@article{4072, abstract = {We show that the total number of edges ofm faces of an arrangement ofn lines in the plane isO(m 2/3– n 2/3+2 +n) for any>0. The proof takes an algorithmic approach, that is, we describe an algorithm for the calculation of thesem faces and derive the upper bound from the analysis of the algorithm. The algorithm uses randomization and its expected time complexity isO(m 2/3– n 2/3+2 logn+n logn logm). If instead of lines we have an arrangement ofn line segments, then the maximum number of edges ofm faces isO(m 2/3– n 2/3+2 +n (n) logm) for any>0, where(n) is the functional inverse of Ackermann's function. We give a (randomized) algorithm that produces these faces and takes expected timeO(m 2/3– n 2/3+2 log+n(n) log2 n logm).}, author = {Edelsbrunner, Herbert and Guibas, Leonidas and Sharir, Micha}, issn = {1432-0444}, journal = {Discrete & Computational Geometry}, number = {1}, pages = {161 -- 196}, publisher = {Springer}, title = {{The complexity and construction of many faces in arrangements of lines and of segments}}, doi = {10.1007/BF02187784}, volume = {5}, year = {1990}, } @inproceedings{4073, abstract = {A number of rendering algorithms in computer graphics sort three-dimensional objects by depth and assume that there is no cycle that makes the sorting impossible. One way to resolve the problem caused by cycles is to cut the objects into smaller pieces. The problem of estimating how many such cuts are always sufficient is addressed. A few related algorithmic and combinatorial geometry problems are considered.}, author = {Chazelle, Bernard and Edelsbrunner, Herbert and Guibas, Leonidas and Pollack, Richard and Seidel, Raimund and Sharir, Micha and Snoeyink, Jack}, booktitle = {31st Annual Symposium on Foundations of Computer Science}, isbn = {0-8186-2082-X}, location = {St. Louis, MO, United States of America}, pages = {242 -- 251}, publisher = {IEEE}, title = {{Counting and cutting cycles of lines and rods in space}}, doi = {10.1109/FSCS.1990.89543}, year = {1990}, } @article{4074, abstract = {We present upper and lower bounds for extremal problems defined for arrangements of lines, circles, spheres, and alike. For example, we prove that the maximum number of edges boundingm cells in an arrangement ofn lines is Θ(m 2/3 n 2/3 +n), and that it isO(m 2/3 n 2/3 β(n) +n) forn unit-circles, whereβ(n) (and laterβ(m, n)) is a function that depends on the inverse of Ackermann's function and grows extremely slowly. If we replace unit-circles by circles of arbitrary radii the upper bound goes up toO(m 3/5 n 4/5 β(n) +n). The same bounds (without theβ(n)-terms) hold for the maximum sum of degrees ofm vertices. In the case of vertex degrees in arrangements of lines and of unit-circles our bounds match previous results, but our proofs are considerably simpler than the previous ones. The maximum sum of degrees ofm vertices in an arrangement ofn spheres in three dimensions isO(m 4/7 n 9/7 β(m, n) +n 2), in general, andO(m 3/4 n 3/4 β(m, n) +n) if no three spheres intersect in a common circle. The latter bound implies that the maximum number of unit-distances amongm points in three dimensions isO(m 3/2 β(m)) which improves the best previous upper bound on this problem. Applications of our results to other distance problems are also given.}, author = {Clarkson, Kenneth and Edelsbrunner, Herbert and Guibas, Leonidas and Sharir, Micha and Welzl, Emo}, issn = {1432-0444}, journal = {Discrete & Computational Geometry}, number = {1}, pages = {99 -- 160}, publisher = {Springer}, title = {{Combinatorial complexity bounds for arrangements of curves and spheres}}, doi = {10.1007/BF02187783}, volume = {5}, year = {1990}, } @article{4075, abstract = {A key problem in computational geometry is the identification of subsets of a point set having particular properties. We study this problem for the properties of convexity and emptiness. We show that finding empty triangles is related to the problem of determining pairs of vertices that see each other in a star-shaped polygon. A linear-time algorithm for this problem which is of independent interest yields an optimal algorithm for finding all empty triangles. This result is then extended to an algorithm for finding empty convex r-gons (r> 3) and for determining a largest empty convex subset. Finally, extensions to higher dimensions are mentioned.}, author = {Dobkin, David and Edelsbrunner, Herbert and Overmars, Mark}, issn = {1432-0541}, journal = {Algorithmica}, number = {4}, pages = {561 -- 571}, publisher = {Springer}, title = {{Searching for empty convex polygons}}, doi = {10.1007/BF01840404}, volume = {5}, year = {1990}, } @inproceedings{4076, abstract = {We present an algorithm to compute a Euclidean minimum spanning tree of a given set S of n points in Ed in time O(Td(N, N) logd N), where Td(n, m) is the time required to compute a bichromatic closest pair among n red and m blue points in Ed. If Td(N, N) = Ω(N1+ε), for some fixed ε > 0, then the running time improves to O(Td(N, N)). Furthermore, we describe a randomized algorithm to compute a bichromatic closets pair in expected time O((nm log n log m)2/3+m log2 n + n log2 m) in E3, which yields an O(N4/3log4/3 N) expected time algorithm for computing a Euclidean minimum spanning tree of N points in E3.}, author = {Agarwal, Pankaj and Edelsbrunner, Herbert and Schwarzkopf, Otfried and Welzl, Emo}, booktitle = {Proceedings of the 6th annual symposium on Computational geometry}, isbn = {978-0-89791-362-1}, location = {Berkeley, CA, United States}, pages = {203 -- 210}, publisher = {ACM}, title = {{ Euclidean minimum spanning trees and bichromatic closest pairs}}, doi = {10.1145/98524.98567}, year = {1990}, } @inproceedings{4077, abstract = {We prove that for any set S of n points in the plane and n3-α triangles spanned by the points of S there exists a point (not necessarily of S) contained in at least n3-3α/(512 log25 n) of the triangles. This implies that any set of n points in three - dimensional space defines at most 6.4n8/3 log5/3 n halving planes.}, author = {Aronov, Boris and Chazelle, Bernard and Edelsbrunner, Herbert and Guibas, Leonidas and Sharir, Micha and Wenger, Rephael}, booktitle = {Proceedings of the 6th annual symposium on Computational geometry}, isbn = {978-0-89791-362-1}, location = {Berkley, CA, United States}, pages = {112 -- 115}, publisher = {ACM}, title = {{Points and triangles in the plane and halving planes in space}}, doi = {10.1145/98524.98548}, year = {1990}, } @inproceedings{4078, abstract = {In this paper we derived combinatorial point selection results for geometric objects defined by pairs of points. In a nutshell, the results say that if many pairs of a set of n points in some fixed dimension each define a geometric object of some type, then there is a point covered by many of these objects. Based on such a result for three-dimensional spheres we show that the combinatorial size of the Delaunay triangulation of a point set in space can be reduced by adding new points. We believe that from a practical point of view this is the most important result of this paper.}, author = {Chazelle, Bernard and Edelsbrunner, Herbert and Guibas, Leonidas and Hershberger, John and Seidel, Raimund and Sharir, Micha}, booktitle = {Proceedings of the 6th annual symposium on computational geometry}, isbn = {978-0-89791-362-1}, location = {Berkley, CA, United States}, pages = {116 -- 127}, publisher = {ACM}, title = {{Slimming down by adding; selecting heavily covered points}}, doi = {10.1145/98524.98551}, year = {1990}, } @article{4310, author = {Barton, Nicholas H and Jones, Steve}, issn = {1476-4687}, journal = {Nature}, pages = {415 -- 416}, publisher = {Nature Publishing Group}, title = {{The language of the genes}}, doi = {10.1038/346415a0}, volume = {346}, year = {1990}, } @inbook{4311, author = {Barton, Nicholas H and Clark, A.}, booktitle = {Population biology: Ecological and evolutionary viewpoints}, editor = {Wöhrmann, Klaus and Jain, Subodh}, isbn = { 978-3642744761}, pages = {115 -- 174}, publisher = {Springer}, title = {{Population structure and processes in evolution}}, doi = {10.1007/978-3-642-74474-7_5}, year = {1990}, } @inproceedings{4510, abstract = {The interleaving model is both adequate and sufficiently abstract to allow for the practical specification and verification of many properties of concurrent systems. We incorporate real time into this model by defining the abstract notion of a real-time transition system as a conservative extension of traditional transition systems: qualitative fairness requirements are replaced (and superseded) by quantitative lower-bound and upper-bound real-time requirements for transitions. We present proof rules to establish lower and upper real-time bounds for response properties of real-time transition systems. This proof system can be used to verify bounded-invariance and bounded-response properties, such as timely termination of shared-variables multi-process systems, whose semantics is defined in terms of real-time transition systems.}, author = {Henzinger, Thomas A and Manna, Zohar and Pnueli, Amir}, booktitle = { Proceedings of the 5th Jerusalem Conference on Information Technology}, isbn = {0-8186-2078-1}, location = {Jerusalem, Israel}, pages = {717 -- 730}, publisher = {IEEE}, title = {{An interleaving model for real time}}, doi = {10.1109/JCIT.1990.128356}, year = {1990}, } @inproceedings{4522, abstract = {We introduce a novel extension of propositional modal logic that is interpreted over Kripke structures in which a value is associated with every possible world. These values are. however, not treated as full first-order objects: they can be accessed only by a very restricted form of quantification: the "freeze" quantifier binds a variable to the value of the current world. We present a complete proof system for this ("half-order") modal logic. As a special case, we obtain the real-time temporal logic TPTL of [AH891: the models are restricted to infinite sequences of states, whose values are monotonically increasing natural numbers. The ordering relation between states is interpreted as temporal precedence. while the value associated with a state is interpreted as its "rear time. We extend our proof system to be complete for TPTL. and demonstrate how it can be used to derive real-time properties. }, author = {Henzinger, Thomas A}, booktitle = {Proceedings of the 9th annual ACM symposium on Principles of distributed computing}, isbn = {978-0-89791-404-8}, location = {Quebec City, Canada}, pages = {281 -- 296}, publisher = {ACM}, title = {{Half-order modal logic: How to prove real-time properties}}, doi = {10.1145/93385.93429}, year = {1990}, } @inproceedings{4597, abstract = {A unifying framework for the study of real-time logics is developed. In analogy to the untimed case, the underlying classical theory of timed state sequences is identified, it is shown to be nonelementarily decidable, and its complexity and expressiveness are used as a point of reference. Two orthogonal extensions of PTL (timed propositional temporal logic and metric temporal logic) that inherit its appeal are defined: they capture elementary, yet expressively complete, fragments of the theory of timed state sequences, and thus are excellent candidates for practical real-time specification languages}, author = {Alur, Rajeev and Henzinger, Thomas A}, booktitle = { 5th Annual IEEE Symposium on Logic in Computer Science}, isbn = {0-8186-2073-0}, location = {Philadelphia, PA, USA}, pages = {390 -- 401}, publisher = {IEEE}, title = {{Real-time logics: Complexity and expressiveness}}, doi = {10.1109/LICS.1990.113764}, year = {1990}, } @article{2480, abstract = {Functional cDNA clones for rat neuromedin K receptor were isolated from a rat brain cDNA library by cross-hybridization with the bovine substance K recepor cDNA. Injection of the mRNA synthesized in vitro from the cloned cDNA into Xenopus oocytes elicited electrophysiological responses to tachykinins, with the most potent sensitivity being to neuromedin K. Ligand-binding displacement in membranes of mammalian COS cells transfected with the cDNA indicated the rank order of affinity of the receptor to tachykinins; neuromedin K > substance K > substance P. The hybridization analysis showed that the neuromedin K receptor mRNA is expressed in both the brain and the peripheral tissues at different levels. The rat neuromedin K receptor consists of 452 amino acid residues and belongs to the family of G protein-coupled receptors, which are thought to have seven transmembrane domains. The sequence comparison of the rat neuromedin K, substance P, and substance K receptors revealed that these receptors are highly conserved in the seven transmembrane domains and the cytoplasmic sides of the receptors. They also show some structural characteristics, including the common presence of histidine residues in transmembrane segments V and VI and the difference in the numbers and distributions of serine and threonine residues as possible phosphorylation sites in the cytoplasmic regions. This paper thus presents the first comprehensive analysis of the molecular nature of the multiple peptide receptors that exhibit similar but pharmacologically distinguishable activities.}, author = {Shigemoto, Ryuichi and Yokota, Yoshifumi and Tsuchida, Kunihiro and Nakanishi, Shigetada}, issn = {1083-351X}, journal = {Journal of Biological Chemistry}, number = {2}, pages = {623 -- 628}, publisher = {American Society for Biochemistry and Molecular Biology}, title = {{Cloning and expression of a rat neuromedin K receptor cDNA}}, doi = {10.1016/s0021-9258(19)40095-1 }, volume = {265}, year = {1990}, } @article{2481, abstract = {The family of mammalian tachykinin receptors consists of substance P receptor (SPR), neuromedin K receptor (NKR) and substance K receptor (SKR). In this investigation, tissue and regional distributions of the mRNAs for the three rat tachykinin receptors were investigated by blot-hybridization and RNase-protection analyses using the previously cloned receptor cDNAs. SPR mRNA is widely distributed in both the nervous system and peripheral tissues and is expressed abundantly in the hypothalamus and olfactory buld, as well as in the urinary bladder, salivary glands and small and large intestines. In contrast, NKR mRNA is predominantly expressed in the nervous system, particularly in the cortex, hypothalamus and cerebellum, whereas SKR mRNA expression is restricted to the peripheral tissues, being abundant in the urinary bladder, large intestine, stomach and adenal glands. Thus, the mRNAs for the three tachykinin receptors show distinct patterns of expression between the nervous system and peripheral tissues. Blot-hybridization analysis in combination with S1 nuclease protection and primer-extension analyses revealed that there are two large forms of SKR mRNA expressed commonly in the peripheral tissues, and two additional small forms of the mRNA expressed specifically in the adrenal gland and eye. These analyses also showed that the multiple forms of SKR mRNA differ in the lengths of the 5' mRNA portions, and that the two small forms of the mRNA, if translated, encode a truncated SKR polypeptide lacking the first two transmembrane domains. This investigation thus provides the comprehensive analysis of the distribution and mode of expression of the mRNAs for the multiple peptide receptors and offers a new basis on which to interpret the diverse functions of multiple tachykinin peptides in the CNS and peripheral tissues.}, author = {Tsuchida, Kunihiro and Shigemoto, Ryuichi and Yokota, Yoshifumi and Nakanishi, Shigetada}, issn = {1432-1033}, journal = {European Journal of Biochemistry}, number = {3}, pages = {751 -- 757}, publisher = {Wiley-Blackwell}, title = {{Tissue distribution and quantitation of the mRNAs for three rat tachykinin receptors}}, doi = {10.1111/j.1432-1033.1990.tb19396.x}, volume = {193}, year = {1990}, } @article{2528, abstract = {We previously reported a novel rat membrane protein that exhibits a voltage-dependent potassium channel activity on the basis of molecular cloning combined with an electrophysiological assay. This protein, termed I(sK) protein, is small and different from the conventional potassium channel proteins but induces selective permeation of potassium ions on its expression in Xenopus oocytes. In this investigation, we examined cellular localization of rat I(sK) protein by preparing three different types of antibody that specifically reacts with a distinct part of rat I(sK) protein. Immunohistochemical analysis using these antibody preparations demonstrated that rat I(sK) protein is confined to the apical membrane portion of epithelial cells in the proximal tubule of the kidney, the submandibular duct and the uterine endometrium. The observed tissue distribution of rat I(sK) protein was consistent with that of the I(sK) protein mRNA determined by blot hybridization analysis. In epithelial cells, the sodium, potassium-ATPase pump in the basolateral membrane generates a sodium gradient across the epithelial cell and allows sodium ions to enter the cell through the apical membrane. Thus, taking into account the cellular localization of the I(sK) protein, together with its electrophysiological properties, we discussed a possible function of the I(sK) protein, namely that this protein is involved in potassium permeation in the apical membrane of epithelial cells through the depolarizing effect of sodium entry.}, author = {Sugimoto, Tetsuo and Tanabe, Yasuto and Shigemoto, Ryuichi and Iwai, Masazumi and Takumi, Toru and Ohkubo, Hiroaki and Nakanishi, Shigetada}, issn = {1432-1424}, journal = {Journal of Membrane Biology}, number = {1}, pages = {39 -- 47}, publisher = {Springer}, title = {{Immunohistochemical study of a rat membrane protein which induces a selective potassium permeation: Its localization in the apical membrane portion of epithelial cells}}, doi = {10.1007/BF01869604}, volume = {113}, year = {1990}, } @article{2721, abstract = {We consider a multidimensional system consisting of a particle of mass M and radius r (molecule), surrounded by an infinite ideal gas of point particles of mass m (atoms). The molecule is confined to the unit ball and interacts with its boundary (barrier) via elastic collision, while the atoms are not affected by the boundary. We obtain convergence to equilibrium for the molecule from almost every initial distribution on its position and velocity. Furthermore, we prove that the infinite composite system of the molecule and the atoms is Bernoulli.}, author = {Erdös, László and Tuyen, Dao}, issn = {1572-9613}, journal = {Journal of Statistical Physics}, number = {5-6}, pages = {1589 -- 1602}, publisher = {Springer}, title = {{Ergodic properties of the multidimensional rayleigh gas with a semipermeable barrier}}, doi = {10.1007/BF01334766}, volume = {59}, year = {1990}, } @article{3465, abstract = {Asymmetrical displacement currents and Na currents of single myelinated nerve fibers of Xenopus laevis were studied in the temperature range from 5 to 24 degrees C. The time constant of the on-response at E = 4 mV, tau on, was strongly temperature dependent, whereas the amount of displaced charge at E = 39 mV, Qon, was only slightly temperature dependent. The mean Q10 for tau on-1 was 2.54, the mean Q10 for Qon was 1.07. The time constant of charge immobilization, tau i, at E = 4 mV varied significantly (alpha = 0.001) with temperature. The mean Q10 for tau i-1 was 2.71 +/- 0.38. The time constants of immobilization of gating charge and of fast inactivation of Na permeability were similar in the temperature range from 6 to 22 degrees C. The Qoff/Qon ratio for E = 4 mV pulses of 0.5 msec duration decreased with increasing temperature. The temperature dependence of the time constant of the off-response could not be described by a single Q10 value, since the Q10 depended on the duration of the test pulse. Increasing temperature shifted Qon (E) curves to more negative potentials by 0.51 mV K-1, but shifted PNa (E) curves and h infinity (E) curves to more positive potentials by 0.43 and 0.57 mV K-1, respectively. h infinity (E = -70 mV) increased monotonously with increasing temperature. The present data indicate that considerable entropy changes may occur when the Na channel molecule passes from closed through open to inactivated states.}, author = {Jonas, Peter M}, issn = {1432-1424}, journal = {Journal of Membrane Biology}, number = {3}, pages = {277 -- 289}, publisher = {Springer}, title = {{Temperature dependence of gating current in myelinated nerve fibers}}, doi = {10.1007/BF01870958}, volume = {112}, year = {1989}, } @article{3466, abstract = {Amphibian myelinated nerve fibers were treated with collagenase and protease. Axons with retraction of the myelin sheath were patch-clamped in the nodal and paranodal region. One type of Na channel was found. It has a single-channel conductance of 11 pS (15 degrees C) and is blocked by tetrodotoxin. Averaged events show the typical activation and inactivation kinetics of macroscopic Na current. Three potential-dependent K channels were identified (I, F, and S channel). The I channel, being the most frequent type, has a single-channel conductance of 23 pS (inward current, 105 mM K on both sides of the membrane), activates between -60 and -30 mV, deactivates with intermediate kinetics, and is sensitive to dendrotoxin. The F channel has a conductance of 30 pS, activates between -40 and 60 mV, and deactivates with fast kinetics. The former inactivates within tens of seconds; the latter inactivates within seconds. The third type, the S channel, has a conductance of 7 pS and deactivates slowly. All three channels can be blocked by external tetraethylammonium chloride. We suggest that these distinct K channel types form the basis for the different components of macroscopic K current described previously.}, author = {Jonas, Peter M and Bräu, Michael and Hermsteiner, Markus and Vogel, Werner}, issn = {1091-6490}, journal = {PNAS}, number = {18}, pages = {7238 -- 7242}, publisher = {National Academy of Sciences}, title = {{Single-channel recording in myelinated nerve fibers reveals one type of Na channel but different K channels}}, doi = {10.1073/pnas.86.18.7238}, volume = {86}, year = {1989}, } @inproceedings{3549, abstract = {We study three types of spatial triangulations: Delaunay triangulations, triangulations with non-obtuse dihedral angles, and KJ-triangulations. The latter satisfy a certain angle condition useful for finite element approximation. We show that the condition for Delaunay triangulations is incomparable with the other two conditions, and that triangulations with non-obtuse dihedral angles are necessarily also KJ-triangulations. These relationships are in sharp contrast to the ones in the planar case. }, author = {Edelsbrunner, Herbert}, pages = {83 -- 89}, publisher = {Institute of the Electronics, Information and Communication Enginneers}, title = {{Spatial triangulations with dihedral angle conditions}}, year = {1989}, } @article{3652, abstract = {Frequency-dependent selection against rare forms can maintain clines. For weak selection, s, in simple linear models of frequency-dependence, single locus clines are stabilized with a maximum slope of between square root of s/square root of 8 sigma and square root of s/square root of 12 delta, where sigma is the dispersal distance. These clines are similar to those maintained by heterozygote disadvantage. Using computer simulations, the weak-selection analytical results are extended to higher selection pressures with up to three unlinked genes. Graphs are used to display the effect of selection, migration, dominance, and number of loci on cline widths, speeds of cline movements, two-way gametic correlations ("linkage disequilibria"), and heterozygote deficits. The effects of changing the order of reproduction, migration, and selection, are also briefly explored. Epistasis can also maintain tension zones. We show that epistatic selection is similar in its effects to frequency-dependent selection, except that the disequilibria produced in the zone will be higher for a given level of selection. If selection consists of a mixture of frequency-dependence and epistasis, as is likely in nature, the error made in estimating selection is usually less than twofold. From the graphs, selection and migration can be estimated using knowledge of the dominance and number of genes, of gene frequencies and of gametic correlations from a hybrid zone.}, author = {Mallet, James and Barton, Nicholas H}, issn = {0016-6731}, journal = {Genetics}, number = {4}, pages = {967 -- 976}, publisher = {Genetics Society of America}, title = {{Inference from clines stabilized by frequency-dependent selection}}, doi = {10.1093/genetics/122.4.967}, volume = {122}, year = {1989}, }