@inproceedings{11802, abstract = {In this paper we survey algorithmic aspects of Web information retrieval. As an example, we discuss ranking of search engine results using connectivity analysis.}, author = {Henzinger, Monika H}, booktitle = {8th Annual European Symposium on Algorithms}, isbn = {9783540410041}, issn = {1611-3349}, location = {Saarbrücken, Germany}, pages = {1–8}, publisher = {Springer Nature}, title = {{Web information retrieval - an algorithmic perspective}}, doi = {10.1007/3-540-45253-2_1}, volume = {1879}, year = {2000}, } @article{11893, abstract = {We present fully dynamic algorithms for maintaining the biconnected components in general and plane graphs. A fully dynamic algorithm maintains a graph during a sequence of insertions and deletions of edges or isolated vertices. Let m be the number of edges and n be the number of vertices in a graph. The time per operation of the best deterministic algorithms is 𝑂(𝑛√) in general graphs and O(log n) in plane graphs for fully dynamic connectivity and O(min m2/3 ,n}) in general graphs and 𝑂(𝑛√) in plane graphs for fully dynamic biconnectivity. We improve the later running times to 𝑂(𝑚log𝑛‾‾‾‾‾‾‾√) in general graphs and O(log 2n ) in plane graphs. Our algorithm for general graphscan also find the biconnected components of all vertices in time O(n).}, author = {Henzinger, Monika H}, issn = {1095-7111}, journal = {SIAM Journal on Computing}, number = {6}, pages = {1761--1815}, publisher = {Society for Industrial & Applied Mathematics}, title = {{Improved data structures for fully dynamic biconnectivity}}, doi = {10.1137/s0097539794263907}, volume = {29}, year = {2000}, } @inproceedings{2325, author = {Robert Seiringer}, pages = {53 -- 72}, publisher = {American Mathematical Society}, title = {{Inequalities for Schrödinger operators and applications to the stability of matter problem }}, doi = {10.1090/conm/529}, volume = {529}, year = {2000}, } @inproceedings{2342, abstract = {In the theoretical description of recent experiments with dilute Bose gases confined in external potentials the Gross-Pitaevskii equation plays an important role. Its status as an approximation for the quantum mechanical many-body ground state problem has recently been rigorously clarified. A summary of this work is presented here.}, author = {Seiringer, Robert and Lieb, Élliott and Yngvason, Jakob}, booktitle = {Proceedings of the International Symposium on Quantum Theory and Symmetries}, isbn = {9789810242374 }, pages = {101 -- 110}, publisher = {World Scientific Publishing}, title = {{The ground state energy and density of interacting bosons in a trap}}, year = {2000}, } @article{2343, abstract = {We study the energy levels of a single particle in a homogeneous magnetic field and in an axially symmetric external potential. For potentials that are superharmonic off the central axis, we find a general 'pseudoconcave' ordering of the ground state energies of the Hamiltonian restricted to the sectors with fixed angular momentum. The physical applications include atoms and ions in strong magnetic fields. There the energies are monotone increasing and concave in angular momentum. In the case of a periodic chain of atoms, the pseudoconcavity extends to the entire lowest band of Bloch functions.}, author = {Baumgartner, Bernhard and Robert Seiringer}, journal = {Letters in Mathematical Physics}, number = {3}, pages = {213 -- 226}, publisher = {Springer}, title = {{On the ordering of energy levels in homogeneous magnetic fields}}, doi = { 10.1023/A:1010978807635}, volume = {54}, year = {2000}, } @article{2344, abstract = {The ground-state properties of interacting Bose gases in external potentials, as considered in recent experiments, are usually described by means of the Gross-Pitaevskii energy functional. We present here a rigorous proof of the asymptotic exactness of this approximation for the ground-state energy and particle density of a dilute Bose gas with a positive interaction.}, author = {Lieb, Élliott and Seiringer, Robert and Yngvason, Jakob}, issn = {0556-2791}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, number = {4}, pages = {436021 -- 4360213}, publisher = {American Physical Society}, title = {{Bosons in a trap: A rigorous derivation of the Gross-Pitaevskii energy functional}}, doi = {10.1103/PhysRevA.61.043602}, volume = {61}, year = {2000}, } @inproceedings{2418, abstract = {For an absolutely continuous probability measure μ on Rd and a nonnegative integer k, let sk(μ, 0) denote the probability that the convex hull of k+d+1 random points which are i.i.d. according to μ contains the origin 0. For d and k given, we determine a tight upper bound on sk(μ, 0), and we characterize the measures in Rd which attain this bound. This result can be considered a continuous analogue of the Upper Bound Theorem for the maximal number of faces of convex polytopes with a given number of vertices. For our proof we introduce so-called h-functions, continuous counterparts of h-vectors for simplicial convex polytopes.}, author = {Wagner, Uli and Welzl, Emo}, booktitle = {Proceedings of the 16th annual symposium on Computational geometry}, isbn = {9781581132243}, location = {Clear Water Bay Kowloon, Hong Kong}, pages = {50 -- 56}, publisher = {ACM}, title = {{Origin-embracing distributions or a continuous analogue of the Upper Bound Theorem}}, doi = {10.1145/336154.336176}, year = {2000}, } @inbook{2494, abstract = {This chapter focuses on metabotropic glutamate receptors (mGluRs). These receptors are linked to several intracellular signal transduction mechanisms via G-protein and are implicated in diverse functions of the mammalian central nervous system (CNS). These functions include mediation of slow excitatory and inhibitory responses; regulation of calcium channels, potassium channels, and non-selective cation channels; inhibition and facilitation of transmitter release; induction of long-term potentiation and long-term depression; and regulation of neuronal development. Functional diversity of the metabotropic glutamate receptor is reflected in molecular diversity of receptor subtypes. The sites of action of mGluRs are widely found throughout different membrane compartments of neuronal and glial cells. The chapter reviews the differential subcellular localization of metabotropic glutamate receptors in relation to transmitter release sites. Patterns of subcellular localization of mGluRs are different among three subgroups: group I and III mGluRs are mainly localized to somatodendritic and axonal domains of neurons, respectively, while group II mGluRs are extensively localized to both domains as well as to glial cell processes.}, author = {Shigemoto, Ryuichi and Mizuno, Noboru}, booktitle = {Glutamate}, issn = {0924-8196}, pages = {63 -- 98}, publisher = {Elsevier}, title = {{Chapter III Metabotropic glutamate receptors - immunocytochemical and in situ hybridization analyses}}, doi = {10.1016/S0924-8196(00)80044-5}, volume = {18}, year = {2000}, } @article{2598, abstract = {There are many types of cerebellar ataxia, including ataxia due to congenital or metabolic disorders and a paraneoplastic form in patients with gynecologic cancer, breast cancer, lung cancer, or Hodgkin's disease.1 This paraneoplastic syndrome is the only type of cerebellar ataxia associated with autoantibodies against neuronal antigens. Often, the neuronal antigens are aberrantly expressed by the tumor cells.2-4 The antineuronal autoantibodies are believed to cause cerebellar ataxia, but this is unproved.5,6 In Hodgkin's disease, the lymphoma precedes the ataxia by months to years in 80 percent of patients, and ataxia often occurs during a prolonged complete remission.4 Among patients with this type of ataxia, 30 percent have anti–Purkinje-cell antibodies, some of which have the features of the neuronal antibody anti-Tr.4,7 We identified a new autoantibody in two patients with severe cerebellar ataxia that developed while they were in remission from Hodgkin's disease. The antibody reacts specifically with the metabotropic glutamate receptor mGluR1 in mouse brain. Metabotropic glutamate receptors belong to a large family of cell-surface receptors that transmit signals into the cell by coupling to guanine nucleotide-binding proteins (G proteins) in the cytoplasm. Purified IgG from the serum of both patients blocked the glutamate-stimulated formation of inositol phosphates in Chinese-hamster-ovary (CHO) cells that expressed mGluR1α, and the injection of IgG from serum or cerebrospinal fluid into the cerebellar subarachnoid space of mice caused severe, reversible ataxia. These results indicate that antineuronal autoantibodies can cause disease of the central nervous system by blocking neuronal receptors.}, author = {Sillevis Smitt, Peter and Kinoshita, Ayae and De Leeuw, Bertie and Moll, Wiebe and Coesmans, Michiel and Jaarsma, Dick and Henzen Logmans, Sonja and Vecht, Charles and De Zeeuw, Chris and Sekiyama, Naotaka and Nakanishi, Shigetada and Shigemoto, Ryuichi}, issn = {0028-4793}, journal = {New England Journal of Medicine}, number = {1}, pages = {21 -- 27}, publisher = {Massachussetts Medical Society}, title = {{Paraneoplastic cerebellar ataxia due to autoantibodies against a glutamate receptor}}, doi = {10.1056/NEJM200001063420104}, volume = {342}, year = {2000}, } @article{2599, abstract = {The synaptic relationship between substance P (SP) and its receptor, i.e., neurokinin-1 receptor (NK1R), was examined in the striatum of the rat by confocal laser-scanning microscopy and electron microscopy. For confocal laser-scanning microscopy, triple-immunofluorescence histochemistry was performed to label NK1R, SP, and vesicular acetylcholine transporter (a specific marker for cholinergic neurons). In electron microscopic double- immunolabeling study, immunoreactivity for NK1R was detected with the silver- intensified gold method, while immunoreactivity for SP was detected with peroxidase immunohistochemistry. Simultaneous immunolabeling of NK1R and SP revealed significant mismatch at the synaptic level: although some SP- immunopositive axon terminals were in synaptic contact with NK1R- immunopositive sites of plasma membrane, NK1R-immunoreactivity was observed at both synaptic and non-synaptic sites of plasma membrane. Thus, SP released from the sites remote from NK1Rs might diffuse in the extracellular fluid to act, as a paracrine neurotransmitter, on NK1Rs distant from its releasing site. SP neurotransmission in the striatum might occur not only synaptically but also extrasynaptically. The SP-NK1R system might constitute an association system within the striatum.}, author = {Li, Jin and Wang, Dan and Kaneko, Takeshi and Shigemoto, Ryuichi and Nomura, Sakashi and Mizuno, Noboru}, issn = {0021-9967}, journal = {Journal of Comparative Neurology}, number = {2}, pages = {156 -- 163}, publisher = {Wiley-Blackwell}, title = {{Relationship between neurokinin-1 receptor and substance P in the striatum: Light and electron microscopic immunohistochemical study in the rat}}, doi = {10.1002/(SICI)1096-9861(20000306)418:2<156::AID-CNE3>3.0.CO;2-Z}, volume = {418}, year = {2000}, } @article{2600, abstract = {The synaptic relationship between substance P (SP) and its receptor, i.e. neurokinin-1 receptor (NK1R), was examined in the superficial laminae of the caudal subnucleus of the spinal trigeminal nucleus (medullary dorsal horn; MDH) of the rat. For confocal laser-scanning microscopy, double-immunofluorescence histochemistry for NK1 and SP was performed. In electron microscopic double-immunolabeling study, immunoreactivity for NK1R was detected with the silver-intensified gold method, while immunoreactivity for SP was detected with peroxidase immunohistochemistry. SP-immunoreactive axon terminals were observed to be in synaptic (mostly asymmetric) contact with NK1R-immunoreactive neuronal profiles in lamina I and lamina IIo. Although some SP-immunoreactive axon terminals were in synaptic contact with NK1R-immunoreactive sites of plasma membranes, NK1R-immunoreactivity was observed at both synaptic and non-synaptic sites of plasma membrane. Thus, SP released from axon terminals might not only act on NK1Rs facing the SP-containing axon terminals, but also diffuse in the extracellular fluid for distances larger than the synaptic cleft to act on NK1Rs at some distances from the synaptic sites. }, author = {Li, Jin and Wang, Dan and Kaneko, Takeshi and Shigemoto, Ryuichi and Nomura, Sakashi and Mizuno, Noboru}, issn = {0168-0102}, journal = {Neuroscience Research}, number = {4}, pages = {327 -- 334}, publisher = {Elsevier}, title = {{The relationship between neurokinin-1 receptor and substance P in the medullary dorsal horn: A light and electron microscopic immunohistochemical study in the rat}}, doi = {10.1016/S0168-0102(00)00095-X}, volume = {36}, year = {2000}, } @article{2601, abstract = {Targeted deletion of metabotropic glutamate receptor-subtype 1 (mGluR1) gene can cause defects in development and function in the cerebellum. We introduced the mGluR1α transgene into mGluR1-null mutant [mGluR1 (-/-)] mice with a Purkinje cell (PC)-specific promoter. mGluR1-rescue mice showed normal cerebellar long-term depression and regression of multiple climbing fiber innervation, events significantly impaired in mGluR1 (-/-) mice. The impaired motor coordination was rescued by this transgene, in a dose-dependent manner. We propose that mGluR1 in PCs is a key molecule for normal synapse formation, synaptic plasticity, and motor control in the cerebellum.}, author = {Ichise, Taeko and Kano, Masanobu and Hashimoto, Kouichi and Yanagihara, Dai and Nakao, Kazuki and Shigemoto, Ryuichi and Katsuki, Motoya and Aiba, Atsu}, issn = {0036-8075}, journal = {Science}, number = {5472}, pages = {1832 -- 1835}, publisher = {American Association for the Advancement of Science}, title = {{mGluR1 in cerebellar Purkinje cells essential for long-term depression, synapse elimination, and motor coordination}}, doi = {10.1126/science.288.5472.1832}, volume = {288}, year = {2000}, } @article{2602, abstract = {Although presynaptic localization of mGluR7 is well established, the mechanism by which the receptor may control Ca2+ channels in neurons is still unknown. We show here that cultured cerebellar granule cells express native metabotropic glutamate receptor type 7 (mGluR7) in neuritic processes, whereas transfected mGluR7 was also expressed in cell bodies. This allowed us to study the effect of the transfected receptor on somatic Ca2+ channels. In transfected neurons, mGuR7 selectively inhibited P/Q-type Ca2+ channels. The effect was mimicked by GTPγS and blocked by pertussis toxin (PTX) or a selective antibody raised against the G-protein αo subunit, indicating the involvement of a G(o)-like protein. The mGuR7 effect did not display the characteristics of a direct interaction between G-protein βγ subunits and the α1A Ca2+ channel subunit, but was abolished by quenching βγ subunits with specific intracellular peptides. Intracellular dialysis of G-protein βγ subunits did not mimic the action of mGluR7, suggesting that both G-protein βγ and αo subunits were required to mediate the effect. Inhibition of phospholipase C (PLC) blocked the inhibitory action of mGluR7, suggesting that a coincident activation of PLC by the G-protein βγ with αo subunits was required. The Ca2+ chelator BAPTA, as well as inhibition of either the inositol trisphosphate (IP3) receptor or protein kinase C (PKC) abolished the mGluR7 effect. Moreover, activation of native mGluR7 induced a PTX-dependent IP3 formation. These results indicated that IP3-mediated intracellular Ca2+ release was required for PKC-dependent inhibition of the Ca2+ channels. Possible control of synaptic transmission by the present mechanisms is discussed.}, author = {Perroy, Julie and Prezèau, Laurent and De Waard, Michel and Shigemoto, Ryuichi and Bockaërt, Joël and Fagni, Laurent}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {21}, pages = {7896 -- 7904}, publisher = {Society for Neuroscience}, title = {{Selective blockade of P/Q-type calcium channels by the metabotropic glutamate receptor type 7 involves a phospholipase C pathway in neurons}}, doi = {10.1523/JNEUROSCI.20-21-07896.2000}, volume = {20}, year = {2000}, } @article{2603, abstract = {Aggregation of neurotransmitter receptors at pre- and postsynaptic structures is crucial for efficient neuronal communication. In contrast to the wealth of information about postsynaptic specializations, little is known about the molecular organization of presynaptic membrane proteins. We show here that the metabotropic glutamate receptor mGluR7a, which localizes specifically to presynaptic active zones, interacts in vitro and in vivo with PICK1. Coexpression in heterologous systems induces coclustering dependent upon the extreme C terminus of mGluR7a and the PDZ domain of PICK1. mGluR7a and PICK1 localize to excitatory synapses in hippocampal neurons. Furthermore, whereas transfected mGluR7a clusters at presynaptic sites, mGluR7aΔ3 lacking the PICK1 binding site targets to axons but does not cluster. These results suggest that PICK1 is a component of the presynaptic machinery involved in mGlUR7a aggregation and in modulation of glutamate neurotransmission.}, author = {Boudin, Hélène and Doan, Andrew and Xia, Jun and Shigemoto, Ryuichi and Huganir, Richard and Worley, Paul and Craig, Ann}, issn = {0896-6273}, journal = {Neuron}, number = {2}, pages = {485 -- 497}, publisher = {Elsevier}, title = {{Presynaptic clustering of mGluR7a requires the PICK1 PDZ domain binding site}}, doi = {10.1016/S0896-6273(00)00127-6}, volume = {28}, year = {2000}, } @inbook{2710, abstract = {In this paper we describe an intrinsically geometric way of producing magnetic fields on §3 and $\R^3$ for which the corresponding Dirac operators have a non-trivial kernel. In many cases we are able to compute the dimension of the kernel. In particular we can give examples where the kernel has any given dimension. This generalizes the examples of Loss and Yau (Commun. Math. Phys. 104 (1986) 283-290).}, author = {Erdös, László}, booktitle = {Differential Equations and Mathematical Physics}, isbn = {9780821821572}, pages = {111 -- 119}, publisher = {American Mathematical Society}, title = {{The kernel of Dirac operators on S3 and R3}}, doi = {10.1090/amsip/016}, volume = {16}, year = {2000}, } @article{2731, abstract = {We study the time evolution of a quantum particle in a Gaussian random environment. We show that in the weak coupling limit the Wigner distribution of the wave function converges to a solution of a linear Boltzmann equation globally in time. The Boltzmann collision kernel is given by the Born approximation of the quantum differential scattering cross section.}, author = {Erdös, László and Yau, Horng}, issn = {0010-3640}, journal = {Communications on Pure and Applied Mathematics}, number = {6}, pages = {667 -- 735}, publisher = {Wiley-Blackwell}, title = {{Linear Boltzmann equation as the weak coupling limit of a random Schrödinger equation}}, doi = {10.1002/(SICI)1097-0312(200006)53:6<667::AID-CPA1>3.0.CO;2-5}, volume = {53}, year = {2000}, } @article{2732, abstract = {We consider a quantum particle moving in a harmonic exterior potential and linearly coupled to a heat bath of quantum oscillators. Caldeira and Leggett derived the Fokker Planck equation with friction for the Wigner distribution of the particle in the large-temperature limit: however, their (nonrigorous) derivation was not free of criticism, especially since the limiting equation is not of Lindblad form. In this paper we recover the correct form of their result in a rigorous way. We also point out that the source of the diffusion is physically restrictive under this scaling. We investigate the model at a fixed temperature and in the large-time limit, where the origin of the diffusion is a cumulative effect of many resonant collisions. We obtain a heat equation with a friction term for the radial process in phase space and we prove the Einstein relation in this case.}, author = {Castella, François and Erdös, László and Frommlet, Florian and Markowich, Peter}, issn = {0022-4715}, journal = {Journal of Statistical Physics}, number = {3-4}, pages = {543 -- 601}, publisher = {Springer}, title = {{Fokker-Planck equations as scaling limits of reversible quantum systems}}, doi = {10.1023/A:1018667323830}, volume = {100}, year = {2000}, } @article{2733, abstract = {The Li-Yau semiclassical lower bound for the sum of the first N eigenvalues of the Dirichlet–Laplacian is extended to Dirichlet–Laplacians with constant magnetic fields. Our method involves a new diamagnetic inequality for constant magnetic fields.}, author = {Erdös, László and Loss, Michael and Vougalter, Vitali}, issn = {0373-0956}, journal = {Annales de l'Institut Fourier}, number = {3}, pages = {891 -- 907}, publisher = {Association des Annales de l'Institut Fourier}, title = {{Diamagnetic behavior of sums Dirichlet eigenvalues}}, doi = {10.5802/aif.1777}, volume = {50}, year = {2000}, } @article{3149, abstract = {The prohormone convertases (PCs) are an evolutionarily ancient group of proteases required for the maturation of neuropeptide and peptide hormone precursors. In Drosophila melanogaster, the homolog of prohormone convertase 2, dPC2 (amontillado), is required for normal hatching behavior, and immunoblotting data indicate that flies express 80- and 75-kDa forms of this protein. Because mouse PC2 (mPC2) requires 7B2, a helper protein for productive maturation, we searched the fly data base for the 7B2 signature motif PPNPCP and identified an expressed sequence tag clone encoding the entire open reading frame for this protein. dPC2 and d7B2 cDNAs were subcloned into expression vectors for transfection into HEK-293 cells; mPC2 and rat 7B2 were used as controls. Although active mPC2 was detected in medium in the presence of either d7B2 or r7B2, dPC2 showed no proteolytic activity upon coexpression of either d7B2 or r7B2. Labeling experiments showed that dPC2 was synthesized but not secreted from HEK-293 cells. However, when dPC2 and either d7B2 or r7B2 were coexpressed in Drosophila S2 cells, abundant immunoreactive dPC2 was secreted into the medium, coincident with the appearance of PC2 activity. Expression and secretion of dPC2 enzyme activity thus appears to require insect cell-specific posttranslational processing events. The significant differences in the cell biology of the insect and mammalian enzymes, with 7B2 absolutely required for secretion of dPC2 and zymogen conversion occurring intracellularly in the case of dPC2 but not mPC2, support the idea that the Drosophila enzyme has specific requirements for maturation and secretion that can be met only in insect cells.}, author = {Hwang, Jae and Siekhaus, Daria E and Fuller, Robert and Taghert, Paul and Lindberg, Iris}, issn = {0021-9258}, journal = {Journal of Biological Chemistry}, number = {23}, pages = {17886 -- 17893}, publisher = {American Society for Biochemistry and Molecular Biology}, title = {{Interaction of Drosophila melanogaster prohormone convertase 2 and 7B2: Insect cell specific processing and secretion}}, doi = {10.1074/jbc.M000032200 }, volume = {275}, year = {2000}, } @article{3489, abstract = {We have examined factors that determine the strength and dynamics of GABAergic synapses between interneurons [dentate gyrus basket cells (BCs)] and principal neurons [dentate gyrus granule cells (GCs)] using paired recordings in rat hippocampal slices at 34°C. Unitary IPSCs recorded from BC–GC pairs in high intracellular Cl− concentration showed a fast rise and a biexponential decay, with mean time constants of 2 and 9 msec. The mean quantal conductance change, determined directly at reduced extracellular Ca2+/Mg2+concentration ratios, was 1.7 nS. Quantal release at the BC–GC synapse occurred with short delay and was highly synchronized. Analysis of IPSC peak amplitudes and numbers of failures by multiple probability compound binomial analysis indicated that synaptic transmission at the BC–GC synapse involves three to seven release sites, each of which releases transmitter with high probability (∼0.5 in 2 mMCa2+/1 mM Mg2+). Unitary BC–GC IPSCs showed paired-pulse depression (PPD); maximal depression, measured for 10 msec intervals, was 37%, and recovery from depression occurred with a time constant of 2 sec. Paired-pulse depression was mainly presynaptic in origin but appeared to be independent of previous release. Synaptic transmission at the BC–GC synapse showed frequency-dependent depression, with half-maximal decrease at 5 Hz after a series of 1000 presynaptic action potentials. The relative stability of transmission at the BC–GC synapse is consistent with a model in which an activity-dependent gating mechanism reduces release probability and thereby prevents depletion of the releasable pool of synaptic vesicles. Thus several mechanisms converge on the generation of powerful and sustained transmission at interneuron–principal neuron synapses in hippocampal circuits.}, author = {Kraushaar, Udo and Jonas, Peter M}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {15}, pages = {5594 -- 5607}, publisher = {Society for Neuroscience}, title = {{Efficacy and stability of quantal GABA release at a hippocampal interneuron-principal neuron synapse}}, doi = {10.1523/JNEUROSCI.20-15-05594.2000}, volume = {20}, year = {2000}, }