36 resultados para MATURITY
Resumo:
A sediment record from a small lake in the north-eastern part of the Kamchatka Peninsula has been investigated in a multi-proxy study to gain knowledge of Holocene climatic and environmental change. Pollen, diatoms, chironomids and selected geochemical parameters were analysed and the sediment record was dated with radiocarbon. The study shows Holocene changes in the terrestrial vegetation as well as responses of the lake ecosystem to catchment maturity and multiple stressors, such as climate change and volcanic eruptions. Climate change is the major driving force resulting in the recorded environmental changes in the lake, although recurrent tephra deposition events also contributed. The sediment record has an age at the base of about 10,000 cal yrs BP, and during the first 400 years the climate was cold and the lake exhibited extensive ice-cover during winter and relatively low primary production. Soils in the catchment were poor with shrub alder and birches dominating the vegetation surrounding the lake. At about 9600–8900 cal yrs BP the climate was cold and moist, and strong seasonal wind stress resulted in reduced ice-cover and increased primary production. After ca. 8900 cal yrs BP the forest density increased around the lake, runoff decreased in a generally drier climate resulting in decreased primary production in the lake until ca. 7000 cal yrs BP. This generally dry climate was interrupted by a brief climatic perturbation, possibly attributed to the 8.2 ka event, indicating increasingly windy conditions with thick snow cover, reduced ice-cover and slightly elevated primary production in the lake. The diatom record shows maximum thermal stratification at ca. 6300–5800 cal yrs BP and indicates together with the geochemical proxies a dry and slightly warmer climate resulting in a high productive lake. The most remarkably change in the catchment vegetation occurred at ca. 4200 cal yrs BP in the form of a conspicuous increase in Siberian dwarf pine (Pinus pumila), indicating a shift to a cooler climate with a thicker and more long-lasting snow cover. This vegetational change was accompanied by marked shifts in the diatom and chironomid stratigraphies, which are also indicative of colder climate and more extensive ice-cover.
Resumo:
This book provides an international perspective on Public Private Partnerships. Through 21 case studies, it investigates the existing and fast developing body of principles and practices from a wide range of countries and is the first book to bring together leading international academics and practitioners under a common framework that enables convenient cross-country comparisons. The authors focus on the impact of the financial crisis has had on how governments have reviewed and overhauled their PPP policies as they have examined or tested new ways of partnering more effectively, efficiently and sustainably with the private sector.
Readers will be able to gauge the level of maturity of PPP development in the book’s case studies, understand similarities and differences in their practices, and gain useful insights into the regulatory framework and institutional infrastructure in place to support implementation of PPP. Finally, the book offers insights into the future challenges and opportunities that PPP offers stakeholders.
Resumo:
How much should an individual invest in immunity as it grows older? Immunity is costly and its value is likely to change across an organism's lifespan. A limited number of studies have focused on how personal immune investment changes with age in insects, but we do not know how social immunity, immune responses that protect kin, changes across lifespan, or how resources are divided between these two arms of the immune response. In this study, both personal and social immune functions are considered in the burying beetle, Nicrophorus vespilloides. We show that personal immune function declines (phenoloxidase levels) or is maintained (defensin expression) across lifespan in nonbreeding beetles but is maintained (phenoloxidase levels) or even upregulated (defensin expression) in breeding individuals. In contrast, social immunity increases in breeding burying beetles up to middle age, before decreasing in old age. Social immunity is not affected by a wounding challenge across lifespan, whereas personal immunity, through PO, is upregulated following wounding to a similar extent across lifespan. Personal immune function may be prioritized in younger individuals in order to ensure survival until reproductive maturity. If not breeding, this may then drop off in later life as state declines. As burying beetles are ephemeral breeders, breeding opportunities in later life may be rare. When allowed to breed, beetles may therefore invest heavily in "staying alive" in order to complete what could potentially be their final reproductive opportunity. As parental care is important for the survival and growth of offspring in this genus, staying alive to provide care behaviors will clearly have fitness payoffs. This study shows that all immune traits do not senesce at the same rate. In fact, the patterns observed depend upon the immune traits measured and the breeding status of the individual.
Resumo:
Building Information Modelling (BIM) is continuing to evolve and develop as the construction industry progresses towards level 2 maturity. However, one of the core barriers in this progression is the aspect of interoperability between software packages. This research and paper stems from a Knowledge Transfer Partnership (KTP) where both industry and academia come together to address this shortcoming within the sector. One of the core objectives of this partnership and the aim of this study is investigating potential solutions to this barrier, while also developing best working practices to be applied in industry. Using one of the case studies from this partnership (a temporary steel structure), this paper demonstrates a potential solution to addressing interoperability within structural analysis and detailing packages, MasterSeries and Revit respectively. The findings of the research indicate that a process based approach rather than that of additional software coding as being the preferred solution. The results of this preliminary research will aid in the development of the topic of interoperability within the sector, while also developing the knowledge and competencies of the parties within the KTP. The findings are explored further, by providing an overview of the resolution process adopted in this case study, in overcoming the interoperability that arose as the project progressed. It is envisaged that this study will assist the construction sector and its adoption of BIM technologies, while also addressing the critical aspect of operability between software.
Resumo:
PURPOSE: Few studies have examined the impact of long-term treatments or exposures on the development of cataract in maturity-onset animal models. We studied the effect of treatment with D-pantethine and exposure to ultraviolet-B (UVB) radiation on the development of lenticular opacity in the Emory mouse. METHODS: A total of 164 Emory mice were randomized by litter at weaning to exposure to UVB light at 12 mJ/cm(2) for 6 hr/day (UV) or usual room light (A), and within litter, were further randomized to bi-weekly intra-peritoneal injections of 0.8 g/kg pantethine (T) or no treatment (C). Retro illumination lens photos were taken at 2, 4, 6, 8, and 10 months after weaning, and graded in masked fashion. The animals were sacrificed at 10 months and the lenses analyzed for total pantethine and total cysteamine. RESULTS: Lens pantethine and cysteamine levels were significantly (P < 0.001) higher for the T as compared to C litters. Mean cataract grade increased monotonically over time for all four groups. Unadjusted mean grade for the AT group at 8 (1.32) and 10 (1.86) months appeared lower than for the other groups (AC: 2.17, 2.39; UVC: 1.77, 2.40; UVT: 1.88, 2.37). However, the mean grade for the pantethine-treated litters did not differ significantly from the untreated litters except at 2 months (when untreated litters had significantly lower grades), when adjusting for UV treatment, gender and litter effect. No significant difference in cataract score existed between UV-exposed and ambient litters. Mortality was higher among pantethine-treated (hazard ratio = 1.8, p = 0.05) and UV-exposed animals (hazard ratio = 1.8, p = 0. 03) than among the untreated and unexposed litters. CONCLUSION: Significantly increased lens levels of pantethine are achieved with long-term intra-peritoneal dosing. The impact of pantethine on the progression of lenticular opacity in the Emory mouse is less than has been reported in other models. This level of chronic UVB exposure appeared to have no effect on the development of cataract in this model.
Resumo:
An overview of research on the development of the hybrid test method is presented. The maturity of the hybrid test method is mapped in order to provide context to individual research in the overall development of the test method. In the pseudo dynamic (PsD) test method, the equations of motion are solved using a time stepping numerical integration technique with the inertia and damping being numerically modelled whilst restoring force is physically measured over an extended timescale. Developments in continuous PsD testing led to the real-time hybrid test method and geographically distributed hybrid tests. A key aspect to the efficiency of hybrid testing is the substructuring technique where the critical structural subassemblies that are fundamental to the overall response of the structure are physically tested whilst the remainder of the structure whose response can be more easily predicted is numerically modelled. Much of the early research focused on developing the accuracy and efficiency of the test method, whereas more recently the method has matured to a level where the test method is applied purely as a dynamic testing technique. Developments in numerical integration methods, substructuring, experimental error reduction, delay compensation and speed of testing have led to a test method now in use as full-scale real-time dynamic testing method that is reliable, accurate, efficient and cost effective.