SS433's jet trace from ALMA imaging and Global Jet Watch spectroscopy: evidence for post-launch particle acceleration

We present a comparison of Doppler-shifted H-alpha line emission observed by the Global Jet Watch from freshly-launched jet ejecta at the nucleus of the Galactic microquasar SS433 with subsequent ALMA imaging at mm-wavelengths of the same jet ejecta. There is a remarkable similarity between the transversely-resolved synchrotron emission and the prediction of the jet trace from optical spectroscopy: this is an a priori prediction not an a posteriori fit, confirming the ballistic nature of the jet propagation. The mm-wavelength of the ALMA polarimetry is sufficiently short that the Faraday rotation is negligible and therefore that the observed E-vector directions are accurately orthogonal to the projected local magnetic field. Close to the nucleus the B-field vectors are perpendicular to the direction of propagation. Further out from the nucleus, the B-field vectors that are coincident with the jet instead become parallel to the ridge line; this occurs at a distance where the jet bolides are expected to expand into one another. X-ray variability has also been observed at this location; this has a natural explanation if shocks from the expanding and colliding bolides cause particle acceleration. In regions distinctly separate from the jet ridge line, the fractional polarisation approaches the theoretical maximum for synchrotron emission.Comment: To appear in ApJ Letter

Distances of Stars by mean of the Phase-lag Method

Variable OH/IR stars are Asymptotic Giant Branch (AGB) stars with an optically thick circumstellar envelope that emit strong OH 1612 MHz emission. They are commonly observed throughout the Galaxy but also in the LMC and SMC. Hence, the precise inference of the distances of these stars will ultimately result in better constraints on their mass range in different metallicity environments. Through a multi-year long-term monitoring program at the Nancay Radio telescope (NRT) and a complementary high-sensitivity mapping campaign at the eMERLIN and JVLA to measure precisely the angular diameter of the envelopes, we have been re-exploring distance determination through the phase-lag method for a sample of stars, in order to refine the poorly-constrained distances of some and infer the currently unknown distances of others. We present here an update of this project.Comment: 4 pages, 1 figure, 2 tables, to appear in the Proceedings of the IAU Symposium No. 336: Astrophysical Masers: Unlocking the Mysteries of the Univers

Multi-wavelength Radio Continuum Emission Studies of Dust-free Red Giants

Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths however, and previous observations have provided only a small number of modest S/N measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (Alpha Boo: K2 III) and Aldebaran (Alpha Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for Alpha Boo. This is the first time single luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of Alpha Boo's atmosphere where its wind velocity is approaching its terminal value and the ionization balance is becoming frozen-in. For Alpha Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of Alpha Boo. Finally, we develop a simple analytical wind model for Alpha Boo based on our new long-wavelength flux measurements

The pathophysiology of paroxysmal nocturnal hemoglobinuria and treatment with eculizumab

Paroxysmal nocturnal hemoglobinuria is a rare disorder of hemopoietic stem cells. Affected individuals have a triad of clinical associations – intravascular hemolysis, an increased risk of thromboembolism, and bone marrow failure. Most of the symptoms experienced in this disease occur due to the absence of complement regulatory proteins on the surface of the red blood cells. Complement activation is thus not checked and causes destruction of these cells. Eculizumab is a monoclonal antibody treatment which specifically binds to the complement protein C5, preventing its cleavage, and so halts the complement cascade and prevents the formation of the terminal complement proteins. Eculizumab prevents intravascular hemolysis, stabilizes hemoglobin levels, reduces or stops the need for blood transfusions, and improves fatigue and patient quality of life as well as reducing pulmonary hypertension, decreasing the risk of thrombosis and protecting against worsening renal function. It is not a curative therapy but has a great benefit on those with this rare debilitating condition

Temporal Evolution of the Size and Temperature of Betelgeuse's Extended Atmosphere

We use the Very Large Array (VLA) in the A configuration with the Pie Town (PT) Very Long Baseline Array (VLBA) antenna to spatially resolve the extended atmosphere of Betelgeuse over multiple epochs at 0.7, 1.3, 2.0, 3.5, and 6.1 cm. The extended atmosphere deviates from circular symmetry at all wavelengths while at some epochs we find possible evidence for small pockets of gas significantly cooler than the mean global temperature. We find no evidence for the recently reported e-MERLIN radio hotspots in any of our multi-epoch VLA/PT data, despite having sufficient spatial resolution and sensitivity at short wavelengths, and conclude that these radio hotspots are most likely interferometric artefacts. The mean gas temperature of the extended atmosphere has a typical value of 3000 K at 2 $R_{\star}$ and decreases to 1800 K at 6 $R_{\star}$, in broad agreement with the findings of the single epoch study from Lim et al. (1998). The overall temperature profile of the extended atmosphere between $2 R_{\star} \lesssim r \lesssim 6 R_{\star}$ can be described by a power law of the form $T_{\mathrm{gas}}(r) \propto r^{-0.6}$, with temporal variability of a few 100 K evident at some epochs. Finally, we present over 12 years of V band photometry, part of which overlaps our multi-epoch radio data. We find a correlation between the fractional flux density variability at V band with most radio wavelengths. This correlation is likely due to shock waves induced by stellar pulsations, which heat the inner atmosphere and ionize the more extended atmosphere through radiative means. Stellar pulsations may play an important role in exciting Betelgeuse's extended atmosphere

IVOA Recommendation: Data Model for Astronomical DataSet Characterisation

This document defines the high level metadata necessary to describe the physical parameter space of observed or simulated astronomical data sets, such as 2D-images, data cubes, X-ray event lists, IFU data, etc.. The Characterisation data model is an abstraction which can be used to derive a structured description of any relevant data and thus to facilitate its discovery and scientific interpretation. The model aims at facilitating the manipulation of heterogeneous data in any VO framework or portal. A VO Characterisation instance can include descriptions of the data axes, the range of coordinates covered by the data, and details of the data sampling and resolution on each axis. These descriptions should be in terms of physical variables, independent of instrumental signatures as far as possible. Implementations of this model has been described in the IVOA Note available at: http://www.ivoa.net/Documents/latest/ImplementationCharacterisation.html Utypes derived from this version of the UML model are listed and commented in the following IVOA Note: http://www.ivoa.net/Documents/latest/UtypeListCharacterisationDM.html An XML schema has been build up from the UML model and is available at: http://www.ivoa.net/xml/Characterisation/Characterisation-v1.11.xsdComment: http://www.ivoa.ne

Spectroscopic probe for in vivo measurement of raman signals

An optical probe is disclosed which is suitable for rapidly measuring Raman spectra in vivo. The probe is designed to minimize interfering Raman and fluorescence signals generated within the probe itself. In addition, the probe design is compact, making it particularly suited for use in confined spaces such as body cavities. In one embodiment, the probe is employed to detect tissue abnormalities such as cervical cancers and precancers.Board of Regents, University of Texas Syste

Astronomical Data Management

We present a summary of the major contributions to the Special Session on Data Management held at the IAU General Assembly in Prague in 2006. While recent years have seen enormous improvements in access to astronomical data, and the Virtual Observatory aims to provide astronomers with seamless access to on-line resources, more attention needs to be paid to ensuring the quality and completeness of those resources. For example, data produced by telescopes are not always made available to the astronomical community, and new instruments are sometimes designed and built with insufficient planning for data management, while older but valuable legacy data often remain undigitised. Data and results published in journals do not always appear in the data centres, and astronomers in developing countries sometimes have inadequate access to on-line resources. To address these issues, an 'Astronomers Data Manifesto' has been formulated with the aim of initiating a discussion that will lead to the development of a 'code of best practice' in astronomical data management.Comment: Proceedings of Special Session SPS6 (Astronomical Data Management) at the IAU GA 2006. To appear in Highlights of Astronomy, Volume 14, ed. K.A. van der Huch

Investigating the impact of experiential learning on employability skill development and employment outcomes: a UK case study of MBA students from the Indian Subcontinent

Global economic events have had a profound effect upon both businesses and the available workforce. Industries need a more skilful and advanced labour market and individuals who complete tertiary-level education are afforded better protection against economic uncertainties. Consequently, demand for higher education worldwide is growing, due to a rising number of globally mobile students. However, return on investment is important and curriculums offering employability enhancement and work opportunities are motivating factors when international students make their study decisions. This paper details one UK university’s approach to enhancing international student employability skills and employment outcomes, using a 3-day experiential learning residential on an MBA programme. Employing a survey design, the research investigates the benefits of this residential to 182 international MBA students (all from the Indian subcontinent region). The findings report that the international students developed key employability skills via the residential which significantly increased their propensity to obtain subsequent employment. The results of this paper provide much needed insight into improving both the employability skills and employment outcomes of international students, especially students from the Indian subcontinent, via immersive experiential learning activities