Magnetic properties of pure and Gd doped EuO probed by NMR

An Eu NMR study in the ferromagnetic phase of pure and Gd doped EuO was performed. A complete description of the NMR lineshape of pure EuO allowed for the influence of doping EuO with Gd impurities to be highlighted. The presence of a temperature dependent static magnetic inhomogeneity in Gd doped EuO was demonstrated by studying the temperature dependence of the lineshapes. The results suggest that the inhomogeneity in 0.6% Gd doped EuO is linked to colossal magnetoresistance. The measurement of the spin-lattice relaxation times as a function of temperature led to the determination of the value of the exchange integral J as a function of Gd doping. It was found that J is temperature independent and spatially homogeneous for all the samples and that its value increases abruptly with increasing Gd doping.Comment: 14 pages, 10 figures, to be published in Physical Review

Microwave and Millimeter Wave Techniques

Contains reports on three research projects.Joint Services Electronics Program (Contract DAAB07-75-C-1346

Cloud condensation nuclei as a modulator of ice processes in Arctic mixed-phase clouds

We propose that cloud condensation nuclei (CCN) concentrations are important for modulating ice formation of Arctic mixed-phase clouds, through modification of the droplet size distribution. Aircraft observations from the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) study in northern Alaska in April 2008 allow for identification and characterization of both aerosol and trace gas pollutants, which are then compared with cloud microphysical properties. Consistent with previous studies, we find that the concentration of precipitating ice particles (>400 μm) is correlated with the concentration of large droplets (>30 μm). We are further able to link the observed microphysical conditions to aerosol pollution, originating mainly from long range transport of biomass burning emissions. The case studies demonstrate that polluted mixed-phase clouds have narrower droplet size distributions and contain 1–2 orders of magnitude fewer precipitating ice particles than clean clouds at the same temperature. This suggests an aerosol indirect effect leading to greater cloud lifetime, greater cloud emissivity, and reduced precipitation. This result is opposite to the glaciation indirect effect, whereby polluted clouds are expected to precipitate more readily due to an increase in the concentration of particles acting as ice nuclei

Two-step stabilization of orbital order and the dynamical frustration of spin in the model charge-transfer insulator KCuF3

We report a combined experimental and theoretical study of KCuF3, which offers - because of this material's relatively simple lattice structure and valence configuration (d9, i.e., one hole in the d-shell) - a particularly clear view of the essential role of the orbital degree of freedom in governing the dynamical coupling between the spin and lattice degrees of freedom. We present Raman and x-ray scattering evidence that the phase behaviour of KCuF3 is dominated above the Neel temperature (T_N = 40 K) by coupled orbital/lattice fluctuations that are likely associated with rotations of the CuF6 octahedra, and we show that these orbital fluctuations are interrupted by a static structural distortion that occurs just above T_N. A detailed model of the orbital and magnetic phases of KCuF3 reveals that these orbital fluctuations - and the related frustration of in-plane spin-order-are associated with the presence of nearly degenerate low-energy spin-orbital states that are highly susceptible to thermal fluctuations over a wide range of temperatures. A striking implication of these results is that the ground state of KCuF3 at ambient pressure lies near a quantum critical point associated with an orbital/spin liquid phase that is obscured by emergent Neel ordering of the spins; this exotic liquid phase might be accessible via pressure studies.Comment: 13 pages, 3 figure

Area-wide eradication of the invasive European grapevine moth Lobesia botrana in California, USA

17openBothIn the fall of 2009, the first confirmed North American detection of the European grapevine moth (EGVM) Lobesia botrana (Denis & Schiffermüller) occurred in Napa County, California, USA. Based on its status as a significant grape pest in other parts of the world, the establishment of EGVM in California presented significant production and export issues for grapes, as well as for other fresh market agricultural commodities. Over the following seven years, an intensive California state-wide survey and area-wide eradication campaign was undertaken in partnership with agricultural officials at local, state and federal levels, university scientists and the wine, table grape and raisin industries. These efforts resulted in a dramatic decline in moth captures in pheromone traps from over 100 000 moths in 2010, to one in 2014, and none in 2015. In August of 2016, eradication was declared for all previously infested areas in California. The decision to pursue the eradication effort was based on the limited host range and geographic area of the EGVM infestation, the availability of effective tools for monitoring and control, and the strong support of the affected grape production and export industries. The eradication campaign employed coordinated logistical, regulatory, and technical efforts that included: 1) state-wide-monitoring using a network of pheromone-baited traps and in field monitoring; these findings were recorded in a geographic information system that was used to regularly communicate survey results to programme officials; 2) an area-wide application of mating disruption dispensers to infested vineyards, including use in urban environments within infested zones; 3) implementation by coordinators of area-wide insecticide treatments with application timing determined by degree-day modelling for each infested region; 4) a robust regulatory programme that initiated and maintained a quarantine of infested areas that regulated movement of fruit, farming equipment and winery processing waste; 5) an extensive outreach programme to grape growers, wineries, pest control specialists and the public; 6) formation of a technical working group that provided recommendations to the operational programme. An extensive methods development effort supported the programme. This included developing enhanced detection methods for vineyards under mating disruption, testing efficacy and residual control of insecticides, testing mating disruption formulations, evaluating the impacts of winery processing methods on EGVM mortality, developing methods to determine the timing of the development of successive EGVM generations (or biofix) under California conditions to improve degree-day models, developing EGVM rearing methods, testing the quality of pheromone lures and trap monitoring; and a spatial analysis of trapping data to determine programme effectiveness and to analyse invasion pathwaysopenSimmons, G.S.; Varela, L.; Daugherty, M.; Cooper, M.; Lance, D.; Mastro, V.; Carde, R.T.; Lucchi, A.; Ioriatti, C.; Bagnoli, B.; Steinhauer, R.; Broadway, R.; Stone Smith, B.; Hoffman, K.; Clark, G.; Whitmer, D.; Johnson, R.Simmons, G.S.; Varela, L.; Daugherty, M.; Cooper, M.; Lance, D.; Mastro, V.; Carde, R.T.; Lucchi, A.; Ioriatti, C.; Bagnoli, B.; Steinhauer, R.; Broadway, R.; Stone Smith, B.; Hoffman, K.; Clark, G.; Whitmer, D.; Johnson, R

A survey of South Carolina pharmacists\u27 readiness to prescribe human immunodeficiency virus pre-exposure prophylaxis

Introduction: Human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) is largely underutilized in the Southern United States. Given their community presence, pharmacists are well positioned to provide PrEP within rural, Southern regions. However, pharmacists\u27 readiness to prescribe PrEP in these communities remains unknown. Objective: To determine the perceived feasibility and acceptability of prescribing PrEP by pharmacists in South Carolina (SC). Methods: We distributed a 43-question online descriptive survey through the University of South Carolina Kennedy Pharmacy Innovation Center\u27s listserv of licensed SC pharmacists. We assessed pharmacists\u27 comfort, knowledge, and readiness to provide PrEP. Results: A total of 150 pharmacists responded to the survey. The majority were White (73%, n = 110), female (62%, n = 93), and non-Hispanic (83%, n = 125). Pharmacists practiced in retail (25%, n = 37), hospital (22%, n = 33), independent (17%, n = 25), community (13%, n = 19), specialty (6%, n = 9), and academic settings (3%, n = 4); 11% (n = 17) practiced in rural locales. Pharmacists viewed PrEP as both effective (97%, n = 122/125) and beneficial (74% n = 97/131) for their clients. Many pharmacists reported being ready (60% n = 79/130) and willing (86% n = 111/129) to prescribe PrEP, although over half (62% n = 73/118) cited lack of PrEP knowledge as a barrier. Pharmacists described pharmacies as an appropriate location to prescribe PrEP (72% n = 97/134). Conclusions: Most SC pharmacists surveyed considered PrEP to be effective and beneficial for individuals who frequent their pharmacy and are willing to prescribe this therapy if statewide statutes allow. Many felt that pharmacies are an appropriate location to prescribe PrEP but lack a complete understanding of required protocols to manage these patients. Further investigation into facilitators and barriers of pharmacy-driven PrEP is needed to enhance utilization within communities

Microwave and Millimeter Wave Techniques

Contains research objectives and summary of research on four research projects.Joint Services Electronics Program (Contract DAAB07-74-C-0630)National Science Foundation (Grant GP-40485X)National Science Foundation (Grant MPS73-05043-A01