943 research outputs found

    Study Of Pits And Fissures On Occlusal Surfaces Of Human Teeth

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    The northernmost record of the blue-spotted cornetfish from the Mediterranean Sea

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    A school of Fistularia commersonii was sighted off Laigueglia (Italy), Northwestern Ligurian Sea, inAugust 2008. This fast spreading invasive Indo-Pacific fish was first recorded in the Mediterranean fromIsrael, and it has since spread clear across the sea. This is the northernmost record from the Mediterranean

    Biodiversity impacts of ship movement, noise, grounding and anchoring

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    Marine life in the Mediterranean Sea is threatened by intensive human activities such as fisheries, ship traffic, pollution and coastal development. Cetaceans and other vertebrates are affected not only by chemical pollution, but also by noise pollution (Richardson et al., 1995; Simmonds et al., 2004). Noise has become a ubiquitous form of marine pollution, especially in areas of heavy maritime traffic and along developed coasts. Intense underwater noise is generated by airguns, widely used for geophysical exploration in the oil and gas industry as well as for academic and government research purposes; by high power sonar, either military or civilian; by ship traffic; by shoreline and offshore construction works; and by a number of other commercial, scientific, military and industrial sources. The most powerful noises (from airguns, sonars, and explosions) may directly injure animals in the vicinity of the source. General ship traffic, heavy industries on the coast and a variety of other human activities generally do not generate such intense noise, but the acoustic pollution they produce is constant over time and may affect large areas. It may be a serious hazard not only to individual animals, but also to entire populations. Such increased background noise affects underwater life just as airborne noise affects terrestrial animals, including human beings.peer-reviewe

    Ternary Syndrome Decoding with Large Weight

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    The Syndrome Decoding problem is at the core of many code-based cryptosystems. In this paper, we study ternary Syndrome Decoding in large weight. This problem has been introduced in the Wave signature scheme but has never been thoroughly studied. We perform an algorithmic study of this problem which results in an update of the Wave parameters. On a more fundamental level, we show that ternary Syndrome Decoding with large weight is a really harder problem than the binary Syndrome Decoding problem, which could have several applications for the design of code-based cryptosystems

    Pattern Matching in Multiple Streams

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    We investigate the problem of deterministic pattern matching in multiple streams. In this model, one symbol arrives at a time and is associated with one of s streaming texts. The task at each time step is to report if there is a new match between a fixed pattern of length m and a newly updated stream. As is usual in the streaming context, the goal is to use as little space as possible while still reporting matches quickly. We give almost matching upper and lower space bounds for three distinct pattern matching problems. For exact matching we show that the problem can be solved in constant time per arriving symbol and O(m+s) words of space. For the k-mismatch and k-difference problems we give O(k) time solutions that require O(m+ks) words of space. In all three cases we also give space lower bounds which show our methods are optimal up to a single logarithmic factor. Finally we set out a number of open problems related to this new model for pattern matching.Comment: 13 pages, 1 figur

    Palindromic Decompositions with Gaps and Errors

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    Identifying palindromes in sequences has been an interesting line of research in combinatorics on words and also in computational biology, after the discovery of the relation of palindromes in the DNA sequence with the HIV virus. Efficient algorithms for the factorization of sequences into palindromes and maximal palindromes have been devised in recent years. We extend these studies by allowing gaps in decompositions and errors in palindromes, and also imposing a lower bound to the length of acceptable palindromes. We first present an algorithm for obtaining a palindromic decomposition of a string of length n with the minimal total gap length in time O(n log n * g) and space O(n g), where g is the number of allowed gaps in the decomposition. We then consider a decomposition of the string in maximal \delta-palindromes (i.e. palindromes with \delta errors under the edit or Hamming distance) and g allowed gaps. We present an algorithm to obtain such a decomposition with the minimal total gap length in time O(n (g + \delta)) and space O(n g).Comment: accepted to CSR 201

    Detecting One-variable Patterns

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    Given a pattern p=s1x1s2x2sr1xr1srp = s_1x_1s_2x_2\cdots s_{r-1}x_{r-1}s_r such that x1,x2,,xr1{x,x}x_1,x_2,\ldots,x_{r-1}\in\{x,\overset{{}_{\leftarrow}}{x}\}, where xx is a variable and x\overset{{}_{\leftarrow}}{x} its reversal, and s1,s2,,srs_1,s_2,\ldots,s_r are strings that contain no variables, we describe an algorithm that constructs in O(rn)O(rn) time a compact representation of all PP instances of pp in an input string of length nn over a polynomially bounded integer alphabet, so that one can report those instances in O(P)O(P) time.Comment: 16 pages (+13 pages of Appendix), 4 figures, accepted to SPIRE 201

    Migration routes of the Grant's Zebra

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    This is where the abstract of this record would appear. This is only demonstration data
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