PC1643+4631A,B: The Lyman-Alpha Forest at the Edge of Coherence

This is the first measurement and detection of coherence in the intergalactic medium (IGM) at substantially high redshift (z~3.8) and on large physical scales (~2.5 h^-1 Mpc). We perform the measurement by presenting new observations from Keck LRIS of the high redshift quasar pair PC 1643+4631A, B and their Ly-alpha absorber coincidences. This experiment extends multiple sightline quasar absorber studies to higher redshift, higher opacity, larger transverse separation, and into a regime where coherence across the IGM becomes weak and difficult to detect. We fit 222 discrete Ly-alpha absorbers to sightline A and 211 to sightline B. Relative to a Monte Carlo pairing test (using symmetric, nearest neighbor matching) the data exhibit a 4sigma excess of pairs at low velocity splitting (<150 km/s), thus detecting coherence on transverse scales of ~2.5 h^-1 Mpc. We use spectra extracted from an SPH simulation to analyze symmetric pair matching, transmission distributions as a function of redshift and compute zero-lag cross-correlations to compare with the quasar pair data. The simulations agree with the data with the same strength (~4sigma) at similarly low velocity splitting above random chance pairings. In cross-correlation tests, the simulations agree when the mean flux (as a function of redshift) is assumed to follow the prescription given by Kirkman et al. (2005). While the detection of flux correlation (measured through coincident absorbers and cross-correlation amplitude) is only marginally significant, the agreement between data and simulations is encouraging for future work in which even better quality data will provide the best insight into the overarching structure of the IGM and its understanding as shown by SPH simulations.Comment: 15 pages, 11 figures; accepted for publication in Astronomical Journa

Observations on the Staining of Bacterial Flagella

Influence of the pH of the medium, on the staining of flagella, as shown by several of the more highly recommended methods

A New Reservation Area in Iowa

Adjoining the city of McGregor on the west, an area of about twenty acres, called the Iowa Memorial Arboretum is projected. This is to be restocked, where needed, with native species, and certain hardy exotics are also to be introduced. Other attractions, including a museum, are projected

The Biota of the Cedar River as Related to Odor and Taste Production

This paper presents a brief summary of surveys carried through the past two years, as an aid in the control of odor and taste in city water. So far as the writer is aware, no work of this kind has previously been done at Cedar Rapids, hence comparisons can only be drawn between the years covered, or amongst the months represented

Master of Its Own Case: EEOC Investigations after Issuing a Right-to-sue Notice

The Equal Employment Opportunity Commission (EEOC) is responsible for enforcing the full arsenal of federal employment discrimination laws. But in addition to vindicating the rights of employment discrimination victims, the EEOC also serves as a gatekeeper to screen claims before they get to court. As part of that gatekeeping function, Congress requires that individuals alleging employment discrimination under Title VII of the Civil Rights Act of 1964 must obtain permission from the EEOC before they can bring legal action on their own. Title VII’s text leaves the EEOC’s role after issuing a right-to-sue notice ambiguous. Despite this ambiguity, or perhaps because of it, the EEOC promulgated 29 CFR § 1601.28(a)(3), which interprets Title VII as allowing the agency to continue its investigation when it would further the broad antidiscrimination mission Congress tasked it to carry out. The EEOC typically terminates its investigation after it issues a right-to-sue notice. But the times it has continued to investigate, the EEOC often has faced litigation challenging its statutory authority to do so. The circuit courts to confront the ambiguity regarding the EEOC’s authority in this context have come to conflicting results. On one side, the Fifth Circuit has held that the issuance of a right-to-sue notice strips the EEOC of its authority to investigate. On the other, the Seventh and Ninth Circuits have held that the EEOC not only retains its authority to investigate employment discrimination claims after issuing a right-to-sue notice, but that continued investigations promote the broad purposes of Title VII. This Comment addresses this unresolved question through the lens of judicial deference to administrative agencies, a doctrine that the circuit courts largely have ignored. Applying the two-step analysis from Chevron, this Comment first argues that the text of Title VII is ambiguous and that Congress intended to give the agency the authority to interpret the statute’s procedural provisions. It then argues that § 1601.28(a)(3) is both procedural and a reasonable interpretation of Title VII and that, therefore, the EEOC’s interpretation is entitled to Chevron deferenc

Weeds and Their Control

The aim of this bulletin has been to include only the worst weeds which are more or less general throughout the state, but the writer has also added other facts of interest and value about weeds. The successful man or woman of today must know a great deal more than formerly about his or her occupation and about good living if more profit and enjoyment are to be obtained from life. This bulletin contains more than a mere set of directions, by which one may come to know and destroy some weeds. How weeds destroy the value of labor, of crops, of livestock, of farms, and of human health, are explained by the author who has had many years of experience as a farmer, teacher, and investigator. It is hoped that those having special weed problems which are not included will be led to further study of the books and other sources mentioned at the end of the bulletin, and to further inquiry directed to the Experiment Station specialists

Additions to the Flora of Linn County

A list of unreported species for Linn County, Iowa, together with remarks upon emendations

Feeder Cattle Hedge Lifting Strategies for North Dakota

Marketing,

Comparing Simulations and Observations of the Lyman-Alpha Forest I. Methodology

We describe techniques for comparing spectra extracted from cosmological simulations and observational data, using the same methodology to link Lyman-alpha properties derived from the simulations with properties derived from observational data. The eventual goal is to measure the coherence or clustering properties of Lyman-alpha absorbers using observations of quasar pairs and groups. We quantify the systematic underestimate in opacity that is inherent in the continuum fitting process of observed spectra over a range of resolution and signal-to-noise ratio. We present an automated process for detecting and selecting absorption features over the range of resolution and signal-to-noise of typical observational data on the Lyman-alpha "forest". Using these techniques, we detect coherence over transverse scales out to 500 h^{-1}_{50} kpc in spectra extracted from a cosmological simulation at z = 2.Comment: 52 pages, includes 14 figures, to appear in ApJ v566 Feb 200