Growth and decay of localized disturbances on a surfactant-coated spreading film

If the surface of a quiescent thin liquid film is suddenly coated by a patch of surface active material like a surfactant monolayer, the film is set in motion and begins spreading. An insoluble surfactant will rapidly attempt to coat the entire surface of the film thereby minimizing the liquid's surface tension. The shear stress that develops during the spreading process produces a maximum in surface velocity in the region where the moving film meets the quiescent layer. This region is characterized by a shock front with large interfacial curvature and a corresponding local buildup of surfactant which creates a spike in the concentration gradient. In this paper, we investigate the sensitivity of this region to infinitesimal disturbances. Accordingly, we introduce a measure of disturbance amplification and transient growth analogous to a kinetic energy that couples variations in film thickness to the surfactant concentration. These variables undergo significant amplification during the brief period in which they are convected past the downstream tip of the monolayer, where the variation in concentration gradient and surface curvature are largest. Once they migrate past this sensitive area, the perturbations weaken considerably and the system approaches a stable configuration. It appears that the localized disturbances of the type we consider here, cannot sustain asymptotic instability. Nonetheless, our study of the dynamics leading to the large transient growth clearly illustrates how the coupling of Marangoni and capillary forces work in unison to stabilize the spreading process against localized perturbations

Thinning and disturbance growth in liquid films mobilized by continuous surfactant delivery

A generalized linear stability analysis is applied to the case of a thin liquid film propelled to spread by a continuous supply of surfactant. The time-dependent base states for the film thickness and surfactant concentration give rise to a nonautonomous system describing disturbance propagation. As a first approximation, the nonautonomous operator is treated as time independent, thereby reducing the system of equations to a standard eigenvalue problem. For the range of parameters investigated, this modal approximation reveals a band of unstable modes corresponding to the growth of transverse, sinusoidal corrugations. A transient growth analysis of the fully time-dependent system, which requires the solution of an initial value problem, also signals the possibility of large disturbance growth. In both cases, significant amplification of infinitesimal disturbances can be traced to the region of the film most rapidly thinned by Marangoni stresses, which is characterized by large interfacial curvature and a sharp variation in shear stress. In contrast to previous models implementing a finite surfactant source that predict asymptotic stability, large transient growth and asymptotic instability are possible for the case of sustained surfactant release

Theoretical and experimental investigations on the exploitation of heterosis in hybrid breeding

Hybrid breeding has played a key role in the improvement of the productivity of many crops. Genetic variability, an essential prerequisite in plant breeding, is expected to decrease in heterotic groups as a result of continuous breeding efforts. The consequences of the narrowing of genetic variability are a decrease in selection gain and an increase in the susceptibility of cultivars. Thus, establishment of heterotic groups and broadening the genetic base of established heterotic groups are very important research topics in hybrid breeding. Our objectives were to (1) evaluate heterosis in winter triticale and identify heterotic groups based on field and SSR marker data, (2) investigate by field evaluations and SSR markers the heterotic relationships between the Central European heterotic groups in maize and rye and exotic germplasm from the US and Eastern Europe, respectively, and (3) monitor temporal changes over 30 years in the magnitude of variances due to general combining ability (GCA) and specific combining ability (SCA) in an applied hybrid maize breeding program. Triticale has low heterosis and, therefore, no hybrid cultivars have been developed, although an effective CMS system is available. Twenty-one lines and their 210 diallel crosses were field-evaluated for grain yield at five locations in Germany. 95 SSR markers were used to analyze the parents for identifying two diverse subgroups. Hybrid performance, midparent heterosis, and estimates of variance due to GCA and SCA were determined in a diallel, a 10 × 11 factorial, and the remaining two sub-diallels with 10 and 11 parents. In addition, we applied an enumeration algorithm, which explored the entire sample space to identify diverse heterotic groups and optimize different criteria in this context. The ratio of variance due to GCA to variance due to SCA was higher for factorials between groups of parents than in diallels and subdiallels within groups. The analyses indicated a more favorable ratio in situations with genetically distinct populations compared to situations with genetically less distinct populations. Application of the enumeration algorithm improved all criteria. F1 performance followed by heterosis were the most important criteria for development and enrichment of heterotic groups. Introgression of new germplasm to broaden the genetic base of heterotic groups is required to ensure continued genetic gains in hybrid breeding. In maize, we evaluated 19 inbreds belonging to two Central European heterotic groups and US heterotic groups and their factorial crosses in F1 and F2 generations for grain yield and dry matter concentration. The parental inbreds were additionally fingerprinted with 266 SSR markers. Multi-environment evaluation was performed in three mega-environments: Central Europe, US Cornbelt, and Southeast Europe. We found higher genetic diversity in the exotic germplasm than in the Central European heterotic groups. Based on F1 performance and heterosis, we conclude that non-Stiff Stalk germplasm should be introgressed into the Flint group and the Stiff Stalk germplasm into the Dent group. In rye, we evaluated testcrosses of 610 S0 clones belonging to the two Central European heterotic groups and five East European open-pollinated varieties (OPVs). S0 clones were fingerprinted with 30 SSR markers. We found higher genetic diversity in the OPVs compared to the Central European heterotic groups. The Carsten group had a narrow genetic base and should, therefore, be the primary target for genetic broadening. Nevertheless, all five OPVs were genetically closer to Petkus than Carsten. Two OPVs were identified as good candidates for introgression into Petkus and one into Carsten. We suggest to use selected clones of these populations for introgression. Continuous selection is expected to narrow the genetic base of heterotic groups over time. We studied the nature and magnitude of genetic variability in the breeding materials of the maize program of the University of Hohenheim, which is based on two heterotic groups with continuous enrichment by other germplasm. The data generated in multilocation field trials based on inter-group factorial designs conducted from 1975 to 2004 for grain yield and dry matter concentration were analyzed. There was neither a decrease in the magnitude of genetic variance nor a change in the predominance of variance due to GCA over variance due to SCA. Consequently, for avoiding the adverse effects of selection on genetic variation and for ensuring medium and long-term selection gains, heterotic groups should not be treated as closed populations, but should be continuously enriched by introgression of new germplasm.Für die Verbesserung vieler Kulturpflanzen spielt die Hybridzüchtung eine Schlüsselrolle. Genetische Varianz ist eine wichtige Voraussetzung für Pflanzenzüchtung, die bedingt durch den kontinuierlichen Züchtungsfortschritt in heterotischen Gruppen, abnimmt. Konsequenzen sind sinkender Selektionsgewinn und steigende Anfälligkeit der Sorten. Deshalb sind die Etablierung und die Erweiterung heterotischer Gruppen sehr wichtig für die Hybridzüchtung. Die Ziele sind: (1) Bewertung der Heterosis in Inzuchtlinien von Wintertriticale und Bestimmung heterotischer Gruppen basierend auf Feld- und SSR-Markerdaten, (2) Untersuchung der heterotischen Beziehungen zwischen den mitteleuropäischen heterotischen Gruppen bei Mais und Roggen und exotischem Genmaterial aus den USA und Osteuropa basierend auf Ergebnissen von Feldexperimenten und SSR-Markern, sowie (3) Untersuchungen der Veränderung des Ausmaßes an Varianz der allgemeinen (GCA) und der spezifischen Kombinationsfähigkeit (SCA) in einem Hybridmaiszuchtprogramm über 30 Jahre. Triticale hat eine niedrige Heterosis, weshalb keine Hybridsorte entwickelt wurde, obwohl ein effektives CMS System vorhanden ist. In unserer Studie wurden 21 Linien und ihre 210 diallelen Kreuzungen auf Kornertrag in Feldexperimenten bewertet. Die Eltern wurden mit 95 SSR-Markern analysiert, um verschiedene Untergruppen zu identifizieren. Hybridleistung, Heterosis und Schätzwerte für GCA- und SCA-Varianz wurden in einem Diallel, einem 10 x 11 faktoriellen Kreuzungsschema und den verbleibenden zwei Unterdiallelen bestimmt. Zusätzlich wurde ein Aufzählungsalgorithmus verwendet, der alle Kombinationen bestehend aus zwei disjunkten Untermengen von Linien untersucht, um heterotisches Genmaterial zu identifizieren und verschiedene Kriterien in diesem Kontext zu optimieren. Das Verhältnis der GCA- zur SCA-Varianz war für die faktoriellen Kreuzungen größer als in den diallelen Kreuzungen und Unterdiallelen. Die Ergebnisse zeigten, dass in Situationen mit genetisch verschieden Populationen ein günstigeres Verhältnis der GCA- zur SCA-Varianz erreicht werden kann als mit Populationen, die nicht genetisch verschieden sind. Mit dem Aufzählungsalgorithmus konnte eine Verbesserung aller Kriterien erreicht werden (F1 Leistung gefolgt von Heterosis sind die wichtigstenKriterien für die Entwicklung und Erweiterung der heterotischen Gruppen). Die Introgression neuen Genmaterials zur Verbreiterung der genetischen Basis von heterotischen Gruppen ist erforderlich, um einen kontinuierlichen Selektionsfortschritt in der Hybridzüchtung sicherzustellen. In einer Maisstudie untersuchten wir 19 Inzuchtlinien aus zwei mitteleuropäischen und drei amerikanischen heterotischen Gruppen. Die faktoriellen Kreuzungen in den Generationen F1 und F2 wurden für die Eigenschaften Kornertrag und Korntrockensubstanzgehalt geprüft. Die Eltern wurden mit 266 SSR-Markern genotypisiert. Die Prüfglieder wurden in mehreren Umwelten in drei Mega-Umwelten getestet: Mitteleuropa, US Cornbelt und Südosteuropa. In dem exotischen Genmaterial wurde eine höhere genetische Diversität gefunden als in den mitteleuropäischen heterotischen Gruppen. Aufgrund der F1 Leistung und Heterosis konnte der Schluss gezogen werden, dass eine Einlagerung von non-Stiff Stalk Genmaterial in Flint und Stiff Stalk Genmaterial in Dent empfehlenswert ist. In einer Roggenstudie wurden Testkreuzungen von 610 S0 Klonen, die den beiden mitteleuropäischen heterotischen Gruppen und fünf osteuropäischen offenabblühenden Populationenssorten (OPVs) angehörten, bewertet. Die S0 Klone wurden mit 30 SSR-Markern genotypisiert. In den OPVs lag eine höhere genetische Diversität vor als in den mitteleuropäischen heterotischen Gruppen. Carsten hatte eine engere genetische Basis und sollte deshalb vorrangig erweitert werden. Trotzdem waren alle fünf OPVs genetisch näher an Petkus. Zwei Populationen wurden als gute Kandidaten für die Erweiterung der genetischen Diversität von Petkus und eine für die Erweiterung von Carsten eingestuft. Dabei könnten einzelne Klone dieser Populationen für die Introgression verwenden werden. Es wird erwartet, dass Selektion über längere Zeit die genetische Basis der heterotischen Gruppen einengt. Wir untersuchten die Art und das Ausmaß genetischer Varianz im Maiszuchtmaterial der Universität Hohenheim, welches auf zwei heterotischen Gruppen basiert, die kontinuierlich mit anderem Genmaterial erweitert wurden. Es wurden Leistungsprüfungsergebnisse aus den Jahren 1975 bis 2004 für Kornertrag und Korntrockensubstanzgehalt aus mehrortig geprüften faktoriellen Kreuzungen zwischen Flint- und Dent-Linien ausgewertet. Es konnte weder eine Reduktion der genetischen Varianz noch eine Änderung im Verhältnis der GCA- zur SCA-Varianz festgestellt werden. Daraus folgt, dass heterotische Gruppen nicht als geschlossene Populationen zu betrachten sind, sondern kontinuierlich durch Introgression von neuem Genmaterial erweitert werden sollten

Multilateral Trade Agreements and Market-Based Environmental Policies

We review the legal provisions of the WTO regime that have important implications for national, market-based environmental policies. We evaluate those provisions for their effects on a member country’s ability and incentives to design economically efficient environmental policies. International trade institutions do not recognize the polluter pays principle, posing some challenges for unilateral policies addressing cross-border pollutants and leakage. Nor do they recognize the economic equivalence of emission tax and permit regimes, leading to different potential constraints on policy design and leaving some environmental policies open to influence by protectionist motives. As many legality issues have yet to be disputed and resolved, opportunities exist to help the WTO and environmental institutions evolve in ways to enable and encourage good policymaking.trade, environment, WTO, GATT, market-based policies

Imagens de Amor de Mãe: quadriculamentos e escapatórias

The essay discusses framings and gridlines in images of the telenovela Amor de Mãe. The analysis lies on the functioning of family bonds/convivialities, their labile articulations amid anesthetic landscapes/aesthetic spaces, and fiction/reality interchanges. In this context, the following issues are examined: (1) meaning effects and sensorial gaps which may provide aesthetic appropriations; (2) escapes that enable active bodies to assume affective dispositions and sustain synesthetic relationships. It is concluded that the framings that show checkered characters immersed in restrictive practices and routines also reveal fissures that allow physical and symbolic exits.O estudo discute enquadramentos/quadriculamentos na telenovela Amor de Mãe, analisando a imagética de vínculos/convívios familiares, a labilidade com que se articulam entre paisagens anestésicas/espaços estésicos e os intercâmbios entre ficção e realidade. Examinam-se, em tal contexto: (1) efeitos de sentido e brechas sensíveis facultativas de apropriações estésicas; e (2) escapatórias que possibilitam a corpos ativos assumirem disposições afetivas e sustentarem relações sinestésicas. Conclui-se que os enquadramentos que dão a ver personagens quadriculadas em práticas cotidianas estruturadas a partir de apresamentos revelam, não obstante, fissuras que permitem a construção de saídas físicas e simbólicas

Unge Viser Vej – mobilitet og ungdomsuddannelser

Lange afstande og centraliseringer af uddannelser rammer de unges transport til uddannelsesstederne, derfor er der brug for at understøtte de unges mobilitet. I februar 2017 afholdt Movia et pilotprojekt i samarbejde med Region Sjælland, Holbæk og Odsherred kommune. På to temadage om mobilitet arbejdede 100 unge med at finde løsninger til forskellige transportudfordringer. Formålet var at samle viden og inspiration til udarbejdelsen af et undervisningsforløb, der giver kommunerne et værktøj til at forbedre transporten og mobiliteten til og fra uddannelse for unge, i et samarbejde med de unge selv. Til august afprøves et tilpasset undervisningsforløb som efterfølgende skal være tilgængeligt for kommuner og ungdomsuddannelser i hele landet og kan bruges på tværs af flere klasser og ungdomsuddannelser

Vilões, Heróis e Lugares na Telenovela Brasileira Contemporânea: a Favorita e Insensato Coração

O trabalho explora a questão vilão/herói na telenovela brasileira contemporânea a partir dos universos narrativos de A favorita (2008/2009, João Emanuel Carneiro, Rede Globo de Televisão) e de Insensato coração (2011, Gilberto Braga e Roberto Linhares, Rede Globo de Televisão).The essay explores the issues of villains and heroes in contemporary Brazilian soap-opera – focusing on the narrative universes of A favorita (2008/2009, João Emanuel Carneiro, Rede Globo de Televisão) and Insensato coração (2011, Gilberto Braga and Roberto Linhares, Rede Globo de Televisão)

Influence of Attachment Styles on Relationship Satisfaction

This poster was presented at the Great Plains Honors Conference in Siloam Springs, Arkansas.https://scholarworks.uttyler.edu/student_posters/1014/thumbnail.jp

Image, focus and hybridization: more of the same in publicity

Contemporary fashion and clothes griffes publicity campaigns tend both to suffer a process of hybridization and to deviate the focus from their specific products to drive attention and emphasize concepts, identities, attitudes and ways of self-presenting and social performance related to the universe of consumers they intend to be associated with. Based upon these evidences and relying on hybridization notions and on studies developed by Mikhail Bakhtin, this work aims at outlining appointments to a comparative study between two pieces of advertisements that integrate campaigns divulged by the griffes of clothes and accessories Forum and Diesel. The intention is to explore both the thematic and figurative hybridization between the referred campaigns and their consequent interrelations.As imagens que se verificam em campanhas publicitárias de moda e de marcas de roupas cada vez mais tendem à hibridização e ao pretenso desvio de foco, esmaecendo a imagem do produto roupa propriamente dito para enfatizar imagens que carregam conceitos e modos de se dar a ver e de se colocar no mundo específicos e atinentes ao universo identitário com os quais as marcas pretendem se associar. Partindo de tais evidências e à luz de pressupostos teóricos que englobam noções ampliadas de hibridização e o conceito de carnavalização bakhtiniano, este trabalho tem a intenção de desenvolver reflexões para um estudo comparativo entre duas peças integrantes de campanhas veiculadas pelas griffes de roupas e acessórios Forum e Diesel. A hibridização temática e figurativa entre as campanhas e suas conseqüentes inter-relações é o que se pretende explorar neste artigo