1,164 research outputs found

    The integrated planning method of project planning, development and implementation

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    Present comprehensive planning endeavors lack a consistent methodology which will produce realistic, useable results. The validity of this statement should be obvious after one has read Miller\u27s Evaluation of City and Region Planning Techniques. This paper contains a methodology, The Integrated Planning Method, which will go a long way toward correcting this gross inadequacy that planners presently encounter in directing planning efforts. Two government developed planning and analysis procedures that, up until this time have been applied almost exclusively to hardware systems, have been combined into one integrated planning methodology that will provide not only meaningful and rigorous definition and analysis of any problem faced by the planner but a path to a solution that, if followed, will produce a complete system for planning and implementation. Analysis of existing plans, planning methodologies and planning problems is to be the suggested use of the Value Analysis procedure that up to the present has only been used by the Department of Defense and industrial organizations to improve hardware systems. Phase Project Planning as developed by the National Aerounatics and Space Administration for use in planning for space hardware systems and their supporting personnel and equipment will be the suggested method for developing the desired plans. Each, in the past has been utilized separately. This report lays out a method of combining them into an Integrated Planning Method which will be applicable to all planning efforts --Abstract, pages ii-iii

    The Murchison Widefield Array: Design Overview

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    The Murchison Widefield Array (MWA) is a dipole-based aperture array synthesis telescope designed to operate in the 80-300 MHz frequency range. It is capable of a wide range of science investigations, but is initially focused on three key science projects. These are detection and characterization of 3-dimensional brightness temperature fluctuations in the 21cm line of neutral hydrogen during the Epoch of Reionization (EoR) at redshifts from 6 to 10, solar imaging and remote sensing of the inner heliosphere via propagation effects on signals from distant background sources,and high-sensitivity exploration of the variable radio sky. The array design features 8192 dual-polarization broad-band active dipoles, arranged into 512 tiles comprising 16 dipoles each. The tiles are quasi-randomly distributed over an aperture 1.5km in diameter, with a small number of outliers extending to 3km. All tile-tile baselines are correlated in custom FPGA-based hardware, yielding a Nyquist-sampled instantaneous monochromatic uv coverage and unprecedented point spread function (PSF) quality. The correlated data are calibrated in real time using novel position-dependent self-calibration algorithms. The array is located in the Murchison region of outback Western Australia. This region is characterized by extremely low population density and a superbly radio-quiet environment,allowing full exploitation of the instrumental capabilities.Comment: 9 pages, 5 figures, 1 table. Accepted for publication in Proceedings of the IEE

    Children\u27s experiences of companion animal maltreatment in households characterized by intimate partner violence

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    Cruelty toward companion animals is a well-documented, coercive tactic used by abusive partners to intimidate and control their intimate partners. Experiences of co-occurring violence are common for children living in families with intimate partner violence (IPV) and surveys show that more than half are also exposed to abuse of their pets. Given children\u27s relationships with their pets, witnessing such abuse may be traumatic for them. Yet little is known about the prevalence and significance of this issue for children. The present study examines the experiences of children in families with co-occurring pet abuse and IPV. Using qualitative methods, 58 children ages 7–12 who were exposed to IPV were asked to describe their experiences of threats to and harm of their companion animals. Following the interviews, template analysis was employed to systematically develop codes and themes. Coding reliability was assessed using Randolph\u27s free-marginal multirater kappa (kfree = .90). Five themes emerged from the qualitative data, the most common being children\u27s exposure to pet abuse as a power and control tactic against their mother in the context of IPV. Other themes were animal maltreatment to discipline or punish the pet, animal cruelty by a sibling, children intervening to prevent pet abuse, and children intervening to protect the pet during a violent episode. Results indicate that children\u27s experiences of pet abuse are multifaceted, potentially traumatic, and may involve multiple family members with diverse motives

    A Multidisciplinary Investigation of a Polycythemia Vera Cancer Cluster of Unknown Origin

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    Cancer cluster investigations rarely receive significant public health resource allocations due to numerous inherent challenges and the limited success of past efforts. In 2008, a cluster of polycythemia vera, a rare blood cancer with unknown etiology, was identified in northeast Pennsylvania. A multidisciplinary group of federal and state agencies, academic institutions, and local healthcare providers subsequently developed a multifaceted research portfolio designed to better understand the cause of the cluster. This research agenda represents a unique and important opportunity to demonstrate that cancer cluster investigations can produce desirable public health and scientific outcomes when necessary resources are available

    Field Deployment of Prototype Antenna Tiles for the Mileura Widefield Array--Low Frequency Demonstrator

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    Experiments were performed with prototype antenna tiles for the Mileura Widefield Array--Low Frequency Demonstrator (MWA-LFD) to better understand the widefield, wideband properties of their design and to characterize the radio frequency interference (RFI) between 80 and 300 MHz at the site in Western Australia. Observations acquired during the six month deployment confirmed the predicted sensitivity of the antennas, sky-noise dominated system temperatures, and phase-coherent interferometric measurements. The radio spectrum is remarkably free of strong terrestrial signals, with the exception of two narrow frequency bands allocated to satellite downlinks and rare bursts due to ground-based transmissions being scattered from aircraft and meteor trails. Results indicate the potential of the MWA-LFD to make significant achievements in its three key science objectives: epoch of reionziation science, heliospheric science, and radio transient detection.Comment: Accepted by AJ. 17 pages with figure

    Variability of Disk Emission in Pre-Main Sequence and Related Stars. II. Variability in the Gas and Dust Emission of the Herbig Fe Star SAO 206462

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    We present thirteen epochs of near-infrared (0.8-5 micron) spectroscopic observations of the pre-transitional, "gapped" disk system in SAO 206462 (=HD 135344B). In all, six gas emission lines (including Br gamma, Pa beta, and the 0.8446 micron line of O I) along with continuum measurements made near the standard J, H, K, and L photometric bands were measured. A mass accretion rate of approximately 2 x 10^-8 solar masses per year was derived from the Br gamma and Pa beta lines. However, the fluxes of these lines varied by a factor of over two during the course of a few months. The continuum also varied, but by only ~30%, and even decreased at a time when the gas emission was increasing. The H I line at 1.083 microns was also found to vary in a manner inconsistent with that of either the hydrogen lines or the dust. Both the gas and dust variabilities indicate significant changes in the region of the inner gas and the inner dust belt that may be common to many young disk systems. If planets are responsible for defining the inner edge of the gap, they could interact with the material on time scales commensurate with what is observed for the variations in the dust, while other disk instabilities (thermal, magnetorotational) would operate there on longer time scales than we observe for the inner dust belt. For SAO 206462, the orbital period would likely be 1-3 years. If the changes are being induced in the disk material closer to the star than the gap, a variety of mechanisms (disk instabilities, interactions via planets) might be responsible for the changes seen. The He I feature is most likely due to a wind whose orientation changes with respect to the observer on time scales of a day or less. To further constrain the origin of the gas and dust emission will require multiple spectroscopic and interferometric observations on both shorter and longer time scales that have been sampled so far.Comment: 42 pages, 10 figure

    First spectroscopic imaging observations of the sun at low radio frequencies with the Murchison Widefield Array Prototype

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    We present the first spectroscopic images of solar radio transients from the prototype for the Murchison Widefield Array, observed on 2010 March 27. Our observations span the instantaneous frequency band 170.9- 201.6 MHz. Though our observing period is characterized as a period of "low" to "medium" activity, one broadband emission feature and numerous short-lived, narrowband, non-thermal emission features are evident. Our data represent a significant advance in low radio frequency solar imaging, enabling us to follow the spatial, spectral, and temporal evolution of events simultaneously and in unprecedented detail. The rich variety of features seen here reaffirms the coronal diagnostic capability of low radio frequency emission and provides an early glimpse of the nature of radio observations that will become available as the next generation of low-frequency radio interferometers come online over the next few years

    The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies

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    The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80–300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3-km diameter area. Novel hybrid hardware/software correlation and a real-time imaging and calibration systems comprise the MWA signal processing backend. In this paper, the as-built MWA is described both at a system and sub-system level, the expected performance of the array is presented, and the science goals of the instrument are summarised
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