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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Mechanisms of Coexistence Between Two Octopus Species In A South Florida Lagoon

Unknown Date (has links)
Theoretically, sympatric species must partition resources or space to allow for coexistence. Determining empirically the specific resources each species exploits and species’ interactions (e.g., intra- and interspecific competition) can sometimes be challenging, thus the data are relatively sparse for certain taxa. This paucity of data exists for octopuses. Therefore, I chose to study niches of two sympatric octopuses (Octopus vulgaris and Macrotritopus defilippi) in an intracoastal habitat. Specifically, I assessed (1) spatial distribution of octopus home or “den” space, (2) habitat association, (3) octopus abundance, (4) foraging activity periods, (5) diet, and (6) associated substrates and behaviors used during foraging events. Octopus den locations were marked by GPS to quantify spatial patterns of both species and their spatial relationship to each other. Habitat associations were measured by quantifying photoquadrats of den and surrounding habitats. For foraging activity periods, a video camera was placed near an octopus den for 24-h observation to determine when each octopus species leaves/returns from foraging. Underwater video recording was used to determine associated foraging substrates and behaviors for both species. Prey remains from octopus’ dens and video recordings indicating prey consumption were used to determine diets of the two octopus species. Video recordings from the 24-h camera and foraging behavior events also provided observations of intra- and interspecific interactions. Results revealed that the two species are interspersed throughout the shallow Florida lagoon and are both abundant during the spring months (March, April, May). Although both species are interspersed throughout the lagoon, their den and surrounding habitat association differed. O. vulgaris was associated with hard bottom and M. defilippi was associated with soft bottom, thus they may not compete strongly for habitats. Each species used different foraging strategies and different primary prey, which may also lessen competition and facilitate coexistence. O. vulgaris had peak foraging activity during night hours, foraged mostly on hard bottom and mainly consumed bivalves while M. defilippi had peak foraging activity during day hours, foraged mostly on soft bottom and mainly consumed crustaceans. Octopuses also had species-specific foraging behaviors, with O. vulgaris using parachute attack and M. defilippi using flounder swimming and tripod stance. Additional intra- and interspecific interactions were video recorded and included: fishes following octopuses, predation attempts, agonistic encounters, cannibalism, and tactile communication. This study identified ecological and behavioral components that may facilitate coexistence of these sympatric species, provided insight into cephalopod niches and ecology, and provided baseline conservation requirements for sand-dwelling cephalopods, both of which may be using this site as a mating and nursery habitat. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection
12

Self-limitation as an explanation for species' relative abundances and the long-term persistence of rare species

Yenni, Glenda Marie 01 May 2013 (has links)
Much of ecological theory describes species interactions. These interactions often play an important theoretical role in facilitating coexistence. In particular, rarity in ecological communities, though often observed, provides a significant challenge to theoretical and empirical ecologists alike. I use a plant community model to simulate the effect of stronger negative frequency dependence on the long-term persistence of the rare species in a simulated community. This strong self-limitation produces long persistence times for the rare competitor, which otherwise succumb quickly to stochastic extinction. The results suggest that the mechanism causing species to be rare in this case is the same mechanism allowing those species to persist. To determine if ecological communities generally show the theoretical pattern, I estimate the strength of frequency-dependent population dynamics using species abundance data from 90 communities across a broad range of environments and taxonomic groups. In approximately half of the analyzed communities, rare species showed disproportionately strong negative frequency dependence. In particular, a pattern of increasing frequency dependence with decreasing relative abundance was seen in these communities, signaling the importance of this mechanism for rare species specifically. Insight into the special population dynamics of rare species will inform conservation efforts in response to climate change and other disturbance. Further difficulties in the detection of theoretical patterns in ecological data may be a result of the ecological currency used. Though ecologists typically use abundance data to test theories, energy use is another ecological currency that may be more relevant in some cases. In particular when detecting patterns that are a result of species interactions, the currency used should be the one in which those interactions actually operate. I compare the results of using abundance and energy use to detect two processes with well-defined expectations. The first is a description of population dynamics, the above described relationship between relative abundance and self-limitation. The second, compensatory dynamics, is a description of community-level dynamics. I find that the currency used alters the results, and thus the species-level implications. It does not, however, alter the overall pattern that would have theoretical implications. Results in both currencies support the pattern of strong self-limitation for persistent rare species.
13

Beyond Tolerations and Accomodation: Amicable Religious Coexistence in the Late Medieval Balkans

Kupin, Marianne 30 April 2012 (has links)
The common image that is associated with the religious atmosphere of the Middle Ages is paradoxical. On the one hand there is an aura of fervent religious piety, which also fueled religious animosity, most notably in the bloodshed and brutality of the Crusades. This overwhelming conflict makes it hard for anyone to imagine the Middle Ages as an ear in which there could have been cordial or harmonious religious coexistence of any kind. This must be considered. In the Balkans during the Late Medieval/ Early Ottoman Period, there existed a form of religious coexistence unlike anything else in Europe. Amicable religious coexistence, that is the sharing of saints and shrines between different faith groups, existed in the Balkans during this time, and continued well into the Modern period. This paper is a discussion of this occurrence and describes the significant factors, which allowed for amicable religious coexistence to take place. / McAnulty College and Graduate School of Liberal Arts / History / MA / Thesis
14

Biodiversity in Two Parts: Environmental Heterogeneity and the Maintenance of Diversity, and the Prioritization of Diversity

Tucker, Caroline 14 January 2014 (has links)
Questions surrounding the causes and consequences of diversity lie at the centre of community ecology. Understanding the mechanisms by which species diversity is maintained motivates much experimental and theoretical work, but this work often focuses on fluctuation-independent mechanisms. Variability in habitat suitability is ubiquitous through space and time however, and provides another important path through which species diversity can be maintained. As a result, considering environmental variability has value for conservation and management. Finally, differences through space and time in the mechanisms that promote and maintain diversity produce spatially varying patterns of diversity. Spatial variation in different forms of diversity (species (SR), phylogenetic (PD), and functional diversity (FD)) creates difficult decisions about prioritization and reserve locations. This thesis uses experimental, observational, and theoretical methods to explore the causes and consequences of diversity. I show that variation in space and time has important implications for species coexistence and diversity maintenance. In microbial nectar communities, temperature variation through space and time alters the importance of priority effects on community assembly. Using models of warming temperatures in annual plant communities I show that considering temporal partitioning of flowering (a strategy to minimize competition) introduces constraints on phenological shifts: this has implications for phenological monitoring programs. Finally, I show that variability in the timing of fire events in Mediterranean shrublands contributes to coexistence between life forms, suggesting that it should be considered for fire management. In the final two chapters, I focus on conservation prioritization. Comparisons of species richness and evolutionary diversity through space in the Cape Floristic Region of South Africa show that existing reserves protect Proteaceae richness, but fail to capture evolutionary distinct species. More generally, in the final chapter I suggest that SR and PD should be congruent through space when species are of similar ages, regions are depauperate, or ranges are discontinuous.
15

Biodiversity in Two Parts: Environmental Heterogeneity and the Maintenance of Diversity, and the Prioritization of Diversity

Tucker, Caroline 14 January 2014 (has links)
Questions surrounding the causes and consequences of diversity lie at the centre of community ecology. Understanding the mechanisms by which species diversity is maintained motivates much experimental and theoretical work, but this work often focuses on fluctuation-independent mechanisms. Variability in habitat suitability is ubiquitous through space and time however, and provides another important path through which species diversity can be maintained. As a result, considering environmental variability has value for conservation and management. Finally, differences through space and time in the mechanisms that promote and maintain diversity produce spatially varying patterns of diversity. Spatial variation in different forms of diversity (species (SR), phylogenetic (PD), and functional diversity (FD)) creates difficult decisions about prioritization and reserve locations. This thesis uses experimental, observational, and theoretical methods to explore the causes and consequences of diversity. I show that variation in space and time has important implications for species coexistence and diversity maintenance. In microbial nectar communities, temperature variation through space and time alters the importance of priority effects on community assembly. Using models of warming temperatures in annual plant communities I show that considering temporal partitioning of flowering (a strategy to minimize competition) introduces constraints on phenological shifts: this has implications for phenological monitoring programs. Finally, I show that variability in the timing of fire events in Mediterranean shrublands contributes to coexistence between life forms, suggesting that it should be considered for fire management. In the final two chapters, I focus on conservation prioritization. Comparisons of species richness and evolutionary diversity through space in the Cape Floristic Region of South Africa show that existing reserves protect Proteaceae richness, but fail to capture evolutionary distinct species. More generally, in the final chapter I suggest that SR and PD should be congruent through space when species are of similar ages, regions are depauperate, or ranges are discontinuous.
16

Human-Lion Territory : Negotiating Territorial Borders

Gibrand, Sara January 2018 (has links)
This thesis explores the interaction between natural and urban life through mutual recognition, viewing the clash of territorial borders as dynamic conditions rather than exclusion zones. Gir area in India has been investigated as a unique case where humans and lions for centuries have lived together and established a mutual respect. Rasulpara village is used as a local situation to analyze the relationship between humans and animals with the intention to understand how such relationship can be maintained. It has led to the recognition of the in-between as intermediate zones mediating exchange between the two systems. With humans relating to settled form as territorial constrains, the language of architecture becomes a messenger of a respect playing with a time-based system; mediating the balance between safe and unsafe. Learning from the existing relationship of mutual understanding aims to extract lessons for how to intervene in the context and other mediation areas between human and wild. Exploring these attributes through design has shown that built form can act as solid borders to classify and preclude, but also to invite cohabitation by respecting means of existence. Territorial conflicts can then be dealt with more sensitively, thus obtaining the equilibrium within a changing world anchored in traditional knowledge.
17

The Coexistence Approach-Theoretical Background and Practical Considerations of Using Plant Fossils for Climate Quantification

Utescher, T., Bruch, A. A., Erdei, B., Franҫois, L., Ivanov, D., Jacques, F. M.B., Kern, A. K., Liu, Y. S.C., Mosbrugger, V., Spicer, R. A. 05 September 2014 (has links)
The Coexistence Approach was established by Mosbrugger and Utescher (1997) as a plant-based method to reconstruct palaeoclimate by considering recent climatic distribution ranges of the nearest living relatives of each fossil taxon. During its existence for over more than 15. years, its basics have been tested and reviewed in comparison with other terrestrial and marine climate reconstruction techniques and climate modelling data. However, some controversies remain about its underlying data or its applicability in general.In view of these controversies this paper discusses the power and limitations of the Coexistence Approach by summarising past results and new developments. We give insights into the details and problems of each step of the application from the assignment of the fossil plant to the most suitable nearest living relative, the crucial consideration of the usefulness of specific taxa towards their climatic values and the correct interpretation of the software-based suggested palaeoclimatic intervals. Furthermore, we reflect on the fundamental data integrated in the Coexistence Approach by explaining different concepts and usages of plant distribution information and the advantages and disadvantages of modern climatic maps. Additionally, we elaborate on the importance of continually updating the information incorporated in the database due to new findings in e.g., (palaeo-)botany, meteorology and computer technology.Finally, for a transparent and appropriate use, we give certain guidelines for future applications and emphasize to users how to carefully consider and discuss their results. We show the Coexistence Approach to be an adaptive method capable of yielding palaeoclimatic and palaeoenvironmental information through time and space.
18

Interactions Among Coexisting Larval Odonata: An in Situ Experiment Using Small Enclosures

Benke, Arthur C., Crowley, Philip H., Johnson, Dan M. 01 September 1982 (has links)
Field experiments using small replicated enclosures focused on interactions between larval populations of Epitheca cynosura and Ladona deplanata (Odonata: Anisoptera) - two species that emerge in early spring. The presence of Epitheca reduced the total biomass of Ladona, but Ladona had no significant effect on Epitheca. These early-emerging species reduced the biomass of small instars of late-emerging Anisoptera which colonized enclosures during the experiments; and the late-emerging Anisoptera seem to have inhibited colonization by Zygoptera larvae. Results are consistent with the importance of predatory (cannibalism or mutual predation) interactions in this community.
19

Ett elevperspektiv på sex- och samlevnadsundervisning i grundskolan : En retrospektiv enkätstudie bland gymnasielever / Students' perspective on sexual and coexistence education in Primary School : A retrospective survey among high school students

Santaoja, Kaj January 2011 (has links)
Public health is a concern of many important areas of society and it is therefore of great importance to examine and expand the goals of public health work within different sectors, e.g., school. Sexually transmitted diseases, sexual violence and mental health problems related to sexual orientation are some of the public health problems in society today. Throughout childhood and teenage years, norms and attitudes regarding sexuality and coexistence are formed, which means that school is an important arena when it comes to creating proficient conditions for    coexistence and sexual health. The quality of sex and coexistence education in Swedish schools differs in quality; for content and magnitude vary greatly among schools. It is, therefore, of interest to study how students experience sex and coexistence education, like prioritizations and desires. The purpose of this study is to describe how high school students experience sex and coexistence education in primary school, and which parts the students consider significant affecting coexistence and sexual health. A quantitative survey (n=113) was conducted at a high school in northeast Skåne. The survey consisted of ten standardized questions regarding experiences and magnitude of sex-and coexistence education in primary school. The results showed that 58,3 percent of the students were dissatisfied with the teaching, and the students prioritized aspects of sexuality and coexistence were included to a lesser extent than the content that was included in the sex- and coexistence education. The teachings in school focused primarily on biological aspects whilst the students prioritized aspects of coexistence. The participants did not consider the school as the main source of information about sex and coexistence. Instead, the students considered friends and family as the primary sources. To decrease the difference between the school and students approach to sex-and coexistence education, an collaboration with external resources should be established. A regional collaboration with affiliates that work with teaching sex and coexistence, like RFSU, could be established in order to gain a larger and abundant content that satisfies the needs of the students. / Folkhälsa berör många samhällsområden och därför är det av vikt att granska och vidareutveckla mål som kan förbättra folkhälsoarbete inom olika sektorer, bland annat skolan. Könssjukdomar, sexuellt våld och psykisk ohälsa relaterat till sexualitet är några av de folkhälsoproblem som finns i dagens samhälle. Under barn- och ungdomstiden utvecklas normer och attityder, kring bland annat sexualitet och samlevnad, vilket innebär att skolan utgör en viktig arena för att skapa goda förutsättningar för samlevnad samt sexuell hälsa. Sex- och samlevnadsundervisningen som bedrivs i de svenska skolorna är av skiftande kvalitet då innehåll och omfattning varierar från skola till skola. Det är därmed av intresse att undersöka hur eleverna upplever undervisningen, såsom aspekter av prioritering och önskningar. Syftet med studien är att beskriva gymnasieelevers upplevelser av sex- och samlevnadsundervisning i grundskolan samt vilka delar av undervisningen som ungdomarna anser är betydelsefulla för den sexuella och sociala hälsan. En kvantitativ enkätundersökning (n=113) genomfördes på en gymnasieskola i nordöstra Skåne. Enkäten innehöll tio standardiserade frågor med fokus på upplevelser och omfattning av sex- och samlevnadsundervisning i grundskolan. Resultatet visade att 58,3 procent av eleverna var missnöjda med undervisningen samt att elevernas prioriterade ämnesområden behandlades i mindre omfattning än de ämnesområden som berördes i sex- och samlevnadsundervisningen. Undervisningen i skolan fokuserade främst på biologiska aspekter medan majoriteten av eleverna prioriterade ämnesområden tillhörande samlevnad. Eleverna ansåg inte heller att skolan var den främsta informationsgivaren av sex och samlevnad, utan vänner och familj ansågs vara de främsta källorna. För att minska klyftan mellan skolans respektive elevernas förhållningssätt till sex- och samlevnadsundervisning borde skolan samarbeta med externa aktörer. Ett rikstäckande samarbete med aktörer inom sex- och samlevnadsupplysning, såsom RFSU, skulle kunna skapa ett bredare och rikare innehåll som tillfredsställer elevernas behov.
20

Technical considerations for co-locating UWB and GPS radios

Van Slyke, Tyler H. January 1900 (has links)
Master of Science / Department of Electrical and Computer Engineering / William B. Kuhn / Excitement about using ultra-wideband (UWB) technology for networking has grown considerably over the last few years. UWB has several strengths, including high data rates, security, and robustness in multipath environments. Despite these benefits, UWB has been scrutinized for its potential to interfere with narrowband technologies like the Global Positioning System (GPS). Until recently, much of the literature about UWB and GPS compatibility has been published on the basis of theoretical analysis alone. We have investigated the compatibility of UWB and GPS signals using theoretical analysis as well as laboratory measurements with a consumer GPS receiver and a WiMedia UWB device. We conclude from our tests that the UWB device does emit interference in the GPS L1 band, but the interference is low enough that careful antenna and chipset placement could allow UWB and GPS radios to coexist in a single product. Also, we have evaluated several UWB antennas to determine their fitness for use in a handheld electronic product. We find that the antennas’ gain pattern and return loss do not have a significant effect upon the data throughput of the UWB system. Thus, we infer that the indoor environment is highly dispersive and that the UWB system is able to exploit multipath propagation. Furthermore, we have created a link budget to estimate the distances over which a WiMedia UWB system should be capable of operating. In the lab, the maximum distances over which the UWB device actually operated were about half of what we expected. This suggests that the path loss exponent and standard deviation of fading could be higher than we expected or that the implementation loss of the UWB chipset is quite high. Currently the market potential of UWB is uncertain. If UWB is embraced by the consumer electronics industry as the wireless platform of choice for Certified Wireless USB and high-speed Bluetooth technology, it could become a ubiquitous networking feature for electronic products such as phones, laptops, cameras, media players, and portable navigation devices. In this thesis, we strive to provide information that would be useful when undertaking a GPS and UWB radio integration project.

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