Ecology and evolution of plant-insect interactions among hybrid populations of the invasive plant, tamarisk (Tamarix sp.), in the western United States, The

2012 Summer.Includes bibliographical references.Tamarisk is one of the most abundant invasive tree species in the western United States. Several species belonging to the genus Tamarix were imported intentionally to the U.S. in the mid-nineteenth century. Currently, most U.S. populations are comprised of a hybrid swarm between T. ramosissima and T. chinensis and other species. Negative consequences of hybrid tamarisk invasion include alteration of ecosystem functioning and decreases in native biodiversity. Very few natural enemies attack this invasive plant, contributing to its success on the landscape. In an attempt to provide top-down population control, a specialized herbivore that coevolved with tamarisk in its native range was intentionally released in the introduced range (i.e. biological control). I investigated interactions between tamarisk hybrids and herbivores in order to better understand the dynamics that contribute to the control of this exotic weed. In Chapter 1, which was published in Volume 57 of The Southwestern Naturalist, I describe how a native stem-boring beetle was found attacking tamarisk populations in eastern Colorado, western Kansas, and southwest Nebraska. This is an important discovery because very few native insects have been reported to consume this plant and never at the levels of the stem-borer. The beetle may reduce tamarisk growth and fecundity on the Great Plains, providing evidence for the biotic resistance hypothesis. In Chapter 2, I investigate the interaction between drought and herbivory by the biological control agent, Diorhabda carinulata. Under which environmental conditions or geographical locations can biological control be maximized? Finally, in Chapter 3, I speculate whether hybrid tamarisk individuals or populations differ in plant performance and herbivore defense traits. Since the biological control agent coevolved with one parent species, T. ramosissima, I hypothesized that some hybrids may be more or less susceptible to attack by this herbivore. Success of biological control may hinge upon the level of species introgression, and if hybridization occurs predictably across the landscape, managers can exploit this information for tamarisk control. My research not only attempts to improve control strategies, but also addresses fundamental questions in plant-insect ecology and evolution

A Comparison of Heart Rate Variability Between High Fit and Recreational Fit Cyclists

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Debris discs around nearby Solar analogues

An unbiased search for debris discs around nearby Sun-like stars is reported. Thirteen G-dwarfs at 12-15 parsecs distance were searched at 850 \umum wavelength, and a disc is confirmed around HD 30495. The estimated dust mass is 0.008 M$_{\oplus}$ with a net limit \la 0.0025 M$_{\oplus}$ for the average disc of the other stars. The results suggest there is not a large missed population of substantial cold discs around Sun-like stars -- HD 30495 is a bright rather than unusually cool disc, and may belong to a few hundred Myr-old population of greater dust luminosity. The far-infared and millimetre survey data for Sun-like stars are well fitted by either steady state or stirred models, provided that typical comet belts are comparable in size to that in the Solar System.Comment: published in MNRA

Interactions between Sheets of Phonons in Liquid 4He

We have created two sheets of 1 K phonons in liquid 4He at 55 mK such that they intersect each other as they move towards a common point. If the two sheets have a small angle between them, they interact strongly and create a hot line in the liquid helium. This line is continuously fed with energy from the two sheets and loses energy by creating high-energy phonons. If the angle between the sheets is larger than 30 they do not interact but pass through each other. These results give direct evidence for the composition of the sheets: they comprise strongly interacting low-energy phonons which occupy a narrow cone in momentum space

\u3ci\u3eChrysobothris rugosiceps\u3c/i\u3e Melsheimer (Coleoptera: Buprestidae) found in Washington state

Chrysobothris rugosiceps Melsheimer (Coleoptera: Buprestidae) is reported from Washington State from a single specimen caught in a Lindgren funnel trap. Clearly this represents an exotic to the region, as the closest known occurrence of this native U.S.A. species is in the Dakotas

The exotic \u3ci\u3eAgrilus cyanescens\u3c/i\u3e (Ratzeburg) (Coleoptera: Buprestidae) is discovered in Oregon

In two separate occurrences, graduates of the Oregon Forest Pest Detector program discovered the exotic Agrilus cyanescens (Ratzeburg) (Coleoptera: Buprestidae) in Portland, Oregon, damaging a backyard shrub, Lonicera involucrata (Rich.) Banks ex Spreng. (Caprifoliaceae). Although first detected in the USA 99 years ago, the known occurrence nearest to Oregon is in Utah

Modeling Collisional Cascades In Debris Disks: Steep Dust-Size Distributions

We explore the evolution of the mass distribution of dust in collision-dominated debris disks, using the collisional code introduced in our previous paper. We analyze the equilibrium distribution and its dependence on model parameters by evolving over 100 models to 10 Gyr. With our numerical models, we confirm that systems reach collisional equilibrium with a mass distribution that is steeper than the traditional solution by Dohnanyi (1969). Our model yields a quasi steady-state slope of n(m) ~ m^{-1.88} [n(a) ~ a^{-3.65}] as a robust solution for a wide range of possible model parameters. We also show that a simple power-law function can be an appropriate approximation for the mass distribution of particles in certain regimes. The steeper solution has observable effects in the submillimeter and millimeter wavelength regimes of the electromagnetic spectrum. We assemble data for nine debris disks that have been observed at these wavelengths and, using a simplified absorption efficiency model, show that the predicted slope of the particle mass distribution generates SEDs that are in agreement with the observed ones.Comment: 12 pages, 10 figures, Accepted by ApJ, emulateap

The Four Cs of HIV Prevention with African Americans: Crisis, Condoms, Culture, and Community

HIV/AIDS continues to be a devastating epidemic with African American communities carrying the brunt of the impact. Despite extensive biobehavioral research, current strategies have not resulted in significantly decreasing HIV/AIDS cases among African Americans. The next generation of HIV prevention and risk reduction interventions must move beyond basic sex education and condom use and availability. Successful interventions targeting African Americans must optimize strategies that integrate socio-cultural factors and address institutional and historical barriers that hinder or support HIV risk reduction behaviors. Community-based participatory research to decrease the HIV/AIDS disparity by building community capacity and infrastructure and advocating for and distributing equitably, power and resources, must be promoted. Recommendations for paradigm shifts in using innovative theories and conceptual frameworks and for training researchers, clinicians, grant and journal reviewers, and community members are made so that culturally congruent interventions may be tested and implemented at the community level

Search for domain wall dark matter with atomic clocks on board global positioning system satellites

Cosmological observations indicate that 85% of all matter in the Universe is dark matter (DM), yet its microscopic composition remains a mystery. One hypothesis is that DM arises from ultralight quantum fields that form macroscopic objects such as topological defects. Here we use GPS as a ~ 50,000 km aperture DM detector to search for such defects in the form of domain walls. GPS navigation relies on precision timing signals furnished by atomic clocks hosted on board GPS satellites. As the Earth moves through the galactic DM halo, interactions with topological defects could cause atomic clock glitches that propagate through the GPS satellite constellation at galactic velocities ~ 300 km/s. Mining 16 years of archival GPS data, we find no evidence for DM in the form of domain walls at our current sensitivity level. This allows us to improve the limits on certain quadratic scalar couplings of domain wall DM to standard model particles by several orders of magnitude.Comment: 7 pages (main text), and 12 pages for Supplementary Information. v3: Update titl

Thromboprophylaxis prescribing among junior doctors:the impact of educational interventions

BACKGROUND: Venous thromboembolism (VTE) prophylaxis in an important aspect of the care of hospitalised patients, for which the National Institute for Health and Care Excellence (NICE) has issued guidance. Guidance compliance continues to be a concern. Junior doctors are the main group responsible for prescribing thromboprophylaxis. We aimed to compare local pharmacological thromboprophylaxis prescribing against NICE guidelines in a surgical department at a district general hospital, and determine whether interventions aimed at improving compliance were effective. METHODS: Over four months, a two cycle audit of prescribing patterns for VTE prophylaxis was performed using data collected at four intervals: 1. Baseline 2. Following pro-forma introduction and feedback 3. A second baseline data collection. 4. Following VTE prophylaxis teaching. RESULTS: A total of 394 admissions were included. Correct identification and prescribing for at-risk patients ranged between 76 and 93 %, whilst risk assessment documentation and explanation to patients occurred in fewer than 50 and 66 % respectively. Prescribing and risk assessment improved in the first cycle (chi2 = 6.75, p = 0.009 and chi2 = 10.70, p = 0.001 respectively), a consequence of one specialty improving following additional feedback. Teaching was not associated with improvements. Overall compliance with NICE guidelines was achieved in no more than 25 % of admissions. CONCLUSIONS: Despite junior doctors generally prescribing VTE thromboprophylaxis appropriately, overall compliance with guidelines remained poor regardless of educational interventions. Verbal feedback was the only intervention associated with modest improvements. A pressurised work environment may limit the impact of educational interventions. Guidance simplification or devolving responsibility to other members of staff may improve compliance. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12913-016-1480-9) contains supplementary material, which is available to authorized users