A logic for reasoning about time and reliability

We present a logic for stating properties such as, "after a request for service there is at least a 98\045 probability that the service will be carried out within 2 seconds". The logic extends the temporal logic CTL by Emerson, Clarke and Sistla with time and probabilities. Formulas are interpreted over discrete time Markov chains. We give algorithms for checking that a given Markov chain satis- fies a formula in the logic. The algorithms require a polynomial number of arithmetic operations, in size of both the formula and\003This research report is a revised and extended version of a paper that has appeared under the title "A Framework for Reasoning about Time and Reliability" in the Proceeding of the 10thIEEE Real-time Systems Symposium, Santa Monica CA, December 1989. This work was partially supported by the Swedish Board for Technical Development (STU) as part of Esprit BRA Project SPEC, and by the Swedish Telecommunication Administration.1the Markov chain. A simple example is included to illustrate the algorithms

Selection for Seed Size and Coleoptile Length in Timothy (Phleum Pratense L.)

The intention of this study was to show the effect of selection for seed weight and coleoptile length on morphology and agronomically important characters in timothy (Phleum pratense L.). Two cycles of selection increased the seed weight as well as the length of coleoptile and root. The emergence from deep sowing in sand and in the field were insignificantly increased, whereas the percentage stand and the dry matter yield were decreased, albeit insignificantly. Inbreeding and linkage effects were considered possible causes for this

Generalizing Optical Geometry

We show that by employing the standard projected curvature as a measure of spatial curvature, we can make a certain generalization of optical geometry (Abramowicz and Lasota 1997, Class. Quantum Grav. 14 (1997) A23). This generalization applies to any spacetime that admits a hypersurface orthogonal shearfree congruence of worldlines. This is a somewhat larger class of spacetimes than the conformally static spacetimes assumed in standard optical geometry. In the generalized optical geometry, which in the generic case is time dependent, photons move with unit speed along spatial geodesics and the sideways force experienced by a particle following a spatially straight line is independent of the velocity. Also gyroscopes moving along spatial geodesics do not precess (relative to the forward direction). Gyroscopes that follow a curved spatial trajectory precess according to a very simple law of three-rotation. We also present an inertial force formalism in coordinate representation for this generalization. Furthermore, we show that by employing a new sense of spatial curvature (Jonsson, Class. Quantum Grav. 23 (2006) 1) closely connected to Fermat's principle, we can make a more extensive generalization of optical geometry that applies to arbitrary spacetimes. In general this optical geometry will be time dependent, but still geodesic photons move with unit speed and follow lines that are spatially straight in the new sense. Also, the sideways experienced (comoving) force on a test particle following a line that is straight in the new sense will be independent of the velocity.Comment: 19 pages, 1 figure. A more general analysis is presented than in the former version. See also the companion papers arXiv:0708.2493, arXiv:0708.2533 and arXiv:0708.253

SPECIFIC TRANSPLANTATION IMMUNITY IN RELATION TO ROUS SARCOMA VIRUS TUMORIGENESIS IN MICE

Tests for transplantation immunity and for the occurrence of virus-neutralizing serum antibodies were performed on mice, inoculated when newborn with the Schmidt-Ruppin strain of Rous sarcoma virus (RSV-SR). Mice developing no palpable primary sarcomas showed a clear-cut resistance against the isografting of established specifically antigenic Rous tumors. Transplantation tests performed on primary tumor hosts after extirpation of the tumors revealed neither any clear-cut immunity nor tolerance to the specific transplantation antigen(s). Serial pretreatment of operated primary tumor animals with irradiated autologous or syngeneic tumor cells resulted in a clear-cut transplantation immunity. Virus-neutralizing activity was only found in a few sera from newborn infected mice, and in these cases there was no positive correlation with the transplantation immunity. It seems probable that a successful immunization against the RSV-SR specific transplantation antigen(s) prevents the development of primary tumors. There is no indication of any tolerance to this antigen in connection with the induction of primary tumors

FURTHER STUDIES ON SPECIFIC TRANSPLANTATION ANTIGENS IN ROUS SARCOMA OF MICE

Mice allografted with different sarcomas, induced by the Schmidt-Ruppin variant of Rous sarcoma virus (RSV-SR), showed a resistance against subsequent isografting of 9 different Rous sarcomas. Transplantation resistance could also be induced by Rous mouse tumor cells x-irradiated with 8000 r or with cell-free tumor extracts, containing no demonstrable virus. No transplantation resistance could be demonstrated after allograft pretreatment with various polyoma tumors or non-viral tumors. Allograft pretreatment with Rous tumors induced no demonstrable resistance against isografting of polyoma tumors. Inoculation of RSV-SR or Rous chicken sarcoma suspension into adult mice gave no clear cut resistance against isografting of mouse sarcomas. Neither after allografting of Rous tumors nor after virus or chicken sarcoma inoculation into adult mice could virus-neutralizing activity be demonstrated in the sera. The results demonstrate the presence of common, specific transplantation antigen(s) in different Rous sarcomas in mice and speak against an identity between the transplantation antigen(s) and viral antigen(s)

Betydelsebeskrivningens förutsätningar i en enspråkig ordbok

Monolingual dictionaries are by their very nature truly defining, unlike bilingual ( ormultilingual) dictionaries, translation dictionaries. This article is mainly about thesemantic basis of definition.Having distinguished in the lexicon of a natura! language lexical elements representing"languages within the language", that is, words which are provincial, sociallyand stylistically marked, as well as purely technical terminology, the author discussesthe more uniform system of a standard language. The key concept is lexeme. Alexeme can correspond to a word in the traditional sense but can also correspond to adistinct use of a word. lgnoring the phenomenon of synonymy, a lexeme contrastswith every other lexeme. There are also elements of opposition in a more specialsense. There are relatively often opposing pairs such as (in Swedish) fattig : rik; stor :liten; pojke : flicka; lärare : elev, besides which there are also fix.ed oppositions consistingof several elements, such as bäck : å : älv or sommar : höst : vinter : vår. Adistinct hierarchical order on a small scale, in the form of "mini semantic fields" (suchas the hyperonym vattendrag with its hyponyms bäck, å, älv) occurs in the lexicon.On the other hand, there does not appear to be any general hierarchical order for !argelexeme spheres, much less for the entire lexicon. In fäet, there is probably no overalllexical structure which would be a full equivalent to grarnmatical and phonologicalstructure.To put it in very general terms, the task of the lexicographer is to do justice to thelinguistic division of the conceptual world by means of lexemes and to the elements ofstructure in the strict sense which the lexicon undoubtedly displays

De stora historiska ordböckernas särart

Svenska Akademiens ordbok (SAOB) tilhör gruppen de stora historiska ordböckerna och har sina närmaste likar i New English Dictionary, Grimm, Deutsches Wörterbuch och Woordenboek der Nederlandsche Taal. Denna typ av ordböcker behandlar mycket utförligt inom samma pärmar samtidsspråket och språket bakåt i tiden ned til gränsen mot ett avgränsbart äldre språkskede, i SAOB:s fall fornsvenskan. Denna sambeskrivning av en så lång språkperiods ordförråd ger SAOB och dess likar en klar särart, när man järnför dem med å ena sidan (hand)ordböcker för nuspråket, å andra sidan ordböcker för en avgränsad äldre språkperiod. Klarast framträder nog särarten i de fall där nutida och äldre betydelsestruktur "krockar" hos ett ord