998 resultados para notation composition
Resumo:
Despite plant secondary metabolites being major determinants of species interactions and ecosystem processes, their role in the maintenance of biodiversity has received little attention. In order to investigate the relationship between chemical and biological diversity in a natural ecosystem, we considered the impact of chemical diversity in individual Scots pine trees (Pinus sylvestris) on species richness of associated ground vegetation. Scots pine trees show substantial genetically determined constitutive variation between individuals in concentrations of a group of secondary metabolites, the monoterpenes. When the monoterpenes of particular trees were assessed individually, there was no relationship with species richness of associated ground flora. However, the chemical diversity of monoterpenes of individual trees was significantly positively associated with the species richness of the ground vegetation beneath each tree, mainly the result of an effect among the non-woody vascular plants. This correlation suggests that the chemical diversity of the ecosystem dominant species has an important role in shaping the biodiversity of the associated plant community. The extent and significance of this effect, and its underlying processes require further investigation.
Resumo:
Electroless Ni–P (EN) and composite Ni–P–SiC (ENC) coatings were developed on cast aluminium alloy substrate, LM24. The coating phase composition, microstructure and microhardness were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester, respectively, on as-plated and heat-treated specimens. The original microstructure of the Ni–P matrix is not affected by the inclusion of the hard particles SiC. No formation of Ni–Si phase was observed up to 500 °C of heat treatment. The microhardness is increased on incorporation of SiC in Ni–P matrix. The hardening mechanism is the formation of intermetallic phase Ni3P on annealing at elevated temperature.
Resumo:
Electroless Ni-P (EN) and composite Ni-P-SiC (ENC) coatings were developed on cast aluminium alloy, LM24. The coating phase composition, microstructure and microhardness were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester, respectively, on as-plated and heat-treated specimens. The original microstructure of the Ni-P matrix is not affected by the inclusion of the hard particles SiC. No formation of Ni-Si phase was observed upto 500°C of heat treatment. The microhardness is increased on incorporation of SiC in Ni-P matrix. The hardening mechanism is the formation of intermetallic phase Ni3P on annealing at elevated temperature. Overall, the composite coating (ENC) was found to be superior as compared to particles free (EN) coating in both as-deposited and heat-treated conditions.
Resumo:
Worldwide, the building sector requires the production of 4 billion tonnes of cement annually, consuming more than 40% of global energy. Alkali activated “cementless” binders have recently emerged as a novel eco-friendly construction material with a promising potential to replace ordinary Portland cement. These binders consist of a class of inorganic polymer formed mainly by the reaction between an alkaline solution and an aluminosilicate source. Precursor materials for this reaction can be found in secondary material streams from different industrial sectors, from energy to agro-alimentary. However, the suitability of these materials in developing the polymerisation reaction must be assessed through a detailed chemical and physical characterisation, ensuring the availability of required chemical species in the appropriate quantity and physical state. Furthermore, the binder composition needs to be defined in terms of proper alkali activation dosages, water content in the mix, and curing conditions. The mix design must satisfy mechanical requirements and compliance to desired engineering properties (workability, setting time) for ensuring the suitability of the binder in replacing Portland cement in concrete applications. This paper offers a structured approach for the development of secondary material-based binders, from their identification to mix design and production procedure development. Essential features of precursor material can be determined through chemical and physical characterisation methods and advanced microscope techniques. Important mixing parameters and binder properties requirements are examined and some examples of developed binders are reported.
Resumo:
The research presented here is product of a practice-based process that primarily generates knowledge through collaboration and exchange in performance situations. This collaboration and exchange with various musicians over a period of five years that constitutes a body of practice that is here reflected upon. The paper focuses on non-instructional graphic scores and presents some insights based on performances of works by the author. We address how composition processes are revealed in graphic scores by looking at the conditions of decision making at the point of preparing a performance. We argue that three key elements are at play in the interpretation of these types of graphic scores: performance practice, mapping and musical form. By reflecting particularly on the work Cipher Series (Rebelo, 2010) we offer insights into the strategies for approaching the performance of graphic scores that go beyond symbolic codification.
Resumo:
Although interactions between seaweeds and sponges have been studied in detail, general information concerning the whole epibiontic algal assemblage associated with a sponge species is virtually non-existent. We present here the first study in which the macroalgal community associated with a sponge, Haliclona indistincta (Bowerbank), was examined in detail. In the period October 2009-September 2010, the seaweed assemblage epibiontic on H. indistincta at a site of the Irish West coast was composed of 66 algal taxa (48 red algae, 7 green algae, 11 brown algae). The red algae Gelidium spinosum and Rhodothamniella floridula were the only epibionts associated with H. indistincta for the whole annual cycle. Most of the algal epibionts were filamentous species, which colonized the surface of the sponge and did not penetrate deeply into it. The algal assemblage was most abundant and species-diverse in the period late winter-spring; multivariate analyses revealed a significant variation of the community on the temporal scale of season and sampling date (weeks to months). The results indicate that the algal communities associated with sponges may be very diverse, showing that this type of assemblage deserves further detailed studies. © 2012 Elsevier B.V.
Resumo:
In his essay, Anti-Object, Kengo Kuma proposes that architecture cannot and should not be understood as object alone but instead always as series of networks and connections, relationships within space and through form. Some of these relationships are tangible, others are invisible. Stan Allen and James Corner have also called for an architecture that is more performative and operative – ‘less concerned with what buildings look like and more concerned with what they do’ – as means of effecting a more intimate and promiscuous relationship between infrastructure, urbanism and buildings. According to Allen this expanding filed offers a reclamation of some of the areas ceded by architecture following disciplinary specialization:
‘Territory, communication and speed are properly infrastructural problems and architecture as a discipline has developed specific technical means to deal with these variables. Mapping, projection, calculation, notation and visualization are among architecture’s traditional tools for operating at the very large scale’.
The motorway may not look like it – partly because we are no longer accustomed to think about it as such – but it is a site for and of architecture, a territory where architecture can be critical and active. If the limits of the discipline have narrowed, then one of the functions of a school of architecture must be an attempt occupy those areas of the built environment where architecture is no longer, or has yet to reach. If this is a project about reclamation of a landscape, it is also a challenge to some of the boundaries that surround architecture and often confine it, as Kuma suggests, to the appreciation of isolated objects.
M:NI 2014-15
We tend to think of the motorway as a thing or an object, something that has a singular function. Historically this is how it has been seen, with engineers designing bridges and embankments and suchlike with zeal … These objects like the M3 Urban Motorway, Belfast’s own Westway, are beautiful of course, but they have caused considerable damage to the city they were inflicted upon.
Actually, it’s the fact that we have seen the motorway as a solid object that has caused this problem. The motorway actually is a fluid and dynamic thing, and it should be seen as such: in fact it’s not an organ at all but actually tissue – something that connects rather than is. Once we start to see the motorway as tissue, it opens up new propositions about what the motorway is, is used for and does. This new dynamic and connective view unlocks the stasis of the motorway as edifice, and allows adaptation to happen: adaptation to old contexts that were ignored by the planners, and adaptation to new contexts that have arisen because of or in spite of our best efforts.
Motorways as tissue are more than just infrastructures: they are landscapes. These landscapes can be seen as surfaces on which flows take place, not only of cars, buses and lorries, but also of the globalized goods carried and the lifestyles and mobilities enabled. Here the infinite speed of urban change of thought transcends the declared speed limit [70 mph] of the motorway, in that a consignment of bananas can cause soil erosion in Equador, or the delivery of a new iphone can unlock connections and ideas the world over.
So what is this new landscape to be like? It may be a parallax-shifting, cognitive looking glass; a drone scape of energy transformation; a collective farm, or maybe part of a hospital. But what’s for sure, is that it is never fixed nor static: it pulses like a heartbeat through that most bland of landscapes, the countryside. It transmits forces like a Caribbean hurricane creating surf on an Atlantic Storm Beach: alien forces that mutate and re-form these places screaming into new, unclear and unintended futures.
And this future is clear: the future is urban. In this small rural country, motorways as tissue have made the whole of it: countryside, mountain, sea and town, into one singular, homogenous and hyper-connected, generic city.
Goodbye, place. Hello, surface!
Resumo:
Climate change is expected to have an impact on plant communities as increased temperatures are expected to drive individual species' distributions polewards. The results of a revisitation study after c. 34years of 89 coastal sites in Scotland, UK, were examined to assess the degree of shifts in species composition that could be accounted for by climate change. There was little evidence for either species retreat northwards or for plots to become more dominated by species with a more southern distribution. At a few sites where significant change occurred, the changes were accounted for by the invasion, or in one instance the removal, of woody species. Also, the vegetation types that showed the most sensitivity to change were all early successional types and changes were primarily the result of succession rather than climate-driven changes. Dune vegetation appears resistant to climate change impacts on the vegetation, either as the vegetation is inherently resistant to change, management prevents increased dominance of more southerly species or because of dispersal limitation to geographically isolated sites.
Resumo:
Harmful algal blooms (HABs) are a natural global phenomena emerging in severity and extent. Incidents have many economic, ecological and human health impacts. Monitoring and providing early warning of toxic HABs are critical for protecting public health. Current monitoring programmes include measuring the number of toxic phytoplankton cells in the water and biotoxin levels in shellfish tissue. As these efforts are demanding and labour intensive, methods which improve the efficiency are essential. This study compares the utilisation of a multitoxin surface plasmon resonance (multitoxin SPR) biosensor with enzyme-linked immunosorbent assay (ELISA) and analytical methods such as high performance liquid chromatography with fluorescence detection (HPLC-FLD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for toxic HAB monitoring efforts in Europe. Seawater samples (n = 256) from European waters, collected 2009-2011, were analysed for biotoxins: saxitoxin and analogues, okadaic acid and dinophysistoxins 1/2 (DTX1/DTX2) and domoic acid responsible for paralytic shellfish poisoning (PSP), diarrheic shellfish poisoning (DSP) and amnesic shellfish poisoning (ASP), respectively. Biotoxins were detected mainly in samples from Spain and Ireland. France and Norway appeared to have the lowest number of toxic samples. Both the multitoxin SPR biosensor and the RNA microarray were more sensitive at detecting toxic HABs than standard light microscopy phytoplankton monitoring. Correlations between each of the detection methods were performed with the overall agreement, based on statistical 2 × 2 comparison tables, between each testing platform ranging between 32% and 74% for all three toxin families illustrating that one individual testing method may not be an ideal solution. An efficient early warning monitoring system for the detection of toxic HABs could therefore be achieved by combining both the multitoxin SPR biosensor and RNA microarray.