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On b-colorings and b-continuity of graphsAlkhateeb, Mais 24 July 2012 (has links) (PDF)
A b-coloring of G is a proper vertex coloring such that there is a vertex in each color class, which is adjacent to at least one vertex in every other color class. Such a vertex is called a color-dominating vertex. The b-chromatic number of G is the largest k such that there is a b-coloring of G by k colors.
Moreover, if for every integer k, between chromatic number and b-chromatic number, there exists a b-coloring of G by k colors, then G is b-continuous. Determining the b-chromatic number of a graph G and the decision whether the given graph G is b-continuous or not is NP-hard. Therefore, it is interesting to find new results on b-colorings and b-continuity for special graphs.
In this thesis, for several graph classes some exact values as well as bounds of the b-chromatic number were ascertained. Among all we considered graphs whose independence number, clique number, or minimum degree is close to its order as well as bipartite graphs. The investigation of bipartite graphs was based on considering of the so-called bicomplement which is used to determine the b-chromatic number of special bipartite graphs, in particular those whose bicomplement has a simple structure. Then we studied some graphs whose b-chromatic number is close to its t-degree.
At last, the b-continuity of some graphs is studied, for example, for graphs whose b-chromatic number was already established in this thesis. In particular, we could prove that Halin graphs are b-continuous.
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Aspects of the Continuity of Serbian ChantPetrović, Danica 07 February 2020 (has links)
No description available.
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Kontinuität und Wandel in der Komposition aus der Sicht eines KomponistenObst, Michael 01 September 2020 (has links)
No description available.
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On b-colorings and b-continuity of graphsAlkhateeb, Mais 28 June 2012 (has links)
A b-coloring of G is a proper vertex coloring such that there is a vertex in each color class, which is adjacent to at least one vertex in every other color class. Such a vertex is called a color-dominating vertex. The b-chromatic number of G is the largest k such that there is a b-coloring of G by k colors.
Moreover, if for every integer k, between chromatic number and b-chromatic number, there exists a b-coloring of G by k colors, then G is b-continuous. Determining the b-chromatic number of a graph G and the decision whether the given graph G is b-continuous or not is NP-hard. Therefore, it is interesting to find new results on b-colorings and b-continuity for special graphs.
In this thesis, for several graph classes some exact values as well as bounds of the b-chromatic number were ascertained. Among all we considered graphs whose independence number, clique number, or minimum degree is close to its order as well as bipartite graphs. The investigation of bipartite graphs was based on considering of the so-called bicomplement which is used to determine the b-chromatic number of special bipartite graphs, in particular those whose bicomplement has a simple structure. Then we studied some graphs whose b-chromatic number is close to its t-degree.
At last, the b-continuity of some graphs is studied, for example, for graphs whose b-chromatic number was already established in this thesis. In particular, we could prove that Halin graphs are b-continuous.:Contents
1 Introduction
2 Preliminaries
2.1 Basic terminology
2.2 Colorings of graphs
2.2.1 Vertex colorings
2.2.2 a-colorings
3 b-colorings
3.1 General bounds on the b-chromatic number
3.2 Exact values of the b-chromatic number for special graphs
3.2.1 Graphs with maximum degree at most 2
3.2.2 Graphs with independence number close to its order
3.2.3 Graphs with minimum degree close to its order
3.2.4 Graphs G with independence number plus clique number at most number of vertices
3.2.5 Further known results for special graphs
3.3 Bipartite graphs
3.3.1 General bounds on the b-chromatic number for bipartite graphs
3.3.2 The bicomplement
3.3.3 Bicomplements with simple structure
3.4 Graphs with b-chromatic number close to its t-degree
3.4.1 Regular graphs
3.4.2 Trees and Cacti
3.4.3 Halin graphs
4 b-continuity
4.1 b-spectrum of special graphs
4.2 b-continuous graph classes
4.2.1 Known b-continuous graph classes
4.2.2 Halin graphs
4.3 Further graph properties concerning b-colorings
4.3.1 b-monotonicity
4.3.2 b-perfectness
5 Conclusion
Bibliography
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Progression of externalizing disorders into anxiety disorders: Longitudinal transitions in the first three decades of lifeKnappe, Susanne, Martini, Julia, Muris, Peter, Wittchen, Hans-Ulrich, Beesdo-Baum, Katja 28 March 2023 (has links)
Background:
There is a notable comorbidity between externalizing disorders and anxiety disorders, which may be explained by the co-occurrence of two prevalent early-onset disorders, by shared vulnerability and risk factors, or as evidence that one disorder group might be causally related to the other.
Aim:
To investigate the longitudinal trajectories of externalizing disorders, their interplay with anxiety disorders, and putative predictors for symptom progression in youth.
Methods:
1053 adolescents (14–17 years) from the general population were assessed at baseline and prospectively at 2, 4, and 10-year follow-up using a standardized interview of mental disorders (DIA-X/M-CIDI) to assess “early” (oppositional-defiant disorder, conduct disorder, ADHD) and “late” (antisocial behavior, substance use disorders) externalizing disorders as well as anxiety disorders. Longitudinal associations and predictors for symptom progression were examined using Kaplan-Meier-analyses.
Results:
Lifetime prevalence of early externalizing disorders were 9.1% and 6.4% among those with and without any anxiety disorder. A late externalizing disorder was reported by 50.3% of those with an early externalizing disorder and in 26.6% of those with any anxiety disorder. Both early (HR: 1.5, 95%CI: 1.0–2.3) and late externalizing disorders (HR: 2.1, 95%CI: 1.7–2.6) were associated with incident anxiety disorders. Higher parental rejection, lower volitional inhibition, and higher volitional avoidance predicted incident anxiety disorders among those with early externalizing disorders.
Discussion:
Early externalizing disorders likely follow a homotypic continuity (to late externalizing disorders) and/or a heterotypic continuity to anxiety disorders, and thus appear as a useful target for prevention and early intervention.
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The Darwinian revolution as a knowledge reorganizationZacharias, Sebastian 24 February 2015 (has links)
Die Dissertation leistet drei Beiträge zur Forschung: (1) Sie entwickelt ein neuartiges vierstufiges Modell wissenschaftlicher Theorien. Dieses Modell kombiniert logisch-empiristische Ansätze (Carnap, Popper, Frege) mit Konzepten von Metaphern & Narrativen (Wittgenstein, Burke, Morgan), erlaubt so deutlich präzisiere Beschreibungen wissenschaftlicher Theorien bereit und löst/mildert Widersprüche in logisch-empiristischen Modellen. (Realismus vs. Empirismus, analytische vs. synthetische Aussagen, Unterdeterminiertheit/ Holismus, wissenschaftliche Erklärungen, Demarkation) (2) Mit diesem Modell gelingt ein Reihenvergleich sechs biologischer Theorien von Lamarck (1809), über Cuvier (1811), Geoffroy St. Hilaire (1835), Chambers (1844-60), Owen (1848-68), Wallace (1855/8) zu Darwin (1859-1872). Dieser Vergleich offenbart eine interessante Asymmetrie: Vergleicht man Darwin mit je einem Vorgänger, so bestehen zahlreiche wichtige Unterschiede. Vergleicht man ihn mit fünf Vorgängern, verschwinden diese fast völlig: Darwins originärer Beitrag zur Revolution in der Biologie des 19.Jh ist klein und seine Antwort nur eine aus einer kontinuierlichen Serie auf die empirischen Herausforderungen durch Paläontologie & Biogeographie seit Ende des 18. Jh. (3) Eine gestufte Rezeptionsanalyse zeigt, warum wir dennoch von einer Darwinschen Revolution sprechen. Zuerst zeigt eine quantitative Analyse der fast 2.000 biologischen Artikel in Britannien zwischen 1858 und 1876, dass Darwinsche Konzepte zwar wichtige Neuerungen brachten, jedoch nicht singulär herausragen. Verlässt man die Biologie und schaut sich die Rezeption bei anderen Wissenschaftlern und gebildeten Laien an, wechselt das Bild: Je weiter man aus der Biologie heraustritt, desto weniger Ebenen biologischen Wissens kennen die Rezipienten und desto sichtbarer wird Darwins Beitrag. Schließlich findet sich sein Beitrag in den abstraktesten Ebenen des biologischen Wissens: in Narrativ und Weltbild – den Ebenen die Laien rezipieren. / The dissertation makes three contributions to research: (1) It develops a novel 4-level-model of scientific theories which combines logical-empirical ideas (Carnap, Popper, Frege) with concepts of metaphors & narratives (Wittgenstein, Burke, Morgan), providing a new powerful toolbox for the analysis & comparison of scientific theories and overcoming/softening contradictions in logical-empirical models. (realism vs. empiricism, analytic vs. synthetic statements, holism, theory-laden observations, scientific explanations, demarcation) (2) Based on this model, the dissertation compares six biological theories from Lamarck (1809), via Cuvier (1811), Geoffroy St. Hilaire (1835), Chambers (1844-60), Owen (1848-68), Wallace (1855/8) to Darwin (1859-1872) and reveals an interesting asymmetry: Compared to any one of his predecessors, Darwins theory appears very original, however, compared to all five predecessor theories, many of these differences disappear and it remains but a small original contribution by Darwin. Thus, Darwin’s is but one in a continuous series of responses to the challenges posed to biology by paleontology and biogeography since the end of the 18th century. (3) A 3-level reception analysis, finally, demonstrates why we speak of a Darwinian revolution nevertheless. (i) A quantitative analysis of nearly 2.000 biological articles reveals that Darwinian concepts where indeed an important theoretical innovation – but definitely not the most important of the time. (ii) When leaving the circle of biology and moving to scientists from other disciplines or educated laymen, the landscape changes. The further outside the biological community, the shallower the audience’s knowledge – and the more visible Darwin’s original contribution. After all, most of Darwin’s contribution can be found in the narrative and worldview of 19th century biology: the only level of knowledge which laymen receive.
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