40 research outputs found
Cybercities: Mediated Public Open Spaces - A Matter of Interaction and Interfaces.
In the near past, sources of information about public open spaces were: people, the place itself and historical archives. Accordingly, the information could be obtained by interviewing the visitors, by reading some poorly equipped signs on monuments or by research in libraries. Today, a new source appeared: The place itself covers its own information by the mean of the growing of the ICT (Information Communication Technologies). In addition, the information can be personalised in a way each people can access it individually. Ten years ago, a left-over newspaper on a park bench was a compact piece of information. Today, the newspaper resides on a smartphone in our pockets. In the future, the park bench will still be there, but dramatically changed to an IoT (Internet of things) object, bringing information to the people. Therefore, there is the need to re-think the park bench as an interface. A simple, fundamental point is: the quality of the interface rules the quality of the information. With a special focus on the latter, this chapter discusses how the classical model of the city is enhanced with the senseable city concept and how digital information influences, adopts, transforms and re-configures different objects in urban areas
Broad-Spectrum Matrix Metalloproteinase Inhibition Curbs Inflammation and Liver Injury but Aggravates Experimental Liver Fibrosis in Mice
Background Liver fibrosis is characterized by excessive synthesis of extracellular matrix proteins, which prevails over their enzymatic degradation, primarily by matrix metalloproteinases (MMPs). The effect of pharmacological MMP inhibition on fibrogenesis, however, is largely unexplored. Inflammation is considered a prerequisite and important co-contributor to fibrosis and is, in part, mediated by tumor necrosis factor (TNF)-α-converting enzyme (TACE). We hypothesized that treatment with a broad-spectrum MMP and TACE-inhibitor (Marimastat) would ameliorate injury and inflammation, leading to decreased fibrogenesis during repeated hepatotoxin-induced liver injury.Methodology/Principal Findings Liver fibrosis was induced in mice by repeated carbon tetrachloride (CCl4) administration, during which the mice received either Marimastat or vehicle twice daily. A single dose of CCl4was administered to investigate acute liver injury in mice pretreated with Marimastat, mice deficient in Mmp9, or mice deficient in both TNF-α receptors. Liver injury was quantified by alanine aminotransferase (ALT) levels and confirmed by histology. Hepatic collagen was determined as hydroxyproline, and expression of fibrogenesis and fibrolysis-related transcripts was determined by quantitative reverse-transcription polymerase chain reaction. Marimastat-treated animals demonstrated significantly attenuated liver injury and inflammation but a 25% increase in collagen deposition. Transcripts related to fibrogenesis were significantly less upregulated compared to vehicle-treated animals, while MMP expression and activity analysis revealed efficient pharmacologic MMP-inhibition and decreased fibrolysis following Marimastat treatment. Marimastat pre-treatment significantly attenuated liver injury following acute CCl4-administration, whereas Mmp9 deficient animals demonstrated no protection. Mice deficient in both TNF-α receptors exhibited an 80% reduction of serum ALT, confirming the hepatoprotective effects of Marimastat via the TNF-signaling pathway.Conclusions/Significance Inhibition of MMP and TACE activity with Marimastat during chronic CCl4administration counterbalanced any beneficial anti-inflammatory effect, resulting in a positive balance of collagen deposition. Since effective inhibition of MMPs accelerates fibrosis progression, MMP inhibitors should be used with caution in patients with chronic liver diseases
Responses of tree species to a severe fire indicate major structural change to Eucalyptus–Callitris forests
Stand-level variation in evapotranspiration in non-water-limited eucalypt forests
© 2017 Elsevier B.V. To better understand water and energy cycles in forests over years to decades, measurements of spatial and long-term temporal variability in evapotranspiration (Ea) are needed. In mountainous terrain, plot-level measurements are important to achieving this. Forest inventory data including tree density and size measurements, often collected repeatedly over decades, sample the variability occurring within the geographic and topographic range of specific forest types. Using simple allometric relationships, tree stocking and size data can be used to estimate variables including sapwood area index (SAI), which may be strongly correlated with annual Ea. This study analysed plot-level variability in SAI and its relationship with overstorey and understorey transpiration, interception and evaporation over a 670 m elevation gradient, in non-water-limited, even-aged stands of Eucalyptus regnans F. Muell. to determine how well spatial variation in annual Ea from forests can be mapped using SAI. Over the 3 year study, mean sap velocity in five E. regnans stands was uncorrelated with overstorey sapwood area index (SAI) or elevation: annual transpiration was predicted well by SAI (R2 0.98). Overstorey and total annual interception were positively correlated with SAI (R2 0.90 and 0.75). Ea from the understorey was strongly correlated with vapour pressure deficit (VPD) and net radiation (Rn) measured just above the understorey, but relationships between understorey Ea and VPD and Rn differed between understorey types and understorey annual Ea was not correlated with SAI. Annual total Ea was also strongly correlated with SAI: the relationship being similar to two previous studies in the same region, despite differences in stand age and species. Thus, spatial variation in annual Ea can be reliably mapped using measurements of SAI
Changes in evapotranspiration following wildfire in resprouting eucalypt forests
© 2014 John Wiley & Sons, Ltd. Forests that recover from disturbance predominately via vegetative resprouting may be expected to have different catchment water balance dynamics following wildfire than forests recovering from seed. However, the impacts of wildfire on forest water use are largely unknown in resprouting forest types. This is despite their dominance across the majority of southern Australia's forested catchments and the large areas burnt in recent years. We hypothesized that postfire changes in evapotranspiration (Et) would be a function of fire severity and topography and that partitioning of Et would change after fire because of altered stand structure. We tested these hypotheses by monitoring Et and component fluxes across different topographic positions and fire severities in a mixed eucalypt species forest located in water supply catchments for the city of Melbourne. For this forest type, wildfire triggers vegetative resprouting from lignotubers and epicormic shoots on the bole and branches of the overstorey trees, in addition to prolific seedling germination. Monitoring was undertaken over 1-3years following the 2009 Black Saturday wildfires. We found that Et was on average 41% lower in forest burnt at high severity compared with unburnt forest, whereas Et from forest burnt at moderate severity was only 3% lower than unburnt forest over 1-2years postfire but on average 9% higher over 2-3years postfire. Et losses were driven by tree and shrub mortality in conjunction with lower transpiration in surviving trees. Lower Et was partially offset by regenerating seedlings that drove increases in forest floor Et and interception loss. Finally, we found that topography, through its effects on evaporative demand and forest structure, was a strong determinant of total Et but did not affect the nature of postfire recovery
Trends in evapotranspiration and streamflow following wildfire in resprouting eucalypt forests
© 2015 Elsevier B.V. The objective of this study was to estimate the recovery trajectory of evapotranspiration (Et) and streamflow (Q) in resprouting forested catchments following wildfire. Recovery dynamics were assessed in mixed species eucalypt forests in south-eastern Australia which recover from disturbance largely via vegetative resprouting, and to a lesser degree, via seedling recruitment. Changes in Et were evaluated in two ways. Firstly, we developed semi-empirical models of post-fire Et following moderate and high severity wildfire. These models were based on datasets of plot-scale Et, measured within five years post-fire, and published literature on post-fire changes in vegetation structure. Secondly, we analysed long-term Q records (25years) from a mixed species catchment, including a 1-5year period following a predominately moderate severity wildfire. We found that the overall length of recovery time for Et and Q following wildfire was 8-12years, which is much less than for eucalypt forests recovering via seedlings only. This emphasises the importance of functional responses to fire in forest ecosystems as a key driver of the hydrologic resilience of catchments, with resprouting forest types conferring relatively rapid recovery following disturbance. We also found that the recovery trajectory of post-fire Et was dependent on fire severity. Increased Et and consequent declines in Q occurred following moderate severity fire. In contrast, there was no evidence of increased Et following high severity fire. Based on patterns of long-term Q and rainfall observed in a small mixed species catchment, declines in Q due to increased Et following moderate severity wildfire were of similar magnitude to Q declines driven by a drought that coincided with the fire. We conclude that the coincidence of wildfire with drought exacerbates reductions in Q under moderate severity fire, resulting in greater Q declines. This is due to the enhanced rates of Et, primarily driven by regenerating seedlings and higher rates of transpiration from surviving trees
Importance of disturbance history on net primary productivity in the world's most productive forests and implications for the global carbon cycle
Analysis of growth and biomass turnover in natural forests of Eucalyptus regnans, the world's tallest angiosperm, reveals it is also the world's most productive forest type, with fire disturbance an important mediator of net primary productivity (NPP). A comprehensive empirical database was used to calculate the averaged temporal pattern of NPP from regeneration to 250 years age. NPP peaks at 23.1 ± 3.8 (95% interquantile range) Mg C ha-1 year-1 at age 14 years, and declines gradually to about 9.2 ± 0.8 Mg C ha-1 year-1 at 130 years, with an average NPP over 250 years of 11.4 ± 1.1 Mg C ha-1 year-1 , a value similar to the most productive temperate and tropical forests around the world. We then applied the age-class distribution of E. regnans resulting from relatively recent historical fires to estimate current NPP for the forest estate. Values of NPP were 40% higher (13 Mg C ha-1 year-1 ) than if forests were assumed to be at maturity (9.2 Mg C ha-1 year-1 ). The empirically derived NPP time series for the E. regnans estate was then compared against predictions from 21 global circulation models, showing that none of them had the capacity to simulate a post-disturbance peak in NPP, as found in E. regnans. The potential importance of disturbance impacts on NPP was further tested by applying a similar approach to the temperate forests of conterminous United States and of China. Allowing for the effects of disturbance, NPP summed across both regions was on average 11% (or 194 Tg C/year) greater than if all forests were assumed to be in a mature state. The results illustrate the importance of accounting for past disturbance history and growth stage when estimating forest primary productivity, with implications for carbon balance modelling at local to global scales
People with Disabilities’ Needs in Urban Spaces as Challenges Towards a More Inclusive Smart City
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