Cutworm damage to the Missouri corn crop, 1977-1980

Cover title.Includes bibliographical references

An investigation of liquid crystalline and semiconducting blends for applications in photovoltaics

We investigated a number of novel liquid crystalline semiconductors which have been synthesised in house at the University of Hull. The electrochemical and optical properties of these materials were studied, in order to assess their suitability as donor or acceptor materials for photovoltaic (PV) devices. We investigated the HOMO and LUMO energies of materials with similar chemical structures and hence identified the effect of adding or removing certain molecular groups. Compounds with a benzothiadiazole-thiophene structure were found to be potentially low band gap electron donor materials with perylene based compounds as electron acceptors. Fluorene-thiophene based compounds were also identified as potential electron donors. Charge mobility was studied for several electron donor compounds with similar chemical structures. Donor and acceptor (D/A) blends were investigated and compared to the pure compounds. The Time of Flight (TOF) technique was used to measure mobility. For the pure donor a reduction in mobility is seen when the molecule chain is extended with two additional thiophene groups. The electron mobility of the blends was higher by 2 orders of magnitude than that of the pure acceptor. This provides the blends with balanced charge transport for PV devices.We fabricated and characterised bulk heterojunction PV devices mixing various donor materials with the same perylene acceptor. The highest device efficiency was produced by a fluorene-thiophene structured donor compound. The fill factor (FF) for all devices was poor and this may be attributed to the acceptor material. We investigated the phase transitions of several D/A blends. An improved device efficiency was produced when we annealed within the liquid crystal phase. We investigated the thin film morphology using an atomic force microscope (AFM) and correlated domain size to PV device performance

An Improved Measurement of the Hubble Constant from the Sunyaev-Zeldovich Effect

We present a determination of the Hubble constant from measurements of the Sunyaev-Zeldovich Effect (SZE) in an orientation-unbiased sample of 7 z < 0.1 galaxy clusters. With improved X-ray models and a more accurate 32-GHz calibration, we obtain H_O = 64+14-11 +/- 14_sys km/s/Mpc. for a standard CDM cosmology, or 66+14-11 +/- 15_sys km/s/Mpc for a flat LambdaCDM cosmology. In combination with X-ray cluster measurements and the BBN value for Omega_B, we find Omega_M = 0.32 +/- 0.05.Comment: 5 pp., Accepted for publication in ApJ

Assessing An Economics Programme: Hansen Proficiencies, ePortfolio, and Undergraduate Research

Numerous sources calling for more accountability in higher education are putting increased pressure on many economics departments to develop assessment plans. This paper discusses a set of principles for programmatic assessment gleaned from the assessment literature, while highlighting one US economic department's journey to develop an assessment of student learning outcomes based on Hansen's proficiencies. We explain the curriculum reforms that culminate with independent undergraduate research as suggested by the highest level of Hansen's proficiencies. We describe ePortfolios which showcase student abilities and integrate evidence of student learning across the curriculum. For departments without direct guidance from accreditation boards or other agencies, we put forth a process of forming programmatic assessment in economics.

Solution-processed bilayer photovoltaic devices with nematic liquid crystals

The cross-linking of polymerisable liquid crystalline semiconductors is a promising approach to solution-processable, multilayer, organic photovoltaics. Here we demonstrate an organic bilayer photovoltaic with an insoluble electron-donating layer formed by cross-linking a nematic reactive mesogen. We investigate a range of perylene diimide (PDI) materials, some of which are liquid crystalline, as the overlying electron acceptor layer. We find that carrier mobility of the acceptor materials is enhanced by liquid crystallinity and that mobility limits the performance of photovoltaic devices. © 2013 © 2013 Taylor & Francis

Mass Models and Sunyaev-Zeldovich Effect Predictions for a Flux Limited Sample of 22 Nearby X-Ray Clusters

We define a 90% complete, volume-limited sample of 31 z<0.1 x-ray clusters and present a systematic analysis of public ROSAT PSPC data on 22 of these objects. Our efforts are undertaken in support of the Penn/OVRO SZE survey, and to this end we present predictions for the inverse Compton optical depth towards all 22 of these clusters. We have performed detailed Monte Carlo simulations to understand the effects of the cluster profile uncertainties on the SZE predictions given the OVRO 5.5-meter telescope beam and switching patterns; we find that the profile uncertainties are one of the least significant components of our error budget for SZE-based distance measurements. We also present baryonic masses and baryon mass fractions derived under the assumption of hydrostatic equilibrium for these 22 clusters. The mean baryonic mass fraction within R_500 \sim 500 h^-1 kpc is (7.02 \pm 0.28) x 10^-2 h^-3/2, or (19.8 \pm 0.8) x 10^-2 for h=0.5. We confirm the Allen et al. (1993) claim of an excess absorbing column density towards Abell 478, but do not find similar anomalies in the other 21 clusters in our sample. We also find some evidence for an excess of soft counts in the ROSAT PSPC data. A measurement of H_o using these models and OVRO SZE determinations will be presented in a second paper.Comment: 51 pages, 6 figures included in text. Added comparison of different cosmologies; accepted for publication in Ap

Ejercicio dosis-respuesta de la pendiente V? E / V?CO 2 en mujeres posmenopáusicas en el estudio DREW

Purpose: Being overweight/obese, having hypertension, and being postmenopausal are risk factors for the development of congestive heart failure (CHF). A characteristic of CHF is an abnormal V?E/V?CO2 slope, which is predictive of mortality in patients with CHF. Although the V?E/V?CO2 slope is well established in CHF patients, little is known regarding interventions for 'at-risk' populations. Methods: We examined the V?E/V?CO2 slope in 401 sedentary, overweight, moderately hypertensive women randomized to 6 m of nonexercise (control) or 4 kcal·kg?1·wk?1 (KKW), 8 KKW, or 12 KKW of exercise at an intensity corresponding to 50% of baseline V?O2max. We examined trends in exercise treatment dose versus change in mean V?E/V?CO2 slope using a linear regression model (KKW vs V?E/V?CO2 slope) and a linear mixed model. Results: Regression analysis showed a significant trend for a reduction in the V?E/V?CO2 slope from baseline (mean ± SD: 32.6 ± 6.3; P < 0.004). When expressed as mean change (95% confidence interval (CI)) from baseline, we observed significant reductions in the V?E/V?CO2 slope for the 8-KKW (?1.14; 95% CI, ?1.5 to ?0.2) and 12-KKW (?1.67; 95% CI, ?2.3 to ?0.3) groups. No significant effect was noted for the 4-KKW (?0.4; 95% CI, ?1.2 to 0.15) group. Conclusion: Moderate-intensity aerobic exercise at doses of 8 KKW or greater seems to present an adequate dose of exercise to promote small but significant reductions in the V?E/V?CO2 slope in postmenopausal women who exhibit risk factors associated with the development of CHF

Detection theory for accurate and non-invasive skin cancer diagnosis using dynamic thermal imaging

Skin cancer is the most common cancer in the United States with over 3.5M annual cases. Presently, visual inspection by a dermatologist has good sensitivity (\u3e 90%) but poor specificity (\u3c 10%), especially for melanoma, which leads to a high number of unnecessary biopsies. Here we use dynamic thermal imaging (DTI) to demonstrate a rapid, accurate and non-invasive imaging system for detection of skin cancer. In DTI, the lesion is cooled down and the thermal recovery is recorded using infrared imaging. The thermal recovery curves of the suspected lesions are then utilized in the context of continuous-time detection theory in order to define an optimal statistical decision rule such that the sensitivity of the algorithm is guaranteed to be at a maximum for every prescribed false-alarm probability. The proposed methodology was tested in a pilot study including 140 human subjects demonstrating a sensitivity in excess of 99% for a prescribed specificity in excess of 99% for detection of skin cancer. To the best of our knowledge, this is the highest reported accuracy for any non-invasive skin cancer diagnosis method

Thermodynamics of R-charged Black Holes in AdS(5) From Effective Strings

It is well known that the thermodynamics of certain near-extremal black holes in asymptotically flat space can be lifted to an effective string description created from the intersection of D-branes. In this paper we present evidence that the semiclassical thermodynamics of near-extremal R-charged black holes in AdS(5)xS(5) is described in a similar manner by effective strings created from the intersection of giant gravitons on the S(5). We also present a free fermion description of the supersymmetric limit of the one-charge black hole, and we give a crude catalog of the microstates of the two and three-charge black holes in terms of operators in the dual conformal field theory.Comment: v2: references and typos corrected, 24 pages, latex2