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Numerical solutions and bifurcation analysis of the Fucik spectrum
Get PDFWe use a specialized Newton's method to approximate the Fucik spectrum solution curves of the negative Laplacian on a real Hilbert space. We include results for the two parameter differential equation. After computing the spectrum, we add a nonlinear term and compute bifurcation surfaces
The counselor educator social justice attitudes instrument: An exploratory process assessing dimensionality
Get PDFDespite multiple calls for social justice in counselor education in the past four decades, the frequency of social justice practices in counselor education remains unclear. In order to better understand social justice practices among counselor educators, it is useful to first understand counselor educator attitudes towards social justice. This manuscript presents the construction of the Counselor Educator Social Justice Attitudes Instrument, an instrument measuring counselor educator attitudes towards social justice. In this manuscript, we outline the rationale for the instrument, the development of the instrument, and a critical assessment of the instrument. The final 24-item instrument measuring counselor educator attitudes towards social justice is included. The final instrument is based on three factors accounting for 68.29% variance
Vascular flora of West Clear Creek Wilderness, Coconino and Yavapai Counties, Arizona
Get PDFWest Clear Creek Wilderness bisects the Mogollon Rim in Arizona, and is nested between the Colorado Plateau and Basin and Range physiographic provinces. Between 2013 and 2016, a floristic inventory vouchered 542 taxa and reviewed 428 previous collections to produce a total plant inventory of 594 taxa from 93 families and 332 genera. The most species rich families were Asteraceae, Poaceae, Fabaceae, Brassicaceae, Rosaceae, Plantaginaceae, Cyperaceae, and Polygonaceae. Carex, Erigeron, Bromus, Muhlenbergia, and Oenothera were the most represented genera. Nonnative taxa accounted for seven percent of the total flora. Stachys albens was vouchered as a new state record for Arizona. New county records include Graptopetalum rusbyi (Coconino), Pseudognaphalium pringlei (Coconino), Phaseolus pedicellatus var.grayanus (Coconino), and Quercus rugosa (Coconino and Yavapai). This study quantified and contrasted native species diversity in canyon versus non-‐canyon floras across the Southwest. Analyses based on eighteen floras indicate that those centered about a major canyon feature show greater diversity than non-‐canyon floras. Regression models revealed that presence of a canyon was a better predictor of similarity between floras than was the distance between them.
This study documents the remarkable diversity found within canyon systems and the critical, yet varied, habitat they provide in the southwestern U.S
Tracing melioidosis back to the source: using whole-genome sequencing to investigate an outbreak originating from a contaminated domestic water supply
Get PDFMelioidosis, a disease of public health importance in Southeast Asia and northern Australia, is caused by the Gram-negative soil bacillus Burkholderia pseudomallei. Melioidosis is typically acquired through environmental exposure, and case clusters are rare, even in regions where the disease is endemic. B. pseudomallei is classed as a tier 1 select agent by the Centers for Disease Control and Prevention; from a biodefense perspective, source attribution is vital in an outbreak scenario to rule out a deliberate release. Two cases of melioidosis within a 3-month period at a residence in rural northern Australia prompted an investigation to determine the source of exposure. B. pseudomallei isolates from the property's groundwater supply matched the multilocus sequence type of the clinical isolates. Whole-genome sequencing confirmed the water supply as the probable source of infection in both cases, with the clinical isolates differing from the likely infecting environmental strain by just one single nucleotide polymorphism (SNP) each. For the first time, we report a phylogenetic analysis of genomewide insertion/deletion (indel) data, an approach conventionally viewed as problematic due to high mutation rates and homoplasy. Our whole-genome indel analysis was concordant with the SNP phylogeny, and these two combined data sets provided greater resolution and a better fit with our epidemiological chronology of events. Collectively, this investigation represents a highly accurate account of source attribution in a melioidosis outbreak and gives further insight into a frequently overlooked reservoir of B. pseudomallei. Our methods and findings have important implications for outbreak source tracing of this bacterium and other highly recombinogenic pathogens
Whole-genome sequencing of Burkholderia pseudomallei isolates from an unusual melioidosis case identifies a polyclonal infection with the same multilocus sequence type
Get PDFTwelve Burkholderia pseudomallei isolates collected over a 32-month period from a patient with chronic melioidosis demonstrated identical multilocus sequence types (STs). However, whole-genome sequencing suggests a polyclonal infection. This study is the first to report a mixed infection with the same ST
Leaf-litter leachate is distinct in optical properties and bioavailability to stream heterotrophs
Get PDFDissolved organic C (DOC) leached from leaf litter contributes to the C pool of stream ecosystems and affects C cycling in streams. We studied how differences in leaf-litter chemistry affect the optical properties and decomposition of DOC. We used 2 species of cottonwoods (Populus) and their naturally occurring hybrids that differ in leaf-litter phytochemistry and decomposition rate. We measured DOC and nutrient concentration in leaf leachates and determined the effect of DOC quality on heterotrophic respiration in 24-h incubations with stream sediments. Differences in DOC composition and quality were characterized with fluorescence spectroscopy. Rapidly decomposing leaves with lower tannin and lignin concentrations leached ~40 to 50% more DOC and total dissolved N than did slowly decomposing leaves. Rates of heterotrophic respiration were 25 to 50% higher on leachate from rapidly decomposing leaf types. Rates of heterotrophic respiration were related to metrics of aromaticity. Specifically, rates of respiration were correlated negatively with the Fluorescence Index and positively with Specific Ultraviolet Absorbance (SUVA254) and T280 tryptophan-like fluorescence peak. These results reveal that leaf-litter DOC is distinctly different from ambient streamwater DOC. The relationships between optical characteristics of leaf leachate and bioavailability are opposite those found in streamwater DOC. Differences in phytochemistry among leaf types can influence stream ecosystems with respect to DOC quantity, composition, and rates of stream respiration. These patterns suggest that the relationship between the chemical structure of DOC and its biogeochemistry is more complex than previously recognized. These unique properties of leaf-litter DOC will be important when assessing the effects of terrestrial C on aquatic ecosystems, especially during leaf fall
Fact sheet: Long-term herbivore exclusion for recovery of buckbrush populations during restoration of ponderosa pine forests in northern Arizona
Get PDFOpen conditions created by restoration activities in ponderosa pine (Pinus ponderosa Laws.) forests of
the American Southwest can lead to increases in
understory plant productivity but also attract large
ungulate herbivores. New plant growth stimulated
by tree thinning and prescribed fire can provide
greater forage quantity and quality for herbivores,
but grazing pressure on the recovering understory
may be high. Some management options during the
period when understories are recovering include
excluding herbivores from the site or protecting
individual plants for a number of years following
restoration treatments. Short-term protection of
grazed species may provide opportunity for their
escape through development of mass or structural
defenses such as spines or thorns. For example,
Huffman and Moore (2003) showed that two years
after forest treatments buckbrush (Ceanothus
fendleri Gray) plants protected from mule deer and Rocky Mountain elk had greater stem number, longer stems, and greater current-year biomass than unprotected plants. In contrast, branches of unprotected plants were heavily browsed and just 8 percent of these plants produced flowers. Herbivory pressure also may be lessened with increasing plant community diversity and as more forage options become available to herbivores. However, it is unclear how long protection of grazed plants is needed. Chancellor et al. (2008) showed that buckbrush plants exposed to herbivores after seven years of protection had similar stem lengths and stem numbers as plants that continued to be protected. Leaf area and leaf biomass, however, were significantly less on the recently exposed plants than on protected plants.
In this study, we wanted to determine if long-term protection from herbivores was required to restore buckbrush abundance and potential reproduction after forest restoration treatments that were comprised of tree thinning and prescribed fire Buckbrush is a shrub common in ponderosa pine forests of the southwestern U.S. It is important for soil nutrient budgets, understory structure, and habitat for wildlife. We re-measured buckbrush plots (10.8 ft2 (1 m2) in size) in the following groups: 1) unprotected (never protected from herbivores); 2) short-term protection (exclosures installed in 1999, removed in 2006); and 3) long-term protection (exclosures installed in 1999 and maintained throughout the 12-year study period)
The impact of inequity, relationship-technology fit, and trust on conflict: Working paper series--15-01
Get PDFAbstract E-business technology is playing an important role in manufacturer-reseller relationships. This research focuses on the behavioral aspects of technology deployment in channels of distribution. The paper examines the impact of inequity, relationship-technology fit, and trust on the key relationship variable of conflict. The data was collected from the resellers and multiple regression analysis was used to test the hypotheses. The results of the empirical test suggest that technology-relationship affects conflict indirectly by reducing perceived inequity and inequity directly increases conflict. Trust influences conflict both directly and indirectly by lowering perceived inequity. The paper briefly discusses the implications of these findings for practicing managers
Ubiquitous wi-fi implementations in hotels: Key planning factors
Get PDFThe Internet has changed the way in which people work and live. Many when traveling expect to be Internet-connected at all times without being tied down to physical wires, just as in their offices and homes. Wireless Fidelity (Wi-Fi) enables hotel guests with wireless-capable computers and devices to easily access high speed broadband networks within the coverage area. According to J.D. Power and Associates North America Hotel Guest Satisfaction Index Study, hotels that provide fast, reliable Internet service receive high ratings from guests. Wi-Fi, initially deployed in public spaces, is now an expected room amenity. Providing reliable and robust Wi-Fi coverage throughout a hotel requires careful implementation planning for technical as well as business-related factors. This article identifies and discusses key Wi-Fi planning factors and their implications for wireless network architecture decisions in hotel environments