The Growth of Networking

Connections were made between institutions via telephone lines and these were of varying speeds and reliability, essentially according to the tariff paid for them. The cheap and cheerful connection was basically an ordinary 300-baud telephone line that enabled the user to operate a terminal as if present in the terminal room of the machine but, of course, with a much slower response time than if actually present. Faster lines were available, up to 1900 

But the developments in the UK were ad hoc and rather disorganised, and this was recognised by the Computer Board which, in 1973, set up a networking committee under the chairmanship of Prof. M. (Mike) Wells Leeds University and among whose members were Mervyn Williams (formerly of the Post Office), Roland Rosner (RAL), and Chris Morris (Bristol University). They reported to the Computer Board in 1974, recommending that a national network be set up and that its development be supervised by a six-person Joint Network Team (JNT). Although the report was accepted, these developments did not come about until 1979, and the proposed network, eventually called JANET (Joint Academic Network), did not come into full service until 1 April 1984. 

There were also changes on the national telecommunications (telecomms) scene. The Post Office had developed an experimental packet-switched system for data transmission, known therefore as EPSS, which became available in 1975. With the development of Packet Assembler-Disassemblers (PADs), the existing ad hoc system of networking became somewhat more organised, and started to use standard protocols. Intramural communications also tended to become packet based. 

Thus although the more traditional computational chemists stayed with punched cards or tape and preferred to run their programs in as hands-on a manner as possible until the end of the decade, the carnival was over. Where the user was geographically in relation to where the computer was had less and less relevance, as the decade progressed, to what could actually be accomplished. By the end of the decade too electronic mail (e-mail) had begun to make an impact on how people operated and interacted. 

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The description of a network structure is based on such parameters as chemical crosslink density and functionality, average chain length between crosslinks and length distribution of these chains, concentration of elastically active chains and structural defects like unreacted ends and elastically inactive cycles. However, many properties of a network depend not only on the above-mentioned characteristics but also on the order of the chemical crosslink connection — the network topology. So, the complete description of a network structure should include all these parameters. It is difficult to measure many of these characteristics experimentally and we must have an appropriate theory which could describe all these structural parameters on the basis of a physical model of network formation. At present, there are only two types of theoretical approaches which can describe the growth of network structures up to late post-gel stages of cure. One is based on tree-like models as developed by Dusek7 I0-26,1 The other uses computer-simulation of network structure on a lattice this model was developed by Topolkaraev, Berlin, Oshmyan 9,3l) (a review of the theoretical models may be found in Ref.7) and in this volume by Dusek). Both approaches are statistical and correlate well with experiments 6,7 9 10 13,26,31). They differ mainly mathematically. However, each of them emphasizes some different details of a network structure. 

At relative low pH, condensation rates are proportional to the [H ] concentration but because of low solubility rates of silica ( pH 2] (isoelectric point of silica pH 2.2), precipitation occurs. Formation and aggregation of primaiy silica particles occur together and contributes little to the growth of network. Thus developing gel network consists of extremely small primary particles, not exceeding 2 nm in diameter [37]. 

Arteriogenesis is the growth of collateral vessels from a pre-existing arteriolar network to bypass an ischemic area (e.g., following cardiac ischemia). 

Health maintenance organizations are the most restrictive type of managed care organization, and consumer dissatisfaction with restricted choice in HMOs likely was a significant factor in the growth of point of service (POS) plans. POS plans sometimes are referred to as open-ended HMOs. Like HMOs, enrollees typically select a primary care provider and pay no fee or a small copayment to see participating providers. POS plans differ from HMOs in that patients can receive coverage from physicians outside the network. However, patients pay more for care received from physicians outside the network and often must pay the full... 

All these results support our kinetic interpretations of these supersaturated gelling solutions. We assume that the network growth is described by the growth of individual domains, each one ruled by the autocatalytic model (S). This system behaves like an assembly of microdomains. Sach steroid in a supersaturation state is a potential germ of microdo.main. According to distribution curves of induction times for each microdomain, the typical kinetic curves for each part A and B of the phase diagram are obtained. 

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