The thermal accommodation coefficients of helium, neon, and argon on surfaces

Measurements of the accommodation coefficients of helium, neon, and argon on an ice surface at 77ºK were accomplished; Measurements of the accommodation coefficients of helium and neon on a clean tungsten surface are also reported here; These data are compared with theoretical calculations of accommodation coefficients as well as with data from other experimental studies --Abstract, pages iii-iv

The gamma-ray energy spectrum of the active galaxy Markarian 421

This is a study of the very high energy gamma-ray emission from Markarian 421. The data were taken by the Whipple Observatory 10 meter imaging atmospheric Cherenkov telescope (IACT) during the 1995/96 observing season. A method of extracting energy spectra using data obtained from IACTs has been previously developed at Iowa State University. This method is reviewed in the context of finding the spectrum of the Crab Nebula, the standard candle of very high energy gamma-ray astronomy. One important quantity that sets the energy scale of the Whipple 10 meter telescope is the electronic gain. This quantity has been determined by a direct measurement of the telescope electronics and by scaling previously measured values to the current observing season. Once the spectrum of the Crab Nebula during the 1995/96 observing season is found, the method is then applied to the Markarian 421 data. Of particular interest is a very intense flare observed on 7 May 1996. After the energy spectrum during the flare is found, I extend the method to investigate the high energy end of the spectrum. DeJager, Stecker and Salamon predict that the spectrum of Markarian 421 will cutoff between 1-10 TeV due to absorption by extragalactic background light. No cutoff is observed from the flare up to 6 TeV where statistics run out. Instead, the derived spectrum is more consistent with that predicted by MacMinn and Primack which gradually steepens between 0.3-10 TeV and then cuts off above 10 TeV. Energy spectra were found from the rest of the 1995/96 Markarian 421 data after dividing the data into periods of high and low emission. The low state spectrum is slightly steeper than the high state spectrum. However the difference, because of the limited number of photons collected during the low periods, is not statistically significant, being only 1.2[sigma]

Investigations into interferon response of novel bat cell cultures upon alphavirus infection

Bats have been identified as reservoir for human pathogenic zoonotic viruses like Rabies, Marburg or Henipaviruses. The fact that bats carry viruses without showing clinical symptoms, raised the question if these flying mammals have evolved specific mechanisms to suppress virus replication. To address this question a bat cell culture model was established to investigate the IFN response upon virus infection. First, cell lines of E. helvum, Epo. buettikoferi and R. aegyptiacus were generated, immortalised and characterized. IFN sensitivity upon viral and artificial IFN-stimuli was analysed by pan-bat IFN real-time RT-PCR assay. To enable comparative analysis of species-specificity and inter-species bioactive IFN secretion the VSV-bioassay was optimized. It was adapted to each cell line and the pan-species IFN enabled with the EC50 factor the determination of relative secreted bioactive IFN concentration. To determine IFN-signalling, the mRNA expression levels of several IFN stimulated genes (ISGs) were determined with established species-specific real-time RT-PCR assays. These methods enabled comparable studies between bat, murine and human cell lines. The role of bats within the life cycle of arthropod borne alphaviruses is not clear. The prevalence of cross-reactive antibodies was determined by an Immunofluoresence assay, analysing bat sera from several continents and species. In average 5% of the serological samples were found positive which is a comparably low seroprevalence. Interestingly, some Old World bat samples showed exclusive reactivity with New World alphaviruses and vice versa. This cross-reactivity might indicate that the phylogenetic range of alphaviruses in bats could be much higher. In an alphavirus infection model with O´nyong-nyong virus (ONNV) high IFN-induction on mRNA level was detected in all cell lines. Conversely, IFN secretion was reduced. Although IFN-signalling seemed to be more sensitive on mRNA expression level in bat cell lines, this could not be confirmed on protein levels. These results indicated a translational rather than a transcriptional shutoff upon alphavirus infection in bat cell lines. To investigate if these results were ONNV-specific, two additional alphaviruses, Sindbis and Chikungunya virus (SINV and CHIKV), were tested. These infection experiments showed similar results suggesting a general mechanism of alphaviruses to antagonize the IFN response. Interestingly, bat cell lines showed similar IFN response as human cell lines. Generated bat cell lines, designed pan-bat or species-specific real-time RT-PCR assays and the optimized VSV-bioassay altogether enable a detailed analysis of the IFN response to virus infections in bat cell lines, which was especially on the bioactive IFN protein level in this comparable way not possible before.Untersuchungen der Interferonantwort in neuen Fledertierzellkulturen nach Alphavirusinfektionen Fledermäuse wurden als Wirte von zoonotischen, humanpathogenen Viren, wie Tollwut, Marburg- oder Henipaviren, identifiziert. Als Träger von pathogenen Viren zeigen die Fledermäuse keine klinischen Symptome einer Erkrankung. Daher wurde spekuliert, ob sie im Laufe der Evolution spezielle Mechanismen zur Unterdrückung der Virusreplikation entwickelt haben. Zur Verifizierung dieser Frage, wurde die IFN-Antwort, bestehend aus IFN-Induktion, -Sezernierung und -Signalwirkung, auf Virusinfektionen in Fledermauszellen im Vergleich zu murinen und humanen Zellkulturmodellen untersucht. Zunächst wurden Zellkulturen von E. helvum, Epo. buettikoferi und R. aegyptiacus generiert, immortalisiert und charakterisiert. Mit Hilfe eines pan-spezies IFN Real-Time RT-PCR Assays konnte gezeigt werden, dass die generierten Fledermauszelllinien in der Lage sind, sowohl auf virale als auch auf artifizielle IFN-Stimuli zu reagieren. Die Optimierung des VSV-Bioassays ermöglicht die Detektion von sezerniertem IFN unter Berücksichtigung der Spezienspezifität und Interspezifität. Dazu wurde das Assay individuell an jede Zelllinie angepasst und mit Hilfe des EC50-Faktors die Vergleichbarkeit der Konzentration des sezernierten IFNs ermöglicht. Zur Bestimmung der IFN-Signalwirkung wurden verschiedene ISG mRNA- Expressionen mittels Spezies-spezifischen Real-Time RT-PCR Assays bestimmt. Durch die Entwicklung der entsprechenden Assays war es möglich, vergleichende Experimente durchzuführen. Ob Fledermäuse ebenfalls als Wirte für Alphaviren in Frage kommen, wurde bisher nur vermutet. Mit Hilfe einer serologischen Studie wurde daher die Prävalenz von kreuzreagierenden Antikörpern gegen Alphaviren in Fledermäusen verschiedenster Kontinente bestimmt. Es wurde eine Prävalenz von durchschnittlich 5% festgestellt. Dies ist eine vergleichsweise niedrige Seroprävalenz. Einige Altweltfledermausproben waren interessanterweise nur für Neuweltalphaviren positiv und umgekehrt. Dies lässt vermuten, dass die phylogenetische Spanne innerhalb der Alphaviren in Fledermäusen größer ist, als bis jetzt angenommen. In einem Alphavirusinfektionsmodell konnte gezeigt werden, dass die Infektion mit ONNV in allen Zellen eine hohe IFN-Induktion zur Folge hatte. Kontrovers hierzu konnte eine Reduktion der IFN-Sezernierung gemessen werden. Obwohl die IFN-Signalwirkung bei Fledermäusen auf mRNA-Ebene sensibler zu sein schien, konnte dies auf Proteinebene nicht bestätigt werden. Daher kann auch bei Fledermäusen auf einen Translationsabbruch nach Alphavirusinfektion geschlossen werden. Zur Klärung, ob die Ergebnisse ONNV-spezifisch waren, wurden die gleichen Versuche noch mit zwei weiteren Alphaviren (SINV und CHIKV) durchgeführt. Die Ergebnisse hieraus bestätigen, dass Fledermauszellen eine der humanen ähnliche IFN-Antwort besitzen und die beobachteten Mechanismen wahrscheinlich allgemeingültig für Alphaviren sind. Künftig kann also die IFN-Antwort auf Virusinfektionen zwischen Fledermaus- und humanen Zelllinien vergleichend auf allen Ebenen untersucht werden. Die generierten Zelllinien, die entwickelten Spezies-spezifischen Real-Time RT-PCR Assays und das optimierte VSV-Bioassay ermöglichen im Zusammenspiel detaillierte Erkenntnisse über die IFN-Antwort der Fledermauszellen auf Virusinfektionen, die im Besonderen auf der bioaktiven Proteinebene noch nahezu unerforscht ist

Job loss, firm-level heterogeneity and mortality:Evidence from administrative data

This paper estimates the effect of job loss on mortality for older male workers with a strong labor force attachment. Using Dutch administrative data, we find that job loss due to firm closure increased the probability of death within five years by a sizable 0.60 percentage points. Importantly, this effect is estimated using a model that controls for firm-level worker characteristics, such as lagged firm-level annual average mortality rates. On the mechanism driving the effect of job loss on mortality, we provide evidence for an effect running through stress and changes in life style

De ruimtelijke volwassenwording van de Hollandse stad (1200-1450): Een vergelijkende analyse van het ontstaan van de contouren van de Randstad aan de hand van stadsplattegronden

In the eleventh, twelfth and thirteenth century the Dutch landscape underwent a major spatial transformation. In a relatively short space of time, large areas of hitherto inaccessible peatland were reclaimed and made suitable for agriculture and habitation. In the thirteenth and fourteenth century this was quickly followed by urbanisation. The urbanisation process was remarkably rapid, and a great deal has already been written about the growth of Dutch towns. However, the emphasis has mainly been on administrative, economic and social changes during this period. Studies of the spatial dimension, especially comparative ones, have been rare.Het Hollandse landschap vertoonde in de elfde, twaalfde en dertiende eeuw een grote ruimtelijke dynamiek. In betrekkelijk korte tijd werden grote delen van het ontoegankelijke veen ontgonnen en geschikt gemaakt voor landbouw en bewoning. In de dertiende en veertiende eeuw vond vervolgens een proces van verstedelijking plaats. De snelheid waarmee dat gebeurde was opzienbarend, en over de groei van het aantal steden en de omvang ervan is dan ook al veel geschreven. De aandacht ging daarbij vooral uit naar de bestuurlijke, economische en sociale omslag in deze periode. Studies naar de ruimtelijke dimensie, zeker in vergelijkend perspectief, zijn echter schaars

Judicial deference to the executive branch at the State Court level

A study in the effects of the solicitor general on judicial deference to the executive branch at the state court level. There has been significant research done into the development of judicial deference, but it almost always takes place at the Supreme Court. Similarly, the Solicitor General’s success rate has only been analyzed at the federal level. Recently there has been a trend of states creating Solicitor General Offices in order to gain the advantage perceived at the federal level. By comparing the level of deference state courts give to their executive branch over two time periods I determine that although the Solicitor General does impact deference, the impact isn’t immediate. The states with the strongest level of deference were the states that have had Solicitor Generals for a significant amount of time before the analysis. States where the office was created I between the two time periods do experience heightened deference, but at a lower level. This paper seeks to fill the gap in judiciary research where the majority of the focus is on the Supreme Court, which although very important does not give a comprehensive understanding of the US judicial branch

Chapter 6 Coordinating international interventions in complex settings

This paper assesses coordination as a salient capability of international interventions in complex settings characterised by weak states, the dominance of political elites whose interest in reforms is questionable and multiple local and international stakeholders. It focuses on the challenge of integrating a range of national and international actors and multiple policy domains, assessing this operational capability in terms of a Whole-of-Society approach. Using the example of the EU’s intervention in Kosovo through the mechanisms of the EULEX mission, and the EU-facilitated Dialogue between Serbia and Kosovo, the paper argues that the EU’s impact in Kosovo was weakened by its limited ability to include and engage a broad range of local stakeholders. While a Whole-of-Society approach could address this weakness, the paper also argues that a better understanding of the context-specific opportunities and limitations placed on international organisations like the EU is needed