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Behan-Pelletier, V. M., und B. Bissett. „ORIBATIDA OF CANADIAN PEATLANDS“. Memoirs of the Entomological Society of Canada 126, S169 (1994): 73–88. http://dx.doi.org/10.4039/entm126169073-1.
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AbstractThis paper reviews and summarizes preliminary data on the taxonomy, distribution, and ecology of oribatid mites of Canadian peatlands, primarily those of eastern Canada. This fauna is a heterogenous assemblage comprising 71 species in 49 genera and 34 families, found in four main types of habitats: aquatic, mesic, xeric, and epigeal. About half of the oribatid fauna of peatlands, and most aquatic species, are restricted in distribution to the Nearctic. Oribatid taxa known or suspected to be parthenogenetic are much better represented in peatlands than in the general Canadian fauna. Data on the feeding habits of odonate larvae in Newfoundland bog pools, based on gut content analysis, show that oribatid mites, in particular species of Limnozetes Hull and Hydrozetes Berlese, are common prey of species of Aeshna Fabricius, Leucorrhina Brittinger, and Libellula L. A synopsis of available data suggests that assemblages of Limnozetes species may be useful in characterizing peatlands.
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Ragan, Ashley N., und Jeffrey R. Wozniak. „Linking Hydrologic Connectivity in Salt Marsh Ponds to Fish Assemblages across a Heterogenous Coastal Habitat“. Journal of Coastal Research 35, Nr. 3 (17.10.2018): 545. http://dx.doi.org/10.2112/jcoastres-d-18-00007.1.
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Robinson, David. „Assemblage Theory and the Capacity to Value: An Archaeological Approach from Cache Cave, California, USA“. Cambridge Archaeological Journal 27, Nr. 1 (11.01.2017): 155–68. http://dx.doi.org/10.1017/s0959774316000639.
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New discoveries from a Californian cave have found a remarkable assemblage of cached perishable and other artefacts. Comprised of baskets, cordage, bone, antler, leather, food residues and other materials, the assemblages are dispersed through four caves in the largest ever cache discovered in the borderland region attributable to the native Californian linguistic group known as the Chumash. This paper develops a methodology based upon DeLanda's philosophy of assemblages and Graeber's anthropological theory of value. Importantly, following Normark, it is argue that assemblage theory needs to be operationalized into a methodological approach in order to apply it archaeologically. This methodology illustrate how a capacity analysis of the Cache Cave assemblage relates to values within the society which cached it by revealing the relational capacities within assemblages and relative capacities between them. Importantly, as a scalable approach, capacity analysis allows the investigation of the heterogeneous dynamics within complex societies.
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Hamilakis, Yannis. „Sensorial Assemblages: Affect, Memory and Temporality in Assemblage Thinking“. Cambridge Archaeological Journal 27, Nr. 1 (11.01.2017): 169–82. http://dx.doi.org/10.1017/s0959774316000676.
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Archaeologists are familiar with the concept of assemblage, but in more recent years they have started problematizing it in interesting and innovative ways, beyond its common connotations of aggregation. Sociologists such as Manuel DeLanda and political philosophers such as Jane Bennett have been key influences in this move. These authors had adapted and modified the assemblage thinking of Deleuze and Guattari. In this article, an assemblage of sorts itself, I propose that we need to return to that original Deleuzian body of thinking and explore its richness further. Assemblages, temporary and deliberate heterogeneous arrangements of material and immaterial elements, are about the relationship of in-betweenness. I further suggest that sensoriality and affectivity, memory and multi-temporality are key features of assemblage thinking, and that assemblages also imply certain political effects. The omission of these features in the archaeological treatments of the concept may lead to mechanistic reincarnations of systems thinking, thus depriving the concept of its potential. Finally, I explore these ideas by considering communal eating and feasting events as powerful sensorial assemblages.
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Alfaro, Julius Raynard D., Donn Lorenz Ivan M. Alcayde, Joel B. Agbulos, Nikki Heherson A. Dagamac und Thomas Edison E. Dela Cruz. „The occurrence of myxomycetes from a lowland montane forest and agricultural plantations of Negros Occidental, Western Visayas, Philippines“. Fine Focus 1, Nr. 1 (01.12.2014): 7–20. http://dx.doi.org/10.33043/ff.1.1.7-20.
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Higher floral and faunal biodiversity is expected in multi-species-covered mountainous forests than in mono-typic agricultural plantations. To verify this supposition for cryptogamic species like the plasmodial slime molds, a rapid field survey was conducted for myxomycetes and substrates in forest floor litter and agricultural plantation were collected in Negros Occidental, Philippines. Morphological characterization identified a total of 28 species belonging to the genera Arcyria, Ceratiomyxa, Collaria, Comatricha, Craterium, Cribraria, Diderma, Didymium, Hemitrichia, Lamproderma, Physarum, Stemonitis, Trichia and Tubifera. The myxomycete species Arcyria cinerea was the only abundant species found both in the agricultural and forested areas. The majority of collected species were rarely occurring. In terms of species composition, more myxomycetes were recorded in the mountainous forest (27) compared to agricultural sites. Furthermore, aerial leaf litter collected in the forests had the highest number of records for fruiting bodies but in terms of species diversity, twigs yielded higher value based on Shannon index. Findings in this study verify that a habitat with more heterogenous plant communities yields higher species of myxomycete assemblages. This research is the first study to report myxomycetes from Negros Occidental.
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Seastedt, Timothy R., und Meagan Oldfather. „Climate Change, Ecosystem Processes and Biological Diversity Responses in High Elevation Communities“. Climate 9, Nr. 5 (19.05.2021): 87. http://dx.doi.org/10.3390/cli9050087.
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The populations, species, and communities in high elevation mountainous regions at or above tree line are being impacted by the changing climate. Mountain systems have been recognized as both resilient and extremely threatened by climate change, requiring a more nuanced understanding of potential trajectories of the biotic communities. For high elevation systems in particular, we need to consider how the interactions among climate drivers and topography currently structure the diversity, species composition, and life-history strategies of these communities. Further, predicting biotic responses to changing climate requires knowledge of intra- and inter-specific climate associations within the context of topographically heterogenous landscapes. Changes in temperature, snow, and rain characteristics at regional scales are amplified or attenuated by slope, aspect, and wind patterns occurring at local scales that are often under a hectare or even a meter in extent. Community assemblages are structured by the soil moisture and growing season duration at these local sites, and directional climate change has the potential to alter these two drivers together, independently, or in opposition to one another due to local, intervening variables. Changes threaten species whose water and growing season duration requirements are locally extirpated or species who may be outcompeted by nearby faster-growing, warmer/drier adapted species. However, barring non-analogue climate conditions, species may also be able to more easily track required resource regimes in topographically heterogenous landscapes. New species arrivals composed of competitors, predators and pathogens can further mediate the direct impacts of the changing climate. Plants are moving uphill, demonstrating primary succession with the emergence of new habitats from snow and rock, but these shifts are constrained over the short term by soil limitations and microbes and ultimately by the lack of colonizable terrestrial surfaces. Meanwhile, both subalpine herbaceous and woody species pose threats to more cold-adapted species. Overall, the multiple interacting direct and indirect effects of the changing climate on high elevation systems may lead to multiple potential trajectories for these systems.
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Crellin, Rachel J. „Changing Assemblages: Vibrant Matter in Burial Assemblages“. Cambridge Archaeological Journal 27, Nr. 1 (11.01.2017): 111–25. http://dx.doi.org/10.1017/s0959774316000664.
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In this paper the notion of assemblage, as derived from the work of Gilles Deleuze, is explored in order to consider change in prehistory. An assemblage-based approach that draws on the concept of ‘vibrant matter’ is implemented as the means of understanding change. In this approach all materials are viewed as vibrant and in flux. These ideas are used to create a heterogeneous view of change where assemblages, or parts of assemblages, may change at varying speeds and rhythms and at many different scales. These ideas are explored through the case study of changing burial practices between 3000 and 1500 cal bc on the Isle of Man. I suggest that this kind of thinking allows us to study change differently, and explore the advantages of this approach for archaeology.
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Battisti, Corrado. „Bird assemblages on a Mediterranean sandy beach: a yearly study“. Rivista Italiana di Ornitologia 84, Nr. 1 (20.03.2015): 23. http://dx.doi.org/10.4081/rio.2014.214.
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Around the 2007 yearly cycle, we carried out a transect in a Mediterranean sandy beach (central Italy), a structurally oversimplified ecosystem, elaborating the data in six bimonthly periods and in three longitudinal habitat types. We observed 25 bird species. Assemblages appear heterogeneous at taxonomic-, phenological- and ecological-level. Also normalizing (Margalef index), in winter the beach hosted the richest assemblage, in summer-autumn the lowest. The inner dunal area appears the richest habitat type. Here, the presence of vegetation presumably permits the occurrence of a large availability of different trophic resources for different species. Beaches represent patchy ecosystems with a different availability of resources in space and time that host heterogeneous bird assemblages, different in their ecology and phenology around a yearly cycle.
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Zedeño, María Nieves. „Animating by Association: Index Objects and Relational Taxonomies“. Cambridge Archaeological Journal 19, Nr. 3 (Oktober 2009): 407–17. http://dx.doi.org/10.1017/s0959774309000596.
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Despite great variability in archaeological and ethnographic material culture across North America, a handful of objects are ubiquitous in assemblages of different ages and geographies. These index objects are clues to ontological principles, such as animacy, that guide the interactions between Native Americans and the material world. The impact of relational ontologies on the formation of heterogeneous archaeological assemblages may be evaluated through analyses of index objects and contextual associations. To this effect, this article presents the outline of an assemblage-based relational taxonomy, where spatial, temporal, and formal dimensions are combined with object biographies, interactive roles, and social relations.
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Rødje, Kjetil. „Intra-Diegetic Cameras as Cinematic Actor Assemblages in Found Footage Horror Cinema“. Film-Philosophy 21, Nr. 2 (Juni 2017): 206–22. http://dx.doi.org/10.3366/film.2017.0044.
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This article proposes a reconceptualization of the term “actor” within motion pictures and presents the argument that “acting” is a matter of distributed agency performed by heterogeneous assemblages. What constitutes an actor is what I will label as a “cinematic actor assemblage,” a term that comprises what is commonly known as human actors as well as material entities that play an active part in motion picture images. The use of intra-diegetic cameras in contemporary found footage horror films constitutes a particular case of such cinematic actor assemblages. Through a dynamic relational performance, cameras here take on roles as active agents with the potential to affect other elements within the images as well as the films’ audiences. In found footage horror the assemblage mode of operation creates suspense, since the vulnerability of the camera threatens the viewer's access to the depicted events. While human characters and individual entities making up the camera assemblage are disposable, the recording is not. Found footage horror crucially hinges upon the survival of the footage. I will further suggest that these films allow filmmakers to experiment with the acting capabilities of intra-diegetic cameras.
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Stortini, CH, B. Petrie, KT Frank und WC Leggett. „Marine macroinvertebrate species-area relationships, assemblage structure and their environmental drivers on submarine banks“. Marine Ecology Progress Series 641 (07.05.2020): 25–47. http://dx.doi.org/10.3354/meps13306.
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Modern extensions of the theory of island biogeography (TIB) posit that the slope of the species-area relationship (SAR) reflects the insularity of ecological communities and is strongly influenced by species’ motility. We explore the relative insularity of crustacean, echinoderm and mollusk/Cirripedia assemblages in terms of both alpha diversity (species richness) and assemblage structure (relative biomass of species). These taxa/groups differ in adult motility and larval dispersal capacity. The habitats of interest were 10 offshore banks on the Scotian Shelf, northwest Atlantic Ocean, a region dominated by the NE- to SW-flowing Nova Scotia Current (NSC). Banks in the NE tended to be larger, more heterogeneous, cooler, less saline, more retentive and more productive (higher chlorophyll a) than those in the SW. Only mollusks/Cirripedia, the least motile and dispersive group, had a significant SAR slope, supporting TIB. For crustaceans and echinoderms, temperature/salinity properties and habitat heterogeneity, respectively, were important predictors of alpha diversity. Inter-bank variation in crustacean assemblage structure was accounted for largely by bank location relative to the NSC; the leading variables accounting for echinoderm and mollusk/Cirripedia assemblage structure were retention time and mean annual chlorophyll concentration, respectively. Along the NE to SW axis of the NSC, there was a substantial loss of species (7 crustacean, 9 echinoderm and 13 mollusk/Cirripedia species) and decreases in the biomass of common cold-water species. A complex interplay of species motility/dispersal capacity, local oceanography and habitat properties determine the extent to which (1) TIB applies to submarine macroinvertebrate assemblages and (2) upstream and downstream assemblages are interconnected.
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Liu, Bo, Yifei Gao, Kouqi Liu, Jinzhong Liu, Mehdi Ostadhassan, Tong Wu und Xianli Li. „Pore structure and adsorption hysteresis of the middle Jurassic Xishanyao shale formation in the Southern Junggar Basin, northwest China“. Energy Exploration & Exploitation 39, Nr. 3 (07.01.2021): 761–78. http://dx.doi.org/10.1177/0144598720985136.
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In order to understand the pore structures of the Middle Jurassic Xishanyao Formation in the Junggar Basin, 11 shale samples from a single well were picked and were subjected to several analyses including mineralogy, (programmed) Rock-Eval pyrolysis for geochemical and N2 adsorption for pore structure analysis. The results showed that the mean value of total organic carbon (TOC) content of these samples is around 1.54% while Tmax varies between 429 to 443°C, indicating they are in the oil window. Mineral assemblages of the samples is mainly quartz and clay (illite, chlorite and kaolinite). Moreover, negative correlations between the K-feldspar/plagioclase and micro-mesopore volume was found, depicting that few of such pore sizes exist in these two abundant minerals. In contrast, micro, meso and macro pores all were detected in clay minerals. Particularly, the pores with radii of around 5.35 nm were abundant in clay minerals and there was not a robust relationship between the organic matter, surface area and pore volume. Finally, fractal analysis was performed to better delineate heterogenous characteristics of pore structures which showed that D2 (representing the larger pores) is greater than D1 (smaller pores). In addition, the differences between the fractal dimensions of the adsorption and desorption (D2d–D2a) branches to better interpret the hysteresis, was defined. The positive correlation between the (D2d–D2a) and the meso-macro pore volume, pointed out that the meso-macro condensation is the main reason for hysteresis that was observed in N2 adsorption experiments in the Xishanyao Shale samples.
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Lecová, L., F. Weisz, P. Tůmová, V. Tolarová und E. Nohýnková. „The first multilocus genotype analysis of Giardia intestinalis in humans in the Czech Republic“. Parasitology 145, Nr. 12 (20.03.2018): 1577–87. http://dx.doi.org/10.1017/s0031182018000409.
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AbstractTo date, genotyping data on giardiasis have not been available in the Czech Republic. In this study, we characterized 47 human isolates of Giardia intestinalis from symptomatic as well as asymptomatic giardiasis cases. Genomic DNA from trophozoites was tested by PCR-sequence analysis at three loci (β-giardin, glutamate dehydrogenase and triose phosphate isomerase). Sequence analysis showed assemblages A and B in 41 (87.2%) and six (12.8%) isolates, respectively. Two of the 41 assemblage A samples were genotyped as sub-assemblage AI, and 39 were genotyped as sub-assemblage AII. Four previously identified multilocus genotypes (MLGs: AI-1, AII-1, AII-4 and AII-9) and six likely novel variations of MLGs were found. In agreement with previous studies, sequences from assemblage B isolates were characterized by a large genetic variability and by the presence of heterogeneous positions, which prevent the definition of MLGs. This study also investigated whether there was a relationship between the assemblage and clinical data (including drug resistance). However, due to the large number of genotypes and the relatively small number of samples, no significant associations with the clinical data were found.
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Ollivier, Q. R., N. A. Bramwell, E. Hammill, C. Foster-Thorpe und D. J. Booth. „Are the effects of adjacent habitat type on seagrass gastropod communities being masked by previous focus on habitat dyads?“ Australian Journal of Zoology 63, Nr. 5 (2015): 357. http://dx.doi.org/10.1071/zo15057.
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Variation in abundance and diversity of organisms along habitat edges has long been a key research focus in both terrestrial and marine ecosystems. Previous investigations into edge effects in seagrass ecosystems have predominantly focussed on the seagrass–sandy substrate boundary. However, little is known about what role other habitats (e.g. rocky algal reefs) may play in faunal assemblage patterns. This study investigated the strength to which habitat type influenced gastropod assemblages within seagrass (Posidonia australis) beds, bordered by both sandy substrate and rocky algal reef. We found that benthic invertebrate community composition significantly changed with distance from rocky algal reef, but not with distance from sandy substrate. Proximity to rocky reef had a stronger effect on community composition than other local drivers examined (seagrass biomass and sand particle size). We hypothesise that gastropod affinity for rocky algal reef may be a result of both species-specific habitat preference, and lower predation pressure along adjacent rocky algal reef habitats. This study provides evidence that heterogeneous habitats within close proximity to seagrass beds may exert previously overlooked effects on the distribution of gastropod assemblages, highlighting the need for the inclusion of adjacent habitat type in experimental design for gastropod assemblage distribution studies.
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Willink, Philip Wesley, Eustace Alexander und Christopher Campbell Jones. „Using fish assemblages in different habitats to develop a management plan for the Upper Essequibo Conservation Concession, Guyana“. Biota Neotropica 13, Nr. 4 (Dezember 2013): 260–68. http://dx.doi.org/10.1590/s1676-06032013000400023.
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The Upper Essequibo Conservation Concession is a reserve in central-eastern Guyana managed by Conservation International. The site is uninhabited by people and poorly studied. The first scientific fish survey was in 2007 in conjunction with the filming of the BBC nature documentary Lost Land of the Jaguar. Aquatic habitats were primarily flowing water, ranging from the main channel of the Essequibo River to small forest creeks. Ponds and seasonally flooded forests were uncommon. Large predatory fishes were abundant in the Essequibo River. Fishes tolerant of low oxygen levels were common in flooded forests and small forest creeks. There was zero similarity between the fish assemblages of the Essequibo River and flooded forests / small forest creeks. The rest of the habitats and fish assemblages formed a continuum between these extremes. Imminent threats to the Upper Essequibo Conservation Concession include logging, mining, and over-fishing. Because of the heterogeneous distribution of fish assemblages, and because each threat will differentially affect different habitats, a two-pronged approach focusing on the ends of the habitat / fish assemblage continuum should be implemented in order to conserve the entire fish biodiversity of the Upper Essequibo Conservation Concession.
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Stauff, Markus. „The Second Screen: Convergence as Crisis“. Zeitschrift für Medien- und Kulturforschung 6, Nr. 2 (2015): 123–44. http://dx.doi.org/10.28937/1000106448.
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Dieser Artikel nimmt den >zweiten Bildschirm< – TV-bezogene Nutzung von Smartphones und Tablets – zum Ausgangspunkt, um die immer heterogeneren Verbindungen zwischen mehreren Geräten, Texten und Plattformen zu diskutieren, von denen die zeitgenössische Kultur geformt wird. Sie bilden instabile Assemblagen, die die spezifischen affordances (Aufforderungscharaktere) ihrer Elemente gleichzeitig hervorheben und untergraben. Indem der Fokus zunächst auf technische und industrielle, sodann auf praktische und heimische Verfahren der Herstellung von Verbindungen gelegt wird, wird die aktuelle Medienlandschaft als »Konvergenz in der Krise« beschrieben: Während Medien in der Tat immer mehr miteinander verbunden werden, bleiben die Verbindungen selbst und die Form der Montage in ihrer Gänze flüchtig, instabil und vage. Konvergenz entsteht und besteht als In-der-Krise-sein. </br></br>This article takes the second screen – television-related use of smart phones and tablet computers – as a starting point to discuss how current culture is shaped by the ever more heterogeneous connections between multiple devices, texts and platforms. They form unstable assemblages that simultaneously highlight and undermine the specific affordances of their elements. Focusing first on technical and industrial and then on practical and domestic procedures of creating connections, the current media landscape will be described as >convergence as crisis<: While media indeed become increasingly more interconnected, the connections themselves and the shape of the assemblage in its entirety are ephemeral, unstable and vague. Convergence mainly exists and is generated through being in crisis.
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Arp Fallov, Mia, und Rasmus Hoffmann Birk. „Translating Inclusion“. Space and Culture 23, Nr. 4 (23.09.2018): 536–47. http://dx.doi.org/10.1177/1206331218800237.
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The purpose of this article is to explore how practices of translation shape particular paths of inclusion for people living in marginalized residential areas in Denmark. Inclusion, we argue, is not an end-state but rather something that must be constantly performed. Active citizenship, today, is not merely a question of participation but also learning to become active in all spheres of life. The article draws on empirical examples from a multisite fieldwork in six different sites of local community work in Denmark, to demonstrate how different dimensions of translation are involved in shaping active citizenship. We propose the following different dimensions of translation: translating authority, translating language, and translating social problems. The article takes its theoretical point of departure from assemblage urbanism, arguing that cities are heterogeneous assemblages of sociomaterial interactions. Through the practices of translation, local community work both transforms the possibilities for residents and disrupts the compositions of urban assemblages. Through this, we argue, local community work creates new opportunities for residents.
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Mayes, K. R., M. Luján, G. D. Riley, J. Chin, P. V. Coveney und J. R. Gurd. „Towards performance control on the Grid“. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 363, Nr. 1833 (18.07.2005): 1793–805. http://dx.doi.org/10.1098/rsta.2005.1607.
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Advances in computational Grid technologies are enabling the development of simulations of complex biological and physical systems. Such simulations can be assembled from separate components—separately deployable computation units of well-defined functionality. Such an assemblage can represent an application composed of interacting simulations or might comprise multiple instances of a simulation executing together, each running with different simulation parameters. However, such assemblages need the ability to cope with heterogeneous and dynamically changing execution environments, particularly where such changes can affect performance. This paper describes the design and implementation of a prototype performance control system (PerCo), which is capable of monitoring the progress of simulations and redeploying them so as to optimize performance. The ability to control performance by redeployment is demonstrated using an assemblage of lattice Boltzmann simulations running with and without control policies. The cost of using PerCo is evaluated and it is shown that PerCo is able to reduce overall execution time.
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Herman, Agatha. „Assembling Fairtrade: Practices of progress and conventionalization in the Chilean wine industry“. Environment and Planning A: Economy and Space 51, Nr. 1 (08.10.2018): 51–68. http://dx.doi.org/10.1177/0308518x18805747.
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The global Fairtrade system is multiple, heterogeneous and dynamic. The processes that underlie its contextual formations are key, and this paper analyses these through bringing together assemblage thinking and social practices to discuss Fairtrade in the Chilean wine industry. Local-level contestations and appropriation highlight the different forms Fairtrade takes at the micro-scale, which maintain a contextual heterogeneity without challenging the overall coherence of the Fairtrade economy. Power relations are uneven and the important role of local and international ‘assemblage converters’ in catalysing and curtailing possibilities for Fairtrade practices is highlighted. These operate within and across scales, interacting, and varyingly integrated, with other similarly multi-scalar assemblages to support or disrupt particular stabilized compositions. Fairtrade emerges as simultaneously globally coherent and locally fragmented, a system in constant motion between alternative and conventional relations and practices. To challenge creeping conventionalization, the paper concludes that maintaining space for unpredictability and creativity is critical to Fairtrade’s future through making space for enhancing opportunities and for alternatives to take flight.
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Annabi-Trabelsi, Neila, Gamal El-Shabrawy, Mohamed E. Goher, Madhavapeddi N. V. Subrahmanyam, Yousef Al-Enezi, Mohammad Ali, Habib Ayadi und Genuario Belmonte. „Key Drivers for Copepod Assemblages in a Eutrophic Coastal Brackish Lake“. Water 11, Nr. 2 (20.02.2019): 363. http://dx.doi.org/10.3390/w11020363.
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The copepod assemblages and abiotic parameters were investigated at 11 stations in a large coastal lake (Lake Manzalah, Nile Delta) from 2009–2010 in order to verify any impacts of eutrophication and salinity on the copepod species composition. The environmental conditions and the copepod assemblages appeared to have changed in comparison with previous studies, possibly because of increasing eutrophication and invasions of non-indigenous species (NIS). The aim of the present study was the identification of species which can be used as ecological indicators of high trophic status. Among the nine copepod species of Lake Manzalah, Acartia tonsa, Mesocyclops ogunnus, and Apocyclops panamensis were reported for the first time. Acartia tonsa, a well-known NIS for the Mediterranean, numerically dominated the copepod assemblages in some portions of the lake. The distribution of Acanthocyclops trajani and Thermocyclops consimilis was insensible to eutrophication because they can stand high levels of nutrients and hypoxia. Compared with previous reports, the copepod assemblage of Lake Manzalah was richer in species. The invasions of NIS, in addition to the heterogeneous progress of eutrophication in the lake, created an environmental mosaic with many species in total, but with single areas suitable for only a small number of them.
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Englmaier, Gernot K., Daniel S. Hayes, Paul Meulenbroek, Yonas Terefe, Aschalew Lakew, Genanaw Tesfaye, Herwig Waidbacher et al. „Longitudinal river zonation in the tropics: examples of fish and caddisflies from the endorheic Awash River, Ethiopia“. Hydrobiologia 847, Nr. 19 (16.09.2020): 4063–90. http://dx.doi.org/10.1007/s10750-020-04400-0.
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Abstract Specific concepts of fluvial ecology are well studied in riverine ecosystems of the temperate zone but poorly investigated in the Afrotropical region. Hence, we examined the longitudinal zonation of fish and adult caddisfly (Trichoptera) assemblages in the endorheic Awash River (1,250 km in length), Ethiopia. We expected that species assemblages are structured along environmental gradients, reflecting the pattern of large-scale freshwater ecoregions. We applied multivariate statistical methods to test for differences in spatial species assemblage structure and identified characteristic taxa of the observed biocoenoses by indicator species analyses. Fish and caddisfly assemblages were clustered into highland and lowland communities, following the freshwater ecoregions, but separated by an ecotone with highest biodiversity. Moreover, the caddisfly results suggest separating the heterogeneous highlands into a forested and a deforested zone. Surprisingly, the Awash drainage is rather species-poor: only 11 fish (1 endemic, 2 introduced) and 28 caddisfly species (8 new records for Ethiopia) were recorded from the mainstem and its major tributaries. Nevertheless, specialized species characterize the highland forests, whereas the lowlands primarily host geographically widely distributed species. This study showed that a combined approach of fish and caddisflies is a suitable method for assessing regional characteristics of fluvial ecosystems in the tropics.
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Jacobs, Jennifer M., Rudolf von May, David H. Kavanaugh und Edward F. Connor. „Beetles in bamboo forests: community structure in a heterogeneous landscape of southwestern Amazonia“. PeerJ 6 (03.07.2018): e5153. http://dx.doi.org/10.7717/peerj.5153.
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Amazonian bamboo forests dominated by large woody bamboo plants in the genusGuaduacover approximately 180,000 km2and represent a key resource for many organisms. In southwestern Amazonia, native bamboo forests differ in structure, biodiversity, and growth dynamics from other forest types in the region. However, with the exception of a few species in which habitat specialization or a strong habitat association has been demonstrated, little is known about how bamboo forests influence animal community structure. In an effort to understand more about the animal assemblages associated with Amazonian bamboo forests, we characterized the structure of ground-dwelling beetle assemblages living in bamboo forests and adjacent terra firme forests in a lowland rainforest site in Peru. We conducted intensive pitfall trap surveys in 13 bamboo habitat patches and 13 adjacent terra firme habitat patches to determine if there were differences in the abundance and richness of beetle species in these two habitat types. Additionally, given that southwestern Amazonia experiences distinct dry and wet seasons, we conducted our study during the dry and wet season of one year to account for differences in seasonality. We found a distinct beetle assemblage associated with each forest type, and identified a set of dominant species that significantly contributed to the distinctness in beetle community structure between bamboo and terra firme forest. The terra firme forest had a greater number of rare species than the bamboo forest. Several beetle species exhibited a strong association with the bamboo forest, including a large species of Scarabaeidae that appears to be specializing on bamboo. We also found marked differences in beetle assemblages between dry and wet seasons. Our results support the prediction that beetle community structure in bamboo forest differs from that of terra firme in terms of species richness, abundance, and composition. Bamboo-associated animal communities require more exploration and study, and must be included in regional conservation plans seeking to protect entire animal communities in southwestern Amazonia.
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Torres, Marcos Timóteo, Jorge Luiz Pereira Souza und Fabricio Beggiato Baccaro. „Distribution of epigeic and hypogeic ants (Hymenoptera: Formicidae) in ombrophilous forests in the Brazilian Amazon“. Sociobiology 67, Nr. 2 (30.06.2020): 186. http://dx.doi.org/10.13102/sociobiology.v67i2.4851.
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In the Amazon basin, ants are often associated with environmental or edaphic factors. However, these associations may vary between the epigeic and hypogeic strata. Here, we investigated differences in richness and composition of epigeic and hypogeic ant assemblages along an environmental gradient in the Brazilian Amazon. The four studied sites cover different topographic and soil characteristics. We sampled 25 plots of 250 m2 using 10 samples of epigeic pitfalls and 10 samples of hypogeic pitfalls installed at two depths (10 and 30 cm). The pitfalls remained in the fi eld for 48 hours. In the same plots, soil clay content and terrain altitude were also measured. We collected 219 species or morphospecies, of which 14 were exclusively hypogeics. We found higher local richness in the epigeic compared to hypogeic assemblages. We also found an interaction between clay content and strata for ant species composition. Overall, the species turnover was related to clay content, but the eff ect depended on the strata, with hypogeic fauna being more heterogeneous, compared with epigeic fauna. Despite the relationship between clay content and ant´s assemblage’s composition, we did not find strong environment predictors for both strata, which suggests that other factors may structure ant assemblages in these sites. This reinforces the need for studies to defi ne which environmental gradiente determines the distribution of Amazonian epigeic and hypogeic ants.
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LOUGHNEY, KATHARINE M., und CATHERINE BADGLEY. „THE INFLUENCE OF DEPOSITIONAL ENVIRONMENT AND BASIN HISTORY ON THE TAPHONOMY OF MAMMALIAN ASSEMBLAGES FROM THE BARSTOW FORMATION (MIDDLE MIOCENE), CALIFORNIA“. PALAIOS 35, Nr. 4 (16.04.2020): 175–90. http://dx.doi.org/10.2110/palo.2019.067.
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ABSTRACT The Barstow Formation in the Mojave region of California was deposited in an extensional-basin setting of the Basin and Range province and preserves diverse middle Miocene mammalian assemblages. Six facies associations represent the dominant depositional environments in the basin, which changed through time from alluvial-fan and playa-dominated settings to floodplains and spring-fed wetlands. The majority of fossil localities and specimens occur in later-forming facies associations. We analyzed the taphonomic characteristics of fossil assemblages to test whether basin-scale facies associations or locality-scale facies exert more control on the preservational features of mammalian assemblages through the formation. We documented the facies settings of 47 vertebrate localities in the field in order to interpret depositional setting and the mode of accumulation for fossil assemblages. We evaluated skeletal material in museum collections for taphonomic indicators, including weathering stage, original bone-damage patterns, hydraulic equivalence, and skeletal-element composition. We evaluated four alternative modes of accumulation, including attritional accumulation on the land surface, accumulation by fluvial processes, carnivore or scavenger accumulations, and mass-death events. The majority of localities represent attritional accumulations at sites of long-term mortality in channel-margin, abandoned-channel, poorly drained floodplain, and ephemeral-wetland settings. Skeletal-element composition and taphonomic characteristics varied among facies, indicating an important role for depositional setting and landscape position on fossil-assemblage preservation. We find that locality-scale facies have a greater influence on the taphonomic characteristics of fossil assemblages; the taphonomy of each facies association is influenced by the facies that compose it. The facies composition and distribution within facies associations change through the formation, with a greater variety of depositional settings forming later in the history of the basin. Heterogeneous landscapes present more settings for fossil accumulation, contributing to the increase in fossil occurrence through the depositional history of the formation.
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Briassoulis, Helen. „Becoming E-Petition: An Assemblage-Based Framework for Analysis and Research“. SAGE Open 11, Nr. 1 (Januar 2021): 215824402110013. http://dx.doi.org/10.1177/21582440211001354.
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Ε-petitions, the digital version of printed petitions, are increasingly being used as complimentary means of nonconfrontational, online citizen mobilization/protest. They attract considerable research interest because they provide (big) data to study e-petitioning and the political and other aspects of socio-spatial issues. E-petition studies lack discussion of ontology, of “what is an e-petition,” implicitly treating e-petitions as “systems-as-a-whole” or, seldom, as relational formations. Acknowledging the foundational role of ontology, Assemblage Thinking (AT) is argued to beget a more judicious approach when e-petitions are employed as research instruments to study the “who-what-when-where-and-how” of a socio-spatial issue and, concurrently, their situated contribution to issue-related decision-making. After presenting the reductionist/essentialist and the nonreductionist/relational approaches to the study of e-petitions and introducing ΑΤ, an assemblage-based framework is proposed that conceptualizes e-petitions as multiplicities comprising assemblages, dynamic compositions emerging from processes of heterogeneous components coming together to serve a purpose. A concomitant methodology is outlined and an illustrative example is offered. The advantages of assemblage-based over reductionist/essentialist approaches for the situated co-analysis of socio-spatial issues and e-petitions are discussed, indicating how they address prominent concerns of the literature, and future research directions are suggested.
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Fava, Natália M. N., Rodrigo M. Soares, Luana A. M. Scalia, Evanguedes Kalapothakis, Isabella F. Pena, Carlos U. Vieira, Elaine S. M. Faria, Maria J. Cunha, Talles R. Couto und Márcia Cristina Cury. „Performance of Glutamate Dehydrogenase and Triose Phosphate Isomerase Genes in the Analysis of Genotypic Variability of Isolates ofGiardia duodenalisfrom Livestocks“. BioMed Research International 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/875048.
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Giardia duodenalisis a small intestinal protozoan parasite of several terrestrial vertebrates. This work aims to assess the genotypic variability ofGiardia duodenalisisolates from cattle, sheep and pigs in the Southeast of Brazil, by comparing the standard characterization between glutamate dehydrogenase (gdh) and triose phosphate isomerase (tpi) primers. Fecal samples from the three groups of animals were analyzed using the zinc sulphate centrifugal flotation technique. Out of 59 positive samples, 30 were from cattle, 26 from sheep and 3 from pigs. Cyst pellets were stored and submitted to PCR and nested-PCR reactions withgdhandtpiprimers. Fragment amplification ofgdhandtpigenes was observed in 25 (42.4%) and 36 (61.0%) samples, respectively. Regarding the sequencing, 24 sequences were obtained withgdhand 20 withtpi. For both genes, there was a prevalence of E specific species assemblage, although some isolates have been identified as A and B, by thetpisequencing. This has also shown a larger number of heterogeneous sequences, which have been attribute to mixed infections between assemblages B and E. The largest variability of inter-assemblage associated to the frequency of heterogeneity provided bytpisequencing reinforces the polymorphic nature of this gene and makes it an excellent target for studies on molecular epidemiology.
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Liu, Jun, Zheng-Shuang Hua, Lin-Xing Chen, Jia-Liang Kuang, Sheng-Jin Li, Wen-Sheng Shu und Li-Nan Huang. „Correlating Microbial Diversity Patterns with Geochemistry in an Extreme and Heterogeneous Environment of Mine Tailings“. Applied and Environmental Microbiology 80, Nr. 12 (11.04.2014): 3677–86. http://dx.doi.org/10.1128/aem.00294-14.
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ABSTRACTRecent molecular surveys have advanced our understanding of the forces shaping the large-scale ecological distribution of microbes in Earth's extreme habitats, such as hot springs and acid mine drainage. However, few investigations have attempted dense spatial analyses of specific sites to resolve the local diversity of these extraordinary organisms and how communities are shaped by the harsh environmental conditions found there. We have applied a 16S rRNA gene-targeted 454 pyrosequencing approach to explore the phylogenetic differentiation among 90 microbial communities from a massive copper tailing impoundment generating acidic drainage and coupled these variations in community composition with geochemical parameters to reveal ecological interactions in this extreme environment. Our data showed that the overall microbial diversity estimates and relative abundances of most of the dominant lineages were significantly correlated with pH, with the simplest assemblages occurring under extremely acidic conditions and more diverse assemblages associated with neutral pHs. The consistent shifts in community composition along the pH gradient indicated that different taxa were involved in the different acidification stages of the mine tailings. Moreover, the effect of pH in shaping phylogenetic structure within specific lineages was also clearly evident, although the phylogenetic differentiations within theAlphaproteobacteria,Deltaproteobacteria, andFirmicuteswere attributed to variations in ferric and ferrous iron concentrations. Application of the microbial assemblage prediction model further supported pH as the major factor driving community structure and demonstrated that several of the major lineages are readily predictable. Together, these results suggest that pH is primarily responsible for structuring whole communities in the extreme and heterogeneous mine tailings, although the diverse microbial taxa may respond differently to various environmental conditions.
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MARAGNO, FRANCIELE P., TIAGO G. SANTOS und SONIA Z. CECHIN. „The role of phytophysiognomies and seasonality on the structure of ground-dwelling anuran (Amphibia) in the Pampa biome, southern Brazil“. Anais da Academia Brasileira de Ciências 85, Nr. 3 (September 2013): 1105–16. http://dx.doi.org/10.1590/s0001-37652013005000042.
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ABSTRACT Considering that habitat use by amphibians is related both with climate and environmental features, we tested the hypothesis that anuran assemblages found in different phytophysiognomies and in different seasons vary in structure. Additionally, we searched for species which can be indicators of habitat and seasons. The study was conducted in the Pampa biome, southern Brazil. Sampling was done through pitfall traps placed in three phytophysiognomies: grassland, ecotone grassland/forest; and forest. The seasonality factor was created by grouping months in warn and cold seasons. Sixteen species were found and the assemblages were influenced both by phytophysiognomies and climatic seasonality. In a paired comparison, the three phytophysiognomies differed in structure of assemblage from each other. Physalaemus henselii, P. riograndensis, Pseudopaludicola falcipes and Pseudis minuta were indicators of ecotone. Leptodactylus gracilis and Physalaemus biligonigerus were indicators of grassland. None species was indicator of forest. Most of the species were indicators of warm season: Elachistocleis bicolor, Leptodactylus fuscus, L. gracilis, L. latinasus, L. latrans, L. mystacinus, Physalaemus biligonigerus, P. cuvieri and Pseudis minuta. None species was indicator of cold season. We found that even for species of open areas, as Pampa, heterogeneous phytophysiognomies are important for maintaining abundance and constancy of populations of anuran.
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Gotelli, Nicholas J., Robert M. Dorazio, Aaron M. Ellison und Gary D. Grossman. „Detecting temporal trends in species assemblages with bootstrapping procedures and hierarchical models“. Philosophical Transactions of the Royal Society B: Biological Sciences 365, Nr. 1558 (27.11.2010): 3621–31. http://dx.doi.org/10.1098/rstb.2010.0262.
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Quantifying patterns of temporal trends in species assemblages is an important analytical challenge in community ecology. We describe methods of analysis that can be applied to a matrix of counts of individuals that is organized by species (rows) and time-ordered sampling periods (columns). We first developed a bootstrapping procedure to test the null hypothesis of random sampling from a stationary species abundance distribution with temporally varying sampling probabilities. This procedure can be modified to account for undetected species. We next developed a hierarchical model to estimate species-specific trends in abundance while accounting for species-specific probabilities of detection. We analysed two long-term datasets on stream fishes and grassland insects to demonstrate these methods. For both assemblages, the bootstrap test indicated that temporal trends in abundance were more heterogeneous than expected under the null model. We used the hierarchical model to estimate trends in abundance and identified sets of species in each assemblage that were steadily increasing, decreasing or remaining constant in abundance over more than a decade of standardized annual surveys. Our methods of analysis are broadly applicable to other ecological datasets, and they represent an advance over most existing procedures, which do not incorporate effects of incomplete sampling and imperfect detection.
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Palminteri, Suzanne, George V. N. Powell und Carlos A. Peres. „Regional-scale heterogeneity in primate community structure at multiple undisturbed forest sites across south-eastern Peru“. Journal of Tropical Ecology 27, Nr. 2 (01.02.2011): 181–94. http://dx.doi.org/10.1017/s0266467410000684.
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Abstract:The forests of western Amazonia support high site-level biological diversity, yet regional community heterogeneity is poorly understood. Using data from line transect surveys at 37 forest sites in south-eastern Peru, we assessed whether local primate assemblages are heterogeneous at the scale of a major watershed. We examined patterns of richness, abundance and community structure as a function of forest type, hunting pressure, land-management regime and geographic location. The primate assemblage composition and structure varied spatially across this relatively small region of Amazonia (≈ 85 000 km2), resulting from large-scale species patchiness rather than species turnover. Primate species richness varied among sites by a factor of two, community similarity by a factor of four and aggregate biomass by a factor of 45. Several environmental variables exhibited influence on community heterogeneity, though none as much as geographic location. Unflooded forest sites had higher species richness than floodplain forests, although neither numerical primate abundance nor aggregate biomass varied with forest type. Non-hunted sites safeguarded higher abundance and biomass, particularly of large-bodied species, than hunted sites. Spatial differences among species assemblages of a relatively generalist taxon like primates in this largely undisturbed forest region imply that community heterogeneity may be even greater in more species-rich taxa, as well as in regions of greater forest habitat diversity.
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BRAMBURGER, ANDREW J., JAY W. MUNYON und EVELYN E. GAISER. „Water Quality and Wet Season Diatom Assemblage Characteristics from the Tamiami Trail Pilot Swales Sites (Everglades National Park, Florida, USA)“. Phytotaxa 127, Nr. 1 (29.08.2013): 163. http://dx.doi.org/10.11646/phytotaxa.127.1.16.
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A pivotal component of hydrological restoration of the Florida Everglades is the improvement of water conveyance to Everglades National Park by the degradation of the current network of canals, roadways and levees. The Tamiami Trail (L29) road/canal complex represents a major barrier to natural water flows into the park and a variety of modification options for flow improvement are currently being explored, including the installation of spreader swales immediately downstream of culverts conveying water under Tamiami Trail from the L29 canal into Everglades National Park. In this study, we evaluated water column chemistry and wet-season diatom community structure to provide baseline information for use in future monitoring activities related to the proposed Tamiami Trail modifications. Water chemistry showed pronounced fluctuations in response to precipitation and anthropogenically mediated hydrological events. Differences in water quality variables among sites were dampened during periods of inundation, and became more pronounced during periods of low canal stage, suggesting the importance of small-scale mechanisms related to isolation of habitat patches. Diatom assemblages were unexpectedly speciose (127 taxa in 40 samples) compared to typical Everglades assemblages, and spatially heterogeneous in sites associated with concentric areas of dense vegetation immediately downstream of culverts. We also observed significant compositional dissimilarities among transects, indicating that culvert pool and north transect assemblages were substantially influenced by propagule input from the canal and areas to the north, while south transect sites were compositionally similar to typical sawgrass prairie diatom communities. Central transect sites were compositionally intermediate to their north and south counterparts. We propose that the position and spatial extent of this “transitional assemblage” is a sensitive indicator of subtle environmental change related to Tamiami Trail modifications.
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Blok, Anders. „Urban Green Assemblages“. Science & Technology Studies 26, Nr. 1 (01.01.2013): 5–24. http://dx.doi.org/10.23987/sts.55306.
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In this article, I sketch an STS-theoretical approach to world-wide growing concerns with urban climate risks and sustainable urbanism more generally in terms of what I call ‘urban green assemblages’. This approach draws inspiration from recent attempts to bring actor-network theory (ANT) closer to urban studies, infusing urban political economies with STS sensibility towards the contingencies of eco-socio-technical design and transformation processes. ANT, I argue, off ers a new ontology for the city, allowing the study of those concrete and plural sites at which urban sustainability is known, practiced, scaled, negotiated and contested, in heterogeneous and dynamic assemblages of humans and non-humans. I explore the analytical potentials of this ANT urban ontology through a case study of how architects, engineers, and urban planners currently perform Nordhavn, one of Europe’s large scale sustainable city building projects, as a site of multiple matters of public-political concern with urban natures.
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BROWN, GARETT M. „LITHOLOGICAL AND PALEOCOMMUNITY VARIATION ON A MISSISSIPPIAN (TOURNAISIAN) CARBONATE RAMP, MONTANA, USA“. PALAIOS 36, Nr. 3 (30.03.2021): 95–114. http://dx.doi.org/10.2110/palo.2020.050.
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ABSTRACT The ecological structure of ancient marine communities is impacted by the environmental gradients controlling assemblage compositions and the heterogeneous distribution of sediment types. Closely spaced, replicate sampling of fauna has been suggested to mitigate the effects of such heterogeneity and improve gradient analyses, but this technique has rarely been combined with similar sampling of lithologic data. This study analyses lithological and faunal data to determine the environmental gradients controlling the composition of Mississippian fossil assemblages of the lower Madison Group in Montana. Eighty-one lithological and faunal samples were collected from four stratigraphic columns in Montana, which represent the deep-subtidal, foreshoal, and ooid-shoal depositional environments within one third-order depositional sequence. Cluster analysis identifies three distinct lithological associations across all depositional environments—crinoid-dominated carbonates, peloidal-crinoidal carbonates, and micritic-crinoidal carbonates. Cluster analysis and nonmetric multidimensional scaling (NMS) identifies a highly diverse brachiopod biofacies and a solitary coral-dominated biofacies along an onshore-offshore gradient. Carbonate point count data and orientation of solitary corals indicate that substrate and wave energy are two potential variables that covary with the onshore-offshore gradient. Overlaying lithological information on the NMS indicates a secondary gradient reflecting oxygen that is expressed by increasing bioturbation and gradation from brown to dark gray carbonates to medium-light gray carbonates. Taken together, these findings demonstrates how combining closely spaced, replicate sampling of lithologic and faunal data enhances multivariate analyses by uncovering underlying environmental gradients that control the variation in fossil assemblages.
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Pertierra, L. R., F. Lara, P. Tejedo, A. Quesada und J. Benayas. „Rapid denudation processes in cryptogamic communities from Maritime Antarctica subjected to human trampling“. Antarctic Science 25, Nr. 2 (20.03.2013): 318–28. http://dx.doi.org/10.1017/s095410201200082x.
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AbstractThis study explores the impact of human trampling on moss and lichen dominated communities of Maritime Antarctica. A simulation of trampling was performed on previously unaffected plots of different terricolous cryptogamic assemblages at Byers Peninsula, Livingston Island. The communities studied were: 1) a uniform moss carpet, 2) a heterogeneous moss assemblage composed of hummocks and turfs, and 3) a fellfield lichen community. All communities analysed were extremely sensitive but different denudation processes were observed. None of the plots maintained 50% of initial coverage after 200 pedestrian transits. Even very low trampling intensity resulted in disturbance at all plots. Sensitivities of the different communities were identified in order to formulate recommendations for minimizing the trampling impacts. In our study the lichen dominated community on dry exposed soils exhibited the lowest resistance to trampling. For moss communities, lower resistance was found in peat soils with higher water content and biomass. With the current trend of increasing human presence in Antarctica, we predict that the cumulative impacts of trampling over future decades will adversely affect all types of moss and lichen communities.
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Hansen, Rikke Reisner, Oskar Liset Pryds Hansen, Joseph J. Bowden, Urs A. Treier, Signe Normand und Toke Høye. „Meter scale variation in shrub dominance and soil moisture structure Arctic arthropod communities“. PeerJ 4 (14.07.2016): e2224. http://dx.doi.org/10.7717/peerj.2224.
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The Arctic is warming at twice the rate of the rest of the world. This impacts Arctic species both directly, through increased temperatures, and indirectly, through structural changes in their habitats. Species are expected to exhibit idiosyncratic responses to structural change, which calls for detailed investigations at the species and community level. Here, we investigate how arthropod assemblages of spiders and beetles respond to variation in habitat structure at small spatial scales. We sampled transitions in shrub dominance and soil moisture between three different habitats (fen, dwarf shrub heath, and tall shrub tundra) at three different sites along a fjord gradient in southwest Greenland, using yellow pitfall cups. We identified 2,547 individuals belonging to 47 species. We used species richness estimation, indicator species analysis and latent variable modeling to examine differences in arthropod community structure in response to habitat variation at local (within site) and regional scales (between sites). We estimated species responses to the environment by fitting species-specific generalized linear models with environmental covariates. Species assemblages were segregated at the habitat and site level. Each habitat hosted significant indicator species, and species richness and diversity were significantly lower in fen habitats. Assemblage patterns were significantly linked to changes in soil moisture and vegetation height, as well as geographic location. We show that meter-scale variation among habitats affects arthropod community structure, supporting the notion that the Arctic tundra is a heterogeneous environment. To gain sufficient insight into temporal biodiversity change, we require studies of species distributions detailing species habitat preferences.
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Gibran, Fernando Zaniolo, und Rodrigo Leão de Moura. „The structure of rocky reef fish assemblages across a nearshore to coastal islands' gradient in Southeastern Brazil“. Neotropical Ichthyology 10, Nr. 2 (28.06.2012): 369–82. http://dx.doi.org/10.1590/s1679-62252012005000013.
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Local assemblages of fishes associated with reefs are influenced by interactions among the availability of larvae and survival of recruits with subsequent biotic and abiotic forcing, as well as by periodic and episodic disturbances of varying natures and magnitudes. Therefore, besides being structurally heterogeneous and patchily distributed, reef systems are strongly context-dependent due to the influence of a broad array of ecological processes. In order to assess interactions of local factors that influence the distribution and abundance of reef fishes within a coastal mosaic of rocky reefs, we tested the null hypothesis of no significant variation in fish assemblage structure, by comparing 33 sites along the northern coast of the São Paulo State, Southeastern Brazil. Replicated stationary visual census samples (n = 396) were obtained at different distances from the coast, depths and wave exposures, including the mainland, three relatively small coastal islands, and the two margins of a wide channel between the mainland and the large São Sebastião Island (~350 km²), totaling 225 h of SCUBA diving. The regional rocky shore fish fauna comprised 106 species (41 families), with preponderance of diurnal mobile-invertebrate feeders. Samples from the outer margin of the São Sebastião Island, together with those from Alcatrazes, Búzios, and Vitória islands were significantly dissimilar from samples from the coastal sites at the São Sebastião Channel. Species richness tended to increase in a gradient from the coast to the more offshore islands. Local conditions such as depth and other habitat characteristics also influenced fish assemblages' structure. Distance from coast and depth were the main predictors for fish assemblages, followed by water transparency, temperature and benthic cover. This study represents the first regional-scale assessment of fish assemblages associated with rocky reefs in the São Paulo State coast, filling a major geographic knowledge gap in the South Atlantic. As the study region is experiencing fast coastal development and growing threats from seaport expansion, oil and gas exploitation, as well as increasing fishing and tourism pressure, the understanding of the underlying factors that influence the distribution and abundance of the reef-associated biota comprises a relevant baseline for monitoring, conservation planning and management.
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Blaser, Mario. „Ontology and indigeneity: on the political ontology of heterogeneous assemblages“. cultural geographies 21, Nr. 1 (04.10.2012): 49–58. http://dx.doi.org/10.1177/1474474012462534.
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Amend, Anthony S., Daniel J. Barshis und Thomas A. Oliver. „Coral-associated marine fungi form novel lineages and heterogeneous assemblages“. ISME Journal 6, Nr. 7 (22.12.2011): 1291–301. http://dx.doi.org/10.1038/ismej.2011.193.
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Hardage, B. A., J. L. Simmons, V. M. Pendleton, B. A. Stubbs und B. J. Uszynski. „3-D seismic imaging and interpretation of Brushy Canyon slope and basin thin‐bed reservoirs, northwest Delaware Basin“. GEOPHYSICS 63, Nr. 5 (September 1998): 1507–19. http://dx.doi.org/10.1190/1.1444447.
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A study was done at Nash Draw field, Eddy County, New Mexico, to demonstrate how engineering, drilling, geologic, geophysical, and petrophysical technologies should be integrated to improve oil recovery from Brushy Canyon reservoirs at depths of approximately 6600 ft (2000 m) on the northwest slope of the Delaware basin. These thin‐bed reservoirs were deposited in a slope‐basin environment by a mechanism debated by researchers, a common model being turbidite deposition. In this paper, we describe how state‐of‐the‐art 3-D seismic data were acquired, interpreted, integrated with other reservoir data, and then used to improve the sitting of in‐field wells and to provide facies parameters for reservoir simulation across this complex depositional system. The 3-D seismic field program was an onshore subsalt imaging effort because the Ochoan Rustler/Salado, a high‐velocity salt/anhydrite section, extended from the surface to a depth of approximately 3000 ft (900 m) across the entire study area. The primary imaging targets were heterogenous siltstone and fine‐grained sandstone successions approximately 100 ft (30 m) thick and comprised of complex assemblages of thin lobe‐like deposits having individual thickness of 3 to 6 ft (1 to 2 m). The seismic acquisition was complicated further by (1) the presence of active potash mines around and beneath the 3-D grid that were being worked at depths of 500 to 600 ft (150 to 180 m), (2) shallow salt lakes, and (3) numerous archeological sites. We show that by careful presurvey wave testing and attention to detail during data processing, thin‐bed reservoirs in this portion of the Delaware basin can be imaged with a signal bandwidth of 10 to 100 Hz and that siltstone/sandstone successions 100 ft (30 m) thick in the basal Brushy Canyon interval can be individually detected and interpreted. Further, we show that amplitude attributes extracted from these 3-D data are valuable indicators of the amount of net pay and porosity‐feet in the major reservoir successions and of the variations in the fluid transmissivity observed in production wells across the field. Relationships between seismic reflection amplitude and reservoir properties determined at the initial calibration wells have been used to site and drill two production wells. The first well found excellent reservoir conditions; the second well was slightly mispositioned relative to the targeted reflection‐amplitude trend and penetrated reservoir facies typical of that at other producing wells. Relationships between seismic reflection amplitude and critical petrophysical properties of the thin‐bed reservoirs have also allowed a seismic‐driven simulation of reservoir performance to be initiated.
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Kerimov, Tapdyg Kh. „“New Materialism” in Sociology: Ontological Consequences“. Vestnik Tomskogo gosudarstvennogo universiteta, Nr. 462 (2021): 56–62. http://dx.doi.org/10.17223/15617793/462/7.
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The aim of this article is to provide a critical account for the ontological consequences of “new materialism” in sociology. The author explicates the context of the emergence of “new materialism”. In juxtaposition of materialism in mainstream sociology and social constructivism, “new materialism” significantly extends the sphere of materialistic analysis. It looks at the matter not as a pure container of the form, a pure passivity, but is rewarded with the features of energetism, vitalism and generative capacities. The author discloses the content of “new materialism” through reference to its three requirements: the processuality, eventfulness of the material world; the single nature-culture continuum; the extension of the capacity to act to non-human objects. In sum, all these requirements provide presuppositions for the “flat ontology” of assemblages that is opposed to mainstream sociology. The latter, with its principles of essentialism, reductionism and deontology of objects, postulates the existence of autonomous and self-sufficient sociality. In contrast, in new materialistic ontology none of the substances can be taken as an essence of the social, which entails the affirmation of the heterogeneity and multiplicity of the social. Heterogeneous assemblages appear as a primary ontological unit. Erosion of the social, its ontological devaluation as a separate sphere of reality, leads to the fact that notions of the social and social ontology become problematic. The article reveals ontological dead ends in the identification of assemblages and in the description of their social and materialistic content. The possibility of assemblage identification shows that ontologization of multiplicity can be only a new version of essentialism. The argument of the article is that there are three interpretations of assemblages, distinguished in terms of their material and social content. The first one allows the existence of matter out of social forms, but denies the possibility of its cognition and thus restores the dualism of matter-in-itself and matter-for-ourselves, of nature and society. The second one denies the existence of matter out of social forms, but thus becomes anthropocentric, which contradicts to the initial requirements of “new materialism”. The third interpretation is based on the idea of the independence of matter from social forms, but in such a version “new materialism” does not differ from mainstream sociology. The ontological dead ends of the “new materialism” bare the alternative between the disciplinary and post-disciplinary identities of sociology in the situation of a dynamic and relational social reality.
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Adams, Justin W. „Fossil mammals from the Gondolin Dump A ex situ hominin deposits, South Africa“. PeerJ 6 (06.08.2018): e5393. http://dx.doi.org/10.7717/peerj.5393.
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The Gondolin palaeokarstic system, located in the UNESCO Fossil Hominids of South Africa World Heritage Site, has been sporadically excavated since the 1970s. Sampling of ex situ dumpsites in 1997 recovered the only two fossil hominin specimens recovered thus far from Gondolin. While one partial mandibular molar (GA 1) remains unattributed, the complete mandibular second molar (GA 2) represents the largest Paranthropus robustus Broom, 1938 tooth identified to date. While subsequent excavations and research at Gondolin has clarified the geological, temporal, taphonomic, and palaeoecologic context for the in situ deposits, this paper presents the first comprehensive description of the fossil assemblage ‘associated’ with the two ex situ hominins. Analysis of 42 calcified sediment blocks and naturally decalcified sediments excavated from three cubic metres of the Dump A deposits reinforce that the dump contains a heterogeneous aggregation of materials from across the Gondolin sedimentary deposits. A total of 15,250 individual fossil specimens were processed (via sifting or acetic-acid mediated processing of calcified sediment blocks), yielding a faunal record that largely mirrors that described from either (or both) the GD 1 and GD 2 in situ assemblages but includes representatives of four novel mammal groups (Families Cercopithecidae, Felidae, Herpestidae, Giraffidae) not recorded in either in situ sample. While basic assemblage characteristics including primary taphonomic data is presented, analysis and interpretation is limited by the ex situ origin of the sample. Ultimately, these results reinforce that the substantial mining-mediated obliteration of palaeokarstic deposits at Gondolin continue to obscure a clear association between the Gondolin Dump A hominins and any of the sampled and dated in situ deposits.
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Lawson, James R., Kirstie A. Fryirs, Tanja Lenz und Michelle R. Leishman. „Heterogeneous flows foster heterogeneous assemblages: relationships between functional diversity and hydrological heterogeneity in riparian plant communities“. Freshwater Biology 60, Nr. 11 (22.07.2015): 2208–25. http://dx.doi.org/10.1111/fwb.12649.
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Bernard, S., T. A. Probyn und A. Quirantes. „Simulating the optical properties of phytoplankton cells using a two-layered spherical geometry“. Biogeosciences Discussions 6, Nr. 1 (30.01.2009): 1497–563. http://dx.doi.org/10.5194/bgd-6-1497-2009.
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Abstract. Effective use of ocean colour and other bio-optical observations is dependent upon an ability to understand and characterise the angular scattering properties of phytoplankton populations. The two-layered sphere appears to offer the simplest heterogeneous geometry capable of simulating the observed angular scattering of phytoplankton cells. A study is made of the twolayered spherical model for the simulation of the inherent optical properties of algal populations, with a particular focus on backscattering as causal to ocean colour. Homogenous and two-layered volume-equivalent single particle models are used to examine the effects of varying cellular geometry, chloroplast volume, and complex refractive index on optical efficiency factors. A morphology with a chloroplast layer surrounding the cytoplasm is shown to be optimal for algal cell simulation. Appropriate chloroplast volume and refractive index ranges, and means of determining complex refractive indices for cellular chloroplast and cytoplasm material, are discussed with regard to available literature. The approach is expanded to polydispersed populations using equivalent size distribution models: to demonstrate variability in simulated inherent optical properties for phytoplankton assemblages of changing dominant cell size and functional type. Finally, a preliminary validation is conducted of inherent optical properties determined for natural phytoplankton populations with the two-layered model, using the reflectance approximation. The study demonstrates the validity of the two-layered geometry and refractive index structure, and indicates that the combined use of equivalent size distributions with the heterogeneous geometry can be used to establish a quantitative formulation between single particle optics, size and assemblage-specific inherent optical properties, and ocean colour.
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Tworek, Stanisław. „Factors Affecting Temporal Dynamics of Avian Assemblages in a Heterogeneous Landscape“. Acta Ornithologica 39, Nr. 2 (Dezember 2004): 155–63. http://dx.doi.org/10.3161/068.039.0201.
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Rodríguez-Olarte, Douglas, Ahyran Amaro, Jorge Coronel und Donald C. Taphorn B. „Integrity of fluvial fish communities is subject to environmental gradients in mountain streams, Sierra de Aroa, north Caribbean coast, Venezuela“. Neotropical Ichthyology 4, Nr. 3 (September 2006): 319–28. http://dx.doi.org/10.1590/s1679-62252006000300003.
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We examined physical habitat and fish assemblages in rivers of the Aroa Mountains (Venezuela) with different levels of environmental protection due to the creation of Yurubí National Park within the drainage. We developed an Index of Biotic Integrity (IBI) and evaluated it using principal components analysis (PCA) and canonical correspondence analysis (CCA). Tributary rivers were divided into classes according to their origin (protected by the park) and physical characteristics of each, including substrate. Fishes were captured using standardized electrofishing. Fish communities showed greater species richness in heterogeneous habitat and protected rivers but overall abundance was higher in unprotected and impacted rivers. The IBI was sensitive to these differences and the scores were higher in protected rivers. The IBI detected degree of disturbance of fish communities without direct consideration of habitat parameters measured. The PCA revealed a gradient in substrate heterogeneity. Similarly, CCA revealed differences in fish assemblage composition along the environmental gradient and that varied with protection status of the river. The relationship between PCA and IBI scores was highly significant (r² = 0.61, P < 0.0001). The PCA and CCA analysis moderately validated the structure and predictability of IBI; but it is still necessary to refine the model and to extend its application for more time and over a wider area.
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Mayrhofer, G., R. H. Andrews, P. L. Ey und N. B. Chilton. „Division of Giardia isolates from humans into two genetically distinct assemblages by electrophoretic analysis of enzymes encoded at 27 loci and comparison with Giardia muris“. Parasitology 111, Nr. 1 (Juli 1995): 11–17. http://dx.doi.org/10.1017/s0031182000064556.
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SUMMARYGiardia that infect humans are known to be heterogeneous but they are assigned currently to a single species, Giardia intestinalis (syn. G. lamblia). The genetic differences that exist within G. intestinalis have not yet been assessed quantitatively and neither have they been compared in magnitude with those that exist between G. intestinalis and species that are morphologically similar (G. duodenalis) or morphologically distinct (e.g. G. muris). In this study, 60 Australian isolates of G. intestinalis were analysed electrophoretically at 27 enzyme loci and compared with G. muris and a feline isolate of G. duodenalis. Isolates of G. intestinalis were distinct genetically from both G. muris (approximately 80% fixed allelic differences) and the feline G. duodenalis isolate (approximately 75% fixed allelic differences). The G. intestinalis isolates were extremely heterogeneous but they fell into 2 major genetic assemblages, separated by fixed allelic differences at approximately 60% of loci examined. The magnitude of the genetic differences between the G. intestinalis assemblages approached the level that distinguished the G. duodenalis isolate from the morphologically distinct G. muris. This raises important questions about the evolutionary relationships of the assemblages with Homo sapiens, the possibility of ancient or contemporary transmission from animal hosts to humans and the biogeographical origins of the two clusters.
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Strauch, Bettina, Martin Zimmer, Axel Zirkler, Stefan Höntzsch und Anja M. Schleicher. „The influence of gas and humidity on the mineralogy of various salt compositions – implications for natural and technical caverns“. Advances in Geosciences 45 (29.08.2018): 227–33. http://dx.doi.org/10.5194/adgeo-45-227-2018.
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Abstract. Storage caverns are increasingly located in heterogeneous salt deposits and filled with various fluids. The knowledge of phase behaviour in heterogeneous systems of salt, liquid and gas and the requirements for reliable analytical techniques is, therefore, of growing interest. A method that allows for the continuous monitoring of mineral compositions at distinct humidity and gas content using XRD measurements is presented here. Various saliniferous mineral compositions have been investigated in pure CO2, N2 or CH4 atmospheres with varying humidity in a closed chamber. All mineral compositions experience dissolution and/or mineral conversion reaction accompanied by volume loss. Dissolution-recrystallization reactions of complex mineral assemblages involving halite, sylvite, kieserite, carnallite and kainite were observed using this method. For carnallite-rich mineral assemblages, the mineral conversion from carnallite to sylvite was observed when humidity exceeded 50 % RH. In the presence of CO2, acidification of the aqueous phase occurs which enhances the dissolution rate and reaction kinetics.
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Bustamante, María, Francisco Javier Tajadura-Martín und José Ignacio Saiz-Salinas. „Temporal and spatial variability on rocky intertidal macrofaunal assemblages affected by an oil spill (Basque coast, northern Spain)“. Journal of the Marine Biological Association of the United Kingdom 90, Nr. 7 (20.04.2010): 1305–17. http://dx.doi.org/10.1017/s0025315410000056.
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A large (100 km) rocky coast intertidal was sampled several times (from 2004 to 2006) to assess the affection degree of invertebrate assemblages impacted by a continuous oil spill. Twelve locations and two intertidal heights were selected along the coast representing two spatial scales (kilometres and tens of metres). Univariate and multivariate analyses of variance were used to test whether faunal assemblages exposed to different intensities of oil disturbance differ in terms of diversity, total cover, key species cover and trophic guilds. Whereas no significant differences in midshore assemblages were noted, the low intertidal zone exhibited comparatively lower abundance values of the limpet Patella ulyssiponensis at worst affected sites. Besides, a generalized increasing diversity trend was found in the low intertidal from 2004 to 2006. Natural variability of communities is also discussed as the cause of the differences we observed. With respect to spatial and temporal scales of variation, mid- intertidal communities showed a more consistent structure, while lowshore assemblages were markedly heterogeneous in practically all the variables measured.
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Kim, Eun-Sung. „Heterogeneous assemblages of bioethics and science: the “pre-embryo” debate in America“. New Genetics and Society 27, Nr. 4 (Dezember 2008): 323–37. http://dx.doi.org/10.1080/14636770802485418.
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Braicovich, P. E., und J. T. Timi. „Homogeneity of parasite assemblages of Dules auriga (Serranidae) in hydrographically heterogeneous sites“. Journal of Fish Biology 86, Nr. 4 (April 2015): 1363–76. http://dx.doi.org/10.1111/jfb.12648.
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