Vertical structures induced by embedded moonlets in Saturn's rings: the gap region

We study the vertical extent of propeller structures in Saturn's rings. Our focus lies on the gap region of the propeller and on non-inclined propeller moonlets. In order to describe the vertical structure of propellers we extend the model of Spahn and Sremcevic (2000) to include the vertical direction. We find that the gravitational interaction of ring particles with the non-inclined moonlet does not induce considerable vertical excursions of ring particles, but causes a considerable thermal motion in the ring plane. We expect ring particle collisions to partly convert the lateral induced thermal motion into vertical excursions of ring particles. For the gap region of the propeller, we calculate gap averaged propeller heights on the order of 0.7 Hill radii, which is of the order of the moonlet radius. In our model the propeller height decreases exponentially until viscous heating and collisional cooling balance. We estimate Hill radii of 370m and 615m for the propellers Earhart and Bleriot. Our model predicts about 120km for the azimuthal extent of the Earhart propeller at Saturn's 2009 equinox, being consistent with values determined from Cassini images

Constrained optimal discriminating designs for Fourier regression models

In this article, the problem of constructing efficient discriminating designs in a Fourier regression model is considered. We propose designs which maximize the efficiency for the estimation of the coefficient corresponding to the highest frequency subject to the constraints that the coefficients of the lower frequencies are estimated with at least some given efficiency. A complete solution is presented using the theory of canonical moments, and for the special case of equal constraints the optimal designs can be found analytically. --Constrained optimal designs,trigonometric regression,D1-optimal designs,Chebyshev polynomials,canonical moments

Future Bloom and Blossom Frost Risk for Malus domestica Considering Climate Model and Impact Model Uncertainties

The future bloom and risk of blossom frosts for Malus domestica were projected using regional climate realizations and phenological (= impact) models. As climate impact projections are susceptible to uncertainties of climate and impact models and model concatenation, the significant horizon of the climate impact signal was analyzed by applying 7 impact models, including two new developments, on 13 climate realizations of the IPCC emission scenario A1B. Advancement of phenophases and a decrease in blossom frost risk for Lower Saxony (Germany) for early and late ripeners was determined by six out of seven phenological models. Single model/single grid point time series of bloom showed significant trends by 2021-2050 compared to 1971-2000, whereas the joint signal of all climate and impact models did not stabilize until 2043. Regarding blossom frost risk, joint projection variability exceeded the projected signal. Thus, blossom frost risk cannot be stated to be lower by the end of the 21st century despite a negative trend. As a consequence it is however unlikely to increase. Uncertainty of temperature, blooming date and blossom frost risk projection reached a minimum at 2078-2087. The projected phenophases advanced by 5.5 d K-1, showing partial compensation of delayed fulfillment of the winter chill requirement and faster completion of the following forcing phase in spring. Finally, phenological model performance was improved by considering the length of day.Lower Saxony Ministry for Science and Culture/KLIF

The effectiveness of supported employment programs : Meta-regression analysis of the global secular trend, 1990-2015

Importance: Supported employment programs aim to re-integrate unemployed people with mental illness into the competitive labour market. While it is known that short-term economic developments like the 2008 recession may have negative consequences on the supported employment effectiveness rates, research into long-term secular trends has not yet been conducted. Objective: The primary objective of the regression analysis was to assess the effectiveness of supported employment programs for clients with any mental disorder over a longer time period. Further objectives were a comparison to prevocational training and the identification of moderating variables. Data sources: We retrieved publications on randomized controlled trials and on routine implementation programs that were included in four recent systematic reviews on supported employment for people with mental illness, plus very recent publications that were identified by a new search. This search was conducted in the following databases: Pubmed, PsycInfo, CINAHL (Cumulative Index on Nursing and Allied Health Literature), and Google Scholar. Study selection: We included any publication that was used in the four meta-analyses plus very recently published studies. The included studies were conducted between 1990 and 2015. Data extraction and synthesis: 80 studies with 14,437 participants were included in the analysis. Data was extracted by one author and cross-checked by the second author. We have conducted univariate and multivariate meta-regressions on the basis of a random-effects meta-analysis of proportions. The best-fitting model was computed by utilizing a statistical model selection procedure. Main Outcome and Measures: The outcome was the competitive employment rate over time. The year of study conduction (1990 to 2015) was regressed on the competitive employment rate. Regression coefficient estimates were computed and graphically displayed. Results: The competitive employment rate of supported employment programs was negatively associated with the study year (estimate -0.0068, CI -0.0114 - -0.0021) and the study period 2008 to 2015 had a larger decline in the competitive employment rate than the period 2000 to 2007. For prevocational training we found no change (estimate 0.0002, CI -0.0059 – 0.0063). Significant moderators were covariates study year/study period, augmented programs and study design (RCT vs. routine implementation). Conclusions and relevance: Results of this meta-regression suggest that supported employment programs have become less effective over time. Supported employment programs need to adapt to a changing labour market that is becoming more challenging to people with mental illness

Ecological restoration as a real-world experiment: designing robust implementation strategies in an urban environment

The concept of real-world experiments is a framework to understand environmental design projects under real world conditions. Contrary to laboratory experiments that are generally thought to exclude the public, real-world experiments involve combinations of social and natural factors. In this paper the theory of real-world experiments is applied to the fieldwork of ecological restoration. The case discussed here is an ecological design process at Montrose Point, a peninsula built on landfill in Lake Michigan on the North Side of Chicago. It illustrates how, in the practice of ecological restoration, the idea of experiment can be understood as being built on processes of recursive learning that include different parts of the wider society and nature. The paper outlines a concept of robust implementation strategies in which public involvement is a pivotal part of a more encompassing activity of ecological practice. This is undertaken to aim at a better understanding of learning processes taking place in natural and social systems

Towards a Theory of Explanation and Prediction for the Formation of Trust in IT Artifacts

In this paper we argue that the predominant trust conceptualization in IS has a major weakness when researching trust in IT artifacts and that a theory of explanation and prediction for the formation of trust in IT artifacts is necessary to face the upcoming challenges. Thus, we motivate a trust conceptualization from the HCI discipline, and develop a formative measurement model for trust in IT artifacts to achieve deeper insights on the formation of trust. The results of our pre-study with 102 undergraduate students suggest that the new conceptualization is valueable for creating the desired insights on the formation of trust in IT artifacts. In an upcoming field experiment with about 250 users we expect to gain more detailed and reliable insights in the formation of trust in IT artifacts allowing us to derive a first theory of explanation and prediction for the formation of trust in IT artifacts

Atomically resolved scanning force studies of vicinal Si(111)

Well-ordered stepped semiconductor surfaces attract intense attention owing to the regular arrangements of their atomic steps that makes them perfect templates for the growth of one- dimensional systems, e.g. nanowires. Here, we report on the atomic structure of the vicinal Si(111) surface with 10 degree miscut investigated by a joint frequency-modulation scanning force microscopy (FM-SFM) and ab initio approach. This popular stepped surface contains 7 x 7-reconstructed terraces oriented along the Si(111) direction, separated by a stepped region. Recently, the atomic structure of this triple step based on scanning tunneling microscopy (STM) images has been subject of debate. Unlike STM, SFM atomic resolution capability arises from chemical bonding of the tip apex with the surface atoms. Thus, for surfaces with a corrugated density of states such as semiconductors, SFM provides complementary information to STM and partially removes the dependency of the topography on the electronic structure. Our FM-SFM images with unprecedented spatial resolution on steps confirm the model based on a (7 7 10) orientation of the surface and reveal structural details of this surface. Two different FM-SFM contrasts together with density functional theory calculations explain the presence of defects, buckling and filling asymmetries on the surface. Our results evidence the important role of charge transfers between adatoms, restatoms, and dimers in the stabilisation of the structure of the vicinal surface