977 resultados para Historical method


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Microvascular surgery has become an important method for reconstructing surgical defects due to trauma, tumors or after burn. The most important factor for successful free flap transfer is a well-executed anastomosis. The time needed to perform the anastomosis and the failure rate are not negligible despite the high level of operator's experience. During the history, many alternatives were tried to help the microsurgeon and to reduce the complications. A Medline literature search was performed to find articles dealing with non-suture methods of microvascular anastomosis. Many historical books were also included. The non-suture techniques can be divided into four groups based on the used mechanism of sutures: double intubation including tubes and stents, intubation-eversion including simple rings, double eversion including staples and double rings, and wall adjustement with adhesives or laser. All these techniques were able to produce a faster and easier microvascular anastomosis. Nevertheless, disadvantages of the suturless techniques include toxicity, high cost, leakage or aneurysm formation. More refinement is needed before their widespread adoption. Thus, laser-assisted microvascular anastomosis using 1,9 μm diode laser appeared to be a safe and reliable help for the microsurgeon and may be further developed in the near future.

Relevância:

30.00% 30.00%

Publicador:

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.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

To improve our understanding of the Asian monsoon system, we developed a hydroclimate reconstruction in a marginal monsoon shoulder region for the period prior to the industrial era. Here, we present the first moisture sensitive tree-ring chronology, spanning 501 years for the Dieshan Mountain area, a boundary region of the Asian summer monsoon in the northeastern Tibetan Plateau. This reconstruction was derived from 101 cores of 68 old-growth Chinese pine (Pinus tabulaeformis) trees. We introduce a Hilbert–Huang Transform (HHT) based standardization method to develop the tree-ring chronology, which has the advantages of excluding non-climatic disturbances in individual tree-ring series. Based on the reliable portion of the chronology, we reconstructed the annual (prior July to current June) precipitation history since 1637 for the Dieshan Mountain area and were able to explain 41.3% of the variance. The extremely dry years in this reconstruction were also found in historical documents and are also associated with El Niño episodes. Dry periods were reconstructed for 1718–1725, 1766–1770 and 1920–1933, whereas 1782–1788 and 1979–1985 were wet periods. The spatial signatures of these events were supported by data from other marginal regions of the Asian summer monsoon. Over the past four centuries, out-of-phase relationships between hydroclimate variations in the Dieshan Mountain area and far western Mongolia were observed during the 1718–1725 and 1766–1770 dry periods and the 1979–1985 wet period.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Reconstructing past landscapes from historical maps requires quantifying the accuracy and completeness of these sources. The accuracy and completeness of two historical maps of the same period covering the same area in Israel were examined: the 1:63,360 British Palestine Exploration Fund map (1871-1877) and the 1:100,000 French Levés en Galilée (LG) map (1870). These maps cover the mountainous area of the Galilee (northern Israel), a region with significant natural and topographical diversity, and a long history of human presence. Land-cover features from both maps, as well as the contours drawn on the LG map, were digitized. The overall correspondence between land-cover features shown on both maps was 59% and we found that the geo-referencing method employed (transformation type and source of control points) did not significantly affect these correspondence measures. Both maps show that in the 1870s, 35% of the Galilee was covered by Mediterranean maquis, with less than 8% of the area used for permanent agricultural cropland (e.g., plantations). This article presents how the reliability of the maps was assessed by using two spatial historical sources, and how land-cover classes that were mapped with lower certainty and completeness are identified. Some of the causes that led to observed differences between the maps, including mapping scale, time of year, and the interests of the surveyors, are also identified.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

At the present time almost all map libraries on the Internet are image collections generated by the digitization of early maps. This type of graphics files provides researchers with the possibility of accessing and visualizing historical cartographic information keeping in mind that this information has a degree of quality that depends upon elements such as the accuracy of the digitization process and proprietary constraints (e.g. visualization, resolution downloading options, copyright, use constraints). In most cases, access to these map libraries is useful only as a first approach and it is not possible to use those maps for scientific work due to the sparse tools available to measure, match, analyze and/or combine those resources with different kinds of cartography. This paper presents a method to enrich virtual map rooms and provide historians and other professional with a tool that let them to make the most of libraries in the digital era.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In this paper, a computer-based tool is developed to analyze student performance along a given curriculum. The proposed software makes use of historical data to compute passing/failing probabilities and simulates future student academic performance based on stochastic programming methods (MonteCarlo) according to the specific university regulations. This allows to compute the academic performance rates for the specific subjects of the curriculum for each semester, as well as the overall rates (the set of subjects in the semester), which are the efficiency rate and the success rate. Additionally, we compute the rates for the Bachelors degree, which are the graduation rate measured as the percentage of students who finish as scheduled or taking an extra year and the efficiency rate (measured as the percentage of credits of the curriculum with respect to the credits really taken). In Spain, these metrics have been defined by the National Quality Evaluation and Accreditation Agency (ANECA). Moreover, the sensitivity of the performance metrics to some of the parameters of the simulator is analyzed using statistical tools (Design of Experiments). The simulator has been adapted to the curriculum characteristics of the Bachelor in Engineering Technologies at the Technical University of Madrid(UPM).

Relevância:

30.00% 30.00%

Publicador:

Resumo:

From 1995 to 1999 Monika Wulf-Mathies served as EU commissioner responsible for regional and cohesion policy. She tells us the story of the EU Commission under President Jacques Santer with regard to the historical development of the preparation of the Economic and Monetary Union (EMU), the Union Treaty of Amsterdam (1999) and the EU-Eastern Enlargement. She touches also controversial aspects of the Santer Commission, which led to her collective demission in 1999. According to Wulf-Mathies the increase of EU's democracy deficit is result of an erosion process of the common institutions caused by the nation states which contributed to their weakness. The democratic substance of the union suffers because of the 'summarization' of the EU decision making processes. Monika Wulf-Mathies argues in favor of the community method, which needs revitalization. She proposes European democracy enforcement and transfers of the national budget und economy policies to EU bodies. This eyewitness talk offers an actual EU analysis as well as an assessment of the Santer Commission.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The paper deals with digitization as a method of protecting and preserving cultural and historical heritage of Armenians in Bulgaria. It attempts to establish the level of development of this process in the country, to identify the good examples and information gaps in order to outline the priorities and perspectives.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A kameralizmus a 16-18. századi német gyakorlati államtudomány és egyetemi tantárgy volt, amely összefoglalta a hivatalnokok képzéséhez szükséges elméleti és gyakorlati gazdasági ismereteket. Felfogása szerint az alattvalók jóléte és boldogsága feltétele az uralkodó gazdagságának, de az alattvalók önmaguktól nem képesek utat találni ehhez a boldogsághoz, szükség van az állandó külső irányításra. Igazgatásközpontúsága és egyetemi intézményesülése miatt nem tekinthető a merkantilizmus helyi változatának. Az 1840 és 1945 közötti német történeti iskola hagyományos ábrázolása több mint egy évszázadon át a német és a neoklasszikus tradíció szembenállását hangsúlyozta, kiemelve az organicizmus, a fejlődésgondolat és az egyediség jelentőségét, a szociális kérdés fontosságát, illetve a deduktív módszer és a gazdaság változatlan törvényeinek tagadását. A modern rekonstrukciók a történeti iskolát a posztklasszikus válságra adott egyik európai válaszként fogják fel, amely a történelemből levont, empirikusan megalapozott induktív alternatívát kínált. Az 1871-től kialakult osztrák iskola a neoklasszikus paradigmának egyszerre volt alkotórésze és versenytársa. A módszertani individualizmus, a szubjektivizmus, az idő fontossága, a tudás szerepe, az alternatív költségek elmélete stb. ugyan beépültek a mainstream közgazdaságtanba, de hangsúlyos kiemelésük lehetővé tette, hogy a társadalomelméleti magyarázat igényét őrző osztrák iskola megtartson valamit önálló beszédmódjából. / === / Cameralism was a practical political science and university subject in 16th–18th century Germany, summarizing the theoretical and practical economic knowledge required in the training of officials. The assumption was that the prosperity of the ruler depended on the welfare and happiness of the subjects, but the subjects themselves were not capable of achieving this happiness without permanent directions from above. Cameralism’s emphasis on administration and university institutionalization means that this approach cannot be seen as a local variant of mercantilism. The traditional account of the German historical school from 1840 to 1945 emphasized for over a century the contrast between the German and the Neoclassical traditions. It underlined the significance of the organic approach, the concept of development and individuality, the importance of the social question, and the denial of the deductive method and unalterable laws of the economy. Modern reconstructions see the historical school as one European response to the post-Classical crisis, offering an inductive alternative grounded empirically on history. The Austrian school formed in 1871 was at once a constituent of the Neoclassical paradigm and a rival to it. Methodological individualism, subjectivism, the importance of time, the role of knowledge, the theory of alternative costs etc. were absorbed into mainstream economics, but the focusing on these issues allowed the Austrian school, in keeping alive its demand for a social-theoretical explanation, to preserve something of an alternative discourse.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This is a historical case study on school desegregation and power in Broward County, Florida from 1970 to 1998. The purpose of this study is to describe, explain and analyze types of power used by the School Board of Broward County, Florida and community activists, in their efforts to influence desegregation decisions from 1970 to 1998. In addition, this study explains who benefited and who won from the School Board's desegregation decisions and who governed those decisions? ^ A historical case study approach was used as the method for conducting this study. Data sources included 11 interviews of individuals who were involved in school desegregation issues as either School Board officials or community activists and 10 archival data sources. ^ The theoretical models of Russell, Galbraith, Wartenberg and Domhoff were used to determine the different types of power techniques used by School Board officials and community activists and to answer the questions: who benefited and who won from the School Board's desegregation decisions and who governed those policies and practices? ^ The primary beneficiaries of school desegregation policies and practices in Broward County were: white, affluent communities and the builders, developers, realtors and other businesses in the western suburban communities. All of the data sources indicated that the black community did not benefit from the School Board's desegregation policies. ^ The primary power techniques used by School Board officials to influence desegregation policies and practices was “power over opinions” and compensation. These power techniques were manifested by the School Board publicly disputing the allegations raised by community activists and by compensating those who supported and promoted the School Board's desegregation policies and practices. ^ The power techniques primarily used by community activists were coercive force and “power over opinions.” They effectively used these power techniques to change the School Board's policies and practices they felt were detrimental to black children and the black community. ^ Based on the analysis of the qualitative data, it can be concluded that black children did not benefit from school desegregation in Broward County, Florida and the community continues to suffer residual effects from past desegregation policies and practices. ^

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This is a historical case study on school desegregation and power in Broward County, Florida from 1970 to 1998. The purpose of this study is to describe, explain and analyze types of power used by the School Board of Broward County, Florida and community activists, in their efforts to influence desegregation decisions from 1970 to 1998. In addition, this study explains who benefited and who won from the School Board's desegregation decisions and who governed those decisions? A historical case study approach was used as the method for conducting this study. Data sources included 11 interviews of individuals who were involved in school desegregation issues as either School Board officials or community activists and 10 archival data sources. The theoretical models of Russell, Galbraith, Wartenberg and Domhoff were used to determine the different types of power techniques used by School Board officials and community activists and to answer the questions: who benefited and who won from the School Board's desegregation decisions and who governed those policies and practices? The primary beneficiaries of school desegregation policies and practices in Broward County were: white, affluent communities and the builders, developers, realtors and other businesses in the western suburban communities. All of the data sources indicated that the black community did not benefit from the School Board's desegregation policies. The primary power techniques used by School Board officials to influence desegregation policies and practices was "power over opinions" and compensation. These power techniques were manifested by the School Board publicly disputing the allegations raised by community activists and by compensating those who supported and promoted the School Board's desegregation policies and practices. The power techniques primarily used by community activists were coercive force and "power over opinions." They effectively used these power techniques to change the School Board's policies and practices they felt were detrimental to black children and the black community. Based on the analysis of the qualitative data, it can be concluded that black children did not benefit from school desegregation in Broward County, Florida and the community continues to suffer residual effects from past desegregation policies and practices.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This paper provides a method for constructing a new historical global nitrogen fertilizer application map (0.5° × 0.5° resolution) for the period 1961-2010 based on country-specific information from Food and Agriculture Organization statistics (FAOSTAT) and various global datasets. This new map incorporates the fraction of NH+4 (and NONO-3) in N fertilizer inputs by utilizing fertilizer species information in FAOSTAT, in which species can be categorized as NH+4 and/or NO-3-forming N fertilizers. During data processing, we applied a statistical data imputation method for the missing data (19 % of national N fertilizer consumption) in FAOSTAT. The multiple imputation method enabled us to fill gaps in the time-series data using plausible values using covariates information (year, population, GDP, and crop area). After the imputation, we downscaled the national consumption data to a gridded cropland map. Also, we applied the multiple imputation method to the available chemical fertilizer species consumption, allowing for the estimation of the NH+4/NO-3 ratio in national fertilizer consumption. In this study, the synthetic N fertilizer inputs in 2000 showed a general consistency with the existing N fertilizer map (Potter et al., 2010, doi:10.1175/2009EI288.1) in relation to the ranges of N fertilizer inputs. Globally, the estimated N fertilizer inputs based on the sum of filled data increased from 15 Tg-N to 110 Tg-N during 1961-2010. On the other hand, the global NO-3 input started to decline after the late 1980s and the fraction of NO-3 in global N fertilizer decreased consistently from 35 % to 13 % over a 50-year period. NH+4 based fertilizers are dominant in most countries; however, the NH+4/NO-3 ratio in N fertilizer inputs shows clear differences temporally and geographically. This new map can be utilized as an input data to global model studies and bring new insights for the assessment of historical terrestrial N cycling changes.