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We test the ability of Schwarzschild's orbit superposition method in measuring the mass content, scale radius and shape of a flattened dwarf spheroidal galaxy. Until now, most dynamical model efforts have assumed that dwarf spheroidal galaxies and their host halos are spherical. We use an Evans model (1993) to construct an isothermal mock galaxy whose properties somewhat resemble those of the Sculptor dwarf spheroidal galaxy. This mock galaxy contains flattened luminous and dark matter components, resulting in a logarithmic profile for the global potential. We have tested how well our Schwarzschild method could constrain the characteristic parameters of the system for different sample sizes, and also if the functional form of the potential was unknown. When assuming the true functional form of the potential, the Schwarzschild modelling technique is able to provide an accurate and precise measurement of the characteristic mass parameter of the system and reproduces well the light distribution and the stellar kinematics of our mock galaxy. When assuming a different functional form for the potential, such as a flattened NFW profile, we also constrain the mass and scale radius to their expected values. However in both cases, we find that the flattening parameter remains largely unconstrained. This is likely because the information content of the velocity dispersion on the geometric shape of the potential is too small, since $\sigma$ is constant across our mock dSph. Our results using Schwarzschild's method indicate that the mass enclosed can be derived reliably, even if the flattening parameter is unknown, and already for samples containing 2000 line-of-sight radial velocities, such as those currently available. Further applications of the method to more general distribution functions of flattened systems are needed to establish how well the flattening of dSph dark halos can be determined., Comment: 13 pages, 14 figures. Comments are welcome

High resolution N-body simulations of galactic cold dark matter haloes indicate that we should expect to find a few satellite galaxies around the Milky Way whose haloes have a maximum circular velocity in excess of 40 kms. Yet, with the exception of the Magellanic Clouds and the Sagittarius dwarf, which likely reside in subhaloes with significantly larger velocities than this, the bright satellites of the Milky Way all appear to reside in subhaloes with maximum circular velocities below 40 kms. As recently highlighted by Boylan-Kolchin et al., this discrepancy implies that the majority of the most massive subhaloes within a cold dark matter galactic halo are much too concentrated to be consistent with the kinematic data for the bright Milky Way satellites. Here we show that no such discrepancy exists if haloes are made of warm, rather than cold dark matter because these haloes are less concentrated on account of their typically later formation epochs. Warm dark matter is one of several possible explanations for the observed kinematics of the satellites., Comment: 8 pages, 7 figures, accepted by MNRAS. Text and figures updated

Dipeptidyl peptidase (DPP III) was purified from rat and human erythrocytes using an identical procedure. Electrophoretic analyses revealed the same molecular size and pI for both enzymes. The molecular mass of the human enzyme, measured by matrix-assisted laser desorption/ionization MS, was 82500ą60 Da. Its tryptic peptide mass profile was determined using the same technique, and the amino acid sequence of two internal peptides was obtained by tandem MS and Edman degradation. A search of databases revealed a high similarity between the human erythrocyte and rat liver DPP III: 21 matches out of 34 detected peptides were found, covering 40% of the total sequence. Matched peptides included the peptide harboring the characteristic HELLGH sequence motif, and a strech of 19 identical amino acids, containing Glu, a putative ligand of active site zinc. Both enzymes preferred Arg-Arg-2-naphthylamide, and were activated by micromolar Co2+, differing in their pH optima and kcat/Km. Zn2+ ions, sulfhydryl reagents, and aminopeptidase inhibitors, especially probestin, inhibited the rat DPP III more potently. The two enzymes showed the highest affinity for angiotensin III (Ki