Theoretical research program to predict the properties of molecules and clusters containing transition metal atoms

The primary focus of this research has been the theoretical study of transition metal (TM) chemistry. A major goal of this work is to provide reliable information about the interaction of H atoms with iron metal. This information is needed to understand the effect of H atoms on the processes of embrittlement and crack propagation in iron. The method in the iron hydrogen studies is the cluster method in which the bulk metal is modelled by a finite number of iron atoms. There are several difficulties in the application of this approach to the hydrogen iron system. First the nature of TM-TM and TM-H bonding for even diatomic molecules was not well understood when these studies were started. Secondly relatively large iron clusters are needed to provide reasonable results

The impact of turbulence and magnetic field orientation on star forming filaments

We present simulations of collapsing filaments studying the impact of turbulence and magnetic field morphologies on their evolution and star formation properties. We vary the mass per unit length of the filaments as well as the orientation of the magnetic field with respect to the major axis. We find that the filaments, which have no or a perpendicular magnetic field, typically reveal a smaller width than the universal width of 0.1 pc proposed by e.g. Arzoumanian et al. 2011. We show that this also holds in the presence of supersonic turbulence and that accretion driven turbulence is too weak to stabilize the filaments along their radial direction. On the other hand, we find that a magnetic field that is parallel to the major axis can stabilize the filament against radial collapse resulting in widths of 0.1 pc. Furthermore, depending on the filament mass and magnetic field configuration, gravitational collapse and fragmentation in filaments occurs either in an edge-on way, uniformly distributed across the entire length, or in a mixed way. In the presence of initially moderate density perturbations, a centralized collapse towards a common gravitational centre occurs. Our simulations can thus reproduce different modes of fragmentation observed recently in star forming filaments. Moreover, we find that turbulent motions influence the distance between individual fragments along the filament, which does not always match the results of a Jeans analysis.Comment: 14 pages, 8 figure, accepted for publication in MNRA

Book Review

Book review of "Dealing in Virtue: International Commercial Arbitration and the Construction of a Transnational Legal Order" by Yves Dezalay and Bryant G. Garth (Chicago: University of Chicago Press, 1996).Published in cooperation with the American Bar Association Section of Dispute Resolutio

Revealing the dynamics of Class 0 protostellar discs with ALMA

We present synthetic ALMA observations of Keplerian, protostellar discs in the Class 0 stage studying the emission of molecular tracers like $^{13}$CO, C$^{18}$O, HCO$^+$, H$^{13}$CO$^+$, N$_2$H$^+$, and H$_2$CO. We model the emission of discs around low- and intermediate-mass protostars. We show that under optimal observing conditions ALMA is able to detect the discs already in the earliest stage of protostellar evolution, although the emission is often concentrated to the innermost 50 AU. Therefore, a resolution of a few 0.1" might be too low to detect Keplerian discs around Class 0 objects. We also demonstrate that under optimal conditions for edge-on discs Keplerian rotation signatures are recognisable, from which protostellar masses can be inferred. For this we here introduce a new approach, which allows us to determine protostellar masses with higher fidelity than before. Furthermore, we show that it is possible to reveal Keplerian rotation even for strongly inclined discs and that ALMA should be able to detect possible signs of fragmentation in face-on discs. In order to give some guidance for future ALMA observations, we investigate the influence of varying observing conditions and source distances. We show that it is possible to probe Keplerian rotation in inclined discs with an observing time of 2 h and a resolution of 0.1", even in the case of moderate weather conditions. Furthermore, we demonstrate that under optimal conditions, Keplerian discs around intermediate-mass protostars should be detectable up to kpc-distances.Comment: 17 pages, 17 figures, accepted for publication by MNRA

Utah High School Sophomore Attitudes Toward Women\u27s Roles and Non-Traditional Vocational Career Choices

Role behaviors for men and women in our society are undergoing change. Research data to reveal student attitudes toward these role behaviors and choices were needed for the development of strategies to eliminate sex bias and sex stereotyping in our educational programs and ultimately in the socialization process. The purpose of the study was to collect research data to determine Utah high school student attitudes toward women\u27s roles and non-traditional vocational career choices. The survey instrument used to collect the data was constructed, pilot tested, factor analyzed, and revised prior to its administration to the sample. The revised instrument contained 60 attitudinal statements regarding women\u27s roles and non-traditional vocational career chokes and demographic data requests. Instrument reliability was determined on each of the factors using the Guttman Split-half. The Factor I coefficient of reliability was .91. The reliability coefficient on Factor II was .82, while the Factor III reliability coefficient was .81. A total of 23 Utah public high schools and 1,454 sophomore students participated in the study. The data were analyzed using Five-way Analysis of Variance and Chi Square programs (Statistical Package for the Social Sciences). The Total Attitudinal Score, based on Women\u27s Roles and Non-Traditional Vocational Career Choices, and three factor scores were the dependent variables analyzed. The factor scores included: Factor I, Women\u27s Place--Women\u27s Roles; Factor II, Sex Role Equity--Equal Treatment; and Factor III, Leadership Roles. Comparisons were made on total score and three factor scores based on the five independent variables: Sex (male/female), Religious Commitment (high/low), Location of Family Residence (rural/metro), Mother\u27s Employment Status (employed/not employed), and Social Class (middle/working). A significant difference was found between male and female student attitudes for each factor and the total score. On each comparison of the Sex variable, female attitudes toward women\u27s roles and choices were more non-traditional than male attitudes. For comparisons on the Religious Commitment variable, a significant difference was found in attitudes between students of high and low religious commitment on total score and each of the factor scores. Students of low religious commitment held more non-traditional attitudes toward women\u27s roles and choices than students of high religious commitment. A significant difference was found on the Location of Family Residence variable for Total Attitudinal Score. Students from metropolitan locations responded more non-traditionally toward women\u27s roles and non-traditional vocational career choices than students from rural locations. Differences in rural and metropolitan student attitudes were not found to be significant for Factor I, Factor II, and Factor III scores. Significant differences in student attitudes were found on the Mother\u27s Employment Status variable on total score and each of the factor scores. Students whose mothers were employed outside the home held more non-traditional attitudes toward women\u27s roles and related career choices than students with homemaker mothers. Findings on the Social Class variable were found to be significant for the Total Attitudinal Score and Factor scores II and III. A significant difference was found in attitudes between students from middle class families and students from working class families. Students from middle class families held more non-traditional attitudes toward roles and related career choices for women than students from working class families. No significant difference was found on the Social Class variable for Factor I

Theoretical research program to study transition metal trimers and embedded clusters

Small transition metal clusters were studied at a high level of approximation, including all the valence electrons in the calculation and extensive electron correlation, in order to understand the electronic structure of these small metal clusters. By comparison of dimers, trimers, and possibly higher clusters, the information obtained was used to provide insights into the electronic structure of bulk transition metals. Small metal clusters are currently of considerable experimental interest and some information is becomming available both from matrix electron spin resonance studies and from gas phase spectroscopy. Collaboration between theorists and experimentalists is thus expected to be especially profitable at this time since there is some experimental information which can serve to guide the theoretical work

Aluminum-26 Enrichment in the Surface of Protostellar Disks Due to Protostellar Cosmic Rays

The radioactive decay of aluminum-26 ($^{26}$Al) is an important heating source in early planet formation. Since its discovery, there have been several mechanisms proposed to introduce $^{26}$Al into protoplanetary disks, primarily through contamination by external sources. We propose a local mechanism to enrich protostellar disks with $^{26}$Al through irradiation of the protostellar disk surface by cosmic rays accelerated in the protostellar accretion shock. We calculate the $^{26}$Al enrichment, [$^{26}$Al/$^{27}$Al], at the surface of the protostellar disk in the inner AU throughout the evolution of low-mass stars, from M-dwarfs to proto-Suns. Assuming constant mass accretion rates, $\dot{m}$, we find that irradiation by MeV cosmic rays can provide significant enrichment on the disk surface if the cosmic rays are not completely coupled to the gas in the accretion flow. Importantly, we find that low accretion rates, $\dot{m} < 10^{-7}$ M$_{\odot}$ yr$^{-1}$, are able to produce canonical amounts of $^{26}$Al, $[^{26}{\rm Al}/^{27}{\rm Al}] \approx 5\times10^{-5}$. These accretion rates are experienced at the transition from Class I- to Class II-type protostars, when it is assumed that calcium-aluminum-rich inclusions condense in the inner disk. We conclude that irradiation of the inner disk surface by cosmic ray protons accelerated in accretion shocks at the protostellar surface may be an important mechanism to produce $^{26}$Al. Our models show protostellar cosmic rays may be a viable model to explain the enrichment of $^{26}$Al found in the Solar System.Comment: Accepted to ApJ, in pres

Probing 3D Density and Velocity Fields of ISM in Centers of Galaxies with Future X-Ray Observations

Observations of bright and variable "reflected" X-ray emission from molecular clouds located within inner hundred parsec of our Galaxy have demonstrated that the central supermassive black hole, Sgr A*, experienced short and powerful flares in the past few hundred years. These flares offer a truly unique opportunity to determine 3D location of the illuminated clouds (with ~10 pc accuracy) and to reveal their internal structure (down to 0.1 pc scales). Short duration of the flare(s), combined with X-rays high penetration power and insensitivity of the reflection signal to thermo- and chemo-dynamical state of the gas, ensures that the provided diagnostics of the density and velocity fields is unbiased and almost free of the projection and opacity effects. Sharp and sensitive snapshots of molecular gas accessible with aid of future X-ray observatories featuring large collecting area and high angular (arcsec-level) and spectral (eV-level) resolution cryogenic bolometers will present invaluable information on properties of the supersonic turbulence inside the illuminated clouds, map their shear velocity field and allow cross-matching between X-ray data and velocity-resolved emission of various molecular species provided by ALMA and other ground-based facilities. This will highlight large and small-scale dynamics of the dense gas and help uncovering specifics of the ISM lifecycle and high-mass star formation under very extreme conditions of galactic centers. While the former is of particular importance for the SMBH feeding and triggering AGN feedback, the latter might be an excellent test case for star formation taking place in high-redshift galaxies.Comment: White paper submitted to the Astro2020 Decadal Surve