We investigated the relationship between LiDAR and ladder fuels in the northern Sierra Nevada, California USA. Ladder fuels are often targeted in hazardous fuel reduction treatments due to their role in propagating fire from the forest floor to tree crowns. Despite their importance, ladder fuels are difficult to quantify. One common approach is to calculate canopy base height, but this has many...

A ladder lottery, known as the “Amidakuji” in Japan, is a common way to choose a permutation randomly. A ladder lottery L corresponding to a given permutation π is optimal if L has the minimum number of horizontal-lines among ladder lotteries corresponding to π. In this paper we show that for any two optimal ladder lotteries L1 and L2 of a permutation, there exists a sequence of local modificat...

For discrete multiple orthogonal polynomials such as the multiple Charlier polynomials, the multiple Meixner polynomials, and the multiple Hahn polynomials, we first find a lowering operator and then give a (r + 1)th order difference equation by combining the lowering operator with the raising operator. As a corollary, explicit third order difference equations for discrete multiple orthogonal p...

One of the main themes in the area of Terminological Reasoning has been to identify description logics (DLs) that are both very expressive and decidable. A recent paper by Schild showed that this issue can be profitably addressed by relying on a correspondence between DLs and propositional dynamic logics (PDL). However Schild left open three important problems, related to the translation into P...

We will report on new dc-free runlength-limited codes (DCRLL) intended for the next generation of DVD. The efficiency of the newly developed DCRLL schemes is extremely close to the theoretical maximum, and as a result, significant density gains can be obtained with respect to prior art coding schemes. With a newly developed DCRLL ( = 2) code we can achieve a 9% higher overall rate than that of ...

Using the modified factorization method employed by Mielnik for the harmonic oscillator, we show that isospectral structures associated with a second order operator H, can always be constructed whenever H could be factored, or exist ladder operators for its eigenfunctions. Three examples are shown, and properties like completeness and integrability are discused for the general case.

The ideals generated by pfaffians of mixed size contained in a subladder of a skew-symmetric matrix of indeterminates define arithmetically Cohen-Macaulay, projectively normal, reduced and irreducible projective varieties. We show that these varieties belong to the G-biliaison class of a complete intersection. In particular, they are glicci.

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