KPD und SPD - zwei Linien der Wohnungspolitik in den zwanziger Jahren

Wissenschaftliches Kolloquium vom 5. bis 7. Juli 1983 in Weimar an der Hochschule für Architektur und Bauwesen zum Thema: 'Das Bauhauserbe und die gegenwärtige Entwicklung der Architektur : zum 100. Geburtstag von Walter Gropius

Die empirische Evidenz der Handlungsfelder von LehrerInnen in den KMK-Empfehlungen zu den Bildungs- und Fachwissenschaften

Hauptaufgabe der universitären LehrerInnenbildung ist die Ausbildung angehender LehrerInnen im Hinblick auf ihre berufliche Handlungskompetenz. Zu erreichende Kompetenzstandards werden in den Empfehlungen der Kultusministerkonferenz zu den Bildungswissenschaften (2004) und den Fachwissenschaften (2008) beschrieben. Als Basis für die Festlegung von Standards für die theoretischen und praktischen Ausbildungsabschnitte, wird in den Empfehlungen für die Bildungswissenschaften eine Differenzierung in die Handlungsfelder \u27Unterrichten\u27, \u27Erziehen\u27, \u27Beurteilen\u27 und \u27Innovieren\u27 vorgenommen. [...] Die Verbindlichkeit der Übernahme der Kompetenzformulierungen durch die Länder und die augenscheinliche Plausibilität der Struktur der beruflichen Handlungsfelder, die als Bezugspunkt der Kompetenzstandards dient, führen dennoch zu einer starken Orientierung der universitären LehrerInnenbildung an den formulierten Standards. (DIPF/Orig.

Die Idee des "Großen Bauens"

Wissenschaftliches Kolloquium vom 27. bis 29. Juni 1979 in Weimar an der Hochschule für Architektur und Bauwesen zum Thema: '60 Jahre Gründung Bauhaus

Evolution of Sociality: mechanisms and dynamics of social behavior in spiders

Most animals live solitarily, but for some species the benefits of group living outweigh the costs and social communities have evolved. Truly social societies are characterized by cooperation in tasks like foraging, predator defense and brood care. In the most extreme cases, non-reproducing individuals act as helpers and provision offspring of reproducing individuals at the cost of their own reproductive success. This alloparental care is attributed to kin selection that provides the helpers with inclusive fitness benefits. However, how reproductive role is determined and in which ways virgin helpers in a group benefit the community is not always well understood. Spiders are known to be generalist hunters, which in many cases do not shy away from cannibalism. Thus, most spiders live solitarily. However, in a few species a permanently social lifestyle has evolved in which individuals live together throughout their life, providing an intriguing case of social evolution. These spider communities are characterized by lack of premating dispersal leading to extreme inbreeding, by reproductive skew, in which only a proportion of females reproduce and by cooperative breeding of the reproducing females. It has been assumed that the large proportion of virgin females act as helpers not only in foraging and web maintenance but also during brood care. In the social spider Stegodyphus dumicola brood care involves the intensive task of regurgitation feeding, at which mothers regurgitate their own liquefied body tissue. At the end of brood care, the offspring sucks the mothers dry during matriphagy, leading to the death of brood caring females and a semelparous lifestyle. In the closely related solitarily breeding Stegodyphus lineatus virgin females do not provide brood care. The ability of virgin females in S. dumicola to care for offspring would thus depict an adaptation to sociality and cooperative breeding. I therefore aimed to clarify the role and significance of virgin females in colonies of social spiders and furthermore investigated a possible mechanism of how reproductive role within a colony is determined. I investigated whether there is differential task participation in a non-reproductive task and the task of brood care among reproducing mothers and virgin females (helpers) in Stegodyphus dumicola. The study provides explicit evidence that brood care – including egg sac care, regurgitation feeding and matriphagy – is performed by mothers as well as by virgin helpers. Virgin females in a colony can thus rightfully be termed allomothers. However, the task participation differed between the reproductive states. While mothers engaged more often in brood care, virgin females were more active in foraging. However, the active provisioning of offspring by the virgin females decreases the motherly workload as is suggested by the extended brood care period in comparison to solitary breeders. The observations on virgin allomaternal care are supported by histological studies on the midgut tissue of brood caring females, which revealed that mothers and virgin helpers undergo comparable morphological changes in preparation of regurgitation feeding. The changes in virgin females correlate to ovarian development that might depict an internal maturation process which sets virgin females in the right state to provide care. The morphological changes in mothers and virgin helpers of S. dumicola are less comprehensive than in the solitarily breeding S. lineatus mothers. This indicates that cooperatively caring females are able to save on their resources, provision offspring for longer and thus are probably able to increase survival of the brood by an extended care period. A surprising consequence of cooperative brood care is the ability of mothers to produce a second viable egg sac, even when the first brood is successful. Mothers of the cooperative breeding S. dumicola can thus depart from the strictly semelparous lifestyle and instead invest part of their resources in a second clutch. This finding identified a new way of how cooperative breeding enhances breeding success of reproducers and thus inclusive fitness for helpers as well, thus adding to the benefits of allomaternal care. Virgin females did not store significantly lower amounts of lipids in their midgut tissue than mothers, raising the question of how much reproductive role of females is determined by competition for resources during growth, as often assumed. Another possible determinant of female reproductive skew is the characteristic male scarcity in spider colonies, with only about 12 percent of spiders being male. Males are assumed to mature early within a few days and die early, thus leaving late maturing females unmated due to lack of mating partners. However, my studies provided evidence that male maturation is more skewed than expected and males might survive several months. Subadult females did not accelerate molting when an adult male was present, which could further indicate, that male presence is not a limiting factor on reproduction in males. Furthermore, males are able copulate with up to 16 females and did not show e preference for large females during mating trials. Males are thus able to fertilize all females, provided all females mature in time. I therefore suggest, that male scarcity is not major determinant of reproductive skew in females, especially in small and middle-sized colonies in which female maturation might only be moderately skewed. My studies were able to demonstrate the meaning of the large proportion of unmated females in a colony of the social spider S. dumicola. Virgin helpers support mothers during brood care and thus do not only enhance the brood care period but facilitate mothers to produce multiple clutches. Virgin females are able to care as they undergo similar morphological changes as mothers’ do. This seems to be facilitated by an internal maturation process, indicated by ovarian development and oviposition by virgin females, both of which has never been observed in virgins of the subsocial species. How reproductive role is determined remains unclear, but I was able to exclude male scarcity as a major factor influencing reproductive skew.Dauerhaftes Zusammenleben in sozialen Gemeinschaften und Kooperation sind seltene Phänomene bei Spinnen, welche sonst als kannibalistische Einzelgänger gelten. Permanent sozial lebende Spinnen bilden damit eine geeignete Basis, um zu untersuchen, wie Sozialleben evolutionär entstanden ist und welche Mechanismen es bestimmen und steuern. Das intensive Brutpflegeverhalten der Spinnenweibchen gilt dabei als Schlüsselkomponente auf dem Weg zur Sozialität. Mit Hilfe morphologischer und verhaltensbiologischer Ansätze untersucht diese Arbeit das kooperative Brutpflegeverhalten der sozialen Spinne Stegodyphus dumicola und erörtert dabei insbesondere die Rolle virginer Weibchen bei der Jungenaufzucht. Die Ergebnisse der Studie tragen dazu bei die Evolution der Sozialität innerhalb der Spinnen und die aus der sozialen Lebensweise hervorgehenden Konzequenzen besser zu verstehen

Local theory of projection methods for Cauchy singular integral equations on an interval

We consider a finite section (Galerkin) and a collocation method for Cauchy singular integral equations on the interval based on weighted Chebyshev polymoninals, where the coefficients of the operator are piecewise continuous. Stability conditions are derived using Banach algebra techniques, where also the system case is mentioned. With the help of appropriate Sobolev spaces a result on convergence rates is proved. Computational aspects are discussed in order to develop an effective algorithm. Numerical results, also for a class of nonlinear singular integral equations, are presented

Local theory of a collocation method for Cauchy singular integral equations on an interval

We consider a collocation method for Cauchy singular integral equations on the interval based on weighted Chebyshev polynomials , where the coefficients of the operator are piecewise continuous. Stability conditions are derived using Banach algebra methods, and numerical results are given

On polynomial collocation for Cauchy singular integral equations with fixed singularities

In this paper we consider a polynomial collocation method for the numerical solution of Cauchy singular integral equations with fixed singularities over the interval, where the fixed singularities are supposed to be of Mellin convolution type. For the stability and convergence of this method in weighted L2 spaces, we derive necessary and sufficient conditions

Properties and numerical solution of an integral equation system to minimize airplane drag for a multiwing system

We consider an open multiwing system, composed of N 2 disjoint openplane curves, not necessarily symmetric, and examine the corresponding (con-strained) induced drag minimization problem. To this end, we first derive theassociated Euler-Lagrange system of equations, which is then reduced to anequivalent system of Cauchy singular integral equations. By generalizing a pre-vious approach of ours for the case of a single open wing, we obtain existenceand uniqueness results for the problem solution in a product of weighted Sobolevtype spaces. This system is then solved by applying to it a collocation-quadraturemethod. For this, we prove stability and derive corresponding error estimates.Finally, to test the efficiency of the proposed numerical method, we apply it tosome multiwing system