In qualitative theory of differential equations, an important role is played by special classes of solutions, like periodic solutions or solutions to some boundary value problems. When a system of ordinary differential equations has equilibria, i.e. constant solutions, whose stability properties are known, it is significant to search for connections between them by trajectories of solutions of the given system. These are called homoclinic or heteroclinic, according to whether they describe a loop based at one single equilibrium or they "start" and "end" at two distinct equilibria. This thesis is devoted to the study of heteroclinic solutions for a specific class of ordinary differential equations related to the Extended Fisher-Kolmogorov equation and the Swift-Hohenberg equation. These are semilinear fourth order bi-stable evolution equations which appear as mathematical models for problems arising in Mechanics, Chemistry and Biology. For such equations, the set of bounded stationary solutions is of great interest. These solve an autonomous fourth order equation. In this thesis, we focus on such equations having a variational structure. In that case, the solutions are critical points of an associated action functional defined in convenient functional spaces. We then look for heteroclinic solutions as minimizers of the action functional. Our main contributions concern existence and multiplicity results of such global and local minimizers in the case where the functional is defined from sign changing Lagrangians. The underlying idea is to impose conditions which imply a lower bound on the action over all admissible functions. We then combine classical arguments of the Calculus of Variations with careful estimates on minimizing sequences to prove the existence of a minimum.

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The primary purpose of this study was to investigate the effectiveness of concrete materials on fourth grade students&rsquo / geometry achievement. The secondary purpose was to investigate their opinions and feelings about instruction with concrete materials. The study was carried out in a private school in Ankara with 32 fourth grade elementary school students. One group pretest-posttest design was used. Geometry Achievement Test was administered to collect the necessary data. The instruction with concrete materials was applied by the researcher five hours per week in 10 weeks. The data were analyzed by using one-way repeated measures analysis of variance. Also, an interview was conducted with 11 students to determine their opinions and feelings about instruction with concrete materials. The results of the study revealed that there was a statistically significant change in geometry achievement of fourth grade students who participated in the instruction with concrete materials over three time periods. In other words, there were statistically significant positive changes in students&rsquo / geometry achievement across pre-intervention and post-intervention and across pre-intervention and followup. Moreover, there was no statistically significant change in students&rsquo / achievement across post-intervention and follow-up. The other results can be deducted from the study: most of the students enjoyed the class more when concrete materials were used / some of the students became anxious when they first saw the questions in preintervention / most of the students stated that questions become easier after instruction with concrete materials / cubes and the geoboard were the most useful and most liked as perceived by the students.

Das Ziel der Arbeit besteht darin, einen Beitrag zur Entwicklung der kombinatorischen Integralgeometrie zu leisten. In der Arbeit werden Bewertungen (Valuation) in den Räumen der Geraden und Ebenen im $\R^3$ betrachtet, die von Flagfunktionen abhängen. Unter geeigneten Glattheitsvoraussetzungen an die Flagfunktionen werden notwendige und hinreichende Bedingungen gegeben, die die Fortsetzung der entsprechender Bewertung zu einem signierten Maß sichern. Diese integralgeometrischen Untersuchungen führten zu einer Anzahl von interessanten Ergebnissen, speziell bei der Beschreibung von Metriken im Sinne von Hilberts viertem Problem.

Following his 1924 break with the Paris avant-garde, Francis Picabia (1879-1953) decamped to the French Riviera and soon began work on his radically new Transparency paintings. This series, which occupied Picabia from approximately 1928 to 1933, drew on classical imagery of biblical and mythological subjects, layering disparate human forms and natural motifs in sensuous compositions remarkable for their ambiguous pictorial space and sinuous lines. The Transparencies' resistance to narrative or allegory--notwithstanding their apparent clarity of reference--parallels the paintings' evasion of formal interpretation in spite of their classical beauty; both of these characteristics have made Picabia's Transparencies one of his most inscrutable and misunderstood bodies of work. To avoid treating the Transparencies as a non sequitur or as a conservative abandonment of earlier modernist goals, it is important to understand the sources of the concepts underpinning these works but originating in Picabia's earlier Cubist and Dada periods. Dimensionality, appropriation, figuration, and a rigorous commitment to individualism are all themes from Picabia's acclaimed work in the 1910s and early 1920s that continue into the Transparencies. Particularly relevant are the multivalent interpretations of the spatial fourth dimension--scientific, philosophical, and occult--that Picabia had first encountered in the context of Cubism and the Stieglitz Circle and, later, in his friend Marcel Duchamp's optical experiments. In the Transparencies Picabia's layered outlines both deny linear perspective and suggest projections of interior worlds. In 1936, Picabia affirmed his interest in the fourth dimension, referring specifically to the Transparencies' superimposition at the time he signed Charles Sirató's "Manifeste Dimensioniste." Picabia's visual synthesis of decades of avant-garde concerns in the Transparencies appealed to the American expatriate writer Gertrude Stein, who became one of Picabia's closest friends and confidantes in the early 1930s after she saw his recent paintings. Stein's commentary on Picabia's work and their friendship in "The Autobiography of Alice B. Toklas" and "Everybody's Autobiography" reveals the painter's impact on Stein at a turning point in her career, but also elucidates their shared search for new verbal and visual expressions of the human figure and higher dimensionality. / text

Background: Old-old age (80+ years) is associated with substantial cognitive decline. In this population, training-induced cognitive plasticity has rarely been studied. While earlier findings on strategy trainings suggested reduced training gains in old-old age, recent results of an extensive process-based working memory (WM) training have been more positive. Objective: Following up on previous research, the present study aimed at examining the effects of a short WM training in old-old adults and the influence of baseline WM capacity on training gains. Methods: A training group (mean age: 86.8 years) and a matched control group (mean age: 87.1 years) participated in the study. The WM training consisted of five tasks that were trained in each of 10 sessions. To evaluate possible transfer effects, executive functions were assessed with two tests before and after training. The training group was divided via median split in high- and low-capacity individuals to determine the influence of baseline WM capacity on training gains. Results: The training group improved in four of the trained tasks (medium-to-large effects). Training gains were significantly larger in the training group than in the control group in only two of those tasks. The training effects were mainly driven by the low-capacity individuals who improved in all trained tasks. No transfer effects were observed. Conclusions: These positive effects of a short WM training, particularly for low-capacity individuals, emphasize the potential for cognitive plasticity in old-old age. The absence of transfer effects may also point to its limits. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

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The intellectual and political roots of present-day China lie in the late imperial era and the transition to modern statehood. As the last chain of the thousands years of dynastic rule in China, the Qing Dynasty ended in 1911 with a revolution. Even though the Republican regime was immediately established after their revolution, it took three decades until thenew government (People&rsquo / s Republic of China) achieved full sovereignty on the territory. The thesis argues that the 1911 Revolution is a major turning point in Chinese transformation not only because of the regime change but also the ideological shift towards modern statehood. In this study, first, the social forces and actors on the eve of the Revolution are analyzed. The gentry-domination of society and the power relations within the forces involved in the Revolution - especially the intellectuals and the military - appear to be the two major reasons why the transition was not completed with the Revolution. The second focus of the study: the process of breaking with the past. In other words, how was the shift in people&rsquo / s mind achieved? In China, this turning point did not coincide with the 1911 Revolution and/or regime change. It came later in 1910s, reaching its peak in 1919, with the New Culture Movement of the May Fourth intellectuals. There had been some influential intellectuals building a nationalist discourse even before the May Fourth Movement (e.g. Liang Qichao, reformist and ideologue in late Qing dynasty) but the radical and outspoken tone of the New Culture Movement achieved the grounds for a shift in minds. I will briefly analyze the intellectual work of the period and its politicization. A special emphasis is given on Sun Yat-sen&rsquo / s political and intellectual contribution to the transition since he was not only a major political activist but also a theoretician whose works (Three Principles of People) have been influential on China&rsquo / s nation-building process.

The newly emerging Fourth Sector combines a strong social or environmental mission with business practices, and could potentially play a catalysing role in moving society towards sustainability. This thesis explores the extent that Danish social businesses and enterprises are using a strategic sustainable development approach and discusses how such an approach could potentially strengthen their core business. The analytical framework we used is the Framework for Strategic Sustainable Development, complemented with sector specific elements. To gather our data we conducted twelve semi-structured interviews with Danish social enterprises and businesses, as well as expert interviews. Main findings include that few had both social and environmental goals, that they strategise informally, and few measure their impact. Recommendations to strengthen their core business include incorporating sustainability in their definition of success, making their decision-making framework explicit, and measure and communicate impacts. / Fjärde sektorn kombinerar ett starkt engagemang inom det sociala eller miljöområdet med metoder från affärslivet. Dessa organisationer har potential att bidra till att samhället blir mer hållbart. Denna uppsats undersöker till vilken grad danska socialentreprenörer utnyttjar en strategisk ansats för hållbarhetsutveckling och diskuterar hur en sådan ansats skulle kunna stärka deras kärnverksamhet. Det analytiska ramverket som används är "Framework for Strategic Sustainable Development", som har kompletterats med sektorspecifika uppgifter. Studieresultat inkluderar att få av organisationerna satte mål inom både det sociala och miljöområdet samt att få mätte hur effekten av deras arbete. Rekommendationer för att stärka kärnverksamheten inkluderar att ta med hållbarhet inom framgångsdefinitionen, gör beslutsramverket explicit och mäta och kommunicera effekten av deras arbete. / <p>Stuart Filshie, +46 760-640 650</p>

From a sociocultural perspective, individuals learn best from contextualized experiences. In preservice teacher education, contextualized experiences include authentic literacy experiences, which include a real reader and writer and replicate real life communication. To be prepared to teach well, preservice teachers need to gain literacy content knowledge and possess reading maturity. The purpose of this study was to examine the effect of authentic literacy experiences as Book Buddies with Hispanic fourth graders on preservice teachers’ literacy content knowledge and reading maturity. The study was a pretest/posttest design conducted over 12 weeks. Preservice teacher participants, the focus of the study, were elementary education majors taking the third of four required reading courses in non-probabilistic convenience groups, 43 (n = 33 experimental, n = 10 comparison) Elementary Education majors. The Survey of Preservice Teachers’ Knowledge of Teaching and Technology (SPTKTT), specifically designed for preservice teachers majoring in elementary or early childhood education and the Reading Maturity Survey (RMS) were used in this study. Preservice teachers chose either the experimental or comparison group based on the opportunity to earn extra credit points (experimental = 30 points, comparison = 15). After exchanging introductory letters preservice teachers and Hispanic fourth graders each read four books. After reading each book preservice teachers wrote letters to their student asking higher order thinking questions. Preservice teachers received scanned copies of their student’s unedited letters via email which enabled them to see their student’s authentic answers and writing levels. A series of analyses of covariance were used to determine whether there were significant differences in the dependent variables between the experimental and comparison groups. This quasi-experimental study tested two hypotheses. Using the appropriate pretest scores as covariates for adjusting the posttest means of the subcategory Literacy Content Knowledge (LCK), of the SPTKTT and the RMS, the mean adjusted posttest scores from the experimental group and comparison group were compared. No significant differences were found on the LCK dependent variable using the .05 level of significance, which may be due to Type II error caused by the small sample size. Significant differences were found on RMS using the .05 level of significance.