Jack Hopkins\u27 Civil War

In the 1862 Pennsylvania College album there is a photograph of John Hopkins, who that year was entering his fifteenth year of service as the college\u27s janitor. In one student\u27s book, the portrait of Hopkins jokingly refers to him as the school\u27s vice president. This appellation speaks volumes about the life of the African-American custodian, for while it was clearly made in jest as a token of the students\u27 genuine affection for Hopkins, it symbolizes the gulf between the white students and the black janitor. It goes without saying that the students found the picture humorous because they understood that in their time, a black man could never be the vice president. John Hopkins was born in Maryland in 1806. The 1860 census lists him as a mulatto. Very little else is known about Hopkins\u27s first forty-one years. Was he born free or a slave? Did he leave Maryland openly, or escape via the Underground Railroad? All that is known for certain is that Hopkins was in Pennsylvania by 1841 or early 1842. Unfortunately, large gaps like these are fairly typical when researching Pennsylvania\u27s antebellum African Americans. [excerpt

Book Review: Thaddeus Stevens in Gettysburg: The Making of an Abolitionist

Over a million and a half tourists visit Gettysburg every year, finding the quintessence of American history in the borough and surrounding battlefields. Had the great battle been fought elsewhere, it is likely that Gettysburg\u27s legacy in American history would instead be the town where Thaddeus Stevens spent the formative years of his legal practice and political career. As the subtitle to Dr. Bradley R. Roch\u27s new book, Thaddeus Stevens in Gettysburg: The Making of an Abolitionist, makes abundantly clear, it is also the town where the man often put forward as the most radical of Radical Republicans formulated his views on slavery and race relations. For this alone Dr. Roch\u27s work is an important contribution for those looking for an understanding of the Civil War era. But the first fifty years of Stevens\u27 life - the period covered in depth in this book - presents a microcosm of the time, including a rough and tumble litigious society, splinter political factions, challenges to duels, and the last remnants of frontier-style violence. For this, Dr. Roch\u27s book is worthy of a larger audience. [excerpt

Potential competitive effects on U.S. bank credit card lending from the proposed bifurcated application of Basel II

This paper analyzes the potential competitive effects of the proposed bifurcated application of Basel II capital regulations in the United States on bank credit card lending activities. For this purpose, the authors consider the Basel II regulations as stated in the June 2004 Basel Committee Framework Agreement. ; Also issued as Payment Cards Center Discussion Paper No. 05-21 ; Superseded by Working Paper 07-09Basel capital accord ; Credit cards

Feshbach resonance of heavy exciton-polaritons

We study interactions between polaritons formed by hybridization of excitons in a two-dimensional (2D) semiconductor with surface optical phonons or plasmons. These quasiparticles have a high effective mass and can bind into bipolaritons near a Feshbach-like scattering resonance. We analyze the phase diagram of a many-body condensate of heavy polaritons and bipolaritons and calculate their absorption and luminescence spectra, which can be measured experimentally.Comment: 11 pages, 7 figure

Rotational Viscometry of a Zinc Phosphate and a Zinc Polyacrylate Cement

The rheological properties of a zinc phosphate and a zinc polyacrylate cement were investigated using a rotational viscometer. The effects of time, temperature, shear rate, and spindle geometry on the measured viscosities were evaluated. Results indicated that both cements exhibited Newtonian behavior.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66697/2/10.1177_00220345770560071001.pd

Transcription-Independent Heritability of Induced Histone Modifications in the Mouse Preimplantation Embryo

Enzyme-catalyzed, post-translational modifications of core histones have been implicated in the complex changes in gene expression that drive early mammalian development. However, until recently the small number of cells available from the preimplantation embryo itself has prevented quantitative analysis of histone modifications at key regulator genes. The possible involvement of histone modifications in the embryo's response to extracellular signals, or as determinants of cell fate or lineage progression, remains unclear. Here we describe the use of a recently-developed chromatin immunoprecipitation technique (CChIP) to assay histone modification levels at key regulator genes (Pou5f1, Nanog, Cdx2, Hoxb1, Hoxb9) as mouse embryos progress from 8-cell to blastocyst in culture. Only by the blastocyst stage, when the embryonic (Inner Cell Mass) and extra-embryonic (Trophoblast) lineages are compared, do we see the expected association between histone modifications previously linked to active and silent chromatin, and transcriptional state. To explore responses to an environmental signal, we exposed embryos to the histone deacetylase inhibitor, anti-epileptic and known teratogen valproic acid (VPA), during progression from 8-cell to morula stage. Such treatment increased H4 acetylation and H3 lysine 4 methylation at the promoters of Hoxb1 and Hoxb9, but not the promoters of Pou5f1, Nanog,Cdx2 or the housekeeping gene Gapdh. Despite the absence of detectable Hoxb transcription, these VPA-induced changes were heritable, following removal of the inhibitor, at least until the blastocyst stage. The selective hyperacetylation of Hoxb promoters in response to a histone deacetylase inhibitor, suggests that Hox genes have a higher turnover of histone acetates than other genes in the preimplantation embryo. To explain the heritability, through mitosis, of VPA-induced changes in histone modification at Hoxb promoters, we describe how an epigenetic feed-forward loop, based on cross-talk between H3 acetylation and H3K4 methylation, might generate a persistently increased steady-state level of histone acetylation in response to a transient signal

Local Structure and Bonding of Carbon Nanothreads Probed by High-Resolution Transmission Electron Microscopy

Carbon nanothreads are a new one-dimensional sp^3-bonded nanomaterial of CH stoichiometry synthesized from benzene at high pressure and room temperature by slow solid-state polymerization. The resulting threads assume crystalline packing hundreds of micrometers across. We show high-resolution electron microscopy (HREM) images of hexagonal arrays of well-aligned thread columns that traverse the 80–100 nm thickness of the prepared sample. Diffuse scattering in electron diffraction reveals that nanothreads are packed with axial and/or azimuthal disregistry between them. Layer lines in diffraction from annealed nanothreads provide the first evidence of translational order along their length, indicating that this solid-state reaction proceeds with some regularity. HREM also reveals bends and defects in nanothread crystals that can contribute to the broadening of their diffraction spots, and electron energy-loss spectroscopy confirms them to be primarily sp^3-hybridized, with less than 27% sp^2 carbon, most likely associated with partially saturated “degree-4” threads