29 resultados para sonic boom
Resumo:
Energie ist eine der wichtigsten Ressourcen der Gegenwart. Wir nutzen sie täglich zum Heizen, Kochen, Beleuchten, Fortbewegen, Arbeiten. Neben der Endlichkeit der fossilen Energieträger rückten in den letzten Jahren auch die mit den Energieregimen verbundenen Risiken (wieder) vermehrt ins Bewusstsein. Gerade deshalb erlebte besonders die Energiegeschichte zum 20. Jahrhundert jüngst einen Aufschwung. Die einzelnen Beiträge zeichnen dabei nicht nur den ungestillten Energiehunger während des Wirtschaftsbooms nach dem Zweiten Weltkrieg nach, sondern gehen auch den Wurzeln des heutigen Energieregimes im 19. Jahrhundert nach. Thematisiert werden die wichtigsten Triebkräfte der Innovationen in der Wasserkraft, die Entwicklungslinien der Energieverwendung und des Energieverbrauchs im Verkehr und in der Landwirtschaft sowie die Auswirkungen eines mehrtägigen Stromausfalls auf die Gesellschaft.
Resumo:
Ziel der Untersuchung war es, Einflüsse auf den Arbeitsmarkt der Bundesrepublik durch das Anwachsen des Wohlfahrtsstaates zu ermitteln. Zu diesem Zweck wurden zwischen 1981 und 1983 2.171 Männer und Frauen der Geburtskohorten 1929-31, 1939-41 und 1949-51 mit standardisierten Interviews befragt zu ihrem Lebensverlauf, speziell unter den Gesichtspunkten: Soziale Herkunft, Ausbildung, Beschäftigung, Familie, Mobilität. Insbesondere interessierte die Frage nach der Beschäftigung im öffentlichen Dienst oder in der Privatwirtschaft bzw. ob und wann ein Wechsel von einem in den anderen Bereich stattgefunden hat. Einige Ergebnisse: Die Bildungsexpansion in den 70er Jahren führte dazu, daß eine steigende Anzahl von Universitätsabsolventen im öffentlichen Dienst Beschäftigung fand; seit der Stagnation des Wohlfahrtsstaates ab ca. 1980 sind die Beschäftigungschancen für hochqualifizierte Berufsanfänger dort wieder gesunken. In der Privatwirtschaft wird unqualifizierte Beschäftigung durch höher qualifizierte ersetzt, während im öffentlichen Dienst bei geringerem Arbeitsplatzangebot weniger hochqualifizierte Berufsanfänger nachgefragt werden.
Resumo:
The strength of top-down indirect effects of carnivores on plants (trophic cascades) varies greatly and may depend on the identity of the intermediate (herbivore) species. If the effect strength is linked to functional traits of the herbivores then this would allow for more general predictions. Due to the generally sub-lethal effects of herbivory in terrestrial systems, trophic cascades manifest themselves in the first instance in the fitness of individual plants, affecting both their numerical and genetic contributions to the population. We directly compare the indirect predator effects on growth and reproductive output of individual Vicia faba plants mediated by the presence of two aphid species: Acyrtosiphon pisum is characterised by a boom and bust strategy whereby colonies grow fast and overexploit their host plant individual while Megoura viciae appear to follow a more prudent strategy that avoids over-exploitation and death of the host plant.Plants in the field were infested with A. pisum, M. viciae or both and half the plants were protected from predators. Exposure to predators had a strong impact on the biomass of individual plants and the strength of this effect differed significantly between the different herbivore treatments.A. pisum had a greater direct impact on plants and this was coupled with a significantly stronger indirect predator effect on plant biomass.Although the direct impact of predators was strongest on M. viciae, this was not transmitted to the plant level, indicating that the predator-prey interactions strength is not as important as the plant-herbivore link for the magnitude of the indirect predator impact. At the individual plant level, the indirect predator effect was purely due to consumptive effects on herbivore densities with no evidence for increased herbivore dispersal in response to presence of predators. The nature of plant-herbivore interactions is the key to terrestrial trophic cascade strength. The two herbivores that we compared were similar in feeding mode and body size but differed their way how they exploit host plants, which was the important trait explaining the strength of the trophic cascade.
Resumo:
The mammalian Cutl1 gene codes for the CCAAT displacement protein (CDP), which has been implicated as a transcriptional repressor in diverse processes such as terminal differentiation, cell cycle progression, and the control of nuclear matrix attachment regions. To investigate the in vivo function of Cutl1, we have replaced the C-terminal Cut repeat 3 and homeodomain exons with an in-frame lacZ gene by targeted mutagenesis in the mouse. The CDP-lacZ fusion protein is retained in the cytoplasm and fails to repress gene transcription, indicating that the Cutl1(lacZ) allele corresponds to a null mutation. Cutl1 mutant mice on inbred genetic backgrounds are born at Mendelian frequency, but die shortly after birth because of retarded differentiation of the lung epithelia, which indicates an essential role of CDP in lung maturation. A less pronounced delay in lung development allows Cutl1 mutant mice on an outbred background to survive beyond birth. These mice are growth-retarded and develop an abnormal pelage because of disrupted hair follicle morphogenesis. The inner root sheath (IRS) is reduced, and the transcription of Sonic hedgehog and IRS-specific genes is deregulated in Cutl1 mutant hair follicles, consistent with the specific expression of Cutl1 in the progenitors and cell lineages of the IRS. These data implicate CDP in cell-lineage specification during hair follicle morphogenesis, which resembles the role of the related Cut protein in specifying cell fates during Drosophila development.
Resumo:
Extracorporeal shock waves are defined as a sequence of sonic pulses characterized by high peak pressure over 100 MPa, fast pressure rise, and short lifecycle. In the 1980s extracorporeal shock wave lithotripsy (ESWL) was first used for the treatment of urolithiasis. Orthopedic surgeons use extracorporeal shock wave therapy (ESWT) to treat non-union fractures, tendinopathies and osteonecrosis. The first application of ESWT in dermatology was for recalcitrant skin ulcers. Several studies in the last 10 years have shown that ESWT promotes angiogenesis, increases perfusion in ischemic tissues, decreases inflammation, enhances cell differentiation and accelerates wound healing. We successfully treated a non-healing chronic venous leg ulcer with ESWT. Furthermore we observed an improvement of the lymphatic drainage after application of ESWT. We are confident that ESWT is a non-invasive, practical, safe and efficient physical treatment modality for recalcitrant leg ulcers.
Resumo:
Objetivo de esta comunicación es presentar los resultados sobre un análisis realizado en torno a lo que podemos denominar el «paisaje lingüístico hispano virtual» en Washington D.F. Los estudios sobre paisaje lingüístico han experimentado en el último tiempo un verdadero boom, sobre todo como reflejo de la convivencia de diferentes culturas con sus respectivas lenguas y variedades en las urbes del siglo XXI. En efecto: el paisaje lingüístico multilingüe es uno de los aspectos más explotados en trabajos en esta línea teórica. En este estudio el centro de atención no es el paisaje "real", documentado in situ y captado motu propio en instantáneas por nuestros aparatos fotográficos, sino el paisaje lingüístico mediatizado por el ordenador y difundido mediante la World Wide Web. En este sentido, lo que nos interesa es si se ve reflejada y qué manera la hispanidad en Washington D.F. a través del paisaje urbano que nos ofrecen programas especializados como Google Earth y Google Street View. Con este objetivo proponemos un paseo virtual por Washington D.F. y sus diferentes barrios para analizar mediante un estudio de naturaleza cuantitativa y cualitativa, apoyándonos en las herramientas teóricas y metodológicas que ofrecen los estudios de paisaje lingüístico y de la Comunicación Mediada por Ordenadores, de qué manera lo hispano constituye un engranaje del paisaje lingüístico de esta ciudad.
Resumo:
Auch in Deutschland versuchen immer mehr Touristiker vom Pilgerboom zu profitieren. Die neuen Wege werden oft nur wenig genutzt. Wer versteht, was Pilgern ausmacht, kann auch erfolgreich agieren. Auf Basis eines empirischen Forschungsprojektes entfaltet der Beitrag das Spezifikum des Pilgerns als einen bestimmten Erfahrungsmodus: Pilger erfahren sich selbst eingebunden in den Zusammenhang des Seins, einen sie tragenden Grund. Es geht um ein Unverfügbares, dem sie sich überlassen, weil es Gewissheit stiftet. Dies setzt dem touristischen Inszenieren enge Grenzen. Werden diese beachtet, entstehen nachhaltige und erfahrungswirksame Pilgerwege. Schlagworte: Pilgern, Erfahrung, Körper, Natur
Resumo:
Ellis-van Creveld (EvC) syndrome is a human autosomal recessive disorder caused by a mutation in either the EVC or EVC2 gene, and presents with short limbs, polydactyly, and ectodermal and heart defects. The aim of this study was to understand the pathologic basis by which deletions in the EVC2 gene lead to chondrodysplastic dwarfism and to describe the morphologic, immunohistochemical, and molecular hallmarks of EvC syndrome in cattle. Five Grey Alpine calves, with a known mutation in the EVC2 gene, were autopsied. Immunohistochemistry was performed on bone using antibodies to collagen II, collagen X, sonic hedgehog, fibroblast growth factor 2, and Ki67. Reverse transcription polymerase chain reaction was performed to analyze EVC1 and EVC2 gene expression. Autopsy revealed long bones that were severely reduced in length, as well as genital and heart defects. Collagen II was detected in control calves in the resting, proliferative, and hypertrophic zones and in the primary and secondary spongiosa, with a loss of labeling in the resting zone of 2 dwarfs. Collagen X was expressed in hypertrophic zone in the controls but was absent in the EvC cases. In affected calves and controls, sonic hedgehog labeled hypertrophic chondrocytes and primary and secondary spongiosa similarly. FGF2 was expressed in chondrocytes of all growth plate zones in the control calves but was lost in most EvC cases. The Ki67 index was lower in cases compared with controls. EVC and EVC2 transcripts were detected. Our data suggest that EvC syndrome of Grey Alpine cattle is a disorder of chondrocyte differentiation, with accelerated differentiation and premature hypertrophy of chondrocytes, and could be a spontaneous model for the equivalent human disease.
Resumo:
The recent increase in prices and production of quinoa have had important effects on the employment structures and livelihoods of rural communities in the Nor Lipez Province (Bolivia). The "quinoa boom" resulted in significant changes in household incomes and in gender roles in the context of increasing market integration. The nature of these changes however is not easy to grasp, as new official narratives on gender and on traditional systems of labour divisions and shared access to land have surfaced since the election of Evo Morales (2006) and the adoption of a new constitution (2009). Furthermore, rural employment is found to be much more diverse than the term suggests. Women have always participated in the production of quinoa when it was widely considered as a subsistence crop. Our research takes place in the Nor Lipez Province, Bolivia with exploratory studies that were conducted in January and February 2015 in 8 rural communities of quinoa producers. Preliminary results suggest positive effects for local women in that they managed to earn additional income which might have contributed to their empowerment. This article will present both preliminary results, challenges for gender-oriented research in Bolivia and the methodology aiming to capture changes at the individual, the household and the community level through a survey that will be conducted from September to November 2015 in 500 households.
Resumo:
Climate change, declines in biodiversity, increasing consumption of resources, urbanisation, urban sprawl and demographic change continue to challenge theregions of Europe. In response to these processes of regional and global change, there has been an unmistakeable boom in parks in Europe since the 1990s. Morethan a fifth of the continent is now protected using designations such as regionalnature parks, national parks, UNESCO Biosphere Reserves and World Heritagesites. The responsibilities of these areas are usually diverse and, in addition tonature protection and the conservation of cultural landscapes, increasingly involvethe promotion of sustainable development. In the 22 chapters of this volume, 28 authors from all over Europe analyse and comment on experiences of tackling the challenges of regional and global changein parks. They illustrate discussions with selected case studies and deal with keyissues of current protected area policy: How do parks address the pending challengesand what successes have they had thus far? What pioneering approaches are there in spatial planning and regional development? Which forms of park managementand governance are most promising? This informative and well-illustratedbook also considers which tasks will be assumed by parks in the future and whatroles parks may play in the debate concerning transformations required to promotesustainability in Europe.
Resumo:
Medulloblastoma (MB) is the most common malignant brain tumor in childhood and represents the main cause of cancer-related death in this age group. The phosphoinositide 3-kinase (PI3K) pathway has been shown to play an important role in the regulation of medulloblastoma cell survival and proliferation, but the molecular mechanisms and downstream effectors underlying PI3K signaling still remain elusive. The impact of RNA interference (RNAi)-mediated silencing of PI3K isoforms p110α and p110δ on global gene expression was investigated by DNA microarray analysis in medulloblastoma cell lines. A subset of genes with selectively altered expression upon p110α silencing in comparison to silencing of the closely related p110δ isoform was revealed. Among these genes, the leukemia inhibitory factor receptor α (LIFR α) was validated as a novel p110α target in medulloblastoma. A network involving c-Myc and miR-125b was shown to be involved in the control of LIFRα expression downstream of p110α. Targeting the LIFRα by RNAi, or by using neutralizing reagents impaired medulloblastoma cell proliferation in vitro and induced a tumor volume reduction in vivo. An analysis of primary tumors revealed that LIFRα and p110α expression were elevated in the sonic hedgehog (SHH) subgroup of medulloblastoma, indicating its clinical relevance. Together, these data reveal a novel molecular signaling network, in which PI3K isoform p110α controls the expression of LIFRα via c-Myc and miR-125b to promote MB cell proliferation.
Resumo:
Medulloblastoma is the most common malignant childhood brain tumor and is associated with a poor outcome. There is an urgent need to develop novel targeted therapeutic approaches for medulloblastoma, which will arise from an enhanced understanding of the disease at the molecular level. Medulloblastoma has been recognized to be a heterogeneous disease, and no recurrent cancer gene mutations have been found, although many of the mutations described so far affect key intracellular signaling pathways, such as sonic hedgehog (SHH) and Wnt/β-catenin. The PI3K/AKT/mTOR (PAM) signaling pathway controls key cellular responses, such as cell growth and proliferation, survival, migration and metabolism. Over the last decades, it has been recognized that this intracellular signaling pathway is frequently activated by genetic and epigenetic alterations in malignant brain tumors, including medulloblastoma. Clinical trials have started to evaluate the safety and efficacy of agents targeting this pathway in malignant brain tumors. Due to the complexity of the PAM signaling pathway, there remain significant difficulties in the development of novel therapeutic approaches. The future challenges in developing effective treatments for cancer patients include the development of predictive biomarkers and combinatorial approaches to effectively target multiple signal transduction pathways. In this review article, we will summarize the current knowledge about the role of PAM signaling in medulloblastoma and discuss the strategies that are currently being evaluated with targeted agents against this pathway.
Resumo:
With a boom in the usage of mobile devices for traffic-heavy applications, mobile networks struggle to deliver good performance while saving resources to support more users and save on costs. In this paper, we propose enhanced strategies for the preemptive migration of content stored in Information-Centric Networking caches at the edge of LTE mobile networks. With such strategies, the concept of content following the users interested in it becomes a reality and content within caches is more optimized towards the requests of nearby users. Results show that the strategies are feasible, efficient and, when compared to default caching strategies, ensure that content is delivered faster to end users while using bandwidth and storage resources more efficiently at the core of the network.