Notations and conventions in molecular spectroscopy: part 2. Symmetry notation

The field of Molecular Spectroscopy was surveyed in order to determine a set of conventions and symbols which are in common use in the spectroscopic literature. This document, which is Part 2 in a series, establishes the notations and conventions used for the description of symmetry in rigid molecules, using the Schoenflies notation. It deals firstly with the symmetry operators of the molecular point groups (also drawing attention to the difference between symmetry operators and elements). The conventions and notations of the molecular point groups are then established, followed by those of the representations of these groups as used in molecular spectroscopy. Further parts will follow, dealing inter alia with permutation and permutation-inversion symmetry notation, vibration-rotation spectroscopy and electronic spectroscopy

Notations and conventions in molecular spectroscopy: part 1. General spectroscopic notation

The field of Molecular Spectroscopy was surveyed in order to determine a set of conventions and symbols which are in common use in the spectroscopic literature. This document, which is Part I in a series, establishes the notations and conventions used for general spectroscopic notations and deals with quantum mechanics, quantum numbers (vibrational states, angular momentum and energy levels), spectroscopic transitions, and miscellaneous notations (e.g. spectroscopic terms). Further parts will follow, dealing inter alia with symmetry notation, permutation and permutation-inversion symmetry notation, vibration-rotation spectroscopy and electronic spectroscopy

β-Alanine Supplementation Has No Effect on Rowing Performance in College Age Athletes

Please view abstract in the attached PDF file

Dust Dynamics in Compressible MHD Turbulence

We calculate the relative grain-grain motions arising from interstellar magnetohydrodynamic (MHD) turbulence. The MHD turbulence includes both fluid motions and magnetic fluctuations. While the fluid motions accelerate grains through hydro-drag, the electromagnetic fluctuations accelerate grains through resonant interactions. We consider both incompressive (Alfv\'{e}n) and compressive (fast and slow) MHD modes and use descriptions of MHD turbulence obtained in Cho & Lazarian (2002). Calculations of grain relative motion are made for realistic grain charging and interstellar turbulence that is consistent with the velocity dispersions observed in diffuse gas, including cutoff of the turbulence from various damping processes. We show that fast modes dominate grain acceleration, and can drive grains to supersonic velocities. Grains are also scattered by gyroresonance interactions, but the scattering is less important than acceleration for grains moving with sub-Alfv\'{e}nic velocities. Since the grains are preferentially accelerated with large pitch angles, the supersonic grains will be aligned with long axes perpendicular to the magnetic field. We compare grain velocities arising from MHD turbulence with those arising from photoelectric emission, radiation pressure and H$_{2}$ thrust. We show that for typical interstellar conditions turbulence should prevent these mechanisms from segregating small and large grains. Finally, gyroresonant acceleration is bound to preaccelerate grains that are further accelerated in shocks. Grain-grain collisions in the shock may then contribute to the overabundance of refractory elements in the composition of galactic cosmic rays.Comment: 15 pages, 17 figure

Long-Term Consumption of 10 Food Groups and Cardiovascular Mortality: A Systematic Review and Dose Response Meta-Analysis of Prospective Cohort Studies

A large body of evidence exists on diet and cardiovascular mortality, but limited studies have investigated the long-term intake of food groups, which may have cumulative effects on cardiovascular health in the long term. This review therefore evaluated the relationship between the long-term consumption of 10 food groups and cardiovascular mortality. We conducted a systematic search in Medline, Embase, Scopus, CINAHL, and Web of Science till January 2022. Of the 5318 studies initially identified, 22 studies with a total of 70,273 participants with cardiovascular mortality were included. Summary HRs and 95% CIs were estimated using a random effects model. We found that a long-term high intake of whole grains (HR: 0.87; 95% CI: 0.80, 0.95; P = 0.001), fruits and vegetables (HR: 0.72; 95% CI: 0.61, 0.85; P < 0.0001), and nuts (HR: 0.73; 95% CI: 0.66, 0.81; P < 0.00001) significantly reduced cardiovascular mortality. Each 10-gram increase in whole grain consumption per day was associated with a 4% reduction in the risk of cardiovascular mortality, whereas each 10-gram increase in red/processed meat consumption per day was associated with a 1.8% increase in the risk of cardiovascular mortality. Compared with the lowest intake category, red/processed meat consumption in the highest category was associated with an increased risk of cardiovascular mortality (HR: 1.23; 95% CI: 1.09, 1.39; P = 0.006). High intake of dairy products (HR: 1.11; 95% CI: 0.92, 1.34; P = 0.28), and legumes (HR: 0.86; 95% CI: 0.53, 1.38; P = 0.53) were not associated with cardiovascular mortality. However, in the dose-response analysis, each 10-gram increase in legume intake per week was associated with a 0.5% reduction in cardiovascular mortality. We conclude that the long-term high intake of whole grains, vegetables, fruits, nuts, and a low intake of red/processed meat are associated with reduced cardiovascular mortality. More data on the long-term effects of legumes on cardiovascular mortality are encouraged. This study was registered at PROSPERO as CRD42020214679

Blackbody-radiation-assisted molecular laser cooling

The translational motion of molecular ions can be effectively cooled sympathetically to temperatures below 100 mK in ion traps through Coulomb interactions with laser-cooled atomic ions. The distribution of internal rovibrational states, however, gets in thermal equilibrium with the typically much higher temperature of the environment within tens of seconds. We consider a concept for rotational cooling of such internally hot, but translationally cold heteronuclear diatomic molecular ions. The scheme relies on a combination of optical pumping from a few specific rotational levels into a ``dark state'' with redistribution of rotational populations mediated by blackbody radiation.Comment: 4 pages, 5 figure

On the Identification of High Mass Star Forming Regions using IRAS: Contamination by Low-Mass Protostars

We present the results of a survey of a small sample (14) of low-mass protostars (L_IR < 10^3 Lsun) for 6.7 GHz methanol maser emission performed using the ATNF Parkes radio telescope. No new masers were discovered. We find that the lower luminosity limit for maser emission is near 10^3 Lsun, by comparison of the sources in our sample with previously detected methanol maser sources. We examine the IRAS properties of our sample and compare them with sources previously observed for methanol maser emission, almost all of which satisfy the Wood & Churchwell criterion for selecting candidate UCHII regions. We find that about half of our sample satisfy this criterion, and in addition almost all of this subgroup have integrated fluxes between 25 and 60 microns that are similar to sources with detectable methanol maser emission. By identifying a number of low-mass protostars in this work and from the literature that satisfy the Wood & Churchwell criterion for candidate UCHII regions, we show conclusively for the first time that the fainter flux end of their sample is contaminated by lower-mass non-ionizing sources, confirming the suggestion by van der Walt and Ramesh & Sridharan.Comment: 8 pages with 2 figures. Accepted by Ap

Ice absorption features in the 5-8 μm region toward embedded protostars

We have obtained 5-8 μm spectra towards 10 embedded protostars using the Short Wavelength Spectrometer on board the Infrared Space Observatory (ISO-SWS) with the aim of studying the composition of interstellar ices. The spectra are dominated by absorption bands at 6.0 μm and 6.85 μm. The observed peak positions, widths and relative intensities of these bands vary dramatically along the different lines of sight. On the basis of comparison with laboratory spectra, the bulk of the 6.0 μm absorption band is assigned to amorphous H_2O ice. Additional absorption, in this band, is seen toward 5 sources on the short wavelength wing, near 5.8 μm, and the long wavelength side near 6.2 μm. We attribute the short wavelength absorption to a combination of formic acid (HCOOH) and formaldehyde (H_2CO), while the long wavelength absorption has been assigned to the C-C stretching mode of aromatic structures. From an analysis of the 6.85 μm band, we conclude that this band is composed of two components: a volatile component centered near 6.75 μm and a more refractory component at 6.95 μm. From a comparison with various temperature tracers of the thermal history of interstellar ices, we conclude that the two 6.85 μm components are related through thermal processing. We explore several possible carriers of the 6.85 absorption band, but no satisfactory identification can be made at present. Finally, we discuss the possible implications for the origin and evolution of interstellar ices that arise from these new results

Speckle tracking echocardiography: new ways of translational approaches in preeclampsia to detect cardiovascular dysfunction

Several studies have shown that women with a preeclamptic pregnancy exhibit an increased risk of cardiovascular disease. However, the underlying molecular mechanisms are unknown. Animal models are essential to investigate the causes of this increased risk and have the ability to assess possible preventive and therapeutic interventions. Using the latest technologies such as speckle tracking echocardiography (STE), it is feasible to map subclinical changes in cardiac diastolic and systolic function as well as structural changes of the maternal heart. The aim of this work is to compare cardiovascular changes in an established transgenic rat model with preeclampsia-like pregnancies with findings from human preeclamptic pregnancies by STE. The same algorithms were used to evaluate and compare the changes in echos of human and rodents. Parameters of functionality like global longitudinal strain (animal -23.54 ± 1.82 % vs. -13.79 ± 0.57 %, human -20.60 ± 0.47 % vs. -15.45 ± 1.55 %) as well as indications of morphological changes like relative wall thickness (animal 0.20 ± 0.01 vs. 0.25 ± 0.01, human 0.34 ± 0.01 vs. 0.40 ± 0.02) are significantly altered in both species after preeclamptic pregnancies. Thus, the described rat model simulates the human situation quite well and is a valuable tool for future investigations regarding cardiovascular changes. STE is a unique technique which can be applied in animal models and human with a high potential to uncover cardiovascular maladaptation and subtle pathologies

The Role of Polycyclic Aromatic Hydrocarbons in Ultraviolet Extinction. I. Probing small molecular PAHs

We have obtained new STIS/HST spectra to search for structure in the ultraviolet interstellar extinction curve, with particular emphasis on a search for absorption features produced by polycyclic aromatic hydrocarbons (PAHs). The presence of these molecules in the interstellar medium has been postulated to explain the infrared emission features seen in the 3-13 $\mu$m spectra of numerous sources. UV spectra are uniquely capable of identifying specific PAH molecules. We obtained high S/N UV spectra of stars which are significantly more reddened than those observed in previous studies. These data put limits on the role of small (30-50 carbon atoms) PAHs in UV extinction and call for further observations to probe the role of larger PAHs. PAHs are of importance because of their ubiquity and high abundance inferred from the infrared data and also because they may link the molecular and dust phases of the interstellar medium. A presence or absence of ultraviolet absorption bands due to PAHs could be a definitive test of this hypothesis. We should be able to detect a 20 \AA wide feature down to a 3$\sigma$ limit of $\sim$0.02 A$_V$. No such absorption features are seen other than the well-known 2175 \AA bump.Comment: 16 pages, 3 figure, ApJ in pres