The Effects of Class Size on the Long Run Growth in Reading Abilities and Early Adult Outcomes in the Christchurch Health and Development Study

This paper utilizes the feature of the CHDS data from New Zealand that children are sampled for extremely long individual histories of their class size experiences as well as their scholastic and early labor market outcomes. Our interest is to explore the full set of empirical implications of the recent experimental evidence on class size effects on student achievement from the United States in Project STAR for observational data. We argue that one implication of Project STAR is that only persistent class size reduction policies may have detectable effects, and so the longitudinal aspect of CHDS is necessary to detect class size effects. We account for the observational nature of the CHDS (in that children were not randomly assigned to different class sizes) by examining the long-run trends in test score growth, rather than levels. Consistent with the experimental evidence, we find statistically and economically significant effects of children being assigned to persistently smaller classes on both childhood test score growth as well as on early adult outcomes. Our analysis points the way towards the unification of experimental and observational evidence on class size effects, as well as highlighting several possible pitfalls in the analysis of observational data on this topic.School Quality; Value-Added Model; Experimental Evidence

Living Standards in Black and White: Evidence from the Heights of Ohio Prison Inmates, 1829 – 1913

The use of height data to measure living standards is now a well-established method in the economic history literature. Moreover, a number of core findings in this literature are widely agreed upon. There are still some populations, places, and times, however, for which anthropometric evidence remains thin. One example is African-Americans in the Northern US in the 1800s. Here, we use new data from the state prison in Ohio to track heights of black and white men from 1829 to 1913. We corroborate the well-known mid-century height decline among white men in Ohio, found by Steckel and Haurin (1994) using National Guard data. We find that black men in Ohio were shorter than white men, throughout the century and controlling for a number of characteristics. We also find a pattern of height decline in mid-century similar to that found for white men.

A Chandra observation of the H2O megamaser IC2560

A short Chandra ACIS-S observation of the Seyfert 2 galaxy IC 2560, which hosts a luminous nuclear water megamaser, shows: 1) the X-ray emission is extended; 2) the X-ray spectrum shows emission features in the soft (E<2 keV) X-ray band; this is the major component of the extended emission; and 3) a very strong (EW~3.6 keV) iron K line at 6.4 keV on a flat continuum. This last feature clearly indicates that the X-ray source is hidden behind Compton-thick obscuration, so that the intrinsic hard X-ray luminosity must be much higher than observed, probably close to ~3e42 erg/s. We briefly discuss the implications for powering of the maser emission and the central source.Comment: 5 pages, MNRAS in pres

Retrofitting O'Raifeartaigh Models with Dynamical Scales

We provide a method for obtaining simple models of supersymmetry breaking, with all small mass scales generated dynamically, and illustrate it with explicit examples. We start from models of perturbative supersymmetry breaking, such as O'Raifeartaigh and Fayet models, that would respect an $R$ symmetry if their small input parameters transformed as the superpotential does. By coupling the system to a pure supersymmetric Yang-Mills theory (or a more general supersymmetric gauge theory with dynamically small vacuum expectation values), these parameters are replaced by powers of its dynamical scale in a way that is naturally enforced by the symmetry. We show that supersymmetry breaking in these models may be straightforwardly mediated to the supersymmetric Standard Model, obtain complete models of direct gauge mediation, and comment on related model building strategies that arise in this simple framework.Comment: 15 pages, harvmac bi

One-loop partition function of three-dimensional flat gravity

In this note we point out that the one-loop partition function of three-dimensional flat gravity, computed along the lines originally developed for the anti-de Sitter case, reproduces characters of the BMS3 group.Comment: 8 pages. v2: Minor misprints corrected, reference [10] updated. Published in JHE

L'CO/LFIR Relations with CO Rotational Ladders of Galaxies Across the Herschel SPIRE Archive

We present a catalog of all CO (J=4-3 through J=13-12)), [CI], [NII] lines available from extragalactic spectra from the Herschel SPIRE Fourier Transform Spectrometer (FTS) archive combined with observations of the low-J CO lines from the literature and from the Arizona Radio Observatory. This work examines the relationships between LFIR, L'CO, and LCO/LCO(1-0). We also present a new method for estimating probability distribution functions (PDFs) from marginal signal-to-noise ratio Herschel} FTS spectra, which takes into account the instrumental "ringing" and the resulting highly correlated nature of the spectra. The slopes of log(LFIR) vs. log(L'CO) are linear for all mid- to high-J CO lines and slightly sublinear if restricted to (U)LIRGs. The mid- to high-J CO luminosity relative to CO J=1-0 increases with increasing LFIR, indicating higher excitement of the molecular gas, though these ratios do not exceed ~ 180. For a given bin in LFIR, the luminosities relative to CO J=1-0 remain relatively flat from J=6-5 through J=13-12, across three orders of magnitude of LFIR. A single component theoretical photon-dominated region (PDR) model cannot match these flat SLED shapes, though combinations of PDR models with mechanical heating added qualitatively match the shapes, indicating the need for further comprehensive modeling of the excitation processes of warm molecular gas in nearby galaxies.Comment: 17 pages, 4 figures (including appendix), accepted by ApJ. Full tables will be in VizieR upon publication, email first author for tables in the meantim

Anti-Jam GPS Controlled Reception Pattern Antennas for Man-Portable Applications

Military GPS receivers provide crucial information to soldiers in the field, however, the performance of these devices is degraded by in band RF interference, making GPS susceptible to jamming. Anti-jam techniques for aircraft and vehicular platforms have been developed, but at present there is no system for dismounted soldiers. There is a need for an anti-jam system which meets the demands of a dismounted soldier and conforms to the size, weight, and power requirements of a portable device. A controlled reception pattern antenna, or CRPA, is a potential solution for jammer mitigation. These devices work by steering reception pattern nulls toward the jammer direction, reducing the jammer power which reaches the GPS receiver. Prior CRPA realizations have been designed for use on vehicular and aircraft applications, however, these platforms do not suffer from the same limitations as a man-portable CRPA. Three considerations which are more pertinent for man-portable designs than prior work are (i) distributed antenna element positions and orientations dynamically change during use changing the reception pattern characteristics, (ii) the user is lower to the ground and moves through the environment meaning that multipath propagation can have a greater effect on CRPA performance, and (iii) the size weight and power constraints for a portable system limit the number of antenna elements reducing the degrees of freedom that can be used for cancellation. To address these challenges, a framework for man-portable CRPA modeling is presented. This includes development of efficient modeling methods which enable investigations into element perturbations to address the dynamic orientation problem. These and other methods are presented in Chapter 3, along with a discussion of the relative strengths and weaknesses of each. Additionally, a mixed scattering channel model is applied to the CRPA reception patterns, combining diffuse and specular reflection in Chapter 4. Discussion of this model centers around the eigenvalues of the signal covariance matrix and the effect of coherence between multipath components. Following this, Chapter 5 examines the performance of polarimetric CRPAs and space-time adaptive processing for man-portable CRPAs with limited degrees of freedom

Human Rights and Healthy Societies: Opening Social and Cultural Spaces for Peacebuilding

Exploring peace demands rethinking many of the assumptions that have driven the field of peacebuilding. Previously, scholars have investigated the content of peace agreements in relation to the promotion of sectors that include security, justice, and democracy. However, I hypothesize that by focusing narrowly on these areas, scholars and peacemakers overlook crucial ingredients that create stable post-conflict societies. This senior thesis examines the inclusion of social and cultural rights in peace agreements and aims to contribute to a more robust understanding of whether traditionally “soft” issues like education, art, and women’s participation may have significant impacts on the long-term health of society—and therefore positively influence the root causes of conflict. I study the transitional processes in Northern Ireland to determine how a human rights based approach to peace agreements and peace processes, specifically the inclusion of social and cultural rights protections, relates to the prospects for sustainable peace and a healthy post-conflict society. I make conclusions about the contributions a human rights based approach makes while considering the challenges to achieving a sustainable peace and healthy society both in Northern Ireland’s context specifically and more broadly