Stockholm University

About: Stockholm University is a education organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Population & Context (language use). The organization has 21052 authors who have published 62567 publications receiving 2725859 citations. The organization is also known as: University of Stockholm & Stockholms universitet.

Marketing as Value Co-creation Through Network Interaction and Resource Integration

Abstract: This is a theoretical discourse on contributions to the marketing discipline primarily from service-dominant (S-D) logic, relationship marketing, and the many-to-many network approach. The study combines a literature review with theoretical insights. Framed within a relational context it specifically addresses interaction and its role in the co-creation of value through resource integration. As a consequence, the article also deals with elevating midrange theory in the direction of more abstract and general theory, grand theory. The article advances a model and five propositions which outline interaction in a network of parties as the most crucial antecedent to resource integration. The actors involved set up a dialog and transfer knowledge and other resources for organizational learning and resource creation and renewal. Resource integration is generalized to actor-to-actor (A2A) interaction through which the actors link their resources for mutual benefit. The integration assumes that resources can differ in terms of quality and quantity and require complementarities, or can be similar leading to an increase in the joint volume but sometimes to redundancy, or there can be mixed forms. In all of these situations interaction and co-creation in networks strive to improve service systems through a better matching between resources, processes, and outcomes.

The mechanics of sea urchin development, studied by operative methods

Abstract: Summary In the cleavage stages the sea urchin's egg can be divided into five transverse layers, an1, an2, veg1, veg2, and the micromeres (Fig. I). The ectoderm of the pluteus larva is derived from an1+ an2+ veg1, while veg2 gives rise to the secondary mesenchyme, the coelom, and the endoderm. The micromere material migrates into the blastocoele before gastrulation, forming the primary mesenchyme, which produces the skeletal rods. The position uf the skeleton-forming cells and of the rods is determined by the ectoderm. The factors determining the cleavage type of the 16-cell stage (8 meso-, 4 macro-, and 4 micromeres) seem to be (I) progressive changes in the cytoplasm, causing spindles formed a certain time after fertilization to lie in a certain direction, (2) the presence in the vegetative part of the egg of a region of micromere-forming material, and (3) the activation of that material a certain time after fertilization. This leads to partial cleavage of isolated blastomeres, and to whole, intermediate or partial cleavage of fragments of undivided eggs, depending upon the time and plane of isolation. Whole eggs may also show partial cleavage. Differentiation is independent of the type of cleavage which the egg or fragment has undergone. The polarity (animal-vegetative axis) of the egg is fairly stable, since it is not altered by centrifuging or by moderate stretching, and it is more or less retained in fragments. On the other hand, the polarity can be changed both by a greater degree of stretching and by placing animal and vegetative material in atypical relationship to one another. A new axis may then be induced, and the whole polarity may sometimes be reversed. A reversal can be brought about both by vegetative and by animal material. The dorso-ventral axis is less stable, as it adjusts itself in accordance with the direction of stretching (perpendicular to the egg axis), not only to a considerable, but also to a moderate degree of stretching. After considerable stretching or constriction, both of which involve partial physiological isolation, as well as on complete isolation, the dorso-ventral axis is spontaneously reversed in the dorsal half. In right and left halves the dorso-ventral axis is maintained, and the larvae are more or less defective on thecut side. In starfish larvae a similar reversal of the right-left axis may occur in right halves. After isolation animal material will form a considerably enlarged apical tuft and later develop only into ciliated cylinder epithelium. In veg., weg., and the micro-meres, we find the faculty of checking the enlargement of the apical tuft and of causing the formation of stomodaeum, ciliated band, and pavement epithelium out of the animal material. Moreover, veg2 has the faculty of forming endoderm and skeletal cells, and under certain conditions also ectoderm. An endodermization of presumptive ectoderm can also be brought about by veg2, but this power of induction is much stronger in the micromeres. To explain the conditions in the sea urchin's egg we assume an animal and a vegetative gradient, both reaching the opposite pole and progressively diminishing. The animal and the vegetative qualities or forces have to interact in order to bring about normal differentiations, e.g. vegetative influences are necessary for the formation of ciliated band and stomodaeum, animal ones for gastrulation and skeleton formation, and so on. The differentiation depends—within wide limits—upon the relative amounts of animal or vegetative material present. We find an endodermization both when the vegetative material is relatively increased (vegetative halves) and decreased (8 + 2 + 2), provided the decrease is not too extreme. In this last case (8 + 1/2 + 0) the vegetative properties may be suppressed. But thanks to a reconcentration at the poles of fragments, the animal and vegetative forces are often able to express themselves more strongly than would be expected from the prospective significance of the material or from the amounts present (apical tuft and mouth in vegetative halves, ectoderm in isolated veg2, as animal differentiations; skeletal cells in 8 + 4 + 0, 0 + 4 + 0, o +veg2+ o, as vegetative differentiations, and so on). Implanting micromeres of one species into the blastocoele of another, von Ubisch has studied the formation of the skeleton in such germ-layer chimaeras (see the article by von Ubisch in Biological Reviews, vol. 14, 1939, p. 88). The roles of nucleus and cytoplasm in the formation of the skeleton have also been studied in heterosperm merogones (larvae with nucleus of one species and cytoplasm of another). A species character was found to follow the nucleus. Both in the germ-layer chimaeras and in the merogones the conditions are too complicated to allow a conclusion as to any possible role of the cytoplasm.

The Thylakoid FtsH Protease Plays a Role in the Light-Induced Turnover of the Photosystem II D1 Protein

Abstract: The photosystem II reaction center D1 protein is known to turn over frequently. This protein is prone to irreversible damage caused by reactive oxygen species that are formed in the light; the damaged, nonfunctional D1 protein is degraded and replaced by a new copy. However, the proteases responsible for D1 protein degradation remain unknown. In this study, we investigate the possible role of the FtsH protease, an ATP-dependent zinc metalloprotease, during this process. The primary light-induced cleavage product of the D1 protein, a 23-kD fragment, was found to be degraded in isolated thylakoids in the dark during a process dependent on ATP hydrolysis and divalent metal ions, suggesting the involvement of FtsH. Purified FtsH degraded the 23-kD D1 fragment present in isolated photosystem II core complexes, as well as that in thylakoid membranes depleted of endogenous FtsH. In this study, we definitively identify the chloroplast protease acting on the D1 protein during its light-induced turnover. Unlike previously identified membrane-bound substrates for FtsH in bacteria and mitochondria, the 23-kD D1 fragment represents a novel class of FtsH substrate— functionally assembled proteins that have undergone irreversible photooxidative damage and cleavage.

Genetic fine mapping and genomic annotation defines causal mechanisms at type 2 diabetes susceptibility loci

Abstract: We performed fine mapping of 39 established type 2 diabetes (T2D) loci in 27,206 cases and 57,574 controls of European ancestry. We identified 49 distinct association signals at these loci, including five mapping in or near KCNQ1. 'Credible sets' of the variants most likely to drive each distinct signal mapped predominantly to noncoding sequence, implying that association with T2D is mediated through gene regulation. Credible set variants were enriched for overlap with FOXA2 chromatin immunoprecipitation binding sites in human islet and liver cells, including at MTNR1B, where fine mapping implicated rs10830963 as driving T2D association. We confirmed that the T2D risk allele for this SNP increases FOXA2-bound enhancer activity in islet- and liver-derived cells. We observed allele-specific differences in NEUROD1 binding in islet-derived cells, consistent with evidence that the T2D risk allele increases islet MTNR1B expression. Our study demonstrates how integration of genetic and genomic information can define molecular mechanisms through which variants underlying association signals exert their effects on disease.