Line-dependent veiling in very active T Tauri Stars

The T Tauri stars with active accretion disks show veiled photospheric spectra. This is supposedly due to non-photospheric continuum radiated by hot spots beneath the accretion shocks at stellar surface and/or chromospheric emission lines radiated by the post-shocked gas. The amount of veiling is often considered as a measure of the mass-accretion rate. We analysed high-resolution photospheric spectra of accreting T Tauri stars LkHa 321, V1331 Cyg, and AS 353 A with the aim of clarifying the nature of the line-dependent veiling. Each of these objects shows a highly veiled, strong emission line spectrum and powerful wind features indicating high rates of accretion and mass loss. Equivalent widths of hundreds of weak photospheric lines were measured in the observed spectra and compared with those in synthetic spectra with the same spectral type. We found that the veiling is strongly line-dependent: larger in stronger photospheric lines and weak or absent in the weakest ones. No dependence of veiling on excitation potential within 0 to 5 eV was found. Different physical processes responsible for these unusual veiling effects are discussed in the framework of the magnetospheric accretion model. The observed veiling has two origins: 1) an abnormal structure of stellar atmosphere heated up by the accreting matter, and 2) a non-photospheric continuum radiated by a hot spot with temperature lower than 10000 K. The true level of the veiling continuum can be derived by measuring the weakest photospheric lines with equivalent widths down to $\approx$10 m\AA. A limited spectral resolution and/or low signal-to-noise ratio results in overestimation of the veiling continuum. In the three very active stars, the veiling continuum is a minor contributor to the observed veiling, while the major contribution comes from the line-dependent veiling.Comment: 10 pages, 10 figures. Accepted for publication in Astronomy and Astrophysic

Octahedral Tilt Instability of ReO_3-type Crystals

The octahedron tilt transitions of ABX_3 perovskite-structure materials lead to an anti-polar (or antiferroelectric) arrangement of dipoles, with the low temperature structure having six sublattices polarized along various crystallographic directions. It is shown that an important mechanism driving the transition is long range dipole-dipole forces acting on both displacive and induced parts of the anion dipole. This acts in concert with short range repulsion, allowing a gain of electrostatic (Madelung) energy, both dipole-dipole and charge-charge, because the unit cell shrinks when the hard ionic spheres of the rigid octahedron tilt out of linear alignment.Comment: 4 page with 3 figures included; new version updates references and clarifies the argument

Beyond imagination: Hypnotic visual hallucination induces greater lateralised brain activity than visual mental imagery

Hypnotic suggestions can produce a broad range of perceptual experiences, including hallucinations. Visual hypnotic hallucinations differ in many ways from regular mental images. For example, they are usually experienced as automatic, vivid, and real images, typically compromising the sense of reality. While both hypnotic hallucination and mental imagery are believed to mainly rely on the activation of the visual cortex via top-down mechanisms, it is unknown how they differ in the neural processes they engage. Here we used an adaptation paradigm to test and compare top-down processing between hypnotic hallucination, mental imagery, and visual perception in very highly hypnotisable individuals whose ability to hallucinate was assessed. By measuring the N170/VPP event-related complex and using multivariate decoding analysis, we found that hypnotic hallucination of faces involves greater top-down activation of sensory processing through lateralised neural mechanisms in the right hemisphere compared to mental imagery. Our findings suggest that the neural signatures that distinguish hypnotically hallucinated faces from imagined faces lie in the right brain hemisphere.Fil: Lanfranco, Renzo C.. University of Edinburgh; Reino Unido. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Rivera Rei, Álvaro. Universidad Adolfo Ibañez; ChileFil: Huepe, David. Universidad Adolfo Ibañez; ChileFil: Ibañez, Agustin Mariano. Universidad Adolfo Ibañez; Chile. Universidad de San Andrés. Departamento de Matemáticas y Ciencias; Argentina. University of California; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Canales Johnson, Andrés. University of Cambridge; Estados Unidos. Universidad Catolica de Maule; Chil

Clinical Experience and Sexual Function Outcome of Patients With Priapism Treated With Penile Cavernosal-Dorsal Vein Shunt Using Saphenous Vein Graft

OBJECTIVES To assess the outcome of new penile cavernosal-dorsal vein shunt using a saphenous vein graft. Traditional surgeries for priapism have high failure rate and subsequent impotence. METHODS We reviewed the medical records of, and administered a questionnaire and the International Index of Erectile Function to, 16 consecutive patients with priapism who had treated with the penile cavernosal-dorsal vein shunt from 1997 to 2007. Their age was 15-65 years. The duration of ischemic priapism was 32 hours to 8 days. Ten patients had previously undergone shunt surgery by other urologists. Of the 16 patients, 5 returned the questionnaires. RESULTS Priapism resolved or was improved after surgery in all 16 patients. One patient was lost to follow-up. One pediatric patient was excluded from the analysis. One patient with nonischemic priapism continued to have sexual intercourse. Of the 13 adult patients with ischemic priapism and follow-up for ≤ 6.5 years, 3 patients had no erection, 1 had very little erection, and 9 (69%) had erection. Of the 9 patients with erections possible, six had had sexual intercourse (International Index of Erectile Function score 32-70) and 3 had not; 1 had a mental disorder, 1 was in prison, and for 1, the reason was unknown. After surgery, color Doppler ultrasound studies showed a patent shunt in all patients and restoration of cavernosal arterial flow in 12 of 13 patients studied. CONCLUSIONS A penile cavernosal-dorsal shunt appears effective for priapism. It resulted in priapism resolution even in patients who had experienced a previous failed cavernosal-glandular shunt or cavernosalspongiosal shunt, with a high rate of sexual function preservation

CAMsterdam at SemEval-2019 task 6: Neural and graph-based feature extraction for the identification of offensive tweets

We describe the CAMsterdam team entry to the SemEval-2019 Shared Task 6 on offen-sive language identification in Twitter data.Our proposed model learns to extract tex-tual features using a multi-layer recurrent net-work, and then performs text classification us-ing gradient-boosted decision trees (GBDT). A self-attention architecture enables the model to focus on the most relevant areas in the text.We additionally learn globally optimised em-beddings for hashtags using node2vec, which are given as additional tweet features to the GBDT classifier.Our best model obtains78.79% macro F1-score on detecting offensive language (subtask A), 66.32% on categorising offence types (targeted/untargeted; subtask B),and 55.36% on identifying the target of of-fence (subtask C)

Gender and sex independently associate with common somatic symptoms and lifetime prevalence of chronic disease

Contains fulltext : 225526.pdf (Publisher’s version ) (Open Access)Sex and gender influence health differently. Associations between sex and health have been extensively studied, but gender (i.e. psychosocial sex) has been largely neglected, partly due to the absence of gender measures in cohort studies. Therefore, our objective was to test the unique associations of gender and sex with common somatic symptoms and chronic diseases, using a gender index created from existing cohort data. We applied LASSO logistic regression to identify, out of 153 unique variables, psychosocial variables that were predictive of sex (i.e. gender-related) in the Dutch LifeLines Cohort Study. These psychosocial variables covered gender roles and institutionalized gender. Using the estimated coefficients, gender indexes were calculated for each adult participant in the study (n = 152,728; 58.5% female; mean age 44.6 (13.1) years). We applied multiple ordinal and logistic regression to test the unique associations of the gender index and sex, and their interactions, with common somatic symptoms assessed by the SCL-90 SOM and self-reported lifetime prevalence of chronic diseases, respectively. We found that in 10.1% of the participants the gender index was not in line with participants' sex: 12.5% of men and 8.4% of women showed a discrepancy between gender index and sex. Feminine gender characteristics are associated with increased common somatic symptoms and chronic diseases, especially in men. Female sex is associated with a higher common somatic symptom burden, but not with a higher prevalence of chronic diseases. The study shows that gender and sex uniquely impact health, and should be considered in epidemiological studies. Our methodology shows that consideration of gender measures in studies is necessary and feasible, based on data generally present in cohort studies

Density Functional Study of Cubic to Rhombohedral Transition in α\alpha-AlF3_3

Under heating, $\alpha$-AlF$_3$ undergoes a structural phase transition from rhombohedral to cubic at temperature $T$ around 730 K. The density functional method is used to examine the $T$=0 energy surface in the structural parameter space, and finds the minimum in good agreement with the observed rhombohedral structure. The energy surface and electronic wave-functions at the minimum are then used to calculate properties including density of states, $\Gamma$-point phonon modes, and the dielectric function. The dipole formed at each fluorine ion in the low temperature phase is also calculated, and is used in a classical electrostatic picture to examine possible antiferroelectric aspects of this phase transition.Comment: A 6-page manuscript with 4 figures and 4 table