Spin splitting of X-related donor impurity states in an AlAs barrier

We use magnetotunneling spectroscopy to observe the spin splitting of the ground state of an X-valley-related Si-donor impurity in an AlAs barrier. We determine the absolute magnitude of the effective Zeeman spin splitting factors of the impurity ground state to be g$_{I}$= 2.2 $\pm$ 0.1. We also investigate the spatial form of the electron wave function of the donor ground state, which is anisotropic in the growth plane

Bis(dimethyl sulfoxide)hydridobis(triphenylphosphane)cobalt(I)

The title compound, [CoH(C18H15P)2(C 2H6OS)2], was synthesized by the reaction of chloridotris(triphenyl-phosphane)cobalt(I), [ClCo(PPh3)3], in the presence of one equivalent potassium hydridotris(pyrazol-yl)borate in dimethyl sulfoxide. The structure displays a distorted trigonal-pyramidally coordinated cobalt(I) atom, with two phosphane ligands and one DMSO ligand in the equatorial plane. The coordination is completed by one further DMSO ligand and the anionic hydride in the axial positions

A Giant Crater on 90 Antiope?

Mutual event observations between the two components of 90 Antiope were carried out in 2007-2008. The pole position was refined to lambda0 = 199.5+/-0.5 eg and beta0 = 39.8+/-5 deg in J2000 ecliptic coordinates, leaving intact the physical solution for the components, assimilated to two perfect Roche ellipsoids, and derived after the 2005 mutual event season (Descamps et al., 2007). Furthermore, a large-scale geological depression, located on one of the components, was introduced to better match the observed lightcurves. This vast geological feature of about 68 km in diameter, which could be postulated as a bowl-shaped impact crater, is indeed responsible of the photometric asymmetries seen on the "shoulders" of the lightcurves. The bulk density was then recomputed to 1.28+/-0.04 gcm-3 to take into account this large-scale non-convexity. This giant crater could be the aftermath of a tremendous collision of a 100-km sized proto-Antiope with another Themis family member. This statement is supported by the fact that Antiope is sufficiently porous (~50%) to survive such an impact without being wholly destroyed. This violent shock would have then imparted enough angular momentum for fissioning of proto-Antiope into two equisized bodies. We calculated that the impactor must have a diameter greater than ~17 km, for an impact velocity ranging between 1 and 4 km/s. With such a projectile, this event has a substantial 50% probability to have occurred over the age of the Themis family.Comment: 30 pages, 3 Tables, 8 Figures. Accepted for publication in Icaru

India: street vendors, fish markets and food security

While women in fisheries cope with the challenges of changing market systems, persistent gender inequities threaten to impact livelihoods and food security

How Seafood Wholesale Markets Matter for Urban Food Security:Evidence from Chennai, India

Urban sites gather poverty in particular locations and often require bulk food system approaches for addressing prevalent food security and nutrition needs. The food systems that service them are, however, characterized by perishability and large irregularities in supply. Seafood is currently recognized as contributing in a major way to food security and nutrition, and it is to assessing the role of wholesale markets in meeting the needs of the urban poor that this paper is directed. It zooms in on the city of Chennai, India, where an estimated 40% of the population is considered poor and marine fish plays a crucial role in diets. Building on one-and-a-half years of field research in the pre-COVID-19 period, the paper analyses the performance of one of the city’s largest fish wholesale markets, Vanagaram, in relation to the four commonly recognized pillars of food security. Results demonstrate how urban food systems function as major suppliers of fish (and other food items) to thousands of low- and middle-income households. Most importantly, this case study demonstrates the crucial role that is played by wholesale markets in merging low-price fish supplies from different geographic regions and thereby ensuring food security of poorer inhabitants

Trans-Di-μ-acetato-[μ-N,N-bis-(diphenyl-phosphino)aniline] bis-[chlorido-molybdenum(II)](Mo - Mo)-dichloro-methane-tetra-hydro-furan (1/0.3/1.7)

The mol-ecular structure of the title compound, [Mo2(CH 3COO)2Cl2(C30H25NP 2)]·0.3CH2Cl2·1.7C 4H8O, features an Mo - Mo dumbbell bridged by two acetate groups which are trans to each other. Perpendicular to the plane spanned by the acetate groups, the Ph2PN(Ph)PPh2 ligand bridges both Mo atoms, having a P - N - P angle of 114.09 (19)°. In a trans position to the PNP ligand are two Cl atoms, one on each molybdenum centre. The Mo - Mo bond distance is 2.1161 (9) Å, within the range known for Mo - Mo quadruple bonds. The Mo complex is located on a crystallographic twofold rotation axis which runs through the N - C bond of the ligand. The site occupation factors of the disordered solvent molecules were fixed to 0.15 for dichloromethane and 0.85 for tetrahydrofuran. © 2009

[N,N-Bis(diphenyl­phosphino)isopropyl­amine]dibromidonickel(II)

The title compound, [NiBr2(C27H27NP2)], was synthesized by the reaction of NiBr2(dme) (dme is 1,2-dimethoxy-ethane) with N,N-bis-(diphenyl-phosphino)isopropyl-amine in methanol/tetra-hydro-furan. The nickel(II) center is coordinated by two P atoms of the chelating PNP ligand, PH2PN(iPr)PPH2, and two bromide ions in a distorted square-planar geometry

Workshop on the Space Environment: The Effects on the Optical Properties of Airless Bodies

Reflectance spectrophotometry and polarimetry are major tools in remote sensing studies of surfaces of solar system bodies. The interpretations of such measurements are often based on laboratory studies of meteoritic, lunar, and terrestrial materials. However, the optical properties of regoliths are known to be affected by the space environment. Thus, some of the major questions addressed in the workshop include identity of the soil component responsible for alteration of the optical properties, the process that produced this component, and how reliably the effects of these processes could be extrapolated to other bodies of the solar system

Magnetic-field-induced singularities in spin dependent tunneling through InAs quantum dots

Current steps attributed to resonant tunneling through individual InAs quantum dots embedded in a GaAs-AlAs-GaAs tunneling device are investigated experimentally in magnetic fields up to 28 T. The steps evolve into strongly enhanced current peaks in high fields. This can be understood as a field-induced Fermi-edge singularity due to the Coulomb interaction between the tunneling electron on the quantum dot and the partly spin polarized Fermi sea in the Landau quantized three-dimensional emitter.Comment: 5 pages, 4 figure

Water Ice on the Satellite of Kuiper Belt Object 2003 EL61

We have obtained a near infrared spectrum of the brightest satellite of the large Kuiper Belt Object, 2003 EL61. The spectrum has absorption features at 1.5 and 2.0 microns, indicating that water ice is present on the surface. We find that the satellite's absorption lines are much deeper than water ice features typically found on Kuiper Belt Objects. We argue that the unusual spectrum indicates that the satellite was likely formed by impact and not by capture