Finding Your Literature Match -- A Recommender System

The universe of potentially interesting, searchable literature is expanding continuously. Besides the normal expansion, there is an additional influx of literature because of interdisciplinary boundaries becoming more and more diffuse. Hence, the need for accurate, efficient and intelligent search tools is bigger than ever. Even with a sophisticated search engine, looking for information can still result in overwhelming results. An overload of information has the intrinsic danger of scaring visitors away, and any organization, for-profit or not-for-profit, in the business of providing scholarly information wants to capture and keep the attention of its target audience. Publishers and search engine engineers alike will benefit from a service that is able to provide visitors with recommendations that closely meet their interests. Providing visitors with special deals, new options and highlights may be interesting to a certain degree, but what makes more sense (especially from a commercial point of view) than to let visitors do most of the work by the mere action of making choices? Hiring psychics is not an option, so a technological solution is needed to recommend items that a visitor is likely to be looking for. In this presentation we will introduce such a solution and argue that it is practically feasible to incorporate this approach into a useful addition to any information retrieval system with enough usage.Comment: Contribution to the proceedings of the colloquium Future Professional Communication in Astronomy II, 13-14 April 2010, Cambridge, Massachusetts. 11 pages, 4 figures

Convergent flows and low-velocity shocks in DR21(OH)

DR21(OH) is a pc-scale massive, 7000 Msun clump hosting three massive dense cores (MDCs) at an early stage of their evolution. We present a high angular-resolution mosaic, covering 70" by 100", with the IRAM PdBI at 3 mm to trace the dust continuum emission and the N2H+ (J=1-0) and CH3CN (J=5-4) molecular emission. The cold, dense gas traced by the compact emission in N2H+ is associated with the three MDCs and shows several velocity components towards each MDC. These velocity components reveal local shears in the velocity fields which are best interpreted as convergent flows. Moreover, we report the detection of weak extended emission from CH3CN at the position of the N2H+ velocity shears. We propose that this extended CH3CN emission is tracing warm gas associated with the low-velocity shocks expected at the location of convergence of the flows where velocity shears are observed. This is the first detection of low-velocity shocks associated with small (sub-parsec) scale convergent flows which are proposed to be at the origin of the densest structures and of the formation of (high-mass) stars. In addition, we propose that MDCs may be active sites of star-formation for more than a crossing time as they continuously receive material from larger scale flows as suggested by the global picture of dynamical, gravity driven evolution of massive clumps which is favored by the present observations.Comment: 6 pages, 4 figures, Accepted for publication in the Astrophysical Journal Letter

Preferences for redistribution and tax burdens in Latin America

Diverse studies of the political economy of tax composition across middleincome countries have found that Latin American economies tax upperincome groups much less than do other developing regions, such as East Asia and Eastern Europe (i.e. Di John 2006; Mahon, Chapter 8 in this volume). As the Introduction to this volume suggests, this finding is consistent with the relatively low redistributive capacity Latin American states display when compared to advanced capitalist societies. Sharp within-region differences remain even during periods of significant inequality reduction in the region, such as during the most recent decade (see Lustig and Pereira 2016). Against this backdrop, this chapter analyzes cross-national differences in how distributive preferences map onto class and political attitudes

Different Evolutionary Stages in the Massive Star Forming Region S255 Complex

To understand evolutionary and environmental effects during the formation of high-mass stars, we observed three regions of massive star formation at different evolutionary stages that reside in the same natal molecular cloud. Methods. The three regions S255IR, S255N and S255S were observed at 1.3 mm with the Submillimeter Array (SMA) and followup short spacing information was obtained with the IRAM 30m telescope. Near infrared (NIR) H + K-band spectra and continuum observations were taken for S255IR with VLT-SINFONI to study the different stellar populations in this region. The combination of millimeter (mm) and near infrared data allow us to characterize different stellar populations within the young forming cluster in detail. While we find multiple mm continuum sources toward all regions, their outflow, disk and chemical properties vary considerably. The most evolved source S255IR exhibits a collimated bipolar outflow visible in CO and H2 emission, the outflows from the youngest region S255S are still small and rather confined in the regions of the mm continuum peaks. Also the chemistry toward S255IR is most evolved exhibiting strong emission from complex molecules, while much fewer molecular lines are detected in S255N, and in S255S we detect only CO isotopologues and SO lines. Also, rotational structures are found toward S255N and S255IR. Furthermore, a comparison of the NIR SINFONI and mm data from S255IR clearly reveal two different (proto) stellar populations with an estimated age difference of approximately 1 Myr. A multi-wavelength spectroscopy and mapping study reveals different evolutionary phases of the star formation regions. We propose the triggered outside-in collapse star formation scenario for the bigger picture and the fragmentation scenario for S255IR.Comment: 23 pages,25 figures, accepted by A&

A Mid-Infrared Census of Star Formation Activity in Bolocam Galactic Plane Survey Sources

We present the results of a search for mid-infrared signs of star formation activity in the 1.1 mm sources in the Bolocam Galactic Plane Survey (BGPS). We have correlated the BGPS catalog with available mid-IR Galactic plane catalogs based on the Spitzer Space Telescope GLIMPSE legacy survey and the Midcourse Space Experiment (MSX) Galactic plane survey. We find that 44% (3,712 of 8,358) of the BGPS sources contain at least one mid-IR source, including 2,457 of 5,067 (49%) within the area where all surveys overlap (10 deg < l < 65 deg). Accounting for chance alignments between the BGPS and mid-IR sources, we conservatively estimate that 20% of the BPGS sources within the area where all surveys overlap show signs of active star formation. We separate the BGPS sources into four groups based on their probability of star formation activity. Extended Green Objects (EGOs) and Red MSX Sources (RMS) make up the highest probability group, while the lowest probability group is comprised of "starless" BGPS sources which were not matched to any mid-IR sources. The mean 1.1 mm flux of each group increases with increasing probability of active star formation. We also find that the "starless" BGPS sources are the most compact, while the sources with the highest probability of star formation activity are on average more extended with large skirts of emission. A subsample of 280 BGPS sources with known distances demonstrates that mass and mean H_2 column density also increase with probability of star formation activity.Comment: 20 pages, 12 figures, 3 tables. Accepted for publication in ApJ. Full Table 2 will be available online through Ap

Digging into NGC 6334I(N): Multiwavelength Imaging of a Massive Protostellar Cluster

We present a high-resolution, multi-wavelength study of the massive protostellar cluster NGC 6334I(N) that combines new spectral line data from the Submillimeter Array (SMA) and VLA with a reanalysis of archival VLA continuum data, 2MASS and Spitzer images. As shown previously, the brightest 1.3 mm source SMA1 contains substructure at subarcsecond resolution, and we report the first detection of SMA1b at 3.6 cm along with a new spatial component at 7 mm (SMA1d). We find SMA1 (aggregate of sources a, b, c, and d) and SMA4 to be comprised of free-free and dust components, while SMA6 shows only dust emission. Our 1.5" resolution 1.3 mm molecular line images reveal substantial hot-core line emission toward SMA1 and to a lesser degree SMA2. We find CH3OH rotation temperatures of 165\pm 9 K and 145\pm 12 K for SMA1 and SMA2, respectively. We estimate a diameter of 1400 AU for the SMA1 hot core emission, encompassing both SMA1b and SMA1d, and speculate that these sources comprise a >800 AU separation binary that may explain the previously-suggested precession of the outflow emanating from the SMA1 region. The LSR velocities of SMA1, SMA2, and SMA4 all differ by 1-2 km/s. Outflow activity from SMA1, SMA2, SMA4, and SMA6 is observed in several molecules including SiO(5--4) and IRAC 4.5 micron emission; 24 micron emission from SMA4 is also detected. Eleven water maser groups are detected, eight of which coincide with SMA1, SMA2, SMA4, and SMA6. We also detect a total of 83 Class I CH3OH 44GHz maser spots which likely result from the combined activity of many outflows. Our observations paint the portrait of multiple young hot cores in a protocluster prior to the stage where its members become visible in the near-infrared.Comment: Accepted to ApJ, 24 pages, a full high resolution version is available at http://www.cv.nrao.edu/~cbrogan/ms.long.pd

CoRoT\,102699796, the first metal-poor Herbig Ae pulsator: a hybrid δ\delta Sct-γ\gamma Dor variable?

We present the analysis of the time series observations of CoRoT\,102699796 obtained by the CoRoT satellite that show the presence of five independent oscillation frequencies in the range 3.6-5 c/d. Using spectra acquired with FLAMES@VLT, we derive the following stellar parameters: spectral type F1V, T$_{\rm eff}$=7000$\pm$200 K, log(g)=$3.8\pm0.4$, [M/H]=$-1.1\pm0.2$, $v$sin$i$=$50\pm5$ km/s, L/L$_{\odot}$=21$^{+21}_{-11}$. Thus, for the first time we report the existence of a metal poor, intermediate-mass PMS pulsating star. Ground-based and satellite data are used to derive the spectral energy distribution of CoRoT\,102699796 extending from the optical to mid-infrared wavelengths. The SED shows a significant IR excess at wavelengths greater than $\sim5 \mu$. We conclude that CoRoT\,102699796 is a young Herbig Ae (F1Ve) star with a transitional disk, likely associated to the HII region [FT96]213.1-2.2. The pulsation frequencies have been interpreted in the light of the non-radial pulsation theory, using the LOSC code in conjunction with static and rotational evolutionary tracks. A minimization algorithm was used to find the best-fit model with M=1.84 M$_{\odot}$, T$_{\rm eff}$=6900 K which imply an isochronal age of t$\sim$2.5 Myr. This result is based on the interpretation of the detected frequencies as $g$-modes of low-moderate $n$-value. To our knowledge, this is the first time that such modes are identified in a intermediate-mass PMS pulsating star. Since CoRoT\,102699796 lies in the region of the HR diagram where the $\delta$ Sct and $\gamma$ Dor instability strips intersect, we argue that the observed pulsation characteristics are intermediate between these classes of variables, i.e. CoRoT\,102699796 is likely the first PMS hybrid $\gamma$ Dor-$\delta$ Sct pulsator ever studied.Comment: 13 pages, 7 figures. Accepted for publication in Monthly Notices of the RA

SECURITY RISK ANALYSIS AND EVALUATION OF INTEGRATING CUSTOMER ENERGY MANAGEMENT SYSTEMS INTO SMART DISTRIBUTION GRIDS

ABSTRAC