ON TOPOLOGICAL 2D2D STRING AND INTERSECTION THEORY

The topological description of $2D$ string theory at the self-dual radius is studied in the algebro-geometrical formulation of the $A_{k+1}$ topological models at $k=-3$. Genus zero correlators of tachyons and their gravitational descendants are computed as intersection numbers on moduli space and compared to $2D$ string results. The interpretation of negative momentum tachyons as gravitational descendants of the cosmological constant, as well as modifications of this, is shown to imply a disagreement between $2D$ string correlators and the associated intersection numbers.Comment: Latex, 10 pages, no figure

Érôs chez Platon

Lorsque retentira l’heure ultime du mondeLa terre volera en multiples éclatsTout le visible alors s’engloutira dans l’ondeLe visage de Dieu seul s’y reflétera !Tiouttchev. I Plus que toute autre époque, notre modernité aspire à la synthèse. L’impuissance qui frappe aujourd’hui la pensée philosophique et la nostalgie qu’elle éprouve pour une synthèse suprême sont le prix qu’elle doit payer pour racheter la confiance ave..

The time travel paradox

We define the time travel paradox in physical terms and prove its existence by constructing an explicit example. We argue further that in theories -- such as general relativity -- where the spacetime geometry is subject to nothing but differential equations and initial data no paradoxes arise.Comment: Minor changes + an explanatory note concerning the lions with the same world line

(1,q=−1)(1,q=-1) Model as a Topological Description of 2d2d String Theory

We study the $(1,q=-1)$ model coupled to topological gravity as a candidate to describing $2d$ string theory at the self-dual radius. We define the model by analytical continuation of $q>1$ topological recursion relations to $q=-1$. We show that at genus zero the $q=-1$ recursion relations yield the $W_{1+\infty}$ Ward identities for tachyon correlators on the sphere. A scheme for computing correlation functions of $q=-1$ gravitational descendants is proposed and applied for the computation of several correlators. It is suggested that the latter correspond to correlators of discrete states of the $c=1$ string. In a similar manner to the $q>1$ models, we show that there exist topological recursion relations for the correlators in the $q=-1$ theory that consist of only one and two splittings of the Riemann surface. Using a postulated regularized contact, we prove that the genus one $q=-1$ recursion relations for tachyon correlators coincide with the $W_{1+\infty}$ Ward identities on the torus. We argue that the structure of these recursion relations coincides with that of the $W_{1+\infty}$ Ward identities for any genus.Comment: 39 pages,latex,taup-2170 -9

On the Algebraic Structure of Gravitational Descendants in CP(n-1) Coset Models

We investigate how specific free-field realizations of twisted N=2 supersymmetric coset models give rise to natural extensions of the ``matter'' Hilbert spaces in such a manner as to incorporate the various gravitational excitations. In particular, we show that adopting a particular screening prescription is equivalent to imposing the requisite equivariance condition on cohomology. We find a simple algebraic characterization of the $W_n$-gravitational ground ring spectra of these theories in terms of affine-$SU(n)$ highest weights..Comment: 12p, harvmac/lanlmac with hyperlinks, 1 uuencoded PostScript figure, CERN-TH.7442/94, USC-94/01

The existence of superluminal particles is consistent with the kinematics of Einstein's special theory of relativity

Within an axiomatic framework of kinematics, we prove that the existence of faster than light particles is logically independent of Einstein's special theory of relativity. Consequently, it is consistent with the kinematics of special relativity that there might be faster than light particles.Comment: 19 pages, 3 figure

A note on instanton counting for N=2 gauge theories with classical gauge groups

We study the prepotential of N=2 gauge theories using the instanton counting techniques introduced by Nekrasov. For the SO theories without matter we find a closed expression for the full prepotential and its string theory gravitational corrections. For the more subtle case of Sp theories without matter we discuss general features and compute the prepotential up to instanton number three. We also briefly discuss SU theories with matter in the symmetric and antisymmetric representations. We check all our results against the predictions of the corresponding Seiberg-Witten geometries.Comment: 24 pages, LaTeX. v2: refs added. v3: typos correcte

PLANdbAffy: probe-level annotation database for Affymetrix expression microarrays

Standard Affymetrix technology evaluates gene expression by measuring the intensity of mRNA hybridization with a panel of the 25-mer oligonucleotide probes, and summarizing the probe signal intensities by a robust average method. However, in many cases, signal intensity of the probe does not correlate with gene expression. This could be due to the hybridization of the probe to a transcript of another gene, mapping of the probe to an intron, alternative splicing, single nucleotide polymorphisms and other reasons. We have developed a database, PLANdbAffy (available at http://affymetrix2.bioinf.fbb.msu.ru), that contains the results of the alignment of probe sequences from five Affymetrix expression microarrays to the human genome. We have determined the probes matching the transcript-coding regions in the correct orientation. For each such probe alignment region, we determined the mRNA and EST sequences that contain the probe sequence. In the textual part of the database interface we summarize the data on the sequences that cover the probe alignment region and SNPs that are located inside it. The graphical part of our database interface is implemented as custom tracks to the UCSC genome browser that allows one to utilize all the data that are offered by UCSC browser

The Role of Avalanches in Mass Budget of Glaciers

International Conference on Low Temperature Science. I. Conference on Physics of Snow and Ice, II. Conference on Cryobiology. (August, 14-19, 1966, Sapporo, Japan