1,711 research outputs found
Inverting the regulatory rules? Optimizing airport regulation to account for commercial revenues
This paper analyzes the role of commercial revenues in today's airport regulatory system. We find that the current regulatory regime only partially achieves core aims such as welfare maximization. After highlighting instances in which airport price regulation is not economically justified, we explore the potential for airports to exercise market power in the commercial sector. In certain circumstances, we advocate the introduction of an 'inverted' dual till system under which commercial as opposed to aviation revenues are the focus of price regulation. The suitability of such a system varies from airport to airport, however, depending on various factors, such as the airport's competitive environment and the presence of capacity constraints. --Airport regulation,non-aviation revenues,price differentiation,single till,dual till
Task dependence of U.S. service offshoring patterns
This work offers new insights into the determinants of service offshoring
across countries and across service industries. Combining different data
sources over the 2006-2009 period, I find that certain country characteristics
affect offshoring costs for all services, while the effects of other
characteristics depend on the coordination requirements of the respective
service industry. The results from a zero-inflated Poisson pseudomaximum
likelihood estimation indicate that the effects of a membership in NAFTA, and
a common colonial past on service offshoring patterns depend on the task
content of the services. These results are robust to the control for
unobservable country-level heterogeneity. The quality of legal institutions, a
common legal origin, geographic distance, and time zone differences influence
offshoring patterns identically across all service industries
Die Tätigkeit der Gruppe Hannes Meyer in der UdSSR in den Jahren 1930 bis 1937
Wissenschaftliches Kolloquium vom 27. bis 29. Oktober 1976 in Weimar an der Hochschule für Architektur und Bauwesen zum Thema: '50 Jahre Bauhaus Dessau
Cell death and cytokine-mediated inflammatory responses to glucose deprivation in cancer cells
[eng] Metabolic alterations in cancer cells are primarily caused by oncogenic mutations and cancer cells are more dependent on glucose compared to non-transformed tissue. Targeting the cancer metabolism opens up a new strategy for anti-cancer therapy. In order to make drugs more efficient and applicable in the clinic, it is necessary to fully investigate the cancer cell metabolism, especially of how cancer cells die upon glucose deprivation and more importantly, the consequences on the surrounding tissue when modifying or interfering with the metabolism.
The unfolded protein response (UPR) is an intracellular stress response which is induced upon glucose deprivation. The activation of the three branches of the UPR facilitates pro-survival responses, however, chronic exposure to intra- or extracellular stress results in a switch towards a pro-death UPR response. The UPR is also described to be involved in pro-inflammatory responses due to the induction of cytokines and chemokines in several cell lines. Therefore, the release of cytokines upon glucose deprivation could facilitate the infiltration or exclusion of immune cells.
We hypothesized that cancer cells die in an UPR dependent manner and that cancer cells release inflammatory cytokines upon glucose deprivation, which promote the infiltration of immune cells.
We found that HeLa cells exposed to glucose deprivation, died in a TRAIL receptor 1 (DR4) and 2 (DR5) dependent manner, which was mediated by the activation transcription factor 4 (ATF4).
Furthermore, we found the release of pro-tumorigenic cytokines such as interleukin-8 (IL-8), interleukin-6 (IL-6) and the leukemia inhibitory factor (LIF) from glucose deprived cancer cells as well as upon treatment with anti-metabolic drugs. We found that IL 6 and IL-8 but not LIF were regulated by ATF4 and p65 upon glucose deprivation. Moreover, the conditioned media of glucose deprived A549 promoted the migration of macrophage-like THP-1 cells as well as primary B cells and neutrophils isolated from human blood.
These findings are important, since interfering with the cancer metabolism by using anti metabolic drugs could suppress the anti-tumorigenic effect of these drugs by promote pro-tumorigenic responses
The biomechanical importance of the scaphoid-centrale fusion during simulated knuckle-walking and its implications for human locomotor evolution
© 2020, The Author(s). Inferring the locomotor behaviour of the last common ancestor (LCA) of humans and African apes is still a divisive issue. An African great-ape-like ancestor using knuckle-walking is still the most parsimonious hypothesis for the LCA, despite diverse conflicting lines of evidence. Crucial to this hypothesis is the role of the centrale in the hominoid wrist, since the fusion of this bone with the scaphoid is among the clearest morphological synapomorphies of African apes and hominins. However, the exact functional significance of this fusion remains unclear. We address this question by carrying out finite element simulations of the hominoid wrist during knuckle-walking by virtually generating fused and unfused morphologies in a sample of hominoids. Finite element analysis was applied to test the hypothesis that a fused scaphoid-centrale better withstands the loads derived from knuckle-walking. The results show that fused morphologies display lower stress values, hence supporting a biomechanical explanation for the fusion as a functional adaptation for knuckle-walking. This functional interpretation for the fusion contrasts with the current inferred positional behaviour of the earliest hominins, thus suggesting that this morphology was probably retained from an LCA that exhibited knuckle-walking as part of its locomotor repertoire and that was probably later exapted for other functions
HIV-1-Prävalenz bei Drogentoten in der Bundesrepublik Deutschland sowie im internationalen Vergleich (Stand 31.12.1991)
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