39 research outputs found

    A new concept for the combination of optical interferometers and high-resolution spectrographs

    Full text link
    The combination of high spatial and spectral resolution in optical astronomy enables new observational approaches to many open problems in stellar and circumstellar astrophysics. However, constructing a high-resolution spectrograph for an interferometer is a costly and time-intensive undertaking. Our aim is to show that, by coupling existing high-resolution spectrographs to existing interferometers, one could observe in the domain of high spectral and spatial resolution, and avoid the construction of a new complex and expensive instrument. We investigate in this article the different challenges which arise from combining an interferometer with a high-resolution spectrograph. The requirements for the different sub-systems are determined, with special attention given to the problems of fringe tracking and dispersion. A concept study for the combination of the VLTI (Very Large Telescope Interferometer) with UVES (UV-Visual Echelle Spectrograph) is carried out, and several other specific instrument pairings are discussed. We show that the proposed combination of an interferometer with a high-resolution spectrograph is indeed feasible with current technology, for a fraction of the cost of building a whole new spectrograph. The impact on the existing instruments and their ongoing programs would be minimal.Comment: 27 pages, 9 figures, Experimental Astronomy; v2: accepted versio

    OVERHEATED SECURITY? The Securitisation of Climate Change and the Governmentalisation of Security

    Get PDF
    Since the mid-2000s, climate change has become one of the defining security issues in political as well as academic debates and amongst others has repeatedly been discussed in the UN Security Council and countless high level government reports in various countries. Beyond the question whether the characterisation as ‘security issue’ is backed up by any robust empirical findings, this begs the question whether the ‘securitisation’ of climate change itself has had tangible political consequences. Moreover, within this research area there is still a lively discussion about which security conceptions apply, how to conceptualise (successful) securitisation and whether it is a (politically and normatively) desirable approach to deal with climate change. The aim of this dissertation is to shed light on these issues and particularly to contribute to a more thorough understanding of different forms or ‘discourses’ of securitisation and their political effects on a theoretical and empirical level. Theoretically, it conceptualises securitisation as resting on different forms of power, which are derived from Michel Foucault’s governmentality lectures. The main argument is that this framework allows me to better capture the ambiguous and diverse variants of securitisation and the ever-changing concept of security as well as to come to a more thorough understanding of the political consequences and powerful effects of constructing issues in terms of security. Empirically, the thesis looks at three country cases, namely the United States, Germany and Mexico. This comparative angle allows me to go beyond the existing literature on the securitisation of climate change that mostly looks at the global level, and to come to a more comprehensive and detailed understanding of different climate security discourses and their political consequences. Concerning the main results, the thesis finds that climate change has indeed been securitised very differently in the three countries and thus has facilitated diverse political consequences. These range from an incorporation of climate change into the defence sector in the US, the legitimisation of far-reaching climate policies in Germany, to the integration of climate change into several civil protection and agricultural insurance schemes in Mexico. Moreover, resting on different forms of power, the securitisation of climate change has played a key role in constructing specific actors and forms of knowledge as legitimate as well as in shaping certain identities in the face of the dangers of climate change. From a normative perspective, neither of these political consequences is purely good or bad but highly ambiguous and necessitates a careful, contextual assessment

    Telemedicine visits in an established multidisciplinary central nervous system clinic for radiation oncology and neurosurgery (RADIANS) in a community hospital setting.

    Get PDF
    OBJECTIVE: To determine the impact of telemedicine visits, compared to in-person visits, on patient satisfaction in an established community hospital-based multidisciplinary central nervous system (CNS) clinic. METHODS: Telemedicine options - virtual visits and teleconferencing - were introduced in July 2020. Both radiation oncologist and neurosurgeon were simultaneously present for the telemedicine visit. Descriptive patient demographics, survey responses, and travel time and distance calculations were analyzed. Satisfaction score was compared to previously published data. RESULTS: A total of twenty-five telemedicine visits (n=22 video; n=3 phone) were completed since July 2020. Patient demographics are as follows: mean age was 59 years (range=22-81), women (9) and men (16), repeat telemedicine visits n=10, malignant CNS disease (17) and benign disease (5). Mean one-way distance traveled was 165.07 miles (median=114; range=0.8-358). Mean roundtrip travel time was estimated at 5h 5min. Mean telemedicine visit duration was 15.3 mins (range=4-46). Mean patient satisfaction score for telemedicine visits was 4.84. CONCLUSION: Patients who opted for the telemedicine visits found them just as effective as in-person visits, saving time and travel costs as well as ensuring patient safety during the current COVID-19 pandemic. The telemedicine visit platform facilitates the multidisciplinary clinic model and should be considered for more widespread utilization (Tab. 3, Fig. 1, Ref. 18)
    corecore