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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The hypervelocity impact related aspects of Panspermia

Mann, Joanna January 2002 (has links)
No description available.
2

A PLACE AMONG THE STARS? THE INFLUENCE OF RELIGION AND CREATIONISM ON ATTITUDES TOWARDS SPACE EXPLORATION AND BELIEFS IN EXTRATERRESTRIAL LIFE

Schiavone, Sarah R. 01 January 2018 (has links)
Space exploration continues to expand humanity’s understanding of the universe. And, while Americans have widely favorable attitudes towards efforts to explore outer space, certain religious beliefs appear to be associated with more negative attitudes towards space exploration and the search for extraterrestrial life. The current study explored the role of religion and creationism on attitudes towards space exploration and the search for extraterrestrial life. Priming techniques were used to test whether increasing the accessibility of religious and creationist concepts led to more negative attitudes towards space exploration and beliefs about extraterrestrial life. Participants (N = 230) encountered an explicit prime of religion, creationism, or a control prior to completing a word fragment task and measures of attitudes towards space exploration and beliefs about extraterrestrial life. The results of Bayesian estimation and hypothesis testing did not support the prediction. However, exploratory analyses indicated very strong evidence of atheists having more positive attitudes towards space exploration and beliefs about extraterrestrial life than theists. These findings suggest that while priming religion and creationism did not appear to influence reported attitudes, attitudes towards space exploration and the search for extraterrestrial life may differ based on belief in god.
3

Assessing the formation and preservation of organic signatures in extreme environments in the context of the ExoMars 2020 rover mission

Reinhardt, Manuel 17 May 2019 (has links)
No description available.
4

FROM LIVING WORLD TO A DEAD EARTH:MARS IN AMERICAN SCIENCE SINCE THE SPACE AGE

Varga, Ian Jasper 29 April 2016 (has links)
No description available.
5

Debris disks from an astronomical and an astrobiological viewpoint

Cataldi, Gianni January 2013 (has links)
In this licentiate thesis, I consider debris disks from an observational, astronomical viewpoint, but also discuss a potential astrobiological application. Debris disks are essentially disks of dust and rocks around main-sequence stars, analogue to the Kuiper- or the asteroid belt in our solar system. Their observation and theoretical modeling can help to constrain planet formation models and help in the understanding of the history of the solar system. After a general introduction into the field of debris disks and some basic debris disk physics, the thesis concentrates on the observation of gas in debris disks. The possible origins of this gas and its dynamics are discussed and it is considered what it can tell us about the physical conditions in the disk and possibly about the dust composition. In this way, the paper associated with this thesis (dealing with the gas in the β Pic debris disk) is set into context. More in detail, we observed the CII emission originating from the carbon-rich β Pic disk with Herschel HIFI and attempted to constrain the spatial distribution of the gas from the shape of the emission line. This is necessary since the gas production mechanism is currently unknown, but can be constraint by obtaining information about the spatial profile of the gas. The last part of the thesis describes our preliminary studies of the possibility of a debris disk containing biomarkers, created by a giant impact on a life-bearing exoplanet.
6

Evaluation of techniques for handling luminescence in Raman spectroscopy for space application in regard to the search for extraterrestrial life / A comparison of five different methods for identifying space-relevant luminescent biological and mineralogical sample

Hanke, Franziska 18 February 2020 (has links)
Die Ramanspektroskopie (RS) ist eine analytische Technik, die in Folge einer optischen Anregung eines Stoffes materialspezifische Informationen über dessen molekulare Schwingungen und Kristallstruktur liefert. Da sowohl Minerale als auch biologische Materialien untersucht werden können, ist die RS in der Weltraumforschung von besonderem Interesse. So werden im Jahr 2020 gleich zwei Marsrover (ExoMars und Mars 2020) Ramanspektrometer mitführen, deren Aufgabe unter anderem die Detektion von Spuren von vergangenem oder gegenwärtigem extraterrestrischen Leben sein wird. Die Charakterisierung von stark lumineszierenden biologischen Proben und Mineralen stellt eine der größten Herausforderungen in der konventionellen RS dar. Daher beschäftigt sich diese Dissertation mit dem Problem der Lumineszenz in der RS. Dazu wird das Potenzial von fünf verschiedenen ramanspektroskopischen Techniken zur Handhabung der Lumineszenz evaluiert. Diese Techniken beinhalten (i) die Auswahl von verschiedenen Anregungswellenlängen (325 nm, 532 nm, 785 nm, 1064 nm), welche auf dem Konzept der spektralen Trennung des Lumineszenz- und Ramansignals basiert. (ii) Eine Alternative ist das Photobleichen, wobei die Lumineszenz durch eine lange Belichtungszeit unterdrückt wird. (iii) Eine weitere Methode für die spektrale Separation von Raman- und Lumineszenzphotonen ist die anti-Stokes RS. (iv) Bei der SERDS Technik werden zwei leicht verschobene Anregungswellenlängen verwendet. (v) Abschließend erfolgt die Untersuchung der Streu- und Emissionsstrahlung in der Zeitdomäne. Die Ergebnisse dieser Arbeit zeigen, dass es keine universelle Lösung gibt um das Problem der Lumineszenz in der RS zu überwinden. Allerdings weist die Verwendung unterschiedlicher Laserwellenlängen großes Potenzial für die erfolgreiche Handhabung der Lumineszenz in der RS auf. In Kombination mit SERDS und/oder Photobleichen steigt die Wahrscheinlichkeit verwertbare Spektren für die Probencharakterisierung zu erhalten. / Raman spectroscopy (RS) is an analytical technique conveying material-specific information about a material’s molecular vibrations and crystal structure in succession of an optical excitation of the material. Due to the fact that mineralogical as well as biological material can be examined, RS is of special interest for space research. For instance, two Mars rovers (ExoMars and Mars 2020) will each carry along a Raman spectrometer in the year 2020, with the aim of detecting inter alia traces of extant or extinct extraterrestrial life. One of the biggest challenges in conventional RS is the characterization of strongly luminescent biological or mineralogical material; therefore, the dissertation at hand deals with the problem of luminescence in RS. For this purpose, the potential of five different Raman spectroscopic techniques for the handling of luminescence will be evaluated. These techniques include (i) the selection of different excitation wavelengths (325 nm, 532 nm, 785 nm and 1064 nm), which is based on the concept of the spectral separation of the luminescence signals as well as Raman signals. (ii) Photobleaching provides an alternative whereby the luminescence is suppressed by long exposure. (iii) A further method for the spectral separation of Raman photons as well as luminescence photons is provided by the anti-Stokes RS. (iv) The SERDS technique uses two slightly shifted excitation wavelengths. (v) Finally the examination of inelastic scattering and emission takes place in the time domain. The results of this dissertation show that there is no universal solution to overcome the problem of luminescence in RS. However, the usage of different excitation wavelengths offers great potential for handling luminescence in RS successfully. In combination with SERDS and/or photobleaching the probability to obtain exploitable spectra for sample characterization increases
7

AI-paradoxen / The AI Paradox

Ytterström, Jonas January 2022 (has links)
Derek Parfit är kanske en av vår tids mest kända moralfilosofer. Parfit inleder sin första bok Reasons and Persons med att ställa frågan: vad har vi mest skäl att göra? Hans fråga berör vad som egentligen har betydelse, en fråga som han fortsätter att beröra i sin andra bok On What Matters. Filosofen Toby Ord argumenterar i sin bok The Precipice för att den utmaning som definierar vår tid, och bör ha en central prioritering, är utmaningen att skydda mänskligheten emot så kallade existentiella risker. En existentiell risk är en typ av risk som hotar att förstöra, eller förhindra, mänsklighetens långsiktiga potential. Ord menar att vi idag befinner oss vid en kritisk tidpunkt i mänsklighetens historia som kan vara helt avgörande för om det ens kommer existera en framtid för mänskligheten. Men om vi bör skydda mänskligheten emot existentiella risker, så kan en lämplig följdfråga vara i vilken ordning vi bör prioritera olika existentiella risker. Den svenske filosofen Nick Bostrom har liksom Ord länge förespråkat att existentiella risker bör tas på allvar. Han menar att preventiva åtgärder bör vidtas. I sin bok Superintelligens argumenterar Bostrom, både omfattande och väl, för att den existentiella risk som kan te sig som mest brådskande, och kanske allvarligast, är artificiell intelligens. Bostrom menar att vi har goda skäl att tro att utveckling av artificiell intelligens kan eskalera till den grad att mänsklighetens öde kan hamna bortom vår egen kontroll. Det han syftar på är att människan just nu är den dominerande agenten på jorden och därför innehar en stor kontroll, men att så inte alltid behöver vara fallet. Bostroms tes kunde te sig som okonventionell då den presenterades, men kan även te sig så idag vid en första anblick. Han har dock fått explicit medhåll av personer som Bill Gates, Stephen Hawking, Elon Musk, Yuval Noah Harari och Max Tegmark, som antingen håller med eller resonerar i liknande banor. Även jag själv finner Bostroms antaganden välgrundade. Slutsatsen som många drar är därför att vi bör betrakta artificiell intelligens som en existentiell risk som ska prioriteras högt. Jag kommer dock i denna text att argumentera för tesen att vi inte bör betrakta artificiell intelligens som en existentiell risk. Tesen följer från en invändning som jag kommer att kalla för AI-paradoxen. Det tycks enligt invändningen som att artificiell intelligens inte kan leda till en existentiell katastrof givet vissa premisser som flera i debatten om artificiell intelligens tycks acceptera. Texten i uppsatsen är strukturerad på följande sätt. I avsnitt 2 kommer jag att återge det övergripande argumentet som cirkulerar i debatten om artificiell intelligens som ett hot. I avsnittet kommer jag också förklara några viktiga termer och begrepp. I avsnitt 3 börjar jag med att titta på den första premissen i argumentet, samt resonera om dess rimlighet. I avsnitt 4 går jag sedan vidare till den andra premissen i argumentet och gör samma sak med den. Väl i avsnitt 5 så väljer jag att presentera min egen idé som jag kallar för AI-paradoxen, vilket är en invändning mot argumentet. I avsnitt 6 diskuterar jag sedan AI-paradoxens implikationer. Avslutningsvis, i avsnitt 7, så ger jag en övergripande sammanfattning och en slutsats, samt några sista reflektioner. / Derek Parfit is perhaps one of the most famous moral philosophers of our time. Parfit begins his first book Reasons and Persons by asking the question: what do we have most reason to do? His question touches upon what really matters, a question he continues to touch upon in his second book On What Matters. The philosopher Toby Ord argues in his book The Precipice that the challenge that defines our time, and should have a central priority, is the challenge of safeguarding humanity from so-called existential risks. An existential risk is a type of risk that threatens to destroy, or prevent, humanity’s longterm potential. Ord means that today we are at a critical time in the history of humanity that can be absolutely decisive for whether there will even exist a future for humanity. But if we are to safeguard humanity from existential risks, then an appropriate question may be in what order we should prioritize different existential risks. The Swedish philosopher Nick Bostrom, like Ord, has long advocated that existential risks should be taken seriously. He believes that preventive measures should be taken. In his book Superintelligence Bostrom argues, both extensively and well, that the existential risk that may seem most urgent, and perhaps most severe, is artificial intelligence. Bostrom believes that we have good reason to believe that the development of artificial intelligence can escalate to the point that the fate of humanity can end up beyond our own control. What he is referring to is that humans are currently the dominant agent on earth and therefore has great control, but that this does not always have to be the case. Bostrom's thesis may have seemed unconventional when it was presented, but it can also seem so today at first glance. However, he has been explicitly supported by people like Bill Gates, Stephen Hawking, Elon Musk, Yuval Noah Harari and Max Tegmark, who either agree or reason similarly. I myself also find Bostrom's assumptions well-founded. The conclusion that many draw is therefore that we should regard artificial intelligence as an existential risk that should be given a high priority. However, in this text I will argue for the thesis that we should not regard artificial intelligence as an existential risk. The thesis follows from an objection of my own, which I call the AI ​​paradox. According to the objection, it seems that artificial intelligence cannot lead to an existential catastrophe given certain premises that many in the debate about artificial intelligence as a threat seem to accept. The text in the essay is structured as follows. In section 2 I will present the main argument circulating in the debate about artificial intelligence as a threat. In the section I will also explain some important terms and concepts. In section 3 I begin by looking at the first premise in the argument, and also reason about its plausibility. In section 4 I proceed to the second premise in the argument and examine it similarly. Once in section 5 I choose to present my own idea, which I call the AI ​​paradox, which is an objection to the argument. In section 6 I discuss the implications of the AI ​​paradox. Finally, in section 7, I give an overall summary and a conclusion, as well as some last reflections.

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