A taxonomic review of the Pterophoridae (Lepidoptera) from Argentina and Chile
Gielis, C.
1991-01-01
The known species of Pterophoridae occurring in Argentina and Chile are reviewed. Nearly all the available type specimens of species occurring in the area have been examined and five new synonyms have been established. Some primary types are considered to be lost. In this paper three new genera and
1992-05-01
The background notes on Chile provide a statistical summary of the population, geography, government, and the economy, and more descriptive text on the history, population, government, economy, defense, and foreign relations. In brief, Chile has 13.3 million Spanish Indian (Mestizos), European, and Indian inhabitants and an annual growth rate of 1.6%. 96% are literate. Infant mortality is 18/1000. 34% of the population are involved in industry and commerce, 30% in services, 19% in agriculture and forestry and fishing, 7% in construction, and 2% in mining. The major city is Santiago. The government, which gained independence in 1810, is a republic with executive, legislative, and judicial branches. There are 12 regions. There are 6 major political parties. Suffrage is universal at 18 years. Gross domestic product (GDP) is $29.2 billion. The annual growth rate is 5% and inflation is 19%. Copper, timber, fish, iron ore, nitrates, precious metals, and molybdenum are its natural resources. Agricultural products are 9% of GDP and include wheat, potatoes, corn, sugar beets, onions, beans, fruits, and livestock. Industry is 21% of GDP and includes mineral refining, metal manufacturing, food and fish processing, paper and wood products, and finished textiles. $8.3 billion is the value of exports and $7 billion of imports. Export markets are in Japan, the US, Germany, Brazil, and the United Kingdom. Chile received $3.5 billion in economic aid between 1949-85, but little in recent years. 83% live in urban centers, principally around Santiago. Congressional representation is made on the basis of elections by a unique binomial majority system. Principal government officials are identified. Chile has a diversified free market economy and is almost self-sufficient in food production. The US is a primary trading partner. 49% of Chile's exports are minerals. Chile maintains diplomatic relations with 70 countries, however, relations are strained with Argentina and Bolivia. Relations
1988-09-01
Chile is a long (2650 miles), narrow (250 miles at widest point) country sandwiched between the Andes mountains and the Pacific. The northern desert is rich in copper and nitrates; the temperate middle region is agricultural and supports the major cities, including Santiago, the capital, and the port of Valparaiso; and the southern region is a cold and damp area of forests, grasslands, lakes, and fjords. The country is divided into 12 administrative regions. Chile's population of 12.5 million are mainly of Spanish or Indian descent or mestizos. Literacy is 92.3%, and the national language is Spanish. Infant mortality is 18.1/1000, and life expectancy is 68.2 years. 82% of the people are urban, and most are Roman Catholics. Chile was settled by the Spanish in 1541 and attached to the Viceroyalty of Peru. Independence was won in 1818 under the leadership of Bernardo O'Higgins. In the 1880s Chile extended its sovereignty over the Strait of Magellan in the south and areas of southern Peru and Bolivia in the north. An officially parliamentary government, elected by universal suffrage, drifted into oligarchy and finally into a military dictatorship under Carlos Ibanez in 1924. Constitutional government was restored in 1932. The Christian Democratic government of Eduardo Frei (1964-70) inaugurated major reforms, including land redistribution, education, and far-reaching social and economic policies. A Marxist government under Salvador Allende lasted from 1970 to 1973 when the present military government of General Pinochet Ugarte took power, overthrew Allende, abolished the Congress, and banned political parties. It has moved the country in the direction of a free market economy but at the cost of systematic violations of human rights. A new constitution was promulgated in 1981, and congressional elections have been scheduled for October, 1989. A "National Accord for Transition to Full Democracy" was mediated by the Catholic Church in 1985. The social reforms of the
1986-04-01
In 1985, Chile's population stood at 12 million, with an annual growth rate of 1.7%. 1984's infant mortality rate was 20/1000 live births and life expectancy was 67 years. The literacy rate was 94%. Of the work force of 3,841,000 in 1985, 15.9% were engaged in agriculture, forestry, and fishing; 31.3% were employed in industry and commerce; 38.6% were in the service sector; 8.7% worked in mining; and 4.4% were employed in construction. Chile's military junta is scheduled to be replaced by an elected legislature in 1990. The GDP was US $19.2 billion in 1984, with an annual real growth rate of 6.3%, and per capita GDP stood at US$1590. Inflation averages 23%. Industry comprises 21% of the GDP. Longterm prospects for the Chilean economy are influenced by a high debt service ratio, very low domestic savings and investment, the prospect of little or no increase in copper prices, and continuing problems in the domestic financial sector. In 1985-88, under the International Monetary Fund macroeconomic program, Chile will strive for moderate economic growth while managing its external debt servicing burden. PMID:12178144
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T. HEATH-OGDEN
2001-09-01
Full Text Available The adult, larva, and pupa of Afdera jimenae Ogden & Parra sp. nov. are described and illustrated. Larvae live in leaf litter throughout all instars and are generalists feeding upon the fallen leaves of a number of different plant species of sclerophyllous forests. Comments on morphological details and bionomics of this species are given. This is the second species of Afdera know for ChileSe describe e ilustra el adulto, larva y pupa de Afdera jimenae Ogden & Parra sp. nov. Los diferentes estados larvarios se encuentran en la hojarasca del bosque esclerófilo de la Península de Hualpén, alimentándose de hojas en descomposición de diferentes especies vegetales. Se entregan comentarios sobre detalles morfológicos y bionómicos de la especie. Esta es la segunda especie de Afdera descrita para Chile
Solanum section Petota (Solanaceae), which includes the cultivated potato (Solanum tuberosum) and its wild relatives, contains over 150 wild species distributed from the southwestern U.S.A. (38°N) to central Argentina and adjacent Chile (41°S). This catalog includes all species from the Southern Con...
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Sylvia Sáez
2010-01-01
Full Text Available Se presenta una serie de claves para el reconocimiento dentario de diferentes taxa del Superorden Squalomorphi de Chile. Se seleccionaron características dentarias externas que permitan obtener una observación más expedita que conduzcan a un estudio más acabado, de la diagnosis de los diferentes taxa constituyentes de este grupo de peces, haciéndolas extensibles para estudios de piezas dentales fósiles.A series of taxonomic dental keys is presented for the Chilean taxa of the Superorder Squalomorphi. External dental characteristics were selected for easier observation, leading to more thorough studies. This allows diagnoses of the different taxa comprising this group of fishes and, moreover, can be extended to studies of fossil teeth.
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Sylvia Sáez
2012-07-01
Full Text Available Se presenta claves taxonómicas basadas en características morfológicas dentarias externas e internas, que permiten el reconocimiento de cada orden, familia y género de los batoídeos conocidos en Chile. En algunos casos, como en las familias Rhinobatidae, Torpedinidae, Narcinidae, Myliobatidae, Mobulidae, Dasyatidae y Urotrygonidae, las claves permiten el reconocimiento específico pero, en otros casos, sólo se puede discriminar hasta género, dadas las limitaciones impuestas por los conocimientos existentes. Estas claves son una herramienta complementaria a la diagnosis de rayas y están orientadas al reconocimiento de fragmentos dentales, hallazgos paleontológicos de dientes así como para las piezas dentales asociadas con la mandíbula. De esta manera, se entrega un apoyo taxonómico nuevo con características dentales diferentes a las consideradas actualmente para este superorden.A series of keys with external and internal dental morphologic features for the identification of each order, family and genus of rays and skates of the batoids known in Chile, are presented. In the case of families Rhinobatidae, Torpedinidae, Narcinidae, Myliobatidae, Mobulidae, Dasyatidae and Urotrygonidae, an identification at the species level is possible. In other cases, due to limitations imposed by the existing knowledge, only discrimination up to genus is allowed. These keys are a complementary tool for the diagnosis of rays suitable for the identification of dental fragments, paleontological discoveries of teeth as well as for jaw teeth. This tool offers a novel taxonomic support, which includes dental features different from those considered nowadays for this superorder.
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DAVID VELIZ
2000-12-01
Full Text Available Este estudio describe la diversidad, y la distribución latitudinal y batimétrica de los caracoles de la Familia Trochidae en el norte de Chile, mediante muestreos intermareales y submareales someros, realizados entre 1996 y 1999 entre Arica (18º S y Los Vilos (31º S, y de muestras de profundidad provenientes de la pesca de arrastre del camarón nylon, Heterocarpus reedi. En el norte de Chile, la Familia Trochidae está representada por cuatro géneros: Tegula y Diloma de distribución intermareal y submareal somero hasta los 20 m de profundidad, y Bathybembix y Calliostoma presentes en profundidades superiores a los 200 m. El género Tegula tiene seis especies (T. quadricostata, T. luctuosa, T. ignota, T. atra, T. tridentata y T. euryomphala distribuídas en sustratos rocosos intermareales y submarales someros. El género Diloma está representado por una especie, D. nigerrima, de distribución intermareal hasta pocos metros de profundidad. El género Calliostoma tiene dos especies C. chilena y C. delli, las que se distribuyen entre 200 y 750 m de profundidad. Finalmente, el género Bathybembix está representado por B. humboldti y B. macdonaldi distribuídas entre 200 y 1480 m de profundidad. Esta segregación batimétrica parece estar relacionada a las estrategias alimentarias de cada uno de los géneros de la familia Trochidae. Diloma y Tegula son herbívoros, las especies del género Bathybembix son alimentadoras de depósito y las de Calliostoma son carnívorasThis study reveals the diversity, and the bathimetric and latitudinal distribution of the snails of the Trochidae family members in northern Chile, throughout the analysis of all Trochidae gastropods entailed in intertidal and subtidal (from the `camarón naylon' fishery samples collected during 1996 and 1999 between Arica (ca 18º S and Los Vilos (ca 31º S. The Trochidae family in northern Chile have four genus: Tegula and Diloma that are distributed on intertidal and shallow
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JOSÉ M. GUERRA-GARCÍA
2001-12-01
difficult due to the high degree of intra-specific morphological variability and the fact that literature and specimens from Museums are not easily located. The objective of the present study was to provide the taxonomical tools to identify the most common caprellid species from northern-central Chile. Several habitats were examined (buoys, boulders, algal/seagrass beds and six caprellid species were found: Caprellina longicollis (Nicolet, 1849, Caprella equilibra Say, 1818, C. scaura Templeton, 1836, C. verrucosa Boeck, 1871; Deutella venenosa Mayer, 1890 and Paracaprella pusilla Mayer, 1890. Caprella scaura, C. verrucosa and D. venenosa were most abundant among algae, hydrozoans and bryozoans growing on buoys. Caprella equilibra, also present on buoys, was most abundant underneath boulders in exposed rocky intertidal zones, where additionally D. venenosa and P. pusilla were found. Caprella scaura was dominant in plant beds above sandy subtidal bottom, especially among the alga Gracilaria chilensis and the seagrass Heterozostera tasmanica, where it occurred together with Caprellina longicollis. Paracaprella pusilla represents a new citation for the pacific coasts of S-America, being a new record for Chile. The species D. venenosa, which was recorded for the first time since the original description by Mayer in the year 1890, is considered an endemic species from the central coast of Chile
Balov, Nikolay H.
2008-01-01
We introduce and study covariance fields of distributions on a Riemannian manifold. At each point on the manifold, covariance is defined to be a symmetric and positive definite (2,0)-tensor. Its product with the metric tensor specifies a linear operator on the respected tangent space. Collectively, these operators form a covariance operator field. We show that, in most circumstances, covariance fields are continuous. We also solve the inverse problem: recovering distribution from a covariance...
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Frieder Kleefeld
2013-01-01
Full Text Available According to some generalized correspondence principle the classical limit of a non-Hermitian quantum theory describing quantum degrees of freedom is expected to be the well known classical mechanics of classical degrees of freedom in the complex phase space, i.e., some phase space spanned by complex-valued space and momentum coordinates. As special relativity was developed by Einstein merely for real-valued space-time and four-momentum, we will try to understand how special relativity and covariance can be extended to complex-valued space-time and four-momentum. Our considerations will lead us not only to some unconventional derivation of Lorentz transformations for complex-valued velocities, but also to the non-Hermitian Klein-Gordon and Dirac equations, which are to lay the foundations of a non-Hermitian quantum theory.
Estimating Cosmological Parameter Covariance
Taylor, Andy
2014-01-01
We investigate the bias and error in estimates of the cosmological parameter covariance matrix, due to sampling or modelling the data covariance matrix, for likelihood width and peak scatter estimators. We show that these estimators do not coincide unless the data covariance is exactly known. For sampled data covariances, with Gaussian distributed data and parameters, the parameter covariance matrix estimated from the width of the likelihood has a Wishart distribution, from which we derive the mean and covariance. This mean is biased and we propose an unbiased estimator of the parameter covariance matrix. Comparing our analytic results to a numerical Wishart sampler of the data covariance matrix we find excellent agreement. An accurate ansatz for the mean parameter covariance for the peak scatter estimator is found, and we fit its covariance to our numerical analysis. The mean is again biased and we propose an unbiased estimator for the peak parameter covariance. For sampled data covariances the width estimat...
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SERGIO ROIG-JUÑENT
2001-09-01
Full Text Available Carabidae constituye dentro de los coléopteros chilenos, la cuarta familia en importancia por su cantidad de especies. El presente trabajo incluye una breve compilación acerca de la historia de la familia y de las primeras expediciones realizadas en Chile. También se realizan comparaciones de la diversidad de carábidos chilenos con respecto a otros países y el Neotrópico. Para Chile, se conocen 21 tribus, con 95 géneros y 365 especies, que representan el 38,8, 28,8 y 7,9 % de la fauna del Neotrópico, respectivamente. Chile posee un bajo número de tribus comparado con otros países, sin embargo, constituye un área importante por la presencia de seis tribus relictuales, principalmente pangeicas o gondwánicas. Chile posee 18 géneros endémicos (18,5 % de su fauna de Carabidae, 28 cuya distribución está restringida a Chile y Argentina y seis restringidos a Chile, Argentina y Uruguay. La cantidad de especies presentes en Chile es inferior a la que poseen otros países de América del Sur, pero la cantidad de especies endémicas es muy alta (204 y representa el 55,8 % de su fauna de carábidos. El alto grado de endemismo que posee Chile con respecto a otros países de América del Sur puede deberse a su condición de aislamiento, siendo las barreras más importantes la región desértica del norte y la cordillera de Los Andes. Este hecho también se vislumbra por la ausencia de importantes tribus neotropicales como Galeritini, Scaritini y Brachinini. También se incluyen en este trabajo claves para la identificación de todas las tribus y géneros presentes en Chile, como así también una breve descripción acerca de la diversidad y ambientes en los que se encuentra cada géneroThe family Carabidae is the fourth largest Coleoptera family in Chile. The present work includes a brief compilation on the taxonomic history of the family and the first expeditions to Chile. In addition, knowledge of carabid diversity in Chile is compared with
Hepner, T. E.; Meyers, J. F. (Inventor)
1985-01-01
A laser velocimeter covariance processor which calculates the auto covariance and cross covariance functions for a turbulent flow field based on Poisson sampled measurements in time from a laser velocimeter is described. The device will process a block of data that is up to 4096 data points in length and return a 512 point covariance function with 48-bit resolution along with a 512 point histogram of the interarrival times which is used to normalize the covariance function. The device is designed to interface and be controlled by a minicomputer from which the data is received and the results returned. A typical 4096 point computation takes approximately 1.5 seconds to receive the data, compute the covariance function, and return the results to the computer.
Székely, Gábor J.; Rizzo, Maria L.
2009-01-01
Distance correlation is a new class of multivariate dependence coefficients applicable to random vectors of arbitrary and not necessarily equal dimension. Distance covariance and distance correlation are analogous to product-moment covariance and correlation, but generalize and extend these classical bivariate measures of dependence. Distance correlation characterizes independence: it is zero if and only if the random vectors are independent. The notion of covariance with respect to a stochas...
Registro nuevo de Amphipyrinae en Chile A new record of Amphipyrinae from Chile
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Tania S. Olivares
2006-12-01
Full Text Available Se registra por primera vez en Chile la especie Agrotisia subhyalina Hampson, entre las latitudes 18° 29' S 70° 20' O hasta 29° 54' S 71° 16' O (I-IV regiones en Chile. Se redescriben los genitales del macho y de la hembra y se presentan algunos aspectos taxonómicos de la especie.The species Agrotisia subhyalina Hampson is recorded for the first time from Chile (18° 29' S 70° 20' W to 29° 54' S 71° 16' W, I to IV Chilean regions. Redescriptions of male and female are presented, along with some taxonomic aspects of the species.
Taxonomic abstraction in psychobiology.
Evans, S H; Chafetz, M D; Gage, F H
1984-10-01
If a body of knowledge in a scientific discipline is to be extended beyond empirical observation and into the realm of laws and principles, one of the fundamental requirements is a taxonomy which supports the systematic integration of observations. Psychobiology benefits from taxonomies provided by biology and chemistry, which include not only object oriented taxonomies such as species or chemical elements, but also process oriented taxonomies, such as oxidation, metabolism, phototaxis, or predation. Psychobiology has yet to provide equivalent taxonomies for its behavioral observations, although the common use of terms such as fear, anger, arousal, stress, and memory might lead one to suppose that these are based on a well established taxonomy of behavioral measures. In this report the logical and quantitative requirements for treating behavioral measures in terms of taxonomic classes are reviewed. A sample of studies representing recent research in psychobiology was examined to assess interest in such a taxonomy and to identify elements of current practice which might contribute to its development. Recent practice displays some evidence of interest in behavioral classes, in choice of language, and in frequent use of multiple dependent measures. Multivariate methods, which might elicit from such data evidence contributing to the development of a taxonomy, are rarely used. Recommendations are given on some appropriate analytic methods for data resulting from current practice and for new exploratory paradigms which could aim directly at the establishment of taxonomic classes for behaviors.
Covariant Noncommutative Field Theory
International Nuclear Information System (INIS)
The covariant approach to noncommutative field and gauge theories is revisited. In the process the formalism is applied to field theories invariant under diffeomorphisms. Local differentiable forms are defined in this context. The lagrangian and hamiltonian formalism is consistently introduced
Frasinski, Leszek J.
2016-08-01
Recent technological advances in the generation of intense femtosecond pulses have made covariance mapping an attractive analytical technique. The laser pulses available are so intense that often thousands of ionisation and Coulomb explosion events will occur within each pulse. To understand the physics of these processes the photoelectrons and photoions need to be correlated, and covariance mapping is well suited for operating at the high counting rates of these laser sources. Partial covariance is particularly useful in experiments with x-ray free electron lasers, because it is capable of suppressing pulse fluctuation effects. A variety of covariance mapping methods is described: simple, partial (single- and multi-parameter), sliced, contingent and multi-dimensional. The relationship to coincidence techniques is discussed. Covariance mapping has been used in many areas of science and technology: inner-shell excitation and Auger decay, multiphoton and multielectron ionisation, time-of-flight and angle-resolved spectrometry, infrared spectroscopy, nuclear magnetic resonance imaging, stimulated Raman scattering, directional gamma ray sensing, welding diagnostics and brain connectivity studies (connectomics). This review gives practical advice for implementing the technique and interpreting the results, including its limitations and instrumental constraints. It also summarises recent theoretical studies, highlights unsolved problems and outlines a personal view on the most promising research directions.
Covariant canonical quantization
Energy Technology Data Exchange (ETDEWEB)
Hippel, G.M. von [University of Regina, Department of Physics, Regina, Saskatchewan (Canada); Wohlfarth, M.N.R. [Universitaet Hamburg, Institut fuer Theoretische Physik, Hamburg (Germany)
2006-09-15
We present a manifestly covariant quantization procedure based on the de Donder-Weyl Hamiltonian formulation of classical field theory. This procedure agrees with conventional canonical quantization only if the parameter space is d=1 dimensional time. In d>1 quantization requires a fundamental length scale, and any bosonic field generates a spinorial wave function, leading to the purely quantum-theoretical emergence of spinors as a byproduct. We provide a probabilistic interpretation of the wave functions for the fields, and we apply the formalism to a number of simple examples. These show that covariant canonical quantization produces both the Klein-Gordon and the Dirac equation, while also predicting the existence of discrete towers of identically charged fermions with different masses. Covariant canonical quantization can thus be understood as a ''first'' or pre-quantization within the framework of conventional QFT. (orig.)
Covariant canonical quantization
Von Hippel, G M; Hippel, Georg M. von; Wohlfarth, Mattias N.R.
2006-01-01
We present a manifestly covariant quantization procedure based on the de Donder-Weyl Hamiltonian formulation of classical field theory. Covariant canonical quantization agrees with conventional canonical quantization only if the parameter space is d=1 dimensional time. In d>1 quantization requires a fundamental length scale, and any bosonic field generates a spinorial wave function, leading to the purely quantum-theoretical emergence of spinors as a byproduct. We provide a probabilistic interpretation of the wave functions for the fields, and apply the formalism to a number of simple examples. These show that covariant canonical quantization produces both the Klein-Gordon and the Dirac equation, while also predicting the existence of discrete towers of identically charged fermions with different masses.
Covariance Applications with Kiwi
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Elliott J.B.
2012-05-01
Full Text Available The Computational Nuclear Physics group at Lawrence Livermore National Laboratory (LLNL is developing a new tool, named ‘Kiwi’, that is intended as an interface between the covariance data increasingly available in major nuclear reaction libraries (including ENDF and ENDL and large-scale Uncertainty Quantification (UQ studies. Kiwi is designed to integrate smoothly into large UQ studies, using the covariance matrix to generate multiple variations of nuclear data. The code has been tested using critical assemblies as a test case, and is being integrated into LLNL's quality assurance and benchmarking for nuclear data.
Bourget, Antoine; Troost, Jan
2016-03-01
We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N = (4 , 4) supersymmetry in two dimensions. For seed target spaces K3 and T 4, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.
Bourget, Antoine
2015-01-01
We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N=(4,4) supersymmetry in two dimensions. For seed target spaces K3 and T4, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.
A Taxonomic Search Engine: Federating taxonomic databases using web services
Page Roderic DM
2005-01-01
Abstract Background The taxonomic name of an organism is a key link between different databases that store information on that organism. However, in the absence of a single, comprehensive database of organism names, individual databases lack an easy means of checking the correctness of a name. Furthermore, the same organism may have more than one name, and the same name may apply to more than one organism. Results The Taxonomic Search Engine (TSE) is a web application written in PHP that quer...
A Taxonomic Search Engine: Federating taxonomic databases using web services
Directory of Open Access Journals (Sweden)
Page Roderic DM
2005-03-01
Full Text Available Abstract Background The taxonomic name of an organism is a key link between different databases that store information on that organism. However, in the absence of a single, comprehensive database of organism names, individual databases lack an easy means of checking the correctness of a name. Furthermore, the same organism may have more than one name, and the same name may apply to more than one organism. Results The Taxonomic Search Engine (TSE is a web application written in PHP that queries multiple taxonomic databases (ITIS, Index Fungorum, IPNI, NCBI, and uBIO and summarises the results in a consistent format. It supports "drill-down" queries to retrieve a specific record. The TSE can optionally suggest alternative spellings the user can try. It also acts as a Life Science Identifier (LSID authority for the source taxonomic databases, providing globally unique identifiers (and associated metadata for each name. Conclusion The Taxonomic Search Engine is available at http://darwin.zoology.gla.ac.uk/~rpage/portal/ and provides a simple demonstration of the potential of the federated approach to providing access to taxonomic names.
Generalized Linear Covariance Analysis
Carpenter, James R.; Markley, F. Landis
2014-01-01
This talk presents a comprehensive approach to filter modeling for generalized covariance analysis of both batch least-squares and sequential estimators. We review and extend in two directions the results of prior work that allowed for partitioning of the state space into solve-for'' and consider'' parameters, accounted for differences between the formal values and the true values of the measurement noise, process noise, and textita priori solve-for and consider covariances, and explicitly partitioned the errors into subspaces containing only the influence of the measurement noise, process noise, and solve-for and consider covariances. In this work, we explicitly add sensitivity analysis to this prior work, and relax an implicit assumption that the batch estimator's epoch time occurs prior to the definitive span. We also apply the method to an integrated orbit and attitude problem, in which gyro and accelerometer errors, though not estimated, influence the orbit determination performance. We illustrate our results using two graphical presentations, which we call the variance sandpile'' and the sensitivity mosaic,'' and we compare the linear covariance results to confidence intervals associated with ensemble statistics from a Monte Carlo analysis.
Using Analysis of Covariance (ANCOVA) with Fallible Covariates
Culpepper, Steven Andrew; Aguinis, Herman
2011-01-01
Analysis of covariance (ANCOVA) is used widely in psychological research implementing nonexperimental designs. However, when covariates are fallible (i.e., measured with error), which is the norm, researchers must choose from among 3 inadequate courses of action: (a) know that the assumption that covariates are perfectly reliable is violated but…
Juan Carlos Gentina; Fernando Acevedo
2016-01-01
Chile has a great tradition of producing and exporting copper. Over the last several decades, it has become the first producer on an international level. Its copper reserves are also the most important on the planet. However, after years of mineral exploitation, the ease of extracting copper oxides and ore copper content has diminished. To keep the production level high, the introduction of new technologies has become necessary. One that has been successful is bioleaching. Chile had the first...
Antonio Levy
2012-01-01
This is the first issue of a new series dedicated to deliver concise information on energy innovation published by the Energy Innovation Center at the IDB. This issue offers a primer on the potential for marine energy in Chile. The ocean is increasingly recognized as a viable source of renewable energy, and Chile, with its long coastline, powerful waves and tidal currents, has captured the attention of marine energy proponents. While harvesting this source of energy would increase sustainabil...
Earth Observing System Covariance Realism
Zaidi, Waqar H.; Hejduk, Matthew D.
2016-01-01
The purpose of covariance realism is to properly size a primary object's covariance in order to add validity to the calculation of the probability of collision. The covariance realism technique in this paper consists of three parts: collection/calculation of definitive state estimates through orbit determination, calculation of covariance realism test statistics at each covariance propagation point, and proper assessment of those test statistics. An empirical cumulative distribution function (ECDF) Goodness-of-Fit (GOF) method is employed to determine if a covariance is properly sized by comparing the empirical distribution of Mahalanobis distance calculations to the hypothesized parent 3-DoF chi-squared distribution. To realistically size a covariance for collision probability calculations, this study uses a state noise compensation algorithm that adds process noise to the definitive epoch covariance to account for uncertainty in the force model. Process noise is added until the GOF tests pass a group significance level threshold. The results of this study indicate that when outliers attributed to persistently high or extreme levels of solar activity are removed, the aforementioned covariance realism compensation method produces a tuned covariance with up to 80 to 90% of the covariance propagation timespan passing (against a 60% minimum passing threshold) the GOF tests-a quite satisfactory and useful result.
Covariant Magnetic Connection Hypersurfaces
Pegoraro, F
2016-01-01
In the single fluid, nonrelativistic, ideal-Magnetohydrodynamic (MHD) plasma description magnetic field lines play a fundamental role by defining dynamically preserved "magnetic connections" between plasma elements. Here we show how the concept of magnetic connection needs to be generalized in the case of a relativistic MHD description where we require covariance under arbitrary Lorentz transformations. This is performed by defining 2-D {\\it magnetic connection hypersurfaces} in the 4-D Minkowski space. This generalization accounts for the loss of simultaneity between spatially separated events in different frames and is expected to provide a powerful insight into the 4-D geometry of electromagnetic fields when ${\\bf E} \\cdot {\\bf B} = 0$.
Universality of Covariance Matrices
Pillai, Natesh S
2011-01-01
We prove the universality of covariance matrices of the form $H_{N \\times N} = {1 \\over N} \\tp{X}X$ where $[X]_{M \\times N}$ is a rectangular matrix with independent real valued entries $[x_{ij}]$ satisfying $\\E \\,x_{ij} = 0$ and $\\E \\,x^2_{ij} = {1 \\over M}$, $N, M\\to \\infty$. Furthermore it is assumed that these entries have sub-exponential tails. We will study the asymptotics in the regime $N/M = d_N \\in (0,\\infty), \\lim_{N\\to \\infty}d_N \
Covariant magnetic connection hypersurfaces
Pegoraro, F.
2016-04-01
> In the single fluid, non-relativistic, ideal magnetohydrodynamic (MHD) plasma description, magnetic field lines play a fundamental role by defining dynamically preserved `magnetic connections' between plasma elements. Here we show how the concept of magnetic connection needs to be generalized in the case of a relativistic MHD description where we require covariance under arbitrary Lorentz transformations. This is performed by defining 2-D magnetic connection hypersurfaces in the 4-D Minkowski space. This generalization accounts for the loss of simultaneity between spatially separated events in different frames and is expected to provide a powerful insight into the 4-D geometry of electromagnetic fields when .
Covariant Projective Extensions
Institute of Scientific and Technical Information of China (English)
许天周; 梁洁
2003-01-01
@@ The theory of crossed products of C*-algebras by groups of automorphisms is a well-developed area of the theory of operator algebras. Given the importance and the success ofthat theory, it is natural to attempt to extend it to a more general situation by, for example,developing a theory of crossed products of C*-algebras by semigroups of automorphisms, or evenof endomorphisms. Indeed, in recent years a number of papers have appeared that are concernedwith such non-classicaltheories of covariance algebras, see, for instance [1-3].
Directory of Open Access Journals (Sweden)
Félix Anibal Vallejos
2005-12-01
Full Text Available The Numeric Taxonomy aims to group operational taxonomic units in clusters (OTUs or taxons or taxa, using the denominated structure analysis by means of numeric methods. These clusters that constitute families are the purpose of this series of projects and they emerge of the structural analysis, of their phenotypical characteristic, exhibiting the relationships in terms of grades of similarity of the OTUs, employing tools such as i the Euclidean distance and ii nearest neighbor techniques. Thus taxonomic evidence is gathered so as to quantify the similarity for each pair of OTUs (pair-group method obtained from the basic data matrix and in this way the significant concept of spectrum of the OTUs is introduced, being based the same one on the state of their characters. A new taxonomic criterion is thereby formulated and a new approach to Computational Taxonomy is presented, that has been already employed with reference to Data Mining, when apply of Machine Learning techniques, in particular to the C4.5 algorithms, created by Quinlan, the degree of efficiency achieved by the TDIDT family's algorithms when are generating valid models of the data in classification problems with the Gain of Entropy through Maximum Entropy Principle. The Numeric Taxonomy aims to group operational taxonomic units in clusters (OTUs or taxons or taxa, using the denominated structure analysis by means of numeric methods. These clusters that constitute families are the purpose of this series of projects and they emerge of the structural analysis, of their phenotypical characteristic, exhibiting the relationships in terms of grades of similarity of the OTUs, employing tools such as i the Euclidean distance and ii nearest neighbor techniques. Thus taxonomic evidence is gathered so as to quantify the similarity for each pair of OTUs (pair-group method obtained from the basic data matrix and in this way the significant concept of spectrum of the OTUs is introduced, being based
Bayes linear covariance matrix adjustment
Wilkinson, Darren J
1995-01-01
In this thesis, a Bayes linear methodology for the adjustment of covariance matrices is presented and discussed. A geometric framework for quantifying uncertainties about covariance matrices is set up, and an inner-product for spaces of random matrices is motivated and constructed. The inner-product on this space captures aspects of our beliefs about the relationship between covariance matrices of interest to us, providing a structure rich enough for us to adjust beliefs about unknown matrices in the light of data such as sample covariance matrices, exploiting second-order exchangeability and related specifications to obtain representations allowing analysis. Adjustment is associated with orthogonal projection, and illustrated with examples of adjustments for some common problems. The problem of adjusting the covariance matrices underlying exchangeable random vectors is tackled and discussed. Learning about the covariance matrices associated with multivariate time series dynamic linear models is shown to be a...
Deriving covariant holographic entanglement
Dong, Xi; Rangamani, Mukund
2016-01-01
We provide a gravitational argument in favour of the covariant holographic entanglement entropy proposal. In general time-dependent states, the proposal asserts that the entanglement entropy of a region in the boundary field theory is given by a quarter of the area of a bulk extremal surface in Planck units. The main element of our discussion is an implementation of an appropriate Schwinger-Keldysh contour to obtain the reduced density matrix (and its powers) of a given region, as is relevant for the replica construction. We map this contour into the bulk gravitational theory, and argue that the saddle point solutions of these replica geometries lead to a consistent prescription for computing the field theory Renyi entropies. In the limiting case where the replica index is taken to unity, a local analysis suffices to show that these saddles lead to the extremal surfaces of interest. We also comment on various properties of holographic entanglement that follow from this construction.
Covariant holographic entanglement negativity
Chaturvedi, Pankaj; Sengupta, Gautam
2016-01-01
We conjecture a holographic prescription for the covariant entanglement negativity of $d$-dimensional conformal field theories dual to non static bulk $AdS_{d+1}$ gravitational configurations in the framework of the $AdS/CFT$ correspondence. Application of our conjecture to a $AdS_3/CFT_2$ scenario involving bulk rotating BTZ black holes exactly reproduces the entanglement negativity of the corresponding $(1+1)$ dimensional conformal field theories and precisely captures the distillable quantum entanglement. Interestingly our conjecture for the scenario involving dual bulk extremal rotating BTZ black holes also accurately leads to the entanglement negativity for the chiral half of the corresponding $(1+1)$ dimensional conformal field theory at zero temperature.
León, Tomás; Grez, Marcela; Prato, Juan Andrés; Torres, Rafael; Ruiz, Sergio
2014-08-01
According to recent surveys, there is a high prevalence of domestic violence (DV) in Chile. A systematic review was conducted in PubMed, Scielo, and Lilacs with the MesH terms "Chile", "Mental Health", "Health", "Domestic Violence", to explore the impact of DV on health in Chile. Eleven studies fulfilled the inclusion criteria. Two studies were prospective, exploring the influence of DV on maternal-infant health. Nine studies explored the influence of DV on mental health in adults. DV was associated with deranged mental health indicators specially anxiety and depressive symptoms and suicidal ideation. Similar results were observed among mothers who were victims of violence and their children. It is concluded that DV is a complex phenomenon with serious effects on health. However the number of studies on the subject is low and new follow up studies are required. Predictive models for DV and effective preventive measures are urgently needed. PMID:25424674
Directory of Open Access Journals (Sweden)
Juan Carlos Gentina
2016-03-01
Full Text Available Chile has a great tradition of producing and exporting copper. Over the last several decades, it has become the first producer on an international level. Its copper reserves are also the most important on the planet. However, after years of mineral exploitation, the ease of extracting copper oxides and ore copper content has diminished. To keep the production level high, the introduction of new technologies has become necessary. One that has been successful is bioleaching. Chile had the first commercial operation in the world exclusively via bioleaching copper sulfides. Nowadays, all bioleaching operations run in the country contribute to an estimated 10% of total copper production. This article presents antecedents that have contributed to the development of copper bioleaching in Chile.
Contributions to the mammalogy of Chile
Pine, Ronald H.; Miller, Sterling D.; Schamberger, Mel L.
1979-01-01
Collections of mammals were made during more than three years of biological investigations in Chile sponsored by the Corporación Nacional Forestal under the aegis of the Peace Corps (Smithsonian Environmental Program). Genera and species hitherto unreported for that country were taken and many useful data concerning distributional patterns of other (mostly little-known) species were gathered. These collections have also proved valuable in better understanding Chilean mammals from a taxonomic point of view and contribute knowledge of the species' natural history. Specimens are to be deposited in the (United States) National Museum of Natural History (USNM) or are to be retained by the Corporación Nacional Forestal, Avda, Bulnes 285, Depto. 401, Santiago. Numbers provided below are field numbers. A final division of specimens between the two institutions has not yet been made. A number of specimens reported here were not taken by Peace Corps personnel but have been obtained by the National Museum of Natural History from other sources. Specimens in the Field Museum of Natural History (FMNH) were used in making comparisons. Some of Fulk's (GWF) specimens are at Texas Tech University. Other are at the Servicio Agricola y Ganadero in Santiago (as are specimens of some introduced species taken by Schamberger). Reise's (DF) are at the Universidad de Chile-Concepción and in his personal collection.
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
After becoming the first female to win a presidential election in the socially conservative country, Chilean President-elect Michelle Bachelet created history again when unveiling a cabinet that was absolutely gender-balanced on January 30. Following similar breakthroughs of women politicians in Liberia and Germany, what happened in Chile is considered another case of women gaining power worldwide.
Cabrera, Lluís; Calafat, A.; Gimeno, D.; Liesa, M.; Proenza, J.; Sàbat, F.; Sáez, Alberto; Santanach, Pere
2008-01-01
6 páginas.-- Book review of "The Geology of Chile", by Teresa Moreno and Wes Gibbons (eds.) (2007). Geological Society. London (United Kingdom). 414 pages, 286 figures including maps, charts and pictures; 27, 5 x 21 cm, ISBN 978-1- 86239-219-9 (hardback) and ISBN 978-1-86239-220-5 (softback).
Evaluation and processing of covariance data
International Nuclear Information System (INIS)
These proceedings of a specialists'meeting on evaluation and processing of covariance data is divided into 4 parts bearing on: part 1- Needs for evaluated covariance data (2 Papers), part 2- generation of covariance data (15 Papers), part 3- Processing of covariance files (2 Papers), part 4-Experience in the use of evaluated covariance data (2 Papers)
The incredible shrinking covariance estimator
Theiler, James
2012-05-01
Covariance estimation is a key step in many target detection algorithms. To distinguish target from background requires that the background be well-characterized. This applies to targets ranging from the precisely known chemical signatures of gaseous plumes to the wholly unspecified signals that are sought by anomaly detectors. When the background is modelled by a (global or local) Gaussian or other elliptically contoured distribution (such as Laplacian or multivariate-t), a covariance matrix must be estimated. The standard sample covariance overfits the data, and when the training sample size is small, the target detection performance suffers. Shrinkage addresses the problem of overfitting that inevitably arises when a high-dimensional model is fit from a small dataset. In place of the (overfit) sample covariance matrix, a linear combination of that covariance with a fixed matrix is employed. The fixed matrix might be the identity, the diagonal elements of the sample covariance, or some other underfit estimator. The idea is that the combination of an overfit with an underfit estimator can lead to a well-fit estimator. The coefficient that does this combining, called the shrinkage parameter, is generally estimated by some kind of cross-validation approach, but direct cross-validation can be computationally expensive. This paper extends an approach suggested by Hoffbeck and Landgrebe, and presents efficient approximations of the leave-one-out cross-validation (LOOC) estimate of the shrinkage parameter used in estimating the covariance matrix from a limited sample of data.
PESI - a taxonomic backbone for Europe
Kouwenberg, Juliana; Boumans, Louis; Hussey, Charles; Hyam, Roger; Nicolson, Nicola; Kirk, Paul; Paton, Alan; Michel, Ellinor; Guiry, Michael D.; Boegh, Phillip S.; Pedersen, Henrik Ærenlund; Enghoff, Henrik; von Raab-Straube, Eckhard; Güntsch, Anton; Geoffroy, Marc; Müller, Andreas; Kohlbecker, Andreas; Berendsohn, Walter; Appeltans, Ward; Arvanitidis, Christos; Vanhoorne, Bart; Declerck, Joram; Vandepitte, Leen; Hernandez, Francisco; Nash, Róisín; Costello, Mark John; Ouvrard, David; Bezard-Falgas, Pascale; Bourgoin, Thierry; Wetzel, Florian Tobias; Glöckler, Falko; Korb, Günther; Ring, Caroline; Hagedorn, Gregor; Häuser, Christoph; Aktaç, Nihat; Asan, Ahmet; Ardelean, Adorian; Borges, Paulo Alexandre Vieira; Dhora, Dhimiter; Khachatryan, Hasmik; Malicky, Michael; Ibrahimov, Shaig; Tuzikov, Alexander; De Wever, Aaike; Moncheva, Snejana; Spassov, Nikolai; Chobot, Karel; Popov, Alexi; Boršić, Igor; Sfenthourakis, Spyros; Kõljalg, Urmas; Uotila, Pertti; Olivier, Gargominy; Dauvin, Jean-Claude; Tarkhnishvili, David; Chaladze, Giorgi; Tuerkay, Michael; Legakis, Anastasios; Peregovits, László; Gudmundsson, Gudmundur; Ólafsson, Erling; Lysaght, Liam; Galil, Bella Sarah; Raimondo, Francesco M.; Domina, Gianniantonio; Stoch, Fabio; Minelli, Alessandro; Spungis, Voldermars; Budrys, Eduardas; Olenin, Sergej; Turpel, Armand; Walisch, Tania; Krpach, Vladimir; Gambin, Marie Therese; Ungureanu, Laurentia; Karaman, Gordan; Kleukers, Roy M.J.C.; Stur, Elisabeth; Aagaard, Kaare; Valland, Nils; Moen, Toril Loennechen; Bogdanowicz, Wieslaw; Tykarski, Piotr; Węsławski, Jan Marcin; Kędra, Monika; M. de Frias Martins, Antonio; Abreu, António Domingos; Silva, Ricardo; Medvedev, Sergei; Ryss, Alexander; Šimić, Smiljka; Marhold, Karol; Stloukal, Eduard; Tome, Davorin; Ramos, Marian A.; Valdés, Benito; Pina, Francisco; Kullander, Sven; Telenius, Anders; Gonseth, Yves; Tschudin, Pascal; Sergeyeva, Oleksandra; Vladymyrov, Volodymyr; Rizun, Volodymyr Bohdanovych; Raper, Chris; Lear, Dan; Stoev, Pavel; Penev, Lyubomir; Rubio, Ana Casino; Backeljau, Thierry; Saarenmaa, Hannu; Ulenberg, Sandrine
2015-01-01
Abstract Background Reliable taxonomy underpins communication in all of biology, not least nature conservation and sustainable use of ecosystem resources. The flexibility of taxonomic interpretations, however, presents a serious challenge for end-users of taxonomic concepts. Users need standardised and continuously harmonised taxonomic reference systems, as well as high-quality and complete taxonomic data sets, but these are generally lacking for non-specialists. The solution is in dynamic, expertly curated web-based taxonomic tools. The Pan-European Species-directories Infrastructure (PESI) worked to solve this key issue by providing a taxonomic e-infrastructure for Europe. It strengthened the relevant social (expertise) and information (standards, data and technical) capacities of five major community networks on taxonomic indexing in Europe, which is essential for proper biodiversity assessment and monitoring activities. The key objectives of PESI were: 1) standardisation in taxonomic reference systems, 2) enhancement of the quality and completeness of taxonomic data sets and 3) creation of integrated access to taxonomic information. New information This paper describes the results of PESI and its future prospects, including the involvement in major European biodiversity informatics initiatives and programs. PMID:26491393
Exploring historical trends using taxonomic name metadata
Directory of Open Access Journals (Sweden)
Schenk Ryan
2008-05-01
Full Text Available Abstract Background Authority and year information have been attached to taxonomic names since Linnaean times. The systematic structure of taxonomic nomenclature facilitates the ability to develop tools that can be used to explore historical trends that may be associated with taxonomy. Results From the over 10.7 million taxonomic names that are part of the uBio system 4, approximately 3 million names were identified to have taxonomic authority information from the years 1750 to 2004. A pipe-delimited file was then generated, organized according to a Linnaean hierarchy and by years from 1750 to 2004, and imported into an Excel workbook. A series of macros were developed to create an Excel-based tool and a complementary Web site to explore the taxonomic data. A cursory and speculative analysis of the data reveals observable trends that may be attributable to significant events that are of both taxonomic (e.g., publishing of key monographs and societal importance (e.g., world wars. The findings also help quantify the number of taxonomic descriptions that may be made available through digitization initiatives. Conclusion Temporal organization of taxonomic data can be used to identify interesting biological epochs relative to historically significant events and ongoing efforts. We have developed an Excel workbook and complementary Web site that enables one to explore taxonomic trends for Linnaean taxonomic groupings, from Kingdoms to Families.
Metagenomic covariation along densely sampled environmental gradients in the Red Sea
Thompson, Luke R
2016-07-15
Oceanic microbial diversity covaries with physicochemical parameters. Temperature, for example, explains approximately half of global variation in surface taxonomic abundance. It is unknown, however, whether covariation patterns hold over narrower parameter gradients and spatial scales, and extending to mesopelagic depths. We collected and sequenced 45 epipelagic and mesopelagic microbial metagenomes on a meridional transect through the eastern Red Sea. We asked which environmental parameters explain the most variation in relative abundances of taxonomic groups, gene ortholog groups, and pathways—at a spatial scale of <2000 km, along narrow but well-defined latitudinal and depth-dependent gradients. We also asked how microbes are adapted to gradients and extremes in irradiance, temperature, salinity, and nutrients, examining the responses of individual gene ortholog groups to these parameters. Functional and taxonomic metrics were equally well explained (75–79%) by environmental parameters. However, only functional and not taxonomic covariation patterns were conserved when comparing with an intruding water mass with different physicochemical properties. Temperature explained the most variation in each metric, followed by nitrate, chlorophyll, phosphate, and salinity. That nitrate explained more variation than phosphate suggested nitrogen limitation, consistent with low surface N:P ratios. Covariation of gene ortholog groups with environmental parameters revealed patterns of functional adaptation to the challenging Red Sea environment: high irradiance, temperature, salinity, and low nutrients. Nutrient-acquisition gene ortholog groups were anti-correlated with concentrations of their respective nutrient species, recapturing trends previously observed across much larger distances and environmental gradients. This dataset of metagenomic covariation along densely sampled environmental gradients includes online data exploration supplements, serving as a community
General covariance in computational electrodynamics
DEFF Research Database (Denmark)
Shyroki, Dzmitry; Lægsgaard, Jesper; Bang, Ole;
2007-01-01
We advocate the generally covariant formulation of Maxwell equations as underpinning some recent advances in computational electrodynamics—in the dimensionality reduction for separable structures; in mesh truncation for finite-difference computations; and in adaptive coordinate mapping as opposed...
Energy Technology Data Exchange (ETDEWEB)
1980-03-01
Simultaneously with its exploitation of offshore hydrocarbon reservoirs Chile is developing the production and selling of LNG. Chile produces a large quantity of associated gas from its reservoirs at Megallanes and processes it at the Manantiales, Cullen and Posesion plants recovering propane, butane and natural gas liguids. The stripped gas is reinjected for pressure maintenance operations. With the completion of the LNG program full use of the gas will be achieved. It will totally meet the needs of combustible liquids for the central and northern parts of the country, a volume of 2200 million cu m/yr. For its treatment natural gas is sent through gas pipelines to the LNG plant at Cabo Negro. By means of a cooling process, the gas is cooled to -160 C where it becomes a liquid and its volume is reduced by a factor of 600. It is then stored in tanks at atmospheric pressure.
International Nuclear Information System (INIS)
The government has made a complete and serious study of many different aspects and possible road maps for nuclear electric power with strong emphasis on safety and energy independence. In the study, the chapter of SFM has not been a relevant issue at this early stage due to the fact that it has been left for later implementation stage. This paper deals with the options Chile might consider in managing its Spent Fuel taking into account foreign experience and factors related to safety, economics, public acceptance and possible novel approaches in spent fuel treatment. The country’s distinctiveness and past experience in this area taking into account that Chile has two research reactors which will have an influence in the design of the Spent Fuel option. (author)
Shrinkage estimators for covariance matrices.
Daniels, M J; Kass, R E
2001-12-01
Estimation of covariance matrices in small samples has been studied by many authors. Standard estimators, like the unstructured maximum likelihood estimator (ML) or restricted maximum likelihood (REML) estimator, can be very unstable with the smallest estimated eigenvalues being too small and the largest too big. A standard approach to more stably estimating the matrix in small samples is to compute the ML or REML estimator under some simple structure that involves estimation of fewer parameters, such as compound symmetry or independence. However, these estimators will not be consistent unless the hypothesized structure is correct. If interest focuses on estimation of regression coefficients with correlated (or longitudinal) data, a sandwich estimator of the covariance matrix may be used to provide standard errors for the estimated coefficients that are robust in the sense that they remain consistent under misspecification of the covariance structure. With large matrices, however, the inefficiency of the sandwich estimator becomes worrisome. We consider here two general shrinkage approaches to estimating the covariance matrix and regression coefficients. The first involves shrinking the eigenvalues of the unstructured ML or REML estimator. The second involves shrinking an unstructured estimator toward a structured estimator. For both cases, the data determine the amount of shrinkage. These estimators are consistent and give consistent and asymptotically efficient estimates for regression coefficients. Simulations show the improved operating characteristics of the shrinkage estimators of the covariance matrix and the regression coefficients in finite samples. The final estimator chosen includes a combination of both shrinkage approaches, i.e., shrinking the eigenvalues and then shrinking toward structure. We illustrate our approach on a sleep EEG study that requires estimation of a 24 x 24 covariance matrix and for which inferences on mean parameters critically
Chile: segundo tiempo Chile: Half-time
Directory of Open Access Journals (Sweden)
ROBERT L FUNK
2009-01-01
Full Text Available El artículo examina el año político chileno, ofreciendo un análisis crítico del concepto de 'segundo tiempo' autoimpuesto por la presidenta Michelle Bachelet a comienzos del 2008. Resumiendo algunas de las políticas implementadas, el trabajo cuestiona si se logró marcar una linea y dejar atrás los dos primeros y difíciles años del cuarto gobierno de la Concertación. Analizando las medidas tomadas y las encuestas de opinión pública, se encuentra que el reenfoque de las prioridades del gobierno y una complicada coyuntura externa ayudó a levantar los niveles de apoyo de la presidenta y su gobierno.The article examines the political year in Chile, offering a critical analysis of the concept of 'Second Period' which President Michelle Bachelet defined at the beginning of 2008. Summarising some of the policies implemented, the piece asks whether the government was able to draw a line, leaving behind the first, difficult two years of the Concertación s fourth government. Analyzing the measures taken and public opinion polls, the paper finds that a re-focussing of the government's priorities together with a complicated external environment helped to raise support for the president as well as her government.
Levy Matrices and Financial Covariances
Burda, Zdzislaw; Jurkiewicz, Jerzy; Nowak, Maciej A.; Papp, Gabor; Zahed, Ismail
2003-10-01
In a given market, financial covariances capture the intra-stock correlations and can be used to address statistically the bulk nature of the market as a complex system. We provide a statistical analysis of three SP500 covariances with evidence for raw tail distributions. We study the stability of these tails against reshuffling for the SP500 data and show that the covariance with the strongest tails is robust, with a spectral density in remarkable agreement with random Lévy matrix theory. We study the inverse participation ratio for the three covariances. The strong localization observed at both ends of the spectral density is analogous to the localization exhibited in the random Lévy matrix ensemble. We discuss two competitive mechanisms responsible for the occurrence of an extensive and delocalized eigenvalue at the edge of the spectrum: (a) the Lévy character of the entries of the correlation matrix and (b) a sort of off-diagonal order induced by underlying inter-stock correlations. (b) can be destroyed by reshuffling, while (a) cannot. We show that the stocks with the largest scattering are the least susceptible to correlations, and likely candidates for the localized states. We introduce a simple model for price fluctuations which captures behavior of the SP500 covariances. It may be of importance for assets diversification.
DEFF Research Database (Denmark)
Scarpaci, Joseph L.
Primary medical care in Chile: accessibility under military rule [Front Cover] [Front Matter] [Title Page] Contents Tables Figures Preface Chapter 1: Introduction Chapter 2: The Restructuring of Medical Care Financing in Chile Chapter 3: Inflation and Medical Care Accessibility Chapter 4: Help...
Covariance evaluation work at LANL
Energy Technology Data Exchange (ETDEWEB)
Kawano, Toshihiko [Los Alamos National Laboratory; Talou, Patrick [Los Alamos National Laboratory; Young, Phillip [Los Alamos National Laboratory; Hale, Gerald [Los Alamos National Laboratory; Chadwick, M B [Los Alamos National Laboratory; Little, R C [Los Alamos National Laboratory
2008-01-01
Los Alamos evaluates covariances for nuclear data library, mainly for actinides above the resonance regions and light elements in the enUre energy range. We also develop techniques to evaluate the covariance data, like Bayesian and least-squares fitting methods, which are important to explore the uncertainty information on different types of physical quantities such as elastic scattering angular distribution, or prompt neutron fission spectra. This paper summarizes our current activities of the covariance evaluation work at LANL, including the actinide and light element data mainly for the criticality safety study and transmutation technology. The Bayesian method based on the Kalman filter technique, which combines uncertainties in the theoretical model and experimental data, is discussed.
Covariant jump conditions in electromagnetism
Itin, Yakov
2014-01-01
A generally covariant four-dimensional representation of Maxwell's electrodynamics in a generic material medium can be achieved straightforwardly in the metric-free formulation of electromagnetism. In this setup, the electromagnetic phenomena described by two tensor fields, which satisfy Maxwell's equations. A generic tensorial constitutive relation between these fields is an independent ingredient of the theory. By use of different constitutive relations (local and non-local, linear and non-linear, etc.), a wide area of applications can be covered. In the current paper, we present the jump conditions for the fields and for the energy-momentum tensor on an arbitrarily moving surface between two media. From the differential and integral Maxwell equations, we derive the covariant boundary conditions, which are independent of any metric and connection. These conditions include the covariantly defined surface current and are applicable to an arbitrarily moving smooth curved boundary surface. As an application of ...
Chile rural electrification cooperation
Energy Technology Data Exchange (ETDEWEB)
Flowers, L. [National Renewable Energy Lab., Golden, CO (United States)
1997-12-01
The author describes a joint program to use renewables for rural electrification projects in Chile. The initial focus was in a limited part of the country, involving wind mapping, pilot project planning, training, and development of methodologies for comparative evaluations of resources. To this point three wind hybrid systems have been installed in one region, as a part of the regional private utility, and three additional projects are being designed. Additional resource assessment and training is ongoing. The author points out the difficulties in working with utilities, the importance of signed documentation, and the need to look at these programs as long term because of the time involved in introducing such new technologies.
Chile: Transantiago recargado Chile: Transantiago Reloaded
Directory of Open Access Journals (Sweden)
RODRIGO MARDONES Z
2008-01-01
Full Text Available El 2007 fue el segundo año del gobierno de Michelle Bachelet. Se trató de un año sin elecciones; con un buen desempeño económico, a pesar de una inflación creciente en los últimos meses; y marcado por la discusión sobre escándalos de corrupción. Sin embargo, lo que más afectó al Gobierno fue la desastrosa puesta en marcha de la reforma al sistema de transporte público de la capital: Transantiago. Este puso un velo sobre los importantes avances en materias previsionales y educacionales, cuestionando no sólo la capacidad ejecutiva del Gobierno, sino que profundizando un flanco de indisciplina al interior de la coalición oficialista (Concertación; síntoma de su desgaste después de 17 años ocupando la Presidencia de Chile.The year 2007 was the second in Michelle Bachelet’s presidencial term. It was a year free of elections, exhibiting a fairly good economic performance, despite the high rate of inflation shown during the last months. Public discussion on corruption escandals was frequent; however, the most important issue was the disestrous beginning of the reform on the public transportation system of the country’s capital: Transantiago. This has placed a veil over the important achievements on the pension system and education, questioning not only the government’s capacity, but also opening and edge of indiscipline within the ruling coalition (Concertación, which is a symtom of its erosion after 17 years in the presidential office.
Cosmic Censorship Conjecture revisited: Covariantly
Hamid, Aymen I M; Maharaj, Sunil D
2014-01-01
In this paper we study the dynamics of the trapped region using a frame independent semi-tetrad covariant formalism for general Locally Rotationally Symmetric (LRS) class II spacetimes. We covariantly prove some important geometrical results for the apparent horizon, and state the necessary and sufficient conditions for a singularity to be locally naked. These conditions bring out, for the first time in a quantitative and transparent manner, the importance of the Weyl curvature in deforming and delaying the trapped region during continual gravitational collapse, making the central singularity locally visible.
2010-04-01
... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Chiles Valley. 9.154... Chiles Valley. (a) Name. The name of the viticultural area described in this section is “Chiles Valley.” (b) Approved maps. The appropriate maps for determining the boundary of the Chiles...
Causes of taxonomic sorting by adults: a test of the thematic-to-taxonomic shift.
Murphy, G L
2001-12-01
The tendency among adults to sort items into taxonomic and thematic categories was examined in two experiments. Past demonstrations of adults' preference for taxonomic categories have usually not used stimuli with a salient thematic organization. The stimuli in Experiment 1 could be divided into three equal-size categories either thematically or taxonomically. Under two sets of instructions, the majority of the college-student subjects sorted thematically. In Experiment 2, a subset of the stimuli was changed so that those within it were strongly taxonomically organized. Subjects then preferred to sort the remaining items taxonomically as well. The two experiments explain why many past sorting studies have yielded a taxonomic preference in adults and provide further evidence against a global change from thematic to taxonomic preference with development. PMID:11848607
Relativistic covariance of Ohm's law
Starke, R
2014-01-01
The derivation of relativistic generalizations of Ohm's law has been a long-term issue in theoretical physics with deep implications for the study of relativistic plasmas in astrophysics and cosmology. Here we propose an alternative route to this problem by introducing the most general Lorentz covariant first order response law, which is written in terms of the fundamental response tensor $\\chi^\\mu_{~\
1995-02-01
ESO, the European Southern Observatory, in reply to questions raised by the international media, as well as an ongoing debate about the so-called "Paranal case" in Chilean newspapers, would like to make a number of related observations concerning its status and continued operation in that country [1]. THE ESO OBSERVATORY SITES IN CHILE The European Southern Observatory, an international organisation established and supported by eight European countries, has been operating more than 30 years in the Republic of Chile. Here ESO maintains one of the world's prime astronomical observatories on the La Silla mountain in the southern part of the Atacama desert. This location is in the Fourth Chilean Region, some 600 km north of Santiago de Chile. In order to protect the La Silla site against dust and light pollution from possible future mining industries, roads and settlements, ESO early acquired the territory around this site. It totals about 825 sq. km and has effectively contributed to the preservation of its continued, excellent "astronomical" quality. Each year, more than 500 astronomers from European countries, Chile and elsewhere profit from this when they come to La Silla to observe with one or more of the 15 telescopes now located there. In 1987, the ESO Council [2] decided to embark upon one of the most prestigious and technologically advanced projects ever conceived in astronomy, the Very Large Telescope (VLT). It will consist of four interconnected 8.2-metre telescopes and will become the largest optical telescope in the world when it is ready. It is safe to predict that many exciting discoveries will be made with this instrument, and it will undoubtedly play a very important role in our exploration of the distant universe and its many mysteries during the coming decades. THE VLT AND PARANAL In order to find the best site for the VLT, ESO performed a thorough investigation of many possible mountain tops, both near La Silla and in Northern Chile. They showed
2002-01-01
On February 5, 2002, the dense smoke from numerous forest fires stretched out over the Pacific Ocean about 400 miles south of Santiago, Chile. This true-color Moderate-resolution Imaging Spectroradiometer (MODIS) image shows the fires, which are located near the city of Temuco. The fires are indicated with red dots (boxes in the high-resolution imagery). The fires were burning near several national parks and nature reserves in an area of the Chilean Andes where tourism is very popular. Southeast of the fires, the vegetation along the banks of the Rio Negro in Argentina stands out in dark green. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC
Discrete Symmetries in Covariant LQG
Rovelli, Carlo
2012-01-01
We study time-reversal and parity ---on the physical manifold and in internal space--- in covariant loop gravity. We consider a minor modification of the Holst action which makes it transform coherently under such transformations. The classical theory is not affected but the quantum theory is slightly different. In particular, the simplicity constraints are slightly modified and this restricts orientation flips in a spinfoam to occur only across degenerate regions, thus reducing the sources of potential divergences.
Shrinkage Estimators for Covariance Matrices
Daniels, Michael J.; Kass, Robert E.
2001-01-01
Estimation of covariance matrices in small samples has been studied by many authors. Standard estimators, like the unstructured maximum likelihood estimator (ML) or restricted maximum likelihood (REML) estimator, can be very unstable with the smallest estimated eigenvalues being too small and the largest too big. A standard approach to more stably estimating the matrix in small samples is to compute the ML or REML estimator under some simple structure that involves estimation of fewer paramet...
Alexandrov, Sergei
2007-01-01
We generalize the covariant c-map found in hep-th/0701214 including perturbative quantum corrections. We also perform explicitly the superconformal quotient from the hyperkahler cone obtained by the quantum c-map to the quaternion-Kahler space, which is the moduli space of hypermultiplets. As a result, the perturbatively corrected metric on the moduli space is found in a simplified form comparing to the expression known in the literature.
Are Maxwell's equations Lorentz-covariant?
Redzic, D V
2016-01-01
The statement that Maxwell's electrodynamics in vacuum is already covariant under Lorentz transformations is commonplace in the literature. We analyse the actual meaning of that statement and demonstrate that Maxwell's equations are perfectly fit to be Lorentz-covariant; they become Lorentz-covariant if we construct to be so, by postulating certain transformation properties of field functions. In Aristotelian terms, the covariance is a plain potentiality, but not necessarily entelechy.
Covariant Perturbations of Schwarzschild Black Holes
Clarkson, Chris A.; Barrett, Richard K.
2002-01-01
We present a new covariant and gauge-invariant perturbation formalism for dealing with spacetimes having spherical symmetry (or some preferred spatial direction) in the background, and apply it to the case of gravitational wave propagation in a Schwarzschild black hole spacetime. The 1+3 covariant approach is extended to a `1+1+2 covariant sheet' formalism by introducing a radial unit vector in addition to the timelike congruence, and decomposing all covariant quantities with respect to this....
The H-Covariant Strong Picard Groupoid
Jansen, Stefan; Waldmann, Stefan
2004-01-01
The notion of H-covariant strong Morita equivalence is introduced for *-algebras over C = R(i) with an ordered ring R which are equipped with a *-action of a Hopf *-algebra H. This defines a corresponding H-covariant strong Picard groupoid which encodes the entire Morita theory. Dropping the positivity conditions one obtains H-covariant *-Morita equivalence with its H-covariant *-Picard groupoid. We discuss various groupoid morphisms between the corresponding notions of the Picard groupoids. ...
Covariant jump conditions in electromagnetism
Itin, Yakov
2012-02-01
A generally covariant four-dimensional representation of Maxwell's electrodynamics in a generic material medium can be achieved straightforwardly in the metric-free formulation of electromagnetism. In this setup, the electromagnetic phenomena are described by two tensor fields, which satisfy Maxwell's equations. A generic tensorial constitutive relation between these fields is an independent ingredient of the theory. By use of different constitutive relations (local and non-local, linear and non-linear, etc.), a wide area of applications can be covered. In the current paper, we present the jump conditions for the fields and for the energy-momentum tensor on an arbitrarily moving surface between two media. From the differential and integral Maxwell equations, we derive the covariant boundary conditions, which are independent of any metric and connection. These conditions include the covariantly defined surface current and are applicable to an arbitrarily moving smooth curved boundary surface. As an application of the presented jump formulas, we derive a Lorentzian type metric as a condition for existence of the wave front in isotropic media. This result holds for ordinary materials as well as for metamaterials with negative material constants.
Competing risks and time-dependent covariates
DEFF Research Database (Denmark)
Cortese, Giuliana; Andersen, Per K
2010-01-01
Time-dependent covariates are frequently encountered in regression analysis for event history data and competing risks. They are often essential predictors, which cannot be substituted by time-fixed covariates. This study briefly recalls the different types of time-dependent covariates...
Covariant Quantization of D-branes
Kallosh, Renata
1997-01-01
We have found that kappa-symmetry allows a covariant quantization provided the ground state of the theory is strictly massive. For D-p-branes a Hamiltonian analysis is performed to explain the existence of a manifestly supersymmetric and Lorentz covariant description of the BPS states of the theory. The covariant quantization of the D-0-brane is presented as an example.
Covariance Evaluation Methodology for Neutron Cross Sections
Energy Technology Data Exchange (ETDEWEB)
Herman,M.; Arcilla, R.; Mattoon, C.M.; Mughabghab, S.F.; Oblozinsky, P.; Pigni, M.; Pritychenko, b.; Songzoni, A.A.
2008-09-01
We present the NNDC-BNL methodology for estimating neutron cross section covariances in thermal, resolved resonance, unresolved resonance and fast neutron regions. The three key elements of the methodology are Atlas of Neutron Resonances, nuclear reaction code EMPIRE, and the Bayesian code implementing Kalman filter concept. The covariance data processing, visualization and distribution capabilities are integral components of the NNDC methodology. We illustrate its application on examples including relatively detailed evaluation of covariances for two individual nuclei and massive production of simple covariance estimates for 307 materials. Certain peculiarities regarding evaluation of covariances for resolved resonances and the consistency between resonance parameter uncertainties and thermal cross section uncertainties are also discussed.
Directory of Open Access Journals (Sweden)
A Crovetto
2008-01-01
Full Text Available Los ectoparásitos de los mamíferos marinos en Chile son poco conocidos. Se recolectaron individuos en animales adultos y jóvenes de una lobería reproductiva de lobo marino común (Otaria flavescens en Isla Metalqui, de la Región de Los Lagos, Chile. Se identifican y describen los especímenes de Anoplura apoyado en claves existentes. Dicha descripción y la comparación con la evolución y distribución de la familia Otariidae en el mundo nos permite concluir que Antarctophthirus microchir es una especie descrita por primera vez en Chile y podría representar una posible evidencia de un origen monofilético de los grupos de Otariidae en los hemisferios norte y sur.The ectoparasitic fauna associated to marine mammals is scarcely known in Chile. This report deals with a sample of Anoplura parasites collected from adult and juvenile Otaria flavescens, the southern sea lion, at the Los Lagos Region, Chile. The Anoplura were taxonomically determined using the existent keys and they were subsequently described. This is the first record of Antarctophthirus microchir in Chile which, together with what is already known about the geographical distribution and the world evolutionary history of the Otariidae, could represent another evidence of the monophyly of the northern and southern hemisphere Otariidae groups.
2002-01-01
Full resolution visible and near-infrared image (1.4 MB) Full resolution shortwave infrared image (1.6 MB) This Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image covers 30 by 23 km (full images 30 x 37 km) in the Atacama Desert, Chile, and was acquired on April 23, 2000. The Escondida copper, gold, and silver open-pit mine is at an elevation of 3050 m, and began operations in 1990. Current capacity is 127,000 tons/day of ore; in 1999 production totaled 827,000 tons of copper, 150,000 ounces of gold, and 3.53 million ounces of silver. Primary concentrate of the ore is done on-site; the concentrate is then sent to the coast for further processing through a 170 km long, 9-inch pipe. Escondida is related geologically to three porphyry bodies intruded along the Chilean West Fissure Fault System. A high grade supergene cap overlies primary sulfide ore. The top image is a conventional 3-2-1 (near infrared, red, green) RGB composite. The bottom image displays shortwave infrared bands 4-6-8 (1.65um, 2.205um, 2.33um) in RGB, and highlights the different rock types present on the surface, as well as the changes caused by mining. Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team
Montoya Leiva, M
1996-01-01
Servicio Paz y Justicia (SERPAJ) is a nongovernmental organization (NGO) established in Chile in 1977. It supports fundamental human dignity and rights by fighting discrimination and exclusion based upon individual differences. SERPAJ promotes training, organization, and the political participation of community members as part of the democratic process, working mainly with the at risk women, street children, and youth of Santiago's working-class neighborhoods. Groups participate in workshops and training courses on human rights and development, civic education, and methods of non-violent community action. In 1987, SERPAJ-Sur Oriente began to include the topic of sexuality and AIDS/STDs in courses training working-class women as community human rights agents. The NGO is therefore one of the first mainstream Chilean human rights organizations to incorporate HIV/AIDS issues. A basic facts brochure was developed, followed by a pilot education project developed in one neighborhood which was then systematically replicated in other neighborhoods. The comments of some people who have participated in SERPAJ workshops are presented.
Directory of Open Access Journals (Sweden)
Miguel Alejandro Bustamante-Ubilla
2015-01-01
Full Text Available El presente estudio tiene por objetivo caracterizar el clima organizacional al interior de 2 hospitales dealta complejidad de Chile, determinando las dimensiones más y menos influyentes. Para su desarrollose aplicó un cuestionario que consta de 71 variables agrupadas en 14 dimensiones a una muestra de561 funcionarios. La interpretación de los resultados se realizó a través del análisis del valor prome-dio estandarizado y su confiabilidad ratificada mediante el alfa de Cronbach. A partir de lo anterior, sedeterminó que las dimensiones que influyen por encima del promedio fueron: identidad, motivaciónlaboral y responsabilidad; en tanto que las dimensiones que muestran un nivel de impacto por debajodel promedio resultaron ser: equipo y distribución de personas y material, administración del conflictoy comunicación.© 2015 Universidad ICESI. Publicado por Elsevier España, S.L.U. Este es un artículo Open Access bajo lalicencia CC BY (http://creativecommons.org/licenses/by/4.0/.
Converting Taxonomic Descriptions to New Digital Formats
Directory of Open Access Journals (Sweden)
Hong Cui
2008-01-01
Full Text Available Abstract.--The majority of taxonomic descriptions is currently in print format. The majority of digital descriptions are in formats such as DOC, HTML, or PDF and for human readers. These formats do not convey rich semantics in taxonomic descriptions for computer-aided process. Newer digital formats such as XML and RDF accommodate semantic annotations that allow computers to process the rich semantics on human's behalf, thus open up opportunities for a wide range of innovative usages of taxonomic descriptions, such as searching in more precise and flexible ways, integrating with gnomic and geographic information, generating taxonomic keys automatically, and text data mining and information visualization etc. This paper discusses the challenges in automated conversion of multiple collections of descriptions to XML format and reports an automated system, MARTT. MARTT is a machine-learning system that makes use of training examples to tag new descriptions into XML format. A number of utilities are implemented as solutions to the challenges. The utilities are used to reduce the effort for training example preparation, to facilitate the creation of a comprehensive schema, and to predict system performance on a new collection of descriptions. The system has been tested with several plant and alga taxonomic publications including Flora of China and Flora of North America.
Modernitet og forbrugskultur i Chile
DEFF Research Database (Denmark)
Cristoffanini, Pablo Rolando
2012-01-01
I de sidste årtier er Chile blevet et egentligt forbrugersamfund. Udbredelsen af forbrugskulturen og forbrugerismen er centrale fænomener i chilenernes dagligliv og har nået et omfang, som har konsekvenser for de borgere, der ikke kan deltage fuldt ud heri, noget som er typisk for et samfund med en...... ujævn økonomisk udvikling og med store sociale forskelle. Denne proces er ikke et produkt af en stille, fredelig og naturlig samfundsudvikling, således som magteliten og de toneangivende intellektuelle i Chile har fremstillet det. Som jeg vil vise, er skabelsen af et egentlig forbrugssamfund knyttet til...... til i dag. Ifølge disse er Chile blevet et moderne samfund netop i kraft af, at Chile er et ægte forbrugersamfund med alt, hvad dette indebærer, såvel materielt som symbolsk. For det tredje er billedet af Chile som en ”supermoderne” nation i den latinamerikanske kontekst en udbredt forestilling hos...
Institute of Scientific and Technical Information of China (English)
Li Zhen
2011-01-01
@@ Chile is the first country to establish coopera-tive relations with China in South America, and also the first one to support China's ac-cession to the World Trade Organization.In 2005, Chile and China signed a free trade agreement.After that, China has become Chile's largest trad-ing partner, and Chile become China's second largest partner in South America.
China and Chile Signing Free Trade Agreement
Institute of Scientific and Technical Information of China (English)
Shen; Danyang
2005-01-01
Mr. Bo Xilai, Minister of Commerce of China, and Mr.Walker, Foreign Minister of Chile, signed the China-Chile FTA on behalf of their respective government on November 18, 2005. Chinese President Hu Jintao and Chile President Lagos attended the signing ceremony, according to a press release on the website of Network Center of MOFCOM.……
China and Chile Signing Free Trade Agreement
Institute of Scientific and Technical Information of China (English)
Shen Danyang
2005-01-01
@@ Mr. Bo Xilai, Minister of Commerce of China, and Mr.Walker, Foreign Minister of Chile, signed the China-Chile FTA on behalf of their respective government on November 18, 2005. Chinese President Hu Jintao and Chile President Lagos attended the signing ceremony, according to a press release on the website of Network Center of MOFCOM.
ISSUES IN NEUTRON CROSS SECTION COVARIANCES
Energy Technology Data Exchange (ETDEWEB)
Mattoon, C.M.; Oblozinsky,P.
2010-04-30
We review neutron cross section covariances in both the resonance and fast neutron regions with the goal to identify existing issues in evaluation methods and their impact on covariances. We also outline ideas for suitable covariance quality assurance procedures.We show that the topic of covariance data remains controversial, the evaluation methodologies are not fully established and covariances produced by different approaches have unacceptable spread. The main controversy is in very low uncertainties generated by rigorous evaluation methods and much larger uncertainties based on simple estimates from experimental data. Since the evaluators tend to trust the former, while the users tend to trust the latter, this controversy has considerable practical implications. Dedicated effort is needed to arrive at covariance evaluation methods that would resolve this issue and produce results accepted internationally both by evaluators and users.
Covariant diagrams for one-loop matching
Zhang, Zhengkang
2016-01-01
We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gauge-covariant quantities and are thus dubbed "covariant diagrams." The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.
Kalman Filtering with Unknown Noise Covariances
Nilsson, Martin
2006-01-01
Since it is often difficult to identify the noise covariances for a Kalman filter, they are commonly considered design variables. If so, we can as well try to choose them so that the corresponding Kalman filter has some nice form. In this paper, we introduce a one-parameter subfamily of Kalman filters with the property that the covariance parameters cancel in the expression for the Kalman gain. We provide a simple criterion which guarantees that the implicitly defined process covariance matri...
Balancing Covariates via Propensity Score Weighting
Li, Fan; Morgan, Kari Lock; Zaslavsky, Alan M.
2014-01-01
Covariate balance is crucial for an unconfounded descriptive or causal comparison. However, lack of balance is common in observational studies. This article considers weighting strategies for balancing covariates. We define a general class of weights-the balancing weights-that balance the weighted distributions of the covariates between treatment groups. These weights incorporate the propensity score to weight each group to an analyst-selected target population. This class unifies existing we...
A taxonomic analysis of multihospital systems.
Lewis, B.L.; Alexander, J.
1986-01-01
Research to date on multihospital systems has proved largely uninformative, in part because similarities and differences among these organizations have not been addressed systematically. Through numeric classification, this article identifies populations of multihospital systems that share similar organizational attributes. Drawing on McKelvey's classification theory, 16 organizational characteristics of 160 multihospital systems are analyzed using a series of taxonomic techniques, including ...
Taxonomic revision of Ustilago, Sporisorium and Macalpinomyces.
McTaggart, A R; Shivas, R G; Geering, A D W; Vánky, K; Scharaschkin, T
2012-12-01
Morphological characters within the Ustilago-Sporisorium-Macalpinomyces complex are defined explicitly. The genera Sporisorium and Anthracocystis are emended to reflect morphological synapomorphies. Three new genera, Langdonia, Stollia and Triodiomyces are described based on soral synapomorphies and host classification. The new classification of the Ustilago-Sporisorium-Macalpinomyces complex incorporates 142 new taxonomic combinations. PMID:23606769
Taxonomic revision of Ustilago, Sporisorium and Macalpinomyces
McTaggart, A.R.; Shivas, R.G.; Geering, A.D.W.; Vánky, K.; Scharaschkin, T
2012-01-01
Morphological characters within the Ustilago-Sporisorium-Macalpinomyces complex are defined explicitly. The genera Sporisorium and Anthracocystis are emended to reflect morphological synapomorphies. Three new genera, Langdonia, Stollia and Triodiomyces are described based on soral synapomorphies and host classification. The new classification of the Ustilago-Sporisorium-Macalpinomyces complex incorporates 142 new taxonomic combinations.
A taxonomic revision of Lamium (Lamiaceae)
Mennema, J.
1989-01-01
The present study deals with the systematics and taxonomy of the genus Lamium (Lamiaceae). The taxonomic revision is mainly based on the study of herbarium collections, and to a smaller degree on field observations and abstracts from literature. The research was done at the Rijksherbarium, Leyden, w
Conformal covariance and the split property
Morinelli, Vincenzo; Weiner, Mihály
2016-01-01
We show that for a conformal local net of observables on the circle, the split property is automatic. Both full conformal covariance (i.e. diffeomorphism covariance) and the circle-setting play essential roles in this fact, while by previously constructed examples it was already known that even on the circle, M\\"obius covariance does not imply the split property. On the other hand, here we also provide an example of a local conformal net living on the two-dimensional Minkowski space, which - although being diffeomorphism covariant - does not have the split property.
Incongruence between cladistic and taxonomic systems.
Grant, Verne
2003-09-01
Cladistic and taxonomic treatments of the same plant group usually exhibit a mixture of congruences and incongruences. The question arises in the case of the incongruences as to which version is right and which is wrong. Many cladists believe that cladistics is a superior approach and gives the best results. There are several conceptual and methodological differences between cladistics and taxonomy that cause incongruence. One important conceptual difference is the use of different criteria for grouping: order of branching vs. similarity and difference (clades vs. taxa). Another is the policy regarding paraphyletic groups: to ban them in cladistics but ignore the ban in taxonomy. These two differences automatically lead to some incongruences. One approach is not right and the other wrong; each is operating by its own standards. However, when cladists apply the paraphyly rule to a taxonomic system and conclude that it needs revision to eliminate paraphyly, as cladists often do, they are judging the taxonomic system by a wrong standard. Several differences between the two schools in the use and handling of characters can also cause incongruence. First consider phenetic characters. Taxonomy uses a very wide range of these, whereas phenetic cladistics sets restrictions on the selection of characters, which deprive it of potentially useful evidence. Taxonomic systems generally rest on a broader empirical foundation than phenetic cladistic systems. Next, consider molecular cladistics, which is the leader in the use of DNA evidence. Two sources of incongruence between molecular cladistics and taxonomic systems can come into play here. First, the molecular evidence used in cladistics comes mainly from cytoplasmic organelles, whereas taxonomic systems are based on characters that are determined mainly by the chromosomal genome. More generally, the database in a molecular cladogram is, in itself, too narrow to serve as a foundation for an organismic classification. In cases
Kirkwood, Julieta
1983-01-01
Political parties in Chile of both the left and right have focused more on drawing women into their ideologies than on considering what political issues mean to women. A look at feminist thought shows how political life for women includes not only the traditional political arena but also domestic life. (IS)
The biomethane potential in Chile
International Nuclear Information System (INIS)
Within the last decade natural gas gained considerable importance in Chile. The contribution of natural gas within the energy system will increase in the future by predicted 3.6% annually until the year 2015. Due to limited resources within its own country, the energy system of Chile depends on natural gas imports preferential from Argentina. Therefore, the aim of several stakeholders from policy and industry is to reduce the share of imported primary energy within the overall energy system. In order to reach this goal, the use of domestic resources and particularly the utilisation of biomass as one of the most important renewable sources of energy in Chile could play an important role. Against this background, the goal of this paper is the analysis of the technical potentials of biomethane as a substitute for natural gas. For the production of biomethane the anaerobic or bio-chemical (i.e. Biogas) as well as the thermo-chemical conversion pathways (i.e. Bio-SNG) are considered. The results of this analysis show that biomass converted to biomethane is a promising energy provision option for Chile and it contributes to the reduction of greenhouse gas emissions
Corporate Governance Country Assessment : Chile
World Bank
2003-01-01
Chile's equity market is fairly large and successful. The market capitalization of the 249 listed firms represented 89 percent of GDP at year-end, 2001. Corporate ownership is concentrated and pyramid structures are common. Business groups/conglomerates are the predominant corporate form. Institutional investors, especially pension funds, are active equity investors. The Securities Market ...
A review of the non-bulimulid terrestrial Mollusca from the Region of Atacama, northern Chile
Araya, Juan Francisco; Catalán, Ricardo
2014-01-01
Abstract Terrestrial mollusca are sparsely studied in Chile and, for the first time, a formal record of the diversity of land snails in northern Chile is reported. Coastal and desertic areas in the Region of Atacama, in the border of the Atacama desert and the Pacific Ocean, were surveyed with the aim to describe the presence and distribution of this poorly known fauna. Of the fourteen species recorded, the geographic distribution records for nine species are extended, and some taxa are recorded for the first time since their original descriptions. All, except one, of the fourteen terrestrial molluscan species occurring in the area are endemic to Chile; they are all terrestrial species, most of them have a restricted geographic distribution, and none of them is currently protected by law. The results reveal that the region of Atacama has one of the most diverse terrestrial snail biodiversity in Chile, ranking only after the Juan Fernandez Archipelago. Distribution records of all the studied species and a taxonomic key are also provided. PMID:24715800
The shallow-water chitons (Mollusca, Polyplacophora of Caldera, Region of Atacama, northern Chile
Directory of Open Access Journals (Sweden)
Juan Francisco Araya
2015-03-01
Full Text Available The Molluscan species of the northern littoral of Chile have been sparsely studied. This work reviews for the first time the diversity of polyplacophoran molluscs around the port of Caldera, in the Region of Atacama (26°45’49”S; 70°45’17”W to 27°20’23”S; 70°56’46”W, northern Chile. Eleven species were found in this study: Acanthopleura echinata (Barnes, 1824; Callistochiton pulchellus (Gray, 1828; Calloplax vivipara (Plate, 1899, Chaetopleura peruviana (Lamarck, 1819; Chiton cumingsii Frembly, 1827; Chiton granosus Frembly, 1827; Chiton magnificus Deshayes, 1827; Enoplochiton niger (Barnes, 1824, Radsia barnesii (Gray, 1828, Tonicia atrata (G. B. Sowerby II, 1840 and Tonicia chilensis (Frembly, 1827. All of the species occurring in the area have distributions in the southeastern Pacific Ocean, from Ecuador to central Chile, and three of them are species endemic to the Chilean coasts (Calloplax vivipara, Radsia barnesii, and Tonicia atrata. This diversity of species is comparable to that of better surveyed faunas of central and southern Chile or Patagonia. Of the eleven species recorded, the geographic distribution records for Callistochiton pulchellus, Radsia barnesii and Tonicia atrata are extended, and Calloplax vivipara is found alive again after 40 years, filling a gap in its known distribution. Illustrations of living specimens in their habitat, distribution records and a taxonomic key for all the studied taxa are also provided.
Jafari, A.; Ayoubi, S.; Khademi, H.; Finke, P. A.; Toomanian, N.
2013-11-01
There is a growing demand for digital soil maps for environmental planning, modeling and management. If mapped soil classes are taken from a hierarchical taxonomic system, a question arises: which taxonomic level is most appropriate to be depicted on the map with a given sample size, available environmental covariates and the strength of predictive relations between covariates and the soil classes? Pedodiversity, the study and measurement of soil diversity, can be considered as a framework to analyze spatial patterns depicted on soil maps. This paper discusses the selection of the taxonomic level for soil mapping in an arid region in southeast Iran on the basis of (1) the purity of a digital soil class map derived from an artificial neural network (ANN) prediction method using environmental covariates and (2) pedodiversity indices of these soil maps. The prediction of soil classes and the calculation of diversity indices were carried out for taxonomic categories of order, suborder, great group, and subgroup. Using the feed forward back-propagation algorithm, three-layer ANNs with input, hidden and output layers were trained for soil class prediction at each category level. In most predictions, the combined use of terrain attributes and geomorphic surfaces provided the best results. When the taxonomic level changed from order to subgroup, the purity decreased, whereas the values of the diversity indices increased. The highest purity and lowest diversity are observed at the order level, indicating a good quality map in terms of its purity, but reflecting only little soil diversity, thus with a low usage potential. On the other hand, soil maps at the level of subgroup illustrate high diversity and low purity, so that the predicted map units are highly uncertain. This map is also inappropriate for users. We introduced an index combining the diversity and purity which indicated that the best taxonomic level for soil mapping in the study area is the great group, with
A Covariance NMR Toolbox for MATLAB and OCTAVE
Short, Timothy; Alzapiedi, Leigh; Brüschweiler, Rafael; Snyder, David
2010-01-01
The Covariance NMR Toolbox is a new software suite that provides a streamlined implementation of covariance-based analysis of multi-dimensional NMR data. The Covariance NMR Toolbox uses the MATLAB or, alternatively, the freely available GNU OCTAVE computer language, providing a user-friendly environment in which to apply and explore covariance techniques. Covariance methods implemented in the toolbox described here include direct and indirect covariance processing, 4D covariance, generalized ...
On the Origin of Gravitational Lorentz Covariance
Khoury, Justin; Tolley, Andrew J
2013-01-01
We provide evidence that general relativity is the unique spatially covariant effective field theory of the transverse, traceless graviton degrees of freedom. The Lorentz covariance of general relativity, having not been assumed in our analysis, is thus plausibly interpreted as an accidental or emergent symmetry of the gravitational sector.
Treatment Effects with Many Covariates and Heteroskedasticity
DEFF Research Database (Denmark)
Cattaneo, Matias D.; Jansson, Michael; Newey, Whitney K.
propose a new heteroskedasticity consistent standard error formula that is fully automatic and robust to both (conditional) heteroskedasticity of unknown form and the inclusion of possibly many covariates. We apply our findings to three settings: (i) parametric linear models with many covariates, (ii...
Effect modification by time-varying covariates.
Robins, James M; Hernán, Miguel A; Rotnitzky, Andrea
2007-11-01
Marginal structural models (MSMs) allow estimation of effect modification by baseline covariates, but they are less useful for estimating effect modification by evolving time-varying covariates. Rather, structural nested models (SNMs) were specifically designed to estimate effect modification by time-varying covariates. In their paper, Petersen et al. (Am J Epidemiol 2007;166:985-993) describe history-adjusted MSMs as a generalized form of MSM and argue that history-adjusted MSMs allow a researcher to easily estimate effect modification by time-varying covariates. However, history-adjusted MSMs can result in logically incompatible parameter estimates and hence in contradictory substantive conclusions. Here the authors propose a more restrictive definition of history-adjusted MSMs than the one provided by Petersen et al. and compare the advantages and disadvantages of using history-adjusted MSMs, as opposed to SNMs, to examine effect modification by time-dependent covariates. PMID:17875581
Tunneling times with covariant measurements
Kiukas, J; Werner, R F; 10.1007/s10701-009-9275-z
2009-01-01
We consider the time delay of massive, non-relativistic, one-dimensional particles due to a tunneling potential. In this setting the well-known Hartman effect asserts that often the sub-ensemble of particles going through the tunnel seems to cross the tunnel region instantaneously. An obstacle to the utilization of this effect for getting faster signals is the exponential damping by the tunnel, so there seems to be a trade-off between speedup and intensity. In this paper we prove that this trade-off is never in favor of faster signals: the probability for a signal to reach its destination before some deadline is always reduced by the tunnel, for arbitrary incoming states, arbitrary positive and compactly supported tunnel potentials, and arbitrary detectors. More specifically, we show this for several different ways to define ``the same incoming state'' and ''the same detector'' when comparing the settings with and without tunnel potential. The arrival time measurements are expressed in the time-covariant appr...
Acuicultura Insostenible en Chile (Unsustainable aquaculture in Chile
Directory of Open Access Journals (Sweden)
Sommer, Marcos
2009-03-01
Full Text Available ResumenLa acuicultura en Chile sólo será alternativa a la pesca si se consigue llevar su producción a parámetros de sostenibilidad, no solamente económica sino, fundamentalmente, ambiental. Con un esfuerzo dirigido hacia medidas legislativas y de control, e investigación aplicada, podríamos acercarnos a una acuicultura ambientalmente sostenible.
FANTOM: Functional and taxonomic analysis of metagenomes
Directory of Open Access Journals (Sweden)
Sanli Kemal
2013-02-01
Full Text Available Abstract Background Interpretation of quantitative metagenomics data is important for our understanding of ecosystem functioning and assessing differences between various environmental samples. There is a need for an easy to use tool to explore the often complex metagenomics data in taxonomic and functional context. Results Here we introduce FANTOM, a tool that allows for exploratory and comparative analysis of metagenomics abundance data integrated with metadata information and biological databases. Importantly, FANTOM can make use of any hierarchical database and it comes supplied with NCBI taxonomic hierarchies as well as KEGG Orthology, COG, PFAM and TIGRFAM databases. Conclusions The software is implemented in Python, is platform independent, and is available at http://www.sysbio.se/Fantom.
Lactobacillus species: taxonomic complexity and controversial susceptibilities.
Goldstein, Ellie J C; Tyrrell, Kerin L; Citron, Diane M
2015-05-15
The genus Lactobacillus is a taxonomically complex and is composed of over 170 species that cannot be easily differentiated phenotypically and often require molecular identification. Although they are part of the normal human gastrointestinal and vaginal flora, they can also be occasional human pathogens. They are extensively used in a variety of commercial products including probiotics. Their antimicrobial susceptibilities are poorly defined in part because of their taxonomic complexity and are compounded by the different methods recommended by Clinical Laboratory Standards Institute and International Dairy Foundation. Their use as probiotics for prevention of Clostridium difficile infection is prevalent among consumers worldwide but raises the question of will the use of any concurrent antibiotic effect their ability to survive. Lactobacillus species are generally acid resistant and are able to survive ingestion. They are generally resistant to metronidazole, aminoglycosides and ciprofloxacin with L. acidophilus being susceptible to penicillin and vancomycin, whereas L. rhamnosus and L. casei are resistant to metronidazole and vancomycin. PMID:25922408
Lactobacillus species: taxonomic complexity and controversial susceptibilities.
Goldstein, Ellie J C; Tyrrell, Kerin L; Citron, Diane M
2015-05-15
The genus Lactobacillus is a taxonomically complex and is composed of over 170 species that cannot be easily differentiated phenotypically and often require molecular identification. Although they are part of the normal human gastrointestinal and vaginal flora, they can also be occasional human pathogens. They are extensively used in a variety of commercial products including probiotics. Their antimicrobial susceptibilities are poorly defined in part because of their taxonomic complexity and are compounded by the different methods recommended by Clinical Laboratory Standards Institute and International Dairy Foundation. Their use as probiotics for prevention of Clostridium difficile infection is prevalent among consumers worldwide but raises the question of will the use of any concurrent antibiotic effect their ability to survive. Lactobacillus species are generally acid resistant and are able to survive ingestion. They are generally resistant to metronidazole, aminoglycosides and ciprofloxacin with L. acidophilus being susceptible to penicillin and vancomycin, whereas L. rhamnosus and L. casei are resistant to metronidazole and vancomycin.
Taxonomic counts of cognition in the wild
Lefebvre, Louis
2010-01-01
In 1985, Kummer & Goodall pleaded for an ecology of intelligence and proposed that innovations might be a good way to measure cognition in the wild. Counts of innovation per taxonomic group are now available in hundreds of avian and primate species, as are counts of tactical deception, tool use and social learning. Robust evidence suggests that innovation rate and its neural correlates allow birds and mammals to cope better with environmental change. The positive correlations between taxonomi...
Analogies and correspondences between variograms and covariance functions
Gneiting, Tilmann; Sasvári, Zoltán; Schlather, Martin
2001-01-01
Variograms and covariance functions are key tools in geostatistics. However, various properties, characterizations, and decomposition theorems have been established for covariance functions only. We present analogous results for variograms and explore the connections with covariance functions. Our findings include criteria for covariance functions on intervals, and we apply them to exponential models, fractional Brownian motion, and locally polynomial covariances. In part...
Socialisme i Chile efter Pinochet
DEFF Research Database (Denmark)
Cristoffanini, Pablo Rolando
2008-01-01
Chile bliver ofte præsenteret som et paradigme for resten af det latinamerikanske kontinent: Et land med høj økonomisk vækst og politisk stabilitet. Landet har endda haft to socialistiske præsidenter siden 2000, den sidste den første kvindelige præsident. Succeshistorien har en bagside: De...... socialistiske regeringer har accepteret et begrænset demokrati og videreført en nyliberal økonomisk politik, der har bragt dem på konfrontationskurs med massebevægelserne og isoleret Chile fra de andre lande i regionen, der søger integration og gensidig støøte. Udgivelsesdato: Februar...
[The epidemiological transition in Chile].
Albalá, C; Vio, F; Robledo, A; Icaza, G
1993-12-01
Aiming to describe the place that Chile has in the epidemiological transition, a descriptive study of the changes in demographic and epidemiological profiles of the country during the last 30 years is presented. The important decrease in general and child mortality rates, that has lead to an increase in life expectancy and ageing of the population, is emphasized. A 82% reduction in the proportion of deaths among less than one year old children and a 62% increase in mortality among people 65 years or older is observed. In agreement with these changes, non transmissible chronic diseases appear as the principal cause of mortality (65% of all deaths). However, regarding morbidity, an increase in digestive infectious and sexually transmitted diseases and a decrease in immuno-preventable diseases, excepting measles, is noted. It is concluded that, according to mortality, Chile is in a post transition stage, but there is persistence of some infectious diseases, typical of a pre-transition stage. PMID:8085073
Miedo y represionpolitica en Chile
Amado M. Padilla; Lillian Comas Díaz
1987-01-01
This paper describes a human rights fact-finding mission to Chile concerned with the use of psychological techniques employed in offlcia- Uy sactioned torture and repressíon, Meetings and interviews were conducted with representatives of many organízatíons working with víctima of governrnental repression including the Chílean Psychological Assocíation. Fear and repression wene found to be widespread among all socioeconomic segments of the population. Physical and psychologic...
The covariate-adjusted frequency plot.
Holling, Heinz; Böhning, Walailuck; Böhning, Dankmar; Formann, Anton K
2016-04-01
Count data arise in numerous fields of interest. Analysis of these data frequently require distributional assumptions. Although the graphical display of a fitted model is straightforward in the univariate scenario, this becomes more complex if covariate information needs to be included into the model. Stratification is one way to proceed, but has its limitations if the covariate has many levels or the number of covariates is large. The article suggests a marginal method which works even in the case that all possible covariate combinations are different (i.e. no covariate combination occurs more than once). For each covariate combination the fitted model value is computed and then summed over the entire data set. The technique is quite general and works with all count distributional models as well as with all forms of covariate modelling. The article provides illustrations of the method for various situations and also shows that the proposed estimator as well as the empirical count frequency are consistent with respect to the same parameter.
Forecasting Covariance Matrices: A Mixed Frequency Approach
DEFF Research Database (Denmark)
Halbleib, Roxana; Voev, Valeri
This paper proposes a new method for forecasting covariance matrices of financial returns. The model mixes volatility forecasts from a dynamic model of daily realized volatilities estimated with high-frequency data with correlation forecasts based on daily data. This new approach allows...... for flexible dependence patterns for volatilities and correlations, and can be applied to covariance matrices of large dimensions. The separate modeling of volatility and correlation forecasts considerably reduces the estimation and measurement error implied by the joint estimation and modeling of covariance...... matrix dynamics. Our empirical results show that the new mixing approach provides superior forecasts compared to multivariate volatility specifications using single sources of information....
Estimation of Low-Rank Covariance Function
Koltchinskii, Vladimir; Lounici, Karim; Tsybakov, Alexander B.
2015-01-01
We consider the problem of estimating a low rank covariance function $K(t,u)$ of a Gaussian process $S(t), t\\in [0,1]$ based on $n$ i.i.d. copies of $S$ observed in a white noise. We suggest a new estimation procedure adapting simultaneously to the low rank structure and the smoothness of the covariance function. The new procedure is based on nuclear norm penalization and exhibits superior performances as compared to the sample covariance function by a polynomial factor in the sample size $n$...
Modular covariance, PCT, spin and statistics
Guido, D
1995-01-01
The notion of modular covariance is reviewed and the reconstruction of the Poincar\\'e group extended to the low-dimensional case. The relations with the PCT symmetry and the Spin and Statistics theorem are described.
Covariant Vertex Operators for Cosmic Strings
Skliros, Dimitri P
2009-01-01
We construct covariant vertex operators for high mass bosonic F-string states and present the first realization of coherent open and closed string states in the covariant gauge. We relate a suitable subclass of the vertex operators constructed to both general and specific classical string solutions. In the process we derive the explicit map from light-cone gauge string states (where the physical interpretation is more direct) to the fully covariant normal ordered vertex operators (where the physical interpretation has hitherto been somewhat obscured by the presence of ghosts, but which is nevertheless more appropriate for amplitude computations in general) by making use of DDF operators. In addition to coherent states, we construct quasi-classical states, in particular monomial and polynomial vertex operators in both lightcone and covariant gauge which lie beyond the leading Regge trajectory and extract via factorization vertex operators produced in tachyon-tachyon, tachyon-massless and massless-massless stri...
Geometric methods for estimation of structured covariances
Ning, Lipeng; Georgiou, Tryphon
2011-01-01
We consider problems of estimation of structured covariance matrices, and in particular of matrices with a Toeplitz structure. We follow a geometric viewpoint that is based on some suitable notion of distance. To this end, we overview and compare several alternatives metrics and divergence measures. We advocate a specific one which represents the Wasserstein distance between the corresponding Gaussians distributions and show that it coincides with the so-called Bures/Hellinger distance between covariance matrices as well. Most importantly, besides the physically appealing interpretation, computation of the metric requires solving a linear matrix inequality (LMI). As a consequence, computations scale nicely for problems involving large covariance matrices, and linear prior constraints on the covariance structure are easy to handle. We compare this transportation/Bures/Hellinger metric with the maximum likelihood and the Burg methods as to their performance with regard to estimation of power spectra with spectr...
The Covariant Picard Groupoid in Differential Geometry
Waldmann, Stefan
2005-01-01
In this article we discuss some general results on the covariant Picard groupoid in the context of differential geometry and interpret the problem of lifting Lie algebra actions to line bundles in the Picard groupoid approach.
Characteristic Polynomials of Sample Covariance Matrices
Kösters, Holger
2009-01-01
We investigate the second-order correlation function of the characteristic polynomial of a sample covariance matrix. Starting from an explicit formula for the generating function, we re-obtain several well-known kernels from random matrix theory.
Covariance Spectroscopy for Fissile Material Detection
Energy Technology Data Exchange (ETDEWEB)
Rusty Trainham, Jim Tinsley, Paul Hurley, Ray Keegan
2009-06-02
Nuclear fission produces multiple prompt neutrons and gammas at each fission event. The resulting daughter nuclei continue to emit delayed radiation as neutrons boil off, beta decay occurs, etc. All of the radiations are causally connected, and therefore correlated. The correlations are generally positive, but when different decay channels compete, so that some radiations tend to exclude others, negative correlations could also be observed. A similar problem of reduced complexity is that of cascades radiation, whereby a simple radioactive decay produces two or more correlated gamma rays at each decay. Covariance is the usual means for measuring correlation, and techniques of covariance mapping may be useful to produce distinct signatures of special nuclear materials (SNM). A covariance measurement can also be used to filter data streams because uncorrelated signals are largely rejected. The technique is generally more effective than a coincidence measurement. In this poster, we concentrate on cascades and the covariance filtering problem.
Evaluation of covariance for fission neutron spectra
Energy Technology Data Exchange (ETDEWEB)
Kawano, Toshihiko; Nakashima, Hideki [Kyushu Univ., Fukuoka (Japan); Ohsawa, Takaaki; Shibata, Keiichi
1999-02-01
A covariance evaluation system for the evaluated nuclear data library JENDL-3.2 was established, and the covariance data for fission neutron spectra of {sup 233}U, {sup 235}U, {sup 238}U, {sup 239}Pu were evaluated. Two methods were employed to evaluate the covariance. One is based on the experimental data, and the other is based on a model calculation including some kinds of renormalizations. The latter technique was adopted for the covariance evaluation of the fission neutron spectra in JENDL-3.2. We performed an adjustment of the evaluated fission neutron spectrum of {sup 235}U using the spectrum averaged cross sections for the {sup 27}Al(n, p), {sup 46,47,48}Ti(n, p), {sup 54,56}Fe(n, p), {sup 58}Ni(n, p), {sup 90}Zr(n, 2n) reactions. The adjusted spectrum integrated over energy was found to be unity. (author)
Directory of Open Access Journals (Sweden)
Labarca, R.
2016-06-01
Full Text Available This paper contextualizes, describes and taxonomically assigned cranial and dental Gomphotheriidae materials from the El Trebal 1, late Pleistocene form central Chile. Starting from metric and morphological variables fossils are included in Stegomastodon platensisStegomastodon platensis. Taxonomic implications of this finding as well as some regional paleoenvironmental history are discussed.El presente trabajo contextualiza, describe, y asigna taxonómicamente los materiales craneales y dentales de Gomphotheriidae provenientes del sitio El Trebal 1, Pleistoceno tardío de Chile central. A partir de variables métricas y morfológicas los fósiles son incluidos en Stegomastodon platensisStegomastodon platensis. Se discuten las implicancias taxonómicas de este hallazgo así como algunos antecedentes paleoambientales regionales.
Functional CLT for sample covariance matrices
Bai, Zhidong; Zhou, Wang; 10.3150/10-BEJ250
2010-01-01
Using Bernstein polynomial approximations, we prove the central limit theorem for linear spectral statistics of sample covariance matrices, indexed by a set of functions with continuous fourth order derivatives on an open interval including $[(1-\\sqrt{y})^2,(1+\\sqrt{y})^2]$, the support of the Mar\\u{c}enko--Pastur law. We also derive the explicit expressions for asymptotic mean and covariance functions.
Covariant action for type IIB supergravity
Sen, Ashoke
2016-07-01
Taking clues from the recent construction of the covariant action for type II and heterotic string field theories, we construct a manifestly Lorentz covariant action for type IIB supergravity, and discuss its gauge fixing maintaining manifest Lorentz invariance. The action contains a (non-gravitating) free 4-form field besides the usual fields of type IIB supergravity. This free field, being completely decoupled from the interacting sector, has no physical consequence.
Covariate analysis of bivariate survival data
Energy Technology Data Exchange (ETDEWEB)
Bennett, L.E.
1992-01-01
The methods developed are used to analyze the effects of covariates on bivariate survival data when censoring and ties are present. The proposed method provides models for bivariate survival data that include differential covariate effects and censored observations. The proposed models are based on an extension of the univariate Buckley-James estimators which replace censored data points by their expected values, conditional on the censoring time and the covariates. For the bivariate situation, it is necessary to determine the expectation of the failure times for one component conditional on the failure or censoring time of the other component. Two different methods have been developed to estimate these expectations. In the semiparametric approach these expectations are determined from a modification of Burke's estimate of the bivariate empirical survival function. In the parametric approach censored data points are also replaced by their conditional expected values where the expected values are determined from a specified parametric distribution. The model estimation will be based on the revised data set, comprised of uncensored components and expected values for the censored components. The variance-covariance matrix for the estimated covariate parameters has also been derived for both the semiparametric and parametric methods. Data from the Demographic and Health Survey was analyzed by these methods. The two outcome variables are post-partum amenorrhea and breastfeeding; education and parity were used as the covariates. Both the covariate parameter estimates and the variance-covariance estimates for the semiparametric and parametric models will be compared. In addition, a multivariate test statistic was used in the semiparametric model to examine contrasts. The significance of the statistic was determined from a bootstrap distribution of the test statistic.
Taxonomical developments in the family Polyomaviridae.
Johne, Reimar; Buck, Christopher B; Allander, Tobias; Atwood, Walter J; Garcea, Robert L; Imperiale, Michael J; Major, Eugene O; Ramqvist, Torbjorn; Norkin, Leonard C
2011-09-01
The Polyomaviridae Study Group of the International Committee on Taxonomy of Viruses (ICTV) has recommended several taxonomical revisions, as follows: The family Polyomaviridae, which is currently constituted as a single genus (Polyomavirus), will be comprised of three genera: two containing mammalian viruses and one containing avian viruses. The two mammalian genera will be designated Orthopolyomavirus and Wukipolyomavirus, and the avian genus will be named Avipolyomavirus. These genera will be created by the redistribution of species from the current single genus (Polyomavirus) and by the inclusion of several new species. In addition, the names of several species will be changed to reflect current usage.
Representations of Inverse Covariances by Differential Operators
Institute of Scientific and Technical Information of China (English)
Qin XU
2005-01-01
In the cost function of three- or four-dimensional variational data assimilation, each term is weighted by the inverse of its associated error covariance matrix and the background error covariance matrix is usually much larger than the other covariance matrices. Although the background error covariances are traditionally normalized and parameterized by simple smooth homogeneous correlation functions, the covariance matrices constructed from these correlation functions are often too large to be inverted or even manipulated. It is thus desirable to find direct representations of the inverses of background errorcorrelations. This problem is studied in this paper. In particular, it is shown that the background term can be written into ∫ dx|Dv(x)|2, that is, a squared L2 norm of a vector differential operator D, called the D-operator, applied to the field of analysis increment v(x). For autoregressive correlation functions, the Doperators are of finite orders. For Gaussian correlation functions, the D-operators are of infinite order. For practical applications, the Gaussian D-operators must be truncated to finite orders. The truncation errors are found to be small even when the Gaussian D-operators are truncated to low orders. With a truncated D-operator, the background term can be easily constructed with neither inversion nor direct calculation of the covariance matrix. D-operators are also derived for non-Gaussian correlations and transformed into non-isotropic forms.
Sequential BART for imputation of missing covariates.
Xu, Dandan; Daniels, Michael J; Winterstein, Almut G
2016-07-01
To conduct comparative effectiveness research using electronic health records (EHR), many covariates are typically needed to adjust for selection and confounding biases. Unfortunately, it is typical to have missingness in these covariates. Just using cases with complete covariates will result in considerable efficiency losses and likely bias. Here, we consider the covariates missing at random with missing data mechanism either depending on the response or not. Standard methods for multiple imputation can either fail to capture nonlinear relationships or suffer from the incompatibility and uncongeniality issues. We explore a flexible Bayesian nonparametric approach to impute the missing covariates, which involves factoring the joint distribution of the covariates with missingness into a set of sequential conditionals and applying Bayesian additive regression trees to model each of these univariate conditionals. Using data augmentation, the posterior for each conditional can be sampled simultaneously. We provide details on the computational algorithm and make comparisons to other methods, including parametric sequential imputation and two versions of multiple imputation by chained equations. We illustrate the proposed approach on EHR data from an affiliated tertiary care institution to examine factors related to hyperglycemia. PMID:26980459
Sistema de salud de Chile The health system of Chile
Víctor Becerril-Montekio; Juan de Dios Reyes; Annick Manuel
2011-01-01
En este trabajo se describe el sistema de salud de Chile, incluyendo su estructura, financiamiento, beneficiarios y recursos físicos, materiales y humanos de los que dispone. Este sistema está compuesto por dos sectores, público y privado. El sector público está formado por todos los organismos que constituyen el Sistema Nacional de Servicios de Salud y cubre aproximadamente a 70% de la población, incluyendo a los pobres del campo y las ciudades, la clase media baja y los jubilados, así como ...
Chile : Household Risk Management and Social Protection
World Bank, (WB)
2004-01-01
This report is part of the World Bank's advisory and analytical assistance to the Government of Chile. The report examines whether Chile has a social protection "system" - broadly defined to include policy interventions, public institutions, and the regulation of private institutions that lower the welfare costs of adverse shocks to income from job loss and extended unemployment, health ep...
Rising Expectations in Brazil and Chile
Elacqua, Gregory; Alves, Fatima
2014-01-01
Two themes connect Brazil and Chile: one is economic success; the other is social unrest. Protests rocked cities across Brazil in June 2013, and in Chile, recent student protests turned violent. Yet living conditions in both nations are better now than they've ever been. Successful economic and social reforms over the last two decades have…
Covariance Modifications to Subspace Bases
Energy Technology Data Exchange (ETDEWEB)
Harris, D B
2008-11-19
Adaptive signal processing algorithms that rely upon representations of signal and noise subspaces often require updates to those representations when new data become available. Subspace representations frequently are estimated from available data with singular value (SVD) decompositions. Subspace updates require modifications to these decompositions. Updates can be performed inexpensively provided they are low-rank. A substantial literature on SVD updates exists, frequently focusing on rank-1 updates (see e.g. [Karasalo, 1986; Comon and Golub, 1990, Badeau, 2004]). In these methods, data matrices are modified by addition or deletion of a row or column, or data covariance matrices are modified by addition of the outer product of a new vector. A recent paper by Brand [2006] provides a general and efficient method for arbitrary rank updates to an SVD. The purpose of this note is to describe a closely-related method for applications where right singular vectors are not required. This note also describes the SVD updates to a particular scenario of interest in seismic array signal processing. The particular application involve updating the wideband subspace representation used in seismic subspace detectors [Harris, 2006]. These subspace detectors generalize waveform correlation algorithms to detect signals that lie in a subspace of waveforms of dimension d {ge} 1. They potentially are of interest because they extend the range of waveform variation over which these sensitive detectors apply. Subspace detectors operate by projecting waveform data from a detection window into a subspace specified by a collection of orthonormal waveform basis vectors (referred to as the template). Subspace templates are constructed from a suite of normalized, aligned master event waveforms that may be acquired by a single sensor, a three-component sensor, an array of such sensors or a sensor network. The template design process entails constructing a data matrix whose columns contain the
Víctor Becerril-Montekio; Juan de Dios Reyes; Annick Manuel
2011-01-01
En este trabajo se describe el sistema de salud de Chile, incluyendo su estructura, financiamiento, beneficiarios y recursos físicos, materiales y humanos de los que dispone. Este sistema está compuesto por dos sectores, público y privado. El sector público está formado por todos los organismos que constituyen el Sistema Nacional de Servicios de Salud y cubre aproximadamente a 70% de la población, incluyendo a los pobres del campo y las ciudades, la clase media baja y los jubilados, así como ...
[Antimicrobial susceptibility in Chile 2012].
Cifuentes-D, Marcela; Silva, Francisco; García, Patricia; Bello, Helia; Briceño, Isabel; Calvo-A, Mario; Labarca, Jaime
2014-04-01
Bacteria antimicrobial resistance is an uncontrolled public health problem that progressively increases its magnitude and complexity. The Grupo Colaborativo de Resistencia, formed by a join of experts that represent 39 Chilean health institutions has been concerned with bacteria antimicrobial susceptibility in our country since 2008. In this document we present in vitro bacterial susceptibility accumulated during year 2012 belonging to 28 national health institutions that represent about 36% of hospital discharges in Chile. We consider of major importance to report periodically bacteria susceptibility so to keep the medical community updated to achieve target the empirical antimicrobial therapies and the control measures and prevention of the dissemination of multiresistant strains.
Directory of Open Access Journals (Sweden)
Alberdi, M. T.
2000-08-01
Full Text Available Mastodont fossil remains from Chile are described and discussed from a taxonomic point of view. A single species must be considered: Cuvieronius hyodon (Fischer for the Late Pleistocene of Chile. Some of its characteristics are analyzed and compared with those of other mastodons from different localities in South America. Paleoecological considerations are revised and potential migration routes from the north, towards the Chilean territory, are also discussed.Se describen y sitúan taxonómicamente los restos de mastodontes de las localidades chilenas. Se identifica una sola forma: Cuvieronius hyodon (Fischer para el Pleistoceno superior en Chile. Se analizan sus características y se comparan con aquellas de mastodontes de otras localidades de América del Sur. Asimismo se revisan consideraciones de tipo paleoecológico, y se discuten sus probables vías de migración desde el norte hacia el territorio chileno.
A Taxonomic Study of the Genus Myelochroa in South Korea
Jayalal, Udeni; Joshi, Santosh; Oh, Soon-Ok; Koh, Young Jin; Hur, Jae-Seoun
2012-01-01
Myelochroa (Asahina) Elix & Hale is a common foliose lichen genus found on the Korean Peninsula. Since it was first recorded nearly two decades ago, no detailed taxonomic or revisionary study of the genus has been conducted. Thus, the current study was conducted to carry out a detailed taxonomic and revisionary study of Myelochroa in South Korea. This study was based on specimens deposited in the Korean Lichen Research Institute (KoLRI). Detailed taxonomic studies and a literature review conf...
Nuclear data covariances in the Indian context
International Nuclear Information System (INIS)
The topic of covariances is recognized as an important part of several ongoing nuclear data science activities, since 2007, in the Nuclear Data Physics Centre of India (NDPCI). A Phase-1 project in collaboration with the Statistics department in Manipal University, Karnataka (Prof. K.M. Prasad and Prof. S. Nair) on nuclear data covariances was executed successfully during 2007-2011 period. In Phase-I, the NDPCI has conducted three national Theme meetings sponsored by the DAE-BRNS in 2008, 2010 and 2013 on nuclear data covariances. In Phase-1, the emphasis was on a thorough basic understanding of the concept of covariances including assigning uncertainties to experimental data in terms of partial errors and micro correlations, through a study and a detailed discussion of open literature. Towards the end of Phase-1, measurements and a first time covariance analysis of cross-sections for 58Ni (n, p) 58Co reaction measured in Mumbai Pelletron accelerator using 7Li (p,n) reactions as neutron source in the MeV energy region were performed under a PhD programme on nuclear data covariances in which enrolled are two students, Shri B.S. Shivashankar and Ms. Shanti Sheela. India is also successfully evolving a team of young researchers to code nuclear data of uncertainties, with the perspectives on covariances, in the IAEA-EXFOR format. A Phase-II DAE-BRNS-NDPCI proposal of project at Manipal has been submitted and the proposal is undergoing a peer-review at this time. In Phase-2, modern nuclear data evaluation techniques that including covariances will be further studied as a research and development effort, as a first time effort. These efforts include the use of techniques such as that of the Kalman filter. Presently, a 48 hours lecture series on treatment of errors and their propagation is being formulated under auspices of the Homi Bhabha National Institute. The talk describes the progress achieved thus far in the learning curve of the above-mentioned and exciting
Cross-covariance functions for multivariate geostatistics
Genton, Marc G.
2015-05-01
Continuously indexed datasets with multiple variables have become ubiquitous in the geophysical, ecological, environmental and climate sciences, and pose substantial analysis challenges to scientists and statisticians. For many years, scientists developed models that aimed at capturing the spatial behavior for an individual process; only within the last few decades has it become commonplace to model multiple processes jointly. The key difficulty is in specifying the cross-covariance function, that is, the function responsible for the relationship between distinct variables. Indeed, these cross-covariance functions must be chosen to be consistent with marginal covariance functions in such a way that the second-order structure always yields a nonnegative definite covariance matrix. We review the main approaches to building cross-covariance models, including the linear model of coregionalization, convolution methods, the multivariate Matérn and nonstationary and space-time extensions of these among others. We additionally cover specialized constructions, including those designed for asymmetry, compact support and spherical domains, with a review of physics-constrained models. We illustrate select models on a bivariate regional climate model output example for temperature and pressure, along with a bivariate minimum and maximum temperature observational dataset; we compare models by likelihood value as well as via cross-validation co-kriging studies. The article closes with a discussion of unsolved problems. © Institute of Mathematical Statistics, 2015.
Activities on covariance estimation in Japanese Nuclear Data Committee
Energy Technology Data Exchange (ETDEWEB)
Shibata, Keiichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1997-03-01
Described are activities on covariance estimation in the Japanese Nuclear Data Committee. Covariances are obtained from measurements by using the least-squares methods. A simultaneous evaluation was performed to deduce covariances of fission cross sections of U and Pu isotopes. A code system, KALMAN, is used to estimate covariances of nuclear model calculations from uncertainties in model parameters. (author)
TaxMan: a taxonomic database manager
Directory of Open Access Journals (Sweden)
Blaxter Mark
2006-12-01
Full Text Available Abstract Background Phylogenetic analysis of large, multiple-gene datasets, assembled from public sequence databases, is rapidly becoming a popular way to approach difficult phylogenetic problems. Supermatrices (concatenated multiple sequence alignments of multiple genes can yield more phylogenetic signal than individual genes. However, manually assembling such datasets for a large taxonomic group is time-consuming and error-prone. Additionally, sequence curation, alignment and assessment of the results of phylogenetic analysis are made particularly difficult by the potential for a given gene in a given species to be unrepresented, or to be represented by multiple or partial sequences. We have developed a software package, TaxMan, that largely automates the processes of sequence acquisition, consensus building, alignment and taxon selection to facilitate this type of phylogenetic study. Results TaxMan uses freely available tools to allow rapid assembly, storage and analysis of large, aligned DNA and protein sequence datasets for user-defined sets of species and genes. The user provides GenBank format files and a list of gene names and synonyms for the loci to analyse. Sequences are extracted from the GenBank files on the basis of annotation and sequence similarity. Consensus sequences are built automatically. Alignment is carried out (where possible, at the protein level and aligned sequences are stored in a database. TaxMan can automatically determine the best subset of taxa to examine phylogeny at a given taxonomic level. By using the stored aligned sequences, large concatenated multiple sequence alignments can be generated rapidly for a subset and output in analysis-ready file formats. Trees resulting from phylogenetic analysis can be stored and compared with a reference taxonomy. Conclusion TaxMan allows rapid automated assembly of a multigene datasets of aligned sequences for large taxonomic groups. By extracting sequences on the basis of
Miedo y represionpolitica en Chile
Directory of Open Access Journals (Sweden)
Amado M. Padilla
1987-01-01
Full Text Available This paper describes a human rights fact-finding mission to Chile concerned with the use of psychological techniques employed in offlcia- Uy sactioned torture and repressíon, Meetings and interviews were conducted with representatives of many organízatíons working with víctima of governrnental repression including the Chílean Psychological Assocíation. Fear and repression wene found to be widespread among all socioeconomic segments of the population. Physical and psychological abuses directed at individuals are díscussed, Psychological techníques used in the control of social groups such as intimidation, control of information, and community destabilization are also described. It is concluded that violations of human rigths are a reality in Chile. Ways to support the work of Chilean psychologists must be sought sínce the damaging eonsequences of officially sanctioned repressíon are wid.espread, and resources are minimal.
Energy Technology Data Exchange (ETDEWEB)
1988-11-18
In recent years, a new emphasis has been placed on increasing solid fuel availability in Chile, to reach the northern mining operations where demand for power is soaring. The south of the country is well served by hydroelectric power plants (2.3 million kW). The coal industry has doubled its capacity to cope with increased copper production - the Tocopilla power plant at the Chuquicamata copper mine has been converted from oil to coal - and there has been a major investment programme in the steel industry. In 1986, 1.4 million tons of coal was mined, mostly from the Provinces of Concepcion and Arauco, the remainder from Valdivia. Since then, 70 million US dollars has been invested by COCAR SA in the Pecket deposit near Punta Arenas. Coal from Pecket should cost around 26 dollars/t compared with 60 dollars/t for underground coal. It should support an expanded coal market in Chile and may also be able to compete in the Brazilian and Argentine markets. Reserves are estimated at over 200 Mt. Petroleum reserves in Tierra del Fuego are nearly exhausted; seismic surveys in the Atacama desert are promising.
Directory of Open Access Journals (Sweden)
MATÍAS MEZA-LOPEHANDÍA
2011-06-01
Full Text Available El problema de la desigualdad en Chile ha sido abordado desde diferentes puntos de vista como la cuestión de la distribución de la riqueza o el acceso a los derechos sociales. Es este trabajo se observa el mismo problema pero desde la perspectiva recientemente esbozada por los movimientos sociales: la del racismo ambiental o la desigual distribución de los deshechos del desarrollo y el consumo. De esta manera se revisan sucintamente los principales conflictos que han surgido en el último tiempo a lo largo del país entre empresas públicas y privadas y comunidades locales y originarias. Así mismo se examinan las formas de organización que estas últimas han asumido y el estado actual de articulación entre ellas. De la revisión de la situación se concluye que estamos ante el surgimiento de un actor de nuevo tipo, que surge de las contradicciones del Chile neoliberal y que se diferencia del movimiento ecologista por vincular sus reivindicaciones a la defensa del territorio y al derecho a la autodeterminación de los pueblos.
2007-01-01
The President of Chile, Michelle Bachelet, in the ATLAS cavern with, from left to right, Peter Jenni, ATLAS Spokesman, Vivian Heyl, CONICYT President, and Robert Aymar, CERN Director-General. Robert Aymar, CERN Director-General, and Vivian Heyl, CONICYT President, signing a cooperation agreement between CERN and Chile’s Comisión Nacional de Investigación Científica y Tecnológica (CONICYT).The President of Chile, Michelle Bachelet, paid a visit to CERN during her three-day tour of Switzerland. The charismatic Michelle Bachelet and her large delegation were greeted by the CERN Director-General and then taken to see the ATLAS experiment and the LHC. She also took time to meet the Chilean community working at CERN, comprising several physicists in the Theory Group and the ATLAS experiment. The meeting was followed by the signing of a cooperation agreement between CERN and Chile’s Comisión Nacional de Investigación Científi...
Accurate covariance estimation of galaxy-galaxy weak lensing: limitations of jackknife covariance
Shirasaki, Masato; Miyatake, Hironao; Takahashi, Ryuichi; Hamana, Takashi; Nishimichi, Takahiro; Murata, Ryoma
2016-01-01
We develop a method to simulate galaxy-galaxy weak lensing by utilizing all-sky, light-cone simulations. We populate a real catalog of source galaxies into a light-cone simulation realization, simulate the lensing effect on each galaxy, and then identify lensing halos that are considered to host galaxies or clusters of interest. We use the mock catalog to study the error covariance matrix of galaxy-galaxy weak lensing and find that the super-sample covariance (SSC), which arises from density fluctuations with length scales comparable with or greater than a size of survey area, gives a dominant source of the sample variance. We then compare the full covariance with the jackknife (JK) covariance, the method that estimates the covariance from the resamples of the data itself. We show that, although the JK method gives an unbiased estimator of the covariance in the shot noise or Gaussian regime, it always over-estimates the true covariance in the sample variance regime, because the JK covariance turns out to be a...
Progress on Nuclear Data Covariances: AFCI-1.2 Covariance Library
Energy Technology Data Exchange (ETDEWEB)
Oblozinsky,P.; Oblozinsky,P.; Mattoon,C.M.; Herman,M.; Mughabghab,S.F.; Pigni,M.T.; Talou,P.; Hale,G.M.; Kahler,A.C.; Kawano,T.; Little,R.C.; Young,P.G
2009-09-28
Improved neutron cross section covariances were produced for 110 materials including 12 light nuclei (coolants and moderators), 78 structural materials and fission products, and 20 actinides. Improved covariances were organized into AFCI-1.2 covariance library in 33-energy groups, from 10{sup -5} eV to 19.6 MeV. BNL contributed improved covariance data for the following materials: {sup 23}Na and {sup 55}Mn where more detailed evaluation was done; improvements in major structural materials {sup 52}Cr, {sup 56}Fe and {sup 58}Ni; improved estimates for remaining structural materials and fission products; improved covariances for 14 minor actinides, and estimates of mubar covariances for {sup 23}Na and {sup 56}Fe. LANL contributed improved covariance data for {sup 235}U and {sup 239}Pu including prompt neutron fission spectra and completely new evaluation for {sup 240}Pu. New R-matrix evaluation for {sup 16}O including mubar covariances is under completion. BNL assembled the library and performed basic testing using improved procedures including inspection of uncertainty and correlation plots for each material. The AFCI-1.2 library was released to ANL and INL in August 2009.
A novel algorithm for establishing taxonomic relation of Chinese ontology
Institute of Scientific and Technical Information of China (English)
PEI Bing-zhen; CHEN Xiao-rong; HU Yi; LU Ru-zhan
2009-01-01
Both a general domain-independent bottom-up multi-level model and an algorithm for establishing the taxonomic relation of Chinese ontology are proposed. The model consists of extracting domain vocabularies and establishing taxonomic relation, with the consideration of characteristics unique to Chinese natural language. By establishing the semantic forests of domain vocabularies and then using the existing semantic dictionary or ma-chine-readable dictionary (MRD), the proposed algorithm can integrate these semantic forests together to estab-lish the taxonomic relation. Experimental results show that the proposed algorithm is feasible and effective in es-tablishing the integrated taxonomic relation among domain vocabularies and concepts.
TIPP: taxonomic identification and phylogenetic profiling
Nguyen, Nam-phuong; Mirarab, Siavash; Liu, Bo; Pop, Mihai; Warnow, Tandy
2014-01-01
Motivation: Abundance profiling (also called ‘phylogenetic profiling’) is a crucial step in understanding the diversity of a metagenomic sample, and one of the basic techniques used for this is taxonomic identification of the metagenomic reads. Results: We present taxon identification and phylogenetic profiling (TIPP), a new marker-based taxon identification and abundance profiling method. TIPP combines SAT\\'e-enabled phylogenetic placement a phylogenetic placement method, with statistical techniques to control the classification precision and recall, and results in improved abundance profiles. TIPP is highly accurate even in the presence of high indel errors and novel genomes, and matches or improves on previous approaches, including NBC, mOTU, PhymmBL, MetaPhyler and MetaPhlAn. Availability and implementation: Software and supplementary materials are available at http://www.cs.utexas.edu/users/phylo/software/sepp/tipp-submission/. Contact: warnow@illinois.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25359891
Taxonomic etymology – in search of inspiration
Directory of Open Access Journals (Sweden)
Piotr Jozwiak
2015-07-01
Full Text Available We present a review of the etymology of zoological taxonomic names with emphasis on the most unusual examples. The names were divided into several categories, starting from the most common – given after morphological features – through inspiration from mythology, legends, and classic literature but also from fictional and nonfictional pop-culture characters (e.g., music, movies or cartoons, science, and politics. A separate category includes zoological names created using word-play and figures of speech such as tautonyms, acronyms, anagrams, and palindromes. Our intention was to give an overview of possibilities of how and where taxonomists can find the inspirations that will be consistent with the ICZN rules and generate more detail afterthought about the naming process itself, the meaningful character of naming, as well as the recognition and understanding of names.
Taxonomic etymology - in search of inspiration.
Jóźwiak, Piotr; Rewicz, Tomasz; Pabis, Krzysztof
2015-01-01
We present a review of the etymology of zoological taxonomic names with emphasis on the most unusual examples. The names were divided into several categories, starting from the most common - given after morphological features - through inspiration from mythology, legends, and classic literature but also from fictional and nonfictional pop-culture characters (e.g., music, movies or cartoons), science, and politics. A separate category includes zoological names created using word-play and figures of speech such as tautonyms, acronyms, anagrams, and palindromes. Our intention was to give an overview of possibilities of how and where taxonomists can find the inspirations that will be consistent with the ICZN rules and generate more detail afterthought about the naming process itself, the meaningful character of naming, as well as the recognition and understanding of names. PMID:26257573
Constanza J Letelier; Daniel E Núñez; Ricardo J Rey
2011-01-01
Se estableció una taxonomía de personas con diabetes tipo 2 basada en sus representaciones de enfermedad. Para ello se realizó un análisis de conglomerados con las respuestas de una muestra de conveniencia de 103 adultos de atención primaria de salud de la zona central de Chile, los que completaron la escala IPQ-R. Este análisis arrojó 3 grupos de pacientes, denominados Preocupado, Desesperanzado y Negador. El primero confía en los procedimientos para atenuar los efectos de la enfermedad. El ...
Manifest Covariant Hamiltonian Theory of General Relativity
Cremaschini, Claudio
2016-01-01
The problem of formulating a manifest covariant Hamiltonian theory of General Relativity in the presence of source fields is addressed, by extending the so-called "DeDonder-Weyl" formalism to the treatment of classical fields in curved space-time. The theory is based on a synchronous variational principle for the Einstein equation, formulated in terms of superabundant variables. The technique permits one to determine the continuum covariant Hamiltonian structure associated with the Einstein equation. The corresponding continuum Poisson bracket representation is also determined. The theory relies on first-principles, in the sense that the conclusions are reached in the framework of a non-perturbative covariant approach, which allows one to preserve both the 4-scalar nature of Lagrangian and Hamiltonian densities as well as the gauge invariance property of the theory.
Flexible taxonomic assignment of ambiguous sequencing reads
Directory of Open Access Journals (Sweden)
Jansson Jesper
2011-01-01
Full Text Available Abstract Background To characterize the diversity of bacterial populations in metagenomic studies, sequencing reads need to be accurately assigned to taxonomic units in a given reference taxonomy. Reads that cannot be reliably assigned to a unique leaf in the taxonomy (ambiguous reads are typically assigned to the lowest common ancestor of the set of species that match it. This introduces a potentially severe error in the estimation of bacteria present in the sample due to false positives, since all species in the subtree rooted at the ancestor are implicitly assigned to the read even though many of them may not match it. Results We present a method that maps each read to a node in the taxonomy that minimizes a penalty score while balancing the relevance of precision and recall in the assignment through a parameter q. This mapping can be obtained in time linear in the number of matching sequences, because LCA queries to the reference taxonomy take constant time. When applied to six different metagenomic datasets, our algorithm produces different taxonomic distributions depending on whether coverage or precision is maximized. Including information on the quality of the reads reduces the number of unassigned reads but increases the number of ambiguous reads, stressing the relevance of our method. Finally, two measures of performance are described and results with a set of artificially generated datasets are discussed. Conclusions The assignment strategy of sequencing reads introduced in this paper is a versatile and a quick method to study bacterial communities. The bacterial composition of the analyzed samples can vary significantly depending on how ambiguous reads are assigned depending on the value of the q parameter. Validation of our results in an artificial dataset confirm that a combination of values of q produces the most accurate results.
Is Mining Still the Wage of Chile?
Directory of Open Access Journals (Sweden)
Luis Valenzuela
2004-04-01
Full Text Available – Historia de la minería del hierro en Chile, by Augusto Millán. Santiago: Editorial Universitaria, 1999. – Capital transnacional y trabajo. El desarrollo minero en Chile, by Rafael Agacino, Cristián González and Jorge Rojas. Santiago: Lom Ediciones, 1998. – Dilemas y debates en torno al cobre, by Patricio Meller. Santiago: Dolmen, 2002. – Royalty. Regalía o renta minera. Lo que solo Chile no cobra, by Jorge Lavandero Illanes. Santiago: Ediciones Lafken, 2003.
A covariant formulation of classical spinning particle
Cho, J H; Kim, J K; Jin-Ho Cho; Seungjoon Hyun; Jae-Kwan Kim
1994-01-01
Covariantly we reformulate the description of a spinning particle in terms of the which entails all possible constraints explicitly; all constraints can be obtained just from the Lagrangian. Furthermore, in this covariant reformulation, the Lorentz element is to be considered to evolve the momentum or spin component from an arbitrary fixed frame and not just from the particle rest frame. In distinction with the usual formulation, our system is directly comparable with the pseudo-classical formulation. We get a peculiar symmetry which resembles the supersymmetry of the pseudo-classical formulation.
Parametric number covariance in quantum chaotic spectra.
Vinayak; Kumar, Sandeep; Pandey, Akhilesh
2016-03-01
We study spectral parametric correlations in quantum chaotic systems and introduce the number covariance as a measure of such correlations. We derive analytic results for the classical random matrix ensembles using the binary correlation method and obtain compact expressions for the covariance. We illustrate the universality of this measure by presenting the spectral analysis of the quantum kicked rotors for the time-reversal invariant and time-reversal noninvariant cases. A local version of the parametric number variance introduced earlier is also investigated. PMID:27078354
Notes on Cosmic Censorship Conjecture revisited: Covariantly
Hamid, Aymen I M; Maharaj, Sunil D
2016-01-01
In this paper we study the dynamics of the trapped region using a frame independent semi-tetrad covariant formalism for general Locally Rotationally Symmetric (LRS) class II spacetimes. We covariantly prove some important geometrical results for the apparent horizon, and state the necessary and sufficient conditions for a singularity to be locally naked. These conditions bring out, for the first time in a quantitative and transparent manner, the importance of the Weyl curvature in deforming and delaying the trapped region during continual gravitational collapse, making the central singularity locally visible.
Modular invariance and covariant loop calculus
International Nuclear Information System (INIS)
The covariant loop calculus provides and efficient technique for computing explicit expressions for the density on moduli space corresponding to arbitrary (bosonic string) loop diagrams. Since modular invariance is not manifest, however, we carry out a detailed comparison with known explicit 2- and 3- loop results derived using analytic geometry (1 loop is known to be ok). We establish identity to 'high' order in some moduli and exactly in others. Agreement is found as a result of various non-trivial cancellations, in part related to number theory. We feel our results provide very strong support for the correctness of the covariant loop calculus approach. (orig.)
Parametric number covariance in quantum chaotic spectra.
Vinayak; Kumar, Sandeep; Pandey, Akhilesh
2016-03-01
We study spectral parametric correlations in quantum chaotic systems and introduce the number covariance as a measure of such correlations. We derive analytic results for the classical random matrix ensembles using the binary correlation method and obtain compact expressions for the covariance. We illustrate the universality of this measure by presenting the spectral analysis of the quantum kicked rotors for the time-reversal invariant and time-reversal noninvariant cases. A local version of the parametric number variance introduced earlier is also investigated.
A violation of the covariant entropy bound?
Masoumi, Ali
2014-01-01
Several arguments suggest that the entropy density at high energy density $\\rho$ should be given by the expression $s=K\\sqrt{\\rho/G}$, where $K$ is a constant of order unity. On the other hand the covariant entropy bound requires that the entropy on a light sheet be bounded by $A/4G$, where $A$ is the area of the boundary of the sheet. We find that in a suitably chosen cosmological geometry, the above expression for $s$ violates the covariant entropy bound. We consider different possible explanations for this fact; in particular the possibility that entropy bounds should be defined in terms of volumes of regions rather than areas of surfaces.
Directory of Open Access Journals (Sweden)
José Bengoa
2011-12-01
Full Text Available El Bicentenario de la República de Chile se conmemoró en el mes de septiembre del año 2010. Además de marcar un importante hito histórico, coincidió con un cambio político en el Gobierno del país, el que pasó de la Concertación de Partidos por la Democracia a la Alianza de partidos formada por la derecha chilena. Se cumplieron por tanto 20 años desde que en el año 1990 cambiara el Gobierno militar presidido por el general Pinochet. Ese largo tiempo, dos décadas, coincide con un período de políticas que el Estado ha implementado hacia los Pueblos Indígenas. El Proyecto “Conmemoraciones y Memorias Subalternas” ha realizado durante el año 2010 un conjunto de investigaciones de terreno y documentales tendientes a comprender del modo más objetivo y científico lo ocurrido en el período y por tanto la situación actual de las sociedades mapuches en sus complejas relaciones con la chilena.O Bicentenario da República do Chile comemorou-se no mês de Setembro do ano 2010. Junto com transformar-se num marco histórico, coincidiu com uma mudança política no Governo do país, que passou da Concertação de Partidos pela Democracia (centro-esquerda à Aliança de partidos formada pela direita chilena. Cumpriram-se por tanto 20 anos desde que em 1990 mudasse o Governo militar presidido pelo general Pinochet. Esse longo tempo, duas décadas, coincide com um período de políticas que o Estado implementou para com os Povos Indígenas. O Projeto “Comemorações e Memórias Subalternas” realizou durante o ano 2010 um conjunto de pesquisas de campo e documentais tendentes a compreender do modo mais objetivo e científico o ocorrido no período e, por tanto, a situação atual das sociedades mapuches em suas complexas relações com a chilena.The conmeration of the 200 years of the Independence of Chile was in September 2010. This year was also the political change from the Concertación de Partidos por la Democracia to the right
Brier, Matthew R; Mitra, Anish; McCarthy, John E; Ances, Beau M; Snyder, Abraham Z
2015-11-01
Functional connectivity refers to shared signals among brain regions and is typically assessed in a task free state. Functional connectivity commonly is quantified between signal pairs using Pearson correlation. However, resting-state fMRI is a multivariate process exhibiting a complicated covariance structure. Partial covariance assesses the unique variance shared between two brain regions excluding any widely shared variance, hence is appropriate for the analysis of multivariate fMRI datasets. However, calculation of partial covariance requires inversion of the covariance matrix, which, in most functional connectivity studies, is not invertible owing to rank deficiency. Here we apply Ledoit-Wolf shrinkage (L2 regularization) to invert the high dimensional BOLD covariance matrix. We investigate the network organization and brain-state dependence of partial covariance-based functional connectivity. Although RSNs are conventionally defined in terms of shared variance, removal of widely shared variance, surprisingly, improved the separation of RSNs in a spring embedded graphical model. This result suggests that pair-wise unique shared variance plays a heretofore unrecognized role in RSN covariance organization. In addition, application of partial correlation to fMRI data acquired in the eyes open vs. eyes closed states revealed focal changes in uniquely shared variance between the thalamus and visual cortices. This result suggests that partial correlation of resting state BOLD time series reflect functional processes in addition to structural connectivity.
Designing Multimedia Games for Young Children's Taxonomic Concept Development
Sung, Yao-Ting; Chang, Kuo-En; Lee, Meng-Da
2008-01-01
This study aimed to design and evaluate multimedia games which were based on the theories of children's development of taxonomic concepts. Factors that might affect children's classification skills, such as use of single physical characteristics of objects, competition between thematic and taxonomic relationships, difficulty in forming…
The MNHN taxonomic referential: state and ongoing developments
Bruckert, R.
2005-01-01
The relational database of taxonomic references developed in the Muséum National d’Histoire Naturelle (MNHN), in Paris, has been greatly improved. New names, principally synonyms, have been added to the database following four lines: (1) The referential has been improved taxonomically: type-species
Global pedodiversity, taxonomic distance, and the World Reference Base
Minasny, B.; McBratney, A.B.; Hartemink, A.E.
2010-01-01
This paper discusses the study of taxonomic distance and pedodiversity by (1) deriving taxonomic distances for the World Reference Base for Soil Resources (WRB), (2) calculating pedodiversity indices at the global scale using the soil map of the world at a scale 1:25M, and (3) comparing traditional
Village microgrids: The Chile project
Energy Technology Data Exchange (ETDEWEB)
Baring-Gould, E.I.
1997-12-01
This paper describes a village application in Chile. The objective was to demonstrate the technical, economic and institutional viability of renewable energy for rural electrification, as well as to allow local partners to gain experience with hybrid/renewable technology, resource assessment, system siting and operation. A micro-grid system is viewed as a small village system, up to 1200 kWh/day load with a 50 kW peak load. It can consist of components of wind, photovoltaic, batteries, and conventional generators. It is usually associated with a single generator source, and uses batteries to cover light day time loads. This paper looks at the experiences learned from this project with regard to all of the facets of planning and installing this project.
2010 Chile Earthquake Aftershock Response
Barientos, Sergio
2010-05-01
The Mw=8.8 earthquake off the coast of Chile on 27 February 2010 is the 5th largest megathrust earthquake ever to be recorded and provides an unprecedented opportunity to advance our understanding of megathrust earthquakes and associated phenomena. The 2010 Chile earthquake ruptured the Concepcion-Constitucion segment of the Nazca/South America plate boundary, south of the Central Chile region and triggered a tsunami along the coast. Following the 2010 earthquake, a very energetic aftershock sequence is being observed in an area that is 600 km along strike from Valparaiso to 150 km south of Concepcion. Within the first three weeks there were over 260 aftershocks with magnitude 5.0 or greater and 18 with magnitude 6.0 or greater (NEIC, USGS). The Concepcion-Constitucion segment lies immediately north of the rupture zone associated with the great magnitude 9.5 Chile earthquake, and south of the 1906 and the 1985 Valparaiso earthquakes. The last great subduction earthquake in the region dates back to the February 1835 event described by Darwin (1871). Since 1835, part of the region was affected in the north by the Talca earthquake in December 1928, interpreted as a shallow dipping thrust event, and by the Chillan earthquake (Mw 7.9, January 1939), a slab-pull intermediate depth earthquake. For the last 30 years, geodetic studies in this area were consistent with a fully coupled elastic loading of the subduction interface at depth; this led to identify the area as a mature seismic gap with potential for an earthquake of magnitude of the order 8.5 or several earthquakes of lesser magnitude. What was less expected was the partial rupturing of the 1985 segment toward north. Today, the 2010 earthquake raises some disturbing questions: Why and how the rupture terminated where it did at the northern end? How did the 2010 earthquake load the adjacent segment to the north and did the 1985 earthquake only partially ruptured the plate interface leaving loaded asperities since
Directory of Open Access Journals (Sweden)
SERGIO A CASTRO
2006-03-01
Full Text Available Rodulfo Amando Philippi (1808-1904 es considerado uno de los naturalistas más influyentes en el desarrollo de las Ciencias Naturales en Chile. Entre las actividades científicas que desempeñó en el país está su dedicación al trabajo taxonómico y sistemático, que lo llevó a describir numerosas especies de plantas, animales y hongos. En este artículo se determina su contribución al conocimiento del patrimonio biológico de Chile, cuantificando el número y proporción de las especies actualmente válidas. De las especies descritas, 1.670 son consideradas válidas. Esta cifra equivale al 5,8 % de la diversidad biológica reconocida para Chile. Su mayor aporte se concentra en plantas vasculares, donde se encuentran vigentes 1.017 especies, que representan el 19 % de la flora vascular de Chile. Mención especial requiere el caso de algunos grupos, tales como anfibios, fasmatódeos, dermápteros y dípteros, cuya actual diversidad incluye 14, 30, 16 y 9 % de las especies de descritas por Philippi, respectivamente. De acuerdo a lo anterior y en comparación con otros taxónomos, Rodulfo Amando Philippi es el autor del mayor número de descripciones de especies válidas de la biota de ChileRodulfo Amando Philippi (1808-1904 is considered one of most influential in the development of natural sciences in Chile. Among his scientific endeavors, he contributed taxonomic descriptions of the biological diversity of Chile, encompassing organisms in three living kingdoms: plants, animals and fungi. In this article we examine his contribution to the knowledge of the biological wealth of Chile, quantifying the number and proportion of current valid species he described. Our findings indicate that Philippi described 1,670 valid species, equivalent to 5.8 % of the recognized biological diversity for Chile. His greatest contributions were in vascular plants with 1,017 species descriptions, which represent 19 % of the vascular flora of Chile. Special
Biomonitoring air pollution in Chile
International Nuclear Information System (INIS)
Full text: Chile, in general, and Santiago, its capital city, in particular, has serious air pollution problems mainly in winter time when the pollutants could reach dangerous levels which might be detrimental to older people and children. A project was undertaken within the framework of a Co-ordinated Research Programme (CRP) supported by the International Atomic Energy Agency (IAEA) to carry out a long term study on atmospheric air pollution in Chile using biomonitors. The present paper describes the activities carried out within this CRP. The lichens, collected in clean areas (native forests), were transplanted to selected sites in Santiago and exposed during three and six months. At a second stage, samples of Tillandsia recurvata were collected in the Metropolitan Area. All samples were carefully cleaned, using only clean plastic materials, milled at liquid nitrogen temperature, freeze dried, re-homogenized and stored at low temperature until analysis. The samples were mainly analysed by INAA, RNAA SS-AAS and ASV. As part of the routine QA/QC programme, analytical laboratories involved in the project participated in intercomparison runs organized by the IAEA for the determination of trace and minor elements in two lichens samples. From the data and its subsequent mapping over the area under study, it was possible to identify places exposed to higher amounts of some elements. Of interest are also the correlations between several elements, perhaps indicating a given source of pollutants. The results indicate the usefulness of biomonitoring air pollution using lichens and Tillandsias, which, jointly with multielemental analytical techniques, such as NAA, open the possibility to study extensive areas without the infrastructure needed for conventional APM sample collection and at reduced costs. (author)
Directory of Open Access Journals (Sweden)
Luisa Baessolo
2010-08-01
Full Text Available Se reportan nuevas localidades para el anfípodo talítrido Orchestoidea tuberculata Nicolet 1849 en playas arenosas de la costa Chilena, extendiéndose el límite sur de distribución de la especie hasta el mar interior de la región de Aysén. Además, se discute la necesidad de intensificar los estudios taxonómicos con el objeto de descartar la presencia de más de una especie en el género.We report new localities of the talitrid amphipod Orchestoidea tuberculata Nicolet 1849 in sand beaches from the Chilean coast, extending the southern distributional limit of the species to the inner sea of Aysen Region, Chile. Besides, we discuss the need for more taxonomic studies, to exclude the presence of more than one species in the genus.
Report on the ESO Chile Science Days
West, Michael
2008-03-01
Science Days in Santiago are an annual gathering of ESO's geographically dispersed team in Chile to learn more about each other's research, to celebrate scientific achievements of the past year and to encourage new collaborations.
Surface Observations from Punta Arenas, Chile
National Oceanic and Atmospheric Administration, Department of Commerce — Surface Observations from Punta Arenas, in extreme southern Chile. WMO station ID 85934. Period of record 1896-1954. The original forms were scanned at the Museo...
1960 Puerto Montt, Valdivia, Chile Images
National Oceanic and Atmospheric Administration, Department of Commerce — On May 22, 1960, a Mw 9.5 earthquake, the largest earthquake ever instrumentally recorded, occurred in southern Chile. The series of earthquakes that followed...
Optimal covariate designs theory and applications
Das, Premadhis; Mandal, Nripes Kumar; Sinha, Bikas Kumar
2015-01-01
This book primarily addresses the optimality aspects of covariate designs. A covariate model is a combination of ANOVA and regression models. Optimal estimation of the parameters of the model using a suitable choice of designs is of great importance; as such choices allow experimenters to extract maximum information for the unknown model parameters. The main emphasis of this monograph is to start with an assumed covariate model in combination with some standard ANOVA set-ups such as CRD, RBD, BIBD, GDD, BTIBD, BPEBD, cross-over, multi-factor, split-plot and strip-plot designs, treatment control designs, etc. and discuss the nature and availability of optimal covariate designs. In some situations, optimal estimations of both ANOVA and the regression parameters are provided. Global optimality and D-optimality criteria are mainly used in selecting the design. The standard optimality results of both discrete and continuous set-ups have been adapted, and several novel combinatorial techniques have been applied for...
Covariates of Sesame Street Viewing by Preschoolers.
Spaner, Steven D.
A study was made of nine covariates as to their discriminating power between preschoolers who watch Sesame Street regularly and preschoolers who do not watch Sesame Street, Surveyed were 372 3-4 year old children on 9 variables. The nine variables were: race, socioeconomic status, number of siblings, child's birth order, maternal age, maternal…
Linear transformations of variance/covariance matrices
Parois, P.J.A.; Lutz, M.
2011-01-01
Many applications in crystallography require the use of linear transformations on parameters and their standard uncertainties. While the transformation of the parameters is textbook knowledge, the transformation of the standard uncertainties is more complicated and needs the full variance/covariance
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole Eiler; Shephard, N.
2004-01-01
This paper analyses multivariate high frequency financial data using realized covariation. We provide a new asymptotic distribution theory for standard methods such as regression, correlation analysis, and covariance. It will be based on a fixed interval of time (e.g., a day or week), allowing...... the number of high frequency returns during this period to go to infinity. Our analysis allows us to study how high frequency correlations, regressions, and covariances change through time. In particular we provide confidence intervals for each of these quantities....
Enterprise Surveys : Chile Country Profile 2010
World Bank; International Finance Corporation
2011-01-01
The Country Profile for Chile is based on data from the Enterprise Surveys conducted by the World Bank. The benchmarks include the averages for the group of countries in Latin America & Caribbean and the Chile income group. The enterprise surveys focus on the many factors that shape the decisions of firms to invest. These factors can be accommodating or constraining and play an important r...
Karyomorphology of Taiwanese Begonia (Begoniaceae): taxonomic implications.
Oginuma, Kazuo; Peng, Ching-I
2002-06-01
The karyomorphology of all 14 species of Taiwanese Begonia was investigated to elucidate their chromosome features and chromosomal evolution. Among all species investigated, differences in chromosome features are found in: (1) chromosome number 2 n = 22, 26, 36, 38, 52, 60, 64, 82, and (2) frequencies of chromosomes with secondary, tertiary, and/or small constrictions of polyploids, ranging from 23% to 63%, which is higher than the expected value of about 9%. It is suggested that after polyploidization from the diploid species (i.e., 2 n = 22 and frequencies of chromosomes with secondary, tertiary, and/or small constrictions of polyploids of about 9%), chromosome translocations occurred, followed by a decrease in chromosome number, and subsequently stabilized genomes were formed in various species in Taiwan. The karyomorphological evidence also suggested that the chromosome morphology has evolved in parallel in the begonias belonging to different sections in Taiwan. The variation in chromosomal features is more complex than the variation in floral and fruit morphologies. Karyomorphological data also supports the recognition of five new species in Taiwan: Begonia bouffordii, B. chuyunshanensis, B. pinglinensis, B. tengchiana, and B. wutaiana. Based on detailed karyomorphological analyses, the taxonomic implications, speciation, and chromosomal evolution in Taiwanese Begoniaare discussed.
Taxonomic status of Pelargonium reniforme Curt.
Directory of Open Access Journals (Sweden)
Janine E. Victor
2014-07-01
Full Text Available Background: Pelargonium reniforme Curt. is a morphologically variable species that many authors have attempted to split or combine. Confusion relating to the differences between the two subspecies currently included under P. reniforme has impeded attempts to assess their conservation status. Pelargonium reniforme is closely related to Pelargonium sidoides; the two species are indistinguishable when not flowering and their distributions overlap in some areas.Objectives: With this study, we aimed to clarify the taxonomic status of the two subspecies of P. reniforme, which has relevance in terms of their conservation status.Method: Leaf shape, petiole length, internode length and flower colour were assessed by studying herbarium specimens of the two subspecies of P. reniforme and specimens of P. sidoides. Living specimens of the two subspecies were also examined in their natural habitat.Results: The current investigation showed that the morphological characters used to distinguish the two subspecies of P. reniforme are too variable to separate them. Variation in some morphological characters may be related to environmental conditions.Conclusion: The recognition of the two subspecies of P. reniforme as distinct taxa is no longer justified.
Reference databases for taxonomic assignment in metagenomics.
Santamaria, Monica; Fosso, Bruno; Consiglio, Arianna; De Caro, Giorgio; Grillo, Giorgio; Licciulli, Flavio; Liuni, Sabino; Marzano, Marinella; Alonso-Alemany, Daniel; Valiente, Gabriel; Pesole, Graziano
2012-11-01
Metagenomics is providing an unprecedented access to the environmental microbial diversity. The amplicon-based metagenomics approach involves the PCR-targeted sequencing of a genetic locus fitting different features. Namely, it must be ubiquitous in the taxonomic range of interest, variable enough to discriminate between different species but flanked by highly conserved sequences, and of suitable size to be sequenced through next-generation platforms. The internal transcribed spacers 1 and 2 (ITS1 and ITS2) of the ribosomal DNA operon and one or more hyper-variable regions of 16S ribosomal RNA gene are typically used to identify fungal and bacterial species, respectively. In this context, reliable reference databases and taxonomies are crucial to assign amplicon sequence reads to the correct phylogenetic ranks. Several resources provide consistent phylogenetic classification of publicly available 16S ribosomal DNA sequences, whereas the state of ribosomal internal transcribed spacers reference databases is notably less advanced. In this review, we aim to give an overview of existing reference resources for both types of markers, highlighting strengths and possible shortcomings of their use for metagenomics purposes. Moreover, we present a new database, ITSoneDB, of well annotated and phylogenetically classified ITS1 sequences to be used as a reference collection in metagenomic studies of environmental fungal communities. ITSoneDB is available for download and browsing at http://itsonedb.ba.itb.cnr.it/.
Where Do Mexico and Chile Stand on Inclusive Education? Short Title: Inclusion in Mexico and Chile
García-Cedillo, Ismael; Romero-Contreras, Silvia; Ramos-Abadie, Liliana
2015-01-01
This paper discusses the background, current situation and challenges of educational integration and inclusive education in Mexico and Chile. These countries obtained similar low results on the academic achievement of their students (Mexico last and Chile second last) among OECD countries; and above average scores, among Latin-American countries.…
Healthcare Accessibility Shortfalls and Hospital Infrastructures in Chile
Directory of Open Access Journals (Sweden)
Stefano Mainardi
2009-03-01
Full Text Available To measure healthcare accessibility, a previous study formulated a stochastic cost frontier model, and applied it to distances of communal centres from nearest emergency hospitals in Chile. Based on a larger set of variables, this study re-estimates the distance threshold, and tests alternative specifications and distribution assumptions over the period 2000-05. Complementing the analysis, ordered probit regressions help examine the cross-commune allocation of hospitals with varying complexity of medical services. Thirdly, excess distance estimates are used with other covariates in tobit models of health sector infrastructure investments. Socio-economic, demographic and geophysical conditions, along with non-hospital healthcare facilities, explain spatial inequality of hospitals. Excess distances are robust to different model specifications and distribution assumptions, and do not appear to be compensated by standards of services of the nearest hospitals or new healthcare infrastructure and upgrading investments in support to the communes concerned. Communes with perceived inadequacy in timing of medical attention turn out to often register large location inefficiency too. For the most critical communal cases, the excess distance burden amounts.
Performance evaluation of sensor allocation algorithm based on covariance control
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
The covariance control capability of sensor allocation algorithms based on covariance control strategy is an important index to evaluate the performance of these algorithms. Owing to lack of standard performance metric indices to evaluate covariance control capability, sensor allocation ratio, etc, there are no guides to follow in the design procedure of sensor allocation algorithm in practical applications. To meet these demands, three quantified performance metric indices are presented, which are average covariance misadjustment quantity (ACMQ), average sensor allocation ratio (ASAR) and matrix metric influence factor (MMIF), where ACMQ, ASAR and MMIF quantify the covariance control capability, the usage of sensor resources and the robustness of sensor allocation algorithm, respectively. Meanwhile, a covariance adaptive sensor allocation algorithm based on a new objective function is proposed to improve the covariance control capability of the algorithm based on information gain. The experiment results show that the proposed algorithm have the advantage over the preceding sensor allocation algorithm in covariance control capability and robustness.
Covariant holography of a tachyonic accelerating universe
Energy Technology Data Exchange (ETDEWEB)
Rozas-Fernandez, Alberto [Consejo Superior de Investigaciones Cientificas, Instituto de Fisica Fundamental, Madrid (Spain); University of Portsmouth, Institute of Cosmology and Gravitation, Portsmouth (United Kingdom)
2014-08-15
We apply the holographic principle to a flat dark energy dominated Friedmann-Robertson-Walker spacetime filled with a tachyon scalar field with constant equation of state w = p/ρ, both for w > -1 and w < -1. By using a geometrical covariant procedure, which allows the construction of holographic hypersurfaces, we have obtained for each case the position of the preferred screen and have then compared these with those obtained by using the holographic dark energy model with the future event horizon as the infrared cutoff. In the phantom scenario, one of the two obtained holographic screens is placed on the big rip hypersurface, both for the covariant holographic formalism and the holographic phantom model. It is also analyzed whether the existence of these preferred screens allows a mathematically consistent formulation of fundamental theories based on the existence of an S-matrix at infinite distances. (orig.)
Covariant Gauge Fixing and Canonical Quantization
McKeon, D G C
2011-01-01
Theories that contain first class constraints possess gauge invariance which results in the necessity of altering the measure in the associated quantum mechanical path integral. If the path integral is derived from the canonical structure of the theory, then the choice of gauge conditions used in constructing Faddeev's measure cannot be covariant. This shortcoming is normally overcome either by using the "Faddeev-Popov" quantization procedure, or by the approach of Batalin-Fradkin-Fradkina-Vilkovisky, and then demonstrating that these approaches are equivalent to the path integral constructed from the canonical approach with Faddeev's measure. We propose in this paper an alternate way of defining the measure for the path integral when it is constructed using the canonical procedure for theories containing first class constraints and that this new approach can be used in conjunction with covariant gauges. This procedure follows the Faddeev-Popov approach, but rather than working with the form of the gauge tran...
Model selection for Poisson processes with covariates
Sart, Mathieu
2011-01-01
We observe $n$ inhomogeneous Poisson processes with covariates and aim at estimating their intensities. To handle this problem, we assume that the intensity of each Poisson process is of the form $s (\\cdot, x)$ where $x$ is the covariate and where $s$ is an unknown function. We propose a model selection approach where the models are used to approximate the multivariate function $s$. We show that our estimator satisfies an oracle-type inequality under very weak assumptions both on the intensities and the models. By using an Hellinger-type loss, we establish non-asymptotic risk bounds and specify them under various kind of assumptions on the target function $s$ such as being smooth or composite. Besides, we show that our estimation procedure is robust with respect to these assumptions.
Errors on errors - Estimating cosmological parameter covariance
Joachimi, Benjamin
2014-01-01
Current and forthcoming cosmological data analyses share the challenge of huge datasets alongside increasingly tight requirements on the precision and accuracy of extracted cosmological parameters. The community is becoming increasingly aware that these requirements not only apply to the central values of parameters but, equally important, also to the error bars. Due to non-linear effects in the astrophysics, the instrument, and the analysis pipeline, data covariance matrices are usually not well known a priori and need to be estimated from the data itself, or from suites of large simulations. In either case, the finite number of realisations available to determine data covariances introduces significant biases and additional variance in the errors on cosmological parameters in a standard likelihood analysis. Here, we review recent work on quantifying these biases and additional variances and discuss approaches to remedy these effects.
Covariance and the hierarchy of frame bundles
Estabrook, Frank B.
1987-01-01
This is an essay on the general concept of covariance, and its connection with the structure of the nested set of higher frame bundles over a differentiable manifold. Examples of covariant geometric objects include not only linear tensor fields, densities and forms, but affinity fields, sectors and sector forms, higher order frame fields, etc., often having nonlinear transformation rules and Lie derivatives. The intrinsic, or invariant, sets of forms that arise on frame bundles satisfy the graded Cartan-Maurer structure equations of an infinite Lie algebra. Reduction of these gives invariant structure equations for Lie pseudogroups, and for G-structures of various orders. Some new results are introduced for prolongation of structure equations, and for treatment of Riemannian geometry with higher-order moving frames. The use of invariant form equations for nonlinear field physics is implicitly advocated.
On covariance structure in noisy, big data
Paffenroth, Randy C.; Nong, Ryan; Du Toit, Philip C.
2013-09-01
Herein we describe theory and algorithms for detecting covariance structures in large, noisy data sets. Our work uses ideas from matrix completion and robust principal component analysis to detect the presence of low-rank covariance matrices, even when the data is noisy, distorted by large corruptions, and only partially observed. In fact, the ability to handle partial observations combined with ideas from randomized algorithms for matrix decomposition enables us to produce asymptotically fast algorithms. Herein we will provide numerical demonstrations of the methods and their convergence properties. While such methods have applicability to many problems, including mathematical finance, crime analysis, and other large-scale sensor fusion problems, our inspiration arises from applying these methods in the context of cyber network intrusion detection.
Covariant Quantization of CPT-violating Photons
Colladay, D; Noordmans, J P; Potting, R
2016-01-01
We perform the covariant canonical quantization of the CPT- and Lorentz-symmetry-violating photon sector of the minimal Standard-Model Extension, which contains a general (timelike, lightlike, or spacelike) fixed background tensor $k_{AF}^\\mu$. Well-known stability issues, arising from complex-valued energy states, are solved by introducing a small photon mass, orders of magnitude below current experimental bounds. We explicitly construct a covariant basis of polarization vectors, in which the photon field can be expanded. We proceed to derive the Feynman propagator and show that the theory is microcausal. Despite the occurrence of negative energies and vacuum-Cherenkov radiation, we do not find any runaway stability issues, because the energy remains bounded from below. An important observation is that the ordering of the roots of the dispersion relations is the same in any observer frame, which allows for a frame-independent condition that selects the correct branch of the dispersion relation. This turns ou...
Twisted Covariant Noncommutative Self-dual Gravity
Estrada-Jimenez, S; Obregón, O; Ramírez, C
2008-01-01
A twisted covariant formulation of noncommutative self-dual gravity is presented. The recent formulation introduced by J. Wess and coworkers for constructing twisted Yang-Mills fields is used. It is shown that the noncommutative torsion is solved at any order of the $\\theta$-expansion in terms of the tetrad and the extra fields of the theory. In the process the first order expansion in $\\theta$ for the Pleba\\'nski action is explicitly obtained.
Twisted covariant noncommutative self-dual gravity
International Nuclear Information System (INIS)
A twisted covariant formulation of noncommutative self-dual gravity is presented. The formulation for constructing twisted noncommutative Yang-Mills theories is used. It is shown that the noncommutative torsion is solved at any order of the θ expansion in terms of the tetrad and some extra fields of the theory. In the process the first order expansion in θ for the Plebanski action is explicitly obtained.
Area spectrum in Lorentz covariant loop gravity
Alexandrov, S.; Vassilevich, D.
2001-01-01
We use the manifestly Lorentz covariant canonical formalism to evaluate eigenvalues of the area operator acting on Wilson lines. To this end we modify the standard definition of the loop states to make it applicable to the present case of non-commutative connections. The area operator is diagonalized by using the usual shift ambiguity in definition of the connection. The eigenvalues are then expressed through quadratic Casimir operators. No dependence on the Immirzi parameter appears.
Area spectrum in Lorentz covariant loop gravity
International Nuclear Information System (INIS)
We use the manifestly Lorentz covariant canonical formalism to evaluate eigenvalues of the area operator acting on Wilson lines. To this end we modify the standard definition of the loop states to make it applicable to the present case of noncommutative connections. The area operator is diagonalized by using the usual shift ambiguity in the definition of the connection. The eigenvalues are then expressed through quadratic Casimir operators. No dependence on the Immirzi parameter appears
Risk evaluation with enhaced covariance matrix
Urbanowicz, K; Richmond, P; Holyst, Janusz A.; Richmond, Peter; Urbanowicz, Krzysztof
2006-01-01
We propose a route for the evaluation of risk based on a transformation of the covariance matrix. The approach uses a `potential' or `objective' function. This allows us to rescale data from diferent assets (or sources) such that each set then has similar statistical properties in terms of their probability distributions. The method is tested using historical data from both the New York and Warsaw Stock Exchanges.
Torsion and geometrostasis in covariant superstrings
Energy Technology Data Exchange (ETDEWEB)
Zachos, C.
1985-01-01
The covariant action for freely propagating heterotic superstrings consists of a metric and a torsion term with a special relative strength. It is shown that the strength for which torsion flattens the underlying 10-dimensional superspace geometry is precisely that which yields free oscillators on the light cone. This is in complete analogy with the geometrostasis of two-dimensional sigma-models with Wess-Zumino interactions. 13 refs.
Covariates of Craving in Actively Drinking Alcoholics
Chakravorty, Subhajit; Samuel T Kuna; Zaharakis, Nikola; O’Brien, Charles P.; Kampman, Kyle M.; Oslin, David
2010-01-01
The goal of this cross-sectional study was to assess the relationship of alcohol craving with biopsychosocial and addiction factors that are clinically pertinent to alcoholism treatment. Alcohol craving was assessed in 315 treatment-seeking, alcohol dependent subjects using the PACS questionnaire. Standard validated questionnaires were used to evaluate a variety of biological, addiction, psychological, psychiatric, and social factors. Individual covariates of craving included age, race, probl...
Covariant method for calculating helicity amplitudes
International Nuclear Information System (INIS)
We present an alternative approach for calculating helicity amplitudes for processes involving both massless and massive fermions. With this method one can easily obtain covariant expressions for the helicity amplitudes. The final expressions involve only four-vector products and are independent of the basis for γ matrices or specific form of the spinors. We use the method to obtain the helicity amplitudes for several processes involving top quark production. copyright 1996 The American Physical Society
Economical phase-covariant cloning with multiclones
Institute of Scientific and Technical Information of China (English)
Zhang Wen-Hai; Ye Liu
2009-01-01
This paper presents a very simple method to derive the explicit transformations of the optimal economical to M phase-covariant cloning. The fidelity of clones reaches the theoretic bound [D'Ariano G M and Macchiavello C 2003 Phys. Rcv. A 67 042306]. The derived transformations cover the previous contributions [Delgado Y,Lamata L et al,2007 Phys. Rev. Lett. 98 150502] in which M must be odd.
High-dimensional covariance estimation with high-dimensional data
Pourahmadi, Mohsen
2013-01-01
Methods for estimating sparse and large covariance matrices Covariance and correlation matrices play fundamental roles in every aspect of the analysis of multivariate data collected from a variety of fields including business and economics, health care, engineering, and environmental and physical sciences. High-Dimensional Covariance Estimation provides accessible and comprehensive coverage of the classical and modern approaches for estimating covariance matrices as well as their applications to the rapidly developing areas lying at the intersection of statistics and mac
The Beta-MANOVA Ensemble with General Covariance
Dubbs, Alexander; Edelman, Alan
2013-01-01
We find the joint generalized singular value distribution and largest generalized singular value distributions of the $\\beta$-MANOVA ensemble with positive diagonal covariance, which is general. This has been done for the continuous $\\beta > 0$ case for identity covariance (in eigenvalue form), and by setting the covariance to $I$ in our model we get another version. For the diagonal covariance case, it has only been done for $\\beta = 1,2,4$ cases (real, complex, and quaternion matrix entries...
Sparse covariance thresholding for high-dimensional variable selection
Daye, X. Jessie Jeng And Z. John
2010-01-01
In high-dimensions, many variable selection methods, such as the lasso, are often limited by excessive variability and rank deficiency of the sample covariance matrix. Covariance sparsity is a natural phenomenon in high-dimensional applications, such as microarray analysis, image processing, etc., in which a large number of predictors are independent or weakly correlated. In this paper, we propose the covariance-thresholded lasso, a new class of regression methods that can utilize covariance ...
Analytical Solution of Covariance Evolution for Regular LDPC Codes
Nozaki, Takayuki; Kasai, Kenta; Sakaniwa, Kohichi
2009-01-01
The covariance evolution is a system of differential equations with respect to the covariance of the number of edges connecting to the nodes of each residual degree. Solving the covariance evolution, we can derive distributions of the number of check nodes of residual degree 1, which helps us to estimate the block error probability for finite-length LDPC code. Amraoui et al.\\ resorted to numerical computations to solve the covariance evolution. In this paper, we give the analytical solution o...
How covariant is the galaxy luminosity function?
Smith, Robert E
2012-01-01
We investigate the error properties of certain galaxy luminosity function (GLF) estimators. Using a cluster expansion of the density field, we show how, for both volume and flux limited samples, the GLF estimates are covariant. The covariance matrix can be decomposed into three pieces: a diagonal term arising from Poisson noise; a sample variance term arising from large-scale structure in the survey volume; an occupancy covariance term arising due to galaxies of different luminosities inhabiting the same cluster. To evaluate the theory one needs: the mass function and bias of clusters, and the conditional luminosity function (CLF). We use a semi-analytic model (SAM) galaxy catalogue from the Millennium run N-body simulation and the CLF of Yang et al. (2003) to explore these effects. The GLF estimates from the SAM and the CLF qualitatively reproduce results from the 2dFGRS. We also measure the luminosity dependence of clustering in the SAM and find reasonable agreement with 2dFGRS results for bright galaxies. ...
Covariance tracking: architecture optimizations for embedded systems
Romero, Andrés; Lacassagne, Lionel; Gouiffès, Michèle; Zahraee, Ali Hassan
2014-12-01
Covariance matching techniques have recently grown in interest due to their good performances for object retrieval, detection, and tracking. By mixing color and texture information in a compact representation, it can be applied to various kinds of objects (textured or not, rigid or not). Unfortunately, the original version requires heavy computations and is difficult to execute in real time on embedded systems. This article presents a review on different versions of the algorithm and its various applications; our aim is to describe the most crucial challenges and particularities that appeared when implementing and optimizing the covariance matching algorithm on a variety of desktop processors and on low-power processors suitable for embedded systems. An application of texture classification is used to compare different versions of the region descriptor. Then a comprehensive study is made to reach a higher level of performance on multi-core CPU architectures by comparing different ways to structure the information, using single instruction, multiple data (SIMD) instructions and advanced loop transformations. The execution time is reduced significantly on two dual-core CPU architectures for embedded computing: ARM Cortex-A9 and Cortex-A15 and Intel Penryn-M U9300 and Haswell-M 4650U. According to our experiments on covariance tracking, it is possible to reach a speedup greater than ×2 on both ARM and Intel architectures, when compared to the original algorithm, leading to real-time execution.
Using Covariance Analysis to Assess Pointing Performance
Bayard, David; Kang, Bryan
2009-01-01
A Pointing Covariance Analysis Tool (PCAT) has been developed for evaluating the expected performance of the pointing control system for NASA s Space Interferometry Mission (SIM). The SIM pointing control system is very complex, consisting of multiple feedback and feedforward loops, and operating with multiple latencies and data rates. The SIM pointing problem is particularly challenging due to the effects of thermomechanical drifts in concert with the long camera exposures needed to image dim stars. Other pointing error sources include sensor noises, mechanical vibrations, and errors in the feedforward signals. PCAT models the effects of finite camera exposures and all other error sources using linear system elements. This allows the pointing analysis to be performed using linear covariance analysis. PCAT propagates the error covariance using a Lyapunov equation associated with time-varying discrete and continuous-time system matrices. Unlike Monte Carlo analysis, which could involve thousands of computational runs for a single assessment, the PCAT analysis performs the same assessment in a single run. This capability facilitates the analysis of parametric studies, design trades, and "what-if" scenarios for quickly evaluating and optimizing the control system architecture and design.
The Genus Austroleptis from South Chile and Patagonia (Diptera, Rhagionidae)
NAGATOMI, Akira; NAGATOMI, Hisako; ナガトミ, アキラ; ナガトミ, ヒサコ; 永冨, 昭; 永冨, 尚子
1988-01-01
The genus Austroleptis from South Chile and Patagonia is revised and three new species are added. So, there are eight known species, five of which are from South Chile and Patagonia and three from Australia and Tasmania.
Helicobacter pylori infection in Chile.
Figueroa, G; Acuña, R; Troncoso, M; Portell, D P; Toledo, M S; Valenzuela, J
1997-11-01
This article summarizes studies designed to evaluate the role of Helicobacter pylori infection in Chile, described in 21 reports from nine centers in various Chilean regions published between 1985 and 1995. According to their data, H. pylori infection is quite frequent among patients with a variety of gastric conditions, including adults (43%-92%) and children (6%-100%). Levels of specific IgG antibodies to H. pylori are also elevated among patients with duodenal ulcers (100%) and gastritis (86%) as well as asymptomatic adults (75%). Combination therapy with three (but not two) drugs has been proved effective, with clinical improvement, ulcer cure, and H. pylori eradication occurring in well-controlled studies. Available evidence suggests that antibiotic resistance is not a major problem in treatment. The H. pylori reinfection rate is low (4.2% per year), suggesting that combination therapy with three drugs constitutes a cost-effective alternative for treating colonized symptomatic patients. Concurrent preliminary studies revealed that antibodies to VacA but not CagA proteins correlate with disease severity in Chilean patients. It can be concluded that local research assists local administrators of health resources to implement adequate policies to prevent, control, and treat H. pylori-related pathologies.
Regulated electricity retailing in Chile
Energy Technology Data Exchange (ETDEWEB)
Galetovic, Alexander, E-mail: alexander@galetovic.cl [Facultad de Ciencias Economicas y Empresariales, Universidad de los Andes, Santiago, Chile. Av. San Carlos de Apoquindo 2200, Las Condes, Santiago (Chile); Munoz, Cristian M., E-mail: cmunozm@aes.com [AES Gener and Departamento de Ingenieria Electrica, Universidad Catolica de Chile (Chile)
2011-10-15
While some countries have unbundled distribution and retailing, skeptics argue that the physical attributes of electricity make retailers redundant. Instead, it is claimed that passive pass through of wholesale prices plus regulated charges for transmission and distribution suffice for customers to benefit from competitive generation markets. We review the Chilean experience with regulated retailing and pass through of wholesale prices. We argue that when energy wholesale prices are volatile and prices are stabilized, distortions emerge. Regulated retailers gain little by mitigating or correcting them. On the contrary, sometimes price distortions increase their profits. We estimate the cost of three distortions that neither regulated retailers nor the regulator have shown any interest in correcting. - Highlights: > We review Chile's experience with regulated electricity retailing. > Distortions emerge when energy wholesale prices are volatile and prices stabilized. > Regulated retailers gain little by mitigating or correcting distortions. > Sometimes price distortions increase retailers' profits. > We estimate the cost of three distortions, which retailers have not corrected.
Regulated electricity retailing in Chile
International Nuclear Information System (INIS)
While some countries have unbundled distribution and retailing, skeptics argue that the physical attributes of electricity make retailers redundant. Instead, it is claimed that passive pass through of wholesale prices plus regulated charges for transmission and distribution suffice for customers to benefit from competitive generation markets. We review the Chilean experience with regulated retailing and pass through of wholesale prices. We argue that when energy wholesale prices are volatile and prices are stabilized, distortions emerge. Regulated retailers gain little by mitigating or correcting them. On the contrary, sometimes price distortions increase their profits. We estimate the cost of three distortions that neither regulated retailers nor the regulator have shown any interest in correcting. - Highlights: → We review Chile's experience with regulated electricity retailing. → Distortions emerge when energy wholesale prices are volatile and prices stabilized. → Regulated retailers gain little by mitigating or correcting distortions. → Sometimes price distortions increase retailers' profits. → We estimate the cost of three distortions, which retailers have not corrected.
On the covariance matrices in the evaluated nuclear data
International Nuclear Information System (INIS)
The implications of the uncertainties of nuclear data on reactor calculations are shown. The concept of variance, covariance and correlation are expressed first by intuitive definitions and then through statistical theory. The format of the covariance data for ENDF/B is explained and the formulas to obtain the multigroup covariances are given. (Author)
Earth Observation System Flight Dynamics System Covariance Realism
Zaidi, Waqar H.; Tracewell, David
2016-01-01
This presentation applies a covariance realism technique to the National Aeronautics and Space Administration (NASA) Earth Observation System (EOS) Aqua and Aura spacecraft based on inferential statistics. The technique consists of three parts: collection calculation of definitive state estimates through orbit determination, calculation of covariance realism test statistics at each covariance propagation point, and proper assessment of those test statistics.
Conformally covariant operators and effective action in external gravitational field
International Nuclear Information System (INIS)
The n-dimensional expressions for the second order conformally covariant differentional operators acting on vector and tensor fields and for the fourth order conformally covariant operator acting on scalar fields are obtained. For the fourth order operator one-loop effective action is evaluated in four dimensions. The possibility of effective action evaluation for other conformally covariant operators is discussed
[Beginning of the Microbiology education in Chile: formation centers].
Osorio, Carlos
2015-08-01
The first Chair of Microbiology in Chile was created in the School of Medicine of the Cañadilla at the University of Chile in 1892. Dr. Alejandro del Río Soto Aguilar was its first Professor. For almost three decades it was the only educational center for microbiologists in Chile. Among them were the first Professors of the new School of Medicine of the Catholic University of Chile and of the University of Concepción.
Taxonomic reasoning: The case of giant wrinkled frog
Dinesh, KP; Radhakrishna, C; Reddy, Manjunatha AH; Gururaja, KV
2008-01-01
A recent issue of Current Science carried a correspondence entitled ‘Taxonomic vandalism: The case of the giant wrinkled frog’ by Ranjit Daniels1. The author is critical of a communication authored by us.
taxonomic diversity and pest vulnerability in street tree assemblages
U.S. Environmental Protection Agency — Urban foresters routinely emphasise the importance of taxonomic diversity to reduce the vulnerability of tree assemblages to invasive pests, but it is unclear to...
Los patelogastrópodos intermareales de Chile y Perú Intertidal limpets of Chile and Peru
Directory of Open Access Journals (Sweden)
CARMEN ESPOZ
2004-06-01
diversos del mundo. Más aún, esta variabilidad y flexibilidad pueden ser responsables de las confusiones taxonómicas que han rodeado a este conjunto faunísticoIn this study we present a classification system reflecting the phylogenetic relationships for the intertidal patellogastropods of Chile and Peru. We infer phylogenetic relationships between limpets species using DNA sequences from the 16S region of the mitochondrial genome. We include a comparative limpet study of: shell structure, color and morphological patterns of the shell, radular teeth and anatomy. Additionally, we provide information about the distribution and ecology for members of this group within the studied area. The results show a Chilean-Peruvian Lottiidae fauna consisting of at least nine species, which are grouped into a single monophyletic clade Scurria (S. variabilis, S. zebrina, S. viridula, S. plana, S. scurra, S. araucana, S. ceciliana and a non identificated species, and a "problematic taxon" preliminarily assigned to the genus Lottia (Lottia orbignyi. The group of species is present in the intertidal rocky shores between 5º S and 54º S, from the upper to the lower intertidal fringes, ranging from exposed to protected areas. The systematic outcome of this study suggests the synonymization of S. parasitica to S. variabilis, and of S. ceciliana to S. boehmita. According to our field results, the species S. variabilis shows at least three ecophenotypes: (1 on rocky substrates along the full geographic range, (2 on the shells of the key-hole limpets: Fissurella crassa and F. limbata mainly in central and south of Chile, and (3 on the chiton plates of Enoplochiton niger in the north of Chile and south of Perú. S. ceciliana is a species in which morphology and color patterns are highly variable. In general, this variability indicates that the Chilean-Peruvian limpet species are among the most complex and diverse limpet fauna in the world. This, may reflects the taxonomic confusion which has
Covariant Quantum Gravity with Continuous Quantum Geometry I: Covariant Hamiltonian Framework
Pilc, Marián
2016-01-01
The first part of the series is devoted to the formulation of the Einstein-Cartan Theory within the covariant hamiltonian framework. In the first section the general multisymplectic approach is revised and the notion of the d-jet bundles is introduced. Since the whole Standard Model Lagrangian (including gravity) can be written as the functional of the forms, the structure of the d-jet bundles is more appropriate for the covariant hamiltonian analysis than the standard jet bundle approach. The definition of the local covariant Poisson bracket on the space of covariant observables is recalled. The main goal of the work is to show that the gauge group of the Einstein-Cartan theory is given by the semidirect product of the local Lorentz group and the group of spacetime diffeomorphisms. Vanishing of the integral generators of the gauge group is equivalent to equations of motion of the Einstein-Cartan theory and the local covariant algebra generated by Noether's currents is closed Lie algebra.
7 CFR 319.56-38 - Citrus from Chile.
2010-01-01
... 7 Agriculture 5 2010-01-01 2010-01-01 false Citrus from Chile. 319.56-38 Section 319.56-38... from Chile. Clementines (Citrus reticulata Blanco var. Clementine), mandarins (Citrus reticulata Blanco), and tangerines (Citrus reticulata Blanco) may be imported into the United States from Chile,...
Taxonomic diversity and distinctness indices in assessment of weed communities
Directory of Open Access Journals (Sweden)
Magdalena Jastrzębska
2012-12-01
Full Text Available This paper contains an analysis of taxonomic weed biodiversity in the cultivation of spring barley in the period of 1990-2004, grown in crop rotation after potato with a 25% share of this cereal (potato - spring barley - field pea - winter triticale as well as in crop rotation with its 75% share (potato - spring barley - spring barley - spring barley in which barley was grown once and twice after the same barley crop. No weed control was used in the present experiment. Every year in the spring (at full emergence of the cereal crop and before harvest, the species composition and the numbers of individual weed species were determined, as well as weed biomass before harvest. On this basis, the taxonomic diversity and distinctness indices were calculated. Potato/barley crop rotation with a 25% share of this cereal and growing spring barley once and twice after the same barley crop did not differentiate taxonomic weed biodiversity. However, it was positively correlated with rainfall abundance during the growing season and negatively correlated with mean temperature. The taxonomic diversity indices were positively correlated with species richness and species diversity, whereas the taxonomic distinctness indices did not generally show any relationship with these measures. Spring barley grain yield did not depend on taxonomic biodiversity of weed communities.
Quantum energy inequalities and local covariance II: categorical formulation
Fewster, Christopher J.
2007-11-01
We formulate quantum energy inequalities (QEIs) in the framework of locally covariant quantum field theory developed by Brunetti, Fredenhagen and Verch, which is based on notions taken from category theory. This leads to a new viewpoint on the QEIs, and also to the identification of a new structural property of locally covariant quantum field theory, which we call local physical equivalence. Covariant formulations of the numerical range and spectrum of locally covariant fields are given and investigated, and a new algebra of fields is identified, in which fields are treated independently of their realisation on particular spacetimes and manifestly covariant versions of the functional calculus may be formulated.
Expedition Atacama - project AMOS in Chile
Tóth, J.; Kaniansky, S.
2016-01-01
The Slovak Video Meteor Network operates since 2009 (Tóth et al., 2011). It currently consists of four semi-automated all-sky video cameras, developed at the Astronomical Observatory in Modra, Comenius University in Bratislava, Slovakia. Two new generations of AMOS (All-sky Meteor Orbit System) cameras operate fully automatically at the Canary Islands, Tenerife and La Palma, since March 2015 (Tóth et al., 2015). As a logical step, we plan to cover the southern hemisphere from Chile. We present observational experiences in meteor astronomy from the Atacama Desert and other astronomical sites in Chile. This summary of the observations lists meteor spectra records (26) between Nov.5-13, 2015 mostly Taurid meteors, single and double station meteors as well as the first light from the permanent AMOS stations in Chile.
Directory of Open Access Journals (Sweden)
JARLE W BJERKE
2003-03-01
Full Text Available ABSTRACT The taxonomy and ecology of the sorediate species of Menegazzia from the southernmost regions of Chile and Argentina and the South Atlantic Islands was recently published, only with sporadic reports from the more northern regions. In the present work the distribution patterns and habitat ecology of the sorediate species are discussed, with emphasis on the area north of 48º S. Eleven species are treated. Menegazzia subpertusa, an epiphyte of sclerophyll scrubs, is recorded from South America for the first time (Chile and Argentina. Menegazzia neozelandica has a disjunct distribution in Chile, with occurrences in Fray Jorge (Fourth Region of Chile and on Islas Juan Fernández, and along the coast south of latitude 38º S. Menegazzia kawesqarica and M. tenuis are most common in the southernmost part of Chile, but are also found at high altitudes at lower latitudes. Additional treated species are M. chrysogaster, M. fumarprotocetrarica, M. globulifera, M. magellanica, M. norsorediata, M. sanguinascens and M. wandae. Several of the sorediate species are early colonisers of newly developed substrates. They show variable occurrences along light and humidity gradients. Distribution maps and a revised key are presented.Recientemente se han publicado datos sobre la taxonomía y ecología de las especies sorediosas de Menegazzia representadas en las regiones más australes de Chile y Argentina e islas del Atlántico Sur, además de registros esporádicos en zonas ubicadas más al norte en Chile. En este trabajo se discuten los patrones de distribución y la ecología del hábitat de 11 especies sorediosas, con especial enfásis en aquellas que se desarrollan al norte de los 48º S. Menegazzia subpertusa, un epífito de arbustos esclerófilos, se registra por primera vez en América (Chile y Argentina. Menegazzia neozelandica tiene una distribución discontinua en Chile; ha sido recolectada en Fray Jorge (Cuarta Región de Chile, Islas Juan Fern
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FABIAN M JAKSIC
2010-01-01
Full Text Available A partir de la revisión de la sección zoológica de la Historia Física y Política de Chile elaborada por Claude Gay, analizamos su contribución al conocimiento de los vertebrados chilenos. Esta sección incluyó la descripción de 483 especies distribuidas en 68 mamíferos, 259 aves, 31 reptiles, 16 anfibios y 109 peces; de ellas, 50 especies fueron descritas por primera vez para la ciencia, pero los análisis taxonómicos posteriores sinonimizaron cerca del 58 % de ellas, quedando como válidas solo 21 especies. Este valor implica que el 1.1 % de la fauna de vertebrados de Chile actualmente conocida (unas 1900 especies fue descrita por primera vez en dicha obra monumental.By reviewing the zoological section of the Historia Física y Política de Chile written by Claude Gay, we analyze his contributions to the understanding of the Chilean vertebrates, which included 483 species: 68 mammals, 259 birds, 31 reptiles, 16 amphibians, and 109 fishes. Gay documented 50 species as new taxa to science, but subsequent taxonomic analyses sinonimized 58 % of those species; thus currently only 21 species are recognized as valid. This means that 1.1 % of the Chilean vertebrates currently recognized were described in this monumental publication.
Income Inequality in Chile: 1990-2006
Alain Hourton
2012-01-01
The entrance of Chile to the Organization for the Economic Cooperation and Development, as the first South American country and second after Mexico in Latin America, sets a landmark in the development path that since the beginning of the 1990s decade has seemed to lead this country to a privileged position in the region. Given the reforms taken by the military regime in the 1980s, Chile is one of the most market-oriented countries in Latin America, with Free Trade Agreements and Economical Pa...
Entrevista : Carlos Honorato Comandari (ProChile)
Comandari, Carlos Honorato
2013-01-01
Ingeniero Comercial de la Universidad Finis Terrae y MBA de Babson College (Estados Unidos). En 2010, asumió como Subdirector Internacional de ProChile, desde donde lideró la creación del programa de apoyo a la internacionalización de la innovación chilena, CONTACTChile. Fue nombrado Director de ProChile en mayo de 2013, con la responsabilidad de conducir las más de 50 oficinas comerciales de la institución en el mundo y las 15 oficinas regionales dentro del país. En este período ha intensifi...
MATXTST, Basic Operations for Covariance Matrices
International Nuclear Information System (INIS)
1 - Description of program or function: MATXTST and MATXTST1 perform the following operations for a covariance matrix: - test for singularity; - test for positive definiteness; - compute the inverse if the matrix is non-singular; - compute the determinant; - determine the number of positive, negative, and zero eigenvalues; - examine all possible 3 X 3 cross correlations within a sub-matrix corresponding to a leading principal minor which is non-positive definite. While the two programs utilize the same input, the calculational procedures employed are somewhat different and their functions are complementary. The available input options include: i) the full covariance matrix, ii) the basic variables plus the relative covariance matrix, or iii) uncertainties in the basic variables plus the correlation matrix. 2 - Method of solution: MATXTST employs LINPACK subroutines SPOFA and SPODI to test for positive definiteness and to perform further optional calculations. Subroutine SPOFA factors a symmetric matrix M using the Cholesky algorithm to determine the elements of a matrix R which satisfies the relation M=R'R, where R' is the transposed matrix of R. Each leading principal minor of M is tested until the first one is found which is not positive definite. MATXTST1 uses LINPACK subroutines SSICO, SSIFA, and SSIDI to estimate whether the matrix is near to singularity or not (SSICO), and to perform the matrix diagonalization process (SSIFA). The algorithm used in SSIFA is generalization of the Method of Lagrange Reduction. SSIDI is used to compute the determinant and inertia of the matrix. 3 - Restrictions on the complexity of the problem: Matrices of sizes up to 50 X 50 elements can be treated by present versions of the programs
Spatiotemporal noise covariance estimation from limited empirical magnetoencephalographic data
Energy Technology Data Exchange (ETDEWEB)
Jun, Sung C [MS-D454, Applied Modern Physics Group, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Plis, Sergey M [MS-D454, Applied Modern Physics Group, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Ranken, Doug M [MS-D454, Applied Modern Physics Group, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Schmidt, David M [MS-D454, Applied Modern Physics Group, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2006-11-07
The performance of parametric magnetoencephalography (MEG) and electroencephalography (EEG) source localization approaches can be degraded by the use of poor background noise covariance estimates. In general, estimation of the noise covariance for spatiotemporal analysis is difficult mainly due to the limited noise information available. Furthermore, its estimation requires a large amount of storage and a one-time but very large (and sometimes intractable) calculation or its inverse. To overcome these difficulties, noise covariance models consisting of one pair or a sum of multi-pairs of Kronecker products of spatial covariance and temporal covariance have been proposed. However, these approaches cannot be applied when the noise information is very limited, i.e., the amount of noise information is less than the degrees of freedom of the noise covariance models. A common example of this is when only averaged noise data are available for a limited prestimulus region (typically at most a few hundred milliseconds duration). For such cases, a diagonal spatiotemporal noise covariance model consisting of sensor variances with no spatial or temporal correlation has been the common choice for spatiotemporal analysis. In this work, we propose a different noise covariance model which consists of diagonal spatial noise covariance and Toeplitz temporal noise covariance. It can easily be estimated from limited noise information, and no time-consuming optimization and data-processing are required. Thus, it can be used as an alternative choice when one-pair or multi-pair noise covariance models cannot be estimated due to lack of noise information. To verify its capability we used Bayesian inference dipole analysis and a number of simulated and empirical datasets. We compared this covariance model with other existing covariance models such as conventional diagonal covariance, one-pair and multi-pair noise covariance models, when noise information is sufficient to estimate them. We
SO(2,1) Covariant IIB Superalgebra
Abe, Mitsuko; Hatsuda, Machiko; Kamimura, Kiyoshi; Tokunaga, Takashi
1999-01-01
We propose a type IIB super-Poincare algebra with SO(2,1) covariant central extension. Together with SO(2,1) and SO(9,1) generators, a SO(2,1) triplet (momenta), a Majorana-spinor doublet (supercharges) and a Rarita-Schwinger central charge generate a group, G. We consider a coset G/H where H=(SO(2) x Lorentz), and the SL(2,R) 2-form doublet is obtained by the coset construction. It is shown that U(1) connections, whose strengths are associated with 2-forms, are recognized as coordinates of t...
Radiative Transfer in Special Relativity: Covariance
Duque, Mauricio; Duque, Carlos
2007-01-01
The purpose is to introduce in a clear and direct way the students of undergraduate courses in physics and/or astronomy to the subject of radiative transfer. A pedagogical revision is made in order to obtain the radiative transfer equation, its restrictions and the different types of interactions present between the radiation and the matter. Because in the classical literature about radiative transfer the covariance is not fully developed, we show in an explicit manner detail calculations and then we discuss the relativistic effects.
Minimal covariant observables identifying all pure states
Energy Technology Data Exchange (ETDEWEB)
Carmeli, Claudio, E-mail: claudio.carmeli@gmail.com [D.I.M.E., Università di Genova, Via Cadorna 2, I-17100 Savona (Italy); I.N.F.N., Sezione di Genova, Via Dodecaneso 33, I-16146 Genova (Italy); Heinosaari, Teiko, E-mail: teiko.heinosaari@utu.fi [Turku Centre for Quantum Physics, Department of Physics and Astronomy, University of Turku (Finland); Toigo, Alessandro, E-mail: alessandro.toigo@polimi.it [Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); I.N.F.N., Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy)
2013-09-02
It has been recently shown by Heinosaari, Mazzarella and Wolf (2013) [1] that an observable that identifies all pure states of a d-dimensional quantum system has minimally 4d−4 outcomes or slightly less (the exact number depending on d). However, no simple construction of this type of minimal observable is known. We investigate covariant observables that identify all pure states and have minimal number of outcomes. It is shown that the existence of this kind of observables depends on the dimension of the Hilbert space.
Linear Covariance Analysis and Epoch State Estimators
Markley, F. Landis; Carpenter, J. Russell
2014-01-01
This paper extends in two directions the results of prior work on generalized linear covariance analysis of both batch least-squares and sequential estimators. The first is an improved treatment of process noise in the batch, or epoch state, estimator with an epoch time that may be later than some or all of the measurements in the batch. The second is to account for process noise in specifying the gains in the epoch state estimator. We establish the conditions under which the latter estimator is equivalent to the Kalman filter.
Non-evaluation applications for covariance matrices
Energy Technology Data Exchange (ETDEWEB)
Smith, D.L.
1982-05-01
The possibility for application of covariance matrix techniques to a variety of common research problems other than formal data evaluation are demonstrated by means of several examples. These examples deal with such matters as fitting spectral data, deriving uncertainty estimates for results calculated from experimental data, obtaining the best values for plurally-measured quantities, and methods for analysis of cross section errors based on properties of the experiment. The examples deal with realistic situations encountered in the laboratory, and they are treated in sufficient detail to enable a careful reader to extrapolate the methods to related problems.
Directory of Open Access Journals (Sweden)
J. LÓPEZ
1999-01-01
Full Text Available Se describe el primer caso de Ehrlichiosis canina detectado en Chile, causado por la rickettsia Ehrlichia canis y transmitida por el vector Rhipicephalus sanguineus. El diagnóstico clínico fue confirmado en Alemania por Inmunofluorescencia Indirecta (IFATThe first case of canine ehrlichiosis detected in Chile is described. It is caused by the rickettsia Ehrlichia canis and carried by the vektor Rhipicephalus sanguineus. The clinical diagnosis was confirmed in Germany using the Immunofluorescent Antibody Test (IFA
Covariant Entropy Bound and Padmanabhan's Emergent Paradigm
Hadi, H; Darabi, F
2016-01-01
The covariant entropy conjecture is invariant under time reversal and consequently its origin must be statistical rather than thermodynamical. This may impose a fundamental constraint on the number of degrees of freedom in nature. Indeed, the covariant entropy bound imposes an upper entropy bound for any physical system. Considering a cosmological system, we show that Padmanabhan's emergent paradigm, which indicates that the emergence of cosmic space is due to the discrepancy between the surface and bulk degrees of freedom, leads to a lower entropy bound. The lower and upper entropy bounds may coincide on the apparent horizon for the radiation field and dark energy with the equations of state $\\omega=\\frac{1}{3}$ and $\\omega=-1$, respectively. Moreover, the maximal entropy inside the apparent horizon occurs when it is filled completely by the radiation field or dark energy. It turns out that for dark energy case (pure de Sitter space)\\ the holographic principle is satisfied in the sense that the number of deg...
Power Spectrum Super-Sample Covariance
Takada, Masahiro
2013-01-01
We provide a simple, unified approach to describing the impact of super-sample covariance on power spectrum estimation in a finite-volume survey. For a wide range of survey volumes, the sample variance that arises from modes that are larger than the survey dominates the covariance of power spectrum estimators for modes much smaller than the survey. The perturbative and deeply nonlinear versions of this effect are known as beat coupling and halo sample variance respectively. We show that they are unified by the matter trispectrum of squeezed configurations and that such configurations obey a consistency relation which relates them to the response of the power spectrum to a change in the background density. Our method also applies to statistics that are based on radial projections of the density field such as weak lensing shear. While we use the halo model for an analytic description to expose the nature of the effect, the consistency description enables an accurate calibration of the full effect directly from ...
Shrinkage covariance matrix approach for microarray data
Karjanto, Suryaefiza; Aripin, Rasimah
2013-04-01
Microarray technology was developed for the purpose of monitoring the expression levels of thousands of genes. A microarray data set typically consists of tens of thousands of genes (variables) from just dozens of samples due to various constraints including the high cost of producing microarray chips. As a result, the widely used standard covariance estimator is not appropriate for this purpose. One such technique is the Hotelling's T2 statistic which is a multivariate test statistic for comparing means between two groups. It requires that the number of observations (n) exceeds the number of genes (p) in the set but in microarray studies it is common that n Hotelling's T2 statistic with the shrinkage approach is proposed to estimate the covariance matrix for testing differential gene expression. The performance of this approach is then compared with other commonly used multivariate tests using a widely analysed diabetes data set as illustrations. The results across the methods are consistent, implying that this approach provides an alternative to existing techniques.
Piecewise linear regression splines with hyperbolic covariates
International Nuclear Information System (INIS)
Consider the problem of fitting a curve to data that exhibit a multiphase linear response with smooth transitions between phases. We propose substituting hyperbolas as covariates in piecewise linear regression splines to obtain curves that are smoothly joined. The method provides an intuitive and easy way to extend the two-phase linear hyperbolic response model of Griffiths and Miller and Watts and Bacon to accommodate more than two linear segments. The resulting regression spline with hyperbolic covariates may be fit by nonlinear regression methods to estimate the degree of curvature between adjoining linear segments. The added complexity of fitting nonlinear, as opposed to linear, regression models is not great. The extra effort is particularly worthwhile when investigators are unwilling to assume that the slope of the response changes abruptly at the join points. We can also estimate the join points (the values of the abscissas where the linear segments would intersect if extrapolated) if their number and approximate locations may be presumed known. An example using data on changing age at menarche in a cohort of Japanese women illustrates the use of the method for exploratory data analysis. (author)
Target Detection Using Nonsingular Approximations for a Singular Covariance Matrix
Directory of Open Access Journals (Sweden)
Nir Gorelik
2012-01-01
Full Text Available Accurate covariance matrix estimation for high-dimensional data can be a difficult problem. A good approximation of the covariance matrix needs in most cases a prohibitively large number of pixels, that is, pixels from a stationary section of the image whose number is greater than several times the number of bands. Estimating the covariance matrix with a number of pixels that is on the order of the number of bands or less will cause not only a bad estimation of the covariance matrix but also a singular covariance matrix which cannot be inverted. In this paper we will investigate two methods to give a sufficient approximation for the covariance matrix while only using a small number of neighboring pixels. The first is the quasilocal covariance matrix (QLRX that uses the variance of the global covariance instead of the variances that are too small and cause a singular covariance. The second method is sparse matrix transform (SMT that performs a set of K-givens rotations to estimate the covariance matrix. We will compare results from target acquisition that are based on both of these methods. An improvement for the SMT algorithm is suggested.
A Class of Population Covariance Matrices in the Bootstrap Approach to Covariance Structure Analysis
Yuan, Ke-Hai; Hayashi, Kentaro; Yanagihara, Hirokazu
2007-01-01
Model evaluation in covariance structure analysis is critical before the results can be trusted. Due to finite sample sizes and unknown distributions of real data, existing conclusions regarding a particular statistic may not be applicable in practice. The bootstrap procedure automatically takes care of the unknown distribution and, for a given…
Nuclear public information activities in Chile
International Nuclear Information System (INIS)
Nuclear plans and developing programs in developing and developed countries are facing-in a higher or lower degree- opposition from public opinion. The objectives and contents of the public education program on nuclear energy in Chile are dealt with in this paper
DEZVOLTAREA CONTEMPORANĂ A TURISMULUI DIN CHILE
Directory of Open Access Journals (Sweden)
Maria-Mihaela Győri
2011-01-01
Full Text Available The contemporary development of the Chilean Tourism sector is analyzed mainly on thebasis of data supplied by the National Service of Tourism in Chile. Figures on inboundtourism, domestic tourism, lodging, employment, receipts, as well as the existing structurewithin the sector, were taken into consideration for the investigated period of 1999-2006.
Museos de Santiago de Chile. Directorio
Carrillo, Andrea; Funes, Catherine; Heredia, Constanza; Herrera, Daniela; Suárez, Víctor
2012-01-01
Directory of the museums in Santiago of Chile categorized by subject, such as Art, Archaeology, Historic house, Science and technology, Natural science and Natural history, Specialized, Ethnography and Anthropology, History, Site museum and Other. It comprehends basic information about name, creation date, collections, services, contact info, social network accounts, website and entrance fee of the museums.
A Decade of Environment Management in Chile
Ruthenberg, Ina-Marlene
2001-01-01
This publication presents an evaluation of the Environmental Institutions Development Project in Chile, selected by Bank management to be part of an intensive learning process in final project evaluation, given its contributing factor to the Bank's knowledge base on environmental institutional development projects. The first part of the publication focuses on the project as catalyst for cu...
Sistema de salud de Chile The health system of Chile
Directory of Open Access Journals (Sweden)
Víctor Becerril-Montekio
2011-01-01
Full Text Available En este trabajo se describe el sistema de salud de Chile, incluyendo su estructura, financiamiento, beneficiarios y recursos físicos, materiales y humanos de los que dispone. Este sistema está compuesto por dos sectores, público y privado. El sector público está formado por todos los organismos que constituyen el Sistema Nacional de Servicios de Salud y cubre aproximadamente a 70% de la población, incluyendo a los pobres del campo y las ciudades, la clase media baja y los jubilados, así como los profesionales y técnicos. El sector privado cubre aproximadamente a 17.5% de la población perteneciente a los grupos sociales de mayores ingresos. Un pequeño sector de la población, perteneciente a la clase alta, realiza pagos directos de bolsillo a proveedores privados de servicios de atención a la salud. Alrededor de 10% de la población está cubierta por otras agencias públicas, fundamentalmente los Servicios de Salud de las Fuerzas Armadas. Recientemente el sistema se reformó creando el Régimen General de Garantías en Salud, que establece un Sistema Universal con Garantías Explícitas que se tradujo, en 2005, en el Plan de Acceso Universal con Garantías Explícitas (AUGE, que garantiza el acceso oportuno a servicios de calidad para 56 problemas de salud, incluyendo cáncer en niños, cáncer de mama, trastornos isquémicos del corazón, VIH/SIDA y diabetes.This paper describes the Chilean health system, including its structure, financing, beneficiaries, and its physical, material and human resources. This system has two sectors, public and private. The public sector comprises all the organisms that constitute the National System of Health Services, which covers 70% of the population, including the rural and urban poor, the low middle-class, the retired, and the self-employed professionals and technicians.The private sector covers 17.5% of the population, mostly the upper middle-class and the high-income population. A small
Directory of Open Access Journals (Sweden)
ALEJANDRA GONZÁLEZ
2004-06-01
Full Text Available In late 2001 and early 2002, a dichotomous species of Codium appeared colonizing the low intertidal and shallow subtidal bottoms of Caldera Bay, northern Chile (27° 03’ S, 70° 51’ W. Due to the ecological and economic impact the species is having in Caldera Bay and its potential spread along the Chilean coastline, we studied the taxonomic identity of the species and examined its relationships with other dichotomous species of Codium reported for temperate Pacific South America. Morphological analyses suggest that the seaweeds from Caldera Bay belong to Codium fragile (Suringar Hariot. Not only is there strong agreement in internal and external morphological characters, but among all the species reported for Peru and Chile, this is the only one exhibiting utricles with rounded, apiculate tip terminating in a mucron. This species has a broad geographic distribution in temperate waters. In Chile it was known only from the coasts of Valdivia to the Straits of Magellan (39° 48’ S, 73° 26’ W to 53° 10’ S, 73° 49’ W. This is the first record of C. fragile in northern Chile, and this study discusses several alternative hypotheses for the presence of the species into this area. The morphological characteristics of the material collected in Caldera partially agree with diagnostic characters known for C. fragile subspecies tasmanicum and C. fragile subspecies tomentosoides. However, the rapid population spread of the species in northern Chile, and recent molecular analysis support the identification of this form as the invasive C. fragile subspecies tomentosoidesA fines de 2001 y principio de 2002, apareció en el norte de Chile una especie del género Codium, de morfología dicotómica, colonizando los niveles intermareales y submareales de la Bahía de Caldera (27° 03’ S, 70° 51’ O. Debido al impacto ecológico y económico que ha provocado esta especie en la Bahía de Caldera y a su dispersión potencial a lo largo de la costa de
Flux Partitioning by Isotopic Eddy Covariance
Wehr, R.; Munger, J. W.; Nelson, D. D.; McManus, J. B.; Zahniser, M. S.; Wofsy, S. C.; Saleska, S. R.
2011-12-01
Net ecosystem-atmosphere exchange of CO2 is routinely measured by eddy covariance at sites around the world, but studies of ecosystem processes are more interested in the gross photosynthetic and respiratory fluxes that comprise the net flux. The standard method of partitioning the net flux into these components has been to extrapolate nighttime respiration into daytime based on a relationship between nighttime respiration, temperature, and sometimes moisture. However, such relationships generally account for only a small portion of the variation in nighttime respiration, and the assumption that they can predict respiration throughout the day is dubious. A promising alternate method, known as isotopic flux partitioning, works by identifying the stable isotopic signatures of photosynthesis and respiration in the CO2 flux. We have used this method to partition the net flux at Harvard Forest, MA, based on eddy covariance measurements of the net 12CO2 and 13CO2 fluxes (as well as measurements of the sensible and latent heat fluxes and other meteorological variables). The CO2 isotopologues were measured at 4 Hz by an Aerodyne quantum cascade laser spectrometer with a δ13C precision of 0.4 % in 0.25 sec and 0.02 % in 100 sec. In the absence of such high-frequency, high-precision isotopic measurements, past attempts at isotopic flux partitioning have combined isotopic flask measurements with high-frequency (total) CO2 measurements to estimate the isoflux (the EC/flask approach). Others have used a conditional flask sampling approach called hyperbolic relaxed eddy accumulation (HREA). We 'sampled' our data according to each of these approaches, for comparison, and found disagreement in the calculated fluxes of ~10% for the EC/flask approach, and ~30% for HREA, at midday. To our knowledge, this is the first example of flux partitioning by isotopic eddy covariance. Wider use of this method, enabled by a new generation of laser spectrometers, promises to open a new window
Covariate-adjusted measures of discrimination for survival data
DEFF Research Database (Denmark)
White, Ian R; Rapsomaniki, Eleni; Frikke-Schmidt, Ruth
2015-01-01
MOTIVATION: Discrimination statistics describe the ability of a survival model to assign higher risks to individuals who experience earlier events: examples are Harrell's C-index and Royston and Sauerbrei's D, which we call the D-index. Prognostic covariates whose distributions are controlled...... statistics in censored survival data. OBJECTIVE: To develop extensions of the C-index and D-index that describe the prognostic ability of a model adjusted for one or more covariate(s). METHOD: We define a covariate-adjusted C-index and D-index for censored survival data, propose several estimators...... by the study design (e.g. age and sex) influence discrimination and can make it difficult to compare model discrimination between studies. Although covariate adjustment is a standard procedure for quantifying disease-risk factor associations, there are no covariate adjustment methods for discrimination...
AFCI-2.0 Library of Neutron Cross Section Covariances
Energy Technology Data Exchange (ETDEWEB)
Herman, M.; Herman,M.; Oblozinsky,P.; Mattoon,C.; Pigni,M.; Hoblit,S.; Mughabghab,S.F.; Sonzogni,A.; Talou,P.; Chadwick,M.B.; Hale.G.M.; Kahler,A.C.; Kawano,T.; Little,R.C.; Young,P.G.
2011-06-26
Neutron cross section covariance library has been under development by BNL-LANL collaborative effort over the last three years. The primary purpose of the library is to provide covariances for the Advanced Fuel Cycle Initiative (AFCI) data adjustment project, which is focusing on the needs of fast advanced burner reactors. The covariances refer to central values given in the 2006 release of the U.S. neutron evaluated library ENDF/B-VII. The preliminary version (AFCI-2.0beta) has been completed in October 2010 and made available to the users for comments. In the final 2.0 release, covariances for a few materials were updated, in particular new LANL evaluations for {sup 238,240}Pu and {sup 241}Am were adopted. BNL was responsible for covariances for structural materials and fission products, management of the library and coordination of the work, while LANL was in charge of covariances for light nuclei and for actinides.
Shrinkage Estimation of the Power Spectrum Covariance Matrix
Pope, Adrian C
2007-01-01
We introduce a novel statistical technique, shrinkage estimation, to estimate the power spectrum covariance matrix from a limited number of simulations. We optimally combine an empirical estimate of the covariance with a model (the target) to minimize the total mean squared error compared to the true underlying covariance. We test our technique on N-body simulations and evaluate its performance by estimating cosmological parameters. Using a simple diagonal target, we show that the shrinkage estimator significantly outperforms both the empirical covariance and the target individually when using a small number of simulations. We find that reducing noise in the covariance estimate is essential for properly estimating the values of cosmological parameters as well as their confidence intervals. We extend our method to the jackknife covariance estimator and again find significant improvement, though simulations give better results. Even for thousands of simulations we still find evidence that our method improves es...
Generally Covariant Actions for Multiple D-branes
Brecher, Dominic; Furuuchi, Kazuyuki; Ling, Henry; Raamsdonk, Mark
2004-01-01
We develop a formalism that allows us to write actions for multiple D-branes with manifest general covariance. While the matrix coordinates of the D-branes have a complicated transformation law under coordinate transformations, we find that these may be promoted to (redundant) matrix fields on the transverse space with a simple covariant transformation law. Using these fields, we define a covariant distribution function (a matrix generalization of the delta function which describes the locati...
Orthogonal versus covariant Lyapunov vectors for rough hard disk systems
Bosetti, Hadrien; Posch, Harald A.
2011-01-01
The Oseledec splitting of the tangent space into covariant subspaces for a hyperbolic dynamical system is numerically accessible by computing the full set of covariant Lyapunov vectors. In this paper, the covariant Lyapunov vectors, the orthogonal Gram-Schmidt vectors, and the corresponding local (time-dependent) Lyapunov exponents, are analyzed for a planar system of rough hard disks (RHDS). These results are compared to respective results for a smooth-hard-disk system (SHDS). We find that t...
A scale invariant covariance structure on jet space
DEFF Research Database (Denmark)
Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo
2005-01-01
This paper considers scale invariance of statistical image models. We study statistical scale invariance of the covariance structure of jet space under scale space blurring and derive the necessary structure and conditions of the jet covariance matrix in order for it to be scale invariant. As part...... results where we estimate the scale invariant jet covariance of natural images and show that it resembles that of Brownian images....
Holographic bound in covariant loop quantum gravity
Tamaki, Takashi
2016-01-01
We investigate puncture statistics based on the covariant area spectrum in loop quantum gravity. First, we consider Maxwell-Boltzmann statistics with a Gibbs factor for punctures. We establish formulae which relate physical quantities such as horizon area to the parameter characterizing holographic degrees of freedom. We also perform numerical calculations and obtain consistency with these formulae. These results tell us that the holographic bound is satisfied in the large area limit and correction term of the entropy-area law can be proportional to the logarithm of the horizon area. Second, we also consider Bose-Einstein statistics and show that the above formulae are also useful in this case. By applying the formulae, we can understand intrinsic features of Bose-Einstein condensate which corresponds to the case when the horizon area almost consists of punctures in the ground state. When this phenomena occurs, the area is approximately constant against the parameter characterizing the temperature. When this ...
Covariant derivation of tunneling across horizons
Vanzo, Luciano
2011-01-01
The tunneling method for stationary black holes in the Hamilton-Jacobi variant is reconsidered in the light of various critiques that have been moved against. It is shown that once the tunneling trajectories have been correctly identified the method is totally free from internal inconsistencies, it is manifestly covariant, it allows for the extension to spinning particles and it can even be used without solving the Hamilton-Jacobi equation. These conclusions borrow support on a simplified proof of the Hartle and Hawking analytic continuation of the propagator, made possible by the unique assumption that the classical action be analytic in complexified Schwarzschild spacetime. A more general version of the Parikh-Wilczek method will also be proposed along these lines.
Super-Sample Covariance in Simulations
Li, Yin; Takada, Masahiro
2014-01-01
Using separate universe simulations, we accurately quantify super-sample covariance (SSC), the typically dominant sampling error for matter power spectrum estimators in a finite volume, which arises from the presence of super survey modes. By quantifying the power spectrum response to a background mode, this approach automatically captures the separate effects of beat coupling in the quasilinear regime, halo sample variance in the nonlinear regime and a new dilation effect which changes scales in the power spectrum coherently across the survey volume, including the baryon acoustic oscillation scale. It models these effects at typically the few percent level or better with a handful of small volume simulations for any survey geometry compared with directly using many thousands of survey volumes in a suite of large volume simulations. The stochasticity of the response is sufficiently small that in the quasilinear regime, SSC can be alternately included by fitting the mean density in the volume with these fixed ...
Covariant Lyapunov analysis of chaotic Kolmogorov flows.
Inubushi, Masanobu; Kobayashi, Miki U; Takehiro, Shin-ichi; Yamada, Michio
2012-01-01
Hyperbolicity is an important concept in dynamical system theory; however, we know little about the hyperbolicity of concrete physical systems including fluid motions governed by the Navier-Stokes equations. Here, we study numerically the hyperbolicity of the Navier-Stokes equation on a two-dimensional torus (Kolmogorov flows) using the method of covariant Lyapunov vectors developed by Ginelli et al. [Phys. Rev. Lett. 99, 130601 (2007)]. We calculate the angle between the local stable and unstable manifolds along an orbit of chaotic solution to evaluate the hyperbolicity. We find that the attractor of chaotic Kolmogorov flows is hyperbolic at small Reynolds numbers, but that smaller angles between the local stable and unstable manifolds are observed at larger Reynolds numbers, and the attractor appears to be nonhyperbolic at a certain Reynolds numbers. Also, we observed some relations between these hyperbolic properties and physical properties such as time correlation of the vorticity and the energy dissipation rate.
Covariant density functional theory for magnetic rotation
Peng, J.; Meng, J.; Ring, P.; Zhang, S. Q.
2008-08-01
The tilted axis cranking formalism is implemented in relativistic mean field (RMF) theory. It is used for a microscopic description of magnetic rotation in the framework of covariant density functional theory. We assume that the rotational axis is in the xz plane and consider systems with the two symmetries P (space reflection) and PyT (a combination of a reflection in the y direction and time reversal). A computer code based on these symmetries is developed, and first applications are discussed for the nucleus Gd142: the rotational band based on the configuration πh11/22⊗νh11/2-2 is investigated in a fully microscopic and self-consistent way. The results are compared with available data, such as spectra and electromagnetic transition ratios B(M1)/B(E2). The relation between rotational velocity and angular momentum are discussed in detail together with the shears mechanism characteristic of magnetic rotation.
Nuclear landscape in covariant density functional theory
International Nuclear Information System (INIS)
The neutron and proton drip lines represent the limits of the nuclear landscape. While the proton drip line is measured experimentally up to rather high Z values, the location of the neutron drip line for absolute majority of elements is based on theoretical predictions which involve extreme extrapolations. The first ever systematic investigation of the location of the proton and neutron drip lines in the covariant density functional theory has been performed by employing a set of the state-of-the-art parametrizations. Calculated theoretical uncertainties in the position of two-neutron drip line are compared with those obtained in non-relativistic DFT calculations. Shell effects drastically affect the shape of two-neutron drip line. In particular, model uncertainties in the definition of two-neutron drip line at Z∼54, N=126 and Z∼82, N=184 are very small due to the impact of spherical shell closures at N=126 and 184
Covariant Hyperbolization of Force-free Electrodynamics
Carrasco, Federico
2016-01-01
Force-Free Flectrodynamics (FFE) is a non-linear system of equations modeling the evolution of the electromagnetic field, in the presence of a magnetically dominated relativistic plasma. This configuration arises on several astrophysical scenarios, which represent exciting laboratories to understand physics in extreme regimes. We show that this system, when restricted to the correct constraint submanifold, is symmetric hyperbolic. In numerical applications is not feasible to keep the system in that submanifold, and so, it is necessary to analyze its structure first in the tangent space of that submanifold and then in a whole neighborhood of it. As already shown by Pfeiffer, a direct (or naive) formulation of this system (in the whole tangent space) results in a weakly hyperbolic system of evolution equations for which well-possednes for the initial value formulation does not follows. Using the generalized symmetric hyperbolic formalism due to Geroch, we introduce here a covariant hyperbolization for the FFE s...
Universal Gravitation as Lorentz-covariant Dynamics
Kauffmann, Steven Kenneth
2014-01-01
Einstein's equivalence principle implies that the acceleration of a particle in a "specified" gravitational field is independent of its mass. While this is certainly true to great accuracy for bodies we observe in the Earth's gravitational field, a hypothetical body of mass comparable to the Earth's would perceptibly cause the Earth to fall toward it, which would feed back into the strength as a function of time of the Earth's gravitational field affecting that body. In short, Einstein's equivalence principle isn't exact, but is an approximation that ignores recoil of the "specified" gravitational field, which sheds light on why general relativity has no clearly delineated native embodiment of conserved four-momentum. Einstein's 1905 relativity of course doesn't have the inexactitudes he unwittingly built into GR, so it is natural to explore a Lorentz-covariant gravitational theory patterned directly on electromagnetism, wherein a system's zero-divergence overall stress-energy, including all gravitational fee...
Baryon Spectrum Analysis using Covariant Constraint Dynamics
Whitney, Joshua; Crater, Horace
2012-03-01
The energy spectrum of the baryons is determined by treating each of them as a three-body system with the interacting forces coming from a set of two-body potentials that depend on both the distance between the quarks and the spin and orbital angular momentum coupling terms. The Two Body Dirac equations of constraint dynamics derived by Crater and Van Alstine, matched with the quasipotential formalism of Todorov as the underlying two-body formalism are used, as well as the three-body constraint formalism of Sazdjian to integrate the three two-body equations into a single relativistically covariant three body equation for the bound state energies. The results are analyzed and compared to experiment using a best fit method and several different algorithms, including a gradient approach, and Monte Carlo method. Results for all well-known baryons are presented and compared to experiment, with good accuracy.
Flavour Covariant Formalism for Resonant Leptogenesis
Dev, P S Bhupal; Pilaftsis, Apostolos; Teresi, Daniele
2014-01-01
We present a fully flavour-covariant formalism for transport phenomena and apply it to study the flavour-dynamics of Resonant Leptogenesis (RL). We show that this formalism provides a complete and unified description of RL, consistently accounting for three distinct physical phenomena: (i) resonant mixing and (ii) coherent oscillations between different heavy-neutrino flavours, as well as (iii) quantum decoherence effects in the charged-lepton sector. We describe the necessary emergence of higher-rank tensors in flavour space, arising from the unitarity cuts of partial self-energies. Finally, we illustrate the importance of this formalism within a minimal Resonant $\\tau$-Genesis model by showing that, with the inclusion of all flavour effects in a consistent way, the final lepton asymmetry can be enhanced by up to an order of magnitude, when compared to previous partially flavour-dependent treatments.
Covariance of Lucky Images: Performance analysis
Cagigal, Manuel P.; Valle, Pedro J.; Cagigas, Miguel A.; Villó-Pérez, Isidro; Colodro-Conde, Carlos; Ginski, C.; Mugrauer, M.; Seeliger, M.
2016-09-01
The covariance of ground-based Lucky Images (COELI) is a robust and easy-to-use algorithm that allows us to detect faint companions surrounding a host star. In this paper we analyze the relevance of the number of processed frames, the frames quality, the atmosphere conditions and the detection noise on the companion detectability. This analysis has been carried out using both experimental and computer simulated imaging data. Although the technique allows us the detection of faint companions, the camera detection noise and the use of a limited number of frames reduce the minimum detectable companion intensity to around 1000 times fainter than that of the host star when placed at an angular distance corresponding to the few first Airy rings. The reachable contrast could be even larger when detecting companions with the assistance of an adaptive optics system.
Supergeometry in locally covariant quantum field theory
Hack, Thomas-Paul; Schenkel, Alexander
2015-01-01
In this paper we analyze supergeometric locally covariant quantum field theories. We develop suitable categories SLoc of super-Cartan supermanifolds, which generalize Lorentz manifolds in ordinary quantum field theory, and show that, starting from a few representation theoretic and geometric data, one can construct a functor A : SLoc --> S*Alg to the category of super-*-algebras which can be interpreted as a non-interacting super-quantum field theory. This construction turns out to disregard supersymmetry transformations as the morphism sets in the above categories are too small. We then solve this problem by using techniques from enriched category theory, which allows us to replace the morphism sets by suitable morphism supersets that contain supersymmetry transformations as their higher superpoints. We construct super-quantum field theories in terms of enriched functors eA : eSLoc --> eS*Alg between the enriched categories and show that supersymmetry transformations are appropriately described within the en...
A taxonomic study of Bali and Lombok Begonia (Begoniaceae
Directory of Open Access Journals (Sweden)
Deden Girmansyah
2009-12-01
Full Text Available GIRMANSYAH, DEDEN. 2009. A taxonomic study of Bali and Lombok Begonia (Begoniaceae. Reinwardtia 12(5: 419–434. — A taxonomic study of Bali and Lombok Begonia was based on an investigation of morphological characters from 60 specimens in Herbarium Bogoriense. This study shows that there are 8 species that can be recognized: three species already in the genus (Begonia coriacea, B. longifolia, and B. tenuifolia and five new (Begonia baliensis, B. lempuyangensis, B. pseudomuricata, B. multibracteata, and B. lombokensis.
Summary report of technical meeting on neutron cross section covariances
International Nuclear Information System (INIS)
A summary is given of the Technical Meeting on Neutron Cross Section Covariances. The meeting goal was to assess covariance data needs and recommend appropriate methodologies to address those needs. Discussions on covariance data focused on three general topics: 1) Resonance and unresolved resonance regions; 2) Fast neutron region; and 3) Users' perspective: benchmarks' uncertainty and reactor dosimetry. A number of recommendations for further work were generated and the important work that remains to be done in the field of covariances was identified. (author)
Validity of covariance models for the analysis of geographical variation
DEFF Research Database (Denmark)
Guillot, Gilles; Schilling, Rene L.; Porcu, Emilio;
2014-01-01
1. Due to the availability of large molecular data-sets, covariance models are increasingly used to describe the structure of genetic variation as an alternative to more heavily parametrised biological models. 2. We focus here on a class of parametric covariance models that received sustained...... attention lately and show that the conditions under which they are valid mathematical models have been overlooked so far. 3. We provide rigorous results for the construction of valid covariance models in this family. 4. We also outline how to construct alternative covariance models for the analysis...
Managing hazardous pollutants in Chile: arsenic.
Sancha, Ana María; O'Ryan, Raul
2008-01-01
Chile is one of the few countries that faces the environmental challenge posed by extensive arsenic pollution, which exists in the northern part of the country. Chile has worked through various options to appropriately address the environmental challenge of arsenic pollution of water and air. Because of cost and other reasons, copying standards used elsewhere in the world was not an option for Chile. Approximately 1.8 million people, representing about 12% of the total population of the country, live in arsenic-contaminated areas. In these regions, air, water, and soil are contaminated with arsenic from both natural and anthropogenic sources. For long periods, water consumed by the population contained arsenic levels that exceeded values recommended by the World Health Organization. Exposure to airborne arsenic also occurred near several large cities, as a consequence of both natural contamination and the intensive mining activity carried out in those areas. In rural areas, indigenous populations, who lack access to treated water, were also exposed to arsenic by consuming foods grown locally in arsenic-contaminated soils. Health effects in children and adults from arsenic exposure first appeared in the 1950s. Such effects included vascular, respiratory, and skin lesions from intake of high arsenic levels in drinking water. Methods to remove arsenic from water were evaluated, developed, and implemented that allowed significant reductions in exposure at a relatively low cost. Construction and operation of treatment plants to remove arsenic from water first began in the 1970s. Beginning in the 1990s, epidemiological studies showed that the rate of lung and bladder cancer in the arsenic-polluted area was considerably higher than mean cancer rates for the country. Cancer incidence was directly related to arsenic exposure. During the 1990s, international pressure and concern by Chile's Health Ministry prompted action to regulate arsenic emissions from copper smelters. A
Khoury, Justin; Tolley, Andrew J
2014-01-01
Traditional derivations of general relativity from the graviton degrees of freedom assume space-time Lorentz covariance as an axiom. In this essay, we survey recent evidence that general relativity is the unique spatially-covariant effective field theory of the transverse, traceless graviton degrees of freedom. The Lorentz covariance of general relativity, having not been assumed in our analysis, is thus plausibly interpreted as an accidental or emergent symmetry of the gravitational sector. From this point of view, Lorentz covariance is a necessary feature of low-energy graviton dynamics, not a property of space-time. This result has revolutionary implications for fundamental physics.
Animal migration: linking models and data beyond taxonomic limits
Bauer, Silke; Barta Zoltán (1967-) (biológus, zoológus); Ens, Bruno J.; Hays, Graeme C.; McNamara, John M; Klaassen, Marcel
2009-01-01
An international workshop on animal migration was held at the Lorentz Center in Leiden, The Netherlands, 2–6 March 2009, bringing together leading theoreticians and empiricists from the major migratory taxa, aiming at the identification of cutting-edge questions in migration research that cross taxonomic borders.
Developing green supply chain management strategies: A taxonomic approach
Directory of Open Access Journals (Sweden)
Michael Mutingi
2013-06-01
Full Text Available Purpose: The objective of this research is to explore the empirical green supply chain activities found in literature, and to develop a taxonomic framework that can be used for formulating appropriate strategies for green supply chains, based on characteristic dimensions for the green supply chain. Design/methodology/approach: The taxonomic framework is developed through (i analysis of green supply chain activities found in existing empirical work or case studies recorded in literature, (ii identification of key dimensions that influence green supply chain management strategies, and (iii development of a taxonomic scheme for selecting or developing green strategies. Findings: The paper finds that this study yielded: a set of three characteristic dimensions that influence strategic green supply chain management, and a guided structured approach selecting appropriate green strategies, providing managerial insights. Research limitations/implications: This paper shows that future work includes development of specific performance management indices according to the taxonomy of green strategies developed in this study. Practical implications: This research provided a practical guided approach that enhances appropriate formulation of green strategies for green supply chain management, while providing sound managerial insights for the supply chain decision maker. The choice of supply chain strategy directly impacts the overall environmental, economic and operations performance of the supply chain. Originality/value: This study presents to supply chain decision makers a new taxonomic framework that simplifies and enhances the formulation of green strategies, and to researchers a comparative understanding of various strategies applicable to green supply chains.
WEVOTE: Weighted Voting Taxonomic Identification Method of Microbial Sequences
Metwally, Ahmed A.; Dai, Yang; Finn, Patricia W.; Perkins, David L.
2016-01-01
Background Metagenome shotgun sequencing presents opportunities to identify organisms that may prevent or promote disease. The analysis of sample diversity is achieved by taxonomic identification of metagenomic reads followed by generating an abundance profile. Numerous tools have been developed based on different design principles. Tools achieving high precision can lack sensitivity in some applications. Conversely, tools with high sensitivity can suffer from low precision and require long computation time. Methods In this paper, we present WEVOTE (WEighted VOting Taxonomic idEntification), a method that classifies metagenome shotgun sequencing DNA reads based on an ensemble of existing methods using k-mer-based, marker-based, and naive-similarity based approaches. Our evaluation on fourteen benchmarking datasets shows that WEVOTE improves the classification precision by reducing false positive annotations while preserving a high level of sensitivity. Conclusions WEVOTE is an efficient and automated tool that combines multiple individual taxonomic identification methods to produce more precise and sensitive microbial profiles. WEVOTE is developed primarily to identify reads generated by MetaGenome Shotgun sequencing. It is expandable and has the potential to incorporate additional tools to produce a more accurate taxonomic profile. WEVOTE was implemented using C++ and shell scripting and is available at www.github.com/aametwally/WEVOTE. PMID:27683082
Taxonomical and functional microbial community selection in soybean rhizosphere
Mendes, L.W.; Kuramae, E.E.; Navarrete, A.A.; Van Veen, J.A.; Tsai, S.M.
2014-01-01
This study addressed the selection of the rhizospheric microbial community from the bulk soil reservoir under agricultural management of soybean in Amazon forest soils. We used a shotgun metagenomics approach to investigate the taxonomic and functional diversities of microbial communities in the bul
Covariance of lichen and vascular plant floras
Bennett, J.P.; Wetmore, C.M.
1999-01-01
The geographic relationships among taxonomic groups are important to study to determine patterns of biodiversity and whether or not associations occur between large groups, e.g., birds and vascular plants. This study was undertaken to determine relationships between higher plants and lower plants, specifically vascular plant and lichen floras in nine national parks of the Great Lakes region. No significant relationship was found between vascular plant floras and lichen floras in this area, which spans 1200 km longitudinally, or between an additional 19 areas from North America that were less than 1000 km(2) in area. For areas larger than 1000 km(2), however, a significant positive relationship existed for 33 areas that span one to approximately 150 million km(2). The ratio of numbers of vascular plants to lichens appeared to average just over 6 across the 33 areas. In the Great Lakes parks, between 28-30% of either the vascular plant or lichen species were singletons (occurring in only one park), but the parks that contained the most singletons were not congruent: Isle Royale had the most singleton lichens, while Indiana Dunes had the most vascular plant singletons. Fewer lichen species (2%) than vascular plants (4%) occurred in all nine parks. Latitude appeared to explain some of the variation between the two groups: vascular plants decreased with increasing latitude, while lichens increased.
Conditioning of radium sources in Chile
International Nuclear Information System (INIS)
A process experimented in Chile to conditioning Ra-226 sources arising as waste from medical uses in Chile is described. The IAEA offered to participate in the Project for Conditioning Radium Sources in order to place all the radium sources in the country under an internationally accepted standard. These sources hare those that have been used in medical applications for many years. The CCHEN made its own modifications to the project's execution by using its own infrastructure and scientific and technical skill in this field. For this purpose, the CCHEN uses the human resources and facilities of the Radioactive Waste Management Unit (UGDR) and acquires materials that are commercially available in the country. IAEA assistance focused on quality assurance, so they supply all expensive items which the UGDR, cannot access, plus they certify the quality of the conditioned products. This assistance is achieved through the approval of procedures and methodologies based on those that are recommended
Bibliothekswesen in Südamerika - Chile im Jahr 2014
Schultheis, Alexander H. T.
2014-01-01
Librarianship in South America - Chile in 2014 (translation of the title). The historian and librarian Alexander H.T. Schultheis is living since nine years in Santiago de Chile and he is observing the Chilean librarianship. Although Chile is doing well economically, no improvement can be seen in the field of culture and education. On the contrary, the public libraries are still poorly equipped. Chance can be seen as small bright spots on the horizon, for example, the new opened cultural cente...
Movilidad intrageneracional del ingreso en Chile
Claudio, Sapelli
2013-01-01
This paper estimates the different intra-generational mobility indicators for Chile on the basis of the Casen panel. Conclusions from the literature are evaluated in light of results that are based mainly on a discussion of the transition matrix. It is concluded that there is a mistaken interpretation of the data in part of the literature. A simulation is made that demonstrates that the Chilean transition matrix could be the consequence of random shocks to the effective distribution of income...
Unmarried cohabitation among deprived families in Chile
Ramm Santelices, Alejandra Margarita
2013-01-01
It is clear that unmarried cohabitation is increasing in Chile. It is less clear what unmarried cohabitation is and why is it rising. In Latin America cohabitation is common among low income groups, and has been described as a surrogate marriage for the disadvantaged. Cohabitation in the region entails conventional gender roles and having children. It has been explained by colonial dominance, poverty, kinship, and machismo. The evidence amassed here indicates that although in practice cohabit...
Theory of Covariance Equivalent ARMAV Models of Civil Engineering Structures
DEFF Research Database (Denmark)
Andersen, P.; Brincker, Rune; Kirkegaard, Poul Henning
In this paper the theoretical background for using covariance equivalent ARMAV models in modal analysis is discussed. It is shown how to obtain a covariance equivalent ARMA model for a univariate linear second order continuous-time system excited by Gaussian white noise. This result is generalize...
Theory of Covariance Equivalent ARMAV Models of Civil Engineering Structures
DEFF Research Database (Denmark)
Andersen, P.; Brincker, Rune; Kirkegaard, Poul Henning
1996-01-01
In this paper the theoretical background for using covariance equivalent ARMAV models in modal analysis is discussed. It is shown how to obtain a covariance equivalent ARMA model for a univariate linear second order continous-time system excited by Gaussian white noise. This result is generalized...
Gauge independence as a consequence of gauge covariance
International Nuclear Information System (INIS)
Gauge independence of a physical S-matrix is proved without perturbation in a satisfactory gauge-field theory with gauge covariance. The proof goes through both for Abelian and non-Abelian cases, and the independence is a consequence of gauge covariance and asymptotic completeness. (auth.)
On the bilinear covariants associated to mass dimension one spinors
da Silva, J M Hoff; Rogerio, R J Bueno; Scatena, E
2016-01-01
In this paper we approach the issue of Clifford algebra basis deformation, allowing for bilinear covariants associated to Elko spinors which satisfy the Fierz-Pauli-Kofink identities. We present a complete analysis of covariance, taking into account the involved dual structure associated to Elko. Moreover, the possible generalizations to the recently presented new dual structure are performed.
Reality conditions for Ashtekar gravity from Lorentz-covariant formulation
Alexandrov, Sergei
2005-01-01
We show the equivalence of the Lorentz-covariant canonical formulation considered for the Immirzi parameter $\\beta=i$ to the selfdual Ashtekar gravity. We also propose to deal with the reality conditions in terms of Dirac brackets derived from the covariant formulation and defined on an extended phase space which involves, besides the selfdual variables, also their anti-selfdual counterparts.
Handling Correlations between Covariates and Random Slopes in Multilevel Models
Bates, Michael David; Castellano, Katherine E.; Rabe-Hesketh, Sophia; Skrondal, Anders
2014-01-01
This article discusses estimation of multilevel/hierarchical linear models that include cluster-level random intercepts and random slopes. Viewing the models as structural, the random intercepts and slopes represent the effects of omitted cluster-level covariates that may be correlated with included covariates. The resulting correlations between…
The K-Step Spatial Sign Covariance Matrix
Croux, C.; Dehon, C.; Yadine, A.
2010-01-01
The Sign Covariance Matrix is an orthogonal equivariant estimator of mul- tivariate scale. It is often used as an easy-to-compute and highly robust estimator. In this paper we propose a k-step version of the Sign Covariance Matrix, which improves its e±ciency while keeping the maximal breakdown poin
Alternative Multiple Imputation Inference for Mean and Covariance Structure Modeling
Lee, Taehun; Cai, Li
2012-01-01
Model-based multiple imputation has become an indispensable method in the educational and behavioral sciences. Mean and covariance structure models are often fitted to multiply imputed data sets. However, the presence of multiple random imputations complicates model fit testing, which is an important aspect of mean and covariance structure…
Newton law in covariant unimodular $F(R)$ gravity
Nojiri, S; Oikonomou, V K
2016-01-01
We propose a covariant ghost-free unimodular $F(R)$ gravity theory, which contains a three-form field and study its structure using the analogy of the proposed theory with a quantum system which describes a charged particle in uniform magnetic field. Newton's law in non-covariant unimodular $F(R)$ gravity as well as in unimodular Einstein gravity is derived and it is shown to be just the same as in General Relativity. The derivation of Newton's law in covariant unimodular $F(R)$ gravity shows that it is modified precisely in the same way as in the ordinary $F(R)$ theory. We also demonstrate that the cosmology of a Friedmann-Robertson-Walker background, is equivalent in the non-covariant and covariant formulations of unimodular $F(R)$ theory.
Modular covariance and the algebraic PCT/spin-statistics theorem
Davidson, D R
1995-01-01
In the theory of nets of observable algebras, the modular operators associated with wedge regions are expected to have a natural geometric action, a generalization of the Bisognano-Wichmann condition for nets associated with Poincare-covariant fields. Here many possible such modular covariance conditions are discussed (in spacetime of at least three dimensions), including several conditions previously proposed and known to imply versions of the PCT and spin-statistics theorems. The logical relations between these conditions are explored: for example, it is shown that most of them are equivalent, and that all of them follow from appropriate commutation relations for the modular automorphisms alone. These results allow us to reduce the study of modular covariance to the case of systems describing non-interacting particles. Given finitely many Poincare-covariant non-interacting particles of any given mass, it is shown that modular covariance and wedge duality must hold, and the modular operators for wedge region...
Gaussian covariance matrices for anisotropic galaxy clustering measurements
Grieb, Jan Niklas; Salazar-Albornoz, Salvador; Vecchia, Claudio dalla
2015-01-01
Measurements of the redshift-space galaxy clustering have been a prolific source of cosmological information in recent years. In the era of precision cosmology, accurate covariance estimates are an essential step for the validation of galaxy clustering models of the redshift-space two-point statistics. For cases where only a limited set of simulations is available, assessing the data covariance is not possible or only leads to a noisy estimate. Also, relying on simulated realisations of the survey data means that tests of the cosmology dependence of the covariance are expensive. With these two points in mind, this work aims at presenting a simple theoretical model for the linear covariance of anisotropic galaxy clustering observations with synthetic catalogues. Considering the Legendre moments (`multipoles') of the two-point statistics and projections into wide bins of the line-of-sight parameter (`clustering wedges'), we describe the modelling of the covariance for these anisotropic clustering measurements f...
UDU/T/ covariance factorization for Kalman filtering
Thornton, C. L.; Bierman, G. J.
1980-01-01
There has been strong motivation to produce numerically stable formulations of the Kalman filter algorithms because it has long been known that the original discrete-time Kalman formulas are numerically unreliable. Numerical instability can be avoided by propagating certain factors of the estimate error covariance matrix rather than the covariance matrix itself. This paper documents filter algorithms that correspond to the covariance factorization P = UDU(T), where U is a unit upper triangular matrix and D is diagonal. Emphasis is on computational efficiency and numerical stability, since these properties are of key importance in real-time filter applications. The history of square-root and U-D covariance filters is reviewed. Simple examples are given to illustrate the numerical inadequacy of the Kalman covariance filter algorithms; these examples show how factorization techniques can give improved computational reliability.
High-dimensional covariance matrix estimation in approximate factor models
Fan, Jianqing; Mincheva, Martina; 10.1214/11-AOS944
2012-01-01
The variance--covariance matrix plays a central role in the inferential theories of high-dimensional factor models in finance and economics. Popular regularization methods of directly exploiting sparsity are not directly applicable to many financial problems. Classical methods of estimating the covariance matrices are based on the strict factor models, assuming independent idiosyncratic components. This assumption, however, is restrictive in practical applications. By assuming sparse error covariance matrix, we allow the presence of the cross-sectional correlation even after taking out common factors, and it enables us to combine the merits of both methods. We estimate the sparse covariance using the adaptive thresholding technique as in Cai and Liu [J. Amer. Statist. Assoc. 106 (2011) 672--684], taking into account the fact that direct observations of the idiosyncratic components are unavailable. The impact of high dimensionality on the covariance matrix estimation based on the factor structure is then studi...
Time-dependent spherically symmetric covariant Galileons
Babichev, Eugeny
2012-01-01
We study spherically symmetric solutions of the cubic covariant Galileon model in curved spacetime in presence of a matter source, in the test scalar field approximation. We show that a cosmological time evolution of the Galileon field gives rise to an induced matter-scalar coupling, due to the Galileon-graviton kinetic braiding, therefore the solution for the Galileon field is non trivial even if the bare matter-scalar coupling constant is set to zero. The local solution crucially depends on the asymptotic boundary conditions, and in particular, Minkowski and de Sitter asymptotics correspond to different branches of the solution. We study the stability of these solutions, namely, the well-posedness of the Cauchy problem and the positivity of energy for scalar and tensor perturbations, by diagonalizing the kinetic terms of the spin-2 and spin-0 degrees of freedom. In addition, we find that in presence of a cosmological time evolution of the Galileon field, its kinetic mixing with the graviton leads to a frict...
Historical Hamiltonian Dynamics: symplectic and covariant
Lachieze-Rey, M
2016-01-01
This paper presents a "historical" formalism for dynamical systems, in its Hamiltonian version (Lagrangian version was presented in a previous paper). It is universal, in the sense that it applies equally well to time dynamics and to field theories on space-time. It is based on the notion of (Hamiltonian) histories, which are sections of the (extended) phase space bundle. It is developed in the space of sections, in contradistinction with the usual formalism which works in the bundle manifold. In field theories, the formalism remains covariant and does not require a spitting of space-time. It considers space-time exactly in the same manner than time in usual dynamics, both being particular cases of the evolution domain. It applies without modification when the histories (the fields) are forms rather than scalar functions, like in electromagnetism or in tetrad general relativity. We develop a differential calculus in the infinite dimensional space of histories. It admits a (generalized) symplectic form which d...
Supergeometry in Locally Covariant Quantum Field Theory
Hack, Thomas-Paul; Hanisch, Florian; Schenkel, Alexander
2016-03-01
In this paper we analyze supergeometric locally covariant quantum field theories. We develop suitable categories SLoc of super-Cartan supermanifolds, which generalize Lorentz manifolds in ordinary quantum field theory, and show that, starting from a few representation theoretic and geometric data, one can construct a functor A : SLoc to S* Alg to the category of super-*-algebras, which can be interpreted as a non-interacting super-quantum field theory. This construction turns out to disregard supersymmetry transformations as the morphism sets in the above categories are too small. We then solve this problem by using techniques from enriched category theory, which allows us to replace the morphism sets by suitable morphism supersets that contain supersymmetry transformations as their higher superpoints. We construct super-quantum field theories in terms of enriched functors eA : eSLoc to eS* Alg between the enriched categories and show that supersymmetry transformations are appropriately described within the enriched framework. As examples we analyze the superparticle in 1|1-dimensions and the free Wess-Zumino model in 3|2-dimensions.
Generalized Covariant Gyrokinetic Dynamics of Magnetoplasmas
International Nuclear Information System (INIS)
A basic prerequisite for the investigation of relativistic astrophysical magnetoplasmas, occurring typically in the vicinity of massive stellar objects (black holes, neutron stars, active galactic nuclei, etc.), is the accurate description of single-particle covariant dynamics, based on gyrokinetic theory (Beklemishev et al., 1999-2005). Provided radiation-reaction effects are negligible, this is usually based on the assumption that both the space-time metric and the EM fields (in particular the magnetic field) are suitably prescribed and are considered independent of single-particle dynamics, while allowing for the possible presence of gravitational/EM perturbations driven by plasma collective interactions which may naturally arise in such systems. The purpose of this work is the formulation of a generalized gyrokinetic theory based on the synchronous variational principle recently pointed out (Tessarotto et al., 2007) which permits to satisfy exactly the physical realizability condition for the four-velocity. The theory here developed includes the treatment of nonlinear perturbations (gravitational and/or EM) characterized locally, i.e., in the rest frame of a test particle, by short wavelength and high frequency. Basic feature of the approach is to ensure the validity of the theory both for large and vanishing parallel electric field. It is shown that the correct treatment of EM perturbations occurring in the presence of an intense background magnetic field generally implies the appearance of appropriate four-velocity corrections, which are essential for the description of single-particle gyrokinetic dynamics.
Holographic bound in covariant loop quantum gravity
Tamaki, Takashi
2016-07-01
We investigate puncture statistics based on the covariant area spectrum in loop quantum gravity. First, we consider Maxwell-Boltzmann statistics with a Gibbs factor for punctures. We establish formulas which relate physical quantities such as horizon area to the parameter characterizing holographic degrees of freedom. We also perform numerical calculations and obtain consistency with these formulas. These results tell us that the holographic bound is satisfied in the large area limit and the correction term of the entropy-area law can be proportional to the logarithm of the horizon area. Second, we also consider Bose-Einstein statistics and show that the above formulas are also useful in this case. By applying the formulas, we can understand intrinsic features of Bose-Einstein condensate which corresponds to the case when the horizon area almost consists of punctures in the ground state. When this phenomena occurs, the area is approximately constant against the parameter characterizing the temperature. When this phenomena is broken, the area shows rapid increase which suggests the phase transition from quantum to classical area.
Into the Bulk: A Covariant Approach
Engelhardt, Netta
2016-01-01
I propose a general, covariant way of defining when one region is "deeper in the bulk" than another. This definition is formulated outside of an event horizon (or in the absence thereof) in generic geometries; it may be applied to both points and surfaces, and may be used to compare the depth of bulk points or surfaces relative to a particular boundary subregion or relative to the entire boundary. Using the recently proposed "lightcone cut" formalism, the comparative depth between two bulk points can be determined from the singularity structure of Lorentzian correlators in the dual field theory. I prove that, by this definition, causal wedges of progressively larger regions probe monotonically deeper in the bulk. The definition furthermore matches expectations in pure AdS and in static AdS black holes with isotropic spatial slices, where a well-defined holographic coordinate exists. In terms of holographic RG flow, this new definition of bulk depth makes contact with coarse-graining over both large distances ...
IMPROVED COVARIANCE DRIVEN BLIND SUBSPACE IDENTIFICATION METHOD
Institute of Scientific and Technical Information of China (English)
ZHANG Zhiyi; FAN Jiangling; HUA Hongxing
2006-01-01
An improved covariance driven subspace identification method is presented to identify the weakly excited modes. In this method, the traditional Hankel matrix is replaced by a reformed one to enhance the identifiability of weak characteristics. The robustness of eigenparameter estimation to noise contamination is reinforced by the improved Hankel matrix. In combination with component energy index (CEI) which indicates the vibration intensity of signal components, an alternative stabilization diagram is adopted to effectively separate spurious and physical modes. Simulation of a vibration system of multiple-degree-of-freedom and experiment of a frame structure subject to wind excitation are presented to demonstrate the improvement of the proposed blind method. The performance of this blind method is assessed in terms of its capability in extracting the weak modes as well as the accuracy of estimated parameters. The results have shown that the proposed blind method gives a better estimation of the weak modes from response signals of small signal to noise ratio (SNR)and gives a reliable separation of spurious and physical estimates.
Perú-Chile: imágenes mutuas (Perú-Chile: mutual images
Directory of Open Access Journals (Sweden)
Álvaro González Riesle
2014-06-01
Full Text Available RESUMEN: A partir de los enfoques sobe Expansionismo-Revanchismo de Elizondo y las Imágenes en Espejo de Scott, se analizaron los contenidos de blogs referentes a imágenes mutuas entre Perú y Chile, comprendidos a partir de la fecha (16-01-2008 de presentación por parte del Perú de la Demanda ante el Tribunal de la Haya para la solución del Diferendo Limítrofe con Chile, hasta el 30-03-2011. Se han registrado intensas y variadas manifestaciones de hostilidad mutua, que respaldan la vigencia de la dinámica Expansionismo-Revanchismo en las imágenes mutuas entre Chile y Perú en los blogs analizados. Paralelamente, se detectaron contenidos correspondientes a actitudes integracionistas entre ambos países. Los resultados fundamentan la utilidad del enfoque de las Imágenes en Espejo como instrumento para el análisis de contenido de blogs portadores de mensajes de hostilidad e integración entre ambos países. Se propone una estrategia psicosocial binacional para desactivar la dinámica Expansionismo- revanchismo que contribuiría a producir catastróficas consecuencias para las generaciones actuales y futuras de ambos países; y, promover la integración fronteriza entre Tacna (Perú y Arica (Chile. ABSTRACT: The contents of blogs relating to mutual images between Peru and Chile were analyzed from the approaches about Expansionism – Revanchism of Elizondo, and The images on the mirror of Scott, included the date of the presentation (January 16th, 2008 by Peru of the demand before the International Court of Justice at the Hague for the solution of the border dispute with Chile until March 30th, 2011. There have been intense and varied manifestations of mutual hostility that support the validity of Expansionism-Revanchism dynamics in the mutual images between Chile and Peru in the analyzed blogs. At the same time, it was detected content corresponding to integrationist attitudes between the two countries. The results underlie the utility
Quantification of Covariance in Tropical Cyclone Activity across Teleconnected Basins
Tolwinski-Ward, S. E.; Wang, D.
2015-12-01
Rigorous statistical quantification of natural hazard covariance across regions has important implications for risk management, and is also of fundamental scientific interest. We present a multivariate Bayesian Poisson regression model for inferring the covariance in tropical cyclone (TC) counts across multiple ocean basins and across Saffir-Simpson intensity categories. Such covariability results from the influence of large-scale modes of climate variability on local environments that can alternately suppress or enhance TC genesis and intensification, and our model also simultaneously quantifies the covariance of TC counts with various climatic modes in order to deduce the source of inter-basin TC covariability. The model explicitly treats the time-dependent uncertainty in observed maximum sustained wind data, and hence the nominal intensity category of each TC. Differences in annual TC counts as measured by different agencies are also formally addressed. The probabilistic output of the model can be probed for probabilistic answers to such questions as: - Does the relationship between different categories of TCs differ statistically by basin? - Which climatic predictors have significant relationships with TC activity in each basin? - Are the relationships between counts in different basins conditionally independent given the climatic predictors, or are there other factors at play affecting inter-basin covariability? - How can a portfolio of insured property be optimized across space to minimize risk? Although we present results of our model applied to TCs, the framework is generalizable to covariance estimation between multivariate counts of natural hazards across regions and/or across peril types.
Action recognition from video using feature covariance matrices.
Guo, Kai; Ishwar, Prakash; Konrad, Janusz
2013-06-01
We propose a general framework for fast and accurate recognition of actions in video using empirical covariance matrices of features. A dense set of spatio-temporal feature vectors are computed from video to provide a localized description of the action, and subsequently aggregated in an empirical covariance matrix to compactly represent the action. Two supervised learning methods for action recognition are developed using feature covariance matrices. Common to both methods is the transformation of the classification problem in the closed convex cone of covariance matrices into an equivalent problem in the vector space of symmetric matrices via the matrix logarithm. The first method applies nearest-neighbor classification using a suitable Riemannian metric for covariance matrices. The second method approximates the logarithm of a query covariance matrix by a sparse linear combination of the logarithms of training covariance matrices. The action label is then determined from the sparse coefficients. Both methods achieve state-of-the-art classification performance on several datasets, and are robust to action variability, viewpoint changes, and low object resolution. The proposed framework is conceptually simple and has low storage and computational requirements making it attractive for real-time implementation. PMID:23508265
Structural covariance networks in the mouse brain.
Pagani, Marco; Bifone, Angelo; Gozzi, Alessandro
2016-04-01
The presence of networks of correlation between regional gray matter volume as measured across subjects in a group of individuals has been consistently described in several human studies, an approach termed structural covariance MRI (scMRI). Complementary to prevalent brain mapping modalities like functional and diffusion-weighted imaging, the approach can provide precious insights into the mutual influence of trophic and plastic processes in health and pathological states. To investigate whether analogous scMRI networks are present in lower mammal species amenable to genetic and experimental manipulation such as the laboratory mouse, we employed high resolution morphoanatomical MRI in a large cohort of genetically-homogeneous wild-type mice (C57Bl6/J) and mapped scMRI networks using a seed-based approach. We show that the mouse brain exhibits robust homotopic scMRI networks in both primary and associative cortices, a finding corroborated by independent component analyses of cortical volumes. Subcortical structures also showed highly symmetric inter-hemispheric correlations, with evidence of distributed antero-posterior networks in diencephalic regions of the thalamus and hypothalamus. Hierarchical cluster analysis revealed six identifiable clusters of cortical and sub-cortical regions corresponding to previously described neuroanatomical systems. Our work documents the presence of homotopic cortical and subcortical scMRI networks in the mouse brain, thus supporting the use of this species to investigate the elusive biological and neuroanatomical underpinnings of scMRI network development and its derangement in neuropathological states. The identification of scMRI networks in genetically homogeneous inbred mice is consistent with the emerging view of a key role of environmental factors in shaping these correlational networks.
Covariance evaluation for actinide nuclear data in JENDL-4
International Nuclear Information System (INIS)
Full text: The JENDL-4.0 was released in March 2010. It provides neutron nuclear data for 79 actinides from Ac to Fm. All of the actinides include covariance data. The covariance data were evaluated for reaction cross sections, resonance parameters, angular distributions of elastic scattering, average number of neutrons per fission, and prompt fission neutron spectra. They were deduced basically based on the consistent methodologies with the nuclear data evaluations. Statistical processing of experimental data sometimes gives unacceptably small uncertainty compared with experimental data. They may arise from ignoring unknown errors and correlation of experimental data and also from the modeling errors. The covariance data obtained from statistical estimation using the least-squares method were sometimes modified to be reasonable taking account of consistency with dispersion of experimental data, which may reflect the uncertainties of the data. For the fast neutron fission cross sections of 6 major actinides of 233,235,238U and 239,240,241Pu were evaluated simultaneously using both cross section and their ratio data with the least- squares fitting code SOK. It gave the covariance matrices that have cross correlations between different nuclei included in the analyses. For the minor actinide, the least-squares fitting code GMA was used for fission cross section evaluation for fast neutrons. The covariance data were obtained from the calculations at the same time. For other reaction cross sections, covariance matrices were evaluated using CCONE-KALMAN code system. Sensitivities to model parameters were calculated by CCONE code and used to estimate covariance matrices of the parameters with KALMAN code. Covariance matrices for other data such as resonance parameters and average numbers of fission neutrons were also evaluated based on experimental data. The evaluated covariance data were compiled to the ENDF-6 format files and included in JENDL-4.
Quantifying the taxonomic diversity in real species communities
Cartozo, C Caretta; Ricotta, C; Barthelemy, M; Caldarelli, G
2008-01-01
We analyze several florae (collections of plant species populating specific areas) in different geographic and climatic regions. For every list of species we produce a taxonomic classification tree and we consider its statistical properties. We find that regardless of the geographical location, the climate and the environment all species collections have universal statistical properties that we show to be also robust in time. We then compare observed data sets with simulated communities obtained by randomly sampling a large pool of species from all over the world. We find differences in the behavior of the statistical properties of the corresponding taxonomic trees. Our results suggest that it is possible to distinguish quantitatively real species assemblages from random collections and thus demonstrate the existence of correlations between species.
Chile: Una Vision Politica, Economica y Social (Chile: A Political, Economic, and Social View).
Cortes-Hwang, Adriana
1972-01-01
This address seeks to explain in brief the historical background and political, economic, and social conditions leading to the democratic election of a Marxist president in Chile. A historical sketch of Chilean government from independence in 1810 is provided with a description of the situation just before Salvador Allende's election in 1969. Some…
The Mass Media and Political Socialization: Chile, 1970-2000
Walter, Amy R.
2005-01-01
This project seeks to determine the effect of the mass media on political attitudes and behaviors in Chile between the years 1970 and 2000. The relationship between the media and "political socialization" is just now gaining recognition in scholarly research, and Chile offers an excellent case study. This paper traces these two variables during…
Chile, Latin America, and the Asia-Pacific Region
Directory of Open Access Journals (Sweden)
Manfred Wilhelmy
2005-01-01
Full Text Available Text of a presentation in the Colloquium Chile and the World, organized by the Princeton University Program in Latin American Studies, May 6, 2005, in honor of Professor Paul E.Sigmund. The views expressed have not been reviewed or endorsed by the Chile Pacific Foundation. Manfred Wilhelmy holds a Ph.D. in Politics (1973 from Princeton University
Chile - Institutional Design for an Effective Education Quality Assurance
World Bank
2007-01-01
The main objective of this report is to present the Government of Chile with policy options related to the institutional distribution of roles and responsibilities for effective quality assurance in education. Following the introduction, the report is structured as follows. Chapter II presents background information on the evolution of Chile's education system since 1980. This information,...
Childcare in Chile. The role of ethnicity and socioeconomic inequalities
Cárcamo Leiva, Rodrigo Alejandro
2014-01-01
Chile has embarked on a road that must lead to the reduction of inequality gaps for the population. A public policy called Chile Growths With You has focused on an increase in the breadth of coverage of non-maternal care through childcare centers to provide equal opportunities in early childhood and
Honors in Chile: New Engagements in the Higher Education System
Skewes, Juan Carlos; Sampaio, Carlos Alberto Cioce; Conway, Frederick J.
2012-01-01
Honors programs are rare in Latin America, and in Chile they were unknown before 2003. At the Universidad Austral de Chile, an interdisciplinary group of scholars linked to environmental studies put forward a pilot project for implementing a new experience in higher education. Challenged by an educational environment where (i) apathy and…
Critical Perspectives on Adolescent Vocational Guidance in Chile
McWhirter, Ellen Hawley; McWhirter, Benedict T.
2012-01-01
In this article, the lens of critical psychology is applied to adolescent career development and vocational guidance in Chile. The authors describe and critique the status of adolescent vocational guidance in Chile, the reproduction of extant social inequities in Chilean education, and offer recommendations for enhancing vocational guidance…
Taxonomical and functional microbial community selection in soybean rhizosphere
Lucas W. Mendes; Kuramae, Eiko E.; Navarrete, Acácio A; van Veen, Johannes A.; Tsai, Siu M.
2014-01-01
This study addressed the selection of the rhizospheric microbial community from the bulk soil reservoir under agricultural management of soybean in Amazon forest soils. We used a shotgun metagenomics approach to investigate the taxonomic and functional diversities of microbial communities in the bulk soil and in the rhizosphere of soybean plants and tested the validity of neutral and niche theories to explain the rhizosphere community assembly processes. Our results showed a clear selection a...
Genetic Variation in Nacobbus aberrans: An Approach toward Taxonomic Resolution
Ibrahim, S. K.; Baldwin, J. G.; Roberts, P. A.; Hyman, B.C.
1997-01-01
Biochemical and molecular analyses of genetic variation were evaluated to address the taxonomic status of Nacobbus aberrans. Isolates from Mexico, Peru, and Argentina, cultured on tomato in the greenhouse, were analyzed with respect to isozyme and DNA marker variation. Although acid phosphatase and malate dehydrogenase revealed distinct profiles for each isolate, non-specific esterases revealed possible affinities between the Peruvian isolates and between the isolates from Mexico and Peru. Tw...
Taxonomic Revision and Molecular Studies of Garcinia Section Garcinia (Guttiferae)
Saleh, Mohd. Nazre
2006-01-01
Garcinia section Garcinia is one of 14 sections of the species-rich pantropical genus Garcinia (Guttiferae/Clusiaceae). In its most recent circumscription the section comprised 43 species, mostly of rain forest understorey trees, distributed from eastern India to Fiji, and in Madagascar (Jones, 1980: unpublished Phd. Thesis, University of Leicester). Its most famous member is the fruit tree, mangosteen (G. mangostana). Taxonomic revision of section Garcinia reduces the number o...
A taxonomic revision of the genus Dolianthus (Rubiaceae)
Davis, Aaron P.; Bridson, Diane M.
2001-01-01
A taxonomic revision of Dolianthus C.H. Wright (Rubiaceae-Psychotrieae) is presented, including a key to species, full descriptions, distribution maps, and a list of specimens examined. Eleven species are transferred from Amaracarpus to Dolianthus, resulting in ten new combinations. Two species are described as new to science: D. kairoi and D. ovatifolius. In total, thirteen species are included in Dolianthus. Dolianthus is endemic to the highlands (montane to subalpine and alpine zones) of P...
ComTax: community-driven curation for taxonomic databases
Morse, David; Yang, Hui; Willis,Alistair; De Roeck, Anne; King, David
2013-01-01
This poster presents the work of the ComTax project to develop a community-driven curation process among practicing scientists and citizen scientists. The project provides tools to help scientists identify and validate appropriate taxonomic names from the scanned historical literature. The system operates on scanned documents, typically taken from the Biodiversity Heritage Library, although documents sourced from other repositories could be used. The system is intended to be used on uncor...
Covariance matrices and applications to the field of nuclear data
International Nuclear Information System (INIS)
A student's introduction to covariance error analysis and least-squares evaluation of data is provided. It is shown that the basic formulas used in error propagation can be derived from a consideration of the geometry of curvilinear coordinates. Procedures for deriving covariances for scaler and vector functions of several variables are presented. Proper methods for reporting experimental errors and for deriving covariance matrices from these errors are indicated. The generalized least-squares method for evaluating experimental data is described. Finally, the use of least-squares techniques in data fitting applications is discussed. Specific examples of the various procedures are presented to clarify the concepts
Reality conditions for Ashtekar gravity from Lorentz-covariant formulation
Energy Technology Data Exchange (ETDEWEB)
Alexandrov, Sergei [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, Postbus 80.195, 3508 TD Utrecht (Netherlands)
2006-03-21
We study the limit of the Lorentz-covariant canonical formulation where the Immirzi parameter approaches {beta} = i. We show that, formulated in terms of a shifted spacetime connection, which also plays a crucial role in the covariant quantization, the limit is smooth and reproduces the canonical structure of the self-dual Ashtekar gravity. The reality conditions of Ashtekar gravity can be incorporated by means of the Dirac brackets derived from the covariant formulation and defined on an extended phase space which involves, besides the self-dual variables, also their anti-self-dual counterparts.
Covariance analysis for Energy Density Functionals and instabilities
Roca-Maza, X; Colò, G
2014-01-01
We present the covariance analysis of two successful nuclear energy density functionals, (i) a non-relativistic Skyrme functional built from a zero-range effective interaction, and (ii) a relativistic nuclear energy density functional based on density dependent meson-nucleon couplings. Such a study is crucial for assessing the information content of an observable when predicted by a given model. The covariance analysis is a useful tool for understanding the limitations of a model, the correlations between observables and the statistical errors. We also provide a brief review, partly connected with the covariance analysis, of some instabilities displayed by several energy density functionals of current use in nuclear physics.
Poincaré covariance of relativistic quantum position
Farkas, S; Weiner, M D; Farkas, Sz.
2002-01-01
A great number of problems of relativistic position in quantum mechanics are due to the use of coordinates which are not inherent objects of spacetime, cause unnecessary complications and can lead to misconceptions. We apply a coordinate-free approach to rule out such problems. Thus it will be clear, for example, that the Lorentz covariance of position, required usually on the analogy of Lorentz covariance of spacetime coordinates, is not well posed and we show that in a right setting the Newton--Wigner position is Poincar\\'e covariant, in contradiction with the usual assertions.
Bayes linear covariance matrix adjustment for multivariate dynamic linear models
Wilkinson, Darren J
2008-01-01
A methodology is developed for the adjustment of the covariance matrices underlying a multivariate constant time series dynamic linear model. The covariance matrices are embedded in a distribution-free inner-product space of matrix objects which facilitates such adjustment. This approach helps to make the analysis simple, tractable and robust. To illustrate the methods, a simple model is developed for a time series representing sales of certain brands of a product from a cash-and-carry depot. The covariance structure underlying the model is revised, and the benefits of this revision on first order inferences are then examined.
Estimation of time series noise covariance using correlation technology
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
Covariance of clean signal and observed noise is necessary for extracting clean signal from a time series.This is transferred to calculate the covariance of observed noise and clean signal's MA process,when the clean signal is described by an autoregressive moving average (ARMA) model.Using the correlations of the innovations data from observed time series to form a least-squares problem,a concisely autocovariance least-square (CALS) method has been proposed to estimate the covariance.We also extended our w...
Estimating Complex Covariance by Observing Two Variables at a Time
Institute of Scientific and Technical Information of China (English)
C. S. WITHERS; S. NADARAJAH; O. N(Φ)RKLI; R. RAICH; R.G. VAUGHAN
2012-01-01
The estimation of covariance matrices is central in array signal processing systems.This note addresses complex covariance estimation for the situation,where the complex data are available only as independent pairwise sets (observations) corresponding to individual elements of the matrix.The formulation for the empirical estimate and the normal maximum likelihood estimate is developed for the general case of different sample sizes for each observation.The approach allows,for example,the estimate of the p by p covariance matrix of a p-port sensor array from a two-port measurement instrument.
Condensed matter many-body theory in relativistic covariant form
Olevano, Valerio; Ladisa, Massimo
2010-01-01
We present a relativistic covariant form of many-body theory. The many-body covariant Lagrangian is derived from QED by integrating out the internal non-quantized electromagnetic field. The ordinary many-body Hamiltonian is recovered as an approximation to the exact covariant theory that contains many-body terms beyond the solely electrostatic interaction, e.g. the Lorentz force among electrons, spin-spin etc. Spin and relativistic terms, e.g. spin-orbit, are also automatically accounted. Mor...
Directory of Open Access Journals (Sweden)
Frassinetti, D.
2000-12-01
Full Text Available Fossil remains belonging to Equidae fram Chilean localities are described and taxonomically determined. Equus (Amerhippus and Hippidion species are identified; its geographic distribution in Chile and relations with others South American Equidae are given; a Late Pleistocene age is regarded for them. Stratigraphic and paleoecological considerations are also included.Se describen y sitúan taxonómicamente los restos de équidos de las localidades chilenas. Se identifican distintas especies de Equus (Amerhippus e Hippidion, señalando su distribución geográfica y relaciones con otros équidos sudamericanos, además de referirlos al Pleistoceno superior. Se analiza su situación estratigráfica así como consideraciones de tipo paleoecológico.
Taxonomical and functional microbial community selection in soybean rhizosphere.
Mendes, Lucas W; Kuramae, Eiko E; Navarrete, Acácio A; van Veen, Johannes A; Tsai, Siu M
2014-08-01
This study addressed the selection of the rhizospheric microbial community from the bulk soil reservoir under agricultural management of soybean in Amazon forest soils. We used a shotgun metagenomics approach to investigate the taxonomic and functional diversities of microbial communities in the bulk soil and in the rhizosphere of soybean plants and tested the validity of neutral and niche theories to explain the rhizosphere community assembly processes. Our results showed a clear selection at both taxonomic and functional levels operating in the assembly of the soybean rhizosphere community. The taxonomic analysis revealed that the rhizosphere community is a subset of the bulk soil community. Species abundance in rhizosphere fits the log-normal distribution model, which is an indicator of the occurrence of niche-based processes. In addition, the data indicate that the rhizosphere community is selected based on functional cores related to the metabolisms of nitrogen, iron, phosphorus and potassium, which are related to benefits to the plant, such as growth promotion and nutrition. The network analysis including bacterial groups and functions was less complex in rhizosphere, suggesting the specialization of some specific metabolic pathways. We conclude that the assembly of the microbial community in the rhizosphere is based on niche-based processes as a result of the selection power of the plant and other environmental factors. PMID:24553468
Covariance of metabolic and hemostatic risk indicators in men and women
Riese, H; Vrijkotte, TGM; Meijer, P; Kluft, C; De Geus, EJC
2001-01-01
Background and objective: Multivariate analyses on clusters of metabolic and hemostatic risk indicators implicitly assume good test-retest reliability of these variables, substantial covariance among the various indicators, stability of covariance structure over time, and comparable covariance struc
China and Chile Are to Be Free-Trade Partners
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
@@ In line with the words "We hope that Chile's Next Partner is China", Chile is believed to choose China as the new negotiation party of Free Trade Agreements after signing respectively free trade agreements with Canada, the United States, EU and ROK. On January 24, Chile's trade delegation composed of 20 members led by Kaiross Feirch, the Head of economy general department of the Ministry of Foreign Affairs paid the first visit to China to launch first five-day round of mutual trade negotiation.Kaiross Feirch, the Head of economy general department of the Ministry of Foreign Affairs of Chile and Barbirlo Kafuleirla, Chile's Ambassador to China received special visit of reporters about this round.
Sanchez, Juan A; Reddy, Vishnu; Nathues, Andreas
2013-01-01
In the past, constraining the surface composition of near-Earth asteroids (NEAs) has been difficult due to the lack of high quality near-IR spectral data (0.7-2.5 microns) that contain mineralogically diagnostic absorption bands. Here we present visible (0.43-0.95 microns) and near-infrared (0.7-2.5 microns) spectra of nine NEAs and five Mars-crossing asteroids (MCs). The studied NEAs are: 4055 Magellan, 19764 (2000 NF5), 89830 (2002 CE), 138404 (2000 HA24), 143381 (2003 BC21), 159609 (2002 AQ3), 164121 (2003 YT1), 241662 (2000 KO44) and 2007 ML13. The studied MCs are: 1656 Suomi, 2577 Litva, 5407 (1992 AX), 22449 Ottijeff and 47035 (1998 WS). The observations were conducted with the NTT at La Silla, Chile, the 2.2 m telescope at Calar Alto, Spain, and the IRTF on Mauna Kea, Hawai'i. The taxonomic classification (Bus system) of asteroids showed that all observed MC asteroids belong to the S-complex, including the S, Sr and Sl classes. Seven of the NEAs belong to the S-complex, including the S, Sa, Sk and Sl c...
Directory of Open Access Journals (Sweden)
Pablo A Oyarzún
2014-03-01
Full Text Available The sperm ultrastructure has been used to solve several systematic and phylogenetic problems in marine invertebrates. The sperm ultrastructure of the Chilean mussel Mytilus chilensis and Mytilus galloprovincialis corresponds to the ect-aquasperm type. Sperm from both taxa measured 55-60 μm between head (acrosome + nucleus, midpiece (only 5 mitochondria and the flagellum which in its end piece has a smaller diameter tail. The differences between both taxa are clearly shown, in the structure of the acrosome and nucleus. Therefore, according to our results and those reported in the literature, we indicate that Chilean native mussel sperm is different from other species of the Mytilus complex (M. trossulus, M. galloprovincialis and M. edulis. These differences in sperm ultrastructure found in M. chilensis, are another trait that can be used to validate the taxonomic status of the species. Differences in sperm morphology are related with reproductive isolation, and probably will be useful to understand future data on speciation. Finally, we discussed the finding that Mytilus galloprovincialis sperm from Chile have an acrosome notoriously smaller than those reported for specimens from Europe and Africa, though they have a great similarity with specimens from Japan, as reported in the literature.
Marine Biodiversity in Juan Fernández and Desventuradas Islands, Chile: Global Endemism Hotspots
Friedlander, Alan M.; Ballesteros, Enric; Caselle, Jennifer E.; Gaymer, Carlos F.; Palma, Alvaro T.; Petit, Ignacio; Varas, Eduardo; Muñoz Wilson, Alex; Sala, Enric
2016-01-01
The Juan Fernández and Desventuradas islands are among the few oceanic islands belonging to Chile. They possess a unique mix of tropical, subtropical, and temperate marine species, and although close to continental South America, elements of the biota have greater affinities with the central and south Pacific owing to the Humboldt Current, which creates a strong biogeographic barrier between these islands and the continent. The Juan Fernández Archipelago has ~700 people, with the major industry being the fishery for the endemic lobster, Jasus frontalis. The Desventuradas Islands are uninhabited except for a small Chilean military garrison on San Félix Island. We compared the marine biodiversity of these islands across multiple taxonomic groups. At San Ambrosio Island (SA), in Desventuradas, the laminarian kelp (Eisenia cokeri), which is limited to Desventuradas in Chile, accounted for >50% of the benthic cover at wave exposed areas, while more sheltered sites were dominated by sea urchin barrens. The benthos at Robinson Crusoe Island (RC), in the Juan Fernández Archipelago, comprised a diverse mix of macroalgae and invertebrates, a number of which are endemic to the region. The biomass of commercially targeted fishes was >2 times higher in remote sites around RC compared to sheltered locations closest to port, and overall biomass was 35% higher around SA compared to RC, likely reflecting fishing effects around RC. The number of endemic fish species was extremely high at both islands, with 87.5% of the species surveyed at RC and 72% at SA consisting of regional endemics. Remarkably, endemics accounted for 99% of the numerical abundance of fishes surveyed at RC and 96% at SA, which is the highest assemblage-level endemism known for any individual marine ecosystem on earth. Our results highlight the uniqueness and global significance of these biodiversity hotspots exposed to very different fishing pressures. PMID:26734732
Marine Biodiversity in Juan Fernandez and Desventuradas Islands, Chile: Global Endemism Hotspots.
Directory of Open Access Journals (Sweden)
Alan M Friedlander
Full Text Available The Juan Fernández and Desventuradas islands are among the few oceanic islands belonging to Chile. They possess a unique mix of tropical, subtropical, and temperate marine species, and although close to continental South America, elements of the biota have greater affinities with the central and south Pacific owing to the Humboldt Current, which creates a strong biogeographic barrier between these islands and the continent. The Juan Fernández Archipelago has ~700 people, with the major industry being the fishery for the endemic lobster, Jasus frontalis. The Desventuradas Islands are uninhabited except for a small Chilean military garrison on San Félix Island. We compared the marine biodiversity of these islands across multiple taxonomic groups. At San Ambrosio Island (SA, in Desventuradas, the laminarian kelp (Eisenia cokeri, which is limited to Desventuradas in Chile, accounted for >50% of the benthic cover at wave exposed areas, while more sheltered sites were dominated by sea urchin barrens. The benthos at Robinson Crusoe Island (RC, in the Juan Fernández Archipelago, comprised a diverse mix of macroalgae and invertebrates, a number of which are endemic to the region. The biomass of commercially targeted fishes was >2 times higher in remote sites around RC compared to sheltered locations closest to port, and overall biomass was 35% higher around SA compared to RC, likely reflecting fishing effects around RC. The number of endemic fish species was extremely high at both islands, with 87.5% of the species surveyed at RC and 72% at SA consisting of regional endemics. Remarkably, endemics accounted for 99% of the numerical abundance of fishes surveyed at RC and 96% at SA, which is the highest assemblage-level endemism known for any individual marine ecosystem on earth. Our results highlight the uniqueness and global significance of these biodiversity hotspots exposed to very different fishing pressures.
Marine Biodiversity in Juan Fernández and Desventuradas Islands, Chile: Global Endemism Hotspots.
Friedlander, Alan M; Ballesteros, Enric; Caselle, Jennifer E; Gaymer, Carlos F; Palma, Alvaro T; Petit, Ignacio; Varas, Eduardo; Muñoz Wilson, Alex; Sala, Enric
2016-01-01
The Juan Fernández and Desventuradas islands are among the few oceanic islands belonging to Chile. They possess a unique mix of tropical, subtropical, and temperate marine species, and although close to continental South America, elements of the biota have greater affinities with the central and south Pacific owing to the Humboldt Current, which creates a strong biogeographic barrier between these islands and the continent. The Juan Fernández Archipelago has ~700 people, with the major industry being the fishery for the endemic lobster, Jasus frontalis. The Desventuradas Islands are uninhabited except for a small Chilean military garrison on San Félix Island. We compared the marine biodiversity of these islands across multiple taxonomic groups. At San Ambrosio Island (SA), in Desventuradas, the laminarian kelp (Eisenia cokeri), which is limited to Desventuradas in Chile, accounted for >50% of the benthic cover at wave exposed areas, while more sheltered sites were dominated by sea urchin barrens. The benthos at Robinson Crusoe Island (RC), in the Juan Fernández Archipelago, comprised a diverse mix of macroalgae and invertebrates, a number of which are endemic to the region. The biomass of commercially targeted fishes was >2 times higher in remote sites around RC compared to sheltered locations closest to port, and overall biomass was 35% higher around SA compared to RC, likely reflecting fishing effects around RC. The number of endemic fish species was extremely high at both islands, with 87.5% of the species surveyed at RC and 72% at SA consisting of regional endemics. Remarkably, endemics accounted for 99% of the numerical abundance of fishes surveyed at RC and 96% at SA, which is the highest assemblage-level endemism known for any individual marine ecosystem on earth. Our results highlight the uniqueness and global significance of these biodiversity hotspots exposed to very different fishing pressures.
Chile's pension reform after twenty years
Acuna R., Rodrigo; Iglesias P., Augusto
2001-01-01
The aim of this paper is to describe the 1980 Chilean pension reform and to present its main results and economic impact. It is mainly descriptive; however we have tried to emphasize the lessons that may be learned and that may be of interest to other countries in different circumstances. In particular, we focus on potential areas for regulatory improvements. In Section II, a brief description of the AFP system and its place within Chile's social security system is presented. Also, the main c...
Financiamiento de la vivienda en Chile
Morandé, Felipe G.; Garcia, Carlos
2004-01-01
El financiamiento a la vivienda en Chile ha alcanzado en los últimos 20 años un grado de desarrollo muy importante. Para esto ha sido fundamental: a) la eliminación del efecto de la inflación sobre el valor de las deudas de largo plazo, primero, mediante el desarrollo de una unidad de cuenta indexada a la inflación creíble y transparente (la UF), y posteriormente, con el abatimiento de la inflación como fenómeno macroeconómico; b) la reforma provisional de comienzos de los años 80, que fue cl...
Chile Successfully Halts Rise in Childhood Obesity
International Nuclear Information System (INIS)
The increasing prevalence of childhood obesity in Latin America has become a cause for concern. The IAEA has worked closely with the Institute of Nutrition and Food Technology (INTA) at the University of Chile since 1997 to address the problem of malnutrition in the country. In Santiago, the Laboratory of Energy Metabolism and Stable Isotopes was established in 1998 with the help of the IAEA to provide an isotope ratio mass spectrometer and training in the use of stable isotope techniques to assess body composition, infant feeding practices and total daily energy expenditure
Filp, Johanna; Undurrage, Consuelo
This paper examines the current status of programs for preschool children in Chile. Section 1 of the paper provides an overview of the situation of preschool children in Chile. The country's population includes more than 1.6 million children between the ages of 0 and 5 years 11 months, and in urban areas, 18.4 percent of children between the ages…
AFCI-2.0 Neutron Cross Section Covariance Library
Energy Technology Data Exchange (ETDEWEB)
Herman, M.; Herman, M; Oblozinsky, P.; Mattoon, C.M.; Pigni, M.; Hoblit, S.; Mughabghab, S.F.; Sonzogni, A.; Talou, P.; Chadwick, M.B.; Hale, G.M.; Kahler, A.C.; Kawano, T.; Little, R.C.; Yount, P.G.
2011-03-01
The cross section covariance library has been under development by BNL-LANL collaborative effort over the last three years. The project builds on two covariance libraries developed earlier, with considerable input from BNL and LANL. In 2006, international effort under WPEC Subgroup 26 produced BOLNA covariance library by putting together data, often preliminary, from various sources for most important materials for nuclear reactor technology. This was followed in 2007 by collaborative effort of four US national laboratories to produce covariances, often of modest quality - hence the name low-fidelity, for virtually complete set of materials included in ENDF/B-VII.0. The present project is focusing on covariances of 4-5 major reaction channels for 110 materials of importance for power reactors. The work started under Global Nuclear Energy Partnership (GNEP) in 2008, which changed to Advanced Fuel Cycle Initiative (AFCI) in 2009. With the 2011 release the name has changed to the Covariance Multigroup Matrix for Advanced Reactor Applications (COMMARA) version 2.0. The primary purpose of the library is to provide covariances for AFCI data adjustment project, which is focusing on the needs of fast advanced burner reactors. Responsibility of BNL was defined as developing covariances for structural materials and fission products, management of the library and coordination of the work; LANL responsibility was defined as covariances for light nuclei and actinides. The COMMARA-2.0 covariance library has been developed by BNL-LANL collaboration for Advanced Fuel Cycle Initiative applications over the period of three years, 2008-2010. It contains covariances for 110 materials relevant to fast reactor R&D. The library is to be used together with the ENDF/B-VII.0 central values of the latest official release of US files of evaluated neutron cross sections. COMMARA-2.0 library contains neutron cross section covariances for 12 light nuclei (coolants and moderators), 78 structural
Problems with Pencils: Lensing Covariance of Supernova Distance Measurements
Cooray, A R; Holz, D; Cooray, Asantha; Huterer, Dragan; Categories, Daniel Holz
2006-01-01
While luminosity distances from Type Ia supernovae (SNe) provide a powerful probe of cosmological parameters, the accuracy with which these distances can be measured is limited by cosmic magnification due to gravitational lensing by the intervening large-scale structure. Spatial clustering of foreground mass fluctuations leads to correlated errors in distance estimates from SNe. By including the full covariance matrix of supernova distance measurements, we show that a future survey covering more than a few square degrees on the sky, and assuming a total of ~2000 SNe, will be largely unaffected by covariance noise. ``Pencil beam'' surveys with small fields of view, however, will be prone to the lensing covariance, leading to potentially significant degradations in cosmological parameter estimates. For a survey with 30 arcmin mean separation between SNe, lensing covariance leads to a ~45% increase in the expected errors in dark energy parameters compared to fully neglecting lensing, and a ~20% increase compared...
Measuring covariation in RNA alignments: Physical realism improves information measures
DEFF Research Database (Denmark)
Lindgreen, Stinus; Gardner, Paul Phillip; Krogh, Anders
2006-01-01
part of such an analysis is to measure covariation between two positions in an alignment. Here, we rank various measures ranging from simple mutual information to more advanced covariation measures. Results: Mutual information is still used for secondary structure prediction, but the results...... of this study indicate which measures are useful. Incorporating more structural information by considering e.g. indels and stacking improves accuracy, suggesting that physically realistic measures yield improved predictions. This can be used to improve both current and future programs for secondary structure...... prediction. The best measure tested is the RNAalifold covariation measure modified to include stacking. Availability: Scripts, data and supplementary material can be found at http://www.binf.ku.dk/Stinus_covariation Contact: stinus@binf.ku.dk Supplementary information: Supplementary data are available...
Graphical representation of covariant-contravariant modal formulae
Aceto, Luca; de Frutos-Escrig, David; Ingólfsdóttir, Anna; Palomino, Miguel; 10.4204/EPTCS.64.1
2011-01-01
Covariant-contravariant simulation is a combination of standard (covariant) simulation, its contravariant counterpart and bisimulation. We have previously studied its logical characterization by means of the covariant-contravariant modal logic. Moreover, we have investigated the relationships between this model and that of modal transition systems, where two kinds of transitions (the so-called may and must transitions) were combined in order to obtain a simple framework to express a notion of refinement over state-transition models. In a classic paper, Boudol and Larsen established a precise connection between the graphical approach, by means of modal transition systems, and the logical approach, based on Hennessy-Milner logic without negation, to system specification. They obtained a (graphical) representation theorem proving that a formula can be represented by a term if, and only if, it is consistent and prime. We show in this paper that the formulae from the covariant-contravariant modal logic that admit ...
Representation of Gaussian semimartingales with applications to the covariance function
DEFF Research Database (Denmark)
Basse-O'Connor, Andreas
2010-01-01
stationary Gaussian semimartingales and their canonical decomposition. Thirdly, we give a new characterization of the covariance function of Gaussian semimartingales, which enable us to characterize the class of martingales and the processes of bounded variation among the Gaussian semimartingales. We...
Electron localization functions and local measures of the covariance
Indian Academy of Sciences (India)
Paul W Ayers
2005-09-01
The electron localization measure proposed by Becke and Edgecombe is shown to be related to the covariance of the electron pair distribution. Just as with the electron localization function, the local covariance does not seem to be, in and of itself, a useful quantity for elucidating shell structure. A function of the local covariance, however, is useful for this purpose. A different function, based on the hyperbolic tangent, is proposed to elucidate the shell structure encapsulated by the local covariance; this function also seems to work better for the electron localization measure of Becke and Edgecombe. In addition, we propose a different measure for the electron localization that incorporates both the electron localization measure of Becke and Edgecombe and the Laplacian of the electron density; preliminary indications are that this measure is especially good at elucidating the shell structure in valence regions. Methods for evaluating electron localization functions directly from the electron density, without recourse to the Kohn-Sham orbitals, are discussed.
Progress of Covariance Evaluation at the China Nuclear Data Center
International Nuclear Information System (INIS)
Covariance evaluations at the China Nuclear Data Center focus on the cross sections of structural materials and actinides in the fast neutron energy range. In addition to the well-known Least-squares approach, a method based on the analysis of the sources of experimental uncertainties is especially introduced to generate a covariance matrix for a particular reaction for which multiple measurements are available. The scheme of the covariance evaluation flow is presented, and an example of n+90Zr is given to illuminate the whole procedure. It is proven that the accuracy of measurements can be properly incorporated into the covariance and the long-standing small uncertainty problem can be avoided
Lorentz Covariant Canonical Symplectic Algorithms for Dynamics of Charged Particles
Wang, Yulei; Qin, Hong
2016-01-01
In this paper, the Lorentz covariance of algorithms is introduced. Under Lorentz transformation, both the form and performance of a Lorentz covariant algorithm are invariant. To acquire the advantages of symplectic algorithms and Lorentz covariance, a general procedure for constructing Lorentz covariant canonical symplectic algorithms (LCCSA) is provided, based on which an explicit LCCSA for dynamics of relativistic charged particles is built. LCCSA possesses Lorentz invariance as well as long-term numerical accuracy and stability, due to the preservation of discrete symplectic structure and Lorentz symmetry of the system. For situations with time-dependent electromagnetic fields, which is difficult to handle in traditional construction procedures of symplectic algorithms, LCCSA provides a perfect explicit canonical symplectic solution by implementing the discretization in 4-spacetime. We also show that LCCSA has built-in energy-based adaptive time steps, which can optimize the computation performance when th...
Trouble shooting for covariance fitting in highly correlated data
Yoon, Boram; Lee, Weonjong; Jung, Chulwoo
2011-01-01
We report a possible solution to the trouble that the covariance fitting fails when the data is highly correlated and the covariance matrix has small eigenvalues. As an example, we choose the data analysis of highly correlated $B_K$ data on the basis of the SU(2) staggered chiral perturbation theory. Basically, the essence of the problem is that we do not have an accurate fitting function so that we cannot fit the highly correlated and precise data. When some eigenvalues of the covariance matrix are small, even a tiny error of fitting function can produce large chi-square and spoil the fitting procedure. We have applied a number of prescriptions available in the market such as diagonal approximation and cutoff method. In addition, we present a new method, the eigenmode shift method which fine-tunes the fitting function while keeping the covariance matrix untouched.
Covariance fitting of highly correlated $B_K$ data
Yoon, Boram; Jung, Chulwoo; Lee, Weonjong
2011-01-01
We present the reason why we use the diagonal approximation (uncorrelated fitting) when we perform the data analysis of highly correlated $B_K$ data on the basis of the SU(2) staggered chiral perturbation theory. Basically, the essence of the problem is that we do not have enough statistics to determine the small eigenvalues of the covariance matrix with a high precision. As a result, we have the smallest eigenvalue, which is smaller than the statistical error of the covariance matrix, corresponding to an unphysical eigenmode. We have applied a number of prescriptions available in the market such as the cutoff method and modified covariance matrix method. It turns out that the cutoff method is not a good prescription and the modified covariance matrix method is an even worse one. The diagonal approximation turns out to be a good prescription if the data points are somehow correlated and the statistics are relatively poor.
The bispectrum covariance beyond Gaussianity: A log-normal approach
Martin, Sandra; Simon, Patrick
2011-01-01
To investigate and specify the statistical properties of cosmological fields with particular attention to possible non-Gaussian features, accurate formulae for the bispectrum and the bispectrum covariance are required. The bispectrum is the lowest-order statistic providing an estimate for non-Gaussianities of a distribution, and the bispectrum covariance depicts the errors of the bispectrum measurement and their correlation on different scales. Currently, there do exist fitting formulae for the bispectrum and an analytical expression for the bispectrum covariance, but the former is not very accurate and the latter contains several intricate terms and only one of them can be readily evaluated from the power spectrum of the studied field. Neglecting all higher-order terms results in the Gaussian approximation of the bispectrum covariance. We study the range of validity of this Gaussian approximation for two-dimensional non-Gaussian random fields. For this purpose, we simulate Gaussian and non-Gaussian random fi...
75 FR 10846 - The Chile Fund, Inc., et al.; Notice of Application
2010-03-09
... COMMISSION The Chile Fund, Inc., et al.; Notice of Application March 2, 2010. AGENCY: Securities and Exchange.... Applicants: The Chile Fund, Inc. (``Chile Fund''), Aberdeen Australia Equity Fund (``Australia Fund,'' together with the Chile Fund, the ``Current Funds''), Aberdeen Asset Management Asia Limited...
Covariance matrices for track fitting with the Kalman filter
International Nuclear Information System (INIS)
We present a simple and intuitive derivation of the track parameter covariance matrix due to multiple Coulomb scattering for use in track fitting with the Kalman filter. We derive all the covariance matrix elements for two experimentally relevant track parameterizations (i.e. x and y slopes and intercepts, and direction cosines and intercepts) in the presence of thin scatterers and absence of magnetic fields. We further comment on how to account for thick and/or continuous scattering centers. (orig.)
Bayesian parsimonious covariance estimation for hierarchical linear mixed models
Frühwirth-Schnatter, Sylvia; Tüchler, Regina
2004-01-01
We considered a non-centered parameterization of the standard random-effects model, which is based on the Cholesky decomposition of the variance-covariance matrix. The regression type structure of the non-centered parameterization allows to choose a simple, conditionally conjugate normal prior on the Cholesky factor. Based on the non-centered parameterization, we search for a parsimonious variance-covariance matrix by identifying the non-zero elements of the Cholesky factors using Bayesian va...
Web Tool for Constructing a Covariance Matrix from EXFOR Uncertainties
Directory of Open Access Journals (Sweden)
Zerkin V.
2012-05-01
Full Text Available The experimental nuclear reaction database EXFOR contains almost no covariance data because most experimentalists provide experimental data only with uncertainties. With the tool described here a user can construct an experimental covariance matrix from uncertainties using general assumptions when uncertainty information given in EXFOR is poor (or even absent. The tool is publically available in the IAEA EXFOR Web retrieval system [1].
First-order methods for sparse covariance selection
d'Aspremont, Alexandre; Banerjee, Onureena; Ghaoui, Laurent El
2006-01-01
Given a sample covariance matrix, we solve a maximum likelihood problem penalized by the number of nonzero coefficients in the inverse covariance matrix. Our objective is to find a sparse representation of the sample data and to highlight conditional independence relationships between the sample variables. We first formulate a convex relaxation of this combinatorial problem, we then detail two efficient first-order algorithms with low memory requirements to solve large-scale, dense problem in...
Imaging structural co-variance between human brain regions
Alexander-Bloch, Aaron; Giedd, Jay N.; Bullmore, Ed
2013-01-01
Brain structure varies between people in a markedly organized fashion. Communities of brain regions co-vary in their morphological properties. For example, cortical thickness in one region influences the thickness of structurally and functionally connected regions. Such networks of structural co-variance partially recapitulate the functional networks of healthy individuals and the foci of grey matter loss in neurodegenerative disease. This architecture is genetically heritable, is associated ...
Optimal Phase-Covariant Cloning in 3 Dimensions
Institute of Scientific and Technical Information of China (English)
张文海; 余龙宝; 曹卓良; 叶柳
2012-01-01
In this paper, we present the explicit transformations of the optimal 1 → 3, 4, 5 phase-covariant cloning in 3 dimensions. The cloning fidelities are covered by the theoretical bounds of the optimal 1 → 3k, 3k ＋ 1, 3k ＋ 2 phase-covariant cloning of qutrits, where k ≥ 1 is the integral [Phys. Rev. A 67 （2003） 042306].
A Generalized Autocovariance Least-Squares Method for Covariance Estimation
DEFF Research Database (Denmark)
Åkesson, Bernt Magnus; Jørgensen, John Bagterp; Poulsen, Niels Kjølstad;
2007-01-01
A generalization of the autocovariance least- squares method for estimating noise covariances is presented. The method can estimate mutually correlated system and sensor noise and can be used with both the predicting and the filtering form of the Kalman filter.......A generalization of the autocovariance least- squares method for estimating noise covariances is presented. The method can estimate mutually correlated system and sensor noise and can be used with both the predicting and the filtering form of the Kalman filter....
High-dimensional covariance matrix estimation with missing observations
Lounici, Karim
2014-01-01
In this paper, we study the problem of high-dimensional covariance matrix estimation with missing observations. We propose a simple procedure computationally tractable in high-dimension and that does not require imputation of the missing data. We establish non-asymptotic sparsity oracle inequalities for the estimation of the covariance matrix involving the Frobenius and the spectral norms which are valid for any setting of the sample size, probability of a missing observation and the dimensio...
Vargas Fernández, Luis
2002-12-01
When Revista Médica de Chile turns to be 130 years old, the author reflects about the difficulties that scientific and technological creativity faces in Chile, considering that there was a 70 years gap between its historical origin in Chile compared to developed countries. The scientific progress erases the boundaries between Biomedicine and science and technology. This progress has resulted in an improvement in the quality of scientific publications in Revista Medica de Chile. The editorial work has also contributed to this improvement. Revista Medica de Chile has obtained international recognition and stands in a good position as a medical journal in Latin America and Chile.
The Performance Analysis Based on SAR Sample Covariance Matrix
Directory of Open Access Journals (Sweden)
Esra Erten
2012-03-01
Full Text Available Multi-channel systems appear in several fields of application in science. In the Synthetic Aperture Radar (SAR context, multi-channel systems may refer to different domains, as multi-polarization, multi-interferometric or multi-temporal data, or even a combination of them. Due to the inherent speckle phenomenon present in SAR images, the statistical description of the data is almost mandatory for its utilization. The complex images acquired over natural media present in general zero-mean circular Gaussian characteristics. In this case, second order statistics as the multi-channel covariance matrix fully describe the data. For practical situations however, the covariance matrix has to be estimated using a limited number of samples, and this sample covariance matrix follow the complex Wishart distribution. In this context, the eigendecomposition of the multi-channel covariance matrix has been shown in different areas of high relevance regarding the physical properties of the imaged scene. Specifically, the maximum eigenvalue of the covariance matrix has been frequently used in different applications as target or change detection, estimation of the dominant scattering mechanism in polarimetric data, moving target indication, etc. In this paper, the statistical behavior of the maximum eigenvalue derived from the eigendecomposition of the sample multi-channel covariance matrix in terms of multi-channel SAR images is simplified for SAR community. Validation is performed against simulated data and examples of estimation and detection problems using the analytical expressions are as well given.
Gaussian covariance matrices for anisotropic galaxy clustering measurements
Grieb, Jan Niklas; Sánchez, Ariel G.; Salazar-Albornoz, Salvador; Dalla Vecchia, Claudio
2016-04-01
Measurements of the redshift-space galaxy clustering have been a prolific source of cosmological information in recent years. Accurate covariance estimates are an essential step for the validation of galaxy clustering models of the redshift-space two-point statistics. Usually, only a limited set of accurate N-body simulations is available. Thus, assessing the data covariance is not possible or only leads to a noisy estimate. Further, relying on simulated realizations of the survey data means that tests of the cosmology dependence of the covariance are expensive. With these points in mind, this work presents a simple theoretical model for the linear covariance of anisotropic galaxy clustering observations with synthetic catalogues. Considering the Legendre moments (`multipoles') of the two-point statistics and projections into wide bins of the line-of-sight parameter (`clustering wedges'), we describe the modelling of the covariance for these anisotropic clustering measurements for galaxy samples with a trivial geometry in the case of a Gaussian approximation of the clustering likelihood. As main result of this paper, we give the explicit formulae for Fourier and configuration space covariance matrices. To validate our model, we create synthetic halo occupation distribution galaxy catalogues by populating the haloes of an ensemble of large-volume N-body simulations. Using linear and non-linear input power spectra, we find very good agreement between the model predictions and the measurements on the synthetic catalogues in the quasi-linear regime.
Perturbative approach to covariance matrix of the matter power spectrum
Mohammed, Irshad; Vlah, Zvonimir
2016-01-01
We evaluate the covariance matrix of the matter power spectrum using perturbation theory up to dominant terms at 1-loop order and compare it to numerical simulations. We decompose the covariance matrix into the disconnected (Gaussian) part, trispectrum from the modes outside the survey (beat coupling or super-sample variance), and trispectrum from the modes inside the survey, and show how the different components contribute to the overall covariance matrix. We find the agreement with the simulations is at a 10\\% level up to $k \\sim 1 h {\\rm Mpc^{-1}}$. We show that all the connected components are dominated by the large-scale modes ($k<0.1 h {\\rm Mpc^{-1}}$), regardless of the value of the wavevectors $k,\\, k'$ of the covariance matrix, suggesting that one must be careful in applying the jackknife or bootstrap methods to the covariance matrix. We perform an eigenmode decomposition of the connected part of the covariance matrix, showing that at higher $k$ it is dominated by a single eigenmode. The full cova...
A three domain covariance framework for EEG/MEG data.
Roś, Beata P; Bijma, Fetsje; de Gunst, Mathisca C M; de Munck, Jan C
2015-10-01
In this paper we introduce a covariance framework for the analysis of single subject EEG and MEG data that takes into account observed temporal stationarity on small time scales and trial-to-trial variations. We formulate a model for the covariance matrix, which is a Kronecker product of three components that correspond to space, time and epochs/trials, and consider maximum likelihood estimation of the unknown parameter values. An iterative algorithm that finds approximations of the maximum likelihood estimates is proposed. Our covariance model is applicable in a variety of cases where spontaneous EEG or MEG acts as source of noise and realistic noise covariance estimates are needed, such as in evoked activity studies, or where the properties of spontaneous EEG or MEG are themselves the topic of interest, like in combined EEG-fMRI experiments in which the correlation between EEG and fMRI signals is investigated. We use a simulation study to assess the performance of the estimator and investigate the influence of different assumptions about the covariance factors on the estimated covariance matrix and on its components. We apply our method to real EEG and MEG data sets.
Covariance fitting of highly-correlated data in lattice QCD
Yoon, Boram; Jang, Yong-Chull; Jung, Chulwoo; Lee, Weonjong
2013-07-01
We address a frequently-asked question on the covariance fitting of highly-correlated data such as our B K data based on the SU(2) staggered chiral perturbation theory. Basically, the essence of the problem is that we do not have a fitting function accurate enough to fit extremely precise data. When eigenvalues of the covariance matrix are small, even a tiny error in the fitting function yields a large chi-square value and spoils the fitting procedure. We have applied a number of prescriptions available in the market, such as the cut-off method, modified covariance matrix method, and Bayesian method. We also propose a brand new method, the eigenmode shift (ES) method, which allows a full covariance fitting without modifying the covariance matrix at all. We provide a pedagogical example of data analysis in which the cut-off method manifestly fails in fitting, but the rest work well. In our case of the B K fitting, the diagonal approximation, the cut-off method, the ES method, and the Bayesian method work reasonably well in an engineering sense. However, interpreting the meaning of χ 2 is easier in the case of the ES method and the Bayesian method in a theoretical sense aesthetically. Hence, the ES method can be a useful alternative optional tool to check the systematic error caused by the covariance fitting procedure.
Tania Dehesh; Najaf Zare; Seyyed Mohammad Taghi Ayatollahi
2015-01-01
Background. Univariate meta-analysis (UM) procedure, as a technique that provides a single overall result, has become increasingly popular. Neglecting the existence of other concomitant covariates in the models leads to loss of treatment efficiency. Our aim was proposing four new approximation approaches for the covariance matrix of the coefficients, which is not readily available for the multivariate generalized least square (MGLS) method as a multivariate meta-analysis approach. Me...
Directory of Open Access Journals (Sweden)
J Retamales
2011-01-01
Full Text Available Insects are common in poultry facilities and different biosecurity measures are enforced to prevent their spread due to the fact that they may carry pathogenic agents. Therefore, it is of utmost importance to know what insects are commonly present in poultry sheds to optimize control protocols. Since information on this subject is scarce, this investigation aimed to determine the main insect taxa present in chicken manure on a major poultry farm in Central Chile. Samples of hen manure were collected at a poultry farm in the Region of Valparaíso, Chile, from areas adjacent to feeding lines and water reservoirs. Samples were chilled, transported to the laboratory and processed for taxonomic classification of both adult and immature stages of insects. Results indicated a marked colonization of the beetle Alphitobius diaperinus and of the dipterans Fannia sp., compared to other six families of insects that were also determined. About 94% of the insects found in chicken manure were present in samples from areas adjacent to water reservoirs. Therefore, leaks from water supply devices become a critical point of control of these entomological poultry pests that have been reported to carry a variety of viral, bacterial and eukaryotic parasites.Los insectos son muy comunes en las instalaciones de la industria avícola y diferentes medidas de bioseguridad se aplican para evitar su propagación debido al hecho que pueden acarrear agentes patógenos. Por lo tanto, es de suma importancia saber qué insectos comúnmente están presentes en los galpones avícolas para optimizar los protocolos de control. Ya que la información sobre este tema es escasa, el objetivo de la presente investigación fue determinar los principales grupos taxonómicos de insectos presentes en el guano de una granja avícola industrial en la zona central de Chile. Las muestras de guano fueron recolectadas en una granja avícola en la Región de Valparaíso, Chile, de áreas adyacentes
Directory of Open Access Journals (Sweden)
PABLO AGUSTO
2006-12-01
them are endemic species, well adapted to xeric environments. We studied the taxonomic structure of the scorpiofauna with regards to the plant formations present in the transitional coastal desert of Chile (25-32º S. Captures of scorpions were conducted with pitfall traps and UV light. Data from de field were complemented from literature and reference material. We identified the presence of 9 species in a total of 226 specimens captured, in the families Bothriuridae and Iuridae. The most abundant genera of Bothriuridae, represented by eight species, were Brachistosternus and Bothriurus, with 55.4 % and 11 % respectively of total captured specimens. Regarding Brachistosternus, Br. (Leptosternus roigalsinai was the most abundant species, with 38.9 % of total captured specimens. Caraboctonus keyserlingi (Iuridae made the 33.2 % of total captured specimens. The highest species richness of scorpions, with six and seven species were respectively, the plant formations of the coastal desert of Huasco (27°52' S, 71°05' W; 29°24' S, 71°18' W and those of the coastal shrubby steppe (29°24' S, 71°18' W; 30°34' S, 71°42' W. The coastal deserts of Tal-Tal (23°52' S, 70°30' W; 27°51' S, 71°05' W and Huasco presented exclusive species. The analysis of correspondence showed that, to the scorpiofauna studied, the coastal shrubby steppe would represent a transitional zone of geographic distribution. Finally, we discussed in function of substrate preference, some aspects related to habitat occupation showed by some of the recorded species
ESO and Chile: 10 Years of Productive Scientific Collaboration
2006-06-01
ESO and the Government of Chile launched today the book "10 Years Exploring the Universe", written by the beneficiaries of the ESO-Chile Joint Committee. This annual fund provides grants for individual Chilean scientists, research infrastructures, scientific congresses, workshops for science teachers and astronomy outreach programmes for the public. In a ceremony held in Santiago on 19 June 2006, the European Organisation for Astronomical Research in the Southern Hemisphere (ESO) and the Chilean Ministry of Foreign Affairs marked the 10th Anniversary of the Supplementary Agreement, which granted to Chilean astronomers up to 10 percent of the total observing time on ESO telescopes. This agreement also established an annual fund for the development of astronomy, managed by the so-called "ESO-Chile Joint Committee". ESO PR Photo 21/06 ESO PR Photo 21/06 Ten Years ESO-Chile Agreement Ceremony The celebration event was hosted by ESO Director General, Dr. Catherine Cesarsky, and the Director of Special Policy for the Chilean Ministry of Foreign Affairs, Ambassador Luis Winter. "ESO's commitment is, and always will be, to promote astronomy and scientific knowledge in the country hosting our observatories", said ESO Director General, Dr. Catherine Cesarsky. "We hope Chile and Europe will continue with great achievements in this fascinating joint adventure, the exploration of the universe." On behalf of the Government of Chile, Ambassador Luis Winter outlined the historical importance of the Supplementary Agreement, ratified by the Chilean Congress in 1996. "Such is the magnitude of ESO-Chile Joint Committee that, only in 2005, this annual fund represented 8 percent of all financing sources for Chilean astronomy, including those from Government and universities", Ambassador Winter said. The ESO Representative and Head of Science in Chile, Dr. Felix Mirabel, and the appointed Chilean astronomer for the ESO-Chile Joint Committee, Dr. Leonardo Bronfman, also took part in the
Species delimitation in taxonomically difficult fungi: the case of Hymenogaster.
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Benjamin Stielow
Full Text Available BACKGROUND: False truffles are ecologically important as mycorrhizal partners of trees and evolutionarily highly interesting as the result of a shift from epigeous mushroom-like to underground fruiting bodies. Since its first description by Vittadini in 1831, inappropriate species concepts in the highly diverse false truffle genus Hymenogaster has led to continued confusion, caused by a large variety of prevailing taxonomical opinions. METHODOLOGY: In this study, we reconsidered the species delimitations in Hymenogaster based on a comprehensive collection of Central European taxa comprising more than 140 fruiting bodies from 20 years of field work. The ITS rDNA sequence dataset was subjected to phylogenetic analysis as well as clustering optimization using OPTSIL software. CONCLUSIONS: Among distinct species concepts from the literature used to create reference partitions for clustering optimization, the broadest concept resulted in the highest agreement with the ITS data. Our results indicate a highly variable morphology of H. citrinus and H. griseus, most likely linked to environmental influences on the phenology (maturity, habitat, soil type and growing season. In particular, taxa described in the 19(th century frequently appear as conspecific. Conversely, H. niveus appears as species complex comprising seven cryptic species with almost identical macro- and micromorphology. H. intermedius and H. huthii are described as novel species, each of which with a distinct morphology intermediate between two species complexes. A revised taxonomy for one of the most taxonomically difficult genera of Basidiomycetes is proposed, including an updated identification key. The (semi-automated selection among species concepts used here is of importance for the revision of taxonomically problematic organism groups in general.
Taxonomic and Thematic Organisation of Proper Name Conceptual Knowledge
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Sebastian J. Crutch
2011-01-01
Full Text Available We report the investigation of the organisation of proper names in two aphasic patients (NBC and FBI. The performance of both patients on spoken word to written word matching tasks was inconsistent, affected by presentation rate and semantic relatedness of the competing responses, all hallmarks of a refractory semantic access dysphasia. In a series of experiments we explored the semantic relatedness effects within their proper name vocabulary, including brand names and person names. First we demonstrated the interaction between very fine grain organisation and personal experience, with one patient with a special interest in the cinema demonstrating higher error rates when identifying the names of actors working in a similar film genre (e.g. action movies: Arnold Schwarzenegger, Bruce Willis, Sylvester Stallone, Mel Gibson than those working in different genres (e.g. Arnold Schwarzenegger, Gregory Peck, Robin Williams, Gene Kelly. Second we compared directly two potential principles of semantic organisation – taxonomic and thematic. Furthermore we considered these principles of organisation in the context of the individuals' personal knowledge base. We selected topics matching the interests and experience of each patient, namely cinema and literature (NBC and naval history (FBI. The stimulus items were arranged in taxonomic arrays (e.g. Jane Austen, Emily Bronte, Agatha Christie, thematic arrays (e.g. Jane Austen, Pride and Prejudice, Mr Darcy, and unrelated arrays (e.g. Jane Austen, Wuthering Heights, Hercule Poirot. We documented that different patterns of taxonomic and thematic organisation were constrained by whether the individual has limited knowledge, moderate knowledge or detailed knowledge of a particular vocabulary. It is suggested that moderate proper name knowledge is primarily organised by taxonomy whereas extensive experience results in a more detailed knowledge base in which theme is a powerful organising principle.
Taxonomic and thematic organisation of proper name conceptual knowledge.
Crutch, Sebastian J; Warrington, Elizabeth K
2011-01-01
We report the investigation of the organisation of proper names in two aphasic patients (NBC and FBI). The performance of both patients on spoken word to written word matching tasks was inconsistent, affected by presentation rate and semantic relatedness of the competing responses, all hallmarks of a refractory semantic access dysphasia. In a series of experiments we explored the semantic relatedness effects within their proper name vocabulary, including brand names and person names. First we demonstrated the interaction between very fine grain organisation and personal experience, with one patient with a special interest in the cinema demonstrating higher error rates when identifying the names of actors working in a similar film genre (e.g., action movies: Arnold Schwarzenegger, Bruce Willis, Sylvester Stallone, Mel Gibson) than those working in different genres (e.g., Arnold Schwarzenegger, Gregory Peck, Robin Williams, Gene Kelly). Second we compared directly two potential principles of semantic organisation - taxonomic and thematic. Furthermore we considered these principles of organisation in the context of the individuals' personal knowledge base. We selected topics matching the interests and experience of each patient, namely cinema and literature (NBC) and naval history (FBI). The stimulus items were arranged in taxonomic arrays (e.g., Jane Austen, Emily Bronte, Agatha Christie), thematic arrays (e.g., Jane Austen, Pride and Prejudice, Mr Darcy), and unrelated arrays (e.g., Jane Austen, Wuthering Heights, Hercule Poirot). We documented that different patterns of taxonomic and thematic organisation were constrained by whether the individual has limited knowledge, moderate knowledge or detailed knowledge of a particular vocabulary. It is suggested that moderate proper name knowledge is primarily organised by taxonomy whereas extensive experience results in a more detailed knowledge base in which theme is a powerful organising principle.
Taxonomic diversity and distinctness indices in assessment of weed communities
Magdalena Jastrzębska; Maria Wanic; Wiesław P. Jastrzębski; Marta K. Kostrzewska
2012-01-01
This paper contains an analysis of taxonomic weed biodiversity in the cultivation of spring barley in the period of 1990-2004, grown in crop rotation after potato with a 25% share of this cereal (potato - spring barley - field pea - winter triticale) as well as in crop rotation with its 75% share (potato - spring barley - spring barley - spring barley) in which barley was grown once and twice after the same barley crop. No weed control was used in the present experiment. Every year in the spr...
Partial migration in fishes: definitions, methodologies and taxonomic distribution
DEFF Research Database (Denmark)
Chapman, B B; Skov, C; Hulthén, K;
2012-01-01
Partial migration, where populations are composed of both migratory and resident individuals, is extremely widespread across the animal kingdom. Researchers studying fish movements have long recognized that many fishes are partial migrants, however, no detailed taxonomic review has ever been...... published. In addition, previous work and synthesis has been hampered by a varied lexicon associated with this phenomenon in fishes. In this review, definitions and important concepts in partial migration research are discussed, and a classification system of the different forms of partial migration...
El Parque Portal Bicentenario en Santiago de Chile / Portal Bicentennial Park in Santiago de Chile
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Beach Lobos, Myriam;
2007-06-01
Full Text Available Se presenta los principios que orientaron el diseño del Parque Portal Bicentenario, un parque de 50 hás. que será el eje principal de la nueva urbanización “Ciudad Parque Bicentenario”, actualmente en construcción en los terrenos del ex aeropuerto de Los Cerrillos en Santiago de Chile.The following text was submitted to the Architecture Competition together with the project drawings. It presents the principles that leaded the design. The 123 acres park will be the main axis of a new urban development in Santiago “Ciudad Parque Bicentenario” at present under construction on the area occupied by the former Cerrillos Airport, Santiago de Chile.
CASO DE ESTUDIO: LA FUNDACION COCA-COLA CHILE
JORGE HERRERA
2006-01-01
This case gives an overview of the Coca-Cola System in Chile and focuses on the Coca-Cola Chile Foundation (CCFCH), a non-profit organization dedicated to education. Created in 1992 with donations from Coca-Cola de Chile S.A. (CCCH) and the bottling companies Embotelladora Andina S.A., Coca-Cola Embonor S.A. and Coca-Cola Polar S.A., the foundation now faces an expansion dilemma in its most important program, the TAVEC Laboratories. Under this program the CCFCH donated interactive scientific ...
[Ecology and health in Chile: present and future development].
Oyarzún, M
1997-09-01
In response to the progressive environmental deterioration, the Ecological Society of America has made a proposal, called "Sustainable Biosphere Initiative", to do research, teaching and decision making processes on biodiversity, global change and the effects of human activities on environment. The goal of appropriate environmental protection and welfare for mankind includes health and quality of life. Presently, Chile faces a number of environmental problems such as pollution, excessive urban growth, loss of agricultural areas, disposal of solid waste and species extinction. The lack of education and information in Chile, on these problems, is worrisome. The role of universities to overcome this deficit should be crucial in the future sustainable development of Chile.
Alleviating extreme poverty in Chile: The short term effects of Chile Solidario
Galasso, Emanuela
2011-01-01
This paper evaluates the effect of an anti-poverty program, Chile Solidario, during its first two years of operation. We find that the program tends to increases significantly their take-up of cash assistance programs and of social programs for housing and employment, and to improve education and health outcomes for participating households. There is no evidence that the participation to employment program translates into improved employment or income outcomes in the short term. Finally, we p...
LA NOVELA DE LA DICTADURA EN CHILE The novel of the dictatorship's period in Chile
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Mario Lulo C
2009-12-01
Full Text Available Para un sector de la crítica y de la academia chilena, la gran novela de la Dictadura es una asignatura pendiente. En este artículo se problematiza este tema mediante la formulación de una hipótesis según la cual una serie de novelas aparecidas en Chile entre 1977 y 2006 cumplen con la función de narrar -desde su fragmentariedad- las causas y consecuencias del 11 de septiembre de 1973. Así, busca plantear las bases epistemológicas e históricas que posibiliten llevar a cabo una investigación de mayor alcance acerca del problema del papel de la novela durante y después de la Dictadura.For many critics and scholars the great novel of the dictatorship's period in Chile still remains a pending matter. This article, on the contrary, hypothesizes on the existence of a significant number of novéis published in Chile between 1977 and 2006, which out of their fragmentary character and peculiarity give a proper account of the causes and consequences of the coup d'état held on September llth 1973. The article seeks to set a preliminary basis for an epistemological discussion and further major research about the role of the Chilean novel, in the historical context of post modernity, during and after the dictatorship's era.
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Cabieses Baltica
2012-11-01
Full Text Available Abstract Background Undocumented immigrants are likely to be missing from population databases, making it impossible to identify an accurate sampling frame in migration research. No population-based data has been collected in Chile regarding the living conditions and health status of undocumented immigrants. However, the CASEN survey (Caracterizacion Socio- Economica Nacional asked about migration status in Chile for the first time in 2006 and provides an opportunity to set the base for future analysis of available migration data. We explored the living conditions and health of self-reported immigrants and respondents who preferred not to report their migration status in this survey. Methods Cross-sectional secondary analysis of CASEN survey in Chile in 2006. Outcomes: any disability, illness/accident, hospitalization/surgery, cancer/chronic condition (all binary variables; and the number of medical/emergency attentions received (count variables. Covariates: Demographics (age, sex, marital status, urban/rural, ethnicity, socioeconomic status (education level, employment status and household income, and material standard of living (overcrowding, sanitation, housing quality. Weighted regression models were estimated for each health outcome, crude and adjusted by sets of covariates, in STATA 10.0. Results About 1% of the total sample reported being immigrants and 0.7% preferred not to report their migration status (Migration Status - Missing Values; MS-MV. The MS-MV lived in more deprived conditions and reported a higher rate of health problems than immigrants. Some gender differences were observed by health status among immigrants and the MS-MV but they were not statistically significant. Regressions indicated that age, sex, SES and material factors consistently affected MS-MVs’ chance of presenting poor health and these patterns were different to those found among immigrants. Great heterogeneity in both the MS-MV and the immigrants, as
An Empirical State Error Covariance Matrix for Batch State Estimation
Frisbee, Joseph H., Jr.
2011-01-01
State estimation techniques serve effectively to provide mean state estimates. However, the state error covariance matrices provided as part of these techniques suffer from some degree of lack of confidence in their ability to adequately describe the uncertainty in the estimated states. A specific problem with the traditional form of state error covariance matrices is that they represent only a mapping of the assumed observation error characteristics into the state space. Any errors that arise from other sources (environment modeling, precision, etc.) are not directly represented in a traditional, theoretical state error covariance matrix. Consider that an actual observation contains only measurement error and that an estimated observation contains all other errors, known and unknown. It then follows that a measurement residual (the difference between expected and observed measurements) contains all errors for that measurement. Therefore, a direct and appropriate inclusion of the actual measurement residuals in the state error covariance matrix will result in an empirical state error covariance matrix. This empirical state error covariance matrix will fully account for the error in the state estimate. By way of a literal reinterpretation of the equations involved in the weighted least squares estimation algorithm, it is possible to arrive at an appropriate, and formally correct, empirical state error covariance matrix. The first specific step of the method is to use the average form of the weighted measurement residual variance performance index rather than its usual total weighted residual form. Next it is helpful to interpret the solution to the normal equations as the average of a collection of sample vectors drawn from a hypothetical parent population. From here, using a standard statistical analysis approach, it directly follows as to how to determine the standard empirical state error covariance matrix. This matrix will contain the total uncertainty in the
Covariate-adjusted confidence interval for the intraclass correlation coefficient.
Shoukri, Mohamed M; Donner, Allan; El-Dali, Abdelmoneim
2013-09-01
A crucial step in designing a new study is to estimate the required sample size. For a design involving cluster sampling, the appropriate sample size depends on the so-called design effect, which is a function of the average cluster size and the intracluster correlation coefficient (ICC). It is well-known that under the framework of hierarchical and generalized linear models, a reduction in residual error may be achieved by including risk factors as covariates. In this paper we show that the covariate design, indicating whether the covariates are measured at the cluster level or at the within-cluster subject level affects the estimation of the ICC, and hence the design effect. Therefore, the distinction between these two types of covariates should be made at the design stage. In this paper we use the nested-bootstrap method to assess the accuracy of the estimated ICC for continuous and binary response variables under different covariate structures. The codes of two SAS macros are made available by the authors for interested readers to facilitate the construction of confidence intervals for the ICC. Moreover, using Monte Carlo simulations we evaluate the relative efficiency of the estimators and evaluate the accuracy of the coverage probabilities of a 95% confidence interval on the population ICC. The methodology is illustrated using a published data set of blood pressure measurements taken on family members. PMID:23871746
Newton law in covariant unimodular F(R) gravity
Nojiri, S.; Odintsov, S. D.; Oikonomou, V. K.
2016-09-01
We investigate the Newton law in the unimodular F(R) gravity. In the standard F(R) gravity, due to the extra scalar mode, there often appear the large corrections to the Newton law and such models are excluded by the experiments and/or the observations. In the unimodular F(R) gravity, however, the extra scalar mode become not to be dynamical due to the unimodular constraint and there is not any correction to the Newton law. Even in the unimodular Einstein gravity, the Newton law is reproduced but the mechanism is a little bit different from that in the unimodular F(R) gravity. We also investigate the unimodular F(R) gravity in the covariant formulation. In the covariant formulation, we include the three-form field. We show that the three-form field could not have any unwanted property, like ghost nor correction to the Newton law. In the covariant formulation, however, the above extra scalar mode becomes dynamical and could give a correction to the Newton law. We also show that there are no difference in the Friedmann-Robertson-Walker (FRW) dynamics in the non-covariant and covariant formulation.
Covariance measurement in the presence of non-synchronous trading and market microstructure noise
J.E. Griffin; R.C.A. Oomen
2011-01-01
This paper studies the problem of covariance estimation when prices are observed non-synchronously and contaminated by i.i.d. microstructure noise. We derive closed form expressions for the bias and variance of three popular covariance estimators, namely realised covariance, realised covariance plus
Ruiz-Rudolph, Pablo; Arias, Nelson; Pardo, Sandra; Meyer, Marianne; Mesías, Stephanie; Galleguillos, Claudio; Schiattino, Irene; Gutiérrez, Luis
2016-01-01
Chile suffers significant pollution from large industrial emitters associated with the mining, metal processing, paper production, and energy industries. The aim of this research was to determine whether the presence of large industrial facilities (i.e. coal- and oil-fired power plants, pulp and paper mills, mining facilities, and smelters) affects mortality and morbidity rates in Chile. For this, we conducted an ecological study that used Chilean communes as small-area observation units to assess mortality and morbidity. Public databases provided information on large pollution sources relevant to Chile. The large sources studied were oil- and coal-fired power plants, copper smelters, pulp and paper mills, and large mining facilities. Large sources were filtered by first year of production, type of process, and size. Mortality and morbidity data were acquired from public national databases, with morbidity being estimated from hospitalization records. Cause-specific rates were calculated for the main outcomes: cardiovascular, respiratory, cancer; and other more specific health outcomes. The impact of the large pollution sources was estimated using Bayesian models that included spatial correlation, overdispersion, and other covariates. Large and significant increases in health risks (around 20%-100%) were found for communes with power plants and smelters for total, cardiovascular, respiratory, all-cancer, and lung cancer mortality. Higher hospitalization rates for cardiovascular disease, respiratory disease, cancer, and pneumonia (20-100%) were also found for communes with power plants and smelters. The impacts were larger for men than women in terms of both mortality and hospitalizations. The impacts were also larger when the sources were analyzed as continuous (production volume) rather than dichotomous (presence/absence) variables. In conclusion, significantly higher rates of total cardiovascular, respiratory, all-cancer and lung cancer mortality and
Phylogenetic analysis and taxonomic revision of Physodactylinae (Coleoptera, Elateridae
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Simone Policena Rosa
2014-01-01
Full Text Available A phylogeny based on male morphological characters and taxonomic revision of the Physodactylinae genera are presented. The phylogenetic analysis based on 66 male characters resulted in the polyphyly of Physodactylinae which comprises four independent lineages. Oligostethius and Idiotropia from Africa were found to be sister groups. Teslasena from Brazil was corroborated as belonging to Cardiophorinae clade. The South American genera Physodactylus and Dactylophysus were found to be sister groups and phylogenetically related to Heterocrepidius species. The Oriental Toxognathus resulted as sister group of that clade plus (Dicrepidius ramicornis (Lissomus sp, Physorhynus erythrocephalus. Taxonomic revisions include diagnoses and redescriptions of genera and distributional records and illustrations of species. Key to species of Teslasena, Toxognathus, Dactylophysus and Physodactylus are also provided. Teslasena lucasi is synonymized with T. femoralis. A new species of Dactylophysus is described, D. hirtus sp. nov., and lectotypes are designated to non-conspecific D. mendax sensu Fleutiaux and Heterocrepidius mendax Candèze. Physodactylus niger is removed from synonymy under P. oberthuri; P. carreti is synonymized with P. niger; P. obesus and P. testaceus are synonymized with P. sulcatus. Nine new species are described in Physodactylus: P. asper sp. nov., P. brunneus sp. nov., P. chassaini sp. nov., P. flavifrons sp. nov., P. girardi sp. nov., P. gounellei sp. nov., P. latithorax sp. nov., P. patens sp. nov. and P. tuberculatus sp. nov.
The taxonomic status of Rhipicephalus sanguineus (Latreille, 1806).
Nava, Santiago; Estrada-Peña, Agustín; Petney, Trevor; Beati, Lorenza; Labruna, Marcelo B; Szabó, Matias P J; Venzal, José M; Mastropaolo, Mariano; Mangold, Atilio J; Guglielmone, Alberto A
2015-02-28
The brown dog tick, Rhipicephalus sanguineus sensu stricto, is a species with considerable public health and economic importance. However, the taxonomic status of this species is far from resolved. After more than 110 years of scientific work on R. sanguineus s.s., the situation is that there is no type, no solid description, nor is there a consensus about the range of morphological variability within the species. Recent findings based on laboratory crosses and molecular genetics strongly suggest that there are several entities grouped under the same name. Here we review the history of the taxon, and we point out the caveats behind any further work on this tick. The current taxonomic status of R. sanguineus s.s. thus lacks an informative original description, and is based on the existence of several morphological descriptions based on ticks originating from different populations, which show, in some cases, biological incompatibility and significant genetic divergence. We suggests that as a result it is not possible to assign the specific name R. sanguineus s.s. to any population. Further work is required based on the rules issued by the International Code of Zoological Nomenclature to clearly define the morphological range of the different populations. PMID:25560924
TRANSPARENCIA Y LEYES SECRETAS EN CHILE
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Pablo Contreras V.
2010-01-01
Full Text Available El autor analiza el problema de constitucionalidad de las leyes secretas en Chile, en razón de las modificaciones introducidas a la Constitución en el 2005. Primero, describe brevemente el fundamento sobre la publicidad de la ley en el Estado Democrático. Luego, se analiza el nuevo principio constitucional de publicidad establecido en el artículo 8º de la Constitución. Adicionalmente, se examina la constitucionalidad de las leyes secretas desde dos puntos de vista: confrontando la compatibilidad con el principio general de transparencia -como base de la institucionalidad- y analizando la afectación en el contenido esencial del derecho fundamental de acceso a la información pública.
Epidemiology of Vibrio parahaemolyticus outbreaks, southern Chile.
Harth, Erika; Matsuda, Luis; Hernández, Cristina; Rioseco, Maria L; Romero, Jaime; González-Escalona, Narjol; Martínez-Urtaza, Jaime; Espejo, Romilio T
2009-02-01
Disease outbreaks caused by Vibrio parahaemolyticus in Puerto Montt, Chile, began in 2004 and reached a peak in 2005 at 3,600 clinical cases. Until 2006, every analyzed case was caused by the serovar O3:K6 pandemic strain. In the summer of 2007, only 475 cases were reported; 73% corresponded to the pandemic strain. This decrease was associated with a change in serotype of many pandemic isolates to O3:K59 and the emergence of new clinical strains. One of these strains, associated with 11% of the cases, was genotypically different from the pandemic strain but contained genes that were identical to those found on its pathogenicity island. These findings suggest that pathogenicity-related genes were laterally transferred from the pandemic strain to one of the different V. parahaemolyticus groups comprising the diverse and shifting bacterial population in shellfish in this region. PMID:19193258
Privatization And Vouchers In Colombia And Chile
Arenas, Alberto
2004-07-01
The voucher model of financing schooling is becoming increasingly common throughout Latin America, with at least 12 countries using vouchers or voucher-like schemes. The present study focuses on the voucher models of Colombia and Chile, which have the most extensive programs of this type and those of the longest standing in the region. Using empirical evidence, the author compares the two models along four evaluative dimensions: educational quality, segregation, choice and socialization. After weighing the successes and weaknesses of each system, he concludes that, among other characteristics, the most effective and equitable voucher model features: (a) a flexible interpretation of educational quality; (b) financial grants which target solely the poor; (c) vouchers which cover the entire cost of tuition; (d) open enrolment at participating schools; (e) the participation of both secular and religious private schools; (f) accessible and meaningful information to parents; and (g) strong systems of accountability.
Three halls for music performance in Chile
Delannoy, Jaime; Heuffemann, Carolina; Ramirez, Daniel; Galvez, Fernando
2002-11-01
The primary purpose of this work was to investigate about the present acoustic conditions of used architectonic spaces in Santiago of Chile for orchestras of classic music performance. The studied halls were three: Aula Magna Universidad de Santiago, Teatro Municipal de Nunoa, and Teatro Baquedano. The used methodology was based on studies made by L. Beranek, M. Barron, among others, in concert halls worldwide. As it guides, for the measurement procedure, physical parameters RT, EDT, C50, C80, LF, BR, G, U50 were evaluated according to norm ISO 3382. On the other hand, it has been defined, to proposal way, a questionnaire of subjective valuation directed to musicians, specialized conductors, and listeners.
A DRONE FLIGHT OVER PARANAL, CHILE
2016-01-01
Aerial clip (shot using a drone and a Go pro) describing ESO's astronomical observatory facilities in the Atacama desert, Northern Chile. Locations covered by the drone flight include Cerro Paranal, with the Residencia (external and internal views) and the Very Large Telescope facility on Cerro Paranal, from above and with a peek into Unit Telescope 1 and its 8,2 m diameter mirror; final image on Cerro Armazones, the site chosen for building ESO's next telescope, the E-ELT (European Extremely Large Telescope). With a 39-metre main mirror, it will be the largest optical/near-infrared telescope in the world. The Argentinian Codillera with the Llullaillaco volcano are visible in the background.
Improving the effectiveness of rural development policy in Chile
Carter Leal, L.M.
2016-01-01
In Chile, agriculture remains a key economic factor for rural development. Accordingly, the Chilean government, through the Agricultural Development Institute (INDAP), provides financial support for fostering entrepreneurship among small farmers to enable them to become more competitive in global ma
Galaxy-galaxy lensing estimators and their covariance properties
Singh, Sukhdeep; Seljak, Uroš; Slosar, Anže; Gonzalez, Jose Vazquez
2016-01-01
We study the covariance properties of real space correlation function estimators -- primarily galaxy-shear correlations, or galaxy-galaxy lensing -- using SDSS data for both shear catalogs and lenses (specifically the BOSS LOWZ sample). Using mock catalogs of lenses and sources, we disentangle the various contributions to the covariance matrix and compare them with a simple analytical model. We show that not subtracting the lensing measurement around random points from the measurement around the lens sample is equivalent to performing the measurement using the density field instead of the over-density field, and that this leads to a significant error increase due to an additional term in the covariance. Therefore, this subtraction should be performed regardless of its beneficial effects on systematics. Comparing the error estimates from data and mocks for estimators that involve the over-density, we find that the errors are dominated by the shape noise and lens clustering, that empirically estimated covarianc...
Femtosecond Studies Of Coulomb Explosion Utilizing Covariance Mapping
Card, D A
2000-01-01
The studies presented herein elucidate details of the Coulomb explosion event initiated through the interaction of molecular clusters with an intense femtosecond laser beam (≥1 PW/cm2). Clusters studied include ammonia, titanium-hydrocarbon, pyridine, and 7-azaindole. Covariance analysis is presented as a general technique to study the dynamical processes in clusters and to discern whether the fragmentation channels are competitive. Positive covariance determinations identify concerted processes such as the concomitant explosion of protonated cluster ions of asymmetrical size. Anti- covariance mapping is exploited to distinguish competitive reaction channels such as the production of highly charged nitrogen atoms formed at the expense of the protonated members of a cluster ion ensemble. This technique is exemplified in each cluster system studied. Kinetic energy analyses, from experiment and simulation, are presented to fully understand the Coulomb explosion event. A cutoff study strongly suggests that...
Data Covariances from R-Matrix Analyses of Light Nuclei
Energy Technology Data Exchange (ETDEWEB)
Hale, G.M., E-mail: ghale@lanl.gov; Paris, M.W.
2015-01-15
After first reviewing the parametric description of light-element reactions in multichannel systems using R-matrix theory and features of the general LANL R-matrix analysis code EDA, we describe how its chi-square minimization procedure gives parameter covariances. This information is used, together with analytically calculated sensitivity derivatives, to obtain cross section covariances for all reactions included in the analysis by first-order error propagation. Examples are given of the covariances obtained for systems with few resonances ({sup 5}He) and with many resonances ({sup 13}C ). We discuss the prevalent problem of this method leading to cross section uncertainty estimates that are unreasonably small for large data sets. The answer to this problem appears to be using parameter confidence intervals in place of standard errors.
Manifestly gauge-covariant representation of scalar and fermion propagators
Latosiński, Adam
2015-01-01
A new way to write the massive scalar and fermion propagators on a background of a weak gauge field is presented. They are written in a form that is manifestly gauge-covariant up to several additional terms that can be written as boundary terms in momentum space. These additional terms violate Ward-Takahashi identities and need to be renormalized by appropriate counterterms if the complete theory is to be gauge-covariant. This form makes it possible to calculate many amplitudes in a manifestly gauge-covariant way (at the same time reducing the number of Feynman diagrams). It also allows to express some counterterms in a way independent of the regularization scheme and provides an easy way to derive the anomalous term affecting the chiral current conservation.
Full covariance of CMB and lensing reconstruction power spectra
Peloton, Julien; Lewis, Antony; Carron, Julien; Zahn, Oliver
2016-01-01
CMB and lensing reconstruction power spectra are powerful probes of cosmology. However they are correlated, since the CMB power spectra are lensed and the lensing reconstruction is constructed using CMB multipoles. We perform a full analysis of the auto- and cross-covariances, including polarization power spectra and minimum variance lensing estimators, and compare with simulations of idealized future CMB-S4 observations. Covariances sourced by fluctuations in the unlensed CMB and instrumental noise can largely be removed by using a realization-dependent subtraction of lensing reconstruction noise, leaving a relatively simple covariance model that is dominated by lensing-induced terms and well described by a small number of principal components. The correlations between the CMB and lensing power spectra will be detectable at the level of $\\sim 5\\sigma$ for a CMB-S4 mission, and neglecting those could underestimate some parameter error bars by several tens of percent. However we found that the inclusion of ext...
Adaptive Covariance Inflation in a Multi-Resolution Assimilation Scheme
Hickmann, K. S.; Godinez, H. C.
2015-12-01
When forecasts are performed using modern data assimilation methods observation and model error can be scaledependent. During data assimilation the blending of error across scales can result in model divergence since largeerrors at one scale can be propagated across scales during the analysis step. Wavelet based multi-resolution analysiscan be used to separate scales in model and observations during the application of an ensemble Kalman filter. However,this separation is done at the cost of implementing an ensemble Kalman filter at each scale. This presents problemswhen tuning the covariance inflation parameter at each scale. We present a method to adaptively tune a scale dependentcovariance inflation vector based on balancing the covariance of the innovation and the covariance of observations ofthe ensemble. Our methods are demonstrated on a one dimensional Kuramoto-Sivashinsky (K-S) model known todemonstrate non-linear interactions between scales.
Residual noise covariance for Planck low-resolution data analysis
Keskitalo, R; Cabella, P; Kisner, T; Poutanen, T; Stompor, R; Bartlett, J G; Borrill, J; Cantalupo, C; De Gasperis, G; De Rosa, A; de Troia, G; Eriksen, H K; Finelli, F; Górski, K M; Gruppuso, A; Hivon, E; Jaffe, A; Keihanen, E; Kurki-Suonio, H; Lawrence, C R; Natoli, P; Paci, F; Polenta, G; Rocha, G
2009-01-01
Aims: Develop and validate tools to estimate residual noise covariance in Planck frequency maps. Quantify signal error effects and compare different techniques to produce low-resolution maps. Methods: We derive analytical estimates of covariance of the residual noise contained in low-resolution maps produced using a number of map-making approaches. We test these analytical predictions using Monte Carlo simulations and their impact on angular power spectrum estimation. We use simulations to quantify the level of signal errors incurred in different resolution downgrading schemes considered in this work. Results: We find an excellent agreement between the optimal residual noise covariance matrices and Monte Carlo noise maps. For destriping map-makers, the extent of agreement is dictated by the knee frequency of the correlated noise component and the chosen baseline offset length. The significance of signal striping is shown to be insignificant when properly dealt with. In map resolution downgrading, we find that...
Research training in dental undergraduate curriculum in Chile.
Ximena Moreno
2014-01-01
ABSTRACT Research plays a central role in professional training in dentistry. There is a clear recommendation to include a minimum training in biomedical research at undergraduate level. In Chile, there is no standardized curriculum structure including research training for undergraduate students. Objective: To describe the presence of research courses in the undergraduate dental curriculum in Chile during 2014. Methodology: A descriptive cross-sectional study. The curriculum for all Chilean...
Beyond Income: A Study of Multidimensional Poverty in Chile
Bronfman, Javier
2014-01-01
Using the latest nationally representative household survey for Chile, this paper empirically assesses multidimensional poverty both at the national and subnational level. Based on the Alkire-Foster method and focusing on four dimensions of well-being –education, health, income and living standard– this study estimates the level and depth of multidimensional poverty for Chile in 2011. At national level, the results show that fewer individuals are subject to multidimensional poverty compared t...
Energy Technology Data Exchange (ETDEWEB)
Walsh, Stephen J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tardiff, Mark F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2007-10-01
Removing background from hyperspectral scenes is a common step in the process of searching for materials of interest. Some approaches to background subtraction use spectral library data and require invertible covariance matrices for each member of the library. This is challenging because the covariance matrix can be calculated but standard methods for estimating the inverse requires that the data set for each library member have many more spectral measurements than spectral channels, which is rarely the case. An alternative approach is called shrinkage estimation. This method is investigated as an approach to providing an invertible covariance matrix estimate in the case where the number of spectral measurements is less than the number of spectral channels. The approach is an analytic method for arriving at a target matrix and the shrinkage parameter that modify the existing covariance matrix for the data to make it invertible. The theory is discussed to develop different estimates. The resulting estimates are computed and inspected on a set of hyperspectral data. This technique shows some promise for arriving at an invertible covariance estimate for small hyperspectral data sets.
Chung, W-S.
1996-01-01
In this paper some realization of $gl_q(n)$-covariant oscillators is obtained when $q$ is a root of unity. And the $gl_q(n)$-covariant q-Virasoro algebra is presented by using the $gl_q(n)$-covariant oscillators.
Hitting the right target: taxonomic challenges for, and of, plant invasions
Pyšek, Petr; Hulme, Philip E.; Meyerson, Laura A.; Smith, Gideon F; James S Boatwright; Crouch, Neil R; Figueiredo, Estrela; Llewellyn C. Foxcroft; Jarošík, Vojtěch; Richardson, David M.; Suda, Jan; Wilson, John R. U.
2013-01-01
This paper explores how a lack of taxonomic expertise, and by implication a dearth of taxonomic products such as identification tools, has hindered progress in understanding and managing biological invasions. It also explores how the taxonomic endeavour could benefit from studies of invasive species. We review the literature on the current situation in taxonomy with a focus on the challenges of identifying alien plant species and explore how this has affected the study of biological invasions...
Gauge covariance approach to massive Yang-Mills fields
International Nuclear Information System (INIS)
By observation of the gauge structure introduced in the SU(2) Higgs-Kibble model on the basis of a massless Yang-Mills field theory with gauge covariance, another possible formalism of a massive Yang-Mills field theory with gauge covariance is presented. The formalism exhibits a close analogy to the case of massive abelian-gauge fields. In contrast with the case of the Higgs-Kibble model, no dipole-ghost field is introduced in the formalism. Supplementary conditions for physical states are given in a consistent way. (author)
Relativistic covariant wave equations and acausality in external fields
International Nuclear Information System (INIS)
The author considers linear, finite dimensional, first order relativistic wave equations: (βsup(μ)ideltasub(μ)-β)PSI(x) = 0 with βsup(μ) and β constant matrices. Firstly , the question of the relativistic covariance conditions on these equations is considered. Then the theory of these equations with β non-singular is summarized. Theories with βsup(μ), β square matrices and β singular are also discussed. Non-square systems of covariant relativistic wave equations for arbitrary spin > 1 are then considered. Finally, the interaction with external fields and the acausality problem are discussed. (G.T.H.)
The covariant electromagnetic Casimir effect for real conducting spherical shells
Razmi, H
2016-01-01
Using the covariant electromagnetic Casimir effect (previously introduced for real conducting cylindrical shells [1]), the Casimir force experienced by a spherical shell, under Dirichlet boundary condition, is calculated. The renormalization procedure is based on the plasma cut-off frequency for real conductors. The real case of a gold (silver) sphere is considered and the corresponding electromagnetic Casimir force is computed. In the covariant approach, there isn't any decomposition of fields to TE and TM modes; thus, we do not need to consider the Neumann boundary condition in parallel to the Dirichlet problem and then add their corresponding results.
Covariance and gauge invariance in relativistic theories of gravity
Papini, Giorgio
2014-04-01
Any metric theory of gravity whose interaction with quantum particles is described by a covariant wave equation is equivalent to a vector theory that satisfies Maxwell-type equations identically. This result does not depend on any particular set of field equations for the metric tensor, but only on covariance. It is derived in the linear case, but can be extended to any order of approximation in the metric deviation. In this formulation of the interaction of gravity with matter, angular momentum and momentum are conserved locally.
Covariance and gauge invariance in relativistic theories of gravity
Papini, Giorgio
2014-01-01
Any metric theory of gravity whose interaction with quantum particles is described by a covariant wave equation is equivalent to a vector theory that satisfies Maxwell-type equations identically. This result does not depend on any particular set of field equations for the metric tensor, but only on covariance. It is derived in the linear case, but can be extended to any order of approximation in the metric deviation. In this formulation of the interaction of gravity with matter, angular momentum and momentum are conserved locally.
On Variance and Covariance for Bounded Linear Operators
Institute of Scientific and Technical Information of China (English)
Chia Shiang LIN
2001-01-01
In this paper we initiate a study of covariance and variance for two operators on a Hilbert space, proving that the c-v (covariance-variance) inequality holds, which is equivalent to the CauchySchwarz inequality. As for applications of the c-v inequality we prove uniformly the Bernstein-type incqualities and equalities, and show the generalized Heinz-Kato-Furuta-type inequalities and equalities,from which a generalization and sharpening of Reid's inequality is obtained. We show that every operator can be expressed as a p-hyponormal-type, and a hyponornal-type operator. Finally, some new characterizations of the Furuta inequality are given.
High-dimensional covariance matrix estimation with missing observations
Lounici, Karim
2012-01-01
In this paper, we study the problem of high-dimensional approximately low-rank covariance matrix estimation with missing observations. We propose a simple procedure computationally tractable in high-dimension and that does not require imputation of the missing data. We establish non-asymptotic sparsity oracle inequalities for the estimation of the covariance matrix with the Frobenius and spectral norms, valid for any setting of the sample size and the dimension of the observations. We further establish minimax lower bounds showing that our rates are minimax optimal up to a logarithmic factor.
Directory of Open Access Journals (Sweden)
Valentin A. Stonik
2012-08-01
Full Text Available Literature data about glycosides from sponges (Porifera, Demospongiae are reviewed. Structural diversity, biological activities, taxonomic distribution and biological functions of these natural products are discussed.
Stonik, Valentin A.; Makarieva, Tatyana N.; Kalinin, Vladimir I.; Krasokhin, Vladimir B.; Natalia V. Ivanchina
2012-01-01
Literature data about glycosides from sponges (Porifera, Demospongiae) are reviewed. Structural diversity, biological activities, taxonomic distribution and biological functions of these natural products are discussed.
Leitão, Sofia; Peña, M T; Biernat, Elmar P
2016-01-01
The Covariant Spectator Theory (CST) is used to calculate the mass spectrum and vertex functions of heavy-light and heavy mesons in Minkowski space. The covariant kernel contains Lorentz scalar, pseudoscalar, and vector contributions. The numerical calculations are performed in momentum space, where special care is taken to treat the strong singularities present in the confining kernel. The observed meson spectrum is very well reproduced after fitting a small number of model parameters. Remarkably, a fit to a few pseudoscalar meson states only, which are insensitive to spin-orbit and tensor forces and do not allow to separate the spin-spin from the central interaction, leads to essentially the same model parameters as a more general fit. This demonstrates that the covariance of the chosen interaction kernel is responsible for the very accurate prediction of the spin-dependent quark-antiquark interactions.
The fruit fly programme in Chile
International Nuclear Information System (INIS)
Full text: country. In fact, no species of the genera Ceratitis, Bactrocera, Anastrepha, Dacus and Toxotrypana exist in the country. This programme uses the Fruit fly National Detection System, which includes detection of the pest by trapping and fruit sampling in different areas located between the I and XI Regions of the country. This system is approved by the Chilean trade partners on the basis of the fruit fly-free recognition. For the Chilean fresh fruit exports, this is an important advantage, because there is no need to apply quarantine treatments or any other restriction measure. Chile has also a huge fruit industry, whose export revenues last season reached USD 1,900 million. This fact has permitted to undertake continuously a big effort to maintain that phytosanitary condition. Since Chile is the only fruit-fly free Latin American country, it has to face a continuous biological pressure of fruit flies, mainly C. capitata, to invade its territory. But the country has also some important advantages to prevent flies migrating due to its natural isolation. These natural barriers are the Los Andes ranges in the east, thousands of kilometers of desert in the north, the Pacific Ocean in the west and finally an extremely cold, sub polar climate in the south. This isolation has led to the NPPO officials to believe that the passive spread, through smuggling and hidden fruit in passenger's baggage, to be the most likely source of fruit fly entries. Because of that, Chile has a very strict quarantine system with border control stations at every point of entry. The only exception to the mentioned isolation is Arica Province on the border with Peru. There, SAG applies an area-wide preventative approach through the rearing and release of sterile insects, as well as bait spraying in the border area, which is mainly desert, but has some 'green spots' that allow the fly to alight for resting and feeding. Additionally, through bi-national agreements, common activities are
Flora of the city of Podgorica, Montenegro: Taxonomic analysis
Directory of Open Access Journals (Sweden)
Stešević Danijela
2008-01-01
Full Text Available In this paper we present the taxonomic segment of a floristic study undertaken in the city of Podgorica in the period of 2002-2007. The check-list of spontaneously growing vascular plants includes 1227 species and subspecies belonging to 545 genera and 118 families. The dominant families are Poaceae (11.7%, asteraceae (11.2% and Fabaceae (9.2%. The most abundant genera are Trifolium (2.1%, Euphorbia (1.5%, Carex (1.5%, Bromus (1.3% and Vicia (1.2%. Analysis of the flora of Podgorica in comparison with some other european cities showed that the flora of Podgorica is most similar to that of Rome (Q/S= 0,7.
Marine actinomycetes from Madeira Archipelago preliminary taxonomic studies
Directory of Open Access Journals (Sweden)
Ilda Santos Sanches
2014-06-01
Full Text Available The oceans cover 70 % of the Earth´s surface and harbor most of the planet´s biodiversity. However the microbiological component of this diversity remains relatively unexplored. Marine actinomycetes, are a robust resource of chemically prolific novelty. Producing structurally unique biological active secondary metabolites, generating a valuable source for innovative biotechnology and drug discovery[1,2]. As a consequence, the ecological role of actinomycetes and their marine ecosystems may no longer be neglected. It is crucial to move our research efforts into ocean regions for which we know little or nothing about the indigenous microbial diversity. The Portuguese Archipelago, Madeira is located in the Macaronesian Atlantic region, emerging from the African tectonic plate, found in the extreme south of the Tore-Madeira ridge, has a unique biogeography and biodiversity. These distinctive characteristics combined with the fact that Madeira have never been explored, as far as indigenous marine actinomycetes are concerned, makes it from the scientific point of view, the perfect target for our studies. From 662 marine sediment samples collected along Madeira Archipelago (Figure 1 during June of 2012, covering depths from 10-1310 m, a total of 421 actinomycete strains were isolated. In a previous study, an assemblage of 82 strains was selected for taxonomic identification, having into account representative morphological diversity characteristics of the actinomycetes, isolated from Madeira Archipelago. Based on 16S rRNA gene sequencing, it was observed that the genera Streptomyces, Micromonospora and Salinispora were predominant, 81% [3]. Additionally, in a recent study, our team selected 168 strains with Salinispora look-alike morphological features. From these 28 strains were identified as belonging to the seawater-obligate marine actinomycete genus Salinispora. Representing the first report of Salinispora spp. in the Macaronesian Atlantic Ocean
Effects of land use on taxonomic and functional diversity
DEFF Research Database (Denmark)
Hevia, Violeta; Carmona, Carlos P.; Azcárate, Francisco M.;
2016-01-01
Land-use change is the major driver of biodiversity loss. However, taxonomic diversity (TD) and functional diversity (FD) might respond differently to land-use change, and this response might also vary depending on the biotic group being analysed. In this study, we compare the TD and FD of four...... biotic groups (ants, birds, herbaceous, woody vegetation) among four land-use types that represent a gradient of land-use intensity in a Mediterranean landscape (Mediterranean shrublands, dehesas, mixed-pine forests, olive groves). Analyses were performed separately at two different spatial scales......: the sampling unit scale and the site scale. Land-use intensity effects on TD and FD were quite different and highly varied among the four biotic groups, with no single clear pattern emerging that could be considered general for all organisms. Additive partitioning of species diversity revealed clear...
Memory systems, processes, and tasks: taxonomic clarification via factor analysis.
Bruss, Peter J; Mitchell, David B
2009-01-01
The nature of various memory systems was examined using factor analysis. We reanalyzed data from 11 memory tasks previously reported in Mitchell and Bruss (2003). Four well-defined factors emerged, closely resembling episodic and semantic memory and conceptual and perceptual implicit memory, in line with both memory systems and transfer-appropriate processing accounts. To explore taxonomic issues, we ran separate analyses on the implicit tasks. Using a cross-format manipulation (pictures vs. words), we identified 3 prototypical tasks. Word fragment completion and picture fragment identification tasks were "factor pure," tapping perceptual processes uniquely. Category exemplar generation revealed its conceptual nature, yielding both cross-format priming and a picture superiority effect. In contrast, word stem completion and picture naming were more complex, revealing attributes of both processes. PMID:19507425
Fast and sensitive taxonomic classification for metagenomics with Kaiju
DEFF Research Database (Denmark)
Menzel, Peter; Ng, Kim Lee; Krogh, Anders
2016-01-01
The constantly decreasing cost and increasing output of current sequencing technologies enable large scale metagenomic studies of microbial communities from diverse habitats. Therefore, fast and accurate methods for taxonomic classification are needed, which can operate on increasingly larger...... datasets and reference databases. Recently, several fast metagenomic classifiers have been developed, which are based on comparison of genomic k-mers. However, nucleotide comparison using a fixed k-mer length often lacks the sensitivity to overcome the evolutionary distance between sampled species...... and genomes in the reference database. Here, we present the novel metagenome classifier Kaiju for fast assignment of reads to taxa. Kaiju finds maximum exact matches on the protein-level using the Borrows-Wheeler transform, and can optionally allow amino acid substitutions in the search using a greedy...
Extrafloral nectaries in Combretaceae: morphology, anatomy and taxonomic significance
Directory of Open Access Journals (Sweden)
P. M. Tilney
2004-12-01
Full Text Available Extrafloral nectaries (EFNs in members of the Combretaceae are nectaries not involved with pollination and occurring on vegetative structures; they are believed to attract ants to protect plants against herbivorv by other insects. In the Combretaceae EFNs are reported in species of Terminalia L. and Pteleopsis Engl., putative EFNs in Meiostemon Exell & Stace and Quisqualis L., and an absence of EFNs in Combretum Loefl. and Lumnitzera Willd. EFNs in the family are generally spherical in shape and may be raised, level with the surface or somewhat concave. They are similar in the Terminalia and Pteleopsis species where they display varying degrees of internal zonation and are composed of small cells; those species observed in the field were all found to have functional EFNs. In Meiostemon tetrandrum (Exell Exell & Stace, Quisqualis indica L.. Q. littorea (Engl. Exell and Q. paviflora Gerrard ex Sond.. apparent EFNs lack internal zonation and are composed of enlarged cells; confirmation is required as to whether these are functional . The formation of EFNs appears to be highly flexible. They are usually essentially associated with new growth but their occurrence is sporadic and they do not appear on every leaf or every' branch of a plant. The distribution of EFNs on leaves, when present, is of taxonomic significance to separate species of Pteleopsis and Terminalia: otherwise the presence or absence and distribution of EFNs are too variable and sporadic in occurrence to be of taxonomic significance at the species level. Indiscriminate use of the terms gland and domatium instead of EFN. and possible confusion with damage caused by other organisms, has probably contributed to many of these structures not previously being recorded as EFNs. Floral and extrafloral nectar samples of T. phanerophlebia Engl. & Diels differed in sugar composition.
Fossil struthionid eggshells from Laetoli, Tanzania: Taxonomic and biostratigraphic significance
Harrison, Terry; Msuya, Charles P.
2005-04-01
Recent paleontological investigations at Laetoli and neighboring localities in northern Tanzania have produced a large collection of fossil ostrich eggshells from the Pliocene-aged Laetolil Beds (˜3.5-4.5 Ma) and Ndolanya Beds (˜2.6-2.7 Ma). A detailed analysis of the morphology of the eggshells and their taxonomic affinities indicates that two different species of Struthio are represented. In the Lower Laetolil Beds and in the Upper Laetolil Beds below Tuff 3 a new species is recognized— Struthio kakesiensis. This is replaced in the Upper Laetolil Beds by Struthio camelus, the modern species of ostrich. Since radiometric age determinations are available for the stratigraphic sequence at Laetoli, it is possible to precisely date the first appearance of S. camelus at ˜3.6-3.8 Ma. Comparisons of the Laetoli material with specimens from the well-dated sequences at Lothagam and Kanapoi in northern Kenya, allow the taxonomic and biochronological analysis to be extended back in time to the late Miocene. At about 6.5 Ma, Diamantornis and elephant birds were replaced in East Africa by ostriches belonging to the genus Struthio. Three time-successive species of ostriches are identified in the fossil record of East Africa, beginning with Struthio. cf. karingarabensis (˜6.5-4.2 Ma), followed by S. kakesiensis (˜4.5-3.6 Ma) and then S. camelus (˜3.8 Ma onwards). A similar sequence of taxa has previously been recorded from localities in Namibia, but at these sites there is no possibility to precisely calibrate the ages of the different species using radiometric dating. Nevertheless, the broadly similar evolutionary sequence and the close correspondence in inferred ages for the succession of species in East Africa and Namibia suggest that ostrich eggshells are a very useful tool for biochronological correlation of paleontological sites in sub-Saharan Africa.
A New Test for a Normal Covariance Matrix
Institute of Scientific and Technical Information of China (English)
禹建奇
2015-01-01
The problem of testing the normal covariance matrix equal to a specified matrix is considered.A new Chi-Square test statistic is derived for multivariate normal population.Unlike the likelihood ratio test,the new test is an exact one.
A covariant entropy conjecture on cosmological dynamical horizon
He, Song
2007-01-01
We here propose a covariant entropy conjecture on cosmological dynamical horizon. After the formulation of our conjecture, we test its validity in adiabatically expanding universes with open, flat and closed spatial geometry, where our conjecture can also be viewed as a cosmological version of the generalized second law of thermodynamics in some sense.
Covariation of spectral and nonlinear EEG measures with alpha biofeedback.
Fell, J.; Elfadil, H.; Klaver, P.; Roschke, J.; Elger, C.E.; Fernandez, G.S.E.
2002-01-01
This study investigated how different spectral and nonlinear EEG measures covaried with alpha power during auditory alpha biofeedback training, performed by 13 healthy subjects. We found a significant positive correlation of alpha power with the largest Lyapunov-exponent, pointing to an increased dy
Eddy covariance based methane flux in Sundarbans mangroves, India
Indian Academy of Sciences (India)
Chandra Shekhar Jha; Suraj Reddy Rodda; Kiran Chand Thumaty; A K Raha; V K Dadhwal
2014-07-01
We report the initial results of the methane flux measured using eddy covariance method during summer months from the world’s largest mangrove ecosystem, Sundarbans of India. Mangrove ecosystems are known sources for methane (CH4) having very high global warming potential. In order to quantify the methane flux in mangroves, an eddy covariance flux tower was recently erected in the largest unpolluted and undisturbed mangrove ecosystem in Sundarbans (India). The tower is equipped with eddy covariance flux tower instruments to continuously measure methane fluxes besides the mass and energy fluxes. This paper presents the preliminary results of methane flux variations during summer months (i.e., April and May 2012) in Sundarbans mangrove ecosystem. The mean concentrations of CH4 emission over the study period was 1682 ± 956 ppb. The measured CH4 fluxes computed from eddy covariance technique showed that the study area acts as a net source for CH4 with daily mean flux of 150.22 ± 248.87 mg m−2 day−1. The methane emission as well as its flux showed very high variability diurnally. Though the environmental conditions controlling methane emission is not yet fully understood, an attempt has been made in the present study to analyse the relationships of methane efflux with tidal activity. This present study is part of Indian Space Research Organisation–Geosphere Biosphere Program (ISRO–GBP) initiative under ‘National Carbon Project’.
Experimental Uncertainty and Covariance Information in EXFOR Library
Directory of Open Access Journals (Sweden)
Schillebeeckx P.
2012-05-01
Full Text Available Compilation of experimental uncertainty and covariance information in the EXFOR Library is discussed. Following the presentation of a brief history of information provided in the EXFOR Library, the current EXFOR Formats and their limitations are reviewed. Proposed extensions for neutron-induced reaction cross sections in the fast neutron region and resonance region are also presented.
Spectral Density of Sample Covariance Matrices of Colored Noise
Dolezal, Emil
2008-01-01
We study the dependence of the spectral density of the covariance matrix ensemble on the power spectrum of the underlying multivariate signal. The white noise signal leads to the celebrated Marchenko-Pastur formula. We demonstrate results for some colored noise signals.
On variance estimate for covariate adjustment by propensity score analysis.
Zou, Baiming; Zou, Fei; Shuster, Jonathan J; Tighe, Patrick J; Koch, Gary G; Zhou, Haibo
2016-09-10
Propensity score (PS) methods have been used extensively to adjust for confounding factors in the statistical analysis of observational data in comparative effectiveness research. There are four major PS-based adjustment approaches: PS matching, PS stratification, covariate adjustment by PS, and PS-based inverse probability weighting. Though covariate adjustment by PS is one of the most frequently used PS-based methods in clinical research, the conventional variance estimation of the treatment effects estimate under covariate adjustment by PS is biased. As Stampf et al. have shown, this bias in variance estimation is likely to lead to invalid statistical inference and could result in erroneous public health conclusions (e.g., food and drug safety and adverse events surveillance). To address this issue, we propose a two-stage analytic procedure to develop a valid variance estimator for the covariate adjustment by PS analysis strategy. We also carry out a simple empirical bootstrap resampling scheme. Both proposed procedures are implemented in an R function for public use. Extensive simulation results demonstrate the bias in the conventional variance estimator and show that both proposed variance estimators offer valid estimates for the true variance, and they are robust to complex confounding structures. The proposed methods are illustrated for a post-surgery pain study. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26999553
A Review of Nonparametric Alternatives to Analysis of Covariance.
Olejnik, Stephen F.; Algina, James
1985-01-01
Five distribution-free alternatives to parametric analysis of covariance are presented and demonstrated: Quade's distribution-free test, Puri and Sen's solution, McSweeney and Porter's rank transformation, Burnett and Barr's rank difference scores, and Shirley's general linear model solution. The results of simulation studies regarding Type I…
Conservation laws and covariant equations of motion for spinning particles
Obukhov, Yuri N
2015-01-01
We derive the Noether identities and the conservation laws for general gravitational models with arbitrarily interacting matter and gravitational fields. These conservation laws are used for the construction of the covariant equations of motion for test bodies with minimal and nonminimal coupling.
Covariate-adjusted measures of discrimination for survival data
White, Ian R.; Rapsomaniki, Eleni; Wannamethee, S. G.; Morris, R. W.; Willeit, J.; Willeit, P.; Santer, P.; Kiechl, S.; Wald, N.; Ebrahim, S.; Lawlor, D. A.; Gallacher, J.; Yarnell, J. W G; Ben-Shlomo, Y.; Casiglia, E.; Tikhonoff, V.; Sutherland, S. E.; Nietert, P. J.; Keil, J. E.; Bachman, D. L.; Psaty, B. M.; Cushman, M.; Nordestgaard, B. G.; Tybjærg-Hansen, A.; Frikke-Schmidt, R.; Giampaoli, S.; Palmieri, L.; Panico, S.; Pilotto, L.; Vanuzzo, D.; Simons, L. A.; Friedlander, Y.; McCallum, J.; Price, J. F.; McLachlan, S.; Taylor, J. O.; Guralnik, J. M.; Wallace, R. B.; Kohout, F. J.; Cornoni-Huntley, J. C.; Guralnik, J. M.; Blazer, D. G.; Guralnik, J. M.; Phillips, C. L.; Phillips, C. L.; Guralnik, J. M.; Wareham, N. J.; Khaw, K. T.; Brenner, H.; Schöttker, B.; Müller, H. T.; Rothenbacher, D.; Nissinen, A.; Donfrancesco, C.; Giampaoli, S.; Harald, K.; Jousilahti, P. R.; Vartiainen, E.; Salomaa, V.; D'Agostino, R. B.; Wolf, P. A.; Vasan, R. S.; Daimon, M.; Oizumi, T.; Kayama, T.; Kato, T.; Chetrit, A.; Dankner, R.; Lubin, F.; Welin, L.; Svärdsudd, K.; Eriksson, H.; Lappas, G.; Lissner, L.; Mehlig, K.; Björkelund, C.; Nagel, D.; Kiyohara, Y.; Arima, H.; Ninomiya, T.; Hata, J.; Rodriguez, B.; Dekker, J. M.; Nijpels, G.; Stehouwer, C. D A; Iso, H.; Kitamura, A.; Yamagishi, K.; Noda, H.; Goldbourt, U.; Kauhanen, J.; Salonen, J. T.; Tuomainen, T. P.; Meade, T. W.; DeStavola, B. L.; Blokstra, A.; Verschuren, W. M M; Cushman, M.; de Boer, I. H.; Folsom, A. R.; Psaty, B. M.; Koenig, W.; Meisinger, C.; Peters, A.; Verschuren, W. M M; Bueno-de-Mesquita, H. B.; Blokstra, A.; Rosengren, A.; Wilhelmsen, L.; Lappas, G.; Kuller, L. H.; Grandits, G.; Cooper, J. A.; Bauer, K. A.; Davidson, K. W.; Kirkland, S.; Shaffer, J. A.; Shimbo, D.; Kitamura, A.; Iso, H.; Sato, S.; Dullaart, R. P F; Bakker, S. J L; Gansevoort, R. T.; Ducimetiere, P.; Amouyel, P.; Arveiler, D.; Evans, A.; Ferrières, J.; Schulte, H.; Assmann, G.; Jukema, J. W.; Westendorp, R. G J; Sattar, N.; Cantin, B.; Lamarche, B.; Després, J. P.; Wingard, D. L.; Daniels, L. B.; Gudnason, V.; Aspelund, T.; Trevisan, M.; Hofman, A.; Franco, O. H.; Tunstall-Pedoe, H.; Tavendale, R.; Lowe, G. D O; Woodward, M.; Howard, W. J.; Howard, B. V.; Zhang, Y.; Best, L. G.; Umans, J.; Ben-Shlomo, Y.; Davey-Smith, G.; Onat, A.; Nakagawa, H.; Sakurai, M.; Nakamura, K.; Morikawa, Y.; Njølstad, I.; Mathiesen, E. B.; Wilsgaard, T.; Sundström, J.; Gaziano, J. M.; Ridker, P. M.; Marmot, M.; Clarke, R.; Collins, R.; Fletcher, A.; Brunner, E.; Shipley, M.; Kivimaki, M.; Ridker, P. M.; Buring, J.; Rifai, N.; Cook, N.; Ford, I.; Robertson, M.; Marín Ibañez, A.; Feskens, E. J M; Geleijnse, J. M.
2015-01-01
Motivation: Discrimination statistics describe the ability of a survival model to assign higher risks to individuals who experience earlier events: examples are Harrell's C-index and Royston and Sauerbrei's D, which we call the D-index. Prognostic covariates whose distributions are controlled by the
Eddy Covariance Measurements of the Sea-Spray Aerosol Flu
Brooks, I. M.; Norris, S. J.; Yelland, M. J.; Pascal, R. W.; Prytherch, J.
2015-12-01
Historically, almost all estimates of the sea-spray aerosol source flux have been inferred through various indirect methods. Direct estimates via eddy covariance have been attempted by only a handful of studies, most of which measured only the total number flux, or achieved rather coarse size segregation. Applying eddy covariance to the measurement of sea-spray fluxes is challenging: most instrumentation must be located in a laboratory space requiring long sample lines to an inlet collocated with a sonic anemometer; however, larger particles are easily lost to the walls of the sample line. Marine particle concentrations are generally low, requiring a high sample volume to achieve adequate statistics. The highly hygroscopic nature of sea salt means particles change size rapidly with fluctuations in relative humidity; this introduces an apparent bias in flux measurements if particles are sized at ambient humidity. The Compact Lightweight Aerosol Spectrometer Probe (CLASP) was developed specifically to make high rate measurements of aerosol size distributions for use in eddy covariance measurements, and the instrument and data processing and analysis techniques have been refined over the course of several projects. Here we will review some of the issues and limitations related to making eddy covariance measurements of the sea spray source flux over the open ocean, summarise some key results from the last decade, and present new results from a 3-year long ship-based measurement campaign as part of the WAGES project. Finally we will consider requirements for future progress.
On a new normalization for tractor covariant derivatives
Hammerl, Matthias; Soucek, Vladimir; Silhan, Josef
2010-01-01
A regular normal parabolic geometry of type $G/P$ on a manifold $M$ gives rise to sequences $D_i$ of invariant differential operators, known as the curved version of the BGG resolution. These sequences are constructed from the normal covariant derivative $\
A Superfield Formalism of osp(1,2) Covariant Quantization
Lavrov, P M
2001-01-01
We propose a superfield description of osp(1,2) covariant quantization by extending the set of admissibility conditions for the quantum action. We realize a superfield form of the generating equations, specify the vacuum functional and obtain the corresponding transformations of extended BRST symmetry.
Covariation of Color and Luminance Facilitate Object Individuation in Infancy
Woods, Rebecca J.; Wilcox, Teresa
2010-01-01
The ability to individuate objects is one of our most fundamental cognitive capacities. Recent research has revealed that when objects vary in color or luminance alone, infants fail to individuate those objects until 11.5 months. However, color and luminance frequently covary in the natural environment, thus providing a more salient and reliable…
Detection of fungal damaged popcorn using image property covariance features
Covariance-matrix-based features were applied to the detection of popcorn infected by a fungus that cause a symptom called “blue-eye.” This infection of popcorn kernels causes economic losses because of their poor appearance and the frequently disagreeable flavor of the popped kernels. Images of ker...
Eddy covariance based methane flux in Sundarbans mangroves, India
Jha, Chandra Shekhar; Rodda, Suraj Reddy; Thumaty, Kiran Chand; Raha, A. K.; Dadhwal, V. K.
2014-06-01
We report the initial results of the methane flux measured using eddy covariance method during summer months from the world's largest mangrove ecosystem, Sundarbans of India. Mangrove ecosystems are known sources for methane (CH4) having very high global warming potential. In order to quantify the methane flux in mangroves, an eddy covariance flux tower was recently erected in the largest unpolluted and undisturbed mangrove ecosystem in Sundarbans (India). The tower is equipped with eddy covariance flux tower instruments to continuously measure methane fluxes besides the mass and energy fluxes. This paper presents the preliminary results of methane flux variations during summer months (i.e., April and May 2012) in Sundarbans mangrove ecosystem. The mean concentrations of CH4 emission over the study period was 1682 ± 956 ppb. The measured CH4 fluxes computed from eddy covariance technique showed that the study area acts as a net source for CH4 with daily mean flux of 150.22 ± 248.87 mg m-2 day-1. The methane emission as well as its flux showed very high variability diurnally. Though the environmental conditions controlling methane emission is not yet fully understood, an attempt has been made in the present study to analyse the relationships of methane efflux with tidal activity. This present study is part of Indian Space Research Organisation-Geosphere Biosphere Program (ISRO-GBP) initiative under `National Carbon Project'.
A Superdimensional Dual-covariant Approach to Unified Field Theory
Derbenev, Yaroslav
2013-01-01
An approach to a Unified Field Theory (UFT) is developed as an attempt to establish unification of the Theory of Quantum Fields (QFT) and General Theory of Relativity (GTR) on the background of a covariant differential calculus. A dual State Vector field (DSV)consisting of covariant and contravariant N-component functions of variables of a N-dimensional unified manifod (UM)is introduced to represents matter. DSV is supposed to transform in a way distinct from that of the differentials of the UM variables. Consequently, the hybrid tensors and a hybrid affine tensor (Dynamic Connection, DC) are introduced. The hybrid curvature form (HCF) is introduced as a covariant derivative of DC. A system of covariant Euler-Lagrange (EL) equations for DSV, DC, and a twin couple of the triadic hybrid tensors (Split Metric, SM)is derived. A scalar Lagrangian form is composed based on a set of principles suited for UFT, including the homogeneity in the UM space, differential irreducibility and scale invariance. The type of the...
The QCD evolution of TMD in the covariant approach
Efremov, A. V.; Teryaev, O. V.; Zavada, P.
2016-02-01
The procedure for calculation of the QCD evolution of transverse momentum dependent distributions within the covariant approach is suggested. The standard collinear QCD evolution together with the requirements of relativistic invariance and rotational symmetry of the nucleon in its rest frame represent the basic ingredients of our approach. The obtained results are compared with the predictions of some other approaches.
The QCD evolution of TMD in the covariant approach
Efremov, A V; Zavada, P
2015-01-01
The procedure for calculation of the QCD evolution of transverse momentum dependent distributions within the covariant approach is suggested. The standard collinear QCD evolution together with the requirements of relativistic invariance and rotational symmetry of the nucleon in its rest frame represent the basic ingredients of our approach. The obtained results are compared with the predictions of some other approaches.
[Covariance structure analysis of pharmacists' attitudes toward medication history].
Sato, Hirotaka; Shimamori, Yoshimitu
2011-01-01
Keeping track of patients' medication histories is an important component of pharmacy practice. In this study, we conducted a questionnaire survey on medication histories among pharmacists and performed covariance structure analysis to investigate pharmacists' attitudes toward medication histories. The survey was conducted among pharmacists who work at pharmacies. With regard to the questions on medication histories, factor analysis and covariance structure analysis were performed to create a path diagram. The response rate to the questionnaire was 97.0%. The factor analysis revealed six factors, including: "patient assessment", "learning attitude", "practicing the recording of medication histories", "conscious effort to improve medication histories", "uniformity in medication histories" and "issues regarding medication histories". Meanwhile, covariance structure analysis revealed that the five-factor model excluding "issues regarding medication histories" was the best-fitted model. According to this model, it was clear that the pharmacists were extremely conscious about introducing improvements to the content of medication histories. In this study, covariance structure analysis enabled the effective analysis of the attitudes of pharmacists toward medication histories. We believe that creating and conducting a training program to clarify and resolve issues related to medication histories and then reviewing the outcome of such a training program will lead to quality improvement and standardization of the future management of medication histories. PMID:21532278
Bayesian tests on components of the compound symmetry covariance matrix
Mulder, Joris; Fox, Jean-Paul
2013-01-01
Complex dependency structures are often conditionally modeled, where random effects parameters are used to specify the natural heterogeneity in the population. When interest is focused on the dependency structure, inferences can be made from a complex covariance matrix using a marginal modeling appr
Comparing fixed effects and covariance structure estimators for panel data
DEFF Research Database (Denmark)
Ejrnæs, Mette; Holm, Anders
2006-01-01
In this article, the authors compare the traditional econometric fixed effect estimator with the maximum likelihood estimator implied by covariance structure models for panel data. Their findings are that the maximum like lipoid estimator is remarkably robust to certain types of misspecifications...
Source Coding in Networks with Covariance Distortion Constraints
DEFF Research Database (Denmark)
Zahedi, Adel; Østergaard, Jan; Jensen, Søren Holdt;
2016-01-01
We consider a source coding problem with a network scenario in mind, and formulate it as a remote vector Gaussian Wyner-Ziv problem under covariance matrix distortions. We define a notion of minimum for two positive-definite matrices based on which we derive an explicit formula for the rate...
Distributed Remote Vector Gaussian Source Coding with Covariance Distortion Constraints
DEFF Research Database (Denmark)
Zahedi, Adel; Østergaard, Jan; Jensen, Søren Holdt;
2014-01-01
In this paper, we consider a distributed remote source coding problem, where a sequence of observations of source vectors is available at the encoder. The problem is to specify the optimal rate for encoding the observations subject to a covariance matrix distortion constraint and in the presence...
Altered Cerebral Blood Flow Covariance Network in Schizophrenia.
Liu, Feng; Zhuo, Chuanjun; Yu, Chunshui
2016-01-01
Many studies have shown abnormal cerebral blood flow (CBF) in schizophrenia; however, it remains unclear how topological properties of CBF network are altered in this disorder. Here, arterial spin labeling (ASL) MRI was employed to measure resting-state CBF in 96 schizophrenia patients and 91 healthy controls. CBF covariance network of each group was constructed by calculating across-subject CBF covariance between 90 brain regions. Graph theory was used to compare intergroup differences in global and nodal topological measures of the network. Both schizophrenia patients and healthy controls had small-world topology in CBF covariance networks, implying an optimal balance between functional segregation and integration. Compared with healthy controls, schizophrenia patients showed reduced small-worldness, normalized clustering coefficient and local efficiency of the network, suggesting a shift toward randomized network topology in schizophrenia. Furthermore, schizophrenia patients exhibited altered nodal centrality in the perceptual-, affective-, language-, and spatial-related regions, indicating functional disturbance of these systems in schizophrenia. This study demonstrated for the first time that schizophrenia patients have disrupted topological properties in CBF covariance network, which provides a new perspective (efficiency of blood flow distribution between brain regions) for understanding neural mechanisms of schizophrenia.
Flowing on Riemannian manifold: domain adaptation by shifting covariance.
Cui, Zhen; Li, Wen; Xu, Dong; Shan, Shiguang; Chen, Xilin; Li, Xuelong
2014-12-01
Domain adaptation has shown promising results in computer vision applications. In this paper, we propose a new unsupervised domain adaptation method called domain adaptation by shifting covariance (DASC) for object recognition without requiring any labeled samples from the target domain. By characterizing samples from each domain as one covariance matrix, the source and target domain are represented into two distinct points residing on a Riemannian manifold. Along the geodesic constructed from the two points, we then interpolate some intermediate points (i.e., covariance matrices), which are used to bridge the two domains. By utilizing the principal components of each covariance matrix, samples from each domain are further projected into intermediate feature spaces, which finally leads to domain-invariant features after the concatenation of these features from intermediate points. In the multiple source domain adaptation task, we also need to effectively integrate different types of features between each pair of source and target domains. We additionally propose an SVM based method to simultaneously learn the optimal target classifier as well as the optimal weights for different source domains. Extensive experiments demonstrate the effectiveness of our method for both single source and multiple source domain adaptation tasks.
Positive Semidefinite Integrated Covariance Estimation, Factorizations and Asynchronicity
DEFF Research Database (Denmark)
Boudt, Kris; Laurent, Sébastien; Lunde, Asger;
An estimator of the ex-post covariation of log-prices under asynchronicity and microstructure noise is proposed. It uses the Cholesky factorization on the correlation matrix in order to exploit the heterogeneity in trading intensity to estimate the different parameters sequentially with as many...
FLUXPART: An FOSS solution for Eddy covariance flux partitioning
We report on efforts to develop a FOSS solution for a particular geoscience application. Eddy covariance (EC) instruments are routinely used to measure field-scale evapotranspiration and CO2 fluxes. For many applications, it is desirable to partition the measured evapotranspiration flux into its c...
Determining the oxygen isotope composition of evapotranspiration with eddy covariance
The oxygen isotope componsition of evapotranspiration (dF) represents an important tracer in the study of biosphere-atmosphere interactions, hydrology, paleoclimate, and carbon cycling. Here we demonstrate direct measurement of dF based on eddy covariance (EC) and tunable diode laser (EC-TDL) techni...
Treatment decisions based on scalar and functional baseline covariates.
Ciarleglio, Adam; Petkova, Eva; Ogden, R Todd; Tarpey, Thaddeus
2015-12-01
The amount and complexity of patient-level data being collected in randomized-controlled trials offer both opportunities and challenges for developing personalized rules for assigning treatment for a given disease or ailment. For example, trials examining treatments for major depressive disorder are not only collecting typical baseline data such as age, gender, or scores on various tests, but also data that measure the structure and function of the brain such as images from magnetic resonance imaging (MRI), functional MRI (fMRI), or electroencephalography (EEG). These latter types of data have an inherent structure and may be considered as functional data. We propose an approach that uses baseline covariates, both scalars and functions, to aid in the selection of an optimal treatment. In addition to providing information on which treatment should be selected for a new patient, the estimated regime has the potential to provide insight into the relationship between treatment response and the set of baseline covariates. Our approach can be viewed as an extension of "advantage learning" to include both scalar and functional covariates. We describe our method and how to implement it using existing software. Empirical performance of our method is evaluated with simulated data in a variety of settings and also applied to data arising from a study of patients with major depressive disorder from whom baseline scalar covariates as well as functional data from EEG are available.
On spectral distribution of high dimensional covariation matrices
DEFF Research Database (Denmark)
Heinrich, Claudio; Podolskij, Mark
In this paper we present the asymptotic theory for spectral distributions of high dimensional covariation matrices of Brownian diffusions. More specifically, we consider N-dimensional Itô integrals with time varying matrix-valued integrands. We observe n equidistant high frequency data points...
La Medialuna: un edificio para Chile/The Crescent, a building for Chile
Directory of Open Access Journals (Sweden)
Moreira Recchione, Alberto
2007-12-01
Full Text Available Se refiere los antecedentes históricos sobre la escuela ecuestre de la jineta y su introducción en las faenas agrícola-ganaderas chilenas. Se reseña el nacimiento del rodeo como deporte nacional chileno y los requerimientos del complejo espacio de la “fiesta del rodeo”: un problema arquitectónico y también urbanístico./ The equestrian school of "La Jineta" in Chile, and the architecture for the national holiday of "rodeo."
Directory of Open Access Journals (Sweden)
María Angélica Larraín
2012-11-01
Full Text Available Mussels are one of the most cultivated and commercialized bivalves worldwide and in southern Chile its culture represent an important economic activity. The species identification within the Mytilus genera, by morphological features, is unreliable, so we used a polymorphism RFLP in the gene encoding the polyphenolic adhesive protein as a species-specific genetic marker to describe Mytilus species diversity in southern Chile, and evaluate possible applications in traceability, food quality and safety. Using Me 15-16 marker most mussels were M. chilensis, finding no other pure individuals; however, putative hybrids of M. chilensis x M. trossulus and M. chilensis x M. galloprovincialis were detected. There was no evidence of M. edulis. The presence of the M. trossulus allele, faraway from its distribution area, demands further analysis with different genetic markers to allow a better understanding of its origin. In addition, the correspondence between markers that distinguishes northern from southern hemisphere M. galloprovincialis, with those who discriminates between M. chilensis and M. galloprovincialis would contribute to the taxonomic status of Chilean blue mussels. In Chile, the genetic composition of Mytilus indicates that geographical origin of mussels and its traceability cannot be established merely from the identification of the species. The use of other markers would be required.Los mejillones son una de las especies de bivalvos más cultivadas y comercializadas, en el sur de Chile donde su cultivo representa una actividad económica importante. La identificación de la especie dentro del género Mytilus, basada en las características morfológicas no es confiable por lo que se utilizó un polimorfismo RFLP en el gen que codifica la proteína adhesiva polifenólica como marcador genético específico de la especie para describir la diversidad de especies Mytilus en el sur de Chile, y evaluar posibles aplicaciones en trazabilidad
Assessing spatial covariance among time series of abundance.
Jorgensen, Jeffrey C; Ward, Eric J; Scheuerell, Mark D; Zabel, Richard W
2016-04-01
For species of conservation concern, an essential part of the recovery planning process is identifying discrete population units and their location with respect to one another. A common feature among geographically proximate populations is that the number of organisms tends to covary through time as a consequence of similar responses to exogenous influences. In turn, high covariation among populations can threaten the persistence of the larger metapopulation. Historically, explorations of the covariance in population size of species with many (>10) time series have been computationally difficult. Here, we illustrate how dynamic factor analysis (DFA) can be used to characterize diversity among time series of population abundances and the degree to which all populations can be represented by a few common signals. Our application focuses on anadromous Chinook salmon (Oncorhynchus tshawytscha), a species listed under the US Endangered Species Act, that is impacted by a variety of natural and anthropogenic factors. Specifically, we fit DFA models to 24 time series of population abundance and used model selection to identify the minimum number of latent variables that explained the most temporal variation after accounting for the effects of environmental covariates. We found support for grouping the time series according to 5 common latent variables. The top model included two covariates: the Pacific Decadal Oscillation in spring and summer. The assignment of populations to the latent variables matched the currently established population structure at a broad spatial scale. At a finer scale, there was more population grouping complexity. Some relatively distant populations were grouped together, and some relatively close populations - considered to be more aligned with each other - were more associated with populations further away. These coarse- and fine-grained examinations of spatial structure are important because they reveal different structural patterns not evident
Assessing spatial covariance among time series of abundance.
Jorgensen, Jeffrey C; Ward, Eric J; Scheuerell, Mark D; Zabel, Richard W
2016-04-01
For species of conservation concern, an essential part of the recovery planning process is identifying discrete population units and their location with respect to one another. A common feature among geographically proximate populations is that the number of organisms tends to covary through time as a consequence of similar responses to exogenous influences. In turn, high covariation among populations can threaten the persistence of the larger metapopulation. Historically, explorations of the covariance in population size of species with many (>10) time series have been computationally difficult. Here, we illustrate how dynamic factor analysis (DFA) can be used to characterize diversity among time series of population abundances and the degree to which all populations can be represented by a few common signals. Our application focuses on anadromous Chinook salmon (Oncorhynchus tshawytscha), a species listed under the US Endangered Species Act, that is impacted by a variety of natural and anthropogenic factors. Specifically, we fit DFA models to 24 time series of population abundance and used model selection to identify the minimum number of latent variables that explained the most temporal variation after accounting for the effects of environmental covariates. We found support for grouping the time series according to 5 common latent variables. The top model included two covariates: the Pacific Decadal Oscillation in spring and summer. The assignment of populations to the latent variables matched the currently established population structure at a broad spatial scale. At a finer scale, there was more population grouping complexity. Some relatively distant populations were grouped together, and some relatively close populations - considered to be more aligned with each other - were more associated with populations further away. These coarse- and fine-grained examinations of spatial structure are important because they reveal different structural patterns not evident
Residual noise covariance for Planck low-resolution data analysis
Keskitalo, R.; Ashdown, M. A. J.; Cabella, P.; Kisner, T.; Poutanen, T.; Stompor, R.; Bartlett, J. G.; Borrill, J.; Cantalupo, C.; de Gasperis, G.; de Rosa, A.; de Troia, G.; Eriksen, H. K.; Finelli, F.; Górski, K. M.; Gruppuso, A.; Hivon, E.; Jaffe, A.; Keihänen, E.; Kurki-Suonio, H.; Lawrence, C. R.; Natoli, P.; Paci, F.; Polenta, G.; Rocha, G.
2010-11-01
Aims: We develop and validate tools for estimating residual noise covariance in Planck frequency maps, we also quantify signal error effects and compare different techniques to produce low-resolution maps. Methods: We derived analytical estimates of covariance of the residual noise contained in low-resolution maps produced using a number of mapmaking approaches. We tested these analytical predictions using both Monte Carlo simulations and by applying them to angular power spectrum estimation. We used simulations to quantify the level of signal errors incurred in the different resolution downgrading schemes considered in this work. Results: We find excellent agreement between the optimal residual noise covariance matrices and Monte Carlo noise maps. For destriping mapmakers, the extent of agreement is dictated by the knee frequency of the correlated noise component and the chosen baseline offset length. Signal striping is shown to be insignificant when properly dealt with. In map resolution downgrading, we find that a carefully selected window function is required to reduce aliasing to the subpercent level at multipoles, ℓ > 2Nside, where Nside is the HEALPix resolution parameter. We show that, for a polarization measurement, reliable characterization of the residual noise is required to draw reliable constraints on large-scale anisotropy. Conclusions: Methods presented and tested in this paper allow for production of low-resolution maps with both controlled sky signal error level and a reliable estimate of covariance of the residual noise. We have also presented a method for smoothing the residual noise covariance matrices to describe the noise correlations in smoothed, bandwidth-limited maps.
Taxonomic status of the roses (Rosa) described by S.G. Dimitrov from Bulgaria
DEFF Research Database (Denmark)
Zielinski, J.; Petrova, A; Tan, Kit
2004-01-01
The original herbarium vouchers for six species of Rosa (Rosaceae) described by S. G. Dimitrov from Bulgaria are taxonomically evaluated. Two species (R. balcanica, R. orphei) are considered hybrids, four other names (R. bulgarica, R. parilica, R. pontica and R. rhodopaea) are taxonomic synonyms...
NODC Standard Product: NODC Taxonomic Code on CD-ROM (NODC Accession 0050418)
National Oceanic and Atmospheric Administration, Department of Commerce — The content of the NODC Taxonomic Code, Version 8 CD-ROM (CD-ROM NODC-68) distributed by NODC is archived in this accession. Version 7 of the NODC Taxonomic Code...
ALMA communication backbone in Chile goes optical
Filippi, G.; Ibsen, J.; Jaque, Sandra; Liello, F.; Navarro, C.
2014-07-01
High-bandwidth communication has become a key factor for scientific installations as Observatories. This paper describes the technical, organizational, and operational goals and the level of completion of the ALMA Optical Link Project. The project focus is the creation and operation of an effective and sustainable communication infrastructure to connect the ALMA Observatory, located in the Atacama Desert, in the Northern region of Chile, with the point of presence in ANTOFAGASTA, about 400km away, of the EVALSO infrastructure, and from there to the Central Office in the Chilean capital, Santiago. This new infrastructure that will be operated in behalf of ALMA by REUNA, the Chilean National Research and Education Network, will use state of the art technologies, like dark fiber from newly built cables and DWDM transmission, allowing extending the reach of high capacity communication to the remote region where the Observatory is located. When completed, the end-to-end Gigabit-per-second (Gbps) capable link will provide ALMA with a modern, effective, robust, communication infrastructure capable to cope with present and future demands, like those coming from fast growing data transfer to rapid response mode, from remote monitoring and engineering to virtual presence.
Macroeconomic fluctuations and bank behavior in Chile
Directory of Open Access Journals (Sweden)
Jorge E. Restrepo
2008-03-01
Full Text Available The purpose of this study is to analyze bank behavior in Chile over time, looking at how their balance sheets and performance move both in the short and long run, and how they react to macroeconomic shocks. The evolution of banking aggregates over an 18 year period (1989-2006, using quarterly data is examined. Techniques common in the real business cycle literature are applied to establish empirical patterns. Robustness tests using several filters are performed. The effects of macro shocks on banking variables are analyzed, both by means of an event study, and by estimating impulse responses with VARs. The results show that credit lags the cycle, demand deposits lead it, both being procyclical, while the capital adequacy ratio (CAR is countercyclical. In addition, a shock to interest rates reduces loans (total, commercial, consumption, and increases non performing loans (NPL and the capital adequacy ratio (CAR. A shock to GDP growth has a positive effect on loans, return over equity (ROE, and a negative impact on NPL and CAR.
[Nutritive value of shellfish consumed in Chile].
Pak, N; Vera, G; Araya, H
1985-03-01
The purpose of the present study was to determine the protein quality and digestibility of shellfish commonly consumed in Chile, and to estimate its contribution to the protein needs of the Chilean population. The shellfish studied were chorito (Mytilus edulis chilensis), macha (Mesodesma donacium), loco (Concholepas concholepas), cholga (Aulacomya ater), erizo (Loxechinus albus) and almeja (no specific variety). The NPU method was used to determine protein quality. The percentage of protein adequacy for adult rations was calculated according to FAO/WHO 1973. The contribution of shellfish to the protein availability according to the family income of the Santiago population, was also calculated. Most of the shellfish presented NPU values of about 70; the lowest values were found for loco (54.9) and macha (63.3). The apparent and true digestibility gave an average of 83.6 and 90.4, respectively. The percentage of protein adequacy of habitual rations ranged between 27% (erizo) and 58% (loco). The availability of shellfish protein in relation to total protein increased from 0.4 to 2.5% when income increased. It is concluded therefore, that shellfish protein is, in general, of good quality. Nevertheless, it might be considered of poor influence insofar as fulfilling the protein needs of the population studied, whatever its socioeconomic level. PMID:3834878
Social Networks and Political Parties in Chile
Directory of Open Access Journals (Sweden)
Adler Lomnitz, Larissa
2002-09-01
Full Text Available This paper describes the origin and evolution of two Chilean political parties (the Radical Party and the Christian Democrat Party through the analysis of the social networks that originated and composed them. The aim of this study is to propose a model of national political cultures on the basis of the structure of social networks related to power and of the symbol system, which legitimizes it. The structure of social networks, horizontal and vertical, are based on reciprocal or redistributive forms of exchange, on what is being exchanged and on the articulation between networks. In every society there are symmetrical and asymmetrical exchanges, which produce horizontal and vertical networks. These networks interact among themselves to form the social fabric. The dominance of some over others and how they combine, delineate the character of the political culture (authoritarian vs. egalitarian. Chile is a multiparty country within which there are cohorts of horizontal groups of friends, who informally exercise a central control over their members and create invisible boundaries setting them apart from others, in which leadership is under constrains. The result is both a strong presidential system based on an almost fanatic legitimacy, combined with factionalism and a strong parliamentary system.
[Nutritive value of shellfish consumed in Chile].
Pak, N; Vera, G; Araya, H
1985-03-01
The purpose of the present study was to determine the protein quality and digestibility of shellfish commonly consumed in Chile, and to estimate its contribution to the protein needs of the Chilean population. The shellfish studied were chorito (Mytilus edulis chilensis), macha (Mesodesma donacium), loco (Concholepas concholepas), cholga (Aulacomya ater), erizo (Loxechinus albus) and almeja (no specific variety). The NPU method was used to determine protein quality. The percentage of protein adequacy for adult rations was calculated according to FAO/WHO 1973. The contribution of shellfish to the protein availability according to the family income of the Santiago population, was also calculated. Most of the shellfish presented NPU values of about 70; the lowest values were found for loco (54.9) and macha (63.3). The apparent and true digestibility gave an average of 83.6 and 90.4, respectively. The percentage of protein adequacy of habitual rations ranged between 27% (erizo) and 58% (loco). The availability of shellfish protein in relation to total protein increased from 0.4 to 2.5% when income increased. It is concluded therefore, that shellfish protein is, in general, of good quality. Nevertheless, it might be considered of poor influence insofar as fulfilling the protein needs of the population studied, whatever its socioeconomic level.
Lompay, Robert R.; Petrov, Alexander N.
2013-10-01
The present paper continues the work of Lompay and Petrov [J. Math. Phys. 54, 062504 (2013)] where manifestly covariant differential identities and conserved quantities in generally covariant metric-torsion theories of gravity of the most general type have been constructed. Here, we study these theories presented more concretely, setting that their Lagrangians {L} are manifestly generally covariant scalars: algebraic functions of contractions of tensor functions and their covariant derivatives. It is assumed that Lagrangians depend on metric tensor g, curvature tensor R, torsion tensor T and its first {{nabla }}{T} and second {{nabla }}{{nabla }}{T} covariant derivatives, besides, on an arbitrary set of other tensor (matter) fields {\\varphi } and their first {{nabla }}{\\varphi } and second {{nabla }}{{nabla }}{\\varphi } covariant derivatives: {L}= {L}({g},{R}; {T},{{nabla }}{T},{{nabla }}{{nabla }}{T}; {\\varphi },{{nabla }}{\\varphi },{{nabla }}{{nabla }}{\\varphi }). Thus, both the standard minimal coupling with the Riemann-Cartan geometry and non-minimal coupling with the curvature and torsion tensors are considered. The studies and results are as follow: (a) A physical interpretation of the Noether and Klein identities is examined. It was found that they are the basis for constructing equations of balance of energy-momentum tensors of various types (canonical, metrical, and Belinfante symmetrized). The equations of balance are presented. (b) Using the generalized equations of balance, new (generalized) manifestly generally covariant expressions for canonical energy-momentum and spin tensors of the matter fields are constructed. In the cases, when the matter Lagrangian contains both the higher derivatives and non-minimal coupling with curvature and torsion, such generalizations are non-trivial. (c) The Belinfante procedure is generalized for an arbitrary Riemann-Cartan space. (d) A more convenient in applications generalized expression for the canonical
Si, Xingfeng; Baselga, Andrés; Leprieur, Fabien; Song, Xiao; Ding, Ping
2016-03-01
Taxonomic diversity considers all species being equally different from each other and thus disregards species' different ecological functions. Exploring taxonomic and functional aspects of biodiversity simultaneously can better understand the processes of community assembly. We analysed taxonomic and functional alpha and beta diversities of breeding bird assemblages on land-bridge islands in the Thousand Island Lake, China. Given the high dispersal ability of most birds at this spatial scale (several kilometres), we predicted (i) selective extinction driving alpha and beta diversities after the creation of land-bridge islands of varying area and (ii) low taxonomic and functional beta diversities that were not correlated to spatial distance. Breeding birds were surveyed on 37 islands annually from 2007 to 2014. We decomposed beta diversity of breeding birds into spatial turnover and nestedness-resultant components, and related taxonomic and functional diversities to island area and isolation using power regression models (for alpha diversity) and multiple regression models on distance matrices (for beta diversity). We then ran simulations to assess the strength of the correlations between taxonomic and functional diversities. Results revealed that both taxonomic and functional alpha diversities increased with island area. The taxonomic nestedness-resultant and turnover components increased and decreased with difference in area, respectively, but functional counterparts did not. Isolation played a minor role in explaining alpha- and beta-diversity patterns. By partitioning beta diversity, we found low levels of overall taxonomic and functional beta diversities. The functional nestedness-resultant component dominated overall functional beta diversity, whereas taxonomic turnover was the dominant component for taxonomic beta diversity. The simulation showed that functional alpha and beta diversities were significantly correlated with taxonomic diversities, and the
Directory of Open Access Journals (Sweden)
Constanza J Letelier
2011-11-01
Full Text Available Se estableció una taxonomía de personas con diabetes tipo 2 basada en sus representaciones de enfermedad. Para ello se realizó un análisis de conglomerados con las respuestas de una muestra de conveniencia de 103 adultos de atención primaria de salud de la zona central de Chile, los que completaron la escala IPQ-R. Este análisis arrojó 3 grupos de pacientes, denominados Preocupado, Desesperanzado y Negador. El primero confía en los procedimientos para atenuar los efectos de la enfermedad. El segundo manifiesta una baja creencia acerca de la posibilidad de controlarla. El tercero no la considera como una enfermedad crónica. Los grupos fueron comparados en respuesta emocional, intención de adherir, percepción de necesidad y preocupación por el tratamiento, para complementar el procedimiento de análisis de conglomerado, utilizando ANOVA o Chi cuadrado. Consistente con sus perfiles, presentan diferencias significativas en sus respuestas emocionales, creencias acerca de los medicamentos, intención de adherir, tiempo de tratamiento, edad y educación. Se discute la utilidad de estas taxonomías para el tratamiento diferencial de los pacientes.A taxonomy of patients with type 2 diabetes based on their illness representations was developed. To do this a cluster analysis was conducted, using the responses of a convenience sample of 103 adults from primary health care in central Chile, who completed the IPQ-R scale. This analysis lead to 3 groups of patients labeled Preoccupied, Hopeless, and Deniers. The first relies on procedures to mitigate the effects of the disease. The second shows a low belief about the possibility to control the disease. The third does not consider diabetes as a chronic disease. The groups were compared on emotional response, intention to adhere, perception of need and concern about the treatment, to complement the cluster analysis procedure, using ANOVA or chi-square. Consistent with their profiles, the groups
[The evolution theory in the medical sciences in Chile].
Cruz-Coke, R
1994-02-01
The evolutionist ideas of Lamarck, Darwin and Haeckel entered the country through the arrival of their books. "On the origin of Species" arrived in Chile in 1869. The most outstanding immigrant european physicians that discussed these ideas were Rodulfo A Phillippi (1808-1904) and Juan José Brunner (1825-1899). Both discussed Darwin's ideas in their books and conferences as academics of the Faculty of Medicine of the University of Chile. The first Chilean physicians that read and discussed the validity of evolution theory were Adolfo Valderrama (1834-1902) and Pedro Candia Salgado. Both wrote articles about this matter in Revista Médica de Chile in 1872 and 1874. The professor of general biology, Juan Noé Crevani, italian physician and zoologist that arrived in Chile in 1912, was the first to teach directly the concepts of the evolution theory until his death in 1947. Professor Noé founded the great biological school of the twentieth century in Chile and his disciples introduced the concepts of Mendelian theory and neodarwinism in the decade of fifties. The theory of evolution was taught as a chapter of general biology in the Faculty of Medicine between 1913 and 1947, but its practical applications to medicine were introduced with the birth of medical genetics in the decade of fifties and the foundation of Chilean Genetics society in 1964, under the direction of professors Danko Brncic and Gustavo Hoecker, both awarded with the National Sciences Prize.
[Mental health in Chile and Finland: Challenges and lessons].
Retamal C, Pedro; Markkula, Niina; Peña, Sebastián
2016-07-01
This article analyses and compares the epidemiology of mental disorders and relevant public policies in Chile and Finland. In Chile, a specific mental health law is still lacking. While both countries highlight the role of primary care, Finland places more emphasis on participation and recovery of service users. Comprehensive mental health policies from Finland, such as a successful suicide prevention program, are presented. Both countries have similar prevalence of mental disorders, high alcohol consumption and high suicide rates. In Chile, the percentage of total disease burden due to psychiatric disorders is 13% and in Finland 14%. However, the resources to address these issues are very different. Finland spends 4.5% of its health budget on mental health, while in Chile the percentage is 2.2%. This results in differences in human resources and service provision. Finland has five times more psychiatric outpatient visits, four times more psychiatrists, triple antidepressant use and twice more clinical guidelines for different psychiatric conditions. In conclusion, both countries have similar challenges but differing realities. This may help to identify gaps and potential solutions for public health challenges in Chile. Finlands experience demonstrates the importance of political will and long-term vision in the construction of mental health policies. PMID:27661557
First record of Phoebis argante chincha Lamas (Lepidoptera, Pieridae) in Chile
Héctor A. Vargas; Gerardo Lamas
2011-01-01
First record of Phoebis argante chincha Lamas (Lepidoptera, Pieridae) in Chile. The presence of Phoebis argante chincha Lamas, 1976 (Lepidoptera, Pieridae) is reported for the first time in Chile, from the Azapa valley, Arica.Primeiro registro de Phoebis argante chincha Lamas (Lepidoptera, Pieridae) no Chile. A presença de Phoebis argante chincha Lamas, 1976 (Lepidoptera; Pieridae) é mencionada pela primeira vez para o Chile, no vale de Azapa, Arica.
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BERNARDO R BROITMAN
2011-03-01
Full Text Available Along the coast of central Chile, geographic trends of diversity have been inferred from literature compilations and museum collections based on species range limits for some taxonomic groups. However, spatially-intensive field-based assessments of macrobenthic species richness are largely missing. Over the course of a multiyear study (1998-2005, we characterized latitudinal patterns of rocky intertidal diversity at 18 sites along the coast of central Chile (29-36° S. At each site, the number of sessile and mobile macrobenthic species was quantified in 0.25 m² quadrats. Two estimators of local (alpha diversity were used: observed local species richness, calculated from the asymptote of a species-rarefaction curve, and the Chao2 index, which takes into account the effect of rare species on estimates of local richness. We identified a total of 71 species belonging to 66 genera for a total of 86 taxa. The most diverse groups were herbivorous mollusks (27 taxa and macroalgae (43 taxa. Diversity showed a complex spatial pattern with areas of high species richness interspersed with areas of low richness. In accordance with previous work, we found no trend in the number of herbivorous mollusks and an inverse and significant latitudinal gradient in the number of algal species. Our results highlight the need for taxonomically diverse assessments of biodiversity of the dominant taxa that conform intertidal communities.A lo largo de la costa de Chile central, los patrones geográficos de diversidad han sido inferidos a partir de revisiones literarias y colecciones de museos para algunos grupos taxonómicos. Sin embargo, aun no contamos con una evaluación integral, y en terreno, de la riqueza de especies macrobentónicas intermareales. En un estudio de largo plazo conducido entre 1998 y 2005 caracterizamos los patrones latitudinales en la biodiversidad del intermareal rocoso en 18 sitios a lo largo de la costa de Chile central (29-36° S. En cada sitio
Gini covariance matrix and its affine equivariant version
Weatherall, Lauren Anne
Gini's mean difference (GMD) and its derivatives such as Gini index have been widely used as alternative measures of variability over one century in many research fields especially in finance, economics and social welfare. In this dissertation, we generalize the univariate GMD to the multivariate case and propose a new covariance matrix so called the Gini covariance matrix (GCM). The extension is natural, which is based on the covariance representation of GMD with the notion of multivariate spatial rank function. In order to gain the affine equivariance property for GCM, we utilize the transformation-retransformation (TR) technique and obtain TR version GCM that turns out to be a symmetrized M-functional. Indeed, both GCMs are symmetrized approaches based on the difference of two independent variables without reference of a location, hence avoiding some arbitrary definition of location for non-symmetric distributions. We study the properties of both GCMs. They possess the so-called independence property, which is highly important, for example, in independent component analysis. Influence functions of two GCMs are derived to assess their robustness. They are found to be more robust than the regular covariance matrix but less robust than Tyler and Dumbgen M-functional. Under elliptical distributions, the relationship between the scatter parameter and the two GCM are obtained. With this relationship, principal component analysis (PCA) based on GCM is possible. Estimation of two GCMs is presented. We study asymptotical behavior of the estimators. √n-consistency and asymptotical normality of estimators are established. Asymptotic relative efficiency (ARE) of TR-GCM estimator with respect to sample covariance matrix is compared to that of Tyler and Dumbgen M-estimators. With little loss on efficiency (gains high efficiency for heavy-tailed distributions. Finite sample behavior of Gini estimators is explored under various models using two criteria. As a by-product, a
77 FR 22663 - Importation of Pomegranates From Chile Under a Systems Approach
2012-04-17
... Chile Under a Systems Approach AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Final... continental United States of pomegranates from Chile, subject to a systems approach. Under this systems... plant protection organization of Chile and certified as having a low prevalence of Brevipalpus...
19 CFR 10.490 - Goods re-entered after repair or alteration in Chile.
2010-04-01
... Chile. 10.490 Section 10.490 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND... States-Chile Free Trade Agreement Goods Returned After Repair Or Alteration § 10.490 Goods re-entered after repair or alteration in Chile. (a) General. This section sets forth the rules which apply...
2012-03-02
... Suggestions for Environmental Cooperation Pursuant to the United States-Chile Environmental Cooperation Agreement ACTION: Notice of preparation of the 2012-2014 U.S.-Chile Environmental Cooperation Work Program... suggestions regarding items for inclusion in a new work program for implementing the U.S.-Chile...
7 CFR 319.56-23 - Apricots, nectarines, peaches, plumcot, and plums from Chile.
2010-01-01
... Chile. 319.56-23 Section 319.56-23 Agriculture Regulations of the Department of Agriculture (Continued... and Vegetables § 319.56-23 Apricots, nectarines, peaches, plumcot, and plums from Chile. (a... from Chile in accordance with this section and all other applicable provisions of this subpart. 3 3...
CHILE: An Evidence-Based Preschool Intervention for Obesity Prevention in Head Start
Davis, Sally M.; Sanders, Sarah G.; FitzGerald, Courtney A.; Keane, Patricia C.; Canaca, Glenda F.; Volker-Rector, Renee
2013-01-01
Background: Obesity is a major concern among American Indians and Hispanics. The Child Health Initiative for Lifelong Eating and Exercise (CHILE) is an evidence-based intervention to prevent obesity in children enrolled in 16 Head Start (HS) Centers in rural communities. The design and implementation of CHILE are described. Methods: CHILE uses a…
77 FR 64106 - Renewable Energy and Energy Efficiency Trade Policy Mission to Chile
2012-10-18
... International Trade Administration Renewable Energy and Energy Efficiency Trade Policy Mission to Chile AGENCY... (RE&EE) Trade Policy Mission to Santiago, Chile from April 15-16, 2013. The mission is designed to be... conducive to growth in Chile's RE&EE market; and (2) introducing U.S. RE&EE exporters to key...
The Unexpected Awakening of Chaitén Volcano, Chile
Carn, Simon A.; Pallister, John S.; Lara, Luis; Ewert, John W.; Watt, Sebastian; Prata, Alfred J.; Thomas, Ronald J.; Villarosa, Gustavo
2009-06-01
On 2 May 2008, a large eruption began unexpectedly at the inconspicuous Chaitén volcano in Chile's southern volcanic zone. Ash columns abruptly jetted from the volcano into the stratosphere, followed by lava dome effusion and continuous low-altitude ash plumes [Lara, 2009]. Apocalyptic photographs of eruption plumes suffused with lightning were circulated globally. Effects of the eruption were extensive. Floods and lahars inundated the town of Chaitén, and its 4625 residents were evacuated. Widespread ashfall and drifting ash clouds closed regional airports and cancelled hundreds of domestic flights in Argentina and Chile and numerous international flights [Guffanti et al., 2008]. Ash heavily affected the aquaculture industry in the nearby Gulf of Corcovado, curtailed ecotourism, and closed regional nature preserves. To better prepare for future eruptions, the Chilean government has boosted support for monitoring and hazard mitigation at Chaitén and at 42 other highly hazardous, active volcanoes in Chile.
Desigualdad GeogrÃ¡fica en Chile
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Claudio A. Agostini
2007-03-01
Full Text Available Despite success in reducing poverty over the last twenty years, inequality in Chile has remained virtually unchanged, making Chile one of the least equal countries in the world. High levels of inequality have been shown to hamper further reductions in poverty as well as economic growth and local inequality has been shown to affect such outcomes as violence and health. The study of inequality at the local level is thus crucial for understanding the economic well-being of a country. Local measures of inequality have been difficult to obtain, but recent theoretical advances have enabled the combination of survey and census data to obtain estimators of inequality that are robust at disaggregated geographic levels. In this paper, we employ this methodology to produce consistent estimators of inequality for every county in Chile. We find a great deal of variation in inequality, with countylevel Gini coefficients ranging from 0.41 to 0.63.
Bootstrap Tests and Confidence Regions for Functions of a Covariance Matrix
Beran, Rudolf; Srivastava, Muni S.
1985-01-01
Bootstrap tests and confidence regions for functions of the population covariance matrix have the desired asymptotic levels, provided model restrictions, such as multiple eigenvalues in the covariance matrix, are taken into account in designing the bootstrap algorithm.
On Two-stage Estimate Based on Independent Estimate of Covariance Matrix
Institute of Scientific and Technical Information of China (English)
Su Ju YIN; Song Gui WANG
2006-01-01
When an independent estimate of covariance matrix is available, we often prefer two-stage estimate (TSE). Expressions of exact covariance matrix of the TSE obtained by using all and some covariables in covariance adjustment approach are given, and a necessary and sufficient condition for the TSE to be superior to the least square estimate and related large sample test is also established.Furthermore the TSE, by using some covariables, is expressed as weighted least square estimate. Basing on this fact, a necessary and sufficient condition for the TSE by using some covariables to be superior to the TSE by using all covariables is obtained. These results give us some insight into the selection of covariables in the TSE and its application.
The Shape of Covariantly Smeared Sources in Lattice QCD
von Hippel, Georg M; Rae, Thomas D; Wittig, Hartmut
2013-01-01
Covariantly smeared sources are commonly used in lattice QCD to enhance the projection onto the ground state. Here we investigate the dependence of their shape on the gauge field background and find that the presence of localized concentrations of magnetic field can lead to strong distortions which reduce the smearing radii achievable by iterative smearing prescriptions. In particular, as $a\\to 0$, iterative procedures like Jacobi smearing require increasingly large iteration counts in order to reach physically-sized smearing radii $r_{sm}\\sim$ 0.5 fm, and the resulting sources are strongly distorted. To bypass this issue, we propose a covariant smearing procedure (``free-form smearing'') that allows us to create arbitrarily shaped sources, including in particular Gaussians of arbitrary radius.
Modeling corporate defaults: Poisson autoregressions with exogenous covariates (PARX)
DEFF Research Database (Denmark)
Agosto, Arianna; Cavaliere, Guiseppe; Kristensen, Dennis;
We develop a class of Poisson autoregressive models with additional covariates (PARX) that can be used to model and forecast time series of counts. We establish the time series properties of the models, including conditions for stationarity and existence of moments. These results are in turn used...... in the analysis of the asympotic properties of the maximum-likelihood estimators of the models. The PARX class of models is used to analyse the time series properties of monthly corporate defaults in the US in the period 1982-2011 using financial and economic variables as exogeneous covariates...... years economic and financial factors at the macro level are capable to explain a large portion of the correlation of US firms defaults over time....
Nuclear response theory with multiphonon coupling in a covariant framework
Litvinova, Elena
2014-01-01
Background: Nuclear excited states within a wide range of excitation energies are formally described by the linear response theory. Besides its conventional formulation within the quasiparticle random phase approximation (QRPA) representing excited states as two correlated quasiparticles (2q), there exist extensions for 4q configurations. Such extended approaches are quite successful in the description of gross properties of nuclear spectra, however, accounting for many of their fine features requires further extension of the configuration space. Purpose: This work aims at the development of an approach which is capable of such an extension as well as of reproducing and predicting fine spectral properties, which are of special interest at low energies. Method: The method is based on the covariant density functional theory and time blocking approximation, and it is extended including couplings between quasiparticles and multiphonon excitations. Results: The covariant multiphonon response theory is developed an...
How (not) to teach Lorentz covariance of the Dirac equation
Nikolic, H
2013-01-01
In the textbook proofs of Lorentz covariance of the Dirac equation, one treats the wave function as a spinor and gamma matrices as scalars, leading to a quite complicated formalism with several pedagogic drawbacks. As an alternative, I propose to teach Dirac equation and its Lorentz covariance by using a much simpler, but physically equivalent formalism, in which these drawbacks do not appear. In this alternative formalism, the wave function transforms as a scalar and gamma matrices as components of a vector, such that the standard physically relevant bilinear combinations do not change their transformation properties. The alternative formalism allows also a natural construction of some additional non-standard bilinear combinations with well-defined transformation properties.
Markov modulated Poisson process models incorporating covariates for rainfall intensity.
Thayakaran, R; Ramesh, N I
2013-01-01
Time series of rainfall bucket tip times at the Beaufort Park station, Bracknell, in the UK are modelled by a class of Markov modulated Poisson processes (MMPP) which may be thought of as a generalization of the Poisson process. Our main focus in this paper is to investigate the effects of including covariate information into the MMPP model framework on statistical properties. In particular, we look at three types of time-varying covariates namely temperature, sea level pressure, and relative humidity that are thought to be affecting the rainfall arrival process. Maximum likelihood estimation is used to obtain the parameter estimates, and likelihood ratio tests are employed in model comparison. Simulated data from the fitted model are used to make statistical inferences about the accumulated rainfall in the discrete time interval. Variability of the daily Poisson arrival rates is studied.
Noise Covariance Properties in Dual-Tree Wavelet Decompositions
Chaux, Caroline; Duval, Laurent; 10.1109/TIT.2007.909104
2011-01-01
Dual-tree wavelet decompositions have recently gained much popularity, mainly due to their ability to provide an accurate directional analysis of images combined with a reduced redundancy. When the decomposition of a random process is performed -- which occurs in particular when an additive noise is corrupting the signal to be analyzed -- it is useful to characterize the statistical properties of the dual-tree wavelet coefficients of this process. As dual-tree decompositions constitute overcomplete frame expansions, correlation structures are introduced among the coefficients, even when a white noise is analyzed. In this paper, we show that it is possible to provide an accurate description of the covariance properties of the dual-tree coefficients of a wide-sense stationary process. The expressions of the (cross-)covariance sequences of the coefficients are derived in the one and two-dimensional cases. Asymptotic results are also provided, allowing to predict the behaviour of the second-order moments for larg...
Scale-covariant theory of gravitation and astrophysical applications
Canuto, V.; Adams, P. J.; Hsieh, S.-H.; Tsiang, E.
1977-01-01
A scale-covariant theory of gravitation is presented which is characterized by a set of equations that are complete only after a choice of the scale function is made. Special attention is given to gauge conditions and units which allow gravitational phenomena to be described in atomic units. The generalized gravitational-field equations are derived by performing a direct scale transformation, by extending Riemannian geometry to Weyl geometry through the introduction of the notion of cotensors, and from a variation principle. Modified conservation laws are provided, a set of dynamical equations is obtained, and astrophysical consequences are considered. The theory is applied to examine certain homogeneous cosmological solutions, perihelion shifts, light deflections, secular variations of planetary orbital elements, stellar structure equations for a star in quasi-static equilibrium, and the past thermal history of earth. The possible relation of the scale-covariant theory to gauge field theories and their predictions of cosmological constants is discussed.
Deformed Covariant Quantum Phase Spaces as Hopf Algebroids
Lukierski, Jerzy
2015-01-01
We consider the general D=4 (10+10)-dimensional kappa-deformed quantum phase space as given by Heisenberg double \\mathcal{H} of D=4 kappa-deformed Poincare-Hopf algebra H. The standard (4+4) -dimensional kappa - deformed covariant quantum phase space spanned by kappa - deformed Minkowski coordinates and commuting momenta generators ({x}_{\\mu },{p}_{\\mu }) is obtained as the subalgebra of \\mathcal{H}. We study further the property that Heisenberg double defines particular quantum spaces with Hopf algebroid structure. We calculate by using purely algebraic methods the explicite Hopf algebroid structure of standard kappa - deformed quantum covariant phase space in Majid-Ruegg bicrossproduct basis. The coproducts for Hopf algebroids are not unique, determined modulo the coproduct gauge freedom. Finally we consider the interpretation of the algebraic description of quantum phase spaces as Hopf bialgebroids.
Batalin-Vilkovisky formalism in locally covariant field theory
Rejzner, Katarzyna
2011-01-01
The present work contains a complete formulation of the Batalin-Vilkovisky (BV) formalism in the framework of locally covariant field theory. In the first part of the thesis the classical theory is investigated with a particular focus on the infinite dimensional character of the underlying structures. It is shown that the use of infinite dimensional differential geometry allows for a conceptually clear and elegant formulation. The construction of the BV complex is performed in a fully covariant way and we also generalize the BV framework to a more abstract level, using functors and natural transformations. In this setting we construct the BV complex for classical gravity. This allows us to give a homological interpretation to the notion of diffeomorphism invariant physical quantities in general relativity. The second part of the thesis concerns the quantum theory. We provide a framework for the BV quantization that doesn't rely on the path integral formalism, but is completely formulated within perturbative a...
Taxonomic Significance of ISTR to Discriminate Species in Agavaceae
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Martha I. Torres-Moran
2008-01-01
Full Text Available Family Agavaceae is endemic of American Continent. From the around 300 species recognized in this family, 217 occur in Mexico. Relevant ethnobotanic relationships among Agavaceae and the several native human cultures of the American Continent have been established since prehispanic times. Agave is one of the most important genus in that family due to its great diversity and abundance, mainly in arid and semiarid regions of Mexico. In this country, near to 15 species of Agave are used to elaborate alcoholic beverages. Agave tequilana weber var. azul is indubitable the most important of them because is the raw material to elaborate a particular worldly famous class of mescal, named tequila. Agave salmiana, A. maximiliana and A. durangensis are species less famous than A. tequilana, but they also have a high quality and level of carbohydrates and in fact, support local mescal industries. In these last species several taxonomic controversies exist concerning their specific delimitation. In this study the molecular characterization of eight species of Agavaceae using ISTR was performed in order to determine the significance of these markers for discriminating among specific taxa. The results suggest that these molecular markers are worthy to typify species of Agavaceae and detect intrapopulation variability.
Genetic Variation in Nacobbus aberrans: An Approach toward Taxonomic Resolution.
Ibrahim, S K; Baldwin, J G; Roberts, P A; Hyman, B C
1997-09-01
Biochemical and molecular analyses of genetic variation were evaluated to address the taxonomic status of Nacobbus aberrans. Isolates from Mexico, Peru, and Argentina, cultured on tomato in the greenhouse, were analyzed with respect to isozyme and DNA marker variation. Although acid phosphatase and malate dehydrogenase revealed distinct profiles for each isolate, non-specific esterases revealed possible affinities between the Peruvian isolates and between the isolates from Mexico and Peru. Two of l 0 RAPD primers revealed affinities suggested by esterase profiles. RFLP analysis of the rDNA repeating unit with six restriction enzymes revealed identical cleavage patterns between the Peru isolates and a distinct profile shared by isolates from Mexico and Argentina. Nucleotide sequence analysis of the 5.8S rRNA coding region revealed differences among the four isolates at eight of 157 positions; sequences of the Peruvian isolates differed from each other at only one position, whereas the Mexican and Argentine isolates were identical and could be distinguished from the Peruvian isolates. A distance matrix from unweighted pairwise comparisons of the 5.8S rDNA revealed apparent elevated intraspecific divergence in N. aberrans comparable to intergeneric divergence between Heterodera and Globodera. Analysis of additional N. aberrans isolates from throughout the distribution range should help determine the full extent of intraspecific genetic variation that underlies the phenotypic and morphologic diversity of the genus.