Sub-au imaging of water vapour clouds around four Asymptotic Giant Branch stars

We present MERLIN maps of the 22-GHz H2O masers around four low-mass late-type stars (IK Tau U Ori, RT Vir and U Her), made with an angular resolution of ~ 15 milliarcsec and a velocity resolution of 0.1 km s-1. The H2O masers are found in thick expanding shells with inner radii ~ 6 to 16 au and outer radii four times larger. The expansion velocity increases radially through the H2O maser regions, with logarithmic velocity gradients of 0.5--0.9. IK Tau and RT Vir have well-filled H2O maser shells with a spatial offset between the near and far sides of the shell, which suggests that the masers are distributed in oblate spheroids inclined to the line of sight. U Ori and U Her have elongated poorly-filled shells with indications that the masers at the inner edge have been compressed by shocks; these stars also show OH maser flares. MERLIN resolves individual maser clouds, which have diameters of 2 -- 4 au and filling factors of only ~ 0.01 with respect to the whole H2O maser shells. The CSE velocity structure gives additional evidence the maser clouds are density bounded. Masing clouds can be identified over a similar timescale to their sound crossing time (~2 yr) but not longer. The sizes and observed lifetimes of these clouds are an order of magnitude smaller than those around red supergiants, similar to the ratio of low-mass:high-mass stellar masses and sizes. This suggests that cloud size is determined by stellar properties, not local physical phenomena in the wind.Comment: 21 pages, including 14 figures and 8 tables. Accepted for publication in MNRA

Moans, Palpable Groin, and Entrapment of Bone: A Case of Malignant Peripheral Nerve Sheath Tumor in an otherwise Healthy Hispanic Male

Background: Malignant peripheral nerve sheath tumors (MPNTs) are rare malignant soft tissue sarcomas that have an incidence of about 0.001 %. MPNTs typically occur in individuals who have neurofibromatosis or secondary to radiation therapy and rarely occur sporadically. We present a case of a previously healthy 56-year-old gentleman who was diagnosed with MPNTs. Case: A healthy 56-year-old gentleman presented with worsening LLQ abdominal pain for 6 months. Associated symptoms included bloating, LLE swelling, early satiety for the past 2 months, and a 5-10lb unintentional weight loss. Patient denied recent cough, night sweats, dyspnea, fever, chills, melena or hematochezia. Vitals were WNL. Physical examination revealed a palpable mass on LLQ extending into the groin and edema of the left leg with diminished strength 3/5. CBC and CMP were unremarkable. CT abdomen showed a large necrotic mass in the left retroperitoneum infiltrating along the iliopsoas musculature, extending into the left hip and into the left side of L3, L4, L5 vertebral bodies and through L4 transverse process measuring up to 24.6 x 11.5 x 13 cm. Pathology revealed spindle cell sarcoma composed of moderately atypical, elongated spindle cells positive for vimentin, with loss of H3/K27me3, and negative for SMA, S-100 consistent with MPNSTs. Conclusions: The is a rare case of a sporadic presentation of MPNTs. Treatment depends on the extent of tumor burden and metastatic disease is typically treated with chemotherapy. CT chest showed innumerable pulmonary nodules. Patient is currently being treated with Doxorubicin and Ifosfamide with minimal response

Galactic Extinction from Colors and Counts of Field Galaxies in WFPC2 Frames: An Application to GRB 970228

We develop the ``simulated extinction method'' to measure average foreground Galactic extinction from field galaxy number-counts and colors. The method comprises simulating extinction in suitable reference fields by changing the isophotal detection limit. This procedure takes into account selection effects, in particular, the change in isophotal detection limit (and hence in isophotal magnitude completeness limit) with extinction, and the galaxy color--magnitude relation. We present a first application of the method to the HST WFPC2 images of the gamma-ray burster GRB 970228. Four different WFPC2 high-latitude fields, including the HDF, are used as reference to measure the average extinction towards the GRB in the F606W passband. From the counts, we derive an average extinction of A_V = 0.5 mag, but the dispersion of 0.4 mag between the estimates from the different reference fields is significantly larger than can be accounted by Poisson plus clustering uncertainties. Although the counts differ, the average colors of the field galaxies agree well. The extinction implied by the average color difference between the GRB field and the reference galaxies is A_V = 0.6 mag, with a dispersion in the estimated extinction from the four reference fields of only 0.1 mag. All our estimates are in good agreement with the value of 0.81\pm0.27 mag obtained by Burstein & Heiles, and with the extinction of 0.78\pm0.12 measured by Schlegel et al. from maps of dust IR emission. However, the discrepancy between the widely varying counts and the very stable colors in these high-latitude fields is worth investigating.Comment: 14 pages, 2 figures; submitted to the Astrophysical Journa

Superscaling in the resonance region for neutrino-nucleus scattering: The SuSAv2-DCC model

In this work the SuSAv2 and dynamical coupled-channels (DCC) models have been combined and tested in the inelastic regime for electron and neutrino reactions on nuclei. The DCC model, an approach to study baryon resonances through electron and neutrino induced meson production reactions, has been implemented for the first time in the SuSAv2-inelastic model to analyze the resonance region. Within this framework, we also present a novel description about other inelasticities in the resonance region (SoftDIS). The outcomes of these approaches are firstly benchmarked against (e,e') data on 12C. The description is thus extended to the study of neutrino-nucleus inclusive cross sections on 12C and 40Ar and compared with data from the T2K, MicroBooNE, ArgoNEUT and MINERvA experiments, thus covering a wide kinematical range.Comment: Submitted to Physical Review