570 research outputs found

    Evaluation of the Basis and Effectiveness of Habitat Assessments in Wetland Functional Assessment Methods

    Get PDF
    I studied the basis and effectiveness of wetland assessment methods in providing habitat assessments. While it is well understood that wetlands and riparian areas provide important ecological functions and habitat for a wide variety of wildlife species, much is still to be learned about providing meaningful, accurate and repeatable methods for assessing them. I examined and evaluated four assessment methods to determine their accuracy and usefulness in assessing a site\u27s provision of habitat. One hypothesis I tested is that if the assessment methods studied provide an accurate assessment of wetland functions, then the resulting site scores for the methods should be correlated. The second hypothesis is that there is a correlation between the site scores and an independent measure of function, specifically the number of riparian-associated bird and butterfly species observed at each site. Biological and physical data collected from 47 riparian sites in California\u27s Central Valley were used to calculate site scores using Habitat Assessment Technique (HAT), Rocky Mountain Riparian Hydrogeomorphic (HGM), Southern California Riparian Model, and Reference Wetland assessment methods. The rankings of these site scores were also calculated for each method. Correlation coefficients (r) were calculated between the site scores of the four methods, as well as between the site scores and the numbers of riparian-associated bird and butterfly species for each plot. The site scores were mostly uncorrelated. Only one statistically significant correlation was demonstrated between the site scores for the Southern California Riparian Model and Reference Wetland methods (df = 46, r = 0.46, p = 0.00103, with Bonferroni correction). With Bonferroni corrections (p \u3c 0.00625), the site scores were also uncorrelated with the numbers of riparian-associated bird and butterfly species. Without Bonferroni corrections, only two statistically significant correlations were demonstrated: between the number of riparian-associated bird species and the HAT score (df = 46, r = 0.37, p = 0.0095) and the number of riparian-associated butterfly species and the Reference Wetland score (df = 46, r = 0.38, p = 0.0092). I rejected both original hypotheses, which demonstrated that the assessment tools currently available do not consistently produce relatively precise, or reproducible results. Possible reasons for these problems include attempting to assess a function that is too broadly defined, inappropriately or subjectively selected variables, subjectively assigning values to variables, or inappropriately selecting reference sites. The existing attempts at assessing wetland or riparian function are important steps in the right direction toward assessment of wetland and riparian sites and achievement of no net loss, but functional assessment must be considered a work in progress

    A Bernstein TypeLpInequality for a Certain Class of Polynomials

    Get PDF
    AbstractBernstein's classical theorem states that for a polynomialPof degree at mostn, max|z|=1|P′(z)|≤nmax|z|=1|P(z)|. We give related results for polynomialsPsatisfying the conditionsP′(0)=P″(0)=···=P(m−1)(0)=0 andP(z)≠0 for |z|<K, whereK≥1. We giveLpinequalities valid for 0≤p≤∞

    Evaluation of Activated Carbon as a Reactive Cap Sorbent for Sequestration of PCBs in Presence of Humic Acid

    Get PDF
    This study investigated the interferences caused by high humic acid concentrations on the adsorption of coplanar and noncoplanar polychlorinated biphenyls (PCBs) on coconut shell activated carbon. In particular, the research focuses on the application of activated carbon as a reactive cap for contaminated sediment sites, a possible intervention to reduce contaminant flux through pore water, and to organisms in aquatic environments. Kinetic and equilibrium studies were conducted using activated carbon as a sorbent for individual PCB congeners including BZ 1, 52, 77, 153, and 169, respectively, in the presence and absence of humic acid. Results showed that preloading of activated carbon with humic acid significantly reduced the adsorption affinity for all selected PCB congeners. Experiments conducted without preloading of activated carbon demonstrated that desorption upon subsequent spiking with humic acid (simulating long-term exposure to pore water that contains high humic acid concentrations) was not found to be statistically significant, and varied with coplanarity of PCBs. Results provide important information for the design of reactive caps in sediments where high concentrations of dissolved organic carbon are found, and highlight the importance of considering site conditions when designing effective reactive caps

    Effect of Humic Acid on Adsorption of Polychlorinated Biphenyls onto Organoclay

    Get PDF
    Mitigation of risks stemming from contaminated sediments in freshwater and estuarine environments remains an important challenge to the field of environmental science and engineering. Capping sediments with reactive materials is one approach that has recently been the subject of research and development. This research evaluated the use of organoclay as a sorbent in a reactive cap for in situ remediation of contaminated sediments, and provides an original contribution by presenting the sorption characteristics of individual polychlorinated biphenyls (PCB) congeners in the presence of high concentrations of humic acids typical of sediment porewater environments. Sorption of coplanar and noncoplanar PCBs on three commercially available organoclays was studied in this work. Studies were conducted to evaluate the kinetics of adsorption of PCBs on organoclay and to determine the effect of humic acid on the kinetics of adsorption. Isotherm studies were conducted to determine the adsorption affinity of PCBs for organoclays in the presence and absence of humic acid. Studies showed a 45 to 96% reduction in the sorption affinity for organoclays after preloading with high concentrations of humic acid, depending both on the congener and the composition of organoclay. Desorption of PCBs upon addition of humic acid after PCBs were equilibrated with organoclay was statistically significant, although the magnitude of the effect was much smaller than that observed from preloading of humic acid

    Putting in your time : Faculty Experiences in the Process of Promotion to Professor

    Get PDF
    The rank of professor or “full” professor represents the highest status possible for faculty members, and it is generally gained by attaining professional expertise and a national or international reputation. Beyond this, however, little is known about these individuals or the promotion process at this level. In this qualitative study of 10 faculty members at one research university in the United States, we sought to understand the experiences of individuals who had sought promotion to full professor. Through a socialization lens, we found that issues of time, a lack of clarity, and gender disparity were concerns for these faculty members

    Faculty Agency in Applying for Promotion to Professor

    Get PDF
    Aim/Purpose: In the United States, faculty who wish to pursue promotion to the rank of professor do so without clear guidance or structure. Even the timing of such a process is nebulous. As such, an individual engages in magentic action to pursue the rank. Background: This study examined the experiences of faculty members who chose to pursue the application process to be promoted to professor but were rejected or dissuaded. Methodology: Utilizing a case study of one institutional setting, we conducted 10 in-depth qualitative interviews. Contribution: Very little is known about the process of promotion to full professor in the U.S. and even less empirical research exists. This study advances knowledge of the process and the experiences of those undertaking it. Findings: We learned that cues from the social context greatly influenced these faculty members’ sense of agency. Keywords: promotion, faculty rank, agenc

    Call for Change

    Get PDF
    Video of University of Maine researchers Amy Blackstone, Susan Gardner and Judith Rosenbaum participate in a roundtable discussion about sexual harassment, equitable workplace environments and #MeToo and #TimesUp

    Structural and dielectric studies of the phase behaviour of the topological ferroelectric La1-xNdxTaO4

    Get PDF
    We thank the University of St Andrews and EPSRC (via DTG studentships to CALD and JG) for funding,The layered perovskite LaTaO4 has been prepared in its polar orthorhombic polymorphic form at ambient temperature. Although no structural phase transition is observed in the temperature interval 25° C < T < 500 °C, a very large axial thermal contraction effect is seen, which can be ascribed to an anomalous buckling of the perovskite octahedral layer. The non-polar monoclinic polymorph can be stabilised at ambient temperature by Nd-doping. A composition La0.90Nd0.10TaO4 shows a first-order monoclinic-orthorhombic (non-polar to polar) transition in the region 250° C < T < 350 °C. Dielectric responses are observed at both the above structural events but, despite the ‘topological ferroelectric’ nature of orthorhombic LaTaO4, we have not succeeded in obtaining ferroelectric P–E hysteresis behaviour. Structural relationships in the wider family of AnBnX3n+2 layered perovskites are discussed.Publisher PDFPeer reviewe
    • …
    corecore