New Hybrid Protected Lands Layer for Vermont Conservation Design Analysis (February 2019)

This shapefile (.shp) is a hybrid of the March 2017 Edition of the Vermont Center for Geographic Information\u27s (VCGI) Vermont Protected Lands Database (VPLD), the Vermont Land Trust\u27s February 2019 Protected Lands database, and The Nature Conservancy\u27s Secured Areas (SA 2018+) database. The VLT and SA 2018+ datasets were used as the scaffolding for the hybrid protected lands layer, with some VCGI VPLD polygons retained if they contained unique contributions. These datasets were combined by C.D. Loeb because each input dataset was missing some protected lands polygons in the state of Vermont. Additionally, the VCGI VPLD dataset contained many overlapping polygons, making it unusable for the area calculations of interest to our study on the overlap between formally protected lands and Vermont Conservation Design landscape-level targets (see publication reference). This hybrid protected lands layer creates a more complete snapshot of Vermont’s protected lands for our study’s purposes than any other known, publicly available dataset as of February 2019, and also corrects for all improperly overlapping polygons. However, we know that this hybrid product still does not capture all of Vermont\u27s protected lands. Specifically, some Upper Valley Land Trust-protected parcels are missing from this hybrid protected lands layer, and there are probably other protected parcels that could not be captured by the input datasets. Thus, our hybrid product will likely underrepresent actual protections. This layer was created to intersect with Vermont Conservation Design targets for input into the software Tableau. Its purpose was to perform cross tabulations to compare Vermont Conservation Design targets with protected lands in Vermont to-date, and to calculate acreages of protected lands that are also design targets by primary protecting agency. All parcel attributes and delineations in the hybrid output are only as good as the parent datasets. In areas where parcels were digitized differently between parent datasets, “slivers” may have been generated by merging them. Our study objectives originally included an analysis of the GAP Status of protected lands in Vermont (reflected in this layer\u27s metadata); however, some serious errors were detected in parent datasets with regards to GAP Status, so GAP Status was discarded as an analysis object. Please note author-identified GAP Status issues if using this dataset. Please see the shapefile\u27s metadata for detailed creation steps. The user implies knowledge of the limitations of this dataset. This dataset should not be used to ascertain boundaries or legal acreages for any parcels. Note: This version of the hybrid protected lands layer does not have county boundaries embedded in it nor waterbodies excluded from it, since it was created to capture all formally protected lands in the state of Vermont to the best of the authors’ abilities. Prior to use in our analysis, this layer was modified to exclude waterbodies and to introduce county boundaries. To obtain the same hybrid protected lands layer with county boundaries embedded in it and waterbodies excluded from it, please contact C. D. Loeb at [email protected]

Reionization of Hydrogen and Helium by Early Stars and Quasars

We compute the reionization histories of hydrogen and helium due to the ionizing radiation fields produced by stars and quasars. For the quasars we use a model based on halo-merger rates that reproduces all known properties of the quasar luminosity function at high redshifts. The less constrained properties of the ionizing radiation produced by stars are modeled with two free parameters: (i) a transition redshift, z_tran, above which the stellar population is dominated by massive, zero-metallicity stars and below which it is dominated by a Scalo mass function; (ii) the product of the escape fraction of stellar ionizing photons from their host galaxies and the star-formation efficiency, f_esc f_*. We constrain the allowed range of these free parameters at high redshifts based on the lack of the HI Gunn-Peterson trough at z<6 and the upper limit on the total intergalactic optical depth for electron scattering, tau_es<0.18, from recent cosmic microwave background (CMB) experiments. We find that quasars ionize helium by a redshift z~4, but cannot reionize hydrogen by themselves before z~6. A major fraction of the allowed combinations of f_esc f_* and z_tran lead to an early peak in the ionized fraction due to metal-free stars at high redshifts. This sometimes results in two reionization epochs, namely an early HII or HeIII overlap phase followed by recombination and a second overlap phase. Even if early overlap is not achieved, the peak in the visibility function for scattering of the CMB often coincides with the early ionization phase rather than with the actual reionization epoch. Consequently, tau_es does not correspond directly to the reionization redshift. We generically find values of tau_es>7%, that should be detectable by the MAP satellite.Comment: 33 pages, 10 figures, Accepted for publication in Ap

The Impact of Cell Phones and BAC Laws on Motor Vehicle Fatality Rates

This paper develops a set of models for the determinants of automobile fatalities with particular attention devoted to the effects of increased cell phone usage. Cell phones have been associated with both life-taking and life-saving properties. However, prior statistical evaluations of the effects of cell phones have led to fragile results. We develop in this paper econometric models using time series data, allowing for polynomial structures of the regressors. The models are evaluated with a set of specification error tests providing reliable estimates of the effects of the various policy and driving related variables evaluated. The statistical results indicate the effect of cell phones is non-monotonic depending on the volume of phones in use, first having a net life-taking effect, then a net life-saving effect, followed finally with a net life-taking effect as the volume of phone use increases.Motor Vehicle Fatalities, Cell Phones, BAC Laws

Prestige and piety in the Iranian synagogue

Journal ArticleAmong Iranian Jews, long deprived of meaningful political power and afraid to conspicuously display material wealth, relative prestige became more valued that authority of opulence. The synagogue provides the traditional public forum where meaningful interaction among its members reinforces rand differences. Through a network of concerns centering upon the apportioning of ritual honors, the synagogue provides mechanisms fro limited social mobility. This paper examines the processes of selecting the recipients of these honors, the strategies of participation and their manipulation by the potential social climber

A Model Connecting Galaxy Masses, Star Formation Rates, and Dust Temperatures Across Cosmic Time

We investigate the evolution of dust content in galaxies from redshifts z=0 to z=9.5. Using empirically motivated prescriptions, we model galactic-scale properties -- including halo mass, stellar mass, star formation rate, gas mass, and metallicity -- to make predictions for the galactic evolution of dust mass and dust temperature in main sequence galaxies. Our simple analytic model, which predicts that galaxies in the early Universe had greater quantities of dust than their low-redshift counterparts, does a good job at reproducing observed trends between galaxy dust and stellar mass out to z~6. We find that for fixed galaxy stellar mass, the dust temperature increases from z=0 to z=6. Our model forecasts a population of low-mass, high-redshift galaxies with interstellar dust as hot as, or hotter than, their more massive counterparts; but this prediction needs to be constrained by observations. Finally, we make predictions for observing 1.1-mm flux density arising from interstellar dust emission with the Atacama Large Millimeter Array.Comment: Accepted for publication in Ap

Scattered Lyman-alpha Radiation Around Sources Before Cosmological Reionization

The spectra of the first galaxies and quasars in the Universe should be strongly absorbed shortward of their rest-frame Lyman-alpha wavelength by neutral hydrogen (HI) in the intervening intergalactic medium. However, the Lyman-alpha line photons emitted by these sources are not eliminated but rather scatter until they redshift out of resonance and escape due to the Hubble expansion of the surrounding intergalactic HI. We calculate the resulting brightness distribution and the spectral shape of the diffuse Lyman-alpha line emission around high redshift sources, before the intergalactic medium was reionized. Typically, the Lyman-alpha photons emitted by a source at z=10 scatter over a characteristic angular radius of order 15 arcseconds around the source and compose a line which is broadened and redshifted by about a thousand km/s relative to the source. The scattered photons are highly polarized. Detection of the diffuse Lyman-alpha halos around high redshift sources would provide a unique tool for probing the neutral intergalactic medium before the epoch of reionization. On sufficiently large scales where the Hubble flow is smooth and the gas is neutral, the Lyman-alpha brightness distribution can be used to determine the cosmological mass densities of baryons and matter.Comment: 21 pages, 5 Postscript figures, accepted by ApJ; figures 1--3 corrected; new section added on the detectability of Lyman alpha halos; conclusions update

A Dynamical Method for Measuring Masses of Stars with Transiting Planets

As a planet transits the face of a star, it accelerates along the line-of-sight. The changing delay in the propagation of photons produces an apparent deceleration of the planet across the sky throughout the transit. This persistent transverse deceleration breaks the time-reversal symmetry in the transit lightcurve of a spherical planet in a circular orbit around a perfectly symmetric star. For `hot Jupiter' systems, ingress advances at a higher rate than egress by a fraction of 10^{-4}-10^{-3}. Forthcoming space telescopes such as Kepler or COROT will reach the sensitivity required to detect this asymmetry. The scaling of the fractional asymmetry with stellar mass M and planetary orbital radius R as M/R^2 is different from the scaling of the orbital period as (M/R^3)^{-1/2}. Therefore, this effect constitutes a new method for a purely dynamical determination of the mass of the star, which is currently inferred indirectly with theoretical uncertainties based on spectral modeling. Radial velocity data for the reflex motion of the star can then be used to determine the planet's mass. Although orbital eccentricity could introduce a larger asymmetry than the light propagation delay, the eccentricity is expected to decay by tidal dissipation to negligible values for a close-in planet with no perturbing third body. Future detection of the eclipse of a planet's emission by its star could be used to measure the light propagation delay across the orbital diameter, 46.7(R/7x10^{11}cm) seconds, and also determine the stellar mass from the orbital period.Comment: 4 pages, 2 figures, submitted to ApJ

Measuring the Direction and Angular Velocity of a Black Hole Accretion Disk via Lagged Interferometric Covariance

We show that interferometry can be applied to study irregular, rapidly rotating structures, as are expected in the turbulent accretion flow near a black hole. Specifically, we analyze the lagged covariance between interferometric baselines of similar lengths but slightly different orientations. For a flow viewed close to face-on, we demonstrate that the peak in the lagged covariance indicates the direction and angular velocity of the emission pattern from the flow. Even for moderately inclined flows, the covariance robustly estimates the flow direction, although the estimated angular velocity can be significantly biased. Importantly, measuring the direction of the flow as clockwise or counterclockwise on the sky breaks a degeneracy in accretion disk inclinations when analyzing time-averaged images alone. We explore the potential efficacy of our technique using three-dimensional, general relativistic magnetohydrodynamic (GRMHD) simulations, and we highlight several baseline pairs for the Event Horizon Telescope (EHT) that are well-suited to this application. These results indicate that the EHT may be capable of estimating the direction and angular velocity of the emitting material near Sagittarius A*, and they suggest that a rotating flow may even be utilized to improve imaging capabilities.Comment: 8 Pages, 4 Figures, accepted for publication in Ap

Redshifted 21cm Signatures Around the Highest Redshift Quasars

The Ly-alpha absorption spectrum of the highest redshift quasars indicates that they are surrounded by giant HII regions, a few Mpc in size. The neutral gas around these HII regions should emit 21cm radiation in excess of the Cosmic Microwave Background, and enable future radio telescopes to measure the transverse extent of these HII regions. At early times, the HII regions expand with a relativistic speed. Consequently, their measured sizes along the line-of-sight (via Ly-alpha absorption) and transverse to it (via 21 cm emission) should have different observed values due to relativistic time-delay. We show that the combined measurement of these sizes would directly constrain the neutral fraction of the surrounding intergalactic medium (IGM) as well as the quasar lifetime. Based on current number counts of luminous quasars at z>6, an instrument like LOFAR should detect >2 redshifted 21cm shells per field (with a radius of 11 degrees) around active quasars as bright as those already discovered by SDSS, and >200 relic shells of inactive quasars per field. We show that Ly-alpha photons from the quasar are unable to heat the IGM or to couple the spin and kinetic temperatures of atomic hydrogen beyond the edge of the HII region. The detection of the IGM in 21cm emission around high redshift quasars would therefore gauge the presence of a cosmic Ly-alpha background during the reionization epoch.Comment: 11 pages, 6 figures. Submitted to Ap