The approximate swap and mismatch edit distance

There is no known algorithm that solves the general case of the approximate edit distance problem, where the edit operations are insertion, deletion, mismatch, and swap, in time o(nm), where n is the length of the text and m is the length of the pattern.In the effort to study this problem, the edit operations have been analyzed independently. Karloff [10] showed an algorithm that approximates the edit distance problem with only the mismatch operation in time . Amir et al. [4] showed that if the only edit operations allowed are swap and mismatch, then the exact edit distance problem can be solved in time .In this paper, we discuss the problem of approximate edit distance with swap and mismatch. We show a randomized time algorithm for the problem. The algorithm guarantees an approximation factor of (1+?) with probability of at least .     

Preprocess, Set, Query!

Thorup and Zwick (J. ACM 52(1):1–24, 2005 and STOC’01) in their seminal work introduced the notion of distance oracles. Given an n-vertex weighted undirected graph with m edges, they show that for any integer k≥1 it is possible to preprocess the graph in $\tilde {O}(mn^{1/k})$ time and generate a compact data structure of size O(kn ^1+1/k ). For each pair of vertices, it is then possible to retrieve an estimated distance with multiplicative stretch 2k?1 in O(k) time. For k=2 this gives an oracle of O(n ^1.5) size that produces in constant time estimated distances with stretch 3. Recently, Pǎtra?cu and Roditty (In: Proc. of 51st FOCS, 2010) broke the theoretical status-quo in the field of distance oracles and obtained a distance oracle for sparse unweighted graphs of O(n ^5/3) size that produces in constant time estimated distances with stretch 2. In this paper we show that it is possible to break the stretch 2 barrier at the price of non-constant query time in unweighted undirected graphs. We present a data structure that produces estimated distances with 1+ε stretch. The size of the data structure is O(nm ^1?ε′) and the query time is $\tilde {O}(m^{1-\varepsilon '})$ . Using it for sparse unweighted graphs we can get a data structure of size O(n ^1.87) that can supply in O(n ^0.87) time estimated distances with multiplicative stretch 1.75.     

Approximate Pattern Matching with the <Emphasis Type="Italic">L</Emphasis><Subscript>1</Subscript>, <Emphasis Type="Italic">L</Emphasis><Subscript>2</Subscript> and <Emphasis Type="Italic">L</Emphasis><Subscript>∞</Subscript> Metrics

Given an alphabet Σ={1,2,…,|Σ|} text string T∈Σ ⁿ and a pattern string P∈Σ ^m , for each i=1,2,…,n−m+1 define L _p (i) as the p-norm distance when the pattern is aligned below the text and starts at position i of the text. The problem of pattern matching with L _p distance is to compute L _p (i) for every i=1,2,…,n−m+1. We discuss the problem for d=1,2,∞. First, in the case of L ₁ matching (pattern matching with an L ₁ distance) we show a reduction of the string matching with mismatches problem to the L ₁ matching problem and we present an algorithm that approximates the L ₁ matching up to a factor of 1+ε, which has an O(\frac1e²nlogmlog|S|)O(\frac{1}{\varepsilon^{2}}n\log m\log|\Sigma|) run time. Then, the L ₂ matching problem (pattern matching with an L ₂ distance) is solved with a simple O(nlog m) time algorithm. Finally, we provide an algorithm that approximates the L _∞ matching up to a factor of 1+ε with a run time of O(\frac1enlogmlog|S|)O(\frac{1}{\varepsilon}n\log m\log|\Sigma|) . We also generalize the problem of String Matching with mismatches to have weighted mismatches and present an O(nlog ⁴ m) algorithm that approximates the results of this problem up to a factor of O(log m) in the case that the weight function is a metric.     

Summarizing stories after reading and listening.

48 college students either listened to or read 3 tape-recorded stories, each about 2,000 words in length. Immediately after processing each story, Ss wrote a summary in 60–80 words. A comparison of the summaries written after reading with those written after listening revealed only minor differences. Ss tended to include a little more idiosyncratic detail in their summaries after listening than after reading, but the shared content of the summaries remained remarkably unchanged. It is concluded that these results can aid in the identification of the common core of comprehension processes that underlie both listening and skilled reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of Industrial conflict.

The subject of industrial conflict is so broad that one would hope for its treatment to be lengthy, interdisciplinary, and to encompass many specific topics and viewpoints. As such, this book, written under the sponsorship of SPSSI, meets all one's expectations. It sets out with the ambitious purposes of analyzing the determining factors and conditions which give rise to industrial conflict and of assessing various efforts of solution. The book is divided into five main parts: (a) basic issues concerning industrial conflict; (b) roots of industrial conflict (motivational analysis, organization and leadership of groups in conflict, social and economic influences); (c) dealing with industrial conflict (accommodating to conflict, efforts to remove sources of conflict, social control of industrial conflict); (d) industrial conflict in other societies, and (e) Industrial conflict, present and future. Thirty-nine different authors, including academicians, writers, labor leaders, and industrial representatives, have contributed to the book's forty chapters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phosphorus and potassium cycling in a long-term no-till integrated soybean-beef cattle production system under different grazing intensities insubtropics

Long-term integrated crop-livestock system enables constant and more efficient nutrient cycling because animal, pasture and crop residues release nutrients at different rates. Therefore, appropriate management of these systems is needed to maximize benefits from nutrient cycling. The objective of this study was to evaluate how grazing intensity affected the release rates of phosphorus (P) and potassium (K) in pasture, dung and soybean residues in a no-till long-term integrated crop-livestock system. The experiment was established in 2001 on a clayey Oxisol after soybean harvest. Treatments consisted of pasture with sward heights maintained at 1020, 30 and 40 cm by different cattle stocking rates and a non-grazed (NG) treatment. Decomposition and release rates of nutrients in the pasture and dung were determined using litter bags, which were installed at soybean seeding and pasture seeding during two pasture-crop cycles (2009–2011). Lighter grazing intensities resulted in greater P release rate from pasture and dung residues. Pasture and dung residues released K at a very high rate and were not influenced by grazing intensity. The P and K released from soybean residue were not affected by grazing intensity; however, decomposition of soybean leaves was greater than of stems. Greatest rates of total P and K released were from pasture and dung residues under lighter grazing intensities and in the NG areas. Large amounts of P (~25 kg ha^?1) and K (~130–180 kg ha^?1) were cycled in a complete soybean-beef cattle integrated system and must be considered in the fertilization management.     

Approximate string matching with address bit errors

A string S∈Σ^m$S\in {\Sigma }^m$ can be viewed as a set of pairs S={(_σi,i):i∈{0,…,m−1}}$S=\{({\sigma }_i,i):i\in \{0,\dots ,m-1\}\}$. We consider approximate pattern matching problems arising from the setting where errors are introduced to the location component (i$i$), rather than the more traditional setting, where errors are introduced into the content itself (_σi${\sigma }_i$). In this paper, we consider the case where bits of i$i$ may be erroneously flipped, either in a consistent or transient manner. We formally define the corresponding approximate pattern matching problems, and provide efficient algorithms for their resolution, while introducing some novel techniques.     

Investigation of the dominant point defects in tetragonal YBa2Cu3Ox at elevated temperatures

The manner in which oxygen is incorporated into YBa₂Cu₃O _x (YBCO) at 800°C for values ofx close to 6 is shown to be in the form of neutral oxygen interstitials, O _i ^x . The experimental data on which this conclusion is based are obtained from measurements of oxygen partial pressure,P(O₂), as a function of compositionx and temperatureT (5.99x 6.35, 825T1120 K). The data are obtained by a solid-state electrochemical method. Other conclusions of this study include: (a) O _i ^x are noninteracting forx 6. (b) The stoichiometric composition of YBCO isx 6.0. (c) The reaction enthalpy of oxidation is 179 kJ/mol O₂. (d) The Fermi level changes by –0.2 eV asx increases from 6.05 to 6.35.     

PCR-based gene synthesis as an efficient approach for expression of the A+T-rich malaria genome

The A+T-rich genome of the human malaria parasite Plasmodiumfalciparum encodes genes of biological importance that cannotbe expressed efficiently in heterologous eukaryotic systems,owing to an extremely biased codon usage and the presence ofnumerous cryptic polyadenylation sites. In this work we haveoptimized an assembly polymerase chain reaction (PCR) methodfor the fast and extremely accurate synthesis of a 2.1 kb Plasmodiumfalciparum gene (pfsub-1) encoding a subtilisin-like protease.A total of 104 oligonucleotides, designed with the aid of dedicatedcomputer software, were assembled in a single-step PCR. Theassembly was then further amplified by PCR to produce a syntheticgene which has been cloned and successfully expressed in bothPichia pastoris and recombinant baculovirus-infected High Five^TMcells. We believe this strategy to be of special interest asit is simple, accessible and has no limitation with respectto the size of the gene to be synthesized. Used as a systematicapproach for the malarial genome or any other A + T-rich organism,the method allows the rapid synthesis of a nucleotide sequenceoptimized for expression in the system of choice and productionof sufficiently large amounts of biological material for completemolecular and structural characterization.