@inbook{4307,
author = {Nicholas Barton},
booktitle = {Animal dispersal: small mammals as a model},
editor = {Stenseth, Nils C and Lidicker, William Z},
pages = {37 -- 60},
publisher = {Chapman Hall},
title = {{The genetic consequences of dispersal}},
year = {1992},
}
@article{4308,
author = {Nicholas Barton},
journal = {Evolution; International Journal of Organic Evolution},
number = {2},
pages = {551 -- 557},
publisher = {Wiley-Blackwell},
title = {{On the spread of new gene combinations in the third phase of Wright's shifting balance}},
volume = {46},
year = {1992},
}
@inproceedings{4504,
author = {Thomas Henzinger and Manna, Zohar and Pnueli,Amir},
pages = {545 -- 558},
publisher = {Springer},
title = {{What good are digital clocks?}},
doi = {10.1007/3-540-55719-9_103},
volume = {623},
year = {1992},
}
@inproceedings{4505,
abstract = {We describe finite-state programs over real-numbered time in a guarded-command language with real-valued clocks or, equivalently, as finite automata with real-valued clocks. Model checking answers the question which states of a real-time program satisfy a branching-time specification (given in an extension of CTL with clock variables). We develop an algorithm that computes this set of states symbolically as a fixpoint of a functional on state predicates, without constructing the state space.
For this purpose, we introduce a mu-calculus on computation trees over real-numbered time. Unfortunately, many standard program properties, such as response for all nonzeno execution sequences (during which time diverges), cannot be characterized by fixpoints: we show that the expressiveness of the timed mu-calculus is incomparable to the expressiveness of timed CTL. Fortunately, this result does not impair the symbolic verification of "implementable" real-time programs--those whose safety constraints are machine-closed with respect to diverging time and whose fairness constraints are restricted to finite upper bounds on clock values. All timed CTL properties of such programs are shown to be computable as finitely approximable fixpoints in a simple decidable theory.},
author = {Thomas Henzinger and Nicollin, Xavier and Sifakis, Joseph and Yovine, Sergio},
pages = {394 -- 406},
publisher = {IEEE},
title = {{Symbolic model checking for real-time systems}},
doi = {10.1109/LICS.1992.185551},
year = {1992},
}
@inbook{4507,
abstract = {We incorporate time into an interleaving model of concurrency. In timed transition systems, the qualitative fairness requirements of traditional transition system are replaced (and superseded) by quantitative lower-bound and upperbound timing constraints on transitions. The purpose of this paper is to explore the scope of applicability for the abstract model of timed transition systems. We demonstrate that the model can represent a wide variety of phenomena that routinely occur in conjunction with the timed execution of concurrent processes. Our treatment covers both processes that are executed in parallel on separate processors and communicate either through shared variables or by message passing, and processes that time-share a limited number of processors under a given scheduling policy. Often it is this scheduling policy that determines if a system meets its real-time requirements. Thus we explicitly address such questions as time-outs, interrupts, static and dynamic priorities.},
author = {Thomas Henzinger and Manna, Zohar and Pnueli,Amir},
booktitle = {Real Time: Theory in Practice},
pages = {226 -- 251},
publisher = {Springer},
title = {{Timed transition systems}},
doi = {10.1007/BFb0031995},
volume = {600},
year = {1992},
}
@article{4517,
abstract = {It has been observed repeatedly that the standard safety-liveness classification for properties of reactive systems does not fit for real-time properties. This is because the implicit “liveliness” of time shifts the spectrum towards the safety side. While, for example, response—that “something good” will happen eventually—is a classical liveness property, bounded response—that “something good” will happen soon, within a certain amount of time—has many characteristics of safety. We account for this phenomenon formally by defining safety and liveness relative to a given condition, such as the progress of time.},
author = {Thomas Henzinger},
journal = {Information Processing Letters},
number = {3},
pages = {135 -- 141},
publisher = {Elsevier},
title = {{Sooner Is Safer Than Later}},
doi = {10.1016/0020-0190(92)90005-G},
volume = {43},
year = {1992},
}
@inbook{4593,
abstract = {We survey logic-based and automata-based languages and techniques for the specification and verification of real-time systems. In particular, we discuss three syntactic extensions of temporal logic: time-bounded operators, freeze quantification, and time variables. We also discuss the extension of finite-state machines with clocks and the extension of transition systems with time bounds on the transitions. All of the resulting notations can be interpreted over a variety of different models of time and computation, including linear and branching time, interleaving and true concurrency, discrete and continuous time. For each choice of syntax and semantics, we summarize the results that are known about expressive power, algorithmic finite-state verification, and deductive verification.},
author = {Alur, Rajeev and Thomas Henzinger},
booktitle = {Real Time: Theory in Practice},
pages = {74 -- 106},
publisher = {Springer},
title = {{Logics and models of real time: A survey}},
doi = {10.1007/BFb0031984},
volume = {600},
year = {1992},
}
@inproceedings{4594,
abstract = {The authors introduce two-way timed automata-timed automata that can move back and forth while reading a timed word. Two-wayness in its unrestricted form leads, like nondeterminism, to the undecidability of language inclusion. However, if they restrict the number of times an input symbol may be revisited, then two-wayness is both harmless and desirable. The authors show that the resulting class of bounded two-way deterministic timed automata is closed under all boolean operations, has decidable (PSPACE-complete) emptiness and inclusion problems, and subsumes all decidable real-time logics we know. They obtain a strict hierarchy of real-time properties: deterministic timed automata can accept more languages as the bound on the number of times an input symbol may be revisited is increased. This hierarchy is also enforced by the number of alternations between past and future operators in temporal logic. The combination of the results leads to a decision procedure for a real-time logic with past operators
},
author = {Alur, Rajeev and Thomas Henzinger},
pages = {177 -- 186},
publisher = {IEEE},
title = {{Back to the future: Towards a theory of timed regular languages}},
doi = {10.1109/SFCS.1992.267774},
year = {1992},
}
@article{3469,
abstract = {Glutamate-operated ion channels (GluR channels) of the L-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-kainate subtype are found in both neurons and glial cells of the central nervous system. These channels are assembled from the GluR-A, -B, -C, and -D subunits; channels containing a GluR-B subunit show an outwardly rectifying current-voltage relation and low calcium permeability, whereas channels lacking the GluR-B subunit are characterized by a doubly rectifying current-voltage relation and high calcium permeability. Most cell types in the central nervous system coexpress several subunits, including GluR-B. However, Bergmann glia in rat cerebellum do not express GluR-B subunit genes. In a subset of cultured cerebellar glial cells, likely derived from Bergmann glial cells. GluR channels exhibit doubly rectifying current-voltage relations and high calcium permeability, whereas GluR channels of cerebellar neurons have low calcium permeability. Thus, differential expression of the GluR-B subunit gene in neurons and glia is one mechanism by which functional properties of native GluR channels are regulated.},
author = {Burnashev, Nail A and Khodorova, Alla and Peter Jonas and Helm, P. J. and Wisden, William and Monyer, Hannah and Seeburg, Peter H and Sakmann, Bert},
journal = {Science},
number = {5063},
pages = {1566 -- 1570},
publisher = {American Association for the Advancement of Science},
title = {{Calcium-permeable AMPA-kainate receptors in fusiform cerebellar glial cells.}},
doi = {10.1126/science.1317970},
volume = {256},
year = {1992},
}
@article{3470,
abstract = {Currents activated by glutamate receptor (GluR) agonists were recorded from outside-out patches isolated from the soma of visually identified pyramidal neurones of the (CA3 and CA1 region of rat hippocampal slices. α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). L-glutamate (L-Glu), and kainate (KA) were delivered either by bath application through perfusion of the recording chamber or by rapid application via a piezo-driven two-barrelled fast application system. 2. Bath application of each of the three agonists activated inward currents in all patches (n = 134) at holding potentials of -50 or -60 mV. The current amplitude increased in size between 3 to 30 μM-AMPA and 100 μM to 1 mM-KA. With this slow mode of bath application, the responses showed no apparent desensitization even at saturating concentrations of AMPA (30 μM) and KA (1 mM). 3. The ratio of currents activated by 30 μM-AMPA and 300 μM-KA showed a characteristic difference between CA3 and CA1 neurones. The ratio was 0.242 ± 0.028 (mean ± S.E.M., n = 16) for CA3 cell patches and 0.097 ± 0.012 (n = 8) for CA1 cell patches indicating that GluRs in the two cell populations are different. 4. The steady-state current-voltage relations (I-Vs) for AMPA- and KA-activated currents showed pronounced outward rectification for both cell types (when the main cations are Na+ in the bath and Cs+ in the pipette solution). The current reversed close to 0 mV and the ratio of chord conductances 80 mV on either side of the reversal potential was 2.66 for KA-activated currents in CA3 cell patches and 2.60 in CA1 cell patches. AMPA-activated currents showed a time-dependent increase after steps to positive membrane potentials and a decrease after steps to negative voltages, indicating that a gating process is responsible for outward rectification of the steady-state I-IV. 5. The permeability (P) of GluR channels was high for Na+ as compared to Cs+ for both cell types (P(Na)/P(Cs) = 0.88 and 0.84). The permeability was low for N-methyl-D-glucamine+ (P(NMG)/P(Cs) ≤ 0.03) and Ca2+ (P(Ca)/P(Cs) ≤0.05). 6. The current noise level increased during application of AMPA or KA. Apparent single-channel conductances obtained from fluctuation analysis were higher for AMPA than for KA, but similar for both cell types. In CA3 cell patches, AMPA activated channels with an apparent chord conductance of 7.2 pS, KA of 3.0 pS conductance. 7. Fast agonist application revealed desensitization of GluR channels which was dependent on the type of agonist, currents activated by AMPA and L-Glu rose rapidly to a peak and then desensitized to a steady-state current. In contrast, currents activated by fast application of KA rose to a plateau and did not desensitize. The steady state current expressed as a percentage of the peak current was higher for L-Glu than for AMPA and slightly higher for CA3 than for CA1 cell patches. For CA3 cell patches, this fraction amounted to 6.2 %, with 300 μM-L-Glu and 2.8%, with 300 μM-AMPA. For CA1 cell patches, corresponding values were 3.6 and 1.9 % 8. The dose response relations for the peak current activated by AMPA and L-Glu and the steady-state current activated by KA were similar for CA3 and CA1 cell patches. The order of potency was AMPA > L-Glu ≃ KA for both cell types EC50 values 189, 342 and 344 μM for CA3 cell patches and 183, 424 and 474 μM for CA1 cell patches). In all cases, the Hill coefficients ranged between 12 and 1.7. 8. The rise of AMPA and L-Glu-activated currents became faster with increasing agonist concentration for both cell types. With L-Glu, rise times decreased from about 3 ms at 100 μM to 500 μs at 3 mM. The delay for agonist concentrations ≥ 300 μM was described by the sum of two exponential functions. The time constant of the predominant fast component was slightly concentration dependent and decreased from about 12 ms at 300 μM to 8 ms at 3 mM-L-Glu. 10. The current voltage relations of the peak currents activated by 300 μM-AMPA were linear for both cell types with a reversal potential close to OmV. 11. It is concluded that the GluR channels in pyramidal cells of hippocampal CA3 and CA1 regions are distinet but share many pharmacological and functional properties. Comparison of the properties of native and recombinant GluRs suggests that in both CA3 and CA1 regions GluR channels are hetero-oligomers containing the GluR-B subunit.},
author = {Peter Jonas and Sakmann, Bert},
journal = {Journal of Physiology},
pages = {143 -- 171},
publisher = {Wiley-Blackwell},
title = {{Glutamate receptor channels in isolated patches from CA1 and CA3 pyramidal cells of rat hippocampal slices}},
volume = {455},
year = {1992},
}