Individual variation in plant traits drives species interactions, ecosystem functioning, and responses to global change

Ecologists have long sought to understand the processes that lead to the riotous diversity in communities of organisms that inhabit disparate climates and landscapes. Such a diversity of traits leads to a diversity of interactions among species in natural communities, which in turn generates a diversity of potential responses to ongoing global change. In this dissertation, I do three things: I explore the forces that structure plant communities and the ecosystem functions that they mediate, I describe patterns of variation among communities, species, and individual organisms across environmental contexts, and I disentangle the direct effects of global change from the indirect, cascading effects that result from disruptions of species interactions. I accomplish these goals through the synthesis of global data, the development of statistical and mathematical models, and the manipulation of global change drivers in field experiments. In the first chapter, I present a globe-spanning meta-analysis of plant functional trait patterns along elevational gradients. This meta-analysis shows that the plant traits that drive ecosystem function follow predictable trends with elevation due to climate filtering, and that much of this variation is at the level of the individual organism. In the second chapter, I present simulated data sets and illustrative experimental case studies that quantify how important individual-level variation is for explaining patterns in nature. In the third chapter, I present results from intensive plant sampling across a wide range of mountain environments; even in these harsh environments where only the hardiest species can survive, individual-level variation is so high that it makes predictions based on species identity nearly impossible. The fourth and fifth chapters consist of experimental evidence that ongoing human-caused global change is affecting montane plant communities, that species interactions mediate many of these effects, and that variation in the abiotic environment causes variation in both species interactions and in global change response. I demonstrate this through an experiment that combines nitrogen fertilization with removal of a dominant plant species in a montane meadow, and an experiment replicated at low and high elevations crossing dominant species removal with simulation of global warming

Ecological fate of microplastics in a tropical marine environment

This thesis emphasises the severity of the ecological issue surrounding microplastic pollution. Global trends of bioaccumulation and biomagnification were not observed, yet local assessments show microplastics bioconcentrate in coral reef organisms. Biomagnification is possible, with trophic transfer a prominent pathway of exposure. Microplastics are heterogeneous, variable, and persistent in all matrices in the Great Barrier Reef

An Introduction to Quantum Computing for Non-Physicists

Richard Feynman's observation that quantum mechanical effects could not be simulated efficiently on a computer led to speculation that computation in general could be done more efficiently if it used quantum effects. This speculation appeared justified when Peter Shor described a polynomial time quantum algorithm for factoring integers. In quantum systems, the computational space increases exponentially with the size of the system which enables exponential parallelism. This parallelism could lead to exponentially faster quantum algorithms than possible classically. The catch is that accessing the results, which requires measurement, proves tricky and requires new non-traditional programming techniques. The aim of this paper is to guide computer scientists and other non-physicists through the conceptual and notational barriers that separate quantum computing from conventional computing. We introduce basic principles of quantum mechanics to explain where the power of quantum computers comes from and why it is difficult to harness. We describe quantum cryptography, teleportation, and dense coding. Various approaches to harnessing the power of quantum parallelism are explained, including Shor's algorithm, Grover's algorithm, and Hogg's algorithms. We conclude with a discussion of quantum error correction.Comment: 45 pages. To appear in ACM Computing Surveys. LATEX file. Exposition improved throughout thanks to reviewers' comment

Colour morphological sieves for scale-space image processing

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Habitat Attributes Dictate the Roles of Dispersal and Environmental Filtering on Metacommunity Assembly at Coastal Soft‑Bottom Ecosystems

Tracking the effects of habitat attributes on species distribution is pivotal to the understanding of community assembly across space and time. We used the elements of metacommunity (EMS), which evaluates coherence, turnover, and boundary clumping of species, to access the spatial patterns of nematodes from three coastal habitats with increasing degree to wave exposure, namely, mangroves, estuarine unvegetated tidal flats, and sandy beaches. Each habitat was sampled in four locations, hundreds of kilometers apart from each other. We hypothesized that (1) coastal habitats act as metacommunity boundaries and drive positive turnover and clumped distribution of species and (2) metacommunity structure within coastal habitats depends on the habitats’ degree to wave exposure since wave energy generally decreases sediment heterogeneity and favors connectivity among locations. Habitats were the main drivers of species turnover, with tidal flats harboring a transitional assemblage between mangrove and sandy beach. Metacommunities from the different habitats showed distinct patterns of organization among locations. Mangroves were characterized by species loss, with smaller areas of mangroves harboring a subset of the species pool present on larger areas of mangroves. Tidal flats showed positive species turnover among the different estuaries, with co-occurring species responding as a group to environmental variations. Both patterns indicate environmental filtering as the main driver at these less wave-exposed habitats. At sandy beaches, in contrast, metacommunity displayed a random pattern, suggesting high connectivity among locations. Our study confirmed that habitat attributes may induce distinct mechanisms of metacommunity assembly at coastal soft-bottom ecosystems.publishedVersio

Unit Operations of Particulate Solids

Suitable for practicing engineers and engineers in training, this book covers the most important operations involving particulate solids. Through clear explanations of theoretical principles and practical laboratory exercises, the text provides an understanding of the behavior of powders and pulverized systems. It also helps readers develop skills for operating, optimizing, and innovating particle processing technologies and machinery in order to carry out industrial operations. The author explores common bulk solids processing operations, including milling, agglomeration, fluidization, mixing, and solid-fluid separation

Soil Moisture Estimation for landslide monitoring: A new approach using multi-temporal Synthetic Aperture RADAR data

This study explores the utility of the Spotlight2 X-band Synthetic Aperture Radar product developed by the Italian Space Agency for use in multi-temporal estimation of soil moisture in a landslide monitoring context, using a time series of monthly images of the Hollin Hill Landslide Observatory – North Yorkshire, UK. The study shows the complexity of surface soil moisture at an active landslide, using high resolution in situ soil moisture data. This in situ data is also used for ground truthing the soil moisture estimations from the SAR data. The study shows the limitations of inter-and intra-sensor calibration within the Cosmo-SkyMed array and contextualises this problem within the current research climate where SAR imagery is increasingly being created using multi-satellite constellation, while being used, increasingly, by environmental scientists rather than remote sensing specialists

Utilization of municipal solid waste incinerator fly ash in cement mortars

Disposal of municipal solid waste has become a major problem in many countries around the world. With the benefits of substantial weight and volume reduction and potential energy recovery, incineration has become a promising municipal solid waste (MSW) management option. Despite the fact that incineration reduces volume and mass of the wastes by as much as 80%, there are still residues to be properly managed. This research is aimed at evaluating the potential of different types of MSWI fly ash from an incineration facility to be used in cement mortars by using existing standard test methods for cement and coal fly ash. Two types of MSWI fly ash samples: chemically treated and untreated fly ashes, were used. The treated fly ash was used to replace fine aggregates while the finer untreated fly ash was used to directly replace cement in mortars. Fractionation by air classification was introduced to separate the raw untreated fly ash into fine and coarse fractions to improve usability. MSWI fly ash, in its raw and fractionated forms, has been characterized with a view to utilizing the material to replace part of portland cement in mortars. Characterization involved chemical and physical analyses, observation under Environmental Scanning Electron Microscope (ESEM), and X-ray fluorescence (XRF) and X-ray Diffraction (XRD) analyses. Results showed that both raw and fractionated fly ashes significantly enhanced compressive strengths of mortar specimens. Attempts were also made to specify the sources of the additional strength by microstructural examination as well as XRD analyses of the hydration products of MSWI fly ash cement mortar pastes. A new chemical phase was identified exclusively in the MSWI fly ash-cement paste. High absorption capacity of the fly ashes and the formation of C3A.CaCl2.10H2O were responsible for the superior strength properties. Toxicity Characteristic Leaching Procedure (TCLP) tests were performed on these specimens to assess the likelihood of heavy metals being released into the environment. The benefits of using MSWI fly ash in mortar are twofold; namely, the cost savings stemming from reduction in the cement used, and the ecological advantage of ensuring a final destination for the ash

Application of Acoustics and Optics for the Characterization of Suspended Particulate Matter within an Estuarine Observing System

As part of this dissertation work, a long term observing station at Clay Bank on the York River in Virginia has been established and maintained since 2006, and was used to gain a better understanding of sediment processes in a muddy estuary and in muddy coastal environments in general. While data from this NSF-funded Multi-Disciplinary Benthic Exchange Dynamic (MUDBED) observing system has and will be used by other students for this general purpose, this dissertation focuses specifically on better understanding and interpretation of the data collected by key instrumentation regularly deployed at the observing station, especially the acoustic Doppler velocimeter (ADV). Chapter 1, the introduction to this dissertation, provides an overview of the setting for the MUDBED observing system, namely the York River Estuary, Virginia, and briefly discusses some of the scientific and societal issues that motivate the ongoing study of this environment. Background is provided into the history of the MUDBED observing system and into the properties and operation of the ADV and other key instruments applied in this dissertation, including the Laser In Situ Scattering Transmissometer (LISST) and two particle cameras. In the context of describing these instruments, the science papers associated with the dissertation (Chapters 2 through 6) are introduced. Chapter 2 describes use of SonTek ADVs within the real-time components of the MUDBED observing system and findings based on ADV observations through 2009. ADVs deployed at Clay Bank, and also at a more biologically-dominated down-river site, provided long-term estimates of water velocity, bottom stress, suspended sediment concentration, sediment settling velocity (ws), and bed stress under spatially and seasonally variable conditions. Bed erodibility and ws were found to be inversely correlated in both time and space, but both tended to remain more consistent in time at the biological site. at the physical site the erodibility increased and ws decreased following seasonal increases in river discharge. Chapter 3 reports on dual use of a mixing tank for calibrating SonTek ADV acoustic backscatter (ABS) and for direct Doppler measurement of w s. This study utilized the fact that, absent net vertical volume flux, the average vertical velocity registered by an ADV across a horizontal plane is equal to the sediment\u27s mean ws. A series of calibrations were run for sand sizes between 63 and 150 mum . A grid of ADV measurements revealed that the mean vertical velocity registered by the ADV was indeed consistent with each grain size\u27s ws as independently measured in a settling tube. Also, a systematic increase in the proportionality between sand concentration and ABS was observed with increasing grain size. Chapter 4 compares ABS from five 6-MHz Nortek ADVs versus five 5-MHz SonTek ADVs to examine the relative roles played by inter-vendor, intra-vendor, and sediment variability in determining their ABS response. Significant ABS offsets were found for both vendors\u27 ADVs. Before offset correction, ABS was more consistent among Nortek or SonTek units which had consecutive serial numbers. Sand calibrations indicated that the higher frequency Norteks were more susceptible to attenuation. For well-mixed silty-mud in the lab, calibration slopes for both vendors were close to the theoretical value for a constant grain-size suspension. In the field, however, a clearly different slope suggests a change in the acoustic properties of suspended particles with concentration. Chapter 5 characterizes suspended sediment at Clay Bank in the presence of both muddy flocs and pellets through use of an ADV for bulk ws, pump samples for mass concentration, and a LISST plus a high definition (non-video) particle camera for size distribution. Mass concentration, bulk ws and an abundant ---90 mm size class were found to be in phase with velocity and stress, consistent with the suspension of relatively dense, rapidly settling and resilient pellets. Volume concentration of an abundant ---300 mm class peaked well after stress and velocity began to decrease, consistent with the formation of lower density, slowly settling and fragile flocs. Chapter 6 builds on Chapter 3 by utilizing two separate ADV methods to measure ws and comparing both to observations from settling tubes. as well as direct Doppler measurement of sand, ws for mud was measured by assuming a Rouse balance between upward Reynolds flux and downward settling. Rouse-balance ADV estimates of ws were collected at Clay Bank for muddy flocs and confirmed in situ by a high-definition video settling column. Observations suggested that, in the absence of significant particle aggregation/disaggregation, (i) measurement of ws and (ii) ws itself are both relatively insensitive to the local intensity of fluid turbulence for ws up to several cm/s

An Evaluation of the Lithologies and Geochemistry of the Upper Beaver Deposit of the Kirkland Lake Area

The Upper Beaver Cu-Au deposit contains a unique style of mineralization in the Larder Lake and Kirkland Lake areas in terms of mineralization, alteration style, and age. This study aims to use company-provided data, supplemented with focused data collection, to evaluate what information can be attained from company-provided geochemical data. The evaluation uses a combination of hand sample, petrographic, geochemical, statistical, and microprobe analytical methods. Lithogeochemical analyses indicated that the altered igneous host rock is calc-alkaline in composition and is most likely part of the diorite-monzonite suite. Further, exploratory data analysis of Au and Cu mineralization identified that there are two distinct styles of mineralization in the deposit, including: (1) a Cu-rich style of mineralization and (2) a Mo-rich style. SR-XRF trace element mapping shows that the two styles of mineralization also differ at the microscopic scale