Relevant bibliographies by topics / Alpha and beta diversity

Contents

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

Academic literature on the topic 'Alpha and beta diversity'

Author: Grafiati
Published: 4 June 2021
Last updated: 16 June 2025

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Alpha and beta diversity.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Alpha and beta diversity"

1

Hautmann, Michael. "Diversification and diversity partitioning." Paleobiology 40, no. 2 (2014): 162–76. http://dx.doi.org/10.1666/13041.

Full text
Abstract:
Model calculations predict that pathways of alpha- and beta-diversity in diversifying ecosystems notably differ depending on the relative role of competition, predation, positive effects of species' interactions, and environmental parameters. Four scenarios are discussed, in which alpha- and beta-diversity are modeled as a function of increasing gamma-diversity. The graphic illustration of this approach is herein called α-β-γ plot, in which the x-axis indicates increasing diversification rather than absolute time. In purely environmentally controlled systems, beta-diversity maintains near-maximum values throughout the diversification interval, whereas mean alpha-diversity increases linearly, with a slope being reciprocal to beta-diversity. A second scenario is based on the assumption that increasing richness will have predominantly positive effects on the addition of further species; here, alpha- and beta-diversity increase simultaneously (though not necessarily at the same rates) and without reaching a predictable upper limit. In ecosystems that are characterized by low competition between species, mean alpha-diversity asymptotically approaches a saturation level, whereas the increase in beta-diversity accelerates until alpha-diversity stagnates, and then continues to rise linearly. If competition is high, addition of species first increases beta-diversity until no further habitat contraction is possible, followed by a period in which alpha-diversity increase through adaptive divergence becomes the principal drive of diversification. Because there is a continuous transition between the late stage of the low-competition model and the early stage of the high-competition scenario, both can be combined in a single model of diversity partitioning under the premise of a diversity-dependent increase of competition. This summary model predicts three phases of diversity accumulation: (1) a niche overlap phase, (2) a habitat contraction phase, and (3) a niche differentiation phase. The models herein discussed provide a potential tool to assess the question which factors primary controlled the diversification of life over geological times.
APA, Harvard, Vancouver, ISO, and other styles
2

Kulkarni, Narendra, and Leela J. Bhosale. "Alpha - Beta Diversity Assessment of the Mangroves of Two Districts along the Coast of Maharashtra State." Plantae Scientia 4, no. 3 (2021): 168–73. http://dx.doi.org/10.32439/ps.v4i3.168-173.

Full text
Abstract:
Alpha-Beta Diversity (? and ?): During the present study the alpha and beta diversity of mangrove in the study area has been analyzed. Twenty nine estuaries from Ratnagiri and Sindhudurg districts of Maharashtra State are studied and data analyzed for calculating alpha and beta diversity.
APA, Harvard, Vancouver, ISO, and other styles
3

Patel, Pinkal, and Ratna Trivedi. "Alpha and Beta Diversity Indices of Mushrooms from Different Localities." Journal of Pure and Applied Microbiology 11, no. 3 (2017): 1577–81. http://dx.doi.org/10.22207/jpam.11.3.44.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Garcia, A., H. Solano-Rodríguez, and O. Flores-Villela. "Patterns of alpha, beta and gamma diversity of the herpetofauna in Mexico's Pacific lowlands and adjacent interior valleys." Animal Biodiversity and Conservation 30, no. 2 (2007): 169–77. http://dx.doi.org/10.32800/abc.2007.30.0169.

Full text
Abstract:
The latitudinal distribution patterns of alpha, beta and gamma diversity of reptiles, amphibians and herpetofauna were analyzed using individual binary models of potential distribution for 301 species predicted by ecological modelling for a grid of 9,932 quadrants of ~25 km2 each. We arranged quadrants in 312 latitudinal bands in which alpha, beta and gamma values were determined. Latitudinal trends of all scales of diversity were similar in all groups. Alpha and gamma responded inversely to latitude whereas beta showed a high latitudinal fluctuation due to the high number of endemic species. Alpha and gamma showed a strong correlation in all groups. Beta diversity is an important component of the herpetofauna distribution patterns as a continuous source of species diversity throughout the region.
APA, Harvard, Vancouver, ISO, and other styles
5

Fontanilla, Alyssa M., Akihiro Nakamura, Zhenghui Xu, et al. "Taxonomic and Functional Ant Diversity Along tropical, Subtropical, and Subalpine Elevational Transects in Southwest China." Insects 10, no. 5 (2019): 128. http://dx.doi.org/10.3390/insects10050128.

Full text
Abstract:
Although elevational gradients of biodiversity have long been the topic of scientific research, information on patterns of, and processes that shape insect community structure across elevation is still lacking. Addressing this gap requires the use of both taxonomic and functional approaches when studying diversity across elevational gradients. In this study, we examined taxonomic and functional alpha and beta diversity of ant assemblages sampled along tropical, subtropical, and subalpine elevational transects in Yunnan Province, southwest China. Species richness was used to quantify taxonomic alpha diversity, and two indices (FD and FRic) were calculated using morphological measurements to quantify functional alpha diversity. Taxonomic and functional beta diversity were partitioned into their turnover- and nestedness-resultant components. Though temperature and functional alpha diversity decreased linearly with increasing elevation, taxonomic alpha diversity showed a significant logarithmic decrease, with few species present at elevations greater than 3000 m a.s.l. The turnover-resultant component of taxonomic beta diversity increased with increasing elevational distance, while the nestedness-resultant component of functional beta diversity increased with increasing elevational distance in the subtropical transect. The observed patterns of taxonomic and functional diversity reflected ants’ thermophilic nature, implying functional adaptations (i.e., nested functional diversity) at higher elevations where environmental conditions were unfavorable.
APA, Harvard, Vancouver, ISO, and other styles
6

Sepkoski, J. John. "Alpha, beta, or gamma: where does all the diversity go?" Paleobiology 14, no. 3 (1988): 221–34. http://dx.doi.org/10.1017/s0094837300011969.

Full text
Abstract:
Global taxonomic richness is affected by variation in three components: within-community, or alpha, diversity; between-community, or beta, diversity; and between-region, or gamma, diversity. A data set consisting of 505 faunal lists distributed among 40 stratigraphic intervals and six environmental zones was used to investigate how variation in alpha and beta diversity influenced global diversity through the Paleozoic, and especially during the Ordovician radiations. As first shown by Bambach (1977), alpha diversity increased by 50 to 70 percent in offshore marine environments during the Ordovician and then remained essentially constant for the remainder of the Paleozoic. The increase is insufficient, however, to account for the 300 percent rise observed in global generic diversity. It is shown that beta diversity among level, soft-bottom communities also increased significantly during the early Paleozoic. This change is related to enhanced habitat selection, and presumably increased overall specialization, among diversifying taxa during the Ordovician radiations. Combined with alpha diversity, the measured change in beta diversity still accounts for only about half of the increase in global diversity. Other sources of increase are probably not related to variation in gamma diversity but rather to appearance and/or expansion of organic reefs, hardground communities, bryozoan thickets, and crinoid gardens during the Ordovician.
APA, Harvard, Vancouver, ISO, and other styles
7

Wang, Jianming, Chen Chen, Jingwen Li, Yiming Feng, and Qi Lu. "Different ecological processes determined the alpha and beta components of taxonomic, functional, and phylogenetic diversity for plant communities in dryland regions of Northwest China." PeerJ 6 (January 10, 2019): e6220. http://dx.doi.org/10.7717/peerj.6220.

Full text
Abstract:
Drylands account for more than 30% of China’s terrestrial area, while the ecological drivers of taxonomic (TD), functional (FD) and phylogenetic (PD) diversity in dryland regions have not been explored simultaneously. Therefore, we selected 36 plots of desert and 32 plots of grassland (10 × 10 m) from a typical dryland region of northwest China. We calculated the alpha and beta components of TD, FD and PD for 68 dryland plant communities using Rao quadratic entropy index, which included 233 plant species. Redundancy analyses and variation partitioning analyses were used to explore the relative influence of environmental and spatial factors on the above three facets of diversity, at the alpha and beta scales. We found that soil, climate, topography and spatial structures (principal coordinates of neighbor matrices) were significantly correlated with TD, FD and PD at both alpha and beta scales, implying that these diversity patterns are shaped by contemporary environment and spatial processes together. However, we also found that alpha diversity was predominantly regulated by spatial structure, whereas beta diversity was largely determined by environmental variables. Among environmental factors, TD was most strongly correlated with climatic factors at the alpha scale, while with soil factors at the beta scale. FD was only significantly correlated with soil factors at the alpha scale, but with altitude, soil and climatic factors at the beta scale. In contrast, PD was more strongly correlated with altitude at the alpha scale, but with soil factors at the beta scale. Environment and space explained a smaller portion of variance in PD than in TD and FD. These results provide robust evidence that the ecological drivers of biodiversity differ among different scales and facets of diversity. Future research that focuses on the comparisons among TD, FD and PD would likely provide new insights into elucidating the underlying community assembly.
APA, Harvard, Vancouver, ISO, and other styles
8

Saito, T., J. L. Sussman, J. D. Ashwell, and R. N. Germain. "Marked differences in the efficiency of expression of distinct alpha beta T cell receptor heterodimers." Journal of Immunology 143, no. 10 (1989): 3379–84. http://dx.doi.org/10.4049/jimmunol.143.10.3379.

Full text
Abstract:
Abstract Ag recognition by most T lymphocytes is mediated by clonally distributed alpha beta heterodimeric receptors. A major fraction of TCR diversity is believed to be due to the random coexpression in individual T cells of the products of independently rearranging alpha- and beta-genes (combinatorial diversity). However, analysis of cell surface receptors on transfected T hybridoma cells synthesizing various sets of alpha- and beta-chains revealed marked differences in the efficiency of expression of certain alpha beta-pairs. Specifically, using the functionally rearranged gene products of the 2B4 cytochrome c specific T hybridoma (V beta 3, V alpha 11.2) and BW5147 parent lymphoma (V beta 1, V alpha BW), a hierarchy of expression efficiency relative to indirectly measured precursor chain levels in the cell was shown to be 2B4 alpha-BW beta greater than 2B4 alpha - 2B4 beta greater than BW alpha - BW beta greater than BW alpha - 2B4 beta. The estimated difference between the best expressed and worst expressed pairs is on the order of 50-fold. For the beta-chain, the primary determinant of expression efficiency with a given alpha-chain appears to be the V segment, as a second V beta 1-chain with distinct D and J regions from BW beta was expressed with the same pattern. These data imply that alpha- and beta-chains do not form well-expressed TCR in a random manner and that limitations on the useful combinatorial association of these chains may significantly affect the functional T cell repertoire.
APA, Harvard, Vancouver, ISO, and other styles
9

Jones, Gavin M., Berry Brosi, Jason M. Evans, et al. "Conserving alpha and beta diversity in wood‐production landscapes." Conservation Biology 36, no. 3 (2022): e13872. https://doi.org/10.5281/zenodo.14822136.

Full text
Abstract:
(Uploaded by Plazi for the Bat Literature Project) International demand for wood and other forest products continues to grow rapidly, and uncertainties remain about how animal communities will respond to intensifying resource extraction associated with woody bioenergy production. We examined changes in alpha and beta diversity of bats, bees, birds, and reptiles across wood production landscapes in the southeastern United States, a biodiversity hotspot that is one of the principal sources of woody biomass globally. We sampled across a spatial gradient of paired forest landuses (representing pre and postharvest) that allowed us to evaluate biological community changes resulting from several types of biomass harvest. Short-rotation practices and residue removal following clearcuts were associated with reduced alpha diversity (−14.1 and −13.9 species, respectively) and lower beta diversity (i.e., Jaccard dissimilarity) between land-use pairs (0.46 and 0.50, respectively), whereas midrotation thinning increased alpha (+3.5 species) and beta diversity (0.59). Over the course of a stand rotation in a single location, biomass harvesting generally led to less biodiversity. Cross-taxa responses to resource extraction were poorly predicted by alpha diversity: correlations in responses between taxonomic groups were highly variable (−0.2 to 0.4) with large uncertainties. In contrast, beta diversity patterns were highly consistent and predictable across taxa, where correlations in responses between taxonomic groups were all positive (0.05–0.4) with more narrow uncertainties. Beta diversity may, therefore, be a more reliable and information-rich indicator than alpha diversity in understanding animal community response to landscape change. Patterns in beta diversity were primarily driven by turnover instead of species loss or gain, indicating that wood extraction generates habitats that support different biological communities.
APA, Harvard, Vancouver, ISO, and other styles
10

Bartha, Sándor, Roberto Canullo, Stefano Chelli, and Giandiego Campetella. "Unimodal Relationships of Understory Alpha and Beta Diversity along Chronosequence in Coppiced and Unmanaged Beech Forests." Diversity 12, no. 3 (2020): 101. http://dx.doi.org/10.3390/d12030101.

Full text
Abstract:
Patterns of diversity across spatial scales in forest successions are being overlooked, despite their importance for developing sustainable management practices. Here, we tested the recently proposed U-shaped biodiversity model of forest succession. A chronosequence of 11 stands spanning from 5 to 400 years since the last disturbance was used. Understory species presence was recorded along 200 m long transects of 20 × 20 cm quadrates. Alpha diversity (species richness, Shannon and Simpson diversity indices) and three types of beta diversity indices were assessed at multiple scales. Beta diversity was expressed by a) spatial compositional variability (number and diversity of species combinations), b) pairwise spatial turnover (between plots Sorensen, Jaccard, and Bray–Curtis dissimilarity), and c) spatial variability coefficients (CV% of alpha diversity measures). Our results supported the U-shaped model for both alpha and beta diversity. The strongest differences appeared between active and abandoned coppices. The maximum beta diversity emerged at characteristic scales of 2 m in young coppices and 10 m in later successional stages. We conclude that traditional coppice management maintains high structural diversity and heterogeneity in the understory. The similarly high beta diversities in active coppices and old-growth forests suggest the presence of microhabitats for specialist species of high conservation value.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Alpha and beta diversity"

1

Toussaint, Aurèle. "Diversité fonctionnelle des poissons d'eau douce à l'échelle mondiale : patrons, déterminants et impacts des activités humaines." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30403.

Full text
Abstract:
Pendant longtemps, la biodiversité était caractérisée uniquement par sa diversité taxonomique, c'est-à-dire par le nombre et la composition en espèces des assemblages. Cependant, de récentes études montrent que la biodiversité ne peut être résumée uniquement à cette composante, car elle ne prend pas en compte les caractéristiques écologiques des espèces. Pour cela, la diversité fonctionnelle est un outil permettant de considérer les traits fonctionnels des espèces. Peu d'études à larges échelles ont décrit cette facette de la biodiversité et son lien avec la diversité taxonomique. L'objectif de cette thèse est donc de 1) décrire et comprendre la distribution de la diversité fonctionnelle des assemblages de poissons d'eau douce à l'échelle globale et de 2) quantifier les conséquences des activités humaines sur cette facette. Pour cela, nous avons construit une base de données de traits fonctionnels de plus de 9000 espèces de poissons d'eau douce. Nous avons mis en évidence que la diversité fonctionnelle mondiale est distribuée de façon très hétérogène. Elle est essentiellement concentrée dans les bassins Néotropicaux, contrastant avec des zones taxonomiquement riches mais fonctionnellement redondantes comme l'Afrique ou l'Asie. Ces patrons pouvaient être expliqués par une diversification fonctionnelle de certains ordres de poissons Néotropicaux. À l'échelle des bassins versants, nous avons montré une faible, mais significative, influence des variables environnementales en particulier des variables historiques pour expliquer l'hétérogénéité des patrons de diversité fonctionnel des bassins versants. Nous avons également montré que les activités humaines, sous l'effet des introductions d'espèces, ont contribué à modifier considérablement les patrons de diversité fonctionnelle par rapport aux changements de diversité taxonomique. Ces changements mettent en évidence la nécessité de prendre en compte les conséquences des espèces non-natives sur le fonctionnement des écosystèmes. Dans ce travail de thèse, nous avons ainsi démontré que la diversité fonctionnelle est une facette complémentaire à la diversité taxonomique chez des poissons d'eau douce. Ces résultats contribuent à enrichir les connaissances de la structure des assemblages et peuvent avoir des implications en termes de gestion de la biodiversité<br>For a long time, biodiversity was characterised solely by its taxonomic diversity, i.e. the number and species composition of assemblages. However, recent studies show that biodiversity cannot be summed up solely by this component as it does not take into account the ecological characteristics of species. For this, functional diversity is a tool for considering the functional traits of species. Few large-scale studies have described this facet of biodiversity and its link with taxonomic diversity. The aim of this thesis is therefore to 1) describe and understand the distribution of functional diversity of freshwater fish assemblages on a global scale and 2) quantify the consequences of human activities on this facet. For this purpose, we have built a database of functional traits of more than 9000 species of freshwater fish. We have shown that the world's functional diversity is very heterogeneously distributed. It is essentially concentrated in the Neotropical basins, contrasting with taxonomically rich but functionally redundant areas such as Africa or Asia. These patterns could be explained by a functional diversification of certain orders of Neotropical fish. At the watershed scale, we showed a weak, but significant, influence of environmental variables, in particular historical variables, to explain the heterogeneity of the functional diversity patterns of watersheds. We have also shown that human activities, under the effect of species introductions, have contributed to a significant change in functional diversity patterns compared to changes in taxonomic diversity. These changes highlight the need to take into account the consequences of non-native species on ecosystem functioning. In this thesis work, we have thus demonstrated that functional diversity is a complementary facet of taxonomic diversity in freshwater fish. These results contribute to knowledge of the structure of assemblages and may have implications in terms of biodiversity management
APA, Harvard, Vancouver, ISO, and other styles
2

Noble, Sidney Lake. "The Influence of Canopy Cover and Canopy Heterogeneity on Plant Diversity within Oak Savannas." Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1595843486558554.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Mathon, Laëtitia. "L’ADN environnemental pour décrire les patrons de diversité des poissons à large échelle et informer la conservation." Electronic Thesis or Diss., Université de Montpellier (2022-....), 2023. http://www.theses.fr/2023UMONG005.

Full text
Abstract:
L’accélération des changements globaux et les impacts humains menacent la survie des communautés de poissons à l’échelle mondiale. Or ces communautés sont indispensables au bon fonctionnement des écosystèmes marins et aux populations dépendantes de la pêche. Seul un suivi efficace et rapide des communautés de poissons à petite et grande échelle pour comprendre leurs distributions, les règles d’assemblage et les impacts des pressions humaines et environnementales peut permettre d’implémenter des mesures de conservation optimales. L’ADN environnemental (ADNe) est une méthode récente, dont l’efficacité a été démontrée à échelle locale et régionale pour étudier les communautés de poissons côtiers. Cette méthode permet de pallier certains biais induits par les méthodes de suivi conventionnelles (pêche, plongée, caméras). Le but de cette thèse est d’utiliser l’ADNe pour étudier les distributions des poissons à diverses échelles spatiales, en réponse à des facteurs environnementaux, géographiques et socio-économiques, puis de nourrir les approches de planification de conservation. J’ai d’abord comparé les outils bio-informatiques fréquemment utilisés pour l’analyse des données d’ADNe, identifié les meilleurs programmes et pipelines et construit un pipeline optimal pour identifier les espèces contenues dans un échantillon, dans le cas d’une base de référence complète. Cependant, à large échelle, les bases de références sont largement incomplètes pour le gène mitochondrial 12S que nous utilisons et ne permettent donc pas l’assignation taxonomique de tous les fragments d’ADNe. Les autres études de cette thèse reposent ainsi sur une méthode de regroupement des séquences en unités taxonomiques moléculaires (MOTUs). À partir d’un jeu de données échantillonné à large échelle dans trois océans (Indien, Pacifique, Atlantique), j’ai comparé les estimations de diversité de poissons de récifs coralliens obtenues avec l’ADNe et avec des données de recensements visuels en plongée, à l’échelle de plusieurs biorégions. J’ai démontré que l’ADNe estimait une plus grande diversité de familles et de MOTUs que les plongées, tout en retrouvant les grands patrons de distributions connus (gradient longitudinal, isolation de la faune des Caraïbes). Puis, à l’échelle globale, j’ai étudié l’influence de facteurs environnementaux, géographiques et socio-économiques sur plusieurs indices de diversité alpha et bêta, à partir de plus de 500 échantillons d’ADNe prélevés dans 11 régions du monde. Les résultats montrent un effet dominant de l’environnement (température et productivité) sur la diversité alpha et bêta, mais aussi une diminution de ces diversités dans les zones proches des populations humaines et notamment dans les pays dépendant des ressources marines. Enfin, à une échelle régionale en Nouvelle Calédonie, en combinant l’ADNe avec des méthodes plus conventionnelles (caméras appâtées et échosondeur acoustique), j’ai estimé et modélisé plusieurs métriques de diversité des poissons sur les pentes externes et monts sous-marins, jusqu’à 600m de profondeur, que j’ai ensuite intégrées dans une planification de conservation en trois dimensions. Ces résultats indiquent de fortes richesses, abondances et biomasses sur les monts sous-marins peu profonds et isolés, ainsi que sur les pentes externes des îles et atolls éloignés des zones urbanisées, qui sont donc à prioriser dans les plans de conservation. L’ensemble des travaux de cette thèse démontrent l’utilité du metabarcoding de l’ADNe pour étudier la distribution des poissons à fine et large échelles spatiales, étudier l’impact des conditions environnementales et socio-économique sur la diversité et la distribution des communautés de poissons et informer les gestionnaires sur les zones de priorité de conservation<br>Accelerating global changes and human impacts threaten the survival of fish communities worldwide, which are critical to the functioning of marine ecosystems and fisheries-dependent populations. Only an effective and rapid monitoring of fish communities at small and large scales to understand their distributions, assembly rules and impacts of human and environmental pressures can enable the implementation of optimal conservation measures. Environmental DNA (eDNA) is a recent method that has been demonstrated to be effective at local and regional scales for studying coastal fish communities. This method makes it possible to overcome some biases induced by conventional monitoring methods (fishing, diving, cameras). The goal of this thesis is to use eDNA to study fish distributions at various spatial scales in response to environmental, geographic, and socioeconomic factors, and then to feed conservation planning approaches. I first compared frequently used bioinformatics tools for eDNA data analysis, identified the best programs and pipelines, and constructed an optimal pipeline for identifying species contained in a sample, in the case of a complete reference database. However, at a large scale, the genetic reference databases are largely incomplete for the 12S mitochondrial gene we use, and thus do not allow for taxonomic assignment of all eDNA fragments. The other studies in this thesis therefore rely on a method of clustering sequences into molecular taxonomic units (MOTUs). From a large-scale dataset sampled in three oceans (Indian, Pacific, Atlantic), I compared estimates of coral reef fish diversity obtained with eDNA and with visual census data, at the scale of several bioregions. I demonstrated that eDNA estimated a higher diversity of families and MOTUs than visual census, while recovering the known major distribution patterns (longitudinal gradient, isolation of the Caribbean fauna). Then, on a global scale, I investigated the influence of environmental, geographical and socio-economic factors on several alpha and beta diversity indices, using more than 500 eDNA samples collected in 11 regions of the world. The results show a dominant effect of the environment (temperature and productivity) on alpha and beta diversity, but also a decrease of these diversities in areas close to human populations, and in particular in countries depending on marine resources. Finally, at a regional scale in New Caledonia, by combining eDNA with more conventional methods (baited cameras and acoustic echosounder), I estimated and modeled several metrics of fish diversity on deep outer slopes and seamounts, down to 600m depth, which I then integrated into three-dimensional conservation planning. These results indicate high richness, abundance and biomass on shallow and isolated seamounts, as well as on the deep slopes of islands and atolls far from urbanized areas, which should be prioritized in conservation plans. All this thesis work demonstrates the utility of eDNA metabarcoding to study fish distribution at fine and large spatial scales, to study the impact of environmental and socio-economic conditions on the diversity and distribution of fish communities, and to inform managers on priority areas for conservation
APA, Harvard, Vancouver, ISO, and other styles
4

Laurencio, David Edelman. "Environmental correlates to amphibian and reptile diversity in Costa Rica." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1675.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

TONELLI, MATTIA. "Effects of different pastures management on dung beetle communities in a sub-mountainous landscape of central Italy: a multicomponent biodiversity and ecological process analysis." Doctoral thesis, Urbino, 2017. http://hdl.handle.net/11576/2642392.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Aguirre, Andrea Garafulic. "A diversidade da regeneração natural e fatores que podem influenciar o aumento da riqueza regenerante em áreas em processo de restauração com distintas idades /." Rio Claro, 2019. http://hdl.handle.net/11449/183187.

Full text
Abstract:
Orientador: Massanori Takaki<br>Resumo: Grandes iniciativas mundiais no esforço de alavancar um aumento na restauração ecológica surgiram recentemente, como a Iniciativa 20 x 20 e a Bonn Challenge, que apresentam como meta conjunta restaurar 500 milhões de hectares até 2030. Assim, uma das metas da ecologia aplicada à restauração é buscar compreender as distintas maneiras pelas quais a vegetação varia durante o processo de restauração e quais fatores influenciam o aumento da riqueza de espécies regenerantes. Este trabalho teve como objetivos: (1) Compreender como variam a abundância relativa e riqueza rarefeita, quando se comparam a regeneração natural total e específica (espécies que ocorreram apenas na área de referência), nas áreas em restauração com diferentes idades. (2) Avaliar como variam a diversidade alfa e beta nas áreas em restauração com idades distintas. (3) Observar a variação na abertura do dossel nas áreas com idades distintas. (4) Analisar se as variáveis da abertura do dossel e a idade são fatores importantes no que tange à influência com o aumento da riqueza de espécies regenerantes. Nove áreas em processo de restauração, localizadas no município de Extrema (Minas Gerais), foram selecionadas com 4, 7 e 10 anos de idade e um fragmento de referência, onde ao todo, 360 parcelas foram instaladas. Em cada parcela foram mensurados todos os regenerantes entre 20 cm e 2 m de altura (ervas, trepadeiras, arbustos, arbóreas e pteridófitas). Resultados: Foram encontrados 6788 regenerantes. As herbáceas e arb... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Major global initiatives in an effort to leverage an increase in the ecological restoration areas have recently emerged, such as the 20 x 20 Initiative and the Bonn Challenge, which aim to restore together 500 million hectares by 2030. Thus, one of the goals of ecology applied to restoration is to look at the different ways in which vegetation varies during the restoration process and what factors influence the increase of regenerating species richness. This work has as objectives: (1) To understand how the relative abundance and rarefied richness vary, when comparing the total and specific natural regeneration (species that occurred only in the reference area) in restoration areas having varying ages. (2) To evaluate how alpha and beta diversity varies in areas of restoration of different ages. (3) To observe the variation in canopy opening in areas of different ages. (4) To analyze whether the variable canopy opening and age are important factors in the influence or relation with the increase of the richness of regenerating species. Nine areas aged 4,7 and 10 under restoration process were selected and a reference fragment, in which a total of 360 parcels were installed. All the areas are located in the Municipality of Extrema, Minas Gerais. In each plot was measured all regenerants between 20 cm and 2 m in height (herbs, climbers, shrubs, trees and pteridophytes). Results: 6788 regenerants were found. Herbs and trees had the highest relative abundances, general and specifi... (Complete abstract click electronic access below)<br>Doutor
APA, Harvard, Vancouver, ISO, and other styles
7

Deheuvels, Olivier. "Compromis entre productivité et biodiversité sur un gradient d'intensité de gestion de systèmes agroforestiers à base de cacaoyers de Talamanca, Costa Rica." Thesis, Montpellier, SupAgro, 2011. http://www.theses.fr/2011NSAM0026/document.

Full text
Abstract:
Le cacaoyer (Theobroma cacao, L.) est cultivé dans les tropiques humides d'Amérique latine, d'Afrique et d'Asie. Principale source de revenus d'une agriculture essentiellement familiale, les systèmes agroforestiers à base de cacaoyers fournissent de nombreux services écologiques et contribuent à la conservation de la biodiversité. Ces systèmes associent plantes ligneuses et cultures de manière simultanée, dans une gamme importante et peu décrite de richesses et de structures botaniques. Les connaissances actuelles sur leur productivité se limitent à des essais en milieu contrôlé associant un petit nombre d'espèces. Nos travaux testent l'hypothèse d'une relation de compromis entre le niveau de productivité des cacaoyers et le niveau de biodiversité hébergée par les agroforêts à base de cacaoyers. Nous caractérisons ces compromis sur un gradient de situations de production paysannes, reposant sur la structure verticale, l'intensité de gestion de la composante végétale et le contexte bio-physique des agro-systèmes étudiés. Sur un dispositif de 36 cacaoyères paysannes situées dans la région de Talamanca, Costa Rica, nous montrons que des variations significatives de la structure végétale reflètent les modes de gestion de la parcelle et affectent le rendement par cacaoyer (295 à 667g/arbre/an) mais pas le rendement en cacao (136 kg/ha/an), ni le volume végétal global (400 m3/ha). Ces variations de la structure végétale affectent peu la diversité α des peuplements de plantes associées, d'épiphytes, d'amphibiens, de reptiles, de mamifères, d'invertébrés du sol et de la litière, mais leur diversité β répond de manière contrastée à ces variations d'habitat. Les relations de compromis que nous mettons finalement en évidence entre la productivité en cacao marchand à l'hectare ou à l'arbre et les niveaux de biodiversité atteints sont de nature (linéaire, cubique, quadratique) et de tendances (négative, postive) contrastées selon le taxon considéré et remettent en cause les résultats de certains travaux récents. Nos travaux dévoilent également des situations de compromis optimales, offrant des perspectives positives pour l'intensification écologique des systèmes agroforestiers tropicaux<br>Cacao (Theobroma cacao, L.) is cultivated in the humid tropics of Latin America, Africa and Asia. Cocoa-based agroforestry systems are the main source of income for smallholders' families and provide numerous ecological services and contribute to biodiversity conservation. These systems associate trees with crops simultaneously, in a wide and poorly described range of botanical and structural plant diversity. The current knowledge about their productivity is restricted to controlled trials with a low numer of associated plant species. Our work tests the hypothesis of a trade-off relationship between the level of cocoa productivity and the level of biodiversity hosted in cocoa-based agroforests. We characterize these trade-offs on a gradient of production situations, based on the vertical structure, the management intensity of the vegetal component and the bio-physical context of cocoa-based agroforests. On the base of a 36 on farm cocoa plots network located in Talamanca, Costa Rica, we show that significant variations in the vegetation vertical structure reflect farmer's management strategies and affect the cocoa yield per tree (295 to 667g/tree/year) but neither the cocoa yield per plot (136 kg/ha/year), nor the global plant volume (400 m3/ha). The variations in vegetation structure poorly affected the α-diversity of 7 plant and animal taxa, but their β-diversity gave contrasted and significant responses to habitat variations. Finally, the trade-offs relationships we display between dry cocoa productivity per hectare or per tree and the observed biodiversity levels showed contrasted forms (cubic, quadratic, linear) and tendances (positive, negative) according to the taxa considered and question results from recent publications. Our work also revealed optimal trade-off situations which offer positive prospects for the ecological intensification of tropical agroforestry systems
APA, Harvard, Vancouver, ISO, and other styles
8

Labecca, Fábio Martins. "Menos complementares e redundantes, porém mais jovens: organização de assembleias de aves em monoculturas florestais." Universidade Federal de Goiás, 2015. http://repositorio.bc.ufg.br/tede/handle/tede/5068.

Full text
Abstract:
Submitted by Erika Demachki (erikademachki@gmail.com) on 2016-01-07T15:35:40Z No. of bitstreams: 2 Dissertação - Fábio Martins Labecca - 2015.pdf: 2107333 bytes, checksum: cf5e7e0ac514e7f834e6ed7aab735b5d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)<br>Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2016-01-07T15:37:02Z (GMT) No. of bitstreams: 2 Dissertação - Fábio Martins Labecca - 2015.pdf: 2107333 bytes, checksum: cf5e7e0ac514e7f834e6ed7aab735b5d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)<br>Made available in DSpace on 2016-01-07T15:37:02Z (GMT). No. of bitstreams: 2 Dissertação - Fábio Martins Labecca - 2015.pdf: 2107333 bytes, checksum: cf5e7e0ac514e7f834e6ed7aab735b5d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-04-29<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>The increasing demand for timber and pulpwood has triggered an increase in areas of tree monocultures. The effects of native vegetation conversion in such monocultures have been extensively debated, but the consequences of this land use change to functionality and evolutionary history conservation have been little studied. Here, we evaluated how the avifauna responds to nature ecosystem conversion in tree monocultures by quantifying changes in local diversity (alpha diversity) and in assemblage composition (beta diversity), in their functional and phylogenetic components. We compiled forty paired bird lists in native vegetation areas and in comparable tree monoculture areas. Changes in alpha diversity were quantified by paired tests of observed values in native vegetation and in tree monocultures, and changes in assemblages composition through additive partitioning of beta diversity in nestedness and turnover components. We observed that tree monocultures are impoverished in number of species, supporting lower functional richness and less functionally similar assemblages. This demonstrates that environmental filter selecting and limiting similarity processes concurrently modify functional structure of bird assemblages, resulting in loss of functional complementarity and redundancy. Species in tree monocultures are also evolutionary younger and less related to each other. We showed that bird assemblages in tree monoculture are composed largely by functionally and phylogenetic different species from that assemblages in native vegetation. Body size, diet and foraging traits were the major functional traits in predicting the absence of the species in tree monocultures. Alson, we show that annual average temperature, annual average pluviosity and stage of understory development in tree monocultures are important predictors of diversity loss in these type of monoculture.<br>A crescente demanda por madeira e celulose tem desencadeado um aumento das áreas de monocultura florestal. Os efeitos da conversão de áreas de vegetação nativa nesse tipo de monocultura, por sua vez, vêm sendo extensamente debatidos. As consequências dessa mudança no uso do solo para a funcionalidade e conservação da história evolutiva foram até agora pouco estudadas. Neste estudo, nós avaliamos como a avifauna responde a conversão de ecossistemas naturais em monoculturas florestais, quantificando mudanças na diversidade local (diversidade alfa) e na composição dessas assembleias (diversidade beta) em seus componentes funcional e filogenético. Para isto, compilamos quarenta listas pareadas de aves em áreas de vegetação nativa e em áreas comparáveis de monocultura florestal. As mudanças na diversidade alfa foram testadas por testes pareados dos valores observados em vegetação nativa e em monoculturas florestais, e as mudanças na composição das assembleias através da partição aditiva da diversidade beta nos componentes de aninhamento e substituição. Observamos que as áreas de monocultura florestal são empobrecidas no número de espécies, suportam menor riqueza funcional e são menos similares funcionalmente. Isto demonstra que os processos de filtro ambiental e de similaridade limitante modificam a estrutura funcional das assembleias de aves de forma concomitante, resultando em perda de complementaridade e também de redundância funcional. As espécies presentes em áreas de monocultura são também evolutivamente mais jovens e menos aparentadas entre si. Mostramos que as assembleias de monoculturas florestais são compostas em grande parte por espécies funcionalmente e filogeneticamente diferentes daquela avifauna em vegetação nativa. Tamanho corpóreo, dieta e estratégias de forrageamento se mostraram as características funcionais importantes na predição da ausência das espécies em monoculturas florestais. Ainda, mostramos que temperatura e pluviosidade média anual, e o estádio de desenvolvimento do sub-bosque são importantes preditores da perda de diversidade nesse tipo de monocultura.
APA, Harvard, Vancouver, ISO, and other styles
9

Rosset, Véronique, Albert Ruhi, Michael T. Bogan, and Thibault Datry. "Do lentic and lotic communities respond similarly to drying?" WILEY, 2017. http://hdl.handle.net/10150/625362.

Full text
Abstract:
Disturbance is a central factor shaping composition, structure, and dynamics of local communities. Drying is a disturbance that occurs in aquatic ecosystems globally and can strongly influence their communities. Although the effects of drying may depend on ecosystem connectivity and the dispersal abilities of resident species, there have been no comparisons of community responses to drying between lentic and lotic ecosystems across different climates. Here, we predicted that drying would have stronger effects on aquatic communities in isolated lentic ecosystems than in dendritic lotic ecosystems, owing to the higher hydrological connectivity of the latter, and that drying would have stronger effects on passive than on active dispersers, because of the potentially higher recolonizing ability of the latter. We tested these predictions by comparing alpha diversity, phylogenetic relatedness, and beta diversity for active and passive dispersers, in both ecosystem types across five climatic regions. Drying caused greater declines in alpha diversity in lentic than in lotic ecosystems. Communities that experienced drying were more similar to one another than those of perennial sites, and this pattern was especially pronounced in lentic ecosystems. In contrast, drying did not influence the contributions of turnover and richness gradients to beta diversity. Additionally, dispersal mode did not influence community responses to drying. Relatively weaker effects of drying in lotic compared to lentic systems were likely due to the hydrological connectivity among perennial and temporary river sites, which may facilitate dispersal of organisms to escape drying and recolonize rewetted sites. Collectively, our results suggest that habitat connectivity may ameliorate (and fragmentation may worsen) the impacts of drying disturbance. This is an important finding in light of increasing drying and concomitant aquatic habitat fragmentation under global change.
APA, Harvard, Vancouver, ISO, and other styles
10

MARY, JEAN. "Etude de la diversite structurale de l'extremite carboxy-terminale des tubulines alpha et beta." Paris 7, 1996. http://www.theses.fr/1996PA077240.

Full text
Abstract:
Le dimere de tubuline alpha/beta, unite structurale des microtubules, peut-etre tres heterogene. Cette heterogeneite a deux origines: genetique et post-traductionnelle. La region carboxy-terminale de la tubuline concentre la tres grande majorite de cette heterogeneite et serait impliquee dans les interactions entre le microtubule et les proteines qui lui sont associees. Nous avons etudie la tubuline de cerveaux de souris et d'axoneme de spermatozoides d'oursin. La methodologie mise en uvre a fait appel aux techniques de la chimie des proteines. Ce travail a permis de montrer que l'extremite carboxy-terminale de la tubuline alpha detyrosylee etait plus heterogene chez la souris adulte que chez le souriceau. Cette heterogeneite ne serait pas due a une diversification du mode de branchement entre les glutamates ajoutes post-traductionnellement, mais a un accroissement de la proportion de tubuline alpha non tyrosylable. La polyglutamylation a ete caracterisee sur les isotypes de tubuline beta un et quatre a, sur les residus glutamyls en position quatre cent quarante et un et quatre cent trente quatre, respectivement. L'ensemble des isotypes de tubuline beta exprimes dans le cerveau de mammiferes peut donc etre glutamyle. Les differentes modifications post-traductionnelles localisees dans la region carboxy-terminale de la tubuline axonemale de spermatozoides d'oursin et leur importance relative determinee. Dans ce systeme, la majorite des tubulines ne sont pas modifiees dans leur region carboxy-terminale. La tubuline beta peut etre polyglycylee et la tubuline alpha peut etre a la fois polyglutamylee et polyglycylee
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Alpha and beta diversity"

1

Gerard, John. Alpha beta. John Gerard, 2005.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

Steig, Jeanne. Alpha beta chowder. HarperCollins, 1992.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

International Program on Chemical Safety., United Nations Environment Programme, International Labour Organisation, and World Health Organization, eds. Alpha- and beta-hexachlorocyclohexanes. World Health Organization, 1992.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

Rowlands, Betty. Alpha, beta, gamma ... dead. Severn House, 2007.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Kunick, Conrad. Darstellung und Umwandlung [alpha]-substituierter [alpha-substituierter] [beta]-Oxosulfoxide [Beta-Oxosulfoxide]. [s.n.], 1986.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

International Program on Chemical Safety., United Nations Environment Programme, International Labour Organisation, and World Health Organization, eds. Alpha- and beta- hexachloro-cyclohexanes (Alpha- and beta- HCHs) health and safety guide. World Health Organization, 1991.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

Kindermann, Richard. Zum Übergangszustand der Diels-Alder-Reaktionen [alpha],[beta]-ungesättigter [alpha-beta-ungesättigter] Carbonylverbindungen. [s.n.], 1989.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

Spescha, Maurus. Enantioselektive kupferkatalysierte 1,4-Addition von Grignardreagenzien an [alpha],[beta]-ungesättigte [alpha,beta-ungesättigte] Carbonylverbindungen. [s.n.], 1992.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Good, Sharon. Alpha, Beta & Gamma: A small story. Excalibur Pub., 1991.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

Clarke, Roger G. Investing separately in alpha and beta. Research Foundation of CFA Institute, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "Alpha and beta diversity"

1

Perumal, Murali Sankar, and Shreedevasena Sakthibalan. "Downstream Analysis and Visualization-Knowledge Discovery – Alpha and Beta Diversity." In Microbiome-Host Interactions. CRC Press, 2021. http://dx.doi.org/10.1201/9781003037521-4.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Cavender-Bares, Jeannine, Anna K. Schweiger, Jesús N. Pinto-Ledezma, and Jose Eduardo Meireles. "Applying Remote Sensing to Biodiversity Science." In Remote Sensing of Plant Biodiversity. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-33157-3_2.

Full text
Abstract:
AbstractBiodiversity is organized hierarchically from individuals to populations to major lineages in the tree of life. This hierarchical structure has consequences for remote sensing of plant phenotypes and leads to the expectation that more distantly related plants will be more spectrally distinct. Applying remote sensing to understand ecological processes from biodiversity patterns builds on prior efforts that integrate functional and phylogenetic information of organisms with their environmental distributions to discern assembly processes and the rules that govern species distributions. Spectral diversity metrics critical to detecting biodiversity patterns expand on the many metrics for quantifying multiple dimensions of biodiversity—taxonomic, phylogenetic, and functional—and can be applied at local (alpha diversity) to regional (gamma diversity) scales to examine variation among communities (beta diversity). Remote-sensing technologies stand to illuminate the nature of biodiversity-ecosystem function relationships and ecosystem service trade-offs over large spatial extents and to estimate their uncertainties. Such advances will improve our capacity to manage natural resources in the Anthropocene.
APA, Harvard, Vancouver, ISO, and other styles
3

Record, Sydne, Kyla M. Dahlin, Phoebe L. Zarnetske, et al. "Remote Sensing of Geodiversity as a Link to Biodiversity." In Remote Sensing of Plant Biodiversity. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-33157-3_10.

Full text
Abstract:
AbstractTwo common approaches to conserving biodiversity are conserving the actors (species) and conserving the stage (habitat). Many management efforts focus on conserving the actors, but a major challenge to this strategy is uncertainty surrounding how species’ geographic ranges might shift in response to global change, including climate and land use change. The Nature Conservancy has moved to conserving the stage, with the aim of maintaining the processes that generate and support biodiversity. This strategy requires knowing how biodiversity responds to geodiversity—the abiotic features and processes that define the stage. Here we explore how remote sensing illuminates the relationship between biodiversity and geodiversity. We introduce a variety of geodiversity measures and discuss how they can be combined with biodiversity data. We then explore the relationship between biodiversity and geodiversity with tree biodiversity data from the US Forest Inventory and Analysis Program and geodiversity data from the Shuttle Radar Topography Mission as a case study and proof of concept. We find that whereas beta diversity was not well explained by geodiversity, both alpha and gamma diversities were positively related to geodiversity. We also outline the challenges and opportunities of using remote sensing to understand the relationship between biodiversity and geodiversity.
APA, Harvard, Vancouver, ISO, and other styles
4

Callin, Sabrina. "Alpha, Beta, and Alpha-Beta Separation." In Portable Alpha Theory and Practice. John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781119198123.ch5.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Liu, Mark. "Alpha-Beta Pruning." In AlphaGo Simplified. Chapman and Hall/CRC, 2024. http://dx.doi.org/10.1201/9781032722207-6.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Lütjering, Gerd, and James C. Williams. "Alpha + Beta Alloys." In Titanium. Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-540-71398-2_5.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Xia, Yinglin, and Jun Sun. "Alpha Diversity." In Bioinformatic and Statistical Analysis of Microbiome Data. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-21391-5_9.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Glaser, Christian. "Alpha- und Beta-Fehler." In Risiko im Management. Springer Fachmedien Wiesbaden, 2019. http://dx.doi.org/10.1007/978-3-658-25835-1_28.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Lemmer, Boris, Benjamin Bahr, and Rina Piccolo. "Alpha-, Beta- und Gammastrahlen." In Quirky Quarks. Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-50259-4_43.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Parkins, Paul, and John A. Keane. "Alpha-Beta Search Revisited." In Intelligent Data Engineering and Automated Learning — IDEAL 2002. Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-45675-9_88.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Alpha and beta diversity"

1

Hua, Zhengyu, and Yanxin Zhang. "Finding $(\alpha, \beta, k)$-community on birpartite graph." In 2024 3rd International Conference on Cloud Computing, Big Data Application and Software Engineering (CBASE). IEEE, 2024. https://doi.org/10.1109/cbase64041.2024.10824505.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Fay, Alexander, Nathaniel Badgett, Sean Hunt, and Sam Shue. "Ruggedized Composite Alpha and Beta Particle Scintillator Dataset." In SoutheastCon 2025. IEEE, 2025. https://doi.org/10.1109/southeastcon56624.2025.10971606.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Venkatesan, Kishore, David Ritchie, Dimitri Conjan, Sri Lathabai, and Darren Fraser. "Corrosion Studies of an Additive Manufactured Alpha-Beta Ti Alloy." In CORROSION 2021. AMPP, 2021. https://doi.org/10.5006/c2021-16874.

Full text
Abstract:
Abstract α-β titanium alloys are used extensively in various industries, from aerospace to power generation, oil and gas and bio-medical applications. Production of these alloys, in recent years, has been explored using additive manufacturing methods (AM). The effect of process parameters on the electrochemical behavior of α-β titanium alloys produced by Electron Beam Melting (EBM) was studied. The as-built parts were examined using optical and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). SEM examination of samples post electrochemical tests was also performed to understand the corrosion mechanisms and relate them to the microstructures and process parameters. The results from this study are presented in this paper.
APA, Harvard, Vancouver, ISO, and other styles
4

Raut, Roshani, Mayur Chaudhari, Shreya Raipalli, and Sankalp Banginwar. "Enhancing AI Strategy in Checkers through Minimax and Alpha-Beta Pruning Techniques." In 2025 International Conference on Sustainable Energy Technologies and Computational Intelligence (SETCOM). IEEE, 2025. https://doi.org/10.1109/setcom64758.2025.10932634.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Gorbach, A. V., A. P. Mikhalenka, L. I. Kastukevich, O. N. Romanova, and A. V. Kilchevsky. "ASSESSING THE BIODIVERSITY OF THE MICROBIOME OF ENDOSCOPICALLY HEALTHY AND INFLAMMATORY COLONIC MUCOSA IN CHILDREN WITH INFLAMMATORY BOWEL DISEASE." In XI МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ МОЛОДЫХ УЧЕНЫХ: БИОИНФОРМАТИКОВ, БИОТЕХНОЛОГОВ, БИОФИЗИКОВ, ВИРУСОЛОГОВ, МОЛЕКУЛЯРНЫХ БИОЛОГОВ И СПЕЦИАЛИСТОВ ФУНДАМЕНТАЛЬНОЙ МЕДИЦИНЫ. IPC NSU, 2024. https://doi.org/10.25205/978-5-4437-1691-6-230.

Full text
Abstract:
A comparative analysis of the microbial composition in endoscopically healthy (group Control) and inflamed (group Damaged) mucosal areas in children with inflammatory bowel disease was conducted using metataxonomic analysis by 16S rRNA gene fragment sequencing. Differences in the relative abundance of dominant bacterial families were identified. However, statistically significant differences in the alpha and beta diversity of microbial communities weren’t found.
APA, Harvard, Vancouver, ISO, and other styles
6

Quintero, Carolina. "Patterns in gall species diversity across altitudinal and precipitation gradients in northern Patagonia, Argentina: Explanatory variables switch between alpha and beta diversity." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.92668.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Laird, Joshua, and Jonathan M. Adrain. "BETWEEN-HABITAT DISSIMILARITY (BETA-DIVERSITY) RESPONSE OF TRILOBITES TO THE END-ORDOVICIAN MASS EXTINCTION: A MECHANISM TO MAINTAIN WITHIN-HABITAT RICHNESS (ALPHA-DIVERSITY)." In GSA Connects 2023 Meeting in Pittsburgh, Pennsylvania. Geological Society of America, 2023. http://dx.doi.org/10.1130/abs/2023am-394819.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Popović, Filip J., Tanja B. Trakić, Mirjana M. Stojanović, and Jovana M. Sekulić. "Abundance, species richness and diversity of earthworms (lumbricidae) in several habitats of the northern part of Jastrebac Mountain." In 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.280p.

Full text
Abstract:
The aim of this study was to investigate the diversity of earthworms in different habitats (meadow, humid meadow, oak and beech forest). A total of nine earthworm species belonging to six genera were found in the studied habitats. In the studied habitats, the earthworm fauna was found to be different: the beech forest was richer in earthworms (6 taxa), while the oak forest was poorest in earthworms (3 taxa). The earthworm abundance was higher in the humid meadow (34 individuals), while was lower in the beech forest (17 individuals). A combination of the alpha diversity index (Shannon-Weaver, Evenness, and Berger-Parker) and beta diversity (Jaccard’s coefficient of similarity) were used to determine the impact of studied habitats on the earthworm fauna. Shannon’s diversity and Shannon’s evenness indices had higher values in the beech forest/humid meadow, while the Berger-Parker index of dominance had higher values in oak forests. Jaccard’s index of similarity showed the earthworm fauna was clearly separated between the oak forest, meadow, humid meadow and beech forest. The results of these indices confirmed that vegetation cover strongly influences the diversity of earthworm fauna.
APA, Harvard, Vancouver, ISO, and other styles
9

Teles, Ludmila Thommen, Vitor Heidrich, Rosângela Vieira de Andrade, et al. "Enrichment of intestinal bifidobacterium genus is associated with residual disease among patients with early-stage HER2+ breast cancer (BC) following neoadjuvant chemotherapy (NACT)." In Brazilian Breast Cancer Symposium 2024. Mastology, 2024. http://dx.doi.org/10.29289/259453942024v34s1016.

Full text
Abstract:
Objective: The objective of this study was to characterize the gut microbiome (GM) of patients with early-stage breast cancer (eBC) who underwent NACT and to evaluate its association with clinicopathological factors and outcomes. Methodology: This was a prospective study conducted at two Brazilian Institutions. Fecal samples were collected at the baseline and prior to surgery. The GM was analyzed by 16S rRNA amplicon sequencing to characterize the alpha (InvSimpson indexes) and beta (weighted UniFrac distance) diversity, as well as the taxonomic composition. Results: Among the 55 female patients included, the median age was 49 years, 56% had stage III disease, and 23% had used antibiotics in the prior 2 months before starting NACT. Regarding the immunohistochemical profile, 34.5% (n=19) of patients had estrogen receptor-positive (ER+)/HER2-negative BC, 20% (n=11) had HER2-positive disease, and 45.5% (n=25) were triple-negative. All patients with ER+ had KI 67 &gt;14%. There was no significant difference in alpha or beta-diversity between patients with or without pathological complete response, nor within clinical pathologic factors. The taxonomic profiling of fecal samples revealed that Lachnospiraceae at family and Blautia at genus levels were the most abundant taxon, and longitudinal samples collected during NACT showed no significant changes in GM composition. We found an enrichment for Clostridia sp. among patients who did not use antibiotics (p &lt;0.05, pFDR≤0.25). Notably, we found a higher abundance of Bifidobacterium genus (p &lt;0.05, pFDR≤0.25) in baseline samples from patients with HER2+ tumors who presented residual disease following NACT. Conclusion: This pilot study demonstrates the feasibility of GM sequencing in patients with eBC. We identified a significant association between the relative abundance of intestinal Bifidobacterium genus response to NACT among patients with HER2+ tumors. If validated, these results can help tailor the preoperative systemic treatment of patients with HER2+ eBC.
APA, Harvard, Vancouver, ISO, and other styles
10

Lalinska-Volekova, Bronislava, Hana Majerova, Ivona Kautmanova, Tomas Farago, Dana Szaboova, and Jana Brcekova. "MICROBIAL COMPOSITION OF NATURAL Fe OXYHYDROXIDES AND ITS INFLUENCE ON ARSENIC AND ANTIMONY SORPTION." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/5.1/s20.037.

Full text
Abstract:
The presented paper represents a comprehensive analysis of hydrous ferric oxides (HFOs) precipitated from Fe rich drainage waters contaminated by arsenic and antimony. Ochre samples from three abandoned Sb deposits were collected in three different seasons and were characterized from the mineralogical, geochemical, and microbiological point of view. They were formed mainly by poorly crystallized 2-line ferrihydrite, with the content of arsenic in samples ranging from 0.7 wt.% to 13 wt.% and content of antimony ranging from 0.025 wt.% up to 1.2 wt.%. Next-generation sequencing approach with 16S RNA, 18S RNA and ITS markers was used to characterize bacterial, fungal, algal, metazoal and protozoal communities occurring in the HFOs. In the 16S RNA, the analysis dominated bacteria (96.2 %) were mainly Proteobacteria (68.8 %) and Bacteroidetes (10.2 %) and to less extent also Acidobacteria, Actinobacteria, Cyanobacteria, Firmicutes, Nitrosprae and Chloroflexi. Alpha and beta diversity analysis revealed that the bacterial communities of individual sites do not differ significantly, and only subtle seasonal changes were observed. This study provides evidence of diverse microbial communities that exist in drainage waters and are highly important in the process of mobilization or immobilization of the potentially toxic elements.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Alpha and beta diversity"

1

Ratliff, Raymond D. Sierra Nevada meadows: species alpha diversity. U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, 1993. http://dx.doi.org/10.2737/psw-rn-415.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Hendricks, J. S., and R. E. Prael. MCNP S(. alpha. beta. ) detector scheme. Office of Scientific and Technical Information (OSTI), 1990. http://dx.doi.org/10.2172/6027558.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Semiatin, S. L., B. C. Kirby, and G. A. Salishchev. Coarsening Behavior of an Alpha-Beta Titanium Alloy. Defense Technical Information Center, 2004. http://dx.doi.org/10.21236/ada428814.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Berger, Martin J. Counting yields for beta and alpha particle sources. National Institute of Standards and Technology, 2000. http://dx.doi.org/10.6028/nist.ir.6464.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Leyba, J. D. Gross alpha/beta determination by liquid scintillation counting. Office of Scientific and Technical Information (OSTI), 1992. http://dx.doi.org/10.2172/10110637.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Leyba, J. D. Gross alpha/beta determination by liquid scintillation counting. Office of Scientific and Technical Information (OSTI), 1992. http://dx.doi.org/10.2172/6835217.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Gregory, Victoria, Guido Menzio, and David Wiczer. The Alpha Beta Gamma of the Labor Market. Federal Reserve Bank of St. Louis, 2021. http://dx.doi.org/10.20955/wp.2021.003.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Gregory, Victoria, Guido Menzio, and David Wiczer. The Alpha Beta Gamma of the Labor Market. National Bureau of Economic Research, 2021. http://dx.doi.org/10.3386/w28663.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Kamata, Tetsuji. (ALPHA) 2 (BETA) 1 Integrin-Induced Breast Cancer Differentiation. Defense Technical Information Center, 2001. http://dx.doi.org/10.21236/ada398563.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Dignon, J., M. Frank, and N. Cherepy. Remote Sensing of Alpha and Beta Sources - Modeling Summary. Office of Scientific and Technical Information (OSTI), 2005. http://dx.doi.org/10.2172/885413.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Alpha and beta diversity' for particular source types:
Journal articles Dissertations / Theses Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography