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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.
21

Regulation and Investment in Next Generation Access Networks: Recent Evidence from the European Member States

Briglauer, Wolfgang, Ecker, Georg, Gugler, Klaus January 2011 (has links) (PDF)
Fiber-deployment of future telecommunications networks ("Next Generation Access" - NGA) is currently a major challenge for sector-specific regulators as well as for investing firms. Although the future socio-economic importance of new telecommunications networks is uncontroversial, the related investment activities vary substantially in international comparison. This work intends to identify the most important determinants of previous NGA deployment using data from the EU27 member states for the years 2005 to 2010. For our analysis, we employ latest data on NGA deployment, relevant competition and regulatory indicators as well as other supply and demand side controls. Our econometric model incorporates: i) aggregated country level data; ii) structurally modeled dynamics of the deployment process which allows us to disentangle long-term and short-term effects; finally, iii) we argue that there is no endogeneity problem with respect to investment activities and regulation since we refer to regulation in preceding broadband markets. For our econometric analysis, we employ several dynamic panel data methods, such as GMM and LSDVC. Our results indicate that stricter previous broadband access regulation has a negative impact on NGA deployment. As regards the dynamics of the adjustment process, we find that there are severe adjustment costs and stickiness towards the desired long-term level of NGA infrastructure. (author's abstract) / Series: Working Papers / Research Institute for Regulatory Economics
22

The Impact of Regulation and Competition on the Adoption of Fiber-based Broadband Services: Recent Evidence from the European Member States

Briglauer, Wolfgang 01 1900 (has links) (PDF)
Although fibre-deployment of next generation access (NGA) broadband networks is considered as a decisive development for any information-based society, investment activities and especially the adoption of fiber-based broadband services take place only very gradually in most countries. This work identifies the most important determinants of NGA broadband adoption, using most recent panel data from the European Union member states (EU27) for the years from 2004 to 2012. The results show that stricter previous broadband access regulation has a negative impact on NGA adoption, while competitive pressure from mobile networks affects NGA adoption in a non-linear manner. It appears that the approach of strict cost-based access regulation embedded in the EU regulatory framework is at odds with the ambitious targets outlined in the European Commission´s "Digital Agenda". Finally, we find strong evidence for network effects underlying the NGA adoption process. (author's abstract) / Series: Working Papers / Research Institute for Regulatory Economics
23

The Impact of Regulation and Competition on the Adoption of Fiber-based Broadband Services: Recent Evidence from the European Member States

Briglauer, Wolfgang 01 1900 (has links) (PDF)
Fibre deployment of next-generation high-speed broadband networks is considered to be a decisive development for any information-based society, yet investment activities and especially the adoption of fibre-based broadband services take place only very gradually in most countries. This work identifies the most important determinants of the adoption of fibre-based broadband services, using the most recent panel data from the European Union member states (EU27) for the years from 2004 to 2012. The results show that the stricter previous broadband access regulation has a negative impact on adoption, while competitive pressure from mobile networks affects adoption in a non-linear manner. It appears that the approach of strict cost-based access regulation embedded in the EU regulatory framework is at odds with the targets outlined in the European Commission's "Digital Agenda". Finally, we also find strong evidence for network effects underlying the adoption process. (author's abstract) / Series: Working Papers / Research Institute for Regulatory Economics
24

Dynamics of the British Ice Sheet and prevailing hydrographic conditions for the last 175,000 years : an investigation of marine sediment core MD04-2822 from the Rockall Trough

Hibbert, Fiona Danielle January 2011 (has links)
This study presents a stratigraphic investigation of the marine sediment core MD04-2822 from the Rockall Trough (56° 50.54' N, 11° 22.96' W; 2344 m water depth). This core is currently the only available high resolution record for the calibration of Late Quaternary sedimentary sequences of the British (Hebridean) margin. It therefore offers an unprecedented archive of changing sedimentological and climatological conditions for the last 175,000 years. The high resolution, multi-proxy records have enabled surface and deep water conditions within the Rockall Trough to be reconstructed. In addition, the fluctuating nature of ice-rafted debris (IRD) inputs to the MD04-2822 site allows a first order attempt of BIS dynamics for the entirety of the last glacial period (i.e. from the demise of the last interglacial to the decay of the Devensian/Weichselian ice sheet) as well as the majority of the penultimate (Saalian/MIS 6) glaciation. Sediment core MD04-2822 is ideally located to capture the dynamics of the British Ice Sheet (BIS) via a continuous record of IRD and fine-grained terrigenous inputs. Fundamental to this is the construction of a robust chronology. This was achieved via: the correlation of the benthic δ¹⁸O record to a global δ¹⁸O stack (SPECMAP); the correlation of the surface proxies (% N. pachyderma (sinistral) and XRF Ca) to the Greenland δ¹⁸O and Antarctic methane ice core records; and radiocarbon dating. This chronology was validated using both radiocarbon dating and tephra horizons. An evaluation of the event stratigraphy approach used in the construction of the MD04-2822 chronology is presented. The marine record provides a valuable archive of past ice sheet dynamics as much terrestrial evidence is removed or obscured by subsequent ice sheet oscillations MD04-2822 provides the first evidence for the expansion of the BIS onto the Hebridean Margin during MIS6 (thereby confirming previous long-range seismic correlations). The continuous sedimentation at MD04-2822 enabled the first insights into the early dynamics of the last BIS. Increases in IRD and fine grained terrigenous material delivered to the MD04-2822 at ca. 72 kyr represent the first significant delivery of material from the BIS across the continental shelf to the core site. The BIS would therefore have attained a marine calving margin by this time. A multi-proxy investigation of provenance was undertaken, however unequivocal provenance determinations remain problematic. The location of the core suggest the proximal BIS as the most likely source of terrigenous inputs. The expanded nature of the MD04-2822 sediments during the penultimate deglacial (Termination II) provides the first details of BIS dynamics for this period: the interplay of large inputs of freshwater from the decay of the Saalian (MIS 6) ice sheets (including the BIS) upon the surface and deep water circulation of the North Atlantic is investigated. In addition, sub-orbital climatic variability is documented at this location throughout the last interglacial (MIS 5e) and appears to be an intrinsic feature of both the N.E. Atlantic surface and deep water circulation of the last 175 kyr.
25

Insertion of Basic Amino Acids in the Hemagglutinin Cleavage Site of H4N2 Avian Influenza Virus (AIV)—Reduced Virus Fitness in Chickens is Restored by Reassortment with Highly Pathogenic H5N1 AIV

Gischke, Marcel, Ulrich, Reiner, Fatola, Olanrewaju I., Scheibner, David, Salaheldin, Ahmed H., Crossley, Beate, Böttcher-Friebertshäuser, Eva, Veits, Jutta, Mettenleiter, Thomas C., Abdelwhab, Elsayed M. 01 February 2024 (has links)
Highly pathogenic (HP) avian influenza viruses (AIVs) are naturally restricted to H5 and H7 subtypes with a polybasic cleavage site (CS) in hemagglutinin (HA) and any AIV with an intravenous pathogenicity index (IVPI) ≥ 1.2. Although only a few non-H5/H7 viruses fulfill the criteria of HPAIV; it remains unclear why these viruses did not spread in domestic birds. In 2012, a unique H4N2 virus with a polybasic CS 322PEKRRTR/G329 was isolated from quails in California which, however, was avirulent in chickens. This is the only known non-H5/H7 virus with four basic amino acids in the HACS. Here, we investigated the virulence of this virus in chickens after expansion of the polybasic CS by substitution of T327R (322PEKRRRR/G329) or T327K (322PEKRRKR/G329) with or without reassortment with HPAIV H5N1 and H7N7. The impact of single mutations or reassortment on virus fitness in vitro and in vivo was studied. Efficient cell culture replication of T327R/K carrying H4N2 viruses increased by treatment with trypsin, particularly in MDCK cells, and reassortment with HPAIV H5N1. Replication, virus excretion and bird-to-bird transmission of H4N2 was remarkably compromised by the CS mutations, but restored after reassortment with HPAIV H5N1, although not with HPAIV H7N7. Viruses carrying the H4-HA with or without R327 or K327 mutations and the other seven gene segments from HPAIV H5N1 exhibited high virulence and efficient transmission in chickens. Together, increasing the number of basic amino acids in the H4N2 HACS was detrimental for viral fitness particularly in vivo but compensated by reassortment with HPAIV H5N1. This may explain the absence of non-H5/H7 HPAIV in poultry.
26

Insertion of Basic Amino Acids in the Hemagglutinin Cleavage Site of H4N2 Avian Influenza Virus (AIV): Reduced Virus Fitness in Chickens is Restored by Reassortment with Highly Pathogenic H5N1 AIV

Gischke, Marcel, Ulrich, Reiner, Fatola, Olanrewaju I., Scheibner, David, Salaheldin, Ahmed H., Crossley, Beate, Böttcher-Friebertshäuser, Eva, Veits, Jutta, Mettenleiter, Thomas C., Abdelwhab, Elsayed M. 02 February 2024 (has links)
Highly pathogenic (HP) avian influenza viruses (AIVs) are naturally restricted to H5 and H7 subtypes with a polybasic cleavage site (CS) in hemagglutinin (HA) and any AIV with an intravenous pathogenicity index (IVPI) 1.2. Although only a few non-H5/H7 viruses fulfill the criteria of HPAIV; it remains unclear why these viruses did not spread in domestic birds. In 2012, a unique H4N2 virus with a polybasic CS 322PEKRRTR/G329 was isolated from quails in California which, however, was avirulent in chickens. This is the only known non-H5/H7 virus with four basic amino acids in the HACS. Here, we investigated the virulence of this virus in chickens after expansion of the polybasic CS by substitution of T327R (322PEKRRRR/G329) or T327K (322PEKRRKR/G329) with or without reassortment with HPAIV H5N1 and H7N7. The impact of single mutations or reassortment on virus fitness in vitro and in vivo was studied. Ecient cell culture replication of T327R/K carrying H4N2 viruses increased by treatment with trypsin, particularly in MDCK cells, and reassortment with HPAIV H5N1. Replication, virus excretion and bird-to-bird transmission of H4N2 was remarkably compromised by the CS mutations, but restored after reassortment with HPAIV H5N1, although not with HPAIV H7N7. Viruses carrying the H4-HA with or without R327 or K327 mutations and the other seven gene segments from HPAIV H5N1 exhibited high virulence and ecient transmission in chickens. Together, increasing the number of basic amino acids in the H4N2 HACS was detrimental for viral fitness particularly in vivo but compensated by reassortment with HPAIV H5N1. This may explain the absence of non-H5/H7 HPAIV in poultry.
27

Essays on Fiscal Policy and the Support for Economic Reform in Emerging Europe

Eller, Markus 17 June 2011 (has links) (PDF)
This doctoral thesis addresses in a sequence of five essays the question how fiscal policy and economic output are interrelated in emerging Europe and how this relationship is shaped by the respective politico-economic environment and the individual-level support for economic reforms. Following main findings can be highlighted: (1) Countries in Central, Eastern and Southeastern Europe (CESEE) respond to a fiscal expansion in the euro area with fiscal easing at home, while the GDP response is mixed across countries.(2)Automatic fiscal stabilizers are comparatively small and discretionary fiscal policy has been largely pro-cyclical in CESEE. (3) The public spending and revenue structure is more "growth-friendly" in CESEEthan in the EU-15. (4) In transition economies with more democratic institutions and a better quality of governance, individuals with high market-relevant skills show a significantly larger support of the privatization status quo than individuals with low market skills. (5) The society in Russia - triggered by a lack of social capital - chooses to demand more state regulationand tolerate corruption to reduce negative externalities imposed by private business.(author's abstract)

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