60 research outputs found
Two FDC envelopes celebrating the 12 Franc stamp
No full textI had not been aware of this Florian stamp. He was born in Sauve in Gard in 1755. Poor Florian. Even this celebration of him includes, in the prose under his portrait: "Author of lovely pastorals and especially of numerous fables, which rank him as the follower, even if from a great distance, of our own good La Fontaine" (italics mine). Perhaps the easiest scene to recognize on the fable composite has the monkey lecturing with a magic lanterne. The stamp itself classifies him as "Fabuliste Romancier Autour Dramatique.Two FDC envelopes celebrating the 12 Franc stamp from 1955 featuring a portrait of Florian. Both have a postmark "Premier Jour Sauve - Florian - 2 Avril 1955." One envelope features a duochrome bust of Florian. The other presents a full-color collection of scenes from his fables. $4 each from Loic Marchat, Villeurbanne, France, through eBay, Oct. 11, 05
Follicular Dendritic Cell-Specific Prion Protein (PrP) Expression Alone Is Sufficient to Sustain Prion Infection in the Spleen
Full text linkPrion diseases are characterised by the accumulation of PrP(Sc), an abnormally folded isoform of the cellular prion protein (PrP(C)), in affected tissues. Following peripheral exposure high levels of prion-specific PrP(Sc) accumulate first upon follicular dendritic cells (FDC) in lymphoid tissues before spreading to the CNS. Expression of PrP(C) is mandatory for cells to sustain prion infection and FDC appear to express high levels. However, whether FDC actively replicate prions or simply acquire them from other infected cells is uncertain. In the attempts to-date to establish the role of FDC in prion pathogenesis it was not possible to dissociate the Prnp expression of FDC from that of the nervous system and all other non-haematopoietic lineages. This is important as FDC may simply acquire prions after synthesis by other infected cells. To establish the role of FDC in prion pathogenesis transgenic mice were created in which PrP(C) expression was specifically "switched on" or "off" only on FDC. We show that PrP(C)-expression only on FDC is sufficient to sustain prion replication in the spleen. Furthermore, prion replication is blocked in the spleen when PrP(C)-expression is specifically ablated only on FDC. These data definitively demonstrate that FDC are the essential sites of prion replication in lymphoid tissues. The demonstration that Prnp-ablation only on FDC blocked splenic prion accumulation without apparent consequences for FDC status represents a novel opportunity to prevent neuroinvasion by modulation of PrP(C) expression on FDC
The practice of access pricing : telecommunications in the United Kingdom
Full text linkTelecommunications was the first network utility to be privatized in the United Kingdom. Drawing on 15 years'experience and discussion in the field, the author shows the economic principles of regulation in general and access pricing in particular that have been implemented. British Telecommunications (BT), formed as a public enterprise in 1980-81, was privatized in 1984. Since then the approaches to regulation have changed in three broad periods: the duoply, the transition to competition, and the recently introduced normalization phase. Dealing with each period, the author focuses on how the actual implementation of access charges are determined, at the same time providing background needed on regulatory intervention generally. Rather than follow the model of competition for a common infrastructure, Oftel [the Office of Telecommunications, the regulatory agency]has encouraged competition between alternative networks, which benefits customers but involves duplication of fixed costs. As a result of Oftel's approach, customers have seen their bills reduced 50 percent in real terms since privatization. It is difficult to know how much to attribute this remarkable result to technological progress (BT halved its workforce in the same period), to regulatory intervention (Oftel set string caps until 1997), or to competition (there are hundreds of players in the market). The author contends more weight should probably be given to the first two. Entrants have not achieved big market shares, if one considers the asymmetric regulation that has been in place for more than a decade. Indirectly, at least, competition benefited consumers by applying discipline to BT's behavior. Oftel's approach was interventionist until 1997, when it began trying to normalize the industry, as authority overseeing competition. The odds on complete deregulation are slight, and some controls on industry will remain. In the longer term, Oftel should especially monitor anticompetitive practices and collusive behavior among the bigger players (BT, CWC, and cellulator operators), The United Kingdom's interconnection experience demonstrates the complexity of the problem and its relationship to other topics, such as tariff rebalancing, access deficit, and universal service. Although a bit ad hoc, the recent incentive regulation, with a network cap based on proper accounting procedures and engineering models, may represent the best practice available today in the telecommunications industry, says the author.Public Sector Economics&Finance,Decentralization,Knowledge Economy,Economic Theory&Research,Payment Systems&Infrastructure,Public Sector Economics&Finance,Education for the Knowledge Economy,Knowledge Economy,Economic Theory&Research,ICT Policy and Strategies
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