A history of public education in the City of Sacramento : with special emphasis upon the administration of Charles C. Hughes beginning in 1913

The influx of people into Sacramento during the days of the Gold Rush brought many problems to the citizens of this new community. One problem that manifested itself early was that of educating the children of the pioneer population

Conjugation of injections by permutations

Let X be a countably infinite set, and let f, g, and h be any three injective self-maps of X, each having at least one infinite cycle. (For instance, this holds if f, g, and h are not bijections.) We show that there are permutations a and b of X such that h=afa^{-1}bgb^{-1} if and only if |X\Xf|+|X\Xg|=|X\Xh|. We also prove a version of this statement that holds for infinite sets X that are not necessarily countable. This generalizes results of Droste and Ore about permutations.Comment: 27 pages, 4 figure

Comment on "Correlation between Compact Radio Lout Quasars and Ultrahigh Energy Cosmic Rays"

In a recent paper, Farrar and Biermann argue that there is a strong correlation between the direction of the five highest-energy cosmic-ray events and compact, radio-loud quasars. This Comment shows that this analysis contains several inconsistencies and errors so that the significance of any such correlation is certainly greatly overestimated and perhaps nonexistent.Comment: 2 pages, REVTE

Lightning in the eastern Alps 1993-1999, part I: Thunderstorm tracks

International audienceThunderstorm tracks in the eastern Alps for the summers of 1993-1999 are investigated based on lightning data. The tracking method consists of three steps. Step one filters weak storms. Step two fixes the positions of the single cells, which are then connected. The wind at 700hPa, which approximates the steering level of the thunderstorms, is used to distinguish between six weather patterns. Maps including all discovered tracks are discussed for each flow type. While locations from which thunderstorms originate are almost similar, the track patterns are distinct for each flow type. Main initiation areas are mountain ranges of moderate altitude (?2.5km MSL) from where most of the tracks lead into flat areas

Preparation of Mammalian Skeletons

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Activation-induced deoxycytidine deaminase (AID) co-transcriptional scanning at single-molecule resolution

Activation-induced deoxycytidine deaminase (AID) generates antibody diversity in B cells by initiating somatic hypermutation (SHM) and class-switch recombination (CSR) during transcription of immunoglobulin variable (IgV) and switch region (IgS) DNA. Using single-molecule FRET, we show that AID binds to transcribed dsDNA and translocates unidirectionally in concert with RNA polymerase (RNAP) on moving transcription bubbles, while increasing the fraction of stalled bubbles. AID scans randomly when constrained in an 8 nt model bubble. When unconstrained on single-stranded (ss) DNA, AID moves in random bidirectional short slides/hops over the entire molecule while remaining bound for ~5 min. Our analysis distinguishes dynamic scanning from static ssDNA creasing. That AID alone can track along with RNAP during transcription and scan within stalled transcription bubbles suggests a mechanism by which AID can initiate SHM and CSR when properly regulated, yet when unregulated can access non-Ig genes and cause cancer