736 resultados para Horne, Lena , 1917-2010, American


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The sol-gel synthesis and characterization of n≥3n≥3 Aurivillius phase thin filmsdeposited on Pt/Ti/SiO2–SiPt/Ti/SiO2–Si substrates is described. The number of perovskite layers, nn, was increased by inserting BiFeO3BiFeO3 into three layered Aurivillius phase Bi4Ti3O12Bi4Ti3O12 to form compounds such as Bi5FeTi3O15Bi5FeTi3O15 (n=4)(n=4). 30% of the Fe3+Fe3+ ions in Bi5FeTi3O15Bi5FeTi3O15 were substituted with Mn3+Mn3+ ions to form the structureBi5Ti3Fe0.7Mn0.3O15Bi5Ti3Fe0.7Mn0.3O15. The electromechanical responses of the materials were investigated using piezoresponse force microscopy and the results are discussed in relation to the crystallinity of the films as measured by x-ray diffraction.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Surveys can collect important data that inform policy decisions and drive social science research. Large government surveys collect information from the U.S. population on a wide range of topics, including demographics, education, employment, and lifestyle. Analysis of survey data presents unique challenges. In particular, one needs to account for missing data, for complex sampling designs, and for measurement error. Conceptually, a survey organization could spend lots of resources getting high-quality responses from a simple random sample, resulting in survey data that are easy to analyze. However, this scenario often is not realistic. To address these practical issues, survey organizations can leverage the information available from other sources of data. For example, in longitudinal studies that suffer from attrition, they can use the information from refreshment samples to correct for potential attrition bias. They can use information from known marginal distributions or survey design to improve inferences. They can use information from gold standard sources to correct for measurement error.

This thesis presents novel approaches to combining information from multiple sources that address the three problems described above.

The first method addresses nonignorable unit nonresponse and attrition in a panel survey with a refreshment sample. Panel surveys typically suffer from attrition, which can lead to biased inference when basing analysis only on cases that complete all waves of the panel. Unfortunately, the panel data alone cannot inform the extent of the bias due to attrition, so analysts must make strong and untestable assumptions about the missing data mechanism. Many panel studies also include refreshment samples, which are data collected from a random sample of new

individuals during some later wave of the panel. Refreshment samples offer information that can be utilized to correct for biases induced by nonignorable attrition while reducing reliance on strong assumptions about the attrition process. To date, these bias correction methods have not dealt with two key practical issues in panel studies: unit nonresponse in the initial wave of the panel and in the

refreshment sample itself. As we illustrate, nonignorable unit nonresponse

can significantly compromise the analyst's ability to use the refreshment samples for attrition bias correction. Thus, it is crucial for analysts to assess how sensitive their inferences---corrected for panel attrition---are to different assumptions about the nature of the unit nonresponse. We present an approach that facilitates such sensitivity analyses, both for suspected nonignorable unit nonresponse

in the initial wave and in the refreshment sample. We illustrate the approach using simulation studies and an analysis of data from the 2007-2008 Associated Press/Yahoo News election panel study.

The second method incorporates informative prior beliefs about

marginal probabilities into Bayesian latent class models for categorical data.

The basic idea is to append synthetic observations to the original data such that

(i) the empirical distributions of the desired margins match those of the prior beliefs, and (ii) the values of the remaining variables are left missing. The degree of prior uncertainty is controlled by the number of augmented records. Posterior inferences can be obtained via typical MCMC algorithms for latent class models, tailored to deal efficiently with the missing values in the concatenated data.

We illustrate the approach using a variety of simulations based on data from the American Community Survey, including an example of how augmented records can be used to fit latent class models to data from stratified samples.

The third method leverages the information from a gold standard survey to model reporting error. Survey data are subject to reporting error when respondents misunderstand the question or accidentally select the wrong response. Sometimes survey respondents knowingly select the wrong response, for example, by reporting a higher level of education than they actually have attained. We present an approach that allows an analyst to model reporting error by incorporating information from a gold standard survey. The analyst can specify various reporting error models and assess how sensitive their conclusions are to different assumptions about the reporting error process. We illustrate the approach using simulations based on data from the 1993 National Survey of College Graduates. We use the method to impute error-corrected educational attainments in the 2010 American Community Survey using the 2010 National Survey of College Graduates as the gold standard survey.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Tutkielmassa tarkastellaan kolmen merimiehen kokemuksia ensimmäisestä merimatkastaan muistitietotutkimuksen ja mikrohistorian avulla. Tutkielman tarkoituksena on tuoda esille se, miten merimiehet ovat kokeneet ja muistaneet ensimmäisen purjehduksensa sekä selvittää sitä, miten merenkulku on kehittynyt 1860-luvulta 1960-luvulle ja miten se on vaikuttanut merenkulkijan arkeen. Carl Julius Panelius (1854-1932) aloitti kajuuttavahtina fregatti Osmolla vuonna 1867, ajankohtana, jolloin Suomi muuttui vähitellen tervaprovinssista merenkulkumaaksi. Matti Lappalainen (1917-2010) pestautui prentiisiksi nelimastoparkki Moshuluun vuonna 1937 ja seilasi viimeisten joukossa Kap Hornin ympäri purjelaivalla. Juhani Heinonen (1948-) teki ensireissunsa M/S Kannaksella jungmannina vuonna 1965, merenkulun jo modernisoituessa. Muistitietoa lähteenä käyttävän tutkimuksen päämääränä on tuoda esiin muistelijoiden omat näkemykset menneisyydestä. Mikrohistoriallinen tutkimustapa taas paneutuu tutkittavaan kohteeseen erityisen tarkasti, jolloin menneisyydestä on mahdollista löytää uusia piirteitä. Mikrohistoriallisen tutkimusotteen myötä muistitietoaineisto nähdään johtolankana menneisyydestä, jolloin tutkijan tulee esittää aineistolle oikeanlaisia kysymyksiä saadakseen menneisyyden jäljet puhumaan. Tutkielmassa on suullisen muistitiedon, haastattelujen, lisäksi käytetty myös kirjoitettuja lähteitä, muistelmia. Tarkoituksena on ollut nostaa merenkulkijan oma ääni esiin ja ymmärtää minkälaista merimiehen arki on laivassa ollut. Tutkielmasta käy ilmi, että vaikka merenkulku on muuttunut tarkasteltavalla ajanjaksolla paljon, ovat kokemukset merimiehenä olemisesta ja ensimmäisestä merimatkasta yllättävän samankaltaisia. Elämä merellä muodostui vahtivuorojen ympärille, johon satamakäynnit tarjosivat odotettua vaihtelua. Muistelijat kertovat hämmästyttävän vähän itse työstä laivalla. Merimiehille erityiset tapahtumat olivat merkityksellisiä, sillä ne poikkesivat laivan tavallisesta arjesta. Merimiesten muistelukerronnasta nousee esiin omakuva ja se millaisia merimiehiä he olivat tai halusivat olla. Yhteistä muistoille on se, että hyvä merimies oli reipas, ahkera eikä ikävöinyt kotiin. Hän teki raskasta työtä, mutta ei valittanut turhasta ja käyttäytyi satamissa sivistyneesti.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

The 2010 Native American Indigenous Studies Conference was held at The Westin La Paloma Resort, Tucson, Arizona, USA from 20-22 May. The conference was scholarly and interdisciplinary and intended for Indigenous and non-Indigenous scholars who work in American Indian/ Native American/ First Nations/ Aboriginal/ Indigenous Studies. The 2010 gathering attracted 768 registrations from the USA, Canada, Hawaii, Mexico, New Zealand and Australia and other countries. This paper is a personal reflection and overview of the 2010 Conference.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

(PDF contains 92 pages.)

Relevância:

40.00% 40.00%

Publicador:

Resumo:

There is abundant empirical evidence on the negative relationship between welfare effort and poverty. However, poverty indicators traditionally used have been representative of the monetary approach, excluding its multidimensional reality from the analysis. Using three regression techniques for the period 1990-2010 and controlling for demographic and cyclical factors, this paper examines the relationship between social spending per capita —as the indicator of welfare effort— and poverty in up to 21 countries of the region. The proportion of the population with an income below its national basic basket of goods and services (PM1) and the proportion of population with an income below 50% of the median income per capita (PM2) were the two poverty indicators considered from the monetarist approach to measure poverty. From the capability approach the proportion of the population with food inadequacy (PC1) and the proportion of the population without access to improved water sources or sanitation facilities (PC2) were used. The fi ndings confi rm that social spending is actually useful to explain changes in poverty (PM1, PC1 and PC2), as there is a high negative and signifi cant correlation between the variables before and after controlling for demographic and cyclical factors. In two regression techniques, social spending per capita did not show a negative relationship with the PM2. Countries with greater welfare effort for the period 1990-2010 were not necessarily those with the lowest level of poverty. Ultimately social spending per capita was more useful to explain changes in poverty from the capability approach.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

We are conducting an ESO Large Program that includes optical photometry, thermal-IR observations, and optical-NIR spectroscopy of selected NEAs. Among the principal goals of the program are shape and spin-state modeling, and searching for YORP-induced changes in rotation periods. One of our targets is asteroid (1917) Cuyo, a near-Earth asteroid from the Amor group. We carried out an extensive observing campaign on Cuyo between April 2010 and April 2013, operating primarily at the ESO 3.6m NTT for optical photometry, and the 8.2m VLT at Paranal for thermal-IR imaging. Further optical observations were acquired at the ESO 2.2m telescope, the Palomar 200" Hale telescope (California), JPL’s Table Mountain Observatory (California) and the Faulkes Telescope South (Australia). We obtained optical imaging data for rotational lightcurves throughout this period, as the asteroid passed through a wide range of observational geometries, conducive to producing a good shape model and spin state solution. The preliminary shape and spin state model indicates a nearly spherical shape and a rotation pole at ecliptic longitude λ = 53° ± 20° and latitude β = -37° ± 10° (1-sigma error bars are approximate). The sidereal rotation period was measured to be 2.6899522 ± (3 × 10^-7) hours. Linkage with earlier lightcurve data shows possible evidence of a small change in rotation rate during the period 1989-2013. We applied the NEATM thermal model (Harris A., Icarus 131, 291, 1998) to our VLT thermal-IR measurements (8-19.6 μm), obtained in September and December 2011. The derived effective diameter ranges from 3.4 to 4.2 km, and the geometric albedo is 0.16 (+0.07, -0.04). Using the shape model and thermal fluxes we will perform a detailed thermophysical analysis using the new Advanced Thermophysical Model (Rozitis, B. & Green, S.F., MNRAS 415, 2042, 2011; Rozitis, B. & Green, S.F., MNRAS 423, 367, 2012). This work was performed in part at the Jet Propulsion Laboratory under a contract with NASA.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Latin-American Society of Forensic Genetics (SLAGF) Interlaboratory Quality Control Exercise (2010-2011) included the analysis of three bloodstain samples in FTA Classic Card (three persons, biologically unrelated) and one theoretical exercise. There were 56 participating laboratories from 13 Latin-American countries that belong to society, were reported 70 STRs, including autosomal and sex chromosome markers with consensus in 53 STRs with a rate in reporting errors of 2.3%. Fifty-six laboratories reported results in theoretical exercise with mistakes in calculation of IP for each marker. It is necessary to hold meetings to discuss the results of this exercise to reach conclusions and recommendations on all aspects of DNA forensics analysis and paternity test, to improve results and quality in the results of each laboratory. © 2011 Elsevier B.V.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

After two decades advertising and defending the synthetic method, João Köpke became active disseminator of analytical method for teaching reading. In five te xts published between 1896 and 1917, produced in different circumstance s for different publics readers, Köpke seeks the support of American and European authors, for their principles as well as for the education experience, to his analytical method. as by theirs principles as by theirs educational experiences. Among those authors: J. Jacotot, A. Bain, A. Meiklejohn, J. Froebel, C. Parker, G. Stanley Hall and J. Chubb. In this article, attention is given to repeated American references with special emphasis on the psychology of Stanley Hall and the method of teaching reading of Meiklejohn, highlighted and placed on convergence by Köpke in his final writings.