We report on the first demonstration of femtosecond x-ray absorption spectroscopy, made uniquely possible by the use of broadly tunable bending-magnet radiation from "laser-sliced" electron bunches within a synchrotron storage ring. We measure the femtosecond electronic rearrangements that occur during the photoinduced insulator-metal phase transition in VO2. Symmetry- and element-specific x-ra...

We introduce pretty clean modules, extending the notion of clean modules by Dress, and show that pretty clean modules are sequentially CohenMacaulay. We also extend a theorem of Dress on shellable simplicial complexes to multicomplexes.

The Precautionary Principle provides a framework for action to protect human health and the environment in the face of uncertainty. The central premise of the precautionary principle is that when an activity poses threats of serious, irreversible harm to human health or the environment, we should act to prevent that damage – even if science has not fully worked out the details of the relevant c...

Eccentric coloring is a new variation of coloring, where higher numbered colors can not be used as freely as lower numbered colors. In addition there is a correspondence between the eccentricity (max distance) of a vertex and the highest legal color for that vertex. In this note we investigate eccentric coloring of trees. We give the eccentric chromatic number or a bound on the eccentric chroma...

We present a study of weak lensing shear measurements for simulated galaxy images at radio wavelengths. We construct a simulation pipeline into which we can input galaxy images of known shapelet ellipticity, and with which we then simulate observations with eMERLIN and the international LOFAR array. The simulations include the effects of the CLEAN algorithm, uv sampling, observing angle, and vi...

1. Let T be a ternary ring with the ternary operation T(a, b, c) and the distinguished elements 0, 1 (see [4]). On T, two loop structures can be defined by means of the binary operations a+b = T(a, 1, b) and ab=T(a, b, 0). The resulting loops are called the additive and the multiplicative loop of Ty respectively. Together with a0 = 0a = 0 they define the structure of a double loop on T, which s...

In this paper an experimental characterization of a typical indoor wireless propagation channel is performed. This channel characterization is needed for short range applications (<10m), utilizing Ultra-Wideband Impulse Radio (UWB-IR) techniques. Both the line of sight (LOS) and the non line of sight (NLOS) scenarios are taken into account. The characterization is done using time domain measure...

This paper analysis the characteristics and ambiguity function of the single-channel and multichannel DVB-T signals, and choose the multi-channel DVB-T signal as opportunity illuminators to do the research of ISAR imaging. Firstly, the target’s echo using single-in-multi-out mode for passive ISAR image is derived, together with the analysis of the composition of the echo’s spatial spectrum. Con...

A set $Wsubset V (G)$ is called a resolving set, if for every two distinct vertices $u, v in V (G)$ there exists $win W$ such that $d(u,w) not = d(v,w)$, where $d(x, y)$ is the distance between the vertices $x$ and $y$. A resolving set for $G$ with minimum cardinality is called a metric basis. A graph with a unique metric basis is called a uniquely dimensional graph. In this paper, we establish...

Quantum yields for photochemical ring opening of six alkylcyclobutenes have been measured in hexane solution using 228-nm excitation, which selectively populates the lowest pi,R(3s) excited singlet states of these molecules and has been shown previously to lead to ring opening with clean conrotatory stereochemistry. The compounds studied in this work-1,2-dimethylcyclobutene (1), cis- and trans-...