector components of translation there are three components of rotation to consider, leading to six degrees of freedom. Of particular interest is thereby the fact that measuring rotational motion means isolating shear (S) waves. Recording the rotational motion requires dedicated rotational sensors. Alternatively, since the rotational motion is given by the curl of the vectorial displacements, the rotational motion around the two horizontal axes can be computed from the horizontal spatial gradients of vertical translational recordings if standard translational seismometers are placed in an areal array at the free surface. This follows from the zero stress free surface condition. Combining rotational and translational motion measurements opens up new ways of analyzing seismic data, such as facilitating much improved arrival identification and wavefield separation (e.g., P-/S-wave separation), and local slowness (arrival direction and velocity) determination. Such combined measurements maximize the seismic information content that a single six-component station or a small station array can provide, and are of particular interest for sparse or single-station measurements such as in extraterrestrial seismology. We demonstrate the value of the analysis of combined translational and rotational recordings by re-evaluating data from the Apollo 17 lunar seismic profiling experiment (LSPE). The LSPE setup consisted of four vertical-component geophones arranged in a star-like geometry. This areal receiver layout enables computing the horizontal spatial gradients by spatial finite differencing of the vertical-component data for two perpendicular directions and, hence, the estimation of rotational motion around two horizontal axes. Specifically, the recorded seismic waveform data originated from eight explosive packages as well as from continuously

  7. PREFACE: 31st European Physical Society Conference on Plasma Physics

    Science.gov (United States)

    Dendy, Richard

    2004-12-01

    This special issue of Plasma Physics and Controlled Fusion comprises refereed papers contributed by invited speakers at the 31st European Physical Society Conference on Plasma Physics. The conference was jointly hosted by the Rutherford Appleton Laboratory, by the EURATOM/UKAEA Fusion Association and by Imperial College London, where it took place from 28 June to 2 July 2004. The overall agenda for this conference was set by the Board of the Plasma Physics Division of the European Physical Society, chaired by Friedrich Wagner (MPIPP, Garching) and his successor Jo Lister (CRPP, Lausanne). It built on developments in recent years, by further increasing the scientific diversity of the conference programme, whilst maintaining its depth and quality. A correspondingly diverse Programme Committee was set up, whose members are listed below. The final task of the Programme Committee has been the preparation of this special issue. In carrying out this work, as in preparing the scientific programme of the conference, the Programme Committee formed specialist subcommittees representing the different fields of plasma science. The chairmen of these subcommittees, in particular, accepted a very heavy workload on behalf of their respective research communities. It is a great pleasure to take this opportunity to thank: Emilia R Solano (CIEMAT, Madrid), magnetic confinement fusion; Jürgen Meyer-ter-Vehn (MPQ, Garching), laser-plasma interaction and beam plasma physics; and Jean-Luc Dorier (CRPP, Lausanne), dusty plasmas. The relatively few papers in astrophysical and basic plasma physics were co-ordinated by a small subcommittee which I led. Together with Peter Norreys (RAL, Chilton), we five constitute the editorial team for this special issue. The extensive refereeing load, compressed into a short time interval, was borne by the Programme Committee members and by many other experts, to whom this special issue owes much. We are also grateful to the Local Organizing Committee

  8. Investigations in space-related molecular biology. [cryo-electron microscopic and diffraction studies on terrestrial and extraterrestrial specimens

    Science.gov (United States)

    Fernandez-Moran, H.; Pritzker, A. N.

    1974-01-01

    Improved instrumentation and preparation techniques for high resolution, high voltage cryo-electron microscopic and diffraction studies on terrestrial and extraterrestrial specimens are reported. Computer correlated ultrastructural and biochemical work on hydrated and dried cell membranes and related biological systems provided information on membrane organization, ice crystal formation and ordered water, RNA virus linked to cancer, lunar rock samples, and organometallic superconducting compounds. Apollo 11, 12, 14, and 15 specimens were analyzed

  9. The Berkeley piggyback SETI program - SERENDIP II. [Search for Extraterrestrial Radio Emission from Nearby Developed Intelligent Populations

    Science.gov (United States)

    Bowyer, S.; Werthimer, D.; Lindsay, V.

    1988-01-01

    The SERENDIP (Search for Extraterrestrial Radio Emission from Nearby Developed Intelligent Populations) II system is currently operating at NRAO's 300-ft telescope in Greenbank, WV. The paper reports on the characteristics of this system in combination with this telescope, as well as elements of an off-line analysis program which are intended to identify signals of special interest. The sensitivity and relative probability of acquisition are evaluated.

  10. Widening Perspectives: The Intellectual and Social Benefits of Astrobiology (Regardless of Whether Extraterrestrial Life is Discovered or Not)

    OpenAIRE

    Crawford, Ian A.

    2017-01-01

    Astrobiology is usually defined as the study of the origin, evolution, distribution, and future of life in the universe. As such it is inherently interdisciplinary and cannot help but engender a worldview infused by cosmic and evolutionary perspectives. Both these attributes of the study of astrobiology are, and will increasingly prove to be, beneficial to society regardless of whether extraterrestrial life is discovered or not.

  11. The need for operating guidelines and a decision making framework applicable to the discovery of non-intelligent extraterrestrial life

    Science.gov (United States)

    Race, Margaret S.; Randolph, Richard O.

    While formal principles have been adopted for the eventuality of detecting intelligent life in our galaxy (SETI Principles), no such guidelines exist for the discovery of non-intelligent extraterrestrial life within the solar system. Current scientifically based planetary protection policies for solar system exploration address how to undertake exploration, but do not provide clear guidance on what to do if and when life is detected. Considering that martian life could be detected under several different robotic and human exploration scenarios in the coming decades, it is appropriate to anticipate how detection of non-intelligent, microbial life could impact future exploration missions and activities, especially on Mars. This paper discusses a proposed set of interim guidelines based loosely on the SETI Principles and addresses issues extending from the time of discovery through future handling and treatment of extraterrestrial life on Mars or elsewhere. Based on an analysis of both scientific and ethical considerations, there is a clear need for developing operating protocols applicable at the time of discovery and a decision making framework that anticipates future missions and activities, both robotic and human. There is growing scientific confidence that the discovery of extraterrestrial life in some form is nearly inevitable. If and when life is discovered beyond Earth, non-scientific dimensions may strongly influence decisions about the nature and scope of future missions and activities. It is appropriate to encourage international discussion and consideration of the issues prior to an event of such historical significance.

  12. 长记忆ARFIMA-GARCH模型的状态空间模型估计%State Space Estimation for Long Memory ARFIMA-GARCH Models

    Institute of Scientific and Technical Information of China (English)

    王立洪; 顾承祖

    2011-01-01

    本文考虑了ARFIMA-GARCH类模型的状态空间表示.ARFIMA-GARCH这类模型结合了长记忆时间序列和条件异方差过程.虽然ARFIMA-GARCH模型的状态空间表示是无穷维的,但是基于这种表示法的精确极大似然估计可以在样本长度的迭代计算中得到.本文提出了基于模型的截断的自回归展开式的似然函数近似估计,进而得到了模型参数的拟似然估计.利用状态空间表示的便利,本文的估计方法被应用到了缺失数据的情形.最后,我们还将本文的方法应用于模拟计算(缺失数据和非缺失数据)和实际数据分析.%This paper considers the state space representation for the ARFIMA-GARCH model,which combines both the long memory time series and the conditional heteroscedastic processes.Although this state space representation is infinite dimensional,an exact maximum likelihood (ML) estimator based on this kind of representation can be computed in a finite number of iterations.Quasi ML estimators based on the autoregressive approximation for the likelihood function are proposed.Due to the facility of the state space representation,these estimation approaches can be easily applied to the missing data case.Simulation results of both the non-missing data case and the missing data case are reported.A real data example from stock market illustrates the proposed method.

  13. Unknown caller: can we effectively manage the announcement of discovery of extraterrestrial life?

    Science.gov (United States)

    Gartrelle, Gordon M.

    2015-10-01

    The definitive discovery of another form of life from beyond Earth will answer one of our most fundamental questions: Are we alone in the Universe? This announcement will be the most significant in history. It will have impact on every facet of our lives and affect everyone on Earth. Ensuring the announcement is handled properly represents an opportunity to unify government, industrial, and scientific resources to work together on a global scale issue. The purpose of the present paper is to understand whether we have the overall strategy, management structures and process disciplines in place on a global scale to handle an announcement of this magnitude. The research methodology included review and analysis of peer-reviewed work on the topic, publications from appropriate scientific and policy organizations, and public statements from several acknowledged experts in the field of astrobiology and extraterrestrial communications. The 1996 case of the announcement of possible life from Martian meteorite ALH84001 was also analysed. The findings of the paper are multiple deficiencies exist in the ability to manage this problem globally in an integrated fashion across borders, institutional boundaries, and through the media. High-level recommendations are offered to address major identified gaps.

  14. Curating NASA's future extraterrestrial sample collections: How do we achieve maximum proficiency?

    Science.gov (United States)

    McCubbin, Francis; Evans, Cynthia; Allton, Judith; Fries, Marc; Righter, Kevin; Zolensky, Michael; Zeigler, Ryan

    2016-07-01

    Introduction: The Astromaterials Acquisition and Curation Office (henceforth referred to herein as NASA Curation Office) at NASA Johnson Space Center (JSC) is responsible for curating all of NASA's extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10E "Curation of Extraterrestrial Materials", JSC is charged with "The curation of all extraterrestrial material under NASA control, including future NASA missions." The Directive goes on to define Curation as including "…documentation, preservation, preparation, and distribution of samples for research, education, and public outreach." Here we describe some of the ongoing efforts to ensure that the future activities of the NASA Curation Office are working to-wards a state of maximum proficiency. Founding Principle: Curatorial activities began at JSC (Manned Spacecraft Center before 1973) as soon as design and construction planning for the Lunar Receiving Laboratory (LRL) began in 1964 [1], not with the return of the Apollo samples in 1969, nor with the completion of the LRL in 1967. This practice has since proven that curation begins as soon as a sample return mission is conceived, and this founding principle continues to return dividends today [e.g., 2]. The Next Decade: Part of the curation process is planning for the future, and we refer to these planning efforts as "advanced curation" [3]. Advanced Curation is tasked with developing procedures, technology, and data sets necessary for curating new types of collections as envisioned by NASA exploration goals. We are (and have been) planning for future curation, including cold curation, extended curation of ices and volatiles, curation of samples with special chemical considerations such as perchlorate-rich samples, curation of organically- and biologically-sensitive samples, and the use of minimally invasive analytical techniques (e.g., micro-CT, [4]) to characterize samples. These efforts will be useful for Mars Sample Return

  15. An Atlas of extraterrestrial particles collected with NASA U-2 aircraft, 1974 - 1976

    Science.gov (United States)

    Brownlee, D. E.; Tomandl, D.; Blanchard, M. B.; Ferry, G. V.; Kyte, F.

    1976-01-01

    Extraterrestrial particles collected during U-2 flights in the stratosphere were divided into four groups: chondritic, iron-sulfur--nickel, mafic silicates, and others. The chondritic aggregates are typically composed of Fe, Mg, Si, C, S, Ca, and Ni. Detectable levels of He-4 implanted from the solar wind occur in some. Olivine, spinel, and possibly pyrrhotite and a hydrated layered-lattice silicate were identified. The chondritic ablation particles contain no sulfur and appear to have been melted. Magnetite, olivine, and pyroxene were identified. The iron-sulfur-nickel type particles resemble meteoritic iron sulfide with a small amount of nickel, and contain magnetite and troilite. The mafic silicate type particles are iron magnesium silicate grains with clumps of chondritic aggregate particles adhering to their surfaces. Olivine and possibly pyrrhotite and pyroxene were identified. Most of the iron-nickel type particles are spherules and include taenite and wustite. The other type particles include nickel-iron mounds on spheroidal glassy-like grains having chondritic-like elemental abundances.

  16. Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites

    Science.gov (United States)

    Vollmer, Christian; Kepaptsoglou, Demie; Leitner, Jan; Busemann, Henner; Spring, Nicole H.; Ramasse, Quentin M.; Hoppe, Peter; Nittler, Larry R.

    2014-01-01

    Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight 15N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C–O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C–O bonding environments and nanoglobular organics with dominant aromatic and C–N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid. PMID:25288736

  17. An Opportunistic Search for Extraterrestrial Intelligence (SETI) with the Murchison Widefield Array

    Science.gov (United States)

    Tingay, S. J.; Tremblay, C.; Walsh, A.; Urquhart, R.

    2016-08-01

    A spectral line image cube generated from 115 minutes of MWA data that covers a field of view of 400 sq, deg. around the Galactic Center is used to perform the first Search for ExtraTerrestrial Intelligence (SETI) with the Murchison Widefield Array (MWA). Our work constitutes the first modern SETI experiment at low radio frequencies, here between 103 and 133 MHz, paving the way for large-scale searches with the MWA and, in the future, the low-frequency Square Kilometre Array. Limits of a few hundred mJy beam-1 for narrowband emission (10 kHz) are derived from our data, across our 400 sq. deg. field of view. Within this field, 45 exoplanets in 38 planetary systems are known. We extract spectra at the locations of these systems from our image cube to place limits on the presence of narrow line emission from these systems. We then derive minimum isotropic transmitter powers for these exoplanets; a small handful of the closest objects (10 s of pc) yield our best limits of order 1014 W (Equivalent Isotropic Radiated Power). These limits lie above the highest power directional transmitters near these frequencies currently operational on Earth. A SETI experiment with the MWA covering the full accessible sky and its full frequency range would require approximately one month of observing time. The MWA frequency range, its southern hemisphere location on an extraordinarily radio quiet site, its very large field of view, and its high sensitivity make it a unique facility for SETI.

  18. Understanding Prebiotic Chemistry Through the Analysis of Extraterrestrial Amino Acids and Nucleobases in Meteorites

    Science.gov (United States)

    Burton, Aaron S.; Stern, Jennifer C.; Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

    2012-01-01

    The discoveries of amino acids of extraterrestrial origin in many meteorites over the last 50 years have revolutionized the Astrobiology field. A variety of non-terrestrial amino acids similar to those found in life on Earth have been detected in meteorites. A few amino acids have even been found with chiral excesses, suggesting that meteorites could have contributed to the origin of homochirality in life on Earth. In addition to amino acids, which have been productively studied for years, sugar-like molecules, activated phosphates, and nucleobases have also been determined to be indigenous to numerous meteorites. Because these molecules are essential for life as we know it, and meteorites have been delivering them to the Earth since accretion, it is plausible that the origines) of life on Earth were aided by extrataterrestrially-synthesized molecules. Understanding the origins of life on Earth guides our search for life elsewhere, helping to answer the question of whether biology is unique to Earth. This tutorial focuses on meteoritic amino acids and nucleobases, exploring modern analytical methods and possible formation mechanisms. We will also discuss the unique window that meteorites provide into the chemistry that preceded life on Earth, a chemical record we do not have access to on Earth due to geologic recycling of rocks and the pervasiveness of biology across the planet. Finally. we will address the future of meteorite research, including asteroid sample return missions.

  19. Microbial fuel cells applied to the metabolically based detection of extraterrestrial life.

    Science.gov (United States)

    Abrevaya, Ximena C; Mauas, Pablo J D; Cortón, Eduardo

    2010-12-01

    Since the 1970s, when the Viking spacecrafts carried out experiments to detect microbial metabolism on the surface of Mars, the search for nonspecific methods to detect life in situ has been one of the goals of astrobiology. It is usually required that a methodology detect life independently from its composition or form and that the chosen biological signature point to a feature common to all living systems, such as the presence of metabolism. In this paper, we evaluate the use of microbial fuel cells (MFCs) for the detection of microbial life in situ. MFCs are electrochemical devices originally developed as power electrical sources and can be described as fuel cells in which the anode is submerged in a medium that contains microorganisms. These microorganisms, as part of their metabolic process, oxidize organic material, releasing electrons that contribute to the electric current, which is therefore proportional to metabolic and other redox processes. We show that power and current density values measured in MFCs that use microorganism cultures or soil samples in the anode are much larger than those obtained with a medium free of microorganisms or sterilized soil samples, respectively. In particular, we found that this is true for extremophiles, which have been proposed as potential inhabitants of extraterrestrial environments. Therefore, our results show that MFCs have the potential to be used for in situ detection of microbial life.

  20. An Opportunistic Search for ExtraTerrestrial Intelligence (SETI) with the Murchison Widefield Array

    CERN Document Server

    Tingay, S J; Walsh, A; Urquhart, R

    2016-01-01

    A spectral line image cube generated from 115 minutes of MWA data that covers a field of view of 400 sq. deg. around the Galactic Centre is used to perform the first Search for ExtraTerrestrial Intelligence (SETI) with the Murchison Widefield Array. Our work constitutes the first modern SETI experiment at low radio frequencies, here between 103 and 133 MHz, paving the way for large-scale searches with the MWA and, in the future, the low frequency Square Kilometre Array. Limits of a few hundred mJy/beam for narrow band emission (10 kHz) are derived from our data, across our 400 sq. deg. field of view. Within this field, 45 exoplanets in 38 planetary systems are known. We extract spectra at the locations of these systems from our image cube, to place limits on the presence of narrow line emission from these systems. We then derive minimum isotropic transmitter powers for these exoplanets; a small handful of the closest objects (10s of pc) yield our best limits of order $10^{14}$ W (Equivalent Isotropic Radiated...

  1. Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites.

    Science.gov (United States)

    Vollmer, Christian; Kepaptsoglou, Demie; Leitner, Jan; Busemann, Henner; Spring, Nicole H; Ramasse, Quentin M; Hoppe, Peter; Nittler, Larry R

    2014-10-28

    Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight (15)N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C-O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C-O bonding environments and nanoglobular organics with dominant aromatic and C-N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid.

  2. Discovery of extra-terrestrial life: assessment by scales of its importance and associated risks.

    Science.gov (United States)

    Almár, Iván; Race, Margaret S

    2011-02-13

    The Rio Scale accepted by the SETI Committee of the International Academy of Astronautics in 2002 is intended for use in evaluating the impact on society of any announcement regarding the discovery of evidence of extra-terrestrial (ET) intelligence. The Rio Scale is mathematically defined using three parameters (class of phenomenon, type of discovery and distance) and a δ factor, the assumed credibility of a claim. This paper proposes a new scale applicable to announcements alleging evidence of ET life within or outside our Solar System. The London Scale for astrobiology has mathematical structure and logic similar to the Rio Scale, and uses four parameters (life form, nature of phenomenon, type of discovery and distance) as well as a credibility factor δ to calculate a London Scale index (LSI) with values ranging from 0 to 10. The level of risk or biohazard associated with a purported discovery is evaluated independently of the LSI value and may be ranked in four categories. The combined information is intended to provide a scalar assessment of the scientific importance, validity and potential risks associated with putative evidence of ET life discovered on Earth, on nearby bodies in the Solar System or in our Galaxy.

  3. Extremophilic iron-reducing bacteria: Their implications for possible life in extraterrestrial environments

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, J.; Liu, S.V.; Zhang, C.; Palumbo, A.V.; Phelps, T.J.

    1998-06-01

    Iron reduction is believed to be an early form of respiration and iron-reducing bacteria might have evolved very early on Earth. To support this hypothesis, the authors began to search for both thermophilic and psychrophilic iron-reducing bacteria because iron-reducing capacity may be a widely distributed trait if ancestral microorganisms include extremophilic iron-reducing bacteria. To date, they have obtained thermophilic Fe(III)-reducing and magnetite-forming enrichment cultures from geologically and hydrologically isolated, millions of years-old deep terrestrial subsurface samples. Three dominant bacteria were identified based on 16S ribosomal RNA gene sequences. Phylogenetical analysis indicated that these bacteria were closely related to Thermoanaerobacter ethanoliticus. Two pure thermophilic iron-reducing bacteria have been isolated and characterized from these enrichments, they also are able to degrade cellulose and xylan. Geological evidence indicated that these bacteria were separated from modern organisms for about 200 million years, and they are the oldest isolated bacteria available now. Evolutionary sequence analysis showed that the 16S rRNA genes evolved extremely slowly in these bacteria. In addition, the authors have obtained about 30 psychrophilic iron-reducing bacteria in samples from Siberia and Alaska permafrost soils, Pacific marine sediments and Hawaii deep sea water. These bacteria were also able to reduce other heavy metals. The isolation of both thermophilic and psychrophilic iron-reducing bacteria from surface and subsurface environments has significant implications for microbial evolution and for studying the origin of life in extraterrestrial environments.

  4. Evidence of the Price Discovery and Volatility Spillover of the CSI 300 Stock Index Futures Based on the BEEK-GARCH Model%沪深300股指期货的价格发现能力及波动溢出效应研究--基于BEEK-GARCH 模型的证据

    Institute of Scientific and Technical Information of China (English)

    陶启智; 李亮; 郭姝辛

    2015-01-01

    以沪深300股指期货自推出至今的1分钟数据作为研究样本,使用BEEK‐GARCH模型量化沪深300股指期货和现货市场的价格发现能力及波动溢出效应。研究发现,我国期货市场成立初期并未发挥其价格发现功能,这一现象随着市场成熟度增加而逐渐改善,期货市场在价格发现过程中占主要地位。通过GARCH 模型对收益率调整过程进行估计,发现市场之间存在双向波动溢出效应:短期内表现出均值回归;长期来看,误差修正项系数显著异于0,符合调整的负反馈性质,价格偏差会被纠正从而达到长期均衡。%With the 1 minute interval data up to the present time of the CSI 300 stock index futures as the samples ,this paper quantitatively studies the price discovery and volatility spillover of the CSI 300 stock index futures and spot markets ,using the BEEK‐GARCH model .The impulse response function and vari‐ance decomposition are used to imply the price discovery ,w hich show s that the future market plays a more important role .A vector error correction model is built to describe the dynamic adjustment of the futures and spot price of stock indexes .The result shows that there exists a two‐way granger causal relationship between the futures and the spots ,as well as a volatility spillover effect .The regression will return to the mean in the short run and satisfies the negative feedback of the correction that the existence of arbitrage will adjust the bias to the equilibrium in the long run .

  5. Laser Physics and Laser Techniques

    Science.gov (United States)

    1989-06-01

    Other types of laser-assisted materials process- Planck Institute for Quantum Optics. Garching . West ing and machining, including laser cutting, welding...detectors with microstructured electrodes, 134[ G. N. Maracas. G. L. Harrs, C. A. Lee. and R. A. McFarlane. Opt. Le’tt., vol. 7, pp. 575-577, Dcc . 1982...A. E. Siegman Max-Planck Institut f’r Quantenoptik, D-8046 Garching , West Germany and E. L. Ginzton Laboratory, Stanford University, Stanford

  6. Evidence for a Massive Extraterrestrial Airburst over North America 12.9 ka Ago

    Science.gov (United States)

    Firestone, R. B.; West, A.; Revay, Z.; Belgya, T.; Smith, A.; Que Hee, S. S.

    2007-05-01

    A carbon-rich black layer commonly referred to as a black mat, with a basal age of approximately 12.9 ka, has been identified at over 50 sites across North America1. The age of the base of the black mat coincides with the abrupt onset of Younger Dryas cooling and megafaunal extinctions in North America. In situ bones of extinct mammals, including mammoths, mastodons, ground sloths, horses, camels, many smaller mammals and birds, and Clovis tool assemblages occur below the black mat but not within or above it. In this paper, we provide evidence for an ejecta layer at the base of the black mat from an extraterrestrial impact event 12.9 ka ago. We have investigated nine terminal Clovis-age sites in North America and a comparable site in Lommel, Belgium that are all marked by a thin, discrete layer containing varying peak abundances of (1) magnetic grains/microspherules containing iridium concentrations up to 117 ppb, (2) charcoal, (3) soot, (4) vesicular carbon spherules, (5) glass-like carbon, and (6) fullerenes enriched in 3He. This layer also extends throughout the rims of at least fifteen Carolina Bays, unique, elliptical, oriented lakes and wetlands scattered across the Atlantic Coastal Plain whose major axes point towards the Great Lakes and Canada. Microspherules, highly enriched in titanium, were found only in or near the YD boundary (YDB) layer with greatest deposition rates (35 per cm2) occurring near the Great Lakes. Magnetic grains also peak in the YDB with maximum deposition near the Great Lakes (30 mg/cm2). Magnetic grains near the Great Lakes are enriched in magnetite (4 mg/cm2) and silicates (23 mg/cm2) but contain less ilmenite/rutile (1 mg/cm2) than distant sites where ilmentite/rutile deposition ranges up to 18 mg/cm2. Analysis of the ilmenite/rutile-rich magnetic grains and microspherules indicates that they contain considerable water, up to 28 at.% hydrogen, and have TIO2/FeO, TIO2/Zr, Al2O3/FeO+MgO, CaO/Al2O3, REE/chondrite, K/Th, FeO/MnO ratios

  7. Pieces of Other Worlds - Enhance YSS Education and Public Outreach Events with Extraterrestrial Samples

    Science.gov (United States)

    Allen, C.

    2010-12-01

    During the Year of the Solar System spacecraft will encounter two comets; orbit the asteroid Vesta, continue to explore Mars with rovers, and launch robotic explorers to the Moon and Mars. We have pieces of all these worlds in our laboratories. Extensive information about these unique materials, as well as actual lunar samples and meteorites, is available for display and education. The Johnson Space Center (JSC) curates NASA's extraterrestrial samples to support research, education, and public outreach. At the current time JSC curates five types of extraterrestrial samples: Moon rocks and soils collected by the Apollo astronauts Meteorites collected on US expeditions to Antarctica (including rocks from the Moon, Mars, and many asteroids including Vesta) “Cosmic dust” (asteroid and comet particles) collected by high-altitude aircraft Solar wind atoms collected by the Genesis spacecraft Comet and interstellar dust particles collected by the Stardust spacecraft These rocks, soils, dust particles, and atoms continue to be studied intensively by scientists around the world. Descriptions of the samples, research results, thousands of photographs, and information on how to request research samples are on the JSC Curation website: http://curator.jsc.nasa.gov/ NASA is eager for scientists and the public to have access to these exciting samples through our various loan procedures. NASA provides a limited number of Moon rock samples for either short-term or long-term displays at museums, planetariums, expositions, and professional events that are open to the public. The JSC Public Affairs Office handles requests for such display samples. Requestors should apply in writing to Mr. Louis Parker, JSC Exhibits Manager. He will advise successful applicants regarding provisions for receipt, display, and return of the samples. All loans will be preceded by a signed loan agreement executed between NASA and the requestor's organization. Email address: louis.a.parker@nasa.gov Sets

  8. Extra-terrestrial igneous granites and related rocks: A review of their occurrence and petrogenesis

    Science.gov (United States)

    Bonin, Bernard

    2012-11-01

    The telluric planets and the asteroid belt display the same internal structure with a metallic inner core and a silicate outer shell. Experimental data and petrological evidence in silicate systems show that granite can be produced by extreme igneous differentiation through various types of igneous processes. On Moon, 4.4-3.9 Ga granite clasts display dry mineral assemblages. They correspond to at least 8 discrete intrusive events. Large K/Ca enrichment and low REE abundances in granite relative to KREEP are consistent with silicate liquid immiscibility, a process observed in melt inclusions within olivine of lunar basalts and in lunar meteorites. Steep-sided domes identified by remote sensing can represent intrusive or extrusive felsic formations. On Mars, black-and-white rhythmic layers observed on the Tharsis rise along the flanks of the peripheral scarps of the Tharsis Montes giant volcanoes suggest the possible eruption of felsic pyroclastites. Though no true granites were found so far in the Martian SNC meteorites, felsic glasses and mesostases were identified and a component close to terrestrial continental (granitic) crust is inferred from trace element and isotope systematics. Venus has suffered extensive volcanic resurfacing, whereas folded and faulted areas resemble terrestrial continents. Near large shield volcanoes, with dominant basaltic compositions, steep-sided domes have been interpreted as non-degassed silicic extrusions. The hypothesis of a granitic component is "tantalising". Extra-terrestrial granite is frequently found as clasts and mesostases in asteroidal meteorites. Porphyritic textures, with alkali feldspar crystals up to several centimetres in size, were observed in silicate enclaves within iron meteorites. In the chondrite clan, polymict breccias can contain granitic clasts, whose provenance is debated. One clast from the Adzhi-Bogdo meteorite yields a 4.53 ± 0.03 Ga Pb-Pb age, making it the oldest known granite in the solar system. The

  9. Venusians: the Planet Venus in the 18th-Century Extraterrestrial Life Debate

    Science.gov (United States)

    Duner, David

    2013-05-01

    In the seventeenth and eighteenth centuries it became possible to believe in the existence of life on other planets on scientific grounds. Once the Earth was no longer the center of the universe according to Copernicus, once Galileo had aimed his telescope at the Moon and found it a rough globe with mountains and seas, the assumption of life on other planets became much less far-fetched. In general there were no actual differences between Earth and Venus, since both planets orbited the Sun, were of similar size, and possessed mountains and an atmosphere. If there is life on Earth, one may ponder why it could not also exist on Venus. In the extraterrestrial life debate of the seventeenth and eighteenth centuries, the Moon, our closest celestial body, was the prime candidate for life on other worlds, although a number of scientists and scholars also speculated about life on Venus and on other planets, both within our solar system and beyond its frontiers. This chapter discusses the arguments for life on Venus and those scientific findings that were used to support them, which were based in particular on assumptions and claims that both mountains and an atmosphere had been found on Venus. The transits of Venus in the 1760s became especially important for the notion that life could thrive on Venus. Here, I detect two significant cognitive processes that were at work in the search for life on Venus, i.e., analogical reasoning and epistemic perception, while analogies and interpretations of sensory impressions based on prior knowledge played an important role in astrobiological theories.

  10. The high-resolution extraterrestrial solar spectrum (QASUMEFTS determined from ground-based solar irradiance measurements

    Directory of Open Access Journals (Sweden)

    J. Gröbner

    2017-09-01

    Full Text Available A high-resolution extraterrestrial solar spectrum has been determined from ground-based measurements of direct solar spectral irradiance (SSI over the wavelength range from 300 to 500 nm using the Langley-plot technique. The measurements were obtained at the Izaña Atmospheric Research Centre from the Agencia Estatal de Meteorología, Tenerife, Spain, during the period 12 to 24 September 2016. This solar spectrum (QASUMEFTS was combined from medium-resolution (bandpass of 0.86 nm measurements of the QASUME (Quality Assurance of Spectral Ultraviolet Measurements in Europe spectroradiometer in the wavelength range from 300 to 500 nm and high-resolution measurements (0.025 nm from a Fourier transform spectroradiometer (FTS over the wavelength range from 305 to 380 nm. The Kitt Peak solar flux atlas was used to extend this high-resolution solar spectrum to 500 nm. The expanded uncertainties of this solar spectrum are 2 % between 310 and 500 nm and 4 % at 300 nm. The comparison of this solar spectrum with solar spectra measured in space (top of the atmosphere gave very good agreements in some cases, while in some other cases discrepancies of up to 5 % were observed. The QASUMEFTS solar spectrum represents a benchmark dataset with uncertainties lower than anything previously published. The metrological traceability of the measurements to the International System of Units (SI is assured by an unbroken chain of calibrations leading to the primary spectral irradiance standard of the Physikalisch-Technische Bundesanstalt in Germany.

  11. Surface biosignatures of exo-earths: remote detection of extraterrestrial life.

    Science.gov (United States)

    Hegde, Siddharth; Paulino-Lima, Ivan G; Kent, Ryan; Kaltenegger, Lisa; Rothschild, Lynn

    2015-03-31

    Exoplanet discovery has made remarkable progress, with the first rocky planets having been detected in the central star's liquid water habitable zone. The remote sensing techniques used to characterize such planets for potential habitability and life rely solely on our understanding of life on Earth. The vegetation red edge from terrestrial land plants is often used as a direct signature of life, but it occupies only a small niche in the environmental parameter space that binds life on present-day Earth and has been widespread for only about 460 My. To more fully exploit the diversity of the one example of life known, we measured the spectral characteristics of 137 microorganisms containing a range of pigments, including ones isolated from Earth's most extreme environments. Our database covers the visible and near-infrared to the short-wavelength infrared (0.35-2.5 µm) portions of the electromagnetic spectrum and is made freely available from biosignatures.astro.cornell.edu. Our results show how the reflectance properties are dominated by the absorption of light by pigments in the visible portion and by strong absorptions by the cellular water of hydration in the infrared (up to 2.5 µm) portion of the spectrum. Our spectral library provides a broader and more realistic guide based on Earth life for the search for surface features of extraterrestrial life. The library, when used as inputs for modeling disk-integrated spectra of exoplanets, in preparation for the next generation of space- and ground-based instruments, will increase the chances of detecting life.

  12. Inhabited or Uninhabited? Pitfalls in the Interpretation of Possible Chemical Signatures of Extraterrestrial Life

    Directory of Open Access Journals (Sweden)

    Stefan Fox

    2017-08-01

    Full Text Available The “Rare Earth” hypothesis—put forward by Ward and Brownlee in their 2000 book of the same title—states that prokaryote-type organisms may be common in the universe but animals and higher plants are exceedingly rare. If this idea is correct, the search for extraterrestrial life is essentially the search for microorganisms. Various indicators may be used to detect extant or extinct microbial life beyond Earth. Among them are chemical biosignatures, such as biomolecules and stable isotope ratios. The present minireview focuses on the major problems associated with the identification of chemical biosignatures. Two main types of misinterpretation are distinguished, namely false positive and false negative results. The former can be caused by terrestrial biogenic contaminants or by abiotic products. Terrestrial contamination is a common problem in space missions that search for biosignatures on other planets and moons. Abiotic organics can lead to false positive results if erroneously interpreted as biomolecules, but also to false negatives, for example when an abiotic source obscures a less productive biological one. In principle, all types of putative chemical biosignatures are prone to misinterpretation. Some, however, are more reliable (“stronger” than others. These include: (i homochiral polymers of defined length and sequence, comparable to proteins and polynucleotides; (ii enantiopure compounds; (iii the existence of only a subset of molecules when abiotic syntheses would produce a continuous range of molecules; the proteinogenic amino acids constitute such a subset. These considerations are particularly important for life detection missions to solar system bodies such as Mars, Europa, and Enceladus.

  13. The limits of extremophilic life expanded under extraterrestrial environment-simulated experiments

    Science.gov (United States)

    Lage, C.; Dalmaso, G.; Teixeira, L.; Bendia, A.; Rosado, A.

    2012-09-01

    Astrobiology is a brand new area of science that seeks to understand the origin and dynamics of life in the universe. Several hypotheses to explain life in the cosmic context have been developed throughout human history, but only now technology has allowed many of them to be tested. Laboratory experiments have been able to show how chemical elements essential to life, carbon, nitrogen, oxygen and hydrogen combine in biologically important compounds. Interestingly, these compounds are found universally. As these compounds were combined to the point of originating cells and complex organisms is still a challenge to be unveiled by science. However, our 4.5 billion years-old solar system was born within a 10-billion years-old universe. Thus, simple cells like microorganisms may have had time to form in planets older than ours or other suitable molecular places in the universe. One hypothesis to explain the origin of life on Earth is called panspermia, which predicts that microbial life could have been formed in the universe billions of years ago, traveling between planets, and inseminating units of life that could have become more complex in habitable planets like ours. A project designed to test the viability of extremophile microorganisms exposed to simulated extraterrestrial environments is ongoing at the Carlos Chagas Filho Institute of Biophysics to test whether microbial life could withstand those inhospitable environments. Ultra-resistant (known or novel ones) microorganisms collected from terrestrial extreme environments, extremophiles, have been exposed to intense radiation sources simulating solar radiation (at synchrotron accelerators), capable of emitting in a few hours radiation equivalent of million years accumulated doses. The results obtained in these experiments reveal the interesting possibility of the existence of microbial life beyond Earth.

  14. Mini-Review: Probing the limits of extremophilic life in extraterrestrial environment-simulated experiments

    Science.gov (United States)

    Lage, Claudia A. S.; Dalmaso, Gabriel Z. L.; Teixeira, Lia C. R. S.; Bendia, Amanda G.; Paulino-Lima, Ivan G.; Galante, Douglas; Janot-Pacheco, Eduardo; Abrevaya, Ximena C.; Azúa-Bustos, Armando; Pelizzari, Vivian H.; Rosado, Alexandre S.

    2012-10-01

    Astrobiology is a relatively recent scientific field that seeks to understand the origin and dynamics of life in the Universe. Several hypotheses have been proposed to explain life in the cosmic context throughout human history, but only now, technology has allowed many of them to be tested. Laboratory experiments have been able to show how chemical elements essential to life, such as carbon, nitrogen, oxygen and hydrogen combine in biologically important compounds. Interestingly, these compounds are ubiquitous. How these compounds were combined to the point of originating cells and complex organisms is still to be unveiled by science. However, our 4.5 billion years old Solar system appeared in a 10 billion years old Universe. Thus, simple cells such as micro-organisms may have had time to form in planets older than ours or in other suitable places in the Universe. One hypothesis related to the appearance of life on Earth is called panspermia, which predicts that microbial life could have been formed in the Universe billions of years ago, travelling between planets, and inseminating units of life that could have become more complex in habitable planets such as Earth. A project designed to test the viability of extremophile micro-organisms exposed to simulated extraterrestrial environments is in progress at the Carlos Chagas Filho Institute of Biophysics (UFRJ, Brazil) to test whether microbial life could withstand inhospitable environments. Radiation-resistant (known or novel ones) micro-organisms collected from extreme terrestrial environments have been exposed (at synchrotron accelerators) to intense radiation sources simulating Solar radiation, capable of emitting radiation in a few hours equivalent to many years of accumulated doses. The results obtained in these experiments reveal an interesting possibility of the existence of microbial life beyond Earth.

  15. X-ray biosignature of bacteria in terrestrial and extra-terrestrial rocks

    Science.gov (United States)

    Lemelle, L.; Simionovici, A.; Susini, J.; Oger, P.; Chukalina, M.; Rau, Ch.; Golosio, B.; Gillet, P.

    2003-04-01

    X-ray imaging techniques at the best spatial resolution and using synchrotron facilities are put forth as powerful techniques for the search of small life forms in extraterrestrial rocks under quarantine conditions (Lemelle et al. 2003). Samples, which may be collected in situ on the martian surface or on a cometary surface, will be brought back and finally stored in a container. We tested on the ID22 beamline, the possibilities of the X-ray absorption and fluorescence tomographies on sub-mm grains of NWA817 (Lemelle et al. submitted) and Tatahouine (Simionovici et al. 2001) meteorites stored in a 10 micrometer silica capillary, full of air, mimicking such containers. Studies of the X-ray microtomographies carried on reveal the positions, the 3D textures and mineralogies of the microenvironments where traces of life should be looked for in priority (with a submicrometer spatial resolution). Limitations with respect to bacterial detection are due to the difficulties to obtain information about light elements (Z techniques (Golosio et al. submitted). We tested on the ID21 beamline, the possibilities of the X-ray imaging techniques on bacteria/silicate assemblages prepared in the laboratory and directly placed in the beam. The X-ray signature of a "present" bacteria on a silicate surface was defined by X-ray mapping, out of a container, as coincident micrometer and oval zones having strong P and S fluorescence lines (S-fluorescence being slightly lower than P-fluorescence) and an amino-linked sulfur redox speciation. The X-ray signature of a single bacteria can now be applied to test the bacterial origin of nanostructures observed on some meteorite surfaces. Lemelle et al. (2003a) accepted to Journal de Physique, b submitted to Am. Min., Simionovici et al. (2001) Proc. SPIE, vol 4503, ed. U. BONSE, San Diego, August. Golosio et al. submitted to Phys. Rev. B

  16. Accretion rate of extraterrestrial {sup 41}Ca in Antarctic snow samples

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Guzmán, J.M., E-mail: jose.gomez@ph.tum.de [Technische Universität München, Fakultät für Physik, James-Franck-Strasse 1, 85748 Garching (Germany); Bishop, S.; Faestermann, T.; Famulok, N.; Fimiani, L.; Hain, K.; Jahn, S.; Korschinek, G.; Ludwig, P. [Technische Universität München, Fakultät für Physik, James-Franck-Strasse 1, 85748 Garching (Germany); Rodrigues, D. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica (Argentina)

    2015-10-15

    Interplanetary Dust Particles (IDPs) are small grains, generally less than a few hundred micrometers in size. Their main source is the Asteroid Belt, located at 3 AU from the Sun, between Mars and Jupiter. During their flight from the Asteroid Belt to the Earth they are irradiated by galactic and solar cosmic rays (GCR and SCR), thus radionuclides are formed, like {sup 41}Ca and {sup 53}Mn. Therefore, {sup 41}Ca (T{sub 1/2} = 1.03 × 10{sup 5} yr) can be used as a key tracer to determine the accretion rate of IDPs onto the Earth because there are no significant terrestrial sources for this radionuclide. The first step of this study consisted to calculate the production rate of {sup 41}Ca in IDPs accreted by the Earth during their travel from the Asteroid Belt. This production rate, used in accordance with the {sup 41}Ca/{sup 40}Ca ratios that will be measured in snow samples from the Antarctica will be used to calculate the amount of extraterrestrial material accreted by the Earth per year. There challenges for this project are, at first, the much longer time for the flight needed by the IDPs to travel from the Asteroid Belt to the Earth in comparison with the {sup 41}Ca half-life yields an early saturation for the {sup 41}Ca/{sup 40}Ca ratio, and second, the importance of selecting the correct sampling site to avoid a high influx of natural {sup 40}Ca, preventing dilution of the {sup 41}Ca/{sup 40}Ca ratio, the quantity measured by AMS.

  17. The game of active search for extra-terrestrial intelligence: breaking the `Great Silence'

    Science.gov (United States)

    de Vladar, Harold P.

    2013-01-01

    The search for extra-terrestrial intelligence (SETI) has been performed principally as a one-way survey, listening of radio frequencies across the Milky Way and other galaxies. However, scientists have engaged in an active messaging only rarely. This suggests the simple rationale that if other civilizations exist and take a similar approach to ours, namely listening but not broadcasting, the result is a silent universe. A simple game theoretical model, the prisoner's dilemma, explains this situation: each player (civilization) can passively search (defect), or actively search and broadcast (cooperate). In order to maximize the payoff (or, equivalently, minimize the risks) the best strategy is not to broadcast. In fact, the active search has been opposed on the basis that it might be dangerous to expose ourselves. However, most of these ideas have not been based on objective arguments, and ignore accounting of the possible gains and losses. Thus, the question stands: should we perform an active search? I develop a game-theoretical framework where civilizations can be of different types, and explicitly apply it to a situation where societies are either interested in establishing a two-way communication or belligerent and in urge to exploit ours. The framework gives a quantitative solution (a mixed-strategy), which is how frequent we should perform the active SETI. This frequency is roughly proportional to the inverse of the risk, and can be extremely small. However, given the immense amount of stars being scanned, it supports active SETI. The model is compared with simulations, and the possible actions are evaluated through the San Marino scale, measuring the risks of messaging.

  18. Empirical Research on Volatility Spillover Effect Between Economy Early Warning Index,National Housing Climate index and CPI Index: Based on Ternary VAR-GARCH-BEKK Model%经济预警指数、国房景气指数与CPI指数波动溢出实证分析——基于三元VAR-GARCH-BEKK模型

    Institute of Scientific and Technical Information of China (English)

    张宇青; 周应恒; 易中懿

    2014-01-01

    建立三元VAR-GARCH-BEKK模型对中国经济预警指数、国房景气指数和CPI指数间的ARCH型和GARCH型波动溢出进行了分析,发现经济预警指数和国房景气指数当期波动均受到了自身滞后残差平方与滞后波动的显著影响,但CPI指数波动不存在ARCH和GARCH效应.CPI指数对经济预警指数和国房景气指数有显著的波动溢出作用,经济预警指数对国房景气指数存在波动溢出作用.因此,国家制定宏观经济政策时应避免分割控制模式,积极建立动态制度框架和信息沟通机制以抵御风险.

  19. 企业年金基金资产结构动态优化研究——基于DCC-GARCH-CVaR模型%A Study on Asset Structure Dynamic Optimization of Occupational Pension Funds: Based on DCC-GARCH-CVaR Model

    Institute of Scientific and Technical Information of China (English)

    胡秋明; 景鹏

    2014-01-01

    资本市场震荡加剧背景下,如何通过资产结构动态调整来增强基金的保值增值能力,是我国企业年金基金投资运营管理中亟需解决的现实技术问题.论文建立DCC-GARCH-CVaR模型刻画资产间动态相关关系和度量投资组合风险,以投资组合风险最小化为目标函数,以期望收益满足最低保证要求为主要约束条件,构建企业年金基金资产结构动态调整模型.结果表明,企业年金基金最优资产结构具有一定的时变特征;资产配置最优权重是各类资产收益风险关系的权衡;资产结构的动态化与多元化是企业年金基金提升保值增值能力的必然选择.

  20. New Physics in Astrophysical Neutrino Flavor

    CERN Document Server

    Argüelles, Carlos A; Salvado, Jordi

    2015-01-01

    Recently, the IceCube collaboration announced the first detection of extra-terrestrial ultra high energy neutrinos. Astrophysical neutrinos are powerful tools to investigate the fundamental properties of particle physics through their flavor content. In this paper, we study the effect of new physics in the context of the ultra high energy neutrino flavor content. We find that in new physics dominated scenarios, the flavor content at Earth is confined to a region related to the assumed initial flavor content. Furthermore, we conclude that a precise measure of the flavor content at Earth will provide orders of magnitude improvement on new physics bounds. Finally, we discuss the current best fits of flavor content of the IceCube data and their interplay with new physics scenarios.

  1. Estimation of the extraterrestrial 3He and 20Ne fluxes on Earth from He and Ne systematics in marine sediments

    Science.gov (United States)

    Chavrit, Déborah; Moreira, Manuel; Moynier, Frédéric

    2016-04-01

    Sediments contain interplanetary dust particles (IDPs) carrying extraterrestrial noble gases, such as 3He, which have previously been used to estimate the IDP accretion flux over time and the duration of past environmental events. However, due to its high diffusivity, He can be lost by diffusion either due to frictional heating during entry in the atmosphere, or once it has been incorporated in the sediments. Therefore the absolute values of 3He IDP fluxes cannot be known. Due to its lower diffusivity, Ne is less likely to be lost by diffusion than He and can potentially provide an absolute IDP flux value. Here, we studied the Ne and He isotopic composition of 21 sediments of different ages (3 to 38 Myr, 56 Myr and 183 Myr) in order to better constrain the retention of 3He in such deposits. The samples are carbonates from 2 sites of the Integrated Ocean Drilling Program (IODP), which previously showed evidence of detectable extraterrestrial 3He, and from the Sancerre core in the Paris basin. The 3He/4He, 20Ne/22Ne and 21Ne/22Ne ratios of decarbonated residues vary respectively from 0.09×10-6 to 76.5×10-6, 9.54±0.08 to 11.30±0.60 and from 0.0295±0.0001 to 0.0344±0.0003. These isotopic compositions can be explained by a mixing between two terrestrial components (atmosphere and radiogenic He and nucleogenic Ne present in the terrigenous fractions) and an extraterrestrial component. The linear relationship between 20Ne/22Ne and 3He/22Ne ratios shows that the extraterrestrial component has a unique composition and is similar to the He and Ne composition of implanted solar wind. This composition is different from the individual stratospheric IDPs for which the Ne and He isotopic compositions have been measured. We suggest that this difference is due to a bias in the sampling of the individual IDPs previously analyzed toward the largest ones that are more likely to lose He during entry in the atmosphere. Our data further constrains the size of the majority of the

  2. Detecting The Expected Rate of Return Volatility of Financing Instruments of Indonesian Islamic Banking through GARCH Modeling (Generalized Autoregressive Conditional Heteroscedasticity

    Directory of Open Access Journals (Sweden)

    Nurul Huda

    2015-04-01

    Full Text Available Objective - Islamic banks are banks which its activities, both fund raising and funds distribution are on the basis of Islamic principles, namely buying and selling and profit sharing. Islamic banking is aimed at supporting the implementation of national development in order to improve justice, togetherness, and equitable distribution of welfare. In pursuit of supporting the implementation of national development, Islamic banking often faced stability problems of financing instruments being operated. In this case, it is measured by the gap between the actual rate of return and the expected rate of return. The individual actual RoR of this instrument will generate an expected rate of return. This raises the gap or difference between the actual rate of return and the expected rate of return of individual instruments, which in this case is called the abnormal rate of return. The stability of abnormal rate of return of individual instruments is certainly influenced by the stability of the expected rate of return. Expected rate of return has a volatility or fluctuation levels for each financing instrument. It is also a key element or material basis for the establishment of a variance of individual instruments. Variance in this case indicates the level of uncertainty of the rate of return. Individual variance is the origin of the instrument base for variance in the portfolio finance that further a portfolio analysis. So, this paper is going to analyze the level of expected RoR volatility as an initial step to see and predict the stability of the fluctuations in the rate of return of Indonesian Islamic financing instruments.Methods – Probability of Occurence, Expected Rate of Return (RoR and GARCH (Generalized Autoregressive Conditional Heteroscedasticity.Results - The expected RoR volatility of the murabaha and istishna financing instruments tend to be more volatile than expected RoR volatility of musharaka and qardh financing instruments

  3. 基于GARCH模型的金融市场波动性分析与预测%Analysis and Prediction of Financial Market Volatility Based on GARCH Model

    Institute of Scientific and Technical Information of China (English)

    洪晶晶; 吴鹏跃

    2016-01-01

    以上证指数2004年1月2日至2014年12月28日交易日收盘价格的实际数据为样本,采取两种不同的波动率定义方式分别建立上证指数波动率的GARCH模型,并对两种波动率进行预测对比分析,实证研究结果表明以标准差定义的波动率建立GARCH(1,1)模型进行未来波动率预测的拟合效果较好。%Taking the actual dada of the trading day closing price of Shanghai securities composite index from Jan.2, 2004 to Dec. 28, 2014 as the sample, two ways of volatility definition are used to build the GARCH model of Shanghai securities composite index respectively. The prediction comparison of the two kinds of volatility are analyzed. The empirical research result shows that the imitative effect of using standard deviation defined volatility to build GARCH(1,1)model for future volatility forecasting is better.

  4. 两类多元GARCH模型的预测绩效和组合VaR的研究%The Forecast Performance of Two Style GARCH Models and Portfolio VaR Computation

    Institute of Scientific and Technical Information of China (English)

    吕轶; 陈荣达; 刘剑波

    2009-01-01

    运用VaR模型对股票组合进行风险测度的关键之一是得到组合条件协方差矩阵.而经典的多元GARCH模型来求解波动率面临着估计参数过多,计算量庞大的问题.因此,使用正交GARCH模型和CCC模型来估算波动率,并以沪深两市A股市场上四个行业的65只股票为样本,使用RMSE和MAD指标比较这些模型的预测能力,求得股票组合的VaR,得出前者效率高和后者预测能力略高的结论.%The conditional covariance matrix plays a critical role in portfolio VaR computation. However, in the classical multivariate GARCH model large-scale portfolio is highly parameterized and difficult to estimate in practice. So this paper uses O-GARCH model and CCC model to calculate the volatilities of portfolio. Then 65 samples of stocks in A stock market of Shanghai and Shenzhen is examined by these models. Finally, we follow two criteria to judge the quality of the volatility forcasts and compute portfolio VaR by the conditional covariance matrix.

  5. On the Search for the Amino Acids on the Lunar Surface as it Relates to Other Extraterrestrial Bodies

    Science.gov (United States)

    Hoover, Richard B.; Kolb, Vera M.

    2009-01-01

    The early search for the amino acids on the lunar surface fines indicated such a low amount of the amino acids that it was deemed insignifi cant. While the later studies seemed to depart in some ways from the earlier results, they were not pursued. In this paper we critically ev aluate the results from the Apollo missions from the new perspective with considerations of the sensitivity of the instrumentation availabl e at the time. We discuss the possible relevance of the lunar results to the findings of the amino acids on the surfaces of other extraterrestrial bodies, such as Mars.

  6. The introduction of an additional probability coefficient in evaluating the possibility of the existence of extraterrestrial intelligent beings

    Science.gov (United States)

    Barth, H.

    An hypothesis is presented concerning the crucial influence of tides on the evolutionary transition from aquatic to land animal forms. The hypothesis suggests that the evolution of higher forms of life on a planet also depends on the existence of a planet-moon system in which the mass ratio of both constituents must be approximately equal to that of the earth-moon system, which is 81:1. The hypothesis is taken into account in the form of the probability factor fb in Drake's formula for estimating the presumed extraterrestrial civilizations in Milky Way which may conceivably make contact.

  7. Extraterrestrial Impact Event Recorded in the Late Triassic Deep-Sea Deposits from Japan

    Science.gov (United States)

    Sato, H.; Shirai, N.; Ebihara, M.; Nozaki, T.; Suzuki, K.; Onoue, T.; Kiyokawa, S.

    2014-12-01

    The Late Triassic is marked by the formation of several large impact structures on the Earth, including the 90-km-diameter Manicouagan crater in Canada (Spray and Kelly, 1998). Anomalously high platinum group element (PGE) concentrations have been reported from the Upper Triassic deep-sea deposits in Japan, which have been interpreted to be derived from an extraterrestrial impact event forming the Manicouagan crater (Onoue et al., 2012; Sato et al., 2013). However, previous studies have not clarified the composition of the projectile. Here we report the PGE element ratios and osmium (Os) isotopic compositions of the Upper Triassic ejecta layers in Japan in order to understand the projectile component. Evidence for the Late Triassic impact event has been discovered in the deep-sea claystone layers at four bedded chert sections in the Japanese accretionary complex. The claystone layers contain microspherules, Ni-rich magnetite grains and high abundance of PGEs (Onoue et al., 2012). Biostratigraphic analysis of radiolarian fossils from the studied sections revealed that the claystone layers occur embedded in the upper middle Norian (Sugiyama, 1997; Onoue et al., 2012). Identification of the projectile is attempted by comparing the isotope and elemental ratios of the ejecta deposit with similar data obtained from meteorites. The Ru/Ir and Pt/Ir ratios of all the claystone samples from the study sites are plotted along the mixing line between chondrites and upper continental crust. Although chondrites cannot be distinguished from iron meteorites by using PGE/Ir ratios, the claystone layers have Cr/Ir ratios between 104-105, indicating that the claystone layers are clearly contaminated by chondritic material. The Os isotope data show an abrupt and marked negative excursion from an initial Os isotope ratio of ~0.477 to unradiogenic values of ~0.126 in a claystone layer within a middle Norian bedded chert, indicating the input of chondrite-derived Os into seawater. The

  8. A revolutionary lunar space transportation system architecture using extraterrestrial LOX-augmented NTR propulsion

    Science.gov (United States)

    Borowski, Stanley K.; Corban, Robert R.; Culver, Donald W.; Bulman, Melvin J.; McIlwain, Mel C.

    1994-08-01

    The concept of a liquid oxygen (LOX)-augmented nuclear thermal rocket (NTR) engine is introduced, and its potential for revolutionizing lunar space transportation system (LTS) performance using extraterrestrial 'lunar-derived' liquid oxygen (LUNOX) is outlined. The LOX-augmented NTR (LANTR) represents the marriage of conventional liquid hydrogen (LH2)-cooled NTR and airbreathing engine technologies. The large divergent section of the NTR nozzle functions as an 'afterburner' into which oxygen is injected and supersonically combusted with nuclear preheated hydrogen emerging from the NTR's choked sonic throat: 'scramjet propulsion in reverse.' By varying the oxygen-to-fuel mixture ratio (MR), the LANTR concept can provide variable thrust and specific impulse (Isp) capability with a LH2-cooled NTR operating at relatively constant power output. For example, at a MR = 3, the thrust per engine can be increased by a factor of 2.75 while the Isp decreases by only 30 percent. With this thrust augmentation option, smaller, 'easier to develop' NTR's become more acceptable from a mission performance standpoint (e.g., earth escape gravity losses are reduced and perigee propulsion requirements are eliminated). Hydrogen mass and volume is also reduced resulting in smaller space vehicles. An evolutionary NTR-based lunar architecture requiring only Shuttle C and/or 'in-line' shuttle-derived launch vehicles (SDV's) would operate initially in an 'expandable mode' with NTR lunar transfer vehicles (LTV's) delivering 80 percent more payload on piloted missions than their LOX/LH2 chemical propulsion counterparts. With the establishment of LUNOX production facilities on the lunar surface and 'fuel/oxidizer' depot in low lunar orbit (LLO), monopropellant NTR's would be outfitted with an oxygen propellant module, feed system, and afterburner nozzle for 'bipropellant' operation. The LANTR cislunar LTV now transitions to a reusable mode with smaller vehicle and payload doubling benefits on

  9. Enantioselective separation of amino acids as biomarkers indicating life in extraterrestrial environments.

    Science.gov (United States)

    Pietrogrande, Maria Chiara

    2013-10-01

    Traces of prebiotic amino acids, i.e., the building blocks of proteins, are excellent biomarkers that could provide evidence of extinct or extant life in extra-terrestrial environments. In particular, characterization of the enantiomeric excess of amino acids gives relevant information about the biotic or abiotic origin of molecules, because it is generally assumed that life elsewhere could be based on either L or D amino acids, but not both. The analytical procedures used in in-situ space missions for chiral discrimination of amino acids must meet severe requirements imposed by flight conditions: short analysis time, low energy consumption, robustness, storage for long periods under extreme conditions, high efficiency and sensitivity, automation, and remote-control operation. Such methods are based on gas chromatography, high-pressure liquid chromatography, and capillary electrophoresis, usually coupled with mass spectrometry; of these, gas chromatography-mass spectrometry (GC-MS) is the only such combination yet used in space missions. Preliminary in-situ sample derivatization is required before GC-MS analysis to convert amino acids into volatile and thermally stable compounds. The silylation reagent most commonly used, N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide, is unsuitable for detection of homochirality, and alternative derivatization techniques have been developed that preserve the stereochemical configuration of the original compounds and are compatible with spaceflight conditions. These include the reagent N,N-dimethylformamide dimethylacetal, which has already been used in the Rosetta mission, a mixture of alkyl chloroformate, ethanol, and pyridine, a mixture of perfluorinated anhydrides and perfluoro alcohols, and hexafluoroacetone, the first gaseous derivatizing agent. In all the space instruments, solvent extraction of organic matter and chemical derivatization have been combined in a single automatic and remote-controlled procedure in a

  10. Instrumentation and vehicle platform of a miniaturized submersible for exploration of terrestrial and extraterrestrial aqueous environments

    Science.gov (United States)

    Jonsson, Jonas; Sundqvist, Johan; Nguyen, Hugo; Berglund, Martin; Ogden, Sam; Palmer, Kristoffer; Smedfors, Katarina; Johansson, Linda; Hjort, Klas; Thornell, Greger

    2012-10-01

    An example of an extraterrestrial environment likely to support life is the vast liquid body believed to hide underneath the frozen crust of Jupiter's moon Europa. The hypothetical exploration of this, as well as the more accessible subglacial lakes on Earth, has been used as model applications for the development of a heavily miniaturized, yet qualified, submersible with the potential to be deployable either in itself through a long and narrow borehole or as the daughter craft of an ice-penetrating cryobot. Onboard the submersible, which is only 20 cm in length and 5 cm in diameter, accommodation of a versatile set of sensors and instruments capable of characterizing and imaging the surroundings, and even collecting water samples with microorganisms for return, is facilitated through the use of miniaturization technologies. For instance, together with a small camera, a laser-based, microoptic device enables the 3-D reconstruction of imaged objects for topographical measurements. As a complement, when the water is turbid or a longer range is wanted, the world's smallest side-scanning sonar, exhibiting centimeter resolution and a range of over 30 m, has been developed. The work on miniaturizing a CTD, which is a widely employed oceanographic instrument used to measure and correlate conductivity, temperature, and depth, has commenced. Furthermore, a device employing acoustics to trap microscopic particles and organisms, and, by this, enrich water samples, is under development. To ensure that the gathered samples are pristine until analyzed at the end of a mission, the device is equipped with high-pressure, latchable valves. Remote operation and transfer of measurement data and images, or even live streaming of video, is made possible through a kilometer-long fiber optic cable being reeled out from the vehicle underway and tethering it to a terminal. To extend the missions, the same fiber shall also be capable of charging the onboard batteries. In this paper, the

  11. Laser induced fluorescence and Raman spectroscopy in capillary electrophoresis as an possible instrument for extraterrestrial life signs detection.

    Science.gov (United States)

    Mikhail, Gorlenko; Cheptcov, Vladimir; Anton, Maydykovskiy; Eugeniy, Vasilev

    The one of a significant aims in extraterrestrial exploration is a seeking for a life traces in a open space and planetary objects. Complex composition and unknown origin of suspected signs of life required у new analytical approaches and technical solutions. The promising assai here can be Laser induced fluorescence and Raman spectroscopy methods. The combined instrument developed by our team reveal the advantage of capillary electrophoresis assays in a junction with laser induced fluorescence detection technology. We optimized excitation configuration of fluorescence in capillary electrophoresis to reduce pumping laser power up to 1 mW and decrease background scattering. The improvement of the device sensitivity at poor sample concentration we achieved by incorporating fluorescence flow-through cuvette into spectrometer. That allows to simplify setup, to minimize weight and increase reproducibility of measurements. The device has been tasted in complex organic chemical mixes and microbial strains differentiation tasks. 3d multinational spectra allow us to increase the spectra information loads in comparison with ordinary capillary electrophoresis approaches. Possible updating the device with Raman approach can even furthermore multiple the differentiation power of the instrument. The analytical module developed using this approach can be potentially effectively used in extraterrestrial researches as a payload of the future spacecraft.

  12. Sampling the Radio Transient Universe: Studies of Pulsars and the Search for Extraterrestrial Intelligence

    Science.gov (United States)

    Chennamangalam, Jayanth

    The transient radio universe is a relatively unexplored area of astronomy, offering a variety of phenomena, from solar and Jovian bursts, to flare stars, pulsars, and bursts of Galactic and potentially even cosmological origin. Among these, perhaps the most widely studied radio transients, pulsars are fast-spinning neutron stars that emit radio beams from their magnetic poles. In spite of over 40 years of research on pulsars, we have more questions than answers on these exotic compact objects, chief among them the nature of their emission mechanism. Nevertheless, the wealth of phenomena exhibited by pulsars make them one of the most useful astrophysical tools. With their high densities, pulsars are probes of the nature of ultra-dense matter. Characterized by their high timing stability, pulsars can be used to verify the predictions of general relativity, discover planets around them, study bodies in the solar system, and even serve as an interplanetary (and possibly some day, interstellar) navigation aid. Pulsars are also used to study the nature of the interstellar medium, much like a flashlight illuminating airborne dust in a dark room. Studies of pulsars in the Galactic center can help answer questions about the massive black hole in the region and the star formation history in its vicinity. Millisecond pulsars in globular clusters are long-lived tracers of their progenitors, low-mass X-ray binaries, and can be used to study the dynamical history of those clusters. Another source of interest in radio transient astronomy is the hitherto undetected engineered signal from extraterrestrial intelligence. The Search for Extraterrestrial Intelligence (SETI) is an ongoing attempt at discovering the presence of technological life elsewhere in the Galaxy. In this work, I present my forays into two aspects of the study of the radio transient universe---pulsars and SETI. Firstly, I describe my work on the luminosity function and population size of pulsars in the globular

  13. 基于GARCH-EVT-VaR模型的国际主要碳排放交易市场风险度量研究%The Study on Measuring the Risk of Major International Carbon Emissions Trading Market Based on the Model of GARCH-EVT-VaR

    Institute of Scientific and Technical Information of China (English)

    田园; 陈伟; 宋维明

    2015-01-01

    选取欧洲碳排放权交易系统现货和期货数据,以及芝加哥气候环境交易所的数据,根据在险值理论、条件方差理论以及极值理论,构造GARCH-EVT-VaR模型,度量上述两个市场的正常波动和极端情况下的期望风险。对比两个市场的波动情况、市场效率以及市场风险,本文发现碳排放权交易市场下跌风险更大,并且下跌的信息对于市场的影响更明显。另外,认为强制性交易市场更适合碳排放权交易,且期货交易的引入增大了碳交易市场的不确定性。%This paper selects spot and future data of EU ETS and the data of CCX to evaluate the risk of the two markets under extreme conditions or in order by GARCH-EVT-VaR model based on the value-at risk theory,the conditional variance theory and the extreme value theory.Compared with volatility,efficiency and risk of the two markets,it indicates that the downside risk is greater than the upside risk;the information of downside risk has more impact on the markets.It also shows that the mandatory market is more suitable for carbon trading and the futures make the carbon market more un-certain.

  14. Risk Measure of Electricity Market Based on ARMAX-GARCH Modal with Conditional Skewed-t Distribution and Extreme Value Theory%基于条件有偏t分布ARMAX-GARCH模型和极值理论的电力市场风险测度研究

    Institute of Scientific and Technical Information of China (English)

    王瑞庆; 王晛; 李渝曾

    2013-01-01

    在对电价的基本特征综合分析的基础上,采用残差服从时变偏度和自由度的有偏t分布ARMAX-GARCH(ARMAX-GARCH-VST)模型对电价序列的相关性、有偏性、多季节性、异方差性和波动集聚性进行过滤,以获得统计特性更好的独立同分布残差序列,然后运用极值理论描述ARMAX-GARCH-VST模型归一化残差的尾部分布,以获得更加精确的VaR估计.基于PJM电力市场历史数据的分析表明,ARMAX-GARCH-VST模型和ARMAX-GARCH-EVT模型都能对现货电价的变化做出比较迅速的反应,VaR的估计结果在各个置信水平下均准确有效,但ARMAX-CARCH-EVT模型的VaR估计结果更加准确,表现出了更好的动态特征.该结果对于电力市场参与者准确地测度价格波动风险和制定有效的风险规避策略具有重要的指导意义.

  15. Geodetic reference systems for long period studies in earth physics

    Science.gov (United States)

    Mather, R. S.

    1973-01-01

    A simple system of reference axes is defined for possible use in high precision geodetic studies over long periods of time for programs in earth physics. The proposed system is based on the gravitational and dynamic characteristics of the axis of rotation and the earth's center of mass as defined instantaneously at a given epoch. Techniques are outlined for its continuous representation over time intervals of significance for studies in earth physics. The relationship between the proposed system and the representation of extra-terrestrial objects using the celestial sphere concept is also discussed.

  16. Forecast and Fit for Exchange Rate of Yen against Dollar Using GARCH Model%运用GARCH模型对日元兑美元汇率序列的拟合与预测

    Institute of Scientific and Technical Information of China (English)

    陈伟伟

    2009-01-01

    近来,日元对美元汇率的变动日益成为影响东亚经济增长与稳定的一个极为重要因素.因此,本文基于Eviews软件系统,运用GARCH模型分析方法模拟日元兑美元序列的波动情况.结果表明:日元兑美元序列存在自相关性和异方差性,用GARCH(1,1)模型能较好的模拟该序列的波动特征.

  17. Evaluating the flux of extraterrestrial osmium at the onset of Younger Dryas in the GRIP ice core

    Science.gov (United States)

    Seo, J. H.; Han, C.; Hong, S.; Steffensen, J. P.; Sharma, M.

    2016-12-01

    The Younger Dryas (YD: 12.9-11.6 ka) was an abrupt cooling event during the last deglaciation. The mechanism behind the cooling is suggested to be a temporary slowdown of North Atlantic thermohaline circulation due to catastrophic release of meltwater from proglacial Lake Agassiz during the retreat of the Laurentide Ice Sheet [1]. An alternative hypothesis states that the cooling was directly/indirectly triggered by one or more cosmic airbursts/impacts [2]. While several papers have documented evidence for a YD extraterrestrial impact including microspherules, nanodiamonds, magnetic grains, and glass-like carbon [4-7], this hypothesis remains controversial [8-10]. In a recent study by Petaev et al. [11], an unusually high Pt/Ir ratio of 1200 was discovered in the GISP-2 ice core at the onset of YD, indicating a large Pt enriched iron meteorite impact. Such a high Pt/Ir in extraterrestrial materials has not been documented [12]. Thus, Petaev et al. [11] acknowledge that the interpretation of the Pt anomaly is based on circumstantial evidence. The distinct Os isotopic composition (187Os/188Os ratio) of the terrestrial (=1.26) and extraterrestrial (= 0.13) sources should allow us to evaluate if there was a meteorite impact at the YD boundary. These analyses are technically challenging owing to rather low concentration of Os in ice-melts ( 1x10-15g/g). Here, we will present Os isotope data from the GRIP ice core spanning the time period through YD to shed light on the meteorite/comet impact hypothesis. [1] Broecker et al. (1989) Nature 341, 318-321; [2] Firestone et al. (2007) PNAS. 104, 16016-16021; [3] Bunch et al. (2012) PNAS. 109, 1903-1912; [4] LeCompte et al. (2012) PNAS. 109, 2960-2969; [5] Wittke et al. (2013) PNAS 110, 2088-2097; [6] Wu et al. (2013) PNAS. 110, 3557-3566; [7] Kennett et al. (2015) PNAS 112, E4344-E4353; [8] Pinter et al. (2011) Earth Sci. Rev., 106, 247-264; [9] Holliday et al. (2014) J. Quat. Sci. 29, 515-530; [10] Meltzer et al. (2014) PNAS

  18. Risk Evaluation in Fuel Oil Futures Market Based on VaR-GARCH Dynamic Model%基于VaR-GARCH族动态模型的燃料油期货市场风险测量

    Institute of Scientific and Technical Information of China (English)

    戴毓; 周德群

    2009-01-01

    In this paper,we build a dynamic VaR-GARCHs evaluation model of the single futures contract in Shanghai fuel oil futures market was given.Based on VaR,the dynamic VaR-GARCH evaluation model can effectively forecast the range of volatility in the future well and truly.Furthermore,it is workable in forewarning and monitoring market risks.Considering actual futures margin rate in Shanghai fuel oil futures market,a new rate setting model(RCM)was obtained with corrected futures margin rate.RCM absorbs the advantages of margin rate setting techniques used at home and aborad.As a result,it can effectively control and avoid market risks,thus increasing the efficiency of fund utilization.%针对上海燃料油期货市场,基于VaR方法,建立了单个期货合约的VaR-GARCH族动态测量模型.实证结果表明,该模型可以较准确地预测未来价格波动范围,并具有较好的风险预警、风险监控作用.针对燃料油期货的现行保证金比例,本文给出修正后的保证金比例井提出了一种新型的保证金设定模型,该模型结合了国内、外确定期货保证金方法的优点,在有效地控制和规避市场风险的基础上提高了资金使用效率.

  19. Análisis de la volatilidad del índice principal del mercado bursátil mexicano, del índice de riesgo país y de la mezcla mexicana de exportación mediante un modelo GARCH trivariado asimétrico || Volatility Analysis of the Core Mexican Stock Market Index, the Country Risk Index, and the Mexican Oil Basket Using an Asymmetric Trivariate GARCH Model

    Directory of Open Access Journals (Sweden)

    Villalba Padilla, Fátima Irina

    2014-12-01

    Full Text Available Se parametriza de forma conjunta€€ la heteroscedasticidad condicional autorregresiva generalizada que corresponde al comportamiento de la varianza de tres variables: (a el índice de precios y cotizaciones (IPC, indicador principal del mercado bursátil mexicano, (b el emerging markets bond index para México (EMBI, como indicador de riesgo país y (c el precio de la canasta mexicana de tres crudos de exportación (MEZCLA. Las variables se emplean como estimadores de la tendencia de los precios de las acciones, los bonos y los energéticos, respectivamente, con el objetivo final de conformar un portafolio de inversión diversicado que incluya dichos activos. Se presentan los resultados empíricos de un modelo econométrico GARCH trivariado asimétrico. El modelo permite incorporar la covarianza entre las variables para explicar su interrelación y en la estimación se considera el efecto de los choques generados por las innovaciones positivas y negativas. El estudio contempla el periodo de 2002 a 2013. || We jointly parameterized the generalized autoregressive conditional heteroskedasticity that corresponds to the behavior of the variance of three variables: (a the core Mexican stock market index (IPC, (b the Emerging Markets Bond Index for Mexico (EMBI as country risk pointer and, (c the Mexican three oil basket exports mix (MEZCLA. The variables are used as trend indicators of stocks, bonds and energetics respectively with the ultimate goal of forming a diversified portfolio including such assets. This paper presents the empirical results of an asymmetric econometric trivariate GARCH model. The model incorporates the covariance between the variables in order to explain their relationship and we considered the shocks generated by positive and negative innovations. The study involves the period 2002- 2013.

  20. Palaeoclimatic Cycles,Global Environmental Changes and New Glacial Periods Induced by the Impact of Extraterrestrial Bodies

    Institute of Scientific and Technical Information of China (English)

    王世杰; 欧阳自远; 等

    1999-01-01

    In terms of Earth-Sun geometry,the Milankovitch theory has successfully explained most of the cyclie palaeoclimatic variations during the history of the Earth,especially in the Quaternary.In this paper,the authors suggest that the impact of extraterrestrial bodies on the Earth may be another mechanism to cause palaeoclimatic cycles,global environmental changes and new glacial periods,Based on geological and geochemical records in the boundary layers produced by six huge Cenozoic bolide-impact events(65,34,15,2.4,1.1,0.73Ma B.P.),including those at 34,15,1.1and 0.73MaB.P.which are represented by four famous tektite-strewn fields,the process and mechanics of palaeoclimatic cycles and global environmental eatastrophes induced by extraterrestrial impact are discussed in detail.Impact-generated dust.soot and aerosol floating in the staratosphere could result in short-term(<1year),rapid drop in tempeature immediately after impact.Through self-regulation of the Earth's climate system,the temperature at the surface slowly went up within 100a and maintained stable for a long time at 250K.If there were no other factors leading to the break-down of the nely-established equilibrium,a new glaciel peood would be initiated.Estimating from the thickess of δ13C and δ18O anomalies in sediments across the impact boundary layer and deposition rate,the duration of two stages of the palaeoclimate cycle in the form of cold weather-greenhouse effect-normal weather war 104-105a ,respectively.The conclusion deduced from the above model is supported by palaeotemperature change recorded by oxygen isotope in sediments across the impact boundary layer.

  1. Survival of akinetes (resting-state cells of cyanobacteria) in low earth orbit and simulated extraterrestrial conditions.

    Science.gov (United States)

    Olsson-Francis, Karen; de la Torre, Rosa; Towner, Martin C; Cockell, Charles S

    2009-12-01

    Cyanobacteria are photosynthetic organisms that have been considered for space applications, such as oxygen production in bioregenerative life support systems, and can be used as a model organism for understanding microbial survival in space. Akinetes are resting-state cells of cyanobacteria that are produced by certain genera of heterocystous cyanobacteria to survive extreme environmental conditions. Although they are similar in nature to endospores, there have been no investigations into the survival of akinetes in extraterrestrial environments. The aim of this work was to examine the survival of akinetes from Anabaena cylindrica in simulated extraterrestrial conditions and in Low Earth Orbit (LEO). Akinetes were dried onto limestone rocks and sent into LEO for 10 days on the ESA Biopan VI. In ground-based experiments, the rocks were exposed to periods of desiccation, vacuum (0.7×10(-3) kPa), temperature extremes (-80 to 80°C), Mars conditions (-27°C, 0.8 kPa, CO(2)) and UV radiation (325-400 nm). A proportion of the akinete population was able to survive a period of 10 days in LEO and 28 days in Mars simulated conditions, when the rocks were not subjected to UV radiation. Furthermore, the akinetes were able to survive 28 days of exposure to desiccation and low temperature with high viability remaining. Yet long periods of vacuum and high temperature were lethal to the akinetes. This work shows that akinetes are extreme-tolerating states of cyanobacteria that have a practical use in space applications and yield new insight into the survival of microbial resting-state cells in space conditions.

  2. Correlated variations and periodicity of global CO{sub 2}, biological mass extinctions and extra-terrestrial bolide impacts over the past 250 million years and possible geodynamical implications

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, R.k.; Rao, K.N.N. [National Geophysical Research Institute, Hyderabad (India). Theoretical Geophysics Group

    1998-12-31

    Earth`s history has been witness to recurrently alternating phases of catastrophic evolution and dominant tectonic deformations, contractions and extension of rifting and spreading leading to quasi-cyclic changes in sedimentary environment and various earth processes. Recent studies have shown quasi-periodicities of 32{+-}2 Million years (Myr) in various endogenic (geomagnetic reversals, magmatic events, mantle convection, various tectonic activities, climate change and biological extinctions) and exogenic (impact catering) processes indicating a remarkable kinship. A time series analysis is presented of the available CO{sub 2} record over the past 250 Myr decoded from global CaCO{sub 3} accumulation rates in sedimentary environment. The time series analysis reveals an intriguing evidence of a dominant periodicity of 33{+-}2 Myr which matches closely with a `common catastrophic periodicity` of 32 Myr identified in various terrestrial and extra-terrestrial records. The authors argue for a common physical link among the periodic global CO{sub 2} variations, mantle convection, geomagnetic reversals, volcanism, geotectonic cycles and enhanced cometary showers. Periodic variations in CO{sub 2} are suggested as one of the possible terrestrial stimulators for the oscillating `greenhouse effect` and related climatic deterioration that result in quasi-periodic mass extinctions. Identifical catastrophic cycles of endogenic and exogenic origin enhance the credence of their physical linkages and uphold the concept of non-uniformitarianism in earth`s processes. 55 refs., 4 figs., 2 tabs.

  3. Correlated variations and periodicity of global CO[sub 2], biological mass extinctions and extra-terrestrial bolide impacts over the past 250 million years and possible geodynamical implications

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, R.k.; Rao, K.N.N. (National Geophysical Research Institute, Hyderabad (India). Theoretical Geophysics Group)

    1998-01-01

    Earth's history has been witness to recurrently alternating phases of catastrophic evolution and dominant tectonic deformations, contractions and extension of rifting and spreading leading to quasi-cyclic changes in sedimentary environment and various earth processes. Recent studies have shown quasi-periodicities of 32[+-]2 Million years (Myr) in various endogenic (geomagnetic reversals, magmatic events, mantle convection, various tectonic activities, climate change and biological extinctions) and exogenic (impact catering) processes indicating a remarkable kinship. A time series analysis is presented of the available CO[sub 2] record over the past 250 Myr decoded from global CaCO[sub 3] accumulation rates in sedimentary environment. The time series analysis reveals an intriguing evidence of a dominant periodicity of 33[+-]2 Myr which matches closely with a 'common catastrophic periodicity' of 32 Myr identified in various terrestrial and extra-terrestrial records. The authors argue for a common physical link among the periodic global CO[sub 2] variations, mantle convection, geomagnetic reversals, volcanism, geotectonic cycles and enhanced cometary showers. Periodic variations in CO[sub 2] are suggested as one of the possible terrestrial stimulators for the oscillating 'greenhouse effect' and related climatic deterioration that result in quasi-periodic mass extinctions. Identifical catastrophic cycles of endogenic and exogenic origin enhance the credence of their physical linkages and uphold the concept of non-uniformitarianism in earth's processes. 55 refs., 4 figs., 2 tabs.

  4. Research on risk and performance of precious metals investments in China based on GED-GARCH model%基于 GED-GARCH 模型的中国贵金属投资风险与绩效研究

    Institute of Scientific and Technical Information of China (English)

    杨克磊; 桂海意

    2014-01-01

    为了度量和比较中国金、银、铂3种主要贵金属现货投资的风险与收益,在验证3种贵金属现货资产收益率序列具有尖峰、厚尾和波动集聚性特征的基础上,运用基于GED-GARCH模型的VaR方法度量3种贵金属现货的投资风险,并以同期上证综指的表现为参照基准,依据RAROC指标对3种贵金属现货的投资绩效进行比较和评价。实证结果表明,黄金资产的风险最小,铂金次之,两者均小于同期上证综指,白银资产的风险与同期上证综指相当;从风险调整后的综合业绩表现来看,投资黄金的回报最优,白银次之,两者都优于上证综指,而铂金的回报略差于同期上证综指。%In order to measure and compare the risk and performance of gold,silver and platinum spots invest-ments,the paper first proved that the return series of Au(T+D),Ag(T+D) and Pt 99.95 spots had the typical char-acteristics of skewed,leptokurtic,fat tailed and volatility clustering,then used the GED-GARCH model and VaR meth-od to measure the risk of the three assets,and at last compared and evaluated the performance of the three assets with the Shanghai Composite Index based on RAROC index.The results show that the risk of gold is smaller than platinum, and they are both smaller than Shanghai Composite Index,the risk of silver is equal to Shanghai Composite Index;the performance of gold investment is better than silver,and they are both better than Shanghai Composite Index,the per-formance of platinum investment can't catch Shanghai Composite Index.

  5. If the universe is teeming with aliens where is everybody? fifty solutions to the Fermi paradox and the problem of extraterrestrial life

    CERN Document Server

    Webb, Stephen

    2002-01-01

    Given the fact that there are perhaps 400 million stars in our Galaxy alone, and perhaps 400 million galaxies in the Universe, it stands to reason that somewhere out there, in the 14-billion-year-old cosmos, there is or once was a civilization at least as advanced as our own. The sheer enormities of the numbers almost demand that we accept the truth of this hypothesis. Why, then, have we encountered no evidence, no messages, no artifacts of these extraterrestrials? Webb discusses in detail the 50 most cogent and intriguing solutions to Fermi's famous paradox: If the numbers strongly point to the existence of extraterrestrial civilizations, why have we found no evidence of them?

  6. If the Universe is teeming with aliens... where is everybody? seventy-five solutions to the Fermi paradox and the problem of extraterrestrial life

    CERN Document Server

    Webb, Stephen

    2015-01-01

    Given the fact that there are perhaps 400 billion stars in our Galaxy alone, and perhaps 400 billion galaxies in the Universe, it stands to reason that somewhere out there, in the 14-billion-year-old cosmos, there is or once was a civilization at least as advanced as our own. The sheer enormity of the numbers almost demands that we accept the truth of this hypothesis. Why, then, have we encountered no evidence, no messages, no artifacts of these extraterrestrials? In this second, significantly revised and expanded edition of his widely popular book, Webb discusses in detail the (for now!) 75 most cogent and intriguing solutions to Fermi's famous paradox: If the numbers strongly point to the existence of extraterrestrial civilizations, why have we found no evidence of them?

  7. Utilizing an Extraterrestrial Analogue to Predict Sediment Migration on Frenchman Flat due to Convective Vortex (Dust Devil) Activity

    Science.gov (United States)

    McGee, B. W.

    2006-12-01

    A synthesis of terrestrial and Martian data suggests that a convective vortex, or "dust devil," is a significant, non-random terrestrial eolian sediment transport phenomenon, which has implications for sediment-based migration of radionuclides on Frenchman Flat playa, a 20 square-mile mountain-bounded dry lake bed approximately centered in Frenchman Flat on the Nevada Test Site (NTS). Planetary scientists are often forced to rely on terrestrial analogues to begin characterizing extraterrestrial processes. However, as the planetary database matures, an increasing number of well-characterized extraterrestrial analogues for terrestrial processes will become available. Such analogues may provide a convenient means to investigate poorly understood or otherwise inaccessible terrestrial phenomena. Historical atmospheric nuclear experiments conducted from 1951 to 1962 deposited radionuclides into surface sediments across parts of Frenchman Flat playa, where dust devils are known to commonly occur, especially during the summer months. Recent information from both terrestrial and Martian studies yields that dust devils can be significant contributors to both the local eolian sediment transport regime and the regional climate system. Additionally, the use of terrestrial desert environments as Martian analogues, as well as the recent, unique discovery of Mars-like dust devil tracks in Africa, has established a working correlation between Earth, Mars, and the dust devil phenomenon. However, while the difficulty in tracking dust devil paths on Earth has hindered the determination of any net sediment transport due to dust devils, the dramatic albedo contrast in disturbed sediment on Mars lends to the formation of persistent, curvilinear dust devil tracks. These tracks illustrate that in zones of preferential formation, dust devils possess non-random orientations over seasonal timescales with respect to prevailing wind. By calibrating these Martian orientations with meteorological

  8. 基于3σ准则的分段拟合及其GARCH修正模型%Piecewise Fitting based on 3σGuidelines and its Garch Remaining Modified model

    Institute of Scientific and Technical Information of China (English)

    林静; 唐国强; 覃良文

    2016-01-01

    在金融时间序列中,一组金融序列可被视为由不同时间段的分段函数拟合连接而成。利用3σ准则确定分段函数的临界点,并根据 AIC准则及调整后R2对分段点进行验证,从而分段点把数据分割成两部分。对两序列分别用合适的函数进行拟合,并用 ARMA-GARCH模型对残差序列进行修正。由上证综合指数数据的实证分析结果表明:3σ准则能很好地检索出临界点,同时建立的分段函数模型预测效果要优于 ARMA与 EGARCH模型,以及 ARMA-GARCH模型的引入对模型的精确度有所提高。所介绍的方法简单易懂、便于操作、精度高,为金融投资者和学者提供参考价值。%In the financial time series,a group of financial sequence can be used as a function,in which piecewise fitting connection is made in different time periods.The Pauta criterion was exploited to determine the critical point of piecewise func-tions,according to AIC guidelines and coefficient of determination after adj ustment to test breaking point,thus the staging point split the data into two parts.Two sequences were fitted with the appropriate function,and ARMA-GARCH model was used to amend the residual sequence.The empirical results of Shanghai composite index show that the 3σguidelines can retrieve critical point commendably.At the same time,the forecasting efficiency of piecewise function model is better than ARMA mod-el and EGARCH model.Also,the precision of the model is improved by the introduction of ARMA-GARCH model.Moreo-ver,the method is simple,easy to understand and operate,and accurate,which provides reference value for financial investors and scholars.

  9. Study of extraterrestrial disposal of radioactive wastes. Part 2: Preliminary feasibility screening study of extraterrestrial disposal of radioactive wastes in concentrations, matrix materials, and containers designed for storage on earth

    Science.gov (United States)

    Hyland, R. E.; Wohl, M. L.; Thompson, R. L.; Finnegan, P. M.

    1972-01-01

    The results are reported of a preliminary feasibility screening study for providing long-term solutions to the problems of handling and managing radioactive wastes by extraterrestrial transportation of the wastes. Matrix materials and containers are discussed along with payloads, costs, and destinations for candidate space vehicles. The conclusions reached are: (1) Matrix material such as spray melt can be used without exceeding temperature limits of the matrix. (2) The cost in mills per kw hr electric, of space disposal of fission products is 4, 5, and 28 mills per kw hr for earth escape, solar orbit, and solar escape, respectively. (3) A major factor effecting cost is the earth storage time. Based on a normal operating condition design for solar escape, a storage time of more than sixty years is required to make the space disposal charge less than 10% of the bus-bar electric cost. (4) Based on a 10 year earth storage without further processing, the number of shuttle launches required would exceed one per day.

  10. Searching for Extraterrestrial Amino Acids in a Contaminated Meteorite: Amino Acid Analyses of the Canakkale L6 Chondrite

    Science.gov (United States)

    Burton, A. S.; Elsila, J. E.; Glavin, D. P.; Dworkin, J. P.; Ornek, C. Y.; Esenoglu, H. H.; Unsalan, O.; Ozturk, B.

    2016-01-01

    Amino acids can serve as important markers of cosmochemistry, as their abundances and isomeric and isotopic compositions have been found to vary predictably with changes in parent body chemistry and alteration processes. Amino acids are also of astrobiological interest because they are essential for life on Earth. Analyses of a range of meteorites, including all groups of carbonaceous chondrites, along with H, R, and LL chondrites, ureilites, and a martian shergottite, have revealed that amino acids of plausible extraterrestrial origin can be formed in and persist after a wide range of parent body conditions. However, amino acid analyses of L6 chondrites to date have not provided evidence for indigenous amino acids. In the present study, we performed amino acid analysis on larger samples of a different L6 chondite, Canakkale, to determine whether or not trace levels of indigenous amino acids could be found. The Canakkale meteor was an observed fall in late July, 1964, near Canakkale, Turkey. The meteorite samples (1.36 and 1.09 g) analyzed in this study were allocated by C. Y. Ornek, along with a soil sample (1.5 g) collected near the Canakkale recovery site.

  11. Five years of Project META - An all-sky narrow-band radio search for extraterrestrial signals

    Science.gov (United States)

    Horowitz, Paul; Sagan, Carl

    1993-01-01

    We have conducted a five-year search of the northern sky (delta between 30 and 60 deg) for narrow-band radio signals near the 1420 MHz line of neutral hydrogen, and its second harmonic, using an 8.4 x 10 exp 6 channel Fourier spectrometer of 0.05 Hz resolution and 400 kHz instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earth's rotation, which provides a characteristic changing Doppler signature for narrow-band signals of extraterrestrial origin. Among the 6 x 10 exp 13 spectral channels searched, we have found 37 candidate events exceeding the average detection threshold of 1.7 x 10 exp -23 W/sq m, none of which was detected upon reobservation. The strongest of these appear to be dominated by rare processor errors. However, the strongest signals that survive culling for terrestrial interference lie in or near the Galactic plane. We describe the search and candidate events, and set limits on the prevalence of supercivilizations transmitting Doppler-precompensated beacons at H I or its second harmonic. We conclude with recommendations for future searches, based upon these findings, and a description of our next-generation search system.

  12. Effects of the Extraterrestrial Environment on Plants: Recommendations for Future Space Experiments for the MELiSSA Higher Plant Compartment.

    Science.gov (United States)

    Wolff, Silje A; Coelho, Liz H; Karoliussen, Irene; Jost, Ann-Iren Kittang

    2014-05-05

    Due to logistical challenges, long-term human space exploration missions require a life support system capable of regenerating all the essentials for survival. Higher plants can be utilized to provide a continuous supply of fresh food, atmosphere revitalization, and clean water for humans. Plants can adapt to extreme environments on Earth, and model plants have been shown to grow and develop through a full life cycle in microgravity. However, more knowledge about the long term effects of the extraterrestrial environment on plant growth and development is necessary. The European Space Agency (ESA) has developed the Micro-Ecological Life Support System Alternative (MELiSSA) program to develop a closed regenerative life support system, based on micro-organisms and higher plant processes, with continuous recycling of resources. In this context, a literature review to analyze the impact of the space environments on higher plants, with focus on gravity levels, magnetic fields and radiation, has been performed. This communication presents a roadmap giving directions for future scientific activities within space plant cultivation. The roadmap aims to identify the research activities required before higher plants can be included in regenerative life support systems in space.

  13. Effects of the Extraterrestrial Environment on Plants: Recommendations for Future Space Experiments for the MELiSSA Higher Plant Compartment

    Directory of Open Access Journals (Sweden)

    Silje A. Wolff

    2014-05-01

    Full Text Available Due to logistical challenges, long-term human space exploration missions require a life support system capable of regenerating all the essentials for survival. Higher plants can be utilized to provide a continuous supply of fresh food, atmosphere revitalization, and clean water for humans. Plants can adapt to extreme environments on Earth, and model plants have been shown to grow and develop through a full life cycle in microgravity. However, more knowledge about the long term effects of the extraterrestrial environment on plant growth and development is necessary. The European Space Agency (ESA has developed the Micro-Ecological Life Support System Alternative (MELiSSA program to develop a closed regenerative life support system, based on micro-organisms and higher plant processes, with continuous recycling of resources. In this context, a literature review to analyze the impact of the space environments on higher plants, with focus on gravity levels, magnetic fields and radiation, has been performed. This communication presents a roadmap giving directions for future scientific activities within space plant cultivation. The roadmap aims to identify the research activities required before higher plants can be included in regenerative life support systems in space.

  14. Niche Habitats for Extra-Terrestrial Life: The Potential for Astrobiology on the Moons of Saturn and Jupiter

    Science.gov (United States)

    Battison, Leila

    2011-03-01

    Astrobiology today has a strong anticipatory focus, and efforts are concentrated on determining the factors behind the potential presence, type, and distribution of life in our solar system and beyond. The critical requirements for life: a liquid solvent, and electron acceptors and donors for metabolism, guide the search, and is a central concept to the location and extent of circumstellar habitable zones. For our own solar system, however, the search can be widened beyond this narrow band of 'earth-like' conditions, and our increasing knowledge of the capabilities of life, as well as higher resolution imaging and analysis of solar system bodies, warrants the application of a more expansive habitable niche approach. The Saturnian and Jovian satellite systems are ideal for the application of this concept, and are here used to demonstrate how a collection of system characteristics may be used to assess the potential for individual bodies to harbour life. Europa, Callisto, and Ganymede in the Jovian system, and Enceladus, Titan, Hyperion, Iapetus, and Hyperion in the Saturnian system all possess characters that could make them conducive to the origin or maintenance of life upon or within them. The possibility of some of these bodies containing extraterrestrial life is reflected in future explorative missions.

  15. A tale of two analogues: learning at a distance from the ancient greeks and maya and the problem of deciphering extraterrestrial radio transmissions

    Science.gov (United States)

    Finney, Ben; Bentley, Jerry

    The transmission of ancient Greek learning and science to medieval western Europe via the translation of Greek and Arab texts is often cited as a terrestrial example of "learning at a distance" that could occur by means of the decipherment of radio messages from advanced extraterrestrial civilizations. However, the translation between such closely related languages as Greek, Latin and Arabic and the decipherment of radio messages from an extraterrestrial civilization to the point where humans could understand them are only nominally analogous tasks. A terrestrial example of such "learning at a distance" from an ancient civilization that perhaps better prepares us for thinking about the immense task inherent in any interstellar knowledge transmission is provided by the lengthy and troubled efforts of western scholars to decipher the inscriptions left by the ancient Maya and to learn from them about this ancient civilization. Only recently, with the rejection of the ideographic fallacy that Maya glyphs symbolized ideas directly without the mediation of language and with the application of linguistic knowledge of Maya languages has it been possible to decipher the Maya inscriptions and learn from them about their science and culture. This experience suggests that without any knowledge of languages in which extraterrestrial messages might be composed, their decipherment could be most problematic. The Maya case is also relevant to the common suggestion that advanced extraterrestrials would deliberately compose messages not in their own natural languages but in artificial ones using logic, numbers, and scientific constants presumably shared among all intelligent civilizations, or at least those in their radio-communicative phases. Numbers and calendrical dating system were the first parts of the Mayan inscriptions to be translated, albeit with the aid of partial "Rosetta stones" left by the Spanish conquerors. This success served, however, to reinforce the ideographic

  16. Previsão de retornos de ações dos setores financeiro, de alimentos, industrial e de serviços, por meio de RNA e modelos ARIMA-GARCH.

    Directory of Open Access Journals (Sweden)

    Daniel Reed Bergmann

    2008-02-01

    Full Text Available O objetivo deste trabalho é realizar previsões de séries de retornos de ações de empresas dos setores financeiro, de alimentos, industrial e de serviços, utilizando redes neurais artificiais (RNA do tipo feedforward treinadas com algoritmo de Levenberg-Marquardt e modelos Arima-Garch. Selecionaram-se duas séries de cada setor, e os dados foram obtidos da economática. Para o setor financeiro, são analisadas as séries dos bancos Bradesco e Itaú, no setor de alimentos a Perdigão e a Sadia, no setor industrial a Marcopolo e a Gerdau, e no setor de serviços o Pão de Açúcar e Lojas Americanas. Verificou-se que as previsões realizadas pelas duas técnicas têm desempenhos parecidos, não revelando superioridade de nenhuma técnica.

  17. 基于ARIMA-GARCH模型对上海银行间隔夜拆放利率的实证分析%Empirical Analysis of Interbank Overnight Interest Rates in Shanghai Based on ARIMA-GARCH Model

    Institute of Scientific and Technical Information of China (English)

    夏若雯; 程宇

    2016-01-01

    通过以上海银行间隔夜拆放利率为研究对象,选取2015年1月4日至2015年12月28日的数据作为样本数据,通过Eviews软件分别建立ARMA模型和ARMA-GARCH模型对2015年12月29日至2015年12月31日的上海银行间隔夜拆放利率进行分析,以期望为金融产品的定价和投资套利提供参考.研究结果表明:ARIMA(2,2,1)-GARCH(1,0)-GED模型相较于ARIMA(2,2,1)模型很好地消除了ARCH效应,并且能够更好地对上海银行间隔夜拆放利率作出短期预测.

  18. Mass-independent isotopic compositions in terrestrial and extraterrestrial solids and their applications.

    Science.gov (United States)

    Thiemens, M H; Savarino, J; Farquhar, J; Bao, H

    2001-08-01

    In 1983, Thiemens and Heidenreich reported the first chemically produced mass-independent isotope effect. This work has been shown to have a wide range of applications, including atmospheric chemistry, solar system evolution, and chemical physics. This work has recently been reviewed (Weston, R. E. Chem. Rev. 1999, 99, 2115-2136; Thiemens, M. H. Science 1999, 283, 341-345). In this Account, observations of mass-independent isotopic compositions in terrestrial and Martian solids are reviewed. A wide range of applications, including formation and transport of aerosols in the present atmosphere, chemistry of ancient atmospheres and oceans, history and coupling of the atmosphere-surface in the Antarctic dry valleys, origin and evolution of oxygen in the Earth's earliest environment, and the chemistry of the atmosphere and surface of Mars, are discussed.

  19. Response of biological uv dosimeters to the simulated extraterrestrial uv radiation

    Science.gov (United States)

    Bérces, A.; Rontó, G.; Kerékgyártó, T.; Kovács, G.; Lammer, H.

    In the Laboratory polycrystalline uracil thin layer and bacteriophage T7 detectors have been developed for UV dosimetry on the EarthSs surface. Exponential response of the uracil polycrystal has been detected both by absorption spectroscopy and measurements of the refractive index under the influence of terrestrial solar radiation or using UV-C sources. In UV biological dosimetry the UV dose scale is additive starting at a value of zero according to the definition of CIE (Technical Report TC-6-18). The biological dose can be defined by a measured end-effect. In our dosimeters (phage T7 and uracil dosimeter) exposed to natural (terrestrial) UV radiation the proportion of pyrimidin photoproducts among the total photoproducts is smaller than 0.1 and the linear correlation between the biological and physical dose is higher than 0.9. According to the experimental data this linear relationship is often not valid. We observed that UV radiation did not only induce dimerisation but shorter wavelengths caused monomerisation of pyrimidin dimers. Performing the irradiation in oxygen free environment and using a Deuterium lamp as UV source, we could increase monomerisation against dimerisation thus the DNA-based dosimetrySs additivity rule is not fulfilled in these conditions. In this study we will demonstrate those non-linear experiments which constitute the basis of our biological experiments on the International Space Station.

  20. Using antibodies against ATPase and microarray immunoassays for the search for potential extraterrestrial life in saline environments on Mars.

    Science.gov (United States)

    Weigl, Andreas; Gruber, Claudia; Blanco-López, Yolanda; Rivas, Luis A.; Parro, Victor; Stan-Lotter, Helga

    2010-05-01

    For the search for extraterrestrial life it is proposed to use receptors such as labelled antibodies for the detection of organic biomarkers. One of these organic molecules to be tested is the universal enzyme ATP synthase which is present in highly conserved forms in all organisms on earth. Therefore it is necessary to evaluate antibodies against ATPase respectively ATP synthase and their subunits. As it is known, that there are halite deposits on Mars the experiments in this study have been carried out with regard to halophile microorganisms and saline environments. Standard F1F0 ATPase from Escherichia coli LE 392 and Bacillus megaterium as well as haloarchaeal A-ATPase from Halorubrum saccharovorum and Halobacterium salinarum NRC-1 were used. The cultivated cells, except Bacillus, were broken by passage through a French Pressure Cell. Separation of enzyme subunits was performed by polyacrylamide gel electrophoresis. Western Blotting with antisera produced in rabbit against A-ATPase subunits A (85 kD) and subunits B (60 kD) from Halorubrrum saccharovorum (1) showed positive reactions with the membrane fraction, which should be enriched with ATPase from Halorubrum saccharovorum, Halobacterium salinarum NRC-1 and Escherichia coli LE 392. Particular attention was given to the question if ATPase subunits can be detected in whole cells. Therefore whole cell preparations of all cells and spore suspensions from Geobacillus stearothermophilus were tested against the antiserum as well as against protein-A-purified antibody against A-ATPase subunit A from Halorubrum saccharovorum. A positive immuno reaction of all cell preparations with the antiserum as well as with the purified antibody was detected. The spores of Geobacillus stearothermophilus reacted positively with the antiserum against subunit A of the A-ATPase from Hrr. saccharovorum. A commercial antibody Rabbit Anti-V-ATPase subunit A polyclonal antibody from the GenScript Corporation reacted positively with

  1. Trace element and isotope geochemistry of Cretaceous-Tertiary boundary sediments: identification of extra-terrestrial and volcanic components

    Science.gov (United States)

    Margolis, S. V.; Doehne, E. F.

    1988-01-01

    Trace element and stable isotope analyses were performed on a series of sediment samples crossing the Cretaceous-Tertiary (K-T) boundary from critical sections at Aumaya and Sopelano, Spain. The aim is to possibly distinguish extraterrestrial vs. volcanic or authigenic concentration of platinum group and other elements in K-T boundary transitional sediments. These sediments also have been shown to contain evidence for step-wise extinction of several groups of marine invertebrates, associated with negative oxygen and carbon isotope excursions occurring during the last million years of the Cretaceous. These isotope excursions have been interpreted to indicate major changes in ocean thermal regime, circulation, and ecosystems that may be related to multiple events during latest Cretaceous time. Results to date on the petrographic and geochemical analyses of the Late Cretaceous and Early Paleocene sediments indicate that diagenesis has obviously affected the trace element geochemistry and stable isotope compositions at Zumaya. Mineralogical and geochemical analysis of K-T boundary sediments at Zumaya suggest that a substantial fraction of anomalous trace elements in the boundary marl are present in specific mineral phases. Platinum and nickel grains perhaps represent the first direct evidence of siderophile-rich minerals at the boundary. The presence of spinels and Ni-rich particles as inclusions in aluminosilicate spherules from Zumaya suggests an original, non-diagenetic origin for the spherules. Similar spherules from southern Spain (Caravaca), show a strong marine authigenic overprint. This research represents a new approach in trying to directly identify the sedimentary mineral components that are responsible for the trace element concentrations associated with the K-T boundary.

  2. The physical chemistry of mass-independent isotope effects and their observation in nature.

    Science.gov (United States)

    Thiemens, Mark H; Chakraborty, Subrata; Dominguez, Gerardo

    2012-01-01

    Historically, the physical chemistry of isotope effects and precise measurements in samples from nature have provided information on processes that could not have been obtained otherwise. With the discovery of a mass-independent isotopic fractionation during the formation of ozone, a new physical chemical basis for isotope effects required development. Combined theoretical and experimental developments have broadened this understanding and extended the range of chemical systems where these unique effects occur. Simultaneously, the application of mass-independent isotopic measurements to an extensive range of both terrestrial and extraterrestrial systems has furthered the understanding of events such as solar system origin and evolution and planetary atmospheric chemistry, present and past.

  3. Physical Development: Thinking Physically

    Science.gov (United States)

    Strickland, Erik

    2005-01-01

    Children grow and develop physically according to their own experiences, characteristics, and abilities. Physical development is so important and the environment should allow each child to find her space in the sunshine. This can be done by: (1) creating the right outdoor environment; (2) allowing children time to use it; (3) encouraging movement…

  4. Enantiomeric excesses induced in amino acids by ultraviolet circularly polarized light irradiation of extraterrestrial ice analogs: A possible source of asymmetry for prebiotic chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Modica, Paola; De Marcellus, Pierre; D' Hendecourt, Louis Le Sergeant [Univ. Paris-Sud, Institut d' Astrophysique Spatiale, UMR 8617, F-91405 Orsay (France); Meinert, Cornelia; Meierhenrich, Uwe J. [Univ. Nice Sophia Antipolis, Institut de Chimie de Nice, UMR 7272 CNRS, F-06108 Nice (France); Nahon, Laurent, E-mail: laurent.nahon@synchrotron-soleil.fr, E-mail: ldh@ias.u-psud.fr [Synchrotron SOLEIL, F-91192 Gif-sur-Yvette (France)

    2014-06-10

    The discovery of meteoritic amino acids with enantiomeric excesses of the L-form (ee {sub L}) has suggested that extraterrestrial organic materials may have contributed to prebiotic chemistry and directed the initial occurrence of the ee {sub L} that further led to homochirality of amino acids on Earth. A proposed mechanism for the origin of ee {sub L} in meteorites involves an asymmetric photochemistry of extraterrestrial ices by UV circularly polarized light (CPL). We have performed the asymmetric synthesis of amino acids on achiral extraterrestrial ice analogs by VUV CPL, investigating the chiral asymmetry transfer at two different evolutionary stages at which the analogs were irradiated (regular ices and/or organic residues) and at two different photon energies (6.6 and 10.2 eV). We identify 16 distinct amino acids and precisely measure the L-enantiomeric excesses using the enantioselective GC × GC-TOFMS technique in five of them: α-alanine, 2,3-diaminopropionic acid, 2-aminobutyric acid, valine, and norvaline, with values ranging from ee {sub L} = –0.20% ± 0.14% to ee {sub L} = –2.54% ± 0.28%. The sign of the induced ee {sub L} depends on the helicity and the energy of CPL, but not on the evolutionary stage of the samples, and is the same for all five considered amino acids. Our results support an astrophysical scenario in which the solar system was formed in a high-mass star-forming region where icy grains were irradiated during the protoplanetary phase by an external source of CPL of a given helicity and a dominant energy, inducing a stereo-specific photochemistry.

  5. Risk Measurement about Shanghai Interbank Offered Rate Based on GARCH Models%基于GARCH模型的上海同业拆借利率风险度量

    Institute of Scientific and Technical Information of China (English)

    房小定; 吕鹏

    2013-01-01

    In this paper, we make the overnight lending rate data of SHIBOR from October 8, 2006 to September 29, 2012 as an object for our study, useing VaR model to measure the Shanghai Interbank Offered Rate.We find GARCH (1,2)-GED distribution could characterize SHIBOR logarithmic distribution of daily return series betterly, in considering asymmetric rates tested, the EGARCH (1,2)-GED distribution can best portray SHIBOR logarithmic the distribution of daily return series and the estimated value of the asymmetric term is greater than zero and significant, indicating the presence of"anti-leverage effect", that is the impact of a negative impact for the interbank interest rate markets will cause greater volatility. Finally, we use the GARCH (1,2)-GED and EGARCH (1,2)-GED, respectively 95% and 99% confidence level to get VaR values about Shanghai interbank interest rate. Both models have passed the test back to test, and the models can be used to measure VaR values about the Shanghai interbank offered rate market.%  本文采用2006年10月8日至2012年9月29日的上海银行间同业拆借利率(SHIBOR)中的隔夜拆借利率数据作为研究对象,利用VaR模型对上海同业拆借利率进行度量,得出GARCH(1,2)-GED分布较好地刻画SHIBOR对数日收益率序列的分布,在考虑利率非对称性进行检验时,得出EGARCH(1,2)-GED分布最能刻画SHIBOR对数日收益率序列的分布,且非对称项的估计值为大于零且显著,表明存在“反杠杆效应”,即正的冲击比负的冲击会引起同业拆借利率市场更大的波动性。最后对GARCH(1,2)-GED与EGARCH(1,2)-GED分别在95%与99%的置信水平下得出上海同业拆借利率的VaR值。这两个模型都通过了模型回测检验,可用于测算上海银行间同业拆借利率市场对数收益率的风险价值。

  6. Research of Information Transmission Mode for International Securities Markets:Based on Vector GARCH Model%基于向量GARCH模型的国际证券市场波动溢出研究

    Institute of Scientific and Technical Information of China (English)

    王鹰翔; 张鲁欣

    2011-01-01

    IBased on vector GARCH model,this paper studies the mean and volatility spillover effect of international securities markets,and some advices for the development of Chinese stock market are given.The results show that one-way mean spillover effect does not exist in international securities markets.There is a two-way market volatility spillover effect between the United States stock market and Shanghai A-share market.The existence of volatility spillover effect in above markets indicates that Chinese capital market and the United States capital market are becoming increasingly integrated.%以向量GARCH模型为基础,研究了国际证券市场中上海A股市场、香港市场和美国市场的均值溢出效应和波动溢出效应,并且给出了中国证券市场发展的政策建议。研究结果表明,三个市场均不存在单向的均值溢出效应,上海A股市场和美国证券市场存在双向的波动溢出效应。上海A股市场和美国证券市场存在波动溢出效应,反映了中国资本市场和美国资本市场融合程度的加强。

  7. 国内外煤炭价格波动特征分析——基于GARCH模型%Analysis on Characteristics of Coal Price′s Volatility:Based on GARCH Model

    Institute of Scientific and Technical Information of China (English)

    李晓明; 万昆; 柳瑞禹

    2012-01-01

    This paper uses the time series date of Australia BJ steam coal price and Datong quality mix coal in Qinhuangdao market(6000 kcal) price during 2005-2011 and GARCH(general autoregressive conditional heteroskedasticity model) model to study empirically the price volatility of Australia BJ steam coal price and Datong quality mix coal in Qinhuangdao market(6000 kcal) price.The result shows that Australia BJ steam coal price and Datong quality mix coal in Qinhuangdao market(6000 kcal) price present the same characteristics which are significant GARCH effect and volatility clustering.The volatility decay slowly and it does not have a significant asymmetry.Finally,it also puts forward the corresponding countermeasures and suggestions.%利用2005—2011年的澳洲BJ动力煤价格和秦皇岛大同优混煤(〉6000大卡)价格的时间序列数据,采用GARCH模型分析方法,实证检验了澳洲BJ动力煤价格和秦皇岛大同优混煤(〉6000大卡)价格的波动性特征。研究结果表明,澳洲BJ动力煤价格和秦皇岛大同优混煤(〉6000大卡)价格表现出相同的市场特性,具有显著的GARCH效应与波动聚集性,波动衰减缓慢,不具有显著的非对称性波动。最后提出了相应的对策与建议。

  8. 基于Markov-switching-GARCH模型的股指期货与现货市场的相关性影响分析%Correlation Analysis of the Stock Index Futures and Spot Markets Based on the Markov-switching-GARCH Model

    Institute of Scientific and Technical Information of China (English)

    陈静思; 叶德磊; 顾京

    2014-01-01

    通过能识别和捕捉内生性波动状态的Markov-switching-GARCH模型来改进含有虚拟变量的GARCH模型中不能很好地刻画外生性结构变化的不足,选取沪深300股指期货作为参照对现货市场的波动性影响进行分析。实证研究显示:该模型能够较好地刻画现货市场收益率的结构变化,反映了股指期货的推出不仅没有加剧现货市场的波动,反而减弱了现货市场的波动程度,使得市场流入的有效信息得到增强,市场运行效率整体得到明显提升。%Markov-switching-GARCH model,which can identify and capture the endoge-nous fluctuations,is used to make up the shortage of GARCH model with virtual variable which cannot well depict the exogenous structural change. The CSI 300 stock index futures is taken as reference to analyze the volatility impact of spot markets. The empirical study shows that Markov-switching-GARCH model can well describe the structural changes of market profitability of spot markets,supporting that the index futures weakened the volatility degree of spot markets instead of exacerbating it,which enhances the effective information flow into the market as well as the overall operation efficiency of the market.

  9. A New Method and Mass-Spectrometric Instrument for Extraterrestrial Microbial Life Detection Using the Elemental Composition Analyses of Martian Regolith and Permafrost/Ice

    Science.gov (United States)

    Managadze, G. G.; Safronova, A. A.; Luchnikov, K. A.; Vorobyova, E. A.; Duxbury, N. S.; Wurz, P.; Managadze, N. G.; Chumikov, A. E.; Khamizov, R. Kh.

    2017-05-01

    We propose a new technique for the detection of microorganisms by elemental composition analyses of a sample extracted from regolith, permafrost, and ice of extraterrestrial bodies. We also describe the design of the ABIMAS instrument, which consists of the onboard time-of-flight laser mass-reflectron (TOF LMR) and the sample preparation unit (SPU) for biomass extraction. This instrument was initially approved to fly on board the ExoMars 2020 lander mission. The instrument can be used to analyze the elemental composition of possible extraterrestrial microbial communities and compare it to that of terrestrial microorganisms. We have conducted numerous laboratory studies to confirm the possibility of biomass identification via the following biomarkers: P/S and Ca/K ratios, and C and N abundances. We underline that only the combination of these factors will allow one to discriminate microbial samples from geological ones. Our technique has been tested experimentally in numerous laboratory trials on cultures of microorganisms and polar permafrost samples as terrestrial analogues for martian polar soils. We discuss various methods of extracting microorganisms and sample preparation. The developed technique can be used to search for and identify microorganisms in different martian samples and in the subsurface of other planets, satellites, comets, and asteroids—in particular, Europa, Ganymede, and Enceladus.

  10. Studies on different geophysical and extra-terrestrial events within the Earth-ionosphere cavity in terms of ULF/ELF/VLF radio waves

    Science.gov (United States)

    Sanfui, Minu; Haldar, D. K.; Biswas, Debasish

    2016-10-01

    The space between the two spherical conducting shells, Earth surface and the lower boundary of the ionosphere, behaves as a spherical cavity in which some electromagnetic signals can propagate a long distance and is called Earth-ionosphere waveguide. Through this waveguide ultra low frequency (ULF), extremely low frequency (ELF) and very low frequency (VLF) signals can propagate efficiently with low attenuation. Resonances which occur for ELF waves due to round-the-world propagation interfering with 2n π phase difference are called Schumann resonances. Lightnings are the main sources of energy continuously producing these electromagnetic radiations from the troposphere. Some fixed frequency signals are also transmitted through the waveguide from different stations for navigation purposes. The intensity and phase of these signals at a particular position depend on the waveguide characteristics which are highly influenced by different natural events. Thus the signatures of different geophysical and extra-terrestrial events may be investigated by studying these signals through proper monitoring of the time series data using suitable techniques. In this article, we provide a review on ULF, ELF and VLF signals within the waveguide in terms of different geophysical and extra-terrestrial events like lightning, earthquakes, Leonid meteor shower, solar flares, solar eclipse, geomagnetic storms, and TLEs etc.

  11. Terrestrial and extraterrestrial fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Heymann, D.; Jenneskens, L.W.; Jehlicka, J; Koper, C.; Vlietstra, E. [Rice Univ, Houston, TX (United States). Dept. of Earth Science

    2003-07-01

    This paper reviews reports of occurrences of fullerenes in circumstellar media, interstellar media, meteorites, interplanetary dust particles (IDPs), lunar rocks, hard terrestrial rocks from Shunga (Russia), Sudbury (Canada) and Mitov (Czech Republic), coal, terrestrial sediments from the Cretaceous-Tertiary-Boundary and Pennian-Triassic-Boundary, fulgurite, ink sticks, dinosaur eggs, and a tree char. The occurrences are discussed in the context of known and postulated processes of fullerene formation, including the suggestion that some natural fullerenes might have formed from biological (algal) remains.

  12. 基于VAR-DCC-GARCH模型的国内外有色金属商品价格联动分析%Price linkage between Chinese and international nonferrous metals commodity markets based on VAR-DCC-GARCH models

    Institute of Scientific and Technical Information of China (English)

    岳意定; 刘笃池; 徐珊

    2015-01-01

    Using VAR-DCC-GARCH model, the literature on commodity price was extended by exploring the co-movement between Chinese nonferrous metal prices and global nonferrous metal prices represented by the nonferrous metal prices from London Metal Exchange (LME). The results show that LME nonferrous metals prices still have a greater impact on Chinese nonferrous metals prices. However, the impact of Chinese nonferrous metals prices on LME nonferrous metals prices is still weak except for lead price. The co-movement of nonferrous metal prices between LME and China presents hysteretic nature, and it lasts for 7−8 trading days. Furthermore, the co-movement between LME nonferrous metals prices and Chinese nonferrous metals prices has the characteristics of time-varying, and the correlation of lead prices between LME and China is the more stable than all other nonferrous metals prices.%运用VAR-DCC-GARCH模型,研究LME金属价格与中国金属价格间的联动效应及其动态相关性。结果表明:LME金属价格依然对中国金属价格有着较大的影响,而中国除了铅价外,其余金属价格对LME金属价格的影响还很微弱;中国铜、铅、锌价格与LME价格间均存在正向的联动性;LME金属价格与中国金属价格之间的联动性在反应时间上存在滞后性,滞后期在7到8个交易日左右;LME金属价格和中国金属价格间的互动影响关系存在时变性,其中,LME铅价与中国铅价间的相互关联最稳定。

  13. A Study of the Design of Stock Index Fluctuation Stress Testing Scenario: Based on ARMA-GARCH Model%基于ARMA-GARCH模型的股指波动压力测试情景设计研究

    Institute of Scientific and Technical Information of China (English)

    侯外林

    2011-01-01

    Aiming at such characteristics as the heteroscedasticity, sharp peak and thick tail, serial autocorrelation and so on during some time series of stock index returns, this paper combines the ARMA model with GARCH model to set up a regression model, so as to estimate the VaR value of the annual return rate of the related stock index, which can effectively predict the stock volatility and the accompanying probability under the similar market conditions. Therefore, during the stress testing practices of the securities companies, reasonably designed stress testing scenarios of downward stock index based on accompanied probability can further improve the scientificalness of the design of stress testing scenarios and enhance the practical guidance of the stress testing results. At the same time, the idea of this paper can be applied to the empirical analysis of financial time series with abundant historical data of interest rates, exchange rates, market trading volume etc., so as to guide the design of stress test scenarios, such as bond market fluctuations, foreign exchange fluctuations and fluctuations in market trading volumes.%针对股指收益率时间序列某期间的异方差、尖峰厚尾以及序列自相关等特性,将ARMA模型与GARCH模型相结合,回归建模测算相关股指年度收益率VaR值,可以有效预测类似市场条件下股指的波动以及相伴概率。因此,在证券公司压力测试实践中,基于相伴概率合理设计股指下跌的压力测试情景,可以进一步提高压力测试情景设计的科学性,增强压力测试结果的现实指导意义。同时,可以将本文研究思路推广应用于利率、汇率、市场交易量等历史数据较充分的金融时间序列的实证分析,借以指导债市波动、汇市波动以及市场交易量波动等压力测试情景的设计工作。

  14. Physical Allergy

    Science.gov (United States)

    ... Appears Safe in Study Additional Content Medical News Physical Allergy By Peter J. Delves, PhD, Professor of ... Disorders Exercise-Induced Allergic Reactions Food Allergy Mastocytosis Physical Allergy Seasonal Allergies Year-Round Allergies A physical ...

  15. Sports physical

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000673.htm Sports physical To use the sharing features on this page, ... routine checkups. Why do you Need a Sports Physical? The sports physical is done to: Find out ...

  16. Crossed beam investigation of elementary reactions relevant to the formation of polycyclic aromatic hydrocarbon (PAH)-like molecules in extraterrestrial environments

    Science.gov (United States)

    Kaiser, R. I.; Asvany, O.; Lee, Y. T.

    2000-04-01

    The reactions of ground state carbon atoms, C( 3P j), with benzene, C 6H 6, and phenyl radicals, C 6H 5, with methylacetylene, CH 3CCH, were investigated in crossed beam experiments at collision energies of 21.8 and 140 kJ mol -1 to investigate elementary reactions relevant to the formation and chemistry of polycyclic aromatic hydrocarbons (PAHs) in extraterrestrial environments. The C( 3P j) reaction proceeds via complex formation and gives a cyclic, seven-membered C 7H 5 doublet radical plus atomic hydrogen. This pathway has neither an entrance nor exit barrier, and is exothermic. Together with the experimental verification of the carbon versus hydrogen exchange under single collision conditions, the findings have an important impact on the chemistry of aromatic molecules in interstellar clouds and outflow of carbon stars. Even in the coldest molecular clouds ( T=10 K), the benzene molecule can be destroyed upon reaction with carbon atoms, whereas they are resistant toward an attack of oxygen and nitrogen atoms. Since the aromatic benzene unit is ubiquitous in extraterrestrial, PAH-like material, our results suggest that PAHs might react with carbon atoms as well. On the other side, the reaction of C 6H 5 radicals with methylacetylene to form phenylmethylacetylene is direct. Since an entrance barrier inhibits the reaction in cold molecular clouds and in the atmospheres of hydrocarbon rich planets like Jupiter and Saturn and satellites such as Titan, this reaction is expected to play a role in PAH synthesis only in high temperature interstellar environments, such as circumstellar outflows of carbon stars.

  17. Nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Sang, David (Bishop Luffa Comprehensive School, Chichester (UK))

    1990-01-01

    Nuclear Physics covers the aspects of radioactivity and nuclear physics dealt with in the syllabuses of all the A-level examination boards; in particular, it provides detailed coverage of the Joint Matriculation Board option in nuclear physics. It deals with the discovery of the atomic nucleus, the physics of nuclear processes, and nuclear technology. (author).

  18. Comprehensive Modeling of Superficial Dust Removal via Electrostatic and Dielectrophoretic Forces in Extraterres-trial Exploration Mission

    Science.gov (United States)

    Dominguez, Jesus A.; Phillips, James R. III; Mackey, Paul J.; Hogue, Michael D.; Johansen, Michael R.; Cox, Rachel E.; Calle, Carlos I.

    2017-01-01

    The Electrostatics and Surface Physics Laboratory (ESPL) at NASA Kennedy Space Center has developed a dust mitigation technology that uses electrostatic and dielectrophoretic (DEP) forces to disperse and remove the dust already deposited on surfaces preventing the accumulation of dust particles approaching or already deposited on those surfaces.

  19. Statistical Physics

    CERN Document Server

    Mandl, Franz

    1988-01-01

    The Manchester Physics Series General Editors: D. J. Sandiford; F. Mandl; A. C. Phillips Department of Physics and Astronomy, University of Manchester Properties of Matter B. H. Flowers and E. Mendoza Optics Second Edition F. G. Smith and J. H. Thomson Statistical Physics Second Edition E. Mandl Electromagnetism Second Edition I. S. Grant and W. R. Phillips Statistics R. J. Barlow Solid State Physics Second Edition J. R. Hook and H. E. Hall Quantum Mechanics F. Mandl Particle Physics Second Edition B. R. Martin and G. Shaw The Physics of Stars Second Edition A. C. Phillips Computing for Scient

  20. Particle physics

    CERN Document Server

    Martin, Brian R

    2017-01-01

    An accessible and carefully structured introduction to Particle Physics, including important coverage of the Higgs Boson and recent progress in neutrino physics. Fourth edition of this successful title in the Manchester Physics series. Includes information on recent key discoveries including : An account of the discovery of exotic hadrons, beyond the simple quark model; Expanded treatments of neutrino physics and CP violation in B-decays; An updated account of ‘physics beyond the standard model’, including the interaction of particle physics with cosmology; Additional problems in all chapters, with solutions to selected problems available on the book’s website; Advanced material appears in optional starred sections.