Self-pollen interference is absent in wild radish (Raphanus raphanistrum, Brassicaceae), a species with sporophytic self-incompatibility

This is the publisher's version. It can also be found here:http://www.amjbot.org/content/94/5/896Explaining the diversity of mating systems and floral forms in flowering plants is a long-standing concern of evolutionary biologists. One topic of interest is the conditions under which self-pollination can interfere with seed set for flowering plants with a self-incompatibility system. We investigated the effect of self-pollen interference for wild radish, Raphanus raphanistrum, which has sporophytic self-incompatibility. We performed pollinations and determined seed set for plants grown in the greenhouse, using pollen mixtures representing either self- with outcross-pollen or outcross-pollen alone. Stigmas were collected for a subset of pollinated flowers to determine the number of pollen grains applied. Average seed set for the self/cross (5.13 seeds/pollination) and cross treatments (5.09 seeds/pollination) did not differ significantly. Stigmatic pollen loads averaged around 700 grains, an amount close to observed natural pollen loads on R. raphanistrum. We concluded that for R. raphanistrum in natural populations, self-pollen is unlikely to interfere with outcross-pollen success. This study is the first to investigate effects of self-pollen interference on seed set for a homomorphic species with sporophytic self-incompatibility where rejection occurs at the stigmatic surface

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

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

Genetic factors associated with mating system cause a partial reproductive barrier between two parapatric species of Leavenworthia (Brassicaceae)

This is the publisher's version. It can also be found here: http://www.amjbot.org/content/97/3/412Reproductive barriers play a major role in the origin and maintenance of biodiversity by restricting gene flow between species. Although both pre- and postzygotic barriers often isolate species, prezygotic barriers are thought to contribute more to reproductive isolation. We investigated possible reproductive barriers between Leavenworthia alabamica and L. crassa, parapatric species with high morphological and ecological similarity and the ability to hybridize. Using greenhouse and field experiments, we tested for habitat isolation and genetic incompatibilities. From controlled crosses, we identified unilateral incompatibility (a partial prezygotic barrier associated with the self-incompatibility system), but no evidence of other genetic incompatibilities. We found a small reduction in pollen viability of F1 hybrids and early germination of F1, F2, and BC hybrids relative to L. alabamica and L. crassa in a common garden experiment, but the effect on fitness was not tested. Field studies of hybrid pollen viability and germination are needed to determine if they contribute to reproductive isolation. In a reciprocal transplant, we found no evidence of habitat isolation or reduced hybrid survival (from seedling to adult stage) or reproduction. These data suggest unilateral incompatibility partially reproductively isolates L. alabamica and L. crassa, but no other reproductive barriers could be detected

Performance of Improved Ground During the 2001 Nisqually Earthquake

Several sites in the Seattle area of Washington incorporated ground improvement as liquefaction mitigation or to increase bearing capacity prior to the 2001 Nisqually earthquake. Facilities with improved ground include an earthen dam, a waste repository embankment, lightweight and large plan structures, and bridge columns and approaches. The sites were improved using vibro-replacement stone columns, vibroflotation, or deep dynamic compaction. All sites performed extremely well, despite evidence of liquefaction and minor structural damage nearby. In this paper, 10 sites are summarized, and the performance of three sites located near liquefied or damaged areas will be described in detail. The detailed sites include a large plan commercial property on liquefiable fill improved to a limited lateral extent, a lightweight tilt-up structure located near evidence of liquefaction at King County International Airport, and an earthen dam with its toe retrofitted using vibro-replacement stone columns

Early picosecond events in the photo cycle of Bacteriorhodopsin

The primary processes of the photochemical cycle of light-adapted bacteriorhodopsin (BR) were studied by various experimental techniques with a time resolution of 5 × 10-13 s. The following results were obtained. (a) After optical excitation the first excited singlet state S1 of bacteriorhodopsin is observed via its fluorescence and absorption properties. The population of the excited singlet state decays with a lifetime τ1 of ~0.7 ps (430 ± 50 fs) (52). (b) With the same time constant the first ground-state intermediate J builds up. Its absorption spectrum is red-shifted relative to the spectrum of BR by ~30 nm. (c) The second photoproduct K, which appears with a time constant of τ2 = 5 ps shows a red-shift of 20 nm, relative to the peak of BR. Its absorption remains constant for the observation time of 300 ps. (d) Upon suspending bacteriorhodopsin in D2O and deuterating the retinal Schiff base at its nitrogen (lysine 216), the same photoproducts J and K are observed. The relaxation time constants τ1 and τ2 remain unchanged upon deuteration within the experimental accuracy of 20%

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

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