4,073 research outputs found
Nonminimally coupled topological-defect boson stars: Static solutions
We consider spherically symmetric static composite structures consisting of a
boson star and a global monopole, minimally or non-minimally coupled to the
general relativistic gravitational field. In the non-minimally coupled case,
Marunovic and Murkovic have shown that these objects, so-called boson D-stars,
can be sufficiently gravitationally compact so as to potentially mimic black
holes. Here, we present the results of an extensive numerical parameter space
survey which reveals additional new and unexpected phenomenology in the model.
In particular, focusing on families of boson D-stars which are parameterized by
the central amplitude of the boson field, we find configurations for both the
minimally and non-minimally coupled cases that contain one or more shells of
bosonic matter located far from the origin. In parameter space, each shell
spontaneously appears as one tunes through some critical central amplitude of
the boson field. In some cases the shells apparently materialize at spatial
infinity: in these instances their areal radii are observed to obey a universal
scaling law in the vicinity of the critical amplitude. We derive this law from
the equations of motion and the asymptotic behavior of the fields.Comment: 17 pages, 24 figure
Open, Risky, and Antioppressive: Hope for an Agonistic Deliberative Model. A Response to Empowering Young People through Conflict and Conciliation: Attending to the Political and Agonism in Democratic Education
First, I review the context for the need of new deliberative models, specifically agonistic deliberative models, for public discourse and for use in training students for public discourse. I then highlight five specific points that I trouble and enrich, principally through the work of Giroux, Arendt, Biesta, and Duarte. While I agree that there is great value in Lo’s description of the agonistic deliberative model, I advocate for what Biesta would call a weaker model of deliberation, one that sets the conditions for transformative education but one that does not act as an instrument for it
Optical Sensing of Capillary Waves
I relay various topics I learned about this semester and summarize the specialties of Clemson’s Micro-Photonics Laboratory. I report pertinent information for characterizing capillary waves with lasers and one recent method of characterizing them. Lastly, I outline a potential plan for mathematically modeling a laser’s reflection off of capillary waves, and potential plans moving forward
Soil ecology of the exotic dune grass Leymus arenarius.
Exotic plants can alter the structure and function of native communities both above- and belowground, which is particularly important in primary successional sand dune ecosystems where plant-soil interactions are critical drivers of successional dynamics. In Great Lakes sand dunes, the native foundation grass Ammophila breviligulata dominates early in succession until an accumulation of detrimental soil organisms causes its die-back of the grasses. Die-back of this native foundation species can be slowed by mutualistic interactions between plants and mycorrhizal fungi. Changes to the plant community resulting from invasion, and subsequent effects on the soil community have the potential to disrupt the successional dynamics of dune systems. Leymus arenarius is a dune-building grass native to northern European sand dunes, and is currently invading Great Lakes dunes. This dissertation examines the effects of L. arenarius invasion on soil community structure, multi-trophic interactions within the soil, and plant community development. In a greenhouse study manipulating the presence/absence of soil organisms, I found evidence of altered multi-trophic interactions. Specifically, arbuscular mycorrhizal fungi provided greater protection from plant-parasitic nematodes to L. arenarius, resulting in weaker biomass reductions relative to A. breviligulata. In a field survey, I found that L. arenarius had little effect on the structure of soil nematode communities and soil bacterial functional diversity relative to uninvaded areas. In a growth chamber experiment, I found that direct competitive effects from L. arenarius were generally similar to effects from A. breviligulata, for later successional native species. However, L. arenarius more strongly suppressed growth of secondary invaders, relative to suppression by A. breviligulata. Soil conditioning effects from L. arenarius were present, but were generally weak suggesting that indirect effects of invasion on soil community composition are less important than direct competitive effects. Experimentally-derived differences in multi-trophic interactions between L. arenarius and A. breviligulata suggested that the invasion of L. arenarius into communities dominated by A. breviligulata would result in altered plant-soil interactions. However, the invasion of L. arenarius did not result in large impacts on plant and soil communities. Overall, these results suggest that L. arenarius has relatively high functional similarity to its native counterpart, A. breviligulata
Studies of rumen epithelial cell metabolism
The metabolism of rumen epithelial cells was studied in two experiments. The first experiment compared the metabolism of cells harvested from steers and ewes to determine the existence of a species effect. The second experiment compared the metabolism of cells harvested from four locations within the ewe rumen to determine if cellular origin has an effect on metabolism. In the first study, rumen epithelial cells were harvested from the anterior cranial pillar (ACP) of 4 ewes and 4 steers fed fescue hay. Whole tissue from ewes (~150 cm2) was excised following death by captive bolt and exsanguination. Rumen epithelial cells were obtained from steers from clipped papillae harvested after exteriorizing the rumen through a rumen fistula. In the second study, tissue (~150 c,2) was excised from the ACP, ventral sac floor (VSF), caudal pillar surface (CPS), and dorsal sac ceiling (DSC) of each ewe rumen. Cells were isolated using a serial tryptic digestion procedure in both experiments. Thereafter, 1 mL of cell isolate was incubated for 2 h in 6 mL of media containing 25 mM propionate and 10 mM butyrate. Incubations were terminated at 0, 30, 60, 90, and 120 min and analyzed for B-hydroxybutyrate (BOHB) and acetoacetate (ACAC) as mitochondrial, and lactate (LACT) and pyruvate (PYR) as cytosolic redox estimators. All metabolite concentrations and ratios increased over the incubations indicating continuous cellular activity. Cell yield averaged 21 and 5 x 106 cells/mL for ewes and steers respectively, and mean cell viability for both was 92% in the first study. Final 2 h concentrations (nmol/106 cells) f BOHB, ACAC, LACT, and PYR were 123 ± 20, 36 ± 17, 25 ± 7, and 2.9 ± 1.1 for ewes, and 177 ± 20, 90 ± 18, 74 ± 7, and 5.6 ± 1.1 for steers. Ratios of BOHB to ACAC and LACT to PYR were 3.4 and 8.8 for ewes, and 1.8 and 13.2 for steers (P \u3e .10). Steers produced BOHB (P \u3c .06), ACAC (P \u3c .01), LACT (P \u3c .01), and PYR (P \u3c .10) at higher levels than did ewes indicating that a species difference existed in the metabolism of rumen epithelial cells. Cell yield was 22, 22, 24, and 14 ± 6 x 106 cells/mL and viability was 92, 92, 94, and 87% for ACP, VSF, CPS, and DSC, respectively in the second study. Final 2 h concentrations (nmoles/106 cells) were 123, 113, 163, and 158 ± 35 for BOHB; 38, 42, 24, and 45 ± 10 for ACAC; 25.3, 20.6, 10.1, and 20.4 ± 5.6 for LACT; and 2.54, .98, 1.06, and 1.31 ± .61 for PYR in the ACP, VSF, CPS, and DSC incubations, respectively. The amount of metabolite produced did not differ (P \u3e .05) between tissues indicating that cellular location was not a significant factor in the metabolism of rumen epithelial cells. These experiments were designed to study various aspects of rumen epithelial cell metabolism. Cells from steers produced more BOHB, ACAC, LACT, and PYR than those from ewes. However, metabolism of cells isolated from different areas of the ewe rumen did not differ
COLONIZATION OF NORTHERN LOUISIANA BY THE MEDITERRANEAN GECKO, HEMIDACTYLUS TURCICUS
The Mediterranean Gecko, Hemidactylus turcicus, is known to have colonized nearly every state in the southern United States. In Louisiana, the Mediterranean Gecko has been documented in many of the southern parishes, but records for the northern portion of the state are limited. We sampled northern Louisiana parishes to document the presence of the Mediterranean Gecko. We sampled a total of 21 parishes in northern Louisiana and found geckos in 17 of those parishes, 16 of which represent new distribution records for the species. This indicates a significant range expansion of this introduced species throughout northern Louisiana. Geckos were found across a temperature range of 14.0–28.0°C and had a strong association with buildings. The species’ affinity for anthropogenic association and the continual nature of anthropogenic expansion facilitate the high vagility of this species. The result is a successful colonization throughout much of Louisiana and likely continued range expansion throughout the southern United States
Critical Democratic Education and LGBTQ+-Inclusive Curriculum. A Book Review of \u3cem\u3eCritical Democratic Education and LGBTQ-Inclusive Curriculum: Opportunities and Constraints\u3c/em\u3e
With the aim of promoting the democratic education values of inclusion equity and social justice using a queer theoretical framework to identify and deconstruct normalizing forces, author Camicia sets the reader up for a deep analysis of educational practice, policy, and curriculum using Utah and California as concrete illustrations of democratic inclusive curriculum. Camicia\u27s book ends with an epilogue “discussing a rationale for using auto-ethnography within curriculum in order to increase inclusion, which opens up excellent possibilities for future research
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