876 resultados para Historical research
Resumo:
Dynamic models for electrophoresis are based upon model equations derived from the transport concepts in solution together with user-inputted conditions. They are able to predict theoretically the movement of ions and are as such the most versatile tool to explore the fundamentals of electrokinetic separations. Since its inception three decades ago, the state of dynamic computer simulation software and its use has progressed significantly and Electrophoresis played a pivotal role in that endeavor as a large proportion of the fundamental and application papers were published in this periodical. Software is available that simulates all basic electrophoretic systems, including moving boundary electrophoresis, zone electrophoresis, ITP, IEF and EKC, and their combinations under almost exactly the same conditions used in the laboratory. This has been employed to show the detailed mechanisms of many of the fundamental phenomena that occur in electrophoretic separations. Dynamic electrophoretic simulations are relevant for separations on any scale and instrumental format, including free-fluid preparative, gel, capillary and chip electrophoresis. This review includes a historical overview, a survey of current simulators, simulation examples and a discussion of the applications and achievements of dynamic simulation.
Resumo:
A total of 1,033 head of steers competing in the Iowa State Fair Beef of Merit class from 1975 through 2000 were summarized. Those grading low Choice and higher averaged 55.4 percent, and the average yield grade was 2.44. Due to rule changes over time the quality grade and cutability shifted. In recent years with the emphasis placed on acceptable quality grade and carcass weight, the BOM cattle have improved dramatically in the percent grading Prime and upper Choice. However, with this change has been a reduction in the percent of cattle making yield grade 1 and 2. Growth rate increased through the late 1980s, but has remained static since that time.
Resumo:
Historical, i.e. pre-1957, upper-air data are a valuable source of information on the state of the atmosphere, in some parts of the world dating back to the early 20th century. However, to date, reanalyses have only partially made use of these data, and only of observations made after 1948. Even for the period between 1948 (the starting year of the NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) reanalysis) and the International Geophysical Year in 1957 (the starting year of the ERA-40 reanalysis), when the global upper-air coverage reached more or less its current status, many observations have not yet been digitised. The Comprehensive Historical Upper-Air Network (CHUAN) already compiled a large collection of pre-1957 upper-air data. In the framework of the European project ERA-CLIM (European Reanalysis of Global Climate Observations), significant amounts of additional upper-air data have been catalogued (> 1.3 million station days), imaged (> 200 000 images) and digitised (> 700 000 station days) in order to prepare a new input data set for upcoming reanalyses. The records cover large parts of the globe, focussing on, so far, less well covered regions such as the tropics, the polar regions and the oceans, and on very early upper-air data from Europe and the US. The total number of digitised/inventoried records is 61/101 for moving upper-air data, i.e. data from ships, etc., and 735/1783 for fixed upper-air stations. Here, we give a detailed description of the resulting data set including the metadata and the quality checking procedures applied. The data will be included in the next version of CHUAN. The data are available at doi:10.1594/PANGAEA.821222
Resumo:
Scott DeLancey’s analysis of person-sensitive TAME marking in Lhasa Tibetan – “a.k.a. conjunct-disjunct marking” or “egophoricity” – has stimulated considerable discussion and debate, particularly as previously little-known languages of the Tibeto-Burman area, as well as outside it, have come to be described, and a wider range of functional factors have been taken into account. This chapter is intended as a contribution to this discussion, by presenting the first detailed analysis of person-sensitive TAME marking in a language of the Tani subgroup of Tibeto-Burman, namely Galo. Like Tournadre (2008), I find that person-sensitive TAME marking in Galo is not a grammaticalized index of person (“agreement”) nor of cross-clause subject continuity, but is instead a semantic index of an assertor’s knowledge state. Unlike in more westerly Tibeto-Burman languages, however, different construals of agency and/or volition do not seem to be factors in the Galo system. Thus, there are both similarities and differences underlying systems of person-sensitive TAME marking in different Tibeto-Burman languages; this suggests that further research - particularly, employing a diachronic perspective when possible - will be required before we can confidently characterize person-sensitive TAME marking from a pan-Tibeto-Burman (or broader) cross-linguistic perspective.
Resumo:
Upper-air observations are a fundamental data source for global atmospheric data products, but uncertainties, particularly in the early years, are not well known. Most of the early observations, which have now been digitized, are prone to a large variety of undocumented uncertainties (errors) that need to be quantified, e.g., for their assimilation in reanalysis projects. We apply a novel approach to estimate errors in upper-air temperature, geopotential height, and wind observations from the Comprehensive Historical Upper-Air Network for the time period from 1923 to 1966. We distinguish between random errors, biases, and a term that quantifies the representativity of the observations. The method is based on a comparison of neighboring observations and is hence independent of metadata, making it applicable to a wide scope of observational data sets. The estimated mean random errors for all observations within the study period are 1.5 K for air temperature, 1.3 hPa for pressure, 3.0 ms−1for wind speed, and 21.4° for wind direction. The estimates are compared to results of previous studies and analyzed with respect to their spatial and temporal variability.
Resumo:
Although the literature has provided many critiques of research done on family preservation programs, these critiques have usually been limited to the studies ' assumptions, approach, or methodology. Because of the nature of these critiques, suggestions for future research in this field of practice have been scattered throughout the literature and have not benefitted from a wider historical perspective. This paper examines the historical evolution of family preservation studies in child welfare and suggests future directions for research in the field. Among the suggestions the authors posit are (1) research questions should be framed by what we know about improvements in the lives of families and children served by family preservation programs; (2) future explorations should include areas that have received relatively little attention in current research, including the impact of organizational conditions on service fidelity and worker performance; (3) newer treatment models, particularly those that provide both intensive services during a crisis period and less intensive services for maintenance, should be tested; (4) data collection points in longitudinal studies should be guided by theory, and measures should change over time to reflect the theoretically expected changes in families; (5) complex measures of placement prevention and other measures that capture changes in family functioning, child well-being, and child safety, should be utilized to obtain a full picture of program effects; and (6) multiple informants should be used to provide data about program effectiveness. In addition, the authors will argue that the field should carefully consider the amount of change that should be expected from the service models delivered.
Resumo:
Background information: During the late 1970s and the early 1980s, West Germany witnessed a reversal of gender differences in educational attainment, as females began to outperform males. Purpose: The main objective was to analyse which processes were behind the reversal of gender differences in educational attainment after 1945. The theoretical reflections and empirical evidence presented for the US context by DiPrete and Buchmann (Gender-specific trends in the value of education and the emerging gender gap in college completion, Demography 43: 1–24, 2006) and Buchmann, DiPrete, and McDaniel (Gender inequalities in education, Annual Review of Sociology 34: 319–37, 2008) are considered and applied to the West German context. It is suggested that the reversal of gender differences is a consequence of the change in female educational decisions, which are mainly related to labour market opportunities and not, as sometimes assumed, a consequence of a ‘boy’s crisis’. Sample: Several databases, such as the German General Social Survey, the German Socio-economic Panel and the German Life History Study, are employed for the longitudinal analysis of the educational and occupational careers of birth cohorts born in the twentieth century. Design and methods: Changing patterns of eligibility for university studies are analysed for successive birth cohorts and gender. Binary logistic regressions are employed for the statistical modelling of the individuals’ achievement, educational decision and likelihood for social mobility – reporting average marginal effects (AME). Results: The empirical results suggest that women’s better school achievement being constant across cohorts does not contribute to the explanation of the reversal of gender differences in higher education attainment, but the increase of benefits for higher education explains the changing educational decisions of women regarding their transition to higher education. Conclusions: The outperformance of females compared with males in higher education might have been initialised by several social changes, including the expansion of public employment, the growing demand for highly qualified female workers in welfare and service areas, the increasing returns of women’s increased education and training, and the improved opportunities for combining family and work outside the home. The historical data show that, in terms of (married) women’s increased labour market opportunities and female life-cycle labour force participation, the raising rates of women’s enrolment in higher education were – among other reasons – partly explained by their rising access to service class positions across birth cohorts, and the rise of their educational returns in terms of wages and long-term employment.
Resumo:
Kosrae, or ‘The Island of The Sleeping Lady’ as it is known to locals, is the most remote island of the Federated States of Micronesia (FSM), located in the western Pacific. FSM is an independent sovereign nation consisting of four state in total: Pohnpei, Chuuk, Yap and Kosrae. First claimed by the Spanish, who were forced to cede FSM to Germany in 1899. In 1914, the Japanese took military possession of the region resulting in considerable economic, social and political change for the islands’ inhabitants. By 1947 after WWII, the islands formed part of the Trust Territory of the Pacific Islands commissioned by the UN and administered by the US. The FSM became an independent nation in 1986 while still retaining affiliation with the US under a ‘Compact of Free Association’ encouraging the officiating of English as a language of FSM, alongside local languages. Here I examine the presence and uses of English in Kosrae with reference to these socio-historical influences. First, I discuss the extralinguistic factors which have shaped the English that is currently found on Kosrae. Secondly, I assess the use of English in this community in light of Schneider’s (2007) ‘Dynamic Model’. Finally, an overview of the salient linguistic characteristics of Kosraean English, based on data collected in informal conversations on the island, will be presented. The overall objective is to present a socio-historical, political and linguistic description of a hitherto unexamined English emerging in a postcolonial environment. Schneider, E. (2007). Postcolonial Englishes. Cambridge: Cambridge University Press. Research Interests: Global Englishes