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Search Results: 1 - 10 of 118605 matches for " Austin T. Humphries "
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The Effect of Structural Complexity, Prey Density, and “Predator-Free Space” on Prey Survivorship at Created Oyster Reef Mesocosms
Austin T. Humphries, Megan K. La Peyre, Gary A. Decossas
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0028339
Abstract: Interactions between predators and their prey are influenced by the habitat they occupy. Using created oyster (Crassostrea virginica) reef mesocosms, we conducted a series of laboratory experiments that created structure and manipulated complexity as well as prey density and “predator-free space” to examine the relationship between structural complexity and prey survivorship. Specifically, volume and spatial arrangement of oysters as well as prey density were manipulated, and the survivorship of prey (grass shrimp, Palaemonetes pugio) in the presence of a predator (wild red drum, Sciaenops ocellatus) was quantified. We found that the presence of structure increased prey survivorship, and that increasing complexity of this structure further increased survivorship, but only to a point. This agrees with the theory that structural complexity may influence predator-prey dynamics, but that a threshold exists with diminishing returns. These results held true even when prey density was scaled to structural complexity, or the amount of “predator-free space” was manipulated within our created reef mesocosms. The presence of structure and its complexity (oyster shell volume) were more important in facilitating prey survivorship than perceived refugia or density-dependent prey effects. A more accurate indicator of refugia might require “predator-free space” measures that also account for the available area within the structure itself (i.e., volume) and not just on the surface of a structure. Creating experiments that better mimic natural conditions and test a wider range of “predator-free space” are suggested to better understand the role of structural complexity in oyster reefs and other complex habitats.
Evaluating Social and Ecological Vulnerability of Coral Reef Fisheries to Climate Change
Joshua E. Cinner, Cindy Huchery, Emily S. Darling, Austin T. Humphries, Nicholas A. J. Graham, Christina C. Hicks, Nadine Marshall, Tim R. McClanahan
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0074321
Abstract: There is an increasing need to evaluate the links between the social and ecological dimensions of human vulnerability to climate change. We use an empirical case study of 12 coastal communities and associated coral reefs in Kenya to assess and compare five key ecological and social components of the vulnerability of coastal social-ecological systems to temperature induced coral mortality [specifically: 1) environmental exposure; 2) ecological sensitivity; 3) ecological recovery potential; 4) social sensitivity; and 5) social adaptive capacity]. We examined whether ecological components of vulnerability varied between government operated no-take marine reserves, community-based reserves, and openly fished areas. Overall, fished sites were marginally more vulnerable than community-based and government marine reserves. Social sensitivity was indicated by the occupational composition of each community, including the importance of fishing relative to other occupations, as well as the susceptibility of different fishing gears to the effects of coral bleaching on target fish species. Key components of social adaptive capacity varied considerably between the communities. Together, these results show that different communities have relative strengths and weaknesses in terms of social-ecological vulnerability to climate change.
An Evaluation of a Clinical Pharmacy-Directed Intervention on Blood Pressure Control
Kicklighter CE,Nelson KM,Humphries TL,Delate T
Pharmacy Practice (Granada) , 2006,
Abstract: Objective: To compare short and long term blood pressure control with clinical pharmacy specialist involvement to traditional physician management.Setting: A non-profit health maintenance organization in the United States covering approximately 385,000 lives.Methods: This analysis utilized a prospective parallel design. Adult patients with a baseline Blood pressure 140/90 mmHg and receiving at least one antihypertensive medication were eligible for the study. Eligible hypertension management patients at one medical office were referred to the office’s clinical pharmacy specialist (intervention cohort) while at another comparable medical office they received usual physician-directed care (control cohort). The primary outcome measure was achievement of a goal BP (<140/90 mmHg) during a six month follow-up. Medical records were also reviewed approximately 1.5 years post enrollment to assess long-term BP control after clinical pharmacy-managed patients returned to usual care. Multivariate analyses were performed to adjust for baseline cohort differences.Results: One hundred-thirteen and 111 subjects in the intervention and control cohorts completed the study, respectively. At the end of the follow-up period, clinical pharmacy-managed subjects were more likely to have achieved goal BP (64.6%) and received a thiazide diuretic (68.1%) compared to control subjects (40.7% and 33.3%, respectively) (adjusted p=0.002 and p<0.001, respectively). The proportion of clinical pharmacy-managed subjects with controlled BP decreased to 22.2% after returning to usual care (p<0.001).Conclusion: Clinical pharmacy involvement in hypertension management resulted in increased BP control. Loss of long-term control after discontinuation of clinical pharmacy management supports a change in care processes that prevent patients from being lost to follow-up.
Statistical analysis of an LES shallow cumulus cloud ensemble using a cloud tracking algorithm
J. T. Dawe ,P. H. Austin
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2012,
Abstract: A technique for the tracking of individual clouds in a Large Eddy Simulation (LES) is presented. We use this technique on an LES of a shallow cumulus cloud field based upon the Barbados Oceanographic and Meteorological Experiment (BOMEX) to calculate statistics of cloud height, lifetime, and other physical properties for individual clouds in the model. We also examine the question of nature versus nurture in shallow cumulus clouds: do properties at cloud base determine the upper-level properties of the clouds (nature), or are cloud properties determined by the environmental conditions they encounter (nurture). We find that clouds which ascend through an environment that has been pre-moistened by previous cloud activity are no more likely to reach the inversion than clouds that ascend through a drier environment. Cloud base thermodynamic properties are uncorrelated with upper-level cloud properties, while mean fractional entrainment and detrainment rates display moderate correlations with cloud properties up to the inversion. Conversely, cloud base area correlates well with upper-level cloud area and maximum cloud height. We conclude that cloud thermodynamic properties are primarily influenced by entrainment and detrainment processes, cloud area and height are primarily influenced by cloud base area, and thus nature and nurture both play roles in the dynamics of BOMEX shallow cumulus clouds.
Direct entrainment and detrainment rate distributions of individual shallow cumulus clouds in an LES
J. T. Dawe,P. H. Austin
Atmospheric Chemistry and Physics Discussions , 2013, DOI: 10.5194/acpd-13-5365-2013
Abstract: Probability distribution functions of shallow cumulus cloud core entrainment and detrainment rates are calculated using 4362 individual cumulus clouds isolated from LES using a cloud tracking algorithm. Calculation of the mutual information between fractional entrainment/detrainment and a variety of mean cloud core properties suggests that fractional entrainment rate is best predicted by the mean cloud buoyancy B and the environmental buoyancy lapse rate dθρdz at that level, while fractional detrainment is best predicted by the mean vertical velocity w and the critical mixing fraction χc. Fractional entrainment and detrainment rates are relatively insensitive to cloud core horizontal area, and the circumference of horizontal cloud core sections display an a0.69 dependence. This implies that cloud core mass entrainment flux E is proportional to cloud core cross-sectional area instead of cloud core surface area, as is generally assumed. Empirical best-fit relations for ε(B, dθρdz and δ(w, χc) are found for both individual shallow cumulus clouds and cloud ensembles. It is found that clouds with high buoyancy in strong stratification experience low entrainment rates, while clouds with high vertical velocities and critical mixing fractions experience low detrainment rates.
Statistical analysis of an LES shallow cumulus cloud ensemble using a cloud tracking algorithm
J. T. Dawe,P. H. Austin
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2012, DOI: 10.5194/acp-12-1101-2012
Abstract: A technique for the tracking of individual clouds in a Large Eddy Simulation (LES) is presented. We use this technique on an LES of a shallow cumulus cloud field based upon the Barbados Oceanographic and Meteorological Experiment (BOMEX) to calculate statistics of cloud height, lifetime, and other physical properties for individual clouds in the model. We also examine the question of nature versus nurture in shallow cumulus clouds: do properties at cloud base determine the upper-level properties of the clouds (nature), or are cloud properties determined by the environmental conditions they encounter (nurture). We find that clouds which ascend through an environment that has been pre-moistened by previous cloud activity are no more likely to reach the inversion than clouds that ascend through a drier environment. Cloud base thermodynamic properties are uncorrelated with upper-level cloud properties, while mean fractional entrainment and detrainment rates display moderate correlations with cloud properties up to the inversion. Conversely, cloud base area correlates well with upper-level cloud area and maximum cloud height. We conclude that cloud thermodynamic properties are primarily influenced by entrainment and detrainment processes, cloud area and height are primarily influenced by cloud base area, and thus nature and nurture both play roles in the dynamics of BOMEX shallow cumulus clouds.
Transport and Cultural Transition in the Novels of D. H. Lawrence
Andrew Humphries
United Academics Journal of Social Sciences , 2012,
Abstract: This essay discusses the work of a longer thesis which argues how transport reflects D.H. Lawrence’s engagement with an early twentieth century culture in rapid transition. Focusing on his novels Sons and Lovers (1913), The Rainbow (1915), Women in Love (1920), The Plumed Serpent (1926), and Lady Chatterley’s Lover (1928), it explains how the thesis takes a techno-historical approach to Lawrence’s work that engages with transport history as well as with philosophical and artistic movements of the period such as Modernism and Futurism, to argue that transport is used by Lawrence to enframe personal and cultural change as part of a wider shift enabled by travel towards great mobility during the first decades of the century. Transport vehicles interact, literally and metaphorically, with events and issues of cultural significance like the First World War and the Suffrage Movement and synthesize the protagonists’ real and inner journeys to give concrete focalization to the wider ontological quest at the heart of Lawrence’s fiction. Lawrence uses transport as a mobilizing and mobile phenomenon that invests cultural change with symbolic immediacy. Transport is used to explore shifts in gender space and power in a rapidly industrializing world. In Sons and Lovers extends industrial patriarchy and enhances male mobility at the expense of female space and in The Rainbow it enframes journeys of female liberation and empowerment. Women in Love involves transport to expose war subtexts that fulfil, literally and metaphorically, society’s apocalyptic and destructive impulses. In Lawrence’s Mexican novel The Plumed Serpent he places transport at the centre of the encounter with difference and dramatizes postcolonial tensions between invasive technological materialism and primitive cultural revival. The essay concludes with the idea that Lawrence’s final novel Lady Chatterley’s Lover locates transport as the agent of a postwar technological hegemony against which organic human futures must be tested. It examines a passage from the novel in closer detail to indicate the thesis approach to the integration of transport with considerations of thematic importance. Finally, the essay shows how the thesis concludes with an examination of Etruscan burial-transport rites that synthesize Lawrence’s interests in transport realism, cultural transit, and spiritual quest.
Maria del Mar Azcona, The Multi-Protagonist Film.
Reynold Humphries
European Journal of American Studies , 2011, DOI: 10.4000/ejas.9391
Abstract: In this stimulating and original volume the author presents “a contemporary tendency to abandon the single-protagonist structure on which most films narratives have traditionally relied and replace it by a wider assortment of characters with more or less independent narrative lines” (1). Of particular importance is the fact that the films falling into this relatively new category present “a multiplicity of characters of similar narrative relevance ... without establishing a strict narrative h...
The Distribution of Weighted Sums of the Liouville Function and Pólya's Conjecture
Peter Humphries
Mathematics , 2011, DOI: 10.1016/j.jnt.2012.08.011
Abstract: Under the assumption of the Riemann Hypothesis, the Linear Independence Hypothesis, and a bound on negative discrete moments of the Riemann zeta function, we prove the existence of a limiting logarithmic distribution of the normalisation of the weighted sum of the Liouville function, $L_{\alpha}(x) = \sum_{n \leq x}{\lambda(n) / n^{\alpha}}$, for $0 \leq \alpha < 1/2$. Using this, we conditionally show that these weighted sums have a negative bias, but that for each $0 \leq \alpha < 1/2$, the set of all $x \geq 1$ for which $L_{\alpha}(x)$ is positive has positive logarithmic density. For $\alpha = 0$, this gives a conditional proof that the set of counterexamples to P\'olya's conjecture has positive logarithmic density. Finally, when $\alpha = 1/2$, we conditionally prove that $L_{\alpha}(x)$ is negative outside a set of logarithmic density zero, thereby lending support to a conjecture of Mossinghoff and Trudgian that this weighted sum is nonpositive for all $x \geq 17$.
On the Mertens Conjecture for Elliptic Curves over Finite Fields
Peter Humphries
Mathematics , 2012, DOI: 10.1017/S0004972712001116
Abstract: We introduce an analogue of the Mertens conjecture for elliptic curves over finite fields. Using a result of Waterhouse, we classify the isogeny classes of elliptic curves for which this conjecture holds in terms the size of the finite field and the trace of the Frobenius endomorphism acting on the curve.
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