Implications of the VHE Gamma-Ray Detection of the Quasar 3C279

The MAGIC collaboration recently reported the detection of the quasar 3C279 at > 100 GeV gamma-ray energies. Here we present simultaneous optical (BVRI) and X-ray (RXTE PCA) data from the day of the VHE detection and discuss the implications of the snap-shot spectral energy distribution for jet models of blazars. A one-zone synchrotron-self-Compton origin of the entire SED, including the VHE gamma-ray emission can be ruled out. The VHE emission could, in principle, be interpreted as Compton upscattering of external radiation (e.g., from the broad-line regions). However, such an interpretation would require either an unusually low magnetic field of B ~ 0.03 G or an unrealistically high Doppler factor of Gamma ~ 140. In addition, such a model fails to reproduce the observed X-ray flux. This as well as the lack of correlated variability in the optical with the VHE gamma-ray emission and the substantial gamma-gamma opacity of the BLR radiation field to VHE gamma-rays suggests a multi-zone model. In particular, an SSC model with an emission region far outside the BLR reproduces the simultaneous X-ray -- VHE gamma-ray spectrum of 3C279. Alternatively, a hadronic model is capable of reproducing the observed SED of 3C279 reasonably well. However, the hadronic model requires a rather extreme jet power of L_j ~ 10^{49} erg s^{-1}, compared to a requirement of L_j ~ 2 X 10^{47} erg s^{-1} for a multi-zone leptonic model.Comment: Accepted for pulication. Several clarifications and additions to the manuscript to match the accepted versio

Keep Ballots Secret: On the Futility of Social Learning in Decision Making by Voting

We show that social learning is not useful in a model of team binary decision making by voting, where each vote carries equal weight. Specifically, we consider Bayesian binary hypothesis testing where agents have any conditionally-independent observation distribution and their local decisions are fused by any L-out-of-N fusion rule. The agents make local decisions sequentially, with each allowed to use its own private signal and all precedent local decisions. Though social learning generally occurs in that precedent local decisions affect an agent's belief, optimal team performance is obtained when all precedent local decisions are ignored. Thus, social learning is futile, and secret ballots are optimal. This contrasts with typical studies of social learning because we include a fusion center rather than concentrating on the performance of the latest-acting agents

A complexity analysis of statistical learning algorithms

We apply information-based complexity analysis to support vector machine (SVM) algorithms, with the goal of a comprehensive continuous algorithmic analysis of such algorithms. This involves complexity measures in which some higher order operations (e.g., certain optimizations) are considered primitive for the purposes of measuring complexity. We consider classes of information operators and algorithms made up of scaled families, and investigate the utility of scaling the complexities to minimize error. We look at the division of statistical learning into information and algorithmic components, at the complexities of each, and at applications to support vector machine (SVM) and more general machine learning algorithms. We give applications to SVM algorithms graded into linear and higher order components, and give an example in biomedical informatics

Compressive X-ray phase tomography based on the transport of intensity equation

We develop and implement a compressive reconstruction method for tomographic recovery of refractive index distribution for weakly attenuating objects in a microfocus X-ray system. This is achieved through the development of a discretized operator modeling both the transport of intensity equation and X-ray transform that is suitable for iterative reconstruction techniques

Review of: Tugrul Keskin, Ed. The Sociology of Islam: Secularism, Economy and Politics

This is a print version of the article published in Review of Middle East Studies 46(1):121-3. The version made available in Digital Common was supplied by the author, and permission to publish it online has been obtained from the publisher

A study of Massachusetts Society for the Prevention of Cruelty to Children referrals to the Judge Baker Guidance Center, 1938-1939

Thesis (M.S.)--Boston University, 194

Merit and Mothering: Women and Social Welfare in Taiwanese Buddhism

This is a publisher's version of an article published in The Journal of Asian Studies in 1998. The offprint is posted here in accordance with existing publisher policy, or by special permission via correspondence.tru

From Dynamic to Expressionism: An Arts Integration Study

The classroom based study “From Dynamic to Expressionism: An Arts Integration Study” was designed to answer the question; Will implementing an interdisciplinary art and music unit affect the level of student confidence in understanding expressionism in art? The researcher implemented an interdisciplinary art unit in two inner-city second grade classes. Throughout the study a survey was used for students to assess their confidence level and a checklist was used to observe student confidence during class time

A study of the satisfactions of convalescent psychiatric patients

Thesis (M.S.)--Boston Universit

The X-ray spectrometer and what it reveals

Thesis (M.A.)--Boston Universit