919 resultados para Ostergren, Robert C.: The Europeans: a geography of people, culture and environment


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Among the Solar System’s bodies, Moon, Mercury and Mars are at present, or have been in the recent years, object of space missions aimed, among other topics, also at improving our knowledge about surface composition. Between the techniques to detect planet’s mineralogical composition, both from remote and close range platforms, visible and near-infrared reflectance (VNIR) spectroscopy is a powerful tool, because crystal field absorption bands are related to particular transitional metals in well-defined crystal structures, e.g., Fe2+ in M1 and M2 sites of olivine or pyroxene (Burns, 1993). Thanks to the improvements in the spectrometers onboard the recent missions, a more detailed interpretation of the planetary surfaces can now be delineated. However, quantitative interpretation of planetary surface mineralogy could not always be a simple task. In fact, several factors such as the mineral chemistry, the presence of different minerals that absorb in a narrow spectral range, the regolith with a variable particle size range, the space weathering, the atmosphere composition etc., act in unpredictable ways on the reflectance spectra on a planetary surface (Serventi et al., 2014). One method for the interpretation of reflectance spectra of unknown materials involves the study of a number of spectra acquired in the laboratory under different conditions, such as different mineral abundances or different particle sizes, in order to derive empirical trends. This is the methodology that has been followed in this PhD thesis: the single factors previously listed have been analyzed, creating, in the laboratory, a set of terrestrial analogues with well-defined composition and size. The aim of this work is to provide new tools and criteria to improve the knowledge of the composition of planetary surfaces. In particular, mixtures composed with different content and chemistry of plagioclase and mafic minerals have been spectroscopically analyzed at different particle sizes and with different mineral relative percentages. The reflectance spectra of each mixture have been analyzed both qualitatively (using the software ORIGIN®) and quantitatively applying the Modified Gaussian Model (MGM, Sunshine et al., 1990) algorithm. In particular, the spectral parameter variations of each absorption band have been evaluated versus the volumetric FeO% content in the PL phase and versus the PL modal abundance. This delineated calibration curves of composition vs. spectral parameters and allow implementation of spectral libraries. Furthermore, the trends derived from terrestrial analogues here analyzed and from analogues in the literature have been applied for the interpretation of hyperspectral images of both plagioclase-rich (Moon) and plagioclase-poor (Mars) bodies.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Purpose: To investigate the correlation between tests of visual function and perceived visual ability recorded with a 'quality-of-life' questionnaire for patients with central field loss. Method: 12 females and 7 males (mean age = 53.1 years; Range = 23 - 80 years) with subfoveal neovascular membranes underwent a comprehensive assessment of visual function. Tests included unaided distance vision, high and low contrast distance logMAR visual acuity (VA), Pelli-Robson contrast senstivity (at 1m), near logMAR word VA and text reading speed. All tests were done both monocularly and binocularly. The patients also completed a 28 point questionnaire separated into a 'core' section consisting of general questions about perceived visual function and a 'module' section with specific questions on reading function. Results: Step-wise multiple regression analysis was used to determine which visual function tests were correlated with the patients's perceived visual function and to rank them in order of importance. The visual function test that explains most of the variance in both 'core' score (66%0 and the 'module' score (68%) of the questionnaire is low contrast VA in the better eye (P<0.001 in both cases). Further, the module score also accounts for a significant proportion of the variance (P<0.01) of the distance logMAR VA in both the better and worse eye, and the near logMAR in both the better eye and binocularly. Conclusions: The best predictor of both perceived reading ability and of general perceived visual ability in this study is low contrast logMAR VA. The results highlight that distance VA is not the only relevant measure of visual fucntion in relation to a patients's perceived visual performance and should not be considered a determinant of surgical or management success.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The Internet poses a number of threats to the safety of young people. Using numerous examples, this article discusses a wide range of such threats, including: cyberstalking; the 'grooming' of potential victims of sexual abuse; a new 'wish list' scene (where teenagers encourage contact with potential abusers); the creation and distribution of child pornography; and the emergence of services that create child pornography to order. It is suggested that the latter has provided individuals with the ability to inflict sexual abuse on young people from a distance, an act the authors have termed virtual sex tourism. The final section of the article suggests that paedophiles and pornographers have been quick to adopt new technology as a means of concealing their activities. The article concludes by warning of the danger of overestimating or underestimating the threats described.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Novel reaction pathways for the hypervalent iodine-mediated oxidation of bioactive phenols containing extended conjugated π-systems are described. Oxidation of 4-hydroxystilbenes in methanol using a hypervalent iodine-based oxidant led to the formal 1,2-addition of methoxy groups across the central stilbene double bond. Treatment of the structurally related 4-hydroxyisoflavone with di(trifluoroacetoxy)iodobenzene leads to the surprising formation of 2,4′-dihydroxybenzil. Potential mechanisms for these new reaction pathways are discussed, and the X-ray crystal structure of 2,4′-dihydroxybenzil is presented. In contrast, oxidation of the corresponding 3-hydroxystilbenes and 3-hydroxyisoflavone led to conventional dienone oxidation products. The antitumour implications of these oxidation processes are briefly highlighted; the novel 4-substituted phenolic oxidation products were found to be inactive in terms of in vitro antitumour cellular activity, whereas the 3-substituted phenol products gave novel agents with potent and enhanced antitumour activity in the HCT 116 cancer cell line. © The Royal Society of Chemistry 2005.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the article, we have reviewed the means for visualization of syntax, semantics and source code for programming languages which support procedural and/or object-oriented paradigm. It is examined how the structure of the source code of the structural and object-oriented programming styles has influenced different approaches for their teaching. We maintain a thesis valid for the object-oriented programming paradigm, which claims that the activities for design and programming of classes are done by the same specialist, and the training of this specialist should include design as well as programming skills and knowledge for modeling of abstract data structures. We put the question how a high level of abstraction in the object-oriented paradigm should be presented in simple model in the design stage, so the complexity in the programming stage stay low and be easily learnable. We give answer to this question, by building models using the UML notation, as we take a concrete example from the teaching practice including programming techniques for inheritance and polymorphism.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This article considers young people’s socialization into mnemonic communities in 14 European countries. It argues that such socialization is an intersubjective and selective process that, to a great degree, depends on the particular social environment that conditions the discourses on pasts available to young people. Drawing on memory studies, it recognizes memory as a valid alternative to the institutionalized past (history) but envisages the two as inextricably connected. Given this, it identifies several strategies adopted by young people in order to socialize understandings of the past. While these strategies vary, some reveal receptivity to populist and far right ideologies. Our study demonstrates how internalization of political heritage via mnemonic socialization within families is conditioned by both the national political agenda and socio-economic situation experienced across Europe.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A szerzők tanulmányának célja, hogy bemutassa, milyen célokra alkalmazzák az internetet a hazai vállalatok, milyen várakozásaik vannak az e-kereskedelem versenyben betöltött szerepével kapcsolatban, és hogyan észlelik annak előnyeit. Vizsgálják azt is, hogy az elmúlt öt évben milyen változások tapasztalhatók a vállalatok gyakorlatában e téren. Elemzik továbbá, hogy a piacorientáció és a vállalat külső marketingkörnyezete hogyan befolyásolja az e-kereskedelem megítélését és alkalmazását. Elemzésük a "Versenyben a világgal" kutatási program 2009-ben készült felmérésének eredményeire támaszkodik, amelyben 300 vállalat szakembereit kérdezték meg. Kutatásukban megerősítést nyert, hogy Magyarországon az elektronikus kereskedelem jelentősége nő. A vállalatoknak kedvezőek az elektronikus kereskedelem jövőjével kapcsolatos várakozásaik, és úgy vélik, hogy ez versenyelőny forrása lehet. A vállalat piacorientációja erőteljesen befolyásolja azt, hogy egy vállalat milyen mértékben alkalmazza az internetet, és hogyan viszonyul az elektronikus kereskedelemhez / === / The objective of the authors’ research is to show how internet is used among Hungarian companies, to analyse their expectations with regard of the role e-commerce plays in competition, and the benefits resulting from e-commerce. They also focus on the changes that have taken place the past five years in the practice of Hungarian companies. The authors investigate how market orientation and the external marketing environment of firms influence evaluations of e-commerce and its implementation. Their analysis is based on the results of the research program „Competing with the world” , which includes the answers of 300 companies. Their research results confirm that the importance of e-commerce is growing in Hungary and overall Hungarian firms have positive expectations with regard of the future of e-commerce and consider it a source of competitive advantage. Market orientation of the firm strongly influences the extent of internet applications and attitudes toward ecommerce.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Subduction zone magmatism is an important and extensively studied topic in igneous geochemistry. Recent studies focus on from where arc magmas are generated, how subduction components (fluids or melts) are fluxed into the source of the magmas, and whether or how the subduction components affect partial melting processes beneath volcanic arcs at convergent boundaries. ^ At 39.5°S in the Central Southern Volcanic Zone of the Andes, Volcano Villarrica is surrounded by a suite of Small Eruptive Centers (SEC). The SECs are located mostly to the east and northeast of the stratovolcano and aligned along the Liquine-Ofqui Fault Zone, the major fracture system in this area. Former studies observed the geochemical patterns of the SECs differ distinctively from those of V. Villarrica and suggested there may be a relationship between the compositions of the volcanic units and their edifice sizes. This work is a comprehensive geochemical study on the SECs near V. Villarrica, using a variety of geochemical tracers and tools including major, trace and REE elements, Li-Be-B elements, Sr-Nd-Pb isotopes and short-lived isotopes such as U-series and 10Be. In this work, systematic differences between the elemental and isotopic compositions of the SECs and those of V. Villarrica are revealed and more importantly, modeled in terms of magmatic processes occurring at continental arc margins. Detailed modeling calculations in this work reconstruct chemical compositions of the primary magmas, source compositions, compositions and percentages of different subduction endmembers mixed into the source, degrees of partial melting and different time scales of the SECs and V. Villarrica, respectively. Geochemical characteristics and possible origins of the two special SECs—andesitic Llizan, with crustal signatures, and Rucapillan, to the northwest toward the trench, are also discussed in this work. ^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

President Jimmy Carter once said, "I had a different way of governing." In attempting to explain what he meant by this, Carter has been variously described as a political amateur, a trustee, a non-political politician, an "active-positive" president, and a forerunner of the 1990s' New Democrats. It is argued here, however, that mere secular descriptions and categories such as these do not adequately capture the essence of Carter's brand of politics and his understanding of the presidency. Rejecting Richard Neustadt's prescriptions for effective presidential leadership, Carter thought political bargaining and compromise were "dirty" and "sinful." He deemed the ways of Washington as "evil," and considered many, if not most, career politicians immoral. While he fully supported the institutional separation of church and state, politics for Carter was about "doing right," telling the truth, and making the United States and the world "a better demonstration of what Christ is." Like two earlier Democrats, William Jennings Bryan and Woodrow Wilson, Carter understood politics as an alternative form of Christian ministry and service. In this regard, Carter was a presidential exception. Carter's evangelical faith gave his politics meaning, skill, vision, and a framework for communication. Using Fred Greenstein's categories of presidential leadership, Carter's faith provided him with "emotional intelligence", too. However, Carter's evangelical style provoked many of his contemporaries, including many of his fellow Democrats. To his critics at home and abroad, Carter was often accused of being arrogant, stubborn, naive, and ultimately a political failure. But as evinced by his indispensable role in negotiating peace between Israel and Egypt, his leadership style also provided him some remarkable achievements. The research here is based on a thorough examination of President Carter's many writings, his public papers, interviews, and opinion pieces. Written accounts from former Carter administration officials and from Israeli and Egyptian participants at Camp David are also used. This project is largely descriptive, qualitative in approach, but quantitative data are used when appropriate and as supplements.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Ocean acidification, as a result of increased atmospheric CO2, has the potential to adversely affect the larval stages of many marine organisms and hence have profound effects on marine ecosystems. This is the first study of its kind to investigate the effects of ocean acidification on the early life-history stages of three echinoderms species, two asteroids and one irregular echinoid. Potential latitudinal variations on the effects of ocean acidification were also investigated by selecting a polar species (Odontaster validus), a temperate species (Patiriella regularis), and a tropical species (Arachnoides placenta). The effects of reduced seawater pH levels on the fertilization of gametes, larval survival and morphometrics on the aforementioned species were evaluated under experimental conditions. The pH levels considered for this research include ambient seawater (pH 8.1 or pH 8.2), levels predicted for 2100 (pH 7.7 and pH 7.6) and the extreme pH of 7.0, adjusted by bubbling CO2 gas into filtered seawater. Fertilization for Odontaster validus and Patiriella regularis for the predicted scenarios for 2100 was robust, whereas fertilization was significantly reduced in Arachnoides placenta. Larval survival was robust for the three species at pH 7.8, but numbers declined when pH dropped below 7.6. Normal A. placenta larvae developed in pH 7.8, whereas smaller larvae were observed for O. validus and P. regularis under the same pH treatment. Seawater pH levels below 7.6 resulted in smaller and underdeveloped larvae for all three species. The greatest effects were expected for the Antarctic asteroid O. validus but overall the tropical sand dollar A. placenta was the most affected by the reduction in seawater pH. The effects of ocean acidification on the asteroids O. validus and P. regulars, and the sand dollar A. placenta are species-specific. Several parameters, such as taxonomic differences, physiology, genetic makeup and the population's evolutionary history may have contributed to this variability. This study highlights the vulnerability of the early developmental stages and the complexity of ocean acidification. However, future research is needed to understand the effects at individual, community and ecosystem levels.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

All teachers participate in self-directed professional development (PD) at some point in their careers; however, the degree to which this participation takes place varies greatly from teacher to teacher and is influenced by the leadership of the school principal. The motivation behind why teachers choose to engage in PD is an important construct. Therefore, there is a need for better understanding of the leader’s role with respect to how and why teachers engage in self-directed professional development. The purpose of the research was to explore the elementary teachers’ motivation for and the school principal’s influence on their engagement in self-directed professional development. Three research questions guided this study: 1. What motivates teachers to engage in self-directed professional development? 2. What are the conditions necessary for promoting teachers’ engagement in self-directed professional development? 3. What are teachers’ perceptions of the principal’s role in supporting, fostering, encouraging, and sustaining the professional development of teachers? A qualitative research approach was adopted for this study. Six elementary teachers from one south-eastern Ontario school board, consisting of three novice and three more experienced teachers, provided their responses to a consistent complement of 14 questions. Their responses were documented via individual interviews, transcribed verbatim, and thematically analysed. The findings suggested that, coupled with the individual motivating influences, the culture of the school was found to be a conditional dynamic that either stimulated or dissuaded participation in self-directed PD. The school principal provided an additional catalyst or deterrence via relational disposition. When teachers felt their needs for competency, relatedness, and autonomy were satisfied, the conditions necessary to motivate teachers to engage in PD were fulfilled. A principal who personified the tenets of transformational leadership served to facilitate teachers’ inclinations to take on PD. A leadership style that was collaborative and trustful and allowed for personal autonomy was a dominant foundational piece that was critical for participant participation in self-directed PD. Finally, the principals were found to positively impact school climate by partaking in PD alongside teachers and ensuring there was a shared vision of the school so that teachers could tailor PD to parallel school interests.