Preferential Orientation Relationships in Ca2_2MnO4_4 Ruddlesden-Popper thin films

A high-throughput investigation of local epitaxy (called combinatorial substrate epitaxy) was carried out on Ca$_2$MnO$_4$ Ruddlesden-Popper thin films of six thicknesses (from 20 to 400 nm), all deposited on isostructural polycrystalline Sr$_2$TiO$_4$ substrates. Electron backscatter diffraction revealed grain-over-grain local epitaxial growth for all films, resulting in a single orientation relationship ($OR$) for each substrate-film grain pair. Two preferred epitaxial $ORs$ accounted for more than 90 \% of all ORs on 300 different microcrystals, based on analyzing 50 grain pairs for each thickness. The unit cell over unit cell $OR$ ([100][001]$_{film}$ $\parallel$ [100][001]$_{substrate}$, or $OR1$) accounted for approximately 30 \% of each film. The $OR$ that accounted for 60 \% of each film ([100][001]$_{film}$ $\parallel$ [100][010]$_{substrate}$, or $OR2$) corresponds to a rotation from $OR1$ by 90$^{\circ}$ about the a-axis. $OR2$ is strongly favored for substrate orientations in the center of the stereographic triangle, and $OR1$ is observed for orientations very close to (001) or to those near the edge connecting (100) and (110). While $OR1$ should be lower in energy, the majority observation of $OR2$ implies kinetic hindrances decrease the frequency of $OR1$. Persistent grain over grain growth and the absence of variations of the $OR$ frequencies with thickness implies that the growth competition is finished within the first few \si{\nano\meter}, and local epitaxy persists thereafter during growth.Comment: 15 pages, 4 figures, Submitted to Journal Applied Physic

Enhanced electroweak penguin amplitude in B-->VV decays

We discuss a novel electromagnetic penguin contribution to the transverse helicity amplitudes in B decays to two vector mesons, which is enhanced by two powers of mB/Lambda relative to the standard penguin amplitudes. This leads to unique polarization signatures in penguin-dominated decay modes such as B-->rho K* similar to polarization effects in the radiative decay B-->K*gamma, and offers new opportunities to probe the magnitude and chirality of flavour-changing neutral current couplings to photons.Comment: 4 pages, 1 figur

Minimizing magnetic fields for precision experiments

An increasing number of measurements in fundamental and applied physics rely on magnetically shielded environments with sub nano-Tesla residual magnetic fields. State of the art magnetically shielded rooms (MSRs) consist of up to seven layers of high permeability materials in combination with highly conductive shields. Proper magnetic equilibration is crucial to obtain such low magnetic fields with small gradients in any MSR. Here we report on a scheme to magnetically equilibrate MSRs with a 10 times reduced duration of the magnetic equilibration sequence and a significantly lower magnetic field with improved homogeneity. For the search of the neutron's electric dipole moment, our finding corresponds to a linear improvement in the systematic reach and a 40 % improvement of the statistical reach of the measurement. However, this versatile procedure can improve the performance of any MSR for any application.Comment: 5 pages, 4 figure

Worries across time and a ge in Germany: Bringing together open- and close-ended questions

We investigate how worries in Germany change across time and age, drawing on both closed-ended questions (which typically list a number of worry items) and open-ended questions answered in text format. We find that relevant world events influence worries. For example, worries about peace peaked in 2003, the year of the Iraq War, with a considerable number of respondents also referring to the Iraq war in their text responses. Furthermore, we found that - controlling for these historical effects - worries about various topics such as health and the general economic situation increase with age. With increasing age, respondents also became more likely to answer the open-ended question. This suggests that the age increases in worries we found are not merely a result of an age-biased choice of worry items, but instead also hold for worries self-generated by the respondents

Worries across time and age in Germany: Bringing together open and close-ended questions

We investigate how worries in Germany change across time and age, drawing on both closed-ended questions (which typically list a number of worry items) and open-ended questions answered in text format. We find that relevant world events influence worries. For example, worries about peace peaked in 2003, the year of the Iraq War, with a considerable number of respondents also referring to the Iraq war in their text responses. Furthermore, we found that - controlling for these historical effects - worries about various topics such as health and the general economic situation increase with age. With increasing age, respondents also became more likely to answer the open-ended question. This suggests that the age increases in worries we found are not merely a result of an age-biased choice of worry items, but instead also hold for worries self-generated by the respondents

In your eyes only? Discrepancies and agreement between self- and other-reports of personality from age 14 to 29

Do others perceive the personality changes that take place between the ages of 14 and 29 in a similar fashion as the aging person him- or herself? This cross-sectional study analyzed age trajectories in self- versus other-reported Big Five personality traits and in self-other agreement in a sample of more than 10,000 individuals from the myPersonality Project. Results for self-reported personality showed maturation effects (increases in extraversion, conscientiousness, openness to experience, and emotional stability), and this pattern was generally also reflected in other-reports, albeit with discrepancies regarding timing and magnitude. Age differences found for extraversion were similar between the self- and other-reports, but the increase found in self-reported conscientiousness was delayed in other-reports, and the curvilinear increase found in self-reported openness was slightly steeper in other-reports. Only emotional stability showed a distinct mismatch with an increase in self-reports, but no significant age effect in other-reports. Both the self- and other-reports of agreeableness showed no significant age trends. The trait correlations between the self- and other-reports increased with age for emotional stability, openness, agreeableness, and conscientiousness; by contrast, agreement regarding extraversion remained stable. The profile correlations confirmed increases in self-other agreement with age. We suggest that these gains in agreement are a further manifestation of maturation. Taken together, our analyses generally show commonalities but also some divergences in age-associated mean level changes between self- and other-reports of the Big Five, as well as an age trend towards increasing self-other agreement

Balanced sensitivity and specificity on unbalanced data using support vector machine re-thresholding

Support vector machine (SVM) classifiers use multivariate patterns to separate two groups by a hyperplane with maximal margin. This strategy tends to obtain good generalisation accuracy on even very high dimensional applications. However, SVMs are not well suited to unbalanced data with very different numbers of cases in each group. In this work we implement a properly cross-validated method for altering the SVM threshold (also known as the bias or cut-point) to re-balance the sensitivity and specificity

Surface and interstitial Ti diffusion at the rutile TiO2(110) surface

Diffusion of Ti through the TiO2 (110) rutile surface plays a key role in the growth and reactivity of TiO2. To understand the fundamental aspects of this important process, we present an analysis of the diffusion of Ti adspecies at the stoichiometric TiO2(110) surface using complementary computational methodologies of density functional theory corrected for on-site Coulomb interactions (DFT+U) and a charge equilibration (QEq) atomistic potential to identify minimum energy pathways. We find that diffusion of Ti from the surface to subsurface (and vice versa) follows an intersticialcy exchange mechanism, involving exchange of surface Ti with the 6-fold coordinated Ti below the bridging oxygen rows. Diffusion in the subsurface between layers also follows an interstitialcy mechanism. The diffusion of Ti is discussed in light of continued attempts to understand the re-oxidation of non-stoichiometric TiO2(110) surfaces