Two environmental films were passively collected in different orientations (vertical or horizontal) at the same location over two months. We characterized these films using bright field microscopy, ...total dissolved species analysis, pH analysis, vibrational interfacial spectroscopy, and contact angle goniometry. Results show that horizontal films have significantly higher surface coverage than the vertical samples (+50%). The vertical and horizontal films also show different particle morphologies but the particle size distributions are not statistically different. Vertical surfaces have smaller, less compact particulate suggesting particle adsorption depends on the surface area in contact with the parent substrate. Horizontal surfaces also generate more total dissolved solid material per unit area when washed with water (+61%). The dissolved solids from the vertical substrate are more acidic per unit mass, suggesting increased pH active species like nitrate, sulfate, or organic acids. Vibrational spectroscopy provides evidence of nitrates and sulfates in both films, but spectroscopic profiles show these ions are present in different forms. Contact angle goniometry measurements show horizontal films are more hydrophilic than vertical films, despite being deposited on the same substrate material. We also report significantly different hydrogen bonding environments for condensed water between the two films. Our results suggest that environmental films deposited on vertical vs horizontal surfaces will have significantly different characteristics, informing models for deposition and impacts to human and environmental health.
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•Particles and films on vertical vs. horizontal surfaces have major differences.•Horizontal surfaces show significantly more circular adsorbed particles.•Vertical surfaces show significantly more acidic adsorbed material.•Horizontal surfaces discharge >60% more mass into solution.•Irreversible capillary wetting occurs high coverage surfaces.
Digital technologies play an increasingly prominent role in the reproduction of society and space. Rather than being studied as a separate category of understanding, the ways in which such ...technologies intersect with and inflect upon the real world has provided a recent focus of research. Urban music is inherently spatial, but the ways in which digital technologies have enabled artists to resist injustice, to reproduce space and to reclaim the right to the city has not yet been considered. This article fills the lacuna by exploring how grime artists harness digital technologies to resist marginalization by the mainstream and create new expressions of power. Specifically, it shows how digital enablers have led to the democratization of music, which in turn has empowered grime artists to reclaim the right to represent the spaces of the inner city, and, in doing so, to challenge and subvert more wide-ranging structures of power and inequality. Accordingly, I argue that grime is more than music and is as much a channel of social activism as it is creative expression.
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Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Plant communities show two general responses to gradients of soil resources: a decrease in species richness at high levels of resource availability and an associated shift in species composition from ...small and slowâgrowing species to large and fastâgrowing species. Models attempting to explain these responses have usually focused on a single pattern and provided contradicting predictions concerning the underlying mechanisms. We use an extension of Tilman's resource competition model to investigate the hypothesis that both patterns may originate from the sizeâasymmetric nature of light exploitation by competing plants. The only mechanism producing changes in species richness and species composition in our model is mortality due to competition. Under the framework of the model, asymmetric light exploitation is a necessary and sufficient condition to obtain the empirically observed responses of species richness and species composition to soil resource gradients. This theoretical result is robust to relaxing the simplifying assumptions of the model. Our model shows that the traits enhancing competitive superiority depend on the mode of resource exploitation: under symmetric exploitation, competitive superiority is achieved by tolerance of low resource levels, while under asymmetric exploitation, it is achieved by the ability to grow fast and attain a large size. This result indicates that a longâstanding debate concerning the traits that enhance competitive superiority in plant communities (the âGrimeâTilman debateâ) can be reduced into a single parameter of our model â the degree of asymmetry in resource competition. The model also explains the observed shift from belowâground to aboveâground competition with increasing productivity, the associated increase in the asymmetry of competitive interactions and the increasing likelihood of competitive exclusion under high levels of productivity. None of these patterns could be obtained under symmetric competition in our model. Synthesis. The ability of the model to explain a wide range of observed patterns and the robustness of these predictions to its simplifying assumptions suggest that the size asymmetry of competition for light is a fundamental factor in determining the structure and diversity of plant communities.
Urban grime represents an important environmental surface for heterogeneous reactions in urban environment. Here, we assess the physical and chemical properties of urban grime collected during six ...consecutive months in downtown of Guangzhou, China. There is a significant variation of the uptake coefficients of NO2 on the urban grime as a function of the relative humidity (RH). In absence of water molecules (0% RH), the light-induced uptake coefficients of NO2 on urban grime samples collected during six months are very similar in order of ≈10−6. At 80% RH, depending on the sampling month the light-induced uptake coefficient of NO2 can reach one order of magnitude higher values (1.5 × 10−5, at 80% RH) compared to those uptakes at 0% RH. In presence of 80% RH, there are strong correlations between the measured NO2 uptakes and the concentrations of the water soluble carbon, soluble anions, polycyclic aromatic hydrocarbons and n-alkanes depicted in the urban grime. These correlations, demonstrate that surface adsorbed water on urban grime play an important role for the uptakes of NO2. The heterogeneous conversion of NO2 on two-month old urban grime under sunlight irradiation (68 W m−2, 300 nm < λ < 400 nm) at 60% RH leads to the formation of unprecedented HONO surface flux of 4.7 × 1010 molecules cm−2 s−1 which is higher than all previously observed HONO fluxes, thereby affecting the oxidation capacity of the urban atmosphere. During the heterogeneous chemistry of NO2 with urban grime, the unsaturated and N-containing organic compounds are released in the gas phase which can affect the air quality in the urban environment.
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•Uptakes of NO2 on urban grime increase non-linearly with the RH upon UV irradiation.•Surface adsorbed water plays an important role for uptakes of NO2 on urban grime.•Uptakes of NO2 are well correlated with the chemical composition of urban grime.•Unprecedented HONO surface flux is formed by two-month old grime.•N-containing organic compounds are released in the gas phase of the atmosphere.
1. Three main directions of adaptive specialization are evident in the world flora, reflecting fundamental trade-offs between economics (conservative vs. acquisitive investment of resources) and ...size. The current method of ordinating plants according to these trade-offs, CSR classification, cannot be applied to the woody species that dominate many terrestrial ecosystems. 2. We aimed to produce a novel CSR classification method applicable to vascular plants in general. 3. Principal components analysis (PCA) of variation in a range of plant traits for 678 angiosperm, gymnosperm and pteridophyte species was used to determine the limits to multivariate space occupied by functionally diverse species. From this calibration, correlations between PCA axes and values of leaf dry matter content (LDMC; as an index of conservatism in life history), specific leaf area (SLA; indicative of acquisitive economics) and leaf area (LA; photosynthetic organ size) were used to produce predictor regressions from which target species could be compared against the multivariate space. A spreadsheet was developed that returned ternary coordinates and tertiary CSR strategies for target subjects based on LA, LDMC and SLA values. 4. The method allowed classification of target species within a triangular space corresponding to Grime's theoretical CSR triangle and was sufficiently precise to distinguish strategies between species within genera and within populations of species. It was also largely in agreement with previous methods of CSR classification for herbaceous species. 5. Rapid CSR classification of woody and herbaceous vascular plants is now possible, potentially allowing primary plant functional types and ecosystem processes to be investigated over landscape scales.
1. Whether plant competition grows stronger or weaker across a soil fertility gradient is an area of great debate in plant ecology. We examined the effects of competition and soil fertility and their ...interaction on growth rates of the four dominant tree species in the sub-boreal spruce forest of British Columbia. 2. We tested separate soil nutrient and moisture indices and found much stronger support for models that included the nutrient index as a measure of soil fertility. 3. Competition, soil fertility and their interaction affected radial growth rates for all species. 4. Each species supported a different alternate hypothesis for how competitive interactions changed with soil fertility and whether competition intensity was stronger or weaker overall as soil fertility increased depended on the context, specifically, species, neighbourhood composition and type of competition (shading vs. crowding). 5. The four species varied slightly in their growth response to soil fertility. 6. Individual species had some large variations in the shapes of their negative relationships between shading, crowding and tree growth, with one species experiencing no net negative effects of crowding at low soil fertility. 7. Goodness-of-fit was not substantially increased by models including competition-soil fertility interactions for any species. Tree size, soil fertility, shading and crowding predicted most of the variation in tree growth rates in the sub-boreal spruce forest. 8. Synthesis. The intensity of competition among trees across a fertility gradient was species- and context-specific and more complicated than that predicted by any one of the dominant existing theories in plant ecology.
This paper seeks to expand popular geopolitics in line with the digital worlds in which many of us now live. By interpreting geopolitics as a method of cultural (re)production, it becomes a creative ...tool that can be used to shape and elevate the affective appeal of content. Digital technologies are centrally implicated in the production of such content. By decoupling space and time from their physical anchors in the real world, digital technologies imbue them with a creative latency that can be deployed in both agentic and affective ways. Specifically, decoupling creates spatio‐temporal openings that offer new opportunities for content to be territorialised, and for artists and audiences to be engaged. Digital geopolitics thus considers the ways in which the decoupling of space and time can foreground new types of digitally mediated geopolitical praxis. Through an analysis of music videos exchanged between two grime artists involved in a “clash,” I show how digital technologies enable them to mediate between the different spatio‐temporal logics of the digital and real worlds. Doing so reifies the affective power of space, and the expansive role of popular geopolitics in the digital age.
This paper seeks to expand popular geopolitics in line with the digital worlds in which many of us now live. By decoupling space and time from their physical anchors in the real world, digital technologies imbue them with a creative latency that can be deployed in both agentic and affective ways. Digital geopolitics thus considers the ways in which the decoupling of space and time can foreground new types of digitally mediated geopolitical praxis.
Many experimental studies have quantified how the effects of competition vary with habitat productivity, with the results often interpreted in terms of the ideas of Grime and Tilman. Unfortunately, ...these ideas are not relevant to many experiments, and so we develop an appropriate resource competition model and use this to explore the effects of habitat productivity on the intensity of competition. Several mechanisms influencing the productivity–competition intensity relationship are identified, and these mechanisms explored using two classic data sets. In both cases, there is good agreement between the model predictions and empirical patterns. Quantification of the mechanisms identified by the models will allow the development of a simple predictive theory linking measures of the intensity of competition with ecosystem‐level properties.
Heterogeneous reactions of NO2 on different surfaces play an important role in atmospheric NOx removal and HONO formation, having profound impacts on photochemistry in polluted urban areas. Previous ...studies have suggested that the NO2 uptake on the ground or aerosol surfaces could be a dominant source for elevated HONO during the daytime. However, the uptake behavior of NO2 varies with different surfaces, and different uptake coefficients were used or derived in different studies. To obtain a more holistic picture of heterogeneous NO2 uptake on different surfaces, a series of laboratory experiments using different flow tube reactors was conducted, and the NO2 uptake coefficients (γ) were determined on inorganic particles, sea water and urban grime. The results showed that heterogeneous reactions on those surfaces were generally weak in dark conditions, with the measured γ varied from <10−8 to 3.2 × 10−7 under different humidity. A photo-enhanced uptake of NO2 on urban grime was observed, with the obvious formation of HONO and NO from the heterogeneous reaction. The photo-enhanced γ was measured to be 1.9 × 10−6 at 5% relative humidity (RH) and 5.8 × 10−6 at 70% RH on urban grime, showing a positive RH dependence for both NO2 uptake and HONO formation. The results demonstrate an important role of urban grime in the daytime NO2-to-HONO conversion, and could be helpful to explain the unknown daytime HONO source in the polluted urban area.
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As debates on the rise of violent crime in London unfold, UK drill music is routinely accused of encouraging criminal behaviour among young Black Britons from deprived areas of the capital. Following ...a series of bans against drill music videos and the imposition of Criminal Behaviour Orders and gang injunctions against drill artists, discussions on the defensibility of such measures call for urgent, yet hitherto absent, sociological reflections on a topical issue. This article attempts to fill this gap, by demonstrating how UK drill and earlier Black music genres, like grime, have been criminalised and policed in ways that question the legitimacy of and reveal the discriminatory nature of policing young Black people by the London Metropolitan Police as the coercive arm of the British state. Drawing on the concept of racial neoliberalism, the policing of drill will be approached theoretically as an expression of the discriminatory politics that neoliberal economics facilitates in order to exclude those who the state deems undesirable or undeserving of its protection.
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