Femtosecond spectroscopy of the first events of the photochemical cycle in bacteriorhodopsin

The first steps in the photochemistry of bacteriorhodopsin (BR) are investigated with light pulses of 160 fs duration. Four samples are studied: (i) the purple membrane, (ii) deuterated purple membrane, (iii) BR trimers and (iv) BR monomers. In all samples the first intermediate J is formed within 430±50 fs. No isotope effect is observed in the formation of J upon deuteration, in contrast to previous reports with much higher excitation energies. Thus proton movement to or from the retinal Schiff's base is not relevant during the first step. Comparing the data for trimeric and monomeric BR suggests an upper limit of 50 fs for the transfer of excitation energy from the excitonically coupled trimer to a single retinal chromophore

Web Sites as a Dialogic Tool for Charitable Fundraising NPOs: a comparative study

Non-profit organizations (NPOs), which often dispose of a limited budget, can employ their Web sites strategically to communicate with important stakeholders. However, little research, especially in Europe, has been done so far exploring how NPOs are actually taking advantage of this. This study analyzes how charitable fundraising NPOs in Germany and Switzerland employ their Web sites for dialogic communication with donors and media. Results indicate that NPOs provide well-designed Web sites, yet, fail to engage publics in dialogue. New trends, such as Web 2.0, are still hardly taken into account. Whereas donor publics are often addressed, media are often neglected

Marketing Timber from the Private Woodland

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Modeling the influence of climate and management practices on water quality in Goodwater Creek experimental watershed

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on August 21, 2007)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2006.Dissertations, Academic -- University of Missouri--Columbia -- Biological engineering.The objective of this study was to determine relationships among weather, runoff, water quality, and best management practice (BMP) implementation in reducing atrazine losses in the 7,250-ha Goodwater Creek Experimental Watershed in NE Missouri's Audrain and Boone Counties. Data were collected from 1993 through 2003. Regressions were conducted among water quality indicators, climatic variables, and the change in area protected by BMPs. Results showed significant decreases in atrazine concentrations for June and the combined months of April, May, and June. Covariate analysis of the effect of BMP protected area on atrazine concentrations showed that the time period analyzed was important. Inputs were developed for the Soil and Water Assessment Tool (SWAT) program. The SWAT model was able to simulate decreased atrazine concentrations with 4.5% of the watershed protected by grassed waterways. Changes in the amount of land in conventional, conservation, and no-till tillage systems also affected the simulated atrazine concentrations

Optical picosecond studies of bacteriorhodopsin containing a sterically fixed retinal

The photochemical behaviour of an analogous bacteriorhodopsin (9,12-Ph-BR) which contains the sterically fixed 9,12-phenylretinal has been investigated with picosecond spectroscopy. The following results have been obtained. No ground-state intermediate photoproduct is found in agreement with the previous observation that 9,12-Ph-BR does not exhibit proton pumping under illumination. The excited singlet state has a lifetime of τS = 10 ± 2 ps. This lifetime agrees favourably with the value calculated from the radiative lifetime τrad = 6.2 ns and the fluorescence quantum efficiency of 1.2·10−3. Excited-state absorption occurs which results in fluorescence in the ultraviolet region. These various observations differ drastically from the corresponding findings on bacteriorhodopsin. Most important for an understanding of the differences is the fact that 9,12-phenylretinal does not isomerize in the protein's binding site in contrast to retinal. Our data therefore suggest that the formation of the intermediate K observed in bacteriorhodopsin is accompanied by the all-trans to 13-cis isomerization

Electronic structure and electric-field gradients analysis in CeIn3CeIn_3

Electric field gradients (EFG's) were calculated for the $CeIn_3$ compound at both $^{115}In$ and $^{140}Ce$ sites. The calculations were performed within the density functional theory (DFT) using the augmented plane waves plus local orbital (APW+lo) method employing the so-called LDA+U scheme. The $CeIn_3$ compound were treated as nonmagnetic, ferromagnetic, and antiferromagnetic cases. Our result shows that the calculated EFG's are dominated at the $^{140}Ce$ site by the Ce-4f states. An approximately linear relation is intuited between the main component of the EFG's and total density of states (DOS) at Fermi level. The EFG's from our LDA+U calculations are in better agreement with experiment than previous EFG results, where appropriate correlations had not been taken into account among 4f-electrons. Our result indicates that correlations among 4f-electrons play an important role in this compound and must be taken into account

Media governance and corporate social responsibility of media organizations: an international comparison

Media companies are increasingly becoming aware of the importance of their reputation. In order to legitimate themselves, they are starting to present themselves as ‘good corporate citizens’ by engaging in media governance and corporate social responsibility (CSR) activities. The communication of those activities is crucial for the building of reputation. However, to date, no comprehensive studies have been conducted to evaluate the communication of media governance and CSR activities of media organizations. This study aims to fill this gap and examined websites and reports of selected media organizations in Germany, Italy, France, Austria, and Switzerland. Results indicate that public service media organizations communicate proportionally more on media governance than private media organizations, which may be due to the fact that public service media organizations feel more accountable to the public as they have a public service obligation. Concerning the communication of their CSR activities, media organizations focus on society-oriented measures

The 5f localization/delocalization in square and hexagonal americium monolayers: A FP-LAPW electronic structure study

The electronic and geometrical properties of bulk americium and square and hexagonal americium monolayers have been studied with the full-potential linearized augmented plane wave (FP-LAPW) method. The effects of several common approximations are examined: (1) non-spin polarization (NSP) vs. spin polarization (SP); (2) scalar-relativity (no spin-orbit coupling (NSO)) vs. full-relativity (i.e., with spin-orbit (SO) coupling included); (3) local-density approximation (LDA) vs. generalized-gradient approximation (GGA). Our results indicate that both spin polarization and spin orbit coupling play important roles in determining the geometrical and electronic properties of americium bulk and monolayers. A compression of both americium square and hexagonal monolayers compared to the americium bulk is also observed. In general, the LDA is found to underestimate the equilibrium lattice constant and give a larger total energy compared to the GGA calculations. While spin orbit coupling shows a similar effect on both square and hexagonal monolayer calculations regardless of the model, GGA versus LDA, an unusual spin polarization effect on both square and hexagonal monolayers is found in the LDA results as compared with the GGA results. The 5f delocalization transition of americium is employed to explain our observed unusual spin polarization effect. In addition, our results at the LDA level of theory indicate a possible 5f delocalization could happen in the americium surface within the same Am II (fcc crystal structure) phase, unlike the usually reported americium 5f delocalization which is associated with crystal structure change. The similarities and dissimilarities between the properties of an Am monolayer and a Pu monolayer are discussed in detail.Comment: 22 pages, 8 figure

BoltzTraP. A code for calculating band-structure dependent quantities

A program for calculating the semi-classic transport coefficients is described. It is based on a smoothed Fourier interpolation of the bands. From this analytical representation we calculate the derivatives necessary for the transport distributions. The method is compared to earlier calculations, which in principle should be exact within Boltzmann theory, and a very convincing agreement is found