Soils of Day County South Dakota

The soil map, in the folder attached to the back cover of this bulletin, has been divided into two sections, the eastern half and the western half. These maps show the distribution of different soils that occur in the county. In the text, recommendations as to the use, management, and conservation are made in an attempt to answer the major questions of the farmers and others interested in the soils of Day County

Transcriptome profiling reveals expression signatures of cranial neural crest cells arising from different axial levels

Background: Cranial neural crest cells (NCCs) are a unique embryonic cell type which give rise to a diverse array of derivatives extending from neurons and glia through to bone and cartilage. Depending on their point of origin along the antero-posterior axis cranial NCCs are rapidly sorted into distinct migratory streams that give rise to axial specific structures. These migratory streams mirror the underlying segmentation of the brain with NCCs exiting the diencephalon and midbrain following distinct paths compared to those exiting the hindbrain rhombomeres (r). The genetic landscape of cranial NCCs arising at different axial levels remains unknown. Results: Here we have used RNA sequencing to uncover the transcriptional profiles of mouse cranial NCCs arising at different axial levels. Whole transcriptome analysis identified over 120 transcripts differentially expressed between NCCs arising anterior to r3 (referred to as r1-r2 migratory stream for simplicity) and the r4 migratory stream. Eight of the genes differentially expressed between these populations were validated by RT-PCR with 2 being further validated by in situ hybridisation. We also explored the expression of the Neuropilins (Nrp1 and Nrp2) and their co-receptors and show that the A-type Plexins are differentially expressed in different cranial NCC streams. Conclusions: Our analyses identify a large number of genes differentially regulated between cranial NCCs arising at different axial levels. This data provides a comprehensive description of the genetic landscape driving diversity of distinct cranial NCC streams and provides novel insight into the regulatory networks controlling the formation of specific skeletal elements and the mechanisms promoting migration along different paths.Rachael Lumb, Sam Buckberry, Genevieve Secker, David Lawrence and Quenten Schwar

UV observations of the galaxy cluster Abell 1795 with the optical monitor on XMM-Newton

We present the results of an analysis of broad band UV observations of the central regions of Abell 1795 observed with the optical monitor on XMM-Newton. As have been found with other UV observations of the central regions of clusters of galaxies, we find evidence for star formation. However, we also find evidence for absorption in the cD galaxy on a more extended scale than has been seen with optical imaging. We also report the first UV observation of part of the filamentary structure seen in H$\alpha$, X-rays and very deep U band imaging. The part of the filament we see is very blue with UV colours consistent with a very early (O/B) stellar population. This is the first direct evidence of a dominant population of early type stars at the centre of Abell 1795 and implies very recent star formation at the centre of this clusterComment: 6 pages, 3 figures accepted by A&A Letter

Simulating CCDs for the Chandra Advanced CCD Imaging Spectrometer

We have implemented a Monte Carlo algorithm to model and predict the response of various kinds of CCDs to X-ray photons and minimally-ionizing particles and have applied this model to the CCDs in the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer. This algorithm draws on empirical results and predicts the response of all basic types of X-ray CCD devices. It relies on new solutions of the diffusion equation, including recombination, to predict the radial charge cloud distribution in field-free regions of CCDs. By adjusting the size of the charge clouds, we can reproduce the event grade distribution seen in calibration data. Using a model of the channel stops developed here and an insightful treatment of the insulating layer under the gate structure developed at MIT, we are able to reproduce all notable features in ACIS calibration spectra. The simulator is used to reproduce ground and flight calibration data from ACIS, thus confirming its fidelity. It can then be used for a variety of calibration tasks, such as generating spectral response matrices for spectral fitting of astrophysical sources, quantum efficiency estimation, and modeling of photon pile-up.Comment: 42 pages, 22 figures; accepted for publication in Nuclear Instruments and Methods in Physics Research, Section A; paper with high-quality figures can be found at ftp://ftp.astro.psu.edu/pub/townsley/simulator.p

X-ray Spectroscopy of the Cluster of Galaxies Abell 1795 with XMM-Newton

The initial results from XMM-Newton observations of the rich cluster of galaxies Abell 1795 are presented. The spatially-resolved X-ray spectra taken by the European Photon Imaging Cameras (EPIC) show a temperature drop at a radius of $\sim 200$ kpc from the cluster center, indicating that the ICM is cooling. Both the EPIC and the Reflection Grating Spectrometers (RGS) spectra extracted from the cluster center can be described by an isothermal model with a temperature of $\sim 4$ keV. The volume emission measure of any cool component ($<1$ keV) is less than a few % of the hot component at the cluster center. A strong OVIII Lyman-alpha line was detected with the RGS from the cluster core. The O abundance and its ratio to Fe at the cluster center is 0.2--0.5 and 0.5--1.5 times the solar value, respectively.Comment: Accepted: A&A Letters, 2001, 6 page

Nietzschean modes of gender construction in a post-feminist age

An arrogance of certainty besets discourses of gender in today’s culture, and denigrating as well as overly affirming accounts of masculinity leave theindividual man at risk of either self-loathing or self-aggrandizing. This article will look at various lay accounts of masculinity and the dynamics of itsconstruction in opposition to culturally dominant moral codes, and will interrogate the underlying philosophical positions at work through Nietzsche’s Genealogy of Morality. In doing so, we propose that it is helpful to see Nietzsche as an early philosopher of difference, and embrace a less fixed approach to ontologies of gender accordingly

XMM-Newton discovery of an X-ray filament in Coma

XMM-Newton observations of the outskirts of the Coma cluster of galaxies confirm the existence of a soft X-ray excess claimed previously and show it comes from warm thermal emission. Our data provide a robust estimate of its temperature (~0.2 keV) and oxygen abundance (~0.1 solar). Using a combination of XMM-Newton and ROSAT All-Sky Survey data, we rule out a Galactic origin of the soft X-ray emission. Associating this emission with a 20 Mpc region in front of Coma, seen in the skewness of its galaxy velocity distribution, yields an estimate of the density of the warm gas of ~50 f_baryon rho_critical, where f_baryon is the baryon fraction of the gas and rho_critical is the critical density needed to halt the expansion of the universe. Our measurement of the gas mass associated with the warm emission strongly support its nonvirialized nature, suggesting that we are observing the warm-hot intergalactic medium (WHIM). Our measurements provide a direct estimate of the O, Ne and Fe abundance of the WHIM. Differences with the reported Ne/O ratio for some OVI absorbers hints at a different origin of the OVI absorbers and the Coma filament. We argue that the Coma filament has likely been preheated, but at a substantially lower level compared to what is seen in the outskirts of groups. The thermodynamic state of the gas in the Coma filament reduces the star-formation rate in the embedded spiral galaxies, providing an explanation for the presence of passive spirals observed in this and other clusters.Comment: 9 pages, 5 figures, accepted by A&

X-ray Sources in the Hubble Deep Field Detected by Chandra

We present first results from an X-ray study of the Hubble Deep Field North (HDF-N) and its environs obtained using 166 ks of data collected by the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-ray Observatory. This is the deepest X-ray observation ever reported, and in the HDF-N itself we detect six X-ray sources down to a 0.5--8 keV flux limit of 4E-16 erg cm^-2 s^-1. Comparing these sources with objects seen in multiwavelength HDF-N studies shows positional coincidences with the extremely red object NICMOS J123651.74 +621221.4, an active galactic nucleus (AGN), three elliptical galaxies, and one nearby spiral galaxy. The X-ray emission from the ellipticals is consistent with that expected from a hot interstellar medium, and the spiral galaxy emission may arise from a `super-Eddington' X-ray binary or ultraluminous supernova remnant. Four of the X-ray sources have been detected at radio wavelengths. We also place X-ray upper limits on AGN candidates found in the HDF-N, and we present the tightest constraints yet on X-ray emission from the SCUBA submillimeter source population. None of the 10 high-significance submillimeter sources reported in the HDF-N and its vicinity is detected with Chandra ACIS. These sources appear to be dominated by star formation or have AGN with Compton-thick tori and little circumnuclear X-ray scattering.Comment: 11 pages, ApJ, in press, also available from http://www.astro.psu.edu/users/niel/hdf/hdf-chandra.htm