Public Lending Right: The American Author's Viewpoint

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Spin and spatial dynamics in electron-impact scattering off S-wave He using R-matrix with Time-Dependence theory

R-matrix with time-dependence theory is applied to electron-impact ionisation processes for He in the S-wave model. Cross sections for electron-impact excitation, ionisation and ionisation with excitation for impact energies between 25 and 225 eV are in excellent agreement with benchmark cross sections. Ultra-fast dynamics induced by a scattering event is observed through time-dependent signatures associated with autoionisation from doubly excited states. Further insight into dynamics can be obtained through examination of the spin components of the time-dependent wavefunction.Comment: 6 pages, 5 figure

Double Ionisation in R-Matrix Theory Using a 2-electron Outer Region

We have developed a two-electron outer region for use within R-matrix theory to describe double ionisation processes. The capability of this method is demonstrated for single-photon double ionisation of He in the photon energy region between 80 eV to 180 eV. The cross sections are in agreement with established data. The extended RMT method also provides information on higher-order processes, as demonstrated by the identification of signatures for sequential double ionisation processes involving an intermediate He$^{+}$ state with $n=2$.Comment: 5 pages, 4 figure

Core-Level Spectroscopy of Photoactive Materials

In order for next generation solar technologies to continue to improve, detailed chemical and electronic information is essential. Core-level spectroscopies, such as X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and resonant photoelectron and Auger spectroscopies are capable of providing this information. These techniques have been used for decades across many systems but are limited to ultra-high vacuum pressures, however more recently measurements at ambient pressures have become possible. The thesis presented herein applies core-level spectroscopies to two systems: dye sensitised solar cells and solar water splitting. In the former, ultra-high vacuum core-level spectroscopies are employed to probe the chemical and electronic coupling between the dye and substrate. For the latter, ambient-pressure X-ray photoelectron spectroscopy allows the oxidation of a potential solar water splitting catalyst to be monitored. To begin, a relatively simple dye, C343, is investigated on different mesoporous substrates; TiO2 and SrTiO3. These samples were prepared ex-situ and, in the case of TiO2, compared to samples prepared by thermally evaporating C343 in-situ. By also comparing to a multilayer of dye, a detailed description of how the dye is bonded to the substrates is presented and the density of states probed. To assist in the dye’s analysis, a similar dye, C334, is also investigated. Next, core-level spectroscopies are applied to a more complicated dye-TiO2 system involving the well-known dye N3 as the sensitiser. Here, the bonding to the surface is confirmed by X-ray photoelectron spectroscopy. In addition, resonant Auger electron spectroscopy is used to quantify both charge delocalisation within the molecule as well as injection into the substrate conduction band. Hard X-rays are used to study excitations from both the S 1s and Ru 2p3/2 core levels. The effect of the substrate is seen on the calculated charge transfer dynamics, and a picture of charge transfer from the thiocyanate ligand discussed. Two further dye-TiO2 systems are investigated using core level spectroscopies; RuP and RuC. These dyes are qualitatively very similar, differing only in their anchoring group. Resonant Auger electron spectroscopy is again employed, alongside resonant photoelectron spectroscopy, to quantify the charge injection and delocalisation times of both dyes. In this context, the measurements are a probe of how the anchoring group influences the injection dynamics of dye-sensitised solar cells. It is found that both dyes are capable of sub- femtosecond charge injection in the Ru 2p3/2 excited regime, however that RuP is favoured for its slower relaxation. Finally, ambient pressure X-ray photoelectron spectroscopy is used to study the oxidation chemistry of a prospective solar water splitting catalyst: TiSi2. Both powder and thin film samples are investigated, where the latter were employed in order to remove the natural oxidation caused by air. To do so, different passivation layers were investigated to preserve the TiSi2 layer. From the measurements, it is suggested that the reported catalytic activity of TiSi2 is related to the growth of a sub- stoichiometric silicon oxide, and the minimisation of SiO2 at the TiSi2 surface

Aggregation of the Southern Pine Beetle in Response to Attractive Host Trees

Dendroctonus frontalis Zimmerman were attracted to shortleaf pines, Pinus echinata MilL, using infested shortleaf pine bolts. Response was monitored during the ensuing mass attack period by the use of sticky traps suspended along the tree boles. Uninfested host materials or host materials containing only male beetles did not elicit mass attack of trees. Female beetles either alone or in combination with males, usually stimulated mass attack within 24 h. Traps at 3-4 m above the ground caught the greatest number (26.7%) of beetles. Trap catches peaked on the 3rd day of attack and declined rapidly thereafter. Daily flight activity was greatest at ca. 1700 h during the summer. Male beetles outnumbered females by a ratio of 1:0.86. The sex ratio of trapped beetles varied consistently both diurnally and over the mass attack period

Core-Level Spectroscopy of Photoactive Materials

In order for next generation solar technologies to continue to improve, detailed chemical and electronic information is essential. Core-level spectroscopies, such as X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and resonant photoelectron and Auger spectroscopies are capable of providing this information. These techniques have been used for decades across many systems but are limited to ultra-high vacuum pressures, however more recently measurements at ambient pressures have become possible. The thesis presented herein applies core-level spectroscopies to two systems: dye sensitised solar cells and solar water splitting. In the former, ultra-high vacuum core-level spectroscopies are employed to probe the chemical and electronic coupling between the dye and substrate. For the latter, ambient-pressure X-ray photoelectron spectroscopy allows the oxidation of a potential solar water splitting catalyst to be monitored. To begin, a relatively simple dye, C343, is investigated on different mesoporous substrates; TiO2 and SrTiO3. These samples were prepared ex-situ and, in the case of TiO2, compared to samples prepared by thermally evaporating C343 in-situ. By also comparing to a multilayer of dye, a detailed description of how the dye is bonded to the substrates is presented and the density of states probed. To assist in the dye’s analysis, a similar dye, C334, is also investigated. Next, core-level spectroscopies are applied to a more complicated dye-TiO2 system involving the well-known dye N3 as the sensitiser. Here, the bonding to the surface is confirmed by X-ray photoelectron spectroscopy. In addition, resonant Auger electron spectroscopy is used to quantify both charge delocalisation within the molecule as well as injection into the substrate conduction band. Hard X-rays are used to study excitations from both the S 1s and Ru 2p3/2 core levels. The effect of the substrate is seen on the calculated charge transfer dynamics, and a picture of charge transfer from the thiocyanate ligand discussed. Two further dye-TiO2 systems are investigated using core level spectroscopies; RuP and RuC. These dyes are qualitatively very similar, differing only in their anchoring group. Resonant Auger electron spectroscopy is again employed, alongside resonant photoelectron spectroscopy, to quantify the charge injection and delocalisation times of both dyes. In this context, the measurements are a probe of how the anchoring group influences the injection dynamics of dye-sensitised solar cells. It is found that both dyes are capable of sub- femtosecond charge injection in the Ru 2p3/2 excited regime, however that RuP is favoured for its slower relaxation. Finally, ambient pressure X-ray photoelectron spectroscopy is used to study the oxidation chemistry of a prospective solar water splitting catalyst: TiSi2. Both powder and thin film samples are investigated, where the latter were employed in order to remove the natural oxidation caused by air. To do so, different passivation layers were investigated to preserve the TiSi2 layer. From the measurements, it is suggested that the reported catalytic activity of TiSi2 is related to the growth of a sub- stoichiometric silicon oxide, and the minimisation of SiO2 at the TiSi2 surface

Field Response of the Southern Pine Beetle to Behavioral Chemicals

Field tests were conducted in East Texas in 1973-77 to evaluate the influence of 7 behavioral chemicals on the flight and landing behavior of the southern pine beetle, Dendroctonus frontalis Zimmerman. A mixture of frontalin plus host tree volatiles attracted flying beetles within an infestation. Trans-verbenol synergized the activity of frontalin and substituted for host tree volatiles, expinene and loblolly turpentine. Verbenone in a 1: 1 ratio with frontalin did not significantly affect trap catch. At higher concentrations of verbenone, trap catch was significantly reduced. Endobrevicomin inhibited trap catch when added to an attractant-baited trap. Exo-brevicomin showed no inhibitory effect. Traps with a 1:4 mixture of endo-brevicomin and verbenone plus an attractant caught significantly fewer beetles than traps with the attractant plus either one of the inhibitors

Barriers to the Effective Implementation of Immunization Information Systems in a Private Provider Setting

One of the goals of Healthy People 2010 is to increase the proportion of children less than 6 years of age with two or more vaccinations recorded in a fully operational population-based immunization information system to 95%. In 2008, we piloted the Nevada web-based immunization information system (WEBIZ) in a large private pediatric clinic in north-west Las Vegas. Our objectives were: (1) to determine compliance with the recommendation that all vaccine providers report immunization activities to the WEBIZ without a state mandate and (2) to determine perceived barriers to compliance and suggestions on how to overcome expressed barriers. We documented the number of newly created and updated immunization records as outcome measures of compliance following initial training, ongoing technical support and feedback to the clinic staff on the use of WEBIZ. We found low compliance with the recommendation to document immunization activities and clinic staffs were more likely to document immunization activities when there is an established record in WEBIZ compared to when a new record had to be created by the staff. Our survey of participating clinic staff, identified time to create new records as the most common reported barrier to compliance with recommendation. We concluded that without a state mandate, compliance with the recommendation would remain low and that documentation of hepatitis B birth dose in WEBIZ, thus creating an initial record, could potentially reduce barriers to compliance with recommendation to document immunization activity in WEBIZ

Duration of Posttraumatic Amnesia Predicts Neuropsychological and Global Outcome in Complicated Mild Traumatic Brain Injury.

OBJECTIVES: Examine the effects of posttraumatic amnesia (PTA) duration on neuropsychological and global recovery from 1 to 6 months after complicated mild traumatic brain injury (cmTBI). PARTICIPANTS: A total of 330 persons with cmTBI defined as Glasgow Coma Scale score of 13 to 15 in emergency department, with well-defined abnormalities on neuroimaging. METHODS: Enrollment within 24 hours of injury with follow-up at 1, 3, and 6 months. MEASURES: Glasgow Outcome Scale-Extended, California Verbal Learning Test II, and Controlled Oral Word Association Test. Duration of PTA was retrospectively measured with structured interview at 30 days postinjury. RESULTS: Despite all having a Glasgow Coma Scale Score of 13 to 15, a quarter of the sample had a PTA duration of greater than 7 days; half had PTA duration of 1 of 7 days. Both cognitive performance and Extended Glasgow Outcome Scale outcomes were strongly associated with time since injury and PTA duration, with those with PTA duration of greater than 1 week showing residual moderate disability at 6-month assessment. CONCLUSIONS: Findings reinforce importance of careful measurement of duration of PTA to refine outcome prediction and allocation of resources to those with cmTBI. Future research would benefit from standardization in computed tomographic criteria and use of severity indices beyond Glasgow Coma Scale to characterize cmTBI