Doctor of Philosophy / Department of History / David A. Graff / Cotton was the most important commodity in the economy of the industrialized Western world in the mid-nineteenth century, as vital then as petroleum is today. It was widely believed that a prolonged interruption of the cotton supply would lead not merely to a severe economic depression, but possibly to the collapse of Western Civilization. Three quarters of the world’s cotton supply came from the Southern states of the United States. When the American Civil War erupted and cotton supplies were cut off, the British Cotton Supply Association was faced with the difficult task of establishing cotton cultivation in other locations. In order for the effort to succeed, the British had to obtain and distribute millions of pounds of American cotton seeds. The United States government, the Illinois Central Railroad, and a number of organizations and individuals cooperated to obtain the necessary seeds that the British had to have. American farm equipment manufacturers assisted by designing, making, and distributing portable cotton gins and other implements needed by cotton growers overseas. U.S. consuls overseas sometimes assisted the Cotton Supply Association with seed and equipment distribution. This dissertation is about the implementation of the grand economic strategies of the United States and Great Britain. It is also about the people who implemented those strategies on the ground, people as diverse as Union agents who went into Confederate territory to procure cotton seeds, farmers in Illinois, British consuls who distributed seeds grown in Illinois to farmers in the Ottoman Empire, and English colonists who flocked to Fiji with high hopes of becoming cotton planters. It attempts to measure the impact of the cotton boom and subsequent bust that resulted from the American Civil War on societies around the world.

Obstructive sleep apnea (OSA) severity is strongly associated with the degree of overnight peripharyngeal fluid accumulation. We hypothesized that intravenous fluid loading would cause upper airway (UA) narrowing or increase the frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index; AHI). We employed a controlled, randomized double-crossover experiment in 9 healthy men aged 23-46 years. In the control, subjects were administered approximately 80 ml of normal saline intravenously during sleep. In the intervention, subjects were administered approximately 1850 ml of saline during sleep while wearing compression stockings to localize fluid rostrally. The intervention induced nuchal fluid accumulation, resulting in an increase in neck circumference (+0.1 cm during control, +0.6 cm during intervention, P< 0.01 ) and a decrease in UA cross-sectional area (-0.08 cm2 during control, -0.43 cm2 during intervention, P = 0.023). Although the intervention did not increase the AHI (control AHI = 19.5, intervention AHI = 30.3, P = 0.249), the AHI during the intervention correlated with age (r = 0.8, P < 0.01). Thus, intravenous saline loading during sleep can narrow the UA, which in older men may induce or worsen OSA. Further studies are needed to test this hypothesis.

Obstructive sleep apnea (OSA) severity is strongly associated with the degree of overnight peripharyngeal fluid accumulation. We hypothesized that intravenous fluid loading would cause upper airway (UA) narrowing or increase the frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index; AHI). We employed a controlled, randomized double-crossover experiment in 9 healthy men aged 23-46 years. In the control, subjects were administered approximately 80 ml of normal saline intravenously during sleep. In the intervention, subjects were administered approximately 1850 ml of saline during sleep while wearing compression stockings to localize fluid rostrally. The intervention induced nuchal fluid accumulation, resulting in an increase in neck circumference (+0.1 cm during control, +0.6 cm during intervention, P< 0.01 ) and a decrease in UA cross-sectional area (-0.08 cm2 during control, -0.43 cm2 during intervention, P = 0.023). Although the intervention did not increase the AHI (control AHI = 19.5, intervention AHI = 30.3, P = 0.249), the AHI during the intervention correlated with age (r = 0.8, P < 0.01). Thus, intravenous saline loading during sleep can narrow the UA, which in older men may induce or worsen OSA. Further studies are needed to test this hypothesis.

Das Hauptziel dieser Arbeit ist die Charakterisierung extrem starker Quellen, die höchstwahrscheinlich die kosmische Strahlung beschleunigen. In dieser Arbeit wurden VHE-Gammastrahlenbeobachtungen mit den MAGIC-Teleskopen verwendet, um die Eigenschaften von Blazaren zu untersuchen. Um die Mechanismen zu untersuchen, die zur Breitbandemission von Blazaren führen, wird ein stationärer lepto-hadronischer Code unter Verwendung eines einfachen semianalytischen Frameworks entwickelt. Daher implementiert der Code neben den leptonischen Wechselwirkungen auch die relevanten hadronischen Wechselwirkungskanäle: Protonensynchrotronstrahlung, Photo-Meson-Wechselwirkungen, Proton-Proton-Wechselwirkungen und Paarkaskaden. Die Dissertation präsentiert die Ergebnisse derMAGIC- und Multiwellenlängen-Monitoring-Kampagne des Blazars 1ES 1959 + 650 im Jahr 2016. Im Jahr 2016 durchlief die Quelle eine äußerst aktive Phase und zeigte am 13. Juni, 14. Juni und 1. Juli 2016 drei bemerkenswert helle VHE-Gammastrahlenfackeln. Um die Breitbandspektren der Quelle während der bemerkenswerten Fackelaktivitäten zu untersuchen, wurden drei verschiedene theoretische Modelle übernommen: leptonisch, hadronisch und gemischt lepto-hadronisch. Sowohl das hadronische als auch das gemischte leptohadronische Modell ergaben während der intensiven Aktivitätsperiode Neutrinoflüsse, die unter der Empfindlichkeit der gegenwärtigen Generation von Neutrinoteleskopen liegen. Die Beobachtung eines hochenergetischen Neutrinos durch IceCube im räumlichen und zeitlichen Zusammentreffen mit einem aufflammenden Blazar mit dem Namen TXS 0506 + 056 ergab 2017 erstmals Hinweise auf Identifizierung einer extragalaktischen kosmischen Strahlenquelle. Die Modellierung der elektromagnetischen Daten und des vorhergesagten Neutrinoflusses impliziert, dass die Quelle tatsächlich ein potenzieller Neutrinostrahler und damit ein Beschleuniger für energiereiche kosmische Strahlen sein könnte. / The main aim of this thesis is to characterize extremely powerful sources that are most likely accelerating cosmic rays. Cosmic-ray sources are also believed to produce photons and neutrinos that act as direct tracers of their sources of origin. In this thesis VHE gamma-ray observations by the MAGIC telescopes were used to study the properties of blazars. To investigate the mechanisms giving rise to the broadband emission from blazars, a stationary lepto-hadronic code is developed using a simple semi-analytical framework. Hence along with the leptonic interactions, the code also implements the relevant hadronic interaction channels: proton synchrotron radiation, photo-meson interactions, proton-proton interactions and pair cascades. The thesis presents the results from theMAGIC and multi-wavelength monitoring campaign of the blazar 1ES 1959+650 during 2016. In 2016 the source underwent into an extremely active phase and exhibited three remarkably bright VHE gamma-ray flares on 13th June, 14th June and 1st July of 2016. On two of these nights, signs of rapid flux variability within sub-hour timescales was clearly resolved by the MAGIC observations. In order to investigate the broadband spectra of the source during the remarkable flaring activities, three different theoretical models were adopted: leptonic, hadronic and mixed lepto-hadronic. Both the hadronic and mixed leptohadronic models yielded neutrino fluxes during the intense activity period, that falls below the sensitivity of the current generation of neutrino telescopes. In 2017, the observation of a high-energy neutrino by IceCube in spatial and temporal coincidence with a flaring blazar named TXS 0506+056 yielded for the first time, hints towards identification of an extragalactic cosmic-ray source. The modelling of the electromagnetic data and the predicted neutrino flux implies that the source could indeed be a potential neutrino emitter and hence an accelerator of high-energy cosmic rays.

Blazars are a type of Active Galaxy that emit strong astrophysical jets. The association of a HE gamma-ray flare from the blazar TXS 0506+056 to the IceCube-170922A neutrino event in 2017, opened the possibility to a link between these two events. In this thesis, we will look at the HE gamma-ray behavior of TXS 0506+056 using data obtained from the Fermi-LAT by taking into account the other set of neutrino events associated with this source from 2014-2015. We will investigate whether both neutrino events present with comparable HE gamma-ray behavior by analyzing the lightcurves and the spectra for a quiet state, the 2014-2015 period, and the flare centered around the neutrino event from 2017. The results of the analysis performed in this thesis show no strong indication of a change in the gamma-ray behaviour in these potential neutrino detections.

Im Jahr 2013 ist es dem IceCube-Experiment gelungen, einen Fluss von Neutrinos extraterrestrischen Ursprungs nachzuweisen, und damit das Neutrino als weiteres kosmisches Botenteilchen zu etablieren. Die Frage nach dem Ursprung der Neutrinos, die einen komplementären Blick auf die Quellen bieten, kann möglicherweise die alte Frage nach dem Ursprung der kosmischen Strahlung lösen. Zeitunabhängige Suchen nach Neutrinoquellen konnten bisher keine einzelnen Kandidaten isolieren. Zeitlich veränderliche Quellen kommen daher als Ursprung in Betracht. IceCube ermöglicht es, kontinuierlich den gesamten Himmel nach aufflackernden Neutrinoquellen abzusuchen und die astronomische Gemeinschaft schnellstmöglich zu benachrichtigen. In dieser Arbeit wird die Echtzeitidentifikation und -rekonstruktion von Myonneutrinokandidaten mit IceCube verbessert. Die erreichte Sensitivität ist mit etablierten nicht-Echtzeit Analysen vergleichbar. Kontinuierlich vom Experiment am Südpol übermittelte Informationen werden sofort auf bemerkenswerte Ereignisse hin analysiert. Bekannte astrophysikalische Quellen von Gammastrahlung werden auf Neutrinoemission hin beobachtet. Eine verallgemeinerte Methode erlaubt die Suche nach Signalen überall, unbeeinflusst von vorher bekannten Quellen. Weiterhin werden die hochenergetischsten Neutrinokandidaten, die wahrscheinlich astrophysikalischen Ursprungs sind, sofort identifiziert und global bekannt gemacht. Abschließend werden die Suchalgorithmen am Beispiel zweier Blazare demonstiert, 1ES 1959+650 und TXS 0506+56. In letzterem Fall wurden erstmals Anzeichen für eine Quelle hochenergetischer, kosmischer Neutrinos gefunden. Die im Rahmen dieser Arbeit entwickelte Infrastruktur erlaubt es, die astronomische Gemeinschaft auf signifikante Neutrinoereignisse, oder sich entwickelnde Neutrinocluster hinzuweisen. Auch die zügige Suche nach Neutrinos in Reaktion auf interessante astrophysikalische Ereignisse, wie z.B. Gravitationswellen, ist möglich. / The discovery of an flux of neutrinos of astrophysical origin with the IceCube experiment in 2013 has broadened our understanding of cosmic messengers and opened a new window on the universe. By addressing the newly pertinent question about their sources, neutrinos can provide a complementary view on cosmic accelerators and may help solving the long-standing puzzle of the origin of the cosmic rays. As traditional time-integrated searches for sources of neutrinos have not been able to isolate individual candidates, variable and transient sources shift into focus. IceCube's design allows to continuously search the entire sky for neutrino flares, and alert the community with the lowest possible latency in the case of a detection. This thesis improves the identification and reconstruction of muon neutrino candidates with IceCube in real-time, achieving a sensitivity comparable to dedicated offline analyses. The stream of neutrino candidates is analyzed for interesting events in order to alert partner experiments and inspire follow-up observations. First, known gamma-ray emitters are monitored for time-variable neutrino emission. Second, a generalization of this method monitors the entire sky for neutrino flares, regardless of pre-defined source lists. Third, the most-energetic neutrino candidates with the highest chance to be of astrophysical origin are selected for alerts. Eventually, the search methods are applied to the blazars 1ES 1959+650 and TXS 0506+056. In the latter case, evidence for source of high-energetic, astrophysical neutrinos was found for the first time. The infrastructure built in this work allows to notify the community whenever significant neutrino events are recorded, or significant flares develop on time-scales from days to weeks. It also allows to quickly perform neutrino follow-up searches in response to interesting astrophysical events, such as the observation of gravitational waves.