Methods for Detection and Correction of Sudden Pixel Sensitivity Drops

PDC 8.0 includes implementation of a new algorithm to detect and correct step discontinuities appearing in roughly one of every twenty stellar light curves during a given quarter. An example of such a discontinuity in an actual light curve is shown in fig. 1. The majority of such discontinuities are believed to result from high-energy particles (either cosmic or solar in origin) striking the photometer and causing permanent local changes (typically -0.5% in summed apertures) in quantum efficiency, though a partial exponential recovery is often observed. Since these features, dubbed sudden pixel sensitivity dropouts (SPSDs), are uncorrelated across targets they cannot be properly accounted for by the current detrending algorithm. PDC de-trending is based on the assumption that features in flux time series are due either to intrinsic stellar phenomena or to systematic errors and that systematics will exhibit measurable correlations across targets. SPSD events violate these assumptions and their successful removal not only rectifies the flux values of affected targets, but demonstrably improves the overall performance of PDC de-trending

Iron chlorosis in silver maple (Acer saccharum)

1978 Summer.Covers not scanned.Includes bibliographical references.Correctives for iron chlorosis have been applied to soil, sprayed on leaves and injected into woody plants. Some success in woody plants has been achieved from soil applied chelated Fe and injected Fe chelates. Silver maple has been unusual in that little response to chelated Fe was found. Experiments were devised to inject silver maples with different Fe chelate formulations, comparing results with a soil applied EDDHA treatment as well as chlorotic and green controls. Silver maple, for the most part, failed to respond to any of the chelate treatments applied. Foliar analyses revealed high levels of foliar Ca in chlorotic leaves compared to green leaves. When the soil producing green and chlorotic plants was analyzed, it was found that total soil Fe levels were higher for green control plants than chlorotic control plants. This increased level of total soil Fe was not reflected in the foliar analysis. There was no major distinction in foliar Fe levels between green and chlorotic tissue. Xylary sap pH and Eh were also recorded for silver maples growing in various solution cultures. Solution cultures were prepared to simulate various types of Fe stress capable of causing Fe chlorosis. Although the solution culture pH varied widely, xylary pH stayed relatively constant. Xylary Eh measurements maintained an even narrower "buffered" range. When pH and Eh were combined on a similar scale (pH+ pe), the xylary sap pe + pH was observed to stay in a narrow range even when solution pe + pH varied widely

A Look at Public Health

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Inspiring Vision and Practice: CultureWork, a leading voice for arts and cultural management praxis

3 pagesIn this issue of CultureWork we take a moment to look back and reflect on the publication’s past. As part of this reflection we celebrate the legacy and history of arts management practice upon which we have focused. Over its 15 years of publication, CultureWork has consistently shared relevant, timely work from within the field of arts and cultural management, including emerging research and practical advisories

Regional Archives in the People\u27s Republic of China: A Case Study of the Chongqing Municipal Archives and the Yunnan Provincial Archives

The emergence of China as an active member of the international community and the growing number of exchange programs between archival institutions in China and the United States have fostered broader professional contacts between American archivists and their counterparts in China. Consequently, American archivists have become increasingly curious about the professional practices of their Chinese colleagues. The following description and analysis offers a case study of the structure, function, and use of Chinese regional archives

Iron mineralogy of a Hawaiian palagonitic soil with Mars-like spectral and magnetic properties

Visible and near-IR spectral data for some palagonitic soils from Mauna Kea, Hawaii, are similar to corresponding spectral data for Mars. It is important to understand the composition, distribution, and mineralogy of the ferric-bearing phases for the best spectral analogues because the correspondence in spectral properties implies that the nature of their ferric-bearing phases may be similar to those on Mars. In order to constrain interpretations of the Martian data, a variety of palagonitic soils should be studied in order to establish to what extent differences in their spectral data correspond to differences in the mineralogy of their ferric-bearing phases. Spectral (350-2100 nm), Mossbauer, magnetic, and some compositional data for one of a suite of Hawaiian palagonitic soils are presented. The soil (HWMK1) was collected below the biologically active zone from the sides of a gully cut at 9000 ft elevation on Mauna Kea. The soil was wet sieved with freon into seven size fractions less than 1 mm

What Happened with No-Till in 1988

No-till (NT) received some bad publicity in 1988 in Kentucky and throughout the Midwest,especially during the early part of last summer\u27s drought. Some farmers found that corn yields were lower with NT than with conventional tillage (CT). However, others observed that the NT corn recovered faster and grew better than CT corn following the rains. Data from Kentucky and Nebraska tend to support this latter observation