Relevant bibliographies by topics / Environmental niche

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Environmental niche'

Author: Grafiati
Published: 4 June 2021
Last updated: 2 February 2022

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Journal articles on the topic "Environmental niche"

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Cooper, Natalie, Rob P. Freckleton, and Walter Jetz. "Phylogenetic conservatism of environmental niches in mammals." Proceedings of the Royal Society B: Biological Sciences 278, no. 1716 (January 5, 2011): 2384–91. http://dx.doi.org/10.1098/rspb.2010.2207.

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Phylogenetic niche conservatism is the pattern where close relatives occupy similar niches, whereas distant relatives are more dissimilar. We suggest that niche conservatism will vary across clades in relation to their characteristics. Specifically, we investigate how conservatism of environmental niches varies among mammals according to their latitude, range size, body size and specialization. We use the Brownian rate parameter, σ 2 , to measure the rate of evolution in key variables related to the ecological niche and define the more conserved group as the one with the slower rate of evolution. We find that tropical, small-ranged and specialized mammals have more conserved thermal niches than temperate, large-ranged or generalized mammals. Partitioning niche conservatism into its spatial and phylogenetic components, we find that spatial effects on niche variables are generally greater than phylogenetic effects. This suggests that recent evolution and dispersal have more influence on species' niches than more distant evolutionary events. These results have implications for our understanding of the role of niche conservatism in species richness patterns and for gauging the potential for species to adapt to global change.
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Figueiredo, Giovanna Corrêa e., Karina Bohrer do Amaral, and Marcos César de Oliveira Santos. "Cetaceans along the southeastern Brazilian coast: occurrence, distribution and niche inference at local scale." PeerJ 8 (October 5, 2020): e10000. http://dx.doi.org/10.7717/peerj.10000.

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It is deemed important to understand cetacean occurrence and distribution to comprehend their ecological roles. The geographical occurrence of species’ niche can be used to better describe their potential distribution. The niche can be defined using environmental variables. Those variables are considered static and not affected by biological activities. The present study goal was to assess the occurrence and distribution of cetaceans along the southeastern Brazilian coast, as well as to define the fundamental and realized niche of each species and to investigate niche overlap at local scale. The environmental requirements for each species were also investigated throughout statistical tests. Sighting data were obtained through oceanographic surveys conducted between 2012 and 2015. The environmental variables available on MARSPEC and the software NicheA were used for the ecological niche modeling. A total of twelve cetacean species were identified and the potential distribution areas of the six commonest ones were defined. Even though the species presented different environmental preferences, most of them had partial overlap among niches and potential distribution areas. The environmental heterogeneity of the study area might support the co-occurrence of different species with different environmental requirements.
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Litsios, Glenn, Loïc Pellissier, Félix Forest, Christian Lexer, Peter B. Pearman, Niklaus E. Zimmermann, and Nicolas Salamin. "Trophic specialization influences the rate of environmental niche evolution in damselfishes (Pomacentridae)." Proceedings of the Royal Society B: Biological Sciences 279, no. 1743 (June 20, 2012): 3662–69. http://dx.doi.org/10.1098/rspb.2012.1140.

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The rate of environmental niche evolution describes the capability of species to explore the available environmental space and is known to vary among species owing to lineage-specific factors. Trophic specialization is a main force driving species evolution and is responsible for classical examples of adaptive radiations in fishes. We investigate the effect of trophic specialization on the rate of environmental niche evolution in the damselfish, Pomacentridae, which is an important family of tropical reef fishes. First, phylogenetic niche conservatism is not detected in the family using a standard test of phylogenetic signal, and we demonstrate that the environmental niches of damselfishes that differ in trophic specialization are not equivalent while they still overlap at their mean values. Second, we estimate the relative rates of niche evolution on the phylogenetic tree and show the heterogeneity among rates of environmental niche evolution of the three trophic groups. We suggest that behavioural characteristics related to trophic specialization can constrain the evolution of the environmental niche and lead to conserved niches in specialist lineages. Our results show the extent of influence of several traits on the evolution of the environmental niche and shed new light on the evolution of damselfishes, which is a key lineage in current efforts to conserve biodiversity in coral reefs.
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Ramírez-Albores, Jorge E., Gustavo Bizama, Ramiro O. Bustamante, and Ernesto I. Badano. "Niche conservatism in a plant with long invasion history: the case of the Peruvian peppertree (Schinus molle, Anacardiaceae) in Mexico." Plant Ecology and Evolution 153, no. 1 (March 26, 2020): 3–11. http://dx.doi.org/10.5091/plecevo.2020.1562.

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Background and aim – Invasive plants should only colonize habitats meeting the environmental conditions included in their native niches. However, if they invade habitats with novel environmental conditions, this can induce shifts in their niches. This may occur in plants with long invasion histories because they interacted with the environmental conditions of invaded regions over long periods of time. We focused on this issue and evaluated whether the niche of the oldest plant invader reported in Mexico, the Peruvian peppertree, is still conserved after almost 500 years of invasion history. Methods – We compared climatic niches of the species between the native and invaded region. We later used species distribution models (SDM) to visualize the geographical expression of both niches in Mexico. Results – The invasive niche of the Peruvian peppertree is fully nested within the native niche. Although this suggests that the niche is conserved, this also indicates that a large fraction of the native niche is empty in the invaded region. The SDM from the native region indicated that Mexico contains habitats meeting the conditions included in this empty fraction of the native niche and, thus, this invasion should continue expanding. Nevertheless, the SDM calibrated with data from the invaded region indicated that peppertrees have colonized all suitable habitats indicated by its invasive niche and, thus, their populations should no longer expand. Conclusion – Our results suggests that the niche of the Peruvian peppertree is partially conserved in Mexico. This may have occurred because individuals introduced into Mexico constituted a small, nonrepresentative sample of the full niche of the species.
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Warren, Dan L., Richard E. Glor, and Michael Turelli. "ENVIRONMENTAL NICHE EQUIVALENCY VERSUS CONSERVATISM: QUANTITATIVE APPROACHES TO NICHE EVOLUTION." Evolution 62, no. 11 (November 2008): 2868–83. http://dx.doi.org/10.1111/j.1558-5646.2008.00482.x.

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Pagel, Jörn, Martina Treurnicht, William J. Bond, Tineke Kraaij, Henning Nottebrock, AnneLise Schutte-Vlok, Jeanne Tonnabel, Karen J. Esler, and Frank M. Schurr. "Mismatches between demographic niches and geographic distributions are strongest in poorly dispersed and highly persistent plant species." Proceedings of the National Academy of Sciences 117, no. 7 (February 6, 2020): 3663–69. http://dx.doi.org/10.1073/pnas.1908684117.

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The ecological niche of a species describes the variation in population growth rates along environmental gradients that drives geographic range dynamics. Niches are thus central for understanding and forecasting species’ geographic distributions. However, theory predicts that migration limitation, source–sink dynamics, and time-lagged local extinction can cause mismatches between niches and geographic distributions. It is still unclear how relevant these niche–distribution mismatches are for biodiversity dynamics and how they depend on species life-history traits. This is mainly due to a lack of the comprehensive, range-wide demographic data needed to directly infer ecological niches for multiple species. Here we quantify niches from extensive demographic measurements along environmental gradients across the geographic ranges of 26 plant species (Proteaceae; South Africa). We then test whether life history explains variation in species’ niches and niche–distribution mismatches. Niches are generally wider for species with high seed dispersal or persistence abilities. Life-history traits also explain the considerable interspecific variation in niche–distribution mismatches: poorer dispersers are absent from larger parts of their potential geographic ranges, whereas species with higher persistence ability more frequently occupy environments outside their ecological niche. Our study thus identifies major demographic and functional determinants of species’ niches and geographic distributions. It highlights that the inference of ecological niches from geographical distributions is most problematic for poorly dispersed and highly persistent species. We conclude that the direct quantification of ecological niches from demographic responses to environmental variation is a crucial step toward a better predictive understanding of biodiversity dynamics under environmental change.
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Shenbrot, G., and B. Kryštufek. "Relation between the habitat niche breadth and the geographic range size: A case study on palearctic voles (Mammalia: Rodentia: Arvicolinae)." Povolzhskiy Journal of Ecology, no. 1 (May 18, 2021): 79–88. http://dx.doi.org/10.35885/1684-7318-2021-1-79-88.

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Habitat niche breadth for Palearctic Arvicolinae species was estimated at both local (α- niche) and global (the entire geographic range, γ-niche) scales using occurrence records of species and environmental (climate, topography, and vegetation) data. Niche breadth was estimated in the space of the first two principal components of environmental variables using kernel smoothing of the densities of species occurrence points. The breadth of α-niches was estimated for a set of random points inside the geographic range in a series of buffers of increasing size around these points. Within each buffer, we calculated the overlap between the distribution of environment values for the kernel smoothed densities of species occurrence points and the distribution of environment values in the background environment. The α-niche breadth was calculated as the slope of the linear regression of the niche breadth for buffers of different size by the ln area of these buffers with a zero intercept. The γ-niche breadth was calculated as the overlap between the distributions of environmental values for the kernel smoothed densities of species occurrence points over the whole geographic range and the distribution of environmental values in the background environment and also approximated by linear regression of the species’ average α-niche to the geographic range area of this species. The results demonstrated that the geographic range size was significantly related with the α- and γ-niche breadth. The γ-niche breadth was significantly positively correlated with the α-niche breadth. Finally, the differences between the γ-niche breadth values that were directly estimated and extrapolated from the α-niche breadth (Δ) values were positively correlated with the geographic range size. Thus, we conclude that the species occupy larger geographic ranges because they have broader niches. Our estimations of the γ-niche breadth increase with the geographic range size not due to a parallel increase of the environmental diversity (spatial autocorrelation in the environment).
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Acanski, Jelena, Marija Milicic, Laura Likov, Dubravka Milic, Snezana Radenkovic, and Ante Vujic. "Environmental niche divergence of species from Merodon ruficornis group (Diptera: Syrphidae)." Archives of Biological Sciences 69, no. 2 (2017): 247–59. http://dx.doi.org/10.2298/abs160303095a.

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In this paper we analyzed environmental differentiation of closely related species from the Merodon ruficornis group. By applying principal component analysis (PCA) and environmental niche modelling (ENM)-based techniques, we estimated the level of niche divergence of closely related species. Our results indicate that ecology has an important role in the diversification process in related species from the M. ruficornis group. Distribution patterns of all analyzed species are mainly affected by the limiting effects of the temperature of the coldest quarter and month, as well as by the precipitation of the wettest and driest quarters. Our results demonstrated that among all related species, with the exception of M. ovaloides, overall or partial divergence in environmental space is present. Importantly, the results indicate that the environmental niches of all endemic species are restricted to smaller parts of the environmental space. In the case of niche overlap, the niches of endemic species are placed along the border of the realized niche of the widespread related species. For species in which distribution is not limited by geographical barriers, environmental preferences could be considered as limiting factors for further expansion, as in the case of M. alexandri, a lowland species with very strict climatic adaptations. Knowledge about the environmental factors that might influence the diversification process can provide an explanation for the high diversity in other Merodon species groups.
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Walker, Richard. "“Niche Selection” and the Evolution of Complex Behavior in a Changing Environment—A Simulation." Artificial Life 5, no. 3 (July 1999): 271–89. http://dx.doi.org/10.1162/106454699568782.

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One of the key problems in theoretical biology is the identification of the mechanisms underlying the evolution of complexity. This paper suggests that some difficulties in current models could be avoided by taking account of “niche selection” as proposed by Waddington [21] and subsequent authors [2]. Computer simulations, in which an evolving population of artificial organisms “selects” the niche(s) that maximize their fitness, are compared with a Control Model in which “Niche Selection” is absent. In the simulations the Niche Selection Model consistently produced a greater number of “fit” organisms than the Control Model; although the Niche Selection Model tended, in general, to produce organisms occupying simple niches, it was nonetheless more effective than the Control Model in producing well-adapted organisms inhabiting complex niches. It is shown that the production of these organisms is critically dependent on the rate of environmental change: Slow change leads to fit but undifferentiated populations, dominated by organisms occupying simple niches; differentiated populations, including well-adapted organisms living in complex niches, require rates of environmental change lying just beyond a mathematically well-defined critical value. In simulation “Niche Selection,” unlike conventional “Natural Selection,” provides a permanent selective bias in favor of simplicity. This tendency is counterbalanced by statistical forces favoring shifts from rare “simple niches” to commoner niches of greater complexity. Fit organisms inhabiting complex niches only emerge in conditions where the rate of environmental change is high enough to avoid the concentration of the population in very simple niches, but slow enough to permit step-by-step adaptation to niches of gradually increasing complexity. This result appears to be robust to changes in simulation parameters and assumptions, and leads to interesting conjectures about the real world behavior of biological organisms (and other complex adaptive systems). It is suggested that some of these conjectures might be relatively easy to test.
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Bar-Massada, Avi. "Complex relationships between species niches and environmental heterogeneity affect species co-occurrence patterns in modelled and real communities." Proceedings of the Royal Society B: Biological Sciences 282, no. 1813 (August 22, 2015): 20150927. http://dx.doi.org/10.1098/rspb.2015.0927.

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Species co-occurrence analysis is commonly used to assess how interspecific interactions dictate community assembly. Non-random co-occurrences, however, may also emerge from niche differences as well as environmental heterogeneity. The relationships between species co-occurrence patterns, environmental heterogeneity and species niches are not fully understood, due to complex interactions among them. To analyse the relationships among these patterns and processes, I developed synthetic community models and analysed a large dataset of tree species across the conterminous United States. Niche overlap and environmental heterogeneity had significant and contrasting effects on species co-occurrence patterns, in both modelled and real communities. Niche breadth, in turn, affected the effect sizes of both variables on species co-occurrence patterns. The effect of niche breadth on the relationship between co-occurrence and niche overlap was markedly consistent between modelled and real communities, while its effect on the relationship between co-occurrence and environmental heterogeneity was mostly consistent between real and modelled data. The results of this analysis highlight the complex and interactive effects of species niche overlap, niche breadth and environmental heterogeneity on species co-occurrence patterns. Therefore, inferring ecological processes from co-occurrence patterns without accounting for these fundamental characteristics of species and environments may lead to biased conclusions.
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Dissertations / Theses on the topic "Environmental niche"

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Milne, Margaret Georgina. "Environmental niche evolution and ancestral niche reconstruction." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709832.

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Quantifying the diversity and distribution of the world’s biota in both space and time is a fundamental goal of modern biology, however ecologists also face the added pressure of understanding how species may respond to anthropogenically driven environmental changes. The relationship between species distributions and the environment can be captured in Environmental Niche Models (ENM’s), which create mathematical models linking species occurrences to ecological factors at a specific point in time. Whilst this approach is very useful, it can be improved by the incorporation of phylogenetic data (with estimated species divergence dates) to explore how the environmental niche has changed for a whole clade through evolutionary time. This thesis aims to explore whether niches are conserved over the life history for individual species, and for entire genera through evolutionary time. The research aims to firstly improve the current iteration of the Coleopteran Mutual Climatic Range (MCR) approach by automating the climate envelope creation process; secondly, to determine whether the expression of the realised climate niche has changed for four members of the Staphylinid Olophrum genus through the Quaternary and thirdly, to create a historical bio-geographical model indicating the likely mode of evolution between sister-taxa in the Dytiscidae Hydroporus genus. Lastly, the ancestral climatic niche of the Hydroporus genus is modelled in order to determine any patterns in climate niche evolution. This is achieved by bringing together phylogenetic data, occurrence data and environmental data under a Bayesian analysis framework to reconstruct the values for environmental niche traits at internal nodes in a phylogenetic tree.
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Russell, Vanessa. "Identifying Environmental Factors Driving Differences in Climatic Niche Overlap in Peromyscus Mice." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1565722438217428.

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O'Rourke, Eamonn Christopher. "Natural building in South Africa : assessing the niche-regime relationship through a 'latent niche' mediation." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96704.

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Thesis (MPhil)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: In this thesis I examine the natural building movement in South Africa in an attempt to determine the systemic influences that appear to confine it to a small market operating at the very edge of the mainstream building sector. I make use of the conceptual framework of the multi-level perspective to explore the interrelationships between natural building as a technological niche and the mainstream building sector as the dominant regime. I extend the concept of a technological niche by appending the term 'latent' to form the term 'latent technological niche', to describe a technology with sustainability credentials that fails to break into the mainstream market, despite achieving technological maturity and constant though minimal market share. The research objectives of this thesis are to: identify pathways for the natural building niche to move beyond its latent state; to determine how the translations of natural building practices to the building sector might occur; and how this might transform the building sector regime. I explore how action research involving knowledge sharing between multi-stakeholder, niche and regime actors might stimulate debate and subsequent action to overcome entry barriers; and serve as a catalyst to advance a latent technological niche beyond its confined market. I present an action research method, a 'latent technological mediation', of facilitated 1st and 2nd order social learning. This is used as a mechanism of tapping into the immediate knowledge of actors in the socio-technical regime. The purpose being to identify the external forces and internal processes of a latent technological niche. The status of a latent technological niche is assessed by comparing these processes in the context of external forces against seven processes, presented in this thesis. These seven processes are considered crucial for a technology to break into the mainstream market and are adapted from the internal processes of success, described in the literature on strategic niche management and the characteristics of a successful 'bounded socio-technical experiment' (BSTE) described in the conceptual work on BSTE's. The potential for natural building systems to enter the mainstream building sector, particularly in South Africa, is used as a case study to apply the latent technological mediation method. The findings of this research suggest that the mainstream building sector is undergoing a transition following the path of socio-techical transformation. The uncertainty introduced by the parallel system of informal settlement, which may drive transition along the more dramatic technological substitution or de-alignment and re-alignment transition pathways is briefly explored.
AFRIKAANSE OPSOMMING: In hierdie tesis ondersoek ek die natuurlike gebou beweging in Suid-Afrika in 'n poging om die sistemiese invloede te bepaal, wat neig om dit te beperk tot 'n klein mark teen die rand van die hoofstroom gebou sektor. Ek maak gebruik van die konseptuele raamwerk van die multi-vlak perspektief om die onderlinge verband tussen natuurlike geboue, as 'n tegnologiese nis, en die hoofstroom gebou sektor, as die dominante regime, te verken. Ek brei die konsep van 'n tegnologiese nis uit, deur die aanbring van die word 'latente' om die term 'latente tegnologiese nis' te vorm. 'n Latente tegnologie nis het volhoubaarheid potensiaal maar slaag nie daarin om in die hoofstroom mark in te breek nie, ten spyte van die bereiking van tegnologiese volwassenheid en 'n konstante maar minimale mark aandeel. Die navorsing doelwitte van hierdie tesis is om: roetes te identifiseer waarlangs die natuurlike gebou nis buite sy latente toestand kan beweeg; om te bepaal hoe die 'vertalings' van natuurlike gebou praktyke aan die gebou sektor kan voorkom; en hoe dit die gebou sektor regime kan verander. Ek bestudeer hoe aksie navorsing waarby kennis tussen verskeie belanghebbendes, nis en regime betrokkenes gedeel is, kan debatteer en die daaropvolgende aksie stimuleer inskrywing hindernisse te oorkom; en dien as 'n katalisator om 'n latente tegnologiese nis te bevorder buite sy beperkte mark. Ek bied 'n aksie-navorsing metode, 'n 'latente tegnologiese bemiddeling' van gefasiliteerde 1st en 2de order sosiale leerervaring aan. Dit dien as 'n meganisme van deling in die onmiddellike kennis van die spelers in die sosio-tegniese regime. Die doel is om die eksterne kragte en interne prosesse van 'n latente tegnologiese nis te identifiseer. Die status van 'n latente tegnologiese nis is beoordeel deur hierdie prosesse te vergelyk in die konteks van eksterne kragte teen sewe prosesse, wat in hierdie tesis aangebied is. Hierdie sewe prosesse word beskou as noodsaaklik vir 'n tegnologie om in die hoofstroom mark in te breek en is aangepas uit die interne prosesse van sukses, soos beskryf in die literatuur oor strategiese nis bestuur en die eienskappe van 'n suksesvolle 'begrensde sosio-tegniese eksperiment' (BSTE) beskryf in die konseptuele literatuur oor BSTE. Die potensiaal vir natuurlike gebou stelsels om die hoofstroom gebou sektor te betree, veral in Suid-Afrika, word gebruik as 'n gevallestudie om die latente tegnologiese bemiddeling metode toe te pas. Die bevindinge van die navorsing dui daarop dat die hoofstroom gebou sektor 'n verandering ondergaan op die pad van n sosio-tegniese transformasie. Die onsekerheid veroorsaak deur die parallelle informele nedersetting, wat 'n meer dramatiese tegnologiese substitusie, of ontsporing en herbelyning kan veroorsaak, word kortliks ondersoek.
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Purcell, Ceara K. Q. "How do Ecological Niches Evolve during Late Ordovician Environmental Change? A Test using Laurentian Brachiopods." Ohio University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1616426713257168.

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Bublys, Kasparas. "Diet variability in Eurasian perch (Perca fluviatilis) as a response to environmental variables along a latitudinal gradient." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-365794.

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Climate change is expected to have a profound impact on freshwater fish communities, especially at higher latitudes. In this study I investigated potential effects of climate change on the niche structure of Eurasian perch (Perca fluviatilis) by looking at their diet across a latitudinal gradient and at varying light climate. Dietary niche width of Eurasian perch did not differ significantly between boreal and temperate latitudes. Additionally, no significant difference in the prevalence of specialist individuals was found along the latitudinal gradient and water transparency levels. Habitat was the main factor that significantly affected niche width and level of specialization with both being significantly higher in the littoral habitat. Taken together my results suggest that climate change might indirectly affect niche patterns by altering fish densities through changes in productivity resulting in niche and specialization variation among habitats.
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Brame, Hannah-Maria R. "Are Cincinnatian (Late Ordovician) Niche Stability Responses to Variable Environmental Changes Congruent Across Clades, Taxonomic Scales, and Through Time?" Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1366634147.

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Wilson, C. Elizabeth. "The environmental niche of Aboriginal infants, possible implications for sudden infant death syndrome." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ35048.pdf.

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Benmimoun, Billel. "Le contrôle micro-environmental de l'homéostasie du système sanguin de la larve de drosophile." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/3439/.

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L'homéostasie du système sanguin est préservée grâce à une régulation très fine de la balance entre le maintien et la différenciation des cellules souches hématopoïétiques et de leurs descendances. Cet équilibre est régulé par une relation complexe de signaux intrinsèques (cellulaires autonomes) issus de la cellule elle-même et de signaux extrinsèques (cellulaires non-autonomes) issus des cellules voisines (microenvironnement) et de l'environnement (tels que les conditions nutritionnelles ou la présence de pathogènes). La dérégulation de l'équilibre du système hématopoïétique est à l'origine de nombreuses pathologies chez l'homme dont des leucémies. Au cours de ma thèse, je me suis attaché à décrypter et à comprendre dans quelle mesure et par quels mécanismes ces facteurs extrinsèques du microenvironnement et de l'environnement influencent le destin des précurseurs hématopoïétiques et l'homéostasie du système sanguin. Je me suis plus précisément concentré sur l'impact de la nutrition et la voie de signalisation Insuline/TOR ainsi que sur le rôle d'un microenvironnement spécialisé appelé " la niche hématopoïétique " dans le maintien indifférencié des progéniteurs sanguins de la larve de Drosophile. Différents aspects du développement des cellules sanguines sont conservés de la Drosophile aux mammifères aussi bien d'un point de vue ontogénique et fonctionnel que par l'implication de régulateurs transcriptionnels et voies de signalisations similaires. Plus particulièrement, l'organe hématopoïétique de la larve de Drosophile appelé " glande lymphatique ", qui contient à la fois des progéniteurs sanguins et leurs descendances, s'est illustré comme un excellent modèle pour décrypter les bases moléculaires et les mécanismes intra et extracellulaires qui contrôlent le destin des cellules hématopoïétiques et ainsi l'équilibre du système sanguin. Dans cet organe, les progéniteurs hématopoïétiques, appelés également prohémocytes, forment la Zone Médullaire et se différencient dans la Zone Corticale. La glande lymphatique présente également une troisième zone appelée Centre de Signalisation Postérieur (PSC) exprimant le facteur de transcription de type EBF/Collier et proposée comme niche hématopoïétique. Mon premier projet de thèse consistait à étudier l'impact de la nutrition et de la voie de signalisation Insuline/TOR dans le contrôle de l'homéostasie de la glande lymphatique. En effet, adapter le développement et l'homéostasie des tissus aux conditions nutritionnelles et au stress métabolique représente un enjeu majeur pour chaque organisme. Par des expériences de perte et de gain de fonction dirigées, nous avons montré que la voie de signalisation Insuline/TOR contrôle l'homéostasie de la glande lymphatique en agissant à la fois sur la croissance du PSC et de manière cellulaire autonome sur le destin des précurseurs hématopoïétiques. De plus, les expériences de carence nutritionnelle mettent en évidence un contrôle nutritionnel du devenir des progéniteurs sanguins. Ainsi, nous avons montré pour la première fois que la signalisation Insuline/TOR relie le maintien de l'homéostasie du système sanguin aux conditions nutritionnelles de la larve de Drosophile. Mon deuxième projet de thèse consistait à étudier le rôle du PSC (microenvironnement) proposé comme niche hématopoïétique dans le maintien de l'homéostasie de la glande lymphatique. En effet, les communications dynamiques entre les cellules souches et leurs microenvironnements jouent un rôle crucial dans le maintien de l'homéostasie des tissus. Par l'ablation génétique du PSC, nos résultats montrent clairement que le PSC n'est pas requis pour le maintien de l'état indifférencié des progéniteurs hématopoïétiques. De plus, l'inhibition ciblée du facteur de transcription Collier/EBF dans les progéniteurs hématopoïétiques est suffisante pour induire leur différenciation précoce. Ainsi, nos résultats suggèrent un nouveau modèle de régulation du système hématopoïétique de la larve de Drosophile ; indépendant du PSC mais qui fait appel à une fonction cellulaire autonome de Collier/EBF dans les progéniteurs sanguins
The homeostasis of the haematopoietic system is maintained through a very fine control of the balance between the maintenance and the differentiation of haematopoietic stem cells and their progeny. This balance is regulated by a complex relationship of intrinsic signals (cell autonomous factors) provided by the cell itself and extrinsic signals (non cell autonomous factors) arising from neighbouring cells (microenvironment) and environmental cues (e. G. Nutrition or infection by pathogen) The deregulation of blood system homeostasis causes many human diseases including leukaemia. During my PhD, I tried to decipher by which mechanisms these extrinsic signals impact on haematopoietic progenitor fate and blood system homeostasis. I focused on the impact of nutrition and the role of the Insulin/TOR signalling pathway as well as on the role of a specialized microenvironment called the haematopoietic niche on the maintenance of Drosophila larval blood progenitors. Different aspects of blood cell development are conserved from Drosophila to mammals including ontogenic and functional conservation as well as involvement of similar transcriptional regulators and signalling pathways. More particularly, the Drosophila larval haematopoietic organ called " lymph gland ", which contains both blood progenitors and their progeny, has emerged as an excellent model to decipher the molecular basis and the intra/extracellular mechanisms that control blood cell fate and blood system homeostasis. In this organ, hematopoietic progenitors, also called prohaemocytes form the Medullary Zone and differentiate in a peripheral area called the Cortical Zone. The lymph gland presents also a third cluster of cells, called the Posterior Signalling Centre (PSC), expressing the transcription factor EBF/Collier and proposed to act as a haematopoietic niche. My first project was to investigate the impact of nutrition and the role of the Insulin/TOR signalling pathway on the control of lymph gland homeostasis. In fact, adapting development and tissue homeostasis to nutritional conditions and metabolic stress is a major challenge for every organism. Using site-directed loss- and gain-of-function analysis, we demonstrated that Insulin/TOR signalling controls lymph gland homeostasis by acting both on PSC growth and cell-autonomously on blood cell progenitor fate. Moreover, starvation experiments highlighted the nutritional control of hematopoietic progenitor maintenance. Thereby, we showed for the first time that Insulin/TOR signalling pathway connects blood system homeostasis to the Drosophila larval nutritional conditions. In my second project, I reinvestigated the role of the PSC (microenvironment), which was proposed to act as hematopoietic niche required for prohemocyte maintenance. Indeed, the dynamic communication between stem cells and their microenvironment plays a crucial role in maintaining tissue homeostasis. In contrast with the prevailing model, our genetic ablation experiments clearly demonstrate that the PSC is not required for Drosophila haematopoietic progenitor maintenance. Moreover, the targeted inhibition of the transcription factor Collier/EBF in the progenitor population is sufficient to cause their precocious differentiation. Thereby, we propose a new model of Drosophila haematopoietic progenitor maintenance, which is independent of the PSC but relies on the cell-autonomous function of the transcription factor EBF/Collier in these cells
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Plourde, Laura. "Environmental niche partitioning among riparian sedges (Carex, Cyperaceae) in the St. Lawrence Valley, Quebec." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112344.

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To understand maintenance of the within-habitat diversity of closely related species, I investigated 11 Carex species growing along rivers in the south-western St. Lawrence Valley of Quebec. Microenvironments within a half meter of focal plants characterized for Carex comosa, C. crinita, C. grayi, C. intumescens, C. lacustris, C. lupulina, C. pseudocyperus, C. retrorsa, C. tuckermanii, C. typhina, and C. vesicaria revealed significant differences among the species in their environmental affinities. Species appear to fall into groups based on their tolerance of flooding and are secondarily differentiated on other environmental gradients such as insolation, soil pH and soil organic matter. Several traits were related to the environments that species inhabit: diaspore weight, diaspore floating duration, and root aerenchyma. The absence of any phylogenetic trend in niche differences for pairs of species supports the idea that evolutionary differentiation of the alpha-niche is the basis for coexistence of congeners.
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Georgian, Sam Ellis. "ENVIRONMENTAL AND ENERGETIC CONSTRAINTS ON COLD-WATER CORALS." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/382890.

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Biology
Ph.D.
Cold-water corals act as critical foundation species in the deep sea by creating extensive three-dimensional habitat structures that support biodiversity hotspots. There is currently a paucity of data concerning the environmental requirements and physiology of cold-water corals, severely limiting our ability to predict how resilient they will be to future environmental change. Cold-water corals are expected to be particularly vulnerable to the effects of ocean acidification, the reduction in seawater pH and associated changes to the carbonate system caused by anthropogenic CO2 emissions. Here, the ecological niche and physiology of the cold-water coral Lophelia pertusa is explored to predict its sensitivity to ocean acidification. Species distribution models were generated in order to quantify L. pertusa’s niche in the Gulf of Mexico with regard to parameters including seafloor topography, the carbonate system, and the availability of hard substrate. A robust oceanographic assessment of the Gulf of Mexico was conducted in order to characterize the current environmental conditions at benthic sites, with a focus on establishing the baseline carbonate system in L. pertusa habitats. Finally, an experimental approach was used to test the physiological response of biogeographically separated L. pertusa populations from the Gulf of Mexico and the Norwegian coast to ocean acidification. Based on my findings, it appears that L. pertusa already persists near the edge of its viable niche space in some locations, and therefore may be highly vulnerable to environmental change. However, experimental results suggest that some populations may be surprisingly resilient to ocean acidification, yielding broad implications for the continued persistence of cold-water corals in future oceans.
Temple University--Theses
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Books on the topic "Environmental niche"

1

Kaufman, Donald G. Finding our niche: The human role in healing the earth. New York: Harper Collins College Publishers, 1993.

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Cellura, A. Raymond. The genomic environment and niche-experience. Abbeville, SC: Cedar Springs Press, 2004.

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Cellura, A. Raymond. The genomic environment and niche-experience. Abbeville, SC: Cedar Springs Press, 2005.

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Weber, Jörg. Die Erde ist nicht Untertan: Grundrechte der Natur. Frankfurt/Main: Eichborn, 1993.

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Kagaku Gijutsu no Mirai o Tenbōsuru Senryaku Wākushoppu (2004 Tokyo, Japan). Kagaku Gijutsu no Mirai o Tenbōsuru Wākushoppu: Kankyō bunʼya ni okeru kongo no kadai to hōsaku (2004-nen 1-gatsu 23-nichi--24-nichi kaisai) : hōkokusho. Tōkyō: Kagaku Gijutsu Shinkō Kikō Kenkyū Kaihatsu Senryaku Sentā Inoue Jōseki Ferō Gurūpu, 2004.

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Kagaku, Gijutsu no Mirai o. Tenbōsuru Senryaku Wākushoppu (2004 Tokyo Japan). Kagaku Gijutsu no Mirai o Tenbōsuru Wākushoppu: Kankyō bunʼya ni okeru kongo no kadai to hōsaku (2004-nen 1-gatsu 23-nichi--24-nichi kaisai) : hōkokusho. Tōkyō: Kagaku Gijutsu Shinkō Kikō Kenkyū Kaihatsu Senryaku Sentā Inoue Jōseki Ferō Gurūpu, 2004.

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Scarlato, Francisco Capuano. Do nicho ao lixo: Ambiente, sociedade e educação. São Paulo, SP: Atual Editor, 1992.

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Huan jing bao hu bu huan jing gong cheng ping gu zhong xin (China). Hokutō Ajia kankyō kanri ni kansuru Nichi-Chu-Kan kyōdō kenkyū hōkokusho. [Japan: s.n.], 2009.

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Kaisha, Idea Kabushiki. Kagaku busshitsu no naibunpi kakuran sayō ni kansuru Nichi-Ei Nichi-Bei nikokukan kyōryoku oyobi OECD tō e no kokusai kyōryoku suishin ni kakaru gyōmu: Nichi-Ei kyōdō kenkyū seika hōkokusho : Heisei 22-nendo. Tōkyō: Idea, 2011.

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Wagner, Wilhelm J. Österreichs reale Utopien: Viel geplant und nicht verwirklicht. Wien: K & S, Kremayr & Scheriau, 2000.

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Book chapters on the topic "Environmental niche"

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Tang, Duozhuang. "Niche-Stem Cell Interactions and Environmental Influences." In Else Kröner-Fresenius Symposia, 87–91. Basel: S. KARGER AG, 2012. http://dx.doi.org/10.1159/000339386.

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Cayla, Nathalie, and Heidi Elisabeth Megerle. "Dinosaur Geotourism in Europe, a Booming Tourism Niche." In Advances in Geographical and Environmental Sciences, 359–79. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4956-4_19.

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Mukherjee, Somnath, and Uma Sankar Malik. "Socio-ecological Niche of Tribes of Purulia District, West Bengal, India." In Advances in Asian Human-Environmental Research, 179–92. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-49115-4_10.

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Hurst, Christon J. "Our Living World Rests upon a Foundation of Microorganisms: The Constant Struggle for Habitat and Niche." In Advances in Environmental Microbiology, 3–18. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63512-1_1.

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Pinto-Ledezma, Jesús N., and Jeannine Cavender-Bares. "Using Remote Sensing for Modeling and Monitoring Species Distributions." In Remote Sensing of Plant Biodiversity, 199–223. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-33157-3_9.

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AbstractInterpolated climate surfaces have been widely used to predict species distributions and develop environmental niche models. However, the spatial coverage and density of meteorological sites used to develop these surfaces vary among countries and regions, such that the most biodiverse regions often have the most sparsely sampled climatic data. We explore the potential of satellite remote sensing (S-RS) products—which have consistently high spatial and temporal resolution and nearly global coverage—to quantify species-environment relationships that predict species distributions. We propose several new environmental metrics that take advantage of high temporal resolution in S-RS data and compare these approaches to classic climate-only approaches using the live oaks (Quercus section Virentes) as a case study. We show that models perform similarly but for some species, particularly in understudied regions, show less precision in predicting spatial distribution. These results provide evidence supporting efforts to enhance environmental niche models and species distribution models (ENMs/SDMs) with S-RS data and, when combined with other approaches for species detection, will likely enhance our ability to monitor biodiversity globally.
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Pauly, Klaas, and Olivier De Clerck. "GIS-Based Environmental Analysis, Remote Sensing, and Niche Modeling of Seaweed Communities." In Cellular Origin, Life in Extreme Habitats and Astrobiology, 93–114. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8569-6_6.

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Bajaj, Shaurya, and D. Geraldine Bessie Amali. "Species Environmental Niche Distribution Modeling for Panthera Tigris Tigris ‘Royal Bengal Tiger’ Using Machine Learning." In Emerging Research in Computing, Information, Communication and Applications, 251–63. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-5953-8_22.

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Childress, R. Brooks, Leon A. Bennun, and David M. Harper. "Population changes in sympatric Great and Long-tailed Cormorants (Phalacrocorax carbo and P. africanus): the effects of niche overlap or environmental change?" In Lake Naivasha, Kenya, 163–70. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-017-2031-1_16.

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Wilhelm, Erik, Wilfried Hahn, and Martin Kyburz. "KYBURZ Small Electric Vehicles: A Case Study in Successful Deployment." In Small Electric Vehicles, 143–55. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-65843-4_11.

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AbstractThis paper is written from the perspective of a Swiss OEM which has been active in the small electric vehicle (SEV) market since 1991 and has put over 22,000 SEVs on the road around the world. KYBURZ Switzerland AG identified several important niche markets for SEVs and today sells vehicles to improve the mobility of senior citizens (e.g. KYBURZ Plus), to increase the efficiency of postal and logistics companies (e.g., KYBURZ DXP), and to imbue drivers with passion for electric vehicles (e.g., KYBURZ eRod). Most KYBURZ vehicles are currently homologated in the category L2e, L6e, or L7e. The company has also developed a Fleet Management product which gives its customers detailed insights into the performance of their electric as well as conventionally powered vehicles. Anonymized datasets from this Fleet Management system will be drawn upon in this paper to examine questions regarding their application, i.e., environmental and economic aspects. The unique feature which the authors from KYBURZ bring with this paper is that all their investigations are performed with real data gained from the field experience. The primary focus of this paper is on last-mile mobility services for postal organizations which help to increase efficiency and meet sustainability goals.
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Wang, Alex B., Prachi Jain, and Tudorita Tumbar. "The Hair Follicle Stem Cell Niche: The Bulge and Its Environment." In Tissue-Specific Stem Cell Niche, 1–26. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-21705-5_1.

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Conference papers on the topic "Environmental niche"

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Honghua, Shi, Zheng Wei, and Gao Meng. "Human Niche Models and Their Application in Internal Migration in China." In 2009 International Conference on Environmental Science and Information Application Technology, ESIAT. IEEE, 2009. http://dx.doi.org/10.1109/esiat.2009.386.

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HuangLeichang, Chenying, YeShuhong, and Guolin. "The application and theory of niche of concentrative region of tourism resource." In 2010 2nd Conference on Environmental Science and Information Application Technology (ESIAT). IEEE, 2010. http://dx.doi.org/10.1109/esiat.2010.5568963.

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Banaszek, Jarosław, Marzena Leksy, and Oimahmad Rahmonov. "The ecological diversity of vegetation within urban parks in the Dąbrowski Basin (southern Poland)." In Environmental Engineering. VGTU Technika, 2017. http://dx.doi.org/10.3846/enviro.2017.005.

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The aim of this work is to present the diversity of flora in terms of ecological requirements. The research was conducted in the area of two urban parks in the area of two cities in southern Poland: Bedzin and Czeladz. These parks were established in different historical periods, and were planned (and are managed) differently. The results of the investigation have shown that the occurrence of 192 vascular species has been observed in the Gora Zamkowa (Castle Hill) Park, while in the Grabek park, 334 such species are known to exist. Such disparity is the result of the occurrence of micro-habitats and of the differences between the ways the two parks are managed. It is also due to these parks’ different functions. In the first case, the park area is protected by law. In the latter case, human activity has created a new ecological niche for organisms with a high degree of ecological tolerance. Based on the ecological values, the following groups of plants were distinguished: saxi-frages grasslands, xerothermic grasslands, beech forests, alder forests and artificial planted trees. Analysis has shown that ur-ban parks are potential places for growth various type of vegetation and also for increasing biodiversity, and can constitute particularly important hotspots for biodiversity in the cityscape, even if their primary role is recreational. As the study shows, the environment of a highly urbanized and industrialized region can also have a positive influence on ecological and floristic diversity.
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Barbosa, Fábio C. "Hyperloop Concept Technological and Operational Review: The Potential to Fill Rail Niche Markets." In 2020 Joint Rail Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/jrc2020-8033.

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Abstract The modern society’s continuous increasing mobility requirements have encouraged new transportation technological platforms. The so called Hyperloop concept, also described as the fifth mode of transport (rather than road, rail, water and air) for both passenger and/or freight) is supported on the idea of a pod like vehicle, running in a near vacuum environment (inside tubes) at near sonic speeds, higher than current air transport ones. This technological approach has played a prominent role in the modern transport scenario, with a potential to offer high service levels, associated with high speed, reliability and weather operational flexibility, as well as reduced environmental footprint and costs. This groundbreaking technological concept, albeit revolutionary, can not be seen as a novelty, with previous precursors being proposed in the last century. However, the concept has been reintroduced in 2012 with updated technologies, in an open sourced format, by the acknowledged entrepreneur Elon Musk, to instigate further improvement/development among interested companies worldwide, focused on its exploration on a commercial scale in the near future. The Hyperloop concept is envisioned to compete with both the High Speed Rail (HSR) and Maglev services, in the 160–640 km (100–400 mi) range, as well as air transport, for up to 1,000 km (625 mi) range, with alleged both environmental and cost advantages over their competitors. However, despite the technology’s high performance potential, given its multidisciplinary feature (sonic/high speed, near vacuum, linear motor propulsion, electric power storage, pod environment maintenance/cooling, air quality control, transport capacity, among others) and its inherent current low maturity from both the engineering, operational and cost perspectives, there are several major technological, regulatory, planning, financial and environmental challenges to be addressed, prior to reach the commercial service status. In this context, it is currently required a huge research effort to figure out technological barriers, followed by prototype tests, to set up the safety and operational requirements. Work is current under way, with a huge research effort (from both the academy and the industry) focused on basic technological concepts, as well as some prototype tests (currently unmanned) driven to test the specific main technological approaches in a real world condition. Given its revolutionary feature, Hyperloop technology is seemed as both ambitious and controversial by the general public and transport experts, with some optimistic bets in its medium term revolutionary role in the passenger transport market, focused on some niche segments currently serviced by the rail mode, as well as other skeptical bets in its restricted role to the freight market, given some inherent safety issues. This work is supposed to present a review (supported on the current available technical literature) of the groundbreaking Hyperloop technology concept and its potential to fill some specific rail niche markets, in both passenger and/or freight segments, with an assessment of the main technology’s hurdles/bottlenecks status and their perspectives, from a technological, environmental and cost focus, followed by a snapshot of some potential Hyperloop project candidates.
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Myers, Corinne, and Agathe Carrier. "TESTING NICHE STABILITY IN WESTERN INTERIOR SEAWAY CEPHALOPODS AND OTHER MOLLUSKS ACROSS THE ENVIRONMENTAL PERTURBATION OF OAE2." In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-323668.

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Sviridova, O. V., N. I. Vorobyov, Ya V. Pukhalsky, O. N. Kurchak, O. P. Onishchuk, V. I. Safronova, I. G. Kuznetsova, and V. N. Pishchik. "Ability of the soil cellulolytic bacteria to colonize endophytic niche of barley grains." In РАЦИОНАЛЬНОЕ ИСПОЛЬЗОВАНИЕ ПРИРОДНЫХ РЕСУРСОВ В АГРОЦЕНОЗАХ. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2020. http://dx.doi.org/10.33952/2542-0720-15.05.2020.20.

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To identify microorganisms that can penetrate into the endophytic niche of the grain of barley plants, many years of vegetative experiments were conducted on sod-podzolic soil without the use of mineral fertilizers. In the non-growing season, a biological product, consisting of cellulolytic association of bacteria with genotypic passport, decomposed barley straw. Presowing treatment of seeds was not carried out, therefore, during the growing season; local microorganisms decomposing plant residues could be present in the barley rhizosphere. After six years of rotation of barley plants, the microbiological composition of its seed niche was studied. As a result, it was found that in the seeds of barley bacteria are present in an amount of 240 ± 20 CFU/g of grain. Isolated pure cultures of microorganisms were identified as Cellulomonas gelida, Micrococcus luteus and Bacillus licheniformis by the sequence of ITS fragments of 16S rRNA. These types of bacteria were also present in the used biological product. Based on the research conducted, it can be assumed, that permanent cultivation of barley plants and sowing of seeds of the previous year can contribute to the formation of effective microbial and plant biosystems that are resistant to environmental stress.
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Zhao, Yuan, Jianfeng Xu, and Deborah Thurston. "A Hierarchical Bayesian Method for Market Positioning in Environmentally Conscious Design." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-47898.

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Environmentally conscious consumers and environmental protection legislation have been driving manufacturers to design, produce, and dispose products in a more environmentally responsible manner. One of the key issues is how to position environmentally conscious products in the marketplace. Environmentally conscious design eventually needs to make the transition into mainstream design, rather than stay in a high-profile niche application. The assumption that all consumers have the same preferences does not hold in the real marketplace. Heterogeneous customer preferences require analysis of customer choice behavior at the individual level. In addition, individual customer preferences can be clustered into aggregate preferences of different market segments that are latent within the customer base. In this paper, a Hierarchical Bayesian method is presented to integrate individual level preference information, which can be used to help manufacturers measure product attribute weights and identify appropriate market segments in which customers value the environmentally conscious design the most. An automobile design case study is used to demonstrate the proposed approach.
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Adenan, Sakeenah, Jane Oja, Talaat Abdel-Fattah, and Juha Alatalo. "Linking Soil Chemical Parameters and Fungal Diversity in Qatar." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0068.

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Given the vast expanse of Qatar’s dryland ecosystems, agricultural productivity and soil stability is highly dependent on the diversity of soil microbiota. The soil environment is a heterogeneous habitat shaped by various components like chemical (organic matter, salinity and nutrients) and biological (fungal diversity and vegetation) properties that form multitudes of different microhabitats. Soil microbial diversity changes along environmental gradients. It is hypothesized that a “stable” microhabitat is one that is inhabited by a large diversity of established microorganisms that are best adapted to the niche. Microorganisms like fungi serve as the underlying biological drivers for biochemical processes within the soil. The key objective of this study is to evaluate the fungal diversity and abundance present within the Qatari soil using molecular-based tools and evaluate potential relationships between the identified fungal communities with chemical properties of the habitat. We found that the composition of fungi and AMF varied between different habitats around Qatar. Despite the lack of significant differences in the measured soil chemical parameters between sampled sites, it is evident that AMF species are more abundant than compared to that of other fungal species in most of the study sites; thus, suggesting that other factors like land use may also be an essential component explaining the variation in fungal communities.
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Mason, J. Brad, and Corey A. Myers. "THOR® Steam Reforming Technology for the Treatment of Ion Exchange Resins and More Complex Wastes Such as Fuel Reprocessing Wastes." In ASME 2010 13th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2010. http://dx.doi.org/10.1115/icem2010-40165.

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The THOR® fluidized bed steam reforming process has been successfully operated for more than 10 years in the United States for the treatment of low- and intermediate-level radioactive wastes generated by commercial nuclear power plants. The principle waste stream that has been treated is ion exchange resins (IER) and Dry Active Waste (DAW), but various liquids, sludges, and solid organic wastes have also been treated. The principle advantages of the THOR® process include: (a) high volume reduction on the order of 5:1 to 10:1 for IER and up to 50:1 for high plastic content DAW streams depending on the waste type and waste characteristics, (b) environmentally compliant off-gas emissions, (c) reliable conversion of wastes into mineralized products that are durable and leach-resistant, and (d) no liquid effluents for treatment of most radioactive wastes. Over the past ten years, the THOR® process has been adapted for the treatment of more complex wastes including historic defense wastes, reprocessing wastes, and other wastes associated with the fuel cycle. As part of the U.S. Department of Energy (DOE) environmental remediation activities, the THOR® dual bed steam reforming process has successfully processed: (a) Idaho National Laboratory (INL) Sodium-Bearing Waste (SBW), (b) Savannah River Tank 48 High Level Waste (HLW), (c) Hanford Low Activity Waste (LAW), and (d) Hanford Waste Treatment Plant Secondary Waste (WTP-SW) liquid slurry simulants. The THOR® process has been shown in pilot plant operations to successfully process various simulated liquid, radioactive, nitrate-containing wastes into environmentally safe, leach-resistant, solid mineralized products. These mineralized products incorporate normally soluble ions (e.g. - Na, K, Cs, Tc), sulfates, chloride salts, and fluoride salts into an alkali alumino-silicate mineral matrix that inhibits the leaching of those ions into the environment. The solid mineralized products produced by the THOR® process exhibit durability and leach resistance characteristics superior to borosilicate waste glasses. As a result of this work, a full-scale THOR® process facility is currently under construction at the DOE’s Idaho site for the treatment of SBW and a full-scale facility is in the final design stage for the DOE’s Savannah River Site for the treatment of Tank 48 high level waste. Recent work has focused on the development of new monolithic waste formulations, the extension of the THOR® process to new waste streams, and the development of modular THOR® processes for niche waste treatment applications. This paper will provide an overview of current THOR® projects and summarize the processes and outcomes of the regulatory and safety reviews that have been necessary for the THOR® process to gain acceptance in the USA.
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10

Abdel Samad, Rim, Zulfa Al Disi, Mohammad Ashfaq, and Nabil Zouari. "The use of Principle Component Analysis and MALDI-TOF MS for the differentiation of mineral forming Virgibacillus and Bacillus species isolated from Sabkhas." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0069.

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Occurrence of mineral forming and other bacteria in mats is well demonstrated. However, their high diversity shown by ribotyping was not explained, although it could explain the diversity of formed minerals. Common biomarkers as well as phylogenic relationships are useful tools to clustering the isolates and predict their potential role in the natural niche. In this study, combination of MALDI-TOF MS with PCA was shown a powerful tool to categorize 35 mineral forming bacterial strains isolated from Dohat Fshaikh sabkha, at northwest of Qatar (23 from decaying mats and 12 from living ones). 23 strains from decaying mats belong to Virgibacillus genus as identified by ribotyping and are shown highly involved in formation of protodolomite and a diversity of minerals. They were used as internal references in categorization of sabkha bacteria. Combination of isolation of bacteria on selective mineral forming media, their MALDI TOF MS protein profiling and PCA analysis established their relationship in a phyloproteomic based on protein biomarkers including m/z 4905, 3265, 5240, 6430, 7765, and 9815. PCA analysis clustered the studied strains into 3 major clusters, showing strong correspondence to the 3 phyloproteiomic groups that were established by the dendrogram. Both clustering analysis means have evidently demonstrated a relationship between known Virgibacillus strains and other related bacteria based on profiling of their synthesized proteins. Thus, larger populations of bacteria in mats can be easily screened for their potential to exhibit certain activities, which is of ecological, environmental and biotechnological significance.
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Reports on the topic "Environmental niche"

1

Exploring the Prospects of Using 3D Printing Technology in the South African Human Settlements. Academy of Science of South Africa (ASSAf), 2021. http://dx.doi.org/10.17159/assaf.2021/0074.

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South Africa is a country with significant socio-economic development challenges, with the majority of South Africans having limited or non-existent access to basic infrastructure, services, housing and socio-economic opportunities etc. The urban housing backlog currently exceeds 2.4 million houses, with many families living in informal settlements. The Breaking New Grounds Policy, 2014 for the creation of sustainable human settlements, acknowledges the challenges facing human settlements, such as, decreasing human settlements grants allocation, increasing housing backlog, mushrooming of informal settlements and urbanisation. The White Paper on Science, Technology and Innovation (STI), 2019 notes that South Africa has not yet fully benefited from the potential of STI in addressing the socio-economic challenges and seeks to support the circular economy principles which entail a systematic change of moving to a zero or low waste resource-efficient society. Further to this, the Science and Technology Roadmap’s intention is to unlock the potential of South Africa’s human settlements for a decent standard of living through the smart uptake of science, technology and innovation. One such novel technology is the Three-Dimensional (3D) printing technology, which has produced numerous incredible structures around the world. 3D printing is a computer-controlled industrial manufacturing process which encompasses additive means of production to create 3D shapes. The effects of such a technology have a potential to change the world we live in and could subsequently pave the roadmap to improve on housing delivery and reduce the negative effects of conventional construction methods on the environment. To this end, the Academy of Science of South Africa (ASSAf), in partnership with the Department of Science and Innovation (DSI) and the University of Johannesburg (UJ) hosted the second virtual IID seminar titled: Exploring the Prospects of Using 3D Printing Technology in the South African Human Settlements, on 01 March 2021 to explore the potential use of 3D printing technology in human settlements. The webinar presented preliminary findings from a study conducted by UJ, addressing the following topics: 1. The viability of 3D printing technology 2. Cost comparison of 3D printed house to conventional construction 3. Preliminary perceptions on 3D printing of houses Speakers included: Dr Jennifer Mirembe (NDoHS), Dr Jeffrey Mahachi, Mr Refilwe Lediga, Mr Khululekani Ntakana and Dr Luxien Ariyan, all from UJ. There was a unanimous consensus that collaborative efforts from all stakeholders are key to take advantage of this niche technology. @ASSAf_Official; @dsigovza; @go2uj; @The_DHS; #SA 3D_Printing; #3D Print_Housing; #IID
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