Has the Roberts Court Plurality\u27s Colorblind Rhetoric Finally Broken \u3cem\u3eBrown\u27s\u3c/em\u3e Promise?

This Essay examines the continuing significance of the Keyes decision to the judicial vision of equality and racial isolation in public education. By comparing efforts to promote educational equality from the Keyes era through today, this Essay asserts that the judiciary has wrongly embraced a colorblind interpretation of the Equal Protection Clause. In so doing, courts have impeded the progress of children in Denver and around the country, ignored highly instructive social science studies on the benefits of desegregation, and broken the constitutional promise of equal citizenship. For future policy makers and lawyers to address these persistent problems, legal educators must equip students with tools to reclaim legal conversations about freedom and equaltiy. The author, Dean Phoebe A. Haddon of the University of Maryland Francis King Carey School of Law, concludes with recollections of her late aunt, Rachel B. Noel, who played an instrumental part in the evolution of the Keyes case

Anisotropy of the Mobility of Pentacene from Frustration

The bandstructure of pentacene is calculated using first-principles density functional theory. A large anisotropy of the hole and electron effective masses within the molecular planes is found. The band dispersion of the HOMO and the LUMO is analyzed with the help of a tight-binding fit. The anisotropy is shown to be intimately related to the herringbone structure.Comment: Accepted for publication in Synthetic Metal

Electric-Field-Induced Mott Insulating States in Organic Field-Effect Transistors

We consider the possibility that the electrons injected into organic field-effect transistors are strongly correlated. A single layer of acenes can be modelled by a Hubbard Hamiltonian similar to that used for the kappa-(BEDT-TTF)(2)X family of organic superconductors. The injected electrons do not necessarily undergo a transition to a Mott insulator state as they would in bulk crystals when the system is half-filled. We calculate the fillings needed for obtaining insulating states in the framework of the slave-boson theory and in the limit of large Hubbard repulsion, U. We also suggest that these Mott states are unstable above some critical interlayer coupling or long-range Coulomb interaction.Comment: 9 pages, 7 figure

Magnetic Properties of Undoped C60C_{60}

The Heisenberg antiferromagnet, which arises from the large $U$ Hubbard model, is investigated on the $C_{60}$ molecule and other fullerenes. The connectivity of $C_{60}$ leads to an exotic classical ground state with nontrivial topology. We argue that there is no phase transition in the Hubbard model as a function of $U/t$, and thus the large $U$ solution is relevant for the physical case of intermediate coupling. The system undergoes a first order metamagnetic phase transition. We also consider the S=1/2 case using perturbation theory. Experimental tests are suggested.Comment: 12 pages, 3 figures (included

Single domain transport measurements of C60 films

Thin films of potassium doped C60, an organic semiconductor, have been grown on silicon. The films were grown in ultra-high vacuum by thermal evaporation of C60 onto oxide-terminated silicon as well as reconstructed Si(111). The substrate termination had a drastic influence on the C60 growth mode which is directly reflected in the electrical properties of the films. Measured on the single domain length scale, these films revealed resistivities comparable to bulk single crystals. In situ electrical transport properties were correlated to the morphology of the film determined by scanning tunneling microscopy. The observed excess conductivity above the superconducting transition can be attributed to two-dimensional fluctuations.Comment: 4 pages, 4 figure

Preparation and Properties of Nanocomposites from Pristine and Modified SWCNTs of Comparable Average Aspect Ratios

Low color, flexible, space-durable polyimide films with inherent and robust electrical conductivity to dissipate electrostatic charge (ESC) have been under investigation as part of a materials development activity for future NASA space missions. The use of single-walled carbon nanotubes (SWCNTs) is one means to achieving this goal. Even though the concentration of SWCNTs needed to achieve ESC dissipation is typically low, it is dependent upon purity, size, dispersion, and functionalization. In this study, SWCNTs prepared by the electric arc discharge method were used to synthesize nanocomposites using the LaRC(TradeMark) CP2 backbone as the matrix. Pristine and functionalized SWCNTs were mixed with an alkoxysilane terminated amide acid of LaRC(TradeMark) CP2 and the soluble imide form of the polymer and the resultant nanocomposites evaluated for mechanical, thermal, and electrical properties. Due to the preparative conditions for the pristine and functionalized SWCNTs, the average aspect ratio for both was comparable. This permitted the assessment of SWCNT functionalization with respect to various interactions (e.g. van der Waals, hydrogen bonding, covalent bond formation, etc.) with the matrix and the macroscopic effects upon nanocomposite properties. The results of this study are described herein

Formalism of collective electron excitations in fullerenes

We present a detailed formalism for the description of collective electron excitations in fullerenes in the process of the electron inelastic scattering. Considering the system as a spherical shell of a finite width, we show that the differential cross section is defined by three plasmon excitations, namely two coupled modes of the surface plasmon and the volume plasmon. The interplay of the three plasmons appears due to the electron diffraction of the fullerene shell. Plasmon modes of different angular momenta provide dominating contributions to the differential cross section depending on the transferred momentum.Comment: 11 pages, 2 figures; submitted to the special issue "Atomic Cluster Collisions: Structure and Dynamics from the Nuclear to the Biological Scale" of Eur. Phys. J.

Multiplex giant magnetoresistive biosensor microarrays identify interferon-associated autoantibodies in systemic lupus erythematosus.

High titer, class-switched autoantibodies are a hallmark of systemic lupus erythematosus (SLE). Dysregulation of the interferon (IFN) pathway is observed in individuals with active SLE, although the association of specific autoantibodies with chemokine score, a combined measurement of three IFN-regulated chemokines, is not known. To identify autoantibodies associated with chemokine score, we developed giant magnetoresistive (GMR) biosensor microarrays, which allow the parallel measurement of multiple serum antibodies to autoantigens and peptides. We used the microarrays to analyze serum samples from SLE patients and found individuals with high chemokine scores had significantly greater reactivity to 13 autoantigens than individuals with low chemokine scores. Our findings demonstrate that multiple autoantibodies, including antibodies to U1-70K and modified histone H2B tails, are associated with IFN dysregulation in SLE. Further, they show the microarrays are capable of identifying autoantibodies associated with relevant clinical manifestations of SLE, with potential for use as biomarkers in clinical practice