231 research outputs found

    Provider Perspectives on Mississippi\u27s Child Care Payment Program

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    The Mississippi Child Care Payment Program allocates public dollars from the Child Care Development Block Grant to decrease the cost of child care to qualifying Mississippi families. The purpose of this research is to examine how the coronavirus pandemic and ensuing policy changes from the state of Mississippi shaped child care providers\u27 experience with the Child Care Payment Program. By surveying child care providers, this researcher assesses to analyze the effectiveness of the program and determines remaining what areas of need. Please note that this research applies to policies prior to the 2023 revision to the Child Care Payment Program handbook

    Imaginative methods: a feminist rereading of John Maynard Keynes

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    This thesis uses a feminist lens to reveal aspects of the life of John Maynard Keynes that previous scholarship has missed. lt uses a feminist framework to view the connections between Keynes\u27s lived experiences, beliefs, and work in a fuller and more nuanced way. The research highlights the importance of Keynes\u27s sexuality, his connection to women and women\u27s issues, and the significance of his relationships to friends, family, lovers, and colleagues. Feminist theory questions objectivity in knowledge production, argues for the importance of lived experience, and requires us to grapple with interconnected identities, which leads to a new interpretation of Keynes\u27s life. His life becomes a historically situated project where every event had a personal and professional impact

    High Galactic latitude polarized emission at 1.4 GHz and implications for cosmic microwave background observations

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    We analyse the polarized emission at 1.4 GHz in a 3x3 deg^2 area at high Galactic latitude (b ~ -40deg). The region, centred in (RA=5h, Dec=-49deg), was observed with the Australia Telescope Compact Array radio-interferometer, whose 3-30 arcmin angular sensitivity range allows the study of scales appropriate for CMB Polarization (CMBP) investigations. The angular behavior of the diffuse emission is analysed through the E- and B-mode power spectra. These follow a power law ClXlβXC^X_l \propto l^{\beta_X} with slopes \beta_E = -1.97 \pm 0.08 and \beta_B = -1.98 \pm 0.07. The emission is found to be about a factor 25 fainter than in Galactic plane regions. The comparison of the power spectra with other surveys indicates that this area is intermediate between strong and negligible Faraday rotation effects. A similar conclusion can be reached by analysing both the frequency and Galactic latitude behaviors of the diffuse Galactic emission of the 408-1411 MHz Leiden survey data. We present an analysis of the Faraday rotation effects on the polarized power spectra, and find that the observed power spectra can be enhanced by a transfer of power from large to small angular scales. The extrapolation of the spectra to 32 and 90GHz of the CMB window suggests that Galactic synchrotron emission leaves the CMBP E-mode uncontaminated at 32GHz. The level of the contamination at 90GHz is expected to be more than 4 orders of magnitude below the CMBP spectrum. Extrapolating to the relevant angular scales, this region also appears adequate for investigation of the CMBP B-modes for models with tensor/scalar fluctuation power ratio T/S>0.01. We also identify polarized point sources in the field, providing a 9 object list which is complete down to the polarized flux limit of S^p_lim = 2 mJy.Comment: 13 pages, 11 figures, accepted for publication in MNRA

    Faraday Rotation as a Diagnostic of Galactic Foreground Contamination of CMB Maps

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    We present a diagnostic test of possible Galactic contamination of cosmic microwave background sky maps designed to provide an independent check on the methods used to compile these maps. The method involves a non-parametric measurement of cross-correlation between the Faraday rotation measure (RM) of extragalactic sources and the measured microwave signal at the same angular position. We argue that statistical properties of the observed distribution of rotation measures are consistent with a Galactic origin, an argument reinforced by a direct measurement of cross-correlation between dust, free-free and synchrotron foreground maps and RM values with the strongest correlation being for dust and free-free. We do not find any statistically compelling evidence for correlations between the RM values and the COBE DMR maps at any frequency, so there is no evidence of residual contamination in these CMB maps. On the other hand, there is a statistically significant correlation of RM with the preliminary WMAP individual frequency maps which remains significant in the Tegmark et al. Wiener-filtered map but not in the Internal Linear Combination map produced by the WMAP team.Comment: 8 pages, 1 figure, accepted for publication in MNRA

    Terrain Awareness Using a Tracked Skid-Steering Vehicle With Passive Independent Suspensions

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    This paper presents a novel approach for terrain characterization based on a tracked skid-steer vehicle with a passive independent suspensions system. A set of physics-based parameters is used to characterize the terrain properties: drive motor electrical currents, the equivalent track, the power spectral density for the vertical accelerations and motor currents. Based on this feature set, the system predicts the type of terrain that the robot traverses. A wide set of experimental results acquired on various surfaces are provided to verify the study in the field, proving its effectiveness for application in autonomous robots

    High-resolution radio continuum survey of M33: III. Magnetic fields

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    Using the linearly polarized intensity and polarization angle data at 3.6, 6.2 and 20 cm, we determine variations of Faraday rotation and depolarization across the nearby galaxy M33. A 3-D model of the regular magnetic field is fitted to the observed azimuthal distribution of polarization angles. Faraday rotation, measured between 3.6 and 6.2 cm at a linear resolution of 0.7 kpc, shows more variation in the south than in the north of the galaxy. About 10% of the nonthermal emission from M33 at 3.6 cm is polarized. We estimate the average total and regular magnetic field strengths in M33 as ~ 6.4 and 2.5 μ\muG, respectively. Under the assumption that the disk of M33 is flat, the regular magnetic field consists of horizontal and vertical components: however the inferred vertical field may be partly due to a galactic warp. The horizontal field is represented by an axisymmetric (m=0) mode from 1 to 3 kpc radius and a superposition of axisymmetric and bisymmetric (m=0+1) modes from 3 to 5 kpc radius. An excess of differential Faraday rotation in the southern half together with strong Faraday dispersion in the southern spiral arms seem to be responsible for the north-south asymmetry in the observed wavelength dependent depolarization. The presence of an axisymmetric m=0 mode of the regular magnetic field in each ring suggests that a galactic dynamo is operating in M33. The pitch angles of the spiral regular magnetic field are generally smaller than the pitch angles of the optical spiral arms but are twice as big as simple estimates based on the mean-field dynamo theory and M33's rotation curve. Generation of interstellar magnetic fields from turbulent gas motions in M33 is indicated by the equipartition of turbulent and magnetic energy densities.Comment: 17 pages, 12 figures, accepted for Astronomy and Astrophysics publicatio

    A Faraday Rotation Template for the Galactic Sky

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    Using a set of compilations of measurements for extragalactic radio sources we construct all-sky maps of the Faraday Rotation produced by the Galactic magnetic field. In order to generate the maps we treat the radio source positions as a kind of "mask" and construct combinations of spherical harmonic modes that are orthogonal on the masked sky. As long as relatively small multipoles are used the resulting maps are quite stable to changes in selection criteria for the sources, and show clearly the structure of the local Galactic magnetic field. We also suggest the use of these maps as templates for CMB foreground analysis, illustrating the idea with a cross-correlation analysis between the Wilkinson Microwave Anisotropy Probe (WMAP) data and our maps. We find a significant cross-correlation, indicating the presence of significant residual contamination.Comment: 9 pages, 9 figures, accepted for publication in MNRA

    Perspective from a Younger Generation -- The Astro-Spectroscopy of Gisbert Winnewisser

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    Gisbert Winnewisser's astronomical career was practically coextensive with the whole development of molecular radio astronomy. Here I would like to pick out a few of his many contributions, which I, personally, find particularly interesting and put them in the context of newer results.Comment: 14 pages. (Co)authored by members of the MPIfR (Sub)millimeter Astronomy Group. To appear in the Proceedings of the 4th Cologne-Bonn-Zermatt-Symposium "The Dense Interstellar Medium in Galaxies" eds. S. Pfalzner, C. Kramer, C. Straubmeier, & A. Heithausen (Springer: Berlin

    Power spectrum of the polarized diffuse Galactic radio emission

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    We have analyzed the available polarization surveys of the Galactic emission to estimate to what extent it may be a serious hindrance to forthcoming experiments aimed at detecting the polarized component of Cosmic Microwave Background (CMB) anisotropies. Regions were identified for which independent data consistently indicate that depolarization must be small. The power spectrum of the polarized emission, in terms of antenna temperature, was found to be described by C(1.2±0.8)109(/450)1.8±0.3(ν/2.4GHz)5.8C_{\ell}\simeq (1.2\pm 0.8)\cdot 10^{-9}\cdot (\ell / 450)^{-1.8\pm 0.3}\cdot (\nu/ 2.4{\rm GHz})^{-5.8} K2^{2}, from arcminute to degree scales. Data on larger angular scales (100\ell\le 100) indicate a steeper slope 3\sim \ell^{-3}. We conclude that polarized Galactic emission is unlikely to be a serious limitation to CMB polarization measurements at the highest frequencies of the MAP and {\sc Planck}/LFI instruments, at least for 50\ell\ge 50 and standard cosmological models. The weak correlation between polarization and total power and the low polarization degree of radio emission close to the Galactic plane, found also in low-depolarization regions, is interpreted as due to large contributions to the observed intensity from unpolarized sources, primarily strong HII regions, concentrated on the Galactic plane. Thus estimates of the power spectrum of total intensity at low Galactic latitudes are not representative of the spatial distribution of Galactic emission far from the plane. Both total power and polarized emissions show highly significant deviations from a Gaussian distribution.Comment: 14 pages, including 15 figures, version accepted for publication on A&
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