Antiproton annihilation on light nuclei at very low energies

The recent experimental data obtained by the OBELIX group on $\bar{p}$D and $\bar{p}^4$He total annihilation cross sections are analyzed. The combined analysis of these data with existing antiprotonic atom data allows, for the first time, the imaginary parts of the S-wave scattering lengths for the two nuclei to be extracted. The obtained values are: $Im a^{sc}_0 = [- 0.62 \pm 0.02 ({stat}) \pm 0.04 ({sys})] fm$ for $\bar{p}$D and $Im a^{sc}_0 = [- 0.36\pm 0.03({stat})^{+0.19}_{-0.11}({sys})] fm$ for $\bar{p}^4$He. This analysis indicates an unexpected behaviour of the imaginary part of the $\bar{p}$-nucleus S-wave scattering length as a function of the atomic weight A: $|Im a^{sc}_0|$ ($\bar{p}$p) > $|Im a^{sc}_0|$ ($\bar{p}$D) > $|Im a^{sc}_0|$ ($\bar{p}^4$He).Comment: 13 pages, 5 figure

The {\it ab initio} calculation of spectra of open shell diatomic molecules

The spectra (rotational, rotation-vibrational or electronic) of diatomic molecules due to transitions involving only closed-shell ($^1\Sigma$) electronic states follow very regular, simple patterns and their theoretical analysis is usually straightforward. On the other hand, open-shell electronic states lead to more complicated spectral patterns and, moreover, often appear as a manifold of closely lying electronic states, leading to perturbations with even larger complexity. This is especially true when at least one of the atoms is a transition metal. Traditionally these complex cases have been analysed using approaches based on perturbation theory, with semi-empirical parameters determined by fitting to spectral data. Recently the needs of two rather diverse scientific areas have driven the demand for improved theoretical models of open-shell diatomic systems based on an \emph{ab initio} approach, these areas are ultracold chemistry and the astrophysics of "cool" stars, brown dwarfs and most recently extrasolar planets. However, the complex electronic structure of these molecules combined with the accuracy requirements of high-resolution spectroscopy render such an approach particularly challenging. This review describes recent progress in developing methods for directly solving the effective Schr\"odinger equation for open-shell diatomic molecules, with a focus on molecules containing a transtion metal. It considers four aspects of the problem: 1. The electronic structure problem, 2. Non-perturbative treatments of the curve couplings, 3. The solution of the nuclear motion Schr\"odinger equation, 4. The generation of accurate electric dipole transition intensities. Examples of applications are used to illustrate these issues.Comment: Topical Revie

Journal off Mechanical Design The Application of Curvature Theory to the Trajectory Generation Problem of Robot Manipulators

This paper illustrates a new application of planar curvature theory to the geometric problem of trajectory generation by a two-link manipulator. The theory yields the instantaneous speed ratio, and the rate of change of the speed ratio, which correspond to the geometry of a desired point trajectory. Separate from the purely geometric speed ratio problem (i.e., the coordination problem) is the time based problem of controlling the joint rates in order to move with the specified path variables. Introduction A rigid body, constrained to move in a plane with N independent degrees of freedom, where 1 < N < 3, is known as a planar TV-parameter motion, denoted by M N . This paper discusses the arm-subassembly of a planar manipulator, whose terminal link is a planar M 2 motion. The purpose is to illustrate a new application of classical curvature theory to the problem of trajectory generation by a multi-degree-of-freedom rigid body system, in this case a planar robot manipulator. Previously, curvature theory has been applied to the dimensional synthesis of planar mechanisms. The new application of the theory illustrated here is a problem of motion synthesis by industrial manipulators

World Workshop on Oral Medicine VII : Relative frequency of oral mucosal lesions in children, a scoping review

Objective: To detail a scoping review on the global and regional relative frequencies of oral mucosal disorders in the children based on both clinical studies and those reported from biopsy records. Materials and Methods: A literature search was completed from 1 January 1990 to 31 December 2018 using PubMed and EMBASE. Results: Twenty clinical studies (sample size: 85,976) and 34 studies from biopsy services (40,522 biopsies) were included. Clinically, the most frequent conditions were aphthous ulcerations (1.82%), trauma-associated lesions (1.33%) and herpes simplex virus (HSV)-associated lesions (1.33%). Overall, the most commonly biopsied lesions were mucoceles (17.12%), fibrous lesions (9.06%) and pyogenic granuloma (4.87%). By WHO geographic region, the pooled relative frequencies of the most common oral lesions were similar between regions in both clinical and biopsy studies. Across regions, geographic tongue (migratory glossitis), HSV lesions, fissured tongue and trauma-associated ulcers were the most commonly reported paediatric oral mucosal lesions in clinical studies, while mucoceles, fibrous lesions and pyogenic granuloma were the most commonly biopsied lesions. Conclusions: The scoping review suggests data from the clinical studies and biopsy records shared similarities in the most commonly observed mucosal lesions in children across regions. In addition, the majority of lesions were benign in nature

ExoMol molecular line lists - XXVI::spectra of SH and NS

Line lists for the sulphur-containing molecules SH (the mercapto radical) and NS are computed as part of the ExoMol project. These line lists consider transitions within the $X$ ${}^2\Pi$ ground state for $^{32}$SH, $^{33}$SH, $^{34}$SH and $^{\text{32}}$SD, and $^{14}$N$^{32}$S, $^{14}$N$^{33}$S, $^{14}$N$^{34}$S, $^{14}$N$^{36}$S and $^{15}$N$^{32}$S. Ab initio potential energy (PEC) and spin-orbit coupling (SOC) curves are computed and then improved by fitting to experimentally observed transitions. Fully ab initio dipole moment curves (DMCs) computed at high level of theory are used to produce the final line lists. For SH, our fit gives a root-mean-square (rms) error of 0.03 cm$^{-1}$ between the observed ($v_{\rm max}=4$, $J_{\rm max} = 34.5$) and calculated transitions wavenumbers; this is extrapolated such that all $X$ $^2\Pi$ rotational-vibrational-electronic (rovibronic) bound states are considered. For $^{\text{32}}$SH the resulting line list contains about 81000 transitions and 2300 rovibronic states, considering levels up to $v_{\rm max} = 14$ and $J_{\rm max} = 60.5$. For NS the refinement used a combination of experimentally determined frequencies and energy levels and led to an rms fitting error of 0.002 cm$^{-1}$. Each NS calculated line list includes around 2.8 million transitions and 31000 rovibronic states with a vibrational range up to $v=53$ and rotational range to $J=235.5$, which covers up to 23000 cm$^{-1}$. Both line lists should be complete for temperatures up to 5000 K. Example spectra simulated using this line list are shown and comparisons made to the existing data in the CDMS database. The line lists are available from the CDS (http://cdsarc.u-strasbg.fr) and ExoMol (www.exomol.com) data bases

Urinary markers of intrarenal renin-angiotensin system activity in vivo

Recent interest focuses on urinary renin and angiotensinogen as markers of renal renin-angiotensin system activity. Before concluding that these components are independent markers, we need to exclude that their presence in urine, like that of albumin (a protein of comparable size), is due to (disturbed) glomerular filtration. This review critically discusses their filtration, reabsorption and local release. Given the close correlation between urinary angiotensinogen and albumin in human studies, it concludes that, in humans, urinary angiotensinogen is a filtration barrier damage marker with the same predictive power as urinary albumin. In contrast, in animals, tubular angiotensinogen release may occur, although tubulus-specific knockout studies do not support a functional role for such angiotensinogen. Urinary renin levels, relative to albumin, are >200-fold higher and unrelated to albumin. This may reflect release of renin from the urinary tract, but could also be attributed to activation of filtered, plasma-derived prorenin and/or incomplete tubular reabsorption

Exploring novel arterio-venous graft designs to reduce vascular access failure risk

Although arterio-venous grafts (AVGs) are the second best option as permanent vascular access for hemodialysis, this solution is still affected by a relevant failure rate associated with neointimal hyperplasia (IH), mainly located at the venous anastomosis, where abnormal hemodynamics occurs. In this study we use computational fluid dynamics (CFD) to investigate the impact of six innovative AVG designs on reducing the IH risk at the distal anastomosis in AVGs. Findings from simulations clearly show that using a helical shaped flow divider located in the venous side of the graft could assure a reduced hemodynamic risk of failure at the distal anastomosis, with a clinically irrelevant increase in pressure drop over the graft