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Easton, PA, United States

Lafayette College is a private coeducational liberal arts and engineering college located in Easton, Pennsylvania, USA. The school, founded in 1826 by James Madison Porter, son of General Andrew Porter of Norristown and the citizens of Easton, first began holding classes in 1832. The founders voted to name the school after General Lafayette, who famously toured the country in 1824–25, as "a testimony of respect for talents, virtues, and signal services... in the great cause of freedom".Located on College Hill in Easton, the campus is situated in the Lehigh Valley, about 70 mi west of New York City and 60 mi north of Philadelphia. Lafayette College guarantees campus housing to all enrolled students. The school requires students to live in campus housing unless approved for residing in private off-campus housing or home as a commuter.The student body, consisting entirely of undergraduates, comes from 42 U.S. states and 37 countries. Students at Lafayette are involved in over 250 clubs and organizations including athletics, fraternities and sororities, special interest groups, community service clubs and honor societies. Lafayette College's athletic program is notable for The Rivalry with nearby Lehigh University. Since 1884, the two football teams have met 150 times, making it the most played rivalry in the history of college football. Wikipedia.

Sherma J.,Lafayette College
Central European Journal of Chemistry | Year: 2014

The most important advances in planar chromatography published between November 1, 2011 and November 1, 2013 are reviewed in this paper. Included are an introduction to the current status of the field; student experiments, books, and reviews; theory and fundamental studies; apparatus and techniques for sample preparation and TLC separations (sample application and plate development with the mobile phase); detection and identification of separated zones (chemical and biological detection, TLC/mass spectrometry, and TLC coupled with other spectrometric methods); techniques and instruments for quantitative analysis; preparative layer chromatography; and thin layer radiochromatography. Numerous applications to a great number of compound types and sample matrices are presented in all sections of the review. © 2014 Versita Warsaw and Springer-Verlag Wien. Source

Traldi L.,Lafayette College
Combinatorics Probability and Computing | Year: 2010

The interlace polynomials introduced by Arratia, Bollobs and Sorkin extend to invariants of graphs with vertex weights, and these weighted interlace polynomials have several novel properties. One novel property is a version of the fundamental three-term formula q(G)=q(G-a)+q(Gab-b)+((x-1)^ 2-1)q(Gab-a-b) that lacks the last term. It follows that interlace polynomial computations can be represented by binary trees rather than mixed binary-ternary trees. Binary computation trees provide a description of q(G) that is analogous to the activities description of the Tutte polynomial. If G is a tree or forest then these algorithmic activities are associated with a certain kind of independent set in G. Three other novel properties are weighted pendant-twin reductions, which involve removing certain kinds of vertices from a graph and adjusting the weights of the remaining vertices in such a way that the interlace polynomials are unchanged. These reductions allow for smaller computation trees as they eliminate some branches. If a graph can be completely analysed using pendant-twin reductions, then its interlace polynomial can be calculated in polynomial time. An intuitively pleasing property is that graphs which can be constructed through graph substitutions have vertex-weighted interlace polynomials which can be obtained through algebraic substitutions. © 2009 Cambridge University Press. Source

Traldi L.,Lafayette College
European Journal of Combinatorics | Year: 2011

A theorem of Cohn and Lempel [M. Cohn, A. Lempel, Cycle decomposition by disjoint transpositions, J. Combin. Theory Ser. A 13 (1972) 83-89] gives an equality relating the number of circuits in a directed circuit partition of a 2-in, 2-out digraph to the GF(2)-nullity of an associated matrix. This equality is essentially equivalent to the relationship between directed circuit partitions of 2-in, 2-out digraphs and vertex-nullity interlace polynomials of interlace graphs. We present an extension of the Cohn-Lempel equality that describes arbitrary circuit partitions in (undirected) 4-regular graphs. The extended equality incorporates topological results that have been of use in knot theory, and it implies that if H is obtained from an interlace graph by attaching loops at some vertices then the vertex-nullity interlace polynomial qN(H) is essentially the generating function for certain circuit partitions of an associated 4-regular graph. © 2011 Elsevier Ltd. Source

Traldi L.,Lafayette College
Journal of Combinatorial Theory. Series B | Year: 2013

The generating function that records the sizes of directed circuit partitions of a connected 2-in, 2-out digraph D can be determined from the interlacement graph of D with respect to a directed Euler circuit; the same is true of the generating functions for other kinds of circuit partitions. The interlace polynomials of Arratia, Bollobás and Sorkin [R. Arratia, B. Bollobás, G.B. Sorkin, The interlace polynomial of a graph, J. Combin. Theory Ser. B 92 (2004) 199-233; R. Arratia, B. Bollobás, G.B. Sorkin, A two-variable interlace polynomial, Combinatorica 24 (2004) 567-584] extend the corresponding functions from interlacement graphs to arbitrary graphs. We introduce a multivariate interlace polynomial that is an analogous extension of a multivariate generating function for undirected circuit partitions of undirected 4-regular graphs. The multivariate polynomial incorporates several different interlace polynomials that have been studied by different authors, and its properties include invariance under a refined version of local complementation and a simple recursive definition. © 2012 Elsevier Inc. Source

Weisberg J.M.,Carleton College | Nice D.J.,Lafayette College | Taylor J.H.,Princeton University
Astrophysical Journal | Year: 2010

We present results of more than three decades of timing measurements of the first known binary pulsar, PSR B1913+16. Like most other pulsars, its rotational behavior over such long timescales is significantly affected by small-scale irregularities not explicitly accounted for in a deterministic model. Nevertheless, the physically important astrometric, spin, and orbital parameters are well determined and well decoupled from the timing noise. We have determined a significant result for proper motion, μα = - 1.43 ±0.13,μδ =-0.70 ±0.13 mas yr-1. The pulsar exhibited a small timing glitch in 2003 May, with Δf/f = 3.7 × 10-11, and a smaller timing peculiarity in mid-1992. A relativistic solution for orbital parameters yields improved mass estimates for the pulsar and its companion, m1 = 1.4398 ± 0.0002 M⊙ and m2 = 1.3886 ± 0.0002 M⊙. The system's orbital period has been decreasing at a rate 0.997 ± 0.002 times that predicted as a result of gravitational radiation damping in general relativity. As we have shown before, this result provides conclusive evidence for the existence of gravitational radiation as predicted by Einstein's theory. © 2010. The American Astronomical Society. Source

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