On Asymmetric Coverings and Covering Numbers

An asymmetric covering D(n,R) is a collection of special subsets S of an n-set such that every subset T of the n-set is contained in at least one special S with |S| - |T| <= R. In this paper we compute the smallest size of any D(n,1) for n <= 8. We also investigate ``continuous'' and ``banded'' versions of the problem. The latter involves the classical covering numbers C(n,k,k-1), and we determine the following new values: C(10,5,4) = 51, C(11,7,6,) =84, C(12,8,7) = 126, C(13,9,8)= 185 and C(14,10,9) = 259. We also find the number of nonisomorphic minimal covering designs in several cases.Comment: 11 page

Common Law Preclusion and Environmental Citizen Suits: Are Citizen Groups Losing Their Standing?

The citizen suit provision of the Clean Air Act (CAA) gives standing to citizen groups to bring suits against private actors for violations of the Act. Congress and the courts have established limitations on a citizen’s ability to bring a claim. These include notification of intent to file, a bar when the EPA or state has already “commenced and is diligently prosecuting” an action, or where the claim is barred by common law preclusion doctrines. In a divided decision, the Tenth Circuit held that the doctrine of issue preclusion barred the filing of a CAA citizen suit in Sierra Club v. Two Elk Generation Partners. The court found that the Sierra Club, the citizen group, was barred from filing a claim even though it was not a party to the previous administrative action. Through an expansive interpretation of the parens patriae doctrine, the Tenth Circuit circumvented the true purpose of the CAA’s citizen suit provisio

Polarization-resolved second-harmonic-generation optical coherence tomography in collagen

We describe a novel imaging technique, second-harmonic-generation optical coherence tomography (SHOCT). This technique combines the spatial resolution and depth penetration of optical coherence tomography (OCT) with the molecular sensitivity of second-harmonic-generation spectroscopy. As a consequence of the coherent detection required for OCT, polarization-resolved images arise naturally. We demonstrate this new technique on a skin sample from the belly of Icelandic salmon, acquiring polarization-resolved SHOCT and OCT images simultaneously

Pump-probe scheme for optical coherence tomography using indocyanine green mixed with albumin or human plasma

Use of indocyanine green (ICG) in a pump-probe scheme for OCT is proposed. The study illustrates that ICG in protein solution shows unusual pump-probe imaging potential, indicating its usefulness as a contrast agent for OCT

Spin-waves in the J1a−J1b−J2J_{1a}-J_{1b}-J_{2} orthorombic square-lattice Heisenberg models: Application to the iron pnictide materials

Motivated by the observation of spatially anisotropic exchange constants in the iron pnictide materials, we study the spin-wave spectra of the $J_{1a}-J_{1b}-J_{2}$ Heisenberg models on a square-lattice with nearest neighbor exchange $J_{1a}$ along x and $J_{1b}$ along y axis and a second neighbor exchange $J_2$. We focus on the regime, where the spins order at ($\pi,0$), and compute the spectra by systematic expansions around the Ising limit. We study both spin-half and spin-one Heisenberg models as well as a range of parameters to cover various cases proposed for the iron pnictide materials. The low-energy spectra have anisotropic spin-wave velocities and are renormalized with respect to linear spin-wave theory by up to 20 percent, depending on parameters. Extreme anisotropy, consisting of a ferromagnetic $J_{1b}=- |J_F|$, is best distinguished from a weak anisotropy ($J_{1a}\approx J_{1b}=J_1$, $J_2>J_1/2$) by the nature of the spin-waves near the wavevectors ($0,\pi$) or ($\pi,\pi$). The reported spectra for the pnictide material CaFe$_2$As$_2$ clearly imply such an extreme anisotropy.Comment: 6 pages, 10 figure

Spectral triangulation molecular contrast optical coherence tomography with indocyanine green as the contrast agent

We report a new molecular contrast optical coherence tomography (MCOCT) implementation that profiles the contrast agent distribution in a sample by measuring the agent's spectral differential absorption. The method, spectra triangulation MCOCT, can effectively suppress contributions from spectrally dependent scatterings from the sample without a priori knowledge of the scattering properties. We demonstrate molecular imaging with this new MCOCT modality by mapping the distribution of indocyanine green, a FDA-approved infrared red dye, within a stage 54 Xenopus laevis

Serotonin, Septal Lesions, and Shock-Escape Learning in Rats

An article written by Bruce A. Mattingly, James E. Gotsick and E. Brooks Applegate and published in Psychological Reports in 1986, pages 3-9

Endogenous glutathione levels modulate the frequency of both spontaneous and long wavelength ultraviolet induced mutations in human cells

Spontaneous and induced mutations at the hypoxanthine guanine phosphoribosyt transferase locus have been measured in cultured human lymphoblastoid (TK6) cell populations under conditions in which cellular glutathione has been severely depleted by overnight treatment with buthionine-S,R-sulfoximine. At maximum levels of glutathione depletion, the increase in spontaneous frequency is at least 5-fold, a finding consistent with the possibility that cellular redox state can modulate the levels of pre-mutagenic damage arising as a result of normal metabolism in cultured human cells. Glutathione depletion does not lead to a significant enhancement in the frequency of mutants that arise as a result of irradiation at 313 run but does lead to a 3-fold increase in mutations resulting from irradiation at 365 nm. These results indicate that glutathione may quench reactive intermediates that would otherwise lead to spontaneous mutations as well as a fraction of UVA radiation-induced premutagenic damag

In-Process Radiography of ARC Weld

In-process nondestructive evaluation of welds is of major importance for automated weld processing. Real-time evaluation of defect formation makes possible on-line rewelding and adjustment of process parameters. Measurements of physical parameters related to weld quality may also give information important for understanding the weld process and for improvements of weld quality. In this study we implement industrial radiography for real-time weld process monitoring and testing. X-ray penetrating radiation is used for volume observation in the welding pool and the heat-affected zone during the weld process. The advantages of such a technique are on-line testing of defect formation in the weld and the study of metal fusion and filler metal-base metal interaction, metal transfer and mass flow in the welding pool. This technique may also be used for post-service real-time remote testing of weld quality. By integrating automatic nondestructive inspection with an automatic process control system, unified manufacturing control and testing procedures can be developed. In this unit approach, the nondestructive system may be included as a part of the sensing system in the feedback loop of the process control. Research and development of such general concepts for remote weld process control using real-time radiography as a vision system was initiated in our laboratory under the sponsorship of the Edison Welding Institute