High Resolution Spectroscopy of SN1987A's Rings: He I 10830 and H-alpha from the Hotspots

We present the first high-dispersion spectroscopy of He I 10830 from the hotspots in the ring around SN1987A, obtained at Gemini South, spatially resolving the near and far sides of the ring. We compare these line profiles to similar echelle spectra of H$\alpha$ and [N II] 6583 obtained at the Magellan Observatory. We find that the He I profiles are much broader than H-alpha or [N II], but the He I profiles also have different shapes -- they have enhanced emission at high speeds, with extra blueshifted emission on the north side of the ring, and extra redshifted emission on the south side. To explain this, we invoke a simple geometric picture where the extra He I emission traces hotter gas from faster shocks that strike the apex of the hotspots directly, while the H-alpha preferentially traces cooler lower-ionization gas from slower transverse shocks that penetrate into the sides of the ring.Comment: 3 pages. To appear in proceedings: "Supernova 1987A: 20 Years After: Supernovae and Gamma-Ray Bursters" AIP, New York, eds. S. Immler, K.W. Weiler, and R. McCra

Dust-Gas Interaction in SNR 1987A

Multiwavelength observations of SNR 1987A show that its morphology is rapidly changing at X-ray, radio, and optical wavelengths as the blast wave from the explosion expands into the circumstellar equatorial ring. Infrared emission arises from the interaction of dust grains with the hot X-ray emitting gas. We show that the IR emission provides important complementary information on the interaction of the SN blast wave with the circumstellar equatorial ring that cannot be obtained at any other wavelength.Comment: 8 pages, 4 figures; review talk to appear in the AIP Proceedings of the Conference " Supernova 1987A: 20 Years after - Supernovae and Gamma-Ray Bursters" held in Aspen Co USA, Feb 19-23, 200

Improving para sports concussion care:The blind leading the blind

Very little is known about para sports injuries in general, despite organised para sports competitions having been held 112 years ago. Only recently have consensus guidelines been published on the recording and reporting of data for injury and illness surveillance studies in para sport. Faced with this emerging field, even less is known about the incidence and prevalence of concussions, perhaps because of a research vacuum in the assessment, diagnosis, and management of concussions in para sport. The primary objective of this thesis is to begin the process of building an evidence-informed foundation for para concussion care. Achieving this objective will require understanding the context of para concussions, of adapting existing clinical guidelines on sports concussions for para athletes and of developing guidelines specific to this athlete population. This thesis will use mixed methods. Chapter 2 describes a systematic review of existing prospective injury surveillance studies in para sports to understand the quality of what is thought to be known on the wider subject of injuries within para sports. Chapter 3 contains a prospective injury surveillance study in a para football cohort, which will give insight into whether the risk of head injuries can be determined longitudinally rather than in short-term studies looking at shorter competitions. Chapter 4 compares preseason baseline SCAT3 scores for a range of England international footballers (with and without impairments). In the absence of normative data for SCAT3 scores and insights into the usability of SCAT3 for athletes with a disability, this study will aim to determine whether differences exist between baseline SCAT3 scores for footballers with and without disability. Chapter 5 is a Position Statement providing specific recommendations and guidance related to para athletes and their attending medical professionals in case a para athlete sustains a suspected concussion. A multidisciplinary group of experts and para athletes was convened with clinical or academic expertise within the para sport and para concussion (Concussion in Para Sport - CIPS) Group. Chapter 5 includes an Infographic representation of the Position Statement. Chapter 6 contains an exploratory qualitative study employing semi-structured interviews with current or retired (still playing club football) male English blind footballers. This chapter assesses the athletes’ perceptions of concussion, concussion risks, and concussion prevention based on their experiences in para football. This chapter should lead to new insights into concussion care for para athletes (and possibly non-para athletes). Chapter 6 includes an Infographic representation of the study. Chapter 7 is a general discussion in which the results of the various studies conducted are discussed in a broader context

On Big Bang Relics, the Neutrino Mass and the Spectrum of Cosmic Rays

It is shown that high-energy features of the cosmic ray spectrum, in particular the kink around 4 PeV and the corresponding change in spectral index, may be explained from interactions between highly energetic cosmic protons and relic Big Bang antineutrinos, if the latter have a rest mass of about 0.4 eV/$c^2$. This explanation is supported by experimental data from extensive air-shower experiments, and in particular by the observation (Fly's Eye) of a second kink around 300 PeV, and by the abrupt change in the chemical composition of the cosmic ray spectrum that occurs at that energy. Both facts follow naturally from our theory, which predicts additional verifiable features of the cosmic ray spectrum in the few-PeV region, e.g. an abrupt decrease in the $p/\alpha$ ratio.Comment: 6 pages, 3 figures, Proceedings of the 6th Topical Seminar on Neutrino and Astroparticle Physics, San Miniato (Italy), 17-21 May 199

Radio Detection of SN 1986E in NGC 4302

Radio observations of SN 1986E have shown a clear detection of emission at 6 cm wavelength about 8 months after optical discovery. Combined with a number of new upper limits and a study of the possible models, it appears that SN 1986E was probably a fairly normal Type IIL supernova, somewhat similar to SN 1980K, with radio emission at roughly expected levels. This detection continues the correlation between radio detection and late time optical emission.Comment: 14 pages, LaTeX (AASTeX), 2 PostScript figures, to appear in ApJ (Letters

Radio emission from SNe and young SNRs

Study of radio supernovae (RSNe), the earliest stages of supernova remnant (SNR) formation, over the past 20 years includes two dozen detected objects and more than 100 upper limits. From this work we are able to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the stellar system, and to show clumpiness of the circumstellar material. More speculatively, it may be possible to provide distance estimates to RSNe

Feature Selection and Dimensionality Reduction in Genomics and Proteomics

International audienceFinding reliable, meaningful patterns in data with high numbers of attributes can be extremely difficult. Feature selection helps us to decide what attributes or combination of attributes are most important for finding these patterns. In this chapter, we study feature selection methods for building classification models from high-throughput genomic (microarray) and proteomic (mass spectrometry) data sets. Thousands of feature candidates must be analyzed, compared and combined in such data sets. We describe the basics of four different approaches used for feature selection and illustrate their effects on an MS cancer proteomic data set. The closing discussion provides assistance in performing an analysis in high-dimensional genomic and proteomic data

Radio Emission from SN 1994I in NGC 5194 (M 51) - The Best Studied Type Ib/c Radio Supernova

We present the results of detailed monitoring of the radio emission from the Type Ic supernova SN 1994I from 3 days after optical discovery on 1994 March 31 until eight years later at age 2927 days on 2002 April 05. The data were mainly obtained using the Very Large Array at the five wavelengths, 1.3, 2.0, 3.6, 6.2, and 21 cm, and from the Cambridge 5 km Ryle Telescope at 2.0 cm. Two additional measurements were obtained at millimeter wavelengths. This data set represents the most complete, multifrequency radio observations ever obtained for a Type Ib/c supernova. The radio emission evolves regularly in both time and frequency and is well described by established SN emission/absorption models. It is the first radio supernova with sufficient data to show that it is clearly dominated by the effects of synchrotron self-absorption at early times.Comment: 43 pages, 5 figure