The bryophyte flora of Fall Creek Falls State, : Park Van Buren and Bledsoe counties, Tennessee, USA

Fall Creek Falls State Park is located in Van Buren and Bledsoe Counties, Tennessee, U.S.A. It is an 8800+ ha (22,000+ acre) resort park in east Tennessee that lies in two physiographic provinces, the Cumberland Plateau and the Eastern Highland Rim. The park contains a high diversity of habitats, including unique habitat types such as waterfalls, cave entrances, and limestone sinks. The park flora is little known, except for a study by Caplenor in 1955, which focused on the vascular flora of the park. An initial examination showed evidence of visitation by Dr. A. J. Sharp and Dr. A. Clebsch around 50 years ago, with only minor contributions from the area over the last 50 years. The results of all previous work showed only a combined total of 94 bryophyte taxa for Van Buren and Bledsoe Counties. This study has three main objectives: catalogue the bryophyte taxa of Fall Creek Falls State Park, as a resource for future management planning within the park; expand the bryophyte floras of Van Buren and Bledsoe Counties; and analyze phytogeographical data on the distribution of the flora of the park. Collections were made over a 16 month period from May of 2001 to September 2002. They were made using a focused collecting technique that relied on information from topographic, soils, and geology maps, as well as information from park officials and others familiar with the vegetation of the area. Rich sites were sampled carefully, in order to collect all possible additions to the park flora. This collecting protocol helped to meet the first two objectives for this study. A total of 228 taxa were collected, adding 164 taxa to the flora of Van Buren County and 16 to Bledsoe County. These taxa were then examined using distributional data from a variety ofbryological literature and it was found that there were six phytogeographical categories in which they could be grouped: cosmopolitan, those taxa with a distribution throughout the northern hemisphere and some presence in the southern hemisphere; widespread global distribution, similar to cosmopolitan, but lacking distribution on one northern hemisphere continent; widespread northern hemisphere, similar to cosmopolitan, but without a known presence in the southern hemisphere; global disjuncts, taxa with distributions that contain large geographic discontinuity between locations; widespread North American; and Eastern North American endemics, which can be further subdivided into Appalachian and Southern Appalachian endemics. Overall, Fall Creek Falls State Park is diverse in habitat types which equates to a rich bryophyte flora, with a wide global distribution

Optimum structural design with static aeroelastic constraints

The static aeroelastic performance characteristics, divergence velocity, control effectiveness and lift effectiveness are considered in obtaining an optimum weight structure. A typical swept wing structure is used with upper and lower skins, spar and rib thicknesses, and spar cap and vertical post cross-sectional areas as the design parameters. Incompressible aerodynamic strip theory is used to derive the constraint formulations, and aerodynamic load matrices. A Sequential Unconstrained Minimization Technique (SUMT) algorithm is used to optimize the wing structure to meet the desired performance constraints

Impact of parameter variations on circuits and microarchitecture

Parameter variations, which are increasing along with advances in process technologies, affect both timing and power. Variability must be considered at both the circuit and microarchitectural design levels to keep pace with performance scaling and to keep power consumption within reasonable limits. This article presents an overview of the main sources of variability and surveys variation-tolerant circuit and microarchitectural approaches.Peer ReviewedPostprint (published version

Temperature dependence of field-response mechanisms in 0.4Ba(Zr\u3csub\u3e0.2\u3c/sub\u3eTi\u3csub\u3e0.8\u3c/sub\u3e)O\u3csub\u3e3\u3c/sub\u3e-0.6(Ba\u3csub\u3e0.7\u3c/sub\u3eCa\u3csub\u3e0.3\u3c/sub\u3e)TiO\u3csub\u3e3\u3c/sub\u3e

Understanding the temperature dependence of how ferroelectric materials respond to electric fields is critical for determining how best to use these materials in applications. Here, temperature dependent in situ x-ray diffraction is used to study how field-response mechanism Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 evolves with temperature. Increasing the measurement temperature was found to slightly reduce the extent of domain reversal and the magnitude of the 111 lattice strain. Instead, these results indicate that temperature predominantly impacted the angular dependence of the 002/200 lattice strain. We attribute the observed differences in 002/200 lattice strain to the flattening of the free-energy near the tetragonal-orthorhombic phase boundary, where the flattening of the energy landscape promotes a polarization rotation response during the application of electric fields at room temperature

Stress asymmetry in cyclic deformation of b.c.c. metals

Asymmetric slip in b.c.c. metals is related to both the symmetry about screw dislocations and elastic anisotropy. The elastic anisotropy differs quite substantially from one b.c.c. metal to the next and this anisotropy has been observed in measurements of asymmetric stresses in plastic deformation experiments. In this paper, data from cyclic deformation of b.c.c. metals, with special emphasis on tungsten which is elastically isotropic, are used to demonstrate the role of screw dislocation geometry and elastic anisotropy on stress asymmetry. The interaction of dislocation geometry and thermal activation of screw dislocation motion is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30320/1/0000722.pd

Cognitive archaeology: estimating the effects of blood-lead concentrations on the neuropsychological function of an officer of the 1845 Franklin expedition

Lead poisoning has been implicated in the loss in the Arctic of all 129 officers and men of the British Royal Naval “Franklin expedition” of 1845. In a unique study, D’Ortenzio et al. (2018) estimated blood-lead concentrations of an officer of the expedition over the three months prior to his death which is thought to have occurred before the desertion of the expedition’s ships. The present study applies regression coefficients which quantify the relationship between blood lead and neuropsychological function to the data of D’Ortenzio et al. to estimate whether the officer’s lead exposure would have impaired his cognitive performance in the critical period prior to the desertion. It is shown that the blood-lead concentrations would have been associated with only small deficits in higher-order cognitive processes including attention, visual scanning, memory and decision-making which would not have been of functional significance. Greater deficits were associated with psychomotor functions involving eye-hand co-ordination and fine motor control which, although not defined formally as “impairment”, might have affected accuracy when using firearms or operating instruments relevant to the scientific objectives of the expedition. The study also reviews evidence that the levels of lead in the Franklin crew, while high relative to today, were typical of those of the lead-exposed Victorian population from which they were recruited. The results contribute to evidence that lead exposure did not play a significant role in the loss of the Franklin expedition

Do you cite what you tweet? Investigating the relationship between tweeting and citing research articles

The last decade of altmetrics research has demonstrated that altmetrics have a low to moderate correlation with citations, depending on the platform and the discipline, among other factors. Most past studies used academic works as their unit of analysis to determine whether the attention they received on Twitter was a good predictor of academic engagement. Our work revisits the relationship between tweets and citations where the tweet itself is the unit of analysis, and the question is to determine if, at the individual level, the act of tweeting an academic work can shed light on the likelihood of the act of citing that same work. We model this relationship by considering the research activity of the tweeter and its relationship to the tweeted work. Results show that tweeters are more likely to cite works affiliated with their same institution, works published in journals in which they also have published, and works in which they hold authorship. It finds that the older the academic age of a tweeter the less likely they are to cite what they tweet, though there is a positive relationship between citations and the number of works they have published and references they have accumulated over time

Vegetation and environmental patterns on soils derived from Hawkesbury Sandstone and Narrabeen substrata in Ku-ring-gai Chase National Park, New South Wales

[Abstract]: The vegetation patterns in the Central Coast region of New South Wales have been extensively studied with respect to single environmental variables, particularly soil nutrients. However, few data are available on the effects of multiple environmental variables. This study examines the relationships between vegetation and multiple environmental variables in natural vegetation on two underlying rock types, Hawkesbury sandstone and Narrabeen group shales and sandstones, in Ku-ring-gai Chase National Park, Sydney. Floristic composition and 17 environmental factors were characterized using duplicate 500 m2 quadrats from fifty sites representing a wide range of vegetation types. The patterns in vegetation and environmental factors were examined through multivariate analyses: indicator species analysis was used to provide an objective classification of plant community types, and the relationships between vegetation and environmental factors within the two soil types were examined through indirect and direct gradient analyses. Eleven plant communities were identified, which showed strong agreement with previous studies. The measured environmental factors showed strong correlations with vegetation patterns: within both soil types, the measured environmental variables explained approximately 32 - 35% of the variation in vegetation. No single measured environmental variable adequately described the observed gradients in vegetation; rather, vegetation gradients showed strong correlations with complex environmental gradients. These complex environmental gradients included nutrient, moisture and soil physical and site variables. These results suggest a simple 'nutrient' hypothesis regarding vegetation patterns in the Central Coast region is inadequate to explain variation in vegetation within soil types

Persistent androgen receptor-mediated transcription in castration-resistant prostate cancer under androgen-deprived conditions

The androgen receptor (AR) is a ligand-inducible transcription factor that mediates androgen action in target tissues. Upon ligand binding, the AR binds to thousands of genomic loci and activates a cell-type specific gene program. Prostate cancer growth and progression depend on androgen-induced AR signaling. Treatment of advanced prostate cancer through medical or surgical castration leads to initial response and durable remission, but resistance inevitably develops. In castration-resistant prostate cancer (CRPC), AR activity remains critical for tumor growth despite androgen deprivation. Although previous studies have focused on ligand-dependent AR signaling, in this study we explore AR function under the androgen-deprived conditions characteristic of CRPC. Our data demonstrate that AR persistently occupies a distinct set of genomic loci after androgen deprivation in CRPC. These androgen-independent AR occupied regions have constitutively open chromatin structures that lack the canonical androgen response element and are independent of FoxA1, a transcription factor involved in ligand-dependent AR targeting. Many AR binding events occur at proximal promoters, which can act as enhancers to augment transcriptional activities of other promoters through DNA looping. We further show that androgen-independent AR binding directs a gene expression program in CRPC, which is necessary for the growth of CRPC after androgen withdrawal