4,403 research outputs found

    Water Quality and Algal Bloom Sensing from Multiple Imaging Platforms

    Get PDF
    Harmful cyanobacteria blooms have been increasing in frequency throughout the world resulting in a greater need for water quality monitoring. Traditional methods of monitoring water quality, such as point sampling, are often resource expensive and time consuming in comparison to remote sensing approaches, however the spatial resolution of established water remote sensing satellites is often too coarse (300 m) to resolve smaller inland waterbodies. The fine scale spatial resolution and improved radiometric sensitivity of Landsat satellites (30 m) can resolve these smaller waterbodies, enabling their capability for cyanobacteria bloom monitoring. In this work, the utility of Landsat to retrieve concentrations of two cyanobacteria bloom pigments, chlorophyll-a and phycocyanin, is assessed. Concentrations of these pigments are retrieved using a spectral Look-Up-Table (LUT) matching process, where an exploration of the effects of LUT design on retrieval accuracy is performed. Potential augmentations to the spectral sampling of Landsat are also tested to determine how it can be improved for waterbody constituent concentration retrieval. Applying the LUT matching process to Landsat 8 imagery determined that concentrations of chlorophyll-a, total suspended solids, and color dissolved organic matter were retrieved with a satisfactory accuracy through appropriate choice of atmospheric compensation and LUT design, in agreement with previously reported implementations of the LUT matching process. Phycocyanin proved to be a greater challenge to this process due to its weak effect on waterbody spectrum, the lack of Landsat spectral sampling over its predominant spectral feature, and error from atmospheric compensation. From testing potential enhancements to Landsat spectral sampling, we determine that additional spectral sampling in the yellow and red edge regions of the visible/near-infrared (VNIR) spectrum can lead to improved concentration retrievals. This performance further improves when sampling is added to both regions, and when Landsat is transitioned to a VNIR imaging spectrometer, though this is dependent on band position and spacing. These results imply that Landsat can be used to monitor cyanobacteria blooms through retrieval of chlorophyll-a, and this retrieval performance can be improved in future Landsat systems, even with minor changes to spectral sampling. This includes improvement in retrieval of phycocyanin when implementing a VNIR imaging spectrometer

    Doctor of Philosophy

    Get PDF
    dissertationThe objective of this study was to investigate the contribution of multiple demographic and religiosity variables as predictors of ambivalent sexism toward women in a sample of LDS adults. A nationwide sample of 3563 active or former LDS participants were recruited through online social media sites and email. The research design was correlational and used survey instruments. The main findings demonstrated that gender was significantly related to the endorsement of sexism. Overall, men had greater benevolent and hostilely sexist attitudes than women. Gender also moderated the relationship between religiosity and benevolent sexism when LDS activity and affiliation were predictors, such that men's endorsement of sexism increased at a greater rate than women's. Conversely, gender moderated the relationship between all religiosity measures and hostile sexism, such that as religiosity increased, women's endorsement of hostilely sexist attitudes increased more than men's did

    Diet and Reproductive Biology of the Blacknose Shark (Carcharhinus Acronotus) from the Southwestern Atlantic Ocean

    Get PDF
    The blacknose shark (Carcharhinus acronotus) is a common small coastal shark species found in nearshore waters along the southeast coast of the United States, from North Carolina into the Gulf of Mexico and extending further south into the Bahamas. There has been some debate in recent years over the reproductive periodicity of C. acronotus in waters off the U.S. coast. Earlier studies have suggested that Gulf C. acronotus reproduce on an annual basis whereas the Atlantic populations of this species may reproduce biennially. Additionally, there have been no known studies on the diet of C. acronotus. The goal of the present study was to re-evaluate the reproductive biology of the Atlantic populations of C. acronotus with the intent on clarifying discrepancies in reproduction as well as provide information on dietary trends. This was accomplished by examining male and female reproductive tracts and gut contents in animals caught throughout the Atlantic range of C. acronotus. Based on these data, spermatogenesis occurs between late May to early July with peak sperm production occurring in June and July. In females, follicular development is complete by late June-early July with ovulation occurring shortly afterwards. Mating occurs between mid-June and early July based on the presence of fresh mating scars on females captured during this time. Current data suggests that gestation begins late July with parturition occurring late May to early June the following year. As observed in earlier studies, reproductive periodicity appears to be largely biennial. However, evidence for concurrent follicular development and pregnancy was observed in several females, suggesting that at least a portion of the Atlantic population may reproduce on an annual basis. Dietary data shows a dominance of teleost prey items in the diets of C. acronotus with scianids making up the majority of the identifiable teleosts

    Glint Correction of Unmanned Aerial System Imagery

    Get PDF
    Glint in aquatic imagery captured by Unmanned Aerial Systems (UAS) is a limiting factor when performing spectral analysis. It cannot be corrected by methods developed for space-based imaging systems, meaning new approaches are required. Two processes using in-situ radiometric data were developed augmenting an established method for removing atmospheric effects from imagery, the Empirical Line Method (ELM), to remove glint from multispectral UAS imagery. The results of this correction showed good agreement with in-situ spectroradiometer measurements and similar accuracy to atmospherically compensated satellite measurements. The Root-Mean-Square Error of the UAS retrieved remote sensing reflectance was as low as 0.0004 sr -1 and outperformed the traditional ELM

    Determining improvements in Landsat spectral sampling for inland water quality monitoring

    Get PDF
    Inland waters are optically complex and provide an ongoing challenge to effective water quality monitoring through remote sensing. Imaging satellites with spectral sampling designed for this task often have coarse spatial resolutions, preventing any capture of information from small lakes. Medium resolution satellite systems such as Landsat 8 have the appropriate spatial resolution and sensitivity required to resolve these waterbodies, but the spectral sampling is not optimal. This work uses system simulation to explore potential changes to Landsat spectral sampling to determine if its ability to monitor inland waters could be improved. The HydroLight and MODTRAN radiative transfer models are used for simulation in a Look Up Table and spectrum matching approach to provide maximum flexibility intesting spectral sampling scenarios. To isolate the testing to the impacts of spectral sampling, all simulations were performed based on the known system noise characteristics of Landsat 8. Spectral sampling changes tested include the addition of yellow and red edge spectral bands as well as conversion to an imaging spectrometer. Simulated spectra of inland waters undergoing a cyanobacteria bloom, including atmospheric effects and sensor noise, were implemented with the Look-Up-Table retrieval process to extract estimated concentrations of waterbody components. The retrieval accuracy of each potential system is compared to that of a modeled Landsat 8 baseline. All potential systems show an increase of retrieval accuracy over the baseline. The best performing system design is an imaging spectrometer, followed by the addition of both a yellow and red edge band simultaneously, and the addition of either band individually. Testing also demonstrates that resampling an imaging spectrometer with 20 nm spectral resolution to the Landsat 8 band responses produces outputs matching those available from Landsat 8. Our results indicate that future Landsat missions should aim to add as much spectral sampling as is feasible, while maintaining at least the same sensitivity. The minimum change to improve water quality monitoring capability is the addition of a red edge spectral band

    Re-Imagining the Business Trust as a Sustainable Business Form

    Get PDF
    An important policy debate has emerged in the United States concerning how business should evolve to encapsulate more fully the burgeoning sustainability-conscious management paradigm. At issue in this debate is the proper role of business in society. The modern trend in business is to consider more than just shareholder profits. In the United States, companies are increasingly incorporating sustainability practices into their business models. However, by practice and by law, the traditional corporate management paradigm—the shareholder primacy model—holds that the singular social responsibility of business is to maximize shareholder interests, principally shareholder profits. This model conflicts with the sustainability management paradigm, which reflects the view that business should maximize value for society. Some states have realized the shortcomings of the traditional corporate management model and have enacted constituency statutes or created new corporate forms to account for the growth in sustainable corporate practices. However, these statutes and corporate forms have their own shortcomings. Historically, business trusts have been used to circumvent overly-restrictive corporate organizational and legal limitations. Entrepreneurs should once again look to this business form to pursue sustainable practices while maintaining profitability. Due to business trusts’ structure and flexibility, they are an ideal vehicle for sustainable businesses. Accordingly, by drawing upon trust law and corporate law, this Article articulates an interdisciplinary, systematic application of business trusts as an alternative organizational form to corporations for the socially-conscious business management construct
    • …
    corecore