Study of flavour dependencies in leptogenesis

We study the impact of flavours on the efficiency factors and give analytical and numerical results of the baryon asymmetry taking into account the different charged lepton Yukawa contributions and the complete (diagonal and off-diagonal) $L$ to $B-L$ conversion $A$ matrix. With this treatment we update the lower bound on the lightest right-handed neutrino mass.Comment: 13 pages, 11 figures. typos corrected, some formulae modified. 2 figures and discussion adde

The relationship between Intolerance of Uncertainty and conditioned fear acquisition: Evidence from a large sample

Despite being considered a valid model for the etiology of anxiety disorders, the fear conditioning paradigm does not always show clear correlations with anxious personality traits that constitute risk factors for the development of anxiety disorders. This may in part due to error variance and the fact that fear conditioning studies are typically underpowered to investigate inter-individual differences. In the current study, we focus on the relationship between conditioned fear acquisition and Intolerance of Uncertainty (IU). In a re-analysis of a large previous study (N = 120), which was conducted using a healthy student sample and a partial reinforcement procedure (75%) with words as Conditioned Stimuli (CSs), the relationship between IU and several outcome measures (i.e., fear ratings, expectancy ratings, skin conductance responses, and startle responses) during fear acquisition was examined. We find that IU is positively related to fear ratings towards the CS+ (r = 0.29), even when controlling for the shared variance with trait anxiety. Furthermore, we find a subtle relationship between IU and startle responses to the CS− (r = −0.23), though this correlation did not survive correction for the shared variance with trait anxiety. Taken together, we replicate some of the correlations previously reported in the literature. However, we recommend that future studies employ even larger samples and more advanced statistical techniques such as structural equation modelling to investigate the correlations between fear acquisition indices and anxious traits in a fine-grained manner

The relationship between Intolerance of Uncertainty and conditioned fear acquisition: Evidence from a large sample

Despite being considered a valid model for the etiology of anxiety disorders, the fear conditioning paradigm does not always show clear correlations with anxious personality traits that constitute risk factors for the development of anxiety disorders. This may in part due to error variance and the fact that fear conditioning studies are typically underpowered to investigate inter-individual differences. In the current study, we focus on the relationship between conditioned fear acquisition and Intolerance of Uncertainty (IU). In a re-analysis of a large previous study (N = 120), which was conducted using a healthy student sample and a partial reinforcement procedure (75%) with words as Conditioned Stimuli (CSs), the relationship between IU and several outcome measures (i.e., fear ratings, expectancy ratings, skin conductance responses, and startle responses) during fear acquisition was examined. We find that IU is positively related to fear ratings towards the CS+ (r = 0.29), even when controlling for the shared variance with trait anxiety. Furthermore, we find a subtle relationship between IU and startle responses to the CS− (r = −0.23), though this correlation did not survive correction for the shared variance with trait anxiety. Taken together, we replicate some of the correlations previously reported in the literature. However, we recommend that future studies employ even larger samples and more advanced statistical techniques such as structural equation modelling to investigate the correlations between fear acquisition indices and anxious traits in a fine-grained manner

Speed Matters: Relationship between Speed of Eye Movements and Modification of Aversive Autobiographical Memories

Eye movement desensitization and reprocessing (EMDR) is an efficacious treatment for post-traumatic stress disorder. In EMDR, patients recall a distressing memory and simultaneously make eye movements (EM). Both tasks are considered to require limited working memory (WM) resources. Because this leaves fewer resources available for memory retrieval, the memory should become less vivid and less emotional during future recall. In EMDR analogue studies, a standardized procedure has been used, in which participants receive the same dual task manipulation of 1 EM cycle per second (1 Hz). From a WM perspective, the WM taxation of the dual task might be titrated to the WM taxation of the memory image. We hypothesized that highly vivid images are more affected by high WM taxation and less vivid images are more affected by low WM taxation. In study 1, 34 participants performed a reaction time task, and rated image vividness, and difficulty of retrieving an image, during five speeds of EM and no EM. Both a high WM taxing frequency (fast EM; 1.2 Hz) and a low WM taxing frequency (slow EM; 0.8 Hz) were selected. In study 2, 72 participants recalled three highly vivid aversive autobiographical memory images (n = 36) or three less vivid images (n = 36) under each of three conditions: recall + fast EM, recall + slow EM, or recall only. Multi-level modeling revealed a consistent pattern for all outcome measures: recall + fast EM led to less emotional, less vivid and more difficult to retrieve images than recall + slow EM and recall only, and the effects of recall + slow EM felt consistently in between the effects of recall + fast EM and recall only, but only differed significantly from recall + fast EM. Crucially, image vividness did not interact with condition on the decrease of emotionality over time, which was inconsistent with the prediction. Implications for understanding the mechanisms of action in memory modification and directions for future research are discussed

Measuring Slepton Masses and Mixings at the LHC

Flavor physics may help us understand theories beyond the standard model. In the context of supersymmetry, if we can measure the masses and mixings of sleptons and squarks, we may learn something about supersymmetry and supersymmetry breaking. Here we consider a hybrid gauge-gravity supersymmetric model in which the observed masses and mixings of the standard model leptons are explained by a U(1) x U(1) flavor symmetry. In the supersymmetric sector, the charged sleptons have reasonably large flavor mixings, and the lightest is metastable. As a result, supersymmetric events are characterized not by missing energy, but by heavy metastable charged particles. Many supersymmetric events are therefore fully reconstructible, and we can reconstruct most of the charged sleptons by working up the long supersymmetric decay chains. We obtain promising results for both masses and mixings, and conclude that, given a favorable model, precise measurements at the LHC may help shed light not only on new physics, but also on the standard model flavor parameters.Comment: 24 pages; v2: fixed a typo in our computer program that led to some miscalculated branching ratios, various clarifications and minor improvements, conclusions unchanged, published versio

Probing Cation Antisite Disorder in Gd2Ti2O7 Pyrochlore by Site-specific NEXAFS and XPS

Disorder in Gd2Ti2O7 is investigated by near-edge x-ray-absorption fine structure (NEXAFS) and x-ray photoelectron spectroscopy (XPS). NEXAFS shows Ti4+ ions occupy octahedral sites with a tetragonal distortion induced by vacant oxygen sites. O 1s XPS spectra obtained with a charge neutralization system from Gd2Ti2O7(100) and the Gd2Ti2O7 pyrochlore used by Chen et al. [Phys. Rev. Lett. 88, 105901 (2002)], both yielded a single peak, unlike the previous result on the latter that found two peaks. The current results give no evidence for an anisotropic distribution of Ti and O. The extra features reported in the aforementioned communication resulted from charging effects and incomplete surface cleaning. Thus, a result confirming the direct observation of simultaneous cation-anion antisite disordering and lending credence to the split vacancy model has been clarified