An important property of strongly regular graphs is that the second subconstituent of any primitive strongly regular graph is always connected. Brouwer asked to what extent this statement can be generalized to distanceregular graphs. In this paper, we show that if γ is any vertex of a distanceregular graph Γ and t is the index where the standard sequence corresponding to the second largest eige...

A new optimal-extraction technique has been developed for deriving point-source spectra from data taken by the Infrared Spectrograph (IRS) on-board the Spitzer Space Telescope. The new technique gives improvements of up to a factor of two in the signal-to-noise ratio (S/N) for faint (< 10 mJy) sources, corresponding to an effective quadrupling of the exposure time. Regular extraction consists o...

MOTIVATION Leucine-rich nuclear export signals (NESs) are short amino acid motifs that mediate binding of cargo proteins to the nuclear export receptor CRM1, and thus contribute to regulate the localization and function of many cellular proteins. Computational prediction of NES motifs is of great interest, but remains a significant challenge. RESULTS We have developed a novel approach for ami...

The edge-integrity of a graph G is I 0(G) := minfjSj + m(G S) : S Eg; where m(H) denotes the maximum order of a component of H: A graph G is called honest if its edge-integrity is the maximum possible, that is, equals the order of the graph. The only honest 2-regular graphs are the 3-, 4-, and 5-cycles. Lipman [13] proved that there are exactly twenty honest cubic graphs. In this paper we explo...

Let P(Σ∗) be the semiring of languages, and consider its subset P(Σ). In this paper we define the language recognized by a weighted automaton over P(Σ) and a one-letter alphabet. Similarly, we introduce the notion of language recognition by linear recurrence equations with coefficients in P(Σ). As we will see, these two definitions coincide. We prove that the languages recognized by linear recu...

Many major cities in the U.S. and throughout the world, including New York City, have areas where clusters of skyscrapers are present. Why do builders choose to build real estate with such height? And, how does the choice of height depend on characteristics of nearby buildings, demographics, and other spatial factors? Using a data set consisting of detailed information for 458 skyscrapers in Ne...