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Many combinatorial optimization problems on finite graphs can be formulated as conic convex programs, e.g. the stable set problem, the maximum clique problem or the maximum cut problem. Especially NP-hard problems can be written as copositive programs. In this case the complexity is moved entirely into the copositivity constraint.
Copositive programming is a quite new topic in optimization. It deals with optimization over the so-called copositive cone, a superset of the positive semidefinite cone, where the quadratic form x^T Ax has to be nonnegative for only the nonnegative vectors x. Its dual cone is the cone of completely positive matrices, which includes all matrices that can be decomposed as a sum of nonnegative symmetric vector-vector-products.
The related optimization problems are linear programs with matrix variables and cone constraints.
However, some optimization problems can be formulated as combinatorial problems on infinite graphs. For example, the kissing number problem can be formulated as a stable set problem on a circle.
In this thesis we will discuss how the theory of copositive optimization can be lifted up to infinite dimension. For some special cases we will give applications in combinatorial optimization.
An Grundschulen bietet der Klassenrat eine Möglichkeit für Schüler*innen, erste Schritte demokratischen Umgangs zu erlernen oder auch zu vertiefen. Hier lernen sie in einem geschützten Raum sich zu verschiedensten Themen zu äußern, Konflikte lösungsorientiert zu verarbeiten und Verantwortung zu übernehmen. Die hier vorgestellten Materialien sollen bei der Einführung und Durchführung des Klassenrats helfen.
Background: Increasing exposure to engineered inorganic nanoparticles takes actually place in both terrestric and aquatic ecosystems worldwide. Although we already know harmful effects of AgNP on the soil bacterial community, information about the impact of the factors functionalization, concentration, exposure time, and soil texture on the AgNP effect expression are still rare. Hence, in this study, three soils of different grain size were exposed for up to 90 days to bare and functionalized AgNP in concentrations ranging from 0.01 to 1.00 mg/kg soil dry weight. Effects on soil microbial community were quantified by various biological parameters, including 16S rRNA gene, photometric, and fluorescence analyses.
Results: Multivariate data analysis revealed significant effects of AgNP exposure for all factors and factor combinations investigated. Analysis of individual factors (silver species, concentration, exposure time, soil texture) in the unifactorial ANOVA explained the largest part of the variance compared to the error variance. In depth analysis of factor combinations revealed even better explanation of variance. For the biological parameters assessed in this study, the matching of soil texture and silver species, and the matching of soil texture and exposure time were the two most relevant factor combinations. The factor AgNP concentration contributed to a lower extent to the effect expression compared to silver species, exposure time and physico–chemical composition of soil.
Conclusions: The factors functionalization, concentration, exposure time, and soil texture significantly impacted the effect expression of AgNP on the soil microbial community. Especially long-term exposure scenarios are strongly needed for the reliable environmental impact assessment of AgNP exposure in various soil types.
When do anorexic patients perceive their body as too fat? Aggravating and ameliorating factors
(2019)
Objective
Our study investigated body image representations in female patients with anorexia nervosa
and healthy controls using a size estimation with pictures of their own body. We also
explored a method to reduce body image distortions through right hemispheric activation.
Method
Pictures of participants’ own bodies were shown on the left or right visual fields for 130 ms
after presentation of neutral, positive, or negative word primes, which could be self-relevant
or not, with the task of classifying the picture as “thinner than”, “equal to”, or “fatter than”
one’s own body. Subsequently, activation of the left- or right hemispheric through right- or
left-hand muscle contractions for 3 min., respectively. Finally, participants completed the
size estimation task again.
Results
The distorted “fatter than” body image was found only in patients and only when a picture of
their own body appeared on the right visual field (left hemisphere) and was preceded by
negative self-relevant words. This distorted perception of the patients’ body image was
reduced after left-hand muscle contractions (right hemispheric activation).
Discussion
To reduce body image distortions it is advisable to find methods that help anorexia nervosa
patients to increase their self-esteem. The body image distortions were ameliorated after
right hemispheric activation. A related method to prevent distorted body-image representations
in these patients may be Eye Movement Desensitization and Reprocessing (EMDR)
therapy.
Because EU water quality policy can result in infrastructure creation or adaptation at the local level across member states, compliance cases are worth examining critically from a sustainable spatial planning perspective. In this study, the 2000 EU Water Framework Directive’s (WFD) reach to local implementation efforts in average towns and cities is shown through the case study of nonconforming household wastewater infrastructure in the German state of Rhineland Palatinate. Seeing wastewater as a socio-technical infrastructure, we ask how the WFD implementation can be understood in the context of local infrastructure development, sustainability, and spatial planning concepts. In particular, this study examines what compliance meant for the centralization or decentralization of local wastewater infrastructure systems—and the sustainability implications for cities
from those choices.
Die Implementierung eines Klassenrats ist mit der Hoffnung verbunden, die demokratischen Kompetenzen von Schüler*innen zu stärken. Welche Kompetenzen die Teilnehmer*innen mithilfe dieser demokratiepädagogischen Methode tatsächlich erwerben und wie sich der Klassenrat auf die Klassengemeinschaft auswirkt, hat eine empirische Studie1 am Lycée Nic Biever in Dudelange untersucht.
Demokratie lebt von der Beteiligung engagierter Bürger*innen. Hierzu ist es notwendig, Kinder und Jugendliche frühzeitig an demokratische Handlungsweisen heranzuführen. Der demokratiepädagogische Klassenrat bietet vielfältige Chancen, Schüler*innen Partizipationserfahrungen zu eröffnen und ihre demokratischen Kompetenzen zu stärken.
C’est la participation des citoyen(ne)s engagé(e)s qui fait vivre la démocratie. À cette fin, il est nécessaire de familiariser le plus tôt possible les enfants et les adolescents aux méthodes démocratiques. Le conseil de coopération est un outil d’éducation à la démocratie qui offre aux élèves de nombreuses possibilités pour expérimenter la participation et renforcer leurs compétences démocratiques.
Den Klassenrat einführen
(2019)
Bevor eine Einführung des Klassenrats in einer Schulklasse erfolgen kann, sind organisatorische, inhaltliche und methodische Vorbereitungen erforderlich. Der Beitrag gibt Hinweise zur Einführung des Klassenrats und bietet konkrete Methoden, die eine erfolgreiche Implementierung in einer Schulklasse unterstützen.